Modal Analysis Approach on Vehicle Transient Behavior
-Considering Roll and Pitch Dynamics-

Kaoru Kusaka･Takahiro Yuhara･Shingo Koakutsu (Honda Motor)

Vehicle dynamics are primarily governed by planar motion; however, roll and pitch significantly influence handling and subjective evaluation. Prior studies suggest that phase differences between roll and pitch during turn-in affect driver perception. While modal analysis has been applied to motorcycles, its use for four-wheel vehicles remains limited. This study formulates a four-degree-of-freedom model incorporating roll and pitch and solves the complex eigenvalue problem analytically to extract vibration modes. Furthermore, by demonstrating that vehicle behavior results from the superposition of these modes, the underlying mechanism of sprung-mass motion is elucidated.

Analysis of Handling Stability under Combined Steering and Road Irregularity Inputs (Second Report)

Ayumu Tanaka･Yasuji Shibahata･Makoto Yamakado･Masaki Yamamoto･Masato Abe･Yoshio Kano (Kanagawa Institute of Technology)

In the first report, a 5-degree-of-freedom motion model considering road surface irregularities was constructed, and the influence of suspension friction on handling and stability was analyzed. In this report, the effect of front-rear wheel friction force difference on the initial alignment effect is investigated, and it is shown that, under certain conditions, the yaw damping effect is less than the lateral force understeer. Similarly, an analysis will be conducted on the stroke velocity dependence of the damping force.

Derivation of Steering System Resonance Frequency for Steering Torque Response Design
-High-Accuracy Modeling of Dynamic Response as a Component of Steering Feel-

Hideki Sakai (Kindai University)

The author classifies steering feel into three components: 1) the quasi-static angle–force characteristics, 2) the rear-wheel lateral force transmitted to the steering wheel, and 3) the steering wheel's response to steering torque. The last component is referred to as force control, whose characteristic equation becomes a fourth-order equation because the steering system and the vehicle system are coupled. Intuition was used in formulating high-accuracy approximation formulas for their resonance frequencies. In this paper, we theoretically derive these formulas based on analytical considerations and further improve their approximation accuracy.

Mathematical Model of Vehicle Dynamics for Drifting in Motor Sports

Yoshio Adachi (Independent Researcher)

Drifting in motorsports utilizes traction force as centripetal force during cornering; therefore, modeling of the traction force is indispensable. In this study, we introduce a vehicle model that incorporates a kinetic-friction tire model focusing on contact patch velocity, enabling analytical calculations. Furthermore, we examine the steering angle and slip angle in drifting of four-wheel-drive vehicles.

Evaluation Method for Vehicle Steering Characteristics during the Transition from Straight Driving to Circular Turning

Haru Saito･Hiromasa Mochizuki･Masato Abe･Makoto Yamakado･Yoshio Kano･Masaki Yamamoto (Kanagawa Institute of Technology)

An extension of the conventional τL-based evaluation method derived from lane-change maneuvers was developed to assess the steering process from straight driving to circular turning. Full-scale vehicle tests confirmed that the corner-entry position for circular turning and the trigger position that defines the steering-onset point are key parameters. Tests with and without the control further demonstrated that the proposed method enables quantitative identification of steering characteristics during the formation of circular turning.

Influence of Suspension Ball Joints on Driver Steering Characteristics Evaluation

Yuto Kinoshita･Kei Ishitsuka (Kanagawa Institute of Technology)･Kenji Yabe･Shin Hirano (HKS)･Shogo Kawamori (Somic Ishikawa)･Masato Abe･Yoshio Kano･Masaki Yamamoto･Makoto Yamakado (Kanagawa Institute of Technology)

A vehicle equipped with a pillow-ball upper mount and a large negative camber setting showed higher subjective ratings in circuit driving when the stiffness of the front steering-side suspension ball joint was linearized compared with the normal specification. Steering characteristics were further evaluated using lane-change τL and steady-state cornering τL, through which the superiority of the linearized-stiffness specification was quantitatively confirmed.

Evaluation Method of Vehicle Steering Characteristics under Straight-Driving Disturbances

Reon Suzuki･Haru Saito･Kai Utsumi･Makoto Yamakado･Yoshio Kano･Masato Abe･Masaki Yamamoto･Ikuo Kushiro (Kanagawa Institute of Technology)･Jun Ishio (Honda Motor)

An extension of the conventional τL-based evaluation derived from lane-change maneuvers is proposed to assess vehicle steering characteristics under external disturbances during straight-line driving. Multiple vehicle responses and steering reaction forces were reproduced and analyzed in a driving simulator to verify the method. The results indicate that the approach complements traditional lane-change evaluations and provides a quantitative means of capturing steering behavior under disturbance inputs.

A Fundamental Interpretation of the Coupling Structure between Steering Systems and Vehicle Dynamics

Jun Ishio (Honda Motor)･Masaki Yamamoto･Masato Abe･Makoto Yamakado (Kanagawa Institute of Technology)

The influence of steering system characteristics on vehicle dynamics in the region of small lateral acceleration during cornering is well recognized. This study introduces an analytical approach that linearizes the nonlinear properties of the steering system and evaluates the combined behavior of the steering mechanism and vehicle dynamics. The proposed method effectively captures steering response characteristics under low-frequency steering inputs, providing a robust framework for systematic analysis.

Study on Improving the Accuracy of Stroke Sensors for Steer-by-Wire EPS

Yohei Shirakawa･Yoshiaki Yanagisawa･Yukio Ikeda (PROTERIAL)

An inductive sensor resistant to external magnetic fields was adopted for the stroke sensor that directly detects the rack shaft position in steer-by-wire EPS. To enhance sensor accuracy, we proposed optimizing the receiver coil shape and applying harmonic correction. Electromagnetic field simulations verified effectiveness, reducing error from 3.60% FS to 0.22% FS.

Adaptive Yawrate Control based on Cornering Detection in Electric Rear Wheel Steering

Taehong Kim (Hyundai Mobis)

This paper proposes an algorithm for electric rear-wheel steering systems that detects cornering conditions and actively generates a target yaw rate, enabling drivers to maintain turning radius without corrective steering. Cornering is identified using steering angle, angular velocity, curvature, and yaw rate sign with weighted factors. Once detected, the system fixes vehicle speed smoothly and controls yaw rate based on steering angle alone. An optimized rear-wheel control angle is derived using a Sliding Mode Observer and Recursive Least Squares method.

Development of Vehicle Pitch Vibration Reduction Control Using a Band-Stop Filter

Yuma Matsumoto (Toyota Motor)

Vehicle pitch vibration generated when the drivetrain produces driving force poses a ride comfort challenge. This study proposes a control strategy that applies a band-stop filter to the driving force to reduce pitch vibration while minimizing the filter's impact on perceived acceleration. Simulation and real-vehicle verification results are reported.

Basic Study on Vibration and Impact During Vehicle Operation and Transportation: Part 1
-Theoretical Discussion of Impact During Transportation-

Hiroshi Uchida (Trans Quality Research organigation)

Vehicles are used on a variety of roads, surfaces, and in various work sites. Understanding and analyzing vibration and shock during actual driving is important and broad, involving fields such as fracture and reliability, and covers a wide range of fields, from transportation to space and energy, precision electronics, and life sciences. However, there are challenges in measurement, testing, standards and ,application. Previous reports have linked vibration to cargo damping and genetic analysis. This report begins with the discussion of shock.

Integrated Pitch Damping Control Considering Control Device Characteristics for Compatibility of Acceleration Feeling and Ride Comfort

Takuma Takeuchi･Yuma Matsumoto (Toyota Motor)

The increased responsiveness of driving force due to electrification tends to increase pitch speed, which rebels against the feeling of acceleration. Increasing pitch damping can improve the feeling of acceleration, but measures using shock absorbers alone are bad for ride comfort. In this study, we propose integrated pitch damping control that considers the characteristics of the drive actuator and semi-active suspension to achieve both a feeling of acceleration and ride comfort.

Effect of Pitch Damping Moment due to Internal Torque in Propeller Shaft-Type AWD

Shinya Konishi･Shingo Koumura (Toyota Motor)

Analysis of pitch motion in propeller shaft AWD systems in response to road input was conducted using a 5-DOF (Z, q, X, w1, w2) model. Differences in the suspension trajectories of the front and rear wheels generate pitch damping moments due to internal torques. The aforementioned effect was verified both computationally and experimentally, showing that pitch motion is reduced in AWD vehicles compared to 2WD vehicles.

Verification of Driver Delay Time (τ_L) Caused by Human Stimuli Using a Vibrator

Tomoya Kato･Tetsuhiro Okuda (TOYOTA BOSHOKU)

Driving operability is an important performance factor in the domain of vehicle handling. To develop seats that make drivers feel comfortable and contribute to the overall improvement of vehicle performance, various evaluations are being conducted. In this study, we use a vibrator embedded in the seat to provide prior alerts and quantitatively assess the impact on the vehicle's response characteristics by evaluating steering behavior using the first-order delay parameter (τ_L) of the driver model.

Study on Acceleration Noise Reduction Methods by Suppressing Vibration of Cantilever-Supported Heat Shield

Yu Yonai (UD trucks)

This study examined cases in which cantilever-supported heat shield serves as major sources of acceleration noise, resulting in the deterioration of overall noise performance. Modal analysis confirmed that the resonant frequency of the relevant component corresponded with the frequency range responsible for the worsening of acceleration noise. By introducing a sandwich structure to the steel plate component and imparting dynamic vibration absorption performance, it was possible to reduce vibration amplitude even though the resonant frequency itself remained unchanged, thereby successfully suppressing the component's impact as a noise source.

Robust Design and Mechanism Elucidation for Three-Cylinder Engine Idling Vibration Using Machine Learning in Multi-Dimensional Design Space Analysis

Kazuyuki Yamamoto (Secondmind)

Using a machine learning prediction model, we derived robust design specifications that satisfy the idling vibration target of a three-cylinder engine, taking into account the manufacturing variations of key components. Furthermore, by analyzing the correlations between design variables in the visualized multi-dimensional design space, we obtained new engineering insights that contribute to establishing new design guidelines for the three-cylinder engine's idling vibration.

Efficient NVH Integration of EDUs Using Hybrid Dynamic Sub Structuring Approaches

Noriyuki Muramatsu (FEV Japan)･Christoph Steffens (FEV Europe)･Ahmed El-Mahmoudi･Christopher Lechner (FEV Vehicle)

In electric drive unit (EDU) development and vehicle integration, early decisions balancing NVH performance and cost are critical. Assessing NVH behavior in the vehicle context before physical tests is challenging. Using dynamic sub structuring, virtual EDU models can be integrated into measured benchmark vehicles for early acoustic evaluation. Experimental models from databases, including vehicle and mounting concepts, provide essential input for informed design choices. This hybrid approach enables optimization without over-engineering. The paper presents methodological foundations, challenges, and practical applications combining simulation and measurement data, supporting efficient and cost-effective NVH development for electric drives.

Determining Stabilization Parameters in the Inverse Matrix TPA
-Part 1: Validation with Road Noise-

Hiroshi Kashiwazaki･Makoto Takeshita･Zhiqiang Weng･Michio Murase (Ono Sokki)

In the matrix inverse method of Transfer Path Analysis (TPA), a stabilized approximate inverse matrix is often used to suppress the effects of measurement error. However, the optimal parameters for stabilization vary depending on the test object and frequency, and its manual tuning requires time and effort. This presentation reports on the development of an automatic determination method for the stabilization parameter and its validation using suspension inputs of road noise on an actual vehicle.

Method for Determining Measurement Points for Virtual Point Transformation

Makoto Takeshita･Hiroshi Kashiwazaki (Ono Sokki)

In performing Virtual Point Transformation (VPT), it's necessary to consider the stiffness of the mounting locations and the stability of the transformation matrix when determining the measurement positions. However, manually selecting these positions from a large number of combinations is time-consuming and labor-intensive. Therefore, this presentation will introduce an algorithm developed to automatically determine the measurement point locations, and we will confirm its effectiveness through experiments on an actual vehicle.

Development of a Multi-Physics Simultaneous Measurement and Visualization System for Wide-Area and Transient Acoustic Phenomena

Takeo Ban･Yuto Furusawa (DAIHATSU MOTOR)･Osamu Terashima (GIFU UNIVERSITY)･Toya Makino (TOYAMA Prefectural University)･Hiroto Takehara (GIFU UNIVERSITY)

Identifying the factors behind wide-area and transient acoustic phenomena that cause discomfort to vehicle occupants has long been a challenge. In this study, we developed the world's first simultaneous measurement system featuring a 12-channel acoustic probe array. We designed the requirement specifications and commissioned its fabrication to a specialized vendor. This system enabled synchronous measurement of three-dimensional acoustic intensity vectors and airflow velocity within HVAC duct noise. Through coupled data analysis, we quantitatively visualized spatiotemporal noise fluctuations, providing valuable insights into complex acoustic phenomena.

Vehicle Upper Body Structuring Method for Low-Frequency NV phenomena in Early Development Stage Using Component Mode Analysis

Shinichi Kaji･Akihiko Katagiri (Honda R&amo;D)･Moe Hanashima (Estech)･Narikuni Seiya (Honda R&amo;D)

This study proposes a method for developing vehicle body structures to address low-frequency NV phenomena in the early design phase. Component mode analysis is used to define subsystem targets with ranges based on system goals. A CAE model created from early-stage information is employed to evaluate structures before initial drawings are issued, and the results are reflected in the design to improve drawing quality.

Acoustic Detection of Vehicles Outside the Field of View at Intersections
-Identifying Against Oncoming Vehicles-

Masao Ishihama (Ishihamagiken Consulting)･Naoto Hagino (Kanagawa Institute of Technology)

To prevent head-on collisions at intersections, we estimated the capability of a method that uses a microphone array placed across the entire front of a vehicle to selectively detect the main component of tire noise from the intersection corner, which obstructs the field of view, from among the incoming sounds using beamforming and signal processing. As a result, we confirmed the possibility of distinguishing between oncoming vehicles, vehicles passing on intersecting roads, and vehicles approaching from blind spots.

Development of Evaluation Technology for Tire External Noise and Investigation of Generation Mechanism (2nd Report)

Kotaro Mune･Ryuichi Tanimoto (Sekiso)

In our previous report, we presented a mapping of external noise generated by tires and methods to separate the noise radiated from the front and rear wheels. In the present study, we investigated the mechanism by which tire noise spreads outside the vehicle and proposed a countermeasure to confine the noise in the space behind the bumper before it spreads. Using this technique in an actual vehicle test, we improved the sound flow around the tires and successfully reduced external noise.

Analysis of Suspension and Tire Modal Energy Contributions to Whole Structure Resonance

Masato Hashioka･Masashi Komada･Hiroaki Mizuno (Toyota Motor)･Yuichi Matsumura (GIFU UNIVERSITY)

To reduce road noise, it is necessary to clarify the contribution of each subsystem to the whole-system resonance, which is a strong vibration coupling between the tire and suspension. In this study, mode energy contribution analysis is performed on the transfer function of only the tire and suspension coupling points to extract important eigenmodes of each subsystem and understand the mechanism of vibration coupling. Furthermore, guidelines for modifying subsystems to control the blocked force of the whole-system resonance are presented for assigning effective performance targets to subsystems.

A Machine Learning Approach to Estimate Tire Block Force Spectrum for Road Noise Simulation

Yonghun Kim･Taeyoung Kim･Hyunseok Kang (Hankook Tire)

To predict vehicle road noise using the Frequency Based Sub-structuring (FBS) method or to operate a virtual noise simulator, accurate tire block forces are essential. Prior to manufacturing a physical tire, these forces are commonly estimated through finite-element (FE) analysis; however, FE simulations typically require several days, making it difficult to rapidly assess the impact of design modifications on road-noise performance. To overcome this limitation, this study proposes a data-driven modeling framework capable of predicting the tire block-force spectrum directly from design specifications. The methodology, including feature construction, model training, and validation procedures, is described in detail, and the applicability of the proposed approach is demonstrated through prediction results.

Efficient Machine Learning Optimization of Gear Micro Geometry and Comparison with Manually Designed Gears

Andrew Wild･Simon Terry･Paul Langlois (SMT)･Jaekwon Lee･Shinya Sudo (Hino Motors)

Optimisation of gear micro geometry guided by machine-learnt surrogate models is compared to a past engineer-led optimisation and proven to be a highly efficient technique. Subject to engineer-defined objectives, the optimiser identifies high-performing micro geometries with no further human intervention, with all predictions automatically validated by a hybrid Hertzian and FE-based loaded tooth contact analysis. Going beyond the scope of the original manual optimisation, the optimiser is used to identify micro geometries that are torque robust or retain similar performance to the specification without using different micro geometries on the two input gears, thereby theoretically reducing manufacturing costs.

Building a Digital Thread Platform to Enable Bidirectional Design Convergence between Upstream Requirements and Downstream Specifications via MBSE

Seishi Shimamura･Haruhisa Tsuchikawa･Chisato Suzuki･Asami Hozumi･Kiyotaka Shoji･Ryuzo Noguchi･So Nisihwaki･Ryoji Katsuki (Nissan Motor)

This paper reports a digital-thread platform aligned with MBSE that bidirectionally links requirements and component specifications via physics-based models. With SPDM-based unified management and event-driven automated handoffs, it advances automation from requirement updates through analysis/optimization to design finalization and registration. Internal projects showed shorter change-to-result lead time and improved traceability.

A Study on Model Development Guidelines for MBD

Seungjun Back (hyundai motor)

MBD (Model Design Development) is investigated for applying to develop automotive controller. In order to implement MBD in automotive, the development guideline is indispensable. When compared with investigation of the guideline such as MISRA C in C-code, however, the investigation on MBD is currently insufficient. In this paper, we studied the selection of guidelines for the development of MBD of the thermal energy system controller. Comparing MISRA AC SLSF:2023 and MAB 5.0, we selected and applied the guidelines for the development of the thermal energy system controller. Design of data precision is presented for actuator control.

Sound Static Analysis for Safety and Security

Daniel Kaestner･Reinhard Wilhelm･Ferdinand Christian･Adrian Dapprich (AbsInt)

Runtime errors such as buffer overflows or data races are safety- and security-relevant code defects. A sound static analyzer reports all such defects in the code, can prove their absence, and covers further verification objectives such as code guideline checking as well as data and control flow analysis. The analysis can be used to satisfy requirements from norms like ISO 26262, ISO 21434, and from the novel European Cyber Resilience Act (CRA). We will show practical experiments that demonstrate that sound static analysis scales for real-life AUTOSAR integration projects.

Formally Verified Compilation in the Context of Functional Safety

Daniel Kaestner･Bernhard Schommer･Alexander Rogovskyy･Michael Schmidt･Adrian Dapprich (AbsInt)

CompCert is the first commercially available optimizing compiler that is formally verified, using machine-assisted mathematical proofs, to be exempt from miscompilation. The executable code it produces is proved to behave exactly as specified by the semantics of the source C program. This presentation gives an overview of design and proof concept of CompCert, and gives experimental data about performance and size of the generated code on TriCore Aurix. We describe novel contributions to improve the efficiency of the software development and verification process, and discuss the tool qualification strategy with respect to current safety norms.

Model Checking of Automotive Software with CBMC

Shinya Miharu･Wenhung Huang (DENSO)

As automotive software becomes larger and more complex, bugs that are difficult to detect with existing verification processes are increasing. This study focuses on model checking and proposes a method for applying it to the verification process of automotive software. Furthermore, we report the results of evaluating its applicability using internal case studies, as well as future prospects.

Why Model Credibility Isn't Enough:
-Rethinking Trust in Simulation Architectures-

Romain Barbedienne･Boussaad Soualmi･Adeline Lanugue (IRT SystemX)･Julien Silande (Keysight)･Anthony Levillain (OPmobility)･Cedric Leclerc (Renault Group)･Maxime Hayet (Stellantis)･Rim Kaddah･Cristian Maxim (IRT SystemX)

Assessing the credibility of simulation models is crucial, yet models are often integrated within broader simulation architectures. Can the credibility of simulation architectures be derived from their constituent models? This paper explores this question by reviewing state-of-the-art approaches in assembly credibility, including sensitivity analysis, expert qualitative analysis, AI explainability, and network-based methods. Each approach is evaluated according to "rigor", "generalizability", and "resource requirements", highlighting their respective strengths and limitations. The analysis provides insights into the feasibility and challenges of assessing architectural credibility, offering a foundation for future research in this emerging field.

AUTOSAR Activities for Realizing Software Defined Vehicle
-OSS activities for the Middleware-

Masahiro Goto (AUTOSAR)

In the third report, the High-Performance Computer in Vehicle (HPC) and the technologies required for its realization are described. In this report, aiming to provide vehicle use level source code development in AUTOSAR OSS activity called CAPI(Common Adaptive Platform Implementation) and other standardization acvitisies are reported.

Approach to Improve the efficiency of Software Development for Advanced Driver Assistance Systems by Using Continuous Integration (CI)
-(Second Report) Scalability and Test Parallelization using Cloud Computing-

Song Ye･Takuro Yuhara･Tomonori Nambu (Nissan Motor)

A cloud-based CI for automotive software was constructed by leveraging cloud scalability to optimize cost and time. By integrating auto-scaling runners and test parallelization using Serverless functions, software development efficiency was improved, enabling timely releases and continuous quality maintenance. This paper describes the architecture of the cloud CI and its demonstrated effects.

Flexible Automotive Software Architecture utilizing Container Orchestration and PCIe

Lukas Stahlbock･Jan Weber･Emrecan Cetin･Takuya Nigoro･Ise Shingo (IAV)

The automotive industry is undergoing a significant transformation towards Software Defined Vehicles (SDVs), necessitating a flexible system architecture. Container orchestration emerges as a promising solution for managing software in distributed systems, allowing for the full utilization of service-oriented architectures (SOA). Additionally, PCIe facilitates efficient data transfer across host borders, achieving higher data rates than Ethernet-based systems while simultaneously reducing CPU overhead. Integrating container orchestration within SOA and utilizing PCIe enables portable software solutions without network constraints. This study evaluates the application of containers and PCIe in modern SDV architectures, aiming to enhance flexibility and efficiency in software integration and management.

Improving Continuous Development Efficiency Along the Full Project Lifecycle
-The CODE4EV Framework for Software Defined Vehicles-

Eric Armengaud (Armengaud Innovate)･Bogdan Kowalczyk (APTIV Technical Center)･Jose Manuel Rodriguez (Instituto Tecnologico de Aragon)･Valentin Ivanov (Technische Universitaet Ilmenau)･Benedikt Lindner-Rabl (BET-MOTORS)･Walter Lhomme (University of Lille)･Andrea Luzzana (FAE Technology s.p.a.)･Tomaz Kompara (Elaphe Propulsion Technologies)･Miguel Barcelona (Instituto Tecnologico de Aragon)

The Software-Defined Vehicle paradigm is disrupting the automotive domain by introducing DevOps processes in a product-oriented industry. In this context, the European project CODE4EV targets to accelerate vehicle development by establishing a collaborative development framework addressing the entire lifecycle and aiming at improving efficiency, safety, and scalability across vehicle categories. A distinctive feature is its support for distributed testing in an agent based setup to lever geographically dispersed partners and lab infrastructures. Target of this paper is to introduce the framework along the three automotive industrial use cases, and deployed for passenger cars, two-wheelers and heavy-duty trucks.

Legacy Meets Future: SOA Migration and Signal-to-Service Integration for Automotive HPCs

Jyotsana Singh･Piyush Burangi･Rital Surana･Arshiya Shaikh･Uzeena Mhaskar (FEV India Pvt)･Pravinjoelraj Victorsam･Masato Ugaki (FEV)

Software-Defined Vehicles (SDVs) drive a shift from hardware-centric systems to flexible, connected platforms powered by Service-Oriented Architecture (SOA). However, Legacy Electronic Control Units (ECUs) with signal-based communication pose challenges in transitioning to SDV-ready E/E architectures. To overcome these challenges, this paper introduces a unified modernization strategy that combines SOA migration workflows with a Signal-to-Service (S2S) translation framework, enabling seamless coexistence between legacy ECUs and next-generation High-Performance Computing (HPC) platforms. For cases where direct migration is not feasible, a scalable S2S gateway translates CAN signals to Ethernet service interfaces, ensuring interoperability across domains while meeting automotive-grade latency, safety, and security requirements.

A Semantics-Preserving Master Scheduler for Mixed-Criticality Control in Lingua Franca

Yutaka Matsubara (Nagoya University)･Wenhung Kevin Huang･Akihito Iwai (DENSO)

We designed and evaluated a scheduler for a container-based consolidated ECU that guarantees deterministic process execution order in a mixed environment of Lingua Franca–compliant real-time applications and non-LF applications.

Software Updates as Enabler for Cyber Security in the CV Domain
-From Regulations to Processes to a One-Stop System Solution-

Alexander Roy･Gila-Marie Achenbach (IAV)･Dennis Kengo Oka (IAV)

Increasing digitalization in commercial vehicles makes cybersecurity and software updates critical. Secure update mechanisms are essential for compliance as regulations tighten. While major OEMs have implemented Software Update Management Systems (SUMS), smaller companies face challenges as exemptions end. Regulations require automated, traceable processes beyond manual updates. SUMS offers a holistic approach, including version control, approval workflows, and risk assessment. IAV's modular, cloud-based SUMS enables OEMs and suppliers to deliver secure, scalable updates and integrate seamlessly into existing environments—reducing complexity and accelerating deployment.

Development of Prediction Method for Aerodynamics Noise Generated Inside Tailgate Gap Sections

Yuta Ito (Toyota Motor)･Satoru Yamada (Dassault Systemes)･Ayumu Saita (Toyota Motor)･Lorenzo Prati (Dassault Systemes Singapore Pte)･Shirou Yasuoka (Toyota Motor)

Quietness is an important aspect of a vehicle's commercial appeal, and noise reduction has become one of the major development objectives. In recent years, with the spread of electrified vehicles such as HEVs and BEVs, the contribution of engine noise has diminished or even become negligible. Furthermore, advances in vibration and noise reduction technologies have lowered road noise and motor noise, resulting in the relative increase in the contribution of aerodynamic noise during high-speed driving. Aerodynamic noise is caused by pressure fluctuations around the vehicle's shape and groove sections. The ability to evaluate these factors at the early stages of design is extremely important for automobile manufacturers, and prediction methods for aerodynamic noise generated by vehicle shapes have been developed thus far. In this presentation, we report on the development of a prediction method for aerodynamic noise generated inside the backdoor groove section, using numerical fluid analysis based on the Lattice Boltzmann Method (LBM), along with correlation results between simulations and actual measurements.

Prediction of Aerodynamic Noise from Cooling Fans in Automotive ECUs using Acoustic Analogy

Yuichiro Konishi･Yosuke Soeda･Masanori Yokota (Panasonic Automotive Systems)

In the development of in-vehicle infotainment Electronic Control Units (ECUs), air-cooling solutions are required to address thermal and acoustic challenges due to increasing vehicle intelligence and electrification. To improve noise control strategies, this study introduces Computational Fluid Dynamics (CFD) combined with an acoustic analogy approach to predict aerodynamic noise generated by ECU cooling fans. The effectiveness of the proposed method is verified by comparing simulation results with experimental noise measurements for different fan usage cases.

Application of Aerodynamic Surrogate Models in Actual Development

Kohei Seo･Keigo Shimizu･Yusuke Nakamura･Takenori Hiraoka･Akihiro Nakata (Mazda)･Takuji Nakashima (Hiroshima University)

We have developed an aerodynamic surrogate model capable of rapidly outputting 3D flow fields for vehicle shapes to achieve a significant reduction in the aerodynamic evaluation period. Furthermore, we have combined it with an evaluation method that utilizes Local drag, which divides the flow field into three components to facilitate the practical application in actual development processes.

Study of Boundary Conditions in CFD Analysis of Brake Disc

Shigenori Fujisawa･Tsutomu Nagashima･Toshiki Hotta･Shinichi Morita (Advics)

The cooling performance of brake disc is influenced by the vehicle in which they are installed and by surrounding components. When predicting actual performance using CFD analysis, it is necessary to consider the boundary conditions that reflect installation on a real vehicle. However, these boundary conditions are not well known. Therefore, we studied the boundary conditions by measuring on the vehicle and performing CFD analysis using a vehicle model.

Preliminary Demonstration of the Early-Stage Detection of Lithium Plating for Cell Blocks based on Charge Curve Analysis Data

Kenichiroh Koshika (NTSEL)･Hideki Tsuruga (JET)･Tomokazu Morita (TOSHIBA)･Keizoh Honda (JET)

A method for detecting the early stage of lithium plating within cell blocks was investigated using charge curve analysis. The early stage of lithium plating was estimated based on the charge curve analysis data, such as, negative electrode capacity and Shift of operating window (SOW) capacity. Disassembly inspections of the negative electrode and thermal runaway tests on cells were conducted to confirm the early stage of lithium plating within cell blocks.

Demonstrating the Influence of Lithium Plating on Thermal Propagation and Lithium Plating Occurring in Mechanically Constrained Cells

Keizoh Honda･Hideki Tsuruga (JET)･Tomokazu Morita (TOSHIBA)･Kenichiroh Koshika (NTSEL)

Two laboratory-level tests were conducted to reveal the impact of lithium plating on thermal propagation and to demonstrate that mechanical constraint for a cell causes lithium plating within cells. In a thermal propagation test, thermal runaway propagated to an adjacent cell with lithium plating in a shorter period than to an adjacent cell without lithium plating. Compared to unconstrained cells, constrained cells exhibited capacity degradation after fewer charge-discharge cycles and caused lithium plating on the negative electrode.

Physics Informed State Estimation Technology for Battery Storage System

Hiroki Nagano･Tenyu Yan･Akira Shoji (Mazda)･Takashi Utsunomiya･Yasuhiro Makino･Shin Wakitani･Toru Yamamoto (Hiroshima University)

In order to enhance the value of electric vehicles and contribute to carbon neutrality and power stabilization, we are developing control technology that can extend the lifespan of battery systems. This paper reports on state estimation technology in battery systems, in which physical model information of the battery is incorporated into equivalent circuit models, enabling high-accuracy estimation of internal states even under degradation.

Battery Development for third-generation New EV

Hanae Tsurita･Sadahiro Nagasaka･Ryo Sakamoto･Kenji Hosaka･Norihiko Hirata (Nissan Motor)

The new EV has developed a technological strategy aimed at the full-scale adoption of EVs, focusing on balancing optimal capacity and high efficiency. By leveraging Big Data analysis based on market requirement assessments, the strategy includes capacity optimization, an Intelligent Route Planner (IRP) capable of highly accurate predictions of arrival times and remaining SOC, and integrated thermal management to improve energy efficiency and charging performance. This combination achieves a high-level balance among performance, cost, and convenience.

Efficiency for Rightsizing:
-Considerations on how to Tackle the Battery Capacity Competition of Electric Vehicles-

Marc Sens･Alexander Fandakov･Oliver Nolte･Adalbert Wolany (IAV)･Christoph Koehler (IAV)

Battery size is crucial for electric vehicles, affecting range and cost. The article explores technologies to reduce battery size and cost, avoiding the race for larger batteries. It assesses the impact of charging infrastructure and high-performance charging on battery capacity. Efficiency considerations, such as thermal management and using waste energy, are evaluated to reduce electrical consumption. Additionally, the influence of new battery chemistries and technologies on energy consumption and fast charging cycles is discussed. The goal is to find solutions that optimize battery use without compromising vehicle performance or increasing costs.

SOP Accelerator for Battery Development with Smart Testing Approach

Johannes Werfel･Maria Kalogirou･Markus Straesser･Joerg Mueller･Matija Bogdanic･Mirko Leesch (IAV)

The presentation introduces a new development method at IAV using enhanced battery simulation throughout the V-process. It comprehensively models physicochemical aspects of battery cells, including thermoelectric and mechanical properties of the batteries and their modules. This allows early analytical evaluation of layouts during concept development. Aging predictions optimize mechanics of battery and cells to meet lifetime requirements, reducing validation efforts through simulation-based decision-making. The method achieves significant savings of 20-30% across the development process, with potential for further improvement. This methodology approach has been used and validated during different development projects and sample phases successfully.

A Coupled Thermal-Electrical Model for Lithium-Ion Battery Thermal Runaway with Gas Generation and Venting Dynamics

Andreas Podias･Subhajeet Rath･Steven Wilkins (TNO Netherlands Organisation for Applied Scientific Research, Mobility & Built Environment Unit, Powertrains Department)

In this work a comprehensive, experimentally validated, model is developed to simulate thermal runaway (TR) and venting in lithium-ion pouch cells, with NMC-based cathode, where TR is initiated by external heating. It is based on a coupled electrical-thermal previous model that included the initial energy input, the chemical decomposition processes of the anode, cathode and the electrical energy released by an internal short circuit and currently extended to include gas generation, internal pressure and venting dynamics. The model captures key features of TR, such as temperature evolution and temperature change rate, internal pressure changes and venting. Its findings are expected to support the foundation for future research dedicated on improving battery safety.

Development of New Motor for High Powered Plug-in Hybrid Vehicle

Ryohei Hirota･Daisuke Kitada･Shinji Oita･Hiroki Kato･Suguru Gangi･Hajime Ukaji･Akihide Shimmei (Toyota Motor)

CAFE and emissions regulations have been strengthened year by year, and the widespread adoption of clean vehicles with low CO2 emissions is highly anticipated. To meet the diverse needs of customers, Toyota has developed a new motor for plug-in hybrid vehicles (PHEVs). This report covers the development of the sixth-generation motor for the new RAV4, which aims for high output while achieving reduced losses, compactness, and lightweight by revising the stator structure, electromagnetic circuit, and cooling system.

Next Gen EDU with innovative Electric Motor and Inverter Technologies Development

Jan Nowack･Daniel Butterweck･Shady Nada･Christoph Neuhaus･Michael Schroeder (FEV Europe)･Yasutaka Ikawa (FEV Japan)

The article gives an overview of the status, Innovations and targets of the EU funded Project HiVEP – High-Voltage Fast-Charging Efficient Electric Vehicle Powertrains, a post 800 Volt electric powertrain architecture for mass EV markets. The key innovations are a Modular Multi-Level-Inverter using SiC Wide-Band semiconductors, Rare-earth-free IPMSM Machine with active winding reconfiguration, integrated I-Charger, high C-rate battery with advanced BMS and ‘explainable AI' control, holistic thermal management and Digital twin-based optimization. The development targets are ultra-fast Charging times, 25% efficiency gain, 20% cost reduction and 21% range increase for same battery weight compared to current state of the art powertrains.

Development of a Loss Measurement Method for Each Component of the Electric Powertrain under In-Vehicle Conditions

Jumpei Kobori･Nobunori Kita･Hiroshi Yamazaki･Yasuyuki Okada･Tomoko Numata (HORIBA TECHNO SERVICE, Co., Ltd)

Although loss measurement of each EV powertrain component on a motor bench is possible, calculating losses under actual operating conditions is difficult due to various vehicle factors. In this study, we developed a method to directly measure the losses of each component (converter, inverter, motor + gearbox, etc.) of EV powertrain under in‑vehicle conditions. We report the loss distribution under WLTP conditions, as well as the challenges identified for future work.

Model Development for Thermal Simulation of Electromechanical Integrated Electric Water Pump

Yasutaka Aoyama (AISIN)

The electric water pump consists of ECU, motor, and pump, and heat is generated and dissipated in these three components, resulting in complex heat flows. In this case, we will introduce the development of a thermal simulation model, which serves as a digital tool for the thermal design of integrated electromechanical ECU.

Reduction of Harmonic Current Flow into DC Link Capacitors via Rectifiers in Series Hybrid Vehicles

Aira Katayama･Haruka Tominaga･Keiichiro Kondo (Waseda University)･Shun Taniguchi･Shigehisa Aoyagi (Astemo Corporation)

In a series hybrid system, performing pulse-mode switching on the drive motor side causes harmonic currents to flow into the DC link capacitor. To mitigate these harmonics, harmonic superposition is applied via the switching control of the rectifier (generator-side inverter), thereby reducing the harmonic currents flowing into the DC link capacitor.

Electromagnetic Vibration and Noise Analysis of PMSM by Coupling Electromagnetic Field and Structure

Yuya Watanabe･Tatsuki Yamada (Honda Motor)･Masayuki Ryokata (AUTO TECHNIC JAPAN)

Focusing on a permanent magnet synchronous motor, the electromagnetic excitation force calculated through electromagnetic field analysis was input into a structural analysis model of the stator, and a method for analyzing stator vibrations that occur during product operation was studied. The electromagnetic excitation force was decomposed into spatial and time orders, and the vibration response of the time order was calculated by tracking the speed change of the motor, and the results were compared with the experimental results.

Development of a New Power Control Unit Built Into e-Axle For the 6th. Generation Plug-in Hybrid System

Satoshi Yasuda･Keisuke Yuki･Syuhei Hisada (TOYOTA Motor Coporation)･Shingo Miyamoto･Kunihiro Suzuki･Tomohiko Sato･Keita Hayashi (DENSO)･Naoya Odashima (TOYOTA Motor Coporation)

To achieve carbon neutrality, it is essential to develop vehicles with diverse powertrains tailored to the needs of customers in each region. At TOYOTA, we refer to this approach as the 'Multi-path way approach.' In this paper, we introduced that we have developed a new power control unit built into the e-Axle for the 6th generation plug-in hybrid system. Additionally, for the first time, we have applied SiC semiconductors to the power control unit in the Toyota Hybrid System (THS), and we will introduce the purpose and benefits of this application.

Development of High-Productivity Manufacturing Technology for Fuel Cell Separators Using Carbon-Based Resin Composites

Kenichi Kondo･Takamasa Kanie･Masayuki Kokubun･Tadatoshi Sugiura (TOYOTA AUTO BODY)

As fuel cells become more widespread, there is a demand for high-precision, high-speed molding of separators. Carbon resin composites are expected to be lightweight and highly durable for a wide variety of applications. However, productivity is poor because heating and cooling are required for molding. In this study, we aim to achieve a molding cycle with carbon resin composites equivalent to that of metal materials.

Effect of the Cathode Carbon Structure and the Distribution of Pt and Ionomer on Improving the performance and Durability of Polymer Electrolyte Fuel Lls

Makoto Uchida (University of Yamanashi)

We report the effect of platinum and ionomer distribution in cathode catalysts with different carbon structures on the performance and durability of solid polymer electrolyte fuel cells. In particular, we discuss the effect of generated water on the adsorption state of ionomer on the Pt surface, and the impact of ionomer poisoning, which has been a problem in the past.

Activities of the PEFC Evaluation and Analysis Platform initiative
-NEDO innovative FC-MEA evaluation and Analysis-

Masaki Yamauchi･Norimitsu Takeuchi･Kazuhiko Shinohara･Hideto Imai (FC-Cubic)

We strengthened cooperation between industry, academia, and governmental parties and built the "PEFC Evaluation and Analysis Platform (PEFC-PF)" to evaluate fuel Cell materials. This PEFC-PF promoted collaboration between the materials research group of the Innovative FC Project and the platform groups. Improving the properties of materials and components is essential to achieving the 2030 targets. In particular, the "NEDO Innovative FC MEA," which combines each element that makes up the MEA (membrane electrode assembly), showed the achievement status and identified issues that arise when combining them and issues for high-temperature operation that are expected in the future.

Effect of catalyst layer and electrolyte membrane on high temperature and low humidity operation of PEFC

Sana Kawashita･Hiroyuki Kanesaka･Hiroki Kusakabe･Chunyan Li (FC-Cubic)

High-temperature, low-humidity operation was conducted at 120°C and 40% RH to investigate the effects on the catalyst layer and electrolyte membrane. It was found that in high-temperature environments, the softening of the electrolyte membrane can easily degrade its mechanical properties, potentially causing rapid membrane deterioration. Furthermore, continuous high-temperature operation was suggested to accelerate catalyst layer degradation, potentially leading to voltage drop.

Sensitivity Assessment of Fracture-Controlling Factors under High-Pressure Hydrogen
-Using the C-FaTH₂ Next-Generation Testing System and an Orthogonal Experimental Design-

Hirotada Fujiwara･Hiroaki Kondo･Tomohiro Shimada･Kazumi Nakayama･Takahiro Miyamoto (Chemicals Evaluation and Research Institute, Japan)

A dedicated facility (C-FaTH₂) and an advanced testing system capable of continuously reproducing high-pressure hydrogen pressurization–depressurization cycles for over 24 hours, faithfully simulating operational protocols, were established. This infrastructure enables long-term degradation assessments that were previously unattainable. In this study, an orthogonal experimental design was employed to systematically elucidate the protocol sensitivity of fracture-controlling factors governing the degradation behavior of polymer materials under high-pressure hydrogen exposure.

[Keynote Address] Concept of Energy-Efficient Vehicle Operation under Time Constraints and Speed Limits

Takafumi Koseki･Xuanlang Meng (The University of Tokyo)

The authors have mainly researched energy-saving operations for electric railways, particularly utilizing regenerative braking. This concept shares similarities with energy-saving operations for electric vehicles (EVs) with in-motion charging. This paper introduces the latest research achievements, focusing on extracting patterns from computationally intensive mathematical optimization results, such as dynamic programming. The research aims to efficiently determine energy-saving operation curves even under complex speed restrictions. Furthermore, the paper discusses the similarities and differences when considering EV energy-saving operations.

Development of a Vehicle Technology Choice Model Considering Critical Minerals

Atsuo Komatsubara･Tomoki Nishi (Toyota Central R&D Labs.)

This study develops a vehicle technology choice model that explicitly represents price–demand feedbacks for critical minerals (lithium, nickel, and cobalt). Results showed that, under the assumed scenarios, the diffusion of battery electric vehicles increased mineral demand and prices, which in turn hindered further penetration. We also evaluated mitigation strategies, including battery recycling, second-life use, and a shift toward low-cobalt cathodes.

Synergistic Effects of Hybrid Electric Vehicle Conversion for Heavy-Duty Trucks and Dynamic Power Supply on Highways

Yoshihisa Hojo (Toyo Denki Seizo)

This paper discusses the energy-saving effects achieved by converting heavy-duty trucks to hybrid electric vehicles (HEVs) and installing power supply equipment on grade sections for dynamic power supply and regenerative braking. Additionally, it demonstrates a method for converting existing heavy-duty trucks with internal combustion engines into hybrid electric vehicles (HEVs) using in-wheel motors.

Performance Diagnosis Method for Vehicle-Mounted PV Panels

Hidenori Mizuno･Toshimitsu Mochizuki･Kenji Kamide･Katsuto Tanahashi･Takashi Oozeki (AIST)

When vehicle-integrated photovoltaic (PV) power generation systems become widespread in the future, it will be essential to perform simple performance evaluations to detect malfunctions in the installed PV panels, assess their degradation levels, and estimate replacement timing. We are developing such methods using our own PV-equipped electric vehicles.

Wireless Charging for Electric Road Vehicles: Challenges and Opportunities in Standards, Technology, and Energy Management

Steven Wilkins･Subhajeet Rath･Jan-Willem Sangers･Paul Mentink･Frank Willems (TNO)

Wireless charging (wireless power transfer, WPT) for electric road vehicles is moving from prototypes toward pilots and early products, motivated by convenience, automation readiness, and the potential to reduce battery size through opportunity charging and dynamic wireless power transfer (DWPT). This paper reviews key challenges and opportunities for static and dynamic WPT, focusing on interoperability and standardization (IEC 61980 family, SAE J2954, ISO 15118), core technologies (magnetic couplers, power electronics, alignment, safety sensing, EMC and EMF), and enabling energy management from vehicle to grid and fleet levels. We highlight where standards already provide a foundation and where gaps remain for scalable deployment, especially for DWPT and heavy duty applications.

Power Supply Technologies for Battery-Powered Trains

Hiroshi Yoda (Railway Technical Research Institute)

The deployment of battery-powered trains is expanding worldwide as a promising solution to accelerate decarbonization in non-electrified lines. This presentation provides an overview of the contact-based charging systems currently in commercial operation and introduces the development progress of wireless power transfer (WPT) technologies.

Development of a Solar Irradiance Estimation Method for Onboard PV Systems

Shuai Pei･Masaaki Yanagi･Toshio Hirota･Yushi Kamiya (Waseda University)

Due to shading from buildings and trees, solar irradiance received by onboard PV systems is lower than that of stationary PV systems. This study measured vehicle and fix-point irradiance under sunny and cloudy weather across various urban, suburban, and expressway routes. The measured data was analyzed to clarify how these diverse driving and weather conditions specifically influence the ratio between vehicle and fixed-point irradiance (V/F). Furthermore, a practical method for estimating vehicle irradiance was constructed with the insights obtained from this analysis.

Transition of Model-Based Development Technology Technical Committee based on International Standard Description

Junichi Ichihara (AZAPA)

In this committee, we have discussed the distribution of models between OEMs and Tier 1, as well as between Tier 1 and Tier 2, based on the keywords of 'electricity' and 'heat,' while utilizing a model language described by international standards. We will now present the current transitions and an overview of our ongoing activities.

Application of Description Models Based on the International Standard Language VHDL-AMS to Digital Validation

Toshiji Kato (Doshisha University)･Kimitoshi Tsuji (Digital Twins)･Tsunehiro Saito (AGC)･Masahiro Okamura (JSOL)

This paper introduces and provides an overview of model descriptions using VHDL-AMS for digital validation.

Initiatives for Virtual Testing Using Digital Twins and Digital Authentication III
-Comprehensive CO₂ Reduction and New Manufacturing System-

Kimitoshi Tsuji (Digital Twins)･Tosiji Kato (Doshisha University)･Tsunehiro Saito (AGC)･Masahiro Okamura (JSOL, INC.)

In manufacturing, certification through actual testing has limitations due to the lack of reproducibility and the diversity of conditions. Therefore, this paper introduces an initiative aimed at certification through virtual testing, using a full-vehicle model of an EV as a tool for digital certification, which can be applied to off-cycle credits that will be implemented in 2030 and can also be used for vehicle performance development.

Study and Proposal on OCC for Automotive Glass Using EV Model (Third Report)
-POC of Digital Authentication Protocol with EV Cabin Thermal Model - Part 2-

Tsunehiro Saito (AGC)･Masahiro Okamura (JSOL)･Kimitoshi Tsuji (Digital Twins)･Toshiji Kato (Doshisha University)

OCC (Off-Cycle Credit) is the important CO2 credit regulation. In the first and second reports, we reported the results of the OCC study using the EV cabin thermal model and the simulation of annual CO2 emissions from EV. In the third report, we compare the calculation method of the US OCC with the EV cabin thermal model.

A Study on Implementing Model Traceability with Cryptographic Hash Functions

Masahiro Okamura (JSOL)･Kimitoshi Tsuji (Digital Twins)･Toshiji Kato (Doshisha University)･Tsunehiro Saito (AGC)

In recent years, test requirements have become increasingly complex, making it difficult to evaluate performance through physical testing alone, and simulation-based evaluation has gained attention. This paper introduces a traceability approach that uses cryptographic hash functions to ensure the authenticity of simulation models, and also presents verification results obtained in a simplified demonstration environment.

Verification on the Effectiveness of ELectro-Mechanical Coupled 1D Models for Vehicle System Analysis and ECU Circuit Analysis
-Operation of an in-Vehicle Electromagnetic Solenoid Actuator and its Control Circuit Under Low Voltage Condition of Vehicle Battery-

Keita Inoue (DENSO)･Masanari Ueda (Siemence Electronics Design Automation Japan)･Yoshiko Ikeda (Toshiba Electronics Devices & Storage)･Takao Egami (AC Technologies)･Makoto Yamatani (CHINO GIKEN)･Daisaku Mukaiyama (RUBYCON)･Yoshinori Aruga (KOA)･Kota Saito (Murata Manufacturing)･Masashi Inaba･Takuya Shinoda (DENSO)

To meet the increasing demand for shorter Automotive-ECU development cycles in recent years, the realization of MBD (Model-Based Development) requires a variety of analyses, including system-level, circuit-level, and thermal analyses. While the effectiveness of an electro-mechanical coupled 1D model of an in-vehicle electromagnetic actuator, which is sharing among industry partners (OEM, Tier 1, and Tier 2), has already been validated in circuit analysis, this study verifies its effectiveness in vehicle system-level analysis linked with ECU circuit analysis.

Conduction Noise Analysis of High-Precision IC and MOSFET Models Using Electro-Mechanical Coupled Simulation

Yoshiko Ikeda (Toshiba Electronic Devices & Storage)･Takao Egami (AC Technologies Co., LTD.)･Takashi Nakanishi (Toshiba Electronic Devices & Storage)･Masashi Inaba･Keita Inoue･Kazunari Hahimoto (DENSO)･Masanari Ueda (Siemens Electronic Design Automation Japan K.K.)･Daisaku Mukaiyama (Rubycon Corporation)･Yoshinori Aruga (Koa)･Takuya Shinoda (DENSO)

With the increasing functionality of automotive systems, the higher density, faster operation, and greater power of electronic control units have intensified challenges related to EMI (Electromagnetic Interference) and EMS (Electromagnetic Susceptibility). In this study, high-precision IC and MOSFET models developed last year were utilized to verify transient electrical and thermal responses on actuator boards within a collaborative research project. This year, we focus on applying these models to conduction noise analysis, aiming to establish an analytical approach that contributes to improving the reliability of automotive electronic systems.

A Modeling Study of Aluminum Electrolytic Capacitors Considering Lifetime Degradation

Daisaku Mukaiyama (Rubycon)･Masashi Inaba (DENSO)･Masanari Ueda (Siemens)･Yoshinori Aruga (KOA)･Yoshiko Ikeda (Toshiba Device and Storage)･Takao Egami (AC Technologies)･Kazunari Hashimoto (DENSO)･Hideki Jounokuchi (Nagoya Institute of Technology)･Masayoshi Yamamoto (Nagoya University)･Takuya Shinoda (DENSO)

We have been studying a multi-domain electrical and thermal model for aluminum electrolytic capacitors. Using a boost chopper as an example, we have evaluated the validity of the electrical characteristics model at low temperatures through simulations and actual measurements, achieving a certain level of results. In this work, we further examined the impact of lifetime degradation of aluminum electrolytic capacitors on impedance, and we report on these findings.

Effect of a Simulation Model Considering Dynamic Characteristics of Power Inductors on DC-DC Converter Performance

Kazuhiro Ito･Jianxin Sheng (Murata Manufacturing)･Masashi Inaba･Keita Inoue (DENSO)･Masanari Ueda (Siemens Electronic Design Automation Japan)･Daisaku Mukaiyama (RUBYCON)･Yoshinori Aruga (KOA)･Yoshiko Ikeda (Toshiba Electronic Devices & Storage)･Takao Egami (AC Technologies)･Takuya Shinoda (DENSO)

This study evaluates the impact of condition settings on DC-DC converter characteristics using a simulation model that incorporates temperature, AC amplitude, and DC bias dependencies of power inductors, and demonstrates its effectiveness in improving simulation accuracy.

Resistor and PCB Modeling and Validation for Tier 1 and Tier 2 Collaboration Using MBD

Yoshinori Aruga (Koa)･Masashi Inaba･Keita Inoue (DENSO)･Masanari Ueda (Siemens Electronic Design Automation Japan K.K.)･Daisaku Mukaiyama (RUBYCON CORPORATION)･Haruki Takei (Siemens)･Takao Egami (AC Technologies Co., LTD.)･Yoshiko Ikeda (Toshiba Electronic Devices & Storage)･Hideki Jounokuchi (Nagoya Institute of Technology)･Takuya Shinoda (DENSO)

In the thermal design of in-vehicle electrical equipment that is becoming smaller and more sophisticated, it is important to consider not only semiconductors but also the small components (R, C, etc.) in their peripheral circuits. In this report, a 1D model (coupled mechanical, electrical circuit, and thermal model) of an actuator drive circuit shared by WG members consisting of Tier1 and Tier2 is discussed. Furthermore, we discuss the modeling of resistors and substrates, along with their validation experiments.

Verification of Circuit Parameter Optimization Technology for ECU through Inter-company Collaboration Using an Electro-mechanical Coupled 1D Model

Masashi Inaba (DENSO)･Hiroki Nakamizo (Institute of Science Tokyo)･Masaki Ueda (SIEMENS EDA Japan)･Takao Egami (AC Technologies)･Yoshiko Ikeda (Toshiba Electronic Devices & Storage)･Daisaku Mukaiyama (Rubycon)･Yoshinori Aruga (KOA)･Kota Saito (Murata Manufacturing)･Wataru Hijikata･Hideaki Fujita (Institute of Science Tokyo)

Recently, the demand for shorter ECU development cycles has increased, drawing attention to electromechanical coupled 1D modeling. Last year, using a model shared among companies, we analyzed actuator drive circuit behavior and simulated ECU heat generation, then fabricated an actual board to verify consistency between experimental and simulation results. This year, we investigate the application of this approach to circuit parameter optimization.

High Precision 3D Thermal Analysis of Printed Circuit Board Components using Transient Heat Generation obtained from Circuit Simulation

Haruki Takei (Siemens)･Nakaomi Sawada (PERSOL CROSS TECHNOLOGY CO., LTD.)･Minoru Shibutani (Kozo Keikaku Engineering)･Masanari Ueda (Siemens Electronic Design Automation Japan K.K.)･Yoshiko Ikeda (Toshiba Electronic Devices & Storage Corporation)･Ryuta Yasui･Osamu Seya (Institute of Scienece Tokyo)･Kazunari Hashimoto･Keita Inoue･Takuya Shinoda (DENSO)

The Electronic Components and Thermal Design Working Group has been investigating the digitalization of the board design process as a contributory research project since 2024. In this presentation, we will report on our attempt to apply 3D thermal fluid simulation to the board design process.

Minimization of Discrepancy between Measurement and Thermal Fluid Analysis for ECUs Using Inverse Analysis

Minoru Shibutnai (Kozo Keikaku Engineering)･Ryuta Yasui (Institute of Science Tokyo)･Haruki Takei (Siemens)･Masanari Ueda (Siemens Electronic Design Automation Japan)･Yoshiko Ikeda (Toshiba Electronic Device & Storage)･Osamu Seya (Institute of Science Tokyo)･Kazunari Hashimoto･Keita Inoue･Takuya Shinoda (DENSO)

As part of the coupled circuit–thermal simulation initiative, we validate the accuracy of 3D thermal–fluid simulation using heat generation calculated from circuit simulations. Based on the results, we propose a process and technical guidelines to improve both simulation and experimental accuracy, thereby reducing discrepancies and enhancing thermal design reliability.

Verification of Surrogate Modeling and Optimization Design of ECU Heat Radiation Structure by Using MBD

Kazunari Hashimoto (DENSO)･Ryuta Yasui (Institute of Science Tokyo)･Masashi Inaba (DENSO)･Haruki Takei (Siemens)･Minoru Shibutani (Kozo Keikaku Engineering)･Masanari Ueda (Siemens Electronic Design Automation Japan)･Yoshiko Ikeda (Toshiba Electronic Devices & Storage)･Daisaku Mukaiyama (RUBYCON)･Kazuyoshi Fushinobu (Institute of Science Tokyo)･Takuya Shinoda (DENSO)

Acceleration of technological innovation is expected to shorten the development period by using CAE. Last year, we made an actual ECU that matched the actuator drive circuit model shared among companies and verified the accuracy of the thermal analysis model that matched the actual ECU. This year, we will verify the consistency between the analysis results of the optimized heat radiation structure design for the actual ECU and the corresponding experimental results.

Automotive Engineering-Centric Agentic AI Workflow Framework

Tong Duy Son･Zhihao Liu･Piero Brigida･Yerlan Akhmetov･Gurudevan Devarajan･Kai Liu･Ajinkya Bhave (Siemens Digital Industries Software)

AI Agents based on foundation models have potential to support automotive engineers in model-based design development. We present an industrial Copilot ecosystem with orchestrator and specialized agents managing complex automotive tasks. Engineers specify design requirements; agents coordinate 1D-3D simulations, CFD, ROM AI models, and design exploration tools. Moreover, AI agents could leverage historical data, requirements, codes, simulation configurations and test data analysis scripts. Our technologies enhance trustworthiness through engineer-centric design with feedback loops. Results demonstrate faster workflows, seamless integration across CAD-CFD tools, optimization, and human-AI collaboration for automotive applications.

Study of Achievement Both Noise and Vibration and Thermal Efficiency by Using the Excitation Force of a Piston System

Hironao Sato･Masahiro Oba･Takashi Hiromoto･Kiyofumi Sato･Toshiyuki Sonobe･Noriaki Sekine (SUBARU)･Yasuo Moriyoshi･Koji Morikawa･Tatsuya Kuboyama (Chiba University)

Rapid combustion is being attempted as a means of improving thermal efficiency of internal combustion engines, but rapid combustion deteriorates the vehicle interior noise level. This study focused on the piston system as a phenomenon of noise and vibration caused by combustion. The results of a study to achieve both noise and vibration and thermal efficiency at various engine speed and load by using the excitation force indicators of the piston system are reported.

High-Speed Imaging and Numerical Analysis of Spark Discharge for Combustion Prediction in Spark-Ignition Engines

Ryo Muto (SUBARU)･Tatsuya Kuboyama･Yasuo Moriyoshi (Chiba University)

Accurate analysis of spark discharge behavior, which influences initial flame formation, is essential for improving the prediction accuracy of spark-ignition engine combustion. In this study, high-speed imaging of the spark discharge process was conducted using a fan-equipped constant-volume chamber to investigate the effects of ambient pressure and flow velocity. Furthermore, the method for setting model constants based on experimental data was examined, and the validity of numerical analysis was evaluated.

Effect of RON and Cycle-to-Cycle Variation on Knocking Phenomena

Taisei Shimizu･Yuki Imagawa･Shota Okuyama･Kazunari Kuwahara (Osaka Institute of Technology)

When intense knock occurs in spark-ignition engines, the main combustion decelerates immediately before unburned-zone autoignition. It has been considered that the deceleration is caused by the interaction between flame propagation and intermediate products of unburned-zone autoignition reactions as formaldehyde. In the present study, knock-limit engine operation is carried out using different fuels with the RON's of 85 to 120, and autoignition process is computed for the fuels using a detailed reaction mechanism. The essential of the interaction and the effect of the deceleration on the relationship between combustion phase and knock intensity are discussed.

Proposal and Feasibility Study of New Combustion Analysis Method based on Heat Release Rate Prediction Using Machine Learning

Shojun Rachi･Kaname Naganuma (Kanazawa Institute of Technology)

The original combustion analysis concept previously proposed by the authors is reconstructed using recent machine learning techniques. Machine learning–based algorithms are applied to optimize the Wiebe function coefficients to fit the experimentally derived heat release rate, enabling the prediction of in-cylinder pressure profiles and demonstrating the potential for highly accurate engine performance prediction.

Analysis of Hydrogen Jet Characteristics and Concentration Distribution by Simultaneous LIF and Schlieren Method Measurements in a Constant Volume Chamber

Hyun Jo･Masayasu Shimura･Taku Tsujimura (AIST)･Satoaki Ichi･Kyohei Izumi (Kawasaki Motors)･Hirotaka Kawatsu･Genki Shigeno (Honda Motor)･Narumi Hiramoto (Yamaha Motor)･Yoshinari Ninomiya (Suzuki Motor)

This study aims to understand the behavior and diffusion of hydrogen when a hydrogen jet is injected into a combustion chamber as a fuel. To achieve this, simultaneous measurements using Laser-Induced Fluorescence (LIF) and Schlieren methods were conducted in a constant volume chamber. The analysis examined how hydrogen distribution characteristics and internal concentration distribution vary under different injection and ambient pressure conditions, providing insights into behavior of hydrogen jet.

In-Cylinder Temperature Measurement of a Hydrogen Internal Combustion Engine Using Near-Infrared Two-Color Pyrometry

Fangsi Ren･Shinji Nakaya･Mitsuhiro Tsue (The University of Tokyo)･Hiroshi Kato･Kyohei Izumi･Satoaki Ichi (Kawasaki Motors, Ltd.)･Tomohiko Kamio (Yamaha Motor)･Kenichi Sano･Koichiro Matsushita (Honda Motor)･Yoshinari Ninomiya (Suzuki Motor)

Hydrogen is attracting attention as a promising alternative fuel for internal combustion engines aimed at achieving carbon neutrality. In this study, the in-cylinder flame temperature evolution of a hydrogen engine was evaluated using a two-color temperature measurement technique. The method employs a high-speed camera to simultaneously acquire near-infrared emissions from water vapor at two wavelengths below 1.1 μm, enabling a time-resolved temperature quantification.

Study of In-Cylinder Combustion Phenomena by Simultaneous Dual-Direction In-Cylinder Direct Imaging in a Direct-Injection Hydrogen Engine for Motorcycles

Kyohei Izumi･Hiroshi Kato･Yoshinori Nakao･Yusaku Matsumoto･Ryosuke Yokoyama (Kawasaki Motors, Ltd.)･Tomohiko Kamio (Yamaha Motor)･Yusuke Marui･Kenichi Sano (Honda Motor)･Yoshinari Ninomiya (Suzuki Motor Co., Ltd.)･Satoaki Ichi (Kawasaki Motors, Ltd.)

In the pursuit of carbon neutrality, the practical implementation of hydrogen engines necessitates a comprehensive understanding of in-cylinder phenomena, particularly with respect to fuel economy and emissions. This study employs a direct-injection hydrogen engine for motorcycles and utilizes simultaneous dual-direction optical access to capture in-cylinder processes, enabling detailed observation of combustion chamber phenomena across a wide spatial domain.

Elucidation of In-Cylinder Abnormal Combustion Phenomena by Simultaneous Dual-Direction In-Cylinder Direct Imaging in a Direct-Injection Hydrogen Engine for Motorcycles

Hiroshi Kato･Kyohei Izumi･Ryosuke Yokoyama･Yusaku Matsumoto･Satoaki Ichi (Kawasaki Motors, Ltd.)･Tomohiko Kamio (Yamaha Motor)･Yoshinari Ninomiya (Suzuki Motor Co., Ltd.)･Kenichi Sano･Yusuke Marui (Honda Motor)･Yoshinori Nakao (Kawasaki Motors, Ltd.)

The suppression of abnormal combustion, including pre-ignition and knocking, is a major challenge in research aimed at the practical application of hydrogen engines for achieving carbon neutrality. As part of efforts to elucidate the mechanism of abnormal combustion in high-speed operation of motorcycle engines, this study attempted to identify the onset of abnormal combustion by simultaneously capturing a wide in-cylinder region from two viewing directions.

Analysis of Flame Propagation Behavior and Wall Heat Flux in Direct-Injection Hydrogen Motorcycle Engines

Yuki Kaga･Masakuni Oikawa･Yuji Mihara･Shoki Mashiko･Aoshi Yokomori (Tokyo City University)･Takumi Iwata (MOTORA,Inc.)･Hiroshi Kato･Kyohei Izumi (Kawasaki Motors,LTD.)･Kenichi Sano (Honda Motor)･Tomohiko Kamio (Yamaha Motor)･Yoshinari Ninomiya (Suzuki Motor)･Michiyasu Owashi (MOTORA)

Multiple heat flux sensors were placed on the cylinder head of a motorcycle direct-injection hydrogen engine. The instantaneous heat flux results obtained were used to analyze flame propagation behavior. Furthermore, CFD analysis and in-cylinder visualization results under identical conditions were compared to understand the cylinder flame propagation behavior dependent on operating conditions, such as the excess air ratio.

Investigation of In-Cylinder Hydrogen Mixture Formation by In-Cylinder Schlieren Observation in Hydrogen Direct Injection Engine

Atsushi Hisano･Yota Sakurai･Keisho Tanaka･Masahito Saito (Kawasaki Heavy Industries)･Satoaki Ichi (Kawasaki Motors)

In a hydrogen direct injection engine, the formation of a mixture of hydrogen and air in the cylinder is an important factor for combustion stability. Though in-cylinder CFD is utilized for grasping in-cylinder mixture formation, verification of hydrogen diffusion phenomenon in the cylinder is insufficient. In this study, the schlieren image in the cylinder is taken by the visualization engine to grasp the hydrogen diffusion, and the accuracy improvement of the hydrogen diffusion prediction in the engine cylinder analysis is examined.

Study of Engine Combustion in Cold Condition in Use of Methanol Blended Fuel

Tetsuya Ohira (Aichi University of Technology)･Keisuke Ito･Makoto Kaneko･Hidenori Fujii･Naoyuki Suda･Yoshinari Ninomiya (Suzuki Motor)

Methanol is currently under investigation as a carbon-neutral fuel for engines. However, its properties, such as its low boiling point and latent heat, pose challenges for cold-start engine combustion. In this study, we investigated a production motorcycle spark-ignited (SI) engine. Our research focused on fuel vaporization in the intake port, temperature distribution around engine components, and exhaust and crankcase gas emissions, alongside combustion stability during cold start. We found that poor fuel vaporization in the intake port were the root cause and the improvement target for degraded combustion stability following engine startup. Oil dilution may constitute a separate, critical issue.

A Study on Predicting Backpressure in Mufflers with Exhaust Variable Valves

Yunjeong Shim･Jaeyeon Jo･Yongwoo Mo (Hyundai Motor)･Jeongsu Koo･Jinman Shin (Sejong)

This study proposes an integrated methodology for predicting the backpressure performance of mufflers equipped with variable valves by combining experimental and analytical approaches. An airflow rig-based evaluation system was developed to replicate internal combustion engine (ICE) and hybrid electric vehicle (HEV) operating conditions. To enhance one-dimensional (1-D) simulation accuracy, a novel parameter extraction technique was introduced. Furthermore, the influence of thermal aging on valve spring torque was investigated, revealing its significant impact on backpressure characteristics. The proposed approach improves the correlation between simulation and experimental results, enabling more accurate backpressure predictions. This advancement supports optimized exhaust system design and reduces development time during the early stages of vehicle development.

Development of a Hydrocarbon Pyrolysis Model Considering Catalyst Deactivation Behavior

Akiko Miura･Toshiaki Sakima･Hirotsugu Matsuda･Yuji Harada (Mazda)

In the development of technologies for carbon recovery from hydrocarbon fuels, it is essential to construct a model that quantitatively represents the hydrocarbon pyrolysis reaction. During pyrolysis, H₂, CH₄, and carbon are generated, and carbon accumulates on the catalyst surface, leading to deactivation and eventually reaction termination. To reproduce this phenomenon, we developed a model that incorporates both pyrolysis rates and the progression of deactivation, based on experimental results.

Key Technology of Brand-New 1.5 L Three-Cylinder Engine for the Third-Generation Series Hybrid Powertrain (First report)
-Development of Combustion Technologies-

Isei Matsuzaki･Futoshi Yoshimura･Taichi Ando･Akihiro Shikata･Yukiyo Yamada (Nissan Motor)

Development of a new 1.5L engine focused on improving thermal efficiency through high-speed combustion, extensive EGR, and a high compression ratio. The characteristics of 100% electric drive, which allow the engine operating range to be limited, were utilized to enable combustion technologies optimized for these conditions. This paper presents these technologies and their performance evaluation results.

Key technology of Brand-New 1.5L 3 Cylinder Engine for 3rd Generation Series Hybrid Powertrain (2nd report)
-Fuel Economy Improvement-

Taichi Ando･Isei Matsuzaki･Akihiro Shikata･Yukiyo Yamada (Nissan Motor)

In developing a brand-new 1.5L engine, average thermal efficiency was introduced during on-vehicle driving as an index of fuel economy. This efficiency was improved through control that leverages characteristics of an electric power generation-dedicated engine to achieve optimal operating points considering an improved warm-up temperature profile.

Performance Evaluation of Flat-Type Dynamometer for Road Simulation Using Driving Force Control of In-Wheel Motor Electric Vehicle

Sakahisa Nagai･Tokikazu Mizuguchi･Yuna Morimoto･Daisuke Gunji･Osamu Shimizu･Hiroshi Fujimoto (The University of Tokyo)･Yuichi Takasaki･Kentaro Kondo･Kohei Tasumoto･Yoshihisa Hojo (Toyo Denki Seizo)

A dynamometer can simulate the vehicle motion by accurately reproducing the reaction force from a road acting on vehicle wheels. An in-wheel motor (IWM) electric vehicle can precisely control the reaction force from a road due to its high torque responsiveness and direct-drive capability. In this paper, the performance of a newly developed flat-type dynamometer that can be installed in a wheel-well is evaluated using the driving force control of an IWM electric vehicle, and the results are compared with those obtained on an actual road.

Road Condition Simulation Control in Vehicle Bench Testing Using a Flat-Type Dynamometer

Kentaro Kondo･Yuichi Takasaki･Yoshihisa Hojo･Kohei Yasumoto･Kenji Terada･Daisuke Kozakai･Koichi Eitoku (Toyodenki Seizo)

Vehicle bench testing using a dynamometer makes it possible to simulate low-μ road conditions and cornering motion by linking it with a vehicle model. In this paper, we report on simulated control of road conditions using two types of flat-type dynamometers we developed, and on the behavior of the vehicle drivetrain that becomes problematic as the control bandwidth improves, and how to deal with this on the equipment side.

Measurement of Tire/Wheel Vibrations During Rolling Using a Compressed Sensing DIC

Yuki Kato (Kochi University of Technology)･Soma Watahiki (Kozo Keikaku Engineering)･Masayoshi Otaka (Ono Sokki)･Mitsuki Togoshi (Kozo Keikaku Engineering)･Yoshiho Oda (Ono Sokki)･Kota Matsumura (Kochi University of Technology)

Tyres in motion receive excitation forces from the road surface and exhibit complex vibration behaviour. However, as they are high-speed rotating bodies, it is difficult to measure their vibration using contact sensors with cables. This research therefore developed a method using compressed sensing and digital image correlation to measure the detailed vibration modes and frequency spectra of tyres when they are overriding a tyre-mounted protrusion.

Simultaneous Measurement of Frictional Force Fluctuations and Wear Debris Behavior under Semi-Dry Conditions toward Understanding the Creep-Groan Phenomenon

Hikaru Okubo･Junpei Suzuki (Yokohama National University)･Shuhei Tanamachi･Kenta Kurimoto･Yusuke Sunagawa･Yoshiyuki Yamaguchi (Nisshinbo Brake)･Ken Nakano (Yokohama National University)

To elucidate the creep-groan phenomenon that occurs in braking systems, we developed a fundamental experimental platform enabling the simultaneous measurement of frictional force fluctuations and wear debris dynamics under semi-dry sliding conditions—factors believed to be intrinsically linked to this phenomenon. Herein, we report the results obtained from these simultaneous measurements.

Characterizing Racing Tires on a Realistic Indoor Surface

Alexander O'neill (GCAPS)

Tires are traditionally characterized using indoor flat-track machines with sandpaper surfaces, which generally overpredict performance relative to outdoor driving, especially for racing tires. This limits correlation and accuracy when applying such data or models in vehicle simulations. To address this, a novel flat-track surface was developed with a surface roughness much more representative of real roads. Racing tires were evaluated on the surface and benchmarked against outdoor measurements, supported by analysis of rubber material properties. The surface produced an improved correlation with outdoor behavior, thus offering a new way to enhance understanding and predict tire and vehicle performance.

Improving Tire Models via Optimized Tire Testing
-Enhancing Tire Model Accuracy Through Optimizing Methodology on Indoor Test Machines-

Anders Edward Maki (MTS Systems Corporation)

The test methodology and machine can affect the data obtained from tire testing on indoor test systems. This presentation highlights how different test methods can vary the repeatability of longitudinal force data during braking events. In addition, it will compare lateral force data from two machines to show correlation quality between indoor test systems. Optimizing the test method and machine can improves the data quality, which enables more accurate tire models.

A Predictive Thermo-Mechanical Framework for Tire Temperature and Performance Modeling

Francesco Calabrese･Manfred Baecker･Axel Gallrein･Christoph Burkhart･Tobias Ruhwedel (Fraunhofer institute for industrial mathematics)

The growing demand for sustainable products drives the industry to improve CAE methods for predicting wear and rolling resistance, both strongly temperature-dependent. The authors work enhances temperature modeling and parameterization in the thermo-mechanical CDTire model. Its finite-volume formulation separates geometry from material properties, improving physical accuracy and therefore reducing parameter identification effort due to enhanced prediction capability. A measurement-based methodology is presented and validated on multiple passenger-car tires, showing improved accuracy of standard characteristics with minimal extra effort. Temperature effects on cornering/braking stiffness, friction, and pressure are examined in details. Future work targets improved rolling-resistance and wear prediction.

Measuring Braking Stiffness Using a Novel Intelligent Tire

Hiroshi Tachiya･Syunnosuke Fukumitsu･Kazunori Onishi･Akira Shibuya･Masahiro Higuchi (Kanzawa univ.)･Naoki Sekino･Kenta Konishi･Masakatsu Kakura･Daisuke Yokoi (Suzuki Motor)

In this study, the triaxial loads acting on the tire ground surface were measured from wheel strain, together with the vehicle's running condition during straight driving under various road surface conditions. From the measured results, the relation between the road friction coefficient and slip ratio was derived, and the braking stiffness was evaluated.

Measurement of Tire Contact Loads and Cornering Stiffness during Turning Maneuvers with a Novel Intelligent Tire

Ryosuke Urasaki･Taiga Horie (Kanazawa Univ.)･Akira Sibuya･Masahiro Higuchi･Hiroshi Tachiya (Kanzawa univ.)･Naoki Sekino･Kenta Konishi･Masakatsu Kakura･Daisuke Yokoi (Suzuki Motor)

This study presents a method to determine the triaxial load acting on the tire contact surface from the wheel strain of the tire, and to measure the tire contact load accurately when the vehicle is turning. In addition, the road friction coefficient is obtained from the tire contact load measured under various conditions, and the cornering stiffness is calculated.

A Highly Robust Tire Contact Load Measurement Method Utilizing Wheel Deformation

Shungo Tomita･Keisuke Maeno (Kanazawa Univ.)･Akira Sibuya･Masahiro Higuchi･Hiroshi Tachiya (Kanzawa univ.)･Naoki Sekino･Kenta Konishi･Masakatsu Kakura･Daisuke Yokoi (Suzuki Motor)

This study proposes a measurement method for tire-road force that is highly robust against measurement noise. This method enables tire-road force measurement using only tire rotation speed to identify tire revolutions and strain measurements occurring on the wheel. Measurement experiments were conducted during straight-line driving, and the usefulness of this method was confirmed by quantitative evaluation of the measured tire ground load values against true values.

Measurement of Tire Contact Load Using a Strain-Sensing RFID Sensor Tag

Tomoki Ikegami･Syogo Tacguchi (Kanazawa Univ.)･Masahiro Higuchi･Hiroshi Tachiya (Kanzawa univ.)･Kunihiro Komaki･Tomu Tanabe･Youichi Saito (Murata)

RFID tags are used for inventory management of goods as a technology to exchange information wirelessly without power supply. In this study, a basic study was carried out to measure the grounding load by embedding an RFID tag sensor with a strain measurement function in a tire, and the result was confirmed.

Investigation of μ-S Characteristics Using an Indoor Flat Road Tire Measurement System

Masami Matsubara (Waseda University)･Daisuke Yokoi (Suzuki Motor)･Takayuki Toyoshima (Honda Racing Corporation)･Takeshi Hotaka (Honda Motor)･Ichiro Kageyama (Nihon University)･Hideki Sakai (Kindai University)･Hiroshi Tachiya (Kanazawa University)･Yoshiho Oda (Ono Sokki)･Kazuaki Inoue (A&D Company)･Masahiko Matsumoto (Kokusai)･Naohiro Ishigami (TOYO TIRE)･Isao Kuwayama (Bridgestone)･Yoshinori Saito (Nihon Michelin Tire)･Haruyuki Suzuki (Sumitomo Rubber Industries)･Naoto Miyashita (The Yokohama Rubber)

In this study, the μ–S characteristics were investigated using an indoor flat road tire measurement system that enables stable control of environmental conditions, including road surface position, vertical load, tire inflation pressure, and water film thickness. The μ–S characteristics were measured under low-speed conditions while varying the dry and wet road surface, vertical load, and tire inflation pressure. The results demonstrated high reproducibility of the μ–S curves regardless of the measurement section, highlighting the superiority of the indoor testing environment.

Effects of Regional Airflow from a Fan-Integrated Car Seat on Thermoregulatory Responses and Thermal Comfort Under a Comparable Resting Skin-Temperature Environment

Hayato Takahashi･Kentarou Wada･Teruyuki Nagai (Kyoto Institute of Technology)･Tetsuya Kitagawa (Fortech)･Yukiko Nishizaki･Naoyuki Yamashita (Kyoto Institute of Technology)

This study examined the effects of airflow from a fan-integrated car seat on body temperature and thermal comfort in an environment with temperature comparable to resting mean skin temperature. Fans were installed in the backrest and seat cushion. Results showed that body temperature remained unchanged regardless of airflow. However, whole-body thermal comfort improved most in the condition with airflow provided from both backrest and seat cushion, followed by similar moderate improvements from either location alone. These findings suggest that providing airflow from car seats improves thermal comfort without affecting body temperature, with dual-cushion airflow offering greater benefits.

Arousal State Assessment Using Blink Pattern Analysis Based on Camera Images in a Simulated Automated Driving Environment

Hiroki Takeuchi (University of Occupational and Environmental Health)･Mieko Ohsuga･Yoshiyuki Kamakura (Osaka Institute of Technology)

In automated driving levels 3, authority may be transferred to the driver in emergency situations, making it necessary to monitor the driver's attention and arousal states. Therefore, we are examining an arousal state assessment method that uses changes in the occurrence ratios of blink patterns estimated from camera images as one of the indices. In this presentation, we report the results of applying this method to arousal-decline experimental data obtained in a simulated automated driving environment.

Relationship between Eye Movement Characteristics and Electrodermal Activity Associated with Decreased Level of Arousal

Shinta Sano･Takeshi Kohama･Shogo Mineta (Kindai University)

This study aimed to verify whether slow eye movements (SEM) estimated from fixation eye movements could serve as an objective indicator of arousal. To this end, simultaneous measurements of fixation eye movements and skin conductance were conducted. The results confirmed that the SEM in fixation eye movements appeared near the point where long-term fluctuations in skin conductance exhibited a negative peak.

A Method for Estimating Changes in Drivers' Sense of Safety and Confidence During On-Road Driving Using Physiological Data from Wearable Devices

Koki Yasuda･Mayu Kurozumi (Keio University)･Seishi Takagi･Takuya Izumiguchi･Kento Mera (Penstone)･Miwa Nakanishi (Keio University)

This study proposes and evaluates a method for estimating drivers' sense of safety and confidence levels, which changes in response to driving situations, using physiological data obtained from wearable devices. A real-world driving experiment was conducted with 10 participants in an urban area, during which continuous physiological data were collected from drivers alongside subjective ratings of comfort. Using these data, a predictive model was developed to estimate the drivers' sense of safety and confidence.

Basic study of Haptic Navigation for Electric Scooter

Tomosuke Maeda･Keisuke Otaki･Takayoshi Yoshimura (Toyota Central R&D Labs.)･Tomoaki Mitsuhashi･Takafumi Horigome (Toyota Motor)･Hiroyuki Sakai (Toyota Central R&D Labs.)

Electric scooters (e-scooters, ES), are increasingly used as last-mile options in sharing services. At the same time, traffic accidents involving ESs have become a concern. Inappropriate riding behavior when using electric scooters is often cited as a main cause. This study compared a conventional navigation app and a haptic navigation method under conditions close to real traffic environments, and evaluated the characteristics and effectiveness of each.

Development of Wakefulness-Maintenance Support Technology Using Stochastic Resonance

Shimpei Kusumoto･Yutaro Sato･Masato Anegawa･Wataru Yoshida･Yoshitaka Fujihara (Mazda)･Yoshiharu Yamamoto･Ikuhiro Yamaguchi (The University of Tokyo)

Conventional drowsiness alerts encourage breaks but provide limited awakening, risking drowsiness before reaching a rest area. This study applies “stochastic resonance,” where subtle noise stimuli activate the body at optimal intensity, to propose a new HMI that maintains driver alertness without increasing discomfort, ensuring safe travel to the nearest rest stop.

Effect of the See-Through A-pillar using Mirror on Pedestrian Detection Time during Right Turn at Intersection

Yujiro Mizobuchi (MIRISE Technologies)･Kunitomo Aoki･Akio Hirano (Nagoya Univercity)･Kazuyuki Ishihara･Kojiro Tachi･Masaaki Kawauchi (MIRISE Technologies)･Hirohumi Aoki (Nagoya Univercity)

Blind spots caused by the A-pillar can delay pedestrian detection at intersections, potentially leading to traffic accidents. This study investigates the effectiveness of a device that renders the A-pillar transparent using mirrors, focusing on pedestrian detection time during right turns at intersections. Experimental results indicate that the device enables drivers to detect pedestrians on average 0.6 seconds earlier, suggesting a meaningful improvement in situational awareness and safety.

Study on Automotive Seat Vibration for Improving Driver Situational Awareness

Yukiyo Kuriyagawa･Xinyue Zhang (Nihon University)･Hidefumi Koizumi･Shinichi Sagawai･Hiroshi Wakuda･Toshiki Nakamura･Keigo Abe･Kunio Sato (Alps Alpine)

This study aims to achieve comfortable intuitive driving assistance by using seat vibration as an alternative to, or in combination with, visual and auditory stimuli. To enhance the driver's situational awareness of the vehicle's surroundings, we present findings from investigations involving variations in seat vibration frequency.

Inclusive HMI Design to Mitigate Mode Confusion in Multilevel Driving Automation

Turkan Hentati (Human Factors Engineer)･Oana Moldovan (R+D Senior Engineer)

This paper investigates the challenge of mode confusion in automated driving through a dedicated use case about multilevel driving developed within the European project CERTAIN. Although automation promises more accessible and safer mobility, mode confusion remains a major obstacle, particularly for diverse user groups such as people with disabilities, older adults, novice and expert drivers. Building on state-of-the-art literature highlighting flexibility, personalization, and error tolerance as essential principles of inclusive HMI design, we underscore the need to explicitly capture and integrate the specific needs of these profiles. Our analysis will combine these insights with interviews conducted in CERTAIN, acknowledging that each individual is unique and requires tailored interaction strategies to support clearer mode awareness.

Multi-pillar Framework for the Assessment of Human Machine Interaction in Automated Vehicles

Jeroen Hogema･Saarang Gaggar･Jan Souman･Hari Hara Sharan Nagalur Subraveti･Chris Van Der Ploeg･Marijke Van Weperen･Marieke Martens (TNO)

Effective user–automation interaction is critical for partial (SAE L2) and conditional (L3) vehicle automation. Users must clearly understand automation states, while HMIs should adapt to user behavior and promote safety. Current ISO standards lack comprehensive coverage and are inconsistently applied. This paper introduces a multi-perspective framework: evaluation of HMIs through a questionnaire; training requirements for users; teamwork based framework for assessing the interaction; and an adapted ISO 21448 (SOTIF) process to create a structured approach for the assessment of the interaction. Results from simulator experiments and ongoing studies demonstrate the framework's potential for guiding assessment of user–automation interaction.

A Study of Super-Plasticity in Low Density Steel Sheet

Junyeong Jeong･Jaeyoon Hwang･Minwoo Kang (Hyundai Motor)･Jeongho Han (Hanyang University)

Low density steel sheets can exhibit super-plasticity properties under characteristic composition and process conditions, so they can be applied to large-sized plate parts with high forming difficulty based on high elongation in a single press process, which has the advantages of process simplification (welding deletion, etc.) and mold reduction. We designed various compositions of Fe-Mn-(Al-Si)-C low-specific-weight steel sheets, evaluated super-plasticity properties, analyzed the cause of its occurrence, and verified the properties at room temperature in consideration of future part applicability

Development of Delayed Fracture Prevention Technology for High-Strength Steel Sheet Parts

Masaya Yagura･Yusuke Tsunemi･Naoki Kimoto･Masahiro Kubo (Nippon Steel)

In general, hydrogen embrittlement cracking can be a concern in high-strength materials. In this study, assuming automotive components as the application, we focused on the influence of deformation and residual stress on hydrogen embrittlement cracking at sheared edges. Our group investigated methods to reduce residual stress at the sheared edge and, as one example, verified that compressing the sheared edge effectively decreases the residual stress.

Oxidation Behavior of Ferritic Stainless Steels under a Simulated Hydrogen Combustion Atmosphere

Yoshitomo Fujimura･Atsutaka Hayashi･Naoki Hirakawa･Junichi Hamada (Nipponsteel)

The steam oxidation behavior of various ferritic stainless steels was investigated under a simulated hydrogen combustion atmosphere consisting of 30% H₂O–N₂ at 400-700 ℃ for 100 hours. For pickled surface, steels showed the greatest weight gain at 600 ℃ in these conditions, and oxidation resistance improved with increasing Cr and Si content. Furthermore, even steels with low Cr and Si showed significantly suppressed oxidation when their surfaces were polished.

Quantification of the Influence of Factors on Abnormal Grain Growth in Carburized Steel Parts for Drivetrain: Part III

Yasuo Itou･Gou Katou･Makoto Maeda (JATCO)･Tsubasa Yamashita･Naoki Wada･Shuhei Kojima (MI-6 Ltd)･Junya Inoue (The University of Tokyo)

Abnormal grain growth that causes strength reduction occurs in hot-forged carburized drivetrain parts. Predicting this phenomenon is difficult due to its complex occurrence mechanism. In this study, we developed a method to predict the occurrence of abnormal grain growth from controllable factors during part manufacturing by analyzing test results that simulate hot forging using machine learning.

Development of molten flame-retardant magnesium alloys for die casting

Yasumasa Chino (AIST)･Hiroshi Komai (The Japan Magnesium Association)

In the Japan Magnesium Association's “Automotive Magnesium Application Expansion Committee” (2014–2018), efforts were directed toward enhancing safety and eliminating the need for protective cover gases by developing molten flame-retardant magnesium alloys for die-casting, which exhibits significantly reduced flammability during the melting process. In the presentation, we show the flame-resistant behavior of the developed alloy, along with its mechanical and corrosion properties, and further report on the characteristics of prototype components fabricated using the material.

On the Fatigue Limit Diagram and Fatigue Life Prediction Models

Gyoko Oh (Tokyo Roki)

The fatigue limit and lifespan vary depending on the loading mode and are also greatly affected by stress concentration. The effect of mean stress has been mathematically expressed using several models, but based on experimental data, the Walker model has been shown to be the most appropriate and to have high predictive accuracy. The same was true for the effect of assembly stress due to welding on the fatigue limit and the threshold stress intensity range.

Design Quality Assessment Using Forming Deformation Prediction for Automotive Interior Decorative Films

Tomohiko Anazawa (Dai Nippon Printing Co., Ltd.)

We developed a simulation approach that predicts the deformation behavior of interior decorative films during forming and enables design-stage evaluation of visual quality. The method helps identify potential distortion and appearance issues before prototyping. To demonstrate its effectiveness, we present application cases showing how this approach supports design decisions and reduces rework in the development process.

Design Approach and Structural and Functional Design for a Small Last-Mile Delivery Mobility

Mizuki Takehara (Toyota Motor)

This talk introduces the design and development of a small four-legged delivery robot suited to Japan's narrow backstreets. Its gentle, non-threatening form, low-center-of-gravity package, and integrated lighting for load assistance and simple expressive cues are designed to make the robot easy to accept in daily life. The approach illustrates how functional performance and human-friendly presence can be achieved together in last-mile mobility.

Colreo Design

Keishi Fukumoto (K-TEC Corporation)

Design process and goals of the four-legged mobility vehicle, "Corleo," which was exhibited at the Osaka Kansai Expo.

Development of an Open-Source Standardized Fastening Platform for In-Vehicle Accessory Ecosystems

Jinseok Yoon･Jaeeun Chang･Kwangrae Jo (Hyundai Motor)･Junghyung Cho･Sungjin Kim･Kiseob Nam (PIOLAX)

This study presents an innovative open-source platform fastening system designed to transform vehicle interiors into customizable lifestyle spaces. Based on comprehensive customer research identifying key pain points in existing automotive accessories, we developed two core attachment mechanisms: rotational and vertical types, utilizing optimized plastic materials without additional hardware. The platform underwent rigorous validation including ES specification testing, certified external evaluations, and vehicle-level assessments. Successfully mass-produced under the Hyundai/Kia 'AddGear' brand, the system has secured 14 patents globally and is currently applied across multiple vehicle models, establishing a foundation for an expandable aftermarket ecosystem.

Development of Advanced Technologies for Further Functional Integration of Components

Toru Yonebayashi･Tasuku Zeniya･Atsushi Ohno･Mashiko Abe･Takashi Kawachi･Masahiro Kubo･Kenta Ikegami･Toru Okada･Hiroshi Yoshida (Nippon Steel Corporation)

Rear modules and floor modules are introduced as high-performance integrated components made from hot-stamped steel sheets. In addition, structures and forming technologies that enable further improvements in crash performance compared to conventional integrated components are presented.

Development of Reinforcement Structure for Hat Shape Component under Eccentric Loads

Shuki Nakamura･Kenichi Watanabe･Mie Tachibana (Kobe Steel)

Due to the increase in vehicle weight associated with BEV adoption, structures capable of absorbing higher collision energy than before are required. In this study, we examined reinforcement structures for hat-shaped components using crash simulation. Our focus was on designs that provide superior energy absorption performance relative to component weight. The evaluation was conducted under conditions simulating an ODB frontal impact, where axial crushing and bending occur simultaneously. The configuration in which small hat-shaped members are arranged on the hat web surface demonstrated excellent energy absorption efficiency.

Analysis of Material Properties and Structural Factors on Impact Resistance of Door Trim

Yumiko Unrinin (DAIHATSU MOTOR .CO.JP)･Hirofumi Kishi･Kazuyoshi Baba (DAIHATSU MOTOR.CO.JP)

As digital twin technology is increasingly utilized in automotive design, the prediction of impact resistance has become one of the most important issues. While polymer components enable the realization of diverse designs, the prediction of their impact resistance is significantly complicated due to inhomogeneous stiffness and the nonlinear stress-strain behavior. In this study, we investigate the correlation between the impact resistance of actual components and the material properties evaluated using flat plate specimens, and report the factors effects impact resistance.

Mechanical Properties and Formability of Steel Sheets Made from Obsolete Scrap in Electric Arc Furnaces

Noriyuki Nakanishi･Masaru Iwasaki･Shintarou Adachi･Eizaburou Nakanishi (TOKYOSTEEL)

The aim is to promote domestic recycling of iron scrap, approximately 8 million tons of which are exported annually. While elements such as copper contained in obsolete scrap have been considered to degrade properties, few reports exist on actual automotive steel sheets manufactured. This report presents the effects on mechanical properties and formability of steel sheets when varying the content of these elements.

Investigation of Optimal Combustion Concept for Oxymethylene Dimethyl Ether (OME)

Kazuya Miyashita･Shinya Furukawa･Hisashi Ozawa (Isuzu Advanced Engineering Center)

Oxymethylene dimethyl ether (OME) exhibits distinct fuel characteristics compared to conventional diesel, including significantly reduced soot emissions and late combustion, but it also has a lower heating value and tends to increase heat losses. Consequently, it is necessary to investigate combustion systems specifically optimized for OME. This paper presents a novel OME combustion concept combining a large nozzle diameter, low injection pressure, and a high compression ratio. The performance of this concept was evaluated through experimental investigations on a single-cylinder engine, complemented by in-cylinder combustion visualization.

Effects of Hydrogen Substitution Ratio on the Performance and Emission Characteristics of a Hydrogen–Diesel Dual-Fuel Engine

Teofan Kishi･Motoki Nishizawa･Satoshi Nakatani･Apichai Tripatara･Naoto Horibe･Hiroshi Kawanabe (Kyoto University)

In this study, an experimental investigation was conducted using a single-cylinder engine to examine hydrogen–diesel dual-fuel combustion. Under steady-state, constant-speed operation, the total input heat was maintained constant while the diesel injection timing and the hydrogen substitution ratio (0–90%) were varied. The effects of these parameters on engine performance and exhaust characteristics, including soot particle size distribution, were evaluated.

Application of Next-Generation Biodiesel Fuel HVO to an Inline 6-Cylinder 3.3L Diesel Engine

Yusuke Nishioka･Takeru Matsuo･Tomoyuki Kanda･Daisuke Fukuda･Jun Kanzaki･Makoto Namba･Sangkyu Kim･Daisuke Shimo (Mazda)

Mazda proposes a strategy that offers not only battery electric vehicles but also highly efficient internal combustion engine vehicles combined with carbon-neutral fuel during transition to renewable generation toward carbon neutral by 2050. This paper introduces the combustion concept that enables HVO, which is widely used in Europe, to the 3.3L diesel engine as drop-in fuel and the performance and reliability verification results.

Development of an Intake Air Temperature Estimation Method for Transient Control of Diesel Engines (First Report)
-Proposal of an Intake Air Temperature Estimation Formula for Steady-State Operation-

Kazuhisa Inagaki (TOYOTA CENTRAL R&D LABS)･Akitaka Ueno (Toyota Industries Corporation)･Tsubasa Sugano (Toyota Motor)･Takeshi Nishio (Toyota Industries Corporation)

In modern common-rail diesel engines, noise and exhaust emissions are controlled through multi-stage fuel injection. For optimal pilot injection control, intake air temperature prediction is crucial. In this study, the in-cylinder temperature at intake valve closing (Tivc) is defined, and a predictive formula under steady-state operation is proposed. Tivc can be estimated as a linear combination of intake manifold gas temperature, coolant temperature, and engine output. Simulation results agree with experimental data, confirming the validity of the proposed formula.

Range Extender ICE Solutions to Accelerate Time-to-Market for HD BEV Trucks

Anton Arnberger (AVL List)･Toro Nishizawa (AVL Japan)･Daniele Corsini･Bernhard Raser (AVL List)

In different markets, commercial vehicle manufacturers face increasingly stringent CO₂ regulations. Today, there are viable use cases for battery-electric trucks (BEVs), particularly when cost-effective charging at depots is possible. However, operational flexibility remains limited: public charging infrastructure is often unavailable, impractical in dense metropoles such as those in Japan, or expensive in terms of cost per kWh. This presentation introduces a diesel-based industrial range extender (REX) integrated into a BEV truck as a bridging solution. Diesel offers efficiency, durability, and logistical compatibility for this application. Nevertheless, its role as a range extender requires targeted modifications to achieve maximum efficiency across relevant mission profiles while ensuring the most compact packaging. The publication will address the dedicated engine design for REX applications as well as key aspects of vehicle integration.

Evolving HD Engine Efficiency to the Next Level
-A Pathway to 56% Brake Thermal Efficiency for Commercial Applications-

Anton Thomas Koerfer (FEV Group)･Lukas Virnich (FEV Europe)･Michael Franke (FEV North America)･Stefano Ghetti･Ulrich Gruetering (FEV Europe)

The Diesel powerplant in heavy applications characterizes all over the world the backbone of goods transport. Driven by a variety of objectives, fuel efficiency has always displayed an engineering goal and will continue in the mid-term horizon. This paper reviews an innovative study based on an in-series engine definition in the 2 l/cyl class. The most important aspects include design elements as uplifted combustion pressure with higher compression ratios and innovative bowl geometries, supported by upgradations on fuel and air delivery side, but include also novel S/B ratios and adjusted stroke characteristics, plus thermal coating for reduction of heat losses

Relationship between Wall Surface Roughness and Flow Field inside a Spray Flame after Wall Impingement

Yoshio Zama･Yusei Fukamachi (Gunma University)･Shinya Furukawa (Isuzu Advanced Engineering Center, Ltd)

In this report, the effect of wall roughness on the flow field of spray flames In this report, the effect of wall roughness on the flow field of spray flames impinged on the wall based on velocity information obtained over macroscopic and microscopic scales was investigated. The results indicate that the wall roughness employed in the experiments was smaller than the thickness of the viscous sublayer inside the spray, and consequently, no significant effect of wall roughness on the flow field along the wall surface was observed.

Thermal Efficiency improvement of a Diesel Engine by High-Heels Heat Release Rate Profile
-(Engine Experimental Results and Analysis by Utilizing Multiple-Injector System)-

Teruo Machii･Noboru Uchida (New A.C.E Institute)

Further increase in degree of constant volume combustion cannot necessarily achieve higher thermal efficiency probably caused by increased cooling loss. Therefore, High-heels heat release rate profile, which rather reduces degree of constant volume combustion, has proposed as a potential combustion concept to improve cooling loss and thermal efficiency simultaneously. To achieve the target profile, the feasibility of controlling heat release rate profile with more degrees of freedom by utilizing a multiple-injector system was numerically confirmed in the previous study. This study investigates the factors contributed to the thermal efficiency improvement by analyzing experimental results conducted by a heavy-duty single-cylinder engine.

Study on Direct CO₂ Capture from Motorcycle Exhaust Gases (Part II)
-Influence of Coexisting Species on CO₂ Adsorption Performance-

Takumi Miwa･Momona Hirao･Shogo Hashimoto･Toru Uenishi (Kitami Institute of Technology)

In our previous study, we demonstrated that carbon dioxide emitted from motorcycles can be directly captured, and we showed that while zeolites exhibit reduced CO₂ adsorption capacity compared with model-gas conditions, amine-impregnated silica exhibits improved performance. In this study, to clarify the factors responsible for this difference, we conducted model-gas experiments to investigate the influence of individual coexisting species on CO₂ adsorption capacity. The results provide insight into how specific exhaust components affect adsorption behavior and contribute to the development of more practical on-board CO₂ capture systems.

Study on On-Board Carbon Recycling Technology (Part II)
-Effect of Secondary Particle Size on Reverse Water-Gas Shift Activity under an Electric Field-

Koki Fujiwara･Toru Uenishi (Kitami Institute of Technology)

In our previous study, we demonstrated that the reverse water–gas shift (RWGS) reaction under an applied electric field can proceed under exhaust-gas conditions, indicating its potential for on-board carbon recycling. For practical implementation, establishing design guidelines for the particle size of catalyst supports used in the reactor is essential. In this study, we investigated the influence of the secondary particle size (aggregate size) of the catalyst support on RWGS activity under an electric field. The results provide insight into how support morphology affects reaction performance and offer guidance for designing reactors for on-board carbon recycling systems.

Study on Direct CO₂ Capture from Motorcycle Exhaust Gases (Part III)
-Effect of Adsorbent Hydrophobicity on CO₂ Adsorption Performance-

Hayato Enjo･Momona Hirao･Toru Uenishi (Kitami Institute of Technology)

In our previous study, we investigated the effects of coexisting gases on CO₂ adsorption capacity and showed that water vapor enhances adsorption performance. For practical implementation of on-board CO₂ capture systems, it is necessary to establish design guidelines for binders used to coat adsorbents onto honeycomb supports and other structures. In this study, we examined the influence of binder materials on CO₂ adsorption capacity under humid conditions, focusing on how the hydrophobicity of the adsorbent layer affects adsorption behavior. The results provide insights that contribute to developing practical binder formulations for on-board CO₂ capture applications.

Study on Direct CO₂ Capture from Motorcycle Exhaust Gases (Part IV)
-Effect of Adsorbent Impregnation Methods on CO₂ Adsorption Performance-

Toru Uenishi･Shogo Hashimoto･Momona Hirao･Toru Enjo (Kitami Institute of Technology)

In our previous study, we examined the influence of binder materials on CO₂ adsorption and showed that binder hydrophobicity plays a key role in the enhancement of adsorption under humid conditions. For practical implementation of on-board CO₂ capture systems, it is important to establish design guidelines for the impregnation methods used for preparing adsorbent layers. In this study, we investigated how different impregnation methods affect CO₂ adsorption capacity in the presence of water vapor. The results provide insight into the relationship between impregnation technique and adsorption behavior, contributing to the development of practical adsorbent preparation methods.

CO₂ Absorption Method in the Exhaust Gas by Droplet Impingement/Atomization Control of Absorbent using Surface Texturing (Second Report)
-Possibility of CO₂ Absorption Efficiency by Combining Chemical Absorption and Physical Adsorption Methods-

Tetsuo Nohara･Kentarou Watanabe･Keito Horiuchi･Shotaro Nara･Naoya Fukushima･Masayuki Ochiai (Tokai University)

In a previous report, we investigated a CO2 absorption method using a chemical absorption method that utilizes droplet impingement and atomization on a surface-textured plate, and confirmed the CO2 absorption efficiency at room temperature. In this report, in addition to these, we compared different gas temperatures/impingement plate temperatures. We discovered the possibility of a new CO2 absorption and capture system that combines a physical adsorption method using a CO2 adsorbent installed at the last position.

Research on On-Board CO₂ Capture Technology (3rd Report)
-Deriving System Requirements Using Machine Learning-

Junya Murata･Hirotsugu Matsuda･Daichi Takashima･Yuji Harada (Mazda)

In constructing a CO2 capture system from engine exhaust gas, it is necessary to derive the requirements for multiple factors that affect capture performance in order to achieve the target CO2 capture amount. However, an analysis using only 1D-CFD requires an enormous amount of computation time. Therefore, we utilized a machine learning model trained on 1D-CFD results to efficiently derive the system requirements.

Mechanical-Recycle Technology of Automobile Shuredder Residue

Shogo Izawa･Yuta Urushiuama･Akinori Yoshimura (Nagoya University)

we are developping mecoanical-recycle technology of automobile shuredder residue.We make automobileparts by using this recyed material.

Development of Chemical Sorting Technology for Removing Impurities from End-of-Life Automotive Plastic Parts

Yasushi Terasaka･Satoshi Hirawaki･Atsushi Hanaoka･Shinsuke Yabunaka･Shuta Suzuki･Shoko Namera･Haruki Chiba (Honda R&D)

Automotive plastic waste components typically contain various solid contaminants, including insert metals, rubber hoses, gaskets, and reinforcing materials such as glass fibers embedded within the resin matrix. These heterogeneous inclusions significantly hinder the recovery of high-purity resin through conventional mechanical separation techniques, which are often ineffective in isolating the resin from non-resin materials. To address this issue, we have developed a chemical sorting technology that enables selective dissolution of the target resin while efficiently removing contaminants. This process involves the use of solvents to dissolve the resin, followed by filtration and centrifugal separation to eliminate solid impurities. As a result, the method achieves a substantially higher separation purity compared to traditional approaches. Furthermore, the system is designed to accommodate complex composite waste and supports continuous processing, making it suitable for industrial-scale recycling operations. This technological advancement enables the high-quality recovery of resins derived from end-of-life vehicles and contributes to the realization of a sustainable circular economy in the automotive sector.

Environmental Impacts of Hydrothermal Acid Leaching of Lithium-ion Battery Cathode Materials

Zhengyang Zhang･Muhammed Isah･Panpan Wu･Qingxin Zheng･Ken Watanabe･Kazuyo Matsubae (Tohoku University)

Urban mining and the development of green recycling technologies for spent lithium-ion batteries represent critical strategies for transitioning toward a circular economy. This research employs life cycle assessment (LCA) to quantify the environmental impacts of a newly developed hydrothermal organic acid leaching process for the recovery of lithium, cobalt, nickel, and manganese from black mass, with the aim of elucidating the environmental advantages of the proposed process compared to existing acid leaching processes.

A Circular Economy Indicator for Vehicles (3)
-Examination of Methods for Evaluating Initiatives Aimed at "Promote Longer Use"-

Yoshiro Masuda (Toyota Motor)･Takamichi Iwata (Toyota Central R&D Labs.)･Kiyotaka Tahara･Mitsutaka Matsumoto (AIST)･Tomohiro Tasaki (National Institute for Environmental Studies)･Masashi Hara･Tetsuro Kobayashi･Daisuke Yamada･Hisaaki Takao (Toyota Central R&D Labs.)･Eiji Ishida･Takayuki Nagai (Toyota Motor)

Up to now, we have proposed evaluation indicators for resource circularity as a measure for assessing the circular economy, taking into account differences in material types. On the other hand, it is also important to reduce resource consumption by "promote longer use." In this report, we present our examination of methods for evaluating initiatives aimed at "promote longer use."

Optimal LCA : State of Health on End of life Automotive Systems and Their Reuse

Joel Op De Beeck･Vincent Cuvelier･Toshihiko Minami･Gabin Goy･Nissrine Harbil･Krzysztof Potaczek･Badr-Din Lahmoumi･Pawel Manko･Marcos Carvalho-Barreto (OPmobility)

The world is engaged to reduce CO2 from mobility. Until now, this roadmap has purely focussed on exhaust emissions of greenhouse gases. It neglected the sources of fuels and energy. It also neglected upstream (vehicle production) and downstream (after life) parts of an automotive life cycle. However, an LCA approach is mandatory to truly control and reduce the CO2 footprint of mobility. In this paper we will focus on the upstream and downstream phases. The CO2 emissions of system production and recycling are studied and optimised. In other studies, this is done for yet to produce systems and components. In this study we will take a close look at parts already in the field and reaching the end of their active cycle (vehicle end of life). How can we asses their State of Health? Can they be reused? Can they meet the newest regulations?

[Keynote Address] A Standardized Security Platform for Software-Defined Vehicles: GlobalPlatform Technologies, SAE J3101-5, and the SESIP Certification Framework

Francesca Romana Forestieri･Gil Bernabeu (GlobalPlatform)･Jorge Wallace Ruiz (Dekra)

GlobalPlatform is bringing proven, standardized security solutions—deployed at scale across industries—into automotive, working with OEMs and Tier suppliers to deliver new engineering guidance that directly responds to SAE J3101 Hardware Protected Security Environments. Our work produces: (1) standardized platform architecture and API specifications for isolated execution environments, (2) a Trusted Application model enabling both portable standardized functions and controlled OEM/supplier-specific apps, and (3) SESIP Automotive Security Profiles under development including J3101 components, ECUs, and CMOS image sensors. SESIP adds measurable, reusable certification assets for procurement comparability and reduced late-stage testing. JSAE engagement is invited.

Trusted Execution Environments in Automotive Real-Time Systems

Martin Manthe･Philipp Jungklass･Carolina Pelka･Tim Kaiser･Claude-Pascal Stoeber-Schmidt (IAV)･Dennis Kengo Oka (IAV Japan)･Marco Siebert (IAV)･Shingo Ise (IAV Japan)

Real-time environments demand efficient, resource-saving implementation, especially in automotive systems where cost-optimized control units are crucial. Modern vehicles increasingly rely on networking, online functions, and software updates, raising requirements for secure communication and data storage. Trusted Execution Environments (TEEs) address these security needs. This article explores current TEE approaches, highlighting their advantages and disadvantages, and outlines requirements for future TEEs in automotive real-time environments. It presents a concept that meets these requirements, ensuring secure control units and communication in increasingly connected vehicles, while maintaining efficiency and cost-effectiveness.

Crypto-Agility in Automotive Real-Time Systems in Context of Post-Quantum Cryptography

Carolina Pelka･Philipp Jungklass･Andre Larberg･Nicole Natho (IAV)･Dennis Kengo Oka (IAV Japan)･Tim Kaiser･Claude-Pascal Stoeber-Schmidt･Marco Siebert (IAV)･Takuya Nigoro (IAV Japan)

Quantum computer advances necessitate cryptographic agility, as they efficiently solve asymmetric cryptography problems, requiring algorithm replacement for security. Crypto-agility is crucial for systems receiving software updates over years, like Software Defined Vehicles (SDVs), which expand functionality through software. Resource-limited systems in real-time applications using microcontrollers with hardware-supported cryptographic algorithms face challenges, as hardware accelerators can't be updated. This article presents a concept for updating Electronic Control Units (ECUs) in real-time applications on the AUTOSAR Classic Platform. It implements and evaluates all NIST-standardized post-quantum algorithms on two generations of automotive microcontrollers.

Strategic Aspect of Crypto Agility

Dennis Kengo Oka･Philipp Jungklass･Claude-Pascal Stoeber-Schmidt (IAV)

Cryptographic agility is crucial in the automotive sector due to threats from quantum computers and other factors like increased computing power, vulnerabilities in algorithms, and security bugs. It is a continuous process affecting a vehicle's entire service life, requiring updates to cryptographic algorithms. This article explores cryptographic agility's impact on vehicles, covering phases like development, production, and end customer usage. The focus is on ensuring security throughout the vehicle's lifecycle, adapting to evolving threats and technological advancements to maintain robust protection against potential security breaches.

Cybersecurity for Euro 7
-Requirements, Risks and Technical Solutions for Next-Generation Vehicles-

Dennis Kengo Oka･Claude-Pascal Stoeber-Schmidt･Dustin Woertge･Philipp Jungklass･Steve Peters (IAV)

The Euro 7 regulation imposes stricter vehicle emissions, durability, and data integrity requirements, emphasizing cybersecurity as crucial for compliance. With vehicles relying on interconnected ECUs, secure diagnostics, and on-board monitoring (OBM), protection against tampering and unauthorized access is vital. This paper examines Euro 7 cybersecurity obligations, focusing on anti-tampering, OBM data integrity, secure data transmission, software update security, and alignment with UNECE R155/R156. It highlights threat analysis, secure update processes, and the need for testing and vulnerability assessment of OBM and diagnostic interfaces. We explore regulatory and organizational frameworks and technical solutions to meet Euro 7 security expectations.

Penetration Tests for Guiding Development
-Shift Left Approach for Penetration Tests during Development-

Claude-Pascal Stoeber-Schmidt･Florian Look･Patrick Loster･Dennis Kengo Oka･Takuya Nigoro (IAV)

This paper explores the integration of realistic penetration testing within development timelines, emphasizing the balance between thorough security assessments and project deadlines. It examines the expectations for results, highlighting the necessity for advanced methods, automation, and tools to streamline the process. The study discusses the benefits of early detection of vulnerabilities, which can enhance security and reduce post-release fixes, while also addressing potential disadvantages such as resource allocation and possible delays. By providing insights into effective penetration testing strategies during development, the paper aims to guide developers in optimizing security practices without compromising project timelines.

DMP-SMP Parallel Computation Strategies for FE-BEM-PEM Transmission Loss Simulation in Automotive Dash Panels

Kamel Amichi･Massimiliano Calloni (Keysight Technologies)

Transmission Loss is a key metric for automotive components such as dash panels. While curved panel acoustics are well studied, panels with acoustic treatments receive less attention. Classical FEM and SEA methods are limited by cost and assumptions, and TMM applies mainly to homogenized geometries. Deterministic simulations combining FEM for structure, poroelastic modeling for treatments, and BEM for sound propagation offer greater accuracy. To extend frequency range and enable SEA integration, computation time must be reduced. This paper introduces a DMP-SMP parallel approach for FE-BEM-PEM workflows on trimmed dash panels and compares bare structures using an accelerated H-Matrix BEM solver.

The Study for Improvement of NV Performance by Contribution Analysis of Interior Noise and Optimization of Acoustic Package for Next-Generation BEV

Atsuki Saito･Naotsugu Tajima･Kosuke Ueda･Shoma Taniguchi (HOWA)･Makoto Kon･Kenji Yasuda･Keita Suzuki･Yutaka Yamaguchi (Suzuki Motor)

For next-generation BEV development, a Hybrid Statistical Energy Analysis (HSEA) model was built to conduct contribution analysis of interior noise sources. Based on the result, an optimized vehicle package was designed to enhance NV performance without increasing mass. The validity of this optimization was verified by testing actual vehicle.

Comparison of Conventional Methods and Sound Ray Tracing in Automobile Interior Acoustic Space

Shogo Takeuchi･Kastuhiko Kuroda (Nagasaki Institute of Applied Science)

With the spread of electric vehicles, it has become necessary to address high-frequency noise generated by inverters. Since FEM is generally impractical for acoustic analysis in higher frequency ranges, analytical SEA has traditionally been employed as an alternative approach. However, SEA is not suitable for upstream design due to the time-consuming of its model construction. Therefore, sound ray tracing which has been developed primarily in the architectural acoustics field was applied, and aims to propose a guideline for efficiently balancing the trade-off between computational cost and analysis accuracy in upstream design.

Development of a Method for Predicting Door Closing Sound Sensory Scores in the Design Phase Using CAE and AI

Tomohiro Hori･Koji Morimoto･Kai Fujii･Kana Sugimoto (Daihatsu Motor)･Dirk Von Werne (Siemens Digital Industries Software)･Kohta Sugiura (Siemens)･Yasushi Kido･Genki Matsuno (Skydisc)

Doors are among the most frequently operated components by users, and the closing sound, in particular, is a critical factor influencing the overall impression of a vehicle. However, evaluation of this sound has traditionally relied on physical testing, making it difficult to consider and optimize during the design phase. To address this issue, we have developed a method to estimate sensory scores by inputting spectrograms of door closing sounds obtained through CAE analysis into AI. This approach enables evaluation and optimization of door closing sounds during the design phase, contributing to improved design efficiency and product quality.

Effects of Pure Tone Frequency Arrangement in Inverter Noise on Perceived Unpleasantness

Takuma Kasori･Masahiko Kondo･Masao Yamaguchi･Takeshi Toi (Chuo university)

The sound generated by inverter is composed of multiple pure tone components. This study examined the relationship between masking effects of these components and perceived unpleasantness, focusing on critical bands. It was found that within critical bands, increased dissonance leads to higher levels of unpleasantness. These findings provide practical guidelines for sound quality design of inverters, indicating which frequency position should be avoided to minimize unpleasant auditory perception.

Sound Quality Evaluation by SD Method for Passenger HVAC Noise (2nd Report)

Hideo Takao (Sekiso Corportaion)

In the previous report, we conducted sound quality evaluations of passenger car HVAC noise using the SD method and derived regression equations for subjective evaluations based on loudness and sharpness within the“unpleasant ⇔ pleasant” adjective pairs. We also reported on their practical applicability. In this report, we similarly investigated the relationship between subjective evaluations SD method using other adjective pairs and psychoacoustic metrics, and report on the new findings obtained.

A Proposal of a Musical Score-Based Sound Design Method for Electric Vehicles

Norio Kubo (EV Soundscape)

The quietness of electric vehicles (EVs) has created new demands for both exterior and interior sound design. This study proposes a novel acoustic design method that interprets EV sounds as string-instrument-like phenomena and structures their temporal and frequency characteristics using a musical score-based approach, aiming to achieve a balance between brand expression and safety. First, the contradictory requirements of warning functionality and brand representation inherent in AVAS are examined. Next, we present a method for reconstructing physical and psychoacoustic parameters along a musical time axis. Furthermore, we introduce a design process that bridges AI-based sound quality evaluation (AI-SQ engineering) and creative sound design. For interior sound, we demonstrate how a musical score-based framework can be applied to Active Sound Design (ASD) by analyzing the effectiveness of structured elements such as sound initiation (expectation), development, and transition. For exterior sound, we propose a score-based structural model suitable for AVAS, using the concept sound “Energy” as a case study. These approaches together present a new framework for EV sound design that integrates both functional requirements and emotional value.

Development of a Machine Learning Model for Predicting Engine Noise Perception Considering Temporal Vehicle-State History and Changes in Sensory Stimuli

Shinichi Suganuma (Chuo University)･Shimpei Nagae (Nissan Motor)･Takeshi Toi (Chuo University)

In a previous study using on-road driving data, the highest estimation accuracy was obtained when a 5.5-second time history of engine speed was added to an engine noise perception prediction model that used vehicle parameters as explanatory variables. To clarify the factors that determine this optimal time history window, the present study used a driving simulator in which driving-related external stimulus conditions were varied, including the presence or absence of driving operations and visual information. The influence of these external conditions on the time history window required to achieve maximum prediction accuracy was examined.

Objective Evaluation Method for Interior Sound Quality in Electric Vehicles (First Report)
-Sound Quality Evaluation Method for In-Cabin Electric Powertrain Noise-

Kenji Torii･Kenya Fujii (Honda Motor)

To quantitatively evaluate the sound quality of in-cabin powertrain noise in electric vehicles, a subjective evaluation experiment was conducted with 14 experts using Scheffé's paired comparison method. By analyzing the relationship between the subjective results and psychoacoustic analysis results, key sound quality metrics for electric powertrain noise were identified.

Prediction Method for In-Cabin Powertrain Noise in Electric Vehicles Using Powertrain-Bench Test Data

Kenji Torii･Shion Mise (Honda Motor)･Philipp Sellerbeck (HEAD acoustics)･Kenta Tanabe (HEAD acoustics Japan Co.)

The authors are developing a new NVH design process that utilizes an NVH driving simulator to enhance the interior sound quality of electric vehicles from the early design stage, prior to prototype production. In this study, as part of that effort, three estimation methods for predicting in-cabin powertrain noise were developed using powertrain bench test data based on component-based TPA. Their applicability to the proposed development process was examined and confirmed.

A Study on the Detailed Classification of Vehicle Fuel Pump Noise and Improvement Method for Each Noise Generated

Junghoon Park･Keunsoo Kim･Seunghwan Park･Donghyun Kim (Hyundai Motor)

Noise and vibration have a great influence on the emotional performance of a vehicle. Noise is inevitably generated in the fuel system when the engine of an internal combustion engine vehicle is driven. With the development of sound insulation technology of the vehicle body, the noise from outside of the vehicle has been greatly improved. Therefore, the noise of the fuel system connected to the vehicle body has been highlighted. Elements such as the pump and jet pump of the fuel system as a noise source, and components such as the vehicle body and the fuel tank as noise transfer paths were analyzed. Through this, each noise was classified in detail to find the cause of the occurrence and improvement plan

Vehicle Electrification Effects on the Flow around a Vehicle and Vehicle Dynamics in Running

Kazuhiro Maeda･Mitsuru Sugimoto (Toyota Motor)･Noboru Maeda･Naohito Takasuka (SOKEN)

It is considered that the electrostatic charge generated on a vehicle during driving, combined with environmental conditions and vehicle behavior, affects the vehicle dynamic performance. Efforts are being made to improve this performance by suppressing such variations. Electrostatic effects influence various phenomena; however, this study focuses on countermeasures involving the airflow around the vehicle. By capturing the changes in airflow, motion, and electrostatic charge under these conditions, the effectiveness of the proposed measures was evaluated.

Effects of Electric Forces due to Vehicle Electrification and Air Ions on the Surrounding Flow

Naohito Takasuka (SOKEN)･Kazuhiro Maeda (Toyota Mortor)･Noboru Maeda (SOKEN)

It is considered that electrostatic charging of a vehicle during driving influences its dynamic performance. Improvements focusing on the airflow around the vehicle have revealed changes in its motion, airflow, and electrostatic charge. To understand the mechanism behind these effects, numerical simulations were conducted using a simplified geometry model based on the governing equations of three physical fields—fluid flow, electric field, and charge transport—to clarify how the electric force affects the airflow.

A Study on Quantitative Evaluation Methods for Assessing the Impact of Individual Vortical Flows around a Vehicle on Aerodynamic Drag

Taiga Nonaka･Takuji Nakashima (Hiroshima University)･Yusuke Nakamura (Mazda)･Shohei Imagawa (Hiroshima University)･Keigo Shimizu (Mazda)･Hidemi Mutsuda (Hiroshima University)

In vehicle aerodynamic design, it is desirable to identify and target vortices that have a significant influence on aerodynamic drag among the many vortical flows generated around a moving vehicle. This study combines existing vortex identification techniques with a method for evaluating drag induced by longitudinal vortices. A technique for quantitatively assessing the drag contribution of individual vortices is developed, and its performance is examined.

Development of the Double-Sided Cooler for the Inverter

Masafumi Saito･Yuya Saito･Ryohei Tomita･Tomohiro Shimazu (DENSO)･Yosuke Hasegawa (The University of Tokyo)

For expanding market for HEV and PHEV, we have developed an inverter cooler with high cooling performance that can handle the large current of power modules. The high-cooling performance fin shape contained within the inverter cooler was determined by extracting shapes related to cooling performance and pressure loss from the characteristics of the topology analysis flow, and taking into consideration high-speed press molding for mass production.

Waste Heat Power Generation Using Low Thermal Resistance Thermoelectric Generators

Satoshi Someya･Hiroyasu Mino･Toshie Koyama (Tokyo Denki University)

To improve the thermal efficiency of vehicles with engines, such as hybrid vehicles, waste heat is converted into electricity using thermoelectric power generation devices. The system utilizes refrigerants for air conditioning as coolants to lower the temperature on the low-temperature side, while directing exhaust gases and high-temperature refrigerant flows to the high-temperature side. To maximize heat transfer through the thermoelectric power generation devices while keeping heat confined within the system, devices with low thermal resistance were fabricated and their power generation performance were evaluated.

Artificial Neural Network-Aided Heat Transfer Analysis for Actual Engine Cooling Systems

Takeshi Miyamoto･Shuhei Takamura･Tatsuya Kuboyama･Yasuo Moriyoshi (Chiba University)

This study introduces a novel technique that utilizes an artificial neural network to identify the model parameters of zero-dimensional engine heat balance models. The method was demonstrated through the development of a model for a four-cylinder production gasoline engine.

A Study on the Improving Radiator Performance Prediction Accuracy to Meet Cooling Target

Sangkyu Lee (Hyundai Motor)･Junjung Park (MPSE)

In the conceptual design phase, there often exists a significant discrepancy between the predicted data provided by suppliers and the actual test data for radiators. This issue primarily arises from the limitations of CAE analysis tools, which fail to adequately reflect the specific characteristics of radiators. To address this problem, we have developed a theoretical model that predicts performance based on actual test. Additionally, we have created a user-friendly program that enhances the accuracy and reliability of performance predictions by utilizing a dedicated database.

Development of Control Logic for Preventing Cooling Fan Motor Damage

Taewan Kim (Hyundai Motor)

Heavy rain concentrated during the monsoon season in South Asia is causing damage to cooling fan motors. Operating in a submerged state results in increased load on the cooling fan motor, leading to internal damage due to overload and ultimately causing the motor to fail. This results in engine overheating, and low performance of A/C. To resolve this issue, I aim to reduce field claims by implementing a logic system that detects flooding and restricts operation accordingly.

Standards for Testing and Homologation of Autonomous Driving Vehicles with Digital Twins

Yoshiaki Shoi (ASAM)

In the testing and homologation of automated vehicles, the adoption of a “digital twin” methodology—integrating real-world driving with simulation—is steadily advancing. This paper presents a comprehensive overview of the ASAM OpenX suite of standards, which is fundamental to implementing this methodology, outlining their objectives, expected impacts, and projected developments. Furthermore, the paper examines the underlying approaches to standardization that were developed in conjunction with these specifications.

Applying ISO 21448 (SOTIF) to a Hypothetical Case of Automated Mobility Service

Miharu Oiwa･Yoshihiro Miyazaki･Kazuyoshi Fukuda (JARI)

Currently, there are no publicly available case studies on applying ISO 21448 (SOTIF) to Level 4 automated mobility services, making knowledge sharing difficult. Therefore, this paper presents a case study of applying ISO 21448 (SOTIF) to a hypothetical Level 4 automated mobility service, aiming to provide practical insights to the industry.

Development of a Flexible Head Protection Cap for Bicyclists (Practical Model)

Atsuhiro Konosu･Takahiro Isshiki (JARI)･Kumiko Mori･Asako Fukudumi (Tokushuiryou)･Satoshi Yoshinari (Muroran Institute of Technology)

In a previous study, we proposed a conceptual design for a bicycle head protector that integrated flexibility with shock absorption, aiming to enhance the adoption of protective gear. Building on this concept, the present study focused on practical implementation and successfully developed an improved prototype by refining its appearance—such as adjusting the dimensions of the cushioning material—and incorporating retention features, including a chin strap.

Enhancement of ISO Score Accuracy in Rear-Impact Simulations Using Multi-Objective Optimization

Tomohiro Ueguri (SUBARU)

The introduction of Virtual Testing in crash safety assessments is accelerating, increasing the importance of CAE simulation accuracy. In this study, we developed a multi-objective optimization workflow that leverages whiplash analysis results to evaluate and improve correlation accuracy. Using an optimization platform with machine-learning–based techniques, we explored design-variable combinations that maximize correlation with physical test results. This presentation summarizes the workflow and its effectiveness.

Design, Numerical and Experimental Validation of a Simplified Side Impact Sub-System Test Approach

Alessandro Gravina･Jordi Vinas･Gustavo Maturana･Alba Marquez (Applus IDIADA)

This paper introduces a novel, simplified sub-system test methodology for lateral impact scenarios that offers significant advantages over existing market solutions. Unlike complex alternatives, this effective approach uses an optimized system controlling deceleration, door intrusion, and dummy-interior interactions to replicate the full crash kinematics. Virtual validation at component and sub-system levels precedes physical testing, demonstrating good correlation in pelvis and torso injury metrics, dummy kinematics and SAB deployment. Despite minor intrusion velocity differences affecting shoulder forces, this accessible methodology provides representative crash severity comparable to full-scale tests, enabling efficient side restraint system development from early design phases.

Safety and Effectiveness of the Novel Wheelchair with a Seatbelt System

Masahito Hitosugi･Ayumu Kuwahara (Shiga University of Medical Science)

We developed the novel wheelchair with a seatbelt system. We have confirmed the safety of the wheelchair by sled tests representing a 48 km/h frontal collision with Hybrid III AM50 and AF05. According to driving tests with a welfare vehicle, the time required to board and disembark the vehicle and burden of caregivers were reduced. Therefore, we also confirmed the effectiveness of the novel wheelchair with a seatbelt system.

Injury Analysis of Occupants in Reclining Seated Posture

Tomohiro Izumiyama (Mazda)･Norihiro Nishida･Masahiro Koike (Yamaguchi University)

To reduce fatalities and serious injuries caused by traffic accidents, it is important to maintain proper seating posture and occupant restraint. The seating posture of occupants varies among individuals and affects the restraint provided by seatbelts. In this study, we analyzed the individual variabilities in potential occupant postures and predicted injury risks during collisions using human body models.

Association of Occupant Protection Devices with Maxillofacial Fractures in Frontal Collisions

Hitoshi Ida･Masashi Aoki･Akimitsu Tanaka･Michihisa Asaoka (TOYODA GOSEI CO., LTD.)･Masahito Hitosugi (Shiga University of Medical Science)

Maxillofacial fractures require a prolonged treatment period and cause significant stress to the injured individuals due to postoperative pain and restricted mouth opening caused by intermaxillary fixation, among other factors. This study aims to analyze the incidence of maxillofacial fractures in motorvehicle collisions and their influencing factors using accident investigation databases, and to elucidate effective occupant protection technologies.

Assessment of Carbon-Neutral Scenarios in the Japanese Automotive Sector for the Medium and Long Term

Shuichi Kanari･Hiroshi Hirai･Takaaki Kitamura (JARI)

The Japanese government has announced its commitment to achieve carbon neutrality by 2050. It has introduced measures such as medium-term CO₂ reduction targets, updated fuel efficiency standards, and the 7th Strategic Energy Plan. The authors conduct scenario analyses based on the 7th Strategic Energy Plan and, using the results, estimate CO₂ emissions and related factors such as energy consumption, fuel economy, and rare metal use from the automotive sector in 2050.

Study on CO₂ Reduction by Improving Traffic Flow

Hayato Shirai･Takashi Nishikiori･Kizuku Yamada･Yoshiyuki Kageura･Tomomi Yamada･Toshiya Hashimoto (Toyota Motor)

To estimate the CO₂ reduction effect of improving traffic flow on expressways, a traffic flow simulation was designed and validated to reproduce individual vehicle behaviors, and was coupled with fuel consumption simulations for passenger cars and heavy-duty vehicles. On multi-lane sections, narrowing the speed range within lanes reduced the frequency of lane changes and acceleration/deceleration, quantitatively demonstrating a decrease in total CO₂ emissions.

Development of Operational Architecture for the Automated Driving Minibus Undergoing Demonstration Testing in Shiojiri City

Mitsuaki Nakada (Magna Electronics Japan)･Kazuyuki Murakami (Gentex Japan)･Takamasa Arata (Magna Electronics Japan)･Yukihiko Akaike (T2)･Ryohei Kawabuchi (Tier IV)･Yuichiro Abe (Dassault Systemes)･Katsutoshi Yokoo (Siemens)･David Hetherington (Asatte Press)･Hidekazu Nishimura (Keio University)

In this paper, we investigate the operational architecture needed for the automated driving minibus being validated in Shiojiri City. In order to fully understand the needs and requirements for the minibus, we use the Unified Architecture Framework to describe the regional digital transformation strategy of Shiojiri City and to derive the needs and requirements for defining the vehicle architecture of the minibus.

Universal Mobility Equation: Quantifying Mobility Index

Taehee Lee･Dae-Un Sung (Hyundai Motor)

This paper proposes a universal mobility equation to quantify movement capability for biological and artificial agents. Inspired by the Drake Equation, the model integrates physical power, environmental constraints, structural mobility, technological support, social authority, purposefulness, and time. Comparative analysis using humans, drones, and AI robots demonstrates how these factors interact to shape mobility potential. The framework enables interdisciplinary evaluation and simulation, offering insights for future mobility concepts, intelligent agent design, and mobility inequality studies.

An Analysis of Performance Trends in the Replacement Tire Market Following European Automotive Environmental Regulations

Jeongin Seo･Youngseok Jang･Ghiyoun Lee (Hyundai Motor)

In Europe, environmental regulations for vehicles have become increasingly stringent. These regulations directly impact tires, targeting key performance indicators such as rolling resistance and external noise. As a result, vehicle manufacturers are setting higher development targets for their tires. However, as tires are consumable products, they require periodic replacement. Therefore, it is necessary to verify whether the performance of replacement tires in the consumer market is keeping pace with these stricter regulations. For this study, data on commercially available tires were collected from the consumer market over a four-year period. The results show that the average rolling resistance of replacement tires improved by 11%, while noise levels remained stable. Additionally, the market share of tires with a larger outer diameter increased by 13.7%. This improvement in rolling resistance can likely be attributed to Regulation (EU) 2019/631.

IRIS - IDIADA's Regulatory Information System
-Managing Regulatory Complexity of Global Automotive Legislation-

Maria Jose Asensi･Enric Porta･Nagore Aviles･Pietro Lumare (Applus IDIADA)

IRIS is a powerful digital platform that delivers structured, reliable, and up-to-date regulatory technical knowledge for the automotive industry. Developed by Applus+ IDIADA's Homologation department, IRIS provides permanent access to worldwide vehicle regulations and offers a seamless, user-friendly experience designed to support certification teams, regulatory experts, and automotive professionals in their daily decision-making. Permanent access to 4,000+ up-to-date worldwide automotive industry regulations Dynamic and customizable Regulatory Technical Attributes Comparison Tool First-hand interpretations on automotive industry laws and regulations Participation in the rulemaking process Dynamic timeline tool with integrated filters With more than 4,000 current and upcoming global regulations available, IRIS ensures users always have the right information at the right time, all within a unified and intelligent interface.

The DCAS Bridge
-Understanding Regulatory Progression from Traditional ADAS to Full Automotive Automation-

Carlos Lujan･Oriol Flix･Nadia Martinez (Applus IDIADA)

The automotive industry is experiencing evolution in driving automation systems, necessitating comprehensive understanding of regulatory progression from Advanced Driver Assistance Systems (ADAS) under UN Regulation No.79 to Driver Control Assistance Systems (DCAS) per UN Regulation No.171, and ultimately to Automated Driving Systems (SAE Levels 3-5). This paper analyzes this evolutionary pathway, emphasizing DCAS as critical bridging technology between current ADAS and autonomous vehicles. The study examines regulatory distinctions differentiating automation levels, focusing on paradigm shifts in driver responsibility and system accountability. Research identifies regulatory framework gaps and proposes harmonization recommendations, addressing verification and validation challenges for automated vehicle deployment.

Beyond Four Wheels: UN Regulation No. 155 Implementation in Light Mobility Vehicle Cybersecurity

Carlos Lujan･Oriol Flix･Nadia Martinez (Applus IDIADA)

UN Regulation No.155 represents a pivotal advancement in automotive cybersecurity, establishing mandatory vehicle protection frameworks. This paper analyzes its adaptation to light mobility vehicles—motorcycles, tricycles, and quadricycles—undergoing rapid digital transformation through connectivity and assistance systems. Light vehicles face unique cybersecurity challenges: limited computational resources, space constraints, and distinct threat vectors from exposed rider interfaces. Manufacturer CSMS implementations vary significantly, particularly in threat assessments for handlebar displays, navigation systems, and vehicle-to-vehicle communications. Research examines regulatory evolution, manufacturer compliance strategies, and certification adaptations. Findings highlight the regulation's flexibility while identifying needs for vehicle-specific guidance in updates and supply chain management.

Challenges and Solutions to EU Battery Passport Regulation Compliance for Asian Economic Operators
-Regulatory, Architectural, and Cybersecurity Requirements for Digital Battery Passport Implementation-

Subhajeet Rath･Sjoerd Rongen･Avedis Dadikozyan･Erik Hoedemaekers･Steven Wilkins (Nederlandse Organisatie voor Toegepast Natuurwetenschappelijk Onderzoek (TNO))

This paper examines the practical and technical challenges Asian economic operators face in complying with the EU Battery Passport regulations. It analyzes high-level regulatory implications and outlines optimal IT/IoT architectures for capturing and managing battery lifecycle data. Key concerns such as data access, interoperability, cybersecurity and dynamic synchronization between the Battery Management System (BMS) and cloud platforms are addressed. Based on findings from pilot demonstrations, the paper provides recommendations for collaborative solutions within the battery ecosystem to ensure a scalable, regulation-compliant implementation of battery passports.

Methodology of Scale Model Experiment for xEV Fire Torture Standard Test

Shuhei Yasuda･Risa Asada･Junichi Ogawa (Mazda)･Kohei Kajitani･Satoshi Enokida･Atsushi Yuki (Daikyonishikawa)･Masayuki Okoshi (Gifu University)･Yuji Nakamura (Toyohashi University of Technology)

Fire safety tests for rechargeable electric vehicles require the use of actual vehicles or battery packs, resulting in significant time and cost. In this study, to improve the efficiency of xEV fire safety design, we investigated a small-scale model testing method for the fire exposure standard test. A scale model applying Froude number similarity was evaluated through both simulation and experiment.

Study on Ventilation Volume of EV in the Case of Transport for COVID-19 Patient (Part5)

Koichi Oshino (non)

Cabin ventilation is important in the case of transport for COVD-19 patients. At the previous report, it was obtained the relation between small opening window height and the ventilation volume. It is predicted that the vehicles have the satisfied ventilation volume on the outside air inducing method at the previous report. Here, I would like to submit following two methods. First one is the ventilation of the outside air inducing method, second one is that of the small opening window height method.

A Study on Driving Safety Funtions and Field Data Usage Method

Suho Lee･Seongho Song･Seungwan Cho･Jinho Kim (Automotive R&D Division of Hyundai Motor Group)

The purpose of this study is to protect the safety of customers when driving a vehicle by developing a function that monitors vehicle data and provides a warning in advance when an abnormal situation occurs. Data collection devices and diagnostic logic were developed for older vehicles that cannot collect data. For example, a lack of coolant in a vehicle and a vehicle accident diagnosis logic have been developed and evaluated, and this function can be applied to older vehicles to upgrade their safety functions. Then I propose logics for calculating safe driving scores and the failure of the coolant temperature control apparatus that using the data stored in the cloud. When a customer diagnoses an abnormality in the vehicle early and provides notifications and services before experiencing inconvenience, It is believed that it will contribute to accident prevention by providing a safer mobility environment and service.

Driving the Future: Accelerating Vehicle Development Speed through Cross-Industry Synergies

Bernhard Raser (AVL List)･Toru Nishizawa (AVL Japan)･Laura Kraihamer･Johannes Linderl (AVL List)

Electrification, connectivity, and sustainability are driving unprecedented time-to-market pressure for modern vehicle development. Passenger cars, commercial vehicles, and off-road applications share similar challenges, yet often develop solutions in isolation. This paper demonstrates how cross-industry learning, combined with digitalization and model-based systems engineering, can significantly accelerate development speed. Scalable simulation, virtual validation, and AI-driven optimization enable early design decisions and reduce physical testing. Examples of AVLs proven development chain demonstrate how established methods in one domain can be adapted to others, creating a continuous feedback loop of innovation. Standardized interfaces and integrated tools further support global collaboration, ensuring quality and compliance while meeting sustainability targets.

Leveraging the Safety Concept Description Language (SCDL) for Harmonized Development of SOTIF and Functional Safety

Nobuaki Tanaka (OTSL)･Akira Takada･Shuhei Yamashita･Misako Imai (DNV Business Assurance Japan)･Toyokazu Ogasawara (Ota Development Efficiency Project)･Tomoyoshi Murata (JARI)･Kiyoshi Sasaki (Astemo)･Hideaki Nishihara (AIST)

This paper proposes a design methodology that applies the SCDL, Safety Concept Description Language, and the SRVA, Safety Requirement Violation Analysis, to SOTIF, ISO 21448, development. The approach enables progressive refinement of requirements and their allocation to system elements, similar to functional safety processes. Its applicability is demonstrated through a case study involving the representation of a SOTIF architecture for an automated driving system.

A study of ADS Safety Assessment Methodology using Near-Miss Data on Logistics Trucks

Shoji Ito･Hideo Inoue･Yasuhiko Nakano･Kenichi Uehara･Aekanan Sakulraemrung (Kanagawa Institute of Technology)･Hiroshi Fukuda (BIPROGY Inc.)･Mototsugu Miura (PTV Group Japan Ltd.)

METI (The Ministry of Economy, Trade and Industry)'s Digital Lifeline Project established a safety assessment methodology utilizing simulations with generating risk scenarios from near-miss images captured by approximately 400,000 km of logistics trucks,. This paper describes a series of foundational technologies: the categorization of near-misses, the configuration methods for agent driver models and traffic flow reflecting risks, and evaluation metrics for severity and exposure.

Effectiveness Testing of ADAS in the PTI (Periodical Inspection Test)

Andreas Himmler･Patrizio Agostinelli (dSPACE)･Hiroki Hanaoka (dSPACE Japan)

Mandatory installation of important ADAS functions is being promoted in many countries. However, ADAS are not subjected to regular inspections or functional tests even the legally mandated. On the one hand, there are no legal requirements, and testing methods and equipment are not yet available. In this presentation, the options discussed in the EU for such test methods and the functional principles and developing status of the associated test equipment will be discussed.

Resilient and Continuous Safety Assurance Methodology for CCAM and its HMI Components

Oana Moldovan (Applus+Idiada)

The CERTAIN project develops a comprehensive Safety Assurance Framework (SAF) for Cooperative, Connected, and Automated Mobility (CCAM) systems, emphasizing resilience, human-centric design, and continuous assessment. The methodology combines real-world with virtual validations, incorporating stakeholder needs, AI trustworthiness, human-machine interactions and V2X connectivity. The framework ensures ongoing safety through in-service monitoring and reporting, including handling over-the-air updates. Multiple use cases across different vehicle types, from passenger cars to trucks, and automation levels (L2-L4), validate the approach, focusing on safety, trust, user acceptance and comfort. This holistic approach aims to facilitate safe, reliable deployment of CCAM systems with industrial and regulatory consensus.

Automatic Generation of Training Data for Long-Range Nighttime Recognition Using a Long-Baseline Stereo Camera

Shunya Kumano･Shoji Matsuzaka･Nao Ikeda･Yumi Yamada･Yusuke Ueda･Naoki Kawasaki (SOKEN)･Kiichiro Kawakami (Toyota Motor)

Creating training data required for long-range nighttime recognition involves substantial manual annotation work on development-camera images. In this study, we propose an automatic annotation technique that accurately aligns results detected up to approximately 1 km by a 90-cm baseline stereo camera to development-camera images using a calibration-based two-stage processing method, achieving approximately 90% reduction in labor.

Scenario Extraction from Drive Recorder Footage for Traffic Scene Retrieval

Masafumi Tsuyuki (Hitachi)･Tetsuya Nishida･Taminori Tomita･Yoshitaka Atarashi (Astemo)

Enhancing the development efficiency of Advanced Driver Assistance Systems (ADAS) requires robust video retrieval methods. However, comprehensively addressing diverse retrieval requirements remains a significant challenge. This study introduces a scenario-based retrieval approach that leverages the capability of driving simulators to reproduce arbitrary traffic scenes. The proposed method extracts scenario definitions exclusively from monocular camera footage and positional data, enabling structured and searchable representations. By facilitating efficient access to relevant driving situations, this approach supports systematic evaluation and accelerates the development of advanced driver assistance technologies.

A New Method for Forward Parallel Parking Assistance Using Rear-Wheel Steering

Kenta Maeda (Hitachi)･Tatsuya Shiraishi･Daisuke Tsuga･Hiroki Ishimaru･Miki Koso･Atsushi Yokoyama (Astemo)

Parallel parking is one of the driving tasks with which many drivers feel uncomfortable. With conventional front-wheel steering, drivers are forced to reverse when parallel parking; however, introducing rear-wheel steering enables forward parking. This presentation proposes a new method that applies in-phase rear-wheel steering when the parallel parking starts, in contrast to the conventional counter-phase (opposite) rear-wheel steering, aiming to reduce driver anxiety.

A Study on Road Traffic Flow Enhancement with Optimized ACC Strategies

Yoshiaki Irie･Tomoaki Morimoto (Toyota Motor)

Anticipating the widespread adoption of AD/ADAS, this study explores ACC control methods beyond the conventional focus on occupant safety and comfort. By analyzing the detailed behavior of individual vehicles on urban highways, we investigate strategies to optimize ACC operation for smoother traffic flow, contributing not only to individual vehicle performance but also to overall traffic efficiency.

Development of a Non-Contact In-Vehicle Human Presence Detection Sensor Using Spatial Potential Fluctuations

Kenji Kouno (The University of Tokyo)･Hiroyuki Suto (Toyota Motor)･Yusuke Yokota (The University of Tokyo)･Yusuke Umetani (Toyota Motor)･Yoshihiro Suda (Tokyo University of Technology)

This study proposes a non-contact human detection method that captures in-vehicle potential fluctuations caused by body motion and breathing using a passive sensor. Although the sensor can be implemented with a simple configuration based on a field-effect transistor, its noise tolerance has been limited. We developed an improved sensor that achieves higher SNR than conventional sensors and supports wired integration with in-vehicle systems.

Design and Implementation of a Tire Force Estimation Model Based on the Extended Kalman Filter

Shota Kitano･Hideki Itoga･Takanori Hibino･Kazuki Kuwabara･Hirotaka Kaneko･Tomotaka Sugai (Toyota Motor)

From our previous report, it was found that combining an 8-degree-of-freedom vehicle model with an Extended Kalman Filter enables highly accurate estimation of tire forces. However, there is no clear method for determining the system covariance QQQ and observation covariance RRR, which significantly affect the accuracy of the Kalman Filter, and this topic generated considerable discussion during the Q&A session. In this presentation, we propose a method for determining QQQ and RRR by applying an optimization approach that utilizes the estimation error covariance and the observation prediction error covariance, thereby achieving sufficient accuracy.

Influence of Coupling Engagement Level in an Electronic AWD System on Planar and Vertical Vehicle Dynamics

Naoki Hiraga･Koki Yamamoto･Daichi Okazaki･Osamu Sunahara (Mazda)･Katsuya Ishii･Makoto Yamakado･Yoshio Kano･Masaki Yamamoto･Masato Abe (Kanagawa Institute of Technology)

In AWD vehicles equipped with an electronically controlled coupling, torque is transmitted through rotational constraint between the front and rear axles according to the level of longitudinal differential limiting generated by the coupling engagement. This mechanism influences the planar motion and the sprung-mass behavior of the vehicle. In this study, these effects are analyzed, and the effectiveness of a coupling control strategy coordinated with G-Vectoring Control is verified.

Influence of Assistive Brake G-Vectoring Control on Double Lane-Change Test Performance

Haruki Majima･Ibuki Genpei･Masato Abe･Yoshio Kano･Masaki Yamamoto･Makoto Yamakado (Kanagawa Institute of Technology)･Tomohisa Shibata･Yoichi Mizuno (Toyota Motor)

The influence of Brake G-Vectoring Control on double lane-change test performance was evaluated. Full-scale tests based on ISO 3888-2 (elk test) were conducted, and differences in passing speed, steering operation, and vehicle motion with and without the control were compared. Improvements such as enhanced initial yaw response, contributing to a more intuitive steering feel(INOMAMA-KAN), were observed, indicating factors through which the control contributes to performance enhancement.

Development of AI-Based Bush Characteristics Prediction Model for R&H Simulation Modeling Efficiency

Mireu Kim･Taemin Jeong (Hyundai Motor)

Recently, as AI technology has advanced, attempts to incorporate AI technology into the vehicle modeling process in the CAE field have increased. Previously, the static or dynamic characteristics of vehicle parts were expressed in the form of mathematical functions and substituted with equivalent models. However, this type of modeling technique has limitations in expressing the complex nonlinear dynamic characteristics of vehicle parts. Therefore, this paper proposes a new modeling technique by introducing AI technology to the existing modeling technique and shows that the efficiency of vehicle parts characteristic modeling can be improved.

Energy-Transmissibility-Based Transient Response Analysis of Vehicle Dynamics

Toru Yamazaki･Atsushi Kosegawa･Yudai Araki (Kanagawa University)

This study extends a previously proposed energy transmissibility model from steady-state to transient vehicle dynamics. A three-degree-of-freedom model, consisting of lateral, yaw, and roll motions, is reformulated in the time domain so that power input, transfer, and dissipation can be tracked during maneuvers. Step and pulse steering inputs, as well as roll disturbances, are applied to evaluate the transient evolution of slip-angle, yaw-rate, and roll-energy states. The results clarify design trade-offs between agility and stability, linking steady and transient behavior, and illustrate how energy-based indices can guide early-stage tuning of mass, damping, and steering characteristics.

Design of an Integrated Steering-Suspension Corner Module

Haoyang Lyu･Jianyuan Liu･Jingran Wang･Kaipeng Wang･Hongyuan Jiang･Zihong Zou･Zhouyi Zhen･Mingyan Hu･Mengjian Tian (Shenzhen Technology University)

The steering–suspension design of electric-drive corner modules faces an inherent kingpin parameter conflict: increasing scrub radius for high maneuverability compromises steering lightness and brake stability. This hinders simultaneous high maneuverability and high-speed stability. To address this, a novel dual-kingpin, two-stage integrated suspension steering mechanism is proposed. The primary kingpin is determined by a multi-link suspension, and the assembly, mounted on a supporting component, steers about the secondary kingpin via a crank-rocker linkage. ADAMS/Car simulation validates that the mechanism effectively balances large-angle maneuverability with high-speed stability.

Effect of Measurement Method Differences on the Evaluation of Tire Lateral Relaxation Length

Taichi Murakami･Akio Uesaka･Naohiro Ishigami･Hiroshi Nashio (TOYO TIRE Corporation)

In the development of vehicle dynamic performance, tire relaxation length is considered an important characteristic. Conventionally, several methods for measuring relaxation length have been proposed. This study describes a comparison of four methods—sinusoidal input, step input, ramp-step input, and predicted method based on the ratio of the cornering stiffness and the lateral structural stiffness, and examines the differences and underlying factors.

Development of in-Tire Inflation System for Controlling Tire Dynamic Characteristics

Masami Matsubara (Waseda University)･Naoki Sekino･Junya Tanehashi･Daisuke Yokoi (Suzuki Motor)

This study developed a system that enables controlling of tire inflation pressure during vehicle driving. This system consists of the high-inflated tube embedded in tire and controlling device of inflation pressure. In this presentation, we will present the development process of this system and the effect on tire dynamic characteristics.

Improvement of Output from Triboelectric Nanogenerator in Intelligent Tire

Hiroshi Tani･Renguo Lu･Shinji Koganezawa (Kansai University)･Jun Matsuda･Tadashi Higuchi･Shigeki Hayashi (Yokohama Rubber Co.)

We improved the output of the triboelectric nanogenerator mounted into the intelligent tire. By optimizing the triboelectrification film and the generator's dimensions, we achieved an output level of approximately 8 mW at 80 km/h.

Experimental Investigation of Acceptable Latency from the Perspective of Driving Operability in Vehicle Driving Simulators

Takeshi Yoshida･Takayuki Aoki･Daisuke Itagaki･Hirotaka Sakamoto･Tsubasa Oguro (Toyota Motor)

This study investigates acceptable latency thresholds in driving simulators from the standpoint of driving operability. To assess the impact of in-vehicle device communication and network latency, two types of delays—display latency and force feedback (FFB) latency—were independently evaluated. A panel-based evaluation using a physical simulator was conducted under various delay conditions. Sensory indicators related to driving operability were analyzed using a multivariate Bayesian hierarchical ordinal logistic regression model. The study established a method for evaluating perceived latency and quantified the contribution of display latency, FFB latency, and reaction force to the overall sense of delay.

A Case Study on the Reliability of Online Driving Aptitude Assessment for Older Drivers
-Study on Driver Characteristics for Delaying Driving Cessation (48)-

Shunji Taniguchi･Aiko Inoue･Hiroyuki Umegaki (Nagoya University)･Naoshi Koide (Osaka University)･Hirofumi Aoki (Nagoya University)

This study investigated the reliability of online driving aptitude assessments for older drivers. Participants completed both online assessments and university-based measurements. Items included grip strength, the Trail Making Test (TMT), the Multi-Stimulus Vision Tester (MVT), and the Hazard Perception test (HP). Online and laboratory results showed partial discrepancies for grip strength, TMT, and HP, but overall correspondence was confirmed, indicating that calibration could enhance online reliability. In contrast, MVT showed limitations in online use, requiring additional conditions. Despite these constraints, the findings suggest that online assessments remain a useful and practical tool for simplified evaluation of older drivers.

Maintaining Driver Alertness and Suppressing the Decline in Thermal Comfort Through Thermal Stimulation Inside the Vehicle

Rina Nibe･Takuya Kurimoto･Koji Notake (Nissan Motor)･Jongseong Gwak (Takushoku University)･Akinari Hirao (Shibaura Institute of Technology)･Motoki Shino (Institute of Science Tokyo)

Maintaining driver alertness using conventional alarms often leads to reduced comfort. To examine whether thermal stimulation through air conditioning can achieve both comfort and alertness maintenance, We conducted experiments using both an actual vehicle and a driving simulator (DS) to obtain subjective evaluations and eye-closure rates. The results demonstrated that under conditions with stimulation, alertness was maintained without compromising comfort.

Development of a Controlled Testing Procedure for Evaluating Driver Alcohol Intoxication Detection Systems

Francesco Deiana･James D. Jackson･Simone Toma･Cristina Periago Linares (APPLUS+ IDIADA)

This work presents a controlled testing procedure for evaluating driver alcohol intoxication detection systems. With increasing regulatory and consumer safety pressure to address alcohol-impaired driving, there is a clear need for validated methodologies involving real human subjects. The proposed approach enables safe, standardised testing at low to moderate intoxication levels, conducted in both simulator and proving ground environments. It supports the collection of behavioural and physiological indicators necessary to assess system effectiveness. This methodology fills a critical gap between lab-based validation and real-world deployment in the development of automotive safety technologies.

A Study on Optimal Operating Force of Automotive Moving Parts Based on Muscle Activation and User Perceived Effort

Jaehoon Chung (Hyundai Motor)

This study aims to propose an ergonomic guideline for optimal operating force in automotive moving parts specifically doors and tailgates by analyzing both the user's physical load and subjective perception of discomfort. Unlike traditional design approaches , this research adopts a human-centered perspective by quantifying upper-body muscle activation using surface electromyography (EMG) and evaluating user-perceived discomfort during opening and closing operations. The results demonstrate that as operating force increases, both muscle activation and perceived discomfort rise correspondingly. Based on these findings, optimal operating force guidelines were established to satisfy two critical criteria: acceptable levels of muscle activation and minimal user discomfort. The threshold for muscle activation was determined with reference to prior ergonomic research, defining an upper limit that permits physical effort without inducing excessive fatigue.

Effect of Acceleration and Deceleration Characteristics of Electric Vehicles on Pedal Operation of Elderly Drivers

Yusuke Hayashida (Tokyo University of Agriculture and Technology)･Tatsuya Iizuka･Akihiro Abe･Yoko Kato･Michiaki Sekine (NALTEC)

Electric vehicles exhibit larger acceleration and deceleration responses to accelerator pedal inputs than gasoline-engine vehicles. Therefore, elderly drivers accustomed to gasoline-engine vehicles may have difficulty operating them properly. In this research, a driving simulator was used to recreate a scenario in which a vehicle follows a preceding vehicle, and the pedal input and vehicle behavior of elderly drivers operating electric vehicles were evaluated using various evaluation indicators.

Regional Differences in Collision Avoidance Emergency Braking Frequency Measured by Dashcams of Elderly Drivers
-Study on Driver Characteristics for Delaying Driving Cessation (47)-

Takashi Yonekawa･Hirofumi Aoki (Institute of Innovation for Future Society Nagoya University)･Kan Shimazaki (Kindai University)･Masae Kojima･Rin Itou･Akio Hirano･Sueharu Nagiri (nstitute of Innovation for Future Society Nagoya University)

The previous report confirmed a correlation between collision avoidance emergency braking frequency per driving distance measured by elderly drivers' dashcams and their safe driving ability. This report compares collision avoidance emergency braking frequencies in the Nagoya and Tsukuba regions, which have different driving environments. Since the frequency was lower in the Tsukuba region, we propose a method for evaluation using collision avoidance emergency braking frequency adjusted for driving speed.

Estimation of Driving Style Based on Eye Tracking During Autonomous Driving

Yuki Mekata (Kanagawa University)

Personalizing the controls of a driving assistance system is expected to encourage drivers to use the system appropriately. This study attempted to estimate drivers' style in their braking operations based on eye tracking data corrected during autonomous driving using a driving simulator. The realization of such estimations is expected to expand the feasibility of personalization in driving assistance systems.

Driving Simulator Log Analysis in Rehabilitation for Resuming Driving

Chise Kobayashi (Kindai University)･Ryunosuke Hashimoto (Kishigawa Rehabilitation Hospital)･Takeshi Kohama (Kindai University)

To establish objective criteria for assessing the feasibility of driving resumption in patients with brain injury, driving behavior was analyzed using log data obtained during rehabilitation using a driving simulator. We compared three groups: healthy individuals, those who resumed driving, and those who did not. The findings indicated differences in driving behavior among the groups during steering maneuvers when vehicles approached from the right side.

A Study on the Causes of Diesel Injector Claims in India through Low-Pressure Fuel System Analysis

Keunsoo Kim (Hyundai Motor)

This study analyzes the causes of diesel injector claims in the Indian market from the perspective of the low-pressure fuel system and fuel characteristics under low-temperature conditions. Injector claim rates exceed 1%, predominantly occurring in northern regions with harsh winters. Investigations reveal that fuel filter internal leakage caused by paraffin crystallization and structural weaknesses leads to injector malfunction. Comparative chamber tests confirmed filter leakage in specific filter types under cold conditions. Field tests in mountainous northern India supported these findings. Recommendations include structural improvements and heater application to mitigate leakage. This research contributes to enhancing diesel injector reliability in challenging climates.

Development of a Multi-Component Surrogate Model for Biodiesel Fuel

Sho Fukuda･Takashi Kawachi･Koji Momose (Toyota Industries)･Hideki Takase (IDAJ)･Tomohiro Hayashi･Toshiaki Hijima (SOKEN)

A multi-component surrogate model for biodiesel fuels was developed by separating liquid-phase and gas-phase surrogates based on actual fuel composition. This approach avoids complex conversion methods while preserving key reaction characteristics. The model integrates detailed chemical kinetics into CFD simulations and is validated against engine experiments, accurately predicting ignition delay, heat release, and emission trends. This method offers a practical tool for combustion and emission analysis across diverse fuel types, supporting carbon-neutral engine design.

Alcohol Diffusive Combustion Technique as an Alternative Diesel Combustion Fourth Report
-Effect of Reducing Diesel Fuel Fraction in Dual-Fuel Injection-

Yoshifumi Wakisaka･Teruaki Kondo･Kazuaki Nishikawa･Takayuki Fuyuto (Toyota Central R&D Labs.)･Kenji Date･Yusuke Ueda･Satoshi Sugawara (DENSO)

Alcohol fuel, namely methanol and ethanol, are promising fuel for diffusive combustion in heavy-duty diesel engines, while they are difficult to self-ignite. In this study, a prototype dual-fuel injector that injects diesel fuel as an ignition source from the same nozzle with ethanol was developed. By installing a small orifice into the diesel flow path and reducing the diesel proportion during the main injection, we demonstrated that smoke can be significantly reduced even under medium-load conditions where the diesel proportion is relatively high.

A Study on Factors Affecting Water Evaporation from Emulsified Oil in a Hydrogen Engine

Akemi Ito･Ryosuke Ichimura･Itsuki Motomiya (Tokyo City University Engine Research Laboratory)

Hydrogen engines produce more water than conventional fossil fuel engines, making oil emulsification more likely during winter operation. It was shown in authors' previous report that factors such as oil temperature and liquid surface area affect the evaporation of water from emulsified oil. This paper reports on the results of a new investigation into the effects of humidity and container shape, evaluating the contribution of each factor to the evaporation of water using multiple regression analysis.

Predictive Technology for Engine Oil Adhesion as the Core of Intake-System Engine Deposits

Aiko Kawakami･Shinichi Tanioka･Yoichi Kuji (mazda)

This report presents the results of testing the oil-repellent and slip properties between engine oil and the substrate using molecular dynamics and particle methods. By applying molecular dynamics methods, a desk-based verification model was developed to predict the tendency of engine oil mist, which triggers deposit buildup on intake system components, to adhere. This enabled the selection of coatings effective in suppressing adhesion and the consideration of formulations for engine oil additives.In addition, the behavior of oil mist was visualized using the particle method, and the validity of the adhesion suppression effect was examined.

Modeling Running-In Process of Engine Bearings with Roughness Evolution and Tribo-Film Effects

Kentaro Kawaguchi (Mazda)

Engine bearing friction characteristics change during operation as running-in progresses. Running-in is governed by coupled processes across scales, including surface geometry evolution, roughness changes, and tribo-film formation. Thus, it is difficult to model and often understood only empirically. In this study, we develop a model that simultaneously accounts for roughness evolution and tribo-film effects, enabling quantitative prediction of the bearing running-in process. The proposed approach offers improved interpretability of running-in mechanisms and provides a basis for rational design of sliding surface performance.

Investigation of Piston–Ring Dynamic Mechanisms Governing Ring Sealing and Flutter Analysis Technology

Junjiro Nakanishi･Kouji Shishime･Masaki Fukuma (Mazda)

In this study, the relationship between piston secondary motion and ring flutter was clarified using a model whose prediction accuracy for ring behavior had been validated. Furthermore, it was demonstrated that piston secondary motion affects land pressures and thereby contributes to the onset of flutter.

Development of a Hydrogen Engine for Light Commercial Vehicles

Ryosuke Matsui･Tomihisa Tsuchiya･Michito Shirakawa･Taketo Nagasaki･Toru Sakuma･Satoshi Ido･Yasuhiro Haruna･Kazuya Nakata (Toyota Motor)･Akihiro Ando (SOKEN)

To promote hydrogen adoption, we developed a hydrogen engine for light commercial vehicles. Based on a V6 3.5L turbocharged gasoline engine, over 90% of parts were reused while achieving 40% thermal efficiency and meeting Euro 7 emission standards. This presentation will address technical challenges such as abnormal combustion caused by hydrogen and the solutions implemented.

Development of Ammonia/Hydrogen SI Engine
-Impact of Port Fuel Injection Applied to the Ammonia/Hydrogen Fuel Supply System on Engine Performance-

Naoki Muta･Kosuke Kusaba･Hiroaki Masatsuki･Tomohiro Nishihashi･Tomonori Kuroki･Yukihide Nagano･Masato Sawashita･Yuta Shima･Kazuya Naito･Tatsuya Ehara (Daihatsu Motor)

The ammonia/hydrogen spark ignition engine will be developed as one of the engines using the carbon-neutral fuel. This study aims to evaluate the impact of adopting a port fuel injection (PFI) system for the supply of an ammonia/hydrogen mixture on engine performance. Building upon the direct-injection (DI) hydrogen jet model developed in our previous work, a new PFI jet model was formulated. Engine simulations and performance assessments were conducted for the PFI-based supply system.

Combustion Studies on a Large-Bore Pent-Roof Spark-Ignited Hydrogen Engine

Thomas Briggs･Daniel Ryan Williams (Southwest Research Institute)･Tomoyuki Itou (Isuzu Motors)

A pent-roof combustion chamber design was adapted from a previous natural gas engine demonstration to allow for single-cylinder engine combustion studies on PFI and LPDI hydrogen operation. Comparisons were made of the impact of tumble and injector type on the efficiency and performance of this engine. The results demonstrated an improvement in efficiency for LPDI relative to PFI and that tumble ratio did not have a strong impact on hydrogen combustion. Peak net indicated thermal efficiency of 46% was measured, with engine-out NOX emissions and engine out exhaust temperature at levels which are compatible with standard lean-NOX aftertreatment solutions.

Ultra-High-Efficiency Production Technology for Mass Production of 2nd-Generation Fuel Cell Systems
-(First Report)-

Nobuyoshi Muromoto (Honda Motor)

In the second-generation fuel cell system, Honda successfully established a scalable high-volume manufacturing system for fuel cell systems. By consolidating production engineering expertise cultivated through previous in-house models development, Honda launched its first mass production of fuel cells in North America. Key innovations—such as the consolidation of electrode rolls into 2 rolls, integration of MEA manufacturing processes, and complete automation of cell stack assembly—enabled substantial labor reduction, improved utilization of high-cost materials, and the shift away from operator-dependent processes. These achievements transformed the manufacturing capability into a robust production platform designed for future business expansion.

Analytical Study for the Effective Induction Heating Welding of the Steel Pipes

Tomohiko Ariyoshi (Atori CAE)

Induction heating welding is the effective method for bonding pipes. But according to the temperature distribution on the connecting surfaces, the deformations tend to bear irregular shapes. This article describes the analytical study results on the highly efficient induction axial welding of the steel pipes.

Visualization of Residual Stress Generation Process in Press-Formed Parts through Coupled FE Analysis of Shearing and Forming Using Solid Elements

Hitoshi Ikeno･Takanori Miwa･Hiroki Yokoyama･Yoshiyuki Fukuyama (PACIFIC INDUSTRIAL CO..LTD.)

To understand the residual stress generation process in press-formed parts made of ultra-high strength steel, coupled FE analysis of shearing and forming using solid elements was conducted. The predicted residual stress at the edge after shearing and subsequent forming was generally consistent with the trends observed in actual measurements, indicating that this approach can be an effective tool for evaluating the influence of various factors during processing.

Development of Joining Technology to Improve the Crash Performance of Automotive Parts Using High Strength Steel Sheets

Tohru Okada･Takumi Mizutani･Hiroshi Horikawa･Taiga Taniguchi･Junichiro Suzuki･Hiroki Fujimoto･Hiroshi Yoshida (Nippon Steel Corporation)

To reduce the weight of automobile body, it is necessary to utilize the full potential of high strength steel sheets, and to achieve this, measures to prevent fractures in spot welds are key technology. In this paper, we report on various joining technologies to improve the crash performance of A-pillar made of 2.0 GPa-class hot stamped steel sheets.

Strength Prediction Model for Friction Stir Spot Welding of Aluminum Alloys - Part I -

Toshiaki Fukuhara (Mazda)･Yukihiro Sugimoto (Hiroshima University)･Mitsugi Fukahori･Kojiro Tanaka･Satoko Shimada･Itsuki Fujita (Mazda)

We focus on friction stir spot welding (FSSW) as a critical technique for joining aluminum alloys and aim to establish a methodology for predicting joint strength. The strength of FSSW joints is closely correlated with the cross-sectional geometry of the joint, which varies according to welding conditions; however, quantifying this relationship has traditionally been challenging. In this study, we developed a strength prediction model by sequentially integrating flow analysis based on a particle method with a machine learning approach.

Development of BEV Battery Pack and Key Technologies Utilizing Advanced Steel Sheets (First Report)
-Development of the Key Technologies to Achieve High Performance, Process Reduction, and Space Savings-

Naoki Kimoto･Yumi Saito･Yuuki Kitahara･Junichiro Suzuki･Atsuo Koga･Kunihiko Tohshin･Fumio Shibao･Taiga Taniguchi･Masahiro Kubo (Nippon Steel Corporation)

To address various challenges such as performance, weight reduction, high capacity efficiency, environmental compatibility, and cost-effectiveness required for BEV battery packs, a steel-based battery pack concept utilizing advanced steel sheets and related application technologies. The key technologies include eliminating electrodeposition coating and improving space efficiency, and performance evaluation methods to enable further advancements is also evaluated.

Development of BEV Battery Pack and Key Technologies Utilizing Advanced Steel Sheets (Second Report)
-Development of Lower Case Solutions for Eliminating Electrodeposition Coating-

Taiga Taniguchi･Naoki Kimoto･Atsuo Koga･Kunihiko Tohshin･Hiroshi Yoshida (Nippon Steel Corporation)

To achieve cost reduction and CO₂ emission cuts, we developed a battery box using high-corrosion-resistant coated steel without electrodeposition coating. Spot welding achieved an appropriate current range but led to corrosion degradation and liquid metal embrittlement due to excessive surface heating. To address these issues, we attempted to control current density at the steel surface.

Development of Solution Technologies Contributing to Higher Functionality in Automotive Chassis

Ryo Urushibata･Yuki Kitahara･Yoshinari Ishida･Ryo Tabata･Masahiro Matsuba･Kenichiro Ohtsuka･Tasuku Zeniya (NIPPON STEEL)

Solution technologies contributing to higher functionality in automobile chassis parts are introduced. The synergistic effect of advantaged steel sheets and solution technology gives part weight, cost, and LCA an advantage. As an example, a development case in front lower arm is presented.

Proposal of a Data-Driven Weakly Supervised Learning Method for Operation Mode Classification of Fuel Cell Garbage Trucks

Yida Bao･Xiang Zhang･Yiyuan Fang･Wei-Hsiang Yang･Yushi Kamiya (Waseda University)

This study proposes a versatile weakly supervised deep learning framework for operating mode classification, which enables statistical feature analysis of Fuel Cell (FC) refuse trucks. By fusing unsupervised clustering of CAN signals with expert knowledge, the method automatically generates large-scale training data, eliminating the need for expensive manual annotation. The proposed model achieves high classification accuracy while reducing annotation costs by over 75%. This framework enables efficient analysis for massive real-world driving data, establishing a foundational technology that has an ability to contribute to the broader design and control strategies of next-generation commercial vehicles.

The Structure of Anticipatory Mechanisms in Autonomous Vehicles

Masao Ito (NIL)

Previous research on autonomous vehicles and ethics has revealed that "anticipation mechanisms" (AM) are important for safety. They also have the potential to reduce the burden of scenario-based testing. This paper presents the results of an investigation into patterns for incorporating AM into autonomous vehicles.

Toward Generalizable Graph Learning for 3D Engineering AI
-Explainable Workflows for CAE Mode Shape Classification and CFD Field Prediction-

Tong Duy Son･Kohta Sugiura･Marc Brughmans･Andrey Hense･Zhihao Liu･Amirthalakshmi Veeraraghavan･Ajinkya Bhave･Jay Masters･Paolo Di Carlo･Theo Geluk (Siemens Digital Industries Software)

PhysicsAI delivers fast physics predictions enabling engineering teams to generate design variations rapidly. PhysicsAI learns physics behavior using Graph Neural Networks (GNNs) trained on mesh geometries and CAD models data. Engineers can explore various design variations, optimize parameters, and accelerate innovation. We present two applications: (1) External aerodynamic drag prediction using CFD simulation data, achieving high accuracy while reducing computation time from hours to minutes; (2) Vibration mode shape recognition and classification for NVH optimization, demonstrating expert-level accuracy on complex automotive structures. Validation from comprehensive automotive datasets will be presented.

Considerations Regarding the Safety Assurance of AI-Based Automated Driving Systems

Olaf Op Den Camp･Jan-Pieter Paardekooper (TNO)

In the development of Automated Driving Systems manufacturers and AV-developers make more and more use of AI-based systems. In some cases, even an end-to-end (E2E) AI approach is followed in which no longer a distinction is made between perception, path planning and actuation in the ADS of the vehicle. The paper presents considerations regarding the safety assurance of AI-based systems. The vulnerabilities of AI-based systems and the negative impact of these vulnerabilities on safety assurance will be discussed. It will be shown how the design of AI-based systems can be improved to allow for proper safety assurance.

On the Usefulness of a Magnetic Dipole Model for Calculating Leakage Magnetic Fields in Dynamic Wireless Power Transfer

Takehiro Imura (Tokyo University of Science)

In this paper, we validate the magnetic dipole model for evaluating leakage magnetic fields in dynamic wireless power transfer systems. After identifying the wireless power transfer region with respect to the boundary between the near and far fields, we clarify the range of applicability of the magnetic dipole model from the viewpoint of wavelength by comparing it with electromagnetic field analysis results, thereby demonstrating that analysis based on the magnetic dipole model is an effective and simple evaluation method.

Electrified Roads at the 2025 Osaka-Kansai World Expo Utilizing Cement Composite Materials
-Application of High-Performance Fiber Reinforced Cementitious Composite for EV Infrastructure-

Koichi Tanaka･Kazunari Sasaki･Asako Mizobuchi･Yasuhiro Tomita (OBAYASHI CORPORATION)

An experiment on dynamic wireless power transfer was conducted using EV buses at the 2025 Osaka-Kansai Expo. The transmission coil was embedded in precast concrete to protect the coil against bus wheel loads. This paper describes the development of the materials for the precast concrete and the concepts of the precast concrete design.

Demonstration test of power supply control for electrified roads at the Osaka-Kansai Expo

Yoshinori Tsuruda (DAIHEN)

At the 2025 Osaka-Kansai Expo, a demonstration test of in-motion power supply was conducted using an EV bus. Using the bus stop and part of the straight track of the venue's circular bus, power was supplied to the EV bus while it was stopped and in motion. This session explains the power supply mechanism and how power is continuously transmitted from multiple coils to the EV.

Optimal Location of Dynamic Wireless Power Transfer in the National Expressway Network

Yudai Honma･Hiroyuki Hasada･Junya Maruyama･Kazuma Kawai (The University of Tokyo)

This presentation examines the optimal location of DWPT in the national expressway network.

Technical Challenges and Practical Development for Social Implementation of In-Motion Wireless Power Transfer

Katsuhiro Hata･Eiji Hirota (Shibaura Institute of Technology)

In-motion wireless charging technology is expected to have technical challenges that do not exist in stationary wireless charging. While the details are wide-ranging, this presentation will focus on the technical challenges when looking toward social implementation, and introduce research and development aimed at resolving these challenges and their practical applications.

Standardization and Regulation and System of WPT for e-mobility

Yukio Yokoi (Takushoku University)

Standaradization and Regulations and System for WPT of e-mobility(EV) should be mainly considered on wireless energy transfer via air-gap. Related organizations such as Radio Act in Japan, International organizations of ISO/IEC for IS, ITU of frequency management and CISPR on unnessesary radiation and others should be considered. This report pointed out current tasks and expected direction for Static and Dynamic WPT.

Practical Development of Wireless Power Transfer Inverters

Haruki Aimi･Yoshio Tanai･Tatsuo Kataoka･Tsutomu Ishima (SPC ELECTRONICS)

This reports on the development status of technologies for compliance with SAE (Society of Automotive Engineers) standards toward the practical implementation of wireless power transfer systems, the reduction of leakage magnetic fields from coils, and related technical challenges.

Basic Study on Waveguide Power Transfer for Mobility Applications

Yuichi Masuda (2DC, Inc.)･Katsuhiro Hata (Shibaura Institute of Technology)

Waveguide Power Transfer propagates electromagnetic waves through a waveguide sheet installed along a route. A proximate receiver extracts power contactlessly, achieving continuous power supply with high positional freedom.

Trend in International Discussion on Safety Regulation for Automated Driving System, etc.

Toru Shimano (MLIT)

Automated Driving is expected as one of the key solutions to various social issues such as reducing traffic accidents and sustaining local transportation. This presenatation provides a brief overview of recent trends of international discussion regarding safety regulation for Automated Driving System, etc.

Study on Reducing Communication Disruptions for Achieving High-Reliability Communication During Automobile Operation
-Implementation of a Handover Control xApp Using OpenAirInterface and Evaluation in a Digital Twin Environment-

Haruki Osaki (Kozo Keikaku Engineering)･Akira Ito (Toyota Motor)･Masaya Sakamoto･Tetsuya Iye･Shinichiro Kataoka (Kozo Keikaku Engineering)

The realization of an advanced mobility society requires stable communication even in mobile environments. This study implemented a control xApp based on O-RAN Near-RT RIC to suppress communication interruptions during handovers on the OpenAirInterface. Furthermore, by constructing a wireless digital twin environment to replicate blockage during driving, we evaluated the impact of the proposed control method on interruption duration. This paper reports our latest results.

Reducing Workload in Remote Bus Operation Environments through Field-of-View Design

Naoki Furugohri･Yusaku Matsumura･Toshiyuki Sugimachi･Toshiaki Sakurai (Tokyo City University)･Syuichi Yahagi･Masaaki Onuki (The University of Tokyo)･Kimihiko Nakano (Takushoku University)･Jongseong Gwak

Remote operation is considered as a backup when automated buses go beyond their Operational Design Domain. Since buses use many mirrors, remote operators may experience increased workload due to multi-directional monitoring. This study proposes a remote-driving environment with a display layout based on the effective visual field to reduce workload and evaluate its effectiveness using a driving simulator.

The Application of Encrypted Control Technology to CACC

Takaharu Yamada (dSPACE Japan)･Kiminao Kogiso (The University of Electro-Communications)

CACC, known as the Cooperative Adaptive Cruise Control system, is a technology that maintains a constant distance between vehicles during driving by wirelessly transmitting information such as the speed and accelerator position of the preceding vehicle to the following vehicle. However, it is necessary to operate the communication channels and control parameters securely. In this study, we focused on Encrypted Control technology that enables operation with encrypted communication channels and control parameters, and attempted to apply it to CACC.

A Port Operation Use Case from the EU project MODI involving SAE Level 4 Automated Driving

Antoine Schmeitz･Sven Jansen･Masamichi Kiyoyanagi (TNO)

One key development of the EU MODI project concerns standardisation of an interface to control automated vehicles in the logistic system. The interface is validated in a use cases executed in The Netherlands. In this use case an unmanned automated truck is sent around a port terminal for picking up/dropping off a container. Because the truck is unmanned, it also requires the interactions with the logistics systems to be automated. In this paper the use case and system architecture will be explained and results of use case demonstration in the port of Rotterdam will be shown.

Recycled Glass Fiber from Waste Solar Panel Cover Glass

Yosuke Nukui (NITTO BOSEKI CO., LTD.)

In recent years, there is a strong demand for the materials used in automotive to reduce the environmental impact (CFP reduction, recycling), and glass fiber used in fiber-reinforced plastic is also required to contribute to this demand. In this research, we report the recycled glass fiber using waste solar panel glass, which is expected to be disposed of in large quantities domestically in the future.

Analysis of End-of-Life Vehicle(ELV) Seatbelt Webbing For Closed-Loop Recycling
-Second Report Quantification of Contamination and Degradation Reflecting Usage Environment-

Taiki Shiga･Masatoshi Kobayashi･Takeru Fukuda (Honda R&D)

In the first report of this study, we demonstrated that recycling ELV PCR into recycled materials using methods tailored to quality ensures stable recycled material quality. In the second report, we analyzed the soiling and degradation of PCR seatbelts used for approximately 15 years, classified the affected areas based on usage time, operating temperature, and solar radiation, and identified foreign substances causing quality deterioration.

Battery Recycling technologies and End-of-Life material recovery for the UK Battery Supply Chain

Hadi Moztarzadeh･Aditya Thirunavukkarasu･Julian Hetherington (Advanced Propulsion Centre UK)

The rapid scale-up of electric vehicle (EV) production is driving unprecedented demand for cathode active materials (CAM). This paper analyses how battery recycling technologies can support Europe's CAM supply by modelling end-of-life (EoL) battery recovery to 2040. A bottom-up model simulates EoL flows based on EV sales, pack lifetimes and chemistry shifts. The study also considers black mass availability from other sources like Battery Energy Storage System (BESS). Emerging recycling technologies are benchmarked to estimate secondary outputs of critical materials. Results show that high-efficiency hydrometallurgical process could supply a meaningful share of Europe's CAM precursor demand by mid to late-2030s, highlighting key technology gaps and the need for scaling recycling capacity to meet the requirements from emerging regulatory frameworks.

Development of SiOx Hard Coatings on Injection-Molded Transparent Polymers using Plasma CVD

Kazuhiro Fukada (Shibaura Machine)

A crack-free, high-hardness SiOx hard coating was fabricated on polycarbonate substrates using plasma chemical vapor deposition (CVD). A laminated structure composed of a silicone resin adhesion layer and a silica surface layer provided both excellent adhesion and optical transparency. However, delamination occurred under hot-water immersion. To address this, interfacial stability was analyzed using the Hamaker constant derived from Lifshitz theory. Introducing a Nb₂O₅ interlayer improved the thermodynamic stability of the interface, preventing delamination even after 250 hours in 60°C water. This approach enables rational design of durable coatings for automotive applications.

Development of Evaporation and Drying Modeling Techniques for High-Performance Coating Materials

Yuki Nakanishi･Masaya Minato･Ken Sakamoto･Tsutomu Shigenaga (Mazda)･Nozomu Hatakeyama･Ryuji Miura (Tohoku University)

Polymer–inorganic composite thermal management materials typically exhibit high filler loading, and the solvent dynamics during the coating's drying phase exert a critical influence on both desired performance and long-term durability. In this study, we developed a predictive model capable of accurately simulating solvent behavior within the film throughout the drying process, thereby enabling the efficient identification of material formulations and processing methodologies that satisfy targeted performance criteria. This report details the model architecture and presents representative application cases.

Development of Internal Structure Analysis Technology for Controlling Millimeter-Wave Transmissivity in Coating Films

Hiroto Matsui (Mazda)

We are advancing the development of high-performance bumper material technology that can achieve both electromagnetic wave permeability and design aesthetics at a high level. As part of this effort, we have established an automated analysis technology for the micro-scale three-dimensional filler structure within the coating film. This technology aims to elucidate the factors influencing electromagnetic wave permeability in bumper coatings and to efficiently determine the material and process conditions that meet the target performance.

Functional Extention of an integrated FC System Simulator "FC-DynaMo" by Vehicle and Battery Model and Controllers

Tomoaki Takagi･Toshikazu Ota･Kensuke Tsukahara･Yuji Yajima (MCOR Inc.)･Shigeki Hasegawa (Kyoto University)･Sanghong Kim (Tokyo University of Agriculture and Technology)･Miho Kageyama･Motoaki Kawase (Kyoto University)

FC-DynaMo, an integrated simulator developed for multiple applications of fuel cell (FC) systems, provides an integrated platform which consists of detailed component models and control functions for system-level analysis. In this study, the simulator was extended by the models which reproduce the dynamic behaviors of vehicle, Li-ion battery, and power-split controllers to track target vehicle speed. These extended functions were designed using publicly available information of 2nd-generation MIRAI (MIRAI-2) and it was validated that the developed simulator reproduced published vehicle performance, such as fuel economy and target speed tracking of MIRAI-2.

Proposal of Pedestrian Touch Vehicle Manipulation Control without Force Sensor for Low-Speed Unmanned In-Wheel Motor EV

Hongyuan Xing･Daisuke Gunji･Binh-Minh Nguyen･Osamu Shimizu･Hiroshi Fujimoto (The University of Tokyo)

In environments where pedestrians and low-speed unmanned EVs operate cooperatively in close proximity—such as during vehicle summons in parking lots—precise position adjustments are frequently required. However, such situations are unavailable to handle using only conventional external sensors or remote operation. This study proposes a control method for an in-wheel-motor EV that enables intuitive vehicle manipulation through light physical contact, without using external or force sensors.

Development of a Thermal Management System for a New BEV

Yugo Motegi･Yuuya Kogure･Ryousuke Satou･Masayoshi Tajiri (Nissan Motor Co.,)

A thermal management system based on the concept of "utilizing heat without waste" was developed for a new BEV. This system utilizes the waste heat from the electric powertrain and batteries, and adopts a water circuit with multi-way valves to achieve efficient heat transfer for thermal energy utilization, including air conditioning. Additionally, by integrating with the navigation system for battery temperature optimization, it contributed to improved energy efficiency.

The Evolution of Power Unit Development Process through MBD (Tenth Report)
-Deployment of 1D System Model to Performance Verification Phase-

Kenichiro Ogata･Kentaro Yamanaka･Tomoaki Sasagawa･Tsuyoshi Maeda･Motoki Takahata･Kei Sakamoto･Go Toshizane･Keiji Shiota (Honda Motor)

To achieve resilient product development and to improve development efficiency of power unit development process, applying MBD throughout entire development is required. This study outlines a framework for applying standardized models from performance design phase to verification phase. Specifically, this study shows the standardized 1D system model application for verification facilities that included the power unit transient bench for verifying power unit performance, and the driving simulator for verifying the overall performance of the vehicle.

The Evolution of Power Unit Development Process through MBD (Eleventh Report)
-Improvement of Development Efficiency by Standardizing Power Unit Transient Bench-

Kentaro Yamanaka･Tsuyoshi Maeda･Motoki Takahata･Tomoaki Sasagawa･Kenichro Ogata (Honda Motor)

To improve development efficiency of power units, the utilization of Model-Based Development (MBD) throughout the entire development process are promoted. Calibration and performance verification are conducted under simulated vehicle driving conditions by leveraging a 1D system model and a Power unit Transient Bench (PTB). This study describes efforts to standardize the test environment aimed at further efficient utilization of PTB.

The Evolution of Power Unit Development Process through MBD (Twelfth Report)
-Drivability Performance Verification Using Power Unit Transient Bench-

Tomoaki Sasagawa･Tsuyoshi Maeda･Kentaro Yamanaka･Seiya Nakasako･Kenichiro Ogata (Honda Motor)･Junya Iino (Honda R&D Asia Pacific)

Honda is promoting Model-Based Development(MBD) throughout the development process to improve efficiency of hybrid power unit development. This study presents an evaluation methodology utilizing Powertrain Transient Bench (PTB) to assess drivability performance, which has traditionally been verified using prototype vehicles. The proposed framework ensures reproducibility and comprehensiveness under transient conditions.This approach enabled front-loading of development, reducing the number of prototype vehicles and shortening verification periods.

Evaluation Review of a Chassis Dynamometer System for xEV Testing (Fourth Report)
-Overview of JASO E018 Part-3 for the Purpose of Reproducing Actual Driving Conditions-

Noriaki Nakate (JATA)･Hisakazu Suzuki (NALTEC)･Isamu Inoue (Ono Sokki)･Tomonobu Furuta (Meidensha)･Yoku Hirose (HORIBA)

The JASO E018 standard specifies control requirements and performance evaluation methods for chassis dynamometers to enable on-bench reproduction of real-world fuel consumption, energy consumption, and exhaust emissions evaluations, as well as diverse driving conditions. Considering the power characteristics of xEVs (electrified vehicles), this standard newly specifies evaluation methods and metrics enabling high-precision evaluations for these vehicles. This report outlines the standard and details the key points determining its various requirements.

From REEV to Hyper-REEV Enhancing the Driving Pleasure of Electrified Sports Cars

Sens Marc (IAV)･Christoph Koehler･Takuya Maeda (IAV)･Alexander Fandakov･Michael Riess (IAV)

Battery-powered electric drives are shaping the future of passenger cars, but electrified sports cars face reservations due to a lack of emotion. This article presents a powertrain concept for super sports cars that combines electric drive with combustion engine emotions using a range extender. The Hyper-REEV mode synchronizes engine acoustics with acceleration, offering high emotion and high efficiency. The article analyzes requirements and solutions for Hyper-REEV components, including battery design, e-machines, power electronics, and generator. The combustion engine's role is decisive, showcasing high efficiency and dynamic performance. The final part covers the overall concept and control strategy linked to SDV.

Accelerated Reliability Assessment for Power Electronics: Optimizing Traditional Testing Methods for EV Applications

Gerard Ibars Escarre･Yasmine Himene･Javier A. Corea-Araujo･Agustin Bucciarelli (IDIADA Automotive Technology S.A.)･Abdelali El Aroudi (Universitat Rovira i Virgili)

This paper investigates how optimized accelerated testing methodologies can reduce validation timeframes for power electronics in electric vehicle development. Current OEM approaches utilizing Power-Thermal-Cycle-Endurance and High-Temperature-Operation-Endurance protocols require >6-month validation cycles, conflicting with 2-year EV production timelines. Laboratory data reveals limitations applying conventional power cycling to GaN-based OBCs and SiC DC-DC converters, where standard Coffin-Manson models show reduced applicability. Analysis of physics-of-failure approaches and mission profile-oriented strategies demonstrates potential timeframe reductions. Results indicate properly configured accelerated aging tests incorporating junction temperature swing control and realistic switching conditions maintain reliability assessment accuracy while significantly accelerating validation processes for modern automotive power electronics.

A Study on Electrical Efficiency Improvement and Heating Control via Induced Inefficiencies of an Electric Compressor for EV Energy Consumption Improvement

Woojun Hur (Hyundai Motor)

This study proposes an integrated strategy to improve the electrical efficiency of electric compressors in electric vehicles (EVs), focusing on improvements in both motor design and inverter control. Key optimizations were applied to stator and rotor parameters, along with advanced inverter control techniques such as MTPA, DPWM, and SiC MOSFET integration. Additionally, a novel loss-based heating control method was explored to support heat pump operation under cold ambient conditions. Experimental validation confirms the effectiveness of the proposed approach, demonstrating its potential for improving EV energy consumption and system-level thermal management.

Contributing to an Energy and Resource Saving Society through Dynamic Wireless Power Transfer for xEV(Second report)

Yuki Konno･Naoya Kato･Tetsuji Mitsuda･Keisuke Tani･Hayato Sumiya･Hiroko Yahata･Koji Yamaguchi (DENSO)

In order to contribute to carbon neutrality, we aim to reduce the battery capacity to 1/3 or less as a means of reducing carbon emissions when manufacturing battery of electric vehicles. At the FY25 JSAE, we announced the specifications of the on-road power supply for a heavy-duty vehicle with 1/3 battery. In this case, we clarified the conditions under which long-distance continuous driving is possible by moving the subject to urban areas.

[Keynote Address] Status of Road Traffic Noise and Motor Vehicle Noise Regulation

Keisuke Yamamoto (Ministry of the Environment)

In this article, I would introduce the latest status of Road Traffic Noise. In addition, with regard to Motor Vehicle Noise Regulation, I would explain the history, the system and the status of addressing the issues to be addressed in the Future which was reported by "Future Policy for Motor Vehicle Noise Reduction (Fourth Report)" of Central Environmental Council.

Countermeasures for Pass-by Noise Limit in R51-03 Phase3

Koji Kato･Yoshitaka Atsumi･Hidenori Morita･Masashi Komada (Toyota Motor)

UN Regulation No.51-03 was introduced from 2024 as phase3.The countermeasures for phase3 which is the most strict noise limit are explained.

Trends in Road Traffic Noise Criteria in European Countries

Kazunori Harada (The University of Tokyo)･Naoya Maruyama (Kumamoto University)･Yasuhiro Hiraguri (Kindai University)･Takuya Oshima (Niigata University)･Shinichi Sakamoto (The University of Tokyo)

To contribute to discussions on Japanese Environmental Quality Standards for noise, this study investigates trends in road traffic noise criteria in EU countries. Assessment indicators, legal binding force, and consistency with WHO guidelines were analyzed. The survey revealed that many countries apply different criteria for new versus existing roads. This presentation introduces the current status in Europe and discusses its implications for future standards in Japan.

Reduction of Tire Radiated Noise by Pattern Design Considering Tread Deformation during Rolling

Hiroshi Fujii (THE YOKOHAMA RUBBER CO.,LTD.)･Fumihiko Kosaka (Dassault Systemes K.K.)

Band-pass filtering was applied to time-series data of tire coordinates in rolling simulations, revealing standing wave-like deformation in the tread ribs. Based on the interval of this deformation, lug groove arrangement was optimized to reduce radiated noise. This paper reports on the verification of these effects using simulation, as well as the results of confirmation through physical testing.

Evaluation Method of Annoyance due to Low-Frequency Noise from Large Vehicles

Makoto Morinaga (Daido University)･Shigenori Yokoshima (Kanagawa Environment Research Center / Kanagawa University)･Keiichiro Iwanaga･Tetsuya Doi (Kobayasi Institute of Physical Research)･Akiko Sugahara (Kindai University)

To examine the effect of low-frequency sound generated by heavy vehicles on annoyance, a laboratory experiment using a paired comparison method was conducted. The results suggested that even when A-weighted sound pressure levels were equal, sounds containing more low-frequency components were perceived as more annoying. However, when loudness levels were equalized, the difference in annoyance between the presence and absence of low-frequency sound decreased.

Virtualization as a Catalyst for Requirement-Based DevOps in Electrified Powertrain Systems

Dragana Borjan･Franz Eberhard･Stefan Eder･Samuel Swamidass･Avinash Singh (AVL List)

Electrified powertrain development faces rising software complexity, agile practices, and strict safety standards like ASIL-D. Traditional testing with physical prototypes struggles due to late hardware availability and high costs, driving a shift-left strategy for faster time-to-market. AVL applies a requirement-based approach using CI/CD/CT pipelines from specification to validation, integrating model-based sources and dynamic test environments. Virtualization with SiL and FMUs enables continuous integration of vECUs and plant models, improving transparency, reducing prototype dependency, and ensuring compliance. This framework supports early validation of complex E/E architectures and paves the way for AI-driven automation, such as MAESTRA AI for test case generation.

Application of Indicated Mean Effective Pressure Calculation Method Focusing on Specific Low-Frequency Components within Pressure Diagram to Double-peak Pressure Diagram

Keiichi Nagashima (Honda R&D)･Kazuo Tuchiya (Meiji University)

It has been revealed that the indicated mean effective pressure can be calculated from the low-order frequency components in the pressure diagram. This method uses an analytically derived formula from the definition formula, so it can be applied to all positive displacement machines regardless of the shape of the cylinder pressure. In this paper, we conducted verification with actual machine data, including the two-peak cylinder pressure. It was confirmed that the method can be applied in this case as well.

A New Measurement Method of Piston Friction Force

Takanori Suzuki･Yoshinori Nakayama･Atsushi Honda (SOKEN)･Motoharu Namiki･Masahiro Fujimoto (Toyota Motor)･Yukio Toda (Toda Racing)

A new floating liner measurement equipment was developed. With the equipment, piston friction force under actual engine operating conditions can be evaluated across a wide range of engine speeds. The key features of the equipment are follows; 1) implementation of a support of both-side of liner; 2) introduction of a new vibration noise cancellation method. With these features, the equipment can measure of the piston friction force with high repeatability (FMEP 3σ < 0.5 kPa) up to 4000 r/min.

Development of New Generation Hybrid Transaxle for Mid-size SUV

Hirokazu Arai･Shinichiro Suenaga･Kouhei Shimayabu･Junichiro Yasui･Yuji Yamaya･Keisuke Yuki･Hiroki Kato (Toyota Motor)

To achieve carbon neutral, we have developed a PHEV system for the new RAV4 as an electric vehicle option tailored to energy conditions and customer needs. By reconsidering the arrangement of high-voltage components, the system has been significantly downsized and lightened. In particular, this introduction focuses on the technologies behind the major improvements in the transaxle, including its miniaturization, weight reduction, and loss reduction.

Development of High-Performance e-Axle Oil

Kazunori Ishigami･Gou Katou･Makoto Maeda (JATCO. ltd)･Ryo Sasaki･Hitoshi Komatsubara (ENEOS Corporation)

The evolution of electric vehicles toward longer range and improved performance necessitates compact, high‑power, highly efficient e‑axles. Improving motor and gear performance, in turn, requires e‑axle lubricants that offer excellent heat dissipation and high lubricity. In this study, we developed an industry‑leading low‑viscosity oil that satisfies these requirements.

Consideration on Lubrication of High-Speed Rotating Gear (Fourth Report)
-A Parametric Study Employing a Lubrication Device-

Kazuki Sakai･Masayoshi Ohno･Junji Yamada･Tomoyuki Hara･Naohiro Fujita･Tetsuya Sato･Kensuke Suzuki (UNIVANCE)

Based on our previous findings, we have developed an efficient lubrication system that utilizes the suction airflow generated at the end of meshing in high-speed rotating gears, and have reported its effectiveness. In this study, as part of an adaptability assessment aimed at future mass production, we conducted a parametric study to examine the design conditions of the lubrication device. This presentation introduces a portion of those results.

Influence of Lubrication Direction on Cooling Performance in High-Speed Traction Drives and Observation of Oil Film Behavior

Shunki Boku･Yuki Kawamoto･Shunichi Tajima･Masayuki Ochiai (Tokai University)

Traction drives at high peripheral speeds are attracting attention as reduction mechanisms for electric vehicles, but thermal cooling under high-speed operation remains a major issue. This study measured roller surface temperatures under different lubrication directions and confirmed that 'disengagement lubrication' provides superior cooling performance. Additionally, oil film flow was visualized to qualitatively investigate the mechanisms behind enhanced cooling in the 'disengagement lubrication' and to support a foundational understanding of the observed thermal behavior.

Method of Simultaneous Multi-Point Instantaneous Contact Pressure and Temperature Measurement on Gear Tooth Surfaces Using by Thin-film Sensors

Yuji Mihara (Tokyo City University)･Michiyasu Owashi･Takumi Iwata (MOTORA)

Understanding the direct contact load and temperature distribution of gear units, which are essential for power transmission in drivetrains, is crucial. Therefore, we introduce application examples of thin-film sensors and previous measurement cases that enable these measurements using thin-film sensors.

Reducing Life Cycle CO₂ Emissions and Battery Cost in BEVs through Bearing Friction Loss Minimization

Seiya Nishizawa (Schaeffler Japan)･Franz Voelkel (Schaeffler Technologies AG & Co. KG)･Ken Sakaguchi (Schaeffler Japan)･Volkhard Walther･Johannes Kerstiens (Schaeffler Technologies AG & Co. KG)

Bearing losses add up to a significant share of overall vehicle power losses. On the one side, this influences the downstream emissions, on the other side a BEV's upstream emissions are heavily affected well as a certain capacity of the battery is only needed to feed these losses. Every piece of energy which is not lost to friction doesn't have to be stored in a battery. This lecture discloses the hidden potentials in mechanical power loss reduction, especially for bearings, by means of power density increase, on-the-point optimization and drag loss minimization.

Improving Winter Driving Range of EVs with a Desiccant Device: Ceramic Humidity Regulator (CHR)

Hirotaka Saito･Yukio Ihara･Hajime Ota･Naoki Sakai (NGK Corporation)

One major challenge for electric vehicles (EVs) in winter is reduced driving range due to heating demands. Heat loss from ventilation for window defogging is a key factor. To address this, we developed the Ceramic Humidity Regulator (CHR), a desiccant device combining a moisture-adsorbent material with a ceramic PTC heater. This integrated system controls humidity while providing efficient heating. Vehicle tests showed that, compared to conventional automatic air-conditioning, CHR reduced heating power consumption by about 25%. This improvement is expected to enhance EV driving range under cold-weather conditions.

Holistic Evaluation of Electric Vehicle Efficiency: Benchmark Study of R-474A, R-1234yf, and R-744 Using Digital Twin Simulation

Christian Macri･Alvaro De Leon･Felix Flohr (Daikin Chemical Europe)

The transition to battery electric vehicles (BEVs) comes with several challenges such as energy efficiency and the resulting driving range. The thermal management systems play a pivotal role ensuring optimal energy efficiency and passenger comfort. Refrigerants play a crucial role, as their properties impact heat exchange efficiency and overall energy consumption. This study presents a comprehensive benchmarking of the new refrigerant R-474A against R-1234yf and R-744 in a BEV thermal management system. A simulation has been conducted, beginning at system level, progressing to vehicle level, and concluding with evaluations under transient driving conditions across various driving patterns and temperature profiles.

Experimental Study and Simulation on the Performance of a Heat Pump System with Novel Low-GWP R474A for New Energy Vehicles

Binbin Yu･Yunlong Zhang (Shanghai Jiao Tong University)･Hao Nie･Yasutaka Negishi･Shohei Ajloka･Asuka Bunno･Kei Yamamoto (Daikin Industries)

This study investigates the cycle performance and system behavior of a novel refrigerant, R474A in the heat pump for new energy vehicles. Results show under both cooling and heating conditions, R474A demonstrated strong performance: a COP up to 3.67 under light-load conditions, a maximum cooling capacity of 7004.5 W, and a maximum heating capacity of 6044.5 W. Comparative analysis revealed that R474A outperforms R134a and R290 in terms of cooling and heating capacity across conventional and extreme operating conditions, while maintaining a higher COP than R290. Notably, R474A overcame the operational limitations of R134a at extreme low temperatures and exhibited minimal temperature non-uniformity from glide effects, ensuring satisfactory thermal comfort. These findings highlight R474A's significant potential as a sustainable alternative refrigerant for NEV heat pump applications.

Testing of Novel Refrigerants in an Indirect Automotive Heat Pump Module
-DroP in comparison of R-1234yf, R-474B, R-491A, and R-290-

Tomas Mrkvica･Jan Tuhovcak･Milos Fojtlin (SATTELO)

Driven by electric mobility and mobile machinery needs, the market demands efficient thermal management with refrigerants that work across climates, meet low-GWP and PFAS-free requirements, and require minimal system changes. This study evaluates two novel blends, R474B and R491A, as drop-in candidates versus common automotive refrigerants. Laboratory tests under heating, cooling, and high-load conditions show performance can be limited by existing equipment and safety constraints, though cooling and dehumidification needs were met. Overall, the results show the new refrigerants are technically viable and offer a promising path for future EV thermal management.

Development of a System Simulation Model for Estimating Short-Circuit Discharge Energy of an Automotive Electric Compressor

Kengo Nagai･Ryoto Nakayama･Itsuki Masuda (Nagoya University)･Yasutaka Negishi･Asuka Bunno･Takashi Usui (Daikin Industries, LTD.)･Koichi Shigematsu･Jun Imaoka･Masayoshi Yamamoto (Nagoya University)

In recent years, hydrofluoroolefin (HFO) refrigerants have gained attention for their high cooling performance and low global warming potential (GWP). However, if a short-circuit discharge occurs inside an in-vehicle electric compressor and the refrigerant absorbs the discharge energy, it may undergo combustion or thermal decomposition. To assess this risk, short-circuit tests were performed on an actual compressor to measure discharge waveforms and energy. Using circuit parameters obtained from these tests and from compressor teardown analysis, a system simulation model was developed to estimate discharge energy, incorporating overcurrent protection and output-control functions.

Investigation of Airflow Characteristics in Simplified Vehicle Cabin During Fresh Air Rate Control Using Stereo PIV Visualization

Kosuke Onishi･Takuji Nakashima･Kazuki Ito･Hidemi Mutsuda (Hiroshima University)

Reducing air‑conditioning energy consumption is critical for electric vehicles. With the advent of autonomous driving, the vehicle cabin is increasingly envisioned as a living space, making occupant comfort as important as energy efficiency. In this study, a simplified vehicle cabin model was used to investigate an intermediate AC mode that mixes fresh and recirculated air. The influence of this mode on the cabin airflow field was examined experimentally through stereo PIV visualization. Flow‑field control strategies were evaluated with the aim of improving thermal comfort while minimizing AC energy use.

Investigation of Vehicle Cabin Airflow Characteristics for Pre-Conditioning Efficiency Enhancement Using CFD and Proper Orthogonal Decomposition

Kazuki Ito･Hikaru Nishikokura･Takuji Nakashima･Kosuke Onishi･Hidemi Mutsuda (Hiroshima University)

In the vehicle cabin, the airflow from the HVAC system forms a complex flow field due to interactions such as impingement on interior components and the characteristics of the air-delivery configuration. In this study, CFD simulations of the vehicle cabin flow field were conducted under multiple conditions by varying the outlet direction and ventilation mode to achieve efficient cabin ventilation. Furthermore, Proper Orthogonal Decomposition (POD) was applied to extract characteristic flow modes, from which effective control strategies for improving HVAC airflow efficiency were investigated.

Measurement and Analysis of Automotive Cabin Thermal Insulation Characteristics and Elucidation of Heat-Gain/Heat-Release Behavior

Ying Sun･Haruki Nakamae (Molten Corporation)･Shigeru Ogawa (Ogawa Fluid Research Institute)･Takahiro Tsutsumoto･Tsuyoshi Sugihara (Hiroshima Industrial Promotion Organization)

Improvement of the driving range of electric vehicles (EVs) requires not only advances in battery systems but also the reduction of energy losses associated with cabin climate control. In the present study, heat-flux measurements and thermal analyses were performed using both an actual EV and a controlled experimental apparatus in order to obtain a detailed understanding of the thermal insulation characteristics of EV cabins. Particular attention was directed toward the heat-gain and heat-release behavior within multilayer cabin-wall structures. The internal temperature distribution and the influence of external airflow on heat transfer through the wall were examined, and the resulting findings are reported herein.

Development of a Personalized Thermo-regulation Model

Rikiya Okabe (Mazda)･Akira Togii (Hiroshima University)･Hideaki Nagano･Masanori Shukuya (Tokyo City University)

To enhance individual comfort in vehicle cabins, blower levels and outlet temperatures should be automatically adjusted for each occupant. This requires a human thermoregulation model and a climate control system based on that model. We developed a personalization method for the human thermoregulation model and demonstrate its application.

[Keynote Address] Analysis of Eigenmode Responses in Motorcycle Cornering Dynamics

Tetsuya Kimura (None)

This study investigates motorcycle behavior during the transition from straight running to cornering by decomposing the motion into individual eigenmode responses, thereby clarifying the contribution of each mode.

A Method for Non-visual Navigation of Motorcycle Riders Using In-Helmet Haptic Feedback

Taiki Tomoto･Tomoya Kitani･Takuro Sone (Shizuoka University)

Screen gazing associated with the widespread use of smartphone navigation on motorcycles is a significant factor increasing accident risk. In this study, a tactile presentation system was constructed by arranging vibration actuators inside a helmet, and an intuitive directional indication method is proposed. Perceptual characteristics were evaluated through subject experiments to investigate the potential of a novel navigation system independent of visual information.

A Method for Lean Angle Estimation of Motorcycle Riders via Factor-Graph-Based Integration of Onboard GNSS/IMU

Yuki Matsumura･Tomoya Kitani (Shizuoka University)

Estimating the rider lean angle, defined as the rider's inclination relative to the motorcycle body, is essential for elucidating posture control mechanisms during cornering and for quantitatively assessing riding skill. This study proposes a method to estimate rider lean angle by integrating time-series data obtained from on-board GNSS and IMU sensors using factor graph optimization.

Motion Measurement of a Motorcycle Using IMUs

Junji Hirasawa (Ibaraki KOSEN)

This paper discusses the motion measurement of a motorcycle using inertial measurement units (IMUs). The author proposes a novel method for estimating position from omnidirectional images for the purpose of motorcycle motion analysis. To verify the validity and accuracy of the proposed method, the analysis is performed using measurement results obtained simultaneously from multiple compact IMUs. The processing of the measurement data and the calculation of centrifugal force are also discussed.

Influence of Road Friction Characteristics on Two-Wheeled Vehicle Behaviors

Ichiro Kageyama･Atsushi Watanabe･Yukiyo Kuriyagawa･Tetsunori Haraguchi (Nihon University)･Tetsuya Kaneko (Oosaka Sangyo University)･Minoru Nishio (Absolute)

This study aims to understand the effects of various road friction characteristics on motorcycle motion. To achieve this, motorcycle tire characteristics that represent characteristics according to road friction characteristics are constructed using a brush model that represents adhesion and slippage regions. The constructed tire model is then incorporated into a quasi-steady analysis model for a motorcycle, and vehicle characteristics on roads with different road friction coefficients are analyzed.

Analysis of the Influences of Motorcycle Design Parameters on Weave Mode Stability

Tsuyoshii Katayama･Masanori Myoyo (Kurume Institute of Technology)･Yuto Fujimoto (Kurume Institute Technology)･Takahiko Yoshino (Kurume Institute of Technology)

Weave mode of motorcycles shows complex behavior depending on the vehicles design parameters. Interpretation is particularly difficult in eigenvalue analysis using multi-degree-of-freedom equations that include frame flexibility. In this paper, differences in the behavior of stability in weave mode are discussed using four types of design parameters that already been published. It is shown that the main factors are the flexibility of the frame, the cornering power of the tires, and the aerodynamic characteristics.

Consideration of Pitch Attitude of Personal Mobility Vehicles (PMVs) During Tilted Cornering

Tetsunori Haraguchi (Nagoya University / Nihon University)･Tetsuya Kaneko (Osaka Sangyo University)

During cornering in passenger cars, body roll slightly lowers the driver's forward gaze point, and a gently nose-down roll posture is generally considered desirable. In contrast, in PMVs, where the body tilts significantly inward, the driver tends to look “upward” toward the direction of travel. Based on these observations, this study provides a hypothetical consideration of the appropriate pitch attitude of a PMV during cornering and its relationship to the front and rear suspension characteristics.

Towards Establishing Methodology of Naturalistic Driving Simulator Experiment with Multi-agent Traffic Simulation

Jun Tajima (Misaki Design)･Keisuke Suzuki (Kagawa University)･Hironori Suzuki (Toyo University)･Sou Kitajima (JARI)

The realization of realistic virtual traffic environments through multi-agent traffic simulation has enabled the conduct of naturalistic simulator tests, which is antithetical to condition-controlled simulator experiments. Accordingly, this paper discusses the purpose and role of naturalistic simulator tests, their differences from conventional simulator tests, acceptable interventions or operations in experiments, available and effective methods of experimental data analysis.

Analysis of Differences in Driving Behavior between Two Countries in a Naturalistic Simulator Experiment

Keisuke Suzuki･Naoki Nishiyama (Kagawa University)･Kultida Payappanon･Sunhapos Chantranuwathana･Nuksit Noomwongs (Chulalongkorn University)･Yoshitaka Mimura (Honda R&D)

This paper discusses a methodology for analyzing differences in driving characteristics and risk-taking behavior between the two countries. Using a naturalistic simulator environment proposed by the authors, we analyzed motorcycle risk-taking behavior in Japan and Thailand. Furthermore, we used SEM to visualize the factors that cause behavioral differences and their relationship with human personality.

Verification of Speed Control Support Effectiveness for Electric Scooters Using the Metaverse

Makito Toki･Keisuke Suzuki (Kagawa University)･Shusaku Toda (Aioi Nissay Dowa Insurance)

To reduce traffic accidents involving electric kick scooters, we analyzed the speed reduction effect of information presentation in a metaverse environment replicating actual urban areas through a naturalistic experiment that replicates normal driving behavior. For this study, we developed a proprietary electric kick scooter simulator and conducted experiments with approximately 20 participants. The results revealed that traveling at 10 km/h significantly reduced collision risk regardless of the risk detection distance. Furthermore, we confirmed that auditory information presentation using beeps had the highest effect in suppressing speeding, while visual information presentation was associated with lower levels of annoyance.

The Effect of Camera Monitoring System Information Presentation on the Sense of Security of Automobile Drivers and Motorcycle Riders

Koki Miyamoto･Keisuke Suzuki (Kagawa University)･Takuya Izumiguchi･Seishi Takagi (Penstone)

We modeled the effects of information presentation via camera monitoring systems on the sense of security of four-wheeled vehicle drivers and two-wheeled vehicle riders using structural equation modeling. Regarding direct effects on the sense of security, we found that for four-wheeled vehicles, the degree of situational awareness significantly influenced this sense, while for two-wheeled vehicles, psychological stability and physical load exerted greater influence than the degree of situational awareness.

Towards Empathetic Interfaces: Effect of Sadness Expression Feedback on Headway Distance Maintenance Characteristics

Toshiaki Kimura (Kindai University)･Mariko Shirai (Shinshu University)･Keisuke Suzuki･Tetsuro Butsuen (Kagawa University)･Jun Tajima (Misaki Design)

Emotions are psychological mechanisms that automatically evoke behavior. Therefore, we are conducting research on empathetic interfaces to utilize emotions in promoting safe driving. This paper presents the results of foundational research that experimentally examined the effects of feedback of sad facial expressions to drivers on their headway distance maintenance characteristics. The experiments consist of two parts, preliminary investigation of questionnaire survey and main investigation using driving simulator.

Development of Pedestrian Model of Road Crossing Behavior based on Data obtained from Mixed-Reality Pedestrian Simulator Experiment

Keita Oda (Misaki Design)･Keisuke Suzuki (Kagawa University)･Toshiaki Kimura (Kyoto Tachibana University)･Hironori Suzuki (Toyo University)･Jun Tajima (Setouchi Simulator Inc.)

We observed pedestrian road crossing behavior using Mixed Reality pedestrian simulator, which displays integrated view of real images and computer graphics and allows the pedestrian subjects to walk safely. The simulator tests were conducted under multiple conditions, including the presence or absence of parked vehicles, street trees, and guardrails, as well as varying road width and traffic volumes. The behavior data is analyzed from the perspective of safety attitude. Using the data obtained, discrete choice based pedestrian model is developed to simulate the road crossing behavior of pedestrians, which will be utilized to increase the reality of multi-agent traffic simulation.

Accelerating Sophisticated Automated Driving System Development and Evaluation through Proactive Multi-Agent Traffic Simulation

Sou Kitajima･Shun Endo･Nobuyuki Uchida･Kunio Yamazaki (JARI)･Naoki Suganuma (Kanazawa University)･Tadashi Okuno (OS Planning)･Jun Tajima (Misaki Design)

This paper proposes a systematic evaluation methodology to accelerate the development of sophisticated Automated Driving Systems (ADS) by proactively utilizing multi-agent traffic simulation. Advanced ADSs are expected to continuously improve their collision avoidance capabilities and tactical driving performance within the operational design domain through frequent software updates. The proposed virtual testing platform enables comprehensive and iterative evaluation of integrated ADS performance under diverse and interactive traffic conditions. It supports developers in achieving reliable ADS behavior prior to real-world deployment by facilitating quantitative assessment of the system's ability to anticipate and mitigate potential safety risks and disruptions to surrounding traffic flow.

Analysis of Highway Merging Driving Behavior by Parameter Estimation of Discrete Choice based Driver Model using data from Networked Multi-Participant Driving Simulator

Tohru Yoshioka (Mazda)･Hironori Suzuki (Toyo University)･Jun Tajima (Misaki Design)

We model merging and mainline vehicle behavior on highways to support merging assistance. Using a driving simulator where ten drivers share the same virtual traffic environment, we examine interactions among vehicles and agent models under mixed traffic conditions. From merging actions involving vehicle‑to‑vehicle interactions, each driver's behavior is described within a unified modeling framework, enabling analysis of differences across vehicles.

Analysis of Individual Lane-Change Behavior and Interaction among Vehicles Caused by Lane Closure on Highway Using 10-Networked Driving Simulators

Hironori Suzuki (Toyo University)･Ryuya Seki (Gradute School of Toyo University)･Seiya Fujii･Hiroshi Unesaki･Shuichi Kondo･Toru Yoshioka (Mazda)

This paper deals with observation and analysis of lane-change behavior of individual drivers caused by lane closure on the highway, and simultaneously, investigates the effect of resulting interactions among vehicles on traffic flow. For this purpose, we conduct simulator experiments using networked driving simulator which can offer same virtual road traffic environment to maximum of 10 drivers.

Unified Path Planning Algorithm for Traffic Participants in Multi-Agent-based Simulation (Part2)

Ryuya Seki･Hironori Suzuki (Toyo University)･Jun Tajima (Misaki Design)

We are exploring possibility of discrete-choice-based path planning algorithm that can be uniformly applied to vehicles, motorcycles, pedestrians, bicycles, and other traffic participants appear in the multi-agent traffic simulation. As part 2 of the research report, we present the simulation result that indicates multiple agents can move narrow path interacting with each other in this paper. We also discuss how to integrate the required behavior to obey traffic rules such as stop at stopping location into our model.

Comparison of Pedestrian Behaviors Observed in Real-World Surveys and MR Pedestrian Simulator Experiments

Hironobu Hasegawa･Taiki Ago (Kagawa University)･Makoto Kasai (National Institute of Technology, Akita College)

Researchers typically understand pedestrian behavior in road environments using two main approaches: observation and experimentation. Observation enables the capture of actual behaviors but makes it difficult to obtain sufficient samples of rare events. Experimental approaches, in contrast, allow researchers to design specific scenarios, and mixed-reality (MR) simulators in particular enable the collection of pedestrian behavior under controlled conditions with embodied interaction. This study compares data obtained through these two approaches and discusses their implications for the development of pedestrian behavioral models.

Vibration Simulation of Structural Members Bolted with CFRP

Satoru Kuga･Yuuki Kawaharabashi･Yoshinao Kishimoto･Yukiyoshi Kobayashi･Yuki Ohno･Daiki Ariyama (Tokyo City University)

Carbon fiber reinforced plastic (CFRP) is expected to be applied to automotive structural frames, leveraging its excellent specific strength and specific stiffness, as well as its anisotropic properties. In this study, a finite element simulation method was developed to predict the natural vibration modes and natural frequencies of structural members bolted with CFRP. Its effectiveness was evaluated by comparing the simulation results with actual hammering test results.

Effect of Fiber Structure on the Strength of CFRTP Injection Molded Parts

Suzuho Sasamoto･Mutsuki Hamada･Souichiro Nishino (Ibaraki University)･Hidemaru Sootome･Kenta Iwasawa (Industrial Technology Innovation Center of Ibaraki Prefecture)

Lightweight, high-rigidity CFRTP is seeing expanding applications, yet its fiber structure changes depending on molding conditions, leading to strength inhomogeneity.This study reports on the influence of fiber structure on strength through strength evaluation, X-ray CT observation, and orientation analysis.

Foaming Prediction Technology for Automotive Polyurethane Using a Model-Based Approach

Jin Tomotsu･Junichiro Yamashita･Junji Katagihara (Daikyo Nishikawa)･Hideyuki Yukawa･Hiroki Tanizawa (Hiroshima University)･Minoru Inoue (Mazda)･Toshimi Nakaya (Hiroshima University)･Nozomu Hatakeyama･Ryuji Miura (Tohoku University)･Shinichi Kihara (Hiroshima University)

For polyurethane foaming phenomena, a foaming model integrating reaction properties and visualized data of foaming behavior was constructed to reproduce, through modeling, the formation of cellular structures such as cell diameter, throat diameter, and porosity. This method enables the prior derivation of bubble-control conditions feasible in actual molding, leading to the optimization of molding methods that directly affect acoustic, thermal, and surface quality.

Effectiveness Evaluation of Trajectory Planning at Highway Merging Sections Using Quantum-Inspired Optimization

Koji Oya･Ryuji Takahashi･Kota Matsuura･Kenshin Yamamoto (MIRISE Technologies)

At the JSAE 2025 Autumn Congress, we presented a trajectory planning using a quantum-inspired machine for combinatorial optimization. We conducted trajectory planning simulations based on actual traffic scenario and verified the effectiveness of the proposed method by comparing the simulation results with real-world data.

A Data-driven Algorithm Development Framework Leveraging an Interactive Multi-Simulator

Shohei Kobe･Akira Ito (Aichi Institute of Technology)･Ken Kinjo･Yuki Asada (DENSO)･Fumitake Tsuji･Kohichi Yoshioka･Kazunori Ban (Toyota Technical Development)

While data-driven algorithms enable flexible decision-making where rule-based approaches struggle, achieving the required functionality often requires large volume of training data. This study proposes a development framework that enables data-efficient acquisition of this functionality from a small amount of simulator-generated training data guided by functional requirements.

Road Adaptive Control with Haptic Steer-by-Wire

Yusuke Yamanaka･Hiroaki Kuwahara (Shibaura Institute of Technology)

This study develops a Steer-by-Wire system using bilateral control to precisely feed back road reaction forces to the driver. Furthermore, based on the acquired road information, the system suppresses unstable driving conditions. This approach aims to achieve both realistic steering feel and vehicle stability. The effectiveness of the proposed system was verified through simulations and experiments.

Design of an Autonomous Distributed Four-Wheel Independent Drive and Steering Control System Based on Broadcast Control

Akira Ito (Aichi Institute of Technology)･Shun-Ichi Azuma (Kyoto University)

This study addresses the problem of distributing driving force and steering angle for a vehicle equipped with corner modules capable of independent four-wheel drive and steering. As a new approach replacing conventional rule-based methods, we propose an autonomous distributed allocation rule using broadcast control based on multi-agent control theory.

Optimization and Development of a 48V Cooling Fan System with Direct Control Strategy Based on TMD Controller

Chanwoong Jo (Hyundai Motor)

This paper proposes a method to optimize and directly control 48V cooling fan motors in vehicle thermal energy systems, replacing traditional 12V systems. The 48V system reduces power loss and is suitable for high-power loads. Through design optimization, it achieved a 4% efficiency improvement, 300g weight reduction, and 10mm thickness reduction. The Field-Oriented Control (FOC) method was applied for flexible adaptation to various motor specifications. Twenty control parameters were identified, and their effectiveness was validated through testing. This research is planned to be applied to future Software Defined Vehicle (SDV) development.

Driving Risk Prediction Over a Repetitive Driving Pattern

Michele Guagnano (Politecnico di Torino)･Yecan Wang･Shigenobu Mitsuzawa (Honda Motor R&D)･Massimo Violante (Politecnico di Torino)･Riccardo Groppo (Sleep Advice Technologies)

Road traffic accidents remain a major global issue, yet professional drivers face a distinct and often underestimated risk: long-term exposure to repetitive routes. To address this, we conducted a longitudinal study with 54 participants over a 12-day protocol, performing 4 consecutive laps during each day on a simulator on a repetitive track to replicate routine shifts. The resulting dataset fuses driving, eye-tracking metrics, and physiological features. An ML model was trained to predict the risk level of a lap with data from the previous one. The model was validated with a K-Fold approach, by achieving a mean accuracy of 91%.

Advanced Signal Processing for Time Division MIMO Type Millimeter-Wave Radars

Yoshihisa Amano･Hideo Inoue (Kanagawa Institute of Technology)

In this paper, a new signal processing technique, which improves performance of Millimeter-wave radar, is proposed. Since 2017 radar chips with Time Division MIMO function are widely available, but this technology has a drawback of reduced dynamic range of velocity. So the recent trend is obviously moving to another technology, Doppler Division MIMO, but it also has a drawback of self-interference in the spectrum. Authors has replaced FFT with 2-3 dimensional Matching Pursuit algorithm, and has successfully enlarged dynamic range of velocity.

Millimeter Wave Reflection Characteristics and Modeling on Snow-Covered Road Surfaces

Hiroshi Kuroda･Yoshihisa Amano･Aiko Hibino･Masashi Mizukoshi･Hideo Inoue (Kanagawa Institute of Technology)･Kengo Sato (National Research Institute for Earth Science and Disaster Resilience)

For safety validations of automated driving vehicles, simulators in the cyber world are important. The DIVP project is developing a simulator to reflect real environment including snowy weather condition. Last year, reflections from snow surface regarding light and millimeter wave were reported at JSAE. Essentially, millimeter wave can penetrate snow to some extent. Considering real snow-covered road condition, characteristics of multiple reflections from snow and road surface material in millimeter wave are measured. Also, the mathematical model using S-function to calculate multiple reflections are created. Experiments were conducted while varying the thickness of the snow on road surface material. Measured results are well matched with the model.

Verification of Millimeter-Wave Radar Vital Sensing Simulation Method for In-Vehicle Child Presence Detection

Taiki Nakayama･Yasuhiro Tada･Yosuke Saiki･Kenshi Horihata (Kozo Keikaku Engineering)･Swagato Mukherjee･Greg J. Skidmore･Tarun Chawla (Remcom Inc.)

Millimeter-wave (mmWave) radar, capable of non-contact detection, is attracting attention as a method for Child Presence Detection (CPD) to address the social issue of children being left behind in vehicles. In this study, we analyze a breathing human body model by combining the Ray Tracing method and the Physical Optics to verify the simulation methodology for mmWave vital sensing.

Effect of Snowfall on Detection Characteristics of Automotive Millimeter Wave Radar

Kengo Sato･Kazuma Togashi (National Research Institute for Earth Science and Disaster Resilience)･Kouji Morikawa (Meteorological Research Institute for Technology)･Naoto Hagino･Hideo Inoue･Shigeo Kimura (Kanagawa Institute of Technology)

We propose an equation representing the reduction rate of received signals on in-vehicle millimetre-wave radars due to wet snow accumulation utilising publicly available meteorological data such as those from the Automated Meteorological Data Acquisition System. To derive this equation, we conducted signal reduction tests on millimetre-wave radars with varying the liquid water content(LWC) and thickness of snow specimen, alongside wind tunnel tests measuring snow accumulation growth on flat plates. The proposed equation is a function of the LWC and spatial density of the falling snow, as well as time.

Study on Improvement of Mixture Formation in Hydrogen Direct-Injection Engines Using Air Injection

Hiroki Sawaguchi･Hidenori Kosaka (Institute of Science Tokyo)

The promotion of mixing between hydrogen and air is effective for improvement of thermal efficiency of hydrogen direct injection engines. This study proposed an engine system with air direct-injection in order to improve mixing characteristics, and implemented zero-dimensional simulation to evaluate the thermal efficiency of proposed engine. Moreover, CFD analysis of hydrogen jets and air jets into a constant-volume container was conducted in order to investigate the effects of air injection to the mixture formation.

Effect of Increased Injection Rate on Thermal Efficiency and Output-Power under Supercharged Operation in Low-Pressure Direct-Injection Hydrogen Engines

Kentaro Minoda (Tokyo City University)･Nobuhiro Shimmura (Tokyo City University / Kawasaki Heavy Industries)･Masakuni Oikawa･Seiya Yamada･Shota Tsukamoto (Tokyo City University)･Sekai Miyamoto (Kawasaki Heavy Industries)･Yuji Mihara･Yasuo Takagi (Tokyo City University)

Supercharging is an effective method for increasing the output of low-pressure direct-injection hydrogen engines. However, there are concerns that it may increase NOx emissions owing to worsened mixture formation. In this study, the engine performance under high-output operation was evaluated using injectors with the same nozzle hole geometries but different injection rates. The results confirmed that employing a high-injection-rate injector improved thermal efficiency and reduced NOx generation during high-output operation.

Research on Abnormal Combustion in Hydrogen-Fueled Spark Ignition Engines (2nd Report)
-Construction of Pre-Ignition Prediction Model Caused by Hot Surface-

Hiroki Kambe (Toyota Industries Corporation)･Ryo Masuda (Toyota Central R&D Labs.)･Kohei Kuzuoka (AIST)

The first report revealed that NO in the residual gas of Hydrogen-fueled spark ignition engines significantly reduces ignition delay time. This report presents a 1D-CFD model for predicting pre-ignition due to thermal surface ignition, incorporating the effects of NO. In experiments, spark plug temperatures were measured to investigate the mechanism of pre-ignition. Using these experimental results, in-cylinder flow and thermal source temperature were modeled, leading to the construction of the pre-ignition prediction model. The model successfully reproduced the pre-ignition phenomena observed in actual engines when advancing the ignition timing.

Study on Homogeneous Mixture Formation by High-Flow Hydrogen Jet

Seiya Nishimura･Akichika Yamaguchi･Shingo Kitani (DENSO)･Hajime Kataoka (SOKEN)

Hydrogen engines are attracting attention as a pathway toward carbon neutrality; however, achieving abnormal combustion avoidance, high output, and low NOx emissions requires overcoming the challenge of homogeneous mixture formation. This study focuses on high-flow hydrogen jets for large engines and analyzes the formation mechanism using advanced visualization techniques. Based on the identified mechanism, injection and jet requirements effective for homogeneous mixture formation were derived through CFD analysis.

A Study on Waste Heat Recovery Efficiency using Thermoelectric Mdules in Hydrogen Engines

Itsuki Motomiya･Ryosuke Ichimura･Satofumi Maruyama･Koichi Nishibe･Akemi Ito (Tokyo City University)･Koji Kikuhara (Waseda University)･Miyuki Usui (NPR-RIKEN)･Yuma Osawa (Tokyo City University)

Hydrogen engines tend to operate with a high air-fuel ratio to prevent abnormal combustion, resulting in lower exhaust temperatures compared to conventional engines. This enables the potential use of high-efficiency thermoelectric devices designed for low temperatures, for waste heat recovery. Temperature at various points on the exhaust system was measured using a hydrogen engine truck during actual road driving. The optimal point for installing the thermoelectric devices was investigated, and electric power generated was estimated.

Analysis Methods of Real-world Ammonia Emissions Using Small Type On-Board Emissions Measurement System

Susumu Sato･Keigo Ashizawa･Chisato Fukunaga (Institute of Science Tokyo)･Noritsune Kawaharada (NALTEC)

In place of the PEMS used for RDE regulations, lightweight and compact on-board emission measurement devices that do not affect the vehicle weight are attracting attention. In this study, the dry-wet correction, delay time correction, and mass emission calculation necessary for analyzing NH3 emission were investigated based on the results of on-road measurements using a compact on-board emission measurement device installed in a gasoline vehicle.

Effect of Precious Metal Species and Ceria-Zirconia Composition on Oxygen Storage Distribution in Three-Way Catalyst

Yuji Tokumasu･Yuki Watanabe (Institute of Science Tokyo)･Hiroyuki Itoyama･Chengwei Huang･Tsuyoshi Ishikawa (Nissan Motor)･Tsuyoshi Nagasawa (Institute of Science Tokyo)

To enhance the performance of three-way catalyst (TWC) and develop a numerical model, elucidating the oxygen release and storage mechanisms is key. In this study, oxygen isotope labeling experiments were conducted using a model catalyst consisting of dense oxygen storage material substrate coated with a precious metal. The effects of the TWC composition, such as the precious metal and the ceria-zirconia composition, on the oxygen storage distribution inside were visualized and analyzed.

Efforts to Create a Desktop Model Calibration for Exhaust Emissions Using Catalytic Reaction Models
-Calibration of Target Air-Fuel Ratio on Engine Start for Hybrid Electric Vehicle-

Tsuyoshi Ishikawa･Atsushi Morohoshi･Hiroyuki Itoyama･Yosuke Kubota (Nissan Motor)

Calibration of the target air-fuel ratio is important for emissions performance, and has been mainly conduct a actual engines until now. In this study, we developed an environment in which the control target value can be combined with the catalytic chemical reaction model, and developed a method to examine the matching value by the model. In this paper, the case of air-fuel ratio compatibility at engine starting is introduced together with the verification results using a high-speed gas analyzer.

Experimental Analysis of Ammonia Generation Characteristics by Heated Wall Under Low Temperature Exhaust Gas Conditions

Tetsu Ishii･Kengo Nakagawa･Eriko Matsumura (Doshisha univ.)

In SCR systems under low exhaust gas temperature conditions, the urea is not decomposed to ammonia completely and the NOx purification rate decreases. In this study, the effects of wall heating control on ammonia production under low exhaust gas temperature conditions through experimental analysis are reported.

Advanced Materials and Regeneration Control for Cost-Effective and Low-Backpressure DPF Systems in On-Road and Off-Road Heavy-Duty Applications

Ryoko Chijiiwa (Corning Japan)･Krishna Aravelli･Suhao He (Corning Inc.)

This study focuses on optimized control strategies for Diesel Particulate Filter (DPF) systems in on-road and off-road heavy-duty applications. It aims to leverage advanced materials to achieve cost-effective aftertreatment design with low-back pressure while complying with global emission regulations. The proposed approach integrates new DPF material designs and optimized regeneration control methods, maintaining filtration efficiency, minimizing pressure drop, and reducing overall system cost. Experimental validation and simulation analyses were conducted to evaluate trade-offs between filtration efficiency, pressure drop, and soot load capacity, providing insights for future emission control technologies in the heavy-duty segment.

Exhaust Gas Velocity Distribution Analysis Method Using Temperature Distribution and Heat Transfer Characteristics of Catalytic Converters

Jiho Cho･Hyungjun Kim･Sungmu Choi･Jaegyung Yoon･Changwan Hong･Sangmin Lee (Hyundai Motor)

This study proposes a method to measure exhaust gas velocity distribution at a catalytic converter inlet by analyzing transient temperature changes during warm-up. Unlike direct velocity measurements, this approach infers velocity profiles from temperature responses affected by thermal capacity. Experiments under various conditions validate its accuracy and feasibility. The method offers a novel way to assess flow uniformity, providing valuable insights to enhance catalyst design and performance.

Development of an Exhaust System Complying with Tier 4 PM Regulations through Study of PM Formation Mechanisms in the Exhaust System

Sungmu Choi･Hyeongjun Kim･Wonsoon Park (Hyundai Motor)

The U.S. Tier 4 regulation imposes a more stringent particulate mass (PM) limit of 0.5 mg/mile, with enforcement scheduled to commence in 2027. The experimental results revealed considerable variability in PM measurements obtained via filter paper, with occasional exceedances of the Tier 4 PM threshold. This phenomenon is hypothesized to result from the interaction between soluble exhaust gases, produced from the catalyst, and condensate water within the exhaust system, leading to PM formation. As exhaust temperatures rise, the evaporation of condensate water is believed to release the formed PM into the exhaust stream. The following strategies can be proposed to comply with Tier 4 particulate matter (PM) regulations: 1) implementation of high-efficiency GPF for PM reduction, 2) Utilization of additional catalyst to mitigate soluble exhaust gases, 3) elimination of semi-volatile compounds deposited in the exhaust system and measurement apparatus that may be converted to PM.

Study on the Degradation Mechanisms of North American Canisters

Seungyub Lee･Keunsoo Kim･Seunghwan Park (Hyundai Motor)

This study analyzes degradation in automotive fuel vapor canisters compliant with North American ORVR regulations. ORVR strictly limits refueling emissions and requires working capacity exceeding non-ORVR systems. Activated carbon drives vapor adsorption, so capacity loss risks noncompliance. We examine whether temperature swings during repeated adsorption-desorption cycles cause material deformation and thermal shock that accelerate degradation. Additional factors, including fuel intrusion and condensation, are assessed for effects on capacity and durability. Finally, we outline research needs to quantify degradation, refine materials and designs, and develop accelerated tests and models that ensure long-term performance, reliability, and regulatory conformity of fuel canisters overall.

Study on the Fatigue Strength of Dissimilar Adhesive Joints between Steel and Aluminum Alloy

Teppei Oe･Teppei Oe (Mazda)･Takahiro Suzuki (Toyota Auto Body)･Kouhei Yamamoto (Yamaha Motor)･Koichiro Oi (Suzuki Motor)･Takefumi Murai (Sunstar Engineering)･Hiroyuki Oguma (National Institute for Materials Science)･Izuru Nishikawa (Osaka Institute of Technology)･Atsushi Sugeta (Hiroshima University)･Yoshihiko Uematsu (Gifu University)

The fatigue characteristics behavior of adhesively bonded dissimilar joints between steel plate and aluminum alloy plate was investigated, covering specimen fabrication, acquisition of fundamental data, and evaluation methodologies. Through these efforts, the influences of adherend stiffness and adhesive-edge geometry on the fatigue strength of dissimilar material joints were clarified. Furthermore, by introducing the stress intensity factor, a unified approach for evaluating fatigue strength was proposed.

Investigation of the Effects of Water Absorption and Post-Absorption Drying on Adhesive Strength

Takahiro Miyawaki (Mitsubishi motors)･Kazuo Hattori (AISIN)･Ryuuta Kubota (Toyota Motor Kyushu)･Takaaki Inoue (Sunstar Engineering)･Masaki Tani (Toyota Industries)･Hiroyuki Oguma (National Institute for Materials Science)･Izuru Nishikawa (Osaka Institute of Technology)･Atsuhsi Sugeta (Hiroshima University)･Yoshihiko Uematsu (Gifu University)

The degradation and control conditions of test specimens required to quantitatively evaluate the effects of adhesive layer thickness and post-absorption moisture content factors considered to influence the fatigue strength of adhesive joints have not yet been established. In this study, we examined specimen fabrication methods using lap shear specimens to quantitatively assess the impact of moisture-induced degradation on fatigue properties. Additionally, we investigated the effects of moisture absorption and subsequent drying on static strength.

Loosening Phenomenon of a Thin Plate Bolted Joint Subjected to Bending Moment

Shoma Osaka･Yutaro Kurabayashi･Shinji Hashimura (Shibaura Institute of Technology)

In our previous study, we have revealed that when a bending moment is applied to a thin plate bolted joint, the reduction of clamping force, that is loosening, occurs even if the bending moment has been released. We investigated effects of various tightening conditions of the thin plate bolted joint, such as the clamping force, plate thickness, and plate width, on loosening.

Influence of Temperature on the Friction of Contact Surface Treated in case of the Bolted Joints

Yukio Morozumi (Toyota Motor)･Yuuya Omiya･Hayate Shimoyama･Shotaro Terao (Kagawa University)

Bolt fastening is a joining technique that relies on frictional force. Since vehicles are sometimes exposed to high temperatures, understanding the friction characteristics at the contact surfaces under such conditions is considered important for ensuring reliability. In this study, a test equipment to measure friction coefficients was developed, and measurements were conducted on specimens with anti-corrosion surface treatment utilized to screw parts. Based on observations and characteristics of the contact surfaces, the influences of temperature are discussed.

Effects of Substrate Surface Roughness and Adhesive Elongation on the Adhesion Strength of Metal-Composite Joints

Go Yoshida･Souichiro Nishino (Ibaraki University)

With the progress of multi-material usage in structural components, adhesive bonding has gained attention as a joining technique for metal materials and polymer composites. In this study, the effects of substrate surface roughness and adhesive elongation on adhesion strength were investigated.

Evaluation of Fatigue Crack Propagation Characteristics under Different Fracture Modes in CFRP Bonded Joints with Urethane Adhesive

Toshiharu Hama (Hiroshima Univ)･Toshiaki Nakamaru･Kousuke Satou (Nissan Motor Co. , Ltd)･Yuki Ogawa･Hiroyuki Akebono･Atsushi Sugeta (Hiroshima Univ)･Takeshi Ogawa (Aoyama Gakuin Univ)

To achieve CN, the application of lightweight materials such as CFRP is expanding in automotive body structures. Adhesive bonding, which enables joining dissimilar materials, is also gaining attention, necessitating the establishment of CFRP bonded structure and its fatigue charactreristic. In this study, to establish fatigue design guidelines for CFRP bonded joints with a urethane adhesive, fatigue crack propagation characteristics for different fracture modes were elucidated.

Evaluation Method of Crack Propagation Life of CFRP Bonded Structures Using Urethane Adhesives

Takuya Yuasa (Nissan Motor)･Noriyuki Kawai (Mazda)･Takamitsu Nishiya (Isuzu Motors)･Hiroyuki Sato (PRESS KOGYO)･Yoshiki Yokote (Hino Motors)･Kousuke Satou･Toshiaki Nakamaru (Nissan Motor)･Takeshi Ogawa (Aoyama Gakuin University)

Crack growth behavior of CFRP adhesive bonded structures, in which most of the whole life is occupied by crack growth of urethane adhesive, was clarified by experimental measurement and finite element analysis of hat shaped torsional specimens simulating actual car body structure. In addition, the fracture mechanics analysis was conducted, and verified the evaluation criteria by comparing with lap shear specimens and I-shaped bending specimens.

Development of an Evaluation Method for Component Performance Considering Material Property Variations in Aluminum Die-Cast Parts Using Machine Learning

Yuki Okumoto･Kyosuke Hamaishi･Takahiro Izawa･Ichiro Kono･Taichi Hirakawa･Hiromasa Honji･Nobuyuki Oda･Manabu Tatsuda･Kosuke Kojima･Ryo Yamamoto (Mazda)

In recent years, the application of high-pressure die-cast aluminum (HPDC) to vehicle body structures has expanded. Since material variations occur during the manufacturing process, it is essential to determine specifications with sufficient consideration of their impact on vehicle performance. In this study, we developed a CAE methodology that predicts material properties for each component using machine learning and integrates these predictions with crash analysis.

Fatigue Evaluation and Rapid Fatigue Strength Determination of C-SMC Using Thermoelastic Temperature Variations

Atsushi Akai (Kyoto University of Education)･Yukihiro Hamada (Toyota Motor)･Yasumoto Sato (Toyota Central R&D Labs.)･Atsushi Mikuni (Toyota Motor)

Recently, carbon fiber sheet molding compound (C-SMC), which is a discontinuous carbon fiber-reinforced polymer composite fabricated via sheet molding compound methods, has attracted increasing interest in the automotive industry. Knowing the fatigue strength of a material is indispensable for structural design; however, its determination is time-consuming and costly. In this study, fatigue evaluation and rapid determination of fatigue strength using thermoelastic temperature variations are performed on C-SMC.

Development of Open Top Air Body Structure Using Hot Blow Method

Do Hoi Kim･Kang Chul Lee (Hyundai Motor)･Golam Ahmed･Eddings Forrest･Dhananjay More･Vinaya Kumar Rachala (Hyundai America Technical Center Incorporation)

This study develops an Open Air Top vehicle body using hot blow forming, enabling detachable roofs with improved rigidity and safety. Two designs were evaluated: a Close Type with integrated high-strength pipes and an Open Type featuring exposed pipes for enhanced openness. Structural and collision analyses showed that despite reduced roof rail cross-sections and absence of the roof panel, up to 60% of base body stiffness was achieved, with reinforcements improving collision performance. Manufacturing feasibility was confirmed through prototype development. This research establishes hot blow forming as a lightweight, strong, and modular approach that meets consumer and safety demands.

Consideration of General Waveform creation method for Road Simulator Durability Test
-Development of Numerical Simulation Modeling Based on a Comparison of Real Vehicle Vibration Testing Accounting for Four Wheels Phase Differences and Numerical Simulations-

Tomoyuki Kita (PRESS KOGYO CO., LTD)･Atsuhito Nakamura (Mitsubishi Fuso Truck and Bus)･Ryo Okabe (Mitsubishi Motors)･Mitsuo Harino (Suzuki Motor)･Tetsu Oami (Toyota Motor)･Yuki Ogi (Toyota Auto Body Co., Ltd)･Masahiro Kajihara (Honda R&D Co., Ltd.)･Hisami Oishi･Kousei Fukatsu･Yusuke Kasai (Kogakuin University)

To investigate the influence of vehicle inputs on the four body modes, a four-wheel vertical excitation experiment and a numerical simulation using a four-wheel, seven degrees-of-freedom model were conducted. As a result, it was confirmed that each mode exhibited a different response due to the effect of sprung mass resonance. Furthermore, the necessity of four-wheel validation was identified to investigate the influence of suspension characteristics on vehicle response.

Consideration of General Waveform Creation Method for Road Simulator Durability Test
-Comparison and Investigation of Time History Waveforms Derived from Road Surface PSD and Measured Time History Waveforms-

Takayuki Nakamura (Toyota Motor)･Atsuhito Nakamura (Mitsubishi Fuso Truck and Bus)･Kouki Satou (SUBARU)･Kohei Mino (Honda R&D Co., Ltd)･Yusuke Suzuki (Daihatsu Motor)･Ryo Okabe (Mitsubishi Motors)･Noriyoshi Ohira (MTS Japan Co., Ltd.)･Kosei Fukatsu･Yusuke Kasai･Hisami Oishi (Kogakuin University)

A method for separating operational input from market measurement data was refined, and Power Spectral Densities (PSDs) for four road types—highway, normal road, winding road, and rough road—were computed. The obtained PSDs were found to be equivalent to those reported at the 2021 Symposium and the 2023 Spring Conference. It was demonstrated that Unevenness values increased in the order of highway, normal road, winding road, and rough road, which was consistent with the expected characteristics of each surface.

Development of a Method for Predicting Underbody Stress from Road Interference

Yoichiro Okuhira･Takanori Ogata･Takeyuki Harada･Masao Matsumura･Yuya Yamaki (Toyota Motor)

In recent years, vehicle electrification and low-floor design requirements have increased the need for analyzing road surface interference with underbody components. While nonlinear finite element analysis is widely used for short-duration impact phenomena, practical challenges remain when interference occurs in conjunction with vehicle dynamics. This study presents a hybrid approach that combines multibody dynamics analysis with localized nonlinear deformation modeling applied only to interfering components. The proposed method enables accurate and efficient prediction of interference loads within significantly reduced computational time.

Set-based Design Approach for Vehicle Body Reliability Development Using Bayesian Active Learning

Kohta Miyaki･Koji Nishikawa･Tomotaka Sugai (Toyota Motor)

In defining the target strength of the vehicle body, the maximum load that the vehicle body can endure is estimated by utilizing a surrogate model based on machine learning, which is created from the vehicle body input from rough-road simulations. However, the response surface of the vehicle body input has a strong nonlinearity, and in utilizing the surrogate model for this purpose,It is essential to accurately predict the maximum values within various ranges of design variables. This paper proposes a new method to learn by focusing on the vicinity of the peaks for responses that are nonlinear and possess multiple local maxima.

Numerical Evaluation of Single Lap joints Bonded with Adhesive

Hirofumi Sugiyama (University of Yamanashi)･Shigenobu Okazawa (University of Yamanashi/Diver Technology)

This study presents a numerical evaluation method for adhesive-bonded single-lap joints. A previously proposed numerical method was capable of simulating crack propagation, and its applicability had been confirmed under shear deformation. However, the conventional model had limitations in representing the complex mechanical behavior of the adhesive layer and cracks occurring in arbitrary directions. The present study extends this approach to evaluate the adhesive region under bending loads. Numerical simulations of single-lap joints were conducted, and the results demonstrate the capability of the proposed method to reproduce the joint strength and crack behavior.

Interactive Extraction of 1D-CAE Modeling Requirements and Determination of Model Configuration using Generative AI

Kyohei Naito･Junichi Ichimura･Yuki Wakimoto (NewtonWorks)

We address the modeling process of idealizing real systems according to analysis objectives, which often becomes superficial due to time constraints. We propose a methodology to define the required information and extract it interactively using Generative AI. We discuss the process of eliciting appropriate assumptions and abstraction levels through dialogue, structuring them into engineering-consistent specifications to achieve model definitions that are both efficient and capture the essence.

Automated Implementation of 1D-CAE Models and Support for Checking Consistency with Requirements

Junichi Ichimura (The Open University of Japen)･Kyohei Naito･Yuki Wakimoto (NewtonWorks)

We discuss the automated implementation of 1D-CAE models based on input specifications and the method to support checking their consistency with requirements and physical feasibility. The AI analyzes and reports reasons for discrepancies between results and specifications. We propose a Human-in-the-Loop process where engineers verify specification conformity based on these reports and determine refinement strategies to optimize the model.

Development of MBD Method for Global Design Optimization Using Cross-Domain Model
-Model Development and Application to Vehicle Development Considering Power Management, Thermal Performance, Vehicle Motion Performance, etc-

Shigemitsu Takahashi･Aoto Utsumi･Yudai Matsumoto･Masayuki Tani･Masayuki Kiyono (Nissan Motor)

This paper describes the outline of the cross domain model CAEM (Collective Automotive Engineering Model) and its application to vehicle development MBD. Focusing on energy flow, a model that can be predicted from completely identical design information in an integrated environment of power management, thermal performance, and vehicle motion performance is developed. And, it is possible to do module selection considering across domains trade-offs.

Virtual Validation Methodology and Credibility Assessment for Automated Driving Systems with Applications to NCAP 2029

Reza Rezaei･Christian Lang･Kento Fukuhara･Gnana Prakash Reddy Madduri･Abhishek Singh Kudavale (IAV)

This paper presents a methodology for virtual validation and credibility assessment based on EU 2022/1426 and ISO 3540x. The methodology incorporates co-simulation for overall system modeling and validation of automated driving (AD) Level 3+ systems, integrating evidence-based real-world scenarios. Furthermore, it is designed to align with NCAP 2029 requirements, ensuring applicability for virtual testing and crash avoidance safety rating programs. By combining advanced physics-based validation techniques to ensure simulation credibility with a novel LLM-based scenario creation, the framework supports the virtual development and validation of AD systems, addressing future needs for cost reduction, reliability, and extensive mileage testing.

An Integrated Model-Based Development Framework for Automotive Thermal Energy Systems

Choo Bumseok･An Hyunmo･Jo Chanwoong (Hyundai Motor)

This study introduces an integrated model for automotive thermal energy systems for model-based development (MBD), aligned with ISO 26262 standards. The model consolidates system data such as configurations, functions, and performance into a unified digital platform to enhance collaboration. A structured development process is proposed using tools like MathWorks System Composer and GT-SUITE, with automation for thermal flow analysis. The approach is validated through a Rankine cycle case study, demonstrating improved consistency and efficiency.

Issues in Microalgae Biofuel Production and Efforts to Solve Them（2nd Report）

Shinichiro Maeda･Kazuo Ichikawa･Takehisa Koroki･Hiromi Tanaka (Mazda)･Kumiko Okazaki (Hiroshima University)･Yoshitaka Nishiyama (Saitama University)･Satoshi Nakai･Takashi Yamamoto (Hiroshima University)･Hiroyuki Ota (Phytolipid Technologies Co., Ltd.)･Atsushi Sakamoto (Hiroshima University)

Microalgae biofuels, characterized by high productivity and non-competition with food resources, are regarded as promising candidates for next-generation carbon-neutral liquid fuels. Mazda has been conducting research on fuel production using the marine microalga Nannochloropsis through industry–academia collaboration. Previous reports have described the modeling of processes from cultivation to fuel production, the identification of bottleneck areas, and efforts undertaken to resolve them. This paper reports on the identification of bottleneck areas in CO₂ emission reduction and presents initiatives that utilize waste energy and waste materials to address these challenges.

Evaluation of Base-Fuel Dependence on Ignition-Suppression Effect of ETBE Using a High-Pressure Shock Tube

Ken Satokawa･Tomohiro Hamasaki･Reina Okamura (Sophia University)･Akira Miyoshi (Hiroshima University)･Kazuo Takahashi (Sophia University)

In order to realize a carbon-neutral society, the phased introduction of biofuels is being considered in Japan. We have previously focused on the ignition suppression effect of ethanol and clarified its dependence on the base fuel. In the present study, we investigated the interaction between ETBE and the base fuels through ignition delay measurements using a high-pressure shock tube, and compared the results with those of ethanol.

LCA Prediction of Lithium-Ion Batteries for Electric Vehicles Based on the Paris Agreement

Keiichiro Sano･Yuuri Ujike (Kanto Gakuin University)･Yasuhiro Oi (Former Kanto Gakuin University)･Hiroshi Yagita (Nippon Institute of Technology)･Junichi Kasai･Katsuhiko Takeda (Kanto Gakuin University)

CO2 emissions during power generation vary from country to country. In this study, based on the Paris Agreement, the LCA was used to predict the reduction in CO2 emissions over lifetime traveling of lithium-ion batteries for electric vehicles up to 2050. It was estimated that, in terms of lifetime use to date, hybrid vehicles are as environmentally friendly as or better than electric vehicles, but that electric vehicles will be better for new vehicles in the future.

Hydrogen Generation via Steam Methanol Reforming for Sustainable IC Engine Transportation- A Simulative Investigation

Bhawandeep Sharma･Yuchen Liu (Guangdong Technion Israel Institute of Technology, Shantou , China)･Devendra Yadav･Michael Patrascu (Technion Israel Institute of Technology, Haifa, Israel)･Madan Kumar (Guangdong Technion Israel Institute of Technology, Shantou , ChinaGuangdong Technion Israel Institute of Technology, Shantou , China)

This work investigates alternative fuels, specifically methanol and hydrogen. Given the storage and safety challenges associated with hydrogen, this work focuses on its continuous onboard production via steam methanol reforming, using IC engine exhaust heat as the driving energy source. The approach utilises a catalysed reformer, with exhaust gases routed to enable stable hydrogen production rates of up to 2 kg/h, supporting dual-fuel engine operation. Numerical simulations demonstrate a reliable hydrogen yield suitable for secondary fueling. Future work will experimentally validate the benefits of dual-fuel operation, including improved combustion efficiency and reductions in NOx and CO emissions.

Analysis of Accidents Involving Vehicles with Automatic Emergency Call Systems (D-Call Net) and Further Utilization

Masayuki Shirakawa･Toru Kiuchi (Institute for Traffic Accident Research and Data Analysis)

One effective way to reduce traffic accident fatalities is through an automatic emergency notification system (D-Call Net). The number of vehicles compatible with the system is increasing year by year and is continuing to expand. We will analyze the actual accident situations involving response vehicles and present their effectiveness and areas where further expansion of application is desired. We will also introduce examples of successful use of D-Call Net from actual accident investigations.

Study on Actual situations of D-Call Net by Matching Automatic Notification Data with ITARDA Macro Data

Toru Kiuchi (ITARDA)･Testuya Nishimoto (Nihon University)･Nobuo Saito･Ichiro Ando (JAPAN MAYDAY SERVICE)･Eiko Kagesawa･Mayu Ishii (ITARDA)

In recent years, the number of automatic notifications has dramatically increased due to the spread of vehicles equipped with D-Call Net. The authors were able to obtain notification data from three new OEMs in addition to the existing one. Therefore, we conducted a new effect study by matching the 2023 data with ITARDA macro data. This time, we focused on the fatal and serious injury rate and analyzed the actual situation.

In-Depth Study on Pedestrian and Cyclist Crashes Resulting in Transport to Emergency Hospital and Verification of Injury Prediction Algorithms for Vulnerable Road Users

Tetsuya Nishimoto (Nihon University)･Tomokazu Motomura (Nippon Medical School)･Nagaoka Yasushi (Toyota Motor)

A study was conducted on approximately 200 cases of pedestrians and cyclists versus motor vehicle accidents where victims were transported to an emergency hospital. The results of analyses concerning collision speed, injured body regions, AIS and so on. Furthermore, injury severity was predicted using our injury prediction algorithms for pedestrian and cyclist, and consideration was given to automatic emergency notification systems for vulnerable road users.

Artificial Intelligence as a Catalyst for Next-Generation Emergency Call Systems

Hamma Tadjine･Amine Kaddache (IAV)･Isao Hasegawa (IAV Japan)

Advanced emergency call systems currently transmit basic vehicle data during accidents. To enhance passenger safety, new features focus on improved data collection aligned with NENA2 and NG-AACN standards, considering in-vehicle architecture and communication protocols. The goal is to provide precise information about occupants and surroundings for better rescue operations. AI integration boosts efficiency and effectiveness, optimizing eCall systems through rapid data analysis and prioritizing calls by severity. AI enhances design and operational capabilities, enabling automated data processing and swift emergency assessment. Predictive analytics foresee potential emergencies, supporting proactive measures and strategic resource allocation for high-risk scenarios.

In-Depth Investigation of Traffic Accidents with Medical and Engineering Network by ITARDA

Sentaro Terakado･Takehiro Tsuji･Tatsuya Ito (Institute for Traffic Accident Research and Data Analysis)･Kazuaki Shinohara (Ohta General Hospital Foundation)･Toru Kiuchi (Institute for Traffic Accident Research and Data Analysis)

ITARDA has been conducted in-depth investigation of traffic accidents with medical and engineering network in order to obtain basic data that contribute to mitigate injuries caused by traffic accidents since 2016. This investigation is consortium by ITARDA, Hospital and vehicle manufacturers, traffic accidents in around Tokyo were investigated. Occurrence mechanism of injury due to traffic accidents was discussed by consortium members including medical professionals and engineers based on medical images and vehicle damage. In this report provides the results of in-depth investigation of traffic accidents.

Development of the Traffic Offense Traits Scale (TOTS) for Recidivism Risk Assessment

Masae Kojima (Nagoya University)･Kojiro Shojima (National Center for University Entrance Examination)･Kazuko Okamura (National Research Institute of Police Science)･Chieko Nishizawa･Shota Matsubayashi (Toyota Technical Development)･Kazunori Ban (Toyota Technical Development / Nagoya University)

This report developed the Traffic Offense Traits Scale (TOTS) to enable early identification of repeat traffic offenders and effective intervention. Exploratory factor analysis (EFA) with general drivers from a web survey and confirmatory factor analysis (CFA) with traffic offenders from a course designed for minor traffic offenders established a 24-item scale with a seven-factor structure. The scale demonstrated good reliability and validity across both samples, confirming its applicability for assessing psychological characteristics underlying repeated traffic offenses.

Analysis of Characteristics of Repeated Traffic Offenders

Shota Matsubayashi (Toyota Technical Development)･Masae Kojima (Nagoya University)･Chieko Nishizawa･Kazunori Ban (Toyota Technical Development)

We analyzed the relationship between the characteristics of repeated minor traffic offenders and the details of their offences. The results showed that characteristics such as lack of cautiousness were related to specific types of offences. Their patterns in these characteristics varied among offenders, suggesting that the presence of qualitatively different groups within the population. We discussed the need to improve the training course based on the offenders' characteristics.

Analysis of Self-evaluation and Traffic Behavior in Traffic Offender Course

Chieko Nishizawa (Toyota Technical Development)･Masae Kojima (Nagoya University)･Shota Matsubayashi･Kazunori Ban･Eisuke Kobayashi･Kazunori Ban (Toyota Technical Development)

To reduce traffic accident risks, it is essential to make drivers recognize these risks as their own concern and encourage behavioral change. In this study, we implemented an educational program incorporating simulator-based training and hazard prediction training in a course designed for minor traffic offenders. This report presents the results of analysis examining changes in self-evaluation and traffic behavior following educational program.

Development of a Method for Evaluating Muscle Burden During Driving Operations
-Steering Emergency Avoidance Maneuver-

Akito Onami･Takeru Higuchi･Naoya Yamakawa (Suwa University of Science)･Masashi Makita (Teikyo University)･Hiroshi Kuniyuki (Suwa University of Science)

In this study, a muscle burden assessment method using dumbbells to stably evaluate driver muscle burden during emergency avoidance maneuvers via steering. The results indicated that EMG measurements during lifting of a fixed-weight dumbbell, which provides a load equivalent to that required for driving operations, can estimate maximum muscle capacity and stably evaluate muscle burden during steering operation.

Survey on Naturalistic Driving Behavior of Motorcycles on Hilly and Mountainous Roads

Shun Nagao･Shion Sato･Yuta Katayama･Hiroshi Kuniyuki (Suwa University of Science)

In this study, the naturalistic driving behavior of riders on hilly and mountainous roads was investigated to examine factors contributing to motorcycle single-vehicle accidents. The results revealed differences in motorcycle body lean angle and rider upper body movement depending on the direction and curvature of curves. The way the center of gravity of the motorcycle body and upper body was balanced against curves was different. This difference in driving behavior is considered one of the factors contributing to accidents.

Risk Assessment of Collisions between High-Velocity Runaway Vehicles and Motorcycles/Motorized Bicycles on Public Roads
-Risk Assessment based on the Personal Injury Level of Motorcycle/Motorized Bicycle Riders-

Yasufumi Se (Fukuyama University)

Accidents caused by high-velocity runaway vehicles include not only vehicle-to-vehicle collisions and pedestrian collisions, but also accidents in which motorcycles and motorized bicycles are victims. This paper analyzes traffic accident statistics data on motorcycles and motorized bicycles and attempts to numerically clarify the risk of accidents caused by high-velocity runaway vehicles based on the relationship between injury severity and collision velocity.

Development of a Driving Simulator for Safe Driving Education to Prevent Rear-End Collisions and Hurried Driving

Masaki Hayashi･Koshi Miyazaki･Kazuaki Goshi･Yasuaki Sumida (Kyushu Sangyo University)･Katsuya Matsunaga (Kyushu University)

To prevent car accidents, drivers must learn to keep a proper following distance and recognize that travel time does not significantly decrease even with hurried driving because of traffic signals and other vehicles. This study developed a driving simulator designed to provide safe driving education that integrates both rear-end collision prevention and the reduction of hurried driving behavior, through collision experience and comparisons of arrival times and safety across multiple driving trials.

Relationship Between in Single-Vehicle Accidents Caused by Gear Shift Errors

Yoko Kato･Yasuhiro Matsui･Michiaki Sekine (NALTEC)

In a previous report, it was revealed that drivers involved in single-vehicle accidents caused by gear shift errors sustained severe injuries. One contributing factor may have been the non-use of seat belts at the time of the accident. In this research, these accidents were analyzed with a focus on seat belt use, including the injury level, objects causing injury, and injured body parts.

An Investigation into the Causes of Wheel Detachment Accidents in Heavy Trucks

Soichi Hareyama (Tokyo Metropolitan University)

Accidents involving wheel falling off in heavy-duty vehicles continue. This study examines the causes of wheel bolt loosening based on the characteristics of the torque method (calibrated wrench method), and examines and proposes measures to prevent loosening.

Assessment of the Impact of Energy Transformation Accompanying Decarbonization on 2050 Air Quality

Yusuke Yasukawa･Hiroyuki Yamada (Tokyo Denki University)･Yoshiaki Yamadaya (Ibaraki University)･Tazuko Morikawa･Masamitsu Hayasaki (JARI)･Kotaro Tanaka (Ibaraki University)･Shinichiro Okayama (Motolity)･Yoshiaki Shibata (Institute of Integrated Atmospheric Environment)･Hiroe Watanabe (Nissan Motor)･Toru Kidokoro (Toyota Motor)

Based on the Ministry of the Environment's “2023 Progress Report on Global Warming Countermeasures,” revisions were made to emissions of various pollutants from stationary sources under the Seventh Energy Basic Plan previously formulated. Using these results, we estimated the impact of pollutants from automobiles on air quality once a carbon-neutral society is achieved and conducted atmospheric simulations for that scenario.

Challenges and Solutions for High-Accuracy Exhaust Gas Measurement in Carbon-Neutral Fuel Applications

Yosuke Kondo･Yuichi Mori (HORIBA)

Research and development aimed at applying carbon-neutral (CN) fuels to mobility systems has been increasingly active. In general, the combustion of CN fuels produces higher water vapor concentrations in the exhaust gas compared with conventional fossil fuels, thereby imposing additional technical requirements on exhaust gas measurement systems. This paper discusses methodologies for achieving high-accuracy exhaust gas measurements, with particular emphasis on CN fuels and upcoming emission regulations.

Soot Emission Characteristics of Three-Component Gasoline Surrogate/Ethanol Blended Fuels

Jun Hashimoto･Kazumasa Ito･Shunya Matsumae (Oita University)

Ethanol blending is generally expected to reduce soot, yet recent studies show nonlinear responses depending on conditions and reactants. In this work, ethanol was blended with a three-component gasoline surrogate, and soot volume fractions and size distributions were systematically measured. The dataset was then used to validate a soot prediction model, providing new insights into the mechanisms governing soot formation under fuel–blend variations.

A Pollution Monitoring Method for Dilution Tunnels toward low-concentration PM Regulations

Suguru Fukushima･Taisuke Yoshida･Erika Matsumoto･Yoshinori Otsuki (HORIBA)

As regulations on particulate matter (PM) emissions from automobiles and other sources become stricter, one of the challenges in measuring low-concentration PM is reducing background PM. A measurement method using image processing was compared with the conventional filter weight method to verify its usefulness as an efficient dilution tunnel pollution monitoring system. As a result, we get a correlation coefficient of 0.95 or higher and a resolution equivalent to 0.02 mg/mile.

Articulated Vehicle Detection via Learning Inter-Object Relationships using GNN in LiDAR Point Clouds

Riku Kagohashi･Keigo Hariya･Keisuke Yoneda･Yukiya Fukuda･Naoki Suganuma (Kanazawa University)

Detecting articulated vehicles in LiDAR point clouds suffers from low accuracy due to geometric complexity and information loss caused by self-occlusion. This study proposes an object detection model that learns inter-object relationships using Graph Neural Networks (GNN). By jointly considering spatial arrangement and contextual information in addition to individual geometric features, we aim to improve the detection accuracy of articulated vehicles.

Self-Supervised Pre-Training for Generalizable Feature Extraction from 4D Imaging Radar Point Clouds

Takumi Takai･Keisuke Yoneda･Keigo Hariya･Haku Shinoda･Yukiya Fukuda･Naoki Suganuma (Kanazawa University)

4D imaging radars excel in environmental robustness and long-range detection. However, their point clouds contain abundant noise and are sparse, making challenges for tasks such as object detection and self-localization. In this study, we build a self-supervised pre-training model based on a masked reconstruction task to extract generalizable features from radar point clouds, and evaluate its effectiveness in object detection.

A Study on the Finite Element Analysis for the Optimized Design of Bumper Towing Cap for Vehicles

Gyuho Shim･Teawon Kim (SECO ECOPLASTIC)･Geonhee Cheon (SECO SEOJIN)

The bumper towing cap for automobiles is a part that is mounted on the bumper of the cap type as well. It prevents exposure to the hole where the towing screw is mounted. It also aims to maintain the design. When the toeing cap is designed robustly, it is difficult for the user to remove it. Conversely, when designed loosely, it can be removed while driving. Therefore, in this study, a study on finite element analysis for the optimization design of the toeing cap was conducted.

Integrated CAE Framework from Manufacturing Processes to Performance Prediction

Hiroyoshi Horibe･Satoshi Yamamoto･Takayuki Fujii･Kazumasa Usui･Ichiro Tanaka (Honda R&D)

Simultaneous consideration and acceleration of vehicle body structure and manufacturing methods, which are changing due to electrification, are required. A mechanism was developed to accurately transfer physical property changes necessary for performance prediction between manufacturing processes and reflect them in the performance model. Changes occurring in pressing, welding, and drying processes were generated and transferred, and their impact on performance prediction results was verified using test pieces, reporting examples of effectiveness.

Relationship between Structural Complexity, Objective Function, and Smoothness in Topology Optimization

Akihito Takeda (SCSK Minori Solutions)･Hiroshi Koizumi (Mizuho Bank)･Shinichi Maruyama･Kazuhiro Izui･Shinji Nishiwaki (Kyoto University)

Topology optimization provides a high degree of design freedom among structural optimization methods. This study investigates how varying computational parameters affect the relationships between optimal shape complexity, objective function value, and smoothness, represented by surface area. Results indicate that increased structural complexity improves objective function values, while higher smoothness is associated with simpler shapes.

Developing of an Geometry-Aware AI model for Predicting Stress Distribution in Aluminum Wheels under Impact

Changgon Kim (Hyundai Motor)･Zeqing Jin･Bowen Zheng (University of California, Berkeley)

This study proposes a geometry-aware Graph Neural Network (GNN) model for predicting stress distributions under dynamic impact on aluminum wheels. The model incorporates a weighted loss function and an edge reconstruction technique to improve accuracy in stress concentration regions. Using high-fidelity 3D finite element data from 85 wheel designs, we applied edge augmentation to enhance generalization with limited samples. The GNN model achieved a MAPE of 7.0% in critical regions, significantly reducing computation time compared to conventional FE analysis. This results demonstrate the feasibility of using GNNs for early-stage structural performance prediction in automotive development.

Relationship between Void Distribution Function of Soft Polyurethane Foam and Mechanical Property (Compression Force - Displacement Characteristic)(Second Report)
-Methodology Verifications, Validations and Improvements-

Minoru Inoue (Mazda / Kagawa Univ. / Hiroshima Univ.)･Keisuke Suzuki (Kagawa University)･Hiroyuki Ito (TOYO SEAT Co.Ltd.)

In the first report, CAE methodology to evaluate mechanical properties (compression force – displacement characteristics, hereafter F-S characteristics) of the soft urethane foams using void distribution function was presented. In this second report, verifications and validations for the developed CAE methodology described in the first report were done and then the studies on F-S characteristics and the ability to control F-S characteristics of the soft urethane foams by means of the developed CAE methodology are investigated and presented.

Power Tailgate Economical Type Optimization Development

Sangwook Lee･Sangyoung Im･Joonhyuk Kang･Taenam Jung･Junhyuk Kim･Jiho Choi (HYUNDAI)･Kyuwon Cho (Edscha PHA)

To enhance profitability through securing cost competitiveness, we aim to develop an economical power tailgate (PTG). The economical type consists of a spindle drive and gas lifter, designed to achieve the dual goals of cost reduction and performance enhancement. In this study, we applied new logic that resolves inconsistencies in the existing logic, ensuring the safety of the PTG and improving its marketability. Furthermore, various experiments were conducted to define adverse environmental conditions and verify the required performance of the PTG. Through this development and research process, we expect to significantly increase profitability by expanding the application of economical PTGs to various vehicle models in the future.

A Study on the Opening Force of a Charging Door

Yungyeom Kim･Joonhyuk Kang･Seokhan Kong (Hyundai Motor)

This paper is a study on the opening force of electric charging doors. According to the recent IQS results, there were complaints regarding the opening force of the electric charging door. I researched the factors influencing the opening force of the electric charging door system and checked the degree of influence of each factor. To reduce the opening force, I conducted a study to optimize the cross section of the sealing and overslam bumper. As the application of electric charging doors will be expanded in the future, it is intended to help set the opening force.

A Study on the Application of A-SEG Cladding Options
-Productive and Cost-saving Approch-

Hyeonggeun Jo (Hyundai Motor)

Introduce how to optionally operate cladding at A-SEG. It can expand the customer's choice and provide high-quality cladding vehicles. Design and Engineering elements to be considered in option application of cladding are presented.

A Study on the Development of Front Radar Cover Technology for Autonomous Vehicles

Juhwan Park･Wanho Son･Gyeomson Seong (SECO ECOPLASTIC)･Sunghoon Jung (INTOPS)

Smart Cruise Control (SCC) uses radar to detect preceding vehicles, so the SCC cover must protect the sensor while maintaining radar transmittance. If scratches occur on the cover surface, transmittance decreases and the performance and reliability of autonomous driving deteriorate. This study proposes an SCC cover structure that combines a self-healing polyurethane layer capable of recovering surface damage with a design film that provides a three-dimensional appearance. The proposed concept aims to improve scratch durability and exterior quality while enabling a more efficient manufacturing process with reduced time and cost.