Construction of a One-platform Analysis Technology for Fluid and Structural Analysis (First Report)

Hiroshi Kuribara･Haruka Egami (Honda Motor)･Dianxiang Xiang･Anh Viet Nguyen･Nam Ha Tran (TechnoStar)

In this research, we tried to construct a technology that can efficiently create a model for thermal fluid analysis based on the mesh used for structural analysis. In this paper, we introduce the constructed technology and report on the accuracy of the analysis and the reduction of the analysis lead time when the constructed technology is applied to a temperature prediction analysis of motorcycle exhaust system that takes into account the internal gas flow.

The Development of The Testing Method by the Connection between Driving Simulator and Powertrain Test Bench for Multi-function Synchronous Vehicle Development

Shoichi Ishigaki･Takuya Kusakabe･Hiroshi Sho･Yasuhiro Hiasa･Ryutaro Moriguchi･Yuki Iizawa (Toyota Motor)

We've developed the testing method to realize the synchronous development of the vehicle functions for steering stability, drivability, fuel consumption, noise harshness (NVH) by the connection between a driving simulator and a powertrain test bench. By replacing the actual powertrain and ECU from the part of the model for the driving simulator as a high accurate model, the simultaneous evaluation can be achieved to calibrate both the driver's sensation with the driving simulator and the driving control with the powertrain test bench.

Introduction of Agile Development Technique using New Segmented Mock-up Model with Aerodynamic Noise as Example

Takahiro Nakajima (Honda Motor)･Takuya Iso (Auto Technic Japan)･Sanu Kimu (Persol Cross Technology)

In automotive development, parts such as A-PLR and door mirrors need to balance design and performance, and it is necessary to quickly provide performance insights into the design.
To address this issue, the authors carried out agile development by making part of the car body mock split into pieces, allowing for recombination with parts created using stereolithography.
In this lecture, we will introduce this development method.

Development of Pedal Robot for Vehicle Testing on Chassis Dynamometer

Daeyup Lee (Inha Univeristy / SPLT)･Byeonghee Choi (Inha Univeristy)･Sungwoon Choi (Inha Univeristy / SPLT)･Jimyeong Kang (Inha Univeristy)･Yechan Jo･Hyunwoo Shin (Inha Univeristy / SPLT)･Seoyeon Jeon (Inha Univeristy)･Jongtae Lee･Jongmin Kim･Keonwoo Kang･Jaesik Shin (National Institute of Environmental Research)･Hiroaki Suzuki･Sohju Tominaga (Japan21)

The use of test robots is increasing in automobile tests using chassis dynamometer such as driving tests of electric vehicles. Automotive test robots on the market are known to have problems such as inconvenience in use, installation time, and calibration time due to changes in vehicle type. This study conducted research to develop an automobile test robot with improved ease of use. In order to develop a test robot with pedal movements similar to human driving movements, a pedal robot capable of manipulating the brake pedal and accelerator pedal with a three-degree-of-freedom structure was developed and its performance was evaluated.

Development of Vehicle's Body for Ride Comfort by Actual Driving Simulation

Tomoya Aou･Takayoshi Shigihara (Toyota Motor)

In terms of the ride comfort of a car, recently, a vibration phenomenon in the high frequency range, which is expressed as "texture", has been pointed out. In the high frequency range, there are many elastic resonances of the body.
In this paper, we analyzed the vibration mode of the body during actual operation using an actual driving simulation. The fundamental weaknesses of the body structure were clarified, leading to structural changes including production process changes.Improvements in "texture" were confirmed in the actual vehicle.

Multidisciplinary Design Method for Off-road Vehicles using Differential Evolution Based Adaptive Sampling

Hiroaki Kawamura･Kazuki Tsuda･Tomotaka Sugai･Kohei Shintani･Koji Nishikawa (Toyota Motor)

The suspension characteristics that enhance ride vomfort may conflict with the abillity ot absorb the substantial inpt loads from the road surface, especially when traversing rough terrains in off-road vehicles, such as overcoming rocks and other obstacles. To achieve optimal performace across various indices, we have traditionally relied on trial-and-error methods to find the optimal combinations of design variables. In this paper, we introduce a novel data-driven set-based design approach, employing the differential evolution method．

Development of Automatic Hood Mastic Sealer Arrangement Technology Considering Manufacturing Constraints and Performance Requirement

Noriko Ohtsuka･Hiroaki Onodera･Mashio Taniguchi･Masatake Kimura (Toyota Motor)

Currently, to meet tension stiffness target of the hood, CAE is used repeatedly to determine suitable mastic sealer arrangement. Several complex constraints and combination of the constraints needed for manufacturing require numerous cases of simulation. In this research, we developed a design technology that can rapidly generate multiple arrangement patterns using machine learning. Using this technology, it is expected to reduce simulation costs which will improve the efficiency of the hood development process.

Development of Prediction Method for FDS (Flow Drilling Screw) Joint Rupture Phenomenon using Machine Learning

Kojiro Chujo･Hiroshi Sato･Yoshiteru Ishibashi･Hisashi Ihara･Hisahide Matsuoka (Nissan Motor)

FDS joint is increasingly being used because it can be used to joint aluminum materials to each other and to joint different materials such as aluminum and steel materials.
In this report, we report a case study in which a machine learning model was created based on the result of test piece for the purpose of reproducing the collision phenomenon in CAE, and the accuracy was verified for estimating the breaking load and failure mode.

Development of CAE Models of Arc Welds Including Aluminum Casting

Yuri Ichikawa･Kazushi Urakawa･Eita Niisato･Hiroaki Kawamura･Toshiyuki Isono (Toyota Motor)

Aluminum castings are used for the body frame, and aluminum arc welding is being considered as a joining method. Although it is important to understand the fatigue strength of the weld joint in fatigue strength design, there is no CAE model for arc welding that joins the casting base metal and plate base metal. In this study, a new model using a multi-point constraint function was developed, and it is shown that fatigue strength evaluation is now possible.

A Study on Improving Correlation between Analysis and Test Results for Vibration Fatigue Durability and Computational Fluid Dynamics

GeonHee Cheon･NamJin Kim･JinKyu Song･WonSeok Choi･JungSub Kim (Seojin Industrial)･GyuHo Shim (Eco-Plastic)

The purpose of CAE analysis is to anticipate the performance of vehicle components in advance of making the prototype. It is an important tool for effectively cutting the costs and time during the product development process. Thus, maintaining the accuracy of analysis results is critical and further study is necessary to improve the correlation with test outcomes. Consequently, this paper aimed to describe the correlation between analysis and test outcomes during the battery case and chassis frame development process under three topics including : vibration fatigue durability, pressure drop and electrodeposition coating (E-Coat).

A Study on the Development of High Strength Rear Trailing Arm for Electric Vehicles

HeeSang Gong･JinKyu Song･JinSung Kim･MoonSub Song･HoSang Park･DongHoon Kim (Seojin Industrial)

Due to global environmental regulations, the automotive industry is focusing on developing electric vehicles to reduce greenhouse gas emissions. The main parts of an electric vehicle is a battery pack, and the weight of the car is gradually increasing due to the increase in battery capacity. As the weight of the vehicle increases, the development of high strength chassis parts is required. This paper describes the process of developing a high strength rear trailing arm for EV vehicles. The main topics include formability verification for high strength steel and performance verification through test and CAE Analysis.

Development of Accuracy Improvement Technology for Surrogate Models using Shape Generation AI

Hiroaki Onodera･Noriko Ohtsuka･Mashio Taniguchi･Masatake Kimura (Toyota Motor)

To improve the performance prediction accuracy of surrogate models for exterior panels, a cycle that explores and detect a lack of training data in design space, creates new training data using 3D shape generation AI and CAE for the detected area and iteratively update the surrogate model is established. The process was applied to the surrogate model of hood outer rigidity performance and the prediction accuracy is improved.

Study of Surrogate Model Construction for Evaluation of Crash Box Performance

Yoshitaka Wada (Kindai University)･Asuka Endoh (Marelli)･Yuki Okumoto (Mazda)･Kai Morimoto (DENSO)･Takasue Kikuchi (DAIHATSU MOTOR)

Expectations for the construction of surrogate models of physical problems using machine learning have been growing year by year. Understanding how to use and build surrogate models is an essential key to their practical application. In this study, we attempted to construct a surrogate model to predict the maximum reaction force and energy absorption for a rectangular cylinder shape that resembles a crash box. The machine learning methods used were neural networks and decision trees to construct the predictor. Since the introduction of parameters that represent the phenomenon in a more linear form is necessary to improve accuracy, input data design was conducted. An analysis of data in which the improvement of accuracy is hampered by differences in buckling modes is also reported. In this presentation, the results obtained through the activities of the AI-ML Technology Application WG in the Structural Strength Section Committee will be presented.

Study on the Body Torsional Rigidity of Personal Mobility Vehicles (PMVs) with Active Tilting Mechanisms

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

From the perspective of vehicle dynamics, there is little research on the body torsional rigidity of PMVs with active tilting mechanisms. In this paper, we used a body torsional load balance model and conducted a comparative analysis with four-wheeled vehicles to examine the necessity of body torsional rigidity under various conditions. Additionally, we investigated the impact of body torsional rigidity on obstacle avoidance ability using a dynamic model, validating the effectiveness of this balance model.

Development of Low-cost Bipolar Plates for New Structure Fuel Cell Stack

Kazuo Nunokawa･Kentaro Ishida･Hiroshi Shinkai･Shuhei Goto (Honda R&D)･Satoshi Oyama (Honda Motor)

The bipolar plate in this study have been coated before pressing to achieve cost reduction without compromising durability. The seal structure has been changed from rubber seal structure to metal bead seal structure formed by pressing and weld structure.New fuel cell stack achieved one-third in production costs and twice the durability compared to the conventional fuel cell stack.

Development of UEA with Both Durability and Cost Performance for New Structure Fuel Cell Stack

Takashi Kato･Akira Nakahara･Takuya Ohkura･Masakuni Yamamoto･Satoru Terada･Akihiro Noda (Honda R&D)･Nagayuki Kanaoka (American Honda Motor)

In the UEA of the newly structured fuel cell stack installed in HONDA's CRV-FuelCell, we worked to build a deterioration model for each component and improve its accuracy, and reflected the material specification limit range in operation control. As a result, we have achieved both lower cost and improved durability for MEA for CLARITY FUEL CELL.

Lifetime Assessment of Fuel Cell Output Control on Fuel Cell Hybrid Test Train

Takashi Yoneyama (Railway Technical Research Institute)･Minhao Wen･Yida Bao･Sihai Xu･Wei-Hsiang Yang･Yushi Kamiya (Waseda University)･Kenichi Ogawa･Manato Kaneko (Railway Technical Research Institute)

To assess the impact of fuel cell output control methods on the lifetime of a fuel cell in the fuel cell hybrid test train, we developed a predictive model for the fuel cell output voltage degradation. We utilized the predictive model to evaluate the differences in fuel cell output control methods that affect the lifetime of the fuel cell using a drivng energy simulator.

Development of Model-based Humidity Control using Humidifier Model in Fuel Cell Systems

Shuto Maniwa･Yohei Hidaka･Koichi Kimura･Nobuki Koiwa (Honda R&D)

To improve fuel cell durability, proper control of membrane water content is crucial. A one-dimensional model replicating the porous hollow fiber membrane humidifier's internal phenomena was constructed to estimate humidification. Using this model, a model-based control method for water content during operation was developed.

Sensitivity Analysis on Charging Condition and Operating SOC Range to Degradation of LFP-type lithium-ion Battery

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

A sensitivity analysis was conducted on the effect of charging condition and operating SOC range to degradation of LFP-type lithium-ion battery as a basic study for field research planed in near future. The battery degradation was evaluated from two perspective: SOH (state of health) and SOS (state of safety). Repeated charge-discharge in a combination condition of a low temperature, fast charging and operating high SOC area, caused a rapid decline in battery capacity and an increased risk of thermal runaway. Chemical analysis for disassemble cells was also conducted to investigate the cause of the increased risk of thermal runaway.

Charge-Discharge Behavior and Safety Evaluation of Pouch-type Lithium-ion Battery using Laminated Steel Sheets for Cell Case

Misaki Masatsugu･Shintaro Yamanaka･Takehiro Takahashi･Yasuto Goto (Nippon Steel)

We have investigated the use of laminated steel sheets for cell case to improve the impact resistance of pouch-type lithium-ion battery. In this study, a pouch-type Lithium-ion battery using laminated steel sheets for cell case was made and its charge-discharge behavior and safety by crushing test using a round bar was evaluated, which showed good results.

Study of Optimal Thermal Management System for Battery based on Vehicle System 1D Simulation Model (Second Report)

Yuya Hato･Poyuan Liu･Wei-Hsiang Yang･Toshio Hirota･Yushi Kamiya (Waseda University)･Kiyotaka Sato (Mazda)

Thermal management for the lithium-ion battery in the electric vehicle, which controls the battery temperature, is important to counteract power output and degradation of the battery. To design an optimal thermal management system, it is effective to use a vehicle system 1D simulation model. In the first report, we proposed optimal thermal management system for BEVs. In this report, we tested the system's cooling and fast-charging performance, which are issues for BEVs using the vehicle system 1D simulation model.

Evaluation of Thermal Runaway Propagation of Prismatic Lithium Ion Battery, whose Cell Case Was Made by Steel

Kosuke Kawamoto･Yasuto Goto (Nippon Steel)･Tatsuo Nagata (Nippon Steel Technology)

Aluminum is the main material of cell case of prismatic lithium-ion battery, but using nickel electroplating steel sheets is expected to improve safety, increase volumetric energy density, reduce costs, and so on. In this study, a prismatic lithium-ion battery using a nickel electroplating steel plate as a cell case was fabricated, and when thermal runaway propagation was evaluated, it was confirmed that thermal runaway time was extended.

Proposal of Concept Shape for Drastic Improvement of Aerodynamic Performance of Heavy-duty Vehicles
-Optimization of Overall Vehicle Shape-

Daisuke Kawano･Soma Iiboshi･Takayuki Ogawa (Osaka Sangyo University)

Because the air drag of a vehicle is proportional to the square of the vehicle speed, the vehicle shape of a long-distance transport truck especially has a significant impact on its fuel efficiency. In this study, the overall vehicle shape, including the cab and luggage compartment, was optimized using a multi-objective optimization method. As a result, it was found that the optimized concept shape significantly reduced air drag while ensuring driving stability.

Aerodynamics Development of Sit-ski for Beijing 2022 Paralympics

Ayaka Iwawaki･Kazuki Funahashi･Tatsuya Mita･Yuko Kobayashi (Toyota Motor)

A sit-skiing event in an alpine skiing is a high-speed downhill competition, so time reduction is achieved through reduced aerodynamics drag.
In order to reduce aerodynamics drag of sit-ski, an analysis of the aerodynamic forces acting on conventional sit-ski, proposals for shapes aimed at reducing aerodynamics drag, and verification of the effectiveness of the proposed shapes were conducted. Therefore, the results are reported.

Study of Aerodynamic Performance Surrogate Modelling for Minivan Vehicles

Hiroshi Tanaka･Yuya Ishiguro･Keiko Amano (Toyota Systems)･Tatsuya Komamura (Toyota Auto Body)

In recent years, the need to improve fuel economy has led to increased demands for aerodynamic performance (reduction of air resistance). Minivans tend to prioritize securing interior space in response to customer needs, which often conflicts with aerodynamic performance. This study reports on the construction of a surrogate model for small to large minivans with the aim of synchronizing design development and aerodynamic performance development in the vehicle development planning stage and predicting aerodynamic performance in a short time.

Numerical Study of the Parameters used in Boiling Heat Transfer Prediction Models under Low Pressure Subcooled Boiling

Yoshiki Tanaka･Takaya Sato･Takeshi Ooyama (DENSO TECHNO)･Yukinori Hamaji･Masayuki Tokitani (National Institute of Fusion Science)･Yoshiyuki Tsuji (Nagoya University)

Most of the boiling models used in the commercial analysis are based on experimental results under high pressure conditions. Thus, we consider that these prediction models have some issue when it used under the low pressure conditions equivalent to the automotive equipment. So we conducted the numerical boiling simulation and compared with the experimental results. And we examined the effect of the boiling parameters.

Numerical Analysis of Under-expanded Jets for Gas Fuel Injection using OpenFOAM

Makoto Nagaoka･Daiki Shindo･Hiroki Sowa･Kanta Takiguchi (Osaka Sangyo University)

The calculation accuracy of the open CFD software OpenFOAM was validated as a tool for analysing gas jet characteristics for further effective use of gas fuels. The under-expanded jets formed when hydrogen, methane and nitrogen are injected into the atmosphere from a gas fuel injector were compared with visualisation experiments using the Schlieren method. The differences between calculation methods such as flux difference scheme and turbulence models, and jet characteristics depending on gas type were analysed.

Development of a Technology for Predicting Exhaust Airflow Noise during Engine Combustion using a Hybrid Method

Toru Tsurumoto･Kyoji Ishihara･Toshiyuki Hirobe･Osamu Torobu (Mazda)･Naoki Nakamura･Takahiro Shinkawa (HIROTEC)

Due to the recent strengthening of noise regulations, vehicles with internal combustion engines are required to reduce exhaust noise. To improve development efficiency, we have developed a technology that quantitatively predicts the frequency characteristics of airflow noise, which is one of the components of exhaust noise caused by engine combustion and exhaust gas flow, using a hybrid method that combines CFD (Computational Fluid Dynamics) and acoustic analysis.

Development of Prediction Method of Parts Temperature in Idling State and Factor Analysis of Temperature Rise from Heat Source

Yuki Morita･Koichi Ishikawa･Hiroyuki Takamura (Mitsubishi Motors)･Reon Wachi (Mitsubishi Automotive Engineering)･Zongguang Wang (Mitsubishi Motors)

While a vehicle idling, the temperature of vehicle parts rises due to the reduction of travel wind. The idling state is transient because of the temperature drop of exhaust pipe and has complex flow field because of cooling-fan operation. This causes difficult prediction of the maximum temperature of parts in idling state. Thus, the coupled CFD simulation method is developed to predict the maximum temperature of the parts in idling state.
In addition, the method is developed to analyze the factor of temperature rise from exhaust pipe in order to put heat protector to reduce heat damage effectively.

Scalable Simulation of Multiple Pedestrian and Drivers based on Behavior Models

Yuki Ban･Toru Watanabe･Hiroyuki Okuda･Tatsuya Suzuki (Nagoya University)･Takuma Yamaguchi･Chieko Nishizawa･Kazunori Ban (Toyota Technical Development)

Verification of automated driving systems requires reproduction of a wide variety of traffic conditions. The traditional model needs to be relearned based on the number of traffic participants. In this study, we will use proximity between traffic participants to build and simulate scalable pedestrian and driver behavior models.

Analysis of Decision-making of Pedestrians0' Crossing Behavior for Incoming Car Fleet

Takashi Nishimoto･Hiroyuki Okuda･Tatsuya Suzuki (Nagoya University)･Chieko Nishizawa･Takuma Yamaguchi･Kazunori Ban (Toyota Technical Development)

Understanding the behavior of pedestrians, who are vulnerable road users, plays an important role in the development of intelligent vehicles. In this study, we focus on decision-making of pedestrians' crossing behavior when a line of vehicles approaches the pedestrians at unsignalized crosswalk. We report the results of observing pedestrians' behavior using a virtual environment and analyzing their decision-making of the crossing behavior.

Impact of Communication Delay on Passing Walk Behavior in a Pedestrian Simulator

Takuma Yamaguchi (Toyota Technical Development)･Hiroyuki Okuda･Tatsuya Suzuki (Nagoya University)･Eisuke Kobayashi･Kazunori Ban (Toyota Technical Development)

Remote simulations always cause communication delays, which delay the transfer of information to each other. These communication delays are an important requirement in simulator design because they have a significant impact on human interactive behavior. Therefore, we validate and evaluate the data using two simulators that can communicate with each other.

Trust Estimation of Pedestrians in Vehicles Approaching a Pedestrian Crossing in a Real Environment

Chisato Moriyama･Takuya Hamamoto･Da Li (Fukuoka University)･Toshihiro Hiraoka (JARI)･Shintaro Ono (Fukuoka University)

In this study, we conducted a confidence estimation experiment for pedestrians crossing in a real environment. Pedestrian and vehicle behaviors were captured by ground and in-vehicle cameras, and confidence was estimated by deep learning based on the distance between them and the pedestrian's skeletal coordinates. The overall correctness rates before and during crossing were 77% and 64%, respectively, revealing a trend in pedestrian behavior.

Proposal of a Simulation Model Considering Engine Block Mating Surfaces

Natsuki Takahashi･Masato Mikami (Yamaguchi University)

Existing research on combustion-induced vibrations uses Wavelet cross-correlation analysis to determine the transmission delay of combustion-induced vibrations in the single-cylinder diesel engine, and investigates the transmission path. In this study, we improved the simulation software that simulates an actual engine, and investigated from a structural perspective a method to bring the vibration acceleration on the outer wall of the engine closer to the experimental value.

Enhancement of Two-motor Hybrid Engine Start-up Vibration Performance by Motor Starting Torque Control Considering Power Plant Resonance

Satoshi Watanabe (Honda Motor)･Koichi Tahara･Tomohiro Kitayama (Auto Technic Japan)

Two-motor hybrid engine starting vibration has large level differences depending on the crankshaft starting angle. This study focuses on the power plant rigid-body resonance, and reduces the power plant vibration peak at different crankshaft-start angles, which is formed when the engine speed rise period and the power plant rigid-body resonance match, by changing the engine speed rise period to improve the starting vibration performance.

Improvement of NVH Performance and AWD Performance by Applying a Torsional Damper to 4-wheel Drive Vehicles with CVT

Hiroyuki Fukudome･Satoshi Yamashita･Jun Fujita･Tomohiko Tezuka (Honda Motor)

This paper presents a combined vehicle testing and CAE modelling approach to apply the torsional damper in AWD vehicle equipped with CVT. By applying it in the optimal position of propeller shaft, NVH performance related to the torsional resonance in the drivetrain system was improved without worsening the vibration caused by rotational imbalance. Furthermore, this approach provided greater flexibility in rear drive force settings, which improved AWD performance too.

Establishment of Factors Analysis for Equipment Differences in Sound and Vibration Measurement in the Transmission Unit and Determination Method of Appropriate Jig Specifications

Toshiki Nagamine･Takuya Kusakabe･Hiroshi Sho･Toshio Fuwa･Kazuki Takase (Toyota Motor)

When introducing evaluation equipment to measure noise and vibration in transmission units, we encountered an issue with obtaining different results compared to other equipment. To address this, we modified the installation fixture specifications for the transmission unit.
We created a realistic equipment model based on actual measurements and performed a factor analysis in collaboration with the unit. This analysis allowed us to determine the fixture specifications in advance.

A Planetary Gear Noise Analysis based on the R-S Coupling Principle

Masatoshi Kanno･Hiroyuki Shintani･Masanori Ogawa (Estech)

As the smallsized and high-speed transaxles prevail, demands for the accurate prediction technology of the planetary gear noise are increasing.The R-S coupling principle considers the gear rotation in the frequency domain and can predict the sideband vibration.This report extends the subject of the R-S coupling principle from parallel 3-shaft e-Axles to devices with planetary gears, and reports its usefulness.

Gear Structure Optimization of Diesel Engines using Generative Design

Seiya Yamagishi･Kazuya Okazaki･Yasuhiro Ishikawa･Kennichi Yamashita (Isuzu Advanced Engineering Center)

Generative design was applied to commercial diesel engines to reduce weight significantly. A gear train model that can take account of three-dimensional elastic deformation was used to investigate adverse effects due to reduced stiffness. The geometry study was conducted to minimize the effect of the stiffness reduction on the deterioration of the meshing. The effect of friction reduction by replacing conventional items was confirmed by actual equipment experiments.

Tire Pass by Noise Prediction Model with Tire Structure Data and Pattern Image

Yonghun Kim･Jonghun Seo･Kibum Kim (Hankook Tire and Technology)

As environmental regulations have been tightened recently, each automotive and tire companies are actively researching and developing to satisfy regulations. Among these, tire noise during driving noise in vehicles is becoming important due to the increase in contributions due to the change of evaluation method and the increase in vehicles using electric motors. This change requires high accuracy for the tire noise prediction model, which is basic to the design of the product. In this paper, we conducted a study on the complex artificial intelligence/machine learning modeling approach considering the tire -related tire parameters to the pattern image of the tire.

Prediction of Tire Pattern Noise Considering Road Surface Roughness

Takahito Sakuma･Ryota Tamada･Masaki Shiraishi (Sumitomo Rubber Industries)

There is a significant difference in tire pattern noise between rough surface roads such as ISO-compliant roads and smooth surface roads. While the prediction of pattern noise using CAE is generally carried out on smooth surface roads, there is a difference in exterior noise measurement tests that are usually conducted on rough surface roads. Therefore, we conducted a study on the prediction of pattern noise on rough surface roads using CAE.

Simple Method for Estimating Tire/Road Noise under Acceleration Torque based on Tread Block Rigidity

Satoshi Atobe (Nihon Michelin Tire)･Takashi Kondo (Toyota Motor)･Yoshinori Saito (Nihon Michelin Tire)･Masashi Komada (Toyota Motor)

This study proposes a simple method for estimating increase of tire/road noise due to acceleration torque from the rigidity of tread block. FEA or an analytical model based on mechanics of materials is utilized for the calculation of tread block rigidity. Tire-rolling noise is measured by indoor tire-alone drum tests, and increase of noise due to acceleration torque is determined. The validity of the proposed method is examined for tires with different tread block rigidity which were prototyped by adopting different tread compound.

Development of Suspension for Reducing Road Noise using Multi-objective Optimization Method with FRF Based Substructuring

Masaki Kobori･Hirotaka Shiozaki･Hiroki Aoyama･Yuki Sugiura (Mitsubishi Motors)

With the spread of electric vehicles, the engine noise is decreasing, and the importance of reducing road noise, which is making a relatively large contribution, is increasing .In this research, We developed multi-objective optimization method using FRF Based Substructuring to develop suspension strucure that reduces road noise while simultaneously achieving tradeoffs such as handling stability and weight.

Experimental Identification of Tire Modes Contributing to Dynamic Axle Load

Hironori Yamada･Keisuke Abe･Naoto Sato･Jun Tanaka (SUBARU)

A tire measurement technique was developed to determine spindle force in rolling and non-rolling, grounded and ungrounded conditions. Using the data obtained, tire modes that contribute significantly to road noise were extracted, and changes in tire characteristics due to rolling and ground contact were analyzed.

Tire/Road Noise Modeling with Considering Acceleration for Exterior Noise Prediction

Ayumu Yanagibayashi･Yoshihiro Shirahashi･Kai Kurihara (Kanagawa University)･Masayuki Wada (Nissan Motor)･Toru Yamazaki (Kanagawa University)

In recent years, the penetration rate of EV has been increasing, and the contribution of tire/road noise to vehicle noise has been increasing.Therefore, the cause of tire torque noise, which is the noise caused by the effect of tire torque during acceleration, was considered, and a source model was constructed using the dimensions of the tread blocks.The influence of tire torque noise to road traffic noise was also clarified.

Sound Quality Evaluation Difference to Vehicle Interior Noise between Automatic and Manual Driving Condition

Yudai Irie･Nawoki Okabayashi･Junji Yoshida (Osaka Institute of Technology)

In near future, autonomous vehicles are expected to be more popular due to the technology development. This transition from active to passive driving condition may change the drivers’ impression to vehicle interior sound. In this study, we investigated whether drivers’ impression to interior sound change or not according to the condition through subjective evaluation test using a driving simulator. As the result, interior sounds were found to be evaluated as more discomfort at passive condition than that at active condition.

Feature Extraction of Car Driving Sound using Neural Network with Acoustic Multi-parameters

Yota Oshima･Kai Aso･Soichiro Tanabe･Takeshi Toi (Chuo University)

Time-frequency analysis, correlation between carrier frequency and modulation frequency, and multiple psychoacoustic metrics are defined as acoustic multi-parameters, and a neural network that simultaneously inputs these parameters is used to classify car driving sounds. The data classification contribution of each parameter and the characteristics of the sound for that parameter are extracted by visualizing the data classification basis of the neural network.

Study of Engine Operating Point Optimization Incorporating Human Cognitive Processing (2nd Report)
-Comparison of Cognitive Processing Characteristics for Engine Noise during Driving between Japan and U.S.-

Shimpei Nagae･Takaaki Yamanaka･Toshio Enomoto (Nissan Motor)

The authors showed that the evaluation of the engine noise of e-POWER varies depending on various cognitive influences during driving, and utilized for optimization of the operating point. In this report, we developed a virtual e-POWER engine noise environment that can be installed in BEVs, and collected and compared engine noise evaluation data during driving in Japan and U.S. to investigate whether there are any differences in such changes by country.

Development of Automatic Evaluation System for BSR

Kazutaka Yonemori･Shoki Tsuchibuchi･Takaaki Yamanaka･Yoshinari Tokunaga･Yohei Kurami･Takayuki Kume (Nissan Motor)

In our company, the load cycle testing to reproduce and evaluate BSR (buzz, squeak, and rattle) comes to be long our testing. It is a hard for evaluators to confirm BSR throughout the entire duration of the testing. In this report, we developed the automatic evaluation system to achieve BSR detection throughout the entire duration of the testing.

Rear Wheel Steering System with Target Characteristic of Vehicle Slip Angle

Shogi Fukukawa･Yoshiaki Tsuchiya (AISIN)･Yoshitaka Fujita (Toyota Motor)･Takuya Yamamoto (AISIN)

It is known that during low-speed maneuvers, the vehicle body tends to turn outward relative to the direction of travel.
We believed that bringing the vehicle body closer to the direction of travel would reduce the amount of eye movement for the driver and improve safety.
In this study, we evaluated the head and eye movements of drivers using driving simulators and actual vehicles, and found that there is an optimal value for the deviation between the vehicle body and the direction of travel depending on the vehicle speed.

The Influence of Vertical Suspension Friction on Planar Vehicle Dynamics

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

The effect of suspension vertical friction on vehicle planar motion was analyzed. This friction affects roll dynamics, influencing planar motion through roll steer mechanism. A new method is proposed to evaluate suspension friction's effects on vehicle behavior, resembling driver assessments under slow ramp steering conditions. which is neither a conventional steady state nor a transient response test.

Analysis of Coupled Roll and Plane Motion

Eiji Matsuura･Hideki Sakai (Kindai University)

One of the most important aspects of automobile performance evaluation is maneuverability. Since maneuverability greatly affects whether or not the car moves as the driver expects, it is an important performance in the development of a car.This study analyzed the effect of changes in the forward and backward tilt of the roll axis on roll motion.When the roll axis is tilted forward, the vehicle speed region of the roll motion around the roll axis is extended.

Quantitative Evaluation of Roll Feeling

Yuji Yoshioka･Kei Sakamoto･Jun Nakahara (Honda Motor)

A method to evaluate subjective characteristics quantitatively was investigated that is difficult to observe as physical quantities. The influence of road roughness and sensor resolution were reduced by using a driving simulator. Then, the correlation between vehicle behavior and subjective characteristics was examined by changing the vehicle behavior. As a result, it was possible to quantitatively evaluate the contribution of the phase difference between the roll and pitch angles to the feeling in turn.

Enhancement of Feeling in Turn by Control of Pitching Behavior

Naoto Ohkubo･Takashi Yanagi (Honda Moter)

In order to provide a natural feeling in turn for general drivers in daily driving, the relationship between roll behavior, pitch behavior, and turning feeling during maneuvering was studied, and a method was examined for adjusting the pitching behavior produced by control of acceleration and deceleration. Driving simulator test showed that the method is effective in enhancing the feeling in turn.

Consideration on Modeling of Chassis Torsional Stiffness around Roll Axis and Analytical Parameter based on Vehicle Dynamics

Ikkei Kobayashi･Fumiya Yoshida･Liting Fu･Yusuke Ebashi･Hayato Yamada･Jumpei Kuroda (Tokai University)･Taro Kato (Tokyo University of Technology)･Ayato Endo (Fukuoka Institute of Technology)･Hideaki Kato･Takayoshi Narita (Tokai University)

Understanding the contribution of chassis torsional stiffness to vehicle dynamics is important for automobiles, which aim to control vehicle dynamics characteristics by suspension stiffness. In this study, a vehicle dynamics model that separates the rigid body of the sprung mass and includes analytical parameters for chassis torsional stiffness is investigated and its effect on lateral dynamics is reported.

Effect of Tire Tread Profile on Cornering Characteristics

Takayuki Toyoshima (Honda Racing)･Eisei Higuchi (Honda R&D)･Toshiaki Matsuzawa･Takeshi Hotaka･Tomonori Sakai (Honda Motor)

The presentation will discuss research into a new method for predicting the effects of changes in tire profile and tread rubber specifications on individual tire cornering characteristics (especially cornering stiffness) with greater accuracy than conventional methods, and the results obtained from this research.

Slip Control of Two-Input Two-Output Torque Vectoring System for Electric Vehicle Considering Turning Trajectory

Ryota Takahashi･Kaoru Sawase･Naoki Takahashi (Mitsubishi Motors)･Hiroyuki Fuse･Hiroshi Fujimoto (The University of Tokyo)

Combine traction performance of like a mechanical defrock and turning performance by the traction and turning trajectory can be controlled slip of the right and left wheels in the sum and difference mode for Two-Input Two-Output Torque Vectoring System for electric vehicles.

Improving Roll Dynamics by Focusing on the Response Difference between Electric Drive Units and Friction Braking Units

Hiromitsu Toyota (The University of Tokyo/MITSUBISHI MOTORS)･Binh-Minh Nguyen･Sakahisa Nagai･Hiroshi Fujimoto (The University of Tokyo)･Kaoru Sawase (Mitsubishi Motors)

In case of prioritizing the performance of planar 3 degrees of freedom motion by driving and braking force control, the roll behavior sometime may worsen depending on the control method.
　Therefore, in this paper, we focus on the response difference between electric drive units and friction braking units, proposing a control method that optimally controls only the driving and braking force of all four wheels to improve roll behavior without deteriorating the performance of planar 3-degree-of-freedom dynamics.

Internal Torque of AWD with Propeller Shaft and its Effect on Vehicle Dynamics

Shinya Konishi (Toyota Motor)

The effect of propeller shaft AWD on vehicle attitude is analysed with a focus on pitch motion. This paper reports the results of the analysis focusing on the internal torque caused by the pitch motion and the vehicle attitude change produced by the change in suspension geometry.

Dynamic Performance Evaluation of a Personal Mobility Vehicle (PMV) with an Inward Tilt Mechanism on Uneven Roads

Tetsuya Kaneko･Junlang Zhou･Shohei Kitazawa (Osaka Sangyo University)･Tetsunori Haraguchi･Ichiro Kageyama (Nihon University)

In this study, we verify the dynamic motion capabilities of the Personal Mobility Vehicle (PMV), which inclines inward during turning. The PMV maintains its upright posture not only during driving on straight roads, slanted roads, and crossing obstacles but also during driving on rutted tracks. Previous studies have examined the static design requirements for this purpose. In this paper, we conduct verification through simulations using a detailed kinematic model of these dynamic motion capabilities.

Analysis of Statistical Data on Single-vehicle Accidents Caused by Pedal Misapplications

Yoko Kato･Yasuhiro Matsui･Akihiro Abe･Michiaki Sekine (NALTEC)

Our previous report revealed that pedal misapplication accidents involving pedestrians tend to result in severe injuries to the pedestrians. On one hand, the drivers involved in single-vehicle accidents also would have severe injuries. In this report, we analyzed statistical data on single-vehicle accidents caused by pedal misapplications.

The Effects of Visual Field Training on Driving Performance of Elderly Drivers
-Study on Driver Characteristics for Delaying Driving Cessation (43)-

Akio Hirano･Kunitomo Aoki (Nagoya University)･Kazuhiko Yamashita･Hidenori Horita･Kazumasa Onda (Suzuki Motor)･Sueharu Nagiri (Nagoya University)･Makoto Inagami (Gunma University)･Hiroshi Kishi･Takashi Yonekawa･Hirofumi Aoki (Nagoya University)

We examined the effects of visual field training on driving performance in elderly drivers. Participants drove in an immersive driving simulator (DS) with a dynamic useful field of view (UFOV) task.　After the DS driving test, the intervention group received visual field training with a tablet device twice daily for a week, while a control group did not receive any training. Then, another DS driving test was conducted and the intervention group showed significant improvement in some driving metrices.

Evaluation of Driving Ability in Elderly Drivers through Dynamic Grip Strength Analysis

Ryuma Majikina･Yasumi Ito･Ryuichi Yamada･Ryosei Naito･Qin Xu･Takashi Nonaka･Ayumu Honda･Yoshiyuki Kagiyama (University of Yamanashi)･Yuki Tanaka (Gunma University)･Tetsuya Nemoto (University of Yamanashi)

This study aims to elucidate the relationship between driving ability and various aspects of muscle strength involved in accelerator and brake operations, as well as steering control. Based on the results of dynamic grip strength measurements, we assess factors such as the time required to exert muscle strength, the rate of muscle strength increase, maximum muscle strength, and muscle strength endurance.

Driver Evaluation System based on Head Movement Data: Feedback Effect for Changing Driving Behavior of the Elderly Driver

Yuki Yoshihara (Nagoya University)･Hiroko Tanabe (Hokkaido University)･Nihan Karatas･Hitoshi Kanamori･Asuka Harada (Nagoya University)･Motoshi Kojima･Shuhei Manabe (Toyota Motor)･Takahiro Tanaka (Nagoya University)

To prevent elderly drivers crashes at stop sign intersections, we present a driver evaluation system that can visualize driver head movement as well as its safety levels as driving score. The system based on a driving simulator and a driver monitoring system, and generates a diagnostic report from driving data. We validated the efficacy of the feedback by giving the report to eight elderly drivers.

Examination of the Effect of Age-related Changes in Body Schema on Pedal Operation

Takashi Hosokawa･Takashi Tagawa (JARI)･Machiko Hiramatsu･Hiroyuki Mae (JAMA)

This study examined the root cause of pedal missteps, in which the driver presses the accelerator pedal while thinking it is the brake, based on the hypothesis that age-related distortion of the body schema affects the pedal misstep. We developed an evaluation method for the sense of operation, which is a component of body schema, and conducted experiments. Multiple regression analysis using foot position error during pedal change as the objective variable yielded a significant model with leg position sensitivity and plantar sensation as explanatory variables, indicating that blunted sensation of operation may influence the occurrence of pedal operation errors.

Age-related Changes in Pedal Operation and Their Effects on Driving (3rd Report)
-How to Make Pedals Easier to Operate for Elderly Drivers-

Machiko Hiramatsu･Tsutomu Kawano･Yui Kato･Akihiko Ebina･Tsuyoshi Sakuma (Nissan Motor)

Pedal operation is a driving task in which future vehicles could better account for physical characteristics of elderly drivers. We previously reported that the dexterity for small pedal operations during slow maneuvers decreases with age, and that this affects behavior such as passing through intersections with a stop-sign and parking. In this paper, we describe the muscular effort of the legs when operating pedals with different geometries and counterforces and our conclusion for characteristics of pedals that are easy for elderly people to operate.

Examining the Effectiveness of Cross-Modal for Guidance in Automobile Driving

Miyu Kamota (Sophia University)･Takashi Otomo･Hideki Sakamoto (Alps Alpine)･Shoichiro Takehara (Sophia University)

The purpose of this study is to examine the effect of cross-modality, the interaction of the senses, in order to realize intuitive and comfortable guidance. In order to confirm the effectiveness of cross-modality, we extracted evaluation factors by conducting an evaluation grid method experiment. In this experiment, Subjects compare and evaluate guidance with different sound/vibration combinations within specific visual situations.

Structure of Model to Quantify Psychological Aspects of Tactile Feedback of Switches (First Report)

Takashi Otomo (Alps Alpine)･Miyu Kamota (Sophia University)･Hideki Sakamoto (Alps Alpine)･Shoichiro Takehara (Sophia University)

Switches equipped in the cockpit of automobiles require various tactile feedbacks depending on their purposes. Evaluation of tactile feedback has been conducted using adjectives. However, questions arose from the analysis results because of including psychological adjectives such as “comfortable”. In this study, we employed an evaluation grid method to structure and analyze Kansei. As a result, we constructed a model to quantify the psychological aspects of the tactile feedback of switches.

Development of Sensory Evaluation Methods and Verification using the Large Driving Simulator for Driving Pleasure

Takumi Aoki･Shoichiro Takehara (Sophia University)･Katsunori Tanaka･Hiromi Fujita･Koichi Onishi (Nissan Motor)

In this study, we conducted a sensory evaluation of the pleasure of driving a car. First, we classified the experiment participants based on the results of an SD method questionnaire conducted during real vehicle experiments and identified the characteristics of driving pleasure from the differences in preferences among each group. Furthermore, using the large driving simulator, we proposed an experimental method to verify these characteristic differences and demonstrated its effectiveness.

KANSEI-indexing for Creating Experiential Value in Moving Spaces

Aya Sakuma･Hirotoshi Nozaki･Yu Yamamoto･Yoshiko Ohzu (Sumika Chemical Analysis Service)

Achievement of human well-being is one of the important things in the value of next-generation mobility. Improving the quality of time spent on the move is effective to achieve it.
In this study, we aim to advance spatial design by identifying the values people seek in moving spaces and the factors contributing to these values. Using KANSEI engineering, we index the connection between these values and contributing factors.

Estimation of Passenger Anxiety State using Physiological Indexes under Real Vehicle Conditions

Yuta Aoki (Honda Motor)･Tomohiro Imai･Masamitsu Shiono (Honda R&D)

In this study, we consider that one of the causes of traffic accidents is human error linked to the mental state of the passenger, and we conducted basic technological research on estimating this mental state in order to prevent accidents. Specifically, we propose a machine-learning model that estimates the state of anxiety by inducing feelings of anxiety in a real car, searching for multiple physiological index changes that are linked to anxiety.

Relationship between Sensory Evaluation and Body Behavior in Braking During Autonomous Driving

Shoichiro Takehara (Sophia University)･Masanori Matsuoka (Advics)

It is necessary to realize safe and comfortable automatic driving functions. This study aims to elucidate the relationship between human sensibility and posture-holding behavior for braking during automatic driving. In this paper, we classify experimental participants by performing cluster analysis on the results of sensory evaluation, and investigate their preference for braking by comparing the tendency of posture-holding behavior and psychological evaluation for each group.

A Study on the Impact of Visual Information on the Comfort Evaluation of Driver's Seat

Ryo Kamae･Manato Furuta (Kyoto Institute of Technology)･Tetsuya Kitagawa･Ryuji Furumai (Fuji Seat)･Yukiko Nishizaki (Kyoto Institute of Technology)

The evaluation of the comfort of driver seats has traditionally been based on information obtained from tactile information. However, humans integrate multiple sensory inputs to make such evaluations. This study aims to investigate how visual information influences comfort assessments. Using virtual reality to visually present different vehicle interiors, it was revealed that the comfort of the same driver seat varies.

Optimization and Validation of Seat Factors for Fatigue Reduction using a Musculoskeletal Simulator

Ryotaro Yoshida･Shinya Okamoto･Hisato Fukuda (Gunma University)･Tsutomu Iwase･Toshihiko Kozai (Gunma University / SUBARU)･Nobuaki Nakazawa (Gunma University)･Masaaki Sakamoto (Takasaki University of Health and Welfare)･Kyohei Uchikata･Hikaru Fushimi･Masami Handa (SUBARU)

The purpose of this paper is to optimize seat factors for the development of a car seat with less fatigue. The musculoskeletal simulator was used to analyze the muscular activity exerted when the important seat factors selected in a previous study were varied, and the optimization of each seat factor was performed under static and dynamic conditions. Sensory evaluation experiments were conducted to validate the analysis results.

Study and Establishment of Method for Evaluating Cabin Air Quality in Large Vehicles
-Measurement of VOCs Emitted from Large Bus Air Conditioning Equipment by Instrumental Analysis-

Kazuhisa Uchiyama (Tokai Technology Center)･Kengo Kii (J-BUS)･Katsuhiro Kan･Takuma Kizu (Isuzu Motors)･Nanae Iwabuchi (ESPEC)･Hidechika Matsui･Hiroshi Niwa (Tokai Technology Center)･Kouichi Tatsu (Isuzu Motors)

The analysis of VOCs in large vehicles, especially large bus air-conditioning systems, has been difficult due to their large size.
In this report, we describe the process of GC-MS analysis of VOCs emitted from a bus air-conditioning equipment using an active sampling method in a large thermostatic chamber.

Basic Study of Visual Communication Technology for Indoor Environments on Public Transportation

Jun Sakaguchi (University of Niigata Prefecture)･Naohide Shinohara (Isuzu Motors)･Kouichi Tatsu (AIST)

This study focuses on visual communication technology using digital signage to display the results of measurements for parameters such as temperature, humidity, suspended particulate matter concentration, carbon dioxide concentration, and illuminance inside public transportation cabins.
Furthermore, a web-based survey and a survey using IoT terminals are conducted to collect public transportation users' declarations about the indoor environment, and the response methods are compared.

Evaluation of Effectiveness of Next-generation Lane Change Assist System for Reducing Driver Burden

Shoei Tomikawa･Saki Shindo (Honda Motor)

In recent years, technology for driving assistance functions has advanced, with features developed to suggest lane changes to drivers in scenarios such as encountering a slow vehicle in front or exiting highways. This presentation will explain the content of lane change assistance proposal functions designed to address unique scenes specific to Japan, which have not traditionally been addressed, and their effectiveness.

Prediction of Merging Vehicle Position using a Rule-based Model based on Machine Learning Insights and Actual Vehicle Validation

Yuta Takashima･Taku Umeda･Tomoki Uno･Yuko Omagari･Kazuo Hitosugi (Mitsubishi Electric)

To achieve safe driving in merging areas, it is necessary for mainline vehicles and merging vehicles to predict their movements and coordinate with each other. In this study, we developed a model to predict the merging positions of vehicles using machine learning and leveraged the insights from this to develop a high-accuracy, low computational cost predictive model based on rule-based methods. Furthermore, we verified its effectiveness through real vehicle tests.

Collision Avoidance Assist for Distracted Drivers using Gentle Deceleration

Takuya Niioka･Yugo Yamaguchi･Yoshihiro Oniwa (Honda Motor)

The number of accidents has decreased these days due to the widespread application of autonomous emergency braking system. For further reductions, however, it is necessary to address the distracted drivers, the primary cause of most accidents, and support them to safely avoid crashes. This paper introduces a method to support collision avoidance by prompting early recognition with gentle vehicle behavior, unlike conventional approaches that involve large braking forces.

LKA, a Lane Departure Prevention and a Haptic Information on Risk

Shoma Edamoto･Shuji Kimura･Tsutomu Tamura･Robert Fuchs (JTEKT)

Lane Departure Prevention (LDP) can reduce the occurrence of traffic accidents by correcting the vehicle heading in the event of a lane departure. We propose the LDP based on admittance control in this presentation. The proposed method can maintain the vehicle in the lane strictly when the driver is hands off while providing haptic information to the driver according to the distance to the lane marking when driver is hands on.

Study on Evaluation of Driving Characteristics of a Remote Pilot of a Vehicle for High Speed Range

Asahi Hiratsuka･Naoki Furugoori･Toshiyuki Sugimachi･Toshiaki Sakurai (Tokyo City University)･Jongseong Gwak (Takushoku University)･Yoshihiro Suda (The University of Tokyo)

With the increasing attention towards mobility services utilizing autonomous driving, there is a growing need to explore remote operation at high speeds. This study replicates the remote driving environment during highway driving using a driving simulator (DS) and evaluates driving characteristics based on DS experimental results. We propose driving assistance systems that take into account the driving characteristics of remote operators and validate their effectiveness through DS experiments.

Stability Improvement of Remote Driving System with Model Predictive Control

Emi Sakaoka･Go Inoue･Rio Suda (Toyota Motor)

This paper shows the negative effect of communication latency on teleoperated vehicle stability and proposes a stabilization method using model predictive control. In this method, the controller can calculate optimal manipulated variables considering communication latency because it has a model of the controlled system with predicted communication latency. This method is validated through testing in the digital twin environment.

Research on Tele-operation Support System that Indicates the Moving Position and Estimates the Amount of Movement by In-vehicle Camera Images

Yuu Miyajima (AIST / Tokyo University of Science)･Shin Kato (AIST)･Makoto Itami (Tokyo University of Science)

Automated vehicles using electromagnetic guide lines, for example, need to travel off the guide lines to avoid fixed obstacles on the roadway. We have proposed a remote control support system that avoids such obstacles not by an autonomous function but by remote control using in-vehicle camera images. In this report, we describe the estimation of the amount of movement using feature points in the vehicle-mounted camera images and the verification of the effectiveness of the system.

Approach Detection of Emergency Vehicles using Siren Sound Processing Considering Ambient Noise in Driving Environments

Ryo Yagyu (AIST / Tokyo University of Science)･Shin Kato (AIST)･Makoto Itami (Tokyo University of Science)

When an autonomous vehicle approaches an emergency vehicle, it is obliged to prioritize the emergency vehicle’s movement and give way. Therefore, there are required to automatically detect the approach of emergency vehicles. This report describes the proposal and evaluation of a detection method that takes into account the noise of the driving environment as a method for detecting the approach of an emergency vehicle using the sound of a siren.

Development of a Map-based Detection Method of Road Markings Degradation by LiDAR-camera Fusion

Akisue Kuramoto (Institute of Science Tokyo)･Ryo Yanase･Keisuke Yoneda･Naoki Suganuma (Kanazawa University)

Proper recognition of road markings' degradation state is important for road maintenance management and the reliability of assistance or autonomous driving systems. This paper proposes a map-based detection method of road marking degradation using quantitative indicators, such as the reflectance and visibility of ​​road markings, obtained by fusing a camera and LiDAR.

Collision Risk-map Robust to Errors in Obstacle's Predicted Trajectory for Trajectory Planning of Autonomous Vehicle

Yuki Kasai･Kazuhiro Sorimachi･Nobuhiro Watanabe･Wataru Yoshiuchi･Nobuhiro Hayashida (Isuzu Advanced Engineering Center)

Trajectory planning based on a risk-map expressing risks caused by obstacles is suitable for urban autonomous driving. This is because the map treats diverse elements in a uniform manner. In a previous work, a risk-mapping method of evaluating spatio-temporal proximity was proposed to express collision risks with moving obstacles. However, this method is susceptible to deviation of the obstacle’s predicted trajectory when applied to actual vehicles. In this study, we apply a binary Bayes filter to the method. Through actual vehicle experiments, we confirmed that our method improves noise robustness and enables trajectory planning that avoids collisions with moving obstacles.

Alignment of Map Coordinate Systems Toward Fusion of Multiple Localization Technologies

Ryoma Kakimi･Taishi Shiotsuki (Toyota Motor)

Fusion of multiple localization technologies and fleet management by control systems are often performed in the areas of autonomous mobility. These technologies often have their own coordinate system, and accurate alignment of these systems is necessary for stable system integration. This paper reports on a technique that uses reference anchor points of each coordinate system to statistically derive the coordinate transformation to enable accurate alignment.

Data-driven Planner for Autonomous Driving Systems Considering Application to Vehicles with Various Specifications

Akira Ito (Aichi Institute of Technology)･Ken Kinjo･Kenta Mukoya･Yuki Asada (DENSO)

A data-driven planner for autonomous driving systems does not work properly for vehicles with different specifications from those used during training, and thus requires re-training for each vehicle.
In this study, we propose a method that combines a data-driven planner and model following control to enable the planner to be applied to vehicles with various specifications without re-training.

Relationship between Mass Burnt Fraction 50% Crank Angle and Low-Frequency Components in Cylinder Pressure

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

A method for estimating the mass burnt fluctuation of 50% crank angle (MBF50%CA) using the amplitude of the fourth-order sin component (b4) include the cylinder pressure has been confirmed. In a typical gasoline engine, the maximum cylinder pressure is between 0 degrees and 45 degrees, and this cycle fluctuation affects b4. The sine wave part of the b4 calculation equation was divided into sections for each node, and the cumulative value was investigated. As a result, the reason for the relationship between b4 and MBF50%CA has been clarified.

Wall Impinging Spray Feature in a DISI Engine under Steady State Cross Flow Fields
-Effects of Cross Flow Velocity and Injection Pressure on Liquid Film Formation-

Tomohiro Ishiguro･Dai Matsuda･Eriko Matsumura･Jiro Senda (Doshisha University)･Shigenori Haraguchi･Yoshihisa Sato (Honda Motor)

Direct Injection SI engines have problems of PM emission and oil dilution. In this study, visualization measurements of wall-impinging sprays were performed under the condition of in-cylinder flow in order to understand the spray formation and liquid film behavior of wall-impinging sprays in a flow field. In this paper, we report the results obtained by changing the cross flow velocity and the injection pressure.

Analysis of Knocking Occurs Under High Speed and High Load Conditions in a Turbocharged Gasoline Engine

Changzhi Zeng･Tatsuya Kuboyama･Yasuo Moriyoshi (Chiba University)

In this study, experimental and numerical analysis of a knocking that occurs at high load and high-speed conditions in a production turbocharged SI gasoline engine was conducted. The effects of the spatial distributions of temperature and fuel concentrations on autoignition in the unburned zone and the magnitude of the following pressure oscillations were investigated.

Effect of Combustion Characteristics on In-cylinder Pressure Oscillation

Tatsuya Kuboyama･Naruki Ezawa･Itsuki Hongo･Yasuo Moriyoshi (Chiba University)

The objective of this study is to clarify the dominant factors of the in-cylinder pressure oscillation in a spark ignition engine. Simultaneous visualization of the in-cylinder flow and flame propagation was conducted using an optically accessible engine to investigate the effect of flame propagation behavior on the heat release rate and the high-frequency components of the in-cylinder pressure oscillations.

Effect of Mixture Distribution on HC Species Formation in SI Engines

Junki Hori･Naoki Yoshioka (Mazda)･Keisuke Yamamoto (Hiroshima University)･Yuya Honda･Michiharu Kawano･Tatsuya Fujikawa (Mazda)･Masahisa Yamakawa･Akira Miyoshi (Hiroshima University)

The use of CN fuel and ZeroEM are essential for future ICE. Catalysts have different purification characteristics depending on the HC species. Low alkanes are particularly difficult to purify and must be reduced by combustion.It is known that lower alkanes remain in higher amounts under rich conditions, but the mechanism of their formation in the cylinder has not been fully understood.In this report, we analyzed the effect of the mixture distribution in the cylinder on the formation of HC species using numerical calculations and the actual engine.

Study on Clarification of Formation Factors of Deposits on Air-fuel Ratio Sensors

Kento Okusa･Kenta Furutani･Kazuho Yoshida･Kotaro Tanaka (Ibaraki University)･Shouta Tobe･Kouta Ishizaka･Tasuku Hasejima･Tetsuo Kitagawa･Masahiro Ono (SUBARU)

Deposits form on the air-fuel ratio sensor used for air-fuel ratio control in direct-injection gasoline spark-ignition engines and affect the signal response of the sensor. In this study, the formation mechanism of deposits on the air-fuel ratio sensor was investigated using an gasoline engine and the factors that affect the response of the air-fuel ratio sensor were clarified.

Material-less calibration using a One-dimensional Engine Model

Isshu Yoshiki･Hiroaki Tone･Akihiro Katsuura･Suguru Fukuda (Honda Motor)

In the development scene of internal combustion engines, there is a demand for shortening the development period and reducing development costs. This paper presents an initiative that enables the proposal of calibration values that meet the selected specifications in a short period of time, by conducting a simulation of the intake air quantity using a one-dimensional engine model, while reducing development costs without using actual machines.

Research of Micro Flow Rate Cooling Control System with Electric Water Pump for Gasoline Engine

Keijiro Koide･Takafumi Murakami･Yutaka Yoshida･Masahiro Suganuma･Naoto Sasaki (Honda Motor)

As the interest in fuel economy and emissions increases, we have defined a flow rate region called "extremely low flow rate" in order to improve engine warm-up performance. In this study, we describe the estimation method of the effect using prediction technology centered on one-dimensional simulation using MBD at the performance design stage, the mechanism of the fuel economy effect due to extremely low flow rate, and the expected additional effects.

Analysis and Model Evaluation of Post-Oxidation Phenomena in Exhaust Manifold of Gasoline Engine

Teruaki Ishikawa･Tatsuya Kuboyama･Yasuo Moriyoshi (Chiba University)

Post-oxidation in the exhaust manifold is known as a method to improve engine performance and reduce emissions. The mechanism of post-oxidation in the exhaust manifold was evaluated by conducting tests on actual engines with different exhaust systems and fuel injection patterns. The post-oxidation phenomena were incorporated into a one-dimensional simulation model to improve the accuracy of the simulation.

A Study on Water Content in Lubricating Oil of Hydrogen-fueled Medium Duty Vehicle on Demonstration

Daisuke Hiyama･Itsuki Motomiya (Tokyo City University)･Ko Onodera (ENEOS)･Takuya Yamaura (Flatfield)･Koji Kikuhara (Waseda University)･Kaname Naganuma (Kanazawa Institute of Technology)･Akemi Ito (Tokyo City University)

A demonstration test was conducted using a heavy-duty vehicle equipped with a hydrogen engine to transport cargo from summer to winter. A sampling survey of the lubricating oil revealed that the amount of water in the oil increased during the winter season. This report describes the results of the study of the relationship between the amount of water in the oil, ambient temperature, oil temperature, and operating conditions, and so on.

A Study on Specifications of Piston Ring for Hydrogen Internal Combustion Engines based on Experimental Investigation and Numerical Calculation

Ryuichi Sasaki･Shinya Koike･Yuusuke Kuga･Keiichi Oshimi･Kazuya Mochizuki･Miyuki Usui (Riken / Riken NPR)･Akemi Ito (Tokyo City University)

In order to clarify influence of piston ring specifications for hydrogen concentration in blow by and oil transport to combustion chamber in hydrogen engine, We evaluate performance of piston ring with experiment results of in house port fuel injection hydrogen engine and numerical calculation results of in house simulation model. From these results, we investigated piston ring specifications suitable for hydrogen engine.

Combustion Characteristics of Blended CH₄-H₂ in Pre-Chamber Engines using Rapid-Compression Expansion Machine Experiments and 3D-CFD Kinetics Simulations

Yixin Feng･Kei Morita･Ryuta Nakao･Ratnak Sok･Jin Kusaka (Waseda University)

A lean burn mixture can improve the thermal efficiency of compressed natural gas. This work investigated the effect of engine wall temperature on the knock combustion of CH4-H2 co-generation systems. A Rapid Compression Expansion Machine (RCEM) was used to study the combustion characteristics of the blended fuel. 3D-CFD combustion simulations were performed using CONVERGE software. Combustion was compared for wall temperatures of 600K, 700K, 800K and 900K. The results showed that knock combustion occurred in all cases, and the knocking intensity increased and occurred earlier as the wall temperature increased.

Simultaneous Structure Design Optimization of Multiple Car Models using FMQA

Toshiki Kondo･Takehisa Kohira (Mazda)･Yuki Minamoto (Fixstars Amplify)

We examine the potential of Quantum Annealing (QA) for efficiently solving large-scale vehicle design optimization problems. In this paper, we focus on FMQA, which is applicable to black-box evaluation functions, and proposes solutions to challenges such as adjustment of function weights and diversity preservation of solutions. By comparing proposed method with conventional optimization methods, we discuss the superiority of QA in actual design problems.

Development of Dynamic Visualization Method of the Load Transfer Analysis Ustar (U^*)

Takehisa Kohira･Sadayoshi Okamoto･Hiromasa Kemmotsu･Masanori Honda (Mazda)

U* analysis has been proposed as a method for estimating load transfer conditions inside a structure. However, when U* analysis is applied to large-scale problems such as car body structures, there are issues with computation time and load path estimation. In this paper, we report on the development of a fast computation method based on parallel computation and a method for estimating load paths in a multi-layered structure such as a car body structure.

Optimizing Driver Seat Comfort using Vehicle Package Factors

Sun Woo Choi (Hyundai Motor)

In order to implement a comfort skin, various cross sections are managed in the drawings, such as a free contour line, a cushion cross section, and a seat back cross section. In particular, FCL is a cross section generated based on a vehicle package and is the most basic cross section for managing the entire seat skin.
In this study, it is considered a method of generating the optimal standard skin based on the seats developed and studied so far. To this end, not only the feedback received from the field after mass production was considered, but also the development history of each seat skin was compared and evaluated.

Optimal Function Allocation Method for ECU to Construct Architecture that Balances Aggregation of Functions and Test Reusability

Takaaki Hayashi･Yuto Imanishi (Hitachi)･Hiroki Maehama･Yoshiyuki Yoshida･Ryosuke Ishida (Hitachi Astemo)

When functions are aggregated to realize centralized ECU, the difference from the conventional function allocation becomes large, and test reusability deteriorates. To balance both of these properties, we propose an optimal method of allocating functions to ECUs that the objective function is set as the weighted sum of the indicators of both of the properties. We also confirmed that the tradeoff between indicators can be visualized by repeatedly executing the allocation while changing the weights of the weighted sum.

A Study on the Development of Optimum Body Structure for Low Entry BEV using 1D Beam Model

Gyuhee Kim･Jung Hun Choi･Ji Hoon Moon･Hong Suk Chang (Hyundai Motor)

This study proposes a new BIW structure for a compact-sized electric bus, achieved through stiffness analysis of the body in the concept stage using a 1D beam model, sensitivity analysis, and optimization processes. The 1D beam element-based analysis offers more flexibility in shape modification, model construction, and analysis time compared to 3D shell element-based analysis. Results: 1)Selection of critical components and proposal of optimal cross-sectional sizes, 2) Lightweight proposals through sensitivity analysis of component, 3) Proposal of target-based stiffness optimization concepts 4) Enhancement of the contribution of analysis before the detailed design stage.

D-WPT Installation and Characteristic Changes Due to Surrounding Environmental Factors

Jin Katsuya･Takeshi Hoshinoya･Kenichiro Takahashi (Honda R&D)

Proposing a burial method, verifying the influence factors due to the actual environment (soil, snow, asphalt pavement, etc.) with actual equipment, and evaluating changes in characteristics after 100,000-wheel durability and pavement roadbed evaluation before applying to general roads. We will make suggestions regarding inexpensive installation methods.

Feasibility Study of Onboard PV for Commercial Vehicle Application (2nd Report)
-Estimation of the On-board Effect of PV Systems by Simulation-

Shuai Pei･Jingxuan Peng･Kimiyoshi Kobayashi･Toshio Hirota･Yushi Kamiya (Waseda University)･Hidenori Mizuno･Takashi Ohzeki (AIST)

As an EV community bus field test was conducted in Iizaka Onsen area, Fukushima, EV’s energy consumption and solar irradiance under various driving and weather conditions were measured. Then, simulation models were developed to analyze the impact of EV energy consumption and PV generation, which are under different ambient temperatures, solar heights and driving conditions, such as various driving distance and route slope. Finally, the potential for electric energy reduction with installation of PV system was evaluated.

Benefit and Challenge Analysis of EVs Integrated with Photovoltaic Systems

Hidenori Mizuno･Katsuto Tanahashi･Takashi Oozeki (AIST)

This study focused on EVs especially used as delivery service vehicles, to analyze the potential benefit of integrating photovoltaic systems to the EVs and extract challenges to utilize such “PVEV” vehicles as efficiently as possible.

A study of EMC Tests during 150kW Class BEV Charging

Akira Mori (Toyota Motor)

Although BEV charging power is becoming high rate, study of EMC testing methods has not progressed accordingly. Therefore, in order to study a standard test method that assumes high power charging, we used the Fukushima Renewable Energy Institute which has dedicated equipment. And we conducted EMC tests during 150kW class BEV charging. It was confirmed that when the charging voltage is constant, there is no current dependence of conductive and radiated emissions.

Proposal on Method of EV Integrated Thermal Management System Comparison and Development Trend
-Comparison between HMC Ioniq 5 and Tesla Model Y-

Hosik Lee･Sukjoo Kim･Chiheon Song･Byungsoon Min (TENERGY)

The technology that has the greatest impact on the low-temperature driving range of electric vehicles is the thermal management system. In order to improve the efficiency of thermal management system, the system configuration is becoming more complex, with system such as heat pump system and waste heat recovery system. In this study, we propose a method for comparative analysis of the thermal management systems by vehicle, and summarize the results of the analysis using the Hyundai Ioniq5 and Tesla Model Y as examples.

Reducing Energy Losses in xEV Motors and Batteries through CO₂ Refrigerant Utilization for Lubrication and Thermal Management

Shoko Horibata･Yuma Miyauchi (Mazda)

Generally, motors, batteries, and air conditioning systems for xEVs are thermally managed through separate pathways for oil, water, and refrigerant. We are working on centralizing of these systems using CO2 refrigerant with electric insulation and low viscosity, enabling both direct cooling and lubrication simultaneously. As a result, we confirmed improvements in thermal management performance, reduction in both the friction losses of the shaft and the agitation resistance of the rotor.

Novel eAxle with Integrated Charging System for Electric Vehicle

Yoshihisa Kubota･Soumei Nakatomi･Takumi Todoroki･Naoya Naito･Keisuke Azusawa･Satoyoshi Oya (Honda R&D)

With the advancement of electric vehicle performance, the increase in electrical components needed to connect various power devices has led to problems associated with increased part count, weight, and cost. In this study, we developed a novel power unit that integrates AC charging and rapid DC charging functions by converting a three-phase motor to a two-phase motor using a drive inverter and motor. This paper reports on the operating systems of the drive and charging functions.

Pareto Solution Search of Unsprung Mechanical Transfer Characteristics and Control System for In-Wheel Motor Vehicle

Norihiro Sugimoto (The University of Tokyo / DENSO)･Sakahisa Nagai･Osamu Shimizu･Hiroshi Fujimoto (The University of Tokyo)･Yusaku Ishiguro･Isao Kuwayama (Bridgestone)

In-wheel motor vehicle can control the sprung vibration by utilizing the suspension reaction force by the driving force. However, the optimization considering the mechanism parameters such as the sprung weight and the tire spring constant as variables has not been carried out. In this study, performance optimization such as riding comfort by simultaneous design of mechanism and control using 1D-model was proposed.

Method for Evaluating the Ductile Crack Propagation Properties of Steel Sheet under Tensile Stress Conditions

Asato Hatamoto･Hiroshi Shimanuki (NIPPON STEEL)

During collisions, base metals may incur ductile fracture without evident defects under complex stress conditions. Herein, we propose a test method for evaluating the propagation behavior of internal ductile cracks in metals under tensile stress conditions. The applicability of the developed specimen to the evaluation of ductile crack propagation properties was discussed based on the results of tensile fracture tests and finite element analyses.

Fatigue Strength Evaluation of Lap Fillet Welded Joints using Infrared Thermoelastic Method

Hideki Ueda･Taizo Makino･Hiroshi Shiromizu (Nippon Steel)･Reiji Tanaka (Nippon Steel Technology)

We investigated the effect of load frequency using thermoelastic finite element (FE) analysis on Lap fillet arc weld joint commonly used in automobile parts. To simulate the thermoelastic effect, we developed a stress field-temperature field thermoelastic FE analysis technique that calculates the heat transfer of heat generation and heat absorption according to compression and tensile stress. The calculated stress distribution showed a good agreement with thermoelastic stress distribution measured using an infrared ray method. Moreover, we verified the accuracy of estimating the fatigue limit obtained from the point of sudden increase in dissipated energy by infrared measurement.

Effects of Tension and Bending Loads on the Fatigue Threshold in a Stainless Steel Sheet

Gyoko Oh (Tokyo Roki)

By conducting fatigue tests with different loading modes using specimens with different notch lengths, we clarify and propose the criteria for fatigue thresholds. Cyclic plastic strain occurred near the notch, and was larger under tensile load than under bending load. The fatigue limit under tensile load was lower than under bending load, and there was a knee point on the relationship line with notch length. A calculation model for the critical stress intensity range ∆Kthc was presented. It was revealed that ∆Kthc varies greatly depending on the load type, but remains constant regardless of the length of the notch or crack.

Improving the Fatigue Limit of Spot-Welded Tensile Shear Joints Made of High-Tensile Steel Sheet (First Report)
-Improvement of Fatigue Limit due to Single Overload-

Akifumi Okabe･Tatsuya Ito･Noboru Tomioka (Nihon University)

A single overload was applied to spot-welded tensile shear joints using 590 MPa class high-strength steel as the base metal, and the effect on fatigue life was investigated. A large bending deformation occurred near the nugget edge of the tensile shear joint due to a single overload, resulting in large compressive residual strain on the inner surface. This is the reason for the improvement of the fatigue limit. In the case of a constant amplitude load range, a single overload increased the crack initiation life by 5 times and the crack propagation life by 2 times.

Improving the Fatigue Limit of Spot-Welded Tensile Shear Joints Made of High-Tensile Steel Sheet (Second Report)
-Fatigue Life Assessment based on Effective Strain Range-

Tatsuya Ito･Noboru Tomioka･Akifumi Okabe (Nihon University)

In this study, fatigue tests were conducted on spot-welded tensile-shear joints using 590 MPa-class high-tensile steel sheet as the base material, with various load ratios in the constant amplitude load range applied following a single overload, and the threshold load ratio at which the effect of the single overload disappears was experimentally determined. This threshold gives the effective strain range for fatigue damage, and it was shown that this effective strain range can be used to uniformly evaluate the fatigue life with and without a single overload.

Development of the Steel Sheet Battery Housing Concept (1st Report)
-Study of the Load Transfer Structure using Undercover-

Sadao Miyazawa･Shuki Nakamura･Artur Rekets･Kenichi Watanabe (Kobe Steel)

This paper reports a steel sheet battery pack structure with an uneven bottom surface of the tray.
This structure has a load transmitting path and cooling system using an undercover in the uneven tray space to reduce a battery pack height.

Development of the Steel Sheet Battery Housing Concept (2nd Report)
-Forming of the Cross Member with Complex Shapes using Hydraulic Presses-

Shuki Nakamura･Sadao Miyazawa･Rekets Artur･Kenichi Watanabe (Kobe Steel)

In this study, a forming method for the cross member used for the steel sheet battery housing was studied. The cross member has complex shapes with a continuous flange at the end, in addition to the shape given to the sidewalls to avoid the uneven bottom surface of the housing. The cross member was formed by hydraulic forming.

Development of Delayed Fracture Prevention Technology for 1470 MPa Class High-Strength Steel Sheet Parts

Kentaro Kobari･Kazuki Ishiguro (Suzuki Motor)･Yosuke Honda･Ryuji Shibue (BELLSONICA)･Shinnosuke Nishijima･Takayuki Nozaki (NIPPON STEEL)

In the development of steel plate press parts, the prevention of delayed fracture caused by the electrodeposition coating process and the corrosive environment in the market becomes an issue as the strength of materials increases. In the development of 1470MPa ultra high strength steel parts for new models, we report our efforts to prevent delayed fracture using CAE analysis.

Evaluation Method for Delayed Fracture of Steel Sheet by Four-point Bending Specimen
-Influence of Baking Treatment on Delayed Fracture Resistance in Ultra-high Strength Steel Sheets-

Junya Tobata･Hideyuki Kimura･Yuichi Matsuki･Toyohisa Shinmiya･Kouhei Ikeda･Kazuki Matsubara･Masanari Tomozawa (JFE Steel)

It is known that the delayed fracture resistance of cold-rolled steel sheets for automotive body structural parts is improved by Bake-hardening (BH) treatment. In this study, we investigated the changes in the microstructure of the steel sheets during BH treatment and the changes in the amount of hydrogen within the steel sheets after immersion testing by BH treatment. We also discussed the mechanism of improved delayed fracture resistance of the steel sheets due to BH treatment.

Prediction Method for the Edge Fracture of Steel Sheet Parts in the Automotive Crash

Yuki Taguchi･Kazuyuki Hamada･Mie Tachibana･Shota Chinzei (Kobe Steel)

The formability decreases as the strength of the material increases, which increases the risk of damage at the edge of the parts on the car crash. This paper reports the results of determining the fracture limit of the edge at various strain gradients in the basic test, and verifying the fracture prediction accuracy considering fracture limit of the edge in crash simulation.

Evaluation of Heat Exchanging Performances through Aluminum or Stainless Steel Plates for Thermal Management Parts

Atsutaka Hayashi･Jun-ichi Hamada (Nippon Steel Stainless Steel)･Tsuyoshi Tamogami･Akira Onishi (Nippon Steel Technology)

Heat exchange performances through aluminum or stainless steel plates were evaluated for thermal management parts. 0.5 to 2 mm thick those plates were used. Heat was input to one side of the plate, conducted through the plate, and transferred to running water on the other side of the plate. When the thickness was thick, heat exchange performance of aluminum plate was higher. However, when the thickness was thin, that of stainless steel was almost same as that of aluminum and it was considered that it depended mainly on heat transfer due to water flow.

Research on Complete Recycling Technology for Aluminum Recycled Alloys

Ryo Wakabayashi･Yasushi Mashiyama (Honda R&D)･Hiroaki Funada (Honda Trading)･Shinichi Satonaka･Satoshi Kato･Takamitsu Satake (Honda Trading Aluminum)

Aluminum alloys for automotive power units are mainly manufactured from scrap, but contain iron parts. Therefore, thermal diffusion occurs in the molten metal during alloy manufacturing, which can increase the amount of Fe. In addition, scrap in the market can also be found to have a high Fe content, making it necessary to reduce the amount of Fe. In this study, we developed a technology to reduce the amount of Fe that can be fully recycled without relying on cascade recycling.

The Influence of the Forming Strain in Crash-bead Forming on the Axial Crash Bahavior of Aluminum Alloy Extrusion

Shun Takenaka･Taiki Yamakawa･Narikazu Hashimoto (Kobe Steel)

Aluminum alloy extrusion products can be designed with bead shapes in order to control the deformation mode. In this study, bead forming and axial crush simulation were conducted to clarify the influence of fracture and pre-forming on axial crush behavior.

Elucidation of Wear Mechanisms of Al-Sn-Si Alloys for Sliding Bearings under Lubricating Conditions

Jun Sahashi･Tomomi Honda･Tomohiko Kon (University of Fukui)

The seizure phenomenon of Al-Sn-Si alloys under lubricating conditions with additives was investigated via tests performed on a sliding bearing. Wear primarily occurs at the apex of the bearing. However, unlike in certain worn areas, there is no formation of a black boundary film, as observed in linear contact tests. The coefficient of friction and contact electrical resistance change in a manner consistent with observations from linear contact tests.

Development of Life Prediction Technology for Lead Wire Solder Joints using an S-N Curve

Shunsuke Sakai･Takashi Furukawa･Rie Aoyagi･Daisuke Kiryu (Yamada Manufacturing)･Takashi Yamazaki (Yamada Auto Parts Research & Development)

Strain in the solder joint was predicted by performing CAE anaylsis on a 3D model of a solder joint with lead wire which replicates the fracture state observed in a solder fatigue test, and an S-N curve was created.In order to verify the validity of this method, solder fatigue tests were conducted on a circuit board for a small motor, and it was confirmed that the actual fracture locations, strain concentration location CAE results, and fracture cycles were in good agreement.

Systems using Vehicle-in-the-Loop Simulation Institute for Traffic Accident Research and Data Analysis

Seonghun Kim･Seungmin Kwon･Yong-Sub Yi･Hyoungjun Ahn･Giin Jang･Hanjun Cho･Minwoo Han (Hyundai Motor)

This paper presents a new approach for evaluating the functional safety of a SbW(Steer-by-Wire) system, focusing on creating an efficient and safe testing environment for drivers. It introduces the Vehicle-in-the-Loop Simulation (ViLS) using the Handling Roadway (HRW) test rig to assess the functional safety of SbW system. The study validates the correlation between ViLS and proving ground results, analyzes deviations in test results, and suggests methods to improve the efficiency of ViLS testing. These solutions establish criteria for the Fault Tolerant Time Interval (FTTI) and hazard standards, which are applied to the development process of SbW systems.

Active Safety for Farm Tractor based on Nonlinear Dynamics
-Visualization of Tractor Rollover Accident Mechanism using a Tractor Simulator-

Kenshi Sakai (Tokyo University of Agriculture and Technology)

In agricultural tractors, typical deterministic chaos such as sub-harmonic resonance and/or stick-slip occur due to the collision/friction process between the tires and the road surface. The 120 annual fatal accidents caused by agricultural vehicles is the greatest risk to the sustainability of agriculture and food production. For active safety measures, we developed a tractor simulator to visualize the mechanism of tractor overturning accidents.

A Study on the Interior Conditions of a Route Bus that Lead to Passenger Injury Accidents Inside the Vehicle

Chiharu Kato･Tetsuya Hirota･Takeshi Sawada･Toshinari Nakai (Tokai Rika)･Yuta Uchimura･Tadashi Kosugi･Takashi Iwata (Kawasaki Tsurumi Rinko Bus)

Every year, about 300 passenger injury accidents inside route buses occur across Japan. To reduce the number of accidents, bus drivers are required to announce safety reminders to passengers thoroughly via microphone and diligently check the interior mirror. This has led to an increased burden on the drivers.
In this study, we collected video data from inside a route bus operating in Kawasaki City, and analyzed behaviors that could potentially lead to passenger injury accidents.

Study on Strength Estimation of Spot Weld and Efficient Data Expansion Method using Gaussian Process

Taisei Akagi (Hiroshima University)･Yuki Okumoto･Akira Naito･Kosuke Kojima (Mazda)･Yoshikazu Tanaka (Hiroshima University)

The spot weld strength is directly related to the strength of car bodies. However, it is time and labor intensive to acquire data of spot weld strength from fracture tests due to the large number of conditions. In this study, a prediction model using Gaussian process is developed and a data expansion method that can numerically determine additional test conditions necessary for estimating strength accurately is investigated to save labor in acquiring the data.

Multi-Step Shape Optimization Method using Isogeometric Analysis

Mizuki Hoshino (University of Yamanashi)･Shin-ichi Arimoto･Kosho Kawahara (Toyota Motor)･Ki-ichi Furuhashi･Kyohei Noguchi･Yuta Yokoyama･Hirofumi Sugiyama･Shigenobu Okazawa (University of Yamanashi)

To achieve global shape optimization using Isogeometric Analysis, we develop a scheme that automatically repeats optimization and changes the number of control points. By updating the number of control points and search area step by step, the design space can be widely explored while avoiding shape breakdown. Evaluate the performance of the derived structure using example calculations.

Development of Triboelectric Power Generator Mounted in Tire for Tire Pressure Monitoring System

Hiroshi Tani･Shinji Koganezawa･Shohei Kawada･Renguo Lu (Kansai University)

A triboelectric power generator that can be attached to a tire was developed as a power source for a tire pressure monitoring system (TPMS). The structure of the generator was determined according to the size of the tire, and power generation of more than 200 μW was confirmed at speeds of 20 to 80 km/h during actual driving. The operation of the TPMS was also confirmed.

Ventilation Performance of BEV Route Bus

Koichi Tatsu (Isuzu Motors / AIST)･Naohide Shinohara (AIST)･Jyun Sakaguchi (University of Niigata Prefecture)･Hoon Kim (National Institute of Public Health)･Naoki Kagi (Tokyo Institute of Technology)

We have been developing an aerosol filter as an effective infection control measure for public transportation. However, the introduction of aerosol filters is expensive, so they are not widely used. Therefore, we conducted a verification of effects other than infection control. We will also report on the ventilation performance of Japan's first BEV route bus equipped with this aerosol filter as standard equipment.

Particle Reduction by using Medium Performance Filters in Public Transportation Vehicles and Identification of Collected Particles

Naohide Shinohara (AIST)･Kazuhiro Hashimoto (FCG Research Institute)･Jun Sakaguchi (University of Niigata Prefecture)･Koichi Tatsu (Isuzu Motors)･Hoon Kim (National Institute of Public Health)･Takashi Nishitani (Japan Vilene)･Kento Takami (TOYOBO MC)

We evaluated the effectiveness of medium-performance filters to reduce particles in the cabin indoor air and their performance changes over time when the filters were installed in the air conditioning of buses. We also identified and quantified the particles (metals, microorganisms, etc.) collected by the filters after using in actual operation.

Comprehensive Risk Screening for Chemicals in Car Indoor Environment based on qNTA

Masahiro Tokumura･Sota Sakai･Takeshi Enomoto (University of Shizuoka)･Kouichi Tatsu (University of Shizuoka / Isuzu Motors)･Naohide Shinohara (AIST)･Masakazu Makino (University of Shizuoka)

A variety of chemical substances are emitted from automobile interior materials, and there is concern about the health effects caused by these substances. In this study, a comprehensive risk assessment method for chemical substances in car indoor environment was investigated by combining quantitative non-target analysis (qNTA) of chemical substances with a method for predicting toxicity potentials.

Study on Quantitative Analysis of VOCs in the Air of Vehicle Cabin using Passive Sampling (Part2)
-Study on Quantitative Evaluation of 2-Ethyl-1-hexanol-

Kunihiro Hoshino (ENV Sciences Trading)･Koichi Tatsu (Isuzu Motors)･Masahiro Tokumura (University of Shizuoka)

We have reported that quantitative analysis of toluene, ethylbenzene, xylene, and styrene is possible using a passive sampler (POD Sampler). This time, we will report on the quantitative analysis of 2-ethyl-1-hexanol, which is a candidate substance for indoor concentration guideline values.

VOC Reduction and Management Activities in the Cabin

Keigo Kii･Masanao Kanaga･Tsukasa Shinohara (J-BUS)･Kouichi Tatsu (Isuzu Motors)･Naohide Shinohara･Aya Iwai (AIST)･Masahiro Tokumura (University of Shizuoka)･Kunihiro Hoshino (ENV Science Trading)･Shinsuke Usui (Kaneka Techno Research)

We are working on VOC reduction activities as part of our efforts to create cars that are considering the environment in the cabin.
The purpose of this activity is to provide all users with high-quality and low VOC emission vehicles.
This activity strive to improve technology that predicts VOC emissions in the cabin at the design stage and technology that suppresses and reduces the affect of pollution at the manufacturing stage.

Study of Alternative Carrier Gas for Gas Chromatography Mass Spectrometry
-Method for Analyzing the Cabin Air Chamber Quality by TD-GC/MS with Alternative Carrier Gas (2)-

Koichi Tatsu (Isuzu Motors)･Sadao Nakamura･Takeshi Serino (Agilent Technologies Japan)･Kunihiro Hoshino (ENV Science Trading)

Helium is a chemically inert noble gas used in thermal desorption-gas chromatograph/mass spectrometer (TD-GC/MS) to measure cabin air quality. As all of helium supplied in Japan is imported, there exists the risk in instability of supply. Optimization of analytical methods using nitrogen as an alternative carrier gas to helium was discussed.

Prediction of the Quantity of Vapor Displaced into the Canister during Automobile Refueling
-Prediction Formula for Vapor Displacement during Refueling-

Masanori Sakurai (Nissan Motor / Kanagawa University)･Yuji Yamada (Nissan Motor)･Hiroyuki Ito･Yuji Nakanishi･Toru Yamazaki (Kanagawa University)

Efficient fuel system design requires predicting the air entrainment flow rate into the fuel tank and understanding the mixed gas state changes. This study focuses on the vapor generated by entrained air, developing a formula to predict vapor displacement into a canister during refueling. The model includes gas state changes and displacement processes, applying gas laws and considering recirculation line effects and temperature variations. The derived formula accurately predicts vapor displacement quantities, as confirmed by comparison with actual vehicle measurements.

Fundamental Study of Gas Sensor Evaluation Method for Visualization of Vehicle Cabin Air Quality

Satoru Dohshi･Reiko Yamashita･Hinako Sakai･Yui Horiguchi (Osaka Research Institute of Industrial Science and Technology)･Naohide Shinohara (AIST)･Koichi Tatsu (Isuzu Motors / AIST)

In order to visualize vehicle cabin air quality, particularly VOCs and odors, it is essential to measure these concentrations continuously. For this purpose, it is necessary to employ gas sensors, although the sensitivity, resolution, and response to the guideline concentrations of VOCs in the vehicle cabin have not yet been clarified. This study reports the construction of an evaluation system designed to investigate the sensitivity, resolution, and individual differences of gas sensors.

Development of an Efficient Improvement Method for Thermal Boundary Surrogate Models using Fine-Tuning

Tomofumi Shimokawa･Mitsunori Kamimura･Norio Kawaguchi･Masakatsu Takahashi･Takahiro Mochihara (Toyota Motor)

Developed a surrogate model combining multiple regression and deep learning. Observed a drop in inference accuracy in new design areas. Used fine-tuning to improve accuracy and reduce learning costs, enabling better adaptation to new designs.

“Absorption” and “Bouncing” of Oil Mist Droplets Impacting on Oil Film

Hayato Ito･Koichi Nishino･Misa Ishimura (Yokohama National University)･Akira Nakashima･Masato Nishimura･Yusuke Kimura･Kazuhiro Nakamura (Mazda)

Sophisticated design of oil mist separators suitable for blowby gas of IC engine needs deep understanding of wall-adhesion behaviors of individual oil droplets impacting on the wall. The present study focuses on absorption/bouncing behaviors of oil mist droplets in a simplified oil mist separator and clarifies the absorption/bouncing transition and the bouncing probability by observing the behaviors of micro-sized oil droplets generated using a vibrating orifice aerosol generator.

Analysis of the Volumetric Efficiency Improvement Mechanism in the Gear Pump

Takashi Hashiba (SOKEN)･Masaaki Omi･Akira Kamada (Advics)

A compact and on-demand braking system has been developed for ADAS compatibility. The system uses a high-flow rate gear pump as the hydraulic power source, the pump for this system can achieve high volumetric efficiency by adjusting micro gap between gears.
　In this study, the volumetric efficiency improvement mechanism was clarified by analyzing the in-situ behavior of micro gap between gears and lubrication condition.

Stability Evaluation of R-1132(E) Mixed Refrigerants

Takashi Usui･Tomoyuki Goto･Yasufu Yamada･Takashi Yoshimura･Taichi Ozaki･Tomohito Inoue･Yasutaka Negishi (Daikin Industries)

We have developed R-1132(E) as novel HFO refrigerants with environmental compatibility and efficiency, and proposed R-474A (GWP<1) as mixed refrigerant. HFO refrigerants, including HFO-1123, are known to be decomposed by external energy. So, a lot of studies have done for decomposition reaction.
Therefore, we investigated the decomposition conditions of mixed refrigerants including R-1132(E) and obtained their physical properties. The examination result is reported.

Modeling of Arc-Discharge Phenomenon for Refrigerants in Motor-Driven Systems

Kengo Nagai･Yota Omizu･Kensuke Shibuya (Nagoya University)･Takashi Usui･Yasutaka Negishi･Tomoyuki Goto (Daikin Industries)･Koichi Shigematsu･Jun Imaoka･Masayoshi Yamamoto (Nagoya University)

HFO refrigerants, such as HFO-1123, and especially R-1132(E), which was recently registered with ASHRAE, are becoming more suitable for practical use. However, these refrigerants are known to decompose due to external energy sources. This paper aims to model the arc discharge phenomenon at the time of ground fault, which is the main cause of this decomposition. A detailed disassembly of an actual electric compressor used in automobiles was performed, wherein relevant parameters were extracted. Using these parameters, simulations of the motor drive circuit were performed to calculate the energy release during arc discharge.

Development of Air Curtain System to Improve HVAC Performance and EV Range for Next Generation Mobility

Shunsuke Shigeta･Yoshihisa Shimada･Takayuki Shimauchi (Toyota Motor)

In the context of the need for technological innovation for CASE, the decrease in EV range due to heating is one of the main issues affecting the utility of mobility. The rapid ventilation of the cabin air caused by opening the door for passengers at bus stops has a significant impact on thermal comfort and EV range, especially in the case of mobility used as shuttle buses. We have focused on this phenomenon and developed an air curtain system to solve the problem.

Development of Thin Air Conditioning Register by Airflow Diffusion Suppression Technology

Jun Yamaoka･Masaharu Sakai･Kaori Seki･Takahisa Fujii (DENSO)

In recent years, it has been required to reduce the thickness of the air conditioning register by reducing the thickness of the instrument panel for expanding the cabin space and the field of view, and by increasing the size of the display. The thinning of the outlet reduces the accessibility of air conditioning air due to air flow diffusion. This time, we verified the air flow diffusion mechanism by visualization experiment, etc. and developed and mass-produced the air flow diffusion suppression technology by the side flow.

Development of a Tool to Calculate Ventilation Volume for Minimizing Heating Power Consumption in XEVs and its Quantification
-Considerations for Ventilation Volume Adjustment Methods-

Masato Kurihara･Yuzuru Yoshinami･Koichi Yamagata･Munehiko Oshima･Masayoshi Tajiri･Shunichi Ishikawa (Nissan Motor)

In order to increase the all-electric range of BEVs, energy-saving air conditioning is required. One of the energy-saving methods is to keep warm air in the cabin (internal air circulation), but there is an upper limit to the ventilation volume control in order to guarantee anti-fog performance.
This time, we developed a physics model to calculate the minimum ventilation volume keeping anti-fog performance, and quantified the effect of ventilation volume control.

Development of Seat Heater Performance Prediction using Heat Transfer Model

Yasuhiro Ono･Ibuki Adachi (Toyota Boshoku)

In the development of vehicle seat heater performance, we are changing the method of determining performance using actual product to method of creating design concept using MBD to analyze heat transfer phenomena. The analysis uses 1D CAE, making it easy to understand the phenomenon and to confirm the influence of the components and the environment and to make measures for it. Using this method, we examined and considered the factors that affect performance.

Component-TPA on the Finished Off-road Vehicle for Modular Design

Norio Nakagawa･Ryota Horie･Soichiro Ikegami･Takuro Okazaki･Tomohiro Abe･Shuichi Nakagawa (Yanmar Holdings)

As the diversity of prime movers continues to grow, the applying the component-TPA to the finished off-road vehicles such as construction machinery and agricultural machines is ongoing to realize the modular design. In this study, the effects of the nonlinearity of accelerance in the forced vibration system excited by the prime mover and the condition number when identifying the blocked force using the inverse matrix method have been investigated.

Response Improvement of a Structural-Acoustic Coupled System using Operational Sensitivity Analysis

Mineto Hashiba (Nissan Motor)･Takuya Yoshimura (Tokyo Metropolitan University)

In this paper, we attempted to improve the response of a structural-acoustic coupled system using an Operational Sensitivity Analysis.
An operational stiffness sensitivity analysis is newly proposed and validated through an analysis using a FEM model.
An operational mass sensitivity analysis was also validated experimentally, and these results were compared with those of an Operational Transfer Path Analysis, which is a well-known conventional operational analysis, to demonstrate the usefulness of the sensitivity analysis．

Mass Placement Optimization for Improving Vibration Damping of Automobile Body

Ryo Ageba･Kazuhiko Higai･Tsuyoshi Shiozaki (JFE Steel)

The shift from internal combustion engines to motors in automobiles requires changes in the body structure to maintain vibration damping. The vibration frequency bands generated by the engine and motor differ, so the body needs to correspond to these frequencies. This paper explores using topology optimization to achieve optimal mass arrangement and improve vibration damping in car body design. By placing a mass of around 5 kg in an optimal position, the vibration level at the evaluation point was reduced by over 5 dB.

A Study on Structural Optimization by Varying Plate Thickness to Minimize Vibration Response Energy due to Displacement Excitation using FEM

Katsuhiko Kuroda (Nagasaki Institute of Applied Science)

Currently, there is a trend in the body parts of electric vehicles to reduce the number of parts by one-piece molding. In this paper, the target structure is a beam that connects the left and right joints of the suspension section and the thin plate at its bottom, and the objective function of the structural optimization method is vibration response energy, using a method of inputting moment excitation of base excitation by FEM, and the design variables are composed of grouped plate thicknesses.

Vibration Damping and Weight Reduction Technology for Automotive Doors using Thermoplastic Glass Fiber Composite Materials

Yue Hu (Foster Electric)･Yigen Zuo (TEIJIN)･Manabu Sasajima･Yoshiteru Uchida (Foster Electric)

This research focuses on the inner panels of doors, which are becoming lighter and thinner, and aims to suppress vibration and improve the acoustic quality of speakers by using lightweight and highly rigid fiber-reinforced thermoplastic resin. After confirming the vibration mode shapes that have a high degree of influence, we used topology optimization to examine the shape of the inner panel in order to effectively suppress the modes.

Construction of PBN (Pass-By Noise) Model using MBD (1)
-Construction of HEV 1D System Model for UN R51-03 PBN Driving Mode-

Hiromu Iwase･Go Endo･Shinta Nakazawa･Go Toshizane･Kenichiro Ogata (Honda Motor)･Junya Matsumoto (RYOMO SYSTEMS)

Vehicle substitution verification with Model-Based Development is an effective method to improve the efficiency of PBN verification.
To realize the vehicle substitution verification, 1D system model that can predict driving conditions specified by UN R-51-03 and comprehensive operating conditions of a powertrain is required.
This paper describes a modeling method for constructing the 1D system model.

Electric Powertrain Noise Simulation Method Considering Contact between Parts

Ryosuke Yamauchi･Yasuyuki Asahara (Nissan Motor)･Takashi Maeda･Shota Fubasami･Kensho Sakamoto (Estech)

In the prediction of NV of the electric power train, the influence of the modeling accuracy of the shaft system is large. In particular, it is necessary to consider the contact area of the bearing and the change in stiffness according to the magnitude and direction of the torque in order to improve accuracy. In this paper, we report an analysis method using physical property mapping considering contact for the purpose of improving prediction accuracy of motor noise and gear noise of EV motor.

Vibration Isolating Support System with Leaf Springs for Electric Compressor

Kazuhiro Hayashi･Takanori Suzuki･Kazuhide Uchida･Yasumasa Yamazaki (SOKEN)･Motohiko Ueda (DENSO)

A quieter electric car makes the noise and vibration transmitted by the electric compressor noticeable and uncomfortable.　Thus, anti-vibration mountings for the electric compressor are essential.　A conventional anti-vibration rubber rigid at low temperatures worsens the vibration isolation performance at low temperatures. However, the leaf spring features the flexible stiffness over a wide temperature range. The leaf springs are applied to the anti-vibration mountings. The innovative anti-vibration mountings reduce the vibration in a wide temperature range from low to high. In addition, the mountings reduce the interior noise caused by the compressor.

Verification of Cabin Noise Reduction Effect of Acoustic Vehicle Alerting System using Downward-facing Speaker with Duct

Yuji Miyata･Hideki Matsuoka･Hiroki Tagawa (Honda Motor)

It is essential for the Acoustic Vehicle Alerting System to efficiently deliver sound to the regulatory microphone with as low a speaker volume as possible so that the driver and passengers don’t feel uncomfortable inside the vehicle while satisfying the specified external sound pressure. Prediction of the transfer function from the downward ducted speaker to the microphone positions specified by regulations using acoustic CAE resulted in a practical accuracy and clarified the effective parameters and mechanisms of the system.

Study on Optimization of Acoustic Properties of Laminated Soundproofing Material Design Considering Temperature Dependence

Tatsuro Miki (Nichias)･Kazuhito Misaji･Suzaku Kawano･Ayumi Takahashi (Nihon University)･Masatake Onodera (Nichias)

Acoustic prediction in a high temperature environment is important in the design of sound absorbing materials around the engine and exhaust pipes. The purpose of this study is to design a laminated soundproofing material with optimal sound insulation properties by means of theoretical calculations considering air temperature and acoustic pipe measurements at high temperatures.

Examination of Predictive Control for Ride Comfort using Foundation Models

Ichiji Yamada･Akira Kato･Yohei Nagai･Kenta Miyoshi (AISIN)

In conventional ride comfort predictive control, lasers and other devices have been used for road surface measurement, but there have been issues with measurement accuracy and time delays. Additionally, the relationship between the subjective evaluation by passengers and the vehicle’s design parameters, or physical quantities such as response parameters, has not been clearly understood. This paper examines the use of a Multimodal Foundation Model and image scene understanding to propose an optimal ride comfort experience for passengers.

Study on Continuous Friction Characteristic between Tire and Road
-Measurement and Evaluation of μ-s Characteristics of Ordinary Roads in Snowy Conditions-

Ichiro Kageyama (Consortium on Advanced Road Friction Database / Nihon University)･Atsushi Watanabe･Yukiyo Kuriyagawa (Nihon University)･Tetsunori Haraguchi (Consortium on Advanced Road Friction Database / Nihon University)･Tetsuya Kaneko (Osaka Sangyo University)･Minoru Nishio (Absolute)

The μ-s characteristics of snow conditions on ordinary roads pose a major problem in terms of road traffic safety. Therefore, in this study, based on the results of the friction characteristics covered by snowy and icy roads at proving grounds, we evaluated the measurement results on ordinary roads in snowy conditions and verified the outline of the characteristics fluctuations.

Study on Continuous Friction Characteristic between Tire and Road
-Relationship between Environmental Data and Road Friction Characteristics-

Atsushi Watanabe･Yukiyo Kuriyagawa (Nihon University)･Ichiro Kageyama･Tetsunori Haraguchi (Nihon University / Consortium on Advanced Road-Friction Database)･Tetsuya Kaneko (Osaka Sangyo University)･Minoru Nishio (Absolute)

In a previous study, we reported a method for estimating the friction characteristics on snowy and icy roads using a friction measurement device between the tire and road. In this study, we examined a method for estimating these estimated friction characteristics using multiple environmental data, such as road surface images, that reflect the friction characteristics. In this study, as an initial stage of research, we compare and discuss the relationship between environmental data and friction characteristics on test roads, such as dry, compacted ice, and icy roads.

Analysis of the Influence of Aerodynamic Forces on the Stability of Weave Mode of Motorcycles
-Calculations using Recent Vehicle Specifications-

Takahiko Yoshino･Reiya Haraoka (KURUME INSTITUTE OF TECHNOLOGY)･Motohito Ueki･Noboru Yabe (Yamaha Motor)･Tsuyoshi Katayama (KURUME INSTITUTE OF TECHNOLOGY)

To analyze the effect of aerodynamic characteristics on weave mode stability using recent vehicle specifications. To analyze the effect of aerodynamic coefficient changes on the stability of the weave mode and to study the main mechanisms.

Motorcycle Position Measurement using Opposing Omnidirectional Cameras

Junji Hirasawa (National Institute of Technology (KOSEN), Ibaraki College)

The author proposes a non-contact position measurement method using omnidirectional cameras. This method involves installing two omnidirectional cameras oriented vertically opposite to each other to measure the position in the vertical direction. Furthermore, the author discusses a method to reduce horizontal errors occurring in the camera baseline direction using this height information.

Cycle-to-Cycle Variation Analysis of Gasoline Engine by LES (First Report)

Takayuki Ito･Masahiro Matsuoka (JARI)･Ryo Adachi (SUBARU)･Toru Takabayashi (Honda Motor)

The suppression of cycle-to-cycle variation is an important issue in improving the efficiency of gasoline engines. In this paper, multi-cycle simulation using LES are performed for a direct-injection gasoline engine, and the cycle-to-cycle variation of fuel concentration near the spark plug is compared between simulated and measured. This report focuses on the effects of grid resolution on simulation accuracy under different air-fuel ratio conditions.

Cycle-to-Cycle Variation Analysis of Gasoline Engine by LES (Second Report)

Masahiro Matsuoka･Takayuki Ito (JARI)･Ryo Adachi (SUBARU)･Toru Takabayashi (Honda Motor)

Large Eddy Simulation (LES) was performed on a gasoline engine under different fuel injection systems and operating loads. Comparisons were made with measured values of fuel concentration near the spark plug and in-cylinder pressure during combustion, and it was confirmed that the LES could generally reproduce the trend of cycle-to-cycle variations under different conditions. The effect of grid resolution on the prediction accuracy of cycle-to-cycle variations under each condition was also discussed.

Construction of Online Co-simulation Environment (4)
-Study of Model Granularity Migration Process for Thermal Management Control Optimization-

Kenichiro Ogata･Keijiro Koide･Shunichi Kubota･Naoaki Takeda･Yusuke Suzuki･Go Toshizane･Seiya Nakasako (Honda Motor)･Ryohei Sugamata･Mitsunobu Saito (Honda R&D)

In powertrain development, in addition to performance design that maximizes the reduction of CO2 emissions, efficient development process with no rework and MBD are also necessary. Furthermore, fuel economy performance that assumes actual usage environment is required, EPA 5 cycle which evaluates various environments as fuel economy performance evaluation has been applied. In the EPA 5 cycle performance prediction considering engine temperature is essential, and it is necessary to assume MBD from performance design stage to performance verification stage. This study summarizes transition from conceptual model described in previous report to detailed model and its utilization in vehicle development process.

Construction of Online Co-simulation Environment (5)
-Improvement of Thermal Plant Model for Enhancing Prediction Accuracy of Engine Coolant Temperature-

Seiya Nakasako･Keijiro Koide･Kenichiro Ogata (Honda Motor)

In a Co-Simulation environment, the accurate prediction of engine coolant temperature is crucial. However, the fluid behavior around the radiator in radiator fan operating conditions is complex, posing challenges for representation using a 1D model. This paper proposes a model enhancement method that considers airflow through the clearance between the radiator and surrounding components.

Improvement of Transient Air Volume Estimation Model for High-volume EGR Models

Toshiyuki Nakamura･Akihiro Katsuura･Yujiro Tsutsumi (Honda Motor)

This document describes the improvement of the transient air volume estimation model for models with large-capacity EGR. Based on the transient analysis of EGR gas and fresh gas using 1DSim, an air volume estimation model was constructed that takes into account the delay of the pipe volume after the EGR valve and the inter-cylinder deviation effect. By applying this model, the accuracy of air volume estimation during transients was improved and product quality was improved.

Indoor Evaluation Experiment on Perception of Automated Driving System Marker Lamps

Akihiro Abe･Yoko Kato･Michiaki Sekine･Yoshiro Aoki (NALTEC)

In WP29, discussions are being held regarding the requirements for "Automated Driving System (ADS) Marker Lamp" that indicates the status of ADS. As a foundational study to develop technical requirements, this study used the lamps with blue-green chromaticity specified by SAE J3134 for evaluation and conducted indoor experiment to examine their visual perception. This study also examined the perception of both those lamps and other vehicle lamps when they were lit simultaneously.

Differences between Moving and Static Images in a Vehicle to Communicate Safety Messages to Drivers
-Discussion of Visual Messages Issued by V2X System-

Akira Ohtani･Ryohei Homma･Kotoe Udagawa･Iori Yamaguchi (JARI)･Masaaki Abe (JAMA)

This study examined the differences in drivers’ behaviours when information from the V2X system was presented in the form of moving images and static/pictogram ones. Thirty drivers participated in the driving simulator experiment, experiencing an event in which a vulnerable road user(VRU) suddenly appeared at an intersection while driving. The results showed that though their total glance time as gaze behaviours for the moving images were longer than for the static ones, there were no significant differences in other drivers’ behaviours between them. The visual presentation in V2X system was discussed in terms of drivers’ distraction and their adequate behaviours.

Usability Evaluation of a Gaze-Controlled Traffic Flow Monitor under Imperfect V2X Communication Environment

Yudai Tobinaga･Yoshiyuki Tanaka (Nagasaki University)

The authors have proposed a traffic flow monitor using V2X technology that allows drivers to check the traffic situation around their vehicle. In this presentation, we propose a new traffic-flow monitor that can move according to the driver's gaze point. A series of driving tests using a driving simulator are performed to validate the effectiveness of the proposed traffic flow monitor in an imperfect V2X environment according to the percentage of other vehicles displayed on the monitor.

Effect of Metaphor Design of AR-HUD for Route Guidance on Driver Judgement at Intersections

Taiki Kobayashi･Kazushi Nio･Tatsuru Daimon (Keio University)･Nobuyuki Nakano･Fumihito Inukai･Akira Tanaka･Tadashi Shibata (Panasonic Automotive Systems)･Daisuke Nagai (Panasonic ITS)

This study aims to investigate drivers' directional judgments and psychological aspects at intersections when using metaphor for route guidance of AR-HUD. In the VR experiment, experimental conditions were consisted of yaw and roll angles of the metaphors and the number of metaphors. Participants approached a left-turn intersection which was divided to three directions while experiencing various combinations of metaphor design of AR-HUD, and then asked to judge what direction the metaphor indicated. Experimental data were analyzed and evaluated in terms of reaction time and psychological aspects.

Application of Visual Cue Stimulus Continuously Inducing Gaze Direction on Safety Confirmation of Pedestrian in Turning Left at Signalized Intersection

Takahide I･Masanori Takemoto (Seikei University)

This study designed a dynamic visual cue stimulus, which was displayed the peripheral visual field of driver and induced gaze direction side by side continuously, to prevent insufficient safety confirmation. In the driving simulator experiment, for applying the visual cue stimulus to safety confirmation of crossing objects when turning left at signalized intersection, three kinds of experimental factors were prepared: degree for inducing gaze direction, direction of moving driver’s head, and amount of steering operation during safety confirmation. We analyzed the difference of effect for inducing gaze direction from one side to the other side in these three experimental factors.

High-precision Registration Technology for LiDAR Point Clouds and Stationary Structure Point Cloud Maps to Improve Object Recognition Performance for Urban Autonomous Driving

Takashi Ikegami･Yuki Shiozawa (Nissan Motor)

In urban autonomous driving, it is necessary to accurately distinguish and recognize stationary structures such as buildings and vegetation near the road from moving objects such as vehicles and pedestrians. In this study, we developed a technology to accurately overlay LiDAR point clouds onto stationary structure point cloud maps by correcting temporal distortions in the LiDAR data and applying coordinate transformation using multiple landmarks such as poles. This technology enables reliable detection of moving objects.

Pedestrian's Trajectory Prediction with Fluid Dynamics for Urban Autonomous Driving

Kazuto Futawatari･Takashi Fukushige (Nissan Motor)

In order to achieve urban autonomous driving, it is necessary to make decisions on vehicle behavior near crosswalks where multiple pedestrians come and go in various directions. In this study, we investigated a method for predicting pedestrian trajectory that are essential for making decisions on vehicle behavior. The method assumes a flow field, utilizing the shape of the crosswalk and the road on the map as boundaries, to predict streamlined pedestrian trajectories from the sidewalk to the crosswalk.

Drivable Area Boundary Generation Method using Spatio-temporal Risk Map with Integrated Longitudinal and Lateral Control for Urban Autonomous Driving

Yuki Tanaka･Takashi Fukushige (Nissan Motor)

For autonomous driving system in urban area, it is necessary to ensure proper distance between ego vehicle and surrounding vehicles and to achieve smooth behavior. To achieve this requirement, this paper propose boundary generation method of drivable area using behavioral exploration in risk space-time map based on predicted trajectories of surrounding vehicles. This boundary is used for longitudinal MPC related to acceleration control and lateral MPC related to steering control. To confirm the effectiveness of this method, vehicle test driving is conducted in public road.

Stuck State Detection Technology in Remote Monitoring System for Urban Autonomous Driving

Jingze Dai･Masahide Nakamura (Nissan Motor)

In driverless autonomous driving, there is a possibility that the vehicle gets stuck due to the function or performance limitation. In this study, we propose a detection mechanism that can accurately and quickly identify the stuck state among stops in order to remotely assist in resolving the situation. The results of the experiment demonstrate that the proposal shortens the time required to resolve the stuck state and mitigates its impact on the traffic flow.

Research Project Regarding Autonomous Driving in the UK Named ServCity
-Lane Level Route Planning for Smooth Driving Based on Parked Car Detection by Infrastructure Cameras-

Yuka Yoshimatsu･Yuya Niwa･Narihiro Akari (Nissan Motor)

A car needs to make lane change to avoid parked cars at dense environment without delaying for autonomous driving at urban arterial road. This research propose method for deciding lane change point to avoid parking cars smoothly, assuming congested area based on parked cars detected by infrastructure cameras and quantifying lane change difficulty.

ODD and Ethics

Masao Ito (NIL)

The Operational Design Domain (ODD) definition for autonomous vehicles is the basis for confirming safety. In recent years, standards such as ISO 34503 have been streamlining the description of ODD. However, there is still room for the writer's discretion in the boundaries of the ODD. Furthermore, even within the ODD, there needs to be more discussion regarding ethical appropriateness, which we will organize.

Discussion of Operational Design Domain for Implementation of Co-operative Automated Driving in Mixed Traffic Environment on Public Roads

Keisuke Shimono (The University of Tokyo)･Yasuhiro Akagi (Nagoya University)･Makoto Morita･Shuichi Matsumoto･Masaya Segawa (Advanced Smart Mobility)･Mitsuaki Hagino (The University of Tokyo)･Shinji Akatsu･Hiroshi Tanigawa (JARI)･Masahiko Kato (AIST)･Kimihiko Nakano･Yoshihiro Suda (The University of Tokyo)

For the social implementation of automatic driving, mixed traffic conditions are also expected to be targeted. Since the feasibility of automated driving depends on the ODD setting and its explainability, the study process is also important. In this presentation, we will introduce the process of study toward the definition of ODD for automatic driving with the example of the Kashiwa-no-ha area where one of model area for the co-operative level 4 automated driving system implementation project.

Self-signal (Device for Deterring Traffic Jam)
-The Concrete Plan for Deterring Traffic Jam and the Verification Method for it-

Hideaki Oku (O.K. Tech. Lab.)

First the main case of traffic jam will be revealed. And next the demonstration method will be suggested that frequently jammed 2 points in close proximity on highway are focused and traffic jam of one side will be disappear, where applied the method of deterring traffic jam. The construction and function of the device for deterring traffic jam will be suggested. We can enjoy many benefits like improvement of logistics and so on.

Survey on the Regulations Critical for the Simulation of Unified Energy and Fleet Management in the Full-scale Diffusion of Commercial Electric Vehicles

Shota Miyoshi･Ichiro Sakamoto･Tomonori Hasegawa (NALTEC)

This paper presents a survey of regulations that may constrain the fleet and energy management of commercial electric vehicles. The survey intends for the development a simulation system for the optimization of society in the full-scale diffusion of commercial electric vehicles. The paper provides a comprehensive overview of the influencing regulations and the detailed restrictions by Act on Rationalizing Energy Use, Act on Promotion of Global Warming Countermeasures, Labor Standards Act, and Act on the Protection of Personal Information as the first results of the survey.

Directly Detecting αβ Phase Currents by Utilizing a New Coreless Current Sensing Method, Termed as “Magnetic Clarke Transformation”

Kosuke Kajita･Shotaro Karasuyama (Honda Motor)

In the conventional method of detecting UVW phase currents, a core is used to strengthen the magnetic flux within its own phase.
The purpose of this paper is to propose a new current detection method, the "Magnetic Clarke Transformation," that directly detects αβ phase currents without the need to use cores by utilizing the magnetic flux from the surrounding phases.

Increasing the Ability to Freely Arrange the αβ-phase Current Sensors using a New Coreless Current Sensing Method, Termed as “Magnetic Clarke Transformation”

Shotaro Karasuyama･Kosuke Kajita (Honda Motor)

This paper proposes a new current sensing method, “Magnetic Clarke Transformation,” that directly detects αβ phase currents instead of UVW phase currents.
This method makes it possible to consolidate busbars by utilizing the coreless current sensors, but its limitations are due to new layout constraints.
This paper details a method for improving the placement of αβ-phase current sensors.

Development of Nd-reduced Magnet and Beyond NdFeB Magnet for Automotive Motors

Noritsugu Sakuma･Akihito Kinoshita･Hyuga Hosoi･Akira Kato･Tetsuya Shoji･Yusuke Umetani (Toyota Motor)

The rapid increase in demand for electric motors may result in a shortage of materials such as NdFeB magnets.We have developed Nd-reduced magnet and beyond NdFeB magnet that has made it possible to significantly reduce the amount of Nd used. These magnets were applied to a small motor, and efficiency and torque were evaluated at room temperature to high temperature.

A Study on the Application of Ferrite Magnets in EV Drive Motors

Ryosuke Minegishi･Shunji Oki･Tomoaki Kaimori (Nissan Motor)

We focused on ferrite magnets, which are available at a lower cost compared to neodymium magnets and examined the possibility of applying them to high-speed drive motors with small power and high gear ratios. We incorporated measures to utilize weak magnetic forces while ensuring centrifugal force strength with the increase in rotational speed, and discovered a motor shape using ferrite magnets that can reduce costs compared to neodymium magnet motors.

Visualization of Oil Behavior to the Coil End of an Oil-cooled Motor using X-ray Computed Tomography

Masataka Tanase･Akinobu Kochi･Masanori Shimizu (Toyota Motor)

In recent years, the heat generation density of motors for automobiles has increased due the side effect of downsizing. However, cooling with a large amount of oil decreases efficiency. Therefore, a more optimal cooling design is now required.
We visualized the dynamic oil behavior in the coil end, which was previously difficult to measure, using X-ray computed tomography. Additionally, we conducted a validation with CAE to establish efficient cooling design technology.

Development and Practical Use of EiL (Engine-in-the-Loop) for Pollutant Emissions Performance Design

Motoki Takahata･Kenichiro Ogata (Honda Motor)･Ryohei Sugamata (Honda R&D)･Masayoshi Nishino･Toru Nakashima･Koji Yoshida (Honda Motor)

In order to achieve front-loading for powertrain development, it is necessary to predict pollutant emissions performance of full-vehicle in early stage of development. In this study, it is described a methodology for building an EiL environment by coupling of a concept model of hybrid powertrain and an engine testbed. In addition, this paper describes a prediction method of pollutant emission performance using EiL.

Modeling of Heavy-duty PTO Type Parallel Hybrid Electric Vehicle and Analysis on Fuel Economy Impact (First Report)

Norifumi Mizushima (AIST)･Kyohei Yamaguchi (Kokushikan University)･Toshimichi Takahashi (Meidensha)

A heavy-duty PTO (power-take-off) type parallel hybrid electric vehicle (HEV) model was developed using the OpenModelica which handles the Modelica language to analyze the fuel economy impact by the electrified powertrain. The first report presents an overview of the vehicle plant model and powertrain control model, as well as the parameter identification method and results of the motor/generator model for the parallel hybrid system based on vehicle measurement using a chassis dynamometer. The developed heavy-duty PTO type parallel HEV model enabled driving cycle simulations based on various hybrid powertrain control strategies.

Modeling of Heavy-duty PTO Type Parallel Hybrid Electric Vehicle and Analysis on Fuel Economy Impact (Second Report)

Kyohei Yamaguchi (Kokushikan University)･Norifumi Mizushima (AIST)･Toshimichi Takahashi (Meidensha)

Recently, electrification of the powertrain is required for heavy-duty vehicles as well. In this study, a heavy-duty PTO (power-take-off) type parallel hybrid electric vehicle (HEV) model for fuel economy simulation is developed using the OpenModelica which handles the Modelica language to analyze its fuel economy impact by the electrified powertrain. The second report first presents a method for identifying each component model using data measured on a chassis dynamometer. Next, the accuracy of the developed model is verified. Finally, the fuel economy impact for different hybrid powertrain control strategies is analyzed using the developed model.

Control of Internal Combustion Engine in Hybrid System for Small Race Car
-Experimental Consideration on Control Performance of Electronically Controlled Throttle System-

Hayato Yamada･Masamune Kobayashi･Yusuke Ebashi･Ikkei Kobayashi･Jumpei Kuroda (Tokai University)･Taro Kato (Tokyo University of Technology)･Keigo Ikeda (Hokkaido University of Science)･Ayato Endo (Fukuoka Institute of Technology)･Takayoshi Narita･Hideaki Kato (Tokai University)

Hybrid vehicles are powered by an internal combustion engine and an electric motor. This can improve the dynamic performance, and a high-performance powertrain can be considered. However, precise control is required, especially for the internal combustion engine, which is difficult to control. We proposed a system control using an electronic throttle and investigated its usefulness experimentally and analytically.

Study on Spatial Distribution of Displacement and Strain in Rubber Friction against a Stainless-steel Sphere

Toshiaki Nishi･Kyouhei Ueno･Tomohiro Nomoto (Tohoku University)･Shinya Sugisawa･Daiki Shin･Ken Yamaguchi･Isao Kuwayama (Bridgestone)･Takeshi Yamaguchi (Tohoku University)

In designing the slip resistance of vehicle tires, it is important to design rubber friction. The change in displacement and strain in rubber bulk would determine the friction behavior, but has not been clarified. In this study, the spatial distributions of these parameters were experimentally quantified based on a digital image correlation method.

Prediction Method for Appearance Evaluation of Molded in Color Plastic using Measurement/Simulation Data

Hiroyuki Kimoto･Minako Izumi･Hirotaka Sakamoto･Kunihiro Nobuhara (Toyota Motor)

For resin bonding materials, which are being developed as unpainted exterior panel materials for CN and new designs, it is important to control the color through composition. Color is evaluated by sensory evaluation, but there is little knowledge regarding the correlation between composition and color, and the current state of creation is through trial and error. In order to reduce the amount of trial and error involved, we have developed a technology that utilizes information science to predict the characteristics of composition and color that will pass the test.

Exploration of Metal-resin Bonding Mechanism by Simulation

Hiroki Inoue (Tosoh)

Injection bonding which is bonding between metal and resin is an insert molding method using surface-treated metal. Injection bonding has features such as high productivity and a high degree of design freedom; however, there are still many unclear points about this bonding mechanism. We tried to elucidate this unclear point using simulations.

Crack Propagation Analysis for Joint using Damage Model

Hirofumi Sugiyama (University of Yamanashi)･Shigenobu Okazawa (University of Yamanashi / Diver Technology)

Evaluating the strength of joints is necessary to deal with the multi-material components. Previous research proposes a concept and simple examples of a crack propagation simulation using a damage model to evaluate fracture problems from crack initiation to rupture in joints of multi-material components. This work, moreover, shows the validity of the proposed method is tested through several example problems, such as butt joints and single lap joints.

Method of Determining Parameters of Plastic Material for Collision CAE and Accuracy Verification by Impact Test of Interior Parts

Kazuya Suzuki･Toshiro Ohori･Masayuki Ishihara (Suzuki Motor)

In order to conclude the presence of a crack in plastic parts in CAE of vehicle collision, incorporation of appropriate physical property parameters into a material model that can represent the mechanical characteristics of the plastics is demanded. We will introduce a method of identifying the parameters to be incorporated into a plastic-specific model in generic CAE software from the results of general material tests. Furthermore, a case study where the accuracy was verified using impact tests of interior parts, will be presented.

Development of Plastic Materials for Striker-cap to Reduce Frictional Noise

Mingyun Chung･Daeki Chung (Hyundai Motor)･Sunghyun Myung (Kolon Plastics)

BSR noise originating from the striker-cap has been one of chronic issues within suspension system. This squeak noise arises from frictional interactions between the plastic striker-cap and the polyurethane bump-stopper of the shock-absorber. Its significance has been accentuated with the recent trend towards electrification. Nevertheless, research on frictional behavior between two plastic components has been rarely conducted, compared to plastic to metal or metal to metal. In this study, we focused on the development of plastic materials for the striker-cap with reduced BSR noise by manipulating additive materials in polyamide compounds based on friction theory.

Study on Thermo-chemical Aging Model and Field Lifetime Prediction of Plastic in Cooling Systems

Hyeongwon Park･Kyunghwan Oh･Jee Young Youn･Soonbeom Kwon (Hyundai Motor)

Plastics are increasingly used in automotive, targeting light-weighting and energy efficiency improvement. However, being susceptible to aging, they have less durability than metals, making accurate lifespan prediction crucial. Despite the use of thermal aging models like TTS and the Arrhenius Equation for accelerated life testing, their accuracy is compromised under complex conditions with multiple aging mechanisms. This study proposes a new aging model based on a modified Weibull function, validated across material, specimen, and component. This model enables accurate aging prediction, problem analysis, and new material lifespan prediction under suitable accelerated evaluation conditions.

A Study of CFRP Application on Vehicle Structural Components

Yuya Mukainakano (SUBARU)

As preparation for future large-scale weight reduction, we introduce the study which applied carbon fiber reinforced plastic (CFRP) to vehicle structural parts. One of the problems in the application of CFRP is reliability. We will introduce the study examples of dynamic fatigue strength tests and fatigue characteristics tests of structural adhesives to gain knowledge on the reliability of CFRP parts.

Development of Fire-resistant Thermosetting Resin Molding Compound

Kazu Koide･Hideaki Inokuchi･Ryoichi Igawa (Sumitomo Bakelite)

Thermosetting resins become non-melting by cross-linking reactions and exhibit superior fire resistance. We developed a fire-resistant molding material using phenolic resin to suppress the progression of thermal runaway in batteries. The developed molding material inhibits the progression of ashing under continuous flame contact from a burner, and also possesses good enough material flow for screw injection molding.

Evaluation of Filtration Performance Variation in Electret Air Filter

Satoru Kobori･Takashi Nishitani･Kazuho Taniguchi (Japan Vilene)･Kouichi Tatsu (Isuzu Motors)･Naohide Shinohara (AIST)

We evaluated the filtration performance of electret Melt-Blown filter media to reduce particle concentration in the cabin environment.  In addition, we analyzed filter media specification by the evaluation of performance variations over time and effects of electrostatic charge in the electret air filter.

Effect of Spray-spray/wall Interaction on Diesel Engine Combustion (1st Report)

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

Fuel spray injected into diesel engine cylinder develops with entraining ambient air. Air entrainment flow surrounding the spray side boundary interferes with that of adjacent sprays. And the spray interferes with piston wall and develops along the wall surface. Then the spray interferes with the adjacent sprays developing along the wall surface similarly. In this study, effect of each interference on combustion was investigated by using a single cylinder engine.

Effect of Spray-spray/Wall Interaction on Diesel Engine Combustion (2nd Report)

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

Fuel spray injected into diesel engine cylinder develops with entraining ambient air. Air entrainment flow surrounding the spray side boundary interferes with that of adjacent sprays. And the spray interferes with piston wall and develops along the wall surface. Then the spray interferes with the adjacent sprays developing along the wall surface similarly. In this study, effect of each interference on combustion was analyzed by using engine combustion CFD simulation.

Evaluation of the Exhaust Behavior on a Diesel Light Duty Vehicle during a Real Driving by an on-board FT-IR Analyzer

Noritsune Kawaharada･Hisakazu Suzuki (NALTEC)

Real driving emission (RDE) test has been introduced as a part of the type approval test for diesel passenger cars in Japan. The target substants at the RDE test are mainly CO2 and NOx. In this study, due to its high global worming potential compared to CO2, N2O emission was also focused on our real driving tests. An on-board FT-IR analyzer was installed with a conventional portable emission measurement system (PEMS) to a diesel passenger car. The exthaust emissions were measeured during the tests and the emission behavior of these substances were discussed.

An Analysis of Diesel Fuel Spray Characteristics with Higher Injection Pressure

Akihiro Kita･Ryotaro Seto･Tokuji Kuronita･Yoshiaki Nishijima (Aichi Institute of Technology)

Higher injection pressure is one way to improve exhaust performance on diesel engines. In a constant volume vessel, the momentum transition of diesel fuel spray from the nozzle was measured, and the injection velocity was calculated. The injection pressure condition was up to 400MPa. The injection velocity was also measured by observing spray penetration using a high-speed camera.

A Study of Exhaust Performance Improvement with Higher Injection Pressure

Ryotaro Seto･Akihiro Kita･Takaya Goto･Tokuji Kuronita･Yoshiaki Nishijima (Aichi Institute of Technology)

Higher pressure injection on diesel engines contributes to increasing spray momentum and improving spray atomization. Higher momentum and fine atomization promote fuel-air mixing resulting in soot reduction.
To verify the estimated mechanism of soot reduction, we measured exhaust gas characteristics by combustion tests using a single-cylinder engine. Actual measurement results show soot reduction with fuel injection pressure increasing up to 400MPa.

Evaluation of High Compression Ratio Achieved by Extending the Stroke Length on Heavy Duty Diesel Engine

Hiroaki Saito･Munemasa Hashimoto･Yoshinori Ishii･Hisashi Ozawa (Isuzu Advanced Engineering Center)

When the compression ratio is increased to improve thermal efficiency, deterioration of combustion and increase of heat loss are inevitable by reducing volume of combustion chamber, and the improvement of thermal efficiency is extremely small. In this study, the compression ratio was increased by extending the stroke length without changing the combustion chamber of piston by using a single-cylinder test engine. As a result, under the condition of equivalent excess air ratio, it was confirmed that the effect of improving indicated thermal efficiency was higher than reducing volume of combustion chamber without deterioration in combustion.

Study of Combustion Improvement by Ridge Shape for Spray Splitting

Kazunori Yoshitomi･Mori Ishii (Hino Motors)

This study provides a concept that improves the mixing of air into the fuel spray by applying a ridge-shape to the combustion chamber which splits the spray into two directions.
The shape was finalized from CFD calculations and heat release rate profiles experimentally obtained from single-cylinder engine bench test.
Improvement in thermal efficiency and reduction in smoke emissions were displayed, which is thought to be due to the splitting of the spray which increases the homogeneity of air-fuel mixture.

Effect of Operating Conditions and Fuel Properties on Nanostructure of Soot Particles from Diesel Engine

Yu Kuroshima･Mizuki Obara･Kazuki Inaba･Kazuhiro Hayashida (Kitami Institute of Technology)

The effects of operating conditions and fuel properties on the carbon crystallite size of soot particles in a single-cylinder diesel engine were investigated. The results showed that the carbon crystallite size increased with increasing high temperature residence time as the operating conditions were changed, regardless of fuel properties. And the carbon crystallite size with low aromatic content fuels was smaller than with the diesel fuel.

Study on Real Road Eco-driving Methods for BEV
-Effect of One-pedal Driving on Electric Energy Consumption-

Akira Kato･Kai Kato･Sena Fujisaka･Yihong Zhong (Teikyo University)

One-pedal driving allows you to control starting, decelerating, and stopping just by adjusting the accelerator pedal, and some users have reported that it improves electric energy consumption. We will use a typical BEV in Japan to drive around Utsunomiya city with and without the one-pedal function, and report on the effects it has on electric energy consumption characteristics.

Evaluation Review of a Chassis Dynamometer System for xEV Testing

Toshinobu Furuta (Meidensha)･Hisakazu Suzuki (NALTEC)･Isamu Inoue (Ono Sokki)･Yasuhiro Ogawa (HORIBA)･Hideyuki Kuba (Mazda)･Kenji Sato (Toyota Motor)･Yasuhito Takemura (Daihatsu Motor)･Masato Taniwaki (Suzuki Motor)･Shohei Nakagawa (Honda Motor)･Noriaki Nakate (Japan Automobile Transport Technology Accociattion)･Masaki Naruke (JARI)･Kosuke Tashiro (Mitsubishi Motors)･Takeo Horikawa (SUBARU)･Keiichi Masutani (Nissan Motor)･Akira Noda (Former Japan Automobile Transport Technology Accociattion)

In order to reproduce the actual driving conditions of an xEV on a 4WD chassis dynamometer, it is essential to appropriately reflect the unique power performance of an electric vehicle (especially the transient characteristics including sudden acceleration and deceleration) on the platform.
Therefore, we investigate and study the requirements of the 4WD chassis dynamometer required to evaluate the actual driving characteristics of xEVs and the concept of creating an evaluation method.

Optimization of Speed Change Pattern for Improving Electricity Consumption of Electric Heavy-duty Vehicles and Verification through Actual Vehicle Chassis Dynamometer Testing (Second Report)
-Derivation of Battery Internal Resistance and Cable Resistance Based on Actual Measurements and Additional Consideration of Those Losses-

Yiyuan Fang･Youta Morohashi･Wei-Hsiang Yang･Yushi Kamiya (Waseda University)

In this study, we focused on the eco-driving speed change pattern of electric heavy-duty vehicles. In the first report, we performed the optimization calculation of vehicle driving energy consumption starting from the energy output of the vehicle battery and used chassis dynamometer test data to verify the optimization results. In this paper, we report the results of a similar study with additional consideration of battery internal loss and cable loss.

Research on Hydrogen Flow Rate Measurement for Fuel Consumption Measurement of Heavy-duty FCV
-2^nd Report: Experimental Study to Improve Measurement Accuracy in Transient Test Cycles-

Hisakazu Suzuki (NALTEC)･Yukiji Ohkura (JAMA)

In order to investigate the measurement accuracy of hydrogen consumption using a Coriolis flowmeter, we conducted chassis dynamometer tests using a fuel cell vehicle. In this report, we used high-pressure hydrogen and a hydrogen flow meter with a pressure adjustment mechanism to improve measurement accuracy. As a result, even in the transient driving cycles such as WLTC and JE05, where past tests showed variations, test results by Coriolis flowmeter were obtained that closely matched the measured values using the gravimetric method, which was determined from the difference in the weight of the gas cylinder.

Domestic Trends of Environmental Regulations on Vehicle toward Decarbonization

Takahito Nishimoto (MLIT)

CO2 emissions from vehicles accounted approximately 15% of Japan's total CO2 emissions at FY2021, and, reducing CO2 emissions from vehicle and improving fuel efficiency are important for climate protection. The international and domestic trends of Environmental regulations on Light-Duty Vehicle and Heavy-Duty Vehicle will be presented in this presentation.

Verify and Replicate of Real Driving Wind Flows in Chassis Dynamometer

Nobunori Okui (NATIONAL TRAFFIC SAFETY and ENVIRONMENT Lab.)･Toshimichi Takahashi (Meidensha)

At the development of the internal combustion engine vehicles, we usually use the chassis dynamometer. The engine of these vehicle is cooling by using the cooling blower. About the electrified vehicles (EVs and FCVs), it is necessary to manage the thermal energy by all the vehicle components when it is driving. Therefore, we need to replicate the real driving wind flows at the whole vehicle by using the cooling blower. In this test, we modified the outlet of the conventional cooling blower and verified the effect of it by using the engine vehicle and the electrified vehicle.

Impact of Vibration Applied to the Vehicle by the Hub Nut Clamp Type Vehicle Restraint Device

Toshimichi Takahashi･Morio Onai･Toshinari Kozeki･Nobuo Okazaki (Meidensha)･Masao Furusawa (F-MA Consulting)

A hub nut clamp type vehicle restraint device is used to secure a vehicle on a chassis dynamometer during testing of completed vehicles. Due to the structure in which bolts are fastened to the wheel hub, vibrations that differ from those experienced on actual roads are generated. The effects of vibration on the vehicle were verified by conducting Operational Modal Analysis and Experimental Modal Analysis.

The Influence of Timing and Positional Relationship in Interaction with Autonomous Car on Decisions of Bicycle Drivers to Passing Through Intersection

Soushi Akanuma･Masanori Takemoto (Seikei University)

In order to realize autonomous driving in ordinary roads, this study dealt with interaction system between autonomous car and bicycle driver that would be the collision target. The interaction system, in which a left-turning autonomous car required a bicycle driver passing through a signalized intersection to slow down, was established in the experimental environment of a bicycle simulator. We analyzed the influence of the distance to the intersection and the positional relationship during the requirement on decisions of bicycle drivers to passing through the intersection.

Examination of Visual Information during Partial Take-over Regarding Safety Confirmation

Junya Ito･Masanori Takemoto (Seikei University)

In order to realize safe take-over in ordinary roads, this study designed a partial take-over that required drivers to conducting safety confirmation of undetected areas of the autonomous driving system and examined an appropriate type of visual information for promoting drivers to conduct safety confirmation. In the experiment, we assumed the situation that the autonomous driving system could not detect areas where crossing bicycles existed when turning left at a signalized intersection and analyzed the effect of displaying visual information on safety confirmation.

Information Acceptance Characteristics of Cyclists According to Traffic Environment

Noritaka Kobayashi･Hiroshi Yoshitake･Motoki Shino (Institute of Science Tokyo)

In providing information support to cyclists while riding to prevent accidents, there is a risk that cyclists may not be able to accept the support information due to the amount of information they process depending on the traffic environment. In this study, we aimed to design the amount of information and timing of information support and understood the traffic environment that influences cyclists' information processing and the characteristics of information processing in that environment.

Raising Awareness of Road Safety for Children by Experiencing Danger in Virtual Spaces
-Evaluation Index for Behavior on Road-

Chieko Nishizawa･Kazunori Ban･Shinichi Sakaguchi･Akira Kawaguchi (Toyota Technical Development)･Masae Kojima･Hirofumi Aoki (Nagoya University)

Traffic safety education requires children to think about the dangers of traffic accidents from their own perspective. We considered that learning through experience is particularly important for children, and we focused on experiences in virtual spaces and tried a road safety awareness program in which children themselves learn through their own experiences. We report the results of analysis of the behavior of children who experienced and examined the evaluation index of the behavior.

Development of a Driving Simulator for Rear-end Collision Prevention Education using the PLATEAU 3D City Model

Koshi Miyazaki･Mana Haruyama･Seina Maeno･Kaisei Shimizu･Toya Kumagai･Kazuaki Goshi･Masaki Hayashi･Yasuaki Sumida (Kyushu Sangyo University)･Katsuya Matsunaga (Kyushu University)

To prevent rear-end collisions, which are the most common type of traffic accident, it is necessary to educate drivers on how to maintain an appropriate distance between vehicles. In this study, we designed and developed a driving simulator that enables drivers to drive in a 3D space modeled on an actual cityscape by using the PLATEAU 3D city model, experience collisions caused by sudden stops of vehicles in front, acquire evaluation of driving, and view replays.

Effect of Reflective Information on Correcting Older Drivers' Overestimation of Their Driving Abilities

Mayu Yoshikawa･Akio Nishimoto (The University of Tokyo)･Hiroshi Yoshitake (Tokyo Institute of Technology)･Ryota Fujita (Mitsubishi Precision)･Motoki Shino (Tokyo Institute of Technology)

Correcting the overestimation of driving abilities is crucial for improving the safety of older drivers. To help them recognize this overestimation, we designed information for reflecting on their self-assessment after experiencing hazardous situations in a driving simulator. Providing information that compares the older drivers' self-assessment of their driving with evaluation results of their driving based on the driving performance of instructors has contributed to correcting the overestimation of their driving abilities.

Data Collection and Video Analysis of Elderly Driving Behavior using Dashcams

Yuji Ikeda･Masaru Kimura･Kaname Kimura･Hiroshi Shishido (Alps Alpine)･Yoshimi Sato･Miyuki Hirasawa (C's Lab)･Yasuko Inomata･Tsubasa Otsuki･Makoto Takahashi (Tohoku University)

The purpose of this study was to analyze the driving behavior of elderly drivers using dashcam data collection and video analysis. In the primary survey, driving behaviors and surrounding environments that could lead to potential hazards were analyzed. Furthermore, this report will cover the processes implemented to acquire specific driving scene data.

Responses and Visual Behaviors of Drivers in Car-to-Cyclist Collisions using a Driving Simulator

Yuqing Zhao･Yuki Nitta･Koji Mizuno (Nagoya University)

To understand the high accident rate of older drivers in car-to-cyclist collisions, a driving simulator experiment was conducted to investigate the relationship between visual behavior, braking reaction time, and collision rate among older and younger drivers. It was found that the longer brake reaction time of older drivers is due to their longer perception time for cyclists.

Evaluation Method for Acceleration Control for Pedal Error

Yuki Manabe･Toru Kojima･Kouichi Kitada･Kenji Morizaki (NALTEC)

In recent years, accidents caused by operating the accelerator and brake pedals incorrectly have become a social problem, such as accidents caused by elderly driver. An activity for establishment of a new United Nations regulation for acceleration control for pedal error (hereafter ACPE) have been carried out. In this research, ACPE evaluation test methods are examined and conducted tests using actual vehicles. Based on the results, issues and solutions for the test methods were discussed.

Proposal of Moisture Resistance Evaluation Method for Conformal Coating of Automotive Electronic Components

Jun Muto･Satoshi Kashiwabara･Hisao Nishimori･Yusuke Okano (Toyota Motor)･Seiji Sakata･Tai Horikawa･Norimitsu Sakai･Natsuki Kumagai (Nissan Motor)

Regarding conformal coatings to improve the moisture resistance of electronic components, there is no established method for evaluating moisture resistance after coating on a substrate, making it difficult to compare the performance of each material. In addition, it is necessary to test while applying voltage for a long period of time, which is a heavy burden. In this paper, we propose a unique drip test method to resolve these issues.

Moisture-proof Evaluation and Examination of Conformal Coating for Automotive Electronic Components

Seiji Sakata･Tai Horikawa･Norimitsu Sakai･Natsuki Kumagai (Nissan Motor)･Jun Muto･Satoshi Kashiwabara･Hisao Nishimori･Yusuke Okano (Toyota Motor)

The effectiveness of a preventive measure for moisture-proofing automotive electronic components through the use of conformal coating at the PCB surface is demonstrated. However, it is unclear which parameters are crucial for ensuring moisture-proofing efficiency. In this study, we present the results of a water drop test that highlights the differences between various materials used for conformal coating.

Evaluation of Autonomous Development using a Flat Type Dynamometer that can be Installed in the Tyre House of a Vehicle -First Report-

Yoshihisa Hojo･Yuichi Takasaki･Kohei Yasumoto･Kenji Terada･Rentaro Kondo (Toyo Denki Seizo)

We have developed a flattened dynamometer that can be installed in the tyre house of a vehicle.　
This dynamometer is steerable and can also house the vehicle's mechanical brake, which is 94 kW, 1000-2000 min-1 per wheel, with a maximum short-time torque of 1350 Nm.
This paper refers to the possibility of evaluating the development of autonomous, such as emergency braking and emergency avoidance, by placing this dynamometer on all four wheels.

Consistency Verification of Signal Processing for Millimeter-wave Radar using Physical Sensor Model and DIVP Simulation Platform (2nd Report)

Tadashi Naito･Miyo Okamoto･Kenichi Nukihara (Continental Autonomous Mobility Japan)･Yadhu Krishnan M K (Continental Automotive Components (India) Pvt.)

In order to perform reproducible simulation evaluations in various traffic environments, the simulation platform and the sensor model should accurately simulate physical phenomena. In the case of millimeter-wave radar, bumpers affect the propagation of electromagnetic waves, which varies with the material and shape of the bumper on each vehicle. This report shows the results of the implementation and verification of the impact of bumpers on the propagation of electromagnetic waves in the DIVP simulation environment.

SIL-HIL Hybrid Simulation Environment for Automotive Software Validation (Second Report)

Katsuya Tsuzuki (dSPACE Japan)･Andre Hildebrandt (dSPACE)･Rafael Yunis (dSPACE Engineering d.o.o.)･Fabian Bronner･Martin Ruehl (dSPACE)

As Software Defined Vehicles (SDV) become more common and ECU software becomes more complex, Software In the Loop (SIL) and Hardware In the Loop (HIL) validation environments are getting more important. In this study, we have investigated simulation performance in an environment close to the actual ECU functionality by creating a prototype hybrid simulation environment of SIL and HIL. The SIL-HIL Transition is also discussed.

Research on UWB Communication Interference Suppression for In-vehicle Wiring Harness-less

Makoto Okuhara (Denso Ten / Kobe University)･Hiroaki Yoshitake･Yuri Nishigaki･Tetsuya Nomura･Shigeki Mitoh･Kenshi Morikawa (Denso Ten)

In recent years, the increase in wire harnesses due to the advancement of automotive technology has become a concern. Utilizing wireless technology is crucial for environmental and cost reasons. This paper proposes Interference Suppression Arbitration Control （ISAC） to address radio wave interference, a key challenge in achieving wireless implementation via UWB. ISAC significantly improves the impact of radio wave interference.

Implementation and Evaluation of Real-time and Dynamically Reconfigurable Network Middleware to Realize Multiple Use-cases of SDV

Yuji Oishi (Hitachi)･Hafiz Hilman (Hitachi Astemo)･Goichi Ono (Hitachi)･Yasuo Sugure (Hitachi Astemo)

Software-Defined Vehicles (SDVs), which achieves flexible control of vehicles, require reconfiguration of network according to change for communications of the software. In this study, we implemented real-time and dynamic network configuration function as middleware on automotive-grade devices, supporting representative 3 SDV use-cases with change for communications such as addition of new software. The performance evaluation result is reported.

Proposal of Vulnerability Analysis Method in Accordance with ISO/SAE 21434

Keisuke Honda (Hitachi Astemo)･Yukiko Matsubara･Mutsumi Shimoda･Nobuyoshi Morita (Hitachi)･Yasuhiro Fujii･Makoto Kayashima (Hitachi Astemo)

Cybersecurity development in accordance with ISO/SAE 21434 is required for compliance with UNR 155.
ISO/SAE 21434 requires vulnerability analysis to be conducted, but does not provide specific procedures.
In this study, we have defined a CC/CEM-based procedure of vulnerability analysis, and further investigated automation by applying tools. We have applied these development methods to the product design and confirmed the feasibility.

Application for a LiDER System by using a Liquid Crystal Lens with Multiply-divided Ring Electrodes

Koji Kobayashi･Ryoya Takewaki･Shiryu Seki･Mikita Tsukui･Yuki Imai･Marenori Kawamura (Akita University)

We propose an application for a LiDER system by using a liquid crystal lens with multiply-divided ring electrodes. The optical phase difference of the LC lens was obtained by measuring interference fringes when the voltages were applied across the multiply-divided ring electrodes and bottom flat electrode. The focal length and the focused position of the light through the LC lens can be controlled by applying voltages to the electrodes without any mechanical movements.

Liquid Crystal Lens Systems with Multiply-Divided Circularly-Hole-Patterned-Electrodes and Four-Divided Circular-Electrodes

Ryoya Takewaki･Shiryu Seki･Kandai Tsukui･Koji Kobayashi･Yuki Imai･Marenori Kawamura (Akita University)

Liquid crystal (LC) lenses with tunable lens properties have been already reported. The lens properties can be electrically controlled with no mechanical movements. In this study, we propose a novel LC lens with multiply-divided circularly-hole-patterned- electrodes and four-divided circular-electrodes. The lens property such as the optical phase difference was measured by observing the interference fringes under crossed polarizers using a polarizing microscope. The focal length and the focused spot can be adjusted by applying voltages to the electrodes of the LC lens.

Development of Ceramic Electret and Application to Vibration Power Generation Device

Kazuhiko Kano･Takuya Igashira･Noriyuki Matsushita (DENSO)･Suguru Iwasaki･Yumi Tanaka (Tokyo University of Science)

We are developing an electrostatic vibration power generation device using electret, a material that retains charge semi-permanently, as a high-output MEMS independent power source for wireless sensors. In this lecture, we will introduce the development concept of a vibration power generation device and our efforts to develop electret materials using ceramics as a base material.

Early Software Maturity Approach in Dual Clutch Transmission Software Updated

Taiji Inoue･Nobuyuki Nishimura･Junpei Matsuda (Isuzu Motors)

In the development of the new Elf ISIM, the ECU (Electronic Control Unit) software was furbished. With the aim of early detection and countermeasures against potential defects in the software, the software which objectively monitors the behavior of TM was developed and implemented in the ECU. This paper introduces the effect.

Development of Resistant Design Method of Resin Case against Printed Circuit Board Overheating (Second Report)

Miwa Kawasaki･Tai Horikawa (Nissan Motor)･Hiroki Miyachi･Shintaro Yagi･Koki Koyama (F.C.C.)

We are developing a method for heat-resistant design of cases when the printed circuit board overheats, which is an issue when using a resin case. In order to carry out resistant design, it is necessary to quantify the amount of heat generated by the printed circuit board and the deterioration of the case material according to the amount of heat generated. In this presentation, we report the the deterioration of case materials during overheating of printed circuit board.

Improvement of Rotational Range of Trunk in THUMS, for Application to Crash Safety Evaluations in Diverse Occupant Posture

Yoshiki Takahira･Yojiro Iizuka･Hiroshi Miyazaki･Shigeki Hayashi･Hiroaki Imai･Yuji Nakane (Toyota Motor)

Autonomous driving could increase comfort inside a cabin, potentially leading to a diversification of occupant postures. The objective of this study is to improve a rotational range of the trunk in a human body model “THUMS” with the perspective of crash safety evaluations for various postures. The adjustment of the paths of muscles around thoracolumbar helped improve the range of rotation. The result indicated the potential applicability of THUMS for evaluating a diversity of posture in a crash.

Improving Human Body Model Kinematic Fidelity in Far Side Impact using THUMS

Yojiro Iizuka･Hiroshi Miyazaki･Yoshiki Takahira･Shigeki Hayashi･Hiroaki Imai･Yuji Nakane (Toyota Motor)

The use of human body models will expand in the future in virtual testing, which is being introduced in car crash safety evaluations. In view of its application, this research aimed to improve the fidelity of head kinematics in far side impact tests using the human body model “THUMS”. By modifying the joint stiffness, the fidelity of the head kinematics was improved, demonstrating the possibility of applying the THUMS model to virtual testing.

Pelvic Rotation of THOR and Hybrid III Dummies in Frontal Impact

Toshiharu Azuma･Yuqing Zhao･Koji Mizuno (Nagoya University)･Kei Nagasaka･Takahiro Suzuki･Idemitsu Masuda (Suzuki Motor)

Finite element simulations of frontal impact sled tests were conducted on crash test dummies THOR (50M, 5F) and Hybrid III (50M, 5F). All moments around the center of gravity acting on the pelvis were obtained. The time histories of these moments were analyzed to investigate the influence of the shapes of the ilium, ischium, and coccyx on pelvis rotation.

Two-dimensional Degenerated Model of Rider on Motorcycle Crash

Kazunori Maehara･Masashi Saito･Yoshiharu Wada･Takashi Sato･Takashi Saso･Masayoshi Okamoto (Honda R&D)･Terumasa Narukawa (Saitama University)

To understand the phenomenon of a rider's whole-body behavior during a collision between a motorcycle and a four-wheel vehicle, a two-dimensional degenerate model was created. The model consisted of five rigid bodies (head, helmet, upper body, sternum, and lower body), and knee position was constrained by a pivot that moves back and forth. Comparison with a full-scale crash test showed similar results for head displacement and chest deflection.

Improvement Accuracy of Chest Injury Prediction for Accommodate a Variety of Occupants

Ikufumi Matsuba･Toshimitsu Negishi･Shigeki Hayashi･Hiroaki Imai･Yuji Nakane (Toyota Motor)

Introduction of virtual testing is accelerating in many new car assessment programs recently aiming to assess the various occupant and impact conditions. The purpose of this study is to develop seatbelt model for frontal impact with various occupants.
The characteristics of belt force for various occupant size was allocated with remained belt in the retractor. The friction between the seat belt and the occupant was also studied.

Static Anthropometric Measurements and Dynamic Changes during Driving in Pelvic Angles of Seated Motor Vehicle Occupants

Yoshihiko Tanaka･Yuqing Zhao･Koji Mizuno (Nagoya University)･Masahito Hitosugi･Misa Tojo (Shiga University of Medical Science)･Yutaka Nakajima (Autoliv)･Kentaro Ogawa･Ryota Ishigaki･Hiroki Matsuoka (Autoliv Japan)･Masatoshi Usui (NALTEC)

Using an accelerometer-based angle sensor and a three-dimensional measuring instrument to measure the seating posture of car occupants, trends in pelvic angles for small occupants were investigated.
The same angle sensor was used to examine the change in pelvic angle as the occupant's posture changes during driving

Development of CAE Methodology for Improving Accuracy of Reaction Force under Multiple Conditions of Driver Airbag Model

Hiroshi Morikawa･Yuki Uchiyama･Shoko Kobori･Michihiro Yamagishi (Nissan Motor)

CAE technical development was carried out because CAE analysis required to reproduce the airbag deployment behavior due to the specification change for increasing frontal airbag energy absorption. In modeling, factors influencing the airbag deployment behavior were identified and the characteristics measured in the test, then were incorporated into the model to improve prediction accuracy.

Study on Traffic Accident Injuries for Manual Wheelchair Users based on Pedestrian Traffic Accident Statistics

Ryo Oga (National Research Institute of Police Science)

Research on traffic accidents involving manual wheelchair users is limited. In Japan’s traffic accident statistics, accidents involving manual wheelchairs are tallied as a category of pedestrians. Therefore, this report examines information on accidents involving manual wheelchairs using traffic accident statistics. It reports on the characteristics of traffic accident injuries to wheelchair users based on information such as the main parts of the body damaged.

A Scoping Review on Electric Scooter Collisions, Falls and Injuries

Akihiro Kido･Ryo Oga (National Research Institute of Police Science)

While electric scooters are gaining popularity, research on their collision and falling phenomena remains limited. This study presents a scoping review that included international research papers to organize studies related to electric scooter collision and falling phenomena. Additionally, it compiles knowledge about injuries resulting from these accidents.

A Study of the Mutual Safety for Vehicles and Bicycles on Road Traffic using Accident Statistics Data Analysis
-A Study of Cyclist Injuries in Collisions with Passenger Vehicles and Large Size Trucks-

Yasufumi Sekine (Fukuyama University)

As a principle rule, bicycles should ride on the roadway when there are both sidewalks and a roadway. However, if a bicycle and a vehicle collide, there is a high possibility that the cyclist will be killed or seriously injured. In this paper, accident statistics data on vehicle and bicycle collisions were analyzed and their characteristics were clarified. Based on the characteristics of these bicycle accidents, the author would like to discuss the desirable coexistence of automobiles and bicycles in road traffic.

Evaluation of the Effectiveness of an Approaching Bicycle Notification System using Smartphones

Yasunobu Yokoi (Toyota Motor)･Takeshi Kitahara (KDDI)･Tomoko Yasuni (Toyota Motor)･Kengo Kurosawa (KDDI)

Among bicycle-vehicle accidents, collisions at intersections without traffic lights are the most common. To prevent this accident, we have developed a bicycle approaching notification system that uses smartphones. In this study, with the cooperation of taxi and delivery drivers, we conducted an evaluation of the effectiveness and acceptability of this system notification on public roads. We also considered the accident reduction effect of deceleration using system notifications.

Study on Advanced Emergency Braking System for Electric Scooter

Hitoshi Toda･Hiroki Kato･Ryuta Sawaki･Takao Ogura (Mie Prefectural Police H.Q.)

Electric scooters are not subject to the Advanced Emergency Braking System(AEBS) control. However, brcause their silhouettes are similar to those of pedestrians, it is conceivable that the AEBS could be activated. The presence or absence of AEBS activation is important in traffic accident analysis. In this study, We clarified the behavior of the AEBS for electric scooters.

Effect of Cooperative Systems Utilizing Roadside Sensors on Automated Driving at Intersections

Hiroshi Yoshitake (Tokyo Institute of Technology)･Wataru Kugimiya (The University of Tokyo)･Motoki Shino (Tokyo Institute of Technology)

The effect of cooperative systems utilizing roadside sensors on automated driving was evaluated as a start toward realizing safe and efficient automated driving in mixed traffic. The evaluation results using numerical simulation targeting automated buses traveling at intersections revealed that the cooperative systems contribute to maintaining safety in improving the efficiency of automated driving.

Calculation Method of Safe Speed for Automated Buses on Straight Roads Considering Sensing Characteristics

Taichi Sawanobori (Tokyo Institute of Technology)･Takaki Yoshikawa (The University of Tokyo)･Hiroshi Yoshitake (Tokyo Institute of Technology)･Yoshio Matsuura･Masaya Segawa (Advanced Smart Mobility)･Motoki Shino (Tokyo Institute of Technology)

In order to operate an automated bus safely in various environments, we devised a method for calculating the safe speed that can avoid collisions with pedestrians when driving on straight roads. We calculated the safe speed by focusing on the time it takes for a pedestrian to enter the detection range and the time it takes for a pedestrian to be recognized after entering the detection range and by considering the sensing characteristics of the automated bus. The safety speed was applied to a real-world environment, and its usefulness was investigated.

Visualization of the Basis for Judgment of Object Recognition Models by Sensor Fusion of LiDAR and Cameras

Yuusuke Nishio･Tsubasa Hirakawa･Takayoshi Yamashita･Hironobu Fujiyoshi (Chubu University)

Detecting distant vehicles is essential for safe automated driving. Therefore, we constructed a multimodal 3D object detector using point clouds and images of traffic scenes reproduced by a simulator. By using a perturbation-based importance visualization method for the detector, we analyze which of the point cloud and image has a higher contribution rate in various scenes.

Camera-based Tightly-coupled Fusion for 3D Object Detection

Xiaoyu Wang･Yoshitaka Okuyama･Kota Irie (Hitachi Astemo)

Most current 3D object detection methods’ performances drop dramatically on pseudo-LiDAR from disparity estimation for the characteristics that the error of stereo depth estimation grows quadratically with depth. In this work, we propose to implement a tightly coupled fusion that estimates the corresponding 3D bounding box for each 2D detection bounding box by maximum a posteriori estimator that considers (1) the variation of the transformation matrix between camera coordinates and ego-vehicle coordinates, and (2) the distribution of the transformed pseudo-LiDAR point cloud on logarithmic coordinates. The experiments show that our approach achieves remarkable accuracy improvement in 3D object detection.

Evaluating the Accuracy of Object Detection Models in Scenes where Pedestrians are Present at Intersections

Yotaro Suzuki･Hidenori Itaya･Tsubasa Hirakawa･Takayoshi Yamashita･Hironobu Fujiyoshi (Chubu University)

Evaluation of object detection models for automated vehicles requires a large amount of evaluation data. However, collecting evaluation data in a real environment is extremely costly. Therefore, it is expected that a variety of evaluation data can be created by using a computer graphics environment. In this study, an evaluation scene is created using a DIVP simulator to evaluate the detection accuracy of an object detection model.

Machine Learning to Determine Vehicle Load Characteristics for Pedestrian Protection

Naoto Yamamoto･Ryo Ando (Mazda)

Vehicle crash safety design under exterior styling and space restrictions generally requires a time-consuming trial-and-error simulation process. This study demonstrates a machine learning-based methodology to instantly determine the optimal load-displacement characteristics and necessary space for pedestrian protection without repeated simulations, enabling engineers to quickly resolve the trade-off between crash safety and styling.

Deep Learning Method for Pedestrian Injury Severity Prediction using Dashcam Videos

Shouhei Kunitomi･Takashi Tagawa･Yuji Arai (JARI)

The goal of this study is to predict pedestrian injury severity using a deep learning methods based on dashcam video for Advanced Automatic Crash Notification System (AACN). The developed injury prediction model detected pedestrians according to their injury severity from dashcam images based on pedestrian behaviors during an accident, and correctly predicted their severity. However, false detection and no detection were observed for accidents such as nighttime, rainy weather, rare behaviors, and children.

A Study of a Head and Leg Injury Prediction Method in Car-to-pedestrian Collisions using Machine Learning

Daisuke Ito･Yuko Shimaoka･Ryoga Doe (Kansai University)

In this study, a head and leg injury prediction method in car-to-pedestrian collisions was constructed by using FE analyses and deep learning. Collisions between small adult female and sedan-type vehicles were supposed. A prediction model for HIC and a leg bending moment was built using time series data of pressure obtained from tube-type sensor inside bumper absorber during a collision as input data.

Advanced Safety Technology Evolution its Traffic Accident Reduction Analysis (Second Report)

Takashi Hasegawa (Toyota Motor)･Junya Suzuki･Yasunari Matsuzaki (Tokio Marine & Nichido Fire Insurance)

Using one year of insured accident data, the accident rates for Toyota and Lexus vehicles equipped with the third-generation Toyota Safety Sense and Parking Support Braking (based on around view camera) systems are calculated. Each of these results are compared with the previous generation systems. As a result, it was confirmed that rear-end collisions with vehicles and accidents with stationary objects in parking areas are reduced compared to the previous generation.

Study on D-Call Net Effectiveness by using ITARDA Macro Database with the Emergency Transport Database (The 3rd Report)

Toru Kiuchi (ITARDA)･Nobuo Saito (Japan Mayday Service)･Eiko Kagesawa･Hiroyuki Shirakawa (ITARDA)

At the last JSAE spring session, the authors reported the effect of reducing the F.D. recognition time using J-TAD Macro data and emergency transport data from 2019 to 2021.
Although the reduction effect increased from the previous study, a large effect in suburban areas could not be confirmed. Therefore, using the same database, the effect is reviewed again under the restricted conditions such as single vehicle accidents with the large vehicle deformation in suburban areas.

Analyzing Parking Lot Accidents and Evaluating Collision Avoidance Performance of AEB using the RCAR Test Procedure

Naoki Bessho･Yoshimasa Uchida･Hisashi Kusano (The Jiken Center)

Unlike the recent downward trend in personal injury accidents, property damage accidents are on the rise. To further reduce traffic accidents, it is essential to understand the actual situation, including property damage accidents. This report focuses on parking accidents, which constitute a large number of property damage incidents, and presents an analysis of accident situations. Additionally, the evaluation method for AEB (Autonomous Emergency Braking) systems developed by RCAR to address parking accidents is introduced.

Characteristics of Japanese Traffic Accidents in Frontal Collision and Side Collision

Yoshinori Tanaka･Naruyuki Hosokawa･Yasuhiro Matsui･Masatoshi Usui (NALTEC)

We investigated characteristics of traffic accidents in frontal collision and side collision occurred in Japan during 10-years period from 2013 to 2022. The analysis results in frontal collision accidents indicated that approximately 70% of fatalities were driver's seat occupants, of which proportion and fatality rate in male occupants were higher than those in female occupants. The results also revealed that in side collision accidents, approximately 30% of fatalities were occupants seated on the non-struck side of the vehicle, of which proportion and fatality rate in male occupants were also higher than those in female occupants.

Characteristics of Collisions between Cars and Bicycles at Intersections in Recent Years and Analysis of the Effectiveness of AEB for Cyclists

Kenji Kawaguchi (Institute for Traffic Accident Research and Data Analysis)

In recent years, the number of rear-end collisions has decreased due to the widespread deployment of AEB (Autonomous Emergency Braking) of passenger cars, and crossing collisions are the most common. Moreover, among these accidents, cyclists’ injuries were the most common. This report analyzes these accidents from various perspectives and identifies the factors and other characteristics. Also, the effect of bicycle AEB on the market were calculated and proposals for further reducing accidents and injuries were made.

A Research on the Cause of Rear Left Tire Drop-off Accidents of the Trucks

Yasumasa Shoji (YS Corporation)

Recently the tire drop-off accidents of trucks are increasing. The tires are mainly left and rear side. This phenomena has occurred and increased after the tightening method was changed from JIS method to ISO method, and the number increased about 10 times after the change. Many researches have been carried out but none of them explain why the accidents occur mainly on rear left tires. The author found the possible reason based on a general principle of nut self-loosening and reports it in this paper.

The Effect of Front Pillar Blind Spots on Visual Behavior at Intersections in an Immersive Driving Simulator

Yuto Takei･Shinya Okamoto･Hisato Fukuda (Gunma University)･Toshihiko Kozai･Tsutomu Iwase (Gunma University / SUBARU)･Masanori Yoshida･Kenichi Sato･Noriyoshi Matsuo (SUBARU)

This study focuses on the visual behavior of drivers. It experimentally investigates the effect of the blind spots around the front pillars on driving at intersections using an immersive driving simulator. As a result, it was confirmed that visual behaviors, such as the driver's head-turning, increased with the enlargement of the blind spots. The effect was evaluated using a visibility score based on these visual behaviors.

Evaluation of Driver Safety Checking Behavior when Turning Right

Shinya Kitayama･Manabu Otsuka･Koji Hamada (DENSO)･Wentong Yang･Shota Matsubayashi･Kazuhisa Miwa (Nagoya University)

We are developing an information provision system that adapts to the driver's cognitive state. In this study, the timing of departure was measured in a virtual environment in order to clarify the factors that cause a lack of confirmation behavior when turning right. It was suggested that an increase in waiting time tends to increase the number of right-turn decisions without noticing oncoming vehicles or crossing pedestrians.

A Study for an Evaluation Index of Driver Preparing Behavior toward Potential Risks

Takahiro Tanaka･Hitoshi Kanamori･Asuka Harada (Nagoya University)･Saori Noda･Taiji Kawachi･Koji Hamada (DENSO)

In this study, we defined drivers' preparing behaviors towards potential risks while driving into three categories: prediction layer, detection layer, and response layer, and attempted to extract preparatory behaviors included in each layer from residential road driving data using a driving simulator. Furthermore, based on the analysis results, we examined indexes for evaluating preparing behaviors in each layer.

Modelling of Drivers' Internal States and Transition Mechanism using Vehicle Driving Data

Maki Kishimoto･Toshihiro Osaragi･Shoichi Mihara (Institute of Science Tokyo)･Akira Funakubo･Yusaku Takeda･Masashi Yamamoto･Chikara Tanaka (Mazda)

To achieve safe and comfortable automobile traffic, it is crucial to suppress selfish driving behavior and promote cooperative and altruistic driving. Altruistic behavior in one driver can be contagious, enhancing the overall safety of the transportation system. This paper quantitatively evaluates drivers' internal states from vehicle driving data and models the propagation structure of driving behaviors.

Basic Study on Driving Support System using Visual Information to Predict Potential Risk

Yuki Sakuma･Takemoto Takemoto (Seikei University)

This study dealt with situation when passing through a parked vehicle and examined the effectiveness of a driving support system, which prompted to predict potential risks such as a travelling bicycle and the blind spot of the parked vehicle. In the driving simulator experiment, the system displayed visual support information on safety confirmation and driving operation for each hazard. We recorded driving behavior data of participants and analyzed lateral distance, vehicle speed and completing position of safety confirmation for each hazard.

Development of Haptic Interaction-Based Driver Guidance System

Shusaku Sugamoto･Satoshi Inoue･Takeshi Hamaguchi･Shintaro Saigo･Satoshi Handa (Toyota Motor)

Although driving support systems have contributed to enhanced convenience, there are instances where drivers find it difficult to accept the operations designated by the system, preventing them from fully utilizing it. To address this issue and enhance the value proposition of the driving assistance system in more scenarios, we developed a steering operation support control. This system is designed to make driving feel easier and more intuitive, without giving the impression that it is dictating the driver's actions. The effectiveness of this control was evaluated.

This study focuses on steering operation support control. This control does not autonomously achieve the target operation amount on its own; instead, it modifies the steering resistance based on the predicted driver operation amount calculated from data provided by external sensors installed on the vehicle. This allows drivers to improve the accuracy of their feedforward component of anticipated operations, using the changes in steering resistance as cues. It is hypothesized that this setup enables drivers to have a sense of driving skillfully on their own, while still receiving support.

Since it is not directly possible to measure the improvement in the feedforward component's accuracy of the drivers, the effectiveness of this approach was inferred from changes in the feedback component, corresponding to the adjustment amount in steering. These effects were verified through measurements conducted with experimental vehicles.

Visibility Evaluation during Curve Driving in Headlamp Beam Control Technology using Map Information

Shuhei Ota･Shusaku Takamoto･Takahiro Seki (Mitsubishi Electric)

Misalignment between the driver's line of sight and the headlamp beam can lead to reduced visibility, necessitating alignment even during curve driving.
Consequently, a beam control system adapted to the road shape based on current position and map information has been proposed.
Evaluation results revealed that occlusion, in addition to road shape, influences the direction of the line of sight, suggesting that headlamp beam control adjusted for occlusion would be ideal.

Analysis of Discomfort Glare Caused to Oncoming Vehicles by Changes in the Pitch Angle of Passing Beam due to Road Undulations

Yoshiro Aoki･Yoko Kato･Michiaki Sekine (NALTEC)

Although the light distribution of the passing beam is determined so as not to cause discomfort glare to the driver of an oncoming vehicle, there is a possibility that it may cause glare depending on changes in the pitch angle of the own vehicle and the positional relationship with the oncoming vehicle. In this study, we measured changes in the pitch angle of an actual vehicle driving on an actual road, and numerically analyzed the frequency and level of glare. The effectiveness of countermeasures using dynamic auto leveling was also examined.

Consideration of an Alerting Method using Positional Correspondence Between Seat Vibration and Attention Targets

Yosuke Uemura (Kyoto Institute of Technology)･Tetsuya Kitagawa･Ryuji Furumai (Fuji Seat)･Yukiko Nishizaki (Kyoto Institute of Technology)

An intuitive and less burdensome method of alerting drivers using seat vibration was investigated. Experiments were conducted with university students and elderly drivers to ensure that the method could be adapted to drivers of all ages, including the elderly. The results showed that the vibration from the back of the seat promoted the response to the attention target. In addition, the response was significantly faster when the vibration was presented from the same direction as the emerging attentional target.

Development of a Cochlear-Mimicking MEMS Sensor to Measure Auditory Stimulation in a Car

Riku Ito (Gunma University)･Kou Sasaki･Hiroyoshi Inaba (SUBARU)･Tetsuji Koyama (Gunma University)･Toshihiko Kozai (SUBARU / Gunma University)･Sinyoung Lee (University of Yamanashi)･Takuji Koike (The University of Electro-Communications)･Yuya Tanaka (Gunma University)･Tsutomu Iwase (SUBARU / Gunma University)･Takaaki Suzuki (Gunma University)

Human feeling still is not clear during the driving a car. In this reserch, we propose a cochelear-mimicking MEMS (Micro Electro Mechanical Systems) sensor to quantify the sense of reality that drivers feel with their ears to collect data for remote driving. The response of the proposed MEMS sensor was evaluated under both air and bone conduction inputs cased by automobile vibration.

Driver State Estimation from Automotive Operation Signals based on Pre-training using Vector Quantized Variational Autoencoders

Kenshiro Hanai･Yoshihiko Nankaku (Nagoya Institute of Technology)･Atsunobu Kaminuma (International Professional University of Technology in Tokyo / Nissan Motor)

This study aims to build a driver state estimator for in-vehicle services. The training of the estimator requires automotive operation signals and driver state labels, however the state labeling requires manual work. Therefore, we propose a framework in which a pre-training model is learned from a large amount of automotive operation signals and the estimator is trained using a small amount of labeled data.

Analysis, Modeling, and Control of Merging Behavior at Low Speeds

Tatsuya Ishiguro･Hiroyuki Okuda (Nagoya University)･Kenta Tominaga (Mitsubishi Electric)･Tatsuya Suzuki (Nagoya University)

In a merging environment where automatic and manual operations are mixed, it is important for both parties to communicate with each other. While much research has been conducted at high speeds, such as on expressways, little progress has been made at low speeds, such as on ordinary roads. In this presentation, we will experimentally observe the driving characteristics of drivers in right-angle merging at low speeds, and construct a right-angle merging model that takes negotiation into account.

Dynamic Estimation of Driver Model Parameters for Precise Reproduction of Driving Behavior

Ryuya Seki･Hironori Suzuki (Toyo University)

To elucidate the mechanisms of traffic accidents, it is necessary to estimate the driver's characteristics and appropriately select parameters according to the situation, ensuring an accurate reproduction of the driver's behavior. This paper aims to precisely estimate driving characteristics represented by driver model parameters based on measurements of headway distance, velocity, and relative speed to the preceding vehicle. Using a dual particle filter, we perform online estimation of the driver model parameters and convert these parameters into probability density functions. We then validate whether the parameters selected from this probability density function during simulations can accurately reproduce the driver’s behavior.

Research on Low Arousal Detection Systems with LSTM Models

Xupeng Zhou･Shuncong Shen･Toshiya Hirose (Shibaura Institute of Technology)

This study aimed to construct a Long Short-Term Memory (LSTM) model of a driver's arousal state during autonomous driving based on EEG using eye features. In the experiment, a driving simulator, eye movement meter, and electroencephalograph were used to measure eye features, in a late-night highway autonomous driving scenario. In addition, EEG data also measured band power for different frequency bands. Using the measured data, LSTM models were constructed for individual drivers, and their accuracy quantitatively evaluated by comparing the EEG output results of the constructed models with actual EEG data.

Effect of Oil Film Distribution in the Concave Created by Piston Skirt Profile or Pattern Coating on Skirt Friction Loss

Takuro Nakagawa･Kenta Sato･Hisanobu Kawashima･Hidekazu Suzuki･Tsuneaki Ishima (Gunma University)

The friction reduction effect of concavities created by piston skirt profile or pattern coating on the piston skirt was investigated. Based on the results of oil film visualization, calculations were carried out assuming that there was insufficient quantity of oil in the concavities. Friction loss increased when there was no oil in the concavities. It was found that when there was oil in a part of the concavities, the friction loss was lower compared with the condition where the concavities was completely filled with oil.

MBD Tool Development for Piston Ring Performance Prediction
-1D-CAE Model for Lubricating Oil Consumption-

Hikaru Chiba･Kazuya Mochizuki･Itsuro Suzuki･Masaru Yazawa･Naoki Iijima (RIKEN/NPR-RIKEN)

MBD (Model Based Development) tool was developed to reduce engine development costs. It is enable to predict oil consumption, blow-by, and friction force on various piston ring specification. In particular, oil consumption simulation were applied statistical methods and experimental coefficients obtained by oil visualization in glass cylinder. As a result, 1D-CAE model for oil consumption was generated. The characteristics are to predict quickly with higher accuracy. In this paper, effectivity of the model is shown by verification on various test condition.

Effect of Engine Oil Containing Nanobubbles by Ultrafine Pore Method on Reduction of Friction Loss in Piston System
-Correlation between the Generation Density of Nanobubbles and Friction Reduction Effect-

Kai Horiba･Masaya Fukuda･Shusuke Hoshino･Takumi Iwata･Masakuni Oikawa･Yuji Mihara (Tokyo City University)

The effect of nanoscale bubbles generated in engine oil by the ultrafine-pore method on friction work between piston and cylinder was investigated by measuring friction force in a floating liner engine. In this study, the correlation between the bubble generation density and the friction reduction effect was confirmed, especially by changing the surface area of the generating part of the nanobubble generator.

Development of an Evaluation Method that can Quantify the Effect of Fuels and Lubricants on Gasoline Engines

Shouta Tobe･Masami Shiki･Akihiro Suzuki･Naoki Eguchi･Kohei Hashimoto (SUBARU)

There are multiple methods for evaluating carbon deposits that simulate the environment inside the engine. However, it is not possible to quantitatively compare all the environmental effects used by the engine.　Therefore, in this study, we development a method to quantitatively evaluate the degree of impact of fuel and lubricant by simulating the usage environment.

Strategies for Application-Specific Fuel Economy Engine Oil Solutions

Field Sam･Anderson William B.･Engelman Kristi･Bell Ian･Hidetaka Hoshino (Afton Chemical)

This paper analyses the real-world operation of a common North American engine platform through chassis-dyno testing and compares it with the output of a simulation-based digital twin. The results from the chassis-dyno evaluation are then compared with industry-standard fuel economy test methods, evaluating their relevance for inclusion in fuel economy-driven engine oil specifications, particularly in the context of hybrid powertrains.

Estimating Exhaust Gas Emissions and Greenhouse Gas Emissions for the Medium and Long-term to Enhance Exhaust Gas Emission Regulations

Shuichi Kanari･Hiroshi Hirai･Akiyoshi Ito･Tetsuya Suzuki (JARI)

EU has decided to introduce the latest emission regulation, Euro 7, and Euro7 may lead to stricter exhaust gas emission regulations in Japan. The authors have developed a method for estimating long-term CO2 emissions from the automobile sector, which could estimate of exhaust gas emissions. The authors tried to estimate exhaust gas emissions when exhaust gas emissions regulations are tightened and traffic flow measures are implemented.

A Framework for Determining Characteristic and Difficult Sub-Samples of Real Driving Data for Model-Based Engine Emissions Optimisation

Jack Prior (Loughborough University)･Luke Bates (HORIBA Mira)･Byron Mason (RMIT University)･James Knowles (Loughborough University)

Robust multi-objective approaches to engine emissions optimisation have recently emerged that use data-driven models trained on representative driving data. However, this data collection is resource expensive, due to the range of conditions that may be represented. Two possible approaches to reducing this real driving data include selecting characteristic sequences that broadly represent driving behaviour and difficult sequences that contribute strongly to an objective function such as emissions. In this work, an analysis approach is devised that quantifies these two qualities and assesses their trade-off within several one-hundred minute cycles of RDE-representative data.

Closed-coupled SCR System Design using MBD (Model Based Development)

Hiroshi Anoda (Isuzu Motors)･Kasumi Yoneyama･Kenji Fujii･Chihiro Ohtsuka (Isuzu Advanced Engineering Center)･Takurou Iwashita･Tomotaka Kariya･Tatsuyuki Mochizuki (Isuzu Motors)

In the future, emission regulations are scheduled to be tightened, and it is expected that the aftertreatment system including control will become more sophisticated and complex. Therefore, the problem is how to reduce the engine bench test. This paper reports a case in which the design of the closed-coupled SCR system was carried out by MBD including controllability, and the verification at the engine bench test was drastically reduced.

Research on On-board CO₂ Capture Technology (1st Report)
-Measurement and Modeling of CO₂ Adsorption Characteristics-

Toshiaki Sakima･Hirotsugu Matsuda･Masahiro Horikoshi･Yasuhiro Matsumura･Junya Murata･Kenji Uchida･Yuji Harada (Mazda)

A technology that captures CO2 in engine exhaust gas has been studied. From the viewpoint of efficient development, it is useful to consider a CO2 capture system using models. Therefore, based on the experimental results of CO2 adsorption characteristics, the model accounting for external film diffusion and intraparticle diffusion was considered. As a result, the adsorption rate model that can reproduce the experimental CO2 breakthrough curves was established.

Research on On-board CO₂ Capture Technology (2nd Report)
-Model-based System Design and its Verification-

Hirotsugu Matsuda･Ryo Yamamoto･Masahiro Horikoshi･Yoshihisa Nou･Toshiaki Sakima･Kenji Uchida･Yuji Harada (Mazda)

A system that can continuously capture CO2 in engine exhaust gas under the on-board constraints has been investigated. The feasibility study was carried out using 1D-CFD tools and real-scale experiments using actual exhaust gas. The results showed that the potential of about 90% of CO2 capture rate was confirmed in the range of engine power for urban driving.

A Study on the Mechanism of Transient Reaction and Purification Performance Improvement of Three-way Catalysts with High Frequency Perturbation

Masato Terasawa･Yuta Sugaya･Koki Umemoto･Jin Kusaka (Waseda University)

A 2.5L gasoline engine was used to investigate the amplitude and frequency effects of perturbations caused by fast switching of air/fuel ratios on purification characteristics. Pd/Al was used as the test catalyst. The results showed that the purification rates of NO, CO, and THC were improved by increasing frequency and decreasing amplitude, with NO and CO having higher sensitivity to frequency.

Gasoline Particulate Filter for Tier4 Regulation

Ryuta Takai･Takashi Aoki･Tasuku Matsumoto･Yuji Sasaki･Kiwamu Sugiura･Yuichi Hamazaki･Masaki Ito (NGK INSULATORS)

Tier 4 regulations in the United States tighten the PM (Particle Mass) regulation value to 0.5 mg/mile. Only improving engine control is not enough to meet Tier 4 regulations, and it is expected that gasoline-powered vehicles in the United States will be required to be equipped with GPF. In order to consider a suitable GPF for Tier 4 regulations, NGK has evaluated the filtration performance of GPFs under conditions including the newly regulated cold conditions. This paper presents the evaluation results and suitable GPF for Tier 4.

Leveraging DOConFilter to Improve Exhaust System Packaging

Shiori Shiraki･Takashi Kinoshita･Yohei Mitsui･Tsuyoshi Asako･Katsunori Tanaka･Tasuku Matsumoto･Takashi Aoki (NGK Insulators)

Tightening of PM/PN and NOx emission regulations worldwide increase complexity of aftertreatment system. Due to limited space, DOConFilter, which bundles DOC function into DPF, attracts attention from Off-highway OEMs as a downsizing solution. DOConFilter can effectively replace DOC + catalyzed DPF or DOC + uncatalyzed DPF systems. On the other hand, downsides of DOConDPF are increase of pressure drop and mediocre regeneration efficiency due to combined washcoat on DPF.
This presentation reports the development of DOConFilter, which aims to improve pressure drop and regeneration efficiency by combination of high filtration material and high cell density.

Development of a Method for Measuring CO₂ Concentration in Amine-based Solvents using Fluorescent Dyes

Shohei Tomita･Michihiko Yamamoto･Masaki Nishikawa (Aisin)･Yasuhiro Egami･Yui Kiyota (Aichi Institute of Technology)

Efforts are underway in the automotive industry to develop devices for capturing and recovering CO2 emissions from factories in order to achieve carbon neutrality. In this report, we introduce a technology that has been established to visualize the CO2 concentration distribution in a solution using an optical method with fluorescent dyes in a system that separates and recovers CO2 from exhaust gases using the amine scrubbing method.

Consideration on Understanding the NOx Purification Performance of Urea SCR Catalyst Installed in Heavy-duty Vehicles during the Use Process

Toshiro Yamamoto (NALTEC)

Data on the NOx purification performance of copper-based zeolite SCR catalysts installed in vehicles that comply with the 2016 exhaust gas regulations was collected continuously by conducting chassis dynamometer tests and actual road driving tests as the accumulated mileage increased. Using these, the NOx purification rate, space velocity, etc. were used as analytical indices to consider the NOx purification performance of the urea SCR catalyst during the use process. As a result, when the NOx purification performance of the urea SCR catalyst decreases during use, it was found that the NOx purification rate decreased significantly as the space velocity increases.

A State-of-the-art Soot Filtration Model of a Particulate Filter: Application to an Estimation of a Particle Emission Downstream of the Filter

Kazuki Nakamura (Waseda University)･Anton Nahtigal (AVL-AST d.o.o. Slovenia)･Kyohei Yamaguchi (Kokushikan University)･Jin Kusaka (Waseda University)

The Euro 7 emission standard further tightens a particle emission. It requires developments of emission control systems and simulations with improved accuracy are inevitable. In this study, the extension of a simulation model is considered by linear filtration efficiency of particles by cake layers in accordance with its thickness and a persistent slip of particles inside walls independent on accumulation of the particles. The entire behavior of particle emission calculated by the model was in a good agreement with experimental data which were obtained with miniature gasoline particulate filter samples and a synthetic particle generator.

Investigation of Self-localization using Side Camera

Yoshiki Sakadani･Toshihiko Hashiba･Masaya Endo (Mitsubishi Electric)

When locating a vehicle's position on a High-definition map, if the accuracy of GNSS decreases, there is a method to locate the vehicle's position by obtaining the lane shape with onboard sensors. However, there are scenes where it is difficult to locate the vehicle's position because the lane shape cannot be obtained with sensors depending on the road environment. In such scenes, we considered a method to estimate the lane shape and enable the location of the vehicle's position.

Technological Development and Establishment of Simulation Environment for Lane Merging Support

Nobuhiro Araki･Kenta Shintoku (Kozo Keikaku Engineering)･Koichi Miyashita･Satomi Aiko (Mitsubishi Research Institute)

This study evaluated the improvement and feasibility of merging processes using the traffic flow simulation environment with two merging assistant systems through the infrastructure: Day 2 system which continuously acquire information on the main lane and provide to the vehicle on the merging lane, and Day 3 system which coordinate gaps between vehicles on the main lane. Result showed that the Day 2 system effectively improved merging and met feasibility criteria. While the Day 3 system is also effective, but the additional support in the Day 3 system did not show significant improvement with the parameters adopted in this study.

Analysis of the Effect of Road Alignment on Visibility Delay for Curved Roads

Hiroshi Kuniyuki･Seiya Tanaka･Fumitaka Fukuzawa (Suwa University of Science)･Masashi Makita (Teikyo University)

This study analyzed the effects of road alignment on visibility delay for curves by experiments using a driving simulator. The results showed that the visibility behavior for curves was first recognition of the existence of the curve, followed by recognition of the curvature of the curve. Furthermore, it was found that the curve visibility delay in those phases was influenced by the left-right difference and the curvature difference.

Proposal of Virtual Platform by Utilizing Multi-agent Traffic Simulation for Sophisticated Automated Driving System Development

Sou Kitajima･Nobuyuki Uchida (JARI)･Naoki Suganuma (Kanazawa University)･Tadashi Okuno (OS Planning)･Jun Tajima (Misaki Design)

This paper describes an effective virtual platform to develop more sophisticated Automated Driving System by generating both complicated and perplexing scenarios. Because it is difficult to find and accumulate these scenarios through field operational test, an enhanced function is developed and implemented our multi agent traffic simulation. The results indicates that this function enable not only to reinforce significant variation of extracted rare scenarios but also to realize decision making improvement of Automated Driving System.

Effect of Difference in Oxygen Storage State of Pd/CeO₂-ZrO₂ Three-Way Catalyst on Oxygen Storage Distribution

Yuki Watanabe･Yuma Hayashi･Tsuyoshi Nagasawa･Susumu Sato･Hidenori Kosaka (Institute of Science Tokyo)･Hiroyuki Itoyama･Chengwei Huang (Nissan Motor)

In order to clarify the oxygen storage and release mechanism of three-way catalysts (TWC), visualization experiments of the oxygen storage distribution were conducted using isotope quench technique. In this technique, oxygen isotope labeling, and reaction quenching are conducted, then isotope distribution is measured by secondary-ion mass spectrometry. In this report, visualization experiments were conducted using a model catalyst consisting of dense ceria-zirconia disk and Pd to clarify the effect of the difference in oxygen release/storage states on the oxygen storage distribution by changing the hydrogen reduction time and oxygen storage time.

The Effect of Stored Oxygen on Purification Performance of Three-way Catalysts under Perturbation Condition

Sota Aoyama･Jin Kusaka (Waseda University)

The effect of oxygen storage capacity on the purification performance of three-way catalysts was experimentally analyzed by conducting tests incorporating perturbations using catalysts with oxygen storage capacity. In the test results, the purification performance characteristics with and without catalyst degradation were clarified by focusing on the decrease in purification rate for each gas type and the change in oxygen concentration at the inlet and outlet.

Verification of Temporary Poisoning Mechanism in Automotive Catalysts by HC Components

Hiroyuki Minokoshi･Daichi Tabuchi･Ryo Nagai (SUBARU)･Masaaki Haneda (Nagoya Institute of Technology)

Performance of automotive catalysts temporarily deteriorates after HC components in exhaust gas attach to the catalysts. We studied HC type and attachment site to the catalysts to verify the mechanism of temporary poisoning. As a result, we found that exhaust gas contained a high proportion of specific types of aromatic HC. In addition, we found that catalytic performance deteriorated after these types of aromatic HC attached to the boundaries between platinum group metals and CZ materials.

Study of an Exhaust System for 100% Electric Drive Hybrid Vehicles that Achieves Well-to-wheel Exhaust Emissions Comparable to Electric Vehicles
-The Challenge Towards Zero Emissions-

Akira Inoue･Hiroyuki Itoyama･Atsushi Morohoshi･Jin Yokoyama (Nissan Motor)

Internal combustion engines for electric hybrid vehicles are required to respond to stricter emission regulations, CO2 reduction, and fluctuations in material markets.
The advantages and disadvantages of catalyst warm-up were examined in multiple systems, and the possibility of achieving electric vehicle-level exhaust emissions (WTW), reducing CO2 , and the amount of precious metals in the catalyst was examined through both simulations and experiments for ceramic EHC, which has high compatibility with 100% electric drive hybrid systems.

Effect of Supercharging on Ammonia/Gasoline Co-combustion Characteristics in a High Compression Ratio Engine with Sub-chamber

Takanobu Okada･Hikaru Yamamoto･Hikaru Shiraishi･Emir Yilmaz･Mitsuhisa Ichiyanagi･Takashi Suzuki (Sophia University)

Ammonia has gained attention as a carbon-free fuel. With its high energy density and good transportability, ammonia is expected to be used as an engine fuel. However, ammonia faces challenges such as high auto-ignition temperature and slow combustion. To identify stability combustion factors, this study examined the limits of ammonia content in the fuel and the effect of supercharging. Using gasoline as supplementary fuel and varying the ammonia ratio, stable operation was achieved with ammonia energy share of 77%, in addition supercharging improved maximum in-cylinder pressure and performance.

Evaluation of Combustion Performance of Emulsion Fuel using Time-series Analysis of Cylinder Pressure

Keisuke Yagi･Iman Kasih Telaumbanua･Yoshihiko Oishi･Hideki Kawai (Muroran Institute of Technology)･Himsar Ambarita (Universitas Sumatera Utara)

In emulsion fuel, which is one of the candidates to achieve carbon neutral, increasing water content causes uneven burning. The purpose of this study is to evaluate the combustion performance of emulsion fuel containing different water content by analyzing the time series cylinder pressure data using FFT. The spectrum obtained from the analysis can show instantaneous changes in cylinder pressure during emulsion and can be a criterion for judging normal or abnormal combustion.

A Study on Combustion Characteristics of Ammonia-diesel Dual Fuel Engine

Yuma Hozen (Waseda University)･Ryosuke Kogure･Takafumi Tanaka (Mitsubishi Heavy Industries Engine & Turbocharger)･Tomohiro Koga (Mitsubishi Heavy Industries)･Toma Erikawa･Jin Kusaka (Waseda University)

To investigate the combustion characteristics of ammonia mixed diesel fuel, visualization experiments were conducted using a rapid compression and expansion system. A model of the reaction and combustion was constructed, and the effects of changes in operating conditions were investigated. The results showed that ammonia co-firing increases N2O, but reduces greenhouse gas emissions by about 40% at a co-firing rate of 60%.

Study on Compliance with Fuel Standards for FT Synthetic Gasoline and FT Synthetic Diesel Oil

Kenichi Okamoto･Noriaki Ohmori･Hiroshi Kisai･Mitsunori Tabata (Japan Petroleum and Carbon Neutral Fuels Energy Center)･Takeru Ohtsuka･Natsuki Hamada･Kazuhito Sato (Cosmo Oil)

We confirmed the Alignment of prototype FT gasoline and prototype FT diesel oil with fuel standards, which were produced by appropriate post-processing of FT crude oil, and grasped the characteristics of their fuel quality. Additionally, we verified the removal effect of by-products such as oxygen-containing compounds through post-processing. Furthermore, we understood the characteristics of energy efficiency and liquid fuel yield during the post-processing of FT crude oil.

The Impact on Rubber Components of Oxygenated Synthetic Fuels and Prototype FT Synthetic Fuels

Noriaki Ohmori･Kenichi Okamoto･Hiroshi Kisai･Mitsunori Tabata (Japan Petroleum and Carbon Neutral Fuels Energy Center)･Takeru Ohtsuka (Cosmo Oil)

In the world, research and development on synthetic fuels towards carbon neutrality is being conducted.
Therefore, we evaluated the impact of the prototype FT synthetic gasoline and FT synthetic diesel fuel, as well as oxygen-containing synthetic fuels, on rubber materials. The results are shown below:
The prototype FT synthetic gasoline and FT synthetic diesel fuel had minimal impact at the evaluated blending ratios.
We confirmed that oxygen-containing synthetic fuels may have an impact on rubber materials even at low blending ratios.
Based on these, we organized considerations for use in automobiles.

Analysis of Transmission Efficiency and Transient Dynamics in Rubber V-belt Continuously Variable Transmission

Ryota Yamori･Tatsuhito Aihara (Hosei University)･Yutaka Kimoto (Exedy)

For the purpose of predicting the transmission efficiency during operation of a rubber belt-type CVT for motorcycles, including gear shifting, we developed theoretical equations. Conventional studies have often dealt with the theorization of constant speed states, and it has been difficult to predict the transmission efficiency because a theoretical analysis method for the behavior during gear shifting has not been established. We compared the results of calculations based on the developed theoretical equations with experimental results, demonstrating their effectiveness.

Development of Light-weight Final Drive for New Full-size SUV

Shiro Kono･Shin Hashimoto･Hiroaki Katase･Takayuki Asai･Masakatsu Koide･Kanta Fukumoto (Nissan Motor)

We developed a new final drive unit for a new full-size SUV. It consists of a high-efficiency and class-leading light-weight aluminum carrier. To address concerns about reduced rigidity due to aluminum, we applied snap rings to fix the differential side bearings, ensuring the same gear support rigidity as conventional cast iron housings. By adopting a low-offset hypoid gear and low-viscosity oil, and optimizing the housing shape for efficient heat dissipation, we achieved a compact design. Applying this new unit to an independent suspension axle enables premium-class ride comfort and quietness, with a towing capacity of 8,500 lbs and high fuel efficiency.

Flow Analysis of Lubricating Oil in a Rotating Environment

Hiroto Hayashi･Takuma Kato (Chiba Institute of Technology)

This study focuses on shaft core lubrication, the method of oil supply within the transmission, and examines it from the perspective of computational fluid dynamics (CFD) using the finite volume method. By altering the analysis conditions, changes in fluid behavior became evident, leading to variations in lubrication. The study aims to clarify the relationship with factors such as rotational speed, lubricant properties, and shape, with the goal of improving technology.

Flow-rate Characteristics of Lubricating Oil Flow around Discharge Hole in Rotating Shaft

Takuma Kato (Chiba Institute of Technology)

In delivering lubrication through a shaft of an automatic transmission, it is difficult to lubricate due to the effects of centrifugal force and agitation caused by rotation. To solve this problem, we investigated the behavior of gas-liquid two-phase flow in a rotating pipe. Through measurement of the flow rate and flow visualization, we designed the shape of the discharge hole to suppress the rotation speed sensitivity.

The Influence of Lubricant Friction Properties on the Efficiency of Electric Transaxle

Hiroyuki Tatsumi･Takashi Yanagihara･Yuki Okada･Keiichi Narita (Idemitsu Kosan)

The effect of friction characteristics of lubricants on the efficiency of transaxle for electric vehicles was investigated. Evaluation using a high-speed gear testing machine and an actual reduction gear revealed that the reduction of traction coefficient contributes most to efficiency improvement, and that friction properties in boundary and mixed lubrication are also effective in improving efficiency.

Auxiliary Brake Apparatus by Air Compression and Release for Stop of Heavy FCV Regenerative Brake (4th Report)
-Side Clearance Seal and Exhaust Air Reuse System for Supercharged Intake Air Adoption-

Chinatsu Sano･Daisuke Maeyama･Toshinori Fujita･Takashi Shibayama (Tokyo Denki University)

A simple structure auxiliary brake by utilizing air compression and release cycle had been proposed in last three reports to prepare for the case of FCV truck regenerative brake failure . In this report, two important challenges towards practical application for the new brake will be reported. The one is exhaust air reuse system for obtaining super charged inlet air to reduce external compressor capacity. And the other is abolition of O-ring to increase reliability by replacing side clearance seal function between piston and cylinder side surface. The test result will be reported.

Study of Abnormality Detection Method using Dual Motor System for EV
-Detection of Motor Torque Decrease by Planetary Gears-

Makoto Kusakabe･Teruhiko Nakazawa･Yasumitsu Osada･Haruhiro Hattori (Toyota Central R&D Labs.)

We propose an anomaly detection method for an EV drive system that combines the power of two motors using a planetary gear.
This system has cooperative control that uses the output torque and the rotational speed difference between the two motors as target values.
We devised a method to detect an anomaly accompanied by a decrease in the torque of one motor from this control variable change.
We conducted a test on an actual machine and confirmed that it is possible to accurately detect the decrease in torque due to a rise in rotor temperature.

Effect of Power Source and Transmission Mechanism on WLTC Electric Consumption of BEV

Yasuo Moriyosihi (Sustainable Engine Research Center / Chiba University)･Minoru Ohno･Mutsumi Mizushima･Tatsuya Kuboyama (Chiba University)

The study of changing combination of motor/generator and gearbox is actively conducted to improve the specific electric consumption of BEV. In this study, OpenModelica model provided by TRAMI was used to predict the specific electric consumption in both steady run and WLTC cycle. As a result, it was quantitatively found that i) WLTC ranking does not necessarily accord with steady one, ii) the ring gear output is good when using planetary gear system and iii) a combination of 2 motor and multi-speed is the best in specific electric consumption.

Realizing Shift Control Adaptation through Transmission-iLS

Daiki Sato･Kohei Dodo･Kenichiro Tsukamoto･Daisuke Kogure･Kazuya Arakawa (Toyota Motor)

Shift control adaptation for powertrains is crucial for capturing vehicle transient behavior, and it often relies on actual vehicle evaluations. To improve development efficiency through early completion, we developed a Hardware-in-the-Loop facility utilizing physical models and high-response dynamometers to replicate gear shift behavior, enabling shift control adaptation without actual vehicle and engine. We also showcase an example where the gear shift performance is predicted using the simulation model that incorporates the obtained results.

Mechanism Analysis of Vehicle Dynamics using Front Wheel Speed-up System for AWD

Akira Ono･Tomohiro Shimizu･Susumu Ito･Yusuke Kakihara･Masami Oguri･Yoshinobu Yamazaki･Yusuke Yabusaki･Hirofumi Kawarazaki･Ryouji Aoki (SUBARU)

The effect of restraining rotation ratio between front and rear wheels for all wheel drive vehicle is well known as improving vehicle dynamics in cornering situation according to previous research.
This paper describes that mechanism analysis of torque transfer phenomena between front and rear axle through the propeller shaft and effect of the vehicle dynamics on the snowy road with the front wheel speed-up system.

The Effect of Video Viewing before Driving on Driving Behavior: Analysis of Drivers with Different Levels of Trait Anxiety

Chihiro Shumiya･Yukiko Nishizaki (Kyoto Institute of Technology)

Video contents influences emotions or post-viewing behavior. However few studies have examined the effects of watching videos before driving. Negative videos, in particular, may adversely affect drivers with high trait anxiety. This study experimentally examined the impact of qualitatively different video content on subsequent driving behavior and its association with individual differences in trait anxiety.

Evaluation of Driver Trust in in-Vehicle Driving Assistance Information Across Various Situations using Physiological Data

Jongseong Gwak (Takushoku University)･Hiroshi Yoshitake･Motoki Shino (Tokyo Institute of Technology)

To quantitatively evaluate driver trust in the provided information for driving assistance, we tested the potential use of physiological data. Central nervous system responses to appropriate and inappropriate information were investigated using a driving simulator and physiological measurements. By analyzing event-related potentials (ERPs) under each condition, we found differences in the characteristics of late components of the ERPs. This indicates that physiological data can be useful for assessing driver trust in various driving assistance information.

Evaluation of Effect of the Roll Component of Shaking on the Operability of Information Terminals

Yusuke Yasuki (SOKEN)･Shunitsu Kubo (DENSO)

With the spread of AD and ADAS, improving comfort during the second task is also an important issue. In this study, operability of a tablet device was evaluated from body behavior, eye movement, and stress indices when operating the tablet on a ride comfort evaluation test device that can reproduce the driving waveform of a passenger car. As a result, it was clarified that the roll component of shaking has a large contribution to the deterioration of operability.

The Development of a Integration Method for Hollow Rotor Shafts by Warm Flow Forming

Naoto Taguchi･Tomoyoshi Naganawa (Nissan Motor)･Koji Higaki･Takuya Yamazaki (Nihon Spindle Manufacturing)

Various types of motors are used in electric vehicles, but in order to operate the motor in a higher efficiency state, measures for higher rotation are required. In addition, since high temperature is generated when the rotor-shaft is operated at high rotation, there is a need to provide a cooling structure in the rotor shaft. This paper reports an example of application development of warm flow forming method to manufacture rotor shafts incorporating these requirements at lower cost.

Research on Cutting Conditions via Simulation by Bayesian Optimization

Hisao Eto･Yoshihiro Ohnishi･Takeo Miyaguchi (ITOCHU Techno-Solutions)

The cutting simulation has played the big role in the manufacturing field. Our group has been focusing on the modeling via Physics-Based Methods on CAD/CAM. In this presentation many cutting tests are done by the cutting simulations. Simulation results become like the big data so any knowledge about cutting process might be able to be found from such data. It is benefit that the many cases are done without actual tests by the simulation. However, this takes a long time. Therefore, we tried the Bayesian Optimization to consider the simulation results by not so big data.

Development of High-speed Prediction System using Surrogate Models for Magnet Wire Forming

Shintaro Nakano･Toshiki Terabe･Le Dinh Thanh (Toyota Motor)

This study presents a high-speed prediction system using surrogate models for coiled wire forming. First, we confirmed that CAE results coincide with the real. Next, we constructed the surrogate model using a Convolutional Neural Network (CNN) and CAE data taken from CAE results. The surrogate models can provide prediction on strain distribution within 10% error, while reduce computation time from days to seconds. It is highly expected that using such surrogate models, motor development period can be significantly shortened.

A Study on the Influence of Initial Tightening Force Variation in Calibrated Wrench Method

Soichi Hareyama･Ken-ichi Manabe･Satoshi Kobayashi (Tokyo Metropolitan University)

When tightening a large number of bolts, the torque coefficient or friction coefficient and tightening torque have a significant effect on the variation of the initial clamping force (initial axial tension). The coefficient of friction is affected by the lubrication conditions during tightening and the machining accuracy of the bolt and nut. The tightening torque is the product of the distance to the force point of the torque wrench and the force acting on it, and is considered to be a variable independent of the torque coefficient and other factors. Although there are many studies on the friction coefficient and torque coefficient, the variation of tightening torque has not been studied in detail. In this study, we first examine the effects of errors in the position of the force point and the direction of the force of the torque wrench and the tool itself on the tightening torque. Next, the influence on the variation of tightening torque based on the tightening operation, i.e., human error, is examined, in which a simple tightening test was performed by three workers. The results of the study and the variation of tightening torque based on the test results are organized as 90% confidence limits.

Effect of Panel Curvature and Thickness on Outer Panel Sink Mark by Mastic Adhesive

Takashi Iwama･Kentaro Sato･Yoichiro Ohnishi･Tsuyoshi Shiozaki (JFE Steel)･Keigo Unoki･Hiroki Toriyama･Takafumi Watanabe･Kenichi Matsunaga (Toyota Motor Kyushu)

When the mastic hardens and shrinks during the painting process, sink mark caused by the retraction of the outer panel becomes an issue. Panel thickness is known to be a factor that affects sink mark, but the influence of design curvature has not been clarified.
The influence of design curvature on sink mark was investigated by experiments using a laboratory model and CAE. It became clear that the effect of design curvature on distortion was greater than that of panel thickness.

Analysis on Influence of Deceleration Generated by Adaptive Cruise Control on Driver Forward Collision Accident-avoidance Behavior

Norika Arai･Shounosuke Tsujiide･Yohei Fujinami･Raksincharoensak Pongsathorn (Tokyo University of Agriculture and Technology)･Fumio Sugaya･Toshinori Okita･Shintaro Inoue･Masaaki Uechi (Toyota Motor)

Adaptive Cruise Control （ACC） is designed for enhancing driving convenience. It is reported that the use of ACC reduces the collision rate on highways even though drivers who overtrust the system conduct secondary task during driving. This paper describes the analysis on the influence of deceleration generated by ACC on the driver avoidance maneuver and the collision risk reduction effect in the driving situation that drivers are conducting secondary task.

Experimental Study about Avoidance Behavior of the Driver who Meets with the Dangerous Scenes during City Driving (The 2nd Report)

Toru Kojima･Yuki Manabe･Koichi Kitada･Kenji Morizaki (NALTEC)･Seitaro Fukuda･Tadahumi Shima (MLIT)･Yukihiro Ikeda (Toyota Motor)

In order to study the relation of safety level between automated driving vehicle and human driver, analysis of driving behavior of human drivers is necessary. In this research, the experimental test by using the driving simulator was conducted in some dangerous traffic scenes, which were selected from the accident patterns assumed to occur in the root where the automated driving demonstration on the public road and mixture traffic with other traffic participants were planned.

Investigation on Prediction Method of Traffic Participant Darting-out Velocity from Blind Spot Considering Traffic Environment Context

Ryuki Ota･Aki Tanikawa･Pongsathorn Raksincharoensak･Masao Nagai･Yohei Fujinami (Tokyo University of Agriculture and Technology)･Takaya Yamazaki･Minoru Higuchi (Honda R&D)

This study proposes a model for estimating the dynamic behavior of darting-out objects in a poor visibility driving environment in order to develop an advanced driver assistance system (ADAS) that aims to reduce the number of collision accidents on urban roads.
Based on real driving data, we modeled the relationship between the traffic environment context and the dynamic behavior of darting-out objects employing probabilistic theory. This approach indicated the possibility of estimating the characteristics of the darting-out objects.

An Analysis of Lateral Distance between Four Wheeled Vehicles and Overtaking Motorcycles in ASEAN Region

Hisashi Imanaga･Hiroki Kawashima (JARI)･Takashi Hasegawa･Hiroyuki Mae (JAMA)

This study analyzes lateral distance between four wheeled vehicles (cars) and overtaking motorcycles in Thai and Malaysian highway. It was confirmed that most motorcycles drive around white both lines of car driving lanes, and the frequency decreases with lateral distance from car. In addition, the form of distribution changes depending on car travelling speed (the peak is shifting to far side if driving speed increasing).

Development of End-of-Life Vehicle Chassis Number Reading Software using AI-OCR

Masayoshi Nakamura (Fukuyama University)･Shigeya Ikebo (Nagoya Bunri University)･Satoru Yaseda･Hitoshi Yamasaki (Aratani Shoukai)

In order to comply with the resource recovery incentive system scheduled to be implemented from 2026, we developed VIN number reading software using AI-OCR with the aim of accurately managing ELVs and removed parts. After reading the VIN numbers of approximately 1,000 vehicles, it became clear that VIN numbers were not standardized in Japan, and the number of digits and type of plates varied depending on the manufacturer, making them difficult to read. Furthermore, based on the results, we considered ways to further improve the accuracy of the software.

Recyclability of Lithium Recovered from Used Lithium-ion Batteries

Hikari Kuroda (MITSUBISHI MOTORS)･Shohei Yoshida (DOWA ECO-SYSTEM)･Mikihiro Takahashi (Central Glass)･Noriaki Masuda (GS Yuasa International)

Battery closed loop recycling will be indispensable in the future, because there is a concern of the shortage of battery resources and the increasingly stringent regulations on recycling.
In this paper, the performance of battery using electrolyte solution with lithium extracted from used lithium-ion batteries is reported.

A Circular Economy Indicator for Vehicles
-Evaluation of Vehicles for Sustainable Society-

Takamichi Iwata (Toyota Central R&D Labs.)･Takamichi Ueda･Yoshiro Masuda (Toyota Motor)･Kiyotaka Tahara･Mitsutaka Matsumoto (AIST)･Masashi Hara･Tetsuro Kobayashi･Daisuke Yamada･Hisaaki Takao (Toyota Central R&D Labs.)･Eiji Ishida･Mitsuru Ogasawara･Takayuki Nagai (Toyota Motor)

In order to realize a circular economy for automobiles, it is considered necessary to develop a strategy based on an evaluation that includes resource recycling and economic efficiency, in addition to CO2 emissions. In this study, we devised an evaluation index for automobiles that takes into account recycling and the economic costs on users.