The Evolution of Power Unit Development Process through MBD (Sixth Report)
-Improving Fuel Efficiency through Drive Unit Thermal Management-

Takuya Honjo･Rika Kikuchi (Honda Motor)･Mikito Nagata (Meitec Fielders INC.)･Kenichiro Ogata･Keijiro Koide (Honda Motor)

To achieve a carbon-neutral society, improving the fuel efficiency of hybrid power units is essential. For further performance enhancement, the thermal flow of the drive unit needs to be properly designed. Using a 1D drive unit thermal model, the specifications for the thermal management system were clarified, considering the vehicle system performance.

The evolution of power unit development process through MBD (Seventh Report)
-Model acceleration through formulation technology for engine thermal plant models-

Keijiro Koide･Kenichiro Ogata･Takumi Matsumoto･Go Toshizane (Honda Motor)

To enhance vehicle performance through power unit optimization, a 1D engine thermal plant model incorporating design data was developed to satisfy system-level thermal requirements. However, performance verification requires simulating numerous driving scenarios and control calibrations, making computational speed a challenge. This paper introduces a new formulation technique that maintains the accuracy of conventional models and preserves engine component-level temperature prediction, while achieving faster-than-real-time computation. This enables efficient simulation and supports broader scenario coverage, contributing to more effective performance validation and calibration processes.

The Evolution of Power Unit Development Process through MBD (Eighth Report)
-Model construction integrating thermal plant models and its use for control calibration-

Kenichiro Ogata･Takuya Honjo･Rika Kikuchi･Keijiro Koide･Takumi Matsumoto･Go Toshizane (Honda Motor)･Junya Matsumoto (Ryomo Systems)･Mikinori Sato･Yuki Hamatsu (AutoTechnicJapan co., LTD.)･Mikito Nagata (Meitec Fielders INC.)

In order to enhance performance of hybrid power unit, utilization of MBD throughout entire development process is anticipated. While MBD enables development without relying on prototype in early phase, it requires significant resources for control calibration using vehicles during performance verification phase. Therefore, replacement by MBD is necessary. This report constructed integrated model that combined 1D drive unit thermal plant model and engine thermal plant model with a vehicle system model, and implemented virtual calibration with design variables as calibration settings. By conducting multi-objective function and multi-design variable calculations, it was possible to explore calibration settings that maximize performance potential.

The Evolution of Power Unit Development Process through MBD (Nine Report)
-Enhancing Robustness of Energy Management Control for Hybrid Power Units-

Takumi Matsumoto･Kenichiro Ogata･Yuichiro Murata･Yuki Honma･Keiji Tojo･Tetsuya Fukuoka (Honda Motor)･Junya Matsumoto (Ryomo Systems)･Mikinori Sato･Kazuma Inukai (AutoTechnicJapan co., LTD.)

In order to fulfill different customer needs, robust power unit performance that adapts to usage conditions is demanded. The conventional development for the power unit requires a heavy workload and long periods because of vehicle-based robustness verification. Therefore, improvements are necessary. This report focuses on improving development efficiency through MBD. Specific means are transitioning control models to ECU onboard logic and creating scenarios that cover market driving patterns using big data. Conducting robustness verification with combining these with vehicle 1-D system model, we achieved rapid development for the robust power unit performance.

Model-Based Development of Parallel Hybrid System for K-cars

Norifumi Mizushima (AIST)･Kyohei Yamaguchi (Kokushikan University)･Yoichi Iiyama･Yuji Kado (JAXA)

In the previous study, the authors explored the optimized engine geometrical parameters, such as bore and stroke, compression ratio, connecting rod length and intake valve timing, to improve thermal efficiency of K-car engine regardless of the engine displacement standard for K-cars. In this study, the vehicle simulation model and quality engineering tools were linked to investigate the specifications of a parallel hybrid system for K-cars by applying the results of the previous report. This report introduces the methodology of the study and proposes a hybrid system for K-cars that can achieve WLTC (hot) mode fuel economy of 40 km/L.

Study of optimal thermal and power management control for Hybrid Electric Vehicle based on vehicle system 1D simulation model (Second Report)

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

When using the lithium-ion battery in the electric vehicle, it is necessary to take measures against degradation at high temperatures and battery voltage drop at low temperatures. In order to achieve this objective, it is important to control the temperature and power of the battery in an appropriate and efficient manner. In this report, we studied how to manage lithium-ion batterie and thermal system in hybrid electric vehicles under conditions of battery temperature rise at low ambient temperature using a vehicle system 1D simulation model and optimization method.