Investigation of the Effect of Automotive Tire Tread Patterns on Vehicle Aerodynamic Drag

Shingo Ida･Masahiro Nagase (Sumitomo Rubber Industries)･Satoru Yamada･Ikuo Tanaka (Dassault Systems)

To reduce vehicle running resistance, the effect of differences in tire tread patterns on aerodynamic drag was investigated. Using two types of vehicles for CFD analysis, it was found that variations in tread patterns can change the tire drag contribution (CD) by up to 0.003 for all four tires combined. Additionally, differences in tread patterns were found to influence the flow field behind the vehicle.

Investigation of an Index for Evaluating The Aerodynamic Drag Reduction Effect of Full Wheel Covers

Mitsuharu Takeda (Suzuki Motor)

In Kei cars, steel wheels combined with full wheel covers are commonly used, and the styling of the wheel covers has an influence on aerodynamic performance (ΔCd). In this study, a simple index based on the opening configuration in a specified region near the inner side of the wheel cover outer edge is proposed. A clear correlation between the proposed index and ΔCd was confirmed, indicating that the proposed index has potential as an aerodynamic evaluation metric in the styling design stage.

Analysis Method for Airflow around a Vehicle Considering Electrostatic Charging, Surface Ion Neutralization, and Electrostatic Force Fluctuation by Vehicle Motion

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

In the previous study, flow variations induced by vehicle electrostatic charging during driving were clarified through numerical analysis using a simplified step model that couples three physical fields: fluid flow, electrostatics, and charge transport. In this study, variations in tire-induced charge input, ambient positive air ions, and surface neutralization were further considered, and the influence of each factor on the airflow was evaluated.

Construction of Online Co-Simulation Environment
-(7th report) Fundamental Investigation of MBD for OBD-

Kenichiro Ogata･Daijiro Nakamura･Takashi Tsurumaki (Honda R&D)･Michinori Tani (Honda Motor)･Toshiharu Fukushima･Yohei Okagawa･Yutaro Tanimoto･Takuya Honjo (Honda R&D)

A highly efficient power unit development process based on Model-Based Development (MBD) is essential to achieve timely mass production of automobiles. However, On-Board Diagnostics (OBD), which is one of the regulatory requirements for mass production, involves fault diagnosis of vehicle systems and therefore typically requires the use of actual vehicles in the later stages of development. As a result, a full transition to a highly efficient, model-based development process remains challenging. This study focuses on an evaporative leak diagnostic function of the fuel tank system under OBD regulations and investigates the applicability of MBD to this regulatory domain

Development of a Method for Predicting Ambient Temperature of In-Vehicle Electronic Components Using 3D Fluid Analysis
-(Second Report)-

Takafumi Okumura･Hisao Nishimori･Jun Muto･Taishi Kamatani･Yahiro Honda･Daiki Yamaguchi (Toyota Motor)

With the enhancement of functionalities in automotive electronic components and the diversification of vehicle designs and applications, the thermal design of electronic components based on their installation positions has become increasingly critical. To predict the temperature within the cabin, this paper applies the method proposed in our first report to a different vehicle model and region, and compares the results with measurements to validate the boundary conditions under which the method is effective and to improve errors in predicted temperature variations.