Abstract: To improve the efficiency and accuracy of testing driving resistance in new energy light-duty vehicles, a comparative analysis of two wind speed measurement methods and their corresponding coasting test procedures is conducted in this study. The objective is to identify the most appropriate method for testing driving resistance under varying vehicle speed conditions. Experimental procedures specified in the existing coasting test standards for light-duty vehicles are followed to compare the stationary anemometer method with the onboard anemometer method. The aerodynamic equation for the onboard anemometer method is derived and simplified. Multiple vehicle prototypes are tested under identical environmental conditions, and the collected data are analyzed and compared. Findings indicate that at lower speeds, the onboard anemometer method yields more accurate wind speed measurements. However, at higher speeds, aerodynamic effects from the onboard anemometer on the vehicle increase, resulting in measurement deviations. Consequently, the onboard anemometer method is recommended for vehicles with lower maximum speeds, while the stationary anemometer method is more suitable for vehicles with higher maximum speeds to ensure precise driving resistance measurements. Furthermore, the derivation and simplification of the aerodynamic equation enhance the computational efficiency and accuracy of the testing process.

Key words: new energy light-duty vehicles, coast down, onboard anemometer method, stationary anemometer method, Emissions Standard of China Ⅵ