BRAKING FOR ELECTRIC CAR IN BEIJING

Qiu Bin  Chen Quanshi

(State Key Laboratory of Automotive Safety and Energy, Tsinghua University, Beijing 100084)

Zhang Kaibin

(Department of Vehicle Test and Research, Chongqing Automobile Research Institute, Chongqing 400039)

Abstract: Based on the analysis of various factors that may affect the potential of regenerative braking and an electric sedan prototype, the statistical characteristic of maximum braking power under different velocity is obtained from logged drive cycle data of a Beijing Xidan, which shows high accordance with the characteristics of electric motor. Then the net braking energy and available braking energy under typical road are analyzed, the results indicates that the maximum range improvement of regenerative braking, even in frequently stop-and-go Chang’an Street, is about 24.4%. Finally the two-dimensional distributions of braking energy to velocity-deceleration of EV(electric vehicle) and revolution-torque of electric motor are analyzed, which illustrates that the region rich in braking energy does not coincide with high regenerative braking efficiency region of electric motor. To improve the potential of regenerative braking, the design of electric drive system should consider the all-sided statistical results of drive cycle investigation, i.e., a comprehensive electric drive system design must consider not only the requirement for propulsion performance but also the potential of regenerative braking.

Key words:Electric vehicle  Regenerative braking  Drive cycle

CLC No: U463.23

国家863计划资助项目(2003AA501100). Received 20050105, received in revised form 20050809