Abstract: Different from traditional internal combustion engine vehicles， hybrid electric vehicles (HEVs) have regenerative braking capability to improve fuel economy. Taking a plug-in parallel HEV with axles torque coupling as the research object， the influences of regenerative braking were analyzed. A regenerative braking control strategy using fuzzy control was then proposed. The presented strategy was to make two-layers control decision. The braking torque was allocated between the front axle and rear axle in the top layer， while the algorithm in bottom layer split the rear axle braking torque between mechanical braking and electric braking. The strategy was evaluated in a simulation study using several typical driving cycles. The results show that the as-proposed fuzzy control strategy can significantly improve the effect of energy recovery up to 23.44%， compared with that of the traditional ideal braking force distribution curve strategy.

Key words: hybrid electric vehicle, torque coupling, regenerative braking, fuzzy control, energy management