Abstract: A shift schedule for automatic transmission of the plug-in hybrid electric vehicle(PHEV), and a torque distribution strategy between engine and motor are devised. By adjusting the gear of the automatic transmission and the output torque of the engine and motor, the control strategy allows the engine run along the best fuel economy curve, electric motors work in the high efficiency area, and ensure the charge or discharge current of the battery are less than twice the rated capacity. Therefore, the integrated optimal control for automatic transmission, engine, motor and battery is realized. The performance of the control strategy is tested by the PHEV simulation model, the simulation results show that this method guarantees each component can work in the optimal state and can improve the fuel economy when PHEV drove in the city cycle.

Key words: Control strategy, Plug-in hybrid electric vehicle, Shifting schedule, Torque distribution