Process Control of Mode Switch for Parallel Hybrid Electric Buses

The control strategy of mode switch with engine started and not started was designed for the mode switch that needs engagement of clutch on single-shaft parallel hybrid electric vehicle (HEV). The clutch friction work and driver's intention were taken into account to determine the control strategy of starting the engine in particular gear or in neutral gear when the engine did not started. The motor could compensate engine torque during torque recovery phase and the compensation strategy was developed according to driver's demand, battery status and vehicle control strategy. The feasibility and superiority of the strategy were verified by bench and vehicle tests.