Engine start control for electro-mechanical transmission system based on information prediction

When the electro-mechanical transmission (EMT) system switches to hybrid drive mode from pure electric mode, it is required to crank and start the engine. Due to the response lag of engine, the motor usually provides additional driving torque to ensure the power performance of vehicle. However, the excessive motor torque can cause too large a battery discharge current, in particular, when battery temperature is relatively low, may affecting the service life of battery. In this paper, an engine start control strategy for EMT system is proposed based on predictive information. Firstly by sampling the present and past information on system torque requirement and applying adaptive recursive multi-step predictive algorithm, the online prediction on the required torque of system is completed. Then the predicted information on the torque requirement of system is used to control engine starting process with the phenomenon of battery overload avoided. Hence on the premise of ensuring vehicle power performance, battery life can be effectively extended.