Development of Hybrid Powertrain Controller for a PSHEV

The hybrid electric vehicle (HEV) discussed in this paper features its post-transmission configuration, which enables the tractive motor to drive the vehicle even in neutral gear. A generator is attached to the engine to charge the battery. Development of control system of the powertrain is reported in this paper. Control strategies based on ICE optimal operating schedule are utilized to reduce fuel consumption and improve the powertrain efficiency. To identify the power demand of the driver, a new "nine-point-definition method" is proposed in this paper. Special attention is given to the coordinated control of different power sources during gear shifting. The regenerative braking process is divided into the braking process and the coasting process and different control methods are applied for each. A hybrid powertrain control unit (HCU) based on CAN network is developed to implement these strategies, which is proved to be able to work efficiently and stably by hardware-in-loop experiment and on-board test. Test results show that 35% reduction in fuel consumption and improvement in acceleration performance are achieved.