Abstract: The powertrain of the parallel-series hybrid electric vehicle(PSHEV) is discussed for its features of dual-motor structure in which powers from the engine and the tractive mo-tor are coupled at the output shaft of the transmission instead of the input shaft. Control strategies based on ICE optimal oper-ating schedule are utilized to improve the powertrain efficiency and reduce fuel consumption. To identify the power demand of the driver, a new “nine-point-definition method” is proposed. Special attention is given to the combination control of differ-ent power sources during gear shifting. Regenerative braking is divided into the braking mode and the coasting mode and dif-ferent control methods are applied for each mode. A hybrid powertrain controller (HCU) based on CAN network is devel-oped 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 under the coordination of HCU the vehicle achieves 35% reduction in fuel consump-tion and improvement in acceleration performance.

Key words: Control strategy, Gear shift combination control, Hybrid powertrain, ontroller, Parallel-series hybrid electric vehicle, Dynamic magnetic field, Magnetorheological finishing, Normal force, Polishing pad, Torque