Energy management strategy for hybrid electric vehicle based on system efficiency and battery life optimization

A novel method to calculate fuel-electric conversion factor for full hybrid electric vehicle (HEV) equipped with continuously variable transmission (CVT) is proposed. Based on consideration of the efficiency of pivotal components, electric motor, system efficiency optimization models are developed. According to the target of instantaneous optimization of system efficiency, operating ranges of each mode of power-train are determined, and the corresponding energy management strategies are established. The simulation results demonstrate that the energy management strategy proposed can substantially improve the vehicle fuel economy, and keep battery state of charge (SOC) change in a reasonable variation range.