Research on Plug-in Hybrid Electric Vehicle (PHEV) Energy Management Strategy with Dynamic Planning Considering Engine Start/Stop

The key to improving the fuel economy of plug-in hybrid electric vehicles (PHEVs) lies in the energy management strategy (EMS). Existing EMS often neglects engine operating conditions, leading to frequent start-stop events, which affect fuel economy and engine lifespan. This paper proposes an Integrated Engine Start-Stop Dynamic Programming (IESS-DP) energy management strategy, aiming to optimize energy consumption. An enhanced rule-based strategy is designed for the engine's operating conditions, significantly reducing fuel consumption during idling through engine start-stop control. Furthermore, the IESS-DP energy management strategy is designed. This strategy comprehensively considers engine start-stop control states and introduces weighting coefficients to balance fuel consumption and engine start-stop costs. Precise control of energy flow is achieved through a global optimization framework to improve fuel economy. Simulation results show that under the World Light Vehicle Test Cycle (WLTC), the IESS-DP EMS achieves a fuel consumption of 3.36 L/100 km. This represents a reduction of 6.15% compared to the traditional DP strategy and 5.35% compared to the deep reinforcement learning-based EMS combined with engine start-stop (DDRL/SS) strategy. Additionally, the number of engine start-stop events is reduced by 43% compared to the DP strategy and 16% compared to the DDRL/SS strategy.