Energy Management Strategy For Dual Motors Planetary PHEV Considering Engine Start-stop And Emission Characteristics

Plug-in Hybrid Electric Vehicle(PHEV)can realize multiple power modes to switch alternately,which not only reduces the fuel consumption of the vehicle and the emission of exhaust pollutants,but also ensures a long range of the vehicle,which has a broad application prospect.However,traditional hybrid vehicles take fuel economy as the main goal,and their power performance indicators are often unsatisfactory.Therefore,a new configuration of dual-motor hybrid electric system is proposed in this paper,and the energy management strategy is studied according to the engine idle operation,frequent start-stop and emission characteristics.The main work of this paper includes:(Ⅰ)Build a mathematical model of PHEV powertrain with energy transfer and emission characteristics.Firstly,the architecture of the dual motor planetary train powertrain is proposed,and various typical working modes of HEV are analyzed.Secondly,the vehicle longitudinal dynamics model,engine model,motor model,driver model,power battery model,exhaust emission model and so on were established.(Ⅱ)Considering the change of engine fuel consumption under frequent start-stop or idle operation,an engine start-stop optimal control model was proposed,and an engine start-stop optimal control module was added on the basis of equivalent fuel consumption minimum control strategy(ECMS)to construct an energy management strategy considering engine start-stop.Particle swarm optimization algorithm is used to optimize the key time parameters of the stop-frequency of shadow sound in start-stop optimization control.The simulation results show that the proposed energy optimization strategy can effectively control the start-stop frequency and idle running time of the engine,and reduce the fuel loss caused by frequent engine start-stop.Compared with the optimization strategy,the fuel consumption of the engine is reduced by 5.4%,and the equivalent fuel consumption per 100 km is reduced by 4.1%.It is verified that the proposed energy management strategy can effectively improve the fuel economy of the vehicle.(Ⅲ)To further optimize the engine exhaust emissions,such as CO,HC,NO_x and so on,an adaptive ECMS energy management strategy considering the emission characteristics was designed,and the equivalent factors were optimized by genetic algorithm,so as to effectively control the engine exhaust emissions.The optimization results show that under NEDC,WLTC and HWFET,the designed energy management strategy can effectively reduce the emissions of CO,HC and NO_x,with the maximum reduction reaching 20%,18% and 21% respectively.(Ⅳ)A HCU-in-the-loop simulation(HiL)test platform for a PHEV vehicle with planetary coupling of two motors is built.Based on the above control strategy,a verification scheme for the comprehensive management strategy is established.The HiL test results under various driving conditions show that the proposed control strategy can effectively improve the fuel economy and reduce the exhaust emissions of the vehicle.The maximum deviation between theoretical simulation and HiL verification results is 11%,and the trend of the results is consistent,which effectively verifies the effectiveness and accuracy of the comprehensive management strategy.