考虑发动机排气背压阈值的柴电混合动力汽车最优控制

The optimal control of plug-in diesel hybrid electric vehicle with considering the threshold of exhaust back pressure

中文关键词  混合动力汽车  柴油发动机  排气背压  极小值原理  最优控制  排放

英文关键词  hybrid electric vehicle  diesel engine  exhaust back pressure  pontryagin’s minimum principle  optimal control  emission

中文摘要

      根据柴油发动机台架试验结果, 分析排气背压对发动机性能的影响, 在设计插电式柴电混合动力汽车(plug-in hybrid electric vehicle, PHEV)控制策略时考虑排气背压对油耗与排放的影响因素. 以排气背压和蓄电池荷 电状态为状态变量, 利用庞特里亚金极小值原理, 求解以插电式混合动力汽车油耗与颗粒物排放量的多目标泛函,从而得到整车油耗与排放综合最优控制策略. 在MATLAB/Simulink仿真平台下建立了包含柴油颗粒过滤器(diesel particle filter, DPF)压力损失和捕集效率模型的整车动力学模型, 对上述所得最优控制策略进行验证, 并与二阶段(charge-depleting and charge-sustaining, CD–CS)控制策略和无排气背压状态最优控制策略进行对比. 仿真结果表明, 本文建立的最优控制策略相对于其它两种控制策略均能明显降低排气背压升高对发动机性能的影响, 有效地改善了整车燃油经济性和排放性. 最后通过台架试验对所提出的最优控制策略的有效性进行验证, 结果表明, 采用该控制策略优化后的等效燃油消耗量与颗粒物(particulate matter, PM)排放量分别降低了9.68%和32%.

英文摘要

      The influence of exhaust back pressure for the engine performances is analyzed according to the experiment results from diesel engine test rig. In order to obtain the comprehensive optimization of the fuel and emission of plug-in hybrid electric vehicle (PHEV), this paper pays attention to the effects of exhaust back pressure on fuel economy and emission in the design of the PHEV control strategy. Then multi-objective cost function relating to the exhaust back pressure and the battery’s state of charge have been establish and solved by Pontryagin’s Minimum Principle. In order to validate the effectiveness of the control strategy we proposed, the vehicle dynamic model including the pressure drop model and collection efficiency model of diesel particle filter (DPF) has been established in the MATLAB/Simulink platform. Other three control strategies, the charge–depleting and charge–sustaining (CD–CS), single PMP (S–PMP) and double PMP(D–PMP) control strategies are implemented for comparison at the same time. Simulation results show that the optimal control strategy proposed in the paper significantly eliminate the effect of increasing exhaust back pressure on the engine performance.The fuel economy and emission performance has been improved effectively. In order to further verify the effective of the proposed optimal control strategy, the bench tests experiment are conducted. The results show that the equivalent fuel consumption and PM emission is reduced by 15.28% and 34.25% respectively.