基于燃油经济性的Atkinson循环发动机优化设计研究

Research on Optimization Design of Atkinson Cycle Engine Based on Fuel Economy

[目的]将传统Otto循环发动机改型设计为混合动力Atkinson循环发动机,以提高发动机燃油经济性。[方法]以某Otto循环发动机为原型机,建立发动机GT-power仿真模型,通过提高发动机压缩比,增大进气凸轮工作包角,将原机仿真模型改型为Atkinson循环发动机仿真模型。利用Atkinson循环发动机仿真模型对发动机进气凸轮工作包角、进气门关闭时刻和排气门关闭时刻进行优化分析,确定最佳参数。[结果]Atkinson循环发动机在外特性工况下扭矩有所下降,燃油消耗率最高降低了7.2%;最低燃油消耗率由原型机的244 g/kW·h降至235 g/kW·h,低油耗区域转速范围增大。[结论]试验结果显示,优化后的Atkinson循环发动机燃油经济性得到了改善,满足混合动力汽车对发动机的工作需求,证明了优化设计方法的可行性。

[Purposes]This paper redesigns the traditional Otto cycle engine into a hybrid Atkinson cycle en-gine to improve engine fuel economy.[Methods]Using the Otto cycle engine as a prototype,a GT-power simula-tion model of the engine was established.By increasing the compression ratio of the engine and the working angle of the intake cam,the original simulation model is modified into an Atkinson cycle engine simulation model.The Atkinson cycle engine simulation model is used to optimize and analyze the working angle of the en-gine intake cam,the closing time of the intake valve,and the closing time of the exhaust valve,thus determining the optimal parameters.[Findings]The Atkinson cycle engine shows a decrease in torque under external charac-teristic conditions,with the highest fuel consumption rate reduced by 7.2%;the minimum fuel consumption rate has decreased from 244 g/kW·h of the original engine to 235 g/kW·h,and the speed range in the low fuel con-sumption area has increased.[Conclusions]The experimental results show that the fuel economy of the opti-mized Atkinson cycle engine has been improved,meeting the working requirements of hybrid vehicles for the engine,and proving the feasibility of the optimization design method.