汽油机起动过程HC排放形成及转化模型

Formation and Conversion Model for HC Emission of Gasoline Engine during Starting Process

采用HC形成模型和三效催化转化器模型相结合的方法,对汽油机起动过程HC排放进行研究。建立了燃油分布模型,研究了缸内油膜的湿壁效应、狭隙效应、吸附和解吸以及不完全燃烧对HC排放的影响,在此基础上建立了起动过程HC排放形成模型。考虑了氧气的存储和释放对有效空燃比的影响,以温度和有效空燃比为输入量,利用集总参数法建立了三效催化转化器模型。测量并比较了不同冷却液温度下汽油机起动过程HC排放值,仿真结果与实测结果较为吻合,为汽油机起动过程HC排放预测提供了参考。

Combining both HC formation model and three-way catalytic converter model,the HC emission of gasoline engine during starting process was studied.The fuel distribution model was built and the influences of in-cylinder wall wet effect,crevice effect,absorption/desorption and incomplete combustion on HC emission were analyzed.Based on this,the formation model of HC emission during starting process was built.Considering the influence of oxygen storage and release on effective air-fuel ratio,the three-way catalytic converter model was built with the lumped parameter method by taking the temperature and effective air-fuel ratio as input variables.The HC emissions during starting process were measured and compared under different coolant temperature conditions.The simulation results coincided with the experiment results,which provided the reference for the HC emission prediction of gasoline engine during starting process.