基于控制的稀薄燃烧汽油机进气模型

Control-Based Intake Airflow Dynamics Model of Lean Burn Gasoline Engine

提高电控汽油机空燃比控制精度是改善发动机燃油经济性、动力性和降低尾气污染的关键环节.针对稀薄燃烧汽油机的工作原理及其排放控制要求,提出了改进的基于发动机物理模型的稀薄燃烧汽油机空燃比的控制方案.对方案中稀薄燃烧汽油机进气模型进行了详细描述,利用自行研制的发动机电控系统,采用最小二乘法对模型的主要参数进行辨识,并对影响模型参数的主要因素进行了简要分析.结果表明,进气管时间常数是发动机转速和节气门开度的函数,节气门开度越大,时间常数越小.

Enhancing the controlling accuracy of engine air-fuel ratio is an important method to improve the fuel economy and powering ability and reduce the pollution of tail gas. An improved model based on air-fuel ratio control structure has been developed according to the running theory and emission control requirement of lean burn gasoline engine. The concerned intake airflow dynamics model is described in detail. Employing the engine control system developed by ourselves, the key parameters in the model are determined by least-squares (identification) technique, and the brief analysis of the main factors influencing the parameters is given. The result shows that the time constant of the intake manifold is a function of engine rotate speed and throttle opening, and the more the throttle opening, the smaller the time constant.