The relationships between air flow metering and combustion control for spark ignition engines, such as engines with three way catalysts, lean NOx catalysts, two stroke engines and direct fuel injection engines were investigated. The effects of control parameters on combustion were analysed and the relationships between control parameters and air flow metering and roles of the meters in combustion control were clarified. The control strategies adaptable to many types of engines which have a wide control range of the air/fuel mass ratio are classified as (1) air quantity control,(2) fuel quantity control, and (3) exhaust gas recycle quantity control. The control parameters for the three strategies are fuel quantity, air quantity, exhaust gas recycle quantity, exhaust gas temperature, knocking, excess air factor, and mixture quality with additional parameters of swirl ratio, and spark timing for conventional spark ignition engines, two stroke engines and direct injection engines.
In this study, the possibility of real-time HCCI control in a multi-cylinder gasoline engine was examined. Specifically, we applied a multivariate analysis based on an experimental design of quality engineering, and picked out several engine parameters which influence gasoline HCCI combustion stability. We clarified the characteristics of engine parameters in a gasoline HCCI operation area and propose the control concept: The internal EGR control is applied to multi-cylinder control by using the variable valve system, and air-fuel mixture control is applied to each-cylinder injection control while keeping the mixture homogeneous. Combustion conditions and engine out A/F need to be detected and fed back individually for each cylinder. With the proposed concept, it is possible to construct a real-time HCCI control system in a multi-cylinder gasoline engine.