A Study of Controlling the Auto-Ignition and Combustion in a Gasoline HCCI Engine

This paper describes a combustion stability control using fuel injection control for a gasoline homogeneous charge compression ignition (HCCI) engine. First, using a single-cylinder engine we examined the influence that fuel injection and air/fuel mixture had on HCCI engine auto-ignition and combustion. This was achieved by visualization experiment of in-cylinder air/fuel mixture with fuel injection as a parameter. Next, the effect of the fuel injection control was evaluated by using a 4-cylinder HCCI engine. We proposed the following concept for a gasoline HCCI combustion control: internal-EGR (I-EGR) is applied to either internal EGR control of each-cylinder or a multi-cylinder control scheme using a variable valve event and timing system, and the fuel injection is applied to each cylinder control while keeping the mixture homogeneous. Using the proposed concept, we could reduce torque variance that occurred due to combustion instability, while the emissions of NOx and HC also were decreased.