Study of the Effect of Spark Ignition on Gasoline HCCI Combustion

Abstract

Homogeneous charge compression ignition (HCCI) has challenges with regard to ignition control. A spark-assisted gasoline HCCI combustion strategy was used to control ignition of HCCI combustion. In this paper, the effects of spark ignition (SI) on HCCI combustion were investigated on a gasoline direct injection (GDI) engine. The experimental results show that SI improves the stability of HCCI combustion at HCCI critical status (HCCI-CS). At the transition from SI to HCCI mode, the transition fluctuations can be smoothed by the SI in SI/HCCI hybrid combustion engine. Local SI can trigger entire HCCI in the cylinder at sub-HCCI-CS. Without SI, misfire occurs at sub-HCCI-CS. The reason is that local high temperature and pressure owing to local heat release from the spark electrode leads to increase of temperature and pressure in the entire cylinder. When the temperature and concentration of mixture are below sub-HCCI-CS, SI has little effect on HCCI ignition.