Abstract
Homogeneous charge compression ignition (HCCI), also called as controlled auto ignition combustion (CAI), is recent combustion technology which has caught attention of automotive manufacturers all over world because of its ability to eliminate NOx and particulate emissions. HCCI combines advantages of both spark ignition and compression ignition engines. This paper focuses on current research work on HCCI direct and port fuel injected gasoline engines. It contains basic comparison between performance of gasoline injected engines and carburetted engines. This comparison is related to parameters like power output, fuel consumption, brake thermal efficiency and emissions. Paper also contains information about HCCI combustion and its merits.