Study on the Relationship between External EGR and Gasoline-fueled HCCI Combustion

Homogeneous Charge Compression Ignition(HCCI) is a new technique in the field of combustion.In this paper the methods which can be used to facilitate the HCCI combustion are introduced.The use of recycling of burnt gases(EGR) is considered probably the most appropriate method to achieve HCCI combustion in a 4-stroke gasoline engine and it can be obtained by closing the exhaust valve relatively early.The effect of external EGR on HCCI combustion is analyzed simply.The problems(such as pumping loses and backflow loses) which are caused by changing valve timing in order to trapping residuals are illustrated.