Abstract
Direct injection spark ignition (DISI) gasoline engines are becoming popular due to their potential for improved fuel economy and exhaust emissions. The performance of a direct injection gasoline engine is highly dependent on the quality of the air-fuel mixture preparation. This is very important when operating at a stratified charge condition, where the ideal mixture distribution would be a stoichiometric region around the spark plug, surrounded by air. To achieve this ideal situation over a wide range of speeds and loads is extremely difficult, requiring an understanding of the fuel spray, the in-cylinder air motion and their interactions. This paper contains several investigated sub-topical areas within DISI engine technology. Research in recovering power density, DISIs opportunity to extend knock-limited performance and, of course, the role of injector design, combustion chamber design, and charge preparation, in further reducing the engine-out gaseous and particulate emissions is discussed.