Gasoline Direct Injection - A Promising Engine Concept for Future Demands

This paper summarises the potential for the use of a gasoline direct injection engine for fuel economy benefits. Various engine technologies are compared for the greatest reduction in fuel consumption at the steady state point 2000rpm/2 bar. This is an important driving point in the EU cycle. The direct injection engine when used in an unthrottled lean stratified mode shows the greatest potential. Calculations show a fuel economy of a middle class vehicle can be increased by 12% using a DI over the EU cycle.

The catalytic aftertreatment system is discussed and it is concluded that a close coupled pre-catalyst, a NO_x trap and double injection are a good overall solution for the minimisation of exhaust gas emissions from a DI engine.