Performance Characterization of a Direct Injection LPG Fuelled Two-Stroke Motorcycle Engine

To quantify the fuel consumption and emissions improvements of Direct fuel Injection (DI), measurements were taken from a two-stroke motorcycle engine while operating in premixed, and direct injection mode burning propane. The part-load lean combustion limit was investigated for the DI technique in both premixed and DI modes. Results were compared to a one-dimensional Computational Fluid Dynamics (CFD) model of the engine. Results indicate that a highly stratified mixture can not be achieved due to poor mixing. The DI technique yields significant reductions in HC emissions, and significantly improved fuel economy, though not as good at Gasoline Direct Injection (GDI). Finally an economic analysis indicates that a gaseous fuel DI retrofit system represents a significant cost savings over a gasoline DI retrofit system.