Development of Anti-knock Control Method Using Multiple Fuel Injection in Direct Injection Gasoline Engines

Engine downsizing and higher compression ratio attract attention as a method for improving fuel economy of internal combustion engines. Knocking of an engine is one of the critical factors in determining the engine performance in these systems. In this research, a method for anti-knock control in gasoline direct injection engines was developed based on 3-dimensional fluid simulation and experimental approach. It was clarified that hot spots due to residual gas in the combustion chamber contributed to occurrence of knocking, and a method for cooling the mixture using multiple fuel injection was effective to suppress knocking without increasing smoke emission.