Trade-off on fuel economy, knock, and combustion stability for a stratified flame-ignited gasoline engine

A combination of port fuel injection (PFI) and direct injection (DI), called P-DI strategy, was used in a four-cylinder gasoline engine. The aim was to achieve a stratified flame ignition (SFI) hybrid combustion and manage the trade-off among fuel economy, knock, and combustion stability (EKS) in a gasoline engine. In the proposed P-DI strategy, DI was used to enrich the local mixture around the spark plug to enhance the early spark-ignition...