Shinichiro Nogawa

Study of Ignitability in Strong Flow Field

To respond to the social requirement such as energy security and climate change, engine thermal efficiency has been improved. The use of charge dilution such as lean combustion and exhaust gas recirculation (EGR) has been considered as effective option to meet these requirements. In diluted combustion, in-cylinder flow-structures such as tumble are used to intensify in-cylinder turbulence and promote flame propagation. However, it is not clarified how it can contribute to the formation of flame kernel and promotion of the flame propagation under highly turbulent and diluted charge conditions. The purpose of this study is to achieve superior thermal efficiency with stable ignitability under high in-cylinder flow and diluted charge conditions. This paper describes the effect of flow velocity and turbulence intensity on the ignitability through analysis of the discharge channel behavior and initial stages of combustion phenomenon such as formation of flame kernel and flame propagation.