Low speed pre-ignition (LSPI) is one of the difficult issue in the turbocharged gasoline direct injection (GDI) engine. Pre-ignition is a kind of heavy knock of which pressure rise starts before ignition by spark plug. High load/low speed condition at...
Low speed pre-ignition (LSPI) is one of the difficult issue in the turbocharged gasoline direct injection (GDI) engine. Pre-ignition is a kind of heavy knock of which pressure rise starts before ignition by spark plug. High load/low speed condition at high ambient temperature has risk of going into LSPI which makes engine damage such as spark plug and piston and big accident. In this study, the effects of valve timing, start of injection, lambda, and ignition timing on knock/PI characteristics have been investigated to protect LSPI. Knock/PI intensity and frequency could be restrained by valve overlap increase, late injection, rich air/fuel mixture, and retarded ignition timing. Valve overlap increase was one of excellent method to suppress the knock/LSPI without torque reduction.