Proposal of Knock Mitigation Method through Enhancement of Local Heat Transfer

Abstract

For enlarging the knock limit of SI engine to realize further increases in thermal efficiency, the authors proposed a simple method to promote local heat transfer through moderate enhancement of the gas flow at the point of origin of knock, in order to lower the end-gas temperature and by this means retard auto-ignition timing. The use of the proposed method advances the combustion phase 2.2 degree without increasing the discharge of unburned exhaust components, and this advance in the combustion phase increases IMEP by 17.2 kPa.