Research On On-line Detecting Of In-cylinder Burning State By Ion Current Signal

A new engine testing method, namely the ion current is introduced. Ion current method has the characteristics of easy realization, lower cost and rapid response, and has no change for engine. It can detect several parameters simultaneously. The ion current method has a bright future for application, for it is a new way of engine control and diagnosis.According to the current equipment in laboratory, the research on on-line detecting of gasoline engine burning state by ion current signal is carried out.The burning state of gasoline engine is discussed, which is the background for ion current method applied to detect engine burning state. The generating causation and physical phenomenon of ion current are presented. Three models of the ion current are discussed, and the principle of the model used in this paper is explained. The influence factors of ion current are analyzed. The detecting system of gasoline engine burning state is established based on ion current method, and the wave form of ion current is obtained. The relation between ion current and cylinder pressure which can show the burning process of engine control is validated on an AJR engine. The knock and misfire of the engine are detected by ion current method which is a new way of engine diagnosis. In the end, the problems in ion current method are discussed and further researches are pointed.