Analysis on the Characteristics of Ionic Current Signal and Its Application in S.I. Engine

摘要

This paper analyses three stages of ionic current signal in ignition and combustion by measuring the ionic current via spark electrodes and pressure at the same time in a constant volume combustion bomb and contrasting the images taken by the high speed camera in combustion with the corresponding ionic current signals. It is presented that the ionic current of ignition period relates mainly to induced voltage by spark discharge during ignition; that of the initial period of flame development relates mainly to the flame kernel round the poles; that of the later period of combustion connects with all kinds of ions and electrons in burned area. The primary characteristics and differences during the later period of combustion of ionic current are analyzed respectively by band-pass filter method and peak raw data method when the engine operates at the different conditions such as formal combustion, knock and misfire. The results show that knock and misfire can be detected effectively by measuring ionic current during later combustion.