광역 산소센서를 이용한 실화감지-실화가스의 흐름 및 센서 응답특성의 영향

Abstract

As a new concept of misfire detection, monitoring the signal variation of a wide range oxygen sensor has been investigated. The sensor signal fluctuates in a constant pattern that has twin peaks, irrespective of engine operating condition, when a misfinrg is occured. It was proved to detect misfire reliably by differentiating the sensor signal, up to an engine speed of 5000rpm. In this study, the flow characteristics of misfired gas in the exhaust manifold and the oxygen concentration fluctuation at the confluence point were investigated to understand why the sensor signal fluctuats in a pattern that has twin peaks, Transient response of the sensor for misfiring condition and its effect on the signal output were also investigated. The monitoring parameter for the identification of misfiring cylinder was decided considering the cyclic variation of misfired gas flow. The reliability of faulty cylinder identification was respresented by the histogram and the deviation of the cyclic variation.