Misfire Detection Method Robust against Road Noise and Vehicle Body Jolting

As the automobile emission regulations become stringent, the requirements for engine diagnosis system become severe. Misfire detection is among the engine diagnosis function, which is disturbed by crankshaft vibration, engine acceleration, road noise, vehicle jolting, and so on. In this paper, a misfire detection method which is robust against road noise and vehicle body jolting is proposed. This method uses the ratio of two filters´ output to detect the frequency difference between misfire and disturbances. The evaluation of the method on road was reported.