S.I. Engine Misfire Detection Through the Energy Model

This paper describes the method to detect S. I. engine misfire for the OBD II requirement. In most methods related to the misfire detection, the fluctuation of crankshaft speed is used as an input parameter[1, 2, 3, 4 and 5].

If the misfire detection is performed by the pattern of crankshaft speed without considering the engine dynamics, it is difficult to determine the misfire at high speed and low load condition. So this paper proposed the single degree of freedom energy model of engine dynamics for the misfire detection. Through this model the integral of torque by cylinder pressures are estimated using the variation of crankshaft speed and it is possible to detect the misfire by this integral value.