Misfire detection method robust against crankshaft vibration and acceleration

We discuss a factor which disturbs misfire detection at high engine speed on the basis of a crankshaft vibration analysis. According to this analysis, the detection window size was changed. Engine test showed the possibility of misfire detection improvement. Then, a filter which can detect not only periodic misfire but also isolated misfire is proposed. The filter is robust against acceleration. The performance of the filter was evaluated by engine test