Optimal engine speed compensation method used in misfire detection

摘要

The present invention provides a method and system for detecting engine misfire with an optimal compensation of the RPM signal in an internal combustion engine in which the data signal containing a plurality of groups of sample data points is generated. Each of the groups of sample data points represents a cylinder firing event. The data signal is then conditioned for misfire detection processing. The data engine cycle compensation vectors for the RPM zone is then multiplied to the sample data of the RPM. Each group of sample data points is processed using signal processing techniques and then mapped into a single mapped data point. The mapped data points are further processed and then compared to a misfire detection dynamic threshold. A misfire detection signal is then output if any of the mapped data points fall outside the dynamic threshold. The misfire detection system achieves high degree of accuracy through a signal processing and statistical detection technology. The on-line RPM signal compensation reduces the effects to misfire detection caused by the RPM error from various sources and it further enhances the detection performance.