ENGINE MISFIRE DETECTION SYSTEMS AND METHODS USING DISCRETE FOURIER TRANSFORM APPROXIMATION

摘要

A method of detecting a misfire of an engine includes determining a range of sub-harmonic frequencies of one of a crankshaft sensor signal and an engine speed signal. The range of sub-harmonic frequencies is determined based on a fundamental frequency. The sub-harmonic frequencies are less than the fundamental frequency. Frequency content magnitudes are generated based on the range of the sub-harmonic frequencies and a Discrete Fourier Transform of at least one of the crankshaft sensor signal and an engine speed signal. An energy from velocity non-uniformity (EVN) signal is generated based on the frequency content magnitudes and the range of the sub-harmonic frequencies. The misfire is detected based on the EVN signal and a misfire threshold.