An engine misfire diagnosis system and method using Discrete Fourier Transform and amplitude change analysis of engine speed

摘要

The present invention relates to an engine misfire diagnosis system and a method thereof using the discrete Fourier transform and an amplitude change analysis of an engine speed. According to an embodiment of the present invention, the system can diagnose whether a misfire has occurred or not in a four-cylinder engine by using an output signal of a crankshaft position sensor, comprising: a discrete Fourier transform unit to perform the discrete Fourier transform on output signal data of the crankshaft position sensor from Cycle 1 to Cycle N; a power spectrum density (PSD) calculation unit to calculate the PSD based on the output signal data of the crankshaft position sensor from Cycle 1 to Cycle N, with the discrete Fourier transform conducted through the discrete Fourier transform unit; and a misfire occurrence diagnosis unit to diagnose whether a misfire has occurred or not in the engine based on a harmonic order value where the maximum value of the PSD calculated by the PSD calculation unit appears.