Process for detecting a misfire in an internal combustion engine and system for carrying out said process , exhaust gas pressure sampled at a rate proportional to the crankshaft rotational speed

摘要

A process for detecting a misfire in one or more cylinders (3, 3') of an internal combustion engine, has the following operative steps: sampling the exhaust gas pressure values during at least one engine cycle, the sampling frequency being proportional to the crankshaft rotational speed; analyzing the sampled signal in the frequency domain; calculating a misfire index as a function of the results of said analysis; comparing said index with one or more threshold values. The frequency domain analysis includes a Fourier transform of the sampled signal.