Patent ID: 6357287
Filing Date: 2002-03-19
Classification: F02D,G01M

Abstract:
A system for detecting a misfire of an engine, comprising:a flywheel connected to a crank shaft and having teeth; a magnetic pickup generating analog signals according to variations of a magnetic field caused by a difference of a distance between a tooth and a bottom of a tooth space on the flywheel; a switching circuit receiving the analog signals and outputting digital signals; a timer and counter detecting a period of the digital signals and a number of HIGH values; an electric control unit (ECU) receiving the period of the digital signals and the number of the HIGH values to detect the misfires of the engine, wherein the ECU receives the period of the digital signals and the number of the HIGH values detected from the timer and counter, and finds an angular acceleration of the flywheel, and performs frequency analysis on the angular acceleration based on a Walsh function as a basis function so as to find a magnitude of an amplitude of frequency components, and compares the magnitude of the amplitude with a predetermined reference value so as to determine an occurrence of a misfire.