Patent ID: 6023651
Filing Date: 2000-02-08
Classification: F02D,G01M

Abstract:
A misfire detecting apparatus for an internal combustion engine, said apparatus comprising:means for outputting a rotation signal indicative of an engine output shaft rotation;means for calculating rotational speed of said shaft based on said rotation signal in connection with cylinder firings;means for calculating an elementary term representing variation in said rotational speed between firings of two selected cylinders separated by a predetermined number of cylinder firings;means for calculating a correcting term by dividing a variation in rotational speed of said shaft for cylinder firings separated by a predetermined number of combustion cycles for one of the selected cylinders by an integer multiple of a total number of engine cylinders; andmisfire detecting means for correcting the elementary term with the correcting term and for detecting a misfire of the internal combustion engine based on the thus corrected elementary term.