Patent ID: 6439198
Filing Date: 2002-08-27
Classification: F02D,G01M

Abstract:
A method for detecting combustion misfires in a multi-cylinder engine wherein, for each crankshaft rotation, segment times elapse during operation of the engine and each segment time corresponds to a piston movement of a cylinder to be measured and is the time in which the crankshaft passes through a circular segment angular region, the method comprising the steps of:individually determining the rough-running values (LUT) for each cylinder of the engine by measuring the segment times; detecting combustion misfires on the basis of said rough-running values; pregiving a first threshold value (SW1) for detecting combustion misfires; comparing the determined rough-running values (LUT) in a is desired value comparison to a second threshold value (SW2) which is, in value, substantially less than the first threshold value (SW1) pregiven for detecting misfires; reducing the first threshold value (SW1) to a lower level when: (a) when there is a regular drop below the second threshold value (SW2) within a pregiven time interval (&Dgr;t); or, (b) during a specific number of engine revolutions (&Dgr;u).