Patent ID: 6918288
Filing Date: 2005-07-19
Classification: F02D,G01M

Abstract:
1. A method for detecting combustion misfires in multi-cylinder internal combustion engines having several simultaneously igniting cylinders, the method comprising the steps of: determining rough running values for each crankshaft rotation by measuring segment times, the segment times including the times, which correspond to the piston movement of individual cylinders after their ignition time point, wherein the crankshaft passes through an associated circular segment angular region; determining a combustion misfire from the determined rough running values for circular segment angular regions of individually igniting cylinders via a desired value comparison to a first threshold value SW assuming a combustion misfire in the affected crankshaft circular segment regions from the determined rough running values LUT for crankshaft segment regions having several simultaneously igniting cylinders by making a desired value comparison to a second threshold value SW for an assumed misfire in a crankshaft segment region having simultaneously igniting cylinders, causing a misfire operation in one of these cylinders with suitable engine intervention; and, determining the cylinder which has a combustion misfire without engine intervention by measuring the change of the rough running values in the crankshaft segment region having the simultaneously igniting cylinders after causing misfire operation caused by the engine intervention.