Robert Boschgmbh

Hartmut Dietz

Klaus Ries-Muller

Jurgen Forster

The invention is directed to a method for detecting misfires in the combustion of a z-cylinder four stroke internal combustion engine wherein the engine includes a transducer wheel coupled to the crankshaft of the engine and rotating in phase synchronism with the crankshaft. The transducer wheel has typically z/2 segments and the segments are scanned with a sensor device to supply a segment-time signal reflecting the nonuniformity of the rotational movement of the crankshaft with respect to individual ones of the cylinders of the engine. Rough-running values are formed for each cylinder on the basis of the segment times with each of the rough-running values including a component occurring at the frequency of the crankshaft. The component is filtered out and then the filtered rough-running value is compared to a threshold value. A misfire is determined to be present when the filtered rough-running value exceeds the threshold value.

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Stuttgart, Germany

Hartmut Dietz