Saturn Corporation

Jeffrey R Drexel

Larry T Nitz

William Joseph Bolander

Mark De Backer

Synchronization of relative engine angular position information is provided in the absence of an absolute engine position input signal by inducing misfires in a known engine cylinder and then monitoring misfire behavior over a test period. If significant misfire activity does not occur in an engine cylinder assumed, in accord with an assumed engine absolute position, to correspond to the known engine cylinder, then the assumed engine absolute position was not correct and is corrected through application of a position offset to the assumed position. Misfires are induced and the absolute position corrected when the engine is operating at a level assumed to be insensitive to the misfires and the correction.

Engine synchronization

Internal combustion engine misfires are diagnosed through monitoring of change in engine speed wherein an acceleration spike index is generated for each cylinder event over a number of engine cycles in a test period and is corrected in accord with sensed part tolerancing, and wherein the corrected acceleration spike index is compared to at least one misfire threshold. For each engine cylinder, a degree of misfire severity is diagnosed at the end of the test period in accord with the frequency of excursions by the corresponding misfire index above the at least one misfire threshold.

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Rochester Hills, MI, United States of America

Jeffrey R Drexel