초록 ▼

An apparatus and method are provided for detecting cylinder misfires in an internal combustion engine of a motor vehicle which provides a good signal to noise ratio and is capable of distinguishing from noise related events such as misfire induced bobble and harsh clutching maneuvers. Crankshaft rot

An apparatus and method are provided for detecting cylinder misfires in an internal combustion engine of a motor vehicle which provides a good signal to noise ratio and is capable of distinguishing from noise related events such as misfire induced bobble and harsh clutching maneuvers. Crankshaft rotation is sensed and crankshaft velocities are measured for each cylinder. Changes in angular velocity are determined and correspond to each of a plurality of cylinder firing events. With a first averaging filter, angular velocity changes are sorted over a predetermined series of cylinder firings and the two middle angular velocity changes are averaged to provide an average change in velocity value. A deviation is determined between the change in angular velocity for a selected cylinder and the average change in velocity. With a second averaging filter, the deviations from the first averaging filter are sorted over a series of cylinder firings and the two middle most deviations are averaged to provide an average change of deviation thereof. A second deviation is determined between the change in the first deviation for a selected cylinder and the average deviation value. The second deviation is compared to a threshold value and a misfire event is determined for the selected cylinder based on the comparison. Any number of two or more cascade connected average filters may be employed.

대표청구항 ▼

An apparatus for detecting misfires of cylinder firings in an internal combustion engine comprising: means for measuring changes in engine speed corresponding to each of a plurality of expected cylinder firings; first filter means for calculating an average change in engine speed over a plurality of

An apparatus for detecting misfires of cylinder firings in an internal combustion engine comprising: means for measuring changes in engine speed corresponding to each of a plurality of expected cylinder firings; first filter means for calculating an average change in engine speed over a plurality of cylinder firings for each expected cylinder firing and determining a first deviation between the average change in engine speed and a current change in engine speed corresponding to each expected cylinder firing, said first filter means outputting a series of said first deviations; second filter means for calculating an average change in the first deviations output from the first filter means and determining a second deviation between the average change in first deviations and a current change in the first deviations corresponding to a selected cylinder; and comparison means for comparing the second deviation of the second filter means to a threshold value to determine if a misfire has occurred for the selected cylinder.