Adaptive method of cylinder misfire detection in an internal combustion engine
First Claim
1. An adaptive method of detecting a misfiring cylinder in a spark-ignited internal combustion engine controlled by an electronic controller having memory, the method comprising the steps of:
- normalizing an engine acceleration-independent and engine speed-independent power cycle time differential signal for particular cylinder, obtained from consecutive power cycle time periods of an engine cycle, utilizing a calibration parameter stored in the memory for the particular cylinder, to obtain a normalized power cycle time differential signal for the particular cylinder;
comparing the normalized power cycle time differential signal to a misfire threshold signal stored in the memory to determine if the cylinder is misfiring, the misfire threshold signal having a value based on at least one engine operating parameter; and
adaptively modifying the calibration parameter stored in the memory based on the comparison.
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Abstract
An adaptive method of detecting a misfiring cylinder in a spark-ignited internal combustion engine during substantially all engine operating conditions, including most no-load operation. The method includes the step of normalizing an engine acceleration-independent and engine speed-independent power cycle time differential signal for a particular cylinder of the engine, obtained from consecutive power cycle time periods of an engine cycle, utilizing a calibration parameter stored in the memory for the particular cylinder, to obtain a normalized power cycle time differential signal for the particular cylinder. The method also includes the step of comparing the normalized power cycle time differential signal to a misfire threshold signal stored in the memory to determine if the cylinder is misfiring. Preferably, the misfire threshold signal is based on at least one engine operating parameter. The method also includes the step of adaptively modifying the calibration parameter stored in the memory based on the comparison.
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Citations
20 Claims
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1. An adaptive method of detecting a misfiring cylinder in a spark-ignited internal combustion engine controlled by an electronic controller having memory, the method comprising the steps of:
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normalizing an engine acceleration-independent and engine speed-independent power cycle time differential signal for particular cylinder, obtained from consecutive power cycle time periods of an engine cycle, utilizing a calibration parameter stored in the memory for the particular cylinder, to obtain a normalized power cycle time differential signal for the particular cylinder; comparing the normalized power cycle time differential signal to a misfire threshold signal stored in the memory to determine if the cylinder is misfiring, the misfire threshold signal having a value based on at least one engine operating parameter; and adaptively modifying the calibration parameter stored in the memory based on the comparison. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. An adaptive method of detecting a misfiring cylinder in a spark-ignited internal combustion engine controlled by an electronic controller having a memory, the method comprising the steps of:
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obtaining an engine speed-independent percent power cycle time differential signal for a particular cylinder based on consecutive power cycle time periods of an engine cycle; normalizing the engine speed-independent percent power cycle time differential signal based on the average engine acceleration during the engine cycle, to obtain an engine acceleration-independent power cycle time differential signal for the cylinder; normalizing the engine acceleration-independent power cycle time differential signal based on a calibration parameter stored in the memory and associated with the cylinder, to obtain a normalized power cycle time differential signal for the cylinder; comparing the normalized power cycle time differential signal to a misfire threshold signal associated with at least one engine operating condition to determine if the cylinder is misfiring; and adaptively modifying the calibration parameter based on the comparison. - View Dependent Claims (12, 13, 14, 15, 16, 17, 18, 19, 20)
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Specification