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Adaptive method of cylinder misfire detection in an internal combustion engine

  • US 5,237,862 A
  • Filed: 06/22/1992
  • Issued: 08/24/1993
  • Est. Priority Date: 06/22/1992
  • Status: Expired due to Fees
First Claim
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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:

  • 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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