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KNOCK DETERMINATION APPARATUS FOR INTERNAL COMBUSTION ENGINE

  • US 20160123249A1
  • Filed: 11/02/2015
  • Published: 05/05/2016
  • Est. Priority Date: 11/04/2014
  • Status: Active Grant
First Claim
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1. A knock determination apparatus for an internal combustion engine including an in-cylinder pressure sensor that is installed in each cylinder and detects an in-cylinder pressure,wherein the knock determination apparatus is configured to:

  • calculate a knock intensity that is a signal intensity in a predetermined frequency band including a knock frequency band, based on an output signal from the in-cylinder pressure sensor in a predetermined crank angle range;

    determine that when the knock intensity calculated by the knock determination apparatus is larger than a knock determination threshold value, knock has occurred;

    calculate an integrated intensity that is an integrated value of knock intensities that are equal to or larger than a predetermined knock intensity threshold value among knock intensities that are calculated at a respective cycles during a predetermined plurality of cycles in a same cylinder; and

    correct the knock determination threshold value so that a difference between the integrated intensity calculated by the knock determination apparatus and a target integrated intensity becomes small,wherein the predetermined knock intensity threshold value is a knock intensity in a boundary of top predetermined percentage out of knock intensities included in a frequency distribution showing a relation between the knock intensities acquired in the predetermined plurality of cycles when an internal combustion engine is operated in a state in which a knock level specified in accordance with a knock intensity and a knock frequency is a target knock level, and calculation frequencies of a respective knock intensities, andwherein the target integrated intensity is an integrated value of knock intensities that are equal to or larger than the knock intensity threshold value that are extracted from the knock intensities which are acquired in the predetermined plurality of cycles when the internal combustion engine is operated in the state in which the knock level is the target knock level.

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