| 摘要 |
PROBLEM TO BE SOLVED: To provide a knock control apparatus for an internal combustion engine enabling accurate knock determination level setting without detailed adaptation irrespective of a shape of distribution of knock sensor signal. SOLUTION: A knock control apparatus includes: a knock sensor 4 for detecting knock of the internal combustion engine; a signal processing section 41 for performing frequency analysts of the knock sensor signal by DFT and calculating a knock intensity; and knock determination level setting sections 42, 43: for calculating an average value of the knock intensity; for calculating, based on the average value, an overall variance of the knock intensity of an entirety of a frequency distribution, a higher variance of the knock intensity above the average value, and a lower variance of the knock intensity below the average value; for calculating a standard deviation of the knock intensity from the overall variance; for presetting a value allowing the frequency distribution of the knock intensity to be a predetermined confidence interval as a confidence coefficient; for correcting the confidence coefficient based on the upper variance and the lower variance; and for setting a sum of the average value and a value obtained by multiplying the standard deviation by the corrected confidence coefficient as a knock determination level. COPYRIGHT: (C)2010,JPO&INPIT
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