Patent ID: 7681552

Claim:
A knock determination device for an internal combustion engine, comprising: a knock sensor detecting vibration intensity of said internal combustion engine in an interval of predetermined crank angles; and an operation unit; wherein said operation unit detects a waveform of vibration of said internal combustion engine based on the vibration intensity of said internal combustion engine, calculates a first value corresponding to the vibration intensity of said internal combustion engine, calculates, based on a result of comparison between said detected waveform and a predetermined waveform model as a reference waveform of vibration in said internal combustion engine, a second value corresponding to a difference between said detected waveform and said waveform model, determines whether or not knock has occurred in said internal combustion engine based on a result of comparison between said first value and a predetermined first determination value, and based on a result of comparison between said second value and a predetermined second determination value, corrects said first determination value if the number of first values not lower than said first determination value is not smaller than a first number, among the first values calculated in a plurality of predetermined number of continuous ignition cycles, and corrects said first determination value if the number of first values not lower than said first determination value is not smaller than a second number, among the first values calculated in a plurality of ignition cycles in which said second value satisfies a predetermined condition.