Patent ID: 8145411

Claim:
An ignition timing control apparatus for an internal combustion engine comprising: a knock sensor detecting a magnitude of vibration of the internal combustion engine in a plurality of ignition cycles; and a control unit, wherein said control unit calculates a first value representing a median value of said magnitude by updating the first value according to said magnitude, calculates a second value representing a standard deviation of said magnitude by updating the second value according to said magnitude, calculates a third value based on said first and second values, calculates a fourth value based on said magnitude and said third value, controls ignition timing of said internal combustion engine according to a result of comparison between said fourth value and a determination value selected from among a predetermined plurality of determination values, determines whether the determination value to be compared with said fourth value is to be changed or not, and updates said first value so that said first value changes faster, when it is determined that the determination value to be compared with said fourth value is to be changed.