Patent ID: 7281516

Claim:
An ignition timing control device of an internal combustion engine, said device comprising: a knock magnitude calculating portion for calculating knock magnitude related to magnitude of vibration due to knocking based on magnitude of vibration occurring in said internal combustion engine; a control portion for controlling ignition timing of said internal combustion engine based on a result of comparison between said knock magnitude and a predetermined determination value; a waveform detecting portion for detecting a waveform of the vibration occurring in said internal combustion engine at predetermined intervals; a memory portion for storing a waveform which is a standard of the vibration of said internal combustion engine; a detecting portion for detecting magnitude values related to the magnitude of the vibration occurring in said internal combustion engine in a plurality of ignition cycles; an extracting portion for extracting a magnitude value satisfying a predetermined first condition from said plurality of magnitude values based on a result of comparison between said detected waveform and said stored waveform; a correcting portion for correcting said predetermined determination value based on said extracted magnitude value; and a prohibiting portion for prohibiting correction of said predetermined determination value when a predetermined second condition is satisfied.