Patent ID: 7831377

Claim:
An ignition timing control system for an internal combustion engine, comprising: in-cylinder pressure-detecting means for detecting pressure in a cylinder of the engine as in-cylinder pressure; crank angle position-detecting means for detecting a crank angle position of the engine; largest in-cylinder pressure angle-calculating means for calculating a crank angle position at which the in-cylinder pressure becomes largest as a largest in-cylinder pressure angle, based on the detected in-cylinder pressure and crank angle position; target angle-setting means for setting a target angle serving as a target of the largest in-cylinder pressure angle; combustion state parameter-calculating means for calculating combustion state parameters indicative of a combustion state in the cylinder, other than the largest in-cylinder pressure angle, based on the in-cylinder pressure and the crank angle position; combustion mode-determining means for determining whether a combustion mode is an intense combustion mode or a weak combustion mode, based on a plurality of kinds of the calculated combustion state parameters including the largest in-cylinder pressure angle; and ignition timing-calculating means for calculating ignition timing, when the determined combustion mode is the intense combustion mode, such that the calculated largest in-cylinder pressure angle converges to the set target angle, and when the determined combustion mode is the weak combustion mode, by feedback, based on the target angle and the calculated combustion state parameters.