Ignition timing control apparatus for internal combustion engine

An ignition timing control apparatus for an internal combustion engine, comprising an electronic control unit configured to

• i) perform determination as to whether knocking has occurred in the internal combustion engine based on a detection signal from a knock sensor;
• ii) update a first learning value that compensates for a change in an ignition timing resulting from a factor other than a time-dependent change in the internal combustion engine, and a second learning value that compensates for a change in the ignition timing resulting from the time-dependent change in the internal combustion engine such that the ignition timing is retarded when the electronic control unit determines that knocking has occurred;
• and
• iii) derive, as a required ignition timing, a timing obtained by retarding a base ignition timing based on the first learning value and the second learning value, wherein
• the electronic control unit is configured to update the second learning value within a range in which an update amount of the second learning value within a prescribed period set in advance does not exceed a prescribed amount, when updating the second learning value.