Abstract: A method and system to determine the borderline spark timing for a given speed and load of a given cylinder and control spark timing relative to that borderline spark timing to maintain the torque/efficiency of the engine. The system measures combustion related events at several steps from a retarded spark timing to a spark timing signal which is calculated to be beyond the borderline spark timing value. From these measurements, the borderline spark timing signal for a given cylinder at a given speed and load is determined and saved. Borderline spark timing is the spark timing at which audible knock starts to occur.

Abstract: A method is provided for controlling knock in an internal combustion engine. The method utilizes an adaptive control scheme to tailor knock thresholds to the current engine operating conditions, as well as to identify the cylinder in which the knocking condition occurred. The method utilizes a modified spark advance to alter the spark timing for the engine cylinders if a knocking condition is detected and a predetermined set of conditions has been met.