Ignition timing control system for internal combustion engine

Abstract

An ignition timing control system for a direct injection spark ignition internal combustion engine which is operated at an ultra-lean burn combustion or at a pre-mixture charged combustion. In the system, a desired fuel injection end timing at which injection of the determined fuel injection amount should be ended is determined. Then, the difference between the desired fuel injection end timing and the ignition timing is calculated and is determined whether the difference is less than a predetermined value (crank angle margin), and the ignition timing is corrected by the predetermined value when the difference is determined to be less than the predetermined value, thereby enabling to prevent the overlapping of the fuel injection end timing and the ignition timing from happening and avoiding the problem of misfiring or residual of unburned fuel in the cylinder from occurring.