Fuel injection timing control system for internal combustion engine

Abstract

A fuel injection 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 fuel injection start timing limit by which injection of the determined fuel injection amount should be started and a fuel injection end timing limit by which injection of the determined fuel injection amount should be ended are determined based at least on the detected engine speed in accordance with predetermined data so as to avoid smoke from occurring in the engine, and when a determined fuel injection amount can not be injected within a time of period defined by the limits, a desired fuel injection start or end timing or the determined fuel injection amount is corrected, thereby ensuring the engine torque drop to a minimum extent, while surely avoiding smoke to occur.