Patent ID: 7032582

Claim:
An injection control system of an internal combustion engine, the injection control system comprising: determining means for determining whether a learning condition for performing an injection quantity learning operation is established; commanding means for performing a single injection from an injector into a specific cylinder of the engine to perform the injection quantity learning operation when the learning condition is established; measuring means for receiving a rotation speed of the engine sensed by a rotation speed sensor as an engine rotation speed and for measuring a rotation speed fluctuation of the engine caused by the single injection based on the engine rotation speed; calculating means for calculating a correction value for increasing or decreasing a command injection quantity, which is outputted to the injector, based on the rotation speed fluctuation of the engine; and correcting means for correcting the command injection quantity by increasing or decreasing the command injection quantity in accordance with the correction value, wherein the measuring means receives the engine rotation speed sensed by the rotation speed sensor in a period from a time point when an exhaust valve opens to a time point when a top dead center of a next cylinder, in which an injection is performed next to the specific cylinder, is detected, and measures the rotation speed fluctuation based on the engine rotation speed.