Patent ID: 8433497

Claim:
A fuel injection control apparatus which calculates a fuel injection quantity on the basis of a working state of an internal combustion engine, and adjusts fuel supply of fuel injection valves into corresponding cylinders of the internal combustion engine on the basis of a fuel injection pattern which is made on the basis of the calculated fuel injection quantity, the fuel injection control apparatus comprising: fuel injection pattern changing means which changes the fuel injection pattern during a predetermined time period when a learning condition is established during the working of the internal combustion engine; working state change value calculating means which compares the working state of the internal combustion engine (a) when the fuel injection pattern changing means changes the fuel injection pattern of the fuel injection valves with the working state of the internal combustion engine (b) when the fuel injection pattern changing means does not change the fuel injection pattern of the fuel injection valves, in order to calculate a change value of the working state of the internal combustion engine which is generated by the change of the fuel injection pattern by the fuel injection pattern changing means; and learning data calculating means which estimates a change value of the fuel injection quantity which is generated when the fuel injection pattern changing means changes the fuel injection pattern on the basis of the change value of the working state of the internal combustion engine calculated by the working state change value calculating means, and the learning data calculating means which calculates a difference value between the estimated change value of the fuel injection quantity and a reference change value corresponding to the change of the fuel injection pattern, as a learning data item to be used to correct the fuel injection quantity of the fuel injection valves, wherein the fuel injection pattern changing means detects that the learning condition is established when the working state of the internal combustion engine is stable without a transition state, and the fuel injection pattern changing means adds a fuel injection to be performed before or after a main fuel injection in order to change the fuel injection pattern when the detection result indicates that the learning condition is established.