DUAL FUEL INJECTION SYSTEM INTERNAL COMBUSTION ENGINE

To simply prevent an internal combustion engine including PFI and DI injectors from generating of knocking phenomenon, the internal combustion engine includes an engine control unit (ECU) for setting a ratio of fuel injection quantity of both the injectors (Step S2). The ECU includes a memory storing four sheets of ignition timing maps, with reference to which the maximum torque generation timing and knocking limit torque generation timing, at the direct injection injector (100%) and port fuel injection injector (100%), are calculated (Step S3). The ECU further operates to calculate a correction amount from correction amount map (Step S4). The ECU calculates first interpolation value of the maximum torque generation timing at the above 100% operation time of both the injectors and second interpolation value of the knocking limit torque generation timing at the above 100% operation time of both the injectors, and a value in which the correction amount is added to either one of the above first and second interpolation value on a delay angle side is calculated as ignition timing (Step S5).