FUEL INJECTION CONTROL DEVICE OF INTERNAL COMBUSTION ENGINE

In a compression self-igniting internal combustion engine in which fuel injected into a cylinder from a fuel injection valve combusts in the cylinder, and which can perform a main injection for main combustion and an auxiliary injection executed prior to the main injection, as operations of fuel injection from the fuel injection valve, a fuel injection amount of the auxiliary injection is obtained from a preheating combustion fuel amount for realizing a required ignition temperature of the main combustion and a premixed combustion fuel amount for reducing exhaust emissions. Then, a preheating combustion period is obtained based on the preheating combustion fuel amount in accordance with an in-cylinder gas state and/or a fuel spray state, and an injection time of the auxiliary injection is determined based on the preheating combustion period and a required ignition time of the main combustion, so that an end time of the preheating combustion period matches the injection time of the main combustion. Determining the injection time of the auxiliary injection in this manner ensures an appropriate preheating amount and appropriate premixed combustion for the ignition time of the main combustion even during a transitional period of operation and the like.