Method and apparatus for controlling a fuel injection system with an intake manifold injector and a direct injection injector

In an internal combustion engine, it is first determined whether a load factor of the internal combustion engine is a specified value or more and the engine speed of the internal combustion engine is a specified speed or less. If these conditions are satisfied, fuel is injected from both of a port injection valve (2) and a direct injection valve (3), and a fuel injection timing of the direct injection valve (3) is decided so as to inject fuel from the direct injection valve (3) during the compression stroke of the internal combustion engine.