Fuel injection system for internal combustion engine

A fuel injection control system for an internal combustion engine comprising:

• crank angle detecting means for detecting a crank angle;
• synchronous-injection means for performing synchronous injection of a fuel into an intake manifold for each cylinder in synchronism with the crank angle detected by said crank angle detecting means;
• intake valve closure timing detecting means for detecting a crank angle corresponding to closure of an intake valve of each cylinder of the engine, in advance;
• asynchronous injection means for performing asynchronous injection of fuel into the intake manifold of each cylinder upon at least one of engine starting state and acceleration state;
• asynchronous injection crank angle computing means for determining crank angles at initiation of an asynchronous injection of fuel and termination of the asynchronous injection before initiation of said asynchronous injection to be performed by said asynchronous injection means;
• injected fuel division checking means for checking whether fuel amount of the asynchronous injection performed by said asynchronous injection means is divided or not by the closure of the intake valve caused at the crank angle detected by said intake valve closure timing detecting means in advance and said crank angles determined by said asynchronous injection crank angle computing means;
• and
• first fuel injection control means for inhibiting fuel injection when said injected fuel division checking means detects a division of the fuel amount.