System, method and computer program for controlling fuel injection in a diesel engine

Fuel injection system for suppressing smoke exhausted from a diesel engine is provided. A fuel injector (5) is controlled to inject fuel near top dead center of a compression stroke in such a divided manner that the injected fuel combust continuously, wherein the first injection starts prior to top dead center of a compression stroke, and the second injection starts after timing that the firstly injected fuel is calculated to start firing, thereby the firstly injected fuel increases the chamber temperature to promote combustion of the secondly injected fuel.