an internal combustion engine that can be operated in compression ignition mode , comprising a fuel injector for each cylinder ; a fuel injection control unit for controlling fuel injection quantity and a piston in each cylinder whose compression action causes a mixture of air and fuel to be ignited . the engine is further provided with inlet and outlet valves and sensors for measuring various engine operating parameters , is disclosed . during compression ignition mode , the control unit controls the fuel injector to perform a first fuel injection before , and a second fuel injection after top dead center of the piston stroke during or after a negative valve overlap period . a method for operating the engine and a computer readable storage device having stored therein data representing instructions executable by a computer to implement a compression ignition for an internal combustion engine is also described .