Patent ID: 6981653

Claim:
In a fuel injection system for an internal combustion engine, having a high-pressure fuel pump ( 10 ) with a fuel injection valve ( 12 ) connected to it for each cylinder of the engine, wherein the high-pressure fuel pump ( 10 ) has a pump piston ( 18 ) that is driven into a stroke motion by the engine and defines a pump working chamber ( 22 ) that is supplied with fuel from a fuel tank ( 24 ), wherein the fuel injection valve ( 12 ) has a pressure chamber ( 40 ) connected to the pump working chamber ( 22 ) and an injection valve element ( 28 ) that controls at least one injection opening ( 32 ) and the pressure prevailing in the pressure chamber ( 40 ) can act on the injection valve element ( 28 ) in an opening direction ( 29 ) in order to open the at least one injection opening ( 32 ), having a first control valve ( 68 ) that controls a connection ( 66 ) of the pump working chamber ( 22 ) to a relief chamber ( 24 ), and having a second control valve ( 70 ) that controls a connection ( 64 ) of a control pressure chamber ( 52 , 54 ; 152 , 154 ) to a relief chamber ( 24 ), wherein the control pressure chamber ( 52 , 54 ; 152 , 154 ) is defined by a control piston ( 50 ; 150 ), which, when acted on by the pressure prevailing in the control pressure chamber ( 52 , 54 ; 152 , 154 ), acts in a closing direction on the injection valve element ( 28 ) and can move together with the injection valve element ( 28 ), wherein the control pressure chamber ( 52 , 54 ; 152 , 154 ) has a connection ( 62 ) to the pump working chamber ( 22 ), the improvement wherein, in a stroke position of the control piston ( 50 ; 150 ) in which the injection valve element ( 28 ) is in its closed position, the pressure prevailing in the control pressure chamber ( 52 , 54 ; 152 , 154 ) acts on a greater end surface of the control piston ( 50 ; 150 ) than in a stroke position of the control piston ( 50 ; 150 ) in which the injection valve element ( 28 ) is opened by its maximal stroke.