Patent ID: 7025284

Claim:
In a fuel injection system for an internal combustion engine, having a high-pressure fuel pump ( 10 ) and a fuel injection valve ( 12 ) connected to it for each cylinder of the engine, the high-pressure fuel pump ( 10 ) having a pump piston ( 18 ) that is driven into a stroke motion by the engine and delimits a pump working chamber ( 22 ), which is supplied with fuel from a fuel tank ( 24 ), the fuel injection valve ( 12 ) having 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 ) counter to a closing force 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 ) to a relief chamber ( 24 ), wherein the control pressure chamber ( 52 ) is delimited by a control piston ( 50 ), which, due to the action of the pressure prevailing in the control pressure chamber ( 52 ), acts in a closing direction on the injection valve element ( 28 ) and can move in concert with the injection valve element ( 28 ), wherein the control pressure chamber ( 52 ) has a connection ( 62 ) to the pump working chamber ( 22 ), the improvement comprising a throttle restriction ( 63 , 65 ) is respectively provided in the connections ( 62 , 64 ) of the control pressure chamber ( 52 ) to the pump working chamber ( 22 ) and to the relief chamber ( 24 ), and an additional pressure chamber ( 54 ) connected to the pump working chamber ( 22 ) and delimited by a pressure surface ( 53 ) that is used to exert an additional force on the injection valve element ( 28 ) in the closing direction.