Patent ID: 6959694

Claim:
In a fuel injection system for an internal combustion engine, having a high-pressure pump ( 18 ), by which fuel is pumped at high pressure into a reservoir ( 32 ) with which injectors ( 40 ) disposed on the cylinders of the engine communicate, having a feed pump ( 10 ), by which fuel is pumped from a tank ( 12 ) to the high-pressure pump ( 18 ), and the high-pressure pump ( 18 ) has at least one pump element ( 22 ) with a pump piston ( 26 ) that defines a work chamber ( 34 ) and is driven in a reciprocating motion, and the work chamber ( 34 ) has a communication with the compression side of the feed pump ( 10 ), in which communication an intake valve ( 36 ) opening toward the work chamber ( 34 ) is disposed, by which valve upon the intake stroke of the pump piston ( 26 ) fuel flows into the work chamber ( 34 ), and the intake valve ( 36 ) has a valve member ( 76 ), acted upon in a closing direction by a closing spring ( 80 ), and the closing spring ( 80 ) is braced at least indirectly on the pump piston ( 26 ), and with an increasing intake stroke of the pump piston ( 26 ), the closing force is exerted on the valve member ( 76 ) by the closing spring ( 80 ) becomes less, the improvement wherein a minimal opening differential pressure of the intake valve ( 36 ) amounts to less than 0.9 bar.