Patent ID: 6883498

Claim:
A pressure booster ( 9 a ; 9 b ; 51 ; 61 ) of a fuel injection system ( 1 ), comprising a pressure booster chamber having a low pressure side ( 13 ; 67 ), a high pressure side ( 12 ) and a differential chamber ( 10 a , 10 b , 57 ; 68 ) a displaceable piston unit ( 30 a , 31 a ; 30 b , 31 b ; 52 , 53 ; 66 ), disposed in the pressure booster chamber and having a first cross section on one end which can be subjected to pressure via the low pressure side ( 13 ; 68 ) of the pressure booster chamber and a second cross section on its other end subjected to pressure in the high pressure side ( 12 ) of the pressure booster chamber for fuel compression, the piston unit ( 30 a , 31 a ; 30 b , 31 b ; 52 , 53 ; 66 ) having a third piston cross section, which is reduced compared to the first piston cross section, disposed in the differential chamber ( 10 a ; 10 b ; 57 ; 68 ), the differential chamber being connectable to a leak fuel line ( 16 ), and at least one control conduit ( 33 , 35 ; 54 , 55 ; 62 , 64 ) connecting the pressure booster chamber ( 13 ; 67 ) on the low-pressure side to the differential chamber ( 10 a ; 10 b ; 57 ; 68 ), the at least one control conduit having an opening that is closed or opened as a function of the motion of at least parts of the piston unit ( 30 a , 31 a ; 31 a , 31 b ; 52 , 53 ; 66 ), the pressure booster chamber ( 13 ; 67 ) on the low-pressure side, the pressure booster chamber on the high-pressure side, and the differential chamber ( 10 a ; 10 b ; 57 ; 68 ), when the pressure booster ( 9 a ; 9 b ; 51 ; 61 ) is not activated, are filled with fuel that is at system pressure.