Pressure booster for a fuel injection system

A pressure booster (9a;

• 9b;
• 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 (10a, 10b, 57;
• 68)
• a displaceable piston unit (30a, 31a;
• 30b, 31b;
• 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 (30a, 31a;
• 30b, 31b;
• 52, 53;
• 66) having a third piston cross section, which is reduced compared to the first piston cross section, disposed in the differential chamber (10a;
• 10b;
• 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 (10a;
• 10b;
• 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 (30a, 31a;
• 31a, 31b;
• 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 (10a;
• 10b;
• 57;
• 68), when the pressure booster (9a;
• 9b;
• 51;
• 61) is not activated, are filled with fuel that is at system pressure.