Patent ID: 6443129
Filing Date: 2002-09-03
Classification: F02M

Abstract:
In a pressure booster for a fuel injection system for internal combustion engines, in which the pressure booster has a stepped piston (5) which is displaceable in a bore (18) and whose end faces (7, 9) each define one pressure chamber (1, 3); in which a first, larger end face (7) of the stepped piston (5) defines a first pressure chamber (1), which can be made to communicate with a high-pressure reservoir (25), and a second, opposed, smaller end face (9) of the stepped piston (5) defines a second pressure chamber (3), communicating with an injection nozzle (21); and in which, in transitioning from the larger end face 7 to the smaller end face 9, a cross-sectional change (11) of the stepped piston (5) is produced, which, in cooperation with a shoulder (13) in a housing (15) of the pressure booster define a relief chamber (17), the improvement wherein the first pressure chamber (1) and the relief chamber (17) can be made to communicate hydraulically with one another, wherein between the high-pressure reservoir (25), first pressure chamber (1) and relief chamber (17), a control valve (23) is disposed, which hydraulically disconnects the high-pressure reservoir (25) from the relief chamber (17) or disconnects both the high-pressure reservoir (25) from the relief chamber (17) and the first pressure chamber (1).