Patent ID: 6568927
Filing Date: 2003-05-27
Classification: F02M,F04B

Abstract:
A piston pump (6) including a plurality of pump elements (7) for supplying fuel at high pressure in fuel injection systems of internal combustion engines, in particular in a common rail injection system, whereinthe pump elements (7) are connected on the intake side to a pump (1) that pumps fuel at low pressure in a regulated quantity, each pump element (7) is preceded on the intake side by a first check valve (10), with which the supply of fuel into a cylinder chamber (9) of the pump element (7), which chamber has a pump piston (8), is controllable, the first check valve (10) opens counter to spring force in the intake phase of the pump element (7) and closes in the pumping phase, and wherein a second check valve (11) precedes the first check valve (11) on the inflow side; and the second check valve (11) opens counter to spring force and closes, reinforced by spring force, at pressures of the fuel supplied by the pump (1) that are higher than the negative pressure generated in a cylinder chamber (9) of the pump element (7).