Patent ID: 6446606
Filing Date: 2002-09-10
Classification: F02M

Abstract:
A fuel injection system for internal combustion engines, comprising a distributor tube and a high-pressure pump that is driven as a function of engine rpm and that serves to generate the fuel pressure and throughput required in the distributor tube in the applicable operating state of the engine, and also a fuel metering unit, which is associated with the high-pressure pump, the fuel metering unit being disposed in the high-pressure pump and having a regulating valve actuated by an electromagnet, the regulating valve comprising a valve housing (22) provided with an inlet communicating with the compression side of a prefeed pump and an outlet discharging into the low-pressure region of the high-pressure pump, the regulating valve further comprising a valve piston (25), which is biased by a compression spring (27) to an open position and which is movable to a closed position by an armature bolt (14) of the electromagnet, the electromagnet including a housing and the regulating valve axially adjoins the housing of the electromagnet, the regulating valve housing having an end face with an axial opening (31), at least one radial control opening (32, 34, 35) being disposed in a wall of the valve housing (22) and being exposed by movement of the valve piston, the movement of the valve piston being divided into two distinct regions, the at least one radial control opening being shaped and/or disposed such that during one region of the stroke of the valve piston, the opening area of the control opening which is exposed changes slowly, and in the other region of the stroke of the valve piston the opening area of the control opening which is exposed changes more rapidly and the axial opening in the end face of the valve housing communicating with one of the compression side of a prefeed pump and the low-pressure region of the high-pressure pump and the at least one control opening communicating with the other of the compression side of a prefeed pump and the low-pressure region of the high-pressure pump.