Robert Boschgmbh

Friedrich Weiss

Nestor Rodriguez-Amaya

Karl Hofmann

Ewald Eblen

Dietrich Trachte

Alfred Schmitt

Jean Pigeroulet

Volker Holzgrefe

Nikolaus Simon

Ewald Ziegler

The invention relates to an electrically controlled injection system for internal combustion engines, in which a magnet valve that is open when without current is used to control the fuel quantity of a high-pressure chamber in the injection pump. A pressure chamber communicates via a pressure conduit directly with the pump work chamber of the high-pressure pump, and a connection from the pressure chamber to a diversion chamber is controlled by a movable valve member via a valve seat. A diversion bore, and a pressure equalization piston is disposed on the valve member, via a neck, on a side remote from the magnet, so that approximately the same pressure as on the magnet side of the movable valve member prevails on the face end of this pressure equalization piston. The chambers on both face ends of the valve member communicate with one another through a connecting conduit, and a further connecting conduit leads from the magnet chamber to a leakage chamber. In one feature of the invention, first and second throttles are disposed upstream of the face end chamber and at the end of the connecting conduit, so that the valve member is embedded in a hydraulic column of equal pressure.

Electrically controlled fuel injection system

The injection pump has a pump piston driven with a constant stroke which pumps fuel at injection pressure to an injection nozzle so long as an electrically actuated overflow valve blocks the flow of the fuel overflowing via an overflow conduit to a low-pressure chamber. The overflow valve is a needle valve, the valve needle of which, opening inward toward a pressure chamber that can be placed under injection pressure, by means of a conical closing surface radially defining a needle tip controls a valve seat that widens conically toward the pressure chamber. The cone angle of the closing surface is larger than the cone angle of the associated valve seat and the closing surface forms a sealing edge, the diameter of which is equal to or only slightly smaller than the guide diameter of the guide shank on the valve member. In a preferred embodiment, the needle tip of the valve member has an external contour on its end, adjacent to the closing surface, which directs the fuel flow and reinforces the opening movement. The injection pump is particularly suitable for high-pressure injection in Diesel engines, in order to attain an exact electrical control of the supply onset and supply quantity, if a reservoir chamber defined by a deflecting piston is connected to a high-pressure chamber that includes the pump work chamber.

Electrically controlled fuel injection pump for internal combustion

Growing community of inventors

Korntal-Muenchingen, Germany

Friedrich Weiss