A delivery valve for use in a fuel injection system of an internal combustion engine comprises a valve body defining a bore in which is slidably mounted a valve member which is biased towards one end of the bore by a coiled compression spring. A first circumferential groove in the bore communicates with the one end of the bore and a second groove on the valve member communicates with the first groove and is exposed beyond the other end of the bore when the valve is opened to allow fuel flow past the valve. The valve member is moved by fuel pressure at the one of the bore and the extent of movement of the valve member against the action of the spring is limited.

A fuel injection pump which has a shutoff device for the fuel supply to the pump work chamber, comprising a magnetic valve, which controls an intake bore to the work chamber of the fuel injection pump. The fuel injection pump further has a relief conduit, which is connected by an annular slide on the pump piston with the suction chamber in order to terminate the effective supply stroke of the pump piston. In order to assure reliable shutoff of the fuel supply to the pump work chamber, a check valve is further disposed in the connection between the pump work chamber and the suction chamber, which check valve is closed, during the intake stroke of the pump piston, with the collaboration of the pressure drop from the suction chamber to the pump work chamber.

A high pressure fuel system includes a combination bypass and safety pressure release valve across the high pressure fuel pump. The combination valve allows the feed pump to directly provide fuel to the system before the high pressure pump reaches full output pressure. The valve also releases overpressure in the system when the high pressure pump is deadheaded. The combination valve includes a check ball which allows fuel to flow from its input to its output when the pressure is greater at its input than at its output.

A liquid fuel injection system with a snubber valve assembly with a low cost, four-part snubber valve mounted within a valve body and in addition in a second embodiment a low cost, two-part fuel pressurizing valve mounted within the valve body upstream of the snubber valve.

In a pressure valve inserted in a fuel supply conduit between a fuel injection pump and an injection vavle of the internal combustion chamber and comprising a valve member and a locking member cooperating with the valve member and opening in the direction of the fuel supply, and a back-pressure relief valve including a closing element which closes an axial bore of the locking member, a throttle orifice is provided in the connection between the axial bore of the locking member and an axial recess formed in the connection element connected to the fuel supply conduit leading to the internal combustion engine so that no after-injections occur, and a sufficiently great stable pressure is maintained in the fuel supply system.