US 4,903,666 AGranted

Fuel injection device

AssigneeRobert Bosch GmbH

InventorsDominique Buisson, Francois Henry, Jean Leblanc, Helmut Pfeifle, Jean Pigeroulet

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Abstract

A fuel injection device having a pump piston which during the supply stroke pumps fuel from a pump work chamber into an injection line which leads to a fuel injection valve. Directly adjacent to the branching off of the injection line from the pump work chamber, at the diameter of the injection line, a valve seat is provided, at which the injection line then merges with a chamber into which a pressure valve closing member plunges. The valve closing member is tightly guided in a guide bore, loaded by a valve spring, and in the chamber has a pressure shoulder adjoining the sealing surface that cooperates with the valve seat. The rear side of the pressure valve closing member communicates with a continuously open relief line. Because of this construction, the pressure valve closing member operates as an equal-pressure valve and simultaneously as a deflecting piston as well, with the aid of which a pressure rise in the pump work chamber is built up in a retarded manner until such time as the pressure valve closing member comes to rest on a stop. A pressure rise of this type is particularly advantageous in connection with control of the injection phase by means of a magnetic valve subjected to the high pressure.

Claims9

Dependent claims

A fuel injection device for internal combustion engines, comprising:

a pump housing that receives a pump cylinder and a reciprocally driven pump piston being guided therein;
a pump work chamber defined by said pump piston within said pump cylinder;
a fuel injection value;
a fuel injection line connectable at its one end to said fuel injection valve, which fuel injection line is arranged to be made to communicate with said pump work chamber at its other end;
a pressure valve having a pressure valve closing member guided tightly in a guide cylinder, which pressure valve closing member defining at its rear side a spring chamber receiving a first spring to act upon said valve closing member, means for connecting said spring chamber with a relief chamber, said valve closing member further being arranged to cooperate with stop means to thereby define the stroke of said valve closing member in said guide cylinder, said valve closing member further having a front side forming a sealing face matching with a valve seat which defines a flow cross section of said injection line, said front side further forming a pressure shoulder joining said sealing face and defining part of a chamber, which chamber is permanently connected to a part of said injection line between said injection valve and said valve seat;
and
a control valve;
said control valve includes an electrically controlled valve, said electrically controlled valve includes a closing member which cooperates with a valve seat defining a flow cross section in said relief conduit, said relief conduit communicates at one end with said work chamber and at its opposite end with a fuel supply source which, during the intake stroke of the pump piston, communicates with the pump work chamber via the relief conduit.

5 more elements

A fuel injection device for internal combustion engines, comprising:

a pump housing that receives a pump cylinder and a reciprocally driven pump piston being guided therein;
a pump work chamber defined by said pump piston within said pump cylinder;
a fuel injection valve;
a fuel injection line connectable at one end to said fuel injection valve, which fuel injection line is arranged to be made to communicate with said pump work chamber at its other end;
a pressure valve having a pressure valve closing member guided tightly in a guide cylinder, work chamber at its other end;
member defining at its rear side a spring chamber receiving a first spring to act upon said valve closing member, means for connecting said spring chamber with a relief chamber, said valve closing member further being arranged to cooperate with stop means to thereby define the stroke of said valve closing member in said guide cylinder, said valve closing member further having a front side forming a sealing face matching with a valve seat which defines a flow cross section of said injection line, said front side further forming a pressure shoulder joining said sealing face and defining a part of a chamber, which chamber is permanently connected to a part of said injection line between said injection valve and said valve seat, and in the closing position of said pressure valve closing member, communication is established between said pump work chamber and said injection line which leads to said fuel injection valve, at least before the onset of the effective supply stroke of said pump piston;
and
a control valve (flow cross section control valve) to provide communication between said pump work chamber an a relief conduit upon the end of the effective supply stroke of said pump piston.

5 more elements

Dependencies are inferred from the claim text.

Facts

Application: 07/281,144Filed 6 Dec 1988 · division
Priority: DE 352142714 Jun 1985
Granted: 27 Feb 1990
Term ends: Not estimatedThe source records don’t support an estimate.

Classification9 codes

F02M 57/02
Fuel-injectors combined or associated with other devices: injectors structurally combined with fuel-injection pumps
F02M 55/04
Fuel-injection apparatus characterised by their fuel conduits or their venting means; Arrangements of conduits between fuel tank and pump…
F02M 59/366
By variably-timed valves controlling fuel passages to pumping elements or overflow passages: valves being actuated electrically
F02M 59/462
Valves: delivery valves