Internal-combustion engines – Charge forming device – Fuel injection system
Reexamination Certificate
1999-06-30
2001-02-13
Moulis, Thomas N. (Department: 3747)
Internal-combustion engines
Charge forming device
Fuel injection system
Reexamination Certificate
active
06186122
ABSTRACT:
FIELD OF THE INVENTION
This invention relates generally to fuel injectors of the type that are used to inject liquid fuel into the induction system of an internal combustion engine, and particularly to a means for restricting movement of the o-ring on an injector.
BACKGROUND OF THE INVENTION
An objective of a fuel injector is to accurately deliver fuel to an associated engine or combustion chamber. A control valve controls the injection start and finish by controlling the intake channel of an injection pump. The control valve is provided with a valve body which is in the form of a piston valve and is provided with a valve seat, with a high pressure chamber and a low pressure chamber, respectively, being provided on the two sides of the valve seat. To deliver the predetermined correct quantity of fuel for each combustion event, it is expected that the valve will open and then close precisely.
It is desirable to restrict the movement of the top external o-ring to prevent the o-ring from falling out of the injector during later stages of injector assembly, test, packaging and shipping, as well as during engine assembly and engine servicing. In some current injectors, a retainer is molded simultaneously with the injector body mold. The retainer is used to restrict the movement of the top external o-ring in providing a static seal between the injector and the fuel rail assembly. The retainer is molded around the inlet tube at the top of the injector. Unfortunately, various problems with production mold flash have created a need for a design alternative for the retainer. Once such alternative is to use a metal retainer which is crimped after installation. However, the design and assembly processes of certain injectors types do not readily allow such crimping operation.
It is seen then that there exists a need for a retainer for a fuel injector which is flexible for installation and robust for injector application.
SUMMARY OF THE INVENTION
This need is met by the snap-lock retainer according to the present invention, wherein the retainer is injection molded as a separate component to eliminate the problem of uncontrollable mold flash.
In accordance with one embodiment of the present invention, a fuel injector assembly comprises a fuel injector having an inlet end and an outlet end, and further having an associated fuel rail assembly. An o-ring seal is located approximately at the inlet end to prevent fluid from leaking out of the fuel injector and the fuel rail assembly. A groove in the inlet end is located above the o-ring seal, and a retainer member is constructed to be received into the groove to provide positional constraint to the o-ring seal.
The present invention also provides a method for fabricating a fuel injector assembly. First, a fuel injector body is provided, housed in a fuel injector housing, the fuel injector body having an inlet end and an outlet end. An o-ring seal is located approximately at the inlet end to prevent fluid from leaking out of the fuel injector. A mating component is formed in the inlet end of the fuel injector housing, above the o-ring seal. Finally, a retainer member is received into the mating component to provide positional constraint to the o-ring seal.
For a full understanding of the nature and objects of the present invention, reference may be had to the following detailed description taken in conjunction with the accompanying drawings and the appended claims.
REFERENCES:
patent: 5301647 (1994-04-01), Lorraine
patent: 5724946 (1998-03-01), Franchitto
patent: 5752487 (1998-05-01), Harrell et al.
patent: 6019089 (2000-02-01), Taylor et al.
Moulis Thomas N.
Siemens Automotive Corporation
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