Fluid sprinkling – spraying – and diffusing – Including valve means in flow line – Reciprocating
Reexamination Certificate
2000-01-19
2001-12-11
Scherbel, David A. (Department: 3752)
Fluid sprinkling, spraying, and diffusing
Including valve means in flow line
Reciprocating
C239S533200, C239S533900, C239S584000, C239S575000, C239S585300, C239SDIG002
Reexamination Certificate
active
06328232
ABSTRACT:
TECHNICAL FIELD
This invention relates to engine fuel injectors, particularly of the solenoid actuated top feed type, and more particularly to an injector having an inlet fuel filter mounted within a frictionally retained valve spring calibration tube.
BACKGROUND OF THE INVENTION
It is known in the art to provide an engine top feed fuel injector with a fuel inlet filter mounted within the fuel inlet tube. It is further known to provide a calibration tube which is slidable within the inlet tube for adjusting the force on a solenoid actuated fuel inlet valve and to propose a fuel filter mounted on the outer end of the calibration tube.
In this proposal, the calibration tube is adjusted by a tool which engages the closed outer end of the filter and forces it down with the tube until the desired valve spring force is achieved. The calibration tube is then fixed to the inlet tube by any suitable means to hold the calibration tube in place. The friction force of the tube by itself is inadequate to maintain the set calibration tube position since adjustment of the tube by applying a force to the filter body requires that the sliding force of the calibration tube be limited to an amount which the plastic body of the filter is able to withstand, preferably not more than about two pounds. Also, the low force sliding fit of the calibration tube in the fuel inlet tube allows fuel carrying contaminant particles up to 100 microns in diameter to bypass the filter by passing through clearance spaces between the tubes. It is accordingly desired to provide a calibration tube mounted inlet filter which overcomes the problems of the prior art.
SUMMARY OF THE INVENTION
The present invention provides a fuel injector having a fuel tube at the inlet end and an injection valve at the discharge end of the injector, the valve including a valve element reciprocable against and away from a valve seat. A biasing spring operatively engages the valve element, optionally through a solenoid-actuated armature, and a calibration member or tube is adjustable within the injector to establish a set force of the valve biasing spring.
A fuel filter is mounted within the calibration member, preferably in a manner to allow direct engagement of a calibration tool with the outer end of the calibration member for adjusting the spring force. The fuel filter is preferably mounted in the calibration tube with an interference fit that is adequate to maintain the set position by friction between the members without requiring an additional securing step. Optionally, the calibrating tool may engage a base or mounting portion of the filter body snap fitted or otherwise mounted in a calibration tube. In any case, a force adequate to provide the desired interference fit may be applied to the calibration tube without passing through the complete filter body. Preferably, the interference fit is also sufficient to prevent the bypassing of fuel past the calibration tube and around the filter so as to prevent particles larger than the filter is designed to remove from remaining in the fuel stream. Thus, the filter and the interference fit may be selected to capture particles greater than about 30 microns in diameter.
These and other features and advantages of the invention will be more fully understood from the following description of certain specific embodiments of the invention taken together with the accompanying drawings.
REFERENCES:
patent: 4218021 (1980-08-01), Palma
patent: 5494224 (1996-02-01), Hall et al.
patent: 5755386 (1998-05-01), Lavan et al.
patent: 5921475 (1999-07-01), DeVriese et al.
patent: 5937887 (1999-08-01), Baxter et al.
patent: 5979866 (1999-11-01), Baxter et al.
patent: 6019128 (2000-02-01), Reiter
Haltiner, Jr. Karl Jacob
Perry Robert B.
Sofianek Jay Keith
Wendt Peter Ronald
Delphi Technologies Inc.
Evans Robin O.
Scherbel David A.
VanOphem John A.
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