Fluid sprinkling – spraying – and diffusing – Including valve means in flow line – Reciprocating
Utility Patent
1999-06-09
2001-01-02
Weldon, Kevin (Department: 1734)
Fluid sprinkling, spraying, and diffusing
Including valve means in flow line
Reciprocating
Utility Patent
active
06168098
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to needle type solenoid operated fuel injectors for controlling the injection of fuel into an internal combustion engine and more particularly to a fuel injector for direct injection of fuel into the engine.
BACKGROUND OF THE INVENTION
It is known in the fuel injection art to utilize a needle within a solenoid operated fuel injector to close a fuel passageway in a valve seat. In such injectors, a pierced hole thin lower guide aligns and supports the needle during movement. The pierced hole typically has a breakout which leaves a very small (thin) guide surface. Also, the needle has occasion to wear due to the sharp thin punched hole. This wear reduces alignment, allows fuel flow around the needle and may, initiate or contribute to fuel leakage. Misalignment results in the needle striking the cone of the sealing surface and sliding along the cone edge before being guided into the seal position and closing the flow port. Friction between the needle and the cone delays closing and disrupts the uniform spray pattern prior to complete shut off. A similar delay in developing a uniform spray pattern occurs as the needle is lifted out of the seal position.
SUMMARY OF THE INVENTION
The present invention provides a solenoid actuated fuel injector having improved axial alignment of a needle with a valve seat, reducing initial and long term leakage, resulting in improved manufacturing yield and extended life durability.
According to the invention, the solenoid actuated fuel injector comprises a valve body having a longitudinal axis. A valve seat subassembly is mounted in one end of the valve body. The valve seat subassembly includes a valve seat having a seating surface and a circumferential sealing surface surrounding the seating surface. The sealing and seating surfaces face the interior of the valve body. The seating surface includes a fuel outlet opening centered on the axis and in communication with means for conducting pressurized fuel into the valve body against the seating surface.
A needle having an end is moveable between a seated position, wherein the end is urged against the seating surface to close the outlet opening against fuel flow, and an open position, wherein the end is spaced from the seating surface to allow fuel flow through the outlet opening. Biasing means in the valve body is provided for biasing the needle toward the seated position.
The valve seat subassembly also includes a lover needle guide. The lower needle guide includes a flange portion and a tube portion having an axially disposed tubular bore for guiding the needle. The tubular bore provides a longer length interface with the needle and a smoother wear surface than a conventional pierced hole thin lower guide.
The lower guide also includes a plurality of fuel flow holes in the flange spaced around the tubular bore. The tube portion extends from the flange toward the inside of the valve body.
In an exemplary embodiment, a swirl disk is sandwiched between the valve seat sealing surface and the lower guide flange. The swirl disk receives fuel from the plurality of fuel flow holes in the lower guide flange and distributes the fuel to the valve seat fuel outlet opening.
The valve seat subassembly can be assembled on a weld guide that aligns the valve seat, swirl disk, and lower guide against a shoulder in the end of the valve body, and the nose of the valve body is crimped to hold the seat subassembly in the valve body and the valve seat is laser welded in the end of the valve body mounting the subassembly therein.
REFERENCES:
patent: 4597558 (1986-07-01), Hafner et al.
patent: 5016819 (1991-05-01), Wood
patent: 5207384 (1993-05-01), Horsting
patent: 5236173 (1993-08-01), Wakeman
patent: 5255855 (1993-10-01), Maier et al.
patent: 5875972 (1999-03-01), Ren et al.
patent: 5887798 (1999-03-01), Ohta et al.
patent: 5921473 (1999-07-01), Romann
Siemens Automotive Corporation
Weldon Kevin
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