Fluid sprinkling – spraying – and diffusing – Including valve means in flow line – Reciprocating
Reexamination Certificate
1999-12-06
2001-02-13
Morris, Lesley D. (Department: 3752)
Fluid sprinkling, spraying, and diffusing
Including valve means in flow line
Reciprocating
Reexamination Certificate
active
06186421
ABSTRACT:
TECHNICAL FIELD
This invention relates to fuel injectors used for delivery of fuel to internal combustion engines.
BACKGROUND OF THE INVENTION
A solenoid actuated valve assembly operates to inject fuel into an internal combustion engine. To actuate the valve, a magnetic circuit must be established to attract the valve armature to lift the valve off the valve seat. There must be a closed loop of adjacent magnetic components encircling the coil, except for the small working air gap across which the valve assembly armature travels. To satisfy this requirement for a closed loop about the coil, the components may have to be configured in complex geometries which increase manufacturing costs.
For efficient and accurate operation of fuel injection, it is desired to center the valve assembly concentrically within the injector body to ensure axial motion of the valve with respect to the body and the valve seat. In order to achieve this goal, it is preferable for a valve guide to be in direct contact with both the valve and the inner surface of the injector body to ensure concentricity therebetween.
It is also important that the solenoid coil be free of fuel contamination to assure reliable performance. Over time, fuel may degrade the coil windings resulting in reduced injector performance. A known option is to employ hermetic welds between the components encircling the coil to prevent fuel seepage into the coil. The disadvantage of hermetic welds is the increase in assembly costs.
SUMMARY OF THE INVENTION
The present invention is directed to a fuel injector, for use in an internal combustion engine, which includes a novel magnetic circuit pole subassembly. The pole subassembly includes a fuel tube with a lower radial flange, a cylindrical valve guide with a complementary radial flange mating with and hermetically welded to the fuel tube flange to form a fuel-tight cylindrical wall, and a cylindrical pole piece closely encircled by the fuel-tight cylindrical wall.
The cylindrical valve guide and the fuel tube form the fuel-tight cylindrical wall to provide a barrier to fuel seepage into a solenoid actuator assembly. Only one hermetic weld is required between the fuel tube and valve guide mating flanges to achieve fuel containment and seal the solenoid assembly from the risk of fuel contamination. Minimizing the number of hermetic welds required reduces assembly costs for the fuel injector.
The fuel tube radial flange extends to meet the injector body thereby directly integrating the fuel tube into the loop of adjacent magnetic components encircling the solenoid coil which conduct the magnetic circuit upon energization of the solenoid. By integrating the fuel tube into the circuit, the pole piece is simplified to a constant diameter tubular configuration.
The valve guide radial flange extends to directly contact the inner surface of the injector body which provides a centered valve guide relative to the body. This ensures that the injector valve, guided through direct contact with the valve guide, is concentric with the body and translates parallel to the body axis thereby improving injector performance.
REFERENCES:
patent: 5769328 (1998-06-01), Zdyb et al.
patent: 5927613 (1999-07-01), Koyanagi et al.
patent: 5967424 (1999-10-01), Bonnah, II
patent: 5996911 (1999-12-01), Gesk et al.
patent: 6105884 (2000-08-01), Molnar et al.
patent: 6123275 (2000-09-01), Geiger et al.
Bonnah, II Harrie William
Kotkowicz George A.
Schneider Michael
Wahba Brent Jack
Delphi Technologies Inc.
Kim Christopher S.
Morris Lesley D.
VanOphem John A.
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