Fluid sprinkling – spraying – and diffusing – Including valve means in flow line – Reciprocating
Reexamination Certificate
1999-03-18
2001-08-28
Morris, Lesley D. (Department: 3752)
Fluid sprinkling, spraying, and diffusing
Including valve means in flow line
Reciprocating
C239S585100
Reexamination Certificate
active
06279844
ABSTRACT:
FIELD OF INVENTION
This invention relates to fuel injectors in general and particularly high-pressure direct injection fuel injectors. More particularly to high-pressure direct injection fuel injectors having a valve seat joined to a valve body.
BACKGROUND OF THE INVENTION
It is known in the art relating to fuel injectors to have a separate valve seat positioned proximate a valve body. In this type of injector arrangement, the valve seat and the valve body are arranged so that that the valve seat is located in a proper operative position in the fuel injector. The connection between the valve seat and valve body should fixedly secure the two components together, as well as, provide a hermetic seal that prevents fuel leaks.
It is believed that the connection between the valve seat and the valve body can be accomplished by different techniques. One known technique is a weld connection. In this arrangement, the valve seat is welded to an end of the valve body in such a fashion that the weld secures the valve seat within an end of the valve body and forms a hermetic seal between the valve seat and the valve body. Another known technique is the crimp/elastomer connection. In this arrangement, the end of the valve body is crimped around the valve seat to secure the valve seat within an end of the valve body. To ensure that a hermetic seal is achieved when the crimp arrangement is employed, an elastomeric member, such as an O-ring, is installed between the valve seat and the valve body.
In a direct injection application, the injector is required to operate in an environment of higher pressures and temperatures than a non-direct injection installation, such as, manifold injector installations. It is believed that the known connection techniques may not endure direct injection operative conditions over prolonged periods of time. The weld connection between the valve seat and the valve body does not provide a failsafe valve seat and valve body connection in the event of weld failure during prolonged operation. Catastrophic failure of the engine could result when the weld connection fails and valve seat enters the engine cylinder. It is also believed that the elastomer in the crimp/elastomer connection between the valve seat and the valve body will deteriorate during prolonged use in a direct injection application.
SUMMARY OF THE INVENTION
The present invention provides a fuel injector with a valve body having an inlet, an outlet, and an axially extending fuel passageway from the inlet to the outlet. An armature is located proximate the inlet of the valve body. A needle valve is operatively connected to the armature. A valve seat is located proximate the outlet of the valve body. A fault tolerant structural connection is provided between the valve seat and the valve body that also provides a hermetic seal between the valve seat and the valve body.
The fault tolerant structural connection is a mechanical connection between the valve seat and the valve body that ensures retention of the valve seat to the valve body and provides a hermetic seal between the valve seat and valve body. In a preferred embodiment of the invention, the fault tolerant structural connection comprises a crimped end section of the valve body that engages the valve seat and a weld joint between the valve body and valve seat. The weld joint, preferably, is a laser weld joint.
It is to be understood that the fault tolerant structural connection may comprise various arrangements. For example, the fault tolerant structural connection maybe a self-locking threads on the valve seat and the valve body and a weld joint between the valve body and the valve seat. Rather than self-locking threads, a slot and groove configuration on the valve seat and the valve body could be employed. Alternatively, the fault tolerant structural connection could comprise a self-locking threaded connection between the valve seat and valve body that forms a hermetic seal and a crimped end section of the valve body that engages the valve seat. In any event, each of the fault tolerant structural connections must be a mechanical connection between the valve seat and valve body that ensures retention of the valve seat to the valve body and provides a hermetic seal between the valve seat and the valve body.
The fuel injector of the present invention may also include a swirl generator that allows the fuel to form a swirl pattern on the valve seat in the fuel injector. The swirl generator, preferably, includes two flat disks. One disk is a guide disk having a perimeter, a central aperture, and at least one fuel passage opening between the perimeter and the central aperture. The other disk is a swirl disk having at least one slot extending tangentially from the opening to the central aperture of the guide disk. The valve seat includes a fuel passageway having a conical annulus extending between an upstream side of the valve seat and a downstream side of the valve seat. The needle valve includes a curved surface that mates with the conical annulus to inhibit fuel flow through the fuel passageway of the valve seat. The curved surface on the needle valve, preferably, is spherical.
The present invention also includes a method of securing a valve seat to a valve body in a fuel injector. The valve seat is secured to the valve body of the fuel injector by locating a valve seat within the end of a valve body; crimping an end section of the valve body to the valve seat; and welding the crimped end section of the valve body to the valve seat.
The method of the present invention also includes providing both the valve seat and the valve body with chamfers so that when the end section of the valve body is crimped to the valve seat a gap is formed with a distance that allows for a hermetic weld joint to be formed between the valve seat and the crimped end section of the valve body.
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Huszar Gyula A.
Shen Jingming J.
Morris Lesley D.
Siemens Automotive Corporation
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