Fuel injector with weld integrity arrangement

Fluid sprinkling – spraying – and diffusing – Processes – Of fuel injection

Reexamination Certificate

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Details

C239S585400, C239S585100, C285S288500, C029S890143

Reexamination Certificate

active

06283384

ABSTRACT:

BACKGROUND OF THE INVENTION
The present invention relates to a fuel injector assembly, and more particularly to a fuel injector assembly with a shell configured to allow fluid communication between an exterior surface of a body and a fuel passageway for particular weld integrities.
In a known system, the assembly of a fuel injector involves the insertion of a body into a shell. The body has an outside diameter which is slightly larger than the inside diameter of the shell. By this arrangement, an interference fit between the body and the shell is achieved. A lubricant is introduced on either or both of an exterior surface of the body and an interior surface of the shell to ease the insertion of the body into the shell. The body is hermetically attached to the interior surface of the shell by a weld. It is believed that both the use of a lubricant on and the use of an interference fit between the body and the shell lead to a few disadvantages. For example, during the forming of the weld, air and lubricant trapped between the body and the shell may become heated and expand in volume. The use of an interference fit between the body and the shell hinders the escape of the expanded air and lubricant. The integrity of the weld may be compromised, as the heated air and lubricant may expand through the weld. For these reasons, the use of an interference fit between a body and a shell of a fuel injector assembly necessitates a visual inspection of the weld.
It is further believed that due to the use of an interference fit between the body and the shell, pressure measurements upstream and downstream from the weld may not indicate whether the weld forms a hermetic seal. A satisfactory test result may only indicate that the interference fit between the body and the shell prevents the escape of a fluid.
SUMMARY OF THE INVENTION
The present invention provides a fuel injector having a fuel inlet, a fuel outlet, and a fuel passageway extending from the fuel inlet to the fuel outlet along a longitudinal axis. The fuel injector includes a body, an armature, a needle, and a shell. The body includes an inlet portion, an outlet portion, a body passage extending from the inlet portion to the outlet portion along the longitudinal axis, and an exterior surface. The armature is located adjacent the inlet portion of the body. The needle is operatively connected to the armature, the needle being positionable by the armature to permit or prohibit fuel flow through the fuel outlet. The shell includes a first end, a second end, and an interior surface disposed between the first end and the second end, the second end being welded to the exterior surface of the body, the interior surface cincturing the exterior surface of the body such that fluid communicates between the exterior surface of the body and the fuel passageway for particular weld integrities. Preferably, the interior surface of the shell includes a cut-out through which fluid communicates between the exterior surface of the body and the fuel passageway, a contact surface and a non-contact surface, the contact surface defining an area of contact between the interior surface of the shell and the exterior surface of the body, the non-contact surface being adjacent the fuel inlet of the fuel passageway, the cut-out extending a non-zero length of the non-contact surface and substantially an entire length of the contact surface. Preferably, the particular weld integrities are a fillet weld with a hermetic seal.
The present invention also provides a shell for a fuel injector having a fuel inlet, a fuel outlet, a fuel passageway extending from the fuel inlet to the fuel outlet, and a body with an exterior surface. The shell includes a first end, a second end, and an interior surface disposed between the first end and the second end. The interior surface includes a cut-out. Preferably, the interior surface of the shell is configured to cincture the exterior surface of the body such that fluid communicates between the exterior surface of the body and the fuel passageway for particular weld integrities. Preferably, the particular weld integrities are a fillet weld with a hermetic seal.
The present invention also provides a method of forming a fuel injector that allows weld integrity evaluation between a shell and a body of the fuel injector, the fuel injector having a fuel inlet, a fuel outlet, a fuel passageway extending from the fuel inlet to the fuel outlet along a longitudinal axis, the body having an exterior surface, and the shell having an interior surface. The method includes the steps of securing the shell to the exterior surface of the body, and cincturing the exterior surface of the body with the interior surface of the shell such that fluid communicates between the exterior surface of the body and the fuel passageway for particular weld integrities. Preferably, the interior surface of the shell includes a cut-out through which fluid communicates between the exterior surface of the body and the fuel passageway. Preferably, the particular weld integrities are a fillet weld with a hermetic seal.


REFERENCES:
patent: 2073093 (1937-03-01), Brantly
patent: 4946132 (1990-08-01), Reiter
patent: 5018555 (1991-05-01), Hawerkamp
patent: 5301874 (1994-04-01), Vogt et al.
patent: 5395050 (1995-03-01), Nowak et al.
patent: 5775600 (1998-07-01), Wildeson et al.
patent: 5826804 (1998-10-01), Reiter et al.

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