Engine fuel injector

Details Engine fuel injector Engine fuel injector

1999-05-26

2001-07-24

Douglas, Lisa Ann (Department: 3752)

Fluid sprinkling, spraying, and diffusing

Processes

Of fuel injection

C239S585100

Reexamination Certificate

active

06264112

ABSTRACT:

TECHNICAL FIELD
This invention relates to engine fuel injectors. A particular embodiment involves a solenoid actuated fuel injector including an endoskeletal continuous tube within which fuel flow is contained and which supports the various components making up the injector.
BACKGROUND OF THE INVENTION
It is well known in the automotive engine art to provide solenoid actuated fuel injectors for controlling the injection of fuel into the cylinders of spark ignition engines, generally through intake manifold runners or intake ports of the cylinders. Generally, such injectors include a body having added internal and external components which are assembled and welded, brazed or otherwise sealed together to provide internal fuel passages for conducting fuel flow. In some designs, the actuating solenoid coil is exposed to fuel passing through the injector. Such injectors may also involve assembly of many small components housed within a body having an internal coil joined with a connector and enclosed by an overmolded protective material.
It is desirable to provide an injector having reduced complexity and assembly costs as well as improved protection against fuel leakage and coil failures.
SUMMARY OF THE INVENTION
The present invention provides a novel injector having a number of improved features combined in a preferred embodiment. Some of the features are optionally combinable with other forms of injectors and components to provide various combinations of components and features.
A primary feature of the invention is that it includes a continuous endoskeletal tube enclosing a continuous passage for fuel flow through the injector from an inlet end to an outlet end of the tube. In general, the tube provides a skeleton or support within or on which all the other components of the injector are mounted.
A valve seat is fixed at the outlet end of the tube which may have a straight or expanded outlet end for supporting the valve seat.
An injection valve is slidable within the tube and is biased against the valve seat to close off fuel flow therethrough. The valve has an armature which is attracted to a tubular pole mounted within the tube by energizing of a coil surrounding the tube. Optionally, the tubular pole may be adjusted during assembly to establish the operating stroke of the valve prior to fixing the tubular pole in the adjusted position.
The electrical coil may be formed as a coil assembly including an attached connector with enclosed terminals. The complete coil assembly has a central opening through the coil that allows the coil assembly to be slipped over the tube during assembly of the injector. The continuous tube prevents fuel in the internal passage from contacting the coil and other elements that are mounted on the exterior of the tube.
A magnetic body or strap at least partially surrounds the coil and has upper and lower ends connected with the exterior of the tube to form a magnetic flux concentrating path through the body, coil and armature so as to attract the armature to the pole when the coil is energized.
A separate tubular or hollow component or support element may be provided which is assembled over the tube to engage and possibly surround the coil body. The support element may include a clip groove for connecting the support element and the injector to an associated fuel rail by means of a retaining clip or other suitable retaining means. The support element may also provide a backup surface for an inlet end seal ring which may be retained in place by a push-on rail seal retainer forced over the inlet end of the injector tube and retained by friction or other suitable means.
Various embodiments of valve seats and/or associated components are possible.
In one embodiment having a straight line tube, a valve seat is secured to the outlet end of the tube and includes an integral multi-hole director for directing fuel spray from one or more openings in the valve seat which are controlled by the associated valve.
In other embodiments, the outlet end of the tube is expanded to form a short cylindrical portion in which a valve seat is received and retained by crimping over the outlet end of the tube. A lower guide disc may be seated in the cylindrical portion between the valve seat and a flange formed by the outwardly expanded portion of the tube. A discharge opening in the valve seat may connect with a circular recess in which a director having multiple spray directing holes is retained. The director may be a disc element retained by a press fitted cup-shaped member. Alternatively, the director may be formed as a cup-shaped member retained by press fitting. Either of these versions could be supplementally retained by tack welding or other means for positively holding the retainer in place.
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: 4274598 (1981-06-01), Wilfert et al.
patent: 4742964 (1988-05-01), Ito et al.
patent: 5694898 (1997-12-01), Pontoppidan et al.
patent: 5803052 (1998-09-01), Lorraine et al.
patent: 5875972 (1999-03-01), Ren et al.
patent: 5915626 (1999-06-01), Awarzamani et al.

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