Information
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Patent Grant
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6676046
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Patent Number
6,676,046
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Date Filed
Monday, August 6, 200123 years ago
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Date Issued
Tuesday, January 13, 200420 years ago
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Inventors
-
Original Assignees
-
Examiners
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CPC
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US Classifications
Field of Search
US
- 239 5851
- 239 5852
- 239 5854
- 239 5855
- 239 900
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International Classifications
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Abstract
A fuel injector having a housing including an inlet, an outlet, and a passageway for fuel flow from the inlet to the outlet. A coil assembly is disposed proximate the inlet of the fuel injector. A seat is disposed proximate the outlet of the fuel injector. A closure member is disposed in the housing and operable by the coil assembly to permit and prohibit fuel flow through the seat. The closure member includes a strap member that extends along a longitudinal axis and has at least two radial projections and a central member. The strap member includes an outer surface a distance D from the longitudinal axis. The at least two radial projections having first and second ends. A sealing member is coupled to the central member. An armature member is coupled to the second ends of the strap member. Also, a method for forming the strap member.
Description
FIELD OF INVENTION
The invention relates to a closure member for a fuel injector, and more particularly to a closure member construction that may be varied to provide length compensation.
BACKGROUND OF THE INVENTION
It is known to use a variety of closure mechanisms to permit and inhibit fuel flow through fuel injectors. These mechanisms include needle and armature, ball and armature combinations. It is believed that the method of fabrication to create such components should be low cost, repeatable and accurate. It is believed to be known that previous designs of closure mechanisms either used the armature itself as the length compensator, the needle as the length compensator and or incorporated a more expensive manufacturing method for the compensator component. These designs are believed to suffer from disadvantages including additional manufacturing steps and increased costs.
SUMMARY OF THE INVENTION
The present invention provides a fuel injector having a housing including an including an inlet, an outlet, and a passageway for fuel flow from the inlet to the outlet. A coil assembly is disposed proximate the inlet of the fuel injector. A seat is disposed proximate the outlet of the fuel injector. A closure member is disposed in the housing and operable by the coil assembly to permit and prohibit fuel flow through the seat. The closure member includes a strap member that extends along a longitudinal axis. The strap member has at least two radial projections and a central member. The strap member includes an outer surface a distance D from the longitudinal axis. The at least two radial projections having first and second ends. The closure member further includes a sealing member coupled to the central member and an armature member coupled to the second ends of the strap member.
The present invention further provides a method of forming a strap member that is disposed in an closure member of a fuel injector. The method can be achieved by stamping a planar component that has at least one central member and at least two radial projections disposed about a longitudinal axis and forming the at least two radial projections along the longitudinal axis.
BRIEF DESCRIPTION OF THE DRAWINGS
The accompanying drawings, which are incorporated herein and constitute part of this specification, illustrate presently preferred embodiments of the invention, and, together with the general description given above and the detailed description given below, serve to explain features of the invention. In the Figures:
FIG. 1
shows a cross-sectional view of a fuel injector assembly including the closure member.
FIG. 2
shows a perspective view of the closure member.
FIG. 3
shows a plan view of the planar strap member.
FIG. 4
shows a perspective view of the formed strap member.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT(S)
FIG. 1
shows an example of a fuel injector
10
including a closure member
70
. The fuel injector assembly
10
has a housing, which includes a fuel inlet
12
, a fuel outlet
14
, and a fuel passageway
16
extending from the fuel inlet
12
to the fuel outlet
14
along a longitudinal axis A. The housing includes an overmolded plastic member
20
cincturing a metallic support member
22
. A fuel inlet member
24
with an inlet passage
26
is disposed within the overmolded plastic member
20
. The inlet passage
26
serves as part of the fuel passageway
16
of the fuel injector assembly
10
. A fuel filter
28
and an adjustable tube
30
are provided in the inlet passage
26
. The adjustable tube
30
is positionable along the longitudinal axis A before being secured in place, thereby varying the length of an armature bias spring
32
. In combination with other factors, the length of the spring
32
, and hence the bias force against the closure member
70
, controls the quantity of fuel flow through the injector.
The overmolded plastic member
20
also supports a socket
20
a
that receives a plug (not shown) to operatively connect the fuel injector assembly
10
to an external source of electrical potential, such as an electronic control unit (not shown). An elastomeric O-ring
34
is provided in a groove on an exterior of the inlet member
24
to sealingly secure the inlet member
24
to a fuel supply member (not shown), such as a fuel rail.
The metallic support member
22
encloses an electromagnetic actuator assembly. An example of the actuator is a coil assembly
40
. The coil assembly
40
includes a bobbin
42
that retains a coil
44
. The ends of the coil assembly
40
are electrically connected to pins
40
a
mounted within the socket
20
a
of the overmolded plastic member
20
. The closure member
70
is supported for relative movement along the longitudinal axis A with respect to the inlet member
24
. The closure member
70
is supported by a body shell
50
and a body
52
.
The body shell
50
engages the body
52
. An armature guide eyelet
56
is located on an inlet portion
60
of the body
52
. An axially extending body passage
58
connects the inlet portion
60
of the body
52
with an outlet portion
62
of the body
52
. A seat
64
, which is preferably a metallic material, is mounted at the outlet portion
62
of the body
52
.
The body
52
includes a neck portion
66
that extends between the inlet portion
60
and the outlet portion
62
. The neck portion
66
can be an annulus that surrounds a portion of the closure member
70
.
Operative performance of the fuel injector assembly
10
is achieved by magnetically coupling the closure member
70
to the end of the inlet member
24
that is closest to the inlet portion
60
of the body
52
. Thus, the lower portion of the inlet member
24
that is proximate to the closure member
70
serves as part of the magnetic circuit formed with the coil assembly
40
. The closure member
70
is guided by the armature guide eyelet
56
and is responsive to an electromagnetic force generated by the coil assembly
40
for axially reciprocating the closure member
70
along the longitudinal axis A of the fuel injector assembly
10
. The electromagnetic force is generated by current flow from the electronic control unit (not shown) through the coil assembly
40
. Movement of the closure member
70
opens and closes a seat passage
68
of the seat
64
, which permits or inhibits, respectively, fuel from flowing through the fuel outlet
14
of the fuel injector
10
.
Fuel that is to be injected from the fuel injector
10
is communicated from the fuel inlet source (not shown), to the fuel inlet
12
, through the fuel passageway
16
, and exits from the fuel outlet
14
. The fuel passageway
16
includes the inlet passage
26
of the inlet member
24
, the body passage
58
of the body
52
, and the seat passage
68
of the seat
64
.
The closure member
70
will now be discussed in greater detail. The closure member
70
is disposed in the fuel injector housing and is operable by the coil assembly
40
to permit and prohibit fuel flow through the seat passage
68
of the seat
64
. There is shown in
FIG. 2
a perspective view of the closure member
70
. The closure member
70
has a non-magnetic strap member
15
, an armature member
37
and a sealing component
36
.
There is shown in
FIG. 3
a planar strap member
15
. The planar strap member
15
has at least one central member
19
and at least two radial projections
17
. The central member
19
and the at least two radial projections
17
are disposed about the longitudinal axis A. The central member
19
has a perimeter
32
and at least two connecting tabs
38
. The perimeter
32
may provide a first perimeter
32
a
, a second perimeter
32
b
, a third perimeter
32
c
and a fourth perimeter
32
d
. The at least two connecting tabs
38
are engaged to the central member
19
via the first perimeter
32
a
and the second perimeter
32
b
. The at least two radial projections
17
are engaged to the central member
19
via the third perimeter
32
c
and fourth perimeter
32
d
. The at least two radial projections
17
are formed normal to the longitudinal axis A and circumferentially about the third perimeter
32
c
and fourth perimeter
32
d
. The at least two connecting tabs
38
are formed normal to the longitudinal axis A and circumferentially about the first perimeter
32
a
and second perimeter
32
b
. Forming the at least two radial projections
17
and the at least two connecting tabs
38
normal to the longitudinal axis A and circumferentially about their respective perimeters results in a tubularly formed strap member
31
.
FIG. 4
shows the detail of the formed strap member
31
. The at least one central member
19
preferably has a center hole
25
. The center hole
25
is preferably pierced at the same time the planar strap member
15
is stamped. The sealing component
36
is coupled to the center hole
25
of the at least one central member
19
. The sealing component
36
and the at least one central member
19
are coupled by a weld
25
. It should be recognized by those skilled in the art that other methods for coupling the sealing component
36
and the at least one central member
19
are available. Examples of such other methods of assembly include puddle brazing, the use of adhesives and friction fitting so long as the sealing component
36
and the at least one central member
19
are secured together for relative movement. In a preferred embodiment, the sealing component
36
is a ball bearing. Those skilled in the art will recognize that other configurations and types of sealing components may be employed.
As shown in
FIG. 2
the armature member
37
may be coupled by welds
21
to second ends
48
of the at least two radial projections
17
. Openings
29
are provided between the at least two radial projections
17
after they have been formed. Automotive fuel is free to flow through the armature member
37
and out the openings
29
that are created when the at least two radial projections
17
are formed. The openings
29
along the length of the radial projections
17
provide an excellent area for full vapor purging during hot fuel handling operation. The geometries of the openings
29
are rectangular (non-circular) as well, which also improves the vapor handling, as vapor bubbles are typically spherical.
The strap member
15
is preferably made from a non-magnetic material. This allows for magnetic de-coupling between the armature member
37
and the sealing component
36
. A length is associated with the distance between first ends
46
and the second ends
48
of the at least two radially formed projections
17
along the longitudinal axis A. The length may be varied in order to fabricate strap members
15
of different length. For example, if a closure member
70
with an extended tip is required for a particular fuel injector application, then the length of the strap member
15
may be increased. Thus, once assembled, the overall length of the closure member
70
is now increased.
There is an impact load on the strap member
15
of the closure member
70
that is generated by the reciprocation of the closure member
70
in the fuel injector
10
. The impact load may act to deform the strap member
15
over the life of the fuel injector
10
. In order to assure that there is virtually no deformation in the strap member
15
the following criteria must be observed. The cross sectional area of the strap member
15
in square inches, multiplied by the material yield strength of the strap member
15
in PSI, must be sufficient such that the strap member
15
will not plastically deform and possibly shorten, due to the repeated impacts generated by the load. If the closure member
70
were to shorten, it could change the performance of the fuel injector
10
.
A method of forming a strap member disposed in a closure member of a fuel injector will now be described. The method may be achieved by stamping the planar strap member
15
having the at least one central member
19
and at least two radial projections
17
disposed about a longitudinal axis A. The at least two radial projections
17
are then formed normal to the longitudinal axis A. In the embodiment shown in
FIG. 3
, the planar strap member
15
is stamped and then formed as a second operation. Those skilled in the art will recognize that other low cost, accurate, and repeatable processes for creating the planar strap member
15
are available. They include drawn and EDM processes.
In an alternate embodiment, the planar strap member
15
may be stamped such that when formed, the strap member
31
is shaped like a rectangular box. In this embodiment, the at least one central member
19
may provide two central members
19
and the at least two radial projections may provide four radial projections
17
. The sealing component
36
is coupled to the first one of the at least two central members
19
and the armature member
37
is coupled to the second one of the at least two central members
19
. The four radial projections
17
are formed perpendicular to the longitudinal axis A.
In other embodiments, the planar strap member
15
may be stamped such that multiple combinations of radial projections
17
may be formed. For example, a strap member
31
with three radial projections
17
may be formed. In another example, a strap member
31
with six radial projections
17
may be formed.
While the present invention has been disclosed with reference to certain preferred embodiments, numerous modifications, alterations, and changes to the described embodiments are possible without departing from the spirit and scope of the present invention, as defined in the appended claims. Accordingly, it is intended that the present invention not be limited to the described embodiments, but that it have the full scope defined by the language of the following claims, and equivalents thereof.
Claims
- 1. A fuel injector having a housing including an inlet, an outlet, and a passageway for fuel flow from the inlet to the outlet, the fuel injector comprising:a coil assembly disposed proximate the inlet of the fuel injector; a seat disposed proximate the outlet of the fuel injector; and a closure member disposed in the housing and operable by the coil assembly to permit and prohibit fuel flow through the seat, the closure member including; a unitary strap member extending along a longitudinal axis and having at least two projections and a central member defining an annulus having a concave surface facing the inlet about the longitudinal axis, the at least two projections having a first end extending from the concave surface of the annulus toward a second ends along the longitudinal axis, the at least two projections defining a first perimeter at the largest cross-sectional area of the projections about the longitudinal axis, the at least two projections being spaced apart about the longitudinal axis by openings extending along the length of each of the projections between the first end and second end; a sealing member coupled to the central member, the sealing member having a portion surrounded by the concave surface of the annulus, the sealing member defining a second outermost perimeter at the largest cross-sectional area about the longitudinal axis being less than the first perimeter; and an armature member coupled to the second ends of the strap member.
- 2. The fuel injector according to claim 1, wherein each of the strap member and the armature member includes at least one flow hole therethrough, the at least one flow holes defining a fuel passage from the inlet to the outlet of the fuel injector.
- 3. The fuel injector according to claim 2 further comprising at least one flow holes disposed between the at least two projections of the strap member.
- 4. The fuel injector according to claim 1 wherein the at least one central member comprises a center hole formed on the central member and located generally about the longitudinal axis.
- 5. The fuel injector according to claim 1, wherein the sealing member comprises a spherical shaped member to engage the seat.
- 6. The fuel injector according to claim 5, wherein the spherical shaped member comprises a ball.
- 7. The fuel injector according to claim 1 wherein the strap member is fabricated out of a non-magnetic material.
- 8. The fuel injector according to claim 1 wherein a length is associated with the distance between the first end and the second end along the longitudinal axis.
- 9. The fuel injector according to claim 8 wherein the length may be varied.
- 10. The fuel injector according to claim 1 wherein the central member further comprises a perimeter and at least two connecting tabs.
- 11. The fuel injector according to claim 10 wherein the perimeter comprises a first, second, third and fourth perimeters.
- 12. The fuel injector according to claim 11 wherein the at least two connecting tabs are engaged to the first and second perimeters.
- 13. The fuel injector according to claim 12 wherein the at least two projections are engaged to the third and fourth perimeters.
- 14. The fuel injector according to claim 13 wherein the at least two projections are formed normal to the longitudinal axis and about at least two perimeters disposed on a common axis of the first, second, third and fourth perimeters.
- 15. The fuel injector of claim 1, wherein the central member comprises a convex surface facing the outlet, the concave and convex surfaces disposed orthogonally about the longitudinal axis.
- 16. The fuel injector of claim 15, wherein the sealing member includes a portion fixed to the convex surface by a weld between the annulus and the portion of the sealing member.
US Referenced Citations (7)