Information
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Patent Grant
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6334576
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Patent Number
6,334,576
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Date Filed
Friday, June 30, 200024 years ago
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Date Issued
Tuesday, January 1, 200222 years ago
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Inventors
-
Original Assignees
-
Examiners
-
CPC
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US Classifications
Field of Search
US
- 239 5851
- 239 5854
- 239 5855
- 239 584
- 239 53312
- 239 900
- 239 600
- 239 5
- 029 890142
- 029 890143
- 029 88844
- 029 88845
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International Classifications
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Abstract
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 an armature disposed within the body, a cylindrical needle operatively connected to the armature, the needle having a support portion and a flow control portion, and a seat disposed at the fuel outlet. The fuel injector also includes a ball operatively connected to the support portion of the needle such that the flow control portion protrudes from the ball toward the seat.
Description
FIELD OF INVENTION
This invention relates to fuel injectors in general, and more particularly to a fuel injector assembly which includes a modified needle tip having a ball seat with multiple tip geometry for fuel mixing for maximizing fuel combustion.
BACKGROUND OF THE INVENTION
In the case of internal combustion engines having fuel injection systems, fuel injectors are conventionally used to provide a precise amount of fuel needed for combustion. The fuel injector is required to deliver the precise amount of fuel per injection pulse and maintain this accuracy over the life of the injector. In order to optimize the combustion of fuel, certain strategies are required in the design of fuel injectors. These strategies are keyed to the delivery of fuel into the intake manifold of the internal combustion engine in precise amounts and flow patterns. Conventional fuel injector designs have failed to optimize the combustion of fuel injected into the intake manifold of an internal combustion engine.
SUMMARY OF THE INVENTION
The present invention overcomes the disadvantages of conventional fuel injectors and provides a fuel injector which incorporates a needle with a novel ball seat design and multiple tip geometries, which can provide various flow patterns and improved spray atomization for fuel for improved combustion.
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, a cylindrical needle slidingly disposed within the body, the needle having a support portion and a flow control portion, and a seat disposed at the fuel outlet. The fuel injector also includes a ball operatively connected to the support portion of the needle such that the flow control portion protrudes from the ball toward the seat.
The present invention also provides a method of controlling a fuel spray pattern in a fuel injector, the fuel injector having a body, a cylindrical needle slidingly disposed within the body, the needle having a support portion and a flow control portion, and a seat disposed at the fuel outlet. The method includes the steps of providing a ball operatively connected to the support portion of the needle such that the flow control portion protrudes from the ball toward the seat and providing fuel to the fuel injector.
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.
FIG. 1
is a cross-sectional view of a fuel injector of the present invention taken along its longitudinal axis;
FIG. 2
is a plan view of the ball seat of the present invention of
FIG. 1
;
FIG. 3A
is a plan view of a needle tip with a concave tip geometry; and
FIG. 3B
is a plan view of a needle tip with a linear tip geometry.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
FIG. 1
illustrates a fuel injector assembly
10
, such as a fuel injector assembly
10
. 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
18
. 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
is provided in the inlet passage
26
. The adjustable tube
30
is positionable along the longitudinal axis
18
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 armature, control the quantity of fuel flow through the fuel injector assembly
10
. 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 ECU (not shown). An elastomeric O-ring
34
is provided in a groove on an exterior extension of the inlet member
24
. The O-ring
34
is biased by a flat spring
38
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 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 the socket
20
a
of the overmolded plastic member
20
. An armature
46
is supported for relative movement along the axis
18
with respect to the inlet member
24
. The armature
46
is supported by a spacer
48
, a body shell
50
, and a body
52
. The armature
46
has an armature passage
54
in fluid communication with the inlet passage
26
.
The spacer
48
engages the body shell
50
, which 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
. The armature passage
54
of the armature
46
is in fluid communication with the body passage
58
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 needle
68
. The needle
68
is operatively connected to the armature
46
, and can be a substantially cylindrical needle
68
. The cylindrical needle
68
is centrally located within and spaced from the neck portion so as to define a part of the body passage
58
. The cylindrical needle
68
is axially aligned with the longitudinal axis
18
of the fuel injector assembly
10
. A ball
81
is operatively connected to the cylindrical needle
68
proximate the fuel injector outlet
14
at needle support portion
90
. A needle control portion (tip)
79
protrudes out of a through passage
81
′ (hidden) in the ball
81
.
Operative performance of the fuel injector assembly
10
is achieved by magnetically coupling the armature
46
to the end of the inlet member
26
that is closest to the inlet portion
60
of the body
52
. Thus, the lower portion of the inlet member
26
that is proximate to the armature
46
serves as part of the magnetic circuit formed with the armature
46
and coil assembly
40
. The armature
46
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 armature
46
along the longitudinal axis
18
of the fuel injector assembly
10
. The electromagnetic force is generated by current flow from the ECU (not shown) through the coil assembly
40
. Movement of the armature
46
also moves the operatively attached needle
68
. As shown in
FIGS. 1-3B
, ball
81
is operatively connected to needle
68
and engages the seat
64
. Ball
81
opens and closes the seat passage
76
of the seat
64
of the present invention to permit or inhibit, respectively, fuel from exiting the outlet of the fuel injector assembly
10
. In order to open seat passage
76
, the seal between the ball
81
and the seat
64
is broken by upward movement of the needle
68
. The needle
68
moves upwards when the magnetic force is substantially higher then it needs to be to lift the armature needle assembly against the force of spring
32
. In order to close the seat passage
76
of the seat
64
, the magnetic coil assembly
40
is de-energized. This allows ball
81
to re-engage surface
80
of seat
64
and close passage
76
. The surface
78
of ball
81
is preferably a spherical surface. During operation, fuel flows in fluid communication from the fuel inlet source (not shown) through the fuel inlet passage
26
of the inlet member
24
, the armature passage
54
of the armature
46
, the body passage
58
of the body
52
, and the seat passage
76
of the seat
64
and is injected from the outlet
14
of the fuel injector assembly
10
.
The ball
81
and the needle flow control portion
79
will now be described in detail. As shown in
FIGS. 3A and 3B
, the ball
81
is attached to the needle
68
by means of welding, press fitting, or by any other means well known in the art. Because mating between the surface
78
of ball
81
and the surface
80
of seat
64
is the only means of preventing fuel from ejecting through the passage
76
of seat
64
, a highly accurate surface finish for the ball surface
78
is required. The needle flow control portion
79
however only affects the spray pattern and the particle sizes emitted from the passage
76
of seat
64
. Thus a highly accurate surface finish for needle flow control portion
79
is not required. The present invention therefore provides a ball
81
which has a highly accurate machined surface
78
that mates with the highly accurate surface
80
of seat
64
. Before or after welding or press fitting of ball
81
onto needle
68
, the exposed needle flow control portion
79
can be machined as necessary.
FIG. 3A
shows a machined needle flow control portion
79
that has concave sides
79
′. Similarly,
FIG. 3B
shows a machined needle flow control portion
79
that has linear sides
79
″. It can be appreciated that as the fuel passes through body passage
58
towards seat passage
76
, the concave sides
79
′ of needle flow control portion
79
will disperse the fuel in a wider pattern than that for the linear sides
79
″ of needle flow control portion
79
. Similarly, one of ordinary skill in the art could envision a variety of other flow control portion configurations (i.e. convex, notched, sloped and varying cross-sections relative to the needle longitudinal axis) that would yet further improve or alter spray atomization and the spray pattern, and reduce the sac volume in the area between the ball and seat sealing surfaces and the seat passage
76
, for fuel injectors and other such devices.
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 sphere 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 fall scope defined by the language of the following claims, and equivalents thereof.
Claims
- 1. 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 comprising:a body; a cylindrical needle slidingly disposed within the body, the needle having a support portion and a flow control portion; a seat disposed at the fuel outlet; and control portion protrudes from tha ball toward the seat.
- 2. The fuel injector of claim 1, wherein the flow control portion protrudes out of a through passage in the ball and is configured to control the fuel spray pattern.
- 3. The fuel injector of claim 1, wherein the flow control portion has a similar cross-section as the needle transverse to a needle longitudinal axis.
- 4. The fuel injector of claim 1, wherein the flow control portion has a different cross-section than the needle transverse to a needle longitudinal axis.
- 5. The fuel injector of claim 1, wherein the flow control portion is machined separately from the ball.
- 6. The fuel injector of claim 1, wherein the flow control portion has a concave cross-section in a needle longitudinal axis direction.
- 7. The fuel injector of claim 1, wherein the flow control portion has a convex cross-section in a needle longitudinal axis direction.
- 8. The fuel injector of claim 1, wherein the flow control portion has a sloped cross-section in a needle longitudinal axis direction.
- 9. The fuel injector of claim 1, wherein the flow control portion has a notched cross-section in a needle longitudinal axis direction.
- 10. A method of controlling a fuel spray pattern in a fuel injector, the fuel injector having a body, a cylindrical needle slidingly disposed within the body, the needle having a support portion and a flow control portion, and a seat disposed at the fuel outlet, and method comprising the steps of:providing a ball operatively connected to the support portion of the needle such that the flow control portion of the needle protrudes from the ball toward the seat; and providing fuel to the fuel injector.
- 11. The method according to claim 10, wherein the flow control portion protrudes out of a through passage in the ball and is configured to control the fuel spray pattern.
- 12. The method according to claim 10, wherein the flow control portion has a similar cross-section as the needle transverse to a needle longitudinal axis.
- 13. The method according to claim 10, wherein the flow control portion has a different cross-section than the needle transverse to a needle longitudinal axis.
- 14. The method according to claim 10, wherein the flow control portion is machined separately from the ball.
- 15. The method according to claim 10, wherein the flow control portion has a concave cross-section in a needle longitudinal axis direction.
- 16. The method according to claim 10, wherein the flow control portion has a convex cross-section in a needle longitudinal axis direction.
- 17. The method according to claim 10, wherein the flow control portion has a sloped cross-section in a needle longitudinal axis direction.
- 18. The method according to claim 10, wherein the flow control portion has a notched cross-section in a needle longitudinal axis direction.a ball operatively connected to the support portion of the needle such that the flow control portion of the needle protrudes from the ball toward the seat.
US Referenced Citations (9)