Information
-
Patent Grant
-
6279844
-
Patent Number
6,279,844
-
Date Filed
Thursday, March 18, 199925 years ago
-
Date Issued
Tuesday, August 28, 200123 years ago
-
Inventors
-
Original Assignees
-
Examiners
-
CPC
-
US Classifications
Field of Search
US
- 239 5854
- 239 5855
- 239 5853
- 239 5851
- 239 596
- 239 463
- 219 12163
- 219 12164
-
International Classifications
-
Abstract
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 proximate the inlet of the valve body. A needle valve operatively connected to the armature. A valve seat proximate the outlet of said valve body. A fault tolerant structural connection between the valve seat and valve body that also provides a hermetic seal between the valve seat and valve body.
Description
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.
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 a 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 taken along its longitudinal axis.
FIG. 2
is an enlarged cross sectional view of the valve seat portion of the fuel injector shown in FIG.
1
.
FIG. 3
is a cross-sectional side view of the fuel injector valve body prior to installation in the fuel injector illustrated in FIG.
1
.
FIGS. 4A and 4B
are plan views of components of the fuel injector's swirl generator illustrated in FIGS.
1
and
2
.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS(S)
FIG. 1
illustrates a preferred embodiment of the high-pressure direct injection fuel injector of the present invention. The fuel injector
10
has an overmolded plastic member
12
encircling a metallic housing member
14
. A fuel inlet
16
with an in-line fuel filter
18
and an adjustable fuel inlet tube
20
are disposed within the overmolded plastic member
12
and metallic housing member
14
. The adjustable fuel inlet tube
20
is longitudinally adjustable to vary the length of an armature bias spring
22
, which adjusts the fluid flow within the fuel injector
10
. The overmolded plastic member
12
also supports a connector
24
that connects the fuel injector
10
to an external source of electrical potential, such as an electronic control unit (ECU, not shown). An O-ring
26
is provided on the fuel inlet
16
for sealingly connecting the fuel inlet
16
with a fuel supply member, such as a fuel rail (not shown).
The metallic housing member
14
encloses a bobbin
28
and a solenoid coil
30
. The solenoid coil
30
is operatively connected to the connector
24
. The portion of the inlet tube
32
proximate the bobbin
28
and solenoid coil
30
functions as a stator. An armature
34
is axially aligned with the inlet tube
16
by a valve body shell
36
and a valve body
38
.
The valve body
38
is disposed within the valve body shell
36
. An armature guide eyelet
40
is located at the inlet of the valve body. An axially extending fuel passageway
42
connects the inlet
44
of the valve body with the outlet
46
of the valve body
38
. A valve seat
50
is located proximate the outlet
46
of the valve body. Fuel flows in fluid communication from the fuel inlet source (not shown) through the fuel inlet
16
, the armature fuel passage
52
, and valve body fuel passageway
42
, and exits the valve seat fuel passageway
54
.
The fuel passage
52
of the armature is axial aligned with the fuel passageway
42
of the valve body. Fuel exits the fuel passage
52
of the armature through a pair of transverse ports
56
and enters the inlet
44
of the valve body
38
. The armature
34
is magnetically coupled to the portion of the inlet tube
32
that serves as a stator. The armature
34
is guided by the armature guide eyelet
40
and axially reciprocates along the longitudinal axis
58
of the valve body in response to an electromagnetic force generated by the solenoid coil
30
. The electromagnetic force is generated by current flow from the ECU through the connector
24
to the ends of the solenoid coil
30
wound around the bobbin
28
. A needle valve
60
is operatively connected to the armature
34
and operates to open and close the fuel passageway
54
in the valve seat, which allows and prohibits fuel from exiting the fuel injector
10
.
The valve seat
50
is positioned proximate the outlet
46
of the valve body
38
. The fuel injector
10
of the present invention includes a fault tolerant structural connection
62
between the valve seat
50
and the valve body
38
that also provides a hermetic seal between the valve seat
50
and the valve body
38
.
FIG. 2
illustrates a preferred embodiment of the fault tolerant structural connection
62
invention of the present invention. The connection comprises a crimped end section
64
of the valve body
38
that engages the valve seat
50
and a weld joint
66
between the valve body
38
and the valve seat
50
.
The valve seat
50
and the valve body
38
are provided with specified chamfers so that the crimped end section
64
and the valve seat
50
retain a physical relationship that allows for the weld joint
66
to be formed. More particularly, the chamfer angles are selected so that when the end section of the valve body is crimped, the crimped section engages the valve seat with minimal spring back. That is, the elastic properties of the metallic material that comprises the end section of the valve body are minimized. Preferably, the metallic material of the crimped end section of the valve body plastically deforms to engage the valve seat.
As illustrated in
FIG. 2
, the preferred valve seat
50
has a chamfer of approximately 60° included angle, while the crimped end section
64
of the valve body
38
has approximately a 70° included angle. As illustrated in
FIG. 3
, the preferred pre-crimped end section
68
of the valve body has a chamfer of approximately 20° included angle.
The weld joint
66
, preferably, comprises a laser weld joint. The laser weld joint comprises a portion of the valve body and a portion of the valve seat. The portion of the valve body
38
is greater than the portion of the valve seat
50
. The portion of the valve body
38
comprises approximately ⅔ of the laser weld joint and the portion of the valve seat
50
comprises approximately ⅓ of the laser weld joint. The valve body
38
, preferably, comprises 416P70 stainless steel. The valve seat
50
, preferably, comprises 440C carbon steel.
In the preferred embodiment of the invention, a swirl generator
70
is located upstream of the valve seat
50
in the fuel passageway
42
of the valve body
38
, and allows fuel to form a swirl pattern on the valve seat
50
. The swirl generator
70
, preferably, is constructed from at least one flat disk; however, various configurations of a swirl generator could be employed. The swirl generator
70
, as illustrated in
FIG. 2
, includes a pair of flat disks, a guide disk
72
and a swirl disk
74
.
The guide disk
72
, illustrated in
FIG. 4A
, has a perimeter
76
, a central aperture
78
, and a plurality of fuel passage openings
80
between the perimeter
76
and the central aperture
78
. Alternatively, a single fuel passage opening could be employed. The swirl disk
74
, illustrated in
FIG. 4B
, has a plurality of slots
82
that corresponds to the plurality of fuel passage openings
80
in the guide disk
72
. Each of the slots
82
extends tangentially from the respective fuel passage opening
84
toward a central aperture region
86
, and provides a tangential fuel flow path for fuel flowing through the swirl disk
74
to a valve needle
60
.
The needle valve
60
is guided in the central aperture
78
of the guide disk
72
. The plurality of fuel passage openings
80
supply fuel from the fuel passageway
42
to the swirl disk
74
. The swirl disk
74
directs fuel from the fuel passage openings
80
in the guide disk
72
and meters the fuel flow to the valve seat
60
. The guide and swirl disks
72
,
74
that form the swirl generator
70
are connected, preferably, by a weld connection to the valve seat
50
.
The fuel passageway
54
of the valve seat
50
has a conical annulus
90
extending between an upstream side of the valve seat
50
and a downstream side of the valve seat
50
. The needle valve has a curved surface
92
, which in the preferred embodiment is a spherical surface although other surfaces may be used, for mating with a circular band on the conical annulus
90
. A further detailed description of the interaction of the curved surface of the needle valve and the conical annulus of the valve seat, in addition to the specifics of the fluid flow develop because of the interaction between these components and the swirl generator, is provided in commonly assigned U.S. Pat. No. 5,875,972, which is expressly incorporated herein in its entirety by reference.
The present invention also includes a method of securing the valve seat
50
to a valve body
38
. The valve seat
50
is initially located within the end of the valve body, which in the preferred embodiment constitutes the outlet
46
of the valve body
38
. After the valve seat
50
is located in the outlet
46
of the valve body
50
, an end section
68
of the valve body
38
is crimped to the valve seat
50
. The valve seat
50
and the valve body
38
are provided with specified chamfers so that when the end section
68
of the valve body
38
is crimped to the valve seat
50
a minimum gap is formed. The valve seat
50
is, preferably, provided with a chamfer of approximately 60° included angle. It is to be understood that a range of angles may be employed for the chamfer of the valve seat, for example, approximately 40°-60° included angle. The pre-crimped end section
68
of the valve body is, preferably, provided with a chamfer of 20° included. The end section
64
of the valve body is, preferably, crimped to the valve seat with approximately a 70° included angle.
After crimping the end section
64
of the valve body
38
to the valve seat
50
, a laser weld strategy is employed to form the hermetic weld joint
66
between the crimped end section
64
of the valve body
38
and the valve seat
50
. A laser weld joint
66
is formed from approximately ⅔ from a portion of the valve body and approximately ⅓ from a portion of the valve seat.
While the 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 invention, as defined in the appended claims and equivalents thereof. Accordingly, it is intended that the invention not be limited to the described embodiments, but that it have the full scope defined by the language of the following claims.
Claims
- 1. A fuel injector comprising:a valve body having an inlet, an outlet, and an axially extending fuel passageway from the inlet to the outlet; an armature proximate the inlet of the valve body; a needle valve operatively connected to the armature; a valve seat proximate the outlet of said valve body; and a fault tolerant structural connection that includes first and second connections between the valve seat and the valve body, the first connection including a crimped end section of the valve body, and the second connection including a hermetic weld.
- 2. The fuel injector of claim 1, wherein the crimped end section of the valve body engages the valve seat and the weld comprises a joint between the valve body and valve seat.
- 3. A fuel injector comprising:a valve body having an inlet, an outlet, and an axially extending fuel passageway from the inlet to the outlet; an armature proximate the inlet of the valve body; a needle valve operatively connected to the armature; a valve seat proximate the outlet of said valve body, the valve seat comprises a chamfer a approximately 60° included angle; and a fault tolerant structural connection between the valve seat and valve body, the fault tolerant structural connection including a crimped end section of the valve body that engages the valve seat and a hermetic seal between the valve body and valve seat, the crimped end section of the valve body comprises a chamfer of approximately 70° included angle.
- 4. The fuel injector of claim 3, wherein the pre-crimped end section of the valve body comprises a chamfer of approximately 20° included angle.
- 5. The fuel injector of claim 2, wherein the weld joint comprises a laser weld joint.
- 6. The fuel injector of claim 5, wherein the laser weld joint comprises a portion of the valve body and a portion of the valve seat.
- 7. The fuel injector of claim 6, wherein the portion of the valve body is greater than the portion of the valve seat.
- 8. The fuel injector of claim 7, wherein the portion of the valve body comprises approximately ⅔ of the laser weld joint and the portion of the valve seat comprises approximately ⅓ of the laser weld joint.
- 9. The fuel injector of claim 8, wherein the valve body comprises 416P70 stainless steel.
- 10. The fuel injector of claim 8, wherein the valve seat comprises 440C carbon steel.
- 11. The fuel injector of claim 1, further comprising a swirl generator proximate the valve seat that allows the fuel to form a swirl pattern on the valve seat.
- 12. The fuel injector of claim 11,wherein the swirl generator comprises at least one flat disk; wherein 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; and wherein the needle valve includes a curved surface that mates with the conical annulus to inhibit fuel flow through fuel passage of the valve seat.
- 13. The fuel injector according to claim 12, wherein the at least one flat disk comprises at least:(1) a guide disk having a perimeter, a central aperture, and at least one fuel passage opening between the perimeter and the central aperture; and (2) a swirl disk having at least one slot extending tangentially from the opening to the central aperture.
- 14. The fuel injector according to claim 12, wherein said curved surface on said needle valve is spherical.
- 15. A method of securing a valve seat to a valve body in a fuel injector comprising: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.
- 16. The method of claim 15, further comprising:providing both the valve seat and valve body with chamfers so that when the end section of the valve seat 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.
- 17. A method of securing a valve seat to a valve body in a fuel injector, the method comprising:providing a valve seat with a chamfer of 60° included angle; providing an end section of a valve body with a chamfer of 20° includes; locating the valve seat within the end section of the valve body; crimping the end section of the valve body to the valve seat with a 70° included angle; and welding the crimped end section of the valve body to the valve seat.
- 18. The method of claim 17, further comprising:employing a laser weld to form the hermetic weld joint between the crimped end section of the valve body and the valve seat.
- 19. The method of claim 18, further comprising:forming the hermetic weld joint with a portion of the valve body and a portion of the valve seat.
- 20. The method of claim 19, further comprising:forming approximately ⅔ of the hermetic weld joint from the portion of the valve body and approximately ⅓ of the hermetic weld joint from the portion of the valve seat.
US Referenced Citations (12)