Information
-
Patent Grant
-
6182646
-
Patent Number
6,182,646
-
Date Filed
Thursday, March 11, 199925 years ago
-
Date Issued
Tuesday, February 6, 200123 years ago
-
Inventors
-
Original Assignees
-
Examiners
- Yuen; Henry C.
- Castro; Arnold
Agents
- Artz & Artz P.C.
- Dziegielewski; Greg
-
CPC
-
US Classifications
Field of Search
US
- 123 56826
- 123 56821
- 251 12915
- 251 12918
- 335 219
- 335 262
- 335 261
- 335 260
- 335 278
- 335 279
-
International Classifications
-
Abstract
A closed-loop controlled system solenoid actuated EGR valve includes an engine mount for attachment to a vehicle engine, a valve housing to which the engine mount is attached, a motor housing positioned above the valve housing, and a sensor housing. The valve housing includes a valve inlet adapted to receive engine exhaust gas and a valve outlet which communicates the engine exhaust gas from the valve inlet to an engine intake system. The motor housing has a bobbin, an armature, and a valve stem disposed in a bore formed therein. The valve stem is in communication with a plunger extending from the sensor housing to monitor the position of the valve stem with respect to the valve seat. A guide bearing is positioned in the housing to guide the armature while a valve stem bearing is positioned in the valve housing to contact and position the valve stem with respect to the valve seat while a valve opening is being closed.
Description
TECHNICAL FIELD
The present invention relates generally to an exhaust gas recirculation valve. More specifically, the present invention relates to an electromechanically actuated exhaust gas recirculation valve for a vehicle engine that provides high performance at low cost and also assists in decreasing harmful emissions.
BACKGROUND OF THE PRESENT INVENTION
Exhaust gas recirculation (“EGR”) valves form an integral part of the exhaust gas emissions control in typical internal combustion engines. EGR valves are utilized to recirculate a predetermined amount of exhaust gas back to the intake system of the engine. The amount of exhaust gas permitted to flow back to the intake system is usually controlled in an open-looped fashion by controlling the flow area of the valve, i.e., the amount of exhaust gas that is permitted to flow through the valve. Such open-loop control makes it difficult to accurately control the exhaust gas flow through the valve over the valve's useful life. This is because the valve has various components that can wear or because vacuum signals which are communicated to such valves will vary or fluctuate over time resulting in the potential contamination of various valve components which could affect the operation of the valve.
Many EGR valves utilize a moveable diaphragm to open and close the valves. However, these valves can lack precision because of the loss of vacuum due to external leakpaths. To overcome the lack of consistently available vacuum to control a movable diaphragm, electrically actuated solenoids have been used to replace the vacuum actuated diaphragm. Moreover, typical vacuum actuated valves can also have problems with accuracy due to their inability to quickly respond based on changes in engine operating conditions. Further, current EGR valves typically have an inwardly opening valve closure element that is moved into its valve housing relative to a cooperating valve seat in order to open the valve. Over the useful life of these valves, carbon can accumulate on the valve closure element and upon its valve seat, thereby preventing the valve from completely closing. The valve closure elements are also positioned within the housing or body of these EGR valves and because it is virtually impossible to clean the valve closure element and the valve seat, contamination thereby necessitates replacement of these integral pollution system components.
Additionally, exhaust gas recirculation valves that require a high force to open the valve, operate through pressure balancing, whether through a diaphragm or other balancing members. Alternatively, too low a force can open the valve allowing exhaust gas to flow through the valve opening when such exhaust gas is not needed. By allowing exhaust gas to act as part of the pressure balance, it necessarily contacts the internal moving parts of the valve causing contaminants to accumulate thereon which can interfere with the proper operation of the valve, as discussed above.
SUMMARY OF THE INVENTION
It is, therefore, an object of the present invention to provide an improved electromechanically actuated EGR valve that is used to meter and control the passage of exhaust gases from an exhaust passage to the intake system of an internal combustion engine.
It is another object of the present invention to provide an electromechanically actuated EGR valve that helps reduce an engine's emissions of environmentally unfriendly elements.
It is yet another object of the present invention to provide an electromechanically actuated EGR valve that helps decrease environmentally unfriendly emissions.
It is a further object of the present invention to provide an EGR valve that has no external leak path and is, therefore, sealed from the atmosphere.
It is still a further object of the present invention to provide an EGR valve that has closed-loop control of the movement of the valve stem and the opening and closing of the valve.
In accordance with the above and other objects of the present invention, a solenoid actuated EGR valve for an engine is disclosed. The EGR valve includes a valve housing, a motor housing, and an engine mount for attaching the EGR valve to the engine. The valve housing includes a valve inlet adapted to receive exhaust gas and a valve outlet adapted to communicate the received exhaust gas to the intake manifold of the engine. The motor housing is positioned above the valve housing and has an electromagnetic mechanism disposed therein, which includes a plurality of wire windings, a bobbin, an armature, and a valve stem in communication with the armature. The armature is moved due to increased current that creates electromagnetic forces created in the magnetic circuit which moves the valve stem with respect to a valve seat that is located in the valve housing around the periphery of a valve opening. A plunger extends from a sensor housing positioned above the motor housing to monitor the position of the valve stem. A guide bearing is disposed within the motor housing and is in communication with the armature to help position the armature concentrically within the magnetic circuit. A valve stem bearing is also positioned within the valve housing to assist in insuring proper closure of the valve in the valve seat as the armature is moving downwardly.
These and other features and advantages of the present invention will become apparent from the following descriptions of the invention, when viewed in accordance with the accompanying drawings and appended claims.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1
is a cross-sectional view of an exhaust gas recirculation valve, including an engine mount, in a closed position in accordance with a preferred embodiment of the present invention; and
FIG. 2
is a cross-sectional view of the exhaust gas recirculation valve of
FIG. 1
, along the line
2
—
2
with the valve in an open position;
FIG. 3
is a cross-sectional view of an exhaust gas recirculation valve, including an engine mount, in accordance with another preferred embodiment of the present invention;
FIG. 4
is a cross-sectional view of an exhaust gas recirculation valve having a diaphragm in accordance with another preferred embodiment of the present invention;
FIG. 5
is a top view illustrating the attachment of an exhaust gas recirculation valve to an engine in accordance with a preferred embodiment of the present invention; and
FIG. 6
is a top view illustrating the attachment of an exhaust gas recirculation valve to an engine in accordance with another preferred embodiment of the present invention.
BEST MODE(S) FOR CARRYING OUT THE INVENTION
FIGS. 1 and 2
illustrate an exhaust gas recirculation (“EGR”) valve
10
in accordance with a preferred embodiment of the present invention. The valve
10
is a solenoid actuated ERG valve, having a motor housing
12
, a valve housing
14
, a sensor housing
16
, and an engine mount
18
.
The motor housing
12
includes an outer shell
20
having a top portion
22
and a bottom portion
24
. The motor housing
12
is preferably comprised of steel, however, any other suitable magnetic material can be utilized. The top portion
22
of the outer shell
20
has an upper peripheral portion
26
that is bent or otherwise formed so as to extend generally inwardly to crimp the sensor housing
16
to the motor housing
12
. An upper seal
28
, such as an O-ring or the like, is preferably positioned at the peripheral connection of the sensor housing
16
and the motor housing
12
to seal the motor housing
12
from the atmosphere and eliminate any leak paths. As shown, the upper seal
28
seals three surfaces from external leaks. Additionally, the upper seal
28
will expand upon increased heat, which will minimize any rattle in the valve
10
and provide improved vibration characteristics.
An armature
30
is disposed within the motor housing
12
and has a top surface
32
and a bottom surface
34
. The armature
30
preferably has a nickel plated surface to provide hardness, durability, and low friction. The armature
30
may also have other coatings that provide similar characteristics, such as chrome. The armature
30
preferably has a hollow pintel valve
35
positioned within a bore
38
formed in the center of the armature
30
. The hollow pintel valve configuration allows for the low transmission of heat to the coil and armature and also improves gas flow, such as when in the position shown in FIG.
3
. The valve stem
36
has a closed upper end
37
that is secured within the bore
38
and may extend above the top surface
32
of the armature
30
. The hollow valve
36
may be attached to the bore
38
in any of a variety of ways. Moreover, the closed upper end
37
of the hollow valve
36
may also be positioned such that its top surface terminates below the top surface
32
of the armature
30
. A valve stem
36
, which is preferably also hollow to reduce the weight of the part is preferably press fit into the bore
38
formed in the center of the armature
30
. This configuration allows the effective length of the valve stem
36
to be changed by how far it is inserted into the armature bore
38
, as is discussed in more detail below. The connection or assembly of the valve stem
36
is less costly and provides a more accurately formed valve as the length of the valve stem is not dependent upon precise tolerances as any excess length valve stem
36
can be accommodated for by the armature bore
38
.
A bobbin
40
holds a plurality of wire windings
42
in the motor housing
12
. The bobbin
40
encapsulates the armature
30
and valve stem
36
. The wire windings
42
are excited by current from a contact or terminal
44
that is positioned within the sensor housing
16
and in communication with the wire windings
42
by a wire
45
or the like. The increased current in the windings
42
is used to move the armature
30
downwardly within the motor housing
12
, thus moving the valve stem
36
correspondingly downward.
A flux return
46
, which is preferably comprised of a magnetic material, is positioned between the upper portion
48
of the bobbin
40
and the outer periphery
50
of the armature
30
. The flux return
46
has an upper portion
52
and a lower portion
54
. A pole piece
56
, having a first portion
58
and a second portion
60
, is anularly positioned between the lower portion
62
of the bobbin
40
and the valve stem
36
and axially below the flux return
46
. A gap
64
is preferably formed between the first portion
58
of the pole piece
56
and the lower portion
54
of the flux return
46
.
An armature bearing
66
is disposed in the motor housing
12
to guide the armature
30
as it travels in response to increased and decreased current in the wire windings
42
. The armature bearing
66
is positioned in the gap
64
and has an upper shoulder portion
68
and a lower shoulder portion
70
. The upper shoulder portion
68
is overlapped by the lower portion
54
of the flux return
46
while the lower shoulder portion
70
of the armature bearing
66
is overlapped by the first portion
58
of the pole piece
56
such that the armature bearing
66
is securely positioned within the motor housing
12
. The armature bearing
66
also has an annular surface
72
which contacts the outer periphery
50
of the armature
30
to guide the armature
30
as it moves linearly within the motor housing
12
. The armature bearing
66
also assists in keeping the armature
30
and thus the valve stem
36
accurately and centrally positioned within the motor housing
12
. Further, the armature bearing
66
helps keep the pole piece
56
and the flux return
46
concentrically positioned. The armature bearing
66
is preferably bronze, however, any other suitable materials can be utilized. The armature bearing
66
is thus positioned within a magnetic flux path created between the pole piece
56
and the flux return
46
.
The bobbin
40
is bounded at its upper portion
48
by the upper portion
52
of the flux return
46
. The bobbin
40
is bounded at its middle portion
76
by the lower portion
54
of the flux return
46
and the first portion
58
of the pole piece
56
. The bobbin
40
is bounded and at its lower portion
62
, by the second portion
60
of the pole piece
56
. The bobbin
40
thus separates the inner surfaces of the pole piece
56
and the flux return
46
from the wire windings
42
. The bobbin
40
has a groove
80
formed in its upper portion
48
for securely holding the wire
45
to the terminal
44
to provide constant electrical contact between the wire windings
42
and the sensor housing
16
and to allow for the energizing of the wire windings
42
.
The armature
30
has a cavity
82
formed in the armature bottom surface
34
which is defined by an armature ear
74
that extends around the periphery of the cavity
82
and contacts the armature bearing
66
. The ear
74
is preferably positioned on the armature
30
as opposed to being positioned on the pole piece
56
for controlling the flux path as has been previously done. The armature
30
is positioned within the motor housing
12
such that when the valve is closed, the lowermost portion
78
of the armature ear
74
is aligned in the same plane as the top of the pole piece
56
. The configuration of the flux return
46
and the pole piece
56
is such that the inclusion of the gap
64
therebetween minimizes the net radial magnetic forces, by limiting the radial forces on the armature
30
and thus the side loading on the armature bearing
66
. The geometry of the armature
30
also provides radial and axial alignment. Additionally, by initially aligning the armature ear
74
with the top of the pole piece
56
, the magnetic flux in the motor housing is limited which allows for larger tolerances which in turn decreases the cost to manufacture the valve
10
. Additionally, by aligning the initial position of the armature
30
with the top
83
of the pole piece
56
, the movement of the armature
30
is limited to its useable range such that the valve
10
may be more accurately controlled.
A biasing spring
84
having an upper surface
86
and a lower surface
88
is disposed within the motor housing
12
. The upper surface
86
of the biasing spring
84
is disposed within the cavity
82
and contacts the armature bottom surface
34
. The lower surface
88
of the biasing spring
84
contacts a partition member
90
and is supported thereon. The partition member
90
has an upper surface
92
, a stepped portion
94
, with a shoulder portion
96
, and an annular surface
98
. The upper surface
92
preferably runs generally parallel with and contacts the second portion
60
of the pole piece
56
to provide support thereto. The lower surface
88
of the biasing spring
84
rests on the shoulder portion
96
of the partition member
90
while the annular surface
98
extends generally downward from the shoulder portion
96
towards the bottom portion
24
of the housing outer shell
20
. The biasing spring
84
acts to urge the armature
30
to its initial position, shown in
FIG. 1
, where the valve
10
is closed. When the valve
10
is opened, due to downward movement of the armature
10
, the biasing spring
84
is compressed, as shown in FIG.
2
.
An annular cavity
100
is formed in the motor housing
12
and is defined by the partition member
90
, the housing outer shell
20
, and the bottom portion
24
of the housing outer shell
20
. A plurality of vent openings
102
are formed in the housing outer shell
20
of the valve
10
to allow cool air to circulate through the annular cavity
74
to cool the valve stem
36
and other components in the motor housing
12
. This arrangement also provides an air gap between the motor housing
12
and the valve housing
14
that will limit the egress of heat from the valve housing
14
to the motor housing
12
. The annular cavity
100
may be formed between the motor housing
12
and valve housing
14
with vent openings
102
communicating therewith.
A lower seal
103
is provided at the juncture between the upper surface
92
of the partition member
90
, the housing outer shell
20
, and the second portion
60
of the pole piece
56
to eliminate any leak path between the annular cavity
100
and the motor housing
12
. The lower seal
103
also seals three surfaces from external leaks and provides improved vibration characteristics when the lower seal
103
expands. The lower portion
24
of the can
20
has a plurality of shear tabs
101
formed therein. The shear tabs
101
extend generally inwardly into the annular cavity
100
and support the partition member
90
. These shear tabs
101
can be formed in subsequent manufacturing processes allowing for inexpensive one-piece manufacturing of the can
20
without the need for additional material to support the partition member
90
. The configuration allows for the inexpensive support of the wire windings
42
and also provides a spring against which the motor housing
12
can be crimped.
The bottom portion
24
of the housing outer shell
20
has a valve stem opening
104
formed therethrough. The valve stem opening
104
is formed in the bottom portion
24
of the outer shell
20
such that the valve stem
36
can pass between the annular surface
98
of the partition member
90
. A valve stem bearing
106
is preferably positioned within the valve stem opening
104
and extends into the valve housing
14
. The valve stem bearing
106
contacts the valve stem
36
when the valve stem
36
is moving upwardly and downwardly within the motor housing
12
to ensure accurate positioning of a valve poppet
132
in a valve seat
120
.
The valve housing
14
is preferably positioned beneath the motor housing
12
and is secured thereto by a plurality of fasteners
108
, such as bolts or the like, which are passed through the bottom portion
24
of the outer shell
20
and into the valve housing
14
. The valve housing
14
includes a top surface
110
, in communication with the motor housing
12
, a bottom surface
112
in communication with an engine manifold, and an outer periphery
114
. A gasket
134
is preferably positioned between the bottom portion
24
of the outer shell
20
and the valve housing
12
to reduce valve noise and vibration. The inclusion of the gasket
134
prevents any metal of the motor housing
12
from contacting any metal from the valve housing
14
and hinders the conductivity of heat and vibration. The only metal to metal contact between the motor housing
12
and the valve housing
14
is through the plurality of fasteners
108
that attach the motor housing
12
to the valve housing
14
. The valve housing
14
includes an inlet passage
116
, a valve opening
118
surrounded by the valve seat
120
, a gas chamber
122
, an exhaust opening
124
, and an exhaust passage
126
.
The valve stem
36
has an upper portion
128
that is partially telescopically received within the armature
30
, and a lower portion
130
positioned within the valve housing
14
. The lower portion
130
of the valve stem
36
has the poppet
132
formed thereon, for communication with the valve seat
120
. The valve stem
36
is secured in the armature
30
, through the valve stem opening
104
formed in the bottom portion
24
of the housing
20
and into contact with the valve seat
120
. The valve stem bearing
106
is preferably positioned within the valve stem opening
104
and helps to accurately position the valve stem
36
and thus the poppet
132
with respect to the valve seat
120
as the valve opening
118
is being opened and closed. When the valve stem
36
is in a fully closed position or is being opened, the valve stem
36
contacts the valve stem bearing
106
to ensure accurate positioning thereof. The valve housing
14
is preferably formed of a metal casting. However, any other suitable material or manufacturing method may be utilized.
A stem shield
136
is preferably positioned within the valve housing
14
. The stem shield
136
has a shoulder portion
138
that is preferably wedged between the valve stem bearing
106
and the valve housing
14
. The stem shield
136
has a passageway
140
formed therethrough for passage of the valve stem
36
. The stem shield
136
prevents contaminants in the exhaust gas that enter the gas chamber
122
through the inlet passage
116
from passing upward into communication with the valve stem bearing
106
. The stem shield
136
may take on a variety of different configurations, depending upon the flow path of the valve, such as shown in
FIGS. 1 and 3
. For example, the stem shield
136
can guide the flow of exhaust gas through the valve, can improve its flow, can increase its flow and/or can direct the flow in a particular direction. The stem shield
136
also protects the valve stem bearing
106
and the valve stem
36
from contamination. In
FIG. 3
, the stem shield has ends
137
that are bent up into the passageway
140
to further restrict the flow of contaminants.
The valve stem bearing
106
has a generally vertical portion
142
and a generally horizontal portion
144
. The generally vertical portion
142
passes through the valve stem opening
104
and contacts the annular surface
98
on one side and the valve stem
36
on its other side. The generally horizontal portion
144
contacts the gasket
134
on one side, the stem shield
136
on its other side, and the valve housing
14
around its periphery.
The sensor housing
16
includes a sensor plunger
146
which extends therefrom. The plunger
146
is designed to contact the closed upper end
37
of the hollow tube
35
which is secured within the bore
38
formed in the armature
30
. The plunger
146
reciprocates upwardly and downwardly as the armature
30
and the valve stem
36
travel within the motor housing
12
due to current changes in the wire windings
42
. The sensor housing
16
transmits current to the wire windings
42
through the terminal
44
based on signals from an external computer. The sensor housing
16
may be any commercially available sensor.
In operation, the EGR valve
10
receives exhaust gases from the engine exhaust transferred by the exhaust inlet passage
116
through the valve opening
118
. The exhaust gas that passes through the valve opening
118
is then passed into the gas chamber
122
within the valve housing
14
. As signals are received by the sensor housing
16
, which indicate certain engine conditions, the current in the bobbin
40
is either increased or decreased to vary the strength of the magnetic field. When engine conditions indicate that the valve opening
118
should be opened, the wire windings
42
are excited with current through the terminal
44
. The increased current in the bobbin
40
increases the strength of the magnetic force and causes the armature
30
to move downwardly within the motor housing
12
causing the poppet
132
to move away from the valve seat
120
thus opening the valve opening
118
.
As the armature
30
is moved downwardly, the armature bearing
66
keeps the armature
30
axially and radially aligned in the motor housing
12
. As the armature
30
moves downward, the valve stem
36
, which is secured within the armature bore
38
, also moves downwardly. During the downstroke, the valve stem
36
contacts the valve stem bearing
106
. The valve stem
36
is illustrated in a closed position in FIG.
1
and in an open position in FIG.
2
. The exhaust gas that passes to the gas chamber
122
then exits through the exhaust passage
126
to the intake system of a spark ignition internal combustion engine.
The sensor housing
16
is provided with the proper amount of current to allow the desired amount of exhaust gas through the valve opening
118
and back to the engine. The sensor housing
16
allows for closed loop control between the valve stem
36
and an associated ECU. This amount is predetermined depending upon the load and speed of the engine as is well known in the art. The sensor located within the sensor housing
16
also provides closed-loop feedback to assist in determining the position of the valve stem
36
and to regulate the amount of exhaust gas that flows through the valve opening
118
. Upon transfer of the desired amount of exhaust gas through the valve
10
back to the engine, the current transmitted through the terminal
44
to the wire windings
42
decreases. The magnetic force is thus decreased allowing the armature
30
to return to its initial position by the biasing spring
84
.
As the armature
30
and the valve stem
36
travel upwardly, the valve poppet
132
re-engages the valve seat
120
and closes off the flow of exhaust gas through the valve opening
118
. As the valve stem
36
travels upwardly, the valve stem bearing
106
guides the valve stem
36
and keeps it accurately aligned to ensure proper closure of the valve opening
118
. At the same time, the plunger
146
moves upwardly by the hollow tube
35
with which it is in contact to provide an indication of the position of the valve stem
36
with respect to the valve seat
120
. Metering and controlling of the exhaust passage in this manner helps in reducing the engine's emissions of harmful oxides of nitrogen.
The engine mount
18
is preferably mounted to the engine block through a plurality of mount holes
148
by fasteners, such as bolts or the like. As shown in
FIG. 1
, in one embodiment, the engine mount
18
is attached to or incorporated into the valve housing
14
. In another preferred embodiment, shown in
FIG. 3
, the engine mount
18
is incorporated into or otherwise attached to the motor housing
12
. The embodiment shown in
FIG. 3
allows the valve housing
12
to be further consolidated, therefore decreasing the size of the valve and reducing the cost of manufacture. It should be understood that various other configurations and attachment points may be incorporated into the engine mount
18
.
As shown in
FIGS. 5 and 6
, the valve
10
may be attached through port holes
148
to the engine casting
150
in a variety of ways. In the embodiment shown in
FIG. 5
, the valve
10
is nested directly into the engine casting
150
which allows for the transfer of heat from the valve
10
into the engine casting
150
. The engine casting
150
therefore acts as a heat sink. Additionally, the nesting of the valve
10
in this manner assists in reducing vibration. As shown, the engine mount
18
is used to secure the valve
10
and its components to the engine casting
150
. In the embodiment shown in
FIG. 6
, an auxiliary spacer
152
is provided which is for use with a flat engine mount. The auxiliary spacer
152
is placed between the valve
10
and the engine mount
18
such that the bolts will pass through the engine mount
18
, the spacer
152
, and into the engine casting
150
. In this embodiment, the engine mount
18
contacts the outer can
20
and the valve housing
14
to allow for heat transfer through the spacer
152
and into the engine casting
150
. The auxiliary spacer
152
also helps minimize vibration.
Additionally, a bracket tab
154
is disposed below the outer can
20
. The bracket tab
154
fits into a cut-out formed in the gasket
134
and engages a notch
156
cast into the valve housing
14
, thus preventing the valve
10
from moving axially or radially relative to the bracket tab
154
. The bracket tab
154
also improves the heat conduction from the valve to the gasket
134
thus minimizing any heat transfer to the motor housing
12
.
As shown in
FIG. 4
, an alternative embodiment of the preferred EGR valve is disclosed. The valve
10
includes a motor housing
12
and a valve housing
14
. The structure of the valve housing
14
is the same as in the prior embodiments, while the structure of the motor housing
12
is generally the same except that a diaphragm
158
is disposed between the motor housing
12
and the sensor housing
16
. Specifically, a diaphragm
158
is captured between the flux return
46
and the sensor housing
16
. The diaphragm
158
has an outer periphery
160
that is positioned in a similar location as the upper seal
28
in the prior embodiments. The diaphragm
158
has an inner periphery
162
which is secured to the top surface
32
of the armature
30
by an end cap
164
. The end cap
164
has a protrusion
166
which extends into the bore
38
of the armature
30
thus securing it thereto. The end cap
164
is in communication with the plunger
146
at a top surface
168
to provide the same control over the armature
30
and the valve stem
36
, as described above. The armature
30
has a different configuration for its top surface
32
so as to engage the end cap
164
. The diaphragm
158
acts as a seal between the motor housing
12
and the sensor housing
16
. The diaphragm
158
seals the connection between the motor housing
12
and the sensor housing
16
from the atmosphere and also provides improved vibration characteristics.
Having now fully described the invention, it will be apparent to one of ordinary skill in the art that many changes and modifications can be made thereto without departing from the spirit or scope of the invention as set forth herein.
Claims
- 1. An exhaust gas recirculation valve for an engine, comprising:an engine mount for attaching said valve to said engine; a valve housing, including a valve inlet adapted to receive exhaust gas, a valve seat surrounding a valve opening, through which said received exhaust gas passes, and a valve outlet adapted to communicate said received exhaust gas to an engine intake; a motor housing having disposed therein a solenoid coil, an armature, and a valve stem in communication with said armature and linearly moveable so as to open and close the communication between said valve inlet and said engine intake; a sensor housing having an electromagnetic mechanism therein to monitor the position of said valve stem and thus said armature; a guide bearing disposed within said motor housing and engageable with an outside surface of said armature to accurately position said armature concentrically within said motor housing; and a valve stem bearing to assist in accurately closing a valve poppet, positioned on said valve stem, in said valve seat to prevent further communication between said valve inlet and said engine intake.
- 2. The valve of claim 1, further comprising a computer in communication with said valve, said computer providing signals to provide increased current to said solenoid coil depending upon engine conditions to move said armature and said valve stem within said motor housing.
- 3. The valve of claim 1, further comprising a stem shield surrounding said valve stem to prevent dirt and other contaminants from entering the motor housing.
- 4. The valve of claim 1, further comprising an annular cavity formed in a can between said motor housing and said valve housing.
- 5. The valve of claim 1, wherein a plurality of vent holes are formed in said annular cavity to allow air to circulate between said valve housing and said motor housing and to prevent the transfer of heat therebetween.
- 6. The valve of claim 1, wherein said armature bearing is positioned within said motor housing between a flux return and a pole piece within magnetic flux path.
- 7. The value of claim 1, wherein said valve is sealed from the atmosphere in that it does not have any external leakpaths.
- 8. The valve of claim 1, further comprising a biasing spring disposed within said motor housing and having a top portion in communication with a bottom surface of said armature for biasing said armature upward to return said valve stem into contact with said valve seat.
- 9. The valve of claim 8, wherein said biasing spring has a bottom portion in communication with a stamped part to support said biasing spring thereon.
- 10. The valve of claim 9, wherein said stamped part helps support said solenoid coil in said motor housing.
- 11. An exhaust gas recirculation valve, comprising:a motor housing including, a bobbin, an armature having a bore formed therein, and a valve stem, said valve stem secured within said bore; a valve housing including a valve inlet adapted to receive exhaust gas, a valve seat, a valve poppet located at an end of said valve stem to engage and disengage said valve seat to open and close a valve opening, thereby allowing or preventing said exhaust gas to pass to an engine intake; a sensor housing, including a plunger extending therefrom into said motor housing, said plunger in communication with said valve stem to monitor the position thereof; and an armature bearing that is positioned within said motor housing and is in communication with an outer surface of said armature to position said valve stem as said valve opening is being exposed and wherein said armature bearing is positioned within said motor housing between a flux return and a pole piece.
- 12. The valve of claim 11, further comprising is a valve stem bearing that is positioned in an opening between said motor housing and said valve housing and contacts said valve stem only as it moves in response to movement of said armature.
- 13. The valve of claim 12, further comprising:an engine mount for attaching said valve to a vehicle engine.
- 14. The valve of claim 13, further comprising a stem shield positioned in said valve housing and around said valve stem to prevent dirt and other contaminants from passing through said opening between said motor housing and said valve housing.
- 15. The valve of claim 13, further comprising an annular cavity in said motor housing for receipt of air to cool said valve stem.
- 16. The valve of claim 15, wherein at least one vent opening is formed in said motor housing to allow air to flow into and out of said annular cavity.
- 17. An exhaust gas recirculation valve for accurately controlling the flow of engine exhaust gas to an engine intake, comprising:an outer can portion defining a motor housing therein and having an opening formed in a bottom surface; a sensor housing secured to said valve and disposed above said motor housing; an armature disposed within said motor housing and in electromagnetic communication with a solenoid coil disposed therearound, said armature having a bore formed therein; a valve housing disposed beneath said outer can portion, said valve housing including an exhaust gas inlet passage, a valve opening in communication with said exhaust gas inlet passage, a valve seat surrounding said valve opening, and an exhaust gas exit passage; a flexible diaphragm disposed between said motor housing and said sensor housing said diaphragm having an outer periphery positioned at a junction defined by said outer can portion, said motor housing, and said sensor housing to prevent any leakpaths to atmosphere at said junction; a valve stem having an upper portion and a lower portion, said upper portion fixed within said armature bore and said lower portion having a poppet formed thereon for communication with said valve seat, said valve stem passing through said opening in said outer can bottom surface; and a plunger extending from said sensor housing and in communication with said valve stem to monitor the position of said valve stem with respect to said valve seat.
- 18. The exhaust gas recirculation valve of claim 17, further comprising a valve stem shield in said valve housing and disposed around a portion of said valve stem.
- 19. The exhaust gas recirculation valve of claim 17, further comprising an engine mount to attach said valve to an engine.
- 20. The exhaust gas recirculation valve of claim 19, wherein a spacer is disposed between said valve and said engine when said valve is mounted to said engine.
- 21. The exhaust gas recirculation valve of claim 19, further comprising:a flux return disposed around a portion of said solenoid coil.
- 22. The exhaust gas recirculation valve of claim 21, further comprising:a pole piece disposed around another portion of said solenoid coil, said pole piece positioned below said flux return such that said pole piece and said flux return do not meet.
- 23. The exhaust gas recirculation valve of claim 22, wherein a gap is formed between said pole piece and said flux return.
- 24. The exhaust gas recirculation valve of claim 23, further comprising a bearing positioned within said gap, said bearing having an outwardly extending annular surface that contacts said armature to assist in accurately positioning said valve stem as said armature moves downwardly.
- 25. The exhaust gas recirculation valve of claim 24, wherein said armature further comprises an ear portion that is initially aligned with a top surface of said pole piece.
- 26. The exhaust gas recirculation valve of claim 25, further comprising a hollow tube secured within said armature bore, said hollow tube having a closed top surface in communication with said plunger and an open bottom for receiving said valve stem therein.
- 27. The exhaust gas recirculation valve of claim 26, wherein said closed top surface is positioned above a top surface of said armature.
- 28. An exhaust gas recirculation valve for accurately controlling the flow of engine exhaust gas to an engine intake, comprising:an outer can portion defining a motor housing therein and having an opening formed in a bottom surface; a sensor housing secured to said valve and disposed above said motor housing; an armature disposed within said motor housing and in electromagnetic communication with a solenoid coil disposed therearound, said armature having a bore formed therein; a valve housing disposed beneath said outer can portion, said valve housing including an exhaust gas inlet passage, a valve opening in communication with said exhaust gas inlet passage, a valve seat surrounding said valve opening, and an exhaust gas exit passage; a seal positioned at a junction between said outer can portion, said motor housing, and said sensor housing to prevent any leakpaths to atmosphere at said junction; a valve stem having an upper portion and a lower portion, said upper portion fixed within said armature bore and said lower portion having a poppet formed thereon for communication with said valve seat, said valve stem passing through said opening in said outer can bottom surface; and a plunger extending from said sensor housing and in communication with said valve stem to monitor the position of said valve stem with respect to said valve seat.
- 29. An exhaust gas recirculation valve for accurately controlling the flow of engine exhaust gas to an engine intake, comprising:an outer can portion defining a motor housing therein and having an opening formed in a bottom surface; a sensor housing secured to said valve and disposed above said motor housing; an armature disposed within said motor housing and in electromagnetic communication with a solenoid coil disposed therearound, said armature having a bore formed therein; a valve housing disposed beneath said outer can portion, said valve housing including an exhaust gas inlet passage, a valve opening in communication with said exhaust gas inlet passage, a valve seat surrounding said valve opening, and an exhaust gas exit passage; a valve stem having an upper portion and a lower portion, said upper portion fixed within said armature bore and said lower portion having a poppet formed thereon for communication with said valve seat, said valve stem passing through said opening in said outer can bottom surface; a plunger extending from said sensor housing and in communication with said valve stem to monitor the position of said valve stem with respect to said valve seat; and a pole piece disposed around another portion of said solenoid coil, said pole piece positioned below said flux return such that said pole piece and said flux return do not meet such that a gap is formed between said pole piece and said flux return; wherein said motor housing further comprises a partition member positioned below said solenoid coil and in contact with said sprig to support said solenoid coil in said motor housing; wherein said pole piece, said partition member, and said outer can portion meet at a junction and wherein a seal is positioned at said junction to prevent any leakpaths to atmosphere.
- 30. The exhaust gas recirculation valve of claim 29, wherein an annular cavity is formed in said motor housing by said partition member.
- 31. The exhaust gas recirculation valve of claim 30, wherein at least one vent opening is formed in said can to allow air to flow into and out of said annular cavity from atmosphere.
- 32. The exhaust gas recirculation valve of claim 31, further comprising a gasket positioned between said outer can and said valve housing to prevent the transfer of heat between said housings.
- 33. An exhaust gas recirculation valve for accurately controlling the flow of engine exhaust gas to an engine intake, comprising:a motor portion, including an outer can portion, a solenoid coil disposed within said outer can portion, and an armature in electromagnetic communication with said solenoid coil; a valve housing including an exhaust gas inlet passage, a valve opening in communication with said exhaust gas inlet passage. a valve seat surrounding said valve opening, and an exhaust gas exit passage; a valve stem extending between said motor housing and said valve housing and having an upper portion secured to said armature and a lower portion in communication with said valve opening; a sensor housing secured to said valve and in communication with said motor housing to monitor the position of said valve stem with respect to said valve seat; and an annular cavity formed in said motor housing to prevent heat from said valve housing from transforming to said motor housing; an armature bearing that is positioned within said motor housing and is in communication with an outer surface of said armature to position said valve stem as said valve opening is being exposed and wherein said armature bearing is positioned within said motor housing between a flux return and a pole piece.
- 34. The valve of claim 33, further comprising:at least one vent opening formed in said can to allow air to flow from atmosphere into and out of said annular cavity.
- 35. The valve of claim 33, wherein said sensor housing monitors the position of said valve stem by a plunger extending from said sensor housing that reciprocates in response to movement of said valve stem.
- 36. The valve of claim 33 wherein said valve is nested directly into an engine casting to minimize vibration and allow for heat transfer from the valve to said casting.
- 37. The valve of claim 33, further comprising an annular bearing positioned within said motor housing to contact said armature and keep said armature aligned as said valve stem moves linearly with respect to said motor housing.
- 38. The valve of claim 37, further comprising a valve stem bearing designed to contact said valve stem as said valve opening is being closed to assist in properly aligning a valve poppet formed on said lower portion of said valve stem with respect to said valve seat.
- 39. The valve of claim 34, wherein said annular cavity is defined between a partition and said outer can.
- 40. The valve of claim 39, wherein a plurality of sheer tabs are formed in said outer can around said annular cavity to support said partition.
- 41. The valve of claim 40, wherein said partition supports said solenoid coil and thus said sheer tabs support said solenoid coil.
US Referenced Citations (19)