Information
-
Patent Grant
-
6378509
-
Patent Number
6,378,509
-
Date Filed
Tuesday, June 13, 200024 years ago
-
Date Issued
Tuesday, April 30, 200222 years ago
-
Inventors
-
Original Assignees
-
Examiners
- Yuen; Henry C.
- Castro; Arnold
Agents
-
CPC
-
US Classifications
Field of Search
US
- 123 56812
- 123 56824
- 060 6052
- 137 625
- 137 6252
-
International Classifications
-
Abstract
A multifunction valve, particularly suited for use in an internal combustion engine, provides adjustable EGR thereto. The internal combustion engine has a block defining a plurality of combustion cylinders, each combustion cylinder of the plurality of combustion cylinders having a displacement volume. An intake manifold is fluidly connected to the block to supply combustion air to each combustion cylinder. The intake manifold has an air intake port and a first EGR inlet port. A secondary exhaust manifold is fluidly coupled to at least one of the plurality of combustion cylinders. The secondary exhaust manifold has an exhaust outlet port. A multipurpose valve has a first valve inlet port, a waste gas outlet port and a first EGR outlet port, wherein the first valve inlet port is fluidly connected to the exhaust outlet port of the secondary exhaust manifold, the waste gas outlet port is in communication with the atmosphere, and the first EGR outlet port is fluidly coupled to the first EGR inlet port of the intake manifold.
Description
TECHNICAL FIELD
The present invention relates to an exhaust gas recirculation system for an internal combustion engine, and, more particularly, to an exhaust gas recirculation system having a multifunction valve.
BACKGROUND ART
An exhaust gas recirculation (EGR) system is used for controlling the generation of undesirable pollutant gases and particulate matter in the operation of internal combustion engines. Such systems have proven particularly useful in internal combustion engines used in motor vehicles such as passenger cars, light duty trucks, and other on-road motor equipment.
EGR systems primarily recirculate the exhaust gas by-products into the intake air supply of the internal combustion engine. The exhaust gas which is reintroduced to the engine cylinder reduces the concentration of oxygen therein, which in turn lowers the maximum combustion temperature within the cylinder and slows the chemical reaction of the combustion process, decreasing the formation of nitrous oxides (NOx). Furthermore, the exhaust gases typically contain unburned hydrocarbons which are burned on reintroduction into the engine cylinder, which further reduces the emission of exhaust gas by-products which would be emitted as undesirable pollutants from the internal combustion engine.
Some internal combustion engines include turbochargers to increase engine performance, and are available in a variety of configurations. When utilizing EGR in a turbocharged diesel engine, the exhaust gas to be recirculated is preferably removed upstream of the exhaust gas driven turbine associated with the turbocharger. In many EGR applications, the exhaust gas is diverted by a poppet-type EGR valve directly from the exhaust manifold. The percentage of the total exhaust flow which is diverted for introduction into the intake manifold of an internal combustion engine is known as the EGR rate of the engine.
The reintroduction of exhaust gases will occur naturally when the exhaust manifold pressure is higher than the turbocharger boost pressure. In a low pressure system, the pressure difference simply pushes At the exhaust gas into the air intake before the turbocharger compressor. The disadvantage of this approach is the potential fouling of the turbocharger compressor and the air-to-air intercooler of the engine, if so equipped.
High pressure systems typically pump exhaust gas directly into the intake manifold of the engine. However, when such a turbocharged engine operates under lower speed and high torque conditions, the boost pressure is higher than the exhaust manifold pressure and recirculation of exhaust gasses is not possible. Earlier approaches to address this problem have included using devices such as back pressure valves, restrictive turbines, throttle valves and venturi inlet systems. Each can be used to improve the back pressure to boost pressure gradient to some degree, but each approach results in increased fuel consumption.
In controlling EGR, simple valves are sometimes used to direct the flow of exhaust gases for EGR, but such valves are not readily adaptable to accommodate sophisticated EGR system designs. Also, while multi-port valves, such as the valve disclosed in U.S. Pat. No. 3,083,693, have been used in relatively stable environments, commercially available versions of such valves are generally inadequate to handle the harsh environment or the control complexity of sophisticated EGR systems.
The present invention is directed to overcoming one or more of the problems as set forth above.
DISCLOSURE OF THE INVENTION
In one aspect of the invention, an internal combustion engine provides an intake manifold fluidly connected to a block to supply combustion air to each combustion cylinder. The intake manifold has an air intake port and a first EGR inlet port. A secondary exhaust manifold is fluidly coupled to at least one of the plurality of combustion cylinders. The secondary exhaust manifold has an exhaust outlet port. A multipurpose valve has a first valve inlet port, a waste gas outlet port and a first EGR outlet port, wherein the first valve inlet port is fluidly connected to the exhaust outlet port of the secondary exhaust manifold, the waste gas outlet port is in communication with the atmosphere, and the first EGR outlet port is fluidly coupled to the first EGR inlet port of the intake manifold.
In another aspect of the invention, a multifunction valve for adjusting EGR in an internal combustion engine provides a valve body having a plurality of cavities; a valve cap defining an exhaust gas pocket; and a rotor having a first surface, a second surface, a selection port and an air pocket defined by the first surface.
In another aspect of the invention, a method of operating a multifunction valve in an EGR system for an internal combustion engine which generates exhaust gases provides the steps of: operating the multifunction valve in a first position to supply exhaust gas from a second exhaust manifold to a first exhaust manifold; and operating the multifunction valve in a second position to supply a portion of the exhaust gas from the second exhaust manifold to the first exhaust manifold and to at least partially open a waste port to waste a portion of the exhaust gases.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1
is a schematic illustration of an internal combustion engine including the EGR system of the present invention;
FIG. 2
is a schematic illustration of a multifunction valve of the present invention;
FIG. 3
is a front exploded view of the multifunction valve schematically illustrated in
FIG. 2
; and
FIG. 4
is a rear exploded view of a portion of the multifunction valve depicted in FIG.
3
.
BEST MODE FOR CARRYING OUT THE INVENTION
Referring
FIG. 1
, there is shown a schematic representation of an embodiment of an internal combustion engine
10
of the present invention. Internal combustion engine
10
generally includes a block
12
, a cylinder head
14
, a first exhaust manifold
16
, a second exhaust manifold
18
, a turbocharger
20
, an intake manifold
22
and an EGR system
24
.
Block
12
defines a plurality of combustion cylinders
26
individually identified as cylinders
1
to N. The number N of combustion cylinders
26
may be selected dependent upon a specific application. For example, block
12
may include six, ten or twelve combustion cylinders
26
, in which case N=6,10,or 12, respectively. Each combustion cylinder
26
has a displacement volume which is the volumetric change within each combustion cylinder
26
as an associated piston (not shown) moves from a bottom dead center to a top dead center position, or vice versa. The displacement volume may be selected dependent upon the specific application of internal combustion engine
10
. The sum of the displacement volumes for each of combustion cylinders
26
defines a total displacement volume for internal combustion engine
10
.
Cylinder head
14
is connected to block
12
in a manner known to those skilled in the art, and is shown with a section broken away to expose block
12
. As each of the pistons moves to its respective top dead center position, each piston and the cylinder head
14
define a combustion chamber therebetween. In the embodiment shown, cylinder head
14
is a single cylinder head and includes a plurality of exhaust valves (not shown) and a plurality of intake valves (not shown). Exhaust manifolds
16
,
18
and intake manifold
22
are connected to cylinder head
14
, and are fluidly coupled to the plurality of combustion cylinders
26
.
Exhaust manifold
16
includes cylinder ports fluidly connected to receive combustion products from cylinders
1
-to-(N−1) of combustion cylinders
26
, and exhaust manifold
18
is fluidly connected to receive combustion products from cylinder N of combustion cylinders
26
. Exhaust manifold
16
includes an exhaust outlet port
28
and a fluid inlet port
30
. Exhaust manifold
18
includes an exhaust outlet port
32
.
Turbocharger
20
includes a turbine
40
and a compressor
42
. Turbine
40
is driven by the exhaust gases which flow from exhaust outlet port
28
of exhaust manifold
16
. Turbine
40
is coupled with compressor
42
via a shaft
44
and rotatably drives compressor
42
. Turbine
40
includes an exhaust gas inlet
46
and an exhaust gas outlet
48
. Exhaust gas inlet
46
is connected to exhaust outlet port
28
of exhaust manifold
16
via fluid conduit
50
. Exhaust gas outlet
48
of turbine
40
is connected to an exhaust pipe
52
, which in turn is in fluid communication with the atmosphere for expelling exhaust gases.
Compressor
42
receives combustion air (as indicated by arrow
56
) through compressor inlet
58
from the ambient environment and provides compressed combustion air through compressor outlet
60
via fluid conduit
62
to an air intake port
64
of intake manifold
22
. Alternatively, an air cooler (not shown) may be inserted between compressor
42
and intake port
64
to cool the combustion air prior to delivery to intake manifold
22
.
Intake manifold
22
further includes a hot EGR inlet port
66
, a cold EGR inlet port
68
and an air outlet port
70
.
EGR system
24
includes a multifunction valve
72
, a heat exchanger
74
, an actuator
76
, an EGR controller
78
, and a sensor assembly
80
.
Multifunction valve
24
includes valve inlet ports
82
and
84
and valve outlet ports
86
,
88
,
90
, and
92
. Valve inlet port
82
is connected to exhaust outlet port
32
of exhaust manifold
18
via a fluid conduit
94
. Valve inlet port
84
is connected to air outlet
96
of heat exchanger
74
via conduit
98
. Valve outlet port
86
is connected to fluid inlet port
30
of exhaust manifold
16
via fluid conduit
100
. Valve outlet port
88
is connected to exhaust pipe
52
via fluid conduit
102
. Valve outlet port
90
is connected to hot EGR inlet port
66
of intake manifold
22
via fluid conduit
104
. Valve outlet port
92
is connected via fluid conduit
106
to EGR inlet
108
of heat exchanger
74
.
Heat exchanger
74
also includes an air inlet
110
which is connected within heat exchanger
74
to air outlet
96
. Heat exchanger
74
further includes an EGR outlet
112
which is connected within heat exchanger
74
to EGR inlet
108
. Air inlet
110
of heat exchanger
74
is connected via fluid conduit
114
to air outlet port
70
of intake manifold
22
. EGR outlet
112
of heat exchanger
74
is connected via fluid conduit
116
to cold EGR inlet port
68
of intake manifold
22
. Thus, in general, heat exchanger
74
is a dual path heat exchanger including at least one fluid passageway through which non-compressed exhaust gas flows, and at least one fluid passageway through which intake manifold air flows. Optionally, cooling air, or engine coolant, flows around the fluid passageways to cool the exhaust gas and air transported through the passageways.
For sake of clarity, each conduit shown in
FIG. 1
includes an arrow head which depicts the general fluid flow direction associated therewith.
Multifunction valve
72
includes a plurality of operating positions which are selectable via actuator
76
based upon control commands supplied by EGR controller
78
in view of sensor signals received from sensor assembly
80
. Preferably, multifunction valve
72
is a rotary valve having a rotatable shaft
118
which is mechanically coupled to actuator
76
. Actuator
76
is electrically connected to EGR controller
78
via electrical cable
120
. EGR controller
78
is electrically connected to sensor assembly
80
via electrical cable
122
.
Preferably, EGR controller
78
includes a microprocessor having an associated.memory, and has preprogrammed instructions stored in the memory. Also preferably, the preprogrammed instructions can be modified by connecting EGR controller
78
to an input device (not shown), such as a key pad or key board. EGR controller
78
receives sensor input signals from sensor assembly
80
via electrical cable
122
, and executes the preprogrammed instructions to effect the generation of appropriate control signals for use in controlling a rotational displacement of actuator
76
, which in turn controls a rotational displacement of shaft
118
of multifunction valve
72
.
FIG. 2
schematically illustrates a preferred embodiment of multifunction valve
72
. As shown, multifunction valve
72
includes five operating positions which result in corresponding valve internal configurations
123
,
124
,
126
,
128
and
130
. When multifunction valve
72
is operated to a first position, corresponding to a first internal configuration
123
, inlet port
82
is connected to outlet port
86
, and no other internal connections are made. When multifunction valve
72
is operated to a second position, corresponding to a second internal configuration
124
, inlet port
82
is connected to outlet ports
86
and
88
, and no other internal connections are made. When multifunction valve
72
is operated to a third position, corresponding to a third internal configuration
126
, inlet port
82
is connected to outlet port
90
, and no other internal connections are made. When multifunction valve
72
is operated to a fourth position, corresponding to a fourth internal configuration
128
, inlet port
82
is connected to outlet port
92
, inlet port
84
is connected to outlet port
86
, and no other internal connections are made. When multifunction valve
72
is operated to a fifth position, corresponding to a fifth internal configuration
130
, inlet port
82
is connected to outlet
92
, inlet port
84
is connected to outlet ports
86
,
88
, and no other internal connections are made.
FIGS. 3 and 4
show front and rear, respectively, perspective exploded views of multifunction valve
72
, as schematically illustrated in FIG.
2
. Multifunction valve
72
includes a valve body
132
, a valve cap
134
and a valve rotor
136
.
Referring to
FIG. 4
in relation to
FIG. 3
, valve body
132
includes an exhaust gas cavity
138
in fluid communication with outlet port
86
via intermediate connection ports
140
,
142
; a waste exhaust gas cavity
144
in fluid communication with outlet
88
; a hot air cavity
146
in fluid communication with inlet port
84
; an exhaust gas cavity
148
in fluid communication with outlet
92
; and an exhaust gas cavity
150
in fluid communication with outlet port
90
.
Referring to
FIG. 3
, valve cap
134
defines an exhaust gas pocket
152
which is in fluid communication with inlet port
82
. Valve rotor
136
generally separates valve body
132
from valve cap
134
, except for permitting a fluid flow from valve cap
134
to valve body
132
via selection port
154
in valve rotor
136
. Valve rotor
136
includes a first surface
156
positioned to face valve body
132
and includes a second surface
158
which is positioned to face exhaust gas pocket
152
of valve cap
134
. Valve rotor
136
further includes an air pocket, or cavity,
160
which is defined by surface
156
. Selection port
154
and air pocket
160
combine to effect the various internal configurations
123
,
124
,
126
,
128
,
130
of valve
72
, as depicted in
FIG. 2
, which are associated with a selected rotary position of valve rotor
136
.
Industrial Applicability
During use, EGR controller
78
receives sensor input signals from sensor assembly
80
via electrical cable
122
, and executes the preprogrammed instructions to effect the generation of appropriate control signals for use in controlling a rotational displacement of actuator
76
, which in turn controls a rotational displacement of shaft
118
of multifunction valve
72
. Sensor assembly
76
is adapted, for example, to monitor the status of one or more of: CO
2
content of exhaust gas, NO
x
content of exhaust gas, O
2
content of exhaust gas, EGR air flow rate, engine speed, and altitude. Multifunction valve
72
is operable among a plurality of operating positions corresponding to those shown in FIG.
2
.
When operating multifunction valve
72
in position
1
, corresponding to internal valve configuration
123
, exhaust gases are supplied from second exhaust manifold
18
to first exhaust manifold
16
. Position
1
is selected by EGR controller when no EGR is desired, and it is desired to supply a full flow of all available exhaust gases from exhaust manifolds
16
,
18
to turbine
40
of turbocharger
20
.
When operating multifunction valve
72
in position
2
, corresponding to internal configuration
124
, at least a portion of the exhaust gas from second exhaust manifold
18
is diverted to first exhaust manifold
16
, and a waste port
88
is at least partially opened to waste a portion of the exhaust gases of the internal combustion engine
10
to the atmosphere via exhaust pipe
52
. Position
2
is selected by EGR controller when no EGR is desired, and it is desired to supply a part of the full flow of exhaust gases from exhaust manifolds
16
,
18
to turbine
40
of turbocharger
20
, while wasting a portion of the full flow of exhaust gases to limit the revolution velocity of turbocharger turbine
40
to prevent turbocharger over speed and/or control the level of the boost pressure in the inlet manifold
22
.
When operating multifunction valve
72
in position
3
, corresponding to internal configuration
126
, non-cooled (i.e., hot) exhaust gas from second exhaust manifold
18
is delivered directly to intake manifold
22
via fluid conduit
104
. Position
3
is selected to lower particulate content in the exhaust gases generated at low load conditions, and to lessen oil or fuel fouling of heat exchanger
74
in the cooler operating ranges of internal combustion engine
10
by bypassing heat exchanger
74
altogether.
When operating multifunction valve
72
in position
4
, corresponding to internal configuration
128
, exhaust gas from exhaust manifold
18
is supplied to heat exchanger
74
, which in turn provides cooled exhaust gas to intake manifold
22
via fluid conduit
116
. Also, air received from intake manifold
22
via fluid conduit
114
, heat exchanger
74
and fluid conduit
98
is supplied to first exhaust manifold
16
via fluid conduit
100
. Position
4
is selected to maintain mass flow to turbocharger
20
during high load conditions detected by EGR controller
78
, while providing cooled EGR to prevent overheating of internal combustion engine
10
and to obtain optimum engine efficiency.
When operating multifunction valve
72
in position
5
, corresponding to internal configuration
130
, cooled EGR is provided by supplying exhaust gas from exhaust manifold
18
to heat exchanger
74
, which in turn supplies cooled exhaust gases to intake manifold
22
. Air received from intake manifold
22
is supplied to first exhaust manifold
16
, and waste port
90
is at least partially opened to waste a portion of the exhaust gases received from exhaust manifold
18
and/or exhaust manifold
16
. Position
5
is selected to maintain mass flow to turbocharger
20
during high load conditions detected by EGR controller
78
, while providing cooled EGR to prevent overheating of internal combustion engine
10
and to obtain optimum engine efficiency, and also while wasting a portion of the full flow of exhaust gases to limit the revolution velocity of turbocharger turbine
40
to prevent turbocharger over speed or to control the boost level in the intake manifold.
By utilizing a multifunction valve
72
, EGR system
24
of the invention advantageously removes the waste gate from the turbocharger to provide a system cost savings and an improved apparatus for controllably wasting gas so as to prevent turbocharger over speed, both during EGR and in the absence of EGR. In addition, the invention advantageously provides both hot and cooled EGR to internal combustion engine
10
to permit the use of the EGR system over a broader operating range of engine, as compared to prior EGR systems.
Other aspects, objects and advantages of this invention can be obtained from a study of the drawings, the disclosure and the appended claims.
Claims
- 1. An internal combustion engine, comprising:a block defining a plurality of combustion cylinders, each combustion cylinder of said plurality of combustion cylinders having a displacement volume; an intake manifold fluidly connected to said block to supply combustion air to said each combustion cylinder, said intake manifold having an air intake port and a first EGR inlet port; a secondary exhaust manifold fluidly coupled to at least one of said plurality of combustion cylinders, said secondary exhaust manifold having an exhaust outlet port; and a multipurpose valve having a first valve inlet port, a waste gas outlet port and a first EGR outlet port, said first valve inlet port being fluidly connected to said exhaust outlet port of said secondary exhaust manifold, said waste gas outlet port being in communication with the atmosphere, and said first EGR outlet port being fluidly coupled to said first EGR inlet port of said intake manifold.
- 2. The internal combustion engine of claim 1, including:a heat exchanger having an EGR gas inlet and an EGR gas outlet; said intake manifold having a second EGR inlet port fluidly connected with said EGR gas outlet of said heat exchanger; and said multipurpose valve having a second EGR outlet port fluidly connected to said EGR gas inlet of said heat exchanger.
- 3. The internal combustion engine of claim 2, wherein said heat exchanger having an air inlet and an air outlet, said intake manifold having an air outlet port fluidly connected with said an air inlet of said heat exchanger, and said multipurpose valve having a combustion air inlet port fluidly connected to said air outlet of said heat exchanger.
- 4. The internal combustion engine of claim 3, including:a primary exhaust manifold in communication with at least a portion of said plurality of combustion cylinders, said primary exhaust manifold having a primary exhaust outlet port and a fluid inlet port; and said multipurpose valve having a fluid outlet port fluidly connected to said fluid inlet port of said primary exhaust manifold.
- 5. The internal combustion engine of claim 4, said multifunction valve being structured and arranged to be operable among a plurality of positions corresponding to a plurality of internal configurations.
- 6. The internal combustion engine of claim 4, said multifunction valve being structured and arranged to be operable in a first position corresponding to a first internal configuration such that said first valve inlet port is fluidly connected to said fluid outlet port.
- 7. The internal combustion engine of claim 4, said multifunction valve being structured and arranged to be operable in a second position corresponding to a second internal configuration such that said first valve inlet port is fluidly connected to said fluid outlet port and to said waste gas outlet port.
- 8. The internal combustion engine of claim 4, said multifunction valve being structured and arranged to be operable in a third position corresponding to a third internal configuration such that said first valve inlet port is fluidly connected to said first EGR outlet port.
- 9. The internal combustion engine of claim 4, said multifunction valve being structured and arranged to be operable in a fourth position corresponding to a fourth internal configuration such that said first valve inlet port is fluidly connected to said second EGR outlet port, and said combustion air inlet port is fluidly connected to said fluid outlet port.
- 10. The internal combustion engine of claim 4, said multifunction valve being structured and arranged to be operable in a fifth position corresponding to a fifth internal configuration such that said first valve inlet port is fluidly connected to said second EGR outlet port, and said combustion air inlet port is fluidly connected to said fluid outlet port and to said waste gas port.
- 11. The internal combustion engine of claim 4, including a turbocharger having a turbine and a compressor, said turbine having an exhaust gas inlet fluidly connected to said primary exhaust outlet port, and having an exhaust gas outlet, and said compressor having a compressor inlet and a compressor outlet, said compressor outlet being fluidly connected to said air intake port of said intake manifold.
- 12. The internal combustion engine of claim 1, including:a heat exchanger having an air inlet and an air outlet; said intake manifold having an air outlet port fluidly connected with said air inlet of said heat exchanger; and said multipurpose valve having a combustion air inlet port fluidly connected to said air outlet of said heat exchanger.
- 13. The internal combustion engine of claim 12, including:a primary exhaust manifold in communication with at least a portion of said plurality of combustion cylinders, said primary exhaust manifold having a primary exhaust outlet and a fluid inlet port; and said multipurpose valve having a fluid outlet port fluidly connected to said fluid inlet port of said primary exhaust manifold.
- 14. The internal combustion engine of claim 1, said multifunction valve including a selector shaft, said internal combustion engine including:an EGR controller; and an actuator electrically connected to said EGR controller, and mechanically connected to said selector shaft to operate said multifunction valve to a plurality of positions.
- 15. The internal combustion engine of claim 14, including a sensor assembly electrically coupled to said EGR controller, and adapted to monitor a status of at least one of a CO2 content of said exhaust gas, an NOx content of said exhaust gas, an EGR rate, an engine speed, and an altitude.
- 16. The internal combustion engine of claim 1, said multifunction valve including a valve body having a plurality of cavities, a valve cap defining an exhaust gas pocket, and a rotor having a first surface, a second surface, a selection port and an air pocket defined by said first surface, said first surface being positioned to face said valve body and said second surface being positioned to face said exhaust gas pocket of said valve cap.
- 17. A multifunction valve for adjusting EGR in an internal combustion engine, comprising:a valve body having a plurality of engine exhaust gas cavities, a waste exhaust cavity, and a hot combustion air cavity; a valve cap defining an engine exhaust gas pocket; and a rotor having a first surface, a second surface, a selection port extending through said rotor from said first surface to said second surface and an air pocket defined by said first surface, said first surface being positioned to face said valve body, with said air pocket opening toward said valve body, and said second surface being positioned to face said exhaust gas pocket of said valve cap, said selection port and said air pocket adapted and arranged for establishing flow communication between and among said cavities and said exhaust gas pocket for providing selected EGR gas flow through the valve.
- 18. The multifunction valve of claim 17, said rotor being structured and arranged to be operable among a plurality of positions.
- 19. The multifunction valve of claim 17, including a first valve inlet port, a second valve inlet port, a first valve outlet port, a second valve outlet port, a third valve outlet port and a fourth valve outlet port.
- 20. The multifunction valve of claim 19, said rotor being structured and arranged to be operable in a first position, a second position, a third position, a fourth position and a fifth position, said first position corresponding to a first internal configuration such that said first valve inlet port is fluidly connected to said first valve outlet port, said second position corresponding to a second internal configuration such that said first valve inlet port is fluidly connected to said first valve outlet port and to said second valve outlet port, said third position corresponding to a third internal configuration such that said first inlet port is fluidly connected to said third valve outlet port, said fourth position corresponding to a fourth internal configuration such that said first valve inlet port is fluidly connected to said fourth valve outlet port and said second valve inlet port is fluidly connected to said first valve outlet port, and said fifth position corresponding to a fifth internal configuration such that said first valve inlet port is fluidly connected to said fourth valve outlet port, and said second valve inlet port is fluidly connected to said first valve outlet port and to said second valve outlet port.
- 21. A method of operating a multifunction valve in an EGR system for an internal combustion engine which generates exhaust gases, comprising the steps of:operating said multifunction valve.in a first position to supply exhaust gas from a second exhaust manifold to a first exhaust manifold; and operating said multifunction valve in a second position to supply a portion of said exhaust gas from said second exhaust manifold to said first exhaust manifold and to at least partially open a waste port to waste a portion of said exhaust gases.
- 22. The method of claim 21, including the step of operating said multifunction valve in a third position to supply non-cooled exhaust gas to an intake manifold of said internal combustion engine.
- 23. The method of claim 21, including the step of operating said multifunction valve in a fourth position to supply cooled exhaust gas to an intake manifold of said internal combustion engine and to supply air received from said intake manifold to said first exhaust manifold.
- 24. The method of claim 21, including the step of operating said multifunction valve in a fifth position to supply cooled exhaust gas to an intake manifold of said internal combustion engine, to supply air received from said intake manifold to said first exhaust manifold and to at least partially open a waste port to waste a portion of said exhaust gases.
- 25. The method of claim 21 including the step of operating said multifunction valve using a single computer controlled actuator.
US Referenced Citations (14)