U.S. patent application number 13/472175 was filed with the patent office on 2012-09-06 for turbocharger having balance valve, wastegate, and common actuator.
This patent application is currently assigned to Caterpillar Inc.. Invention is credited to Craig Phillip Hittle, Jonathan P. Kilkenny, David Andrew Pierpont, Stephan Donald Roozenboom.
Application Number | 20120222419 13/472175 |
Document ID | / |
Family ID | 41606892 |
Filed Date | 2012-09-06 |
United States Patent
Application |
20120222419 |
Kind Code |
A1 |
Hittle; Craig Phillip ; et
al. |
September 6, 2012 |
TURBOCHARGER HAVING BALANCE VALVE, WASTEGATE, AND COMMON
ACTUATOR
Abstract
A turbocharger for a use with a combustion engine is provided.
The turbocharger may have a turbine housing with a first volute, a
second volute, and a common outlet. The turbocharger may also have
a turbine wheel disposed between the common outlet and the first
and second volutes. The turbocharger may further have a first valve
configured to selectively fluidly communicate the first volute with
the second volute upstream of the turbine wheel, a second valve
configured to selectively fluidly communicate the second volute
with the common outlet to bypass the turbine wheel, and a common
actuator configured to move the first and second valves.
Inventors: |
Hittle; Craig Phillip;
(Peoria, IL) ; Kilkenny; Jonathan P.; (Peoria,
IL) ; Pierpont; David Andrew; (Dunlap, IL) ;
Roozenboom; Stephan Donald; (Washington, IL) |
Assignee: |
Caterpillar Inc.
|
Family ID: |
41606892 |
Appl. No.: |
13/472175 |
Filed: |
May 15, 2012 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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12222009 |
Jul 31, 2008 |
8196403 |
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13472175 |
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Current U.S.
Class: |
60/605.1 ;
415/145 |
Current CPC
Class: |
Y02T 10/144 20130101;
F02M 26/22 20160201; F02B 37/183 20130101; F02B 37/025 20130101;
F02M 26/47 20160201 |
Class at
Publication: |
60/605.1 ;
415/145 |
International
Class: |
F02B 33/40 20060101
F02B033/40; F01D 17/10 20060101 F01D017/10 |
Claims
1. A turbocharger, comprising: a turbine housing having a first
volute, a second volute, and a common outlet; a turbine wheel
disposed between the common outlet and the first and second
volutes; a first valve configured to selectively fluidly
communicate the first volute with the second volute upstream of the
turbine wheel; a second valve configured to selectively fluidly
communicate the second volute with the common outlet to bypass the
turbine wheel; a common actuator configured to move the first and
second valves; and a first wall fluidly separating the first volute
from the second volute, the first wall having a first port, the
first valve being configured to selectively block the first
port.
2. The turbocharger of claim 1, wherein the first and second valves
are configured to rotate, and the common actuator is configured to
move linearly.
3. The turbocharger of claim 2, wherein the common actuator is
configured to move in a first direction by a first amount to rotate
only the first valve, and the common actuator is configured to move
in the first direction by a second amount to rotate both the first
valve and the second valve.
4. The turbocharger of claim 1, wherein the common actuator is
pneumatically operated.
5. The turbocharger of claim 1, further including a valve housing
connected to the turbine housing to at least partially enclose the
first and second valves, the valve housing including the first
wall.
6. (canceled)
7. The turbocharger of claim 1, wherein the common actuator is
fixedly connected to only the first valve.
8. The turbocharger of claim 7, further including: a first pivot
member fixedly connecting the common actuator to the first valve; a
second pivot member fixedly connected to only the second valve; and
a link member fixedly connected to the first pivot member and
including a channel configured to slidingly receive the second
pivot member.
9. (canceled)
10. The turbocharger of claim 1, wherein the common actuator is
configured to move to permit the first valve to fluidly communicate
the first volute with the second volute before the second valve
fluidly communicates the second volute with the common outlet.
11. The turbocharger of claim 1, wherein the first valve includes a
first pivot axis, and the second valve includes a second pivot axis
offset from the first pivot axis.
12. (canceled)
13. (canceled)
14. The turbocharger of claim 1, further including: a second wall
fluidly separating the second volute from the common outlet, the
second wall having a second port, wherein: the second valve is
configured to selectively block the second port.
15.-17. (canceled)
18. A method of handling exhaust from an engine having a first
plurality of combustion chambers and a second plurality of
combustion chambers, the method comprising: receiving exhaust from
the first plurality of combustion chambers; receiving exhaust from
the second plurality of combustion chambers; directing exhaust
received from the first and second pluralities of combustion
chambers through a turbine, the turbine including a housing having
a first volute and a second volute; moving a common actuator in a
first direction by a first amount to actuate a first valve of a
valve assembly to open a first port, thereby mixing exhaust
received from the first plurality of combustion chambers with
exhaust received from the second plurality of combustion chambers,
the first port being provided in a first wall fluidly separating
the first volute from the second volute; and moving the common
actuator in the first direction by a second amount to actuate a
second valve of the valve assembly to open a second port, thereby
allowing exhaust received from the second plurality of combustion
chambers to bypass the turbine, the second port being provided in a
second wall fluidly separating the second volute from a common
outlet of the turbine.
19. The method of claim 18, further including converting linear
motion from a common actuator to rotation of the valve
assembly.
20. A power system, comprising: an engine having a first plurality
of combustion chambers and a second plurality of combustion
chambers; a first exhaust manifold configured to receive exhaust
from only the first plurality of combustion chambers; a second
exhaust manifold configured to receive exhaust from only the second
plurality of combustion chambers; a turbocharger having: a turbine
housing, the turbine housing including a first volute in fluid
communication with the first exhaust manifold, a second volute
having a greater flow capacity than the first volute and being in
fluid communication with the second exhaust manifold, and a common
outlet, and a turbine wheel configured to receive exhaust from the
first and second volutes; a valve assembly including: a first valve
configured to selectively fluidly communicate the first volute with
the second volute at a location upstream of the turbine wheel, and
a second valve configured to selectively fluidly communicate the
second volute with the common outlet to bypass the turbine wheel; a
single actuator configured to move the valve assembly; and a valve
housing connected to the turbine housing and at least partially
enclosing the first and second valves, the valve housing including:
a first wall member separating a first compartment fluidly
communicating with the first volute from a second compartment
fluidly communicating with the second volute, and a second wall
member separating the second compartment from the common outlet,
the first valve being provided in the first compartment between the
first and second walls.
21. The power system of claim 20, wherein the first valve includes
a first pivot axis, and the second valve includes a second pivot
axis offset from the first pivot axis.
22. The power system of claim 20, wherein the first and second wall
members are substantially parallel.
23. The power system of claim 20, wherein the first valve is
disposed between the first and second wall members.
24. The method of claim 18, wherein, prior to moving the common
actuator in the first direction, the first valve closes the first
port and the second valve closes the second port.
25. The method of claim 18, wherein the second amount of movement
of the common actuator is greater than the first amount of movement
of the common actuator.
26. The turbocharger of claim 14, further including a valve housing
connected to the turbine housing to at least partially enclose the
first and second valves, the valve housing including the first wall
and the second wall.
Description
TECHNICAL FIELD
[0001] The present disclosure is directed to a turbocharger and,
more particularly, to a turbocharger having a balance valve, a
wastegate, and an actuator common to both the balance valve and the
wastegate valve.
BACKGROUND
[0002] Combustion engines such as diesel engines, gasoline engines,
and gaseous fuel-powered engines are supplied with a mixture of air
and fuel for combustion within the engine that generates a
mechanical power output. In order to maximize the power output
generated by this combustion process, the engine is often equipped
with a divided exhaust manifold in fluid communication with a
turbocharged air induction system.
[0003] The divided exhaust manifold increases engine power by
helping to preserve exhaust pulse energy generated by the engine's
combustion chambers. Preserving the exhaust pulse energy improves
turbocharger operation, which results in a more efficient use of
fuel. In addition, the turbocharged air induction system increases
engine power by forcing more air into the combustion chambers than
would otherwise be possible. This increased amount of air allows
for enhanced fueling that further increases the power output
generated by the engine.
[0004] In addition to the goal of maximizing engine power output
and efficiency, it is desirable to simultaneously minimize exhaust
emissions. That is, combustion engines exhaust a complex mixture of
air pollutants as byproducts of the combustion process. And, due to
increased attention on the environment, exhaust emission standards
have become more stringent. The amount of pollutants emitted to the
atmosphere from an engine can be regulated depending on the type of
engine, size of engine, and/or class of engine.
[0005] One method that has been implemented by engine manufacturers
to comply with the regulation of these exhaust emissions includes
utilizing an exhaust gas recirculating (EGR) system. EGR systems
operate by recirculating a portion of the exhaust produced by the
engine back to the intake of the engine to mix with fresh
combustion air. The resulting mixture has a lower combustion
temperature and, subsequently, produces a reduced amount of
regulated pollutants.
[0006] EGR systems require a certain level of backpressure in the
exhaust system to push a desired amount of exhaust back to the
intake of the engine. And, the backpressure needed for adequate
operation of the EGR system varies with engine load. Although
effective, utilizing exhaust backpressure to drive EGR can
adversely affect engine operation, thereby reducing fuel economy.
Thus, a system is required to reduce exhaust back pressure while
still providing the necessary EGR flow.
[0007] U.S. Pat. No. 6,321,537 to Coleman et al. ("the '537
patent") discloses a combustion engine utilizing an EGR system and
a divided exhaust manifold together with a turbocharged air
induction system. Specifically, the '537 patent describes an
internal combustion engine having a plurality of combustion
cylinders and an intake manifold in common fluid communication with
the combustion cylinders. A first exhaust manifold and a second
exhaust manifold are separately coupled with the combustion
cylinders. A first variable geometry turbine is associated with the
first exhaust manifold, and a second variable geometry turbine is
associated with the second exhaust manifold. The EGR system
includes a 3-way valve assembly disposed in fluid communication
between the first exhaust manifold, the second exhaust manifold,
and the intake manifold. The valve assembly includes an inlet
fluidly coupled with an inlet of the first variable geometry
turbine, a first outlet fluidly coupled with an inlet of the second
variable geometry turbine, and a second outlet fluidly coupled with
the intake manifold.
[0008] During operation of the combustion engine described in the
'537 patent, exhaust flows in parallel from the first exhaust
manifold to the first variable geometry turbine and from the first
exhaust manifold to the valve assembly. Spent exhaust from the
first variable geometry turbine is mixed with exhaust from the
second exhaust manifold and fed to the second variable geometry
turbine. Spent exhaust from the second variable geometry turbine is
discharged to the ambient environment. The valve assembly is
selectively actuated to control a flow of exhaust from the two
outlets. Exhaust flowing from the first outlet mixes with exhaust
from the second exhaust manifold and flows into the second variable
geometry turbine. Exhaust from the second outlet is cooled and then
mixed with combustion air. The mixture of combustion air and
exhaust is then transported to the inlet manifold. Controlling the
amount of exhaust gas which is transported to the intake manifold
provides effective exhaust gas recirculation within the combustion
engine. Moreover, controlling the flow of exhaust to the second
variable geometry turbine utilizes energy from the exhaust which is
not transported to the intake manifold to drive the second variable
geometry turbine.
[0009] Although the system in the '537 patent may adequately
control exhaust gas recirculation in a turbocharged engine, it may
be less than optimal. That is, in some situations, the backpressure
within the first exhaust manifold may be excessive. And, without
any way to relieve this backpressure, damage to the first variable
geometry turbocharger may be possible.
[0010] The disclosed turbocharger is directed to overcoming one or
more of the problems set forth above and/or other problems of the
prior art.
SUMMARY
[0011] In one aspect, the disclosure is directed toward a
turbocharger. The turbocharger may include a turbine housing with a
first volute, a second volute, and a common outlet. The
turbocharger may also include a turbine wheel disposed between the
common outlet and the first and second volutes. The turbocharger
may further include a first valve configured to selectively fluidly
communicate the first volute with the second volute upstream of the
turbine wheel, a second valve configured to selectively fluidly
communicate the second volute with the common outlet to bypass the
turbine wheel, and a common actuator configured to move the first
and second valves.
[0012] In another aspect, the disclosure is directed toward a
method of handling exhaust from an engine having a first plurality
of combustion chambers and a second plurality of combustion
chambers. The method may include receiving exhaust from the first
plurality of combustion chambers, and receiving exhaust from the
second plurality of combustion chambers. The method may also
include moving a valve assembly in a first direction by a first
amount to mix exhaust received from the first plurality of
combustion chambers with exhaust received from the second plurality
of combustion chambers, directing exhaust received from the first
and second pluralities of combustion chambers through a turbine,
and moving the valve assembly in the first direction by a second
amount to allow exhaust received from the second plurality of
combustion chambers to bypass the turbine.
[0013] In yet another aspect, the disclosure is directed toward a
power system. The power system may include an engine having a first
plurality of combustion chambers and a second plurality of
combustion chambers. The power system may also include a first
exhaust manifold configured to receive exhaust from only the first
plurality of combustion chambers, a second exhaust manifold
configured to receive exhaust from only the second plurality of
combustion chambers, and a turbocharger. The turbocharger may have
a first volute in fluid communication with the first exhaust
manifold, a second volute having a greater flow capacity than the
first volute and being in fluid communication with the second
exhaust manifold, a turbine wheel configured to receive exhaust
from the first and second volutes, and a common outlet. The power
system may further include a valve assembly configured to
selectively fluidly communicate the first volute with the second
volute at a location upstream of the turbine wheel, and to
selectively fluidly communicate the second volute with the common
outlet to bypass the turbine wheel and a single actuator configured
to move the valve assembly.
BRIEF DESCRIPTION OF THE DRAWINGS
[0014] FIG. 1 is a diagrammatic illustration of an exemplary
disclosed power system;
[0015] FIG. 2 is a pictorial illustration of an exemplary disclosed
turbocharger that may be used with the power system of FIG. 1;
[0016] FIG. 3 is a pictorial illustration of a portion of the
turbocharger shown in FIG. 2;
[0017] FIG. 4 is a pictorial illustration of a portion of the
turbocharger shown in FIG. 2;
[0018] FIG. 5 is a pictorial illustration of another exemplary
disclosed power system;
[0019] FIG. 6 is a pictorial illustration of an exemplary disclosed
turbocharger that may be used with the power system of FIG. 5;
[0020] FIG. 7 is a pictorial illustration of a portion of the
turbocharger shown in FIG. 6; and
[0021] FIG. 8 is a pictorial illustration of a portion of the
turbocharger shown in FIG. 6.
DETAILED DESCRIPTION
[0022] FIG. 1 illustrates a power system 10 having a power source
12, an air induction system 14, and an exhaust system 16. For the
purposes of this disclosure, power source 12 is depicted and
described as a four-stroke diesel engine. One skilled in the art
will recognize, however, that power source 12 may be any other type
of combustion engine such as, for example, a gasoline or a gaseous
fuel-powered engine. Power source 12 may include an engine block 18
that at least partially defines a plurality of cylinders 20. A
piston (not shown) may be slidably disposed within each cylinder 20
to reciprocate between a top-dead-center position and a
bottom-dead-center position, and a cylinder head (not shown) may be
associated with each cylinder 20. Cylinder 20, the piston, and the
cylinder head may form a combustion chamber 22. In the illustrated
embodiment, power source 12 includes six such combustion chambers
22. However, it is contemplated that power source 12 may include a
greater or lesser number of combustion chambers 22 and that
combustion chambers 22 may be disposed in an "in-line"
configuration, a "V" configuration, or in any other suitable
configuration.
[0023] Air induction system 14 may include components configured to
introduce charged air into power source 12. For example, air
induction system 14 may include an induction valve 24, one or more
compressors 26, and an air cooler 28. Induction valve 24 may be
connected upstream of compressor 26 via a fluid passageway 30 and
configured to regulate a flow of atmospheric air to power source
12. Compressor 26 may embody a fixed geometry compressor configured
to receive air from induction valve 24 and compress the air to a
predetermined pressure level before it enters power source 12.
Compressor 26 may be connected to power source 12 via a fluid
passageway 32. Air cooler 28 may be disposed within fluid
passageway 32, between power source 12 and compressor 26 and
embody, for example, an air-to-air heat exchanger, an air-to-liquid
heat exchanger, or a combination of both to facilitate the transfer
of thermal energy to or from the compressed air directed into power
source 12.
[0024] Exhaust system 16 may include components configured to
direct exhaust from power source 12 to the atmosphere.
Specifically, exhaust system 16 may include first and second
exhaust manifolds 34 and 36 in fluid communication with combustion
chambers 22, an exhaust gas recirculation (EGR) circuit 38 fluidly
communicating first exhaust manifold 34 with air induction system
14, a turbine 40 associated with first and second exhaust manifolds
34, 36, and a control system 44 for regulating exhaust flows from
exhaust system 16 to air induction system 14. It is contemplated
that exhaust system 16 may include components in addition to those
listed above such as, for example, particulate removing devices,
constituent absorbers or reducers, and attenuation devices, if
desired.
[0025] Exhaust produced during the combustion process within
combustion chambers 22 may exit power source 12 via either first
exhaust manifold 34 or second exhaust manifold 36. First exhaust
manifold 34 may fluidly connect a first plurality of combustion
chambers 22 of power source 12 (e.g., the first three combustion
chambers 22 from the right shown in FIG. 1) to turbine 40. Second
exhaust manifold 36 may fluidly connect a second plurality of
combustion chambers 22 of power source 12 (e.g., the final three
combustion chambers from the right shown in FIG. 1) to turbine
40.
[0026] EGR circuit 38 may include components that cooperate to
redirect a portion of the exhaust produced by power source 12 from
first exhaust manifold 34 to air induction system 14. Specifically,
EGR circuit 38 may include an inlet port 52, an EGR cooler 54, a
recirculation control valve 56, and a discharge port 58. Inlet port
52 may be fluidly connected to first exhaust manifold 34 upstream
of turbine 40 and fluidly connected to EGR cooler 54 via a fluid
passageway 60. Discharge port 58 may receive exhaust from EGR
cooler 54 via a fluid passageway 62, and discharge the exhaust to
air induction system 14 at a location downstream of air cooler 28.
Recirculation control valve 56 may be disposed within fluid
passageway 62, between EGR cooler 54 and discharge port 58. It is
contemplated that a check valve, for example a reed-type check
valve 50 may be situated within fluid passageway 62 upstream or
downstream of recirculation control valve 56 at a location where
exhaust mixes with inlet air to provide for a unidirectional flow
of exhaust through EGR circuit 38 (i.e., to inhibit bidirectional
exhaust flows through EGR circuit 38), if desired.
[0027] Recirculation control valve 56 may be located to control the
flow of exhaust recirculated through EGR circuit 38. Recirculation
control valve 56 may be any type of valve known in the art such as,
for example, a butterfly valve, a diaphragm valve, a gate valve, a
ball valve, a poppet valve, or a globe valve. In addition,
recirculation control valve 56 may be solenoid-actuated,
hydraulically-actuated, pneumatically-actuated or actuated in any
other manner to selectively restrict or completely block the flow
of exhaust through fluid passageways 60 and 62.
[0028] EGR cooler 54 may be configured to cool exhaust flowing
through EGR circuit 38 and, subsequently, components within EGR
circuit 38 (e.g., recirculation control valve 56). EGR cooler 54
may include a liquid-to-air heat exchanger, an air-to-air heat
exchanger, or any other type of heat exchanger known in the art for
cooling an exhaust flow.
[0029] Turbine 40 may be a fixed geometry turbine configured to
drive compressor 26. For example, turbine 40 may be directly and
mechanically connected to compressor 26 by way of a shaft 64 to
form a fixed geometry turbocharger 66. As the hot exhaust gases
exiting power source 12 move through turbine 40 and expand against
blades (not shown) therein, turbine 40 may rotate and drive the
connected compressor 26 to pressurize inlet air.
[0030] Turbine 40 may include a divided housing having a first
volute 76 with a first inlet 78 fluidly connected with first
exhaust manifold 34, and a second volute 80 with a second inlet 82
fluidly connected with second exhaust manifold 36 (i.e.,
turbocharger 66 may have dual volutes). A wall member 84 may divide
first volute 76 from second volute 80. It should be understood that
at least a part of first volute 76 and/or first inlet 78 may have a
smaller cross-sectional area and/or area/radius (A/R) ratio than
second volute 80 and/or second inlet 82. The smaller
cross-sectional area or A/R ratio may help restrict the flow of
exhaust through first exhaust manifold 34, thereby creating
backpressure sufficient to push at least a portion of the exhaust
from first exhaust manifold 34 through EGR circuit 38.
[0031] A valve assembly 86 may be associated with turbine 40 to
regulate a pressure of exhaust within EGR circuit 38. Valve
assembly 86 may include, among other things, a balance valve 88, a
wastegate valve 90, and a common actuator 92. Balance valve 88 may
be configured to selectively allow exhaust from first volute 76 to
pass to second volute 80. Wastegate valve 90 may be configured to
selectively allow exhaust from second volute 80 to bypass a turbine
wheel 93 of turbine 40. Common actuator 92 may be controlled to
move both balance valve 88 and wastegate valve 90 between flow
passing and flow blocking positions. Valve assembly 86 may be
integral with turbine 40 and at least partially enclosed by a valve
housing 94 that mounts to a turbine housing 96 of turbine 40.
[0032] Balance valve 88 may be configured to regulate a pressure of
exhaust within first exhaust manifold 34 by selectively allowing
exhaust to flow from first volute 76 to second volute 80. It should
be understood that the pressure within first exhaust manifold 34
may affect the amount of exhaust pushed through EGR circuit 38.
That is, when exhaust flows from first volute 76 to second volute
80 by way of balance valve 88, a pressure within first exhaust
manifold 34 may be reduced and, as a result of this reduction, an
amount of exhaust forced from first exhaust manifold 34 through EGR
circuit 38 may be reduced by a proportional amount. It should also
be noted that, because exhaust may selectively be allowed to flow
from first volute 76 to second volute 80 by way of balance valve
88, a pressure differential between first and second volutes 76 and
80 may be minimized, thereby minimizing an impact this pressure
differential may have on turbocharger efficiency.
[0033] As shown in FIG. 2, balance valve 88 may be fixedly
connected to common actuator 92. Specifically, balance valve 88 may
include a valve member 98 having a pivot axis 100. A pivot member
102 may be fixedly connected at a center thereof to valve member
98, and at an end thereof to common actuator 92. In this
configuration, as common actuator 92 moves linearly in the
direction of an arrow 104, pivot member 102 and connected valve
member 98 may both be caused to rotate together about pivot axis
100.
[0034] As illustrated in FIGS. 3 and 4, valve housing 94 may at
least partially define a fluid chamber 106 divided into two
compartments 106a and 106b by a wall member 108. Compartment 106a
may fluidly communicate with first volute 76, while compartment
106b may fluidly communicate with second volute 80. A port 110
within wall member 108 may fluidly connect compartments 106a and
106b, and a sealing element 111 of valve member 98 may selectively
pivot about pivot axis 100 to open or close port 110 and thereby
selectively restrict a flow of exhaust from first volute 76 to
second volute 80 by way of port 110.
[0035] Referring back to FIG. 2, wastegate valve 90 may be
connected to balance valve 88 and to common actuator 92 by way of a
link member 112. In particular, a pivot member 114 may be connected
at one end thereof to a valve member 115 of wastegate valve 90, and
include a protrusion 114a at an opposing end thereof. Link member
112 may be fixedly connected to an end of pivot member 102,
opposite the connection of pivot member 102 to common actuator 92,
and include a channel 112a configured to slidingly receive
protrusion 114a of pivot member 114. In this configuration, as
balance valve 88 and pivot member 102 are rotated about pivot axis
100 by linear movement of common actuator 92, link member 112 may
also move linearly in a direction substantially opposite the
movement of common actuator 92. And, as link member 112 moves
linearly, protrusion 114a may be caused to slide within channel
112a of link member 112 until an end of channel 112a is engaged.
Once the end of channel 112a is engaged by protrusion 114a, pivot
member 114 and connected valve member 115 may then be rotated about
an axis 116 together with pivot member 102 and connected valve
member 98 about pivot axis 100 by further movement of common
actuator 92 in the same direction. When common actuator 92 moves in
a reverse direction, balance valve 88 may again move first (i.e.,
before movement of wastegate valve 90 is initiated) until an
opposing end of channel 112a is engaged by protrusion 114a.
[0036] Referring again to FIGS. 3 and 4, fluid chamber 106 may be
separated from a common outlet 118 of turbine 40 by a wall member
120. A port 122 within wall member 120 may connect fluid chamber
106 with common outlet 118, and a sealing element 124 of valve
member 115 may selectively pivot about axis 116 to open or close
port 122 and thereby restrict a flow of exhaust from second volute
80 to outlet 118 (i.e., sealing element 124 may selectively allow
or restrict exhaust within second volute 80 from bypassing turbine
wheel 93 of turbine 40).
[0037] Referring again to FIG. 2, common actuator 92 may be
pneumatically operated to initiate movement of balance valve 88 and
wastegate valve 90. Specifically, common actuator 92 may include a
spring-biased piston member (not shown) disposed within a pressure
chamber 92a and fixedly connected to a piston rod 92b. Pressurized
air directed into pressure chamber 92a may urge the spring-biased
piston member from a first position away from pressure chamber 92a
toward a second position. Conversely, allowing the pressurized air
to drain from pressure chamber 92a may return the spring-biased
piston member to the first position. As piston rod 92b translates
between the first and second positions, balance valve 88 may first
move, followed by movement of wastegate valve 90. It is
contemplated that common actuator 92 may alternatively be
mechanically operated, hydraulically operated, electrically
operated, or operated in any other suitable manner. It is also
contemplated that piston rod 92b may be moved to any position
between the first and second positions to thereby provide more than
two levels of actuation, if desired (i.e., common actuator 92 may
be a proportional actuator, wherein a movement amount of piston rod
92b is directly proportional to a pressure of the air directed into
pressure chamber 92a).
[0038] Referring back to FIG. 1, control system 44 may include
components that function to regulate the flow rate and pressure of
exhaust passing though first volute 76, second volute 80, and EGR
circuit 38 by adjusting the position of recirculation control valve
56, balance valve 88, and/or wastegate valve 90 in response to
sensory input. Specifically, control system 44 may include a sensor
46, and a controller 48 in communication with sensor 46,
recirculation control valve 56, and common actuator 92. Based on
signals received from sensor 46, controller 48 may adjust a
position of recirculation control valve 56 and/or of common
actuator 92 to vary the restrictions provided by recirculation
control valve 56, balance valve 88, and/or wastegate valve 90.
[0039] Although shown as located downstream of EGR cooler 54 and
upstream of recirculation control valve 56, sensor 46 may
alternatively be located anywhere within EGR circuit 38 and embody,
for example, a mass air flow sensor such as a hot wire anemometer
or a venturi-type sensor configured to sense pressure and/or a flow
rate of exhaust passing through EGR circuit 38. Controller 48 may
use signals produced by sensor 46 to determine and/or adjust a
backpressure within first exhaust manifold 34 such that a desired
amount of exhaust is recirculated back into power source 12 for
subsequent combustion. This adjustment of pressure will be further
explained in more detail below.
[0040] Controller 48 may embody a single or multiple
microprocessors, field programmable gate arrays (FPGAs), digital
signal processors (DSPs), etc. that include a means for controlling
an operation of power system 10 in response to signals received
from sensor 46. Numerous commercially available microprocessors can
be configured to perform the functions of controller 48. It should
be appreciated that controller 48 could readily embody a
microprocessor separate from that controlling other non-exhaust
related power system functions, or that controller 48 could be
integral with a general power system microprocessor and be capable
of controlling numerous power system functions and modes of
operation. If separate from a general power system microprocessor,
controller 48 may communicate with the general power system
microprocessor via data links or other methods. Various other known
circuits may be associated with controller 48, including power
supply circuitry, signal-conditioning circuitry, actuator driver
circuitry (i.e., circuitry powering solenoids, motors, or piezo
actuators), communication circuitry, and other appropriate
circuitry.
[0041] Before regulating the flow of exhaust through EGR circuit
38, controller 48 may first receive data indicative of an
operational condition of power source 12 or a desired exhaust flow
rate and/or pressure. Such data may be received from another
controller or computer (not shown). In an alternative embodiment,
operational condition data may be received from sensors
strategically located throughout power system 10. Controller 48 may
then utilize stored algorithms, equations, subroutines, look-up
maps, and/or tables to analyze the operational condition data and
determine a corresponding desired exhaust pressure and/or flow rate
through EGR circuit 38.
[0042] Controller 48 may also receive signals from sensor 46
indicative of the flow rate or pressure of exhaust flowing through
first exhaust manifold 34. Upon receiving input signals from sensor
46, controller 48 may perform a plurality of operations utilizing
stored algorithms, equations, subroutines, look-up maps and/or
tables to determine whether the flow rate or pressure of exhaust
flowing through first exhaust manifold 34 is within a desired range
for producing the desired exhaust flow rate through EGR circuit 38.
In an alternate embodiment, it is contemplated that controller 48
may receive signals from various sensors (not shown) located
throughout exhaust system 16 and/or power system 10 instead of
sensor 46. Such sensors may sense parameters that may be used to
calculate the flow rate or pressure of exhaust flowing through
first exhaust manifold 34, if desired.
[0043] Based on the comparison of the actual EGR flow rate and/or
pressure with the desired range of flow rates and/or pressures,
controller 48 may adjust operation of exhaust system 16. That is,
controller 48 may adjust operation of recirculation control valve
56, of balance valve 88, and/or of wastegate valve 90 to affect the
pressure within first exhaust manifold 34 and the resulting flow
rates of exhaust through EGR circuit 38, first volute 76, and
second volute 80. To increase the flow rate and pressure of exhaust
passing through first volute 76 and EGR circuit 38, and to
simultaneously decrease the flow rates and pressures of exhaust
passing through second volute 80, balance valve 88 may be closed to
a greater extent. To decrease the flow rate and pressure of exhaust
passing through first volute 76 and EGR circuit 38, and to
simultaneously increase the flow rates and pressures of exhaust
passing through second volute 80, balance valve 88 may be opened.
Recirculation control valve 56 may be opened to increase an EGR
flow rate and decrease exhaust flow through first volute 76, and
closed to decrease an EGR flow rate and increase exhaust flow
through first volute 76. In one embodiment, controller 48 may
primarily adjust operation of balance valve 88 to achieve a desired
flow rate and/or pressure of exhaust through EGR circuit 38. After
balance valve 88 has been adjusted to a maximum or minimum
position, controller 48 may then adjust operation of recirculation
control valve 56 and/or wastegate valve 90 to provide further EGR
modulation.
[0044] FIG. 5 illustrates an alternative embodiment of power system
10. Similar to the embodiment of FIG. 1, the embodiment of FIG. 5
includes power system 10 having power source 12, air induction
system 14, and exhaust system 16. However, in contrast to the
embodiment of FIG. 1, turbine 40 of exhaust system 16 may include a
different valve assembly 86. That is, valve assembly 86 of FIG. 5
may include a balance valve 126 and a wastegate valve 128 moved by
common actuator 92. Balance valve 126 may include two separate
valve members, and wastegate valve 128 may have a different
configuration than in the previous embodiments. In addition, the
linkage connecting balance valve 126 and wastegate valve 128 to
common actuator 92 may be different, as will be described in more
detail below.
[0045] Balance valve 126 and wastegate valve 128 may connect to and
be moved by common actuator 92 in a manner similar to the
embodiments of FIGS. 1-5. That is, as illustrated in FIG. 6,
balance valve 126 may be fixedly connected to common actuator 92 by
way of a pivot member 130 to rotate about a pivot axis 132.
Wastegate valve 128 may include a pivot member 134 having a channel
134a. And, as common actuator 92 begins to move linearly, only
pivot member 130 and connected balance valve 126 may move until a
protrusion 130a of pivot member 130 engages an end of channel 134a.
Once protrusion 130a engages the end of channel 134a, pivot member
134 and connected wastegate valve 128 may also be moved by the
linear motion of common actuator 92.
[0046] As shown in FIGS. 7 and 8, balance valve 126 may include a
first valve member 136 and a second valve member 138 rigidly
connected to each other and disposed at least partially within a
fluid chamber 140. Fluid chamber 140 may be at least partially
defined by turbine housing 96 (i.e., at least partially defined by
a wall member 141 of turbine housing 96) and fluidly communicate
with fluid chamber 106 of valve housing 94. No walls may separate
fluid chambers 140 or 106 into separate compartments in this
embodiment. First valve member 136 may be associated with first
volute 76, while second valve member 138 may be associated with
second volute 80. A first port 142 within wall member 141 may
communicate fluid chamber 140 with first volute 76, while a second
port 144 within wall member 141 may fluidly communicate fluid
chamber 140 with second volute 80. First and second valve members
136, 138 may include first and second sealing surfaces (not shown),
respectively, that are configured to selectively restrict fluid
flow through first and second ports 142, 144. Both of first and
second valve members 136, 138 may be connected to a rod member 146
to rotate together about pivot axis 132 when an input from common
actuator 92 is received.
[0047] In the embodiment of FIGS. 5-8, wastegate valve 128 may be
substantially axially aligned with balance valve 126 and include a
sleeve member 148 fixedly connected to pivot member 126 and
configured to at least partially receive rod member 146 of balance
valve 126. A valve member 150 of wastegate valve 128 may be rigidly
connected to rotate with sleeve member 148 and selectively restrict
exhaust flow through a port 152 to common outlet 118 of turbine
40.
INDUSTRIAL APPLICABILITY
[0048] The disclosed exhaust system may be implemented into any
power system application where charged air induction and exhaust
gas recirculation are utilized. The disclosed exhaust system may be
simple, have high durability, and offer control precision.
Specifically, the fixed geometry nature of turbocharger 66 may
decrease the complexity and cost of the disclosed exhaust system,
while recirculation control valve 56, balance valves 88 or 126, and
wastegate valves 90 or 128 may help to maintain precision and
controllability: In addition, the location of recirculation control
valve 56, sensor 46, and check valve 50 downstream of EGR cooler 54
may result in cooler operating temperatures of those components and
extended component lives. Further, the use of check valve 50 may
enhance turbocharger stability and efficiency. Finally, by
utilizing direct flow sensing and feedback control, precise
regulation of exhaust gas recirculation may be possible.
[0049] It will be apparent to those skilled in the art that various
modifications and variations can be made to the disclosed
turbocharger. Other embodiments will be apparent to those skilled
in the art from consideration of the specification and practice of
the disclosed turbocharger. It is intended that the specification
and examples be considered as exemplary only, with a true scope
being indicated by the following claims and their equivalents.
* * * * *