U.S. patent application number 09/850941 was filed with the patent office on 2002-11-14 for egr/bleed air diverter valve.
Invention is credited to Bailey, Brett M..
Application Number | 20020166547 09/850941 |
Document ID | / |
Family ID | 25309505 |
Filed Date | 2002-11-14 |
United States Patent
Application |
20020166547 |
Kind Code |
A1 |
Bailey, Brett M. |
November 14, 2002 |
EGR/BLEED AIR DIVERTER VALVE
Abstract
A valve for use in an EGR system for an internal combustion
engine has a housing having an exhaust inlet, an EGR outlet, an
exhaust outlet and a bleed air inlet. A butterfly plate is
pivotally connected to the housing. The butterfly plate has at
least a first position and a second position, wherein the first
position defines a first fluid path between the exhaust inlet and
the EGR outlet and defines a second fluid path between the bleed
air inlet and the exhaust outlet, and wherein the second position
defines a third fluid path between the exhaust inlet and the
exhaust outlet and defines a fourth fluid path between the bleed
air inlet and the EGR outlet.
Inventors: |
Bailey, Brett M.; (Peoria,
IL) |
Correspondence
Address: |
Taylor & Aust, P.C.
ATTN: Ronald K. Aust
12029 E. Washington Street
Indianapolis
IN
46229
US
|
Family ID: |
25309505 |
Appl. No.: |
09/850941 |
Filed: |
May 8, 2001 |
Current U.S.
Class: |
123/568.15 ;
60/605.2 |
Current CPC
Class: |
Y02T 10/144 20130101;
F02M 26/10 20160201; F02M 26/53 20160201; F02D 9/10 20130101; F02M
26/47 20160201; F02B 37/16 20130101; F02D 2009/0276 20130101; F02M
26/05 20160201; F02M 26/71 20160201; F02M 26/16 20160201; F02B
29/0406 20130101; F02M 26/43 20160201; F02B 33/44 20130101; Y02T
10/12 20130101 |
Class at
Publication: |
123/568.15 ;
60/605.2 |
International
Class: |
F02M 025/07 |
Claims
1. A valve for use in an EGR system for an internal combustion
engine, comprising: a housing, said housing having an exhaust
inlet, an EGR outlet, an exhaust outlet and a bleed air inlet; a
pivot shaft pivotally coupled to said housing; and a butterfly
plate connected to said pivot shaft, said butterfly plate having at
least a first position and a second position, wherein said first
position defines a first fluid path between said exhaust inlet and
said EGR outlet and defines a second fluid path between said bleed
air inlet and said exhaust outlet, and wherein said second position
defines a third fluid path between said exhaust inlet and said
exhaust outlet and defines a fourth fluid path between said bleed
air inlet and said EGR outlet.
2. The valve of claim 1, wherein said butterfly plate is variably
positionable between said first position and said second position
to simultaneously control an EGR gases fluid flow rate and a
compressed bleed air fluid flow rate.
3. The valve of claim 1, wherein said valve includes a first seal
stop, a second seal stop, a third seal stop and a fourth seal stop,
wherein when said butterfly plate is positioned in said first
position, said butterfly plate contacts said first seal stop and
said second seal stop, and does not contact said third seal stop
and said fourth seal stop, and when said butterfly plate is
positioned in said second position, said butterfly plate contacts
said third seal stop and said fourth seal stop, and does not
contact said first seal stop and said second seal stop.
4. The valve of claim 3, wherein each of said first seal stop, said
second seal stop, said third seal stop and said fourth seal stop is
made of metal.
5. The valve of claim 3, wherein each of said first seal stop, said
second seal stop, said third seal stop and said fourth seal stop
contacts a respective one of a first side surface and a second side
surface of said butterfly plate.
6. An internal combustion engine, comprising: a block defining a
plurality of combustion cylinders, said plurality of combustion
cylinders having a first group of combustion cylinders and at least
one EGR pumping cylinder; an intake manifold connected to said
block for providing combustion air to each of said plurality of
combustion cylinders; a first exhaust manifold connected to said
block to receive combustion gases from said first group of
combustion cylinders; a second exhaust manifold connected to said
block to receive combustion gases from said at least one EGR
pumping cylinder; a turbocharger having a turbine and a compressor,
said turbine having an exhaust gas inlet port and an exhaust gas
outlet port, said exhaust gas inlet port of said turbine being
coupled for fluid communication with at least one of said first
exhaust manifold and said second exhaust manifold, said compressor
having an air inlet port and a compressed air outlet port, said air
inlet port of said compressor being in fluid communication with the
atmosphere; a compressed air conduit coupled to provide fluid
communication between said compressed air outlet port and said
intake manifold, said compressed air conduit having a bleed air
port; a valve having a housing and a valve mechanism, said housing
having an exhaust inlet, an EGR outlet, an exhaust outlet and a
bleed air inlet, said exhaust inlet being connected in fluid
communication with said second exhaust manifold, said EGR outlet
being connected in fluid communication with said intake manifold,
said exhaust outlet being connected in fluid communication with
said first exhaust manifold and said turbine, and said bleed air
inlet being connected in fluid communication with said bleed air
port of said compressed air conduit, said valve mechanism having at
least a first position and a second position, wherein said first
position defines a first fluid path between said exhaust inlet and
said EGR outlet and defines a second fluid path between said bleed
air inlet and said exhaust outlet, and wherein said second position
defines a third fluid path between said exhaust inlet and said
exhaust outlet and defines a fourth fluid path between said bleed
air inlet and said EGR outlet.
7. The internal combustion engine of claim 6, wherein said valve
mechanism has a butterfly plate connected to a pivot shaft, said
pivot shaft being pivotally coupled to said housing.
8. The internal combustion engine of claim 7, wherein said
butterfly plate is variably positionable between said first
position and said second position to simultaneously control an
amount of EGR gases supplied to said intake manifold and an amount
of compressed bleed air supplied to said first exhaust
manifold.
9. The internal combustion engine of claim 7, wherein said valve
includes a first seal stop, a second seal stop, a third seal stop
and a fourth seal stop, wherein when said butterfly plate is
positioned in said first position, said butterfly plate contacts
said first seal stop and said second seal stop, and does not
contact said third seal stop and said fourth seal stop, and when
said butterfly plate is positioned in said second position, said
butterfly plate contacts said third seal stop and said fourth seal
stop, and does not contact said first seal stop and said second
seal stop.
10. The internal combustion engine of claim 9, wherein each of said
first seal stop, said second seal stop, said third seal stop and
said fourth seal stop is made of metal.
11. The internal combustion engine of claim 9, wherein each of said
first seal stop, said second seal stop, said third seal stop and
said fourth seal stop contacts a respective one of a first side
surface and a second side surface of said butterfly plate.
12. The internal combustion engine of claim 7, including a valve
controller coupled to said pivot shaft.
13. A method of providing EGR for an internal combustion engine,
comprising the steps of: providing a single valve having a housing
and a valve mechanism, said housing having an exhaust inlet, an EGR
outlet, an exhaust outlet and a bleed air inlet; positioning said
valve mechanism in a first position to define a first fluid path
between said exhaust inlet and said EGR outlet and to define a
second fluid path between said bleed air inlet and said exhaust
outlet; positioning said valve mechanism in a second position to
define a third fluid path between said exhaust inlet and said
exhaust outlet and to define a fourth fluid path between said bleed
air inlet and said EGR outlet; and positioning said valve mechanism
between said first position and said second position to
simultaneously control an amount of EGR gases supplied to an intake
manifold of said internal combustion engine and an amount of
compressed bleed air supplied to an exhaust manifold of said
internal combustion engine.
Description
TECHNICAL FIELD
[0001] This invention relates generally to an internal combustion
engine and, more particularly, to an EGR/bleed air diverter
valve.
BACKGROUND ART
[0002] 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 that is
introduced 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, thereby 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.
[0003] In many EGR applications, the exhaust gas is diverted by an
EGR valve directly from the exhaust manifold. The percentage of the
total exhaust flow which is diverted for reintroduction into the
intake manifold of an internal combustion engine is known as the
EGR flow rate of the engine.
[0004] Some internal combustion engines include turbochargers to
increase engine performance, and are available in a variety of
configurations. For example, fixed housing turbochargers have a
fixed exhaust inlet nozzle that accelerates exhaust gas towards a
turbine wheel, which in turn rotates a compressor. Also, a variable
nozzle turbocharger (VNT) has a variable nozzle having a ring of a
plurality of variable vanes which are controlled to change the
cross sectional area through which the exhaust gases pass to reach
the turbine. In a VNT, the smaller the nozzle opening, the faster
the gas velocity to the turbine, and in turn, the higher the boost.
Still further, it is known to provide a turbocharger having two
independent compressors, which is known as a double sided
compressor.
[0005] When utilizing EGR in a turbocharged diesel engine, the
exhaust gas to be recirculated is often removed upstream of the
exhaust gas driven turbine associated with the turbocharger. The
recirculated exhaust gas is typically introduced to the intake air
stream downstream of the compressor and air-to-air after-cooler
(ATAAC). Reintroducing the exhaust gas downstream of the compressor
and ATAAC is preferred in some systems due to the reliability and
maintainability concerns that arise if the exhaust gas passes
through the compressor and ATAAC.
[0006] The ability to supply EGR gases into the intake manifold
and/or fresh air into the exhaust manifold is a difficult task,
considering the high temperatures, exhaust corrosion and abrasion,
sealing needs, actuators and packaging constraints of prior EGR
systems. For example, U.S. Pat. No. 5,440,880 discloses a diesel
engine EGR system having a flow diverter valve positioned
immediately downstream of an EGR valve. The flow diverter valve is
controlled to modulate the portion of exhaust gas that is directed
to an after-cooler to be cooled prior to introduction into the
intake manifold, or directs exhaust gas directly to the intake
manifold. The exhaust gas that is directed to the after-cooler is
first conditioned by an exhaust gas conditioner to remove soot so
as to optimize the efficiency of the after-cooler.
[0007] At high speed and load, the pressure in the intake manifold
will be higher than that of the exhaust manifold. If a passageway
is opened between the intake and exhaust manifold under these
conditions, fresh air will flood into the exhaust manifold, thereby
significantly decreasing the engine performance.
[0008] The present invention is directed to overcoming one or more
of the problems or disadvantages associated with the prior art.
DISCLOSURE OF THE INVENTION
[0009] In one aspect of the invention, a valve is provided for use
in an EGR system for an internal combustion engine. The valve has a
housing having an exhaust inlet, an EGR outlet, an exhaust outlet
and a bleed air inlet. A butterfly plate is pivotally connected to
the housing. The butterfly plate has at least a first position and
a second position, wherein the first position defines a first fluid
path between the exhaust inlet and the EGR outlet and defines a
second fluid path between the bleed air inlet and the exhaust
outlet, and wherein the second position defines a third fluid path
between the exhaust inlet and the exhaust outlet and defines a
fourth fluid path between the bleed air inlet and the EGR
outlet.
[0010] In another aspect of the invention, provided is an internal
combustion engine, comprising a block defining a plurality of
combustion cylinders, the plurality of combustion cylinders having
a first group of combustion cylinders and at least one EGR pumping
cylinder. An intake manifold is connected to the block for
providing combustion air to each of the plurality of combustion
cylinders. A first exhaust manifold is connected to the block to
receive combustion gases from the first group of combustion
cylinders. A second exhaust manifold is connected to the block to
receive combustion gases from the at least one EGR pumping
cylinder. A turbocharger has a turbine and a compressor. The
turbine has an exhaust gas inlet port and an exhaust gas outlet
port, the exhaust gas inlet port of the turbine being coupled for
fluid communication with at least one of the first exhaust manifold
and the second exhaust manifold. A compressed air conduit is
coupled to provide fluid communication between a compressed air
outlet port of the compressor and the intake manifold. The
compressed air conduit has a bleed air port. A valve is provided
having a housing and a valve mechanism. The housing has an exhaust
inlet, an EGR outlet, an exhaust outlet and a bleed air inlet, the
exhaust inlet being connected in fluid communication with the
second exhaust manifold, the EGR outlet being connected in fluid
communication with the intake manifold, the exhaust outlet being
connected in fluid communication with the first exhaust manifold,
and the bleed air inlet being connected in fluid communication with
the bleed air port of the compressed air conduit. The valve
mechanism has at least a first position and a second position. The
first position defines a first fluid path between the exhaust inlet
and the EGR outlet and defines a second fluid path between the
bleed air inlet and the exhaust outlet. The second position defines
a third fluid path between the exhaust inlet and the exhaust outlet
and defines a fourth fluid path between the bleed air inlet and the
EGR outlet.
[0011] In still another aspect of the invention, provided is a
method of providing EGR for an internal combustion engine,
comprising the steps of providing a single valve having a housing
and a valve mechanism, the housing having an exhaust inlet, an EGR
outlet, an exhaust outlet and a bleed air inlet; positioning the
valve mechanism in a first position to define a first fluid path
between the exhaust inlet and the EGR outlet and to define a second
fluid path between the bleed air inlet and the exhaust outlet;
positioning the valve mechanism in a second position to define a
third fluid path between the exhaust inlet and the exhaust outlet
and to define a fourth fluid path between the bleed air inlet and
the EGR outlet; and positioning the valve mechanism between the
first position and the second position to simultaneously control an
amount of EGR gases and an amount of compressed bleed air supplied
in the internal combustion engine.
BRIEF DESCRIPTION OF THE DRAWINGS
[0012] FIG. 1 is a graphical illustration of an engine emission
control system of the invention.
[0013] FIG. 2 is a graphical illustration of an EGR/bleed air
diverter valve of the invention.
BEST MODE FOR CARRYING OUT THE INVENTION
[0014] Referring the drawings, there is shown in FIG. 1 a work
machine 10 having a frame 12 to which an internal combustion engine
14 is attached. Internal combustion engine 14 includes a block 16,
an intake manifold 18, a first exhaust manifold 20, a second
exhaust manifold 21, a turbocharger 22, and an EGR/bleed air
diverter valve 24.
[0015] As used herein, block 16 includes both an engine block and
cylinder head. Block 16 of internal combustion engine 14 includes a
plurality of combustion cylinders 26 (shown schematically by dashed
circles), and a corresponding plurality of reciprocating pistons
(not shown), each coupled to a crankshaft by a connecting rod (not
shown). The plurality of combustion cylinders 26 includes a first
group of combustion cylinders 27 and at least one EGR pumping
cylinder 28, such as for example a sixth cylinder in a six cylinder
engine, which is used to supply EGR gases. The general operation of
the components included in block 16 is well known in the art, and
for the sake of brevity, will not be further discussed herein.
[0016] Intake manifold 18 is connected to block 16 to supply
combustion air to combustion cylinders 26. The combustion air
includes both fresh air supplied from turbocharger 22 and EGR gases
supplied from EGR/bleed air diverter valve 24.
[0017] Each of first exhaust manifold 20 and second exhaust
manifold 21 is connected in fluid communication with block 16 to
receive combustion gases (also know as exhaust gases) from
combustion cylinders 26 following the combustion of an air/fuel
mixture in combustion cylinders 26. In particular, second exhaust
manifold 21 is coupled in fluid communication with EGR pumping
cylinder 28. As an alternative, first and second exhaust manifolds
20, 21 can be arranged to form a unitary manifold bank.
[0018] Turbocharger 22 includes a turbine 30 and a compressor 32.
Turbine 30 and compressor 32 are connected for mutual rotation via
a shaft 34.
[0019] Turbine 30 has an exhaust gas inlet port 40 and an exhaust
gas outlet port 42. Exhaust gas inlet port 40 of turbine 30 is
coupled in fluid communication to exhaust manifold 20 via exhaust
conduit 44. Exhaust gas outlet port 42 is coupled in fluid
communication with the atmosphere via an exhaust pipe 46 to expel
exhaust gases, depicted by arrow 48.
[0020] Compressor 32 has an air inlet port 50, and a compressed air
outlet port 52. Air inlet port 50 is connected in fluid
communication with the atmosphere via a conduit 54 to receive
atmospheric air, depicted by arrow 56, for combustion. Compressed
air outlet port 52 is coupled in fluid communication with intake
manifold 18 via compressed air conduit 58. Compressed air conduit
58 has a bleed air port 59.
[0021] EGR/bleed air diverter valve 24 has an exhaust inlet 60, an
EGR outlet 62, an exhaust outlet 63 and a bleed air inlet 64.
Exhaust inlet 60 is coupled in fluid communication with second
exhaust manifold 21. ERG outlet 62 is coupled in fluid
communication with intake manifold 18 via a conduit 66. Exhaust
outlet 63 is connected in fluid communication with first exhaust
manifold 20. Bleed air inlet 64 is coupled to bleed port 59 of
compressed air conduit 58 via a bleed line 68.
[0022] A valve controller 70 is coupled to EGR/bleed air diverter
valve 24 via an actuator 72, such as a rod or shaft.
[0023] As shown in FIG. 2, EGR/bleed air diverter valve 24 includes
a housing 74, a valve mechanism 76 and seal stops 78, 80, 82 and
84. As shown, valve mechanism 76 has a butterfly plate 85 and a
pivot shaft 86, with butterfly plate 85 being connected to pivot
shaft 86. Pivot shaft 86 is rotatably coupled to housing 74 via
apertures (not shown) formed in housing 74 for rotation in either
of a first direction, depicted by an arrow 88, and a second
direction, depicted by an arrow 90. Butterfly plate 85 has a first
side surface 92 and a second side surface 94.
[0024] Internal sealing in EGR/bleed air diverter valve 24 is
accomplished through tight tolerances of metal-to-metal contact
between butterfly plate 85 and seal stops 78, 80, 82, 84 of housing
74, and between pivot shaft 86 and the apertures in housing 74 that
pivotally support pivot shaft 86. Seal stops 78, 80, 82, 84 may be
machined into housing 74. As an alternative, the seal stops 78, 80,
82 and 84 could be made of a material other than metal, such as a
ceramic material. As shown in FIG. 2, seal stops 78 and 84 are
located to contact first side surface 92, at opposing ends of
butterfly plate 85. Seal stops 80 and 82 are located to contact
second side surface 94, at opposing ends of butterfly plate 85.
[0025] Valve controller 70 has a control unit 96 and an actuator
unit 98. Actuator unit 98 is coupled to pivot shaft 86 via actuator
72. In a simple form thereof, valve controller 70 may be a sensor
and actuator arrangement. In a more complex form thereof, control
unit 96 may have an electronic logic module, or microprocessor
system, in electrical communication with one or more sensors, such
as sensors for monitoring CO.sub.2 and/or NO.sub.x content of
exhaust gases, EGR flow rate, engine speed, exhaust gas temperature
and altitude, and in electrical or mechanical communication with
actuator unit 98. Actuator unit 98, for example, may have an
electrical solenoid, gear train and/or linkage system.
INDUSTRIAL APPLICABILITY
[0026] During operation, intake manifold 18 provides combustion air
to each of the plurality of combustion cylinders 26. First exhaust
manifold 20 receives combustion gases from the group of combustion
cylinders 27. Second exhaust manifold 21 receives combustion gases
from EGR pumping cylinder 28. Exhaust gases from at least one of
first exhaust manifold 20 and second exhaust manifold 21 are
received by turbocharger 22, thereby causing rotation of turbine
30, which in turn rotates compressor 32. Compressor 32 receives
atmospheric air 56 via air inlet port 50 and supplies a flow of
compressed air via compressed air outlet port 52. The flow of
compressed air is routed by compressed air conduit 58 to intake
manifold 18, except for the compressed bleed air which flows
through bleed air port 59.
[0027] EGR/bleed air diverter valve 24 is controlled to define
multiple positions of valve mechanism 76, including butterfly plate
85.
[0028] When butterfly plate 85 is in a first position, as shown by
solid lines in FIG. 2, a first fluid path is defined between
exhaust inlet 60 and EGR outlet 62, and a second fluid path is
defined between bleed air inlet 64 and exhaust outlet 63. When
butterfly plate 85 is positioned in the first position, butterfly
plate 85 contacts first seal stop 78 and second seal stop 80, and
does not contact third seal stop 82 and fourth seal stop 84. Also,
referring to FIGS. 1 and 2, in the first position a full flow of
exhaust gases is supplied from EGR pumping cylinder 28 to intake
manifold 18, and a full flow of compressed bleed air is supplied
from bleed air port 59 of compressed air conduit 58 to first
exhaust manifold 20. Thus, the first position permits internal
combustion engine 14 to operate with a full EGR flow (100 percent)
from EGR pumping cylinder 28 to intake manifold 18, and with full
bleed air flow (100 percent) to first exhaust manifold 20.
[0029] When butterfly plate 85 is in a second position, shown by
dashed lines in FIG. 2, a third fluid path is defined between
exhaust inlet 60 and exhaust outlet 63, and a fourth fluid path is
defined between bleed air inlet 64 and EGR outlet 62. When
butterfly plate 85 is positioned in the second position, butterfly
plate 85 contacts third seal stop 82 and fourth seal stop 84, and
does not contact first seal stop 78 and second seal stop 80. Also,
referring to FIGS. 1 and 2, in the second position a full flow of
exhaust gases is supplied from EGR pumping cylinder 28 to first
exhaust manifold 20, and a full flow of compressed bleed air is
supplied from bleed air port 59 of compressed air conduit 58 to
intake manifold 18. Thus, the second position permits internal
combustion engine 14 to operate with no EGR flow (0 percent) to
intake manifold 18 and with no bleed air flow (0 percent) to
exhaust manifold 20.
[0030] Butterfly plate 85 is variably positionable between the
first position (as depicted by solid lines) and the second position
(depicted by dashed lines) to simultaneously control an amount
and/or flow rate of EGR gases between 0 and 100 percent supplied to
intake manifold 18 and an amount and/or flow rate of compressed
bleed air between 0 and 100 percent supplied to first exhaust
manifold 20.
[0031] Thus, as shown in FIG. 2, it is apparent that EGR/bleed air
diverter valve 24 is designed so that an increase or decrease in
the amount and/or flow rate of EGR gases to intake manifold 18
resulting from a change in position of valve mechanism 76 results
in a corresponding increase or decrease, respectively, in the
amount and/or flow rate of compressed bleed air supplied to first
exhaust manifold 20.
[0032] The metal-to-metal seal design of EGR/bleed air diverter
valve 24 is effected such that seal stops 78, 80, 82 and 84 contact
respective side surfaces 92, 94 of butterfly plate 85. This permits
butterfly plate 85 to have a different thermal expansion than
housing 74 without seizing.
[0033] As shown in FIG. 2, actuator unit 98 of valve controller 70
is coupled to pivot shaft 86 of valve mechanism 76 via actuator 72
to effect the rotation thereof in a pivoting manner at the
directive of control unit 96. The commanded pivoting of shaft 86
variably positions butterfly plate at any position from the
above-mentioned first position through the above-mentioned second
position. Accordingly, EGR/bleed air diverter valve 24 provides
simultaneous control of an amount and/or flow rate of EGR gases
supplied to intake manifold 18 of internal combustion engine 14 and
an amount and/or flow rate of compressed bleed air supplied to
exhaust manifold 20 of internal combustion engine 14, using a
simple single valve design.
[0034] The use of a single valve to control both EGR and bleed air
paths advantageously reduces system costs by reducing the number of
valves, actuators and actuator drivers. The compact design of the
valve of the present invention permits the integration of the valve
into or near the exhaust manifold which reduces the overall volume
of the exhaust manifold and provides for good engine response.
[0035] Other aspects and features of the present invention can be
obtained from study of the drawings, the disclosure, and the
appended claims.
* * * * *