U.S. patent application number 13/549554 was filed with the patent office on 2014-01-16 for turbocharger system with reduced thrust load.
This patent application is currently assigned to GENERAL ELECTRIC COMPANY. The applicant listed for this patent is Neil Xavier Blythe, Cathal Clancy, Yu Du, Anthony Holmes Furman, Lukas William Johnson, Matthias Lang, Daniel Edward Loringer, Jonathan Edward Nagurney, Rodrigo Rodriguez Erdmenger, Kendall Roger Swenson. Invention is credited to Neil Xavier Blythe, Cathal Clancy, Yu Du, Anthony Holmes Furman, Lukas William Johnson, Matthias Lang, Daniel Edward Loringer, Jonathan Edward Nagurney, Rodrigo Rodriguez Erdmenger, Kendall Roger Swenson.
Application Number | 20140017099 13/549554 |
Document ID | / |
Family ID | 48692646 |
Filed Date | 2014-01-16 |
United States Patent
Application |
20140017099 |
Kind Code |
A1 |
Rodriguez Erdmenger; Rodrigo ;
et al. |
January 16, 2014 |
TURBOCHARGER SYSTEM WITH REDUCED THRUST LOAD
Abstract
An exemplary compressor is provided. The compressor includes a
plurality of blades, a hub defining a front surface and a back
surface, and a first flow restriction structure provided at the
back surface of the hub. The plurality of blades are arranged in a
predefined manner on the front surface for receiving input air flow
at a first pressure and compressing the input air flow to provide
an output air flow at a second pressure higher than the first
pressure. The first flow restriction member is configured for
preventing at least a portion of the output air flow at the second
pressure from entering into the back surface of the hub to reduce
an air pressure at the back surface of the hub.
Inventors: |
Rodriguez Erdmenger; Rodrigo;
(Munich, DE) ; Swenson; Kendall Roger; (Eureka,
CA) ; Loringer; Daniel Edward; (Erie, PA) ;
Furman; Anthony Holmes; (Scotia, NY) ; Blythe; Neil
Xavier; (North East, PA) ; Johnson; Lukas
William; (Erie, PA) ; Nagurney; Jonathan Edward;
(Erie, PA) ; Du; Yu; (Munich, DE) ; Clancy;
Cathal; (Munich, DE) ; Lang; Matthias;
(Munich, DE) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Rodriguez Erdmenger; Rodrigo
Swenson; Kendall Roger
Loringer; Daniel Edward
Furman; Anthony Holmes
Blythe; Neil Xavier
Johnson; Lukas William
Nagurney; Jonathan Edward
Du; Yu
Clancy; Cathal
Lang; Matthias |
Munich
Eureka
Erie
Scotia
North East
Erie
Erie
Munich
Munich
Munich |
CA
PA
NY
PA
PA
PA |
DE
US
US
US
US
US
US
DE
DE
DE |
|
|
Assignee: |
GENERAL ELECTRIC COMPANY
Schenectady
NY
|
Family ID: |
48692646 |
Appl. No.: |
13/549554 |
Filed: |
July 16, 2012 |
Current U.S.
Class: |
417/244 ;
415/208.1; 417/406 |
Current CPC
Class: |
F04D 29/051 20130101;
F04D 29/162 20130101; F05D 2220/40 20130101; F04D 29/0516 20130101;
F04D 25/04 20130101; F04D 29/284 20130101 |
Class at
Publication: |
417/244 ;
415/208.1; 417/406 |
International
Class: |
F01D 1/06 20060101
F01D001/06; F04D 17/10 20060101 F04D017/10 |
Claims
1. A compressor comprising: a plurality of blades; a hub defining a
front surface and a back surface, the plurality of blades being
arranged in a predefined manner on the front surface for receiving
input air flow at a first pressure and compressing the input air
flow to provide an output air flow at a second pressure higher than
the first pressure; and a first flow restriction member provided at
the back surface of the hub, the first flow restriction member
configured for preventing at least a portion of the output air flow
at the second pressure from entering into the back surface of the
hub to reduce an air pressure at the back surface of the hub.
2. The compressor of claim 1, wherein the first flow restriction
member is formed integral with the back surface of the hub.
3. The compressor of claim 1, wherein the first flow restriction
member is detachably coupled to the back surface of the hub.
4. The compressor of claim 1, wherein the first flow restriction
member extends from the back surface of the hub along a direction
substantially parallel to a rotation axis that the hub rotates
therewith, the first flow restriction member operates to deflect
the air flow entering into the back surface of the hub and create a
pressure difference at two sides of the first flow restriction
member.
5. The compressor of claim 1, wherein the first flow restriction
member extends along a circumferential direction to form a
ring-shaped member protruding backwardly from the back surface of
the hub, the ring-shaped first flow restriction member divides the
back surface into at least a first region and a second region, the
first region is adjacent to the edge of the hub and the second
region is adjacent to a rotational axis of the hub, wherein the
first region has an air pressure higher than that of the second
region during rotational movement of the hub.
6. The compressor of claim 1, wherein the first flow restriction
member comprises: a first surface extending substantially
perpendicular to the back surface of the hub, the first surface
deflecting at least a portion of the output air flow at the second
pressure that enters into the back surface from a first direction
to a second direction; and a second surface connecting to the first
surface, the second surface extending substantially parallel to the
back surface, the second surface further deflecting the air flow
from the second direction back to the first direction.
7. The compressor of claim 6, wherein the first restriction member
further comprises a third surface connecting to the second surface
and the back surface, the third surface extending substantially
perpendicular to the back surface, the third surface further
deflecting the air flow from the first direction to a third
direction which is opposite to the second direction.
8. The compressor of claim 6, wherein the compressor is capable of
being enclosed in a housing which comprises a first wall running
substantially parallel to the first surface of the first flow
restriction member, the first wall and the first surface defines a
flow channel which has a first dimension when the first flow
restriction member is stationary with respect to the hub and a
second dimension when the first restriction member is rotating with
the hub, wherein the second dimension is smaller than the first
dimension due to a centrifugal force applied at the first flow
restriction member when the hub is rotating.
9. The compressor of claim 1, wherein the back surface of the hub
is further provided with a second flow restriction member
constructed substantially similar to the first flow restriction
member, the first and second restriction members are spaced apart
along a radial direction of the compressor.
10. A turbocharger system for an internal combustion engine, the
turbocharger system comprising: a turbine in flow communication
with an exhaust manifold of the internal combustion engine for
receiving exhaust gas discharged from the exhaust manifold and
being driven to rotate by the exhaust gas; a compressor coupled to
the turbine through a drive shaft, the compressor driven to rotate
by the drive shaft in response to a rotation of the turbine for
supplying pressurized air to an intake of the internal combustion
engine; and a thrust bearing attached to the drive shaft for
supporting at least a thrust load applied along an axial direction
of the drive shaft; wherein the compressor comprises a hub defining
a back surface provided with a flow restriction member, the flow
restriction member deflects a flow path of at least a portion of
the pressurized air entering into the back surface at least once to
create a pressure difference between two areas at least partially
defined by the flow restriction member, and the pressure difference
created by the flow restriction member causes the thrust load
applied along the axial direction of the drive shaft to be
reduced.
11. The turbocharger system of claim 10, wherein the compressor is
at least partially enclosed within a compressor housing, the flow
restriction member is capable of being moved along a radial
direction of the hub in response to a rotational movement of the
hub and the dimension of a flow channel defined between the flow
restriction member and a wall of the compressor housing is reduced
due to the radial movement of the flow restriction member to reduce
the amount of the pressurized air entering to the back surface of
the hub.
12. The compressor of claim 10, wherein the flow restriction member
extends from the back surface along a direction substantially
parallel to a rotation axis that the hub rotates therewith, the
flow restriction member operates to deflect the pressurized air
entering into the back surface of the hub and create a pressure
difference at two sides of the flow restriction member.
13. The compressor of claim 10, wherein the flow restriction member
extends along a circumferential direction to form a ring-shaped
member protruding backwardly from the back surface of the hub, the
ring-shaped flow restriction member divides the back surface into
at least a first region and a second region, the first region is
adjacent to the edge of the hub and the second region is adjacent
to the drive shaft, wherein the first region has an air pressure
higher than that of the second region during rotational movement of
the hub.
14. A multi-stage turbocharger system for an internal combustion
engine, the multi-stage turbocharger comprising: a low-pressure
stage comprising: a low-pressure turbine; and a low-pressure
compressor capable of being driven by the low-pressure turbine to
compress input air flow at a first air pressure and provide
intermediate air flow at a second air pressure higher than the
first air pressure; and a high-pressure stage comprising: a
high-pressure turbine; and a high-pressure compressor placed
downstream of the low-pressure compressor, the high-pressure
compressor capable of being driven by the high-pressure turbine to
compress at least a portion of the intermediate air flow provided
from the low-pressure compressor and supply output air flow at a
third air pressure higher than the second air pressure to an intake
of the internal combustion engine; wherein the high-pressure
compressor is in flow communication with the low-pressure
turbine.
15. The multi-stage turbocharger system of claim 14, wherein the
low-pressure stage further comprises: a low-pressure drive shaft
for coupling the low-pressure turbine to the low-pressure
compressor; and a low-pressure thrust bearing attached to the
low-pressure drive shaft for supporting at least a thrust load
applied along an axial direction of the low-pressure drive shaft;
wherein at least a portion of the output air flow provided from the
high-pressure compressor is diverted to a back surface of the
low-pressure turbine to increase the air pressure at the back
surface of the low-pressure turbine and reduce the thrust load
applied along the axial direction of the low-pressure drive
shaft.
16. The multi-stage turbocharger system of claim 14, wherein the
low-pressure compressor comprises a flow restriction member
provided at a back surface of the low-pressure compressor, the flow
restriction member deflects a flow path of at least a portion of
the intermediate air flow entering into the back surface of the
low-pressure compressor at least once to create a pressure
difference between two areas at least partially defined by the flow
restriction member, and the pressure difference created by the flow
restriction member causes the thrust load applied along the axial
direction of the low-pressure drive shaft to be reduced.
17. The multi-stage turbocharger system of claim 16, wherein the
flow restriction member extends along a circumferential direction
to form a ring-shaped member protruding backwardly from the back
surface of the low-pressure compressor, the ring-shaped flow
restriction member divides the back surface of the low-pressure
compressor into at least a first region and a second region, the
first region is adjacent to the edge of the low-pressure compressor
and the second region is adjacent to the low-pressure drive shaft,
wherein the first region has an air pressure higher than that of
the second region during rotational movement of the low-pressure
compressor.
18. The multi-stage turbocharger system of claim 16, wherein the
flow restriction member is capable of being moved along a radial
direction of the low-pressure compressor in response to a
rotational movement of the low-pressure compressor and the
dimension of a flow channel defined between the flow restriction
member and a wall of a compressor housing is reduced due to the
radial movement of the flow restriction member to reduce the amount
of the intermediate air flow entering to the back surface of the
low-pressure compressor.
19. The multi-stage turbocharger system of claim 14, wherein the
low-pressure compressor comprises a first flow restriction member
and a second flow restriction member provided at a back surface of
the low-pressure compressor, the first and second restriction
members are spaced apart along a radial direction of the back
surface of the low-pressure compressor, and the first and second
restriction members operate to deflect a flow path of at least a
portion of the intermediate air flow entering into the back surface
of the low-pressure compressor at least once to create a pressure
difference between areas at least partially defined by the first
and second flow restriction members, and the pressure difference
created by the flow restriction member causes the thrust load
applied along the axial direction of the low-pressure drive shaft
to be reduced.
20. The multi-stage turbocharger system of claim 18, wherein the
first and second flow restriction members extend along a
circumferential direction to form ring-shaped members protruding
backwardly from the back surface of the low-pressure compressor,
the ring-shaped flow restriction members divide the back surface of
the low-pressure compressor into at least a first region, a second
region, and a third region, wherein the air pressure of the second
region is smaller than that of the first region and greater than
that of the third region.
Description
BACKGROUND
[0001] Embodiments of the disclosure relate generally to
turbocharger system used for engines such as internal combustion
engines and more particularly to an improved compressor of the
turbocharger system and an improved multi-stage turbocharger system
for thrust load reduction.
[0002] Turbocharger is a forced induction device used in an engine
such as an internal combustion engine. In general, the turbocharger
operates to allow more power to be produced from the internal
combustion engine. The turbocharger typically includes a turbine
and a compressor that are coupled to each other via a drive shaft.
During operation, exhaust gas discharged from an exhaust manifold
of the internal combustion engine drives the turbine to rotate
which in turn drives the drive shaft and the compressor to rotate.
The compressor then compresses input air flow at an atmospheric
pressure and provides compressed air at a boosted pressure to the
inlet of the internal combustion engine. Because the compressed air
forced into the inlet of the internal combustion engine contains
more oxygen content, the power produced by the internal combustion
engine can be increased as more fuel can be combusted in the
cylinders of the internal combustion engine.
[0003] The turbocharger also utilizes one or more bearing devices
to support various loads applied to the drive shaft. For example, a
thrust bearing is typically used to support a thrust load applied
along an axial direction of the drive shaft. The thrust load can be
generated either by a pressure distribution in the turbocharger or
by the momentum of the flow in the turbocharger. Too large thrust
load leads to a reduced life of the thrust bearing. Therefore, it
is desirable to provide turbocharger systems capable of reducing
the thrust load.
BRIEF DESCRIPTION
[0004] In accordance with one embodiment disclosed herein, a
compressor is provided. The compressor includes a plurality of
blades, a hub defining a front surface and a back surface, and a
first flow restriction structure provided at the back surface of
the hub. The plurality of blades are arranged in a predefined
manner on the front surface for receiving input air flow at a first
pressure and compressing the input air flow to provide an output
air flow at a second pressure higher than the first pressure. The
first flow restriction member is configured for preventing at least
a portion of the output air flow at the second pressure from
entering into the back surface of the hub to reduce an air pressure
at the back surface of the hub.
[0005] In accordance with another embodiment disclosed herein, a
turbocharger system for an internal combustion engine is provided.
The turbocharger system includes a turbine, a compressor, and a
thrust bearing. The turbine is in flow communication with an
exhaust manifold of the internal combustion engine for receiving
exhaust gas discharged from the exhaust manifold and is driven to
rotate by the exhaust gas. The compressor is coupled to the turbine
through a drive shaft. The compressor is driven to rotate by the
drive shaft in response to a rotation of the turbine for supplying
pressurized air to an intake of the internal combustion engine. The
thrust bearing is attached to the drive shaft for supporting at
least a thrust load applied along an axial direction of the drive
shaft. The compressor includes a hub defining a back surface
provided with a flow restriction member. The flow restriction
member deflects a flow path of at least a portion of the
pressurized air entering into the back surface at least once to
create a pressure difference between two areas at least partially
defined by the flow restriction member, and the pressure difference
created by the flow restriction member causes the thrust load
applied along the axial direction of the drive shaft to be
reduced.
[0006] In accordance with another embodiment disclosed herein, a
multi-stage turbocharger system for an internal combustion engine
is provided. The multi-stage turbocharger includes a low-pressure
stage and a high-pressure stage. The low-pressure stage includes a
low-pressure turbine and a low-pressure compressor. The
low-pressure compressor is capable of being driven by the
low-pressure turbine to compress input air flow at a first air
pressure and provide intermediate air flow at a second air pressure
higher than the first air pressure. The high-pressure stage
includes a high-pressure turbine and a high-pressure compressor.
The high-pressure compressor is placed downstream of the
low-pressure compressor. The high-pressure compressor is capable of
being driven by the high-pressure turbine to compress at least a
portion of the intermediate air flow provided from the low-pressure
compressor and supply output air flow at a third air pressure
higher than the second air pressure to an intake of the internal
combustion engine. The high-pressure compressor is in flow
communication with the low-pressure turbine.
DRAWINGS
[0007] These and other features, aspects, and advantages of the
present disclosure will become better understood when the following
detailed description is read with reference to the accompanying
drawings in which like characters represent like parts throughout
the drawings, wherein:
[0008] FIG. 1 illustrates a sectional view of a compressor in
accordance with an exemplary embodiment of the present
disclosure;
[0009] FIG. 2 is a perspective view of the compressor shown in FIG.
1 in accordance with an exemplary embodiment of the present
disclosure;
[0010] FIG. 3 is a back side elevation view of the compressor shown
in FIG. 1 in accordance with an exemplary embodiment of the present
disclosure;
[0011] FIG. 4 is an enlarged view of a portion of the compressor
shown in FIG. 1 operating in a first state in accordance with an
exemplary embodiment of the present disclosure;
[0012] FIG. 5 is an enlarged view of a portion of the compressor
shown in FIG. 1 operating in a second state in accordance with an
exemplary embodiment of the present disclosure;
[0013] FIG. 6 illustrates a sectional view of a compressor in
accordance with another exemplary embodiment of the present
disclosure;
[0014] FIG. 7 illustrates a sectional view of a compressor in
accordance with yet another exemplary embodiment of the present
disclosure;
[0015] FIG. 8 illustrates a schematic block diagram of a
single-stage turbocharger system used for an internal combustion
engine in accordance with an exemplary embodiment of the present
disclosure;
[0016] FIG. 9 illustrates a schematic block diagram of a two-stage
turbocharger system used for an internal combustion engine in
accordance with an exemplary embodiment of the present disclosure;
and
[0017] FIG. 10 illustrates a schematic block diagram of a two-stage
turbocharger system used for an internal combustion engine in
accordance with another exemplary embodiment of the present
disclosure.
DETAILED DESCRIPTION
[0018] In an effort to provide a concise description of these
embodiments, not all features of an actual implementation are
described in the one or more specific embodiments. It should be
appreciated that in the development of any such actual
implementation, as in any engineering or design project, numerous
implementation-specific decisions must be made to achieve the
developers' specific goals, such as compliance with system-related
and business-related constraints, which may vary from one
implementation to another. Moreover, it should be appreciated that
such a development effort might be complex and time consuming, but
would nevertheless be a routine undertaking of design, fabrication,
and manufacture for those of ordinary skill having the benefit of
this disclosure.
[0019] Unless defined otherwise, technical and scientific terms
used herein have the same meaning as is commonly understood by one
of ordinary skill in the art to which this disclosure belongs. The
terms "first", "second", and the like, as used herein do not denote
any order, quantity, or importance, but rather are used to
distinguish one element from another. Also, the terms "a" and "an"
do not denote a limitation of quantity, but rather denote the
presence of at least one of the referenced items. The term "or" is
meant to be inclusive and mean either any, several, or all of the
listed items. The use of "including," "comprising" or "having" and
variations thereof herein are meant to encompass the items listed
thereafter and equivalents thereof as well as additional items. The
terms "connected" and "coupled" are not restricted to physical or
mechanical connections or couplings, and can include electrical
connections or couplings, whether direct or indirect.
[0020] Embodiments of the present disclosure generally relate to
thrust load reduction for turbocharger systems. The turbocharger
systems are used for improving efficiency of engines such as
internal combustion engines. In one embodiment, a compressor with
at least one flow restriction structure is provided. Specifically,
the flow restriction structure is provided at the back surface for
preventing at least a portion of pressurized air flow produced by
the compressor from entering at the back surface. Thus, the air
pressure at the back surface can be reduced. Reducing the back
surface pressure results in a reduced thrust load applied at a
thrust bearing. As a result, over-wearing problems of the thrust
bearing can be avoided and the life of the thrust bearing can be
extended. In another embodiment, a two-stage turbocharger system is
provided. The two-stage turbocharger system includes a
high-pressure stage turbocharger system and a low-pressure stage
turbocharger system. In one implementation, at least a portion of
the pressurized air flow produced by a high-pressure compressor of
the high-pressure stage turbocharger system is diverted to a back
surface of a low-pressure turbine of the low-pressure stage
turbocharger system to increase the air pressure at the back
surface of the low-pressure turbine. Thus, the net thrust load
applied to a low-pressure thrust bearing in the low-pressure stage
turbocharger system can be reduced to avoid over-wearing problems
of the low-pressure thrust bearing and/or extend or prolong the
life of the low-pressure thrust bearing.
[0021] Referring to FIG. 1, a sectional view of compressor 20 is
illustrated in accordance with an exemplary embodiment of the
present disclosure. The compressor 20 can be used in a turbocharger
system for supplying pressurized air directly or indirectly to an
engine. For example, the compressor 20 may be used in a
single-stage turbocharger system 400 shown in FIG. 8 for supplying
pressurized air directly to engine 440. For another example, the
compressor 20 may be used in two-stage turbocharger systems 600,
700 shown in FIG. 9 or FIG. 10 respectively for supplying
pressurized air to engine 602. It can be understood the compressor
20 can also be used in other multistage turbocharger systems. The
single-stage turbocharger system 400 and the two-stage turbocharger
systems 600, 700 will be described with more details below. Also,
other than the turbocharger systems 600, 700 shown in FIGS. 8-10,
one skilled in the art can contemplate that the compressor 20 with
the one or more improved features described below, for example,
features for thrust load reduction, can be equally used in other
industrial applications, including but not limited to, gas turbines
and steam turbines for example.
[0022] In one implementation, the compressor 20 shown in FIG. 1 may
be a centrifugal compressor that can be driven to rotate at certain
speed such that an input air flow 212 at a first air pressure
received from a first air supplying source can be compressed to
provide compressed/pressurized output air flow 214 at a second air
pressure. The second air pressure is typically higher than the
first air pressure. In one embodiment, the input air flow 212 can
be received directly from the atmosphere and the first air pressure
is the atmospheric pressure. In another embodiment, the input air
flow 212 may be taken from an upstream compressor which supplies an
output air flow at a boosted pressure higher than the atmospheric
pressure.
[0023] Further referring to FIG. 1, in one implementation, the
compressor 20 generally includes a hub 220 which is fixedly mounted
to one end of a drive shaft 30. The other end of the drive shaft 30
may be coupled to a turbine (not shown in FIG. 1) which can be
driven to rotate by exhaust gas discharged from an engine for
example. The hub 220 can be driven to rotate around a rotational
axis 302 in response to rotational movement of the turbine. In one
implementation, as shown in FIG. 2 and FIG. 3, the hub 220 may
define a center bore 229. One end of the drive shaft 30 can extend
through the center bore 229 and is secured with the hub 220 via
nuts or screws for example. The hub 220 generally defines a first
surface 216 and a second surface 218. The first surface 216 is a
front surface facing the input air flow 212. The first surface 216
is provided with a plurality of blades 215. The plurality of blades
215 can be spaced apart on the first surface 216 in a predetermined
manner to define a plurality of air channels for the input air flow
212 to pass through. As shown in FIG. 1, the input air flow 212 may
generally flow along a horizontal direction parallel to the axial
direction 302 of the drive shaft 30. After compression, the output
air flow 214 generally flows along the vertical direction or radial
direction 210 of the compressor 20. The second surface 228 is a
back surface or rear surface that is disposed adjacent to wall of a
compressor housing 240. More specifically, a space is defined
between the back surface 218 and the wall of the compressor housing
240 to allow the compressor 20 rotate without contacting the
compressor housing 240.
[0024] Without a sealing structure arranged between the output air
flow 214 and the space defined between the back surface 218 and
wall of the compressor housing 240, a portion of the output air
flow 214 or a leakage air flow 222 may enter into the space. The
leakage air flow 222 in the space has an air pressure which
generates a back-surface axial thrust force/load 217 pointing from
the back surface 218 to the front surface 216. The back-surface
axial thrust force/load 217 then is transmitted through the drive
shaft 30 to a thrust bearing 304 attached to the drive shaft 30.
Too large back-surface axial thrust force 217 may cause
over-wearing problems of the thrust bearing 304 and may thus reduce
the life of the thrust bearing 304. Therefore, to avoid
over-wearing problems and/or to extend or prolong the life of the
thrust bearing 304, it is desirable to reduce the amount of the
leakage air flow 222 at the back surface 218 so as to reduce the
axial thrust force/load 217 applied at the thrust bearing 304.
[0025] In one implementation, to reduce the amount of leakage
airflow 222 at the back surface 218 or prevent at least a portion
of the output air flow 214 from entering into the space at least
partially enclosed by the back surface 218, a flow restriction
structure 224 is introduced at the back surface 218. The flow
restriction structure 224 generally divides the space into a first
region 226 and a second region 228. The first region 226 is located
adjacent to the edge of the compressor 20 where the output air flow
214 is produced. The second region 228 is located adjacent to a
center of the compressor 20 where the drive shaft 30 is mounted. In
general, the flow restriction structure 224 can be viewed as a flow
deflection mechanism which functions to deflect or change a flow
path of the leakage air flow 222 such that the leakage air flow 222
is made more difficult flowing from the first region 226 to the
second region 228. The flow restriction structure 224 can also be
viewed as a flow path extension mechanism which extends the flow
path for the leakage air flow 222 to pass through. For example, the
flow restriction structure 224 may create a non-linear flow path
for the leakage air flow 222 to pass through. Due to flow
deflection mechanism or the flow path extension mechanism, the
amount of air flow in the second region 228 is less than that in
the first region 226 or an air pressure difference is created
between the first and second regions 226, 228. That is, the air
pressure at the first region 226 is larger than that in the second
region 228. As a result, a combined air pressure of the first
region 226 and the second region 228 is reduced and the reduced air
pressure leads to a reduced thrust load 217 applied at the thrust
bearing 304.
[0026] Further referring to FIG. 1, in one implementation, the flow
restriction structure 224 includes a first restriction section 223
and a second restriction section 225. In one implementation, the
first restriction section 223 is a member that generally protrudes
backwardly from the back surface 218 of the hub 220 and extends
along the axial direction 302 of the drive shaft 30. The second
restriction section 225 is a groove or recess defined in a wall of
the compressor housing 240 for non-contactively receiving the first
restriction section/member 223 therein. In other implementations,
the first restriction section 223 and the second restriction
section 225 may exchange roles. For example, the first restriction
section 223 may be a member protruding forwardly from the wall of
the compressor housing 240 and the second restriction section 224
is a groove or recess defined in the back surface 218 of the hub
220 for receiving the first restriction section 223 therein.
[0027] Further referring to FIG. 1, the first restriction section
223 may be formed integrally with the back surface 218 of the hub
220. In other implementations, the first restriction section 223
may be detachably coupled to the back surface 218 of the hub 220.
Referring also to FIGS. 2 and 3, the first restriction section 223
may also extend along a circumferential direction 227 at the back
surface 218 to form a ring-shaped member. In other implementations,
the first restriction section 233 is not necessarily extending
continuously along the circumferential direction 227 of the back
surface 218. For example, the first restriction section 233 may
include multiple elements separately arranged along the
circumferential direction 227 of the back surface 218. In the
illustrated embodiment, the ring-shaped first restriction section
223 divides the back surface 218 into a first region 226 and a
second region 228.
[0028] Referring to FIG. 4, an enlarged view of a portion of the
compressor 20 including the flow restriction structure 224 is shown
in accordance with an exemplary embodiment of the present
disclosure. More specifically, the first restriction section 223 of
the flow restriction structure 224 defines a first surface 232, a
second surface 234, and a third surface 236. The second restriction
section 225 of the flow restriction structure 224 is a groove
defined by a first wall 242, a second wall 244, and a third wall
246. As shown in FIG. 4, the leakage air flow 222 initially flows
along a first channel 235 which is generally parallel to the radial
direction 210 of the compressor 20. As used herein, "radial
direction" is generally defined as a direction extending from a
center at which a drive shaft 30 is mounted to an edge of the
compressor 20 where the output air flow 214 is produced. The
leakage air flow 222 is then deflected to flow in a second channel
237 defined between the first surface 232 and the first wall 242.
The second channel 237 is substantially parallel to the axial
direction 302 of the drive shaft 30. The leakage air flow 222
flowing in the second channel 237 is further deflected to flow in a
third channel 239 defined between the second surface 234 and the
second wall 244. The third channel 239 is substantially parallel to
the radial direction 210. The leakage air flow 222 flowing in the
third channel 239 is further deflected to flow in a fourth channel
241 defined between the third surface 236 and the third wall 246.
The fourth channel 241 is substantially parallel to the axial
direction 302 of the drive shaft 30. Due to the deflection
mechanism, the leakage air flow 222 is made difficult to reach the
second region 228 such that the air pressure at the back surface
218 of the compressor 20 can be reduced.
[0029] Further referring to FIG. 4 and FIG. 5, in which FIG. 4
shows the compressor 20 in a stationary state or a non-rotational
state and FIG. 5 shows the compressor 20 in a rotational state. In
this stationary state, the channel 237 defined between the first
surface 232 and the first wall 242 has a first dimension of
d.sub.1. In the rotational state or when the compressor 20 is
rotating, a centrifugal force applied to the first restriction
section 223 causes the first restriction section 223 to move along
the radial direction 210 and away from the center. That is, the
first surface 232 tend to approach the first wall 242 of the
compressor housing 240. As the compressor housing 240 remains
stationary, the first channel 237 defined between the first surface
232 and the first wall 242 is reduced to have a second dimension of
d.sub.2 which is smaller than the first dimension d.sub.1. The flow
channel 237 with reduced dimension makes the leakage air flow even
more difficult to reach the second region 228. As a result, the
second region 228 can be substantially sealed with respect to the
first region 226.
[0030] FIG. 6 illustrates a sectional view of a compressor 20 in
accordance with another exemplary embodiment of the present
disclosure. The embodiment shown in FIG. 6 is substantially similar
to that has been described with reference to FIG. 1. Thus, similar
elements will not be described with details in this embodiment. In
the illustrated embodiment, the flow restriction member 224 is
further configured for balancing purposes. During manufacturing
process of the compressor, various factors such as irregularities
in mass distribution can make the compressor unbalanced which means
that rotational movement of the compressor 20 is substantially
eccentric. Conventionally, scalloping means has been employed which
removes material at the outer edge and between blades of the
compressor wheel for balancing the compressor. However, scalloping
the hub of the compressor can bring performance penalties to the
compressor. For example, more output air flow may be leaked from
the scalloped area to the back surface of the compressor. In the
illustrated embodiment, balancing of the compressor 20 is achieved
by removing material from the first restriction section 223
protruding backwardly at the back surface 218 of the compressor 20.
The specific amount and location of the material to be removed from
the first restriction section 223 is determined according to
practical requirements. After balanced, the rotational movement of
the compressor 20 can be substantially concentric. It should be
understood that other than the weight-removal features as described
herein, in some embodiments, the flow restriction member 224 may be
added with some material for balancing the compressor 20. Also, the
amount and location of the added material is determined according
to the practical requirements.
[0031] As described with reference to FIGS. 1-3, the back surface
218 of the compressor 20 is provided with one flow restriction
structure 224 used for reducing the air pressure at the back
surface 218. However, to achieve air pressure reduction, the back
surface 218 can be provided with more than one flow restriction
structures. For example, FIG. 7 shows another embodiment of the
compressor 20 in which two flow restriction structures are
included. In the illustrated embodiment, the back surface 218 of
the compressor 20 is provided with a first flow restriction
structure 252 and a second flow restriction structure 254. The
first and second flow restriction structures 252, 254 has
configurations that are similar to the flow restriction structure
224 described above with reference to FIGS. 1-3. More specifically,
the first flow restriction structure 252 and the second flow
restriction structure 254 are spaced apart along the radial
direction 210 and divide the back surface into a first region 226,
a second region 227, and a third region 228. The first flow
restriction member 252 deflects the leakage air flow 222 and
creates an air pressure difference between the first region 226 and
the second region 227. That is, the air pressure at the second
region 227 is smaller than the first region 226. Further, the
second flow restriction structure 254 deflects the leakage air flow
222 and creates an air pressure difference between the second
region 227 and the third region 228. That is, the air pressure at
the third region 228 is smaller than the second region 227. In
addition, the radial movement of the first and second flow
restriction structures 252, 254 with respect to the wall of the
compressor housing 240 can further reduce the amount of leakage air
flow 222 at the back surface 218 of the compressor. Thus, the air
pressure at the back surface 218 can be significantly reduced
thereby the axial thrust load 217 applied to the thrust bearing 304
can be reduced. Therefore, over-wearing problems of the thrust
bearing 304 can be avoided and/or the life of the thrust bearing
304 can be prolonged or extended.
[0032] Further referring to FIG. 7, in some embodiments, either one
or both of the first and second flow restriction members 252, 254
can be used for balancing of the compressor 20. More specifically,
in one implementation, the first flow restriction structure 252 is
partially removed with material for balancing. In another
implementation, the second flow restriction structure 254 is
partially removed with material for balancing. In yet another
implementation, both the first and second flow restriction
structures 252, 254 are removed with material for balancing. Still
in some implementations, either one or both of the first and second
flow restriction members 252, 254 can be added with material for
balancing.
[0033] FIG. 8 illustrates a single-stage turbocharger system 400 in
which the various compressor embodiments described above can be
implemented. More specifically, the single-stage turbocharger
system 400 includes a turbine 402 and a compressor 404 that are
coupled to each other via a drive shaft 406. The compressor 404 can
has substantially the same configuration as the compressor 20
described above with reference to FIGS. 1-7. For example, one or
more flow restriction structures 224 can be provided at the back
surface 452 of the compressor 404. The turbocharger system 400
further includes a thrust bearing 408 which is schematically shown
as being attached to the drive shaft 406 for supporting the thrust
load 456 applied to the drive shaft 406. The thrust bearing 408 is
a known element in the art, and thus detailed description of the
thrust bearing 408 is omitted here. In the illustrated embodiment,
the thrust load 456 is a net thrust load pointing from the turbine
402 side to the compressor 404 side and is parallel to the axial
direction 302 of the drive shaft 406. The net thrust load 456
includes at least a compressor back-surface thrust load 458
component which is generated due to the leakage air flow at the
back surface 452 of the compressor 404. The compressor back-surface
thrust load 458 points substantially at the same direction as that
of the net thrust load 456. Thus, reducing the compressor
back-surface thrust load 458 can lead to a reduction of the net
thrust load 456.
[0034] Further referring to FIG. 8, the turbine 402 is placed
downstream of the exhaust manifold 444 of the engine 440 (e.g., an
internal combustion engine) for receiving exhaust gas discharged
from the exhaust manifold 444 and routed through an exhaust channel
446. The exhaust gas passes through the turbine 402 and drives the
turbine 402 to rotate. The turbine 402 then drives the shaft 406
and compressor 404 to rotate. In one embodiment, a portion of the
exhaust gas passing through the turbine 402 is discharged directly
to the environment. In another embodiment, the exhaust gas passing
through the turbine 402 may be re-circulated.
[0035] Further referring to FIG. 8, the compressor 404 compresses
input air flow 412 and produces output air flow 413 at boosted air
pressure. In the illustrated embodiment, the output air flow 413 is
routed to an intercooler 416 via a first channel 414. The
intercooler 416 functions as a heat exchanger to remove heat from
the output air flow 413 as a result of the compression process. The
cooled output air flow is routed to an intake manifold 442 via a
second channel 418. In other embodiments, the output air flow 413
produced from the compressor 404 may be directly routed to the
intake manifold 442 of the engine 440 without intercooling.
[0036] During operation, the one or more flow restriction
structures 454 provided at the back surface 452 of the compressor
404 functions to reduce the amount of leakage air flow entering at
back surface 452 of the compressor 404. The reduced leakage air
flow leads to a reduced compressor back-surface thrust load/force
458 and a reduced net thrust load 456 applied at the thrust bearing
408. As a result, over-wearing problems of the thrust bearing 408
can be avoided and/or the life of the thrust bearing 408 can be
extended or prolonged.
[0037] Further referring to FIG. 8, in some embodiments, the one or
more flow restriction structures 454 provided at the back surface
452 of the compressor 404 can be modified for balancing the
compressor 20. For example, a portion of the flow restriction
structure 454 can be removed for balancing. In another embodiment,
the flow restriction structure 454 can be added with material for
balancing.
[0038] In other implementations, the compressor 20 described with
reference to FIGS. 1-7 can be used in a two-stage turbocharger
system 600. The two-stage turbocharger system 600 is configured for
supplying pressurized air to engine 602 to improve the efficiency
of the engine 602. Referring to FIG. 9, in one embodiment, the
engine 602 includes an internal combustion engine. In the
illustrated embodiment, the internal combustion engine 602 includes
a plurality of cylinders or combustion chambers 604 for combusting
fuels and gas supplied through intake manifold 606. After
combustion, the exhaust gas is discharged from the exhaust manifold
608.
[0039] Further referring to FIG. 9, the two-stage turbocharger
system 600 includes a high-pressure stage turbocharger system 620
and a low-pressure stage turbocharger system 640 in flow
communication with each other. The high-pressure stage turbocharger
system 620 includes a high-pressure turbine 622 and a high-pressure
compressor 624 coupled to each other via a high-pressure drive
shaft 626. The low-pressure turbocharger system 640 includes a
low-pressure turbine 642 and a low-pressure compressor 644 coupled
to each other via a low-pressure drive shaft 646. The exhaust gas
discharged from the exhaust manifold 608 is routed to the
high-pressure turbine 622 through a first exhaust channel 612. The
exhaust gas passing through the high-pressure turbine 622 is routed
to the low-pressure turbine 642 via a second exhaust channel 618.
In alternative embodiments, the second exhaust channel 618 may also
receive exhaust gas routed via a bypass channel 614 placed between
the inlet and outlet of the high-pressure turbine 622. In some
embodiments, a valve 616 may be placed in the bypass channel 614
for regulating the amount of bypassed exhaust gas. The
high-pressure turbine 622 is driven to rotate by exhaust gas
supplied from the first exhaust channel 612. The low-pressure
turbine 642 is driven to rotate by the exhaust gas supplied from
the second exhaust channel 618. The exhaust gas passing through the
low-pressure turbine 642 may be discharged directly to the
environment via a third exhaust channel 658. In alternative
embodiments, the exhaust gas may be re-circulated to the intake
manifold 606 of the engine 602.
[0040] Further referring to FIG. 9, during operation, the
low-pressure turbine 642 drives the low-pressure compressor 644 to
rotate through the low-pressure drive shaft 646. The low-pressure
compressor 644 compresses input air flow received from a first
intake channel 632 and provides intermediate air flow with a
boosted air pressure to a second intake channel 634. The
intermediate air flow is further compressed by the high-pressure
compressor 624 which is driven to rotate by the high-pressure
turbine 622 through the high-pressure drive shaft 626. The
high-pressure compressor 624 provides output air flow with further
boosted air pressure to the intake manifold 606 via a third intake
channel 654. In some embodiments, the intermediate air flow in the
second intake channel 634 may be routed to the third intake channel
654 via a bypass channel 636. In some embodiments, a valve 638 may
be placed in the bypass channel 636 for regulating the amount of
bypassed air flow.
[0041] Further referring to FIG. 9, the low-pressure stage
turbocharger system 620 may include a low-pressure thrust bearing
648. The low-pressure thrust bearing 648 is attached to the
low-pressure drive shaft 646 for supporting axial thrust load 662
applied to the low-pressure thrust bearing 648. In one
implementation, the axial thrust load 662 is a net thrust load
which may include a compressor back-surface thrust load 664
component generated due to the leakage air flow at the back surface
643 of the low-pressure compressor 644. In one implementation, the
low-pressure compressor 644 is configured with one or more flow
restriction structures 649 at the back surface 643 of the
low-pressure compressor 624. The one or more flow restriction
structures 649 are similar to the flow restriction structures 224
as described above with reference to FIGS. 1-3. During rotational
movement of the low-pressure compressor 644, a portion of the
intermediate air flow is prevented from entering into the back
surface 643 of the low-pressure compressor 644, such that the axial
thrust load 664 applied to the low-pressure thrust bearing 648 is
reduced. As a result, over-wearing problems of the low-pressure
thrust bearing 648 can be avoided and/or the life of the
low-pressure thrust bearing 648 can be extended or prolonged.
[0042] Further referring to FIG. 9, in one implementation, the
high-pressure stage turbocharger system 620 may further include a
high-pressure thrust bearing 628. The high-pressure thrust bearing
628 is attached to the high-pressure drive shaft 626 for supporting
the axial thrust load 666 applied to the high-pressure drive shaft
626. In one implementation, the axial thrust load 666 is a net
thrust load which may include a compressor back-surface thrust load
668 component. The net thrust load 666 and the compressor
back-surface thrust load 668 point to the same direction which may
be in parallel to a rotational axis of the high-pressure drive
shaft 626. In the illustrated embodiment, the high-pressure
compressor 624 may be optionally or additionally configured with
one or more flow restriction structures 629. The one or more flow
restriction structures 629 may be similar to the flow restriction
structures 224 that have been described above with reference to
FIGS. 1-3. During rotational movement of the high-pressure
compressor 624, the one or more flow restriction structures 629
function to prevent at least a portion of the output air flow from
entering the back surface 623 of the high-pressure compressor 624.
The reduced amount of leakage air at the back surface 623 of the
high-pressure compressor 624 causes a reduction of the axial thrust
load 668 and the net thrust load 666 applied to the high-pressure
thrust bearing 628. As a result, over-wearing problems of the
high-pressure thrust bearing 628 can be avoided and the life of the
high-pressure thrust bearing 628 can be extended or prolonged.
[0043] In alternative embodiments, the one or more flow restriction
structures 649 provided at the back surface 643 of the low-pressure
compressor 644 and/or the one or more flow restriction structures
629 provided at the back surface 623 of the high-pressure
compressor 624 can be further modified for balancing purpose of the
low-pressure compressor 644 and the high-pressure compressor 624
respectively. For example, the one or more flow restriction
structures 629, 649 can be removed with material for balancing.
Furthermore, the one or more flow restriction structure 629, 649
can also be added with material for balancing.
[0044] FIG. 10 illustrates a schematic block diagram of another
two-stage turbocharger system 700 in accordance with an exemplary
embodiment of the present disclosure. The two-stage turbocharger
system 700 is similar to the two-stage turbocharger system 600
described above with reference to FIG. 9. Thus, similar elements
will not be described in more detail in this embodiment. In the
illustrated embodiment, the two-stage turbocharger system 700
further includes a bypass channel 656 which is in flow
communication with the high-pressure compressor 624 and the
low-pressure turbine 642. More specifically, in one embodiment, a
first end 657 of the bypass channel 656 is coupled to the third
intake channel 654 coupled between the high-pressure compressor 624
and the intake manifold 606 of the internal combustion engine 602.
A second end 659 of the bypass channel 656 is coupled to the back
surface 645 of the low-pressure turbine 642. The air flow at the
back surface 645 of the low-pressure turbine 642 generates a
turbine back-surface thrust load 665 which is a thrust load
component of the net thrust load 662. In the illustrated
embodiment, the turbine back-surface thrust load 665 is opposite to
the compressor back-surface thrust load or the net thrust load
662.
[0045] Further referring to FIG. 10, in one implementation, during
operation, the bypass channel 656 diverts a portion of the output
air flow flowing in the third intake channel 654 to the back
surface of the low-pressure turbine 642. More specifically, in the
illustrated embodiment, the diverted air flow comes out from a
combination of the air flow from the high-pressure compressor 624
and the bypass channel 636. In another embodiment, the diverted air
flow may optionally directly come from the immediate output of the
high-pressure compressor 624. The diverted air flow helps to
increase the air pressure at the back surface 645 of the
low-pressure turbine 642 which in turn increases the turbine
back-surface thrust load 665 pointing from the low-pressure
compressor 644 side to the low-pressure turbine 642 side. Because
the net axial thrust load 662 points from the low-pressure turbine
642 side to the low-pressure compressor 644 side, thus, increasing
the thrust load at the back surface 645 of the low-pressure turbine
642 can reduce the net axial thrust load 662 applied to the
low-pressure thrust bearing 648. As a result, over-wearing problems
of the low-pressure thrust bearing 648 can be avoided and/or the
life of the low-pressure thrust bearing 648 can be extended or
prolonged.
[0046] While the invention has been described with reference to
exemplary embodiments, it will be understood by those skilled in
the art that various changes may be made and equivalents may be
substituted for elements thereof without departing from the scope
of the invention. Furthermore, the skilled artisan will recognize
the interchangeability of various features from different
embodiments. Similarly, the various method steps and features
described, as well as other known equivalents for each such methods
and feature, can be mixed and matched by one of ordinary skill in
this art to construct additional assemblies and techniques in
accordance with principles of this disclosure. In addition, many
modifications may be made to adapt a particular situation or
material to the teachings of the invention without departing from
the essential scope thereof. Therefore, it is intended that the
invention not be limited to the particular embodiment disclosed as
the best mode contemplated for carrying out this invention, but
that the invention will include all embodiments falling within the
scope of the appended claims.
* * * * *