FIELD OF THE INVENTION
[0001] The present disclosure relates generally to turbochargers of work vehicles
and, more particularly, to heat shields for use within turbochargers that reduce heat
transfer and reduce thermomechanical fatigue.
BACKGROUND OF THE INVENTION
[0002] Typically, work vehicles, such as tractors and other agricultural vehicles,
include an exhaust treatment system for controlling engine emissions. As is generally
understood, exhaust treatment systems for work vehicles often include a diesel
oxidation catalyst (DOC) system in fluid communication with a selective catalytic
reduction (SCR) system. The DOC system is generally configured to oxidize carbon
monoxide and unburnt hydrocarbons contained within the engine exhaust and may
include a mixing chamber for mixing an exhaust reductant, such as a diesel exhaust
fluid (DEF) or any other suitable urea-based fluid, into the engine exhaust. For
instance, the exhaust reductant is often pumped from a reductant tank mounted on
and/or within the vehicle and injected into the mixing chamber to mix the reductant
with the engine exhaust. The resulting mixture may then be supplied to the SCR
system to allow the reductant to be reacted with a catalyst in order to reduce the
amount of nitrogen oxide (NOx) emissions contained within the engine exhaust.
[0003] In some exhaust treatment systems, some exhaust gas is recirculated back
into an intake of the engine to reduce combustion temperatures within the engine,
which reduces the amount of NOx emitted. To recirculate the exhaust gas, an exhaust
gas recirculation (EGR) valve is connected between an exhaust inlet (e.g., of an
exhaust manifold coupled to an engine exhaust outlet of the engine) and the intake of
the engine. In some instances, a turbocharger is provided to increase the efficiency of
the work vehicle. More particularly, the turbocharger includes a turbine and a
compressor, where the turbine is driven by the pressure of the engine exhaust, and
where rotation of the turbine, in turn, drives a compressor that compresses air (new
and/or recirculated) being fed into the intake of the engine. Bearings are present
within a bearing housing between the turbine and compressor, where the bearings
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support rotation of a shaft rotatably coupling the turbine to the compressor. However,
heat transfer from the turbine to the bearing housing causes the viscosity of
lubricating oil to decrease such that the oil mixing with exhaust gases allows carbon
deposits to start to form on the bearings within the bearing housing.
[0004] Accordingly, a heat shield between a turbine and a bearing housing within
a turbocharger would be welcomed in the technology.
BRIEF DESCRIPTION OF THE INVENTION
[0005] Aspects and advantages of the invention will be set forth in part in the
following description, or may be obvious from the description, or may be learned
through practice of the invention.
[0006] In one aspect, the present subject matter is directed to a turbocharger for a
work vehicle. The turbocharger may include a turbine having a turbine rotor
configured to rotate about a rotor axis when engine exhaust gas flows across the
turbine rotor. The turbocharger may further include a compressor having a
compressor rotor configured to rotate to compress intake air to be combusted by an
engine. Further, the turbocharger may include a shaft rotatably coupled to the turbine
rotor and to the compressor rotor such that rotation of the turbine rotor causes rotation
of the compressor rotor. Moreover, the turbocharger may include a plurality of
bearings supported within a bearing housing, where each of the plurality of bearings
rotatably supports the shaft for rotation about the rotor axis. Additionally, the
turbocharger may include a heat shield disposed between at least a portion of the
bearing housing and the turbine along the rotor axis. Particularly, the heat shield may
extend between a first axial end and a second axial end along the rotor axis, with the
second axial end being closer to the turbine rotor than the first axial end. The heat
shield may define a first opening at the first axial end and a second opening at the
second axial end. The heat shield may have a collar extending from the second
opening towards the first axial end, where the shaft extends through the collar.
[0007] In another aspect, the present subject matter is directed to a work vehicle.
The work vehicle may include an engine having an engine air intake and an engine
exhaust outlet, where intake air is supplied to the engine for combustion through the
engine air intake and where engine exhaust gas exits the engine through the engine
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exhaust outlet. The work vehicle may further include a turbine having a turbine rotor
configured to rotate about a rotor axis when engine exhaust gas flows across the
turbine rotor, a compressor having a compressor rotor configured to rotate to
compress intake air to be combusted by the engine, and a shaft rotatably coupled to
the turbine rotor and to the compressor rotor such that rotation of the turbine rotor
causes rotation of the compressor rotor. Moreover, the work vehicle may include a
plurality of bearings supported within a bearing housing, where each of the plurality
of bearings rotatably support the shaft for rotation about the rotor axis. Additionally,
the work vehicle may include a heat shield disposed between at least a portion of the
bearing housing and the turbine along the rotor axis. Particularly, the heat shield may
extend between a first axial end and a second axial end along the rotor axis, with the
second axial end being closer to the turbine rotor than the first axial end. More
particularly, the heat shield may define a first opening at the first axial end and a
second opening at the second axial end. The heat shield may particularly include a
collar extending from the second opening towards the first axial end, where the shaft
extends through the collar.
[0008] These and other features, aspects and advantages of the present invention
will become better understood with reference to the following description and
appended claims. The accompanying drawings, which are incorporated in and
constitute a part of this specification, illustrate embodiments of the invention and,
together with the description, serve to explain the principles of the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
[0009] A full and enabling disclosure of the present invention, including the best
mode thereof, directed to one of ordinary skill in the art, is set forth in the
specification, which makes reference to the appended figures, in which:
[0010] FIG. 1 illustrates a side view of one embodiment of a work vehicle in
accordance with aspects of the present subject matter;
[0011] FIG. 2 illustrates a schematic view of one embodiment of an exhaust
treatment system suitable for use with a work vehicle in accordance with aspects of
the present subject matter;
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[0012] FIG. 3 illustrates a partial section view of one embodiment of a
turbocharger suitable for use within an exhaust treatment system of a work vehicle in
accordance with aspects of the present subject matter;
[0013] FIG. 4 illustrates an end view of a heat shield for use within a turbocharger
of a work vehicle in accordance with aspects of the present subject matter; and
[0014] FIG. 5 illustrates a cross-sectional view of the heat shield of FIG. 4 taken
with respect to section line 5-5’ in accordance with aspects of the present subject
matter.
[0015] Repeat use of reference characters in the present specification and
drawings is intended to represent the same or analogous features or elements of the
present technology.
DETAILED DESCRIPTION OF THE INVENTION
[0016] Reference now will be made in detail to embodiments of the invention,
one or more examples of which are illustrated in the drawings. Each example is
provided by way of explanation of the invention, not limitation of the invention. In
fact, it will be apparent to those skilled in the art that various modifications and
variations can be made in the present invention without departing from the scope or
spirit of the invention. For instance, features illustrated or described as part of one
embodiment can be used with another embodiment to yield a still further
embodiment. Thus, it is intended that the present invention covers such modifications
and variations as come within the scope of the appended claims and their equivalents.
[0017] In general, the present subject matter is directed to a heat shield for a
turbocharger of a work vehicle, particularly an improved heat shield between a
turbine and a bearing housing of a turbocharger. For instance, a turbocharger may
include a turbine and a compressor. The turbine is configured to receive engine
exhaust gas from an outlet of an engine, where the exhaust gas causes a turbine rotor
of the turbine to rotate about a rotor axis. Rotation of the turbine rotor causes rotation
of a shaft rotatably coupled to the turbine rotor, where the shaft is further rotatably
coupled to a compressor rotor of the compressor. As such, rotation of the turbine
rotor causes rotation of the compressor rotor about the rotor axis, which compresses
intake air directed to an intake of the engine. The shaft is supported for rotation about
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the rotor axis by bearings within a bearing housing. A heat shield is configured to
reduce heat exchanged between the turbine and the bearing housing. More
particularly, the improved heat shield may have an internal collar that extends along
the shaft to reduce heat transferred from the turbine to the bearing housing, and thus,
reduce or prevent carbon deposits forming on the bearings within the bearing housing.
Further, in some embodiments, the improved heat shield may be made of a fiber
reinforced ceramic composite matrix (FRCMC) which significantly reduces heat
transfer compared to traditional heat shield materials such as steel. Additionally, in
one embodiment, the improved heat shield may have ribs or steps in the profile to
reduce thermo-mechanical fatigue. For instance, the ribs may help reduce flexing of
the heat shield along the axial direction, extending parallel to the rotor axis, during
changes in temperature of the heat shield.
[0018] Referring now to the drawings, FIG. 1 illustrates a side view of one
embodiment of a work vehicle 100. As shown, the work vehicle 100 is configured as
an agricultural tractor. However, in other embodiments, the work vehicle 100 may be
configured as any other suitable work vehicle known in the art, such as various other
agricultural vehicles, earth-moving vehicles, road vehicles, all-terrain vehicles, offroad vehicles, loaders, and/or the like.
[0019] As shown in FIG. 1, the work vehicle 100 includes a pair of front wheels
102, a pair of rear wheels 104, and a chassis 106 coupled to and supported by the
wheels 102, 104. An operator’s cab 108 may be supported by a portion of the chassis
106 and may house various control devices 110, 112 (e.g., levers, pedals, control
panels and/or the like) for permitting an operator to control the operation of the work
vehicle 100. Additionally, the work vehicle 100 may include an engine 114 (e.g., a
diesel engine) and a transmission 116 mounted on the chassis 106. The transmission
116 may be operably coupled to the engine 114 and may provide variably adjusted
gear ratios for transferring engine power to the wheels 104 via a differential 118.
[0020] Moreover, the work vehicle 100 may also include an exhaust treatment
system 150 for reducing the amount of emissions contained within the exhaust from
the engine 114. For instance, engine exhaust gas expelled from the engine 114 may
be directed through the exhaust treatment system 150 to allow the levels of nitrogen
oxide (NOx) emissions contained within the exhaust to be reduced significantly. The
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cleaned or treated exhaust gases may then be expelled from the exhaust treatment
system 150 into the surrounding environment via an exhaust pipe 120 of the work
vehicle 100.
[0021] It should be appreciated that the configuration of the work vehicle 100
described above and shown in FIG. 1 is provided only to place the present subject
matter in an exemplary field of use. Thus, it should be appreciated that the present
subject matter may be readily adaptable to any manner of work vehicle configuration.
For example, in an alternative embodiment, a separate frame or chassis may be
provided to which the engine 114, transmission 116, and differential 118 are coupled,
a configuration common in smaller tractors. Still other configurations may use an
articulated chassis to steer the work vehicle 100, or rely on tracks in lieu of the wheels
102, 104. Additionally, although not shown, the work vehicle 100 may also be
configured to be operably coupled to any suitable type of work implement, such as a
trailer, spray boom, manure tank, feed grinder, plow and/or the like.
[0022] Referring now to FIG. 2, a schematic diagram of one embodiment of an
exhaust treatment system 150 suitable for use with a work vehicle 100 is illustrated in
accordance with aspects of the present subject matter. As represented in FIG. 2,
engine 114 includes an engine air intake EAI through which the engine 114 is
configured to receive air to be combusted and an engine exhaust outlet EEO through
which the engine 114 is configured to exhaust combusted exhaust gas. The exhaust
treatment system 150 has a plurality of elements coupled to the engine exhaust outlet
EEO (hereinafter referred to as “outlet EEO”). For instance, the exhaust treatment
system 150 includes a diesel oxidation catalyst (DOC) system 154, an optional diesel
particulate filter (DPF) 156, and a selective catalytic reduction (SCR) system 158.
The exhaust treatment system 150 additionally includes a turbocharger 152 coupled to
the outlet EEO, upstream of the DOC system 154. The turbocharger 152 includes a
turbine 152T and a compressor 152C.
[0023] During operation of the work vehicle 100, exhaust gas expelled from the
outlet EEO of the engine 114 is directed to the turbine 152T, which causes the turbine
152T to rotate and rotatably drive the compressor 152C. The exhaust gas exiting the
turbine 152T is then received by the DOC system 154. As is generally understood,
the DOC system 154 is configured to reduce the levels of carbon monoxide and
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hydrocarbons present in the engine exhaust. For example, the DOC system 154 may
include a canister or chamber receiving engine exhaust. In some embodiments, the
chamber is configured to use excess oxygen in the engine exhaust and, optionally,
ceramics, metals (e.g., platinum, palladium, etc.), or other suitable catalysts to
catalyze the conversion of carbon monoxide and hydrocarbons in the exhaust into
water and carbon dioxide. Generally, the amount of carbon monoxide and
hydrocarbons in the catalyzed exhaust flow after passing through the chamber is
reduced as compared to the engine exhaust initially discharged from the engine 114.
[0024] A reductant injector nozzle (not shown) is provided to allow an exhaust
reductant, such as a diesel exhaust fluid (DEF) or any other suitable urea-based fluid,
to be injected into the stream of exhaust gases flowing through or from the chamber
of the DOC system 154. For instance, the reductant injector nozzle may be fluidly
coupled to a source of exhaust reductant (e.g., storage tank) via a hose or other fluid
coupling to allow liquid exhaust reductant to be supplied to the nozzle. In one
embodiment, the nozzle may be positioned within the DOC system 154. The exhaust
and the exhaust reductant mix as they flow through the DOC system 154. The
exhaust/reductant mixture is then directed out of an outlet of the DOC system 154 for
receipt by the DPF 156, when present, downstream of the DOC system 154 and
upstream of the SCR system 158. The DPF 156 collects and filters out excess
particulate or soot in the treated exhaust gas from the DOC system 154 that was not
oxidized by the DOC system 154. As will be described below in greater detail, the
DPF 156 will oxidize the collected particulates when the exhaust temperatures are
sufficiently high. The filtered exhaust expelled from the outlet of the DPF 156 is
directed to an inlet of the SCR system 158. Within the SCR system 158, the mixture
of exhaust/reductant is reacted with a catalyst to generate a treated exhaust flow in
which the amount of harmful or undesirable gas emissions has been reduced as
compared to the engine exhaust initially discharged from the engine 114. The treated
exhaust flow is then expelled from an outlet of the SCR system 158 and is discharged
into the atmosphere (e.g., via the exhaust pipe 120 forming part of or coupled to the
outlet of the SCR system 158).
[0025] Additionally, the exhaust treatment system 150 may include an exhaust
gas recirculation (EGR) circuit 160 configured to selectively recirculate at least a
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portion of exhaust gas from the outlet EEO to the engine air intake EAI to reduce the
combustion temperature within the engine 114, which reduces NOx emissions and
improves fuel economy. More particularly, the EGR circuit 160 may include an EGR
housing 162, which may include heat exchange components, where an inlet of the
EGR housing 162 is coupled to the outlet EEO of the engine 114 and where an outlet
of the EGR housing 162 is coupled to the engine air intake EAI of the engine 114
(e.g., indirectly via the compressor 152C). The EGR circuit 160 may further include
an EGR valve 164 configured to selectively allow the exhaust gas to be passed
through the EGR circuit 160 to the engine air intake EAI (e.g., to the compressor
152C). For instance, the EGR valve 164 is controllable to move between an opened
position and a closed position, where exhaust gas is allowed to pass through the EGR
valve 164 and the EGR housing 162 to the engine air intake EAI when the EGR valve
164 is in the opened position, and where exhaust gas is blocked or prevented from
flowing through the EGR valve 164 to the engine air intake EAI when the EGR valve
164 is in the closed position. In some instances, the EGR valve 164 is downstream of
the EGR housing 162, between the EGR housing 162 and the engine air intake EA1.
However, in other embodiments, the EGR valve 164 may be part of the EGR housing
162 or may be upstream of the EGR housing 162, between the outlet EEO and the
EGR housing 162. In some instances, the EGR circuit 160 may further include an
EGR sensor (not shown) configured to generate data indicative of the position of the
EGR valve 164 between the opened and closed positions.
[0026] Ambient air received through the ambient air inlet AAI and any
recirculated air from the EGR circuit 160 are directed into the compressor 152C.
Rotation of the compressor 152C compresses the received mixture of ambient and/or
recirculated air which is then supplied to the intake EAI of the engine 114. By
compressing the air supplied to be combusted within the engine 114, the overall
amount of air supplied to the engine 114 is increased, which improves the efficiency
of the combustion process within the engine 114, and thus, improves the efficiency of
the work vehicle 100.
[0027] It should be appreciated that, while the EGR circuit 160 and the turbine
152T are illustrated as being separately coupled to the outlet EEO of the engine 114 to
receive exhaust gas, an exhaust manifold may be provided, where the exhaust
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manifold has an exhaust inlet coupled to the engine exhaust outlet EEO and an
exhaust manifold outlet coupled to the EGR circuit 160 and the turbine 152T.
[0028] Referring now to FIG. 3, a partial section view of one embodiment of a
turbocharger (e.g., the turbocharger 152) suitable for use within an exhaust treatment
system (e.g., the exhaust treatment system 150) of a work vehicle (e.g., the work
vehicle 100) in accordance with aspects of the present subject matter. As particularly
shown in FIG. 3, the turbine 152T has a housing 153 defining one or more turbine
inlet passages 202 configured to receive the engine exhaust gas from the engine 114
(FIG. 2). The engine exhaust gas is then directed within the housing 153 from the
inlet passage(s) 202 to a turbine rotor 204. The turbine rotor 204 is rotatably mounted
within the turbine housing 153 such that the turbine rotor 204 is rotatable about a
rotor axis 204A. The turbine rotor 204 has a plurality of fins 204F which are pushed
by the exhaust gas to rotate the turbine rotor 204 about the rotor axis 204A. The
exhaust gas may then be directed out of the turbine 152T through the turbine outlet
206 defined in the turbine housing 153, downstream of the turbine rotor 204, and, for
example, to the DOC system 154 (FIG. 2).
[0029] Similarly, the compressor 152C has a compressor housing 155 defining
one or more compressor inlet passages 208 through which intake air (e.g., a
combination of recirculated and/or ambient air) is drawn in and directed towards a
compressor rotor 210. A compressor rotor is rotatably mounted within the
compressor housing 155 such that the compressor rotor 210 is also rotatable about the
rotor axis 204A. The compressor rotor 210 has a plurality of fins 210F. As the
compressor rotor 210 rotates, the fins 210F help draw the intake air into the
compressor housing 155 and subsequently push or direct the intake air into lobes 212
of the compressor housing 155, which compresses the intake air. The compressed air
is then directed out of the compressor 152C through the compressor outlet 214
defined in the compressor housing 155 to the engine air intake EAI.
[0030] A shaft 216 rotatably couples the turbine rotor 204 to the compressor rotor
210. For instance, the shaft 216 is rotatably coupled proximate a first end to the
center of the turbine rotor 204 and proximate an opposite, second end to a center of a
compressor rotor 210 of the compressor 152C. In some instances, the shaft 216
extends through the entire axial length of the turbine rotor 204, through a radial center
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of the turbine rotor 204, such that the first end of shaft 216 is rotatably coupled at an
axial center of the turbine rotor 204 furthest from the compressor 152C. Similarly, in
one instance, the shaft 216 extends through the entire axial length of the compressor
rotor 210, through a radial center of the compressor rotor 210, such that the second
end of the shaft is rotatably coupled at an axial end of the compressor rotor 210
furthest from the turbine 152T. However, it should be appreciated that the shaft 216
may be rotatably coupled to the turbine rotor 204 and the compressor rotor 210 in any
other suitable manner. Generally, rotation of the turbine rotor 204 causes rotation of
the shaft 216, which in turn causes rotation of the compressor rotor 210. In some
embodiments, the rotation of the compressor rotor 210 has a 1:1 ratio with the rotation
of the turbine rotor 210. The shaft 216 is supported for rotation about the rotor axis
204A by bearings 218 (e.g., ball bearings within a bearing race) within a bearing
housing 220 of the turbocharger 152. During operation of the engine 114, the
bearings 218 are lubricated and cooled by a lubricating oil. However, as the turbine
152T heats up from the exhaust gas, heat begins to conductively transfer from the
turbine 152T (e.g., the turbine housing 153) to the bearing housing 220. If the
temperature within the bearing housing 220 becomes excessively high, the lubricating
oil inside the bearing housing 220 may begin to carbonize which may cause carbon
deposits to build up on the bearings 218, which degrades the performance of the
bearings 218 and, thus, the turbocharger 152 as a whole.
[0031] Thus, in accordance with aspects of the present subject matter, a heat
shield 222 is provided between the bearing housing 220 and the turbine housing 153.
Particularly, the heat shield 222 may at least partially surround the axial end of the
bearing housing 220 proximate the turbine 152T. In some instances, the bearing
housing 220 is at least partially received within the turbine housing 153. In one
embodiment, the bearing housing 220 separates the turbine 152T from the compressor
152C along the rotor axis 204. The shaft 216 may be configured to extend through a
central opening of the heat shield 222 to couple to the turbine rotor 204. The heat
shield 222 is preferably made of a material with low thermal conductivity. For
instance, the heat shield 222 is preferably made of a fiber reinforced ceramic
composite matrix (FRCMC) material. Generally, ceramic fibers enhance ductility and
minimize thermal conductivity. Further, FRCMC materials reinforced with long
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continuous fibers exhibit improved tolerance to severe thermomechanical and
environmental exposures. Examples of suitable FRCMC materials includes ceramic
sheets made by lamination of intercalated minerals such as mica, vermiculite and
graphite and fibers, sheets made by compression, weaving, or suitable ordering of
glass and other ceramic fibers such as zirconia fiber. Suitable properties of an
example FRCMC material includes a Youngs modulus of about 375 gigapascals
(GPa), a tensile strength of about 275 megapascals (MPa), a Poissons ratio of about
0.22, a thermal conductivity of about 35 Watts per meter-Kelvin (W/mK), and a
thermal expansion of about 0.08. It should be appreciated that “about” for the values
given for the various properties is intended to mean within a range +/-10% of the
given value. However, it should be appreciated that any other suitable material with
similar properties may instead be used.
[0032] The heat shield 222 may be shaped to further reduce heat transfer from the
turbine 152T to the bearing housing 220 and to improve resistance to
thermomechanical fatigue. For instance, turning now to FIGS. 4 and 5, various views
of a heat shield (e.g., the heat shield 222) for use within a turbocharger (e.g.,
turbocharger 152) of a work vehicle (e.g., the work vehicle 100) are illustrated in
accordance with aspects of the present subject matter. More particularly, FIG. 4
illustrates an end view of a heat shield (e.g., the heat shield 222) and FIG. 5 illustrates
a cross-sectional view of the heat shield of FIG. 4 taken with respect to section line 5-
5’.]

WE CLAIM:
1. A turbocharger for a work vehicle, the turbocharger comprising:
a turbine having a turbine rotor configured to rotate about a rotor axis when
engine exhaust gas flows across the turbine rotor;
a compressor having a compressor rotor configured to rotate to compress
intake air to be combusted by an engine;
a shaft rotatably coupled to the turbine rotor and to the compressor rotor such
that rotation of the turbine rotor causes rotation of the compressor rotor;
a plurality of bearings supported within a bearing housing, each of the
plurality of bearings rotatably supporting the shaft for rotation about the rotor axis;
and
a heat shield disposed between at least a portion of the bearing housing and the
turbine along the rotor axis, the heat shield extending between a first axial end and a
second axial end along the rotor axis, the second axial end being closer to the turbine
rotor than the first axial end, the heat shield defining a first opening at the first axial
end and a second opening at the second axial end, the heat shield having a collar
extending from the second opening towards the first axial end, the shaft extending
through the collar.
2. The turbocharger as claimed in claim 1, wherein the heat shield defines
one or more ribs extending around a circumference of the heat shield, each of the one
or more ribs having a stepped profile defining an axial rib portion extending parallel
to the rotor axis.
3. The turbocharger as claimed in claim 2, wherein the axial rib portion
of a first rib of the one or more ribs extends from the second axial end toward the first
axial end.
4. The turbocharger as claimed in claim 2, wherein the axial rib portions
of the one or more ribs are directly axially adjacent to each other, the axial rib
portions of the one or more ribs extending from the second axial end by a first axial
distance, and
wherein the collar extends from the second axial end towards the first axial
end along a second axial distance, the second axial distance being greater than the
first axial distance.
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5. The turbocharger as claimed in claim 1, wherein an axial end of the
bearing housing closest to the turbine rotor is configured to be at least partially
received within the heat shield via the first opening, the axial end of the bearing
housing closest to the turbine rotor being configured to contact an axial end of the
collar closest to the first axial end of the heat shield.
6. The turbocharger as claimed in claim 5, wherein a collar flange
extends radially outwardly from the axial end of the collar closest to the first axial end
of the heat shield, the axial end of the bearing housing closest to the turbine rotor
being configured to contact the collar flange.
7. The turbocharger as claimed in claim 1, wherein the collar extends
around a circumference of the second opening.
8. The turbocharger as claimed in claim 1, wherein the heat shield is
comprised of a fiber reinforced ceramic composite matrix (FRCMC) material.
9. The turbocharger as claimed in claim 1, wherein the compressor rotor
is configured to rotate about the rotor axis.
10. The turbocharger as claimed in claim 1, wherein the heat shield has a
flange extending radially outwardly at the first axial end, the flange being received
between the bearing housing and the turbine.
11. A work vehicle, comprising:
an engine having an engine air intake and an engine exhaust outlet, intake air
being supplied to the engine for combustion through the engine air intake and engine
exhaust gas exiting the engine through the engine exhaust outlet;
a turbine having a turbine rotor configured to rotate about a rotor axis when
engine exhaust gas flows across the turbine rotor;
a compressor having a compressor rotor configured to rotate to compress
intake air to be combusted by the engine;
a shaft rotatably coupled to the turbine rotor and to the compressor rotor such
that rotation of the turbine rotor causes rotation of the compressor rotor;
a plurality of bearings supported within a bearing housing, each of the
plurality of bearings rotatably supporting the shaft for rotation about the rotor axis;
and
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a heat shield disposed between at least a portion of the bearing housing and the
turbine along the rotor axis, the heat shield extending between a first axial end and a
second axial end along the rotor axis, the second axial end being closer to the turbine
rotor than the first axial end, the heat shield defining a first opening at the first axial
end and a second opening at the second axial end, the heat shield having a collar
extending from the second opening towards the first axial end, the shaft extending
through the collar.
12. The work vehicle as claimed in claim 11, wherein the heat shield
defines one or more ribs extending around a circumference of the heat shield, each of
the one or more ribs having a stepped profile defining an axial rib portion extending
parallel to the rotor axis.
13. The work vehicle as claimed in claim 12, wherein the axial rib portion
of a first rib of the one or more ribs extends from the second axial end toward the first
axial end.
14. The work vehicle as claimed in claim 12, wherein the axial rib portions
of the one or more ribs are directly axially adjacent to each other, the axial rib
portions of the one or more ribs extending from the second axial end by a first axial
distance, and
wherein the collar extends from the second axial end towards the first axial
end along a second axial distance, the second axial distance being greater than the
first axial distance.
15. The work vehicle as claimed in claim 11, wherein an axial end of the
bearing housing closest to the turbine rotor is configured to be at least partially
received within the heat shield via the first opening, the axial end of the bearing
housing closest to the turbine rotor being configured to contact an axial end of the
collar closest to the first axial end of the heat shield.
16. The work vehicle as claimed in claim 15, wherein a collar flange
extends radially outwardly from the axial end of the collar closest to the first axial end
of the heat shield, the axial end of the bearing housing closest to the turbine rotor
being configured to contact the collar flange.
17. The work vehicle as claimed in claim 11, wherein the heat shield is
comprised of a fiber reinforced ceramic composite matrix (FRCMC) material.
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18. The work vehicle as claimed in claim 11, wherein the turbine further
comprises a turbine housing, the turbine housing defining a turbine inlet passage and a
turbine outlet, the turbine inlet passage being coupled to the engine exhaust outlet,
and the turbine rotor being positioned within the turbine housing between the turbine
inlet passage and the turbine outlet, and
wherein the compressor further comprises a compressor housing, the
compressor housing defining a compressor inlet passage and a compressor outlet, the
compressor outlet being coupled to the engine air intake, the compressor rotor being
positioned within the compressor housing between the compressor inlet passage and
the compressor outlet.
19. The work vehicle as claimed in claim 11, wherein the engine is a diesel
engine.