U.S. patent application number 13/749893 was filed with the patent office on 2014-07-31 for turbocharger, system, and method for draining fluid from a turbocharger.
This patent application is currently assigned to GENERAL ELECTRIC COMPANY. The applicant listed for this patent is GENERAL ELECTRIC COMPANY. Invention is credited to Matthew John MALONE, Harsha VARDHANA.
Application Number | 20140208740 13/749893 |
Document ID | / |
Family ID | 51163669 |
Filed Date | 2014-07-31 |
United States Patent
Application |
20140208740 |
Kind Code |
A1 |
MALONE; Matthew John ; et
al. |
July 31, 2014 |
TURBOCHARGER, SYSTEM, AND METHOD FOR DRAINING FLUID FROM A
TURBOCHARGER
Abstract
Various methods and systems are provided for removing fluid from
a turbocharger turbine. In one example, a turbocharger comprises a
turbine including a casing housing a rotor, a drain passage coupled
to the casing, and an air jet coupled to the drain passage, the air
jet supplying intake air from a high-pressure compressor outlet to
the drain passage.
Inventors: |
MALONE; Matthew John;
(Lawrence Park, PA) ; VARDHANA; Harsha;
(Bangalore, IN) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
GENERAL ELECTRIC COMPANY |
Schenectady |
NY |
US |
|
|
Assignee: |
GENERAL ELECTRIC COMPANY
Schenectady
NY
|
Family ID: |
51163669 |
Appl. No.: |
13/749893 |
Filed: |
January 25, 2013 |
Current U.S.
Class: |
60/605.1 ;
415/182.1; 60/273 |
Current CPC
Class: |
F01D 25/32 20130101;
F02B 37/013 20130101; F16N 31/00 20130101; Y02T 10/12 20130101;
F02B 37/18 20130101; F05D 2220/40 20130101; Y02T 10/144 20130101;
F02B 37/16 20130101 |
Class at
Publication: |
60/605.1 ;
415/182.1; 60/273 |
International
Class: |
F01D 25/32 20060101
F01D025/32 |
Claims
1. A turbocharger, comprising: a turbine including a casing housing
a rotor; a drain passage coupled to the casing; and an air jet
coupled to the drain passage, the air jet configured to supply
intake air from a high-pressure compressor outlet to the drain
passage.
2. The turbocharger of claim 1, wherein the turbine is a
low-pressure turbine located downstream of a high-pressure turbine
in an exhaust flow path.
3. The turbocharger of claim 1, wherein the turbine is mechanically
coupled to a low-pressure compressor located upstream of the
high-pressure compressor in an intake air flow path.
4. The turbocharger of claim 1, wherein the turbine casing is open
to atmosphere in at least one location.
5. The turbocharger of claim 1, wherein the drain passage is
coupled to atmosphere.
6. The turbocharger of claim 1, wherein the drain passage is
coupled to a vertical low point of the casing.
7. The turbocharger of claim 1, wherein the turbine is located
downstream of an engine, and wherein the drain passage is
configured to passively drain fluid from the casing when the engine
is not operating.
8. The turbocharger of claim 7, wherein the drain passage is
configured to seal a flow of exhaust gas from the casing to
atmosphere when the engine is operating.
9. The turbocharger of claim 1, wherein the turbocharger is
installed in a vehicle, and wherein a pressure of the intake air
from the high-pressure compressor outlet is greater than
atmospheric pressure during engine operation.
10. A system, comprising: an engine; a first turbocharger including
a first turbine mechanically coupled to a first compressor; a
second turbocharger including a second turbine located downstream
of the first turbine in an exhaust flow path, the second turbine
mechanically coupled to a second compressor, the second compressor
located upstream of the first compressor in an intake flow path; a
drain passage coupling the second turbine to atmosphere; and a
compressed air line coupling the drain passage to an outlet of the
first compressor.
11. The system of claim 10, wherein the drain passage is configured
to passively drain fluid from the second turbine when the engine is
not operating.
12. The system of claim 10, wherein the drain passage is configured
to seal a flow of exhaust gas from the second turbine to atmosphere
when the engine is operating.
13. The system of claim 12, wherein, when the engine is operating,
compressed intake air flows from the outlet of the first compressor
to the drain passage through the compressed air line in order to
seal the flow of exhaust gas.
14. A vehicle comprising: a vehicle platform; and the system of
claim 10 attached to the vehicle platform.
15. A method, comprising: when a pressure of intake air at a
high-pressure compressor outlet is greater than a pressure of
exhaust gas downstream of a low-pressure turbine, sealing a flow of
exhaust gas from the low-pressure turbine through a drain passage
to atmosphere; and when the pressure of intake air at the
high-pressure compressor outlet is not greater than the pressure of
exhaust gas downstream of the low-pressure turbine, draining fluid
from the low-pressure turbine through the drain passage.
16. The method of claim 15, wherein sealing the flow of exhaust gas
from the low-pressure turbine through the drain passage to
atmosphere further comprises directing air from the high-pressure
compressor outlet to the drain passage.
17. The method of claim 15, wherein the pressure of intake air at
the high-pressure compressor outlet being greater than the pressure
of exhaust gas downstream of the low-pressure turbine occurs during
engine operation.
18. The method of claim 15, wherein the pressure of intake air at
the high-pressure compressor outlet being no greater than the
pressure of exhaust gas downstream of the low-pressure turbine
occurs during engine off conditions.
19. The method of claim 15, further comprising compressing the
intake air with the high-pressure compressor, the high-pressure
compressor driven by a high-pressure turbine.
20. The method of claim 15, further comprising compressing the
intake air with the high-pressure compressor, the high-pressure
compressor driven by at least one of a motor or an engine.
Description
FIELD
[0001] Embodiments of the subject matter disclosed herein relate to
a turbocharger for an internal combustion engine.
BACKGROUND
[0002] Turbochargers are devices used to increase the power output
of an engine by compressing air into the engine with a compressor
driven by a turbine that harvests energy from the hot engine
exhaust gases. Over time, as turbocharged engines operate, some of
the additives in the lubricating oil are deposited on the
turbocharger turbine nozzle ring and turbine wheel blades. These
deposits tend to be readily dissolved in rainwater. Many
turbocharged engines, such as those used in locomotives, are
designed with a simple stack or relatively open muffler directly
above the turbocharger turbine. Thus, if the engine is shut down
and no gas is flowing through the turbine, rainwater can accumulate
around the stationary turbine parts. If the water level is high
enough and the water is undisturbed for a period of time, the
deposits on the turbine blades partially or completely submerged in
the water can be locally dissolved, leading to a significant rotor
imbalance once the engine is restarted.
BRIEF DESCRIPTION
[0003] In one embodiment, a turbocharger comprises a turbine
including a casing housing a rotor, a drain passage coupled to the
casing, and an air jet coupled to the drain passage. The air jet is
configured to supply intake air from a high-pressure compressor
outlet to the drain passage.
[0004] In this way, according to one aspect of the invention, water
that has accumulated in the turbine casing may be passively drained
via the drain passage. To prevent leakage of exhaust gas out of the
drain passage, compressed intake air may be routed to the drain
passage, sealing the drain passage when the pressure of the
compressed intake air is greater than the pressure of the exhaust
in the turbine. This may occur, for example, during engine
operation when intake air is directed through the high-pressure
compressor. Then, when compressed intake air is not available (such
as when the engine is off), the water may drain out of the
turbine.
[0005] It should be understood that the brief description above is
provided to introduce in simplified form a selection of concepts
that are further described in the detailed description. It is not
meant to identify key or essential features of the claimed subject
matter, the scope of which is defined uniquely by the claims that
follow the detailed description. Furthermore, the claimed subject
matter is not limited to implementations that solve any
disadvantages noted above or in any part of this disclosure.
BRIEF DESCRIPTION OF THE DRAWINGS
[0006] The present invention will be better understood from reading
the following description of non-limiting embodiments, with
reference to the attached drawings, wherein below:
[0007] FIG. 1 shows a schematic diagram of a rail vehicle with an
engine according to an embodiment of the invention.
[0008] FIG. 2 shows a cross-sectional view of a turbocharger
according to an embodiment of the invention.
[0009] FIG. 3 shows a flow chart illustrating a method for removing
accumulated fluid from a turbocharger according to an embodiment of
the invention.
DETAILED DESCRIPTION
[0010] The following description relates to various embodiments of
a turbocharger including a drain passage coupled to the casing of
the turbocharger. The drain passage may passively drain accumulated
water out of the turbine when the engine is not operating. However,
during engine operation, to prevent the drain passage from
providing a path for exhaust gas to leak out of the turbine and to
the vehicle cabin (for example), the drain passage may be coupled
to the outlet of a compressor. During engine operation, the
compressor may generate air of higher pressure than the exhaust
downstream of the turbine. This high pressure air flows to the
drain passage and prevents flow of exhaust gas out of the turbine
casing. The drain passage may be coupled to the turbine of a
low-pressure turbocharger and the compressed intake air may be
directed to the drain passage from a compressor outlet of a
high-pressure turbocharger. The intake air from the outlet of the
high-pressure compressor may be of pressure greater than
atmospheric at substantially all engine operating conditions. For
example, the intake air at the high-pressure compressor outlet may
greater than atmospheric at each throttle position (e.g., for some
rail vehicles, notched throttle position), including idle.
[0011] The approach described herein may be employed in a variety
of engine types, and a variety of engine-driven systems. Some of
these systems may be stationary, while others may be on semi-mobile
or mobile platforms. Semi-mobile platforms may be relocated between
operational periods, such as mounted on flatbed trailers. Mobile
platforms include self-propelled vehicles. Such vehicles can
include on-road transportation vehicles and off-highway vehicles
(OHV), the latter of which include mining equipment, marine
vessels, and locomotives and other rail vehicles. For clarity of
illustration, a locomotive is provided as an example of a mobile
platform supporting a system incorporating an embodiment of the
invention.
[0012] Before further discussion of the approach for draining fluid
from a turbocharger turbine, an example of a platform is disclosed
in which the engine system may be installed in a vehicle, such as a
rail vehicle. For example, FIG. 1 shows a block diagram of an
embodiment of a vehicle system 100 (e.g., a locomotive system),
herein depicted as a rail vehicle 106, configured to run on a rail
102 via a plurality of wheels 110. As depicted, the rail vehicle
106 includes an engine 104. In other non-limiting embodiments, the
engine 104 may be a stationary engine, such as in a power-plant
application, or an engine in a marine vessel or off-highway vehicle
propulsion system as noted above.
[0013] The engine 104 receives intake air for combustion from an
intake, such as an intake manifold 115. The intake may be any
suitable conduit or conduits through which gases flow to enter the
engine. For example, the intake may include the intake manifold
115, the intake passage 114, and the like. The intake passage 114
receives ambient air from an air filter (not shown) that filters
air from outside of a vehicle in which the engine 104 may be
positioned. Exhaust gas resulting from combustion in the engine 104
is supplied to an exhaust, such as exhaust passage 116. The exhaust
may be any suitable conduit through which gases flow from the
engine. For example, the exhaust may include an exhaust manifold
117, the exhaust passage 116, and the like. Exhaust gas flows
through the exhaust passage 116, and out of an exhaust stack of the
rail vehicle 106. In one example, the engine 104 is a diesel engine
that combusts air and diesel fuel through compression ignition. In
other non-limiting embodiments, the engine 104 may combust fuel
including gasoline, kerosene, biodiesel, or other petroleum
distillates of similar density through compression ignition (and/or
spark ignition).
[0014] In one embodiment, the rail vehicle 106 is a diesel-electric
vehicle. As depicted in FIG. 1, the engine 104 is coupled to an
electric power generation system, which includes an
alternator/generator 140 and electric traction motors 112. For
example, the engine 104 is a diesel engine that generates a torque
output that is transmitted to the alternator/generator 140 which is
mechanically coupled to the engine 104. The alternator/generator
140 produces electrical power that may be stored and applied for
subsequent propagation to a variety of downstream electrical
components. As an example, the alternator/generator 140 may be
electrically coupled to a plurality of traction motors 112 and the
alternator/generator 140 may provide electrical power to the
plurality of traction motors 112. As depicted, the plurality of
traction motors 112 are each connected to one of a plurality of
wheels 110 to provide tractive power to propel the rail vehicle
106. One example configuration includes one traction motor per
wheel. As depicted herein, six pairs of traction motors correspond
to each of six pairs of wheels of the rail vehicle. In another
example, alternator/generator 140 may be coupled to one or more
resistive grids 142. The resistive grids 142 may be configured to
dissipate excess engine torque via heat produced by the grids from
electricity generated by alternator/generator 140.
[0015] In the embodiment depicted in FIG. 1, the engine 104 is a
V-12 engine having twelve cylinders. In other examples, the engine
may be a V-6, V-8, V-10, V-16, I-4, I-6, I-8, opposed 4, or another
engine type. As depicted, the engine 104 includes a subset of
cylinders 105, which includes six cylinders that supply exhaust gas
exclusively to a first exhaust manifold 117, and a subset of
cylinders 107, which includes six cylinders that supply exhaust gas
exclusively to a second exhaust manifold 119. In other embodiments,
all cylinders may supply exhaust gas to a single exhaust
manifold.
[0016] As depicted in FIG. 1, the cylinders 105 and cylinders 107
are coupled to the exhaust passage 116 to route exhaust gas from
the engine to atmosphere (after it passes through a muffler 130 and
first and second turbochargers 120 and 124).
[0017] As depicted in FIG. 1, the vehicle system 100 further
includes a two-stage turbocharger with the first turbocharger 120
and the second turbocharger 124 arranged in series, each of the
turbochargers 120 and 124 arranged between the intake passage 114
and the exhaust passage 116. The two-stage turbocharger increases
air charge of ambient air drawn into the intake passage 114 in
order to provide greater charge density during combustion to
increase power output and/or engine-operating efficiency. The first
turbocharger 120 operates at a relatively lower pressure, and
includes a first turbine 121 which drives a first compressor 122.
The first turbine 121 and the first compressor 122 are mechanically
coupled via a first shaft 123. The first turbocharger may be
referred to the "low-pressure stage" of the turbocharger. The
second turbocharger 124 operates at a relatively higher pressure,
and includes a second turbine 125 which drives a second compressor
126. The second turbocharger may be referred to the "high-pressure
stage" of the turbocharger. The second turbine and the second
compressor are mechanically coupled via a second shaft 127.
[0018] As explained above, the terms "high pressure" and "low
pressure" are relative, meaning that "high" pressure is a pressure
higher than a "low" pressure. Conversely, a "low" pressure is a
pressure lower than a "high" pressure.
[0019] As used herein, "two-stage turbocharger" may generally refer
to a multi-stage turbocharger configuration that includes two or
more turbochargers. For example, a two-stage turbocharger may
include a high-pressure turbocharger and a low-pressure
turbocharger arranged in series, three turbocharger arranged in
series, two low pressure turbochargers feeding a high pressure
turbocharger, one low pressure turbocharger feeding two high
pressure turbochargers, etc. In one example, three turbochargers
are used in series. In another example, only two turbochargers are
used in series.
[0020] While a high-pressure turbocharger including a high-pressure
turbine coupled to a high-pressure compressor is illustrated, in
some embodiments the high-pressure compressor may not be coupled to
a high-pressure compressor but may instead be driven by an
alternate mechanism, such as via a coupling to the engine, via a
motor, etc.
[0021] In the embodiment shown in FIG. 1, the second turbocharger
124 is provided with a turbine bypass valve 128 which allows
exhaust gas to bypass the second turbocharger 124. The turbine
bypass valve 128 may be opened, for example, to divert the exhaust
gas flow away from the second turbine 125. In this manner, the
rotating speed of the compressor 126, and thus the boost provided
by the turbochargers 120, 124 to the engine 104 may be regulated
during steady state conditions. Additionally, the first
turbocharger 120 may also be provided with a turbine bypass valve.
In other embodiments, only the first turbocharger 120 may be
provided with a turbine bypass valve, or only the second
turbocharger 124 may be provided with a turbine bypass valve.
Additionally, the second turbocharger may be provided with a
compressor bypass valve (not shown), which allows gas to bypass the
second compressor 126 to avoid compressor surge, for example. In
some embodiments, first turbocharger 120 may also be provided with
a compressor bypass valve, while in other embodiments, only first
turbocharger 120 may be provided with a compressor bypass
valve.
[0022] A compressed air line 129 may couple the outlet of
high-pressure compressor 126 to low-pressure turbine 121. As will
be explained in more detail below with respect to FIG. 2,
compressed air line 129 may provide air of higher pressure than the
exhaust downstream of low-pressure turbine 121 in order to prevent
leakage of exhaust out of turbine 121 during engine operation. In
some embodiments, compressed air line 129 may couple the outlet of
a compressor of a supercharger (not shown in FIG. 1) driven by the
engine.
[0023] The vehicle system 100 further includes a muffler 130 or
other silencer. Muffler 130 may be open to atmosphere via one or
more exhaust stacks (not shown). Exhaust gas exiting first turbine
121 may travel through muffler 130 before being expelled to
atmosphere.
[0024] The vehicle system 100 further includes the control unit
180, which is provided and configured to control various components
related to the vehicle system 100. In one example, the control unit
180 includes a computer control system. The control unit 180
further includes non-transitory, computer readable storage media
(not shown) including code for enabling on-board monitoring and
control of engine operation. The control unit 180, while overseeing
control and management of the vehicle system 100, may be configured
to receive signals from a variety of engine sensors, as further
elaborated herein, in order to determine operating parameters and
operating conditions, and correspondingly adjust various engine
actuators to control operation of the vehicle system 100. For
example, the control unit 180 may receive signals from various
engine sensors including, but not limited to, engine speed, engine
load, boost pressure, ambient pressure, exhaust temperature,
exhaust pressure, etc. Correspondingly, the control unit 180 may
control the vehicle system 100 by sending commands to various
components such as traction motors, alternator, cylinder valves,
throttle, heat exchangers, wastegates or other valves or flow
control elements, etc.
[0025] FIG. 2 shows a cross-section of an embodiment of a
turbocharger 200 that may be coupled to an engine. Turbocharger 200
may be one stage of a multi-stage turbocharger. In one example,
turbocharger 200 may be a low-pressure turbocharger, such as
turbocharger 120 described above with reference to FIG. 1. In one
example, the turbocharger may be bolted to the engine. In another
example, the turbocharger 200 may be coupled between the exhaust
passage and the intake passage of the engine. In other examples,
the turbocharger may be coupled to the engine by any other suitable
manner.
[0026] The turbocharger 200 includes a turbine stage 202 and a
compressor 204. Exhaust gases from the engine pass through the
turbine stage 202, and energy from the exhaust gases is converted
into rotational kinetic energy to rotate a shaft 206 which, in
turn, drives the compressor 204. Ambient intake air is compressed
(e.g., pressure of the air is increased) as it is drawn through the
rotating compressor 204 such that a greater mass of air may be
delivered to the cylinders of the engine.
[0027] The turbocharger includes a casing 210. In some embodiments,
the turbine stage 202 and the compressor 204 may have separate
casings which are bolted together, for example, such that a single
unit (e.g., turbocharger 200) is formed. As an example, the
turbocharger may have a casing made of cast iron and the compressor
may have a casing made of an aluminum alloy.
[0028] The turbocharger 200 further includes bearings 208 to
support the shaft 206, such that the shaft may rotate at a high
speed with reduced friction. As depicted in FIG. 2, the
turbocharger 200 further includes two non-contact seals (e.g.,
labyrinth seals), a turbine labyrinth seal 214 positioned between
an oil cavity 212 and the turbine 202 and a compressor labyrinth
seal 216 positioned between the oil cavity 212 and the compressor
204.
[0029] Exhaust gas may enter through an inlet, such as gas inlet
transition region 220, and pass over a nose piece 222. A nozzle
ring 224 may include airfoil-shaped vanes arranged
circumferentially to form a complete 360.degree. assembly. The
nozzle ring 224 may act to optimally direct the exhaust gas to a
turbine disc/blade assembly, including blades 226 and a turbine
disc 228, coupled to the shaft 206. In some embodiments, the
turbine disc and blades may be an integral component, known as a
turbine blisk. The rotating assembly of the turbine, including the
turbine disc, blades, and shaft, may collectively be referred to as
the turbine rotor.
[0030] The blades 226 may be airfoil-shaped blades extending
outwardly from the turbine disc 228, which rotates about the
centerline axis of the engine. An annular shroud 230 is coupled to
the casing at a shroud mounting flange 232 and arranged so as to
closely surround the blades 226 and thereby define the flowpath
boundary for the exhaust stream flowing through the turbine stage
202. Cavity 234 may be an open space under shroud 230 that may be
configured to receive exhaust gas that has passed over the turbine
rotor. Cavity 234 may be open to atmosphere, in that turbine casing
210 at the top of the turbine stage may open to atmosphere and lead
down to cavity 234. As such, water passing through the exhaust
stack and muffler (e.g., rain water) may enter turbine casing 210
and collect in cavity 234. Cavity 234 may be the vertically lowest
point of the turbine casing that is open to atmosphere, relative to
the vehicle ground. For example, the vertical low point may be a
lowest point when the turbocharger is installed in a vehicle and
the vehicle is on a level surface for motive operation.
[0031] As explained previously, if water is allowed to accumulate
in the turbine casing while the engine is shut down, the build-up
of various particulates on the turbine disc and blades may dissolve
when exposed to the accumulated water. This may result in an
unbalanced turbine rotor, leading to turbocharger degradation. To
drain any accumulated water, a drain passage 236 may be coupled to
turbine casing 210 in cavity 234. The drain passage 236 may
comprise an opening at the bottom of cavity 234 and/or other
suitable fluid drainage configuration, such as a straw, nipple,
etc. Drain passage 236 may lead out of turbine casing 210 and to
atmosphere (e.g., external to the vehicle/system in which the
turbocharger is installed). In this way, fluid such as water may
passively drain out of turbine stage 202.
[0032] However, drain passage 236 may provide a path for the
exhaust gas flowing through the turbocharger. In some examples, the
exhaust gas may leak out of turbine stage 202 to the vehicle cabin
or other vehicle compartment via the drain passage 236. To prevent
the leak of exhaust gas via drain passage 236, drain passage 236
may be supplied with pressurized air during engine operation. In
the example depicted in FIG. 2, compressed intake air from
downstream of a high-pressure compressor (such as second compressor
126 of FIG. 1) may be directed to drain passage 236 via compressed
air line 238, similar to the compressed air line 129 illustrated in
FIG. 1.
[0033] In an example, compressed air line 238 may include an air
jet 240 or ejector, venturi, nozzle, etc., that creates an increase
in velocity of the air moving through compressed air line 238. Air
jet 240 may include a restricted throat or other configuration that
creates vacuum when compressed air is drawn through compressed air
line 238. This vacuum may act to also drawn in air from atmosphere
and/or otherwise block leakage of exhaust from drain passage 236.
As such, to prevent leakage of exhaust from drain passage 236, air
at greater than atmospheric pressure is supplied to the compressed
air line during all engine operating conditions.
[0034] The turbine stage 202 is an axial turbine, as the exhaust
flow impels on the turbine blades in an axial direction relative to
the center axis of the engine. However, in some embodiments,
turbine stage 202 may be a radial turbine.
[0035] FIG. 3 is a flow chart illustrating a method 300 for
removing accumulated fluid from a turbine casing. At 302, method
300 includes sealing a flow of exhaust gas from a low-pressure
turbine to atmosphere through a drain passage during engine
operation. As explained above, the drain passage may be coupled to
a cavity of the low-pressure turbine that may accumulate water. The
drain passage may be open to atmosphere in order to passively drain
water out of the turbine. However, to ensure exhaust gas flowing
through the turbocharger during engine operation does not leak out
of the turbine, the drain passage may be sealed. This includes, at
304, directing air from a high-pressure compressor outlet to the
drain passage. The air from the high-pressure compressor may be of
higher pressure than the exhaust in the turbine.
[0036] At 306, method 300 includes draining fluid from the
low-pressure turbine to atmosphere through the drain passage during
engine off conditions. When the engine is not operating, exhaust is
not produced and thus no exhaust is present in the turbine to leak
out of the drain passage. Thus, compressed air is not supplied to
the drain passage, and any accumulated fluid (e.g., water) is
allowed to passively drain via the drain passage.
[0037] An embodiment relates to turbocharger. The turbocharger
comprises a turbine including a casing that houses a rotor, a drain
passage coupled to the casing, and an air jet coupled to the drain
passage. The air jet is configured to supply intake air from a
high-pressure compressor outlet to the drain passage. Another
embodiment relates to a vehicle having such a turbocharger
installed as part of the vehicle. For example, in embodiments, the
vehicle is a locomotive or other rail vehicle.
[0038] Another embodiment relates to a system. The system comprises
an engine, a first turbocharger including a first turbine
mechanically coupled to a first compressor, and a second
turbocharger including a second turbine located downstream of the
first turbine in an exhaust flow path. The second turbine is
mechanically coupled to a second compressor. The second compressor
is located upstream of the first compressor in an intake flow path.
The system further comprises a drain passage coupling the second
turbine to atmosphere, and a compressed air line coupling the drain
passage to an outlet of the first compressor. An air jet may be
coupled to the compressed air line. In operation, in embodiments,
the drain passage is configured to passively drain fluid from the
second turbine when the engine is not operating, and the drain
passage is configured to seal a flow of exhaust gas from the second
turbine to atmosphere when the engine is operating (e.g., when the
engine is operating, compressed intake air flows from the outlet of
the first compressor through the compressed air line to the drain
passage in order to seal the flow of exhaust gas). Another
embodiment relates to a vehicle comprising a vehicle platform, and
such a system attached to the vehicle platform. In embodiments, the
vehicle is a locomotive or other rail vehicle.
[0039] As used herein, an element or step recited in the singular
and proceeded with the word "a" or "an" should be understood as not
excluding plural of said elements or steps, unless such exclusion
is explicitly stated. Furthermore, references to "one embodiment"
of the present invention are not intended to be interpreted as
excluding the existence of additional embodiments that also
incorporate the recited features. Moreover, unless explicitly
stated to the contrary, embodiments "comprising," "including," or
"having" an element or a plurality of elements having a particular
property may include additional such elements not having that
property. The terms "including" and "in which" are used as the
plain-language equivalents of the respective terms "comprising" and
"wherein." Moreover, the terms "first," "second," and "third," etc.
are used merely as labels, and are not intended to impose numerical
requirements or a particular positional order on their objects.
[0040] This written description uses examples to disclose the
invention, including the best mode, and also to enable a person of
ordinary skill in the relevant art to practice the invention,
including making and using any devices or systems and performing
any incorporated methods. The patentable scope of the invention is
defined by the claims, and may include other examples that occur to
those of ordinary skill in the art. Such other examples are
intended to be within the scope of the claims if they have
structural elements that do not differ from the literal language of
the claims, or if they include equivalent structural elements with
insubstantial differences from the literal languages of the
claims.
* * * * *