U.S. patent application number 13/956415 was filed with the patent office on 2014-02-06 for methods and systems for powering a rail vehicle.
This patent application is currently assigned to General Electric Company. The applicant listed for this patent is General Electric Company. Invention is credited to Ronald Gene BILLIG, Taral SHAH.
Application Number | 20140033946 13/956415 |
Document ID | / |
Family ID | 50024143 |
Filed Date | 2014-02-06 |
United States Patent
Application |
20140033946 |
Kind Code |
A1 |
BILLIG; Ronald Gene ; et
al. |
February 6, 2014 |
METHODS AND SYSTEMS FOR POWERING A RAIL VEHICLE
Abstract
Various methods and systems are provided for supplying gaseous
natural gas and electrical energy to a rail vehicle. In one
embodiment, a method comprises receiving natural gas at an engine
on board a rail vehicle during engine operation, stopping the
engine in response to an engine shutdown request, and receiving
electrical energy from off board the rail vehicle to power the rail
vehicle for at least a period while the engine is stopped.
Inventors: |
BILLIG; Ronald Gene;
(Hermitage, PA) ; SHAH; Taral; (Wattsburg,
PA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
General Electric Company |
Schenectady |
NY |
US |
|
|
Assignee: |
General Electric Company
Schenectady
NY
|
Family ID: |
50024143 |
Appl. No.: |
13/956415 |
Filed: |
August 1, 2013 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
61678191 |
Aug 1, 2012 |
|
|
|
Current U.S.
Class: |
105/35 ;
105/62.1 |
Current CPC
Class: |
F17C 2270/0173 20130101;
B61C 5/00 20130101; F17C 2250/043 20130101; F17C 2250/0439
20130101; Y02T 30/16 20130101; F17C 2223/0161 20130101; F17C
2260/044 20130101; B61C 17/12 20130101; F17C 2265/031 20130101;
F17C 2250/01 20130101; B61C 7/04 20130101; F17C 2265/037 20130101;
F17C 2265/066 20130101; F17C 2203/0391 20130101; Y02T 30/00
20130101; F17C 2225/035 20130101; F17C 2265/07 20130101; F17C 7/00
20130101; F17C 2227/0332 20130101; F17C 2227/0393 20130101; F17C
1/00 20130101; F17C 13/00 20130101; B61C 17/02 20130101; F17C
2221/033 20130101; F17C 2223/033 20130101; F17C 2225/0123
20130101 |
Class at
Publication: |
105/35 ;
105/62.1 |
International
Class: |
B61C 5/00 20060101
B61C005/00; B61C 7/04 20060101 B61C007/04 |
Claims
1. A method, comprising: receiving natural gas at an engine on
board a rail vehicle during engine operation; stopping the engine
in response to an engine shutdown request; and receiving electrical
energy from off board the rail vehicle to power the rail vehicle
for at least a period while the engine is stopped.
2. The method of claim 1, wherein receiving electrical energy
includes receiving at least a portion of electrical energy
generated by an off board natural gas-fueled engine and further
comprising powering one or more rail vehicle electronic components
on board the rail vehicle with the at least the portion of
electrical energy.
3. The method of claim 2, wherein the one or more rail vehicle
electronic components comprises at least one of a compressor, a
blower, a battery, communication equipment, safety equipment, or a
controller.
4. The method of claim 2, further comprising powering one or more
fuel tender electronic components on board a fuel tender with at
least a portion of the electrical energy generated by the natural
gas-fueled engine.
5. The method of claim 4, wherein the one or more fuel tender
electronic components includes one or more of a regasification unit
or a cryogenic unit.
6. The method of claim 2, further comprising sending a request to a
fuel tender to supply natural gas to the natural gas-fueled engine
and operating the natural gas-fueled engine to generate the
electrical energy.
7. The method of claim 6, wherein sending the request to the fuel
tender to supply natural gas to the natural gas-fueled engine
includes sending a request to deliver gaseous natural gas from a
regasification unit on board the fuel tender to the natural
gas-fueled engine.
8. The method of claim 6, wherein sending the request to the fuel
tender to supply natural gas to the natural gas-fueled engine
includes sending a request to deliver gaseous natural gas from a
reservoir on board the fuel tender to the natural gas-fueled
engine.
9. The method of claim 6, wherein sending a request to supply
natural gas to the natural gas-fueled engine includes sending a
request to deliver boil-off gas from liquefied natural gas being
stored in the fuel tender to the natural gas-fueled engine.
10. A method, comprising: signaling an engine on board a rail
vehicle to enter a shutdown mode; transmitting a request for
electricity generation to an engine that is off board the rail
vehicle and that is fluidically coupled to a fuel source; receiving
the electricity generated by the off board engine at the rail
vehicle; and powering at least one auxiliary load on board the rail
vehicle with the received electricity.
11. The method of claim 10, wherein the at least one auxiliary load
includes one or more of a blower, a traction motor, a compressed
air unit, a radiator fan, an electronics control system, a lighting
system, a sensor, a communication system, a positive train control
or collision avoidance system, or an energy storage unit.
12. The method of claim 10, further comprising maintaining an
electronic control system of the rail vehicle in an active state
during the shutdown mode.
13. The method of claim 10, wherein the electricity generated off
board of the rail vehicle is generated by powering the off board
engine with boil-off gas from liquefied natural gas.
14. The method of claim 10, wherein the electricity generated by
the engine off board the rail vehicle is generated by powering the
off board engine with gaseous natural gas received from a gas
reservoir.
15. The method of claim 10, wherein the electricity generated by
the off board engine is generated by powering the off board engine
with gaseous natural gas received from a regasification unit.
16. A method, comprising: sending an engine condition signal from a
rail vehicle to a fuel tender coupled to the rail vehicle;
requesting a natural gas-fueled engine to start based at least in
part on receiving the engine condition signal; and powering at
least one auxiliary load on board the rail vehicle with electrical
energy received from the natural gas-fueled engine.
17. The method of claim 16, wherein the engine condition signal
indicates an engine shutdown request, and wherein the at least one
auxiliary load includes one or more of an electronics control
system, a blower, a traction motor, a compressed air unit, a
radiator fan, a lighting system, a collision avoidance or positive
train control system, safety equipment, communication equipment, a
sensor, or an energy storage unit.
18. The method of claim 16, wherein the engine condition signal
indicates one or both of an engine load and a ratio of gaseous
natural gas to an alternate fuel, and further comprising: heating
thermal fluid by the natural gas-fueled engine; regasifying
liquefied natural gas to form gaseous natural gas using the thermal
fluid that is heated; and consuming the gaseous natural gas by a
multi-fuel engine of the rail vehicle.
19. The method of claim 18, wherein the alternate fuel is diesel
fuel, and further comprising adjusting the ratio of diesel fuel to
gaseous natural gas.
20. The method of claim 16, further comprising powering at least
one electrical load off board the rail vehicle, wherein the off
board electrical load is at least one of electrically heating a
regasification unit or cryogenically maintaining liquid natural
gas.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims priority to U.S. Provisional
Application No. 61/678,191, filed Aug. 1, 2012, which is hereby
incorporated by reference herein in its entirety.
FIELD
[0002] Embodiments of the subject matter disclosed herein relate to
a rail vehicle, and related methods for supplying fuel to an engine
of the rail vehicle.
BACKGROUND
[0003] Locomotives (or other vehicles) typically include a prime
mover that is powered by a fuel source to generate mechanical
energy. In one example of a locomotive, mechanical energy generated
by the prime mover may be converted to electrical energy that is
used to power traction motors and other components and systems of
the locomotive. In some examples, the prime mover may be a
combustion engine that is fueled by diesel, gasoline, or other
liquid petroleum distillates. In other examples the engine may
additionally or alternatively utilize a gaseous fuel, such as
natural gas.
[0004] In light of its favorable energy content, liquefied natural
gas (LNG) may be used as a fuel source for a locomotive prime
mover. Particularly for long-haul applications, it may also be
desirable to utilize a tender car, also known as a fuel tender, for
carrying one or more LNG storage tanks Prior to use by a
locomotive's natural gas-fueled engine, LNG is typically vaporized
into gaseous natural gas (compressed natural gas, CNG). Such
vaporization is often accomplished by heating the LNG with a heat
source.
[0005] In some examples such a heat source may take the form of a
heat exchanger on board the locomotive. In these examples the LNG
may be transferred from the tender car to the heat exchanger on the
locomotive across an interface between the tender car and the
locomotive. Such an interface, however, requires suitable cryogenic
hosing, cryogenic coupling components, and associated design
constraints and maintenance requirements. Transferring LNG across
such an interface also creates the potential for LNG leaks.
[0006] In other examples, a heat exchanger may be located on board
the tender car. Heated cooling fluid from the locomotive engine may
be transferred from the locomotive to the heat exchanger on the
tender car across an interface. However, as with transferring LNG
across an interface, this configuration requires additional
insulated hosing and coupling components that present design
challenges and risks. Additionally, LNG storage tanks typically
generate boil-off gas that may accumulate in the tank. To avoid
excess pressure build up, such boil-off gas is typically vented
from the storage tanks to atmosphere. Such venting of natural gas
may raise environmental concerns.
[0007] The locomotive engine may also enter an idle mode when power
for the locomotive propulsion system is not required. Nevertheless,
instead of entering a shutdown mode, the locomotive engine may
continue to idle to generate electricity needed by components
and/or systems on board the locomotive. Such idling may produce
undesirable exhaust emissions and reduce overall operating
efficiencies.
BRIEF DESCRIPTION OF THE INVENTION
[0008] In one embodiment, a method comprises receiving natural gas
at an engine on board a rail vehicle during engine operation,
stopping the engine in response to an engine shutdown request, and
receiving electrical energy from off board the rail vehicle to
power the rail vehicle for at least a period while the engine is
stopped.
[0009] In this way, the engine of the rail vehicle may be
maintained in a shutdown mode for an extended period, while also
receiving electricity to power auxiliary loads and components on
board the rail vehicle. Accordingly, by facilitating idle time
reduction of the engine, fuel economy and reduced emissions
benefits may be achieved.
[0010] 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 subject
matter.
BRIEF DESCRIPTION OF THE DRAWINGS
[0011] The present invention will be better understood from reading
the following description of non-limiting embodiments, with
reference to the attached drawings, wherein below:
[0012] FIG. 1 shows a schematic diagram of two locomotives, a fuel
tender, and a freight car according to an embodiment of the present
disclosure.
[0013] FIG. 2 shows a more detailed view of an exemplary embodiment
of a fuel tender and a portion of a natural gas-fueled locomotive
according to an embodiment of the present disclosure.
[0014] FIG. 3 shows a high level flow chart of a method for
receiving fuel for use by a vehicle according to an embodiment of
the present disclosure.
[0015] FIG. 4 shows a high level flow chart of a method for a rail
vehicle according to an embodiment of the present disclosure.
[0016] FIG. 5 shows a high level flow chart of a method for
maintaining a rail vehicle according to an embodiment of the
present disclosure.
[0017] FIG. 6 shows a high level flow chart of another method for
maintaining a rail vehicle according to an embodiment of the
present disclosure.
DETAILED DESCRIPTION
[0018] The following description relates to various embodiments of
controlling a rail vehicle. Specifically, the rail vehicle may
receive gaseous natural gas to power a multi-fuel engine on board
the rail vehicle and/or electrical energy to power electronic
components on board the rail vehicle. The rail vehicle may receive
the gaseous natural gas and electrical energy from a remote liquid
fuel container (e.g., a liquid fuel container located off-board the
rail vehicle) and a natural gas-fueled engine, respectively, both
the liquid fuel container and the natural gas-fueled engine being
off board the rail vehicle. In one example, the liquid fuel
container and the natural gas-fueled engine are on board a fuel
tender coupled to the rail vehicle, as shown at FIGS. 1-2. As
described in more detail below, in some embodiments the rail
vehicle may send signals or requests to the fuel tender to store
liquefied natural gas (LNG) and convert the LNG to gaseous natural
gas. A natural gas-fueled engine on board the rail vehicle (e.g.,
locomotive) may then receive the gaseous natural gas from the fuel
tender. In other embodiments, other fuels including but not limited
to biogas, hydrogen, or a combination thereof, may be utilized.
FIGS. 3-4 present example methods for receiving gaseous natural gas
converted from LNG at the rail vehicle. In response to signals from
the rail vehicle, the natural gas-fueled engine on board the fuel
tender may be operated to produce electrical energy. Methods for
generating and supplying electrical energy to the rail vehicle are
presented at FIGS. 5-6.
[0019] FIG. 1 shows a schematic diagram of a first locomotive 100
removably coupled to a second locomotive 104 and to a fuel tender
110 according to the present disclosure. (Although locomotives are
illustrated in the embodiment of FIG. 1 and other embodiments, such
embodiments are applicable to rail vehicles more generally, that
is, the locomotives could be other types of rail vehicles such as
self-propelled mining/ore carts, self-propelled freight cars, or
the like.) The fuel tender 110 is shown removably coupled to a
freight car 108. It will be appreciated that additional fuel
tenders, freight cars, locomotives, and/or other rail vehicles may
also be removably connected to the freight car 108 and/or the
second locomotive 104. It will also be appreciated that the order
of the various rail vehicles shown in FIG. 1 may be modified.
[0020] The first and second locomotives 100 and 104, fuel tender
110, and freight car 108 are configured to run on a rail 102 (or
set of rails) via a plurality of wheels. In FIG. 1, the fuel tender
110 is positioned behind the first locomotive 100 and removably
connected to the freight car 108. In other configurations, the fuel
tender 110 may be positioned in front of the locomotive 100 and/or
may not be connected to the freight car 108 or other rail car. In
still other configurations, one or more other rail vehicles may be
located between the fuel tender 110 and the locomotive 100.
[0021] In one example the first locomotive 100 and second
locomotive 104 are powered for propulsion, while the fuel tender
110 and freight car 108 are non-powered for propulsion. It will be
appreciated that in other examples one or more of the fuel tender
110 and freight car 108 may also be powered for propulsion by, for
example, one or more traction motors.
[0022] Additionally, FIG. 1 shows a tender controller 220 on board
the fuel tender 110, a first locomotive controller 136 on board the
first locomotive 100, and a second locomotive controller 194 on
board the second locomotive 104. As described further below, the
first locomotive controller 136 controls operation of a primary
engine 118 and the tender controller 220 controls operation of the
fuel tender 110. However, the first locomotive controller 136 may
send signals and/or requests (e.g., commands) to the tender
controller 220 regarding operation of the fuel tender 110. For
example, the first locomotive controller 136 may send a request to
the tender controller 220 of the fuel tender 110 to convert liquid
natural gas to gaseous natural gas (or to convert another fuel in
fuel tender from a first, liquid phase to a second, gaseous phase)
and send the gaseous natural gas via one or more fuel lines to an
engine of the first locomotive 100 (e.g., the primary engine 118),
as described further below. Further, the first locomotive
controller 136 may include instructions stored thereon (e.g.,
within a memory of the controller) for sending a plurality of
requests to the tender controller 220 and to components on board
the fuel tender 110. The tender controller 220 may then control
actuators and/or components on board the fuel tender 110 based on
the requests sent from the first locomotive controller 136 on board
the first locomotive 100. As shown schematically in FIG. 1 by way
of the dotted lines, the tender controller 220, first locomotive
controller 136, and second locomotive controller 194 all
communicate electronically with one another.
[0023] Turning now to FIG. 2, the first locomotive 100 (or other
rail vehicle) includes an engine system 112 that comprises the
primary engine 118, which has a plurality of cylinders. The primary
engine 118 may be referred to herein as the locomotive engine. In
one embodiment, each cylinder is configured to have at least one
gaseous fuel injector and at least one liquid fuel injector. In the
depicted example, the first locomotive 100 is configured as a
locomotive powered by the engine system 112 that operates with
various fuels, such as a first fuel and a second fuel. (That is, in
embodiments, the engine system is operable by the first fuel by
itself, and is also operable by the second fuel by itself, with the
first and second fuels being stored in separate respective fuel
containers. In other embodiments, alternatively of additionally,
the engine system may be operable by the first and second fuels
co-mixed, and/or otherwise by the first and second fuels
concurrently during an engine cycle, e.g., during an engine cycle
first a portion of the first fuel is provided into a cylinder, and
then a portion of the second fuel is provided into the cylinder.)
The fuels may include a liquid fuel, such as diesel fuel, an
alternative fuel, and/or a gaseous fuel, or combinations thereof.
In one example, the primary engine 118 is a dual fuel engine, such
as a gas turbine, compression ignition engine, or spark ignition
engine, a first fuel is gaseous natural gas that is received from
the fuel tender 110 via fluidic coupling 114 (e.g., fuel line), and
a second fuel is diesel fuel received from a diesel storage tank
116 via fluidic coupling 122 on board the first locomotive 100.
While engine system 112 is configured in one embodiment herein as a
multi-fuel engine operating with diesel fuel and natural gas, in
other examples engine system 112 may use various combinations of
fuels other than diesel and natural gas.
[0024] The primary engine 118 is configured to generate a torque
that is transmitted to a power conversion unit 120 along a drive
shaft 124. The power conversion unit 120 is configured to convert
the torque into electrical energy that is delivered via electrical
bus 128 to at least one traction motor 132 and to a variety of
downstream electrical components in the first locomotive 100. Such
components may include, but are not limited to, compressors 140,
blowers 144, batteries 148, an electronics control system 134
comprising one or more controllers 136, shutoff valves, pressure
regulators, radiators, lights, on-board monitoring systems,
displays, climate controls (not shown), and the like.
[0025] Based on the nature of the generated electrical output, the
electrical bus 128 may be a direct current (DC) bus (as depicted)
or an alternating current (AC) bus. In one example the power
conversion unit 120 includes an alternator (not shown) that is
connected in series to one or more rectifiers (not shown) that
convert the alternator's electrical output to DC electrical power
prior to transmission along the electrical bus 128. The alternator
may include, for example, a high-speed generator, a generator
machine whose stator flux is synchronous to the rotor flux, or an
asynchronous machine.
[0026] Based on the configuration of a downstream electrical
component receiving power from the electrical bus 128, one or more
inverters may be configured to invert the electrical power from the
electrical bus prior to supplying electrical power to the
downstream component. In one example, a single inverter may supply
AC electrical power from a DC electrical bus to a plurality of
components. In another non-limiting embodiment, each of a plurality
of distinct inverters may supply electrical power to a distinct
component.
[0027] The traction motor 132 receives electrical power from the
power conversion unit 120 and is coupled to one or more
axles/driving wheels 152. In this manner, the traction motor 132 is
configured to drive the axles/driving wheels 152 along the rail
102. It should be appreciated that the number of sets of
axles/driving wheels 152 may vary, and that one or more traction
motors 132 may be provided for each set of axles/driving wheels.
The traction motor 132 may be an AC motor. Accordingly, an inverter
paired with the traction motor 132 may convert DC input to an
appropriate AC input, such as a three-phase AC input, for
subsequent use by the traction motor. In other non-limiting
embodiments, traction motor 132 may be a DC motor directly
employing the output of the power conversion unit 120 after
rectification and transmission along the DC bus 128.
[0028] One example of a locomotive configuration includes one
inverter/traction motor 132 pair per axle/driving wheel 152.
Traction motor 132 may also be configured to act as a generator for
providing dynamic braking to brake the first locomotive 100. In
particular, during dynamic braking, the traction motor may provide
torque in a direction that is opposite from the rolling direction,
thereby generating electricity that is dissipated as heat by
resistors (not shown) connected to the electrical bus 128.
[0029] The first locomotive controller 136 on board the first
locomotive 100 controls the primary engine 118 by sending commands
to various engine control hardware components such as invertors,
alternators, relays, fuel injectors, fuel pumps (not shown), or the
like. As described further below, in one example, the first
locomotive controller 136 also monitors locomotive operating
parameters in active operation, idle and shutdown states. Such
parameters may include, but are not limited to, manifold air
temperature (MAT), ambient temperature, engine oil temperature,
compressor air pressure, main air reserve pressure, battery
voltage, a battery state of charge, brake cylinder pressure, or the
like. The first locomotive controller 136 further includes computer
readable storage media (not shown) including code for enabling
on-board monitoring and control of rail vehicle operation.
[0030] The first locomotive controller 136, while overseeing
control and management of the primary engine 118 and other
locomotive components, may be configured to receive signals from a
variety of engine sensors, as further described herein. The first
locomotive controller 136 may utilize such signals to determine
operating parameters and operating conditions, and correspondingly
adjust various engine actuators to control operation of the first
locomotive 100. For example, the first locomotive controller 136
may receive signals from various engine sensors including, but not
limited to, engine speed, engine load, boost pressure, exhaust
pressure, ambient pressure, exhaust temperature, or the like.
Correspondingly, the first locomotive controller 136 may control
the locomotive 100 by sending commands to various components such
as fraction motors, alternators, cylinder valves, throttles, or the
like. As described further below, the first locomotive controller
136 at least partially controls operation of the fuel tender 110 by
sending commands (e.g., requests) to the tender controller 220 on
board the fuel tender. For example, the commands sent to the tender
controller 220 may include commands for controlling various
components on board the fuel tender such as a regasification unit
234, a LNG storage tank 212, or the like.
[0031] In one example, the computer readable storage media
configured in the first locomotive controller 136 may execute code
to auto-stop or auto-start the primary engine 118 by enabling, for
example, an Automatic Engine Start/Stop (AESS) control system
routine. As discussed in more detail below, the first locomotive
controller 136 also communicates with the tender controller 220 on
board the fuel tender 110 to, for example, request delivery of
gaseous natural gas for the primary engine 118. As shown in FIGS.
1-2, the first locomotive controller 136 also communicates with the
second locomotive controller 194 in the second locomotive 104 to,
for example, coordinate pass-through delivery of gaseous natural
gas from the fuel tender 110 to a natural-gas fueled engine in the
second locomotive 104. The computer readable storage media
configured in the first locomotive controller 136 may execute code
to appropriately transmit and receive such communications.
[0032] With continued reference to FIG. 2, the fuel tender 110 is
removably coupled to the first locomotive 100 and includes
axles/wheels 204 configured to travel along rail 102. In the
depicted example, the fuel tender 110 includes six pairs of
axles/wheels 204. The fuel tender 110 further includes a mechanical
coupling mechanism 208 that removably couples the fuel tender to
the first locomotive 100 for linked movement thereof. In other
examples, the fuel tender 110 may include a second coupling
mechanism (not shown) that may removably couple the fuel tender to
another rail vehicle, such as the freight car 108.
[0033] The fuel tender 110 is configured to carry one or more fuel
storage tanks In one embodiment, as shown in FIG. 2, the fuel
tender 110 includes an on-board cryogenic LNG storage tank 212 for
storing LNG. In one example, the LNG storage tank 212 may take the
form of a vacuum jacketed pressure vessel that stores LNG at
pressures ranging from approximately 50 kPa to approximately 1,700
kPa. It will be appreciated that to maintain LNG in a liquid state,
the LNG may be stored at a temperature of approximately -260
degrees Celsius or lower. In some examples, as shown in FIG. 2, the
fuel tender 110 includes a cryogenic unit 268 for helping maintain
the LNG within desired temperature and pressure ranges. In other
example, the fuel tender 110 may not include the cryogenic unit
268.
[0034] Even with efficient insulation and cryogenic refrigeration
equipment, heat typically leaks into the LNG storage tank 212 and
causes vaporization of portions of the LNG into boil-off gas. As
described in more detail below, in one example such boil-off gas
may be used to power an engine 216 located on board the fuel tender
110 (an "on-board" engine 216). For purposes of this description,
an "on-board" component, device, or other structure means that the
component or device is physically located on the vehicle being
described. For example, with respect to the fuel tender 110, a
component or structure physically located on the fuel tender is on
board the fuel tender, including when the fuel tender is coupled to
a locomotive or other rail vehicle and when the fuel tender is not
coupled to a locomotive or other rail vehicle.
[0035] In one example, as shown in FIG. 2, portions of such
boil-off gas accumulating in the LNG storage tank 212 are also
delivered to and stored in an on-board reservoir 218 that supplies
gaseous natural gas to the on-board engine 216, as discussed in
more detail below. In alternate examples, the fuel tender 110 may
not include the reservoir 218. It will also be appreciated that the
storage tank 212 may have various sizes and configurations and may
be removable from the fuel tender 110. Further, as shown in FIG. 2,
the storage tank 212 is configured to receive LNG from an external
refueling station via port 222. In alternate examples, the storage
tank 212 may revive LNG through another port or location on the
storage tank 212.
[0036] The LNG storage tank 212 supplies LNG via cryogenic LNG
fluidic coupling 226 and one or more valves 230 to a regasification
unit 234. The regasification unit 234 converts the LNG into gaseous
natural gas, i.e., vaporizes the LNG, by the application of heat to
the LNG. The gaseous natural gas is then delivered to the primary
engine 118 of the first locomotive 100 to power the primary engine
118. As shown in FIG. 2, the gaseous natural gas is delivered to
the primary engine 118 via fluidic coupling 114 and one or more
control valves 232. In some examples, as shown in FIG. 2, a
pass-through control valve 156 is provided to direct at least a
portion of the gaseous natural gas through the first locomotive 100
via a pass through fluidic coupling 160 to the second locomotive
104. In this manner, a natural gas-fueled engine in the second
locomotive 104 may be powered by gaseous natural gas from the fuel
tender 110. In alternate examples, there may not be a control valve
156 and gaseous natural gas may only be delivered to the first
locomotive 100. In yet another example, additional control valves
may be positioned in the gaseous natural gas fluidic coupling 114
to direct gaseous natural gas to additional locomotives or rail
cars.
[0037] The gaseous natural gas fluidic coupling 114 further
includes a detachable interface coupling 236 that enables the fuel
tender 110 to be decoupled from the locomotive 100. It will also be
appreciated that in other embodiments the pass-through control
valve 156 may be located on board the fuel tender 110, along with
suitable fluidic couplings to pass through fluidic coupling
160.
[0038] It will be appreciated that by converting the LNG to gaseous
natural gas on board the fuel tender 110 and supplying gaseous
natural gas to the primary engine 118, standard gaseous natural gas
conduit and interface couplings may be utilized between the fuel
tender and the locomotive 100. Advantageously, such a configuration
avoids costly cryogenic tubing and interface couplings, and the
corresponding design challenges, that would otherwise be required
for transferring LNG between the fuel tender 110 and the locomotive
100. Additionally, using such standard, low pressure gaseous
natural gas fluidic and interface couplings eliminates the
possibility of LNG leaks between the fuel tender 110 and locomotive
100.
[0039] Additionally, and in another advantage that may be realized
in the practice of some embodiments disclosed herein, the on-board
engine 216 may serve as a heat source that provides heated fluid to
the regasification unit 234. Examples of suitable fluids that may
be used include, but are not limited to, water, glycols, salt
solutions, alcohols, intake air, exhaust gas, and mixtures of two
or more of the foregoing. In one example, the on-board engine 216
may comprise a natural gas-fueled combustion engine that includes a
heat exchanger, such as a radiator, that generates heated liquid.
As shown in FIG. 2, the on-board engine 216 is fluidly coupled to
the regasification unit 234 via fluidic coupling 238 and supplies
the heated liquid to the regasification unit via the fluidic
coupling 238. The regasification unit 234 then utilizes the heated
liquid to heat the LNG and convert the LNG to gaseous natural
gas.
[0040] In other non-limiting embodiments, the heated fluid
generated by the on-board engine 216 comprises air and/or exhaust
gas resulting from combustion within the on-board engine. In one
example, the on-board engine 216 supplies heated exhaust gas to the
regasification unit 234 via fluidic coupling 240. The
regasification unit 234 then utilizes the heated exhaust gas to
heat the LNG and convert the LNG to gaseous natural gas. In another
example, the on-board engine 216 may receive ambient air that is
heated and supplied to the regasification unit 234 via fluidic
coupling 240. The regasification unit 234 may then utilize the
heated air to heat the LNG and convert the LNG to gaseous natural
gas.
[0041] In other examples, the on-board engine 216 may generate both
heated liquid and heated gas, and may supply both heated liquid and
heated gas to the regasification unit 234. It will also be
appreciated that in other examples the on-board engine 216 may
utilize one or more alternative fuels such as, for example, diesel,
gasoline, biogas, propane, or the like.
[0042] In an advantage that may be realized in the practice of some
embodiments disclosed herein, by utilizing the on-board engine 216
as a heat source to provide heated fluid to the regasification unit
234, and by converting the LNG to gaseous natural gas on board the
fuel tender 110, the fuel tender is liquidly isolated from the
first locomotive 100. For purposes of this description, "liquidly
isolated" means that neither LNG nor heated fluid is transferred
from the fuel tender 110 to the first locomotive 100, or vice
versa. Advantageously, such configurations avoid the possibility of
LNG and/or heated fluid leaks and other malfunctions that could
occur in the transfer of LNG and/or heated fluid between the fuel
tender 110 and the first locomotive 100.
[0043] In another advantage that may be realized in the practice of
some embodiments disclosed herein, the on-board engine 216 may
comprise a natural-gas fueled engine that is powered by boil-off
gas supplied from the LNG storage tank 212. In one non-limiting
example depicted in FIG. 2, the on-board engine 216 receives
boil-off gas from the storage tank 212 via boil-off gas fluidic
coupling 242, one or more control valves 244 and 248, and fluidic
coupling 252. Advantageously, in this configuration, boil-off gas
from the storage tank 212 is used to power the on-board engine 216,
and thereby avoid venting such gas to atmosphere. In this manner,
the described configuration makes productive use of such boil-off
gas while also avoiding potential environmental issues associated
with venting the gas.
[0044] In another non-limiting example depicted in FIG. 2, the
reservoir 218 on board the fuel tender 110 receives boil-off gas
from the storage tank 212 via boil-off gas fluidic coupling 242 and
control valve 248. The reservoir 218 is fluidly coupled to the
on-board engine 216 via fluidic coupling 252. Advantageously, the
reservoir 218 provides a ready source of gaseous natural gas for
starting the on-board engine 216 and for operating the on-board
engine 216.
[0045] In another non-limiting example and as depicted in FIG. 2,
the reservoir 218 also receives gaseous natural gas produced by the
regasification unit 234 via gaseous natural gas fluidic coupling
246 and one or more control valves 250. In this manner, the
regasification unit supplies gaseous natural gas to the reservoir
218 to, for example, maintain the reservoir at a desired storage
level.
[0046] In another non-limiting example and as depicted in FIG. 2,
gaseous natural gas is also supplied directly from the
regasification unit 234 to the on-board engine 216 via gaseous
natural gas fluidic coupling 246, control valve 250, and fluidic
coupling 252. Advantageously, this configuration enables the
on-board engine 216 to operate using gaseous natural gas from the
regasification unit 234 independently from, or in combination with,
gaseous natural gas from the reservoir 218. In another non-limiting
example where gaseous natural gas is supplied directly from the
regasification unit 234 to the on-board engine 216, a reservoir
(such as reservoir 218) may not be utilized. In such a
configuration, boil-off gas is routed directly to the on-board
engine 216, and a separate starting mechanism (not shown) is
utilized to start the on-board engine.
[0047] In another non-limiting embodiment, the on-board engine 216
is further configured to generate electricity that is delivered to
one or more components on board the fuel tender 110 and/or on board
the locomotive 100. In one example, as depicted in FIG. 2, the
on-board engine 216 generates torque that is transmitted to a power
conversion unit 254 via drive shaft 258. The power conversion unit
254 is configured to convert the torque into electrical energy that
is delivered via electrical bus 256 to a variety of downstream
electrical components in the fuel tender 110. Such components may
include, but are not limited to, the regasification unit 234,
tender controller 220, control valves 230, 232, 244, 248, and 250,
LNG tank pressure sensor 260, LNG tank temperature sensor 264,
cryogenic unit 268, batteries 272, flow meters, heating fluid
temperature and pressure sensors, ambient air temperature sensors,
compressors, blowers, radiators, batteries, lights, on-board
monitoring systems, displays, climate controls (not shown), and the
like. Additionally, in some examples and in another advantage that
may be realized in the practice of some embodiments disclosed
herein, electrical energy from electrical bus 256 may be provided
to one or more components of the first locomotive 100, as described
in more detail below.
[0048] In one example the power conversion unit 254 includes an
alternator (not shown) that is connected in series to one or more
rectifiers (not shown) that convert the alternator's AC electrical
output to DC electrical power prior to transmission along the
electrical bus 256. Based on the configuration of a downstream
electrical component receiving power from the electrical bus 256,
one or more inverters may be configured to invert the electrical
power from the electrical bus prior to supplying electrical power
to the downstream component. In one example, a single inverter may
supply AC electrical power from a DC electrical bus to a plurality
of components. In another non-limiting embodiment, each of a
plurality of distinct inverters may supply electrical power to a
distinct component.
[0049] In some situations, the first locomotive 100 may be shifted
to a shut-down mode after a specified period of engine operation
and/or based on one or more engine operating conditions. In one
example, an AESS routine may include monitoring of a plurality of
locomotive operating parameters to verify that the operating
parameters are at a desired condition. If the AESS criteria are met
and the primary engine 118 is running, the engine may then be
automatically shut down. In this manner, by reducing the idling
time of the primary engine 118, fuel economy and reduced emission
benefits may be achieved.
[0050] During shut-down conditions, it may be desirable to continue
operating electronics on board the locomotive, such as an on-board
locomotive monitoring system, electronics control system 134
including first locomotive controller 136, and/or other locomotive
components. For example, during locomotive shut-down conditions a
plurality of engine operating parameters may be monitored, and the
engine may be automatically started in response to any of the
plurality of monitored locomotive operating conditions falling
outside a respective desired condition. Accordingly, in one
non-limiting embodiment, the power conversion unit 254 of the fuel
tender 110 provides electrical power via electrical bus 256 to the
first locomotive 100. Such electrical power may be used, for
example, to power an on-board locomotive monitoring system, operate
the electronics control system 134 including first locomotive
controller 136, charge batteries 148 and/or power other components
on board the first locomotive. Advantageously, by utilizing power
provided by the fuel tender 110, the first locomotive 100 may be
maintained in a shut-down condition while continuing to operate
electronic components on board the first locomotive. Accordingly,
the amount of idling time of the primary engine 118 may be reduced
and the locomotive system efficiency may be correspondingly
increased.
[0051] Tender controller 220 on board the fuel tender 110 controls
various components on board the fuel tender 110, such as the
regasification unit 234, on-board engine 216, power conversion unit
254, cryogenic unit 268, control valves, and/or other components on
board the fuel tender 110, by sending commands to such components.
On-board tender controller 220 may also monitor fuel tender
operating parameters in active operation, idle and shutdown states.
Such parameters may include, but are not limited to, pressure and
temperature of the LNG storage tank 212, pressure and temperature
of the regasification unit 234, on-board engine 216 temperature,
pressure, and load, compressor pressure, heating fluid temperature
and pressure, ambient air temperature, and the like. In one
example, computer readable storage media configured in the on-board
tender controller 220 may execute code to auto-stop, auto-start,
operate and/or tune the on-board engine 216 and regasification unit
234 in response to one or more control system routines. The
computer readable storage media may also execute code to transmit
to and receive communications from first locomotive controller 136
on board the first locomotive 100 and/or second locomotive
controller 194 on board the second locomotive 104.
[0052] It will be appreciated that the fuel tender 110 is not
limited to the components shown in the example of FIG. 2 and
described above. In other examples, the fuel tender 110 may include
additional or alternative components. As an example, the fuel
tender may further include one or more additional sensors, flow
meters, control valves, or the like.
[0053] The system of FIGS. 1-2 provide for a system of mechanically
coupled rail vehicles, comprising a first rail vehicle having a
first multi-fuel engine configured to fluidly couple to a tender,
wherein the tender includes a fuel container containing liquefied
natural gas, a regasification unit, and an on-board engine; a
second rail vehicle having a second multi-fuel engine configured to
fluidly couple to the tender; and a controller on board the first
rail vehicle, the controller configured to request gaseous natural
gas from the regasification unit and, responsive to receiving the
gaseous natural gas at the first multi-fuel engine, a portion of
the gaseous natural gas is sent to the second multi-fuel
engine.
[0054] The regasification unit is fluidly coupled to the fuel
container, is configured to receive the liquefied natural gas from
the fuel container, and is further configured to vaporize the
liquefied natural gas to gaseous natural gas via heat from a heated
thermal fluid. The tender further includes a reservoir fluidly
coupled to the regasification unit and to the on-board engine, the
reservoir coupled to receive a portion of the gaseous natural gas
from the regasification unit and to deliver the portion of the
gaseous natural gas to the on-board engine for powering the
on-board engine. The on-board engine is electrically connected to
an electronic component on board the tender for providing power to
the electronic component. In one example, the electronic component
comprises one or more of the regasification unit or a cryogenic
unit, wherein the cryogenic unit is configured to maintain the
liquefied natural gas in the fuel container in a liquid phase.
[0055] The system further comprises one or more electrical energy
lines that electrically connect the on-board engine to an
electronic component on board the first rail vehicle and are
configurable to provide power to the electronic component. The
system further comprises one or more fuel lines fluidly connecting
the regasification unit to the first rail vehicle. The one or more
fuel lines are configurable to deliver gaseous natural gas from the
regasification unit to the first rail vehicle.
[0056] Turning now to FIG. 3, an embodiment of a method 300 is
illustrated for receiving fuel for use by a first vehicle. In one
example, the first vehicle is a rail vehicle such as a locomotive.
Fuel may be stored in a remote liquid fuel container. For example,
the remote liquid fuel container may be located off-board the rail
vehicle. Further, a regasification unit may convert the liquid fuel
from the fuel container to a second, gaseous phase. As discussed
above, in one example, the liquid fuel is LNG and the second phase
of the LNG is gaseous natural gas (CNG). The regasification unit
may receive heated thermal transfer fluid (e.g., water, coolant, or
gas) from an engine. Additionally, the engine may use CNG to power
the engine and produce electricity which may then be supplied to
components on the first vehicle, the regasification unit, or other
components. In one example, the liquid fuel container is the LNG
storage tank 212 shown in FIG. 2 and the liquid fuel container is
located on a fuel tender (e.g., fuel tender 110 shown in FIG. 2).
As such, the fuel tender is mechanically coupleable to the
locomotive (e.g., first vehicle). Further, in this example, the
engine (e.g., on-board engine 215 shown in FIG. 2) and the
regasification unit (e.g., regasification unit 234 shown in FIG. 2)
are also located on the fuel tender. Advantageously, the method 300
enables heated fluid used for regasification to be generated on
board the fuel tender, which obviates the need for supplying heated
fluid from an external source, such as a locomotive (e.g., first
rail vehicle). The following description of method 300 and other
methods described below is provided with reference to the
components and configuration of the exemplary fuel tender 110 and
first locomotive 100 described above and shown in FIG. 2. It will
be appreciated that method 300 and the other methods described
below may also be performed in other contexts and environments
using other suitable components and configurations.
[0057] At 302, the method 300 includes sending a request (e.g., a
first request) from a first vehicle to a remote liquid fuel
container to convert a portion of the fuel in the container that is
in a first, liquid phase to a second, gaseous phase. As discussed
above, the fuel may be natural gas and the first, liquid phase may
include LNG and the second, gaseous phase may include CNG. Further,
in one example, the first vehicle is a locomotive and the request
is sent from the locomotive to a fuel tender mechanically
coupleable to the locomotive. Thus, the remote liquid fuel
container may be housed in the fuel tender. At 304, the method 300
includes delivering the fuel in the first, liquid phase from the
liquid fuel container to a regasification unit. In one example,
both the liquid fuel container and the regasification unit are on
board the fuel tender.
[0058] At 306, the method 300 includes heating thermal transfer
fluid using an engine and subsequently delivering the thermal
transfer fluid to the regasification unit. In one example, the
thermal transfer fluid includes one or more of coolant, water, and
air. Further, in one example, the engine is an on-board engine
included on the fuel tender. At 308, the method 300 includes
sending a request (e.g., a second request) to deliver a portion of
the fuel from the liquid fuel container in the second, gaseous
phase to the engine to fuel (e.g., power) the engine. In one
example, the portion of the fuel in the second, gaseous phase that
fuels the engine is boil-off gas from the liquid fuel container. In
one example, the liquid fuel container is the LNG storage tank 212
shown in FIG. 2. As shown in FIG. 2, the LNG storage tank 212 is
fluidly coupled directly to the on-board engine 216.
[0059] At 310, the method 300 includes requesting delivery of a
portion of the fuel in the second, gaseous phase from the
regasification unit to a reservoir and subsequently delivering the
portion of the fuel in the second, gaseous phase from the reservoir
to the engine to fuel (e.g., power) the engine. As noted above,
this configuration enables the reservoir 218 to maintain a
threshold amount of gaseous natural gas that may be used to start
and/or operate the on-board engine 216. As shown at FIG. 2, the
reservoir 218 is fluidly coupled to the regasification unit 234 and
receives gas from the unit. In some examples, the reservoir 218
also receives boil-off gas from the LNG storage tank 212 in
addition to receiving gas from the regasification unit 234. In an
alternate embodiment, the reservoir 218 may receive boil-off gas
from the LNG storage tank 212 instead of receiving gas from the
regasification unit 234.
[0060] In one example, the methods at 308 and 310 may occur
simultaneously. For example, the first locomotive controller 136
may send a request to deliver a portion of the fuel from the liquid
fuel container in the second, gaseous phase to the engine to fuel
the engine while also sending a request (e.g., requesting delivery)
to deliver a portion of the fuel in the second, gaseous phase from
the regasification unit to a reservoir and then the engine to fuel
the engine. In this way, the engine on board the fuel tender may be
powered by both the above gaseous natural gas sources. In another
example, only one of the methods at 308 and 310 may occur depending
on engine operating conditions. For example, if a volume of the
reservoir is low, fuel in the second phase may be delivered from
the liquid fuel container to the engine. In another example, if no
boil-off gas is present in the liquid fuel container, the fuel in
the second phase may be delivered from the reservoir to the engine.
In yet another example, the method at 310 may be modified such that
fuel in the second phase is delivered directly from the
regasification unit to the engine, thereby bypassing the
reservoir.
[0061] In this way, two or more sources that may supply gaseous
natural gas to the on-board engine 216 of the fuel tender 110. By
providing multiple sources of gaseous natural gas, supply between
or among the sources may be coordinated. In this manner, an
advantage that may be realized in the practice of some embodiments
is that the on-board engine 216 may utilize a variety of operating
routines that may provide, for example, a ready supply of gaseous
natural gas for use in starting the on-board engine 216, a backup
supply of gaseous natural gas that may be used when a primary
supply is empty or malfunctioning, or the like.
[0062] In some embodiments, a transition condition may trigger
switching from one gaseous natural gas source to another. Examples
of a transition condition include, but are not limited to, a fuel
level or amount in the first source falling below or exceeding a
threshold value, a pressure in the liquid fuel container,
reservoir, or regasification unit falling below or exceeding a
threshold value, a temperature in the liquid fuel container,
reservoir, or regasification unit falling below or exceeding a
threshold value, a load experienced by the on-board engine 216
falling below or exceeding a threshold value, a flow rate of LNG
and/or gaseous natural gas falling below or exceeding a threshold
value, or the like.
[0063] Returning to method 300, at 312, the method includes
requesting electricity generation using the engine and then
receiving the electricity at a first electronic component on board
the first vehicle. In one example, the first vehicle is the first
locomotive 100 shown in FIG. 2, and the first electronic components
on board the first locomotive include one or more of compressors
140, blowers 144, batteries 148, an electronics control system 134
comprising one or more controllers 136, shutoff valves, pressure
regulators, radiators, lights, on-board monitoring systems,
displays, climate controls (not shown), and the like.
[0064] At 314, the method 300 includes sending a request (e.g., a
third request) to deliver electricity to a second electronic
component. In one example, the second electronic component includes
one or both of the regasification unit and a cryogenic unit (such
as cryogenic unit 268 shown in FIG. 2). As discussed above, the
cryogenic unit is configured to maintain the liquid fuel container
in the first, liquid phase. As noted above and depicted in FIG. 1,
components receiving the generated electricity may also include,
but are not limited to, tender controller 220, control valves 230,
232, 244, 248, and 250, LNG tank pressure sensor 260, LNG tank
temperature sensor 264, flow meters, heating fluid temperature and
pressure sensors, ambient air temperature sensors, compressors,
blowers, radiators, batteries, lights, on-board monitoring systems,
displays, climate controls (not shown), and the like.
[0065] Turning now to FIG. 4, another embodiment relates to a
method 400 for a rail vehicle system including a source of gaseous
natural gas. In one example, the source of gaseous natural gas is a
fuel tender coupled to a first rail vehicle, such as fuel tender
110 shown in FIG. 2. In this example, the first rail vehicle
includes the first locomotive 100 shown in FIG. 2. Specifically,
the source of gaseous natural gas includes gaseous natural gas
produced by a regasification unit, such as the regasification unit
234 shown in FIG. 2. As discussed above, the regasification unit
converts LNG from a LNG storage container to gaseous natural gas
(CNG) using heated fluid provided and generated by an engine on
board the fuel tender. More specifically, in one example, the first
rail vehicle described above is coupled to the second rail vehicle
in a consist, and the source of the gaseous natural gas comprises:
a fuel tender coupled to the first and second rail vehicles in the
consist; or a regasification unit located on board the first rail
vehicle that receives liquefied natural gas from the fuel tender
for conversion to the gaseous natural gas.
[0066] At 402, the method 400 includes routing a first portion of
the gaseous natural gas to a first engine of a first rail vehicle.
In one example, the first rail vehicle is the first locomotive 100
and the first engine is the primary engine 118 shown in FIG. 2. As
noted above, the first locomotive controller 136 on board the first
locomotive 100 may monitor operating conditions of the primary
engine 118, and may transmit a request to tender controller 220 on
board the fuel tender 110 for gaseous natural gas. As a result, the
first portion of gaseous natural gas may be routed to the primary
engine 118. At 404, the method includes routing a second portion of
the gaseous natural gas to a second engine of a second rail
vehicle. In one example, the second rail vehicle is the second
locomotive 104 shown in FIG. 1. Routing the second portion of the
gaseous natural gas may include routing the gas through a pass
through fluidic coupling 160 to a natural gas-fueled engine on
board the second locomotive 104. In some embodiments, both the
engine on board the second locomotive 104 and the primary engine
118 are multi-fuel engines.
[0067] At 406, the method 400 includes operating an engine on board
a fuel tender to generate heated fluid. As discussed above, the
engine on board the fuel tender may provide the generated heated
fluid to a regasification unit on board the fuel tender. Thus, at
408, the method 400 includes sending a request to operate the
regasification unit on board the fuel tender to convert liquefied
natural gas to gaseous natural gas using the heated fluid. In one
example, the method at 402 may include adjusting a valve, such as
valve 232, to meter the gaseous natural gas produced at the
regasification unit to the first locomotive 100. In another
example, the method at 404 may include adjusting a valve, such as
valve 156, to meter gaseous natural gas produced at the
regasification unit to the second locomotive 104.
[0068] With reference now to FIG. 5, another embodiment relates to
a method 500 for maintaining a rail vehicle, such as a locomotive,
including an engine. In one example, the locomotive engine may be
stopped to enter a shutdown mode. Electricity for powering one or
more auxiliary loads on board the locomotive, normally generated by
the locomotive engine, may be supplied by an engine on board a fuel
tender. In this manner, an advantage that may be realized in the
practice of some embodiments is that the locomotive engine may be
maintained in a shutdown mode for an extended period, while also
receiving electricity to power auxiliary loads and components on
board the locomotive from an engine on board the fuel tender.
Accordingly, by facilitating idle time reduction of the locomotive
engine, fuel economy and reduced emissions benefits may be
achieved.
[0069] At 502 the method 500 includes receiving natural gas at an
engine on board a rail vehicle during engine operation. In one
example, the rail vehicle is the first locomotive 100 and the
engine is the primary engine 118 shown in FIG. 2. As discussed
above, the engine may be a multi-fuel engine using natural gas,
diesel, and/or other fuels. Also as discussed above with reference
to FIGS. 1-4, the engine may receive gaseous natural gas from a
fuel tender, the fuel tender including a regasification unit for
producing the gaseous natural gas.
[0070] At 504 the method 500 includes signaling the engine on board
the rail vehicle to enter a shutdown mode. In one example,
signaling the engine includes sending a signal or request from a
controller on board the rail to the engine. In response to the
engine shutdown request, the method 500 includes stopping the
engine at 506.
[0071] At 508 the method 500 includes sending a request off board
the rail vehicle to supply natural gas to a natural gas-fueled
engine. The method further includes operating a natural gas-fueled
engine to generate electrical energy. In one example, the natural
gas-fueled engine is off board the rail vehicle and may be referred
to as an off board engine.
[0072] In another example, the natural gas-fueled engine is off
board the rail vehicle and on board a fuel tender. In this example,
the natural gas-fueled engine is the on-board engine 216, on board
the fuel tender 110, as shown in FIG. 2. In this example, sending
the request at 508 includes sending the request to the fuel tender
to supply natural gas to the natural gas-fueled engine. In another
example, the request sent at 508 includes sending, or transmitting,
a request for electricity generation to the natural gas-fueled
engine. As discussed above, the natural gas-fueled engine is
fluidly coupled to one or more fuel sources.
[0073] In a first example, sending the request at 508 includes
sending a request to deliver gaseous natural gas from a
regasification unit on board the fuel tender to the natural
gas-fueled engine at 510. The natural gas-fueled engine then
generates electricity by powering the natural gas-fueled engine
with the gaseous natural gas received from the regasification unit.
In a second example, sending the request at 508 includes sending a
request to deliver gaseous natural gas from a reservoir on board
the fuel tender to the natural gas-fueled engine at 512. The
natural gas-fueled engine then generates electricity by powering
the natural gas-fueled engine with the gaseous natural gas received
from the reservoir. In a third example, the request at 508 includes
sending a request to deliver boil-off gas from liquefied natural
gas being stored in the fuel tender to the natural gas-fueled
engine at 514. The natural gas-fueled engine then generates
electricity by powering the natural gas-fueled engine with boil-off
gas from liquefied natural gas. In one example, the liquefied
natural gas is stored in a LNG storage tank, such as the LNG
storage tank 212 shown in FIG. 2, and the boil-off gases come from
the LNG storage tank.
[0074] At 516 the method 500 includes receiving electrical energy
from off board the rail vehicle to power the rail vehicle for at
least a period while the engine is stopped. In one example, off
board the rail vehicle includes the fuel tender and the electrical
energy is received from the natural gas-fueled engine on board the
fuel tender. Specifically, receiving the electrical energy includes
receiving at least a portion of the electrical energy generated by
the natural gas-fueled engine. The method at 516 further includes
powering one or more auxiliary loads or electronic components on
board the rail vehicle (e.g., first locomotive 100 shown in FIG. 2)
with at least the portion of electrical energy received from the
fuel tender. The one or more auxiliary loads or electronic
components include at least one or more of a compressor, a blower,
a battery, a traction motor, a compressed air unit, a radiator fan,
an electronic control system, a lighting system, a sensor, a
communication system, safety equipment (e.g., a positive train
control or collision avoidance system), an energy storage unit, and
a controller. Further, the method at 516 may include maintaining an
electronic control system of the rail vehicle in an active state
during the shutdown mode.
[0075] At 518 the method 500 includes powering one or more
electronic components on board the fuel tender with at least a
portion of the electrical energy generated by the natural
gas-fueled engine. The one or more electronic components include
one or more of the regasification unit and a cryogenic unit. The
electronic components may also include a controller, valve, sensor,
or the like, on board the fuel tender.
[0076] In this way, an embodiment relates to a method comprising
receiving natural gas at an engine on board a first rail vehicle
during engine operation, stopping the engine in response to an
engine shutdown request, and receiving electrical energy from off
board the first rail vehicle to power the first rail vehicle for at
least a period while the engine is stopped. In another embodiment,
the engine shutdown request is an automatic engine shutdown request
initiated onboard the first rail vehicle, and the electrical energy
is received from a second rail vehicle coupled to the first rail
vehicle. (The automatic engine shutdown request may result
responsive to the occurrence of one or more designated operational
criteria of the rail vehicle, and does not include the situation of
an operator of the rail vehicle turning the vehicle off.) In
another embodiment, the second rail vehicle is a fuel tender car,
and the electrical energy is generated by an on board engine of the
fuel tender car, which is powered by natural gas carried by the
fuel tender car.
[0077] With reference now to FIG. 6, a method 600 for maintaining a
rail vehicle in response to various engine condition signals is
presented. The method 600 includes sending engine condition signals
from a rail vehicle to a fuel tender coupled to the rail vehicle.
Based on the engine condition signals, components on board the fuel
tender maybe operated to generate gaseous natural gas and/or
generate electrical energy which may then be supplied to the rail
vehicle. In one example, the rail vehicle is the first locomotive
100 and the fuel tender is the fuel tender 110 shown in FIGS.
1-2.
[0078] At 602 the method 600 includes sending an engine condition
signal from the rail vehicle to the fuel tender coupled to the rail
vehicle. In one example, at 604 the engine condition signal
indicates an engine shutdown request. For example, the engine
shutdown request may correspond to shutting down the primary engine
118 of the first locomotive shown in FIG. 2. In another example, at
606 the engine condition signal indicates an engine load. For
example, the engine load may be an engine load experienced by the
dual or multi fuel primary engine 118 of the first locomotive 100.
In yet another example, at 608 the engine condition signal
indicates a ratio of gaseous natural gas to alternate fuel. As
noted above, in one example the primary engine 118 may comprise a
multi fuel engine that utilizes gaseous natural gas and an
alternate fuel, such as diesel fuel, for combustion. The primary
engine 118 may operate using ratios of gaseous natural gas and the
alternate fuel that may vary depending upon one or more engine
conditions. Accordingly, in some examples the electronics control
system 134 may communicate to the fuel tender 110 a desired ratio
of gaseous natural gas to alternate fuel. Thus, in some examples,
the method at 608 includes adjusting the ratio of diesel fuel to
gaseous natural gas. Other engine condition signals that may be
received in other examples include, but are not limited to,
manifold air temperature (MAT), ambient air temperature, engine oil
temperature, compressor air pressure, main air reserve pressure,
battery voltage, a battery state of charge, brake cylinder
pressure, or the like.
[0079] At 610 the method 600 includes requesting the natural
gas-fueled engine to start based at least in part on receiving the
engine condition signal. At 612 the method 600 includes taking
action based on the engine condition signal. In one example, in
response to an engine shutdown signal, or other engine condition
signal, the method at 614 includes powering at least one auxiliary
load on board the rail vehicle with electrical energy received from
the natural gas-fueled engine. The at least one auxiliary load
includes one or more of an electronics control system, a blower, a
traction motor, a compressed air unit, a radiator fan, a lighting
system, a collision avoidance or positive train control system,
safety equipment, communication equipment, a sensor, and an energy
storage unit.
[0080] In another example, in response to the engine condition
signal, the method at 616 includes powering at least one electrical
load off board the rail vehicle. The powering the at least one
electrical load off board the rail vehicle includes at least one of
electrically heating a regasification unit and cryogenically
maintaining liquefied natural gas. For example, in response to the
engine condition, the cryogenic unit 268 and/or the on-board engine
216 may be powered. Further, the regasification unit may also be
powered at 616.
[0081] In yet another example, in response to the engine condition
signal, the method at 618 includes consuming gaseous natural gas at
a multi-fuel engine of the rail vehicle (e.g., the primary engine
118 of the first locomotive 100). The method at 618 may further
include heating thermal fluid using the natural gas-fueled engine
and regasifying liquefied natural gas to form the gaseous natural
gas using the heated thermal fluid. In some examples, the actions
at 618 may be in response to the engine condition signal indicating
an increased engine load and/or a larger ratio of gaseous natural
gas to alternate fuel.
[0082] In this way, in an embodiment, a method comprises sending an
engine condition signal from a rail vehicle to a fuel tender
coupled to the rail vehicle, requesting a natural gas-fueled engine
to start based at least in part on receiving the engine condition
signal, and powering at least one auxiliary load on board the rail
vehicle with electrical energy received from the natural gas-fueled
engine. In another embodiment, the natural gas-fueled engine is on
board the fuel tender vehicle.
[0083] In an embodiment, the on-board engine 216 may be started in
response to an LNG tank 212 condition signal received by the tender
controller 220. The LNG tank 212 condition signal may comprise, for
example, a pressure, temperature, LNG amount or level, or boil-off
gas amount or level. In one example, the pressure in the LNG tank
212 may be detected to exceed a predetermined threshold. If the
on-board engine 216 is not operating, the on-board engine may be
started and boil-off gas may be released from the LNG tank 212 and
delivered via fluidic coupling 242 to the on-board engine.
Advantageously, in this manner the on-board engine 216 may function
as a pressure-relief mechanism to maintain the LNG tank 212 at or
below a desired pressure. It will also be appreciated that in some
examples the electricity generated by the on-board engine 216 may
be stored in energy storage devices, such as batteries 272 on board
the fuel tender and/or batteries 148 on board the first locomotive
100.
[0084] In an embodiment, the on-board engine 216 of the fuel tender
110 may comprise an air-cooled combustion engine that supplies
heated air via fluidic coupling 240 to the regasification unit 234
for use in vaporizing LNG to gaseous natural gas. In other
embodiments, such as in any of the other embodiments described
herein, the on-board engine 216 of the fuel tender 110 may comprise
a water-cooled combustion engine that supplies heated water via
fluidic coupling 238 to the regasification unit 234 for use in
vaporizing LNG to gaseous natural gas. In still other embodiments,
such as in any of the other embodiments described herein, the
on-board engine 216 of the fuel tender 110 may comprise a
water-cooled combustion engine that supplies both heated water and
heated air via fluidic couplings 238 and 240, respectively, to the
regasification unit 234 for use in vaporizing LNG to gaseous
natural gas.
[0085] In an embodiment, the on-board engine 216 may be controlled
to only supply heated fluid to the regasification unit 234, and not
to generate torque that is transmitted to the power conversion unit
254. In one example, a clutch may disengage the drive shaft 258
from the on-board engine 216 such that the on-board engine output
is used solely to supply heated fluid to the regasification
unit.
[0086] In an embodiment, the on-board engine 216 may be controlled
to supply heated fluid to the regasification unit 234 and to
generate torque that is transmitted to a power conversion unit 254
via drive shaft 258. As noted above, the power conversion unit 254
is configured to convert the torque into electrical energy that is
delivered via electrical bus 256 to a variety of downstream
electrical components in the fuel tender 110. In one example, the
on-board engine 216 may be tuned to generate a maximum amount of
heated fluid such as, for example, via retarded spark timing. In
this manner, operation of the on-board engine 216 may be controlled
to enable the regasification unit 234 to vaporize and deliver a
maximum amount of gaseous natural gas to the first locomotive 100.
It will be appreciated that in this example, the amount of torque
imparted to the drive shaft 258 may be less than an amount of
torque that may be imparted via other tunings of the on-board
engine 216 that do not prioritize generation of heated fluid.
[0087] In another example, the on-board engine 216 may be tuned to
impart a maximum amount of torque to the drive shaft to generate a
corresponding maximum amount of electricity via the power
conversion unit 254. In this manner, operation of the on-board
engine 216 may be controlled to maximize the amount of electricity
delivered to various components on board the fuel tender 110 and/or
to components on board the first locomotive 100 and/or other rail
vehicles. It will be appreciated that in this example, the amount
of heated fluid generated by the on-board engine 216 may be less
than an amount of heated fluid that may be generated via other
tunings of the on-board engine 216 that do not prioritized
generation of electricity.
[0088] In an embodiment, the on-board engine 216 may receive
boil-off gas from the storage tank 212. The boil-off gas may power
the on-board engine to generate electricity, even when such
electricity may not be used by an on-board or off-board load. The
electricity may then be dissipated in a resistive grid as heat, or
may be stored in batteries 272 on board the fuel tender 110,
batteries 148 on board the locomotive 100, or other batteries
off-board the fuel tender. In this manner, venting of the boil-off
gas to atmosphere may be avoided, and additional energy storage in
batteries may also be realized. More specifically, in at least one
mode of operation where the on-board engine 216 is operational
(that is, functional), the on-board engine receives all the
boil-off gas from the storage tank 212, and in effect converts the
boil-off gas (through combustion) into electricity, which is used
to power loads and/or stored in batteries, and with any excess
generated electricity being dissipated in one or more resistive
grids as heat, such that no boil-off gas is vented to atmosphere.
The one or more resistive grids may be on board the tender, and/or
resistive grids on rail vehicles coupled to the tender may be
utilized for this purpose. A mode of operation may be provided
wherein the boil-off gas is vented to atmosphere if the on-board
engine 216 is nonfunctional (e.g., a safety valve that triggers, to
vent the boil-off gas to atmosphere, when a pressure of the
boil-off gas exceeds an operational pressure threshold of the
safety valve, wherein when the on-board engine is functioning
properly, the pressure of the boil-off gas is kept below the
operational pressure threshold of the safety valve). Thus, in an
embodiment, a method comprises, in a fuel tender vehicle,
combusting all boil-off gas of a liquid fuel reservoir of the fuel
vehicle in an on-board engine of the fuel tender when the on-board
engine is not malfunctioning, and venting the boil-off gas to
atmosphere when the on-board engine is malfunctioning. In another
embodiment, a method comprises, in a fuel tender vehicle,
combusting all boil-off gas of a liquid fuel reservoir of the fuel
vehicle in an on-board engine of the fuel tender when the on-board
engine is not malfunctioning, and, when the on-board engine is
malfunctioning, storing the boil-off gas in a second reservoir and
venting the boil-off gas to atmosphere when the second reservoir is
full.
[0089] In another embodiment, the primary engine 118 of the first
locomotive 100 may comprise a single fuel engine that is powered by
gaseous natural gas received from the fuel tender 110.
[0090] In this written description, references to "one embodiment"
or "an 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," or the like. are used merely as labels, and are not
intended to impose numerical requirements or a particular
positional order on their objects.
[0091] 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.
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