Patent Application
20140033943
The present disclosure relates generally to a fuel distribution system and, more particularly, to a fuel distribution system for a multi-locomotive consist.
Natural gas has been used as fuel for internal combustion engines in consist locomotives. Because natural gas has a lower volumetric energy density than traditional fuels, such as diesel and gasoline, the natural gas used by the locomotives is generally only practical to store in a liquefied state (“LNG”). At atmospheric pressures, the natural gas must be chilled to below about −160° C. to remain in liquid form. Consists having LNG-fueled locomotives store the LNG in insulated tank cars (a.k.a., tender cars) that are towed by the locomotive. An exemplary consist having an LNG-fueled locomotive coupled with a dedicated tender car is disclosed in U.S. Pat. No. 6,408,766 of McLaughlin that issued on Jun. 25, 2002.
Although the conventional method of coupling a dedicated tender car to a single locomotive helps to ensure an adequate supply of fuel for most travel routes, it can also be cumbersome and expensive, while also decreasing an efficiency of a consist. In particular, when multiple locomotives are required to pull a consist, the extra tender cars (one per locomotive) increase a component cost, operating cost, and maintenance cost, and operating complexity of the consist. In addition, the extra tender cars increase an overall weight of the consist and a required capacity and fuel consumption of the locomotives.
The system of the present disclosure solves one or more of the problems set forth above and/or other problems with existing technologies.
In one aspect, the disclosure is directed to a fuel distribution system for a consist. The fuel distribution system may include a first locomotive, a second locomotive, and a tender car. The fuel distribution system may also include at least one pump located onboard the tender car, and at least one fluid conduit attached to the at least one pump. The at least one fluid conduit may be configured to deliver gaseous fuel from the tender car to the first and second locomotives.
In another aspect, the disclosure is directed to a method of distributing fuel to a consist. The method may include pumping liquefied gaseous fuel from a tender car, and vaporizing the liquefied gaseous fuel. The method may also include directing the resulting gaseous fuel to a first locomotive and a second locomotive of the consist.
Locomotive 10 may include a car body 12 supported at opposing ends by a plurality of trucks 14 (e.g., two trucks 14). Each truck 14 may be configured to engage a track 16 via a plurality of wheels 17, and support a frame 18 of car body 12. Any number of main engines 20 may be mounted to frame 18 and configured to produce electricity that drives wheels 17 included within each truck 14. In the exemplary embodiment shown in
Main engine 20 may be a large engine, for example an engine having sixteen cylinders and a rated power output of about 4,000 brake horsepower (bhp). Main engine 20 may be configured to combust a gaseous fuel, such as natural gas, and generate a mechanical output that drives a main generator 21 to produce electric power. The electric power from main generator 21 may be used to propel locomotive 10 via one or more traction motors 32 associated with wheels 17 and, in some instances, directed to one or more auxiliary loads 43 of consist 13 (e.g., lights, heaters, refrigeration devices, air conditioners, fans, etc.). A switch 23 (shown only in
Main generator 21 may be an induction generator, a permanent-magnet generator, a synchronous generator, or a switched-reluctance. In one embodiment, main generator 21 may include multiple pairings of poles (not shown), each pairing having three phases arranged on a circumference of a stator (not shown) to produce an alternating current.
Traction motors 32, in addition to providing the propelling force of consist 13 when supplied with electric power, may also function to slow locomotive 10. This process is known in the art as dynamic braking. When a traction motor 32 is not needed to provide motivating force, it can be reconfigured to operate as a generator. As such, traction motors 32 may convert the kinetic energy of consist 13 into electric energy, which has the effect of slowing consist 13. The electric energy generated during dynamic braking is typically transferred to one or more resistance grids 60 mounted on car body 12. At resistance grids 60, the electric energy generated during dynamic braking is converted to heat and dissipated into the atmosphere. Alternatively or additionally, electric energy generated from dynamic braking may be routed to an energy storage system 19 used to selectively provide supplemental power to traction motors 32.
Tender car 11 may be provided with an auxiliary engine 36 that is mechanically connected to an auxiliary generator 38 (shown only in
Auxiliary engine 36 may be smaller and have a lower rated output than main engine 20. For example, auxiliary engine 36 may have six to twelve cylinders and a rated power output of about 400-1400 bhp. It should be noted, however, that engines with a different number of cylinders or rated power output may alternatively be utilized, if desired. Similar to main engine 20, auxiliary engine 36 may combust natural gas or another type of gaseous fuel to generate a mechanical output used to rotate auxiliary generator 38. Auxiliary generator 38 may produce an auxiliary supply of electric power directed to one or more of the auxiliary loads 43 (i.e., loads not driven by main engine 20) of consist 13.
Auxiliary generator 38, in addition to providing electric power to auxiliary loads 43 of locomotive 10 or to the other cars of consist 13, may also provide electric power to one or more traction motors 32 on tender car 11, if desired. Similar to traction motors 32 located on locomotive 10, traction motors 32 of tender car 11 may function to propel tender car 11 by rotating wheels 30. In this manner, tender car 11 may be self-propelled and capable of moving about on its own power, independent of locomotive 10 or any other car (when uncoupled from locomotive 10 and the other cars).
Similar to locomotive 10, tender car 11 may generate its own electric energy via dynamic braking via traction motors 32. The generated electric power may be stored at an electric energy storage system 51 onboard tender car 11. Energy stored within system 51 may be selectively provided to traction motors 32 of tender car 11, and/or to any auxiliary load 43 of consist 13.
Auxiliary generator 38 and/or energy storage system 51 of tender car 11 may provide electric power to auxiliary loads 43 on locomotive 10 via an electric conduit 50. With this configuration, main engine 20 may be capable of shutting down or otherwise functioning at a reduced-output level and auxiliary loads 43 may continue to function normally by utilizing power provided by auxiliary generator 38.
Tender car 11 may also include one or more tanks 24 configured to store a liquid fuel (e.g., LNG) for combustion within main engine 20 and auxiliary engine 36. In the disclosed embodiment, a single tank 24 is shown. Tank 24 may be an insulated, single or multi-walled tank configured to store the liquid fuel at low temperatures, such as below about −160° C. Tanks 24 may be integral with frame 18 of tender car 11.
A fuel delivery circuit 55 may supply fuel from tank 24 to main engine 20 on locomotive 10 and to auxiliary engine 36 on tender car 11. Fuel delivery circuit 55 may include, among other things, one or more fuel pumps 44, one or more conduits 48, one or more heat exchangers 46, one or more accumulators (e.g., a main accumulator 52 and an auxiliary accumulator 54), and one or more injectors (not shown) that condition, pressurize or otherwise transport low-temperature liquid fuel, as is known in the art. Fuel delivery circuit 55 may also include one or more regulators 47 that help to regulate flow between main and auxiliary accumulators 52, 54 and engines 20, 36, respectively.
As illustrated in
As illustrated in
Accumulators 52, 54 on locomotive 10 and tender car 11, may be configured to receive pressurized gaseous fuel. Accumulators 52, 54 may embody, for example, compressed gas, membrane/spring, bladder-type, or other suitable accumulators configured to collect pressurized gaseous fuel and discharge the fuel to main engine 20 or auxiliary engine 36 via regulator 47.
Regulators 47 may be configured to selectively allow fluid communication between accumulators 52, 54 and main and auxiliary engines 20, 36, respectively. When regulators 47 open, they may allow gaseous fuel to escape accumulators 52, 54 and flow to main and/or auxiliary engines 20, 36. Regulators 47 may each include a spring-loaded mechanism (not shown) that opens at a predetermined pressure to avoid over-pressurization of accumulators 52, 54. Additionally or alternatively, regulators 47 may each include one or more controllable actuators, such as one or more electric solenoids that are operable to open regulator 47 when actuated.
As illustrated in the simplified illustrations of
The disclosed fuel distribution system may be applicable to any consist 13 utilizing a low-temperature liquid fuel. The disclosed system may reduce a cost of consist 13, while also increasing a capacity and fuel consumption of the consist. In particular, the use of a single tender car 11 to fuel multiple locomotives reduces a component cost, operating cost, and maintenance cost of consist 13 simply by reducing a number of cars in consist 13. In addition, the reduction in the number of cars results in a weight reduction of consist 13 and a corresponding increase in the capacity of main engines 20 to pull consist 13 and a corresponding increase in fuel consumption.
It will be apparent to those skilled in the art that various modifications and variations can be made to the disclosed system without departing from the scope of the disclosure. Other embodiments of the system will be apparent to those skilled in the art from consideration of the specification and practice of the system disclosed herein. It is intended that the specification and examples be considered as exemplary only, with a true scope of the disclosure being indicated by the following claims and their equivalents.
