Patent Application
20150285264
1. Field
The present invention is generally related to a cooling system for an air compressor.
2. Description of Related Art
Using one or more locomotives in a train to move railroad freight or passenger cars is well known. Typically, locomotives are manufactured by companies such as Electro-Motive Diesel, Inc. (“EMD”) or General Electric (“GE”) to meet standardized designs, with only minor changes in details possible, if specified by the locomotive customer as a purchase requirement. Each locomotive may include a motor and air compressor for operation of an air brake system, for example. Such compressors may be water cooled. Air compressors on locomotives by EMD are typically cooled using recirculated water from an engine compartment or engine-based closed system. For example, an intercooler is provided on the air compressor and receives via internal passages the engine cooling water. Gardner Denver also produces examples of such air compressors that are cooled via engine coolant. Any thermal energy generated by air compression may be transferred to the engine coolant for release to the atmosphere through radiators.
Because existing air compressors on locomotives are typically cooled using recirculated engine coolant, temperatures of the engine coolant may increase, resulting in lower efficiency and temperature control, and possible lower performance of the air compressor.
It is an aspect of this disclosure to provide an air compressor with a self-contained, liquid-cooled cooling system.
Another aspect provides a closed-loop cooling system including an air compressor that includes at least one passage for a flow of coolant therethrough to cool its parts. At least one temperature sensor is located in the air compressor for measuring a temperature of the coolant. The system also includes a pump for pumping an input flow of coolant into at least one passage of the air compressor and a heat exchanger for cooling an output flow of coolant from at least one passage of the air compressor. A rate of flow of the coolant is based on the temperature of the coolant measured by at least one temperature sensor.
Another aspect provides a self-contained closed-loop cooling system for a vehicle. The system includes an air compressor operable to produce compressed air with at least one passage for flow of coolant therethrough, a pump for pumping an input flow of coolant into the at least one passage of the air compressor, and a heat exchanger for cooling an output flow of coolant from the at least one passage of the air compressor. The self-contained closed loop cooling system is independent of an engine cooling system of the vehicle.
Yet another aspect provides a locomotive. The locomotive includes an engine, an engine cooling system, and a self-contained air compressor system. The compressor system includes an air compressor operable to produce compressed air. The air compressor includes at least one passage for flow of coolant therethrough. The compressor system also includes a pump for pumping an input flow of coolant into the at least one passage of the air compressor, a heat exchanger for cooling an output flow of coolant from the at least one passage of the air compressor, and a plurality of fluid delivery lines connecting the air compressor, the pump, and the heat exchanger in a closed loop configuration for the flow of coolant therethrough. The self-contained air compressor system is separate and not coupled to the engine cooling system.
Still yet another aspect provides a method of controlling a temperature of an air compressor of a locomotive configured to receive and compress air from an air source. The air compressor has a passage for flow of coolant that is in closed communication with a pump and a heat exchanger. The method includes pumping coolant to the air compressor using the pump to deliver coolant to the air compressor; passing the flow of coolant through the passage of the air compressor; outputting coolant from the passage of the air compressor to the heat exchanger; removing heat from the coolant with the heat exchanger; and delivering the coolant from the heat exchanger to the pump for pumping. A temperature of the coolant in the passage is determined using at least one temperature sensor located in the air compressor, and a rate of flow of the coolant is based on the temperature of the coolant.
Other features and advantages of the present invention will become apparent from the following detailed description, the accompanying drawings, and the appended claims.
Aspects of this disclosure provide for the replacement of an existing air compressor cooling system that typically uses engine water coolant, with a self-contained, closed loop system that is separate from and is not coupled to the engine cooling system in a vehicle. The self-contained cooling system is independent of the engine cooling system. Various aspects of the disclosure provide for improvements in efficiency and temperature control, among other features, of the air compressor in a locomotive, thus resulting in performance optimization of the air compressor within the locomotive.
Referring now more particularly to the drawings,
The self-contained cooling system 200 is associated with and communicates solely with the air compressor 300 for flowing coolant through at least one passage 307 of the air compressor 300 for heat recovery to cool its parts. As the coolant or fluid circulates through the fluid circuit defined by the passage(s) 307, the temperature of the parts is cooled via heat transfer to the flowing coolant.
Throughout this disclosure, it should be understood that reference to the self-contained air compressor cooling system 200, or cooling system 200, refers to a system for an air compressor 300 of a locomotive 102. The cooling system 200 utilizes contained, circulating coolant for heat transfer and/or absorption of any thermal energy generated by the air compressor 300 for release to the atmosphere (e.g., through radiators), without connection to or use of engine coolant or other coolant feed. The herein disclosed cooling system 200 may also be integrated into a modular package. In an embodiment, the self-contained cooling system 200 for the air compressor 300 may be a retrofit system designed for connection to an existing air compressor in a locomotive, such that upon connection or installation to an air compressor, it may circulate coolant in a contained, closed loop, while being subjected to alternate cooling and heating, without use of the engine coolant or other system coolant feed (e.g., wherein any valve or connection with a flow of coolant from the engine cooling system is closed or disconnected upon retrofit of the cooling system 200 to the air compressor 300). The flow of coolant is distributed without contact to atmospheric or ambient air via fluid delivery lines, for example, through the cooling system 200.
The air compressor 300 receives and compresses air from an air source 208. Generally, the air source 208 may be ambient or atmospheric air. To operate the air compressor 300, a power source 304 is provided and is coupled to the air compressor 300 for driving the air compressor 300 to produce compressed air. The power source 304 may be provided in the locomotive 102, for example. The compressor 300 may be connected to the power source 304 via a drive shaft 303, for example, or the drive shaft 303 itself may be considered the power source 304. In an embodiment, the power source 304 is a motor or engine. An engine for driving the air compressor 300 may be the main power source for the locomotive 102, for example. In an embodiment, the engine may comprise the power source 304. That is, the air compressor 300 may be driven from the locomotive's engine (e.g., diesel engine) through drive shaft 303 and couplings. The engine may rotate the drive shaft 303 to drive various devices and systems needed to power the locomotive 102 (e.g., electricity generator or alternator to move the train), including the air compressor 300.
The air compressor 300 is operable to produce a flow of compressed air for locomotive applications. Air is supplied via an air intake line 305 from the air source 208 into an air inlet 306 (or inlets) of the air compressor 300 during operation. Air is compressed by the air compressor and the compressed air is output via an air outlet 308 (or outlets) and provided via a compressed air delivery line 309 to an associated system of the locomotive, e.g., to an air brake system 210, such as shown in
The air compressor 300 utilized in the example locomotive is not limited by type. In an embodiment, the air compressor is a two-stage, reciprocating type air compressor. In an embodiment, the air compressor has three stages of cylinders arranged in a pattern, with two low pressure cylinders and one high pressure cylinder. In an embodiment, the air compressor is a two stage, three cylinder W configuration as shown in
The air compressor 300 may act as a single stage air compressor. In an embodiment, the air compressor 300 is multi stage compressor.
In accordance with an embodiment, the air compressor 300 comprises an air compressor manufactured and/or distributed by Gardner Denver, including, but not limited to, three or four cylinder models.
The air compressor 300 may be a reciprocating compressor, rotary screw compressor, or a centrifugal compressor. The air compressor 300 may comprise any number of cylinders and pistons. The air compressor 300 may also include an intercooler assembly for reducing the temperature of the exiting or output compressed air. These and other parts of the compressor, e.g., crankcase, filters, pump, valves, gauges, etc. are understood by those of ordinary skill in the art, and thus are not explained in detail herein. Further, the movement and implementation of those parts, e.g., strokes of the cylinder, and any cycle of operation may not be described in detail herein, but are understood by one of ordinary skill in the art.
However, as an example, general operation of a two stage, three cylinder air compressor 300 may be understood as follows: atmospheric air is delivered from air intake filters of the air source 208 through an open inlet valve (at air inlet 306) of the air compressor 300 into the low pressure cylinders for compression. The air is cooled and is directed to the high pressure cylinder for further compression, via an intercooler (e.g., a radiator between the low and high pressure cylinders). The intercooler may include a jacket for the coolant passage. Then the compressed, pressurized air is directed or exhausted through an outlet valve (at air outlet 308) to reservoirs and delivered to the associated system via the output line 309 (e.g., in an air brake system 210, compressed air is directed to a reservoir for distribution to brake cylinders/pistons to develop mechanical brake power).
The air compressor 300 includes at least one passage 307 for a flow of coolant therethrough to cool its parts. Rather than receiving engine cooling water in its internal passages to cool its intercooler assembly, heat generated from the air being discharged from the cylinders is transferred to coolant circulating in the at least one passage 307, and is released to the atmosphere through fan 316 and/or heat exchanger 314, for example. The cooling of the compressor parts improves the volumetric efficiency of the air compressor 300. In an embodiment, the intercooler includes a fan which increases the cooling efficiency.
Fluid delivery lines 318, 324, and 330 connect the air compressor 300, the pump 312, and the heat exchanger 314 in a closed loop configuration for the flow of coolant therethrough. The flow of coolant may be distributed via the fluid delivery lines 318, 324, and 330 through the pump 312, heat exchanger 314, and air compressor 300 without contact to atmospheric/ambient air and without interaction to any cooling system for the engine of the locomotive. Reference to types of fluid delivery lines are not intended to be limited; the pump 312, air compressor 300, and heat exchanger 314 may be connected via pipes, tubes, and/or conduits, for example.
At least one controller 310 or a control system may be provided in the self-contained cooling system 200 for controlling and communicating with the associated parts, e.g., pump 312, heat exchanger 314, fan 316, and valve 334 along the fluid delivery lines 318, 324, and 330. The controller 310 may output and receive information and/or data associated with the cooling system 200, including the air compressor 300, as well as any number of other systems, including remote systems or devices not installed on the locomotive 102. The controller 310 may be a microcontroller or microprocessor, for example. Any reference to a controller 310 herein should be understood to correspond to a device or a system that may include one or more controllers or processors. As described later, the controller 310 may be used to control a rate of flow of the coolant throughout the fluid delivery lines 318, 324, and 330 and/or the at least one passage 307 of the compressor. For example, the controller 310 may be used to control rate of flow from the pump 312. The controller 310 may also be used to adjust the speed of the fan 316, for example. As also described later, the controller 310 may receive temperature related to the coolant from one or more temperature sensors 340, 342 provided in the air compressor 300. The temperature data may be used by the controller 310 to adjust operation of the cooling system 200. For example, the rate of flow of the coolant may be adjusted based on temperature data. Based on the temperature data, controller 310 may transmit one or more control signals to the pump 312 to vary the rate of flow provided by the pump 312.
The pump 312 pumps an input flow of coolant into the at least one passage 307 of the air compressor 300. As shown in
An optional control valve 334 may be provided on the input fluid delivery line 318 that is configured for movement (e.g., via control provided by the controller 310) between an open position, a closed position, and positions therebetween, to control (e.g., allow or limit or prevent) the amount or rate of input flow of the pumped coolant being delivered from or by the pump 312 to the at least one passage 307 of the air compressor 300, for example. Although only one coolant control valve is shown in
Operation of the pump 312 is generally known and thus not described in detail herein. The type of pump used in the cooling system 200 is not limiting. In an embodiment, the pump 312 is a 74 volt DC inverter driven pump.
The heat exchanger 314 cools an output flow of coolant received from the at least one passage 307 of the air compressor 300. The fluid delivery line 324 is an output line connected between a coolant outlet 322 of the air compressor 300 and an inlet 326 of the heat exchanger 314 for delivery of the output flow of coolant from the air compressor 300 to the heat exchanger for cooling.
The heat exchanger 314 is configured to cool the output flow of coolant as it runs through, so that the temperature of the coolant is decreased and may be used (pumped) again through the air compressor 300 for cooling. Since the process of compressing air may produce heat, the circulating coolant increases in temperature as the heat is transferred thereto. Thus, the output coolant is higher in temperature than the input coolant. Such heat may not only increase the temperature of the compressed air but also any fluids, such as oil, used for lubricating and sealing parts of the compressor. Accordingly, the heat exchanger is configured to receive the higher temperature output coolant downstream from the air compressor 300 to reduce the temperature of the coolant.
The fan 316 provides air flow through and/or across the heat exchanger 314. The fan 316 moves air across the heat exchanger 314, as shown by arrows 332 in
Operation of the heat exchanger 314 and fan 316 are generally known and thus not described in detail herein. The type of heat exchanger 314 or fan 316 used in the cooling system 200 is not limiting. In an embodiment, the fan 316 is a 74 volt DC inverter driven cooling fan. The heat exchanger 314 may be sized and/or configured based on heat rejection of the air compressor 300. The heat exchanger 314 may also use mechanically bonded tubes.
After coolant flows through the heat exchanger 314, it is delivered back to the pump 312. Fluid delivery line 330 is an intermediate line connected between the heat exchanger 314 and the pump 312 for delivery of the cooled output flow of coolant from the outlet 328 of the heat exchanger 314 to the inlet 336 of the pump 312. The pump 312 may then deliver the cooled output flow of coolant to the air compressor 300.
The self-contained cooling system 200 may also include one or more sensors. The one or more sensors may be one or more temperature sensors 340, 342, for example, or a combination of one or more different types of sensors. As an example, a first temperature sensor 340 may be provided adjacent to the coolant inlet 320 of the air compressor 300, e.g., on fluid delivery line 318. A second temperature sensor 342 may be provided adjacent to the coolant outlet 322, e.g., on fluid delivery line 334. The temperature sensors 340, 342 are used to measure or read the temperature of the coolant. In an embodiment, at least one temperature sensor 340 and/or 342 is located in the air compressor 300.
As shown in
The location and use of the illustrated temperature sensors 340, 342 as shown in
In accordance with an embodiment, a rate of flow of coolant (e.g., as pumped by pump 312) is based on the temperature of the coolant measured by the one or more of the temperature sensors 340, 342. In accordance with an embodiment, a speed of the fan 316 (e.g., as provided by a motor) is based on the temperature of the coolant measured by the one or more of the temperature sensors 340, 342 and/or a third temperature sensor. The temperature sensors 340, 342 and/or a third temperature sensor may be utilized to determine if the temperature of the circulating or flowing fluid and/or fan speed is adequate, or if adjustments to the flow rate of the coolant, and/or to the fan speed, for example, need to be made to any of the devices or parts of the system (e.g., the fan 316 and/or pump 312 and/or control valve 334) to provide the desired cooling to the air compressor 300.
As previously noted, the controller 310 controls the operation of at least the cooling system 200 disclosed herein. The controller 310 may control the operation of the air compressor 300 as well as the operation of the parts (e.g., pump 312, heat exchanger 314) used for cooling the air compressor 300.
In an embodiment, the controller 310 may be configured to communicate with the air compressor 300, the pump 312, the heat exchanger 314, and the fan 316 in the cooling system 200. The controller 310 may monitor and/or communicate with sensors (e.g., temperature sensors 340, 342) and any valves or controls (e.g., control valve 334 provided in the system). In an embodiment, the temperature sensors 340, 342 are communicatively coupled to with the controller 310 to provide temperature data from the coolant inlet 320 and outlet 322 of the air compressor 300. The controller 310 may use such data to adjust the coolant temperature that is flowing through the fluid delivery lines 318, 324, 330. For example, in an embodiment, the controller 310 is configured to cycle the coolant circulation pump 312 ON and OFF or vary the rate of flow of the coolant based on coolant temperature (e.g., as measured by the one or more temperature sensors 340, 342 and/or third temperature sensor). In an embodiment, the controller 310 is configured to instruct the fan 316 to increase or decrease its speed based on the coolant temperature measured by at least one of the sensors 340, 342 and/or a third temperature sensor, and thus increase or decrease the flow of cooling air on the heat exchanger 314, to facilitate a change in the temperature of the coolant that is output from the heat exchanger 314. The controller 310 may turn the fan 316 ON or OFF. In an embodiment, the controller 310 is configured to adjust a rate of flow of coolant through a plurality of fluid delivery lines 318, 324, 330 based on the temperature of the coolant, e.g., via adjustment of the rate at which the pump 312 pumps the coolant, or via adjustment of valves, such as valve 334, to an open position or a closed position, and/or in a position therebetween, to open, limit, adjust, and/or close flow of the coolant in the one or more fluid delivery lines 318, 324, 330. The controller 310 may control the pump 312 using one or more control signals transmitted from the controller 310 to the pump 312.
The controller 310 may also be used to limit circulation or flow of coolant throughout the cooling system 200. For example, when cooling is not required, e.g., when the air compressor 300 is not in operation or is not producing heat, the coolant will not be circulated.
The controller may be further used, as shown schematically in
The type of coolant used with the air compressor cooling system may be any type or number of coolants and is not intended to be limiting. In an embodiment, the coolant is a fluid. In an embodiment, the coolant is water. In an embodiment, the coolant is a propylene glycol solution, also referred to as “glycol.”
Accordingly, when the air compressor 300 is in operation and receiving and then compressing air, the temperature of the air compressor 300 of the locomotive may be controlled. For example, during such operation, the method includes pumping coolant to the air compressor 300 using the pump 312 to deliver coolant to the air compressor 300, passing the flow of coolant through the at least one passage 307 of the air compressor 300, outputting coolant from the at least one passage 307 of the air compressor 300 to the heat exchanger 314, removing the heat from the coolant with the heat exchanger 314, and directing the coolant from the heat exchanger 314 to the pump 312 for pumping. A temperature of the coolant in the passage 307 is determined using at least one temperature sensor 340 and/or 342 located in the air compressor 300, and a rate of flow of the coolant through the pump 312, air compressor 300, and heat exchanger 314 is controlled based on the temperature of the coolant as detected by the at least one temperature sensor 340 and/or 342. For example, the rate of flow of the coolant may increase as the temperature of the coolant increases to better facilitate removal of the heat of the heat exchanger 314. In an embodiment, the temperature of the coolant is determined by computing, e.g., using the controller 310 or other type of processing device, the average of a first temperature reading generated by the first temperature sensor 340 and a second temperature reading generated by the second temperature sensor 342.
The disclosed cooling system 200 provides sufficient cost savings to the locomotive industry since rebuilding an air compressor is expensive (e.g., the cost to rebuild may be several thousands of dollars). Further, air compressors that are damaged (e.g., due to freeze damage) typically crack the cooling jacket in the cylinder liner, which further adds to any rebuild cost. Other unscheduled or unanticipated failures also add to replacement or rebuild costs.
By replacing existing air compressor cooling systems that typically utilize engine water coolant with the herein disclosed self-contained cooling system 200 (that is separate from the engine cooling system), efficiency and temperature control are improved, resulting in performance optimization of the air compressor 300.
In addition to cooling and/or substantially maintaining a temperature of liquid cooled air compressors, and substantially reducing and/or eliminating freeze damage to liquid cooled air compressors (and/or parts thereof) as noted above, the herein disclosed cooling system 200 also eliminates thermal energy added to an engine's cooling system (which is typically found in the prior art when using recirculated engine coolant to cool an air compressor). Accordingly, the temperature of the engine coolant may be reduced since compressor cooling is separately maintained.
Further, the life of the air compressor 300 itself may be extended. The presence of cooler temperatures in the cooling system 200 also reduces oil consumption and provides drier air and, when used with an air brake system, improves air brake reliability. Moreover, little, if any, evaporation occurs. Use of this cooling system with the air compressor also results in a compressor that is less susceptible to oil deposits and corrosion on air compressor parts.
As previously mentioned, the compressed air output from the air compressor 300 may be used with any number of systems associated with the locomotive, or the train itself.
Brake cylinder(s) 416 are provided on the locomotives and controlled via movement of the piston contained inside the cylinder(s) 416. The piston applies brake blocks 418 to the wheels 108. The piston inside each brake cylinder 416 moves in accordance with the change in air pressure in the cylinder 416. As the air pressure changes, the application or release of the brake blocks 418 is controlled by the actuation of the brake pistons.
In an embodiment, an auxiliary reservoir 404 may be connected to the brake pipe 412 on an opposite side of the brake cylinder 416. The auxiliary reservoir 404 may be used to ensure there is a source of air available to operate the brake. A triple valve or distributor 414 may also be provided to control the flow of air into and out of the auxiliary reservoir 404. For example, the triple valve or distributor 414 may be used to release the brake, to apply the brake, and/or to hold the brake at its current level of application.
Although
Further, the type of locomotive 102 that utilizes the self-contained cooling system 200 is not intended to be limiting. The location of the locomotive 102 utilizing the cooling system 200 in a train 100 is also not limiting. The cooling system 200 may be provided in the locomotive 102 that is in a leading configuration, trailing configuration, or among a series of locomotives. For example, as shown in
Again, the disclosed cooling system 200 should not be limited for use with the described air brake system 210. For example, output air from the air compressor 300 may be used with a horn, an air starter, sanders, windshield wipers, radar lens cleaning, and/or air operated magnet valves. Moreover, it should be understood that the disclosed cooling system 200 may be manufactured, distributed, and/or provided as a package designed for retrofitting to an existing air compressor on a locomotive (e.g., attaching or configuring to a previously manufactured air compressor), or as a self-contained system comprising a combination of the air compressor and the cooling system in a single housing. The cooling system 200 may also be used in new locomotives, and it may be installed and/or used to replace existing systems.
Moreover, although the cooling system 200 has been described for use throughout this disclosure with a locomotive, it should be understood to one of ordinary skill in the art that the cooling system 200 as disclosed herein may be used in other types of vehicles, and thus its application is not limited for use with a locomotive.
While the principles of the disclosure have been made clear in the illustrative embodiments set forth above, it will be apparent to those skilled in the art that various modifications may be made to the structure, arrangement, proportion, elements, materials, and components used in the practice of the disclosure.
It will thus be seen that the features of this disclosure have been fully and effectively accomplished. It will be realized, however, that the foregoing preferred embodiments have been shown and described for the purpose of illustrating the functional and structural principles of this disclosure and are subject to change without departure from such principles. Therefore, this disclosure includes all modifications encompassed within the spirit and scope of the following claims.
