The present disclosure relates generally to a retarding and filter cleaning method and system and, more particularly, to a work machine having a gas turbine engine and employing a retarding and filter cleaning method and system.
Work machines such as, for example, on-highway and off-road haulage vehicles, wheeled tractors, track type tractors, and various construction work machines, may receive motive power from any one of a number of different types of engines. For example, a work machine may be powered by a gasoline engine, a diesel engine, or a gas turbine engine. Work machines powered by a gas turbine engine may use the gas turbine engine to drive a mechanism that may be used to transfer the engine power output into work machine propulsion or other work machine operations.
Work machines may require various retarders to aid braking. When descending slopes, for example, work machines may use retarding systems in order to dissipate kinetic energy so as to maintain a safe speed. For example, heavy work machines may use the momentum of the machine when moving down a slope to drive the engine. The engine, in the case of a piston engine such as, for example, a diesel engine, then operates as a compressor, dissipates kinetic energy, and retards the motion of the work machine.
Work machines may operate in environments characterized by dirt particles, dust, mud, rock particles, and other substances that may be detrimental to engine operation. The nature of a gas turbine engine dictates that it uses a large quantity of air. For example, a gas turbine engine may require as much as four time the air flow of a diesel engine comparable in power. Suitable filtering structure may be provided for precluding contaminants from reaching and damaging the engine. For example, in a work machine powered by a gas turbine engine, the intake air flow for the engine may be provided with one or more filters to ensure that the rather large flow of air directed to the gas turbine engine is reasonably free from contaminants that may harm the engine components.
Because of the rather large flow of air required by a gas turbine engine, and because the engine may operate in dusty, dirty conditions, air filters for gas turbine engines may require frequent cleaning or replacement. Frequent cleaning or replacement may require frequent down-time periods for the gas turbine engine and for the work machine.
It would be useful to provide a system, structure, and method whereby air filters for a gas turbine engine may be efficiently and effectively cleaned. Additionally, it would be useful if provision could be made for cleaning air filters for a gas turbine engine with only limited compromising of space constraints. Moreover, it would be particularly helpful if cleaning of the air filters could be accomplished effectively as a by-product of another work machine operation, such as work machine retarding, without experiencing work machine down time.
One method of cleaning an air filter for a gas turbine engine is described in U.S. Pat. No. 5,401,285 (the '285 patent) issued to Gillingham, et al. on Mar. 28, 1995. The '285 patent describes an air filter system that may be used in the gas turbine engine powered M1 tank. The '285 patent provides a pulse jet arrangement to direct air backward through the filter to regenerate it periodically between times of filter replacement. A compressed air tank is provided as a supply of compressed air for the pulse jets. The compressed air tank is supplied with compressed air by a bleed conduit from the turbine.
Although the method described in the '285 patent may recognize the need for frequent cleaning of air filters for a gas turbine engine, the '285 patent employs a separate system to do so. Rather than using an existing operation to directly facilitate filter cleaning, the '285 patent requires a system of compressed air tanks and “pulse jets,” as well as the space necessary for these components. Moreover, there is no recognition in the '285 patent that filter cleaning may be accomplished in association with a retarding function.
The disclosed retarding and filter cleaning method is directed to overcoming one or more of the problems outlined above with respect to existing technology.
In one aspect, the present disclosure includes a filter cleaning system for a gas turbine engine. The gas turbine engine includes a compressor section and a combustor section. A mechanism is operatively connected to the gas turbine engine and is configured to be driven by the gas turbine engine in a first mode and configured to drive the gas turbine engine in a second mode. A first flow path is provided for delivering air to the compressor section. At least one air filter is in the first flow path for filtering the air to be delivered to the compressor section. A second flow path is provided for delivering compressed air from the compressor section to the combustor section during the first mode. A third flow path is provided for delivering compressed air from the compressor section to the at least one air filter during the second mode.
In another aspect, the present disclosure includes a method of cleaning a filter for a gas turbine engine. In a first mode, a gas turbine engine including a compressor section and a combustor section drives a mechanism. Air is passed through at least one air filter and delivered to the compressor section. During the first mode, compressed air from the compressor section is delivered to the combustor section. During a second mode, the compressor section is driven by the mechanism. During the second mode, compressed air from the compressor section is delivered to clean the at least one air filter.
It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the claims.
Work machine 10 may include an air flow system generally indicated at 20. Air flow system 20 may include various conduits and valves, the arrangement and purpose of which will be explained in due course. Air flow system 20 may also include one or more air filters 22, 24 configured to substantially reduce the amount of dust, dirt particles, rocks, and various other contaminants drawn into gas turbine engine 12. It will be understood that the work machine may include only a single air filter, or it may include a plurality of air filters. To illustrate the disclosed system and method with reasonable simplicity, two filters are shown in
Gas turbine engine 12 may include a recuperator 26 configured to heat compressed air received from compressor section 14. The recuperator 26 may derive heat from turbine section 18 exhaust as the exhaust passes through the recuperator 26 on its way to the atmosphere. Combustor section 16 may be configured to receive heated, compressed air from the recuperator 26. The combustor section 16 may be provided with fuel from, for example, a fuel injection device schematically shown at 28. Ignition and burning of the heated, compressed air and fuel creates an exhaust gas with high energy. Turbine section 18 of gas turbine engine 12 is configured to convert energy from the exhaust gas into mechanical energy when the exhaust gas passes through turbine section 18. Turbine section 18 is operably coupled to a power shaft 30 configured to be rotated by turbine section 18.
Work machine 10 may further include a mechanism 32 operably coupled to power shaft 30. A drive connection, such as shaft 36 between compressor section 14 and mechanism 32, for example, may couple power shaft 30 to mechanism 32. Mechanism 32 is diagrammatically shown in
Mechanism 32 may be, for example, the lower power train of a work machine, including gearing mechanically coupled to wheels (not shown) and/or ground engaging tracks (not shown). Mechanism 32 may alternatively be a generator configured to convert mechanical energy developed by gas turbine engine 12 into electric energy for use as a power source to power, for example, one or more electric motors, such as electric motor 34, shown in
The various conduits and valves of air intake system 20 are illustrated in
A conduit 38 may enable the flow of air between air filter 22 and compressor section 14 while a conduit 40 may extend between air filter 24 and a suitable connection to conduit 38 to enable the flow of air from air filter 24 to compressor section 14. Valve 42 may be positioned in conduit 38 between air filter 22 and the location where conduit 40 connects to conduit 38. Valve 44 may be positioned in conduit 40. Valves 42 and 44 may be selectively controlled to permit the flow of air from a respective air filter 22, 24 in a first position of the valve, or to preclude the flow of air from a respective air filter 22, 24 in a second position of the valve.
A conduit 46 may enable the flow of compressed air from compressor section 14 into recuperator 26. Valve 48 may be mounted in conduit 46. Conduit 50 may extend between valve 48 and air filter 22 and enable flow of air from compressor section 14 to air filter 22. Conduit 52 may extend from conduit 50 to air filter 24 and enable flow of compressed air from compressor section 14 to air filter 24. Valve 54 may be situated in conduit 50 at a location between valve 48 and air filter 22. Conduit 52 may connect to conduit 50 at a location between valve 54 and valve 48. Valve 56 may be situated in conduit 52.
Valve 48 may be selectively controlled to permit the flow of compressed air along conduit 46 to recuperator 26, while precluding the flow of compressed air into conduit 50 or conduit 52. Valve 48 may also be selectively controlled to permit the flow of compressed air into conduit 50 while precluding the flow of compressed air into recuperator 26. Valves 54 and 56 may be selectively controlled to permit the flow of compressed air from compressor section 14 to a respective air filter 22, 24 in a first position of the valve, or to preclude the flow of compressed air from compressor section 14 to a respective air filter 22, 24 in a second position of the valve.
Air flow system 20 may be characterized as embodying different flow paths. For example, conduits 38 and 40, leading from air filters 22, 24 to compressor section 14 may be characterized as a first flow path 58 for delivering filtered air to compressor section 14. Conduit 46 may be characterized as a second flow path 60 for delivering compressed air from compressor section 14 to combustor 14.
It will be apparent that second flow path 60 is at least partly coextensive with third flow path 62. It will also be apparent that first flow path 58 includes two branches, one of which, in the exemplary embodiment, is conduit 40 leading from air filter 24, and the other of which is the portion of conduit 38 leading from air filter 22 up to the location where conduit 40 connects to conduit 38. Further, it will be apparent that third flow path 62 includes two branches, one of which, in the exemplary embodiment, is conduit 52 leading to air filter 24, and the other of which is the portion of conduit 50 leading from the location where conduit 52 connects to conduit 50 up to air filter 22.
In the exemplary work machine 10 schematically depicted in
Once compressed in compressor section 14, compressed air enters recuperator 26, where the compressed air may be heated by hot gases exhausted from turbine section 18. Following heating, the compressed air may be fed into combustor section 16, which may receive fuel from fuel injection device 28. Combustor section 16 ignites the compressed air and fuel, thereby creating a heated, high energy exhaust gas.
The heated exhaust gas may be passed through turbine section 18, which converts energy in the heated exhaust gas into mechanical energy as the heated exhaust gases pass through turbine section 18. Once it passes through turbine section 18, the exhaust gas may be fed into recuperator 26 to heat compressed air entering recuperator 26 from compressor section 14. The exhaust gases may thereafter be exhausted to the atmosphere.
Turbine section 18 may be operably coupled to power shaft 30, for example, via direct connection, such that when turbine section 18 rotates in response to the flow of the heated exhaust gas, power shaft 30 is also rotated. Power shaft 30 is operably coupled to compressor section 14 so that compressor section 14 may continue to compress air drawn in through, for example, air filter 22 and/or air filter 24. In addition to being operably coupled to compressor section 14, power shaft 30 may be operably coupled to mechanism 32 through, for example, shaft 36.
Mechanism 32 converts the energy output of gas turbine engine 12 into propulsion for work machine 10. In the embodiment of
Work machine 10 may be provided with a retarding system to supplement a braking system. For example, during downhill motion of the work machine, energy from the work machine is directed back through mechanism 32 to drive the gas turbine engine. For example, referring to
The second mode of operation is illustrated in
Filtered air may be supplied to compressor section 14 and compressed air may be delivered to at least one of the filters to clean the filter during the second, retarding mode. In order to permit both flow of filtered air to compressor section 14 and flow of compressed air to at least one of the air filters 22, 24, valves 42, 44, 54, and 56 may be coordinated in operation.
It can readily be seen that the disclosed embodiments provide for the more frequent cleaning of air filters that may be necessary with the use of a gas turbine engine, particularly during operation in an environment that produces substantial dust, dirt, and other contaminants that may be harmful to the engine. Instead of an entirely separate system for cleaning the filters, such as filters 22, 24, advantage is taken of an engine and work machine retarding function. Where the engine is not used to drive the mechanism 32 and provide power to the work machine, the work machine may be permitted to dissipate energy through driving mechanism 32. Where mechanism 32 is a generator, “motoring” the generator may drive the compressor section 14 of gas turbine engine 12 and simultaneously clean one or more of air filters 22, 24 with the compressed air output from compressor section 14.
For purposes of illustration, a particular arrangement of conduits and valves has been shown and described to diagrammatically depict the system and method disclosed. However, it will be understood by those skilled in the art that various arrangements of conduits and valves may be employed to create flow paths for delivering filtered air to the compressor section, for delivering compressed air to the combustor section, and for delivering compressed air to clean the air filters. The disclosure is not to be limited by the particular embodiments diagrammatically illustrated and described herein.
It will be apparent to those skilled in the art that various modifications and variations can be made to the disclosed turbine retarding and filter cleaning method and system. For example, while the system has been disclosed primarily in connection with retarding the motion of a work machine, it will be apparent that the method and system could be employed in a stationary system wherein a gas turbine engine drives a generator which in turn provides electric power. In such a situation, suitable circuitry could be provided by those skilled in the art for periodically driving the generator to drive the compressor section and enable filter cleaning. Other embodiments will be apparent to those skilled in the art from consideration of the specification and practice of the disclosed method and system. It is intended that the specification and examples be considered as exemplary only, with a true scope being indicated by the following claims and their equivalents.