TRANSMISSION SYSTEM FOR SELECTIVELY TRANSMITTING POWER FROM A TURBINE ENGINE - Patent application

Abstract

A system for providing efficient operation of a turbine engine is provided. A transmission (30) operably connected to an aircraft turbine engine (20) for selectively transferring power from a first pressure spool (75) of the turbine engine (20) to a second pressure spool (85) of the turbine engine to power an accessory (60). The transmission is configured to selectively operate in one of a first configuration and a second configuration. The first configuration transfers power from the turbine engine to the accessory, and the second configuration transfers power from the first high-pressure spool to the second high-pressure spool.

Description

[Technical Field]

[0001]

[0001] The present disclosure relates generally to the field of turbine engines, and more particularly to transmission systems for selectively transmitting power from turbine engines. [Background technology]

[0002]

[0002] Various aircraft are powered by turbine engines. These engines include a fan that provides a significant portion of the thrust for the overall propulsion system. The engine core generates additional thrust by driving the fan and directing the exhaust aft. In addition to providing thrust to propel the aircraft, the turbine engine also provides power to aircraft systems in the form of shaft power and pneumatic bleed air.

[0003]

[0003] When an aircraft is on the ground with the engine running at idle, the turbine engine provides shaft power for the aircraft's operation. Shaft power is typically extracted from the engine's core shaft (also called the N2 or high spool). Extracting shaft power from the high spool during ground operation increases ground idle fuel flow and reduces the stability margin of the high-pressure compressor.

[0004]

[0004] The turbine engine may also be configured to provide pneumatic bleed air to aircraft systems, including one or more components such as, but not limited to, an environmental control system for pressurizing the aircraft's passenger cabin and a thermal anti-icing system for providing heated air for anti-icing applications. The supply of air to the aircraft systems is typically provided by bleed air drawn from the turbine engine's high-pressure compressor.

[0005] Alternatively, the aircraft's pneumatic bleed air may be provided by an auxiliary compressor using shaft power and air from a lower stage of the engine compressor, the auxiliary compressor operating to provide air to the aircraft systems at the required pressure levels.

[0006]

[0006] What is needed is a system for providing efficient operation of a turbine engine. Summary of the Invention

[0007] One aspect is directed to a transmission operatively connected to an aircraft turbine engine for selectively transferring power from a first pressure spool of the turbine engine to a second pressure spool of the turbine engine to power an accessory. The transmission includes a gearbox, a power transfer clutch, an accessory clutch, and a gear set. The transmission is configured to selectively operate in one of a first configuration and a second configuration, where the first configuration transfers power from the turbine engine to the accessory. Where the second configuration transfers power from the first pressure spool to the second pressure spool.

[0008]

[0008] In another aspect, the transmission is configured to operate in a third configuration that prevents the transmission of power from the turbine engine to the accessory and prevents the transmission of power from the first pressure spool to the second pressure spool.

[0009]

[0009] In another aspect, a first configuration includes an accessory clutch engaged to transfer power from the turbine engine to an accessory, a second configuration includes a power transfer clutch engaged to transfer power from the first pressure spool to the second pressure spool, and a third configuration does not include engagement of either the accessory clutch or the power transfer clutch.

[0010]

[0010] In another aspect, a first configuration prevents the transmission of power from the first pressure spool to the second pressure spool, and a second configuration prevents the transmission of power from the turbine engine to an accessory.

[0011] In another aspect, a transmission is configured to transfer power from a second pressure spool to a first pressure spool.

[0012] In another aspect, in the first configuration, the transmission is powered by the second pressure spool.

[0013] In another aspect, the power transfer clutch and the accessory clutch are contained within a single housing configured to receive power from the first pressure spool and the second pressure spool.

[0014]

[0014] In another aspect, a piston extends within the housing, an accessory clutch plate is connected to the piston, a power transfer clutch plate is connected to the piston, the accessory clutch plate is engaged in a first configuration, the power transfer clutch plate is engaged in a second configuration, and neither the accessory clutch plate nor the power transfer clutch plate is engaged in a third configuration.

[0015] In another aspect, a one-way differential gear set prevents power sharing between the first pressure spool and the second pressure spool in the first configuration.

[0016]

[0016] In another aspect, the power transfer clutch includes a one-way clutch mechanism.

[0017]

[0017] In another aspect, a controller having processing circuitry is configured to operate the transmission in a first configuration for driving an accessory, in a second configuration for transferring power generated from the first pressure spool to the second pressure spool, and in a third configuration for preventing transfer of power from the turbine engine to the accessory and from the first pressure spool to the second pressure spool.

[0018] One aspect is directed to a transmission operatively connected to an aircraft turbine engine for selectively transferring power from a first pressure spool of the turbine engine to a second pressure spool of the turbine engine to provide power to an accessory to supply air to an aircraft system. The transmission includes a gearbox operatively connected to and powered by the second pressure spool, a power transfer clutch operatively connected to the first pressure spool, and an accessory clutch operatively connected to the gearbox, wherein the power transfer clutch and the accessory clutch are configured in a first configuration to transfer power from the second pressure spool to the accessory to power the accessory, and the power transfer clutch and the accessory clutch are configured in a second configuration to transfer power from the first pressure spool to the second pressure spool.

[0019]

[0019] In another aspect, a gear set is operably connected to each of the second pressure spool and the first pressure spool, and the gear set is configured to transmit power from the first pressure spool to the second pressure spool in the second configuration.

[0020]

[0020] In another aspect, the transmission, the power transfer clutch, and the accessory clutch are each separate components.

[0021]

[0021] In another aspect, a controller having a processing circuit is configured to operate the transmission in a first configuration to drive an accessory and in a second configuration to transmit power generated from a first pressure spool to a second pressure spool.

[0022] One aspect is directed to a method for use with an aircraft engine, the method including placing a transmission in a first configuration to transfer power from the turbine engine through a transmission and an accessory clutch to an accessory for supplying air from the turbine engine to an aircraft system, and placing the transmission in a second configuration to transfer power from a first pressure spool of the turbine engine through a power transfer clutch and the transmission to a second pressure spool of the turbine engine.

[0023] In another aspect, the method further includes preventing power from being transferred from the turbine engine to the accessory in the second configuration.

[0024] In another aspect, the method further includes transmitting power from a second pressure spool of the turbine engine to an accessory in the first configuration.

[0025] In another aspect, the accessory is a compressor, and the method further includes providing air to the aircraft system via a bleed air system when the transmission is in the first configuration.

[0026]

[0026] In another aspect, the method further includes, in a first configuration, engaging the accessory clutch and disengaging the power transfer clutch to transfer power from the turbine engine to the accessory, and, in a second configuration, engaging the power transfer clutch and disengaging the accessory clutch to transfer power from a first pressure spool of the turbine engine to a second pressure spool of the turbine engine.

[0027]

[0027] The above-described features, functions, and advantages can be realized alone in various aspects or can be combined in further multiple aspects, details of which can be confirmed by referring to the following description and accompanying drawings. [Brief explanation of the drawings]

[0028] [Figure 1]

[0028] FIG. 1 is an isometric view of an aircraft. [Figure 2]

[0029] 1 is a schematic diagram of a transmission for selectively transferring power between an engine and a compressor. [Figure 3]

[0030] 1 is a schematic diagram of a turbine engine and transmission transferring power between the engine and a compressor of a bleed air system. [Figure 4]

[0031] FIG. 1 is a schematic diagram of a transmission. [Figure 5]

[0032] FIG. 5 is a schematic diagram of the transmission of FIG. 4 in a configuration for providing power to a compressor. [Figure 6]

[0033] 5 is a schematic diagram of the transmission of FIG. 4 in a configuration for transmitting power in a turbine engine. [Figure 7]

[0034] 5 is a schematic diagram of the transmission of FIG. 4 in a configuration that does not provide power to a compressor or transmit power within a turbine engine. [Figure 8A]

[0035] FIG. 1 is a schematic diagram of a transmission configured to power a compressor. [Figure 8B]

[0036] FIG. 8B is a schematic diagram of the transmission of FIG. 8A in a configuration for transmitting power in a turbine engine. [Figure 9A]

[0037] FIG. 1 is a schematic diagram of a transmission configured to power a compressor. [Figure 9B]

[0038] FIG. 9B is a schematic diagram of the transmission of FIG. 9A in a configuration for transmitting power in a turbine engine. [Figure 10A]

[0039] FIG. 1 is a schematic diagram of a transmission configured to power a compressor. [Figure 10B]

[0040] FIG. 10B is a schematic diagram of the transmission of FIG. 10A in a configuration for transmitting power in a turbine engine. [Figure 11A]

[0041] FIG. 1 is a schematic diagram of a transmission configured to power a compressor. [Figure 11B]

[0042] FIG. 11B is a schematic diagram of the transmission of FIG. 11A in a configuration for transmitting power in a turbine engine. [Figure 12A]

[0043] FIG. 1 is a schematic diagram of a transmission configured to power a compressor. [Figure 12B]

[0044] FIG. 12B is a schematic diagram of the transmission of FIG. 12A in a configuration for transmitting power in a turbine engine. [Figure 13A]

[0045] FIG. 1 is a schematic diagram of a transmission configured to power a compressor. [Figure 13B]

[0046] FIG. 13B is a schematic diagram of the transmission of FIG. 13A in a configuration for transmitting power in a turbine engine. [Figure 14]

[0047] FIG. 2 is a schematic diagram of a controller. [Figure 15]

[0048] FIG. 1 is a schematic diagram of a controller configured to operate components to provide air to an aircraft system and to transmit power within a turbine engine. [Figure 16]

[0049] 1 is a flowchart of a method of operating a transmission. [Figure 17]

[0050] FIG. 1 is a schematic diagram of a transmission. DETAILED DESCRIPTION OF THE INVENTION

[0029]

[0051] 1 illustrates one embodiment of an aircraft 100. The aircraft 100 generally includes a fuselage 103 and wings 101. One or more turbine engines 20 are mounted to the wings 101 to propel the aircraft 100. A cockpit 102 is located forward of the fuselage 103 and includes controls for operating the aircraft 100. The aft section of the fuselage 103 includes a cabin area configured to accommodate passengers or cargo.

[0030]

[0052] The aircraft 100 includes aircraft systems 110. The aircraft systems 110 include one or more systems for operating various components, including, but not limited to, an environmental control system, a wing anti-icing system, an engine anti-icing system, and various other components that utilize heated and / or pressurized air. One or more of the turbine engines 20 provide bleed air to the aircraft systems 110 for use by one or more of the components, such as in the environmental control system. The bleed air may be provided during various operating conditions, such as, but not limited to, ground operation (taxiing), takeoff or climb, cruise, holding, and descent.

[0031]

[0053] The engines 20 provide thrust to propel the aircraft and power the aircraft's hydraulic and pneumatic systems. The engines 20 also provide shaft power to the aircraft electrical systems, including aircraft systems 110, aircraft computers, motor-driven hydraulic pumps, and / or other motors and electrical devices and accessories.

[0032]

[0054] Increased demand for aircraft accessory power increases the need to operate turbine engine 20 at higher idle speeds. More specifically, increasing engine idle speed allows the increased power demand to be met without sacrificing compressor stall margin. However, increased idle speed may also produce higher than desired thrust levels for turbine engine 20 during both flight idle descent and / or ground idle operations. Over time, continued operation at increased thrust levels during such idle operations may increase aircraft brake maintenance costs, and the increased fuel flow may directly increase aircraft operating costs.

[0033]

[0055] The present application is directed to a system 15 that transfers power from turbine engines 20 for efficient operation of an aircraft 100. In some embodiments, the engines 20 are configured to generate power to power accessories 60. In some embodiments, a first of the engines 20 operates to propel the aircraft 100, generate power, and provide bleed air. In some embodiments, two or more of the turbine engines 20 operate to generate power and provide bleed air, and thus include the same components and operate in the same manner. The following disclosure includes the operation of a single turbine engine 20. It is understood that two or more of the engines 20 may operate in substantially the same manner to provide power transfer to meet the demands of the aircraft 100.

[0034]

[0056] Power from one or more of the turbine engines 20 is mechanically transmitted to efficiently operate the aircraft 100 in various embodiments. As shown schematically in FIG. 2 , the transmission 30 is configured to selectively transmit power from the turbine engines 20. The transmission 30 is configured to transmit power to accessories 60. The transmission 30 is also configured to transmit power within the turbine engines 20. In one embodiment, the transmission 30 includes a gearbox 33, a power transfer clutch 34, and an accessory clutch 35.

[0035]

[0057] System 15 solves two problems associated with conventional aircraft. The first problem is providing power to accessories. In one particular embodiment where the accessory is a compressor, the first problem solved is that the bleed air supply is often inefficient due to the turbine engine providing air at a higher pressure than required by the aircraft systems. The second problem solved is that the engine operability is higher than desired idle levels, especially at ground idle.

[0036]

[0058] The architecture is configured to provide power to a variety of different devices, such as various airframe accessories and various engine accessories. One example includes a compressor that is driven to provide air to the aircraft 100. Other examples of accessories 60 include, but are not limited to, generators, hydraulic pumps, fuel pumps, and oil pumps.

[0037]

[0059] Some of the following examples include an accessory 60 that is a compressor. However, a compressor is just one example of a variety of devices that may be powered via the present configurations disclosed in this application.

[0038]

[0060] 3 shows a schematic diagram of a turbine engine 20 and its architecture for transmitting power and a compressor 60 configured to supply air to an aircraft system 110. The turbine engine 20 includes a fan 21 that draws air into a fan duct or compressor intake section and into a compressor 22. The compressor 22 includes one or more compressor sections. In some embodiments, such as shown in FIG. 2, the compressor 22 is a twin-shaft compressor 22 that includes a low-pressure compressor 70 and a high-pressure compressor 80. In some embodiments, the low-pressure compressor 70 and the high-pressure compressor 80 include various compressor stages that progressively increase the pressure of the air as it flows from the input section of the fan 21 to the combustor 25.

[0039]

[0061] Low-pressure compressor 70 is operatively coupled to a low-pressure shaft 71, and high-pressure compressor 80 is operatively coupled to a high-pressure shaft 81. Low-pressure shaft 71 is further coupled to a low-pressure turbine 72, and high-pressure shaft 81 is coupled to a high-pressure turbine 82. In some embodiments, such as shown in Figure 3, shafts 71, 81 are collinearly aligned, with the first shaft 71 disposed within the second shaft 81.

[0040]

[0062] In this embodiment, compressor 22 is a twin-shaft compressor including two compressor sections 70, 80. However, in other embodiments, compressor 22 may include more compressor sections, each having, for example, a turbine and a respective shaft.

[0041]

[0063] After exiting the high-pressure compressor 80, the highly compressed air is provided to the combustor 25, where fuel is injected, mixed with the highly compressed air, and ignited. The high-energy airflow exiting the combustor 25 rotates the blades of the turbines 72, 82, which are coupled to respective ones of the shafts 71, 81. The rotation of the shafts 71, 81 rotates the blades of the compressors 70, 80. The heated air is exhausted through the nozzle 26, where it mixes with cooler air provided by the fan 21, which bypasses the engine core, to generate forward thrust.

[0042]

[0064] Low pressure components including low pressure compressor 70, low pressure shaft 71, and low pressure turbine 72 form low pressure spool 75. High pressure components including high pressure compressor 80, high pressure shaft 81, and high pressure turbine 82 form high pressure spool 85.

[0043]

[0065] The bleed air system 40 supplies engine bleed air for use by the aircraft system 110 under various operating conditions. The bleed air system 40 includes one or more ports that draw air from the turbine engine 20. In some embodiments, such as shown in FIG. 3 , the bleed air system 40 includes a first bleed port 41 and a second bleed port 42. The second bleed port 42 is located downstream from the first bleed port 41, such that the pressure of the bleed air provided by the second bleed port 42 is higher than the pressure of the bleed air provided by the first bleed port 41. A passage 43 leads from the ports 41, 42 and may include one or more valves 45 for controlling the flow of air. The valves 45 include various configurations, including, but not limited to, one-way valves, check valves, pressure regulating valves, and shut-off valves. The initial passage 43 leads to a larger passage 46. In some embodiments, the bleed air provided by the first and second ports 41, 42 is elevated in temperature. The bleed air flows through a precooler 48 to reduce its temperature. The air is output into a passageway 47 and directed to the aircraft systems 110.

[0044]

[0066] Another passage 44 leads from the engine 20 to a compressor 60. In some embodiments, the compressor 60 is a shaft-driven compressor (SDC). The compressor 60 has a high horsepower capacity (e.g., 250 HP, 400 HP) and can be operated at a specific rotational speed to stay within its operating map. The compressor 60 compresses bleed air received through the passage and supplies the compressed air to the aircraft systems 110 through a passage 49. In some embodiments, the compressor 60 receives bleed air through the passage 44, increases the bleed air to a higher pressure, and outputs the air through the passage 49 to meet the demands of the aircraft systems 110. One or more valves 45 can be positioned along the passage 49 to control the flow of bleed air.

[0045]

[0067] The transmission 30 transmits power from the turbine engine 20 to operate the compressor 60. The transmission 30 adjusts or controls the gear ratio to drive the compressor 60 at a desired rotational speed or to provide a desired torque or power transmission. The high-pressure drive 31 and the low-pressure drive 32 transmit power from a high-pressure spool 85 of the turbine engine to the transmission 30. The drive mechanisms 31, 32 may include various configurations, such as, but not limited to, shafts, gear trains, and pulleys. In some embodiments, a gearbox (not shown) is connected to the drive mechanisms 31, 32 and the transmission 30. The gearbox includes a drive train with multiple gears to set the speed of the components. The transmission 30, the high-pressure drive 31, and the low-pressure drive 32 mechanically link the low-pressure spool 75 to the high-pressure spool 85. The drive mechanisms 31, 32 may be coupled to the spools 75, 85 in various manners. In some embodiments, the coupling is via a gear train (eg, comprising bevel gears) extending between the ends of the drive mechanisms 31, 32 and the respective spools 75, 85.

[0046]

[0068] In addition to powering the compressor 60, the transmission 30 is also configured to transmit mechanical power within the turbine engine 20. Mechanical power from the excess power available at the low-pressure spool 75 is directed back to the high-pressure spool 85, allowing the required speed of the high-pressure spool 85 to be maintained, but with reduced fuel flow. Furthermore, withdrawing power from the low-pressure spool 75 reduces the rotational speed of the low-pressure spool 75, which in turn reduces the rotational speed of the fan 21. Thus, unnecessary fan thrust is reduced, and the engine 20 can utilize the excess power to operate additional accessories in the aircraft system 110 without increasing fuel flow. As a result, the thrust and fuel flow of the turbine engine 20 are beneficially reduced at idle.

[0047]

[0069] The transfer of power from the low pressure spool 75 to the high pressure spool 85 occurs when the turbine engine 20 is producing excess thrust. The excess thrust is extracted from the low pressure spool 75 to power the high pressure spool 85.

[0048]

[0070] In some embodiments, such as shown in FIG. 4 , the transmission 30 includes a gearbox 33, a power transfer clutch 34, an accessory clutch 35, and a power transfer gear set 36. The power transfer clutch 34 and the compressor clutch 35 can include various configurations. Examples include, but are not limited to, a friction clutch, a one-way clutch (e.g., a sprag clutch), a positive-dog coupling (e.g., a curvilinear or splined coupling), a fluid coupling, and a torque converter. The gear set 36 transfers power between the drive mechanisms 31, 32 connected to the low-pressure spool 75 and the high-pressure spool 85, respectively. In some embodiments, the transmission 30 includes a continuously variable transmission. In other embodiments, the transmission 30 includes different configurations, such as, but not limited to, a constant speed transmission, a variable speed transmission with a torque converter, and an electric-based motor / generator continuously variable transmission.

[0049]

[0071] Transmission 30 operates in one of three configurations: the first configuration provides power to accessory 60; the second configuration transmits power between spools 75, 85; and the third configuration neither powers accessory 60 nor transmits power between spools 75, 85.

[0050]

[0072] 5 illustrates one embodiment in which the transmission 30 is in a first configuration for powering the compressor 60. In this configuration, the power transfer clutch 34 is disengaged and the compressor clutch 35 is engaged. Power from the high-pressure spool 85 is transferred through the transmission 33 and the engaged compressor clutch 35 to power the compressor 60 and provide air to the aircraft system 110. In some embodiments, the first configuration occurs when the bleed air system 40 is not supplying air to the aircraft system 110.

[0051]

[0073] 6 illustrates one embodiment of a second configuration for transferring power between spools 75, 85. The power transfer clutch 34 is engaged and the compressor clutch 35 is disengaged. Power from the low-pressure spool 75 is transferred to the high-pressure spool 85. In this configuration, the bleed air system 40 supplies air to the aircraft system 110 when the compressor 60 is not powered through the transmission 30. In some embodiments, this power transfer configuration occurs during steady-state operation of the turbine engine 20, such as during ground idle. Additionally or alternatively, this configuration is used during transient operation of the turbine engine 20, such as during rapid acceleration in flight.

[0052]

[0074] 7 illustrates one embodiment of the third configuration. The transmission 30 includes the power transfer clutch 34 and the compressor clutch 35 that are both disengaged, so that no power is transferred to the compressor 60 or between the spools 75, 85. In some embodiments, this configuration occurs when the bleed air system 40 is providing air to the aircraft system 110. In one embodiment, this occurs when the bleed air system 40 is supplying air close to the critical requirements of the aircraft system 110.

[0053]

[0075] In some embodiments, such as those shown in FIGS. 8A and 8B, the power transfer clutch 34 is a sprag clutch or includes another one-way clutch mechanism. Sprag clutches are lighter and less complicated than friction clutches. In some embodiments using a sprag clutch, a larger operating ratio is required for the transmission 33 when the transmission 30 is configured to power the compressor 60 to prevent the sprag clutch from overrunning. A larger operating ratio also provides for the sprag clutch to remain engaged when the transmission 30 is configured to transfer power between spools 75, 85. FIG. 8A shows the compressor clutch 35 engaged and the transmission 30 powering the compressor 60. The high operating ratio of the transmission 33 prevents the sprag clutch from overrunning. FIG. 8B shows the transmission 30 configured to transfer power between spools 75, 85 and the sprag clutch 34 engaged at a low operating ratio of the transmission 33 to provide for the sprag clutch 34 to remain engaged. A bleed air system 40 provides air to the aircraft systems 110 .

[0054]

[0076] In some embodiments, the sprag clutch 34 includes a sprag clutch 178, a sprag clutch input shaft, and a sprag clutch output shaft. The sprag clutch 34 may also include speed sensors, such as speed pickups attached to the input and output shafts and / or encoders attached directly to the shafts. The speed sensor measurements are output to a controller 120 that monitors the operation of the transmission 30.

[0055]

[0077] In some embodiments, such as those disclosed above (e.g., FIG. 8 ), the high-pressure spool 85 drives the transmission 33 and the low-pressure spool 75 drives the power transfer clutch 34. In some embodiments, this configuration is reversed. In some embodiments, reversing these inputs optimizes the operating speed band of the spools 75, 85, narrowing the speed range of the transmission 33 required to prevent the sprag clutch of the power transfer clutch 34 from overrunning while the compressor 60 is operating. FIG. 9A shows the transmission 30 configured with the compressor clutch 35 engaged so that the transmission 30 provides power from the low-pressure spool 75 to the compressor 60. In this configuration, the compressor 60 provides air to the aircraft system 110, and the transmission 33 has a high operating ratio to prevent the sprag clutch 34 from overrunning. In some embodiments, no air is provided by the bleed air system 40.

[0056]

[0078] 9B shows the power transfer configuration of transmission 30 with power transfer clutch 34 (which in this example is a sprag clutch) engaged to transfer power between spools 75, 85. In some examples, gearbox 33 has a low operating ratio to keep the sprag clutch engaged. In some examples, in this configuration, bleed air system 40 provides air to aircraft system 110.

[0057]

[0079] In some embodiments disclosed above, the drive mechanisms 31, 32 that transfer power from the spools 75, 85 to the transmission 30 are separate and spaced apart. In other embodiments, the drive mechanisms 31, 32 are combined into a single unit. This improves packaging, eliminates parts, and reduces the size envelope. Figures 10A and 10B show an embodiment in which the drive mechanisms 31, 32 are concentric. In this embodiment, the drive mechanism 32 is located inside the drive mechanism 31. Other embodiments may include the reverse configuration.

[0058]

[0080] As shown, the power transfer clutch 34 and the compressor clutch 35 are mounted together within a single housing 55. The power transfer clutch 34 and the compressor clutch 35 are further mounted on concentric shafts to reduce the volume of the transmission 30. In one embodiment, the power transfer clutch 34 is a sprag clutch, although other types of mechanisms may be used. Figure 10A shows a configuration in which the compressor clutch 35 is engaged to power the compressor 60 and provide air to the aircraft 110 systems. In some embodiments, in this configuration, the bleed air system 40 does not provide air.

[0059]

[0081] Figure 10B shows the power transfer configuration with power transfer clutch 34 engaged and compressor clutch 35 disengaged, thereby transferring power from low pressure spool 75 to high pressure spool 85. In some embodiments where power transfer clutch 34 is a sprag clutch, transmission 33 has a high operating ratio to prevent overrun when powering compressor 60 (Figure 10A) and a low operating ratio during power transfer (Figure 9B) to keep the sprag clutch engaged.

[0060]

[0082] In some embodiments, such as those shown in FIGS. 11A and 11B, the transmission 30 includes a dual output friction clutch 37. The dual output friction clutch 37 integrates the functions of the power transfer clutch 34 and the compressor clutch 35 into a single component. The dual output friction clutch 37 reduces weight and envelope size relative to a two-component approach (including a separate power transfer clutch 34 and compressor clutch 35). The dual acting friction clutch 37 includes a hydraulic piston 38 configured to engage clutch plates 39a and 39b. FIG. 11A illustrates a configuration for powering the compressor 60, with the piston 38 engaged with clutch plate 39b, which functions to provide power to the compressor 60. FIG. 11B illustrates a configuration for transferring power from spool 75 to spool 85. The piston 38 engages clutch plate 39a. The dual output friction clutch 37 thereby provides power transfer without powering the compressor 60.

[0061]

[0083] In some embodiments, such as those shown in FIGS. 12A and 12B, the transmission 30 includes an open differential gear set 50. The open differential gear set 50 is located between the drive mechanisms 31 and 32. This transmission 30 does not include a power transfer clutch 34. FIG. 12A illustrates a first operating configuration providing power to the compressor 60. In this configuration, the compressor clutch 35 is disengaged, and the spools 75 and 85 drive the compressor 60 via the drive mechanisms 31 and 32. In some embodiments, the differential input speed of the spools 75 and 85 equals the drive speed of the compressor 60 (i.e., speed of 32 + speed of 31 = compressor speed). FIG. 12B illustrates the transmission 30 in a power transfer mode. Additionally, the compressor clutch 35 is engaged to lock the compressor 60. Additionally, the gear set 50 couples the drive mechanisms 31 and 32. In this configuration, the compressor clutch 35 serves as a braking clutch, which allows for simplification, weight reduction, and size reduction.

[0062]

[0084] 13A and 13B show an embodiment in which transmission 30 includes one-way differential gearset 51 and power transfer clutch 34, which in this embodiment is a sprag clutch. During configuration to power compressor 60, one-way differential gearset 51 and the sprag clutch on spool 75 prevent sharing of drive power between spools 75, 85. This is achieved when compressor 60 is braked by coupling spools 75, 85 together via one-way differential gearset 51 and the sprag clutch. This arrangement provides a narrower speed range compared to an open differential design.

[0063]

[0085] Figure 13A shows transmission 30 in a first configuration powering compressor 60. In this configuration, compressor 60 is driven only by spool 85 because the sprag clutch is overrun. Figure 13B shows a power transfer configuration with compressor clutch 35 engaged to lock compressor 60. In this configuration, locking compressor 60 creates a different transmission ratio through the differential, thereby engaging sprag clutch 34 and providing power transfer between spools 75, 85.

[0064]

[0086] A controller 120 controls operation of the transmission 30. The controller 120 executes instructions to engage one or more of the components of the transmission 30 (e.g., the gearbox 33, the power transfer clutch 34, the compressor clutch 35) to selectively provide operation and power transfer of the compressor 60. The controller 120 operates based on several factors, including one or any combination of the following: the ground speed of the aircraft 100, the weight on the wheels of the aircraft 100 (e.g., indicating that the aircraft 100 is landing), or during different stages of the operation of the aircraft 100. Exemplary stages of the operation of the aircraft 100 that may trigger operation of the transmission 30 include ground idle operation of the aircraft 100, when the aircraft 100 is taxiing, when the aircraft 100 is entering takeoff mode, during descent of the aircraft 100, or during flight of the aircraft 100 to support the restart of another turbine engine 20. In some embodiments, controller 120 receives signals from one or more other systems (e.g., flight controllers) on aircraft 100 to identify the contributing factors.

[0065]

[0087] FIG. 14 illustrates a controller 120 that operates the transmission 30. The controller 120 is a computing device that includes a processing circuit 121. The processing circuit 121 controls the operation of the transmission 30 according to program instructions 129 stored in a memory circuit 122. The processing circuit 121 includes one or more circuits, a microcontroller, a microprocessor, hardware, or a combination thereof. The memory circuit 122 includes a non-transitory computer-readable storage medium that stores the program instructions 129. The non-transitory computer-readable storage medium configures the processing circuit 121 to perform one or more of the techniques described herein. The memory circuit 122 may include various memory devices, such as, for example, read-only memory and flash memory. The memory circuit 122 may be a separate component as shown in FIG. 12 or may be combined with the processing circuit 121.

[0066]

[0088] Communications circuitry 123 provides communication with one or more of the components, including, but not limited to, transmission 30, compressor 60, turbine engine 20, and bleed air system 40. Communications circuitry 123 is configured for communication over one or more wired and / or wireless communication links. In some embodiments, communications circuitry 123 is configured for communication with one or more remote nodes located remotely from aircraft 100.

[0067]

[0089] User interface 124 is provided for a person, such as a pilot or flight crew member, to monitor and / or control one or more aspects of transmission 30. In some embodiments, user interface 124 is located in the cockpit for use during flight. User interface 124 includes one or more input devices 125, such as, but not limited to, a keypad, touchpad, rollerball, and joystick, that provide for commands to be input into processing circuit 121. User interface 124 may also include one or more displays 126 for displaying information.

[0068]

[0090] In some embodiments, a single dedicated controller 120 monitors and / or controls operation of the transmission 30 to control power transmission and / or air supply. In other embodiments, operation occurs via two or more controllers 120. FIG. 15 illustrates a system having various levels of controllers 120, including an accessory 60 that is a compressor that may supply air to the aircraft system 110. The controllers 120 include a first level controller 120 that includes an engine controller 120a and an air supply controller 120b. The second level controller 120 includes a loop controller 120c and a valve controller 120d. In some embodiments, higher level controllers function to control general aspects of air control and power transmission. Lower level controllers function to control more specific aspects. In the embodiment of FIG. 13, the loop controller 120c controls the transmission 33, the power transfer clutch 34, and the compressor clutch 35. The valve controller 120d controls the valve 45 and the compressor 60.

[0069]

[0091] In some embodiments, operation of the transmission 30 to power the compressor 60 includes an air supply controller 120b commanding a desired speed ratio for the transmission 33. The air supply controller 120b also controls the valve 45 and the compressor 60. In the power transmission configuration, the engine controller 120a controls the transmission 33 to command the desired speed ratio.

[0070]

[0092] 16 illustrates a method of operating the transmission 30. The method includes placing the transmission 30 in a first configuration (block 200). The first configuration transfers power from the turbine engine 20 to the accessory 60. The method also includes placing the transmission 30 in a second configuration (block 202). The second configuration transfers power from the first pressure spool 75 to the second pressure spool 85 of the turbine engine 20.

[0071]

[0093] In one particular embodiment where the accessory 60 is a compressor, the method includes placing the transmission 30 in a first configuration for transferring power from the turbine engine 20 to the compressor 60 to supply air from the turbine engine 20 to the aircraft system 110. The method also includes placing the transmission 30 in a second configuration for transferring power from a low-pressure spool 75 to a high-pressure spool 85 of the turbine engine 20.

[0072]

[0094] In some embodiments, when the transmission 30 is configured to transfer power between the low pressure spool 75 and the high pressure spool 85, the compressor 60 cannot be used when power is being transferred between the spools 75, 85. In some embodiments, the reason for this is that the transmission ratio is not suitable for operating the compressor 60 when power is being transferred between the spools 75, 85. However, the ability to transfer power between the spools 75, 85 is generally realized during ground idle, and the two functions of power transfer and the compressor 60 do not interfere with each other.

[0073]

[0095] In some embodiments, when the compressor 60 is powered, the air bleed system 40 does not provide air to the aircraft systems 110. In other embodiments, the air bleed system 40 and the compressor 60 both simultaneously supply air to the aircraft systems 110. In some embodiments, the bleed air system 40 supplies air to the aircraft systems without the compressor 60, such as during ground idle.

[0074]

[0096] In some embodiments, a gearbox including a drive train with multiple gears is operatively connected to the drive mechanisms 31, 32 to set the speed.

[0075]

[0097] 17 shows a transmission 30 including a gearbox 33, a power transfer clutch 34, and a gear set 36. In this transmission 30, there is no accessory clutch 35. When in power transfer mode, the accessory 60 continues to rotate and consumes some power. An accessory surge bleed valve is open in power transfer mode, reducing the power demand of the accessory 60.

[0076]

[0098] In some embodiments, such as those shown schematically, the transmission 30 is integrated into a single unit. In some specific embodiments, the transmission 30 is contained within a housing. In other embodiments, one or more of the components of the transmission are separate. For example, the gearbox 33 is mounted separately from the power transfer clutch 34 and the accessory clutch 35. The separate components may be mounted in various locations within the turbine engine 20 and / or other sections of the aircraft 100. One or more of the components may be integrated into other existing components. For example, the power transfer clutch 34 is located in the drive mechanism 32.

[0077]

[0099] In some embodiments, system 15 advantageously allows for reduced fuel consumption and engine thrust at idle by transferring horsepower from low-pressure spool 75 to high-pressure spool 85. To the extent that taxiing operations may require thrust above idle levels, system 15 may remain engaged throughout the entire taxiing operation to prevent repeated clutch operation and to provide power transfer at thrust levels above idle for taxiing operations. Examples show that use of system 15 can result in significant idle fuel flow reduction.

[0078]

[0100] System 15 also beneficially allows for precise control of the speed of high-pressure spool 85 (e.g., to meet electrical frequency requirements during uninterrupted power transfer). Use of system 15 may likewise be selectively controlled, for example, disengaging clutch 34 in climb and cruise conditions where there is little or no benefit to power transfer to potentially avoid friction on clutch 34 and / or the power transfer unit and avoid power loss from operating the system. Selective control may further be provided via manual pilot control of system 15, and an indication as to the status of power transfer may be provided in cockpit 102.

[0079]

[0101] In some embodiments, the system 15 may be used during flight idle (eg, during descent) to reduce thrust or fuel flow.

[0080]

[0102] Furthermore, although this description generally describes power transfer as occurring via power generated by the low-pressure spool 75 being transferred to the high-pressure spool 85, power transfer can occur in the other direction. For example, power generated from the high-pressure spool 85 is transferred to the low-pressure spool 75. Thus, the system 15 is bidirectional and can operate to transfer power in either direction. For example, there are situations where it may be advantageous to transfer power from the high-pressure spool 85 to the low-pressure spool 75. One instance occurs when the speed of the high-pressure spool 85 needs to be adjusted, such as when performing uninterrupted power transfer with a variable frequency generator attached to the high-pressure gearbox. Another application occurs during cruise, where power is transferred from the high-pressure spool 85 to the low-pressure spool 75 as trim in the thermodynamic cycle of the turbine engine 20 to improve fuel consumption. Yet another application may occur to transfer power from the high-pressure spool 85 to the low-pressure spool 75 as a way to reduce the sizing point for the low-pressure turbine 72. Because the high-pressure turbine 82 rotates at a higher RPM than the low-pressure turbine 72, the specific size and weight of the high-pressure turbine 82 is smaller as a function of power. Therefore, during engine operating conditions where the low-pressure turbine 72 might have been oversized, it may be advantageous to use a power transfer to transfer power from the high-pressure spool 85 to the low-pressure spool 75.

[0081]

[0103] The term "substantially" in connection with a quantity or measurement means that the recited characteristic, parameter, or value need not be achieved exactly. Rather, deviations or variations (including, for example, tolerances, measurement errors, measurement accuracy limits, and other factors known to those skilled in the art) may occur to the extent that they do not eliminate the effect intended to be produced by the feature.

[0082]

[0104] In some embodiments, engine 20 includes two spools 75, 85 (e.g., a high spool and a low spool). In other embodiments, engine 20 includes one or more intermediate pressure spools that provide for power transfer from a lower pressure spool to a higher pressure spool (e.g., from an intermediate spool to a high pressure spool, or from a low pressure spool to an intermediate spool).

[0083]

[0105] Aspects disclosed herein apply to many different engine architectures, including, but not limited to, open rotor engines, turboshaft engines, geared turbofan engines, and three-spool engines.

[0084]

[0106] The present disclosure may be practiced otherwise than as specifically set forth herein without departing from the essential characteristics of the invention. The present embodiments are to be considered in all respects as illustrative and not restrictive, and all changes that come within the meaning and range of equivalency of the claims are intended to be embraced within their scope. [Explanation of symbols]

[0085] 15 Systems 20. Turbine Engine 21 Fan 22 Compressor 25 Combustor 30 Transmission 31 Drive mechanism (HP) 32 Drive mechanism (LP) 33 Transmission 34 Power Transmission (PT) Clutch 35 Accessory clutch 36 Gear Set 37 Dual Output Friction Clutch 38 Piston 39 Clutch plate 40 Bleed Air System 41 First Port 42 Second Port 43 Passage 44 Passage 45 valves 46 Passage 47 Passage 48 Precooler Aisle 49 50 Open differential gear set 51 One-way differential gear set 55 Housing 60 Accessories 70 First Compressor (LP) 71 First Axis 72 Turbine (LP) 75 spool (LP) 80 Second Compressor (HP) 81 Second Axis 82 Turbine (HP) 85 spool (HP) 100 aircraft 101 Main wing 102 Cockpit 103 Torso 110 Aircraft Systems 120 Controller 121 Processing circuit 122 Memory Circuit 123 Communication Circuit 124 User Interface 125 input devices 126 Display 129 Programming Instructions

Claims

1. 1. A transmission (30) operatively connected to a turbine engine (20) of an aircraft (100) for selectively transferring power from a first pressure spool (75) of the turbine engine (20) to a second pressure spool (85) of the turbine engine (20) to power an accessory (60), comprising: Transmission (33), power transmission clutch (34), an accessory clutch (35), and a gear set (36); the transmission is configured to selectively operate in one of a first configuration and a second configuration; the first arrangement transmits power from the turbine engine to the accessory; The second arrangement transmits power from the first pressure spool (75) to the second pressure spool (85).

2. 10. The transmission of claim 1, further comprising the transmission configured to operate in a third configuration that prevents the transfer of power from the turbine engine to the accessory and prevents the transfer of power from the first pressure spool to the second pressure spool.

3. the first arrangement comprising the accessory clutch (35) engaged to transfer power from the turbine engine (20) to the accessory (60); the second arrangement comprising the power transfer clutch (34) engaged to transfer power from the first pressure spool (75) to the second pressure spool (85); 3. The transmission of claim 2, wherein the third configuration does not include engagement of either the accessory clutch (35) or the power transfer clutch (34).

4. the first configuration prevents the transmission of the power from the first pressure spool (75) to the second pressure spool (85); The transmission of claim 1 , wherein the second configuration prevents the transfer of the power from the turbine engine (20) to the accessory (60).

5. The transmission of claim 1, further comprising the transmission (30) configured to transfer power from the second pressure spool (85) to the first pressure spool (75).

6. 2. The transmission of claim 1, wherein in said first configuration, said variator (33) is powered by said second pressure spool (85).

7. 2. The transmission of claim 1, wherein the power transfer clutch (34) and the accessory clutch (35) are contained within a single housing configured to receive the power from the first pressure spool (75) and the second pressure spool (85).

8. a piston (38) extending into the housing; an accessory clutch plate (39) connected to the piston (38); and a power transmission clutch plate (39) connected to the piston (38); the accessory clutch plate (39) is engaged in the first configuration; the power transfer clutch plates (39) are engaged in the second configuration; 8. The transmission of claim 7, wherein neither the accessory clutch plates nor the power transfer clutch plates are engaged in the third configuration.

9. 2. The transmission of claim 1, further comprising a one-way differential gear set (51) that prevents power sharing between the first pressure spool (75) and the second pressure spool (85) in the first configuration.

10. 2. The transmission of claim 1, wherein the power transfer clutch (34) comprises a one-way clutch mechanism.

11. 3. The transmission of claim 2, further comprising a controller having a processing circuit configured to operate the transmission in the first configuration to drive the accessory, in the second configuration to transfer the power generated from the first pressure spool to the second pressure spool, and in the third configuration to prevent the transfer of power from the turbine engine to the accessory and from the first pressure spool to the second pressure spool.

12. 1. A transmission (30) operatively connected to a turbine engine (20) of an aircraft (100) for selectively transferring power from a first pressure spool (75) of the turbine engine (20) to a second pressure spool (85) of the turbine engine (20) to power an accessory (60), comprising: a transmission (33) operatively connected to and powered by said second pressure spool (85); a power transfer clutch (34) operatively connected to the first pressure spool (75); and an accessory clutch (35) operably connected to the transmission (33); the power transfer clutch (34) and the accessory clutch (35) are configured in a first configuration to transfer power from the second pressure spool (85) to the accessory (60) to power the accessory (60); the power transfer clutch (34) and the accessory clutch (35) are configured in a second configuration to transfer power from the first pressure spool (75) to the second pressure spool (85).

13. 13. The transmission of claim 12, further comprising a gear set (36) operatively connected to each of the second pressure spool (85) and the first pressure spool (75), the gear set (36) configured to transfer the power from the first pressure spool (75) to the second pressure spool (85) in the second configuration.

14. 13. The transmission of claim 12, wherein each of the speed changer (33), the power transfer clutch (34), and the accessory clutch (35) are separate components.

15. 13. The transmission of claim 12, further comprising a controller (120) having a processing circuit (121), the controller (120) configured to operate the transmission (30) in the first configuration to drive the accessory (60) and in the second configuration to transfer the power generated from the first pressure spool (75) to the second pressure spool (85).

16. A method for use with a turbine engine (20) of an aircraft (100), comprising: placing the transmission (30) in a first configuration to transmit power from the turbine engine (20) through a gearbox (33) and an accessory clutch (35) to an accessory (60); and placing the transmission (30) in a second configuration and transmitting power from a first pressure spool (75) of the turbine engine (20) through a power transfer clutch (34) and the gearbox (33) to a second pressure spool (85) of the turbine engine (20).

17. The method of claim 16, further comprising preventing power from being transmitted from the turbine engine (20) to the accessory (60) in the second configuration.

18. The method of claim 16, further comprising transmitting the power from the second pressure spool (85) of the turbine engine (20) to the accessory (60) in the first configuration.

19. 17. The method of claim 16, wherein the accessory is a compressor, and the method further includes providing air to an aircraft system via a bleed air system when the transmission is in the first configuration.

20. in the first configuration, engaging the accessory clutch (35) and disengaging the power transfer clutch (34) to transfer the power from the turbine engine (20) to the accessory (60); and 17. The method of claim 16, further comprising engaging the power transfer clutch and disengaging the accessory clutch in the second configuration to transfer the power from the first pressure spool of the turbine engine to the second pressure spool of the turbine engine.

Images