Aircraft hybrid power source system and control method thereof

Abstract

This aircraft hybrid motive power source system is installed in an aircraft and comprises: a gas turbine engine (20) that includes a low-pressure shaft (27) and a high-pressure shaft (28) as rotating shafts; a first electric generator (31) that is drivably connected to the high-pressure shaft (28); a second electric generator (32) that is drivably connected to the low-pressure shaft (27); a fuel cell (40) to which fuel gas and oxidant gas are supplied; a fuel gas generation unit (50) that generates fuel gas from a raw material through heating using exhaust gas of the gas turbine engine (20); and a control unit (60) that, on the basis of information indicating the running state of the gas turbine engine (20) and / or demand for electric power in the aircraft, supplies, to the first electric generator (31) or the second electric generator 32, electric power of the fuel cell (40) obtained through the supply of fuel gas.

Description

Technical Field

[0001] The present disclosure relates to an aircraft hybrid power source system that combines a gas turbine engine and a fuel cell as power sources for thrust.

Background Art

[0002] Conventional gas turbine engines mounted on aircraft not only generate thrust for the aircraft but also generate electric power consumed by the aircraft by driving a generator.

[0003] In recent years, with the demand from aircraft electrification (MEA: More Electric Aircraft) and the like, the in-aircraft power demand has been increasing. Therefore, not only a power generation method that utilizes the extraction power from the high-pressure shaft, which has been common until now, but also a power generation method that utilizes the extraction power from the low-pressure shaft has been proposed (see Patent Document 1).

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] There are situations where the thrust required for the propulsion fan is relatively low, such as during taxiing and landing. Under such circumstances, it is necessary to reduce the rotational speed of the gas turbine engine. However, generally, gas turbine engines have the characteristic that their thermal efficiency decreases in the low rotational speed range. Therefore, under the above-mentioned circumstances, the thermal efficiency is likely to decrease and the fuel consumption deteriorates. Moreover, since the rotational speed decreases, the power generation amount also decreases.

[0006] The present disclosure has been made in view of the above circumstances, and an object thereof is to provide an aircraft hybrid power source system capable of improving fuel consumption and a control method therefor. [Means for solving the problem]

[0007] A first aspect of the present disclosure of an aircraft hybrid power source system includes a gas turbine engine mounted on an aircraft and including a low-pressure shaft and a high-pressure shaft as rotating shafts; a first motor-generator driven and connected to the high-pressure shaft; a second motor-generator driven and connected to the low-pressure shaft; a fuel cell supplied with fuel gas and oxidizer gas; a fuel gas generation unit that generates the fuel gas from raw materials by heating using the exhaust gas of the gas turbine engine; and a control unit that supplies power from the fuel cell obtained by supplying the fuel gas to one of the first motor-generator and the second motor-generator, based on at least one of information indicating the operating status of the gas turbine engine and the power demand of the aircraft.

[0008] The aircraft hybrid power source system according to the first embodiment may further include a heat exchanger that heats the exhaust from the fuel cell and cools the fuel gas by heat exchange between the fuel gas supplied to the fuel cell and the exhaust from the fuel cell, and a supercharger that compresses the oxidizer gas and supplies it to the fuel cell by supplying the exhaust from the fuel cell heated by the heat exchanger. The aircraft hybrid power source system according to the first embodiment may further include a heating device that preheats the raw materials supplied to the fuel gas generation unit.

[0009] A second aspect of the present disclosure of an aircraft hybrid power source system includes a gas turbine engine mounted on an aircraft and including a low-pressure shaft and a high-pressure shaft as rotating shafts; a first motor-generator driven to the high-pressure shaft; a second motor-generator driven to the low-pressure shaft; a fuel cell supplied with fuel gas and oxidizer gas; a heat exchanger that heats the exhaust gas of the fuel cell by heat exchange between the exhaust gas from the gas turbine engine and the exhaust gas of the fuel cell; a supercharger that compresses the oxidizer gas and supplies it to the fuel cell upon supply of the heated exhaust gas of the fuel cell; and a control unit that supplies power from the fuel cell obtained by supplying the fuel gas to one of the first motor-generator and the second motor-generator, based on at least one of information indicating the operating status of the gas turbine engine and the power demand of the aircraft.

[0010] In the first or second embodiment, the supercharger may be an electric supercharger equipped with a third motor-generator. In this case, the control unit supplies power to the electric supercharger obtained by supplying the emissions from the fuel cell to one of the first motor-generator and the second motor-generator, based on at least one of information indicating the operating status of the gas turbine engine and the amount of power demanded within the machine.

[0011] A control method for an aircraft hybrid power source system according to a third aspect of the present disclosure involves generating fuel gas for a fuel cell from raw materials by heating with exhaust gas from a gas turbine engine mounted on an aircraft, which includes a low-pressure shaft and a high-pressure shaft as rotating shafts; supplying the fuel gas to the fuel cell; and supplying the power of the fuel cell obtained by the supply of the fuel gas to one of a first motor-generator driven by the high-pressure shaft and a second motor-generator driven by the low-pressure shaft, based on at least one of information indicating the operating status of the gas turbine engine and the power demand of the aircraft.

[0012] The control method according to the third embodiment may heat the exhaust from the fuel cell with the heat of the fuel gas supplied to the fuel cell, and supply the heated exhaust from the fuel cell to the turbine of the turbocharger, thereby compressing and supplying the oxidizer gas of the fuel cell from the compressor of the turbocharger to the fuel cell. Furthermore, the control method according to the third embodiment may heat the raw materials before generating the fuel gas from them.

[0013] A control method for an aircraft hybrid power source system according to a fourth aspect of the present disclosure involves heating the exhaust gas from a gas turbine engine mounted on an aircraft, including a low-pressure shaft and a high-pressure shaft as rotating shafts, by heat exchange between the exhaust gas from the fuel cell and the exhaust gas from the fuel cell, thereby increasing the pressure of the fuel cell's exhaust gas, supplying the increased pressure of the fuel cell's exhaust gas to a turbocharger's turbine, supplying fuel gas discharged from the turbocharger's compressor to the fuel cell, and supplying the power of the fuel cell obtained by the supply of fuel gas to one of a first motor-generator driven by the high-pressure shaft and a second motor-generator driven by the low-pressure shaft, based on at least one of information indicating the operating status of the gas turbine engine and the aircraft's power demand.

[0014] In the third or fourth embodiment, the supercharger may be an electric supercharger equipped with a third motor-generator. In this case, the control method in each embodiment supplies the power of the electric supercharger obtained by supplying the exhaust from the fuel cell to one of the first motor-generator and the second motor-generator. [Effects of the Invention]

[0015] This disclosure provides an aircraft hybrid power source system and a control method thereof that can improve fuel efficiency. [Brief explanation of the drawing]

[0016] [Figure 1] Figure 1 is a block diagram showing the configuration of the hybrid system according to the first embodiment of this disclosure. [Figure 2]FIG. 2 is a perspective view showing the configuration of a unit cell of a fuel cell according to each embodiment of the present disclosure. [Figure 3] FIG. 3 is a perspective view showing a main part of a fuel gas generation section according to a first embodiment of the present disclosure. [Figure 4] FIG. 4 is a block diagram showing the configuration of a hybrid system according to a modification of the first embodiment of the present disclosure. [Figure 5] FIG. 5 is a diagram showing the operating status of each device in an example of an operating mode of a hybrid system according to each embodiment of the present disclosure. [Figure 6] FIG. 6 is a block diagram showing the configuration of a hybrid system according to a second embodiment of the present disclosure. MODE FOR CARRYING OUT THE INVENTION

[0017] Hereinafter, some embodiments of the present disclosure will be described. In the drawings, the same reference numerals are assigned to the common parts, and duplicate descriptions will be omitted. The aircraft hybrid power source system according to the present embodiment includes at least an aircraft gas turbine engine, a fuel cell, and a control unit. These are installed in an aircraft (not shown).

[0018] The aircraft hybrid power source system utilizes the exhaust heat of the gas turbine engine for power generation of the fuel cell, and supplies the power obtained thereby to each device of the aircraft according to the operating condition of the aircraft. The devices to which the power of the fuel cell is supplied also include a motor generator that is drivingly connected to the rotating shaft of the gas turbine engine. That is, the power of the fuel cell is used not only as power for avionics, air conditioning, etc., but also as power for assisting the gas turbine engine.

[0019] Hereinafter, for the sake of convenience of explanation, the aircraft hybrid power source system is simply referred to as the hybrid system, and the gas turbine engine is simply referred to as the engine. The engine according to this embodiment includes, for example, a turbofan engine, a turbojet engine, a turboprop engine, a turboshaft engine, and the like. Also, as will be described later, the engine includes a low-pressure shaft as a rotating shaft connecting the low-pressure compressor and the low-pressure turbine, and a high-pressure shaft as a rotating shaft connecting the high-pressure compressor and the high-pressure turbine. That is, the engine according to this embodiment is a multi-shaft gas turbine engine.

[0020] (First Embodiment) The first embodiment of the present disclosure will be described. The hybrid system 10A according to this embodiment generates fuel gas for a fuel cell by utilizing the heat of the exhaust gas from the engine. The fuel cell generates electric power by the supply of the fuel gas. Further, the hybrid system 10A utilizes the electric power obtained from the fuel cell as electric assist for the engine or power for electrical equipment according to the operating conditions of the aircraft. As a result, it is possible to improve the thermal efficiency of the gas turbine engine, improve fuel consumption, reduce carbon emissions, and the like.

[0021] FIG. 1 is a block diagram showing the configuration of the hybrid system 10A according to this embodiment. As shown in FIG. 1, the hybrid system 10A includes an engine 20, a first motor generator 31, a second motor generator 32, a fuel cell �0, a fuel gas generation unit 50, and a control unit 60. These are installed in an aircraft (not shown).

[0022] First, let's describe the engine. The basic configuration of the engine 20 according to this embodiment is the same as that of a conventional turbofan engine. That is, the engine 20 is a twin-shaft turbofan engine and includes a fan 21, a low-pressure compressor 22, a high-pressure compressor 23, a combustion chamber 24, a high-pressure turbine 25, and a low-pressure turbine 26. The low-pressure compressor 22, the low-pressure turbine 26, and the fan 21 are connected to each other via a low-pressure shaft (low-pressure spool) 27, which serves as a rotating shaft. The fan 21 may also be connected to the low-pressure shaft 27 via a gear (not shown). The high-pressure compressor 23 and the high-pressure turbine 25 are connected to each other via a high-pressure shaft (high-pressure spool) 28, which serves as a rotating shaft.

[0023] The basic operation of engine 20 (for example, compression of gas, combustion, conversion of pressure energy to kinetic (rotational) energy, etc.) is the same as that of a conventional engine. That is, fan 21 draws in gas as the working fluid from the front of fan 21 and discharges it from the rear of fan 21. A portion of the gas that has passed through fan 21 flows into low-pressure compressor 22. Low-pressure compressor 22 compresses the gas that has flowed in from fan 21 and discharges it to high-pressure compressor 23. High-pressure compressor 23 further compresses the gas that has been compressed by low-pressure compressor 22 and supplies it to combustion chamber 24.

[0024] The combustion chamber 24 burns a mixture of gas compressed by the high-pressure compressor 23 and fuel supplied from the fuel tank 35 via the fuel supply device 36. The amount of fuel supplied is set by the control unit 60, and the fuel supply device 36 supplies an amount of fuel to the combustion chamber 24 based on that set value. The combustion gas is discharged to the high-pressure turbine 25, and as it passes through the high-pressure turbine 25, it expands and rotates the high-pressure turbine 25. This rotational energy is transmitted to the high-pressure compressor 23 via the high-pressure shaft 28, causing the high-pressure compressor 23 to rotate.

[0025] The combustion gas that has passed through the high-pressure turbine 25 expands further as it passes through the low-pressure turbine 26, causing it to rotate. This rotational energy is transmitted to the low-pressure compressor 22 and fan 21 via the low-pressure shaft 27, causing the low-pressure compressor 22 and fan 21 to rotate. A portion of the combustion gas that has passed through the low-pressure turbine 26 is supplied to the fuel gas generation unit 50, which will be described later, and the remainder is released to the outside of the engine 20.

[0026] The first motor-generator (high-voltage shaft MG) 31 is driven and connected to the high-voltage shaft 28 via the first drivetrain 33. That is, when the first motor-generator 31 operates as a generator, a portion of the rotational energy of the high-voltage shaft 28 is transmitted to the first motor-generator 31 via the first drivetrain 33. Also, when the first motor-generator 31 operates as an electric motor, the rotational energy of the first motor-generator 31 is transmitted to the high-voltage shaft 28 via the first drivetrain 33.

[0027] The second motor-generator (low-voltage shaft MG) 32 is driven and connected to the low-voltage shaft 27 via the second drivetrain 34. That is, when the second motor-generator 32 operates as a generator, a portion of the rotational energy of the low-voltage shaft 27 is transmitted to the second motor-generator 32 via the second drivetrain 34. Also, when the second motor-generator 32 operates as an electric motor, the rotational energy of the second motor-generator 32 is transmitted to the low-voltage shaft 27 via the second drivetrain 34.

[0028] The first motor-generator 31 and the second motor-generator 32 are housed together with auxiliary equipment such as a fuel pump and a starter in a well-known accessory gearbox (AGB, not shown). However, their location is not limited to the AGB. For example, the second motor-generator 32 may be housed in a tail cone (not shown). In this case, the second motor-generator 32 is driven to the rear end of the low-voltage shaft 27.

[0029] In this embodiment, the engine 20 may also be a three-shaft gas turbine engine further comprising an intermediate-pressure compressor (not shown), an intermediate-pressure turbine (not shown), and an intermediate-pressure shaft (intermediate-pressure spool, not shown) as a rotating shaft connecting them. In this case, a motor-generator (not shown) may also be driven and connected to the intermediate-pressure shaft. The motor-generator driven and connected to the intermediate-pressure shaft also operates as an electric motor or generator based on at least one of information indicating the operating status of the engine 20 and the power demand of the aircraft.

[0030] Next, the fuel gas generation unit will be described. In this embodiment, the fuel gas generation unit 50 generates fuel gas for the fuel cell 40 from raw materials by heating using the exhaust gas of the engine 20. This raw material is, for example, ammonia. Ammonia has a higher hydrogen density per unit volume than hydrogen, making it suitable for storage in aircraft where space is limited.

[0031] The raw materials are stored in liquid form in the raw material tank 37 and supplied to the fuel gas generation unit 50 by the raw material supply device 38. The raw material supply device 38 is equipped with a pump such as a gear pump that can adjust the discharge rate. The amount of raw materials supplied by the raw material supply device 38 is set by the control unit 60. The raw material supply device 38 supplies the amount of raw materials to the fuel gas generation unit 50 based on the set value.

[0032] An example of the configuration of the fuel gas generation unit 50 will be described. Figure 2 is a perspective view showing an example of the main part of the fuel gas generation unit 50. The fuel gas generation unit 50 is a so-called reformer or catalytic reactor. As shown in Figure 2, the fuel gas generation unit 50 has, for example, a heat medium flow path 51 and a reaction flow path 52. The heat medium flow path 51 and the reaction flow path 52 are formed on one side and the other side of, for example, a plate member 53. The plate member 53 and the partition wall 54 are made of a material with high thermal conductivity such as metal, and they are stacked alternately. Therefore, the heat medium flow path 51 and the reaction flow path 52 are thermally coupled to each other via the plate member 53 or the partition wall 54.

[0033] The inlet (upstream side) of the heat transfer fluid channel 51 is connected to a duct (not shown) of the engine 20. The outlet (downstream side) of the heat transfer fluid channel 51 is connected to piping (not shown) that continues to the outside of the engine 20. On the other hand, the inlet (upstream side) of the reaction channel 52 is connected to the outlet of the raw material supply device 38. The outlet (downstream side) of the reaction channel 52 is connected to the primary side inlet of the heat exchanger 55.

[0034] A packing material (not shown) on which a catalyst is supported is provided within the reaction channel 52. Alternatively, the catalyst may be supported on the inner surface of the reaction channel 52. The catalyst contains components that promote the hydrogen production reaction at relatively high temperatures (e.g., 300°C to 900°C). When the raw material is ammonia, the catalyst may be nickel or ruthenium, or other metals or alloys.

[0035] The exhaust gas EG from the engine 20 is supplied to the heat transfer fluid passage 51. This supply of exhaust gas heats the fuel gas generation unit 50 to approximately 450°C or higher, which is the operating temperature of the catalyst. When ammonia gas AG, the raw material, is supplied to the reaction passage 52 in this state, a mixed gas of hydrogen and nitrogen is produced by a catalytic reaction. This mixed gas is used as the fuel gas for the fuel cell 40.

[0036] The temperature of the fuel gas immediately after it is generated by the fuel gas generation unit 50 is several hundred degrees Celsius, which is higher than the operating temperature of the fuel cell 40 assumed in this embodiment (for example, 70°C to 90°C). Therefore, in this embodiment, the fuel gas is cooled by the heat exchanger 55 before being supplied to the fuel cell 40.

[0037] As described above, the primary inlet of the heat exchanger 55 is connected to the outlet of the reaction channel 52 in the fuel gas generation unit 50. The primary outlet of the heat exchanger 55 is connected to the inlet of the first channel 46 in the fuel cell 40. The secondary inlet of the heat exchanger 55 is connected to the outlet of the second channel in the fuel cell. The secondary outlet of the heat exchanger 55 is connected to piping (not shown) that leads to the outside of the engine 20.

[0038] Fuel gas flows through the primary side of the heat exchanger 55. Meanwhile, steam, an exhaust from the fuel cell 40, flows through the secondary side of the heat exchanger 55. As a result, heat exchange occurs between the fuel gas and the steam, the fuel gas is cooled, while the steam is heated and released to the outside of the engine 20.

[0039] Furthermore, if a fuel cell with a relatively high operating temperature, in other words, an operating temperature close to the fuel gas temperature, is used, the heat exchanger 55 may be omitted.

[0040] Next, the fuel cell will be described. The fuel cell 40 in this embodiment is a polymer electrolyte fuel cell (PEFC). As is well known, a PEFC generates electricity through the reaction of hydrogen, a component of the fuel gas, and oxygen, a component of the oxidizing gas. The fuel cell in this embodiment is required to respond quickly (within a few seconds) to the set power value requested by the control unit 60. The PEFC is an example of a fuel cell that satisfies this output performance. Note that the fuel cell 40 may be a fuel cell other than a PEFC, as long as the above response performance can be obtained.

[0041] Figure 3 is a perspective view showing the configuration of a unit cell 41 of the fuel cell 40 according to this embodiment. As shown in this figure, the fuel cell 40 has a plurality of separators 42 and a plurality of unit cells 41. The separators 42 and unit cells 41 are stacked alternately.

[0042] The unit cell 41 includes an electrolyte membrane 43, an anode 45 as a fuel electrode, and a cathode 47 as an oxygen electrode (air electrode). The electrolyte membrane 43 is located between the anode 45 and the cathode 47. The electrolyte membrane 43 is a solid polymer membrane having cationic conductivity, for example, a hydrocarbon polymer electrolyte membrane.

[0043] The anode 45 and cathode 47 are electrodes formed from a porous material supporting a catalyst. The porous material is, for example, carbon, and the catalyst is, for example, platinum or a platinum-containing alloy.

[0044] Each separator 42 is a plate member arranged parallel to the unit cell 41 and serves as a wall separating adjacent unit cells 41. The separator 42 is made of metal, carbon, or conductive plastic. The separator 42 has a first flow path 46 through which fuel gas FG flows on the surface in contact with the anode 45. The separator 42 also has a second flow path 48 through which oxidizer gas OG flows on the surface in contact with the cathode 47.

[0045] The first channel 46 is composed of, for example, a plurality of grooves extending in a predetermined direction. The inlet (upstream side) of the first channel 46 is connected to the primary side outlet of the heat exchanger 55. The outlet (downstream side) of the first channel 46 is connected to piping (not shown) that continues outside the engine 20.

[0046] The second channel 48 is composed of, for example, multiple grooves extending in a predetermined direction. The inlet (upstream side) of the second channel 48 is connected to the outlet of an air supply device 56, such as a pump or blower. The outlet (downstream side) of the second channel 48 is connected to the secondary inlet of the heat exchanger 55. It also functions as a discharge channel for waste products (i.e., water) generated during the power generation of the fuel cell 40. In other words, waste products from the fuel cell 40 are supplied to the secondary side of the heat exchanger 55.

[0047] When hydrogen is supplied as fuel gas to the first channel 46 and air containing oxygen as oxidizing gas is supplied to the second channel 48, the fuel cell 40 generates electricity through a well-known chemical reaction. In addition, water, which is a reaction product, is discharged from the second channel 48 of the fuel cell 40. This water is supplied to the secondary side of the heat exchanger 55 and used to cool the fuel gas.

[0048] The fuel gas supplied from the fuel gas generation unit 50 contains nitrogen gas. However, nitrogen gas does not affect, or has a very small effect on, the series of chemical reactions in the fuel cell 40. Therefore, in this embodiment, the device for separating nitrogen gas from the fuel gas can be omitted.

[0049] The electricity generated by the fuel cell 40 is distributed via the power grid (power supply system) 61 to equipment that requires power in accordance with the aircraft's operating status. An example of such equipment is the first motor-generator (high-voltage shaft MG) 31 mentioned above. Further details will be described later.

[0050] Next, the control unit will be described. The control unit 60 in this embodiment is configured as a computer that works in conjunction with FADEC (full authority digital engine control). Based on at least one of the information indicating the operating status of the engine 20 (hereinafter referred to as operating status information) and the aircraft's power demand, the control unit 60 calculates the amount of power to be supplied to the aircraft equipment 62 and supplies the calculated amount of power to each aircraft equipment 62 via the power system 61.

[0051] Engine 20 operating status information includes measured values ​​from pressure sensors, temperature sensors, and flow sensors attached to the engine 20, as well as external temperature, altitude, the flow rate of jet fuel supplied to the engine 20, and the operating mode setting value according to the angle position (PLA) of the power lever. Aircraft power demand refers to the amount of electricity required for various aircraft equipment 62 such as avionics and air conditioning. The above information and power demand change constantly due to changes in the operating mode and changes in the external environment.

[0052] This aircraft equipment 62 also includes a first motor-generator 31 and a second motor-generator 32. In other words, the control unit 60 supplies power from the fuel cell 40 obtained by supplying fuel gas to one of the first motor-generator 31 and the second motor-generator 32, based on at least one of the operating status information of the engine 20 and the power demand of the aircraft, thereby assisting in their operation.

[0053] The power generated from the power generation equipment, including the first motor-generator 31, the second motor-generator 32, and the fuel cell 40, is transmitted to the power grid 61. The power grid 61 consists of various switches, relays, busbars, etc., and functions as equipment for supplying and distributing power. The power grid 61 is controlled by the control unit 60, which supplies the power obtained from each power generation device to aircraft equipment 62 such as avionics and air conditioning, or to the first motor-generator 31 or the second motor-generator 32 when operation as an electric motor is required.

[0054] A modified version of the first embodiment will now be described. Figure 4 is a block diagram of a hybrid system 10B according to a modified version of the first embodiment. As shown in this figure, the hybrid system 10B according to this modified version may include a supercharger 70. In this case, the air supplyer 56 that was connected to the second flow path 48 of the fuel cell 40 is omitted. From another perspective, it can be said that the air supplyer 56 operates as a compressor 72 for the supercharger 70.

[0055] The supercharger 70 comprises a turbine 71 and a compressor 72 that rotates integrally with the turbine 71. The inlet of the turbine 71 is connected to the secondary outlet of the heat exchanger 55. The outlet of the turbine 71 is connected to, for example, an exhaust pipe (not shown) that leads to the outside of the engine 20. The inlet of the compressor 72 is connected to, for example, an intake pipe (not shown) that leads to the outside of the engine 20. The outlet of the compressor 72 is connected to the inlet (upstream side) of the second flow path of the fuel cell 40.

[0056] As described above, the inlet of the turbine 71 is connected to the secondary outlet of the heat exchanger 55. Therefore, the waste product (i.e., water) from the fuel cell 40 that has passed through the heat exchanger 55 is pressurized into steam by heating in the heat exchanger 55 and flows into the turbine 71. This steam rotates the turbine 71, and the compressor 72 rotates along with this rotation.

[0057] The rotating compressor 72 draws in air as an oxidizing gas and compresses it. The compressed air is discharged from the compressor 72 and flows into the second flow path 48 of the fuel cell 40. In other words, the supercharger 70 compresses the oxidizing gas and supplies it to the fuel cell 40 by supplying the exhaust from the fuel cell 40, which has been heated by the heat exchanger 55. This promotes the generation of electricity by the fuel cell 40 and increases the amount of electricity obtained.

[0058] The supercharger 70 may also be an electric supercharger equipped with a third motor-generator 73. In this case, power can also be obtained from the third motor-generator 73 by the rotation of the turbine 71 due to the supply of steam, and the total amount of power obtained will increase. The control unit 60 may supply the power obtained from the third motor-generator 73 to one of the first motor-generator 31 and the second motor-generator 32 based on at least one of the operating status information of the engine 20 and the power demand of the aircraft.

[0059] Furthermore, the hybrid system 10A (10B) may further include a heating device 57. The heating device 57 has a well-known configuration including a combustor or electric heater and preheats the raw material supplied to the fuel gas generation unit 50. The raw material is heated to a temperature at which the catalytic reaction proceeds in the reaction channel 52 of the fuel gas generation unit 50 without receiving heat from the heat transfer medium channel 51. The raw material heated to this temperature is decomposed into fuel gas in the reaction channel 52 and supplied to the fuel cell 40.

[0060] Next, some examples of control by the hybrid system according to this embodiment will be described. Figure 5 is a diagram showing the operating status of each device in an example of the operating mode of the hybrid system according to this embodiment. In each operating mode, the power source and the main device that receives that power are indicated by arrows. Note that the high-voltage shaft MG refers to the first motor-generator 31, and the low-voltage shaft MG refers to the second motor-generator 32. "M" in the box means that the motor-generator is operating as an electric motor, and "G" in the box means that the motor-generator is operating as a generator. In this example, the supercharger 70 is an electric supercharger and is equipped with a third motor-generator.

[0061] In any operating mode, the control unit 60 continuously acquires information on the operating status of the engine 20 and the aircraft's power demand. The control unit 60 also pre-acquires the maximum amount of power that the second motor-generator 32 can generate. When the second motor-generator 32 is operating as a generator, the control unit 60 sets the amount of power generated by the second motor-generator 32 within this maximum power range, and also sets the amount of raw materials supplied by the raw material supply device 38 and the amount of oxidizer gas supplied by the air supply device 56 (or supercharger 70). In other words, the control unit 60 sets the distribution between the amount of power generated by the second motor-generator 32 and the amount of power generated by the fuel cell 40.

[0062] 1. Ground standby (idle) mode The aircraft is waiting at the airport and is stopped in its designated location. In this mode, combustion in the engine 20 is stopped. Consequently, the rotation of the low-pressure shaft 27 and high-pressure shaft 28 by combustion gases is also stopped. In this mode, all aircraft equipment 62 is powered by the fuel cell 40, and no jet fuel is consumed. Therefore, jet fuel consumption can be reduced, which means carbon emissions can be reduced.

[0063] For example, the raw material supply device 38 and the heating device 57 are operated, and high-temperature raw materials are supplied to the reaction channel 52 of the fuel gas generation unit 50. While the raw materials are flowing through the reaction channel 52, the reaction channel 52 is heated, and the temperature inside the reaction channel 52 reaches the operating temperature of the catalyst. As a result, the catalytic reaction proceeds, and fuel gas for the fuel cell 40 is generated from the raw materials. The generated fuel gas is cooled in a heat exchanger and supplied to the first channel 46 of the fuel cell 40.

[0064] Meanwhile, the turbocharger 70 also operates by receiving power from the fuel cell 40, compressing air, which is the oxidizer gas, and supplying it to the second flow path 48 of the fuel cell 40. Within the fuel cell 40, electricity is generated by the supply of fuel gas and oxidizer gas. The generated electricity is transmitted to the power grid 61 and, under control by the control unit 60, is supplied to equipment that requires power in this operating mode.

[0065] 2-1. First Taxiing Mode The aircraft is taxiing within the airport. To obtain the minimum necessary thrust, engine 20 starts burning jet fuel and rotates fan 21. However, since engine 20 is operating at a low rotation speed, its thermal efficiency is low. Therefore, power from fuel cell 40 is supplied to the first motor generator (high-pressure shaft MG) 31 to assist the rotation of the high-pressure shaft 28. This increases the compression ratio of the working fluid in the high-pressure compressor 23, improving thermal efficiency.

[0066] In this mode, a portion of the exhaust gas from the engine 20 flows into the heat transfer medium passage 51 of the fuel gas generation unit 50, and the heat transfer medium passage 51 and the reaction passage 52 are heated to a temperature above the operating temperature of the catalyst. A set amount of raw material is supplied to the heated reaction passage 52 from the raw material supply device, which is set by the control unit 60, thereby generating a desired amount of fuel gas.

[0067] Similar to the ground standby mode, the supercharger 70 is also operating in taxiing mode. Consequently, electricity is generated in the fuel cell 40, and a portion of the generated electricity is supplied to the first motor-generator (high-voltage shaft MG) 31. The remaining portion of the generated electricity is supplied to the aircraft equipment 62.

[0068] 2-2. Second Taxiing Mode The aircraft is taxiing within the airport. However, unlike the first taxiing mode described above, the engine 20 is not operating due to combustion. Instead, the heating device 57 and supercharger 70 are operating, generating electricity for the fuel cell 40. The electricity from the fuel cell 40 is supplied to the second motor-generator (low-pressure shaft MG) 32, which operates as an electric motor. This causes the low-pressure shaft 27 to rotate, and the fan 21 to rotate. In other words, thrust for taxiing is obtained. Since jet fuel is not consumed, jet fuel consumption can be reduced. In other words, fuel efficiency can be improved.

[0069] 3-1. First Takeoff Mode This is the state in which the thrust obtained by the engine 20 is maximized. In this mode, the fuel cell 40 supplies power to the first motor-generator 31, which assists the rotation of the high-pressure shaft 28. The assistance from the first motor-generator 31 lowers the temperature of the combustion gas at the inlet of the high-pressure turbine 25, thereby extending the life of the high-pressure turbine 25.

[0070] 3-2. Second Takeoff Mode Similar to the first takeoff mode, this is the state in which the thrust obtained by the engine 20 is maximized. However, unlike the first takeoff mode, the fuel cell 40 supplies power to the aircraft equipment 62, but not to the first motor generator 31.

[0071] 4. Cruising mode Engine 20 is operating at its highest thermal efficiency, allowing the second motor-generator 32 to be used as a generator. Since the power from the second motor-generator 32 can supply the aircraft's equipment 62, the fuel cell 40 and all devices that operate the fuel cell 40 are shut down.

[0072] 5. Descent Mode The output and thrust of engine 20 are reduced. Since engine 20 operates at low rotational speeds, its thermal efficiency deteriorates. In this mode, the fuel cell 40 is operated and its power is supplied to the first motor-generator 31. Furthermore, the second motor-generator is operated as a generator and its power is also supplied to the first motor-generator 31. This improves thermal efficiency and thus fuel efficiency.

[0073] (Second Embodiment) A second embodiment of this disclosure will now be described. Figure 6 is a block diagram showing the configuration of the hybrid system 10C in the second embodiment. The hybrid system 10C uses the heat from the exhaust gas of the engine 20 to heat the exhaust of the fuel cell 40. Therefore, as shown in Figure 6, the exhaust gas from the engine 20 is supplied to the primary side inlet of the heat exchanger 55. In addition, the fuel gas generation unit 50 of the first embodiment is omitted, and hydrogen gas as fuel gas is supplied directly to the first flow path 46 of the fuel cell 40. The other configurations are the same as those of the first embodiment and operate in the same manner as the first embodiment. Therefore, the same effects as the first embodiment can be obtained.

[0074] In each of the embodiments described above, a gas turbine engine and a fuel cell are used in combination as the power source for thrust. Engine assistance using electricity from the fuel cell is performed based on at least one of the following: information indicating the engine's operating status and the aircraft's power demand. Since the heat from exhaust gases from the engine 20, which was previously simply wasted, is used to generate electricity for this fuel cell, fuel efficiency can be improved. In addition, since carbon-free fuel is used as the fuel to obtain thrust or electricity, carbon emissions can be reduced.

[0075] This disclosure can contribute, for example, to Sustainable Development Goal (SDG) 7, "Ensure access to affordable, reliable, sustainable, and modern energy for all."

[0076] Furthermore, this disclosure is not limited to the embodiments described above, but includes all modifications within the meaning and scope of the claims as indicated by the claims.

Claims

1. A gas turbine engine, equipped on an aircraft, includes a low-pressure shaft and a high-pressure shaft as rotating shafts, A first motor-generator is driven and connected to the high-voltage shaft, A second motor-generator is connected to the low-voltage shaft for drive, A fuel cell supplied with fuel gas and oxidizer gas, A fuel gas generation unit that generates the fuel gas from raw materials by heating using the exhaust gas of the gas turbine engine, A control unit supplies power from the fuel cell, obtained by supplying fuel gas, to one of the first motor-generator and the second motor-generator, based on at least one of the information indicating the operating status of the gas turbine engine and the power demand of the aircraft. An aircraft hybrid power system equipped with [specific features / features].

2. A heat exchanger that heats the fuel gas from the fuel cell and cools the fuel gas by heat exchange between the fuel gas supplied to the fuel cell and the fuel gas from the fuel cell, A supercharger compresses the oxidizer gas and supplies it to the fuel cell by supplying the exhaust from the heated fuel cell. The aircraft hybrid power source system according to claim 1, further comprising:

3. The unit further comprises a heating device for preheating the raw materials supplied to the fuel gas generation unit. The aircraft hybrid power source system according to claim 1.

4. A gas turbine engine, equipped on an aircraft, includes a low-pressure shaft and a high-pressure shaft as rotating shafts, A first motor-generator is driven and connected to the high-voltage shaft, A second motor-generator is connected to the low-voltage shaft for drive, A fuel cell supplied with fuel gas and oxidizer gas, A heat exchanger that heats the exhaust gas from the fuel cell by heat exchange between the exhaust gas from the gas turbine engine and the exhaust gas from the fuel cell, A supercharger that compresses the oxidizing gas and supplies it to the fuel cell by supplying the exhaust from the fuel cell heated by the heat exchanger, A control unit supplies power from the fuel cell, obtained by supplying fuel gas, to one of the first motor-generator and the second motor-generator, based on at least one of the information indicating the operating status of the gas turbine engine and the power demand of the aircraft. An aircraft hybrid power system equipped with [specific features / features].

5. The supercharger is an electric supercharger equipped with a third motor-generator, The control unit supplies power to the electric supercharger obtained by supplying the fuel cell's emissions to one of the first motor-generator and the second motor-generator, based on at least one of information indicating the operating status of the gas turbine engine and the amount of power demanded within the machine. The aircraft hybrid power source system according to claim 2 or 4.

6. Equipped on aircraft, fuel gas for fuel cells is generated from raw materials by heating with exhaust gas from a gas turbine engine, which includes low-pressure and high-pressure shafts as rotating shafts. The fuel gas is supplied to the fuel cell. Based on information indicating the operating status of the gas turbine engine and the power demand of the aircraft, the power of the fuel cell obtained by supplying the fuel gas is supplied to one of the first motor-generator connected to the high-voltage shaft and the second motor-generator connected to the low-voltage shaft. A method for controlling an aircraft hybrid power source system.

7. Heat exchange between the fuel gas supplied to the fuel cell and the emissions from the fuel cell heats the emissions from the fuel cell and cools the fuel gas. By supplying the exhaust from the heated fuel cell to the turbine of the supercharger, the oxidizer gas of the fuel cell is compressed and supplied to the fuel cell from the compressor of the supercharger. A control method for an aircraft hybrid power source system according to claim 6.

8. Before generating the fuel gas from the raw materials, the raw materials are heated. A control method for an aircraft hybrid power source system according to claim 6.

9. The fuel cell is equipped on an aircraft and pressurizes the fuel cell's exhaust gas by heating it using heat exchange between the exhaust gas from the gas turbine engine, which includes a low-pressure shaft and a high-pressure shaft as rotating shafts, and the fuel cell's exhaust gas. The exhaust from the fuel cell, which has been pressurized, is supplied to the turbine of the supercharger. The fuel gas discharged from the compressor of the supercharger is supplied to the fuel cell. Based on information indicating the operating status of the gas turbine engine and the power demand of the aircraft, the power of the fuel cell obtained by supplying the fuel gas is supplied to one of the first motor-generator connected to the high-voltage shaft and the second motor-generator connected to the low-voltage shaft. A method for controlling an aircraft hybrid power source system.

10. The supercharger is an electric supercharger equipped with a third motor-generator, The power of the electric supercharger obtained by supplying the emissions from the fuel cell is supplied to one of the first motor generator and the second motor generator. A control method for an aircraft hybrid power source system according to claim 7 or 9.

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