Hybrid aircraft propulsion system

Abstract

This hybrid aircraft propulsion system comprises: a fan; a gas turbine engine including a compressor, a combustor, a turbine, and an engine rotation shaft that mechanically connects the turbine to the compressor; an electric motor including a motor rotation shaft that is mechanically connected to the fan and the engine rotation shaft in a state of being interposed between the fan and the engine rotation shaft; and a clutch that can disconnect the mechanical connection between the fan and the motor rotation shaft.

Description

Hybrid aircraft propulsion system

[0004]

[0001] This disclosure relates to a propulsion system for a hybrid aircraft comprising a gas turbine engine and an electric motor.

[0002] Patent Document 1 discloses a propulsion device for an aircraft comprising a propeller driven by an electric motor. This propulsion device further comprises a boost section composed of a compressor, a combustion chamber and an exhaust nozzle, and the compressor is driven by an electric motor via a clutch. The boost section does not comprise a turbine, and propulsion force is generated by combustion gas from the combustion chamber being ejected through the exhaust nozzle.

[0003] GB2612973A

[0004] In this propulsion device, since the fan is driven only by an electric motor, power consumption increases and the flight range may be shortened.

[0005] Therefore, one aspect of the present disclosure aims to provide an efficient propulsion system that can increase the flight range of an aircraft while reducing power consumption.

[0006] A hybrid aircraft propulsion system according to one aspect of the present disclosure comprises a fan, a gas turbine engine including a compressor, a combustor, a turbine, and an engine rotating shaft that mechanically connects the turbine to the compressor, and an electric motor including a motor rotating shaft that is mechanically connected to the fan and the engine rotating shaft while being interposed between the fan and the engine rotating shaft, and a clutch capable of disconnecting the mechanical connection between the fan and the motor rotating shaft.

[0007] According to one aspect of the present disclosure, an efficient propulsion system that can increase the flight range of an aircraft while reducing power consumption can be provided.

[0008] Figure 1 is a schematic diagram of a hybrid aircraft propulsion system according to the first embodiment. Figure 2 is a block diagram of the control system of the aircraft propulsion system in Figure 1. Figure 3 is a diagram illustrating each state of the aircraft propulsion system in Figure 1. Figure 4 is a schematic diagram of a hybrid aircraft propulsion system according to the second embodiment. Figure 5 is a schematic diagram of a hybrid aircraft propulsion system according to the third embodiment.

[0009] The embodiments will be described below with reference to the drawings.

[0010] In the following explanation, the direction in which the axis X of the engine rotation shaft 34 of the thrust generator 2 extends can be referred to as the axial direction X. "Front" and "front side" mean the upstream side in the direction in which air flows through the fan 3 and the gas turbine engine 6, and "rear" and "rear side" mean the downstream side in the direction in which air flows through the fan 3 and the gas turbine engine 6. That is, "front" and "front side" mean the side of the thrust generator 2 on which the fan 3 is located in the axial direction X, and "rear" and "rear side" mean the side of the thrust generator 2 on the opposite side from the side on which the fan 3 is located in the axial direction X. The radial direction means the direction perpendicular to the axis X.

[0011] (First Embodiment) Figure 1 is a schematic diagram of a hybrid aircraft propulsion system 1 according to the first embodiment. As shown in Figure 1, the hybrid aircraft propulsion system 1 is mounted on an aircraft 10 to generate thrust for the aircraft 10. The hybrid aircraft propulsion system 1 includes a thrust generator 2. The thrust generator 2 includes a fan 3, a duct 4, an inner casing 5, a gas turbine engine 6, an electric motor 7, a reduction gear 8, a first clutch 11, a second clutch 12, a first clutch actuator 13, and a second clutch actuator 14.

[0012] The fan 3 is located in front of the thrust generator 2. The duct 4 has a cylindrical shape. The front part of the duct 4 surrounds the fan 3 from the radially outer side. The inner shell 5 has a cylindrical shape. The inner shell 5 is located behind the fan 3 and radially inward of the duct 4. The gas turbine engine 6 is located radially inward of the rear of the inner shell 5. The rear part of the inner shell 5 serves as the casing for the gas turbine engine 6.

[0013] The gas turbine engine 6 includes a compressor 31, a combustor 32, a turbine 33, and an engine rotating shaft 34. The gas turbine engine 6 can also be called a gas generator. The combination of the fan 3 and the gas turbine engine 6 can also be called a turbofan engine. The gas turbine engine 6 is, for example, a single-shaft engine. The compressor 31, combustor 32, and turbine 33 are arranged in this order from front to rear in the axial direction X. The engine rotating shaft 34 mechanically connects the turbine 33 to the compressor 31. The rotational force of the turbine 33 is transmitted to the compressor 31 via the engine rotating shaft 34, thereby driving the compressor 31.

[0014] The compressor 31 compresses the inhaled air and supplies the compressed air to the combustor 32. The combustor 32 burns the fuel supplied by the electric fuel pump 35 and ejects combustion gas. The electric fuel pump 35 supplies the fuel stored in the fuel tank 18 to the combustor 32. The fuel stored in the fuel tank 18 is, for example, hydrogen fuel. In other words, the gas turbine engine 6 is, for example, a hydrogen engine. The turbine 33 rotates due to the combustion gas ejected from the combustor 32. Alternatively, instead of the electric fuel pump 35, a mechanical fuel pump driven in conjunction with the engine's rotating shaft 34 may be used.

[0015] The electric motor 7 includes a motor housing that houses a stator and a rotor, and a motor rotating shaft 41 connected to the rotor within the motor housing. The motor rotating shaft 41 functions as a drive shaft in the driving state and as an input shaft in the power generation state. The electric motor 7 is positioned between the fan 3 and the gas turbine engine 6 in the axial direction X. It can also be said that the electric motor 7 is built into the turbofan engine, which is a combination of the fan 3 and the gas turbine engine 6. For example, the maximum output of the electric motor 7 is less than the maximum output of the gas turbine engine 6.

[0016] The motor rotating shaft 41 is arranged to be mechanically connectable to the fan 3 and the engine rotating shaft 34 by a first clutch 11 and a second clutch 12, which will be described later. The motor rotating shaft 41 is arranged in series with the engine rotating shaft 34 in the power transmission path between the engine rotating shaft 34 and the fan 3. The motor rotating shaft 41 is arranged coaxially with the engine rotating shaft 34, for example. However, the motor rotating shaft 41 does not have to be arranged coaxially with the engine rotating shaft 34 as long as it can be mechanically connected to the engine rotating shaft 34 in a way that allows for power transmission. Multiple gears may be interposed in the power transmission path between the engine rotating shaft 34 and the motor rotating shaft 41.

[0017] The reduction gear 8 is positioned between the fan 3 and the motor rotating shaft 41 in the axial direction X. The reduction gear 8 is positioned to be mechanically connectable to the fan 3 and the motor rotating shaft 41. The reduction gear 8 is positioned in series with the engine rotating shaft 34 and the motor rotating shaft 41 in the power transmission path between the engine rotating shaft 34 and the fan 3. The reduction gear 8 reduces the driving force from the motor rotating shaft 41 toward the fan 3.

[0018] The first clutch 11 is positioned between the fan 3 and the motor rotating shaft 41. Specifically, the first clutch 11 is positioned between the reduction gear 8 and the motor rotating shaft 41. That is, the first clutch 11 can disconnect the mechanical connection between the reduction gear 8 and the motor rotating shaft 41. The first clutch actuator 13 drives the first clutch 11 to switch between a connected state and a disconnected state. The first clutch actuator 13 may be, for example, an electromagnetic actuator, a hydraulic actuator, or a pneumatic actuator.

[0019] When the first clutch 11 is engaged, the driving force of the motor shaft 41 is input to the reduction gear 8, and the driving force output from the reduction gear 8 rotates the fan 3. When the first clutch 11 is disengaged, the fan 3 and the reduction gear 8 are mechanically separated from the motor shaft 41, and the load of the fan 3 is not transmitted to the motor shaft 41.

[0020] The second clutch 12 is positioned between the engine rotating shaft 34 and the motor rotating shaft 41. That is, the second clutch 12 can disconnect the mechanical connection between the engine rotating shaft 34 and the motor rotating shaft 41. The second clutch actuator 14 drives the second clutch 12 to switch between the engaged state and the disengaged state. The second clutch actuator 14 may also be, for example, an electromagnetic actuator, a hydraulic actuator, or a pneumatic actuator.

[0021] When the second clutch 12 is engaged, the engine rotating shaft 34 and the motor rotating shaft 41 transmit driving force to each other. The motor rotating shaft 41 rotates together with the engine rotating shaft 34. For example, the motor rotating shaft 41 is connected to the engine rotating shaft 34 at a constant speed. In this case, the rotational speed of the motor rotating shaft 41 matches the rotational speed of the engine rotating shaft 34. If the rotational speed of the electric motor 7 is high, the required torque of the electric motor 7 decreases, so a smaller motor can be used for the electric motor 7. When the second clutch 12 is disengaged, the engine rotating shaft 34 is mechanically separated from the motor rotating shaft 41, and the engine rotating shaft 34 does not provide resistance to the rotation of the motor rotating shaft 41.

[0022] An inverter 15 is electrically connected to the electric motor 7. The inverter 15 may be built into the electric motor 7. The inverter 15 is electrically connected to a battery 16 and a fuel cell 17. That is, the inverter 15 supplies power to the electric motor 7 from at least one of the battery 16 and the fuel cell 17. The fuel cell 17 is configured to generate electricity through a chemical reaction between hydrogen and oxygen. The fuel cell 17 takes in hydrogen from the fuel tank 18 and oxygen from the air. This allows the fuel cell 17 to generate electricity by effectively utilizing hydrogen fuel intended for aircraft.

[0023] Furthermore, if the fuel tank 18 stores jet fuel, a separate hydrogen tank may be provided in addition to the fuel tank 18, and hydrogen may be supplied from that hydrogen tank to the fuel cell 17. The fuel cell 17 may also be configured in other ways. For example, the jet fuel in the fuel tank 18 for the gas turbine engine 6 may be reformed and supplied to the fuel cell. The fuel cell 17 may also be omitted.

[0024] The hybrid aircraft propulsion system 1 comprises an engine controller 20, a motor controller 21, an airframe controller 22, and an integrated controller 23. The engine controller 20 controls the gas turbine engine 6. For example, the engine controller 20 drives the gas turbine engine 6 by controlling the electric fuel pump 35 of the gas turbine engine 6. The motor controller 21 controls the inverter 15 connected to the electric motor 7. That is, the motor controller 21 controls the electric motor 7 via the inverter 15. The airframe controller 22 controls the airframe of the aircraft 10.

[0025] The integrated controller 23 receives signals from the engine controller 20, motor controller 21, and aircraft controller 22, and issues commands to the engine controller 20, motor controller 21, and aircraft controller 22. The integrated controller 23 also controls the first clutch actuator 13 and the second clutch actuator 14.

[0026] Controllers 20, 21, 22, and 23 each include a control circuit. Specifically, each of controllers 20, 21, 22, and 23 includes a processor and memory. The processor may include, for example, a CPU (Central Processing Unit). The memory may include, for example, system memory and storage memory. The system memory may include, for example, RAM. The storage memory may include, for example, ROM. The storage memory may include a hard disk, flash memory, or a combination thereof. The storage memory stores the control program.

[0027] In each of the controllers 20, 21, 22, and 23, a configuration in which the processor executes a control program read from the system memory is an example of a control circuit. The processing circuit 25 of the hybrid aircraft propulsion system 1 may mean the entirety of each control circuit of each controller 20, 21, and 23, or it may mean at least one of each control circuit of the controllers 20, 21, and 23. At least two of the controllers 20, 21, 22, and 23 may be integrated into one.

[0028] Figure 2 is a block diagram of the control system of the aircraft propulsion system 1 shown in Figure 1. As shown in Figure 2, the engine controller 20 is communicatively connected to the rotational speed sensor 51, pressure sensor 52, temperature sensor 53, and integrated controller 23. The rotational speed sensor 51 detects the rotational speed of the engine rotating shaft 34. The pressure sensor 52 detects the inlet air pressure of the gas turbine engine 6. A pressure sensor for detecting the outlet pressure of the compressor 31 may also be provided. The temperature sensor 53 detects the inlet air temperature of the gas turbine engine 6. A temperature sensor for detecting the exhaust gas temperature of the gas turbine engine 6 may also be provided. The integrated controller 23 transmits start commands, stop commands, emergency operation commands, etc., to the engine controller 20. The engine controller 20 controls the electric fuel pump 35 in response to commands from the integrated controller 23 and signals from each of the sensors 51, 52, and 53.

[0029] In the gas turbine engine 6, the high-efficiency torque range is determined by the rotational speed of the engine shaft 34. The engine controller 20 stores a torque map in which torque rules are defined that show the relationship between rotational speed and the high-efficiency target torque. The target torque in the torque map is associated with a command value to the electric fuel pump 35. When the aircraft 10 is cruising, the engine controller 20 performs engine torque control, which feedforward controls the electric fuel pump 35 according to the target torque determined based on the torque map.

[0030] The engine controller 20 sets the fuel supply amount from the electric fuel pump 35 to the combustor 32 to a constant level in order to keep the output torque of the gas turbine engine 6 constant in the high-efficiency operating range when the rotational speed of the engine shaft 34 is constant. However, the output torque of the gas turbine engine 6 changes depending on the inlet air pressure and inlet air temperature of the gas turbine engine 6. Therefore, the engine controller 20 may store an adjustment map that defines the adjustment rules for the electric fuel pump 35 according to the inlet air pressure and inlet air temperature.

[0031] The adjustment map records the correction amounts for the command values ​​to the electric fuel pump 35, corresponding to the inlet air pressure and inlet air temperature. The engine controller 20 then refers to this adjustment map, obtains the correction amounts for the command values ​​to the electric fuel pump 35 corresponding to the values ​​detected by the pressure sensor 52 and the temperature sensor 53, and can feedforward control the electric fuel pump 35 using the command values ​​corrected by these correction amounts.

[0032] The motor controller 21 is communicatively connected to the integrated controller 23, the rotation speed sensor 54, and the rotation speed sensor 55. The integrated controller 23 transmits start commands, stop commands, emergency operation commands, etc., to the motor controller 21. The rotation speed sensor 54 detects the rotation speed of the motor rotation shaft 41. The rotation speed sensor 55 detects the rotation speed of the fan 3. The motor controller 21 controls the inverter 15 in accordance with commands from the integrated controller 23 and signals from each of the sensors 54 and 55.

[0033] During the cruising flight of the aircraft 10, the motor controller 21 provides feedback control to the inverter 15 to adjust the output of the electric motor 7 so that the rotational speed of the fan 3 reaches the requested rotational speed commanded by the integrated controller 23, while controlling the engine torque of the gas turbine engine 6. Therefore, by adjusting the output of the electric motor 7 when the environment surrounding the aircraft 10 or the required thrust changes, the fan 3 can be rotated at the requested rotational speed even while the gas turbine engine 6 is operating in the high-efficiency range.

[0034] The motor controller 21 normally controls the inverter 15 to supply power to the electric motor 7 from both the battery 16 and the fuel cell 17. When the torque required by the electric motor 7 meets a predetermined increase condition, the motor controller 21 performs motor high-power control. In this motor high-power control, the inverter 15 is controlled to increase the output of the electric motor 7 and to increase the ratio of the current output from the battery 16 to the current output from the fuel cell 17.

[0035] The aforementioned increase condition may include the condition that the motor controller 21 determines that the rate of increase in the torque required for the electric motor 7 exceeds a threshold. In high-power motor control, the inverter 15 is controlled so that the discharge amount of the battery 16 increases, so that even when rapid acceleration is required for the electric motor 7, a large amount of current can be quickly supplied to the electric motor 7, and the propulsion force can be stabilized.

[0036] The motor controller 21 may terminate the motor high-power control after a predetermined timer period has elapsed since the motor high-power control started. Alternatively, the motor controller 21 may terminate the motor high-power control if the remaining charge of the battery 16 falls below a predetermined value while the motor high-power control is being executed.

[0037] The integrated controller 23 controls the first clutch actuator 13 and the second clutch actuator 14, and switches the first clutch 11 and the second clutch 12 between a connected state and a disconnected state. The integrated controller 23 receives commands from the pilot operating the aircraft 10.

[0038] Figure 3 is a diagram illustrating the various operating states of the aircraft propulsion system 1 shown in Figure 1. As shown in Figure 3, the operating states of the aircraft 10 are described as taxiing, starting, ground power generation, takeoff-climb flight, cruising, and descent flight. In the following description, the statement that the clutch actuator is controlled to disengage the clutch includes not only switching the clutch from an engaged state to a disengaged state, but also maintaining a clutch that is normally in a disengaged state in a disengaged state. In Figure 3, the clutch engaged state is indicated as ON, and the clutch disengaged state is indicated as OFF.

[0039] [Taxiing] When the aircraft 10 is on the ground, the integrated controller 23, upon receiving a taxiing command from the pilot, controls the first clutch actuator 13 to engage the first clutch 11 and controls the second clutch actuator 14 to disengage the second clutch 12. Furthermore, the integrated controller 23 commands the motor controller 21 to drive the electric motor 7 (state (3) in Figure 3). At this time, the state of the gas turbine engine 6 is not particularly limited; the gas turbine engine 6 may be stopped or idling. In particular, stopping the gas turbine engine 6 can further reduce fuel consumption.

[0040] Since the engine rotating shaft 34 is mechanically separated from the motor rotating shaft 41, the electric motor 7 drives the fan 3 without being subjected to the resistance of the gas turbine engine 6, and taxiing is performed. With this motor taxiing, starting the gas turbine engine 6 is unnecessary, so taxiing can be performed quickly by the electric motor 7, and the gas turbine engine 6 does not have to be operated in an inefficient range.

[0041] Incidentally, the integrated controller 23 may control the first clutch actuator 13 and the second clutch actuator 14 to connect the first clutch 11 and the second clutch 12, and use the driving force of the gas turbine engine 6 to taxi the aircraft 10. During this engine taxiing, the electric motor 7 may be in a driving state or a regenerative state. For example, when it is determined that the remaining amount of the battery 16 is less than a predetermined value, taxiing may be performed using the driving force of the gas turbine engine 6. In this example, if the electric motor 7 is in a regenerative state during taxiing by the gas turbine engine 6, it is preferable because the battery 16 can be charged.

[0042] [Start] When the integrated controller 23 receives an engine start command from the pilot, it controls the first clutch actuator 13 to disconnect the first clutch 11 and controls the second clutch actuator 14 to connect the second clutch 12. Further, the integrated controller 23 commands the motor controller 21 to drive the electric motor 7 and commands the engine controller 20 to supply fuel from the electric fuel pump 35 to the combustor 32 in a state where the engine rotary shaft 34 starts to rotate by the electric motor 7 (state (4) in FIG. 3).

[0043] Since the first clutch 11 is in a disconnected state, the electric motor 7 can drive the engine rotary shaft 34 without receiving the mechanical resistance of the fan 3 and can serve as a starter motor. Therefore, it is possible to prevent the electric motor 7 from becoming large-sized for the starter function. Further, since the electric motor 7 also serves as a starter motor, the fuel consumption of the APU (auxiliary power unit) or the operation opportunity of the APU can be reduced.

[0044] Incidentally, the integrated controller 23 may control the first clutch actuator 13 and the second clutch actuator 14 to disconnect the first clutch 11 and the second clutch 12, and start the gas turbine engine 6 by the APU. For example, when it is determined that the remaining amount of the battery 16 is less than a predetermined value, the gas turbine engine 6 may be started by the APU without using the electric motor 7.

[0045] [Ground Power Generation] When the aircraft 10 is on the ground, if the integrated controller 23 receives a ground power generation command from the pilot or determines that it is necessary to charge the battery 16, it controls the first clutch actuator 13 to disengage the first clutch 11 and controls the second clutch actuator 14 to engage the second clutch 12. Further, the integrated controller 23 commands the engine controller 20 to start the gas turbine engine 6 and commands the motor controller 21 to cause the electric motor 7 to generate electricity (state (5) in FIG. 3).

[0046] Since the first clutch 11 is disengaged, the gas turbine engine 6 can drive the electric motor 7 without being affected by the resistance of the fan 3, enabling power generation with reduced energy loss. This ground power generation function can be suitably used in an example where the aircraft 10 does not carry the fuel cell 17.

[0047] [Takeoff and Climbing Flight] When the integrated controller 23 receives a high-power output command requesting that the output of the thrust generator 2 exceed a predetermined value for takeoff and climbing flight of the aircraft 10 based on the pilot's input, it controls the first clutch actuator 13 and the second clutch actuator 14 to engage the first clutch 11 and the second clutch 12. Further, the integrated controller 23 commands the engine controller 20 to drive the gas turbine engine 6 and commands the motor controller 21 to drive the electric motor 7 (state (1) in FIG. 3).

[0048] Since the first clutch 11 and the second clutch 12 are engaged, the fan 3 can be rotated at high speed by the driving forces of both the gas turbine engine 6 and the electric motor 7, allowing the aircraft 10 to take off and climb smoothly. Note that the integrated controller 23 may drive the fan 3 only with the gas turbine engine 6 without using the driving force of the electric motor 7 for takeoff and climbing flight. In that case, the motor controller 21 may control the inverter 15 to open the circuit of the electric motor 7 so that the electric motor 7 rotates freely.

[0049] [Cruising] After the aircraft 10 has taken off and completed its climb, the integrated controller 23, upon receiving a cruising command from the pilot, controls the first clutch actuator 13 and the second clutch actuator 14 to control the first clutch 11 and the second clutch actuator 14 to maintain the first clutch 11 and the second clutch 12 in a engaged state. Furthermore, the integrated controller 23 commands the engine controller 20 to drive the gas turbine engine 6 and commands the motor controller 21 to drive the electric motor 7 (State (1) in Figure 3).

[0050] During cruising, it is preferable that the gas turbine engine 6 and the electric motor 7 are controlled such that the output torque of the gas turbine engine 6 is greater than the output torque of the electric motor 7. That is, during cruising, by engaging the first clutch 11 and the second clutch 12, the fan 3, which is mainly driven by the driving force of the gas turbine engine 6, can also be driven by the assist driving force of the electric motor 7.

[0051] Specifically, during cruising flight of the aircraft 10, the engine controller 20 performs engine torque control by feedforward control of the electric fuel pump 35 according to a target torque determined based on the torque map, while the motor controller 21 adjusts the output of the electric motor 7 by feedback control of the inverter 15 so that the rotational speed of the fan 3 becomes the requested rotational speed commanded by the integrated controller 23. By adjusting the output of the electric motor 7 in this way, the fan 3 can be rotated at the requested rotational speed while the gas turbine engine 6 is operating in the high-efficiency range.

[0052] Therefore, energy efficiency can be increased while maintaining the propulsion performance of the thrust generator 2, reducing power consumption and extending the range of the aircraft 10. In addition, since the difference between maximum thrust and cruising thrust can be filled by the driving force of the electric motor 7, the gas turbine engine 6 can be made smaller to suit cruising conditions.

[0053] During cruising flight of the aircraft 10, if the load on the gas turbine engine 6 decreases due to changes in the surrounding environment or required thrust while engine torque control is being performed, and the rotational speed of the fan 3 becomes greater than the required rotational speed, the integrated controller 23 commands the motor controller 21 to put the electric motor 7 into a regenerative state (State (2) in Figure 3). By utilizing the regeneration of the electric motor 7 in this way, even when the load on the gas turbine engine 6 decreases, the fan 3 can be rotated at the required rotational speed while the gas turbine engine 6 remains operating at its rated speed in the high-efficiency range. Therefore, energy efficiency can be increased while maintaining the propulsion performance of the thrust generator 2.

[0054] [Descent Flight] When the integrated controller 23 receives a low-power command from the pilot requesting that the output of the thrust generator 2 be below a predetermined value in preparation for the aircraft 10's descent for landing, it controls the first clutch actuator 13 to engage the first clutch 11 and controls the second clutch actuator 14 to disengage the second clutch 12. Furthermore, the integrated controller 23 commands the engine controller 20 to stop the gas turbine engine 6 and commands the motor controller 21 to drive the electric motor 7 (State (3) in Figure 3).

[0055] When the rotational speed required for the fan 3 is low, such as during the descent of the aircraft 10, stopping the gas turbine engine 6 prevents the gas turbine engine 6 from operating in an inefficient range. Furthermore, by disengaging the second clutch 12, the electric motor 5 can drive the fan 3 without being affected by the mechanical resistance of the stopped gas turbine engine 6, thereby reducing energy loss.

[0056] (Second Embodiment) Figure 4 is a schematic diagram of the hybrid aircraft propulsion system 101 according to the second embodiment. Components common to the first embodiment are denoted by the same reference numerals and their descriptions are omitted. As shown in Figure 4, the hybrid aircraft propulsion system 101 mounted on the aircraft 110 of this embodiment includes a supercharger 161 in the gas turbine engine 6 of the thrust generator 102. The supercharger 161 is driven by the energy generated by the gas turbine engine 6. The supercharger 161 is, for example, a turbocharger.

[0057] The supercharger 161 is in communication with the turbine 33 of the gas turbine engine 6. The supercharger 161 is driven by the combustion gases discharged from the turbine 33 of the gas turbine engine 6 to generate compressed air. The supercharger 161 may also be a supercharger that is mechanically driven by the engine rotating shaft 34 of the gas turbine engine 6.

[0058] The supercharger 161 is connected to the intake side of the compressor 31 via a compressed air passage 162. The compressed air passage 162 is provided with a first valve 163 that opens and closes the passage from the supercharger 161 to the compressor 31. The first valve 163 is, for example, an electromagnetic valve. The opening and closing of the first valve 163 is controlled by the integrated controller 23. When the first valve 163 is opened during operation of the gas turbine engine 6, compressed air from the supercharger 161 is supplied to the compressor 31 of the gas turbine engine 6. This improves the efficiency of the gas turbine engine 6.

[0059] Furthermore, the compressed air passage 162 connects the supercharger 161 to the fuel cell 17. The compressed air passage 162 is provided with a second valve 164 that opens and closes the passage from the supercharger 161 to the fuel cell 17. The second valve 164 is, for example, an electromagnetic valve. The second valve 164 is controlled to open and close by the integrated controller 23. When the second valve 164 is opened during the operation of the gas turbine engine 6, compressed air from the supercharger 161 is supplied to the fuel cell 17. This increases the amount of oxygen supplied to the fuel cell 17, thereby improving the power generation efficiency of the fuel cell 17. One or both of the first valve 163 and the second valve 164 may be open, or both may be closed. Note that the other configurations are the same as those of the first embodiment described above, so their description is omitted.

[0060] (Third Embodiment) Figure 5 is a schematic diagram of the hybrid aircraft propulsion system 201 according to the third embodiment. Components common to the first embodiment are denoted by the same reference numerals and their descriptions are omitted. As shown in Figure 5, the hybrid aircraft propulsion system 201 mounted on the aircraft 210 of this embodiment includes a compressed air passage 271 that guides compressed air generated by the compressor 31 of the gas turbine engine 6 of the thrust generator 202 to the fuel cell 17. The compressed air passage 271 is provided with a valve 272 that opens and closes the compressed air passage 271. The valve 272 is, for example, an electromagnetic valve. The valve 272 is controlled to open and close by an integrated controller 23.

[0061] When the valve 272 is opened while the gas turbine engine 6 is in operation, compressed air extracted from the compressor 31 of the gas turbine engine 6 is supplied to the fuel cell 17. This increases the amount of oxygen supplied to the fuel cell 17, thereby improving the efficiency of the fuel cell 17. The other configurations are the same as those of the first embodiment described above, so their explanation is omitted.

[0062] As described above, the embodiments have been explained as examples of the technology disclosed in this application. However, the technology in this disclosure is not limited to these embodiments and can be applied to embodiments that have been modified, replaced, added, or omitted as appropriate. Furthermore, it is possible to combine the components described in the embodiments to create new embodiments. For example, some components or methods in one embodiment may be applied to other embodiments, and some components in an embodiment can be separated from other components in that embodiment and extracted as appropriate. In addition, the components described in the attached drawings and detailed description include not only components that are essential for solving the problem, but also components that are not essential for solving the problem, in order to illustrate the technology.

[0063] The functions of the elements disclosed herein can be performed using circuits or processing circuits, including general-purpose processors, dedicated processors, integrated circuits, ASICs (Application Specific Integrated Circuits), FPGAs (Field Programmable Gate Arrays), GPUs (Graphics Processing Units), conventional circuits, and / or combinations thereof, configured or programmed to perform the disclosed functions. A processor is considered a processing circuit or circuit because it includes transistors and other circuits. In this disclosure, a circuit, unit, or means is hardware that performs the enumerated functions, or hardware programmed to perform the enumerated functions. The hardware may be hardware disclosed herein, or other known hardware that is programmed or configured to perform the enumerated functions. If the hardware is a processor, which is considered a type of circuit, then the circuit, means, or unit is a combination of hardware and software, and the software is used to configure the hardware and / or the processor.

[0064] [Embodiment] The embodiments described above are specific examples of the following embodiments.

[0065] (Aspect 1) A hybrid aircraft propulsion system comprising: a fan; a gas turbine engine including a compressor, a combustor, a turbine, and an engine rotating shaft that mechanically connects the turbine to the compressor; an electric motor including a motor rotating shaft that is interposed between the fan and the engine rotating shaft and mechanically connected to the fan and the engine rotating shaft; and a clutch that can disconnect the mechanical connection between the fan and the motor rotating shaft.

[0066] With this configuration, by disengaging the clutch, the engine's rotating shaft can be driven by the electric motor's force without the mechanical resistance of the fan, thereby starting the gas turbine engine. After the engine starts, by engaging the clutch, the fan's drive, powered by the gas turbine engine, can be assisted by the motor's rotating shaft's force. Therefore, an efficient propulsion system can be provided that reduces power consumption while extending the aircraft's range.

[0067] (Aspect 2) The hybrid aircraft propulsion system according to aspect 1, wherein the clutch is a first clutch, and the system further comprises a second clutch capable of disconnecting the mechanical connection between the engine rotating shaft and the motor rotating shaft.

[0068] This configuration allows for diverse drive control tailored to different situations by selectively combining the states of the first clutch and the second clutch.

[0069] (Aspect 3) The hybrid aircraft propulsion system according to aspect 2, further comprising: a first clutch actuator for switching the first clutch between a connected state and a disconnected state; a second clutch actuator for switching the second clutch between a connected state and a disconnected state; and a processing circuit for controlling the gas turbine engine, the electric motor, the first clutch actuator, and the second clutch actuator, wherein the processing circuit is configured to control the first clutch actuator and the second clutch actuator to connect the first clutch and disconnect the second clutch, and to control the electric motor to rotate the fan by the driving force of the motor's rotating shaft.

[0070] This configuration allows for easy and rapid aircraft taxiing using electric motors. Furthermore, when the rotational speed required for the fan is low, such as during aircraft descent, the aircraft's thrust can be adjusted using electric motors.

[0071] (Aspect 4) A hybrid aircraft propulsion system according to any one of aspects 1 to 3, further comprising: a clutch actuator for switching the clutch between a connected state and a disconnected state; and a processing circuit for controlling the gas turbine engine, the electric motor, and the clutch actuator, wherein the processing circuit is configured to control the electric motor and the gas turbine engine to start the gas turbine engine while the clutch actuator is in a disconnected state.

[0072] This configuration allows the gas turbine engine to be started easily.

[0073] (Aspect 5) A hybrid aircraft propulsion system according to any one of aspects 1 to 4, further comprising: a clutch actuator for switching the clutch between a connected state and a disconnected state; and a processing circuit for controlling the gas turbine engine, the electric motor, and the clutch actuator, wherein the processing circuit is configured to control the clutch actuator to connect the clutch, and then to control the gas turbine engine to rotate the fan using the driving force of the engine's rotating shaft.

[0074] With this configuration, thrust can be easily obtained by driving a fan with a gas turbine engine.

[0075] (Aspect 6) The hybrid aircraft propulsion system according to aspect 5, wherein the processing circuit is configured to acquire the rotational speed of the gas turbine engine, to perform engine torque control to control the gas turbine engine according to a target torque determined based on a torque rule showing the relationship between rotational speed and torque in the gas turbine engine, and to control the electric motor so that the rotational speed of the fan approaches a required rotational speed during the execution of the engine torque control.

[0076] This configuration allows the gas turbine engine to operate efficiently by determining the target torque corresponding to its rotational speed by referring to torque rules, while simultaneously driving the fan at the required rotational speed using an electric motor. Therefore, energy efficiency can be increased while maintaining propulsion performance. Furthermore, since the difference between maximum thrust and cruising thrust can be filled with the driving force of the electric motor, the gas turbine engine can be sized appropriately for cruising.

[0077] (Aspect 7) The hybrid aircraft propulsion system according to aspect 5 or 6, wherein the processing circuit is configured to put the electric motor into a power generation state.

[0078] With this configuration, electricity can be generated while the fan is rotated by the driving force of the engine's rotating shaft. Furthermore, by maintaining the gas turbine engine in a highly efficient state while the fan is driven at the required rotational speed by regenerative braking from an electric motor, energy efficiency can be increased while maintaining propulsion performance.

[0079] (Aspect 8) A hybrid aircraft propulsion system according to any one of aspects 1 to 7, further comprising: a clutch actuator for switching the clutch between a connected state and a disconnected state; a processing circuit for controlling the gas turbine engine, the electric motor, and the clutch actuator, wherein the processing circuit is configured to control the clutch actuator to keep the clutch in a disconnected state, and then to control the gas turbine engine to drive the electric motor with the driving force of the engine's rotating shaft, thereby causing the electric motor to generate electricity.

[0080] This configuration allows for efficient power generation by driving an electric motor with a gas turbine engine without the mechanical resistance of a fan.

[0081] (Aspect 9) A hybrid aircraft propulsion system according to any one of aspects 1 to 8, further comprising: a fuel tank for storing hydrogen fuel; and a fuel cell for generating electricity using hydrogen fuel from the fuel tank and extracted air from the compressor of the gas turbine engine.

[0082] This configuration allows for the effective use of hydrogen fuel intended for aircraft to generate electricity, improves power generation efficiency by supplying extracted gas from the compressor to the fuel cell, and enables the fuel cell to be miniaturized.

[0083] (Aspect 10) The hybrid aircraft propulsion system according to aspect 9, further comprising: a battery; an inverter that supplies power from the battery and the fuel cell to the electric motor; and a processing circuit that controls the inverter, wherein the processing circuit is configured to control the inverter to increase the ratio of the current output from the battery to the current output from the fuel cell when the torque required for the electric motor satisfies a predetermined increase condition.

[0084] With this configuration, even if the electric motor is required to accelerate rapidly in an emergency, a large amount of current can be quickly supplied from the battery to the electric motor, stabilizing the propulsion force.

[0085] 1,101,201 Hybrid Aircraft Propulsion System 3 Fan 6 Gas Turbine Engine 7 Electric Motor 10 Aircraft 11 First Clutch 12 Second Clutch 13 First Clutch Actuator 14 Second Clutch Actuator 15 Inverter 16 Battery 17 Fuel Cell 18 Fuel Tank 25 Processing Circuit 31 Compressor 32 Combustor 33 Turbine 34 Engine Rotating Shaft 41 Motor Rotating Shaft

Claims

1. A hybrid aircraft propulsion system comprising: a gas turbine engine including a fan, a compressor, a combustor, a turbine, and an engine rotating shaft that mechanically connects the turbine to the compressor; an electric motor including a motor rotating shaft that is interposed between the fan and the engine rotating shaft and mechanically connected to the fan and the engine rotating shaft; and a clutch that can disconnect the mechanical connection between the fan and the motor rotating shaft.

2. The hybrid aircraft propulsion system according to claim 1, wherein the clutch is a first clutch, and the system further comprises a second clutch capable of disconnecting the mechanical connection between the engine rotating shaft and the motor rotating shaft.

3. The hybrid aircraft propulsion system according to claim 2, further comprising: a first clutch actuator for switching the first clutch between a connected state and a disconnected state; a second clutch actuator for switching the second clutch between a connected state and a disconnected state; and a processing circuit for controlling the gas turbine engine, the electric motor, the first clutch actuator, and the second clutch actuator, wherein the processing circuit is configured to control the electric motor to rotate the fan by the driving force of the motor's rotating shaft while the first clutch actuator and the second clutch actuator are in a connected state and the second clutch is in a disconnected state.

4. The hybrid aircraft propulsion system according to claim 1, further comprising: a clutch actuator for switching the clutch between a engaged state and a disengaged state; and a processing circuit for controlling the gas turbine engine, the electric motor, and the clutch actuator, wherein the processing circuit is configured to control the electric motor and the gas turbine engine to start the gas turbine engine while the clutch actuator is in a disengaged state.

5. The hybrid aircraft propulsion system according to claim 1, further comprising: a clutch actuator for switching the clutch between a engaged state and a disengaged state; and a processing circuit for controlling the gas turbine engine, the electric motor, and the clutch actuator, wherein the processing circuit is configured to control the clutch actuator to engage the clutch, and then to control the gas turbine engine to rotate the fan using the driving force of the engine's rotating shaft.

6. The hybrid aircraft propulsion system according to claim 5, wherein the processing circuit is configured to: acquire the rotational speed of the gas turbine engine; perform engine torque control to control the gas turbine engine according to a target torque determined based on a torque rule showing the relationship between rotational speed and torque in the gas turbine engine; and control the electric motor so that the rotational speed of the fan approaches a required rotational speed during the execution of the engine torque control.

7. The hybrid aircraft propulsion system according to claim 5, wherein the processing circuit is configured to put the electric motor into a power generation state.

8. The hybrid aircraft propulsion system according to claim 1, further comprising: a clutch actuator for switching the clutch between a engaged state and a disengaged state; and a processing circuit for controlling the gas turbine engine, the electric motor, and the clutch actuator, wherein the processing circuit is configured to control the clutch actuator to disengage the clutch, and then control the gas turbine engine to drive the electric motor with the driving force of the engine's rotating shaft to generate electricity in the electric motor.

9. A hybrid aircraft propulsion system according to any one of claims 1 to 8, further comprising: a fuel tank for storing hydrogen fuel; and a fuel cell for generating electricity using hydrogen fuel from the fuel tank and extracted air from the compressor of the gas turbine engine.

10. The hybrid aircraft propulsion system according to claim 9, further comprising: a battery; an inverter for supplying power from the battery and the fuel cell to the electric motor; and a processing circuit for controlling the inverter, wherein the processing circuit is configured to control the inverter to increase the ratio of the current output from the battery to the current output from the fuel cell when the torque required for the electric motor satisfies a predetermined increase condition.

Images