Rotary-wing aircraft

Abstract

This specification provides a rotary-wing machine capable of adjusting the airflow rate directed to a component according to the temperature of the fuel cell stack. [Solution] The rotorcraft disclosed herein comprises a rotor that generates lift, a fuel cell stack, a duct that guides the airflow generated by the rotor to the fuel cell stack, a control valve that adjusts the flow rate of air passing through the duct, and a controller that controls the opening degree of the control valve according to the temperature of the fuel cell stack. Since the rotorcraft disclosed herein can adjust the flow rate of air passing through the duct, the amount of air sent to the fuel cell stack can be reduced when the rotor rotation speed is high or when the temperature of the fuel cell stack is low.

Description

Technical Field

[0001] The technology disclosed in this specification relates to rotary-wing aircraft. The rotary-wing aircraft in this specification includes so-called drones that fly unmanned, in addition to manned flying bodies such as helicopters and autogyros.

Background Art

[0002] Patent Documents 1 and 2 disclose rotary-wing aircraft equipped with fuel cells. The fuel cell is housed in the main body of the rotary-wing aircraft. In the rotary-wing aircraft of Patent Document 1, the main body is provided with an air inlet for guiding the airflow generated by the rotor to the fuel cell. The off-gas is diluted by the airflow passing through the fuel cell and discharged outside the main body.

[0003] The rotary-wing aircraft of Patent Document 2 includes a fuel discharge pipe for guiding the surplus fuel gas of the fuel cell toward the airflow of the rotor. In the rotary-wing aircraft of Patent Document 2, the surplus fuel gas can be efficiently discharged outside the main body.

[0004] Patent Document 3 discloses a rotary-wing aircraft that drives a rotor with an engine. This rotary-wing aircraft includes a duct for guiding the airflow of the rotor to the engine. Patent Document 4 discloses a rotary-wing aircraft in which the frame supporting the rotor is hollow, and the airflow of the rotor passes through the inside of the frame to cool electrical components.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Patent Document 2

Patent Document 3

Patent Document 4

[0006] The rotorcraft described in Patent Documents 1-4 all utilize the airflow generated by the rotor to cool the components. However, in all of these rotorcraft, the amount of air directed to the components is determined solely by the rotor speed, regardless of the component's temperature. This specification provides a rotorcraft that can adjust the amount of air directed from the rotor to the components according to the temperature of the components (fuel cell stack). [Means for solving the problem]

[0007] The rotorcraft disclosed herein comprises a rotor that generates lift, a fuel cell stack, a duct that guides the airflow generated by the rotor to the fuel cell stack, a control valve that adjusts the flow rate of air through the duct, and a controller that controls the opening of the control valve according to the temperature of the fuel cell stack. In the rotorcraft disclosed herein, the flow rate of air through the duct can be adjusted by the control valve, so even when the rotor rotation speed is high, the amount of air supplied to the fuel cell stack can be reduced when the temperature of the fuel cell stack is low.

[0008] The rotary-wing aircraft disclosed herein may further include a cooler for cooling the air passing through the duct. If the airflow rate through the duct alone is insufficient to cool the fuel cell stack, the cooler can be used to cool the air and effectively cool the fuel cell stack.

[0009] Details of the technology disclosed herein and further improvements are described in the following "Modes for Carrying Out the Invention". [Brief explanation of the drawing]

[0010] [Figure 1] This is a plan view of the rotary-wing machine of the embodiment. [Figure 2] This is a side view of a rotary-wing aircraft. [Figure 3] This is a cross-sectional view of a rotary-wing aircraft along the line III-III in Figure 1. [Figure 4]This is a flowchart for temperature control of a fuel cell stack. [Modes for carrying out the invention]

[0011] The rotary-wing aircraft 10 of the embodiment will be described with reference to the drawings. Figure 1 is a plan view of the rotary-wing aircraft 10, and Figure 2 is a side view of the rotary-wing aircraft 10. The X and Y axes of the coordinate system in the figures represent the front-rear and rear-lateral directions of the rotary-wing aircraft 10, respectively. The +Z direction represents the vertically upward direction.

[0012] The rotary-wing aircraft 10 is a so-called drone that flies by remote control. The rotary-wing aircraft 10 consists of a body 11, four rotors 12, four motors 13, a duct 15, a fuel cell stack 17, and a controller 19. For the sake of explanation, the "fuel cell stack" will be referred to as the "FC stack" below. The FC stack 17 is equipped with a temperature sensor 18 that measures its temperature.

[0013] The rotary-wing aircraft 10 flies by generating lift with four rotors 12. Each of the four rotors 12 is positioned at one of the four corners of the main body 11. A motor 13 drives the rotors 12. The motor 13 is driven by electricity generated by the fuel cell stack 17. The fuel cell stack 17 is located in the internal space 16 of the main body 11. In addition to the fuel cell stack 17, the main body 11 also contains devices necessary for power generation and a converter that converts the electricity from the fuel cell stack 17 into electricity suitable for driving the motors 13, but their illustrations and explanations are omitted.

[0014] Legs 14 extend downward from the four corners of the main body 11. The legs 14 are not shown in Figure 1.

[0015] One end of the duct 15 opens upward below one rotor 12, and the other end opens into the internal space 16. The duct 15 receives the downward airflow generated by the rotor 12 and guides that airflow to the FC stack 17. The FC stack 17 generates heat during power generation. The air guided by the duct 15 cools the FC stack 17.

[0016] Note that the main body 11 is provided with an exhaust duct 22 having one end opening into the internal space 16 and the other end opening at the bottom of the main body 11. The air after cooling the FC stack 17 is exhausted to the outside of the main body 11 through the exhaust duct 22.

[0017] Fig. 3 shows a cross-sectional view of the rotary wing machine 10 along the line III-III of Fig. 1. In Fig. 3, a part of the rotary wing machine 10 is omitted from illustration. Also in Fig. 3, illustrations of devices housed in the main body 11 are omitted except for the controller 19, the FC stack 17, and the temperature sensor 18.

[0018] As described above, one end of the duct 15 opens below the rotor 12 and the other end opens into the internal space 16. An adjustment valve 20 and a Peltier element 21 are arranged inside the duct 15. The adjustment valve 20 adjusts the flow rate of the air passing through the duct 15. The adjustment valve 20 drawn in solid line in Fig. 3 shows a substantially fully open state, and the adjustment valve 20a drawn in two-dot chain line shows a fully closed state. The adjustment valve 20 can be opened and closed by a motor (not shown), and the controller 19 adjusts the opening degree of the adjustment valve 20.

[0019] Also, the Peltier element 21 is an element whose temperature drops when energized, and the air passing through the duct 15 is cooled by the Peltier element 21. The Peltier element 21 is a cooler that cools the air passing through the duct 15. The Peltier element 21 is also controlled by the controller 19.

[0020] The controller 19 controls the adjustment valve 20 and the Peltier element 21 based on the temperature of the FC stack 17 measured by the temperature sensor 18. The controller 19 controls the adjustment valve 20 and the Peltier element 21 so that the temperature of the FC stack 17 is maintained within an appropriate range.

[0021] FIG. 4 shows a flowchart of the temperature adjustment control of the FC stack 17. As described above, the temperature of the FC stack 17 is measured by the temperature sensor 18. The controller 19 stores the appropriate temperature range of the FC stack 17. The controller 19 compares the temperature of the FC stack 17 with the appropriate temperature range (step S2). If the temperature of the FC stack 17 is within the appropriate range, the controller 19 does nothing to the control valve 20 and the Peltier element 21.

[0022] If the temperature of the FC stack 17 is lower than the appropriate range, the controller 19 closes the control valve 20 by a predetermined angle if the control valve 20 is not fully closed (steps S3: NO, S4). Closing the control valve 20 by a predetermined angle reduces the flow rate in the duct 15. As a result, the amount of air guided to the FC stack 17 in the airflow generated by the rotor 12 decreases, and the temperature of the FC stack 17 tends to rise. If the control valve 20 is fully closed (step S3: YES), the controller 19 does nothing.

[0023] If the temperature of the FC stack 17 is higher than the appropriate range, the controller 19 opens the control valve 20 by a predetermined angle if the control valve 20 is not fully open (steps S5: NO, S6). Opening the control valve 20 by a predetermined angle increases the flow rate in the duct 15. As a result, the amount of air guided to the FC stack 17 in the airflow generated by the rotor 12 increases, and the FC stack 17 is cooled.

[0024] If the control valve 20 is fully open, the controller 19 energizes the Peltier element 21 (steps S5: YES, S7). As described above, when the Peltier element 21 is energized, the temperature of the Peltier element 21 drops, and the air passing through the duct 15 is cooled. As a result, the FC stack 17 is cooled.

[0025] The controller 19 repeats the above process until the rotary wing machine 10 stops (steps S8: NO, S2).

[0026] As described above, the rotary-wing aircraft 10 controls the control valve 20 according to the temperature of the FC stack 17, thereby changing the flow rate of the duct 15. If the temperature of the FC stack 17 is low, the control valve 20 is closed to reduce the flow rate of the duct 15. If the temperature of the FC stack 17 is high, the control valve 20 is opened to increase the flow rate of the duct 15. If the temperature of the FC stack 17 is high even when the control valve 20 is fully open, the controller 19 energizes the Peltier element 21 to lower the temperature of the Peltier element 21. As a result, the air passing through the duct 15 is cooled, and cool air is sent to the FC stack 17.

[0027] Points to note regarding the technology described in the examples are stated below. The rotorcraft 10 in the examples has a plurality of rotors 12 and a single duct 15 that opens directly below one rotor 12. The rotorcraft disclosed herein may have a plurality of ducts, each opening directly below a rotor.

[0028] In the rotary-wing aircraft 10 of this embodiment, a Peltier element is used to cool the air inside the duct 15. Other devices besides a Peltier element may be used as a cooler for cooling the air.

[0029] The technology disclosed herein is applicable not only to drones but also to manned helicopters and gyrocopters. In the rotary-wing aircraft 10 of the embodiment, the FC stack 17, which is cooled by the airflow of the rotor, supplies power to the motor 13 for the rotor. The technology disclosed herein may also be a rotary-wing aircraft in which the rotor is driven by an engine, and the FC stack 17 supplies power to devices other than the rotor.

[0030] Although specific examples of the present invention have been described in detail above, these are merely illustrative and do not limit the scope of the claims. The technologies described in the claims include various modifications and changes to the specific examples illustrated above. The technical elements described in this specification or drawings exhibit technical usefulness individually or in various combinations, and are not limited to the combinations described in the claims at the time of filing. Furthermore, the technologies illustrated in this specification or drawings can achieve multiple objectives simultaneously, and achieving even one of these objectives itself constitutes technical usefulness. [Explanation of Symbols]

[0031] 10: Rotary-wing aircraft 11: Main body 12: Rotor 13: Motor 14: Landing gear 15: Duct 17: Fuel cell stack 18: Temperature sensor 19: Controller 20: Control valve 21: Peltier element 22: Exhaust duct

Claims

1. A rotor that generates lift, Fuel cell stack and A duct that guides the airflow generated by the rotor to the fuel cell stack, A control valve for changing the airflow rate through the duct, A controller that controls the opening degree of the control valve according to the temperature of the fuel cell stack, A rotary-wing aircraft equipped with this feature.

2. The rotary-wing aircraft according to claim 1, further comprising a cooler for cooling the air passing through the duct.

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