Control device for electric aircraft and method for controlling electric aircraft

Abstract

To provide a control device for an electric aircraft that can suppress noise and an exhaust gas emitted from an internal combustion engine at the time of takeoff.SOLUTION: A control device 6 controls an electric aircraft 100 that includes: a motor 2 for driving a rotor 1; a storage battery 3 for supplying power to the motor 2; a power generator 4 using an internal combustion engine 5 as a power source and capable of supplying power to the motor 2 and the storage battery 3; and an altitude acquisition device 7 for acquiring a flight altitude. The control device 6 supplies power to the motor 2 from the storage battery 3 while stopping the internal combustion engine 5 to cause the electric aircraft 100 to take off, after the takeoff of the electric aircraft 100, determines whether an altitude H of the electric aircraft 100 is equal to or higher than an altitude threshold Ht, and when the altitude H of the electric aircraft 100 acquired by the altitude acquisition device 7 is equal to or more than the altitude threshold Ht, activates the internal combustion engine 5.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to a control device for an electric aircraft and a control method for an electric aircraft. [Background technology]

[0002] In order to extend flight time, electric aircraft have been developed that are equipped with a generator powered by an internal combustion engine in addition to batteries. Patent Document 1 discloses a system for this electric aircraft that controls the internal combustion engine (gas turbine internal combustion engine) based on the amount of electricity stored in the battery to make the generator generate electricity. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2019-077361 A Summary of the Invention [Problem to be solved by the invention]

[0004] In the control system for an electric aircraft in Patent Document 1, not only does the internal combustion engine output at maximum power to cause the generator to generate electricity when the aircraft takes off, but the propeller is driven using electricity stored in a battery, making it possible to downsize the internal combustion engine (gas turbine internal combustion engine). However, noise and exhaust gases are generated from the internal combustion engine during takeoff, making it difficult to use it in urban areas or places close to residential environments.

[0005] An object of the present invention is to provide a control device for an electric aircraft that can suppress noise and exhaust gases generated from an internal combustion engine during takeoff. [Means for solving the problem]

[0006] The present application includes multiple means for solving the above problems, and one example is a control device for controlling an electric aircraft including a motor that drives a rotor, a storage battery that supplies power to the motor, a generator that is powered by an internal combustion engine and can supply power to the motor and the storage battery, and an altitude acquisition device that acquires flight altitude, wherein the control device supplies power from the storage battery to the motor while the internal combustion engine is stopped to cause the electric aircraft to take off, and after the electric aircraft takes off, determines whether the altitude of the electric aircraft acquired by the altitude acquisition device is equal to or greater than an altitude threshold, and if the altitude of the electric aircraft is equal to or greater than the altitude threshold, starts the internal combustion engine. Effect of the Invention

[0007] According to the present invention, since the noise and exhaust gas generated from the internal combustion engine during takeoff can be suppressed, the aircraft can be used in urban areas and places close to human habitation. Problems, configurations and effects other than those described above will become apparent from the following description of the embodiments. [Brief description of the drawings]

[0008] [Figure 1] 1 is a schematic configuration diagram of an electric aircraft according to a first embodiment of the present invention. [Diagram 2] 1 is a block diagram showing an example of a hardware configuration of a control device according to a first embodiment of the present invention, a device for inputting data to the control device, and a device for outputting command data from the control device. [Diagram 3] FIG. 2 is a diagram showing an example of a flowchart executed at takeoff by the control device according to the first embodiment of the present invention. [Figure 4] FIG. 2 is a diagram showing an example of a flowchart executed by the control device according to the first embodiment of the present invention at the time of landing. [Diagram 5] FIG. 1 is a schematic configuration diagram of an electric aircraft according to a second embodiment of the present invention. [Figure 6] FIG. 11 is a block diagram showing an example of a hardware configuration of a control device according to a second embodiment of the present invention, a device for inputting data to the control device, and a device for outputting command data from the control device. [Figure 7] 1 is a graph showing the remaining battery charge in a charger and the altitude of an electric aircraft when the electric aircraft takes off and ascends using only the remaining battery charge. [Figure 8] 4 is a graph showing a relationship between the cooling water temperature of an internal combustion engine and the rate of change of combustion at startup. [Figure 9] 1 is a graph showing the relationship between the ambient air temperature of an electric aircraft and the rate of change of combustion at startup. [Figure 10] 1 is a graph showing the relationship between the ambient air pressure of an electric aircraft and the rate of change of combustion at startup. [Figure 11] FIG. 11 is a diagram showing an example of a flowchart executed at takeoff by a control device according to a second embodiment of the present invention. [Figure 12] FIG. 11 is a diagram showing an example of a flowchart executed by a control device according to a second embodiment of the present invention at the time of landing. [Figure 13] 4 is a graph showing the relationship between fuel temperature and combustion variation rate at startup of an internal combustion engine. [Figure 14] 1 is a graph showing the relationship between the humidity around an electric aircraft and the fuel temperature threshold of an internal combustion engine. [Figure 15] 1 is a graph showing the relationship between ethanol content in a fuel and a fuel temperature threshold value. [Figure 16] 6 is an example of a time chart showing a state of an electric aircraft according to a second embodiment of the present invention from takeoff to landing at a destination. [Figure 17] FIG. 11 is a schematic configuration diagram of an electric aircraft according to a third embodiment of the present invention. [Figure 18] FIG. 11 is a block diagram showing an example of a hardware configuration of a control device according to a third embodiment of the present invention, a device for inputting data to the control device, and a device for outputting command data from the control device. [Figure 19] FIG. 11 is a diagram showing an example of a flowchart executed at takeoff by a control device according to a third embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] The configuration and operation of the control device for an electric aircraft according to the first to third embodiments of the present invention will be described below with reference to the drawings. Note that the same reference numerals denote the same parts in each drawing.

[0010] (First embodiment) FIG. 1 is a schematic configuration diagram of an electric aircraft according to a first embodiment of the present invention.

[0011] The electric aircraft 100 of this embodiment is, for example, an electric vertical take-off and landing aircraft (eVTOL), and is equipped with a rotor 1, a motor 2, a storage battery 3, a generator 4, an internal combustion engine 5, a control device 6, and an altitude acquisition device 7.

[0012] The rotor 1 is a device that generates lift for the electric aircraft 100. The electric aircraft 100 of this embodiment is provided with four rotors 1.

[0013] The motors 2 are devices that drive the rotors 1. In the electric aircraft 100 of this embodiment, the four motors 2 are mechanically connected to the four rotors 1, respectively.

[0014] The storage battery 3 is a device that supplies power to the motor 2 via a power converter, and preferably has a capacity equal to or greater than the output required for the electric aircraft 100 to take off.

[0015] The generator 4 is a device that uses an internal combustion engine 5 as a power source and can supply electric power to the motor 2 and the storage battery 3 via a power converter.

[0016] The internal combustion engine 5 is a device that is mechanically connected to the generator 4 to drive the generator 4 to generate electricity, for example a reciprocating engine, and can use gasoline, diesel, gas, etc. as fuel.

[0017] The control device 6 is a powertrain control device that controls the powertrain (power transmission system), supplies power from the storage battery 3 to the motor 2 while keeping the internal combustion engine 5 stopped, causes the electric aircraft 100 to take off, and after the electric aircraft 100 takes off, determines whether the altitude H of the electric aircraft 200 acquired by the altitude acquisition device 7 is equal to or greater than an altitude threshold Ht, and starts the internal combustion engine 5 if the altitude H of the electric aircraft 200 is equal to or greater than the altitude threshold Ht. The altitude threshold Ht is the minimum altitude (e.g., 500 feet (approximately 152 meters)) that should be maintained above urban areas as specified by guidelines, etc.

[0018] The altitude acquisition device 7 is a device that acquires the flight altitude of the electric aircraft 100, and specifically, for example, is a pressure altitude sensor that detects altitude by pressure or a radio wave altitude sensor that detects altitude by radio waves. Since the altitude acquisition device 7 is a device that can acquire the flight altitude of the electric aircraft 100, for example, a device that calculates the altitude of the electric aircraft 200 based on positioning signals received from a plurality of positioning satellites, for example, a GPS (Global Positioning System) receiver, can also be used. The control device 6 determines whether the altitude H of the electric aircraft 200 acquired by the altitude acquisition device 7 is equal to or greater than the altitude threshold Ht. The control device 6 may also determine whether the electric aircraft 100 has taken off based on the altitude H of the electric aircraft 200 acquired by the altitude acquisition device 7. An altimeter (a pressure altimeter or a radio wave altimeter) can also be used for the altitude acquisition device 7. In this case, an operator, instead of the control device 6, may determine whether the altitude H of the electric aircraft 200 is equal to or greater than the altitude threshold Ht or whether the electric aircraft 100 has taken off based on the measurement value of the altimeter.

[0019] 2 is a block diagram showing an example of a hardware configuration of the control device 6 according to this embodiment, a device that inputs data to the control device 6, and a device that outputs command data from the control device 6. The control device 6 is formed of an electronic computer.

[0020] As shown in FIG. 2, the control device 6 includes an input / output circuit 6a, a first storage device 6b, a calculation device 6c, and a second storage device 6d.

[0021] The input / output circuit 6a is a device that receives signals and data from the outside and transmits internal information and results to the outside. The altitude H of the electric aircraft 100 acquired by the altitude acquisition device 7 is input to the input / output circuit 6a. The data of the altitude H of the electric aircraft 100 input to the input / output circuit 6a is sent to the first storage device 6b and stored therein.

[0022] The first storage device 6b is a device that temporarily stores data, such as a random access memory (RAM). The data of the altitude H of the electric aircraft 100 temporarily stored in the first storage device 6b is read by the calculation device 6c.

[0023] The arithmetic device 6c is a device, such as a CPU (Central Processing Unit), that calculates whether or not to start the internal combustion engine 5 from the altitude data of the electric aircraft 100. The arithmetic device 6c reads a program and the altitude threshold value Ht from the second storage device 6d, calculates whether or not to start the internal combustion engine 5 based on the data of the altitude H of the electric aircraft 100 input from the first storage device 6b, and outputs command data for the storage battery 3 and the internal combustion engine 5.

[0024] The second storage device 6d is a device that stores the program and the altitude threshold value Ht, for example, a ROM (Read-Only Memory). The program and the altitude threshold value Ht are stored in advance in the second storage device 6d.

[0025] Command data for the controlled objects (the storage battery 3 and the internal combustion engine 5) calculated by the calculation device 6c according to the control program is stored in the first memory device 6b and then sent to the controlled objects (the storage battery 3 and the internal combustion engine 5) via the input / output circuit 6a.

[0026] Fig. 3 is a diagram showing an example of a flowchart executed by the control device 6 according to the present embodiment at the time of takeoff. Fig. 4 is a diagram showing an example of a flowchart executed by the control device 6 according to the present embodiment at the time of landing.

[0027] The control device 6 controls the start and stop of the internal combustion engine 5 based on the data of the altitude H acquired by the altitude acquisition device 7. Specifically, the control device 6 executes the process shown in Fig. 3 at the time of takeoff, and executes the process shown in Fig. 4 at the time of landing.

[0028] 3 is started when the operator starts operation of the electric aircraft 100, and in a takeoff step 1, the control device 6 supplies power from the storage battery 3 to the motor 2 to drive the rotor 1. The control device 6 also maintains the internal combustion engine 5 in a stopped state.

[0029] Next, the control device 6 determines whether the electric aircraft 100 has taken off in a takeoff step 2. Note that the altitude H acquired by the altitude acquisition device 7 can be used to determine whether the electric aircraft 100 has taken off.

[0030] If it is determined that the electric aircraft 100 has taken off (YES), the process proceeds to takeoff step 3. If it is determined that the electric aircraft 100 has not taken off (NO), the process returns to takeoff step 1.

[0031] Next, in the takeoff step 3, the control device 6 determines whether the altitude H of the electric aircraft 100 is equal to or greater than the altitude threshold Ht. As described above, the altitude threshold Ht is the minimum altitude (e.g., 500 feet (approximately 152 meters)) that should be maintained above urban areas as stipulated by guidelines, etc. The altitude H acquired by the altitude acquisition device 7 is used to determine whether the electric aircraft 100 is equal to or greater than the altitude threshold Ht.

[0032] If the altitude H of the electric aircraft 100 is less than the altitude threshold Ht (NO), the process returns to takeoff step 3. If the altitude H of the electric aircraft 100 is equal to or greater than the altitude threshold Ht (YES), in takeoff step 4, the control device 6 starts the internal combustion engine 5 and ends the takeoff process.

[0033] Next, when the electric aircraft 100 approaches the destination, the control device 6 executes the landing process shown in FIG.

[0034] First, when the operator operates to start landing the electric aircraft 100, the flow executed by the control device 6 during landing in Fig. 4 is started, and in landing step 1, the control device 6 determines whether the altitude H of the electric aircraft 100 acquired by the altitude acquisition device 7 is less than the altitude threshold Ht. If the altitude H is equal to or greater than the altitude threshold Ht (NO), the process returns to landing step 1. If the altitude H is less than the altitude threshold Ht (YES), the process proceeds to landing step 2, where the control device 6 stops the internal combustion engine 5, and the process proceeds to landing step 3.

[0035] Next, in a landing step 3, the control device 6 drives the motor 2 using only the power supplied from the storage battery 3 to land the electric aircraft 100, and ends the processing at the time of landing.

[0036] [effect] The control device 6 of this embodiment supplies power from the storage battery 3 to the motor 2 while stopping the internal combustion engine 5 to cause the electric aircraft 100 to take off, and after the electric aircraft 100 takes off, determines whether the altitude of the electric aircraft 100 acquired by the altitude acquisition device 7 is equal to or greater than the altitude threshold Ht, and starts the internal combustion engine 5 if the altitude H of the electric aircraft 100 is equal to or greater than the altitude threshold Ht. Therefore, the electric aircraft 100 of this embodiment stops the internal combustion engine 5 after takeoff until the altitude H becomes equal to or greater than the altitude threshold Ht, and can take off from urban areas or locations close to human habitations because noise and exhaust gas generated by the internal combustion engine 5 can be suppressed.

[0037] Furthermore, when approaching a destination and landing, the control device 6 of this embodiment preferably stops the internal combustion engine 5 when the altitude H of the electric aircraft 100 acquired by the altitude acquisition device 7 falls below the altitude threshold Ht, and lands the electric aircraft 100 by driving the motor 2 only with power supplied from the storage battery 3. As a result, the electric aircraft 100 of this embodiment stops the internal combustion engine 5 until the altitude threshold Ht is passed and the aircraft 100 lands, thereby suppressing noise and exhaust gas generated by the internal combustion engine 5, and therefore allowing the aircraft 100 to land in urban areas or places close to residential areas.

[0038] Furthermore, the control device 6 may determine that the electric aircraft 100 has taken off based on the altitude H of the electric aircraft 100 acquired by the altitude acquisition device 7. This makes it possible to easily determine that the electric aircraft 100 has taken off. Furthermore, since an altimeter (pressure altimeter or radio altimeter) that measures the altitude of the aircraft is usually attached to an aircraft, this can be used as the altitude acquisition device 7 to acquire the altitude H of the electric aircraft 200 and determine whether the altitude H is equal to or greater than the altitude threshold Ht or whether the electric aircraft 100 has taken off, thereby reducing costs.

[0039] Furthermore, the control method for controlling the electric aircraft 100 of this embodiment is characterized in that the electric aircraft 100 takes off by supplying power from the storage battery 3 to the motor 2 while keeping the internal combustion engine 5 stopped, and after the electric aircraft 100 takes off, it is determined whether the altitude H of the electric aircraft 100 acquired by the altitude acquisition device 7 is equal to or greater than the altitude threshold Ht, and if the altitude H of the electric aircraft 100 is equal to or greater than the altitude threshold Ht, the internal combustion engine 5 is started. Therefore, the control method for controlling the electric aircraft 100 of this embodiment stops the internal combustion engine 5 after takeoff until the altitude H becomes equal to or greater than the altitude threshold Ht, and noise and exhaust gas generated by the internal combustion engine 5 can be suppressed, allowing the electric aircraft to take off from urban areas or locations close to human living environments.

[0040] Second embodiment 5 is a schematic configuration diagram of an electric aircraft 200 according to a second embodiment of the present invention. The electric aircraft 200 according to this embodiment differs from the electric aircraft 100 according to the first embodiment in that it includes a battery remaining amount sensor 203, a water temperature sensor 205, an environmental sensor 208, a position receiver 209 having the function of the altitude acquisition device 7, a start confirmation sensor 210, and a start auxiliary device 211.

[0041] The battery remaining amount sensor 203 is one of a plurality of start condition sensors that detect the start condition of the internal combustion engine 5, and detects the remaining amount of the battery in the storage battery 3.

[0042] The water temperature sensor 205 is one of a plurality of start condition sensors that detect the start condition of the internal combustion engine 5, and detects the temperature of the cooling water for the internal combustion engine 5.

[0043] The environmental sensor 208 is a sensor that detects physical quantities such as the temperature and air pressure around the electric aircraft 100. In this embodiment, the environmental sensor 208 is provided, but instead of the environmental sensor 208, an air temperature sensor that detects the air temperature around the electric aircraft 100, an air pressure sensor that detects the air pressure around the electric aircraft 100, and a humidity sensor that detects the humidity around the electric aircraft 100 may be provided.

[0044] The position receiver 9 is a device that calculates the position and altitude of the electric aircraft 200 based on positioning signals received from multiple positioning satellites, for example, a GPS (Global Positioning System) receiver, and detects, for example, the distance D between the electric aircraft 100 and an urban area and the altitude H of the electric aircraft 200. Therefore, the position receiver 9 has the function of the altitude acquisition device 7.

[0045] The start confirmation sensor 210 is a sensor that confirms the start of the internal combustion engine 5, and is, for example, a crank angle sensor.

[0046] The starting assistance device 211 is a device that assists in the starting of the internal combustion engine 5 and has at least one of the following functions: increasing the amount of fuel injected into the engine, thereby increasing the fuel concentration of the fuel-air mixture mixed in the engine, and increasing the ignition energy, which is the energy required for ignition by the spark plug.

[0047] FIG. 6 is a block diagram showing an example of the hardware configuration of the control device 206 according to this embodiment, a device that inputs data to the control device 206, and a device to which command data is output from the control device 206.

[0048] The control device 206 according to this embodiment differs from the control device 6 according to the first embodiment in the following respects. That is, the devices that input data to the control device 206 are the battery remaining amount sensor 203, the water temperature sensor 205, the environment sensor 208, the position receiver 209 having the function of the altitude acquisition device 7, and the start confirmation sensor 210. Also, in addition to the altitude threshold value Ht, other threshold values ​​described below are stored in the second storage device 206d. Also, a start auxiliary device 211 is added to the devices to which command data is output from the control device 206. As described above, the environment sensor 8 may be replaced with an air temperature sensor that detects the air temperature around the electric aircraft 100, an air pressure sensor that detects the air pressure around the electric aircraft 100, and a humidity sensor that detects the humidity around the electric aircraft 100.

[0049] Specifically, the data input from the battery remaining amount sensor 203 to the control device 206 is the remaining battery amount (SOC: State of Charge) of the storage battery 3. In addition, the data input from the water temperature sensor 205 to the control device 206 is the coolant temperature Tw of the internal combustion engine 5.

[0050] The data input from the environmental sensor 208 to the control device 206 is physical quantities around the electric aircraft 100, such as the air temperature Ta and the air pressure Pa. The air temperature Ta may be a value detected by an air temperature sensor, and the air pressure Pa may be a value detected by an air pressure sensor. As described above, the data input from the position receiver 209 to the control device 206 is, for example, the distance D between the electric aircraft 200 and the urban area and the altitude H of the electric aircraft 200.

[0051] In addition, the second memory device 206d stores, for example, a takeoff SOCt, which is the remaining battery charge required in the storage battery 3 for the electric aircraft 200 to take off, a water temperature threshold Twt, which is the threshold for the cooling water temperature Tw of the internal combustion engine 5, and an air temperature threshold Tat and an air pressure threshold Pat, which are respective thresholds for the air temperature Ta and air pressure Pa surrounding the electric aircraft 100.

[0052] FIG. 7 is a graph showing the remaining battery charge SOC of the storage battery 3 and the altitude H of the electric aircraft 200 when the electric aircraft 200 takes off and ascends based only on the remaining battery charge SOC.

[0053] As shown in FIG. 7, the takeoff SOCt is the remaining battery charge SOC required for the electric aircraft 200 to take off and ascend to an altitude threshold Ht, which is the minimum altitude that should be maintained above a city.

[0054] Fig. 8 is a graph showing the relationship between the coolant temperature Tw of the internal combustion engine 5 and the rate of variation of combustion at startup. Fig. 9 is a graph showing the relationship between the air temperature Ta around the electric aircraft 200 according to this embodiment and the rate of variation of combustion at startup. Fig. 10 is a graph showing the relationship between the air pressure Pa around the electric aircraft 200 according to this embodiment and the rate of variation of combustion at startup.

[0055] The startup combustion fluctuation rate is an index that represents the degree of instability and fluctuation in combustion that occurs when the internal combustion engine 5 is started. The higher the startup combustion fluctuation rate, the more difficult it is to start the internal combustion engine 5, and the lower the startup combustion fluctuation rate, the easier it is to start the internal combustion engine 5.

[0056] As shown in Fig. 8, the water temperature threshold Twt is the coolant temperature Tw of the internal combustion engine 5 when the rate of variation in combustion at startup reaches the starting limit value of the internal combustion engine 5. Since the rate of variation in combustion at startup is smaller as the coolant temperature Tw of the internal combustion engine 5 is higher, the higher the coolant temperature Tw, the easier it is to start the internal combustion engine 5. On the other hand, as the coolant temperature Tw decreases, the rate of variation in combustion at startup increases, making it more difficult to start the internal combustion engine 5. On the other hand, as the electric aircraft 200 rises, the coolant temperature Tw decreases. Therefore, it is preferable that the control device 6 start the internal combustion engine 5 while the electric aircraft 200 rises and the coolant temperature Tw decreases, and the coolant temperature Tw becomes equal to or lower than the water temperature threshold Twt and the internal combustion engine 5 reaches the starting limit.

[0057] 9, the air temperature threshold Tat is the air temperature Ta around the electric aircraft 200 when the starting combustion variation rate reaches the starting limit value of the internal combustion engine 5. Since the starting combustion variation rate is smaller as the air temperature Ta around the electric aircraft 200 is higher, the higher the air temperature Ta is, the easier it is to start the internal combustion engine 5. On the other hand, as the air temperature Ta falls, the starting combustion variation rate increases, making it more difficult to start the internal combustion engine 5. On the other hand, as the electric aircraft 200 rises, the air temperature Ta falls. Therefore, it is preferable for the control device 6 to start the internal combustion engine 5 while the electric aircraft 200 rises and the air temperature Ta falls, so that the air temperature Ta becomes equal to or lower than the air temperature threshold Ta and the internal combustion engine 5 reaches its starting limit.

[0058] 10, the atmospheric pressure threshold Pat is the atmospheric pressure Pa around the electric aircraft 200 when the starting combustion variation rate reaches the starting limit of the internal combustion engine 5. Since the starting combustion variation rate is smaller as the atmospheric pressure Pa around the electric aircraft 200 is higher, the higher the atmospheric pressure Pa is, the easier it is to start the internal combustion engine 5. On the other hand, as the atmospheric pressure Pa decreases, the starting combustion variation rate increases, making it more difficult to start the internal combustion engine 5. On the other hand, as the electric aircraft 200 ascends, the atmospheric pressure Pa decreases. Therefore, it is preferable for the control device 6 to start the internal combustion engine 5 while the electric aircraft 200 ascends and the atmospheric pressure Pa decreases, so that the atmospheric pressure Pa becomes equal to or lower than the atmospheric pressure threshold Pat and the internal combustion engine 5 reaches its starting limit.

[0059] Fig. 11 is a diagram showing an example of a flowchart executed by the control device 206 according to this embodiment at the time of takeoff. Fig. 12 is a diagram showing an example of a flowchart executed by the control device 206 according to this embodiment at the time of landing.

[0060] The flow executed by the control device 206 at takeoff according to this embodiment differs from the flow executed by the control device 6 at takeoff according to the first embodiment in the following points.

[0061] First, it has a step of comparing the remaining battery charge SOC of the storage battery 3, the air temperature Ta and air pressure Pa detected by the environmental sensor 208, the coolant temperature Tw of the internal combustion engine 5, and the distance D from the urban area detected by the position receiver 209 with their respective threshold values.

[0062] Secondly, the method includes a step of checking whether the internal combustion engine 5 is started, and starting the internal combustion engine 5 using the starting aid 211 if the internal combustion engine 5 is not started.

[0063] In this embodiment, instead of the altitude acquisition device 7 that acquires the flight altitude, the position receiver 209 acquires the altitude H. In addition, the air temperature Ta may be detected by an air temperature sensor that detects the air temperature around the electric aircraft 200, and the air pressure Pa may be detected by an air pressure sensor that detects the air pressure around the electric aircraft 200.

[0064] The flow executed by the control device 206 according to this embodiment at the time of landing differs from the flow executed by the control device 6 according to the first embodiment at the time of landing in that the flow includes the following two steps.

[0065] One is a landing step 201 in which the remaining battery capacity SOC of the storage battery 3 is compared with a landing SOCt, which is the remaining battery capacity SOC required for the electric aircraft 200 to descend and land from an altitude threshold Ht, which is the minimum altitude that the electric aircraft 200 should maintain above a city area.

[0066] The other is a landing step 203 that compares the distance D from the city detected by the position receiver 209 with a distance threshold Dt.

[0067] Specifically, the control device 206 executes the processes shown in FIGS.

[0068] First, when the operator starts operation of the electric aircraft 200, the flow executed by the control device 206 at takeoff in Fig. 11 is started, and in a takeoff step 201, the control device 206 determines whether the remaining battery capacity SOC is equal to or greater than the takeoff SOCt based on the detected value of the remaining battery capacity SOC of the storage battery 3 by the battery capacity sensor 203. Note that the takeoff SOCt is the remaining battery capacity SOC required for the electric aircraft 200 to take off, ascend, and reach an altitude of the altitude threshold Ht as described above.

[0069] If the battery remaining SOC is equal to or greater than the takeoff SOCt (YES), in takeoff step 202, power is supplied from the storage battery 3 to the motor 2 to drive the rotor 1. If the battery remaining SOC is less than the takeoff SOCt (NO), the control device 206 does not supply power from the storage battery 3 to the motor 2 in order to charge the storage battery 3 from a power source (e.g., a ground commercial power source), turns off the power supply to the electric aircraft 200, and ends the flow.

[0070] Next, the control device 206 determines whether or not the electric aircraft 200 has taken off in a takeoff step 203. Whether or not the electric aircraft 200 has taken off can be determined based on the altitude H acquired by the position receiver 209.

[0071] If it is determined that the electric aircraft 200 has taken off (YES), the process proceeds to the takeoff step 204. If it is determined that the electric aircraft 200 has not taken off (NO), the process returns to the takeoff step 201.

[0072] Next, in the takeoff step 204, the control device 206 determines whether the battery remaining charge SOC is equal to or lower than the lower threshold Lt, the cooling water temperature Tw is equal to or lower than the water temperature threshold Twt, the air temperature Ta is equal to or lower than the air temperature threshold Tat, and the air pressure Pa is equal to or lower than the air pressure threshold Pat. The lower threshold Lt is the minimum charge amount required for the storage battery 3.

[0073] If the battery remaining charge SOC is equal to or lower than the lower threshold Lt, the cooling water temperature Tw is equal to or lower than the water temperature threshold Twt, the air temperature Ta is equal to or lower than the air temperature threshold Tat, or the air pressure Pa is equal to or lower than the air pressure threshold Pat (YES), there is a risk that the internal combustion engine 5 will not start, so in takeoff step 205, the control device 206 transmits command data to start the internal combustion engine 5 and proceeds to takeoff step 206.

[0074] If the battery remaining charge SOC is not equal to or lower than the lower limit threshold Lt, the cooling water temperature Tw is not equal to or lower than the water temperature threshold Twt, the air temperature Ta is not equal to or lower than the air temperature threshold Tat, and the air pressure Pa is not equal to or lower than the air pressure threshold Pat (NO), the process proceeds to takeoff step 207.

[0075] In the above, an example has been shown in which the control device 206 makes a determination in the takeoff step 204 based on the remaining battery charge SOC of the storage battery 3, the coolant temperature Tw of the internal combustion engine 5, and the air temperature Ta and air pressure Pa around the electric aircraft 200. However, the present invention is not limited to these.

[0076] For example, the control device 206 may determine whether the humidity detected by the environmental sensor 208 or the humidity sensor is equal to or greater than a humidity threshold value. This is because, when the humidity around the electric aircraft 200 becomes high, it becomes difficult to start the internal combustion engine 5 for the following reason.

[0077] First, a proper air-fuel ratio (ratio of air to fuel) is necessary for proper combustion in the internal combustion engine 5. However, when humidity is high, the oxygen concentration in the air decreases, and more air is required to burn the same amount of fuel. Therefore, when humidity is high, there is a risk that sufficient air will not be supplied and it will become difficult to start the internal combustion engine 5.

[0078] Secondly, in high humidity conditions, moisture can affect the engine's spark plugs, wiring, etc. Moisture on the spark plugs can make ignition difficult or unreliable, which can make it difficult to start the internal combustion engine 5.

[0079] Thirdly, high humidity can hinder the evaporation of fuel. If the fuel is supplied to the combustion chamber as a liquid rather than evaporating into a mist, a homogeneous mixture cannot be obtained, which can cause problems with combustion and may make it difficult to start the internal combustion engine 5.

[0080] Furthermore, in the case of rainy weather, the humidity is high, so the weather may be added to the conditions for determining whether or not to perform the takeoff step 204 .

[0081] FIG. 13 is a graph showing the relationship between the fuel temperature Tf of the internal combustion engine 5 and the combustion variation rate at startup.

[0082] A fuel temperature sensor that detects a fuel temperature Tf of the internal combustion engine 5 may be used as one of the multiple start condition sensors that detect the start condition of the internal combustion engine 5. In the takeoff step 204, the control device 206 may determine whether the fuel temperature Tf detected by the fuel temperature sensor is equal to or lower than a fuel temperature threshold value Tft shown in FIG.

[0083] The fuel temperature threshold value Tft is the fuel temperature Tf of the internal combustion engine 5 when the combustion variation rate at start-up reaches the start limit value of the internal combustion engine 5, as shown in FIG.

[0084] In the takeoff step 204, the reason for determining whether the fuel temperature Tf detected by the fuel temperature sensor is equal to or lower than the fuel temperature threshold value Tft is that if the fuel temperature Tf of the internal combustion engine 5 becomes low, the vaporizability of the fuel decreases, and the fuel is supplied to the combustion chamber as a liquid without being vaporized, so that an appropriate mixture cannot be obtained, ignition and combustion become difficult, and there is a risk that it may become difficult to start the internal combustion engine 5.

[0085] Fig. 14 is a graph showing the relationship between the humidity around the electric aircraft 200 and the fuel temperature threshold value Tft of the internal combustion engine 5. As described above, high humidity reduces the oxygen concentration in the air and inhibits fuel evaporation, making it difficult to start the internal combustion engine 5. Therefore, the higher the humidity around the electric aircraft 200, the more difficult it becomes to start the internal combustion engine 5, so as shown in Fig. 14, the fuel temperature threshold value Tft may be increased as the humidity around the electric aircraft 200 increases.

[0086] In addition, it is preferable to vary the fuel temperature threshold value Tft depending on the type of fuel. For example, when comparing gasoline and bioethanol, bioethanol is more difficult to vaporize and is therefore more difficult to start the internal combustion engine 5. Therefore, it is preferable to set the fuel temperature threshold value Tft for bioethanol higher than that for gasoline.

[0087] Fig. 15 is a graph showing the relationship between the ethanol content in fuel and the fuel temperature threshold value Tft. The higher the ethanol content in the fuel for the internal combustion engine 5, the more difficult it is to vaporize, leading to poor starting of the internal combustion engine 5. Therefore, as shown in Fig. 15, the fuel temperature threshold value Tft may be set higher as the ethanol content in the fuel increases.

[0088] 11, in a takeoff step 207, the control device 6 determines whether or not the distance D between the electric aircraft 200 and the urban area, acquired by the position receiver 209, is equal to or greater than the distance threshold Dt. If the distance D is equal to or greater than the distance threshold Dt (YES), the electric aircraft 200 is away from urban areas and residential environments, and the impact on people can be suppressed even if the internal combustion engine 5 generates noise and exhaust gas. Therefore, the control device 6 proceeds to a takeoff step 205, transmits command data to start the internal combustion engine 5, and proceeds to a takeoff step 206.

[0089] If the distance D is less than the distance threshold Dt (NO), in a takeoff step 208, the control device 206 determines whether or not the altitude H of the electric aircraft 200 acquired by the position receiver 209 is equal to or greater than the altitude threshold Ht.

[0090] If the altitude H of the electric aircraft 200 is less than the altitude threshold Ht (NO), the process returns to the takeoff step 204. If the altitude H of the electric aircraft 200 is equal to or greater than the altitude threshold Ht (YES), the process proceeds to the takeoff step 205, where command data is transmitted to start the internal combustion engine 5, and the process proceeds to the takeoff step 206.

[0091] Next, the control device 206 determines whether or not the internal combustion engine 5 has started in a takeoff step 206. Note that the determination as to whether or not the internal combustion engine 5 has started can be made based on a detection value detected by the start confirmation sensor 210.

[0092] When it is determined that the internal combustion engine 5 has started (YES), the control device 206 ends the processing at the time of takeoff. When it is determined that the internal combustion engine 5 has not started (NO), the control device 206 proceeds to a takeoff step 209.

[0093] Next, in the takeoff step 209, the control device 206 attempts to start the internal combustion engine 5 by at least one of increasing the amount of fuel injected into the engine and increasing the fuel concentration of the fuel-air mixture mixed in the engine, or increasing the ignition energy, which is the energy required for ignition by the spark plug, using the starting aid 211, and then returns to the takeoff step 206.

[0094] Next, in a takeoff step 206, the control device 206 again determines whether or not the internal combustion engine 5 has started. If it is determined that the internal combustion engine 5 has started (YES), the control device 206 ends the processing at takeoff, and if it is determined that the internal combustion engine 5 has not started (NO), the control device 206 again attempts to start the internal combustion engine 5 by the starting auxiliary device 211 in a takeoff step 209. Therefore, the control device 206 repeats the takeoff step 206 and the takeoff step 209 until the internal combustion engine 5 starts, and ends the processing at takeoff when the internal combustion engine 5 starts.

[0095] Next, when the electric aircraft 200 approaches the destination, the control device 206 executes the landing process shown in FIG.

[0096] First, when an operator performs an operation to start landing the electric aircraft 200, the flow executed by the control device 206 during landing shown in Fig. 12 is started, and in a landing step 201, the control device 206 determines whether the remaining battery charge SOC is equal to or higher than the landing SOCt based on the detected value of the remaining battery charge SOC of the storage battery 3 by the battery remaining charge sensor 203. The landing SOCt is the remaining battery charge SOC required to stop the internal combustion engine 5 from the altitude threshold Ht and to descend and land the electric aircraft 200 using only power from the storage battery 3.

[0097] If the battery remaining capacity SOC is less than the landing SOCt (NO), the internal combustion engine 5 is not stopped in order to charge the storage battery 3 by the generator 4, and the landing step 201 is executed from the beginning. If the battery remaining capacity SOC is equal to or greater than the landing SOCt (YES), the process proceeds to the landing step 202.

[0098] Next, in a landing step 202, the control device 206 determines whether or not the altitude H of the electric aircraft 100 acquired by the position receiver 9 is smaller than the altitude threshold Ht. If the altitude H is equal to or greater than the altitude threshold Ht (NO), the internal combustion engine 5 is not stopped and the process returns to the landing step 201. If the altitude H is less than the altitude threshold Ht (YES), the process proceeds to the landing step 203.

[0099] Next, in landing step 203, the control device 206 determines whether the distance D between the electric aircraft 200 and the urban area acquired by the position receiver 209 is less than the distance threshold Dt. If the distance D is equal to or greater than the distance threshold Dt (NO), the electric aircraft 200 is away from urban areas and residential environments, and the impact on people can be suppressed even if the internal combustion engine 5 generates noise and exhaust gas, so the internal combustion engine 5 is not stopped and the process returns to landing step 201. If the distance D is less than the distance threshold Dt (YES), the process proceeds to landing step 204, where the internal combustion engine 5 is stopped, and the process proceeds to landing step 205.

[0100] Next, in a landing step 205, the control device 206 drives the rotor 1 using only the power of the storage battery 3 to land the electric aircraft 200, and ends the landing process.

[0101] FIG. 16 is an example of a time chart showing the state of the electric aircraft 200 according to this embodiment from takeoff to landing at the destination.

[0102] The vertical axis of Figure 16 shows the state of the electric aircraft 200, and from top to bottom are the altitude H of the electric aircraft 200, the coolant temperature Tw of the internal combustion engine 5, the air temperature Ta and air pressure Pa surrounding the electric aircraft 200, the remaining battery charge SOC of the storage battery 3, and the output Gp of the generator 4.

[0103] The horizontal axis of FIG. 16, which is the time axis, is as follows.

[0104] Time 0 is the time when the electric aircraft 200 takes off.

[0105] Time t1 is the time when the internal combustion engine 5 starts. In Fig. 16, the internal combustion engine 5 has started because the coolant temperature Tw has reached the water temperature threshold Twt, and the altitude H of the electric aircraft 200 has not yet reached the altitude threshold Ht.

[0106] Time t2 is the time when the remaining battery charge SOC of the storage battery 3 reaches the upper limit threshold UL. The upper limit threshold UL is the maximum amount that can be charged into the storage battery 3.

[0107] At time t3, the altitude H of the electric aircraft 200 falls below the altitude threshold Ht and the internal combustion engine 5 is stopped.

[0108] At time t4, the electric aircraft 200 lands.

[0109] In Figure 16, the altitude threshold Ht is shown by dotted lines on the time chart of the altitude H, the water temperature threshold Twt is shown by dotted lines on the time chart of the coolant temperature Tw, the air temperature threshold Tat is shown by dotted lines on the time chart of the air temperature Ta, the air pressure threshold Pat is shown by dotted lines on the time chart of the air pressure Pa, and the upper threshold UL and lower threshold Lt are shown by dotted lines on the time chart of the remaining battery charge SOC.

[0110] The control device 206 of this embodiment does not start the internal combustion engine 5 at takeoff, and drives the rotor 1 only with the power of the storage battery 3. Therefore, as shown in Fig. 16, as the altitude H of the electric aircraft 200 increases, the remaining battery charge SOC decreases. Furthermore, as the altitude H of the electric aircraft 200 increases, the coolant temperature Tw of the internal combustion engine 5, and the atmospheric pressure Pa and temperature Ta around the electric aircraft 200 decrease.

[0111] Then, for example, when the coolant temperature Tw reaches the water temperature threshold value Twt, which is the limit at which the internal combustion engine 5 can be started stably (time t1), if the coolant temperature Tw falls any further, the internal combustion engine 5 will not be able to start stably, so the control device 206 starts the internal combustion engine 5 without waiting for the altitude H of the electric aircraft 200 to reach or exceed the altitude threshold value Ht. After the internal combustion engine 5 starts, the coolant temperature Tw rises due to heat generated by the internal combustion engine 5.

[0112] Furthermore, after time t1, the control device 206 drives the internal combustion engine 5 so that the output Gp of the generator 4 exceeds the power consumed by the rotor 1 in order to increase the remaining battery charge SOC of the storage battery 3.

[0113] Then, when the battery remaining charge SOC reaches the upper limit threshold UL and charging of the storage battery 3 is completed (time t2), the control device 206 drives the internal combustion engine 5 so that the output Gp of the generator 4 becomes the power consumed by the rotor 1.

[0114] Thereafter, as the electric aircraft 200 approaches the destination, the altitude H gradually decreases. Then, when the altitude H becomes less than the altitude threshold Ht (time t3), the control device 206 stops the internal combustion engine 5, drives the rotor 1 using only the power from the storage battery 3, and lands at the destination (time t4).

[0115] [effect] The electric aircraft 200 of this embodiment further includes an environmental sensor 8 that detects physical quantities (e.g., air temperature Ta, air pressure Pa, and humidity) around the electric aircraft 200, and the control device 206 determines whether the physical quantities detected by the environmental sensor 8 have reached threshold values ​​for the physical quantities (e.g., air temperature threshold Tat, air pressure threshold Pat, and humidity threshold) (takeoff step 204), and if the physical quantities reach the threshold values, it is preferable to start the internal combustion engine 5 and generate electricity with the generator 4. This makes it possible to prevent the internal combustion engine 5 from failing to start, which would cause flight difficulties, and allows the electric aircraft 200 to fly safely.

[0116] Note that the step of determining whether or not the physical quantity detected by the environmental sensor 8 has reached the threshold value of the physical quantity (takeoff step 204) is preferably executed after the takeoff of the electric aircraft 200, and before the step of determining whether or not the distance D between the electric aircraft 200 and the urban area is equal to or greater than the distance threshold Dt (takeoff step 207) and the step of determining whether or not the altitude H of the electric aircraft 200 is equal to or greater than the altitude threshold Ht (takeoff step 208). As a result, even before the distance D between the electric aircraft 200 and the urban area reaches the distance threshold Dt or before the altitude of the electric aircraft 200 reaches the altitude threshold Ht, the internal combustion engine 5 starts when the physical quantity detected by the environmental sensor 8 has reached the threshold value of the physical quantity, so that the flight safety of the electric aircraft 200 can be improved.

[0117] Moreover, the environmental sensor 208 in this embodiment is a temperature sensor that detects the temperature Ta around the electric aircraft 200, and the control device 206 determines whether the temperature Ta detected by the temperature sensor is equal to or lower than the temperature threshold Tat, and when the temperature Ta becomes equal to or lower than the temperature threshold Tat, it is preferable to start the internal combustion engine 5 and generate electricity with the generator 4. This makes it possible to prevent the internal combustion engine 5 from failing to start due to a drop in the temperature Ta around the electric aircraft 200, which would result in flight difficulties, and therefore allows the electric aircraft 200 to fly safely.

[0118] Note that the step of determining whether the air temperature Ta detected by the air temperature sensor has reached the air temperature threshold value Tat (takeoff step 204) is preferably executed after the takeoff of the electric aircraft 200, and before the step of determining whether the distance D between the electric aircraft 200 and the urban area is equal to or greater than the distance threshold value Dt (takeoff step 207) and the step of determining whether the altitude H of the electric aircraft 200 is equal to or greater than the altitude threshold value Ht (takeoff step 208). As a result, even before the distance D between the electric aircraft 200 and the urban area reaches the distance threshold value Dt or before the altitude of the electric aircraft 200 reaches the altitude threshold value Ht, if the air temperature Ta detected by the air temperature sensor reaches the air temperature threshold value Tat, the safety of the flight of the electric aircraft 200 can be improved.

[0119] Moreover, the environmental sensor 208 in this embodiment is an air pressure sensor that detects the air pressure Pa around the electric aircraft 200, and the control device 206 determines whether the air pressure Pa detected by the air pressure sensor is equal to or lower than the air pressure threshold Pat, and when the air pressure Pa becomes equal to or lower than the air pressure threshold Pat, it is preferable to start the internal combustion engine 5 and generate electricity with the generator 4. This makes it possible to prevent the internal combustion engine 5 from failing to start due to a drop in the air pressure Pa around the electric aircraft 200, which would result in flight difficulties, and therefore allows the electric aircraft 200 to fly safely.

[0120] Note that the step of determining whether the atmospheric pressure Pa detected by the atmospheric pressure sensor has reached the atmospheric pressure threshold Pat (takeoff step 204) is preferably executed after the takeoff of the electric aircraft 200, before the step of determining whether the distance D between the electric aircraft 200 and the urban area is equal to or greater than the distance threshold Dt (takeoff step 207) and the step of determining whether the altitude H of the electric aircraft 200 is equal to or greater than the altitude threshold Ht (takeoff step 208). As a result, even before the distance D between the electric aircraft 200 and the urban area reaches the distance threshold Dt or before the altitude of the electric aircraft 200 reaches the altitude threshold Ht, if the atmospheric pressure Pa detected by the atmospheric pressure sensor reaches the atmospheric pressure threshold Pat, the safety of the flight of the electric aircraft 200 can be improved.

[0121] Furthermore, the environmental sensor 208 in this embodiment is a humidity sensor that detects the humidity around the electric aircraft 200, and the control device 206 determines whether the humidity detected by the humidity sensor is equal to or greater than a humidity threshold, and when the humidity detected by the humidity sensor is equal to or greater than the humidity threshold, it is preferable to start the internal combustion engine 5 and generate electricity with the generator 4. This makes it possible to prevent the internal combustion engine 5 from failing to start due to an increase in the humidity around the electric aircraft 200, which would result in flight difficulties, and therefore allows the electric aircraft 200 to fly safely.

[0122] Note that the step of determining whether the humidity detected by the humidity sensor has reached the humidity threshold (takeoff step 204) is preferably executed after the takeoff of the electric aircraft 200, and before the step of determining whether the distance D between the electric aircraft 200 and the urban area is equal to or greater than the distance threshold Dt (takeoff step 207) and the step of determining whether the altitude H of the electric aircraft 200 is equal to or greater than the altitude threshold Ht (takeoff step 208). As a result, even before the distance D between the electric aircraft 200 and the urban area reaches the distance threshold Dt or before the altitude of the electric aircraft 200 reaches the altitude threshold Ht, the internal combustion engine 5 starts when the humidity detected by the humidity sensor has reached the humidity threshold, so that the flight safety of the electric aircraft 200 can be improved.

[0123] The electric aircraft 200 further includes a plurality of start condition sensors (e.g., a water temperature sensor 205 that detects a coolant temperature and a battery remaining capacity sensor 203 that detects the remaining battery capacity of the storage battery 3) that detect start conditions of the internal combustion engine 5, and the control device 206 determines whether a detection value detected by any of the plurality of start condition sensors has reached a threshold value, and when the detection value has reached the threshold value, it is preferable to start the internal combustion engine 5 and generate electricity with the generator 4. This makes it possible to prevent, for example, a situation in which the internal combustion engine 5 is unable to start due to a drop in the coolant temperature Tw of the internal combustion engine 5, resulting in difficulty in flying, or a situation in which the storage battery 3 runs out of battery capacity, resulting in difficulty in flying, thereby enabling the electric aircraft 200 to fly safely.

[0124] Note that the step of determining whether or not a detection value detected by any of the plurality of activation condition sensors has reached a threshold value (takeoff step 204) is preferably executed after the takeoff of the electric aircraft 200, and before the step of determining whether or not the distance D between the electric aircraft 200 and the urban area is equal to or greater than the distance threshold value Dt (takeoff step 207) and the step of determining whether or not the altitude H of the electric aircraft 200 is equal to or greater than the altitude threshold value Ht (takeoff step 208). As a result, even before the distance D between the electric aircraft 200 and the urban area reaches the distance threshold value Dt or before the altitude of the electric aircraft 200 reaches the altitude threshold value Ht, if the detection value detected by any of the plurality of activation condition sensors reaches the threshold value, the internal combustion engine 5 is started, so that the flight safety of the electric aircraft 200 can be improved.

[0125] Moreover, in this embodiment, one of the multiple start-up condition sensors that detect the start-up condition of the internal combustion engine 5 is a water temperature sensor 205 that detects a coolant temperature Tw of the internal combustion engine 5, and the control device 206 determines whether the coolant temperature Tw detected by the water temperature sensor 205 is equal to or higher than a water temperature threshold, and preferably starts the internal combustion engine 5 and generates electricity with the generator 4 when the coolant temperature Tw becomes equal to or higher than the water temperature threshold. This makes it possible to prevent the internal combustion engine 5 from failing to start due to a drop in the coolant temperature Tw of the internal combustion engine 5, which would lead to flight difficulties, and therefore allows the electric aircraft 200 to fly safely.

[0126] Note that the step of determining whether or not the coolant temperature Tw detected by the water temperature sensor 205 that detects the coolant temperature Tw of the internal combustion engine 5 has reached the water temperature threshold Twt (takeoff step 204) is preferably executed after the takeoff of the electric aircraft 200, before the step of determining whether or not the distance D between the electric aircraft 200 and the urban area is equal to or greater than the distance threshold Dt (takeoff step 207) and the step of determining whether or not the altitude H of the electric aircraft 200 is equal to or greater than the altitude threshold Ht (takeoff step 208). As a result, even before the distance D between the electric aircraft 200 and the urban area reaches the distance threshold Dt or before the altitude of the electric aircraft 200 reaches the altitude threshold Ht, if the coolant temperature Tw detected by the water temperature sensor 205 that detects the coolant temperature Tw of the internal combustion engine 5 reaches the water temperature threshold Twt, the internal combustion engine 5 starts, thereby improving the flight safety of the electric aircraft 200.

[0127] Moreover, one of the multiple start condition sensors that detect the start condition of the internal combustion engine 5 in this embodiment is a battery remaining capacity sensor 203 that detects the battery remaining capacity SOC of the storage battery 3, and the control device 206 determines whether the battery remaining capacity SOC detected by the battery remaining capacity sensor 203 has reached a lower threshold value Lt, and when the battery remaining capacity SOC has reached the lower threshold value Lt, it is preferable to start the internal combustion engine 5 and generate electricity with the generator 4. In this way, the internal combustion engine 5 is started and power is supplied from the generator 4 to the motor 2 before the battery remaining capacity SOC of the storage battery 3 reaches the lower threshold value Lt, so that flight difficulties can be suppressed and the electric aircraft 200 can be flown safely.

[0128] Note that the step (takeoff step 204) of determining whether the battery remaining capacity SOC detected by the battery remaining capacity sensor 203 that detects the battery remaining capacity SOC of the storage battery 3 has reached the lower threshold Lt is preferably executed after the takeoff of the electric aircraft 200 and before the step (takeoff step 207) of determining whether the distance D between the electric aircraft 200 and the urban area is equal to or greater than the distance threshold Dt and the step (takeoff step 208) of determining whether the altitude H of the electric aircraft 200 is equal to or greater than the altitude threshold Ht. As a result, even before the distance D between the electric aircraft 200 and the urban area reaches the distance threshold Dt or before the altitude of the electric aircraft 200 reaches the altitude threshold Ht, the internal combustion engine 5 starts when the battery remaining capacity SOC detected by the battery remaining capacity sensor 203 that detects the battery remaining capacity SOC of the storage battery 3 reaches the lower threshold Lt, so that the flight safety of the electric aircraft 200 can be improved.

[0129] Moreover, in this embodiment, one of the multiple start condition sensors that detect the start condition of the internal combustion engine 5 is a fuel temperature sensor that detects the fuel temperature Tf of the internal combustion engine 5, and it is preferable to determine whether the fuel temperature Tf detected by the fuel temperature sensor is equal to or lower than the fuel temperature threshold Tft, and when the fuel temperature Tf becomes equal to or lower than the fuel temperature threshold Tft, to start the internal combustion engine 5 and generate electricity with the generator 4. This makes it possible to prevent the internal combustion engine 5 from failing to start due to a drop in the fuel temperature Tf of the internal combustion engine 5, which would cause flight difficulties, and therefore allows the electric aircraft 200 to fly safely.

[0130] Note that the step of determining whether or not the fuel temperature Tf detected by the fuel temperature sensor has reached the fuel temperature threshold Tft (takeoff step 204) is preferably executed after the takeoff of the electric aircraft 200, and before the step of determining whether or not the distance D between the electric aircraft 200 and the urban area is equal to or greater than the distance threshold Dt (takeoff step 207) and the step of determining whether or not the altitude H of the electric aircraft 200 is equal to or greater than the altitude threshold Ht (takeoff step 208). As a result, even before the distance D between the electric aircraft 200 and the urban area reaches the distance threshold Dt or before the altitude of the electric aircraft 200 reaches the altitude threshold Ht, the internal combustion engine 5 starts when the fuel temperature Tf detected by the fuel temperature sensor reaches the fuel temperature threshold Tft, so that the flight safety of the electric aircraft 200 can be improved.

[0131] Moreover, it is preferable that the fuel temperature threshold Tft is set higher as the humidity around the electric aircraft increases and as the ethanol content in the fuel for the internal combustion engine 5 increases. This can further prevent the internal combustion engine 5 from failing to start and causing flight difficulties, allowing the electric aircraft 200 to fly safely.

[0132] Furthermore, in the present embodiment, the control device 206 preferably does not supply power from the storage battery 3 to the motor 2 when the remaining battery charge SOC detected by the battery charge sensor 203 before the electric aircraft 200 takes off is less than a takeoff SOCt, which is the remaining battery charge required for takeoff. This makes it possible to prevent the internal combustion engine 5 from having to be started due to a shortage of the remaining battery charge SOC at the time of takeoff of the electric aircraft 200 or before the altitude of the electric aircraft 200 reaches the altitude threshold Ht, thereby making it possible to suppress noise and exhaust gas generation by the internal combustion engine in urban areas and places close to residential environments.

[0133] Moreover, the electric aircraft 200 of this embodiment further includes a position receiver 209, and the control device 206 determines whether the distance D between the electric aircraft 200 and an urban area obtained by the position receiver 209 is equal to or greater than a distance threshold Dt, and if the distance D is equal to or greater than the distance threshold Dt, it is preferable to start the internal combustion engine 5 and generate electricity with the generator 4. As a result, the internal combustion engine 5 starts up in a location away from urban areas and human living environments, and the impact of noise and exhaust gas on people can be suppressed by starting the internal combustion engine in a location away from urban areas and human living environments.

[0134] In addition, the step of determining whether the distance D between the electric aircraft 200 and the urban area obtained by the position receiver 209 is equal to or greater than the distance threshold Dt (takeoff step 207) is preferably executed after the step of determining whether the physical quantity detected by the environmental sensor 208 has reached a physical quantity threshold, or whether the detection value detected by any of the multiple start-up condition sensors of the internal combustion engine 5 has reached a threshold, after the takeoff of the electric aircraft 200 (takeoff step 204).

[0135] This prevents the internal combustion engine 5 from being unable to start when the distance D between the electric aircraft 200 and the urban area detected by the position receiver 209 becomes equal to or greater than the distance threshold Dt and an attempt is made to start the internal combustion engine 5, thereby improving the flight safety of the electric aircraft 200.

[0136] Furthermore, the step of determining whether or not the distance D between the electric aircraft 200 and the urban area acquired by the position receiver 209 is equal to or greater than the distance threshold Dt (takeoff step 207) is preferably executed before the step of determining whether or not the altitude H of the electric aircraft 200 is equal to or greater than the altitude threshold Ht (takeoff step 208). This allows the internal combustion engine 5 to be started sooner, allowing the electric aircraft 200 to fly safely.

[0137] The electric aircraft 200 further includes a start confirmation sensor 210 that confirms the start of the internal combustion engine 5, and a start assist device 211 that assists in the start of the internal combustion engine, and the control device 206 determines whether or not the internal combustion engine 5 should be started based on the detection value of the start confirmation sensor 210, and if the internal combustion engine 5 has not started, starts the internal combustion engine 5 using the start assist device 211 and generates electricity with the generator 4. This makes it possible to prevent the internal combustion engine 5 from being unable to start, thereby improving the flight safety of the electric aircraft 200.

[0138] Third embodiment Fig. 17 is a schematic configuration diagram of an electric aircraft 300 according to a third embodiment of the present invention. Fig. 18 is a block diagram showing an example of the hardware configuration of a control device 306 according to the third embodiment of the present invention, a device for inputting data to the control device 306, and a device for outputting command data from the control device 306. Fig. 19 is a diagram showing an example of a flowchart executed at takeoff by the control device according to the third embodiment.

[0139] The electric aircraft 300 according to this embodiment differs from the electric aircraft 200 according to the second embodiment in that it includes an exhaust catalyst 305, which is a catalyst provided in the exhaust pipe of the internal combustion engine 5, and a catalyst temperature sensor 312 that detects the temperature of the exhaust catalyst 305. Note that, although the start confirmation sensor 210 and the start auxiliary device 211 are not included in FIG. 17, the electric aircraft 300 may include the start confirmation sensor 210 and the start auxiliary device 211.

[0140] The control device 306 according to this embodiment differs from the control device 206 according to the second embodiment in that the catalyst temperature Tc detected by the catalyst temperature sensor 312 is input to the control device 306, and a catalyst temperature threshold value Tct, which is a threshold value of the catalyst temperature Tc, is stored in the second storage device 306d. Note that in FIG. 18, the start confirmation sensor 210 is not present in the device that inputs data to the control device 306, and the start auxiliary device 211 is not present in the device that outputs command data from the control device 206, but the start confirmation sensor 210 may be present in the device that inputs data to the control device 306, and the start auxiliary device 211 may be present in the device that outputs command data from the control device 206.

[0141] Furthermore, the flow executed by the control device 306 according to this embodiment at takeoff differs from the flow executed by the control device 206 according to the second embodiment at takeoff in that it includes a takeoff step 307 for determining whether the catalyst temperature Tc is equal to or lower than the catalyst temperature threshold value Tct.

[0142] 19 does not include the takeoff step 207 for determining whether the distance D from the urban area detected by the position receiver 209 is equal to or greater than the distance threshold Dt, but the takeoff step 207 may be executed together with the takeoff step 307. Also, the takeoff step 206 for determining whether the internal combustion engine 5 has started and the takeoff step 209 for attempting to start the internal combustion engine 5 by the starting auxiliary device 211 are not included, but these steps may be included as in the second embodiment.

[0143] Specifically, the flow executed by the control device 306 at takeoff in Figure 19 is initiated when the operator operates to start operating the electric aircraft. As in the second embodiment, in a takeoff step 201, the control device 306 reads the remaining battery charge SOC of the storage battery 3 and determines whether the remaining battery charge SOC is equal to or greater than the takeoff SOCt. In a takeoff step 202, the control device 306 supplies power from the storage battery 3 to the motor 2 and starts the rotor 1. In a takeoff step 203, the control device 306 determines whether the electric aircraft 300 has taken off. In a takeoff step 204, the control device 306 determines whether the remaining battery charge SOC is equal to or less than the lower threshold Lt, whether the cooling water temperature Tw is equal to or less than the water temperature threshold Twt, whether the air temperature Ta is equal to or less than the air temperature threshold Tat, and whether the air pressure Pa is equal to or less than the air pressure threshold Pat. If the determination in the takeoff step 204 is YES, the control device 306 proceeds to a takeoff step 205.

[0144] If the battery remaining charge SOC is not equal to or lower than the lower threshold Lt, the coolant temperature Tw is not equal to or lower than the water temperature threshold Twt, the air temperature Ta is not equal to or lower than the air temperature threshold Tat, and the air pressure Pa is not equal to or lower than the air pressure threshold Pat (NO), the control device 306 determines in takeoff step 307 whether the catalyst temperature Tc is not equal to or lower than the catalyst temperature threshold Tct.

[0145] If the catalyst temperature Tc is equal to or lower than the catalyst temperature threshold value Tct (YES), the purification performance of the exhaust catalyst 305 will be significantly reduced and a large amount of harmful substances will be emitted from the internal combustion engine 5, so in the takeoff step 205, the internal combustion engine 5 is started to prevent the catalyst temperature Tc from decreasing further.

[0146] If the catalyst temperature Tc exceeds the catalyst temperature threshold Tct (NO), the process proceeds to takeoff step 208, where it is determined whether the altitude H of the electric aircraft 200 has reached the altitude threshold Ht, and in step 205, the internal combustion engine 5 is started, and the takeoff process is terminated.

[0147] [effect] The electric aircraft 300 of this embodiment further includes an exhaust catalyst 305 provided in the piping of the internal combustion engine 5, and a catalyst temperature sensor 312 that detects the catalyst temperature Tc of the exhaust catalyst 305, and the control device 306 determines whether the catalyst temperature Tc detected by the catalyst temperature sensor 312 is below the catalyst temperature threshold Tct, and if the catalyst temperature Tc becomes below the catalyst temperature threshold Tct, it is preferable to start the internal combustion engine 5 and generate electricity using the generator 4.

[0148] This prevents the catalyst temperature Tc detected by the catalyst temperature sensor 312 from falling below the catalyst temperature threshold Tct, causing the purification performance of the exhaust catalyst 305 to deteriorate significantly and causing a large amount of harmful substances to be emitted from the internal combustion engine 5.

[0149] In addition, the step of determining whether the catalyst temperature Tc detected by the catalyst temperature sensor 312 is equal to or lower than the catalyst temperature threshold value Tct (takeoff step 307) is preferably executed after the step of determining whether the physical quantity detected by the environmental sensor 208 has reached a physical quantity threshold value or whether the detection value detected by any of the multiple start-up condition sensors of the internal combustion engine 5 has reached a threshold value after the takeoff of the electric aircraft 200 (takeoff step 204).

[0150] This prevents the internal combustion engine 5 from being unable to start when the catalyst temperature Tc detected by the catalyst temperature sensor 312 falls below the catalyst temperature threshold Tct and an attempt is made to start the internal combustion engine 5, thereby improving the flight safety of the electric aircraft 200.

[0151] Furthermore, the step of determining whether or not the catalyst temperature Tc detected by the catalyst temperature sensor 312 is equal to or lower than the catalyst temperature threshold value Tct (takeoff step 307) is preferably executed before the step of determining whether or not the altitude H of the electric aircraft 200 is equal to or higher than the altitude threshold value Ht (takeoff step 208). This allows the internal combustion engine 5 to be started earlier, thereby preventing a large amount of harmful substances from being emitted from the internal combustion engine 5.

[0152] The present invention is not limited to the above-described embodiment, and includes various modified examples. For example, the above-described embodiment has been described in detail to clearly explain the present invention, and is not necessarily limited to those including all of the configurations described. In addition, it is possible to replace a part of the configuration of one embodiment with the configuration of another embodiment, and it is also possible to add the configuration of another embodiment to the configuration of one embodiment. In addition, it is possible to add, delete, or replace a part of the configuration of each embodiment with another configuration.

[0153] In addition, the above configurations, functions, etc. may be realized in hardware, for example, by designing some or all of them as an integrated circuit. In addition, the above configurations, functions, etc. may be realized in software by a processor (microcomputer) interpreting and executing a program that realizes each function. Information such as the program, table, file, etc. that realizes each function can be stored in a memory, a recording device such as a hard disk or SSD (Solid State Drive), or a recording medium such as an IC card, SD card, or DVD.

[0154] The embodiment of the present invention may be in the following form. For example, one of the multiple start condition sensors that detect the start condition of the internal combustion engine 5 may be a sensor that detects the temperature of the engine oil of the internal combustion engine 5, and in the takeoff step 204, it may be determined whether the temperature of the engine oil detected by this sensor is equal to or lower than a threshold value (the minimum temperature for starting the internal combustion engine 5), and when the detected value reaches the threshold value, the internal combustion engine 5 may be started and the generator 4 may generate electricity. [Explanation of symbols]

[0155] 1...rotor, 2...motor, 3...storage battery, 4...generator, 5...internal combustion engine, 6...control device, 7...altitude acquisition device, 8...environmental sensor, 100, 200, 300...electric aircraft, 203...battery remaining capacity sensor, 205...water temperature sensor, 209...position receiver, 210...start confirmation sensor, 211...starting auxiliary device, 305...exhaust catalyst, 312...catalyst temperature sensor

Claims

1. A control device for controlling an electric aircraft including a motor that drives a rotor, a storage battery that supplies power to the motor, a generator that uses an internal combustion engine as a power source and can supply power to the motor and the storage battery, and an altitude acquisition device that acquires a flight altitude, The control device supplies power from the storage battery to the motor while stopping the internal combustion engine to cause the electric aircraft to take off, and after the electric aircraft takes off, determines whether the altitude of the electric aircraft acquired by the altitude acquisition device is equal to or greater than an altitude threshold, and if the altitude of the electric aircraft is equal to or greater than the altitude threshold, starts the internal combustion engine.

2. The control device for an electric aircraft according to claim 1, The electric aircraft further includes an environmental sensor that detects a physical quantity around the electric aircraft; The control device for an electric aircraft is characterized in that, after the electric aircraft takes off, the control device determines whether a physical quantity detected by the environmental sensor has reached a threshold value for the physical quantity, and if the physical quantity has reached the threshold value, starts the internal combustion engine and generates electricity using the generator.

3. The control device for an electric aircraft according to claim 1, The electric aircraft further includes a plurality of start-up condition sensors that detect start-up conditions of the internal combustion engine; The control device for an electric aircraft is characterized in that, after the electric aircraft takes off, the control device determines whether a detection value detected by any of the multiple start-up condition sensors has reached a threshold value, and if the detection value has reached the threshold value, starts the internal combustion engine and generates electricity using the generator.

4. The control device for an electric aircraft according to claim 2, the environmental sensor is an air temperature sensor that detects an air temperature around the electric aircraft; The control device for an electric aircraft is characterized in that after the electric aircraft takes off, the control device determines whether the air temperature detected by the air temperature sensor is below an air temperature threshold, and if the air temperature detected by the air temperature sensor becomes below the air temperature threshold, starts the internal combustion engine and generates electricity using the generator.

5. The control device for an electric aircraft according to claim 2, the environmental sensor is a barometric pressure sensor that detects an ambient air pressure of the electric aircraft; The control device for an electric aircraft is characterized in that after the electric aircraft takes off, the control device determines whether the air pressure detected by the air pressure sensor is below an air pressure threshold, and if the air pressure detected by the air pressure sensor becomes below the air pressure threshold, starts the internal combustion engine and generates electricity using the generator.

6. The control device for an electric aircraft according to claim 2, the environmental sensor is a humidity sensor that detects humidity around the electric aircraft, The control device for an electric aircraft is characterized in that after the electric aircraft takes off, the control device determines whether the humidity detected by the humidity sensor is equal to or higher than a humidity threshold value, and if the humidity detected by the humidity sensor becomes equal to or higher than the humidity threshold value, starts the internal combustion engine and generates electricity using the generator.

7. The control device for an electric aircraft according to claim 3, one of the plurality of start-up condition sensors is a water temperature sensor that detects a temperature of a cooling water of the internal combustion engine; The control device for an electric aircraft is characterized in that after the electric aircraft takes off, the control device determines whether the water temperature detected by the water temperature sensor is below a water temperature threshold, and if the water temperature detected by the water temperature sensor becomes below the water temperature threshold, starts the internal combustion engine and generates electricity using the generator.

8. The control device for an electric aircraft according to claim 3, one of the plurality of start-up condition sensors is a battery remaining amount sensor that detects a remaining amount of the storage battery; The control device for an electric aircraft is characterized in that after the electric aircraft takes off, the control device determines whether the remaining battery charge detected by the battery remaining charge sensor is below a lower threshold, and if the remaining battery charge detected by the battery remaining charge sensor becomes below a lower threshold, the control device starts the internal combustion engine and generates electricity using the generator.

9. The control device for an electric aircraft according to claim 1, The electric aircraft further includes a position receiver that calculates a position of the electric aircraft based on positioning signals received from a plurality of positioning satellites; The control device determines whether, after the electric aircraft takes off, the distance between the electric aircraft and an urban area detected by the position receiver is greater than or equal to a distance threshold, and if the distance between the electric aircraft and the urban area detected by the position receiver becomes greater than or equal to the distance threshold, starts the internal combustion engine and generates electricity using the generator.

10. The control device for an electric aircraft according to claim 1, The electric aircraft further includes a catalyst provided in an exhaust pipe of the internal combustion engine and a catalyst temperature sensor that detects a temperature of the catalyst; The control device for an electric aircraft is characterized in that after the electric aircraft takes off, the control device determines whether the temperature detected by the catalyst temperature sensor is below a catalyst temperature threshold, and if the temperature detected by the catalyst temperature sensor becomes below the catalyst temperature threshold, starts the internal combustion engine and generates electricity using the generator.

11. The control device for an electric aircraft according to claim 3, one of the plurality of start condition sensors is a fuel temperature sensor that detects a temperature of fuel in the internal combustion engine; The control device for an electric aircraft is characterized in that, after the electric aircraft takes off, when the fuel temperature detected by the fuel temperature sensor becomes lower than a fuel temperature threshold value, the control device starts the internal combustion engine and generates electricity using the generator.

12. The control device for an electric aircraft according to claim 8, The control device is characterized in that, before the takeoff of the electric aircraft, if the remaining battery charge detected by the battery remaining charge sensor is less than a takeoff battery remaining charge, which is the battery remaining charge required for takeoff, the control device does not supply power from the storage battery to the motor.

13. The control device for an electric aircraft according to claim 1, The electric aircraft further includes a start confirmation sensor that confirms start-up of the internal combustion engine, and a start assist device that assists in starting the internal combustion engine, The control device determines whether or not to start the internal combustion engine based on the detection value of the start-up confirmation sensor, and if the internal combustion engine is not started, starts the internal combustion engine using the start-up auxiliary device and generates electricity using the generator.

14. The control device for an electric aircraft according to claim 1, The control device, when landing the electric aircraft, determines whether the altitude of the electric aircraft is less than the altitude threshold, and if the altitude of the electric aircraft is less than the altitude threshold, stops the internal combustion engine and drives the motor using only the power supplied from the storage battery to land the electric aircraft.

15. A control method for controlling an electric aircraft including a motor that drives a rotor, a storage battery that supplies power to the motor, a generator that uses an internal combustion engine as a power source and can supply power to the motor and the storage battery, and an altitude acquisition device that acquires a flight altitude, comprising: A control method for an electric aircraft, comprising: supplying power from the storage battery to the motor while keeping the internal combustion engine stopped, causing the electric aircraft to take off; after the electric aircraft has taken off, determining whether the altitude of the electric aircraft acquired by the altitude acquisition device is equal to or greater than an altitude threshold; and starting the internal combustion engine if the altitude of the electric aircraft is equal to or greater than the altitude threshold.

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