Method for operating a flying object and flying object

Abstract

Method for operating a flying object (10), in particular a fuel cell-electrically powered flying object (10), with at least one fuel cell system (12), with at least one at least partially electric drive unit (14), wherein the fuel cell system (12) has at least one hydrogen storage device (20), wherein the hydrogen storage device (20) has a first lower pressure limit and wherein status data of the drive unit (14) and / or the flying object (10) are recorded, wherein an operating application ensures the maintenance of a minimum pressure in the hydrogen storage device, wherein falling below the first lower pressure limit leads to damage to an inner container of the two-layer hydrogen storage device, characterized in thatthat target state data are assigned to the state data and that if the target state data are exceeded or undershot, the first lower pressure limit can be extended to a second lower pressure limit and that if the target state data are exceeded or undershot by a first limit, a recommendation is issued to extend the first lower pressure limit to the second lower pressure limit.

Description

[0001] The invention relates to a method for operating a flying object, in particular a fuel cell-electrically powered flying object, with at least one fuel cell system, with at least one at least partially electric drive unit, wherein the fuel cell system has at least one hydrogen storage unit, wherein the hydrogen storage unit has a first lower pressure limit and wherein status data of the drive unit and / or the flying object are recorded.

[0002] In addition, the invention relates to a flying object, in particular a fuel cell-electrically powered flying object, with at least one fuel cell system, with at least one at least partially electric drive unit and with at least one control unit, wherein the fuel cell system has a hydrogen storage device, wherein the hydrogen storage device has a first lower pressure limit and wherein status data of the drive unit and / or the flying object can be recorded by the control unit.

[0003] In contrast to vehicles, flying objects are subject to significantly higher requirements regarding safe operation. This is due to the increased difficulty in achieving a safe state in the event of a technical failure of the flying object. In the event of a technical failure of a vehicle, the technical components can usually be shut down immediately, stopping the vehicle and thus bringing it into a safe state. A flying object, however, especially one without traditional wings such as a multicopter, must perform a landing, which, depending on the flight concept, often requires high power requirements.

[0004] After a technical fault occurs, a drive power that is in the range of the maximum power of the drive in normal operation is still required for a comparatively long period of time until a safe state is reached.

[0005] DE 10 2020 004 510 A1, for example, shows an aircraft with a hybrid drive. In the aircraft, a computing unit can be provided to specify a propulsion energy configuration, whereby the results of a range calculation can be taken into account during operation of the internal combustion engines and other machines. If there is a risk that the specified reserve range specifications cannot be met, the computing unit can specify a preferred, more energy-efficient propulsion mode.

[0006] WO 2020 / 257646 A1 describes a fuel cell system as well as a method and a device for electrically powered aircraft with a fuel cell module.The fuel cell module includes a plurality of fuel cells working together to process gaseous oxygen from air compressed by a turbocharger and gaseous hydrogen from liquid hydrogen converted by a heat exchanger, with an electrical circuit configured to collect electrons from the plurality of hydrogen fuel cells to supply voltage and current to motor controllers commanded by autopilot control units configured to select and control an amount and distribution of electrical voltage and torque or current for each of the plurality of motor and propeller assemblies, wherein electrons returning from the electrical circuit combine with oxygen in the compressed air to form oxygen ions, so that the protons then combine with oxygen ions to form H2O molecules and heat.

[0007] DE 10 2019 002 882 A1 describes a method for refueling hydrogen-powered vehicles, in which the refueling of the vehicles is controlled and carried out by a hydrogen tanker or its upstream operations center. The contents of the hydrogen tank in the vehicle to be refueled are determined by pressure measurement and transmitted via telemetry, along with its location, to the hydrogen tanker or its operations center. The hydrogen tanker drives to the vehicle to be refueled, and the tank of the vehicle to be refueled is accessible to the hydrogen tanker using a mechanical or electronic key. The hydrogen tanker uses an onboard compressor to adjust the hydrogen pressure and thus the fill level in the tank of the vehicle to be refueled during refueling.

[0008] DE 10 2017 011 720 A1 discloses a device for supplying hydrogen to an anode of a fuel cell stack with passive anode recirculation via a gas jet pump. A bypass line is provided around the gas jet pump and its pressure regulator, which bypass line has a bypass valve designed as a switching valve.

[0009] The invention is based on the object of specifying a method for operating a flying object and a flying object in which components of the drive train can be operated in such a way that safe operation is possible while at the same time reducing costs and / or weight.

[0010] This object is achieved in the present invention by the features of the characterizing part of patent claim 1 in that target state data are assigned to the state data and that when the target state data are exceeded or undershot, the first lower pressure limit can be extended to a second lower pressure limit.

[0011] The fuel cell system can be any known fuel cell system. The fuel cell system preferably features active anode recirculation.

[0012] Within the scope of the invention, the hydrogen storage device is a pressure accumulator. An example of a pressure accumulator that is common in vehicle applications would be a pressure accumulator in the range of 700 bar. However, the invention is not limited to this type of pressure accumulator. A pressure threshold, i.e., the lower pressure limit, can be implemented algorithmically in the fuel cell system.

[0013] The drive unit can be purely electric, meaning it can have an electric motor as the torque source. It is also conceivable that a hybrid-electric drive unit could be used. This could include a battery and fuel cell system in conjunction with an electric motor as the torque source. It is also conceivable that a drive unit based on gaseous or liquid fuels could be used in addition, for example, a jet engine or a piston engine.

[0014] The number of drive trains within the propulsion unit can be one or more. The connection of the drive trains to the thrust-generating components, such as a propeller, can be designed in any way. For example, one drive train for one propeller or four separate drive trains for eight propellers would be conceivable, with each drive train being designed for two propellers.

[0015] The status data can include various data from the aircraft. Examples include propeller speeds, temperatures both inside and outside the aircraft, or the pressure of the hydrogen storage tank. If, for example, the propeller speed drops, this is registered as a deviation from the target state. It is then possible that the hydrogen storage tank can be released to the second lower pressure limit.

[0016] An advantage of the present invention is that a technical and / or operational solution is provided that allows drive train components to be operated in such a way that they exceed or fall below the actually approved operating range, thus enabling a safe landing of the aircraft, even if this may result in subsequent component damage and / or a reduction in component service life. Such an emergency scenario can be handled, in particular, by hydrogen pressure accumulators of fuel cell-electrically powered aircraft.

[0017] The operational application of hydrogen pressure storage ensures that a minimum pressure is maintained in the storage tank. A drop below the corresponding lower pressure limit is possible, but this leads to damage to the so-called liner, an inner container of the two-layer container in the storage tank. However, the storage tank should be replaced after this, as its functionality is impaired, especially at high pressures.

[0018] However, emergency operation until landing is possible once, for example, if the original landing site is unexpectedly unavailable. This measure can be used to reduce the energy reserve requirements of the hydrogen pressure storage units when designing the powertrain, allowing the powertrain to have a longer nominal range or, with the same nominal range, to be designed for a lower storage capacity. The aircraft benefits from reduced costs and / or weight, resulting in increased energy efficiency and / or an increase in nominal range.

[0019] Normally, the storage system is designed to ensure the required range reserve during normal operation, i.e., without exceeding the first lower pressure limit of the hydrogen storage system. The proposed design approach has a positive energy impact during normal operation. Ultimately, cost savings can be achieved because the described emergency scenarios occur very rarely, and the advantages generated during normal operation, particularly the lower energy requirement for the same flight mass or nominal range, more than compensate for the disadvantages of storage damage that arise in an emergency scenario.

[0020] The aircraft can thus be constructed more cost-effectively and / or with lower mass and / or smaller installation space requirements, and thus more energy-efficiently. This consequently also has positive consequences for CO 2 - and resource footprint of the aircraft as well as its economic viability.

[0021] Further preferred embodiments of the invention result from the remaining features mentioned in the subclaims.

[0022] According to the invention, if the target state data falls below or exceeds a first limit, a recommendation to extend the first lower pressure limit to the second lower pressure limit is issued. In this way, a pilot or, for example, a control unit can be informed that it may be advisable to extend the first lower pressure limit of the fuel cell system or the hydrogen storage system to the second lower pressure limit.

[0023] Additionally, a further embodiment of the invention can provide that, upon confirmation of the recommendation by a pilot, the first lower pressure limit is extended to the second lower pressure limit. The pilot thus has the choice and can assess the situation independently. If, for example, sensors of the aircraft are malfunctioning, but the pilot himself believes that extending the first lower pressure limit to the second lower pressure limit is unnecessary, the recommendation to extend the lower pressure limit need not be followed.

[0024] Alternatively or additionally, a further embodiment of the invention provides that upon confirmation of the recommendation by a control device connected to the flying object, the first lower pressure limit is extended to the second lower pressure limit. The control device can be, for example, a ground control center, i.e. an external control device that is wirelessly connected to the flying object. The connection can be implemented, for example, via a communications interface via which all signal variables entering the monitoring unit of the flying object are sent, preferably in a bundled manner, at regular intervals. The control device can comprise a monitoring unit that has a specific range of functions for evaluating the status data.

[0025] Optionally, additional personnel can supervise the control system. Communication between the personnel and the control system is analogous to that between a pilot and the monitoring of the status data in the aircraft. In the event of an emergency scenario, the control system can send a control recommendation to the aircraft. This is incorporated into the decision-making function block in the aircraft. Furthermore, similar to the aircraft, the control system sends a situation assessment and recommended action to the pilot should the aircraft require a pilot.

[0026] In an emergency, a further embodiment of the method according to the invention can provide that if the target state data falls below or exceeds a second limit, the first lower pressure limit is automatically extended to the second lower pressure limit. It is therefore automatically detected that a reserve is needed because the power requirement is significantly higher than expected, for example due to bad weather, or the power requirement is significantly higher than expected due to the failure of a drive unit and the associated declining efficiency, or for example because a second energy source in a hybrid drive has failed due to a fault. The second limit indicates an emergency, whereas the first limit draws attention to the possibility of a malfunction.

[0027] Furthermore, in a further preferred embodiment of the method according to the invention, it is provided that a pilot can manually carry out the extension from the first lower pressure limit to the second lower pressure limit at any time.

[0028] Overall, the plan is to prioritize the various possible actions. This allows multiple, potentially conflicting instructions to be consolidated. For example, the pilot could approve a recommended course of action and simultaneously initiate an emergency program, or there could also be an instruction from the control facility. Such conflicts are resolved according to clearly defined prioritization rules.

[0029] In a further advantageous embodiment of the method according to the invention, an error entry is stored when the first lower pressure limit has been extended to the second lower pressure limit, and the aircraft can only be restarted after the hydrogen storage tank has been replaced. This means that redundant programming and setting of the corresponding error entries ensure that the aircraft can only be restarted after the hydrogen storage tank has been replaced and, optionally, after the error has been reset by trained personnel.

[0030] The aforementioned object is also achieved by an aforementioned flying object, in particular by a fuel cell-electrically powered flying object, having at least one fuel cell system, at least one at least partially electric drive unit, and at least one control unit, wherein the fuel cell system has a hydrogen storage device, wherein the hydrogen storage device has a first lower pressure limit, wherein status data of the drive unit and / or the flying object can be received by the control unit. It is provided that the control unit assigns target status data to the status data, and that if the target status data are exceeded or undershot, the first lower pressure limit can be extended to a second lower pressure limit.

[0031] The control unit can interact with the aircraft's data interfaces. The aircraft can be equipped with sensors that can be addressed by the control unit. The aircraft can be operated by a pilot. It is also conceivable that the aircraft can be remotely controlled. The aircraft can also be controlled autonomously, for example, using artificial intelligence.

[0032] In a further preferred embodiment of the inventive flying object, the fuel cell system is provided with active anode recirculation. With passive anode recirculation, the comparatively lower pressure when the lower pressure limit is undershot is not optimal for a sufficient supply of hydrogen to the fuel cell system. This could result in a drop in performance.

[0033] According to the invention, it is provided that a method according to a method according to the invention can be carried out by the control unit.

[0034] All previous statements regarding the method according to the invention also apply accordingly to the flying object according to the invention.

[0035] The various embodiments of the invention mentioned in this application can be advantageously combined with one another, unless stated otherwise in the individual case.

[0036] The invention is explained below in exemplary embodiments with reference to the accompanying drawings. They show: Fig. 1 a schematic representation of an embodiment of a flying object according to the invention and Fig. 2 a schematic representation of an embodiment of a method according to the invention.

[0037] Fig. 1 shows a flying object 10 with a fuel cell system 12 and an electric drive unit 14 in the form of four propellers. The flying object 10 is wirelessly connected to a control device 16. In addition, the flying object 10 has a control unit 18. The fuel cell system 12 comprises a hydrogen tank 20. The hydrogen tank 20 has a first lower pressure limit and a second lower pressure limit. During normal operation, the fuel cell system 12 and, accordingly, the flying object 10 are operated above the first lower pressure limit. During operation of the flying object 10, status data of the flying object 10, in particular of the drive unit 14, are recorded by the control unit 18. This status data is compared with target status data.If these state data deviate from the target state data by a first limit value, the control unit 18 issues a recommendation to extend the first lower pressure limit to the second lower pressure limit.

[0038] In this way, components of the drive train can be operated in such a way that they exceed or fall below the actually approved operating range, thus enabling a safe landing of the flying object 10, even at the risk of subsequent component damage and / or a reduction in component service life. Such an emergency scenario can be handled accordingly by the hydrogen storage unit 20 of the fuel cell system 12 of the flying object 10.

[0039] Fig. 2 shows a schematic, step-by-step representation of an embodiment of a method according to the invention for operating the flying object 10 according to Fig.1. In step 100, it is detected that the status data of the flying object 10 or the propulsion unit 14 do not correspond to the previously defined target status data. Step 120 shows the case where the status data deviate from the target status data by a higher, second limit value. In this case, an emergency is assumed. Therefore, in step 120, the first lower pressure limit is automatically extended to the second lower pressure limit, allowing the flying object 10 to perform an emergency landing.

[0040] Step 160 shows the case where the status data deviate from the target status data by a first limit value. In this case, an emergency does not yet exist. Therefore, in the subsequent step 180, the control unit 18 merely issues a recommendation that it may be appropriate to extend the first lower pressure limit to the second lower pressure limit. This recommendation can be accepted or rejected by a pilot in step 200. It is also conceivable that the flying object 10 is operated autonomously without a pilot. Alternatively or additionally, this recommendation can be accepted or rejected by the control device 16 or by personnel employed by the control device 16.

[0041] Step 240 illustrates that a pilot in the flying object 10 has the option of manually extending the first lower pressure limit to the second lower pressure limit at any time. Likewise, personnel in the control facility 16 can manually extend the first lower pressure limit to the second lower pressure limit. These action options, summarized by the dashed line, can partially be executed in parallel. For this purpose, a prioritization of the actions is provided in step 260. If, for example, the recommendation of the control unit 18 to extend the first lower pressure limit to the second lower pressure limit from step 180 was rejected in step 200, but the situation has since become an emergency, the automatic extension of the first lower pressure limit to the second lower pressure limit according to step 140 is nevertheless ultimately carried out in step 280. This decision is signaled to the pilot. List of reference symbols 10 flying object 12 Fuel cell system 14 Drive unit 16 Control device 18 Control unit 20 hydrogen storage units

Claims

[1] Method for operating a flying object (10), in particular a fuel cell-electrically powered flying object (10), with at least one fuel cell system (12), with at least one at least partially electric drive unit (14), wherein the fuel cell system (12) has at least one hydrogen storage unit (20), wherein the hydrogen storage unit (20) has a first lower pressure limit and wherein status data of the drive unit (14) and / or the flying object (10) are recorded, wherein an operating application ensures the maintenance of a minimum pressure in the hydrogen storage unit, wherein falling below the first lower pressure limit leads to damage to an inner container of the two-layer hydrogen storage unit, characterized bythat target state data are assigned to the state data and that if the target state data is exceeded or undershot, the first lower pressure limit can be extended to a second lower pressure limit and that if the target state data is exceeded or undershot by a first limit, a recommendation is issued to extend the first lower pressure limit to the second lower pressure limit. [2] Method according to claim 1, characterized by that if the recommendation is confirmed by a pilot, the first lower pressure limit is extended to the second lower pressure limit. [3] Method according to claim 1 or 2, characterized by that upon confirmation of the recommendation by a control device (16) connected to the flying object (10), the first lower pressure limit is extended to the second lower pressure limit. [4] Method according to one of claims 1 to 3, characterized bythat if the target state data is exceeded or undershot by a second limit value, the first lower pressure limit is automatically extended to the second lower pressure limit. [5] Method according to one of claims 1 to 4, characterized by that the extension from the first lower pressure limit to the second lower pressure limit can be carried out manually by a pilot at any time. [6] Method according to one of claims 1 to 5, characterized by that an error entry is stored when the first lower pressure limit has been extended to the second lower pressure limit and that the flying object (10) can only be put back into operation after the hydrogen storage device (20) has been replaced. [7] Flying object (10), in particular a fuel cell-electrically powered flying object (10), with at least one fuel cell system (12), with at least one at least partially electric drive unit (14) and with at least one control unit (18), wherein the fuel cell system (12) has a hydrogen storage device (20), wherein the hydrogen storage device (20) has a first lower pressure limit and wherein status data of the drive unit (14) and / or the flying object (10) can be recorded by the control unit (18), characterized by that the control unit (18) assigns target state data to the state data and that when the target state data is exceeded or undershot, the first lower pressure limit can be extended to a second lower pressure limit, characterized by that the control unit (18) is configured to carry out a method according to one of claims 1 to 6.

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