(19)
(11)EP 3 043 408 B1

(12)EUROPEAN PATENT SPECIFICATION

(45)Mention of the grant of the patent:
05.12.2018 Bulletin 2018/49

(21)Application number: 15202435.2

(22)Date of filing:  23.12.2015
(51)Int. Cl.: 
H01M 8/04746  (2016.01)

(54)

FUEL CELL SYSTEM FOR AN AIRCRAFT AND METHOD FOR PROVIDING AN INERT GAS IN AN AIRCRAFT

BRENNSTOFFZELLENSYSTEM FÜR EIN FLUGZEUG UND VERFAHREN ZUR BEREITSTELLUNG EINES INERTEN GASES IN EINEM FLUGZEUG

SYSTÈME DE PILE À COMBUSTIBLE POUR UN AVION ET PROCÉDÉ POUR FOURNIR UN GAZ INERTE DANS UN AÉRONEF


(84)Designated Contracting States:
AL AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HR HU IE IS IT LI LT LU LV MC MK MT NL NO PL PT RO RS SE SI SK SM TR

(30)Priority: 08.01.2015 DE 102015100185

(43)Date of publication of application:
13.07.2016 Bulletin 2016/28

(73)Proprietor: Airbus Operations GmbH
21129 Hamburg (DE)

(72)Inventors:
  • Lüdders, Hauke-Peer
    21129 Hamburg (DE)
  • Zandstra, Sijmen
    21129 Hamburg (DE)
  • Fabritz, Alexander
    21129 Hamburg (DE)

(74)Representative: LKGLOBAL Lorenz & Kopf PartG mbB Patentanwälte 
Brienner Straße 11
80333 München
80333 München (DE)


(56)References cited: : 
EP-A1- 2 624 353
DE-A1-102005 012 120
US-A1- 2009 202 370
DE-A1-102005 010 399
DE-A1-102007 017 820
  
      
    Note: Within nine months from the publication of the mention of the grant of the European patent, any person may give notice to the European Patent Office of opposition to the European patent granted. Notice of opposition shall be filed in a written reasoned statement. It shall not be deemed to have been filed until the opposition fee has been paid. (Art. 99(1) European Patent Convention).


    Description

    TECHNICAL FIELD



    [0001] The invention relates to an aircraft which comprises a fuel cell, and a method for providing an inert gas in an aircraft.

    BACKGROUND OF THE INVENTION



    [0002] Known in prior art are various inerting and fire extinguishing systems for aircraft, which use the gas halon, which will in the future no longer be permitted, or oxygen-depleted exhaust gas from the operation of fuel cell systems. In particular when using a fuel cell-based system, its continuous operation must be ensured, since the fuel cell process may be performed, and thus oxygen-depleted air be produced, only if sufficient electrical power is tapped.

    [0003] Known from prior art is to feed the electrical power provided by the fuel cell system into a voltage supply network, which taps this power.

    [0004] Known from DE 10 2005 010 399 B4 are an aircraft with a fuel cell emergency system and a method for air-independent emergency power supply. DE 10 2008 006 742 A1 shows a fuel cell system for an aircraft that comprises a fuel cell with an oxidant inlet for supplying an oxygenic medium into the fuel cell, which may be connected with an exhaust gas outlet of a cabin in the aircraft.

    [0005] DE 10 2007 017820 A1 shows an energy supply system of an aircraft, which is based on a fuel cell and which is intended for an emergency operation in case of a malfunctioning engine.

    [0006] DE 10 2005 012120 A1 discloses an aircraft having a fuel cell as well as an electrically operated hydraulics pump, a fuel supply line, a fuel outlet line and means for influencing the fuel flow through the fuel cell, which include a pressure regulator in the supply line as well as a throttle element in the outlet line.

    [0007] US 2009/202370 A1 shows a hydraulic system comprising a power supply means, which has a fuel cell stack that delivers electrical power to a hydraulics pump, while the use of energy as efficient as possible through using different forms of energy is mentioned.

    [0008] EP 2 624 353 A1 discloses an emergency energy supply system with a fuel cell for a vehicle, which is designed for providing a fire extinguishing as well as a fire suppression function through using inert exhaust gas, wherein for producing a demand for electrical power it is suggested to convert electrical power into heat.

    SUMMARY OF THE INVENTION



    [0009] During proper operation of the aircraft, the power required for electrical devices is supplied by engine-driven generators. However, should it become necessary in this state to provide oxygen-depleted air and/or water with the assistance of a fuel cell system, there is no demand on the part of the voltage supply network for additional electrical power. Therefore, in order to operate the fuel cell system, an electrical energy converter, for example a heater, would have to be used to remove the electrical power. However, the problem here is that the resultant heat must also be removed.

    [0010] Therefore, the object of the invention is to provide a fuel cell system that, if needed, may provide larger quantities of inert gas in the quality required and/or water, without an electrical load itself converting just the electrical power provided by the fuel cell into heat and comprehensive measures being required to remove the resultant heat for this purpose.

    [0011] The object is achieved by an aircraft with the features in independent claim 1. Advantageous embodiments and further developments may be gleaned from the subclaims and following description.

    [0012] Proposed is an aircraft comprising a fuselage, at least one room formed therein, and a fuel cell system, the fuel cell system comprising- at least one fuel cell with a first inlet for supplying a fuel, a second inlet for supplying air, an outlet for removing exhaust air, and a voltage output,- an electrically drivable hydraulic pump, which is integrated into a hydraulic network of the aircraft, which hydraulic pump is connected with the voltage output of the at least one fuel cell,- a controllable hydraulic energy converter with variable operating behaviour , and- a control unit,wherein the hydraulic energy converter is set up to convert hydraulic power into heat in the hydraulic network,wherein the control unit is coupled with the at least one fuel cell, the electrically drivable hydraulic pump and the hydraulic energy converter, and set up to put the fuel cell followed by the hydraulic pump into operation, and to actuate the hydraulic energy converter in such a way as to achieve a sufficient electrical power output by the fuel cell, such that the fuel cell dispenses electrical power to the hydraulic pump to provide a prescribed volume flow of oxygen-depleted exhaust air to the outlet, and wherein the outlet is coupled with the at least one room, so as to inertize the at least one room or extinguish a fire developing therein.

    [0013] The term "at least one fuel cell" must be understood to mean that both individual fuel cells and a group of fuel cells may be used in the fuel cell system according to the invention. A group of fuel cells may be comprised of individual fuel cells connected with each other in parallel or serially, or take the form of fuel cell stacks (fuel cell stacks). In the latter case, shared inlets and lines for supplying and distributing fuel and oxidants may be used, which simultaneously facilitates shared cooling. In addition, the operation of several fuel cell stacks one next to the other may also not be ruled out.

    [0014] For example, the first inlet for supplying a fuel may be connected with an anode side of the at least one fuel cell, and absorb water, which is guided on the anode of the at least one fuel cell. The second outlet may be supplied with air as the oxidant, which stemmed from the environment of the fuel cell, an exhaust air line from the cabin of the aircraft, a recirculation line or an exhaust gas line of monuments inside of the aircraft fuselage. The oxidant is guided on the cathode side of the at least one fuel cell, which is separated from the anode side by an electrolyte. After the fuel and oxidant have been supplied, the provided electrical power is tapped to generate oxygen-depleted air on the cathode side, which then exits the at least one fuel cell through the outlet.

    [0015] The electrically drivable hydraulic pump may be designed as an additional, separate pump, which is electrically connected with the at least one fuel cell, and is then only operated when the fuel cell system is in operation. This eliminates the need for having to separate an already present hydraulic pump from an electrical network, and instead utilize the at least one fuel cell as its power supply, and following its operation, couple the hydraulic pump with the respective electrical network once more. However, it may also make sense to use an electrically drivable hydraulic pump that is already present in a hydraulic system.

    [0016] In order to electrically operate the hydraulic pump, the latter comprises an electric motor, which may be a direct current motor or an alternating current motor. Since the fuel cell delivers a DC voltage, utilizing an alternating current motor may require an inverter, which is placed between the at least one fuel cell and electric motor.

    [0017] The hydraulic pump may be an axial piston pump with swash plate, a vane pump, a gear pump, a screw spindle pump or a radial piston pump, with the axial piston pump in particular being suitable.

    [0018] The swash plate may comprise a constant or variable angle.

    [0019] A core idea of the invention involves using a hydraulic energy converter, which is arranged between a high-pressure side and low-pressure side of the hydraulic network, and does not perform any appreciable mechanical work. Rather, the percentage of hydraulic liquid flowing through the energy converter is heated, and cooled by corresponding coolers of the hydraulic network, or just by convection between the corresponding hydraulic lines and their respective environment. As a consequence, the realizable performance losses here lead to a high power output by the hydraulic pump, which in turn leads to a high electrical power output of the at least one fuel cell. This makes it possible to ensure the production of oxygen-depleted exhaust air and/or of water.

    [0020] The hydraulic energy converter is provided to absorb hydraulic power and generate only a negligible amount of mechanical power, or none at all, so that the hydraulic power is primarily converted into heat. The exhaust heat heats up the hydraulic fluid, which may be removed via already present cooling devices.

    [0021] The controllable operating behavior of the hydraulic energy converter may preferably be instigated by a control unit, for example which is also responsible for initiating, controlling and/or monitoring the operation of the at least one fuel cell. When commissioning the fuel cell system, the control unit could simultaneously or consecutively set the at least one fuel cell to a predetermined operational phase by opening the first inlet to supply the fuel, opening the second inlet to supply the oxidant, and establishing an electrical connection with the electrically drivable hydraulic pump, at the same time as the hydraulic energy converter. For example, the latter could be set so as to allow the hydraulic pump to start. With the hydraulic pump in operation, the operating behavior of the energy converter could then be influenced in such a way as to generate a higher hydraulic power loss, until the hydraulic pump requires the type of electrical power that is equivalent to the desired mass flow of water and/or oxygen-depleted air. The hydraulic energy converter may here encompass a second operational phase, for example.

    [0022] A special advantage to the fuel cell system according to the invention lies in the simple structural design and low system complexity. Even with a compact hydraulic pump, very high hydraulic power levels may be achieved, which result in a high electrical power consumption. As a consequence, the fuel cell system as a generator for oxygen-depleted air and/or water may be reliably operated continuously and at a high power.

    [0023] In an advantageous embodiment, the hydraulic energy converter comprises a flow screen with an adjustable opening cross section and an actuator that adjusts the opening cross section. The flow screen connects the high-pressure portion and low-pressure portion of the hydraulic network, and the hydraulic liquid flows through the screen at a rate depending on the open cross section and pressure difference, with a turbulence forming upstream and downstream from the opening edges of the opening cross section. The flow screen here creates a local flow resistance that abruptly narrows the line cross section, and in the process converts hydraulic power into heat. The operating behavior of flow screens is sufficiently known, and flow screens along with their adjustment mechanisms may be deemed sophisticated. As a consequence, the use of one or more flow screens connected in parallel or in series represents an especially simple approach toward realizing the energy converter that is reliable and safe.

    [0024] In a preferred embodiment, the energy converter is arranged downstream from a priority valve, and the other hydraulic load is overridingly supplied with hydraulic fluid. As a consequence, corresponding terminals for hydraulic loads are situated at locations of the hydraulic network that are farther away from the hydraulic pump, so that these loads are supplied overridingly with hydraulic fluid. The proper operation of especially safety-critical loads may thereby be ensured, so as not to detract from the safety of the aircraft. If the energy converter were located upstream from the other hydraulic loads, the concern would be that the latter will be deactivated as soon as the supply of safety-critical loads is placed in jeopardy, for example due to a complete blockage of an opening cross section or the like.

    [0025] The fuel cell system may further comprise a dispensing opening for selectively dispensing the generated water or generated oxygen-depleted exhaust air into the environment of the aircraft. The goal of this further development is to also be able to use the fuel cell system for preheating the hydraulic network, when there exists no demand for water or oxygen-depleted air. Only a brief operation of the fuel cell system might be required, potentially causing water and/or oxygen-depleted exhaust air to exit the aircraft. However, by coupling the electrically drivable pump with an electrical network on board the aircraft that delivers electrical power, the respective hydraulic network may be preheated even without the at least one fuel cell being in operation. For example, preheating a hydraulic network according to a similar scheme is known from EP 2 160 323 B1.

    [0026] It is generally conceivable for the generated water to also be routed on board the aircraft in a corresponding tank, from where it is used, for example, for a lavatory or to humidify processed air for the cabin of the aircraft.

    [0027] It is further also conceivable to store oxygen-depleted air in a pressure tank, so that, if necessary, as high a volume flow of oxygen-depleted air as possible may be routed into the room where a fire is to be extinguished.

    [0028] It is advantageous for the control unit to be coupled with the hydraulic energy converter, and set up to control the operating behavior of the hydraulic energy converter depending on the electrical power absorbed by the electrically drivable hydraulic pump. This may be accomplished by way of a functional correlation, in predetermined stages or through characteristic control.

    [0029] It is especially advantageous for a control unit, e.g., one corresponding to the control unit mentioned above, to be set up to initiate the operation of the fuel cell system to increase the temperature of the hydraulic network.

    [0030] It would be advantageous to monitor a temperature of the hydraulic network and, if the temperature drops below a predetermined value, initiate the operation of the fuel cell system to increase the temperature in the hydraulic network. The mentioned control unit could therefore be set up to correspondingly initiate the operation of the fuel cell system once a temperature has been found to drop below a predetermined value. However, the control unit could also be set up to only put the electrically drivable hydraulic pump into operation, thus rendering the operation of the at least one fuel cell unnecessary. This may be advantageous in particular when the control unit and/or electrically drivable hydraulic pump are not dedicated components of the fuel cell system, but rather are realized with components already present in an aircraft within the framework of a multifunctional approach.

    [0031] The system may further comprise at least one additional electrical load, which is connectable with the voltage output of the at least one fuel cell. This improves the possibility of providing a sink for electrical power, so that the operation of the fuel cell system will lead to the desired success. The electrical load may be whatever kind desired, and be realized by an actual effectively usable device or a device that exclusively serves to remove electrical power.

    [0032] In particular, the additional electrical load may be an energy converter, which converts electrical power or energy into another form of power or energy.

    [0033] It is especially advantageous for the additional electrical load to be a heater, which generates heat while in operation. The latter must correspondingly be dissipated into the environment.

    [0034] In particular if designed as a heater, the additional electrical load is especially preferably located in a ram air duct of the aircraft. As a result, air continuously streams around it, and comprises a low enough temperature to absorb heat. The ram air duct may be provided for any systems desired, for example to cool a heat exchanger of an air conditioning system, an oil cooler of an engine, a ram air duct for introducing fresh air in a venting system, or for other purposes.

    [0035] The additional electrical load may further be located in the ram air duct downstream from a heat exchanger. As a result, the thermal output by the heat exchanger may be ensured. This prevents any impairment to its operation, in particular due to an additional heat load in the ram air duct.

    [0036] The invention further relates to a method for operating a fuel cell system, which in particular involves the steps of coupling at least one fuel cell with a hydraulic pump, actuating a hydraulic energy converter arranged in a hydraulic network, and dispensing water and/or oxygen-depleted air through the at least one fuel cell. The method may further involve the step of operating an additional electrical load to increase the power output of the at least one fuel cell.

    [0037] In addition, the invention relates to an aircraft with a fuselage and at least one room formed therein, as well as a fuel cell system with the features mentioned above. This makes it possible to produce oxygen-depleted air, which may inertize the room or extinguish a fire developing therein.

    [0038] To this end, the electrically drivable hydraulic pump may be arranged in an emergency hydraulic network. The emergency hydraulic network does not necessarily have to be operated only in an emergency situation, but may also perform functions required for aircraft operation even with the aircraft in a normal state. In the event of an emergency, precisely this emergency hydraulic network may serve to perform primary, hydraulics-based functions.

    BRIEF DESCRIPTION OF THE FIGURES



    [0039] Additional features, advantages and possible applications of the present invention may be gleaned from the following description of exemplary embodiments and the figures. All described and/or graphically illustrated features here comprise the subject matter of the invention, whether taken in isolation or in any combination, even independently of their composition in the individual claims or back references thereto. Furthermore, identical reference numbers on the figures stand for the same or similar objects.

    Fig. 1 shows a fuel cell system in a block-based, schematic depiction.

    Fig. 2 shows an aircraft with a fuselage, a room created therein, and a fuel cell system in a schematic side view.


    DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS



    [0040] Fig. 1 shows a fuel cell system 2 with a fuel cell stack comprised of at least one fuel cell 4, which comprises a first inlet 6 for a fuel, a second inlet 8 for an oxidant, and an outlet 10 for exhaust air. Also present is a voltage output 12, which is connected both with an anode side 14 and a cathode side 16. The first inlet 6 is situated on the anode side 14, and delivers hydrogen or a hydrogen-containing gas to the fuel cell stack 4. While using a reformer or reactor for converting jet fuel into a hydrogen-containing gas might be sufficient for a hydrogen-containing gas, a sufficient volume flow of pure hydrogen may only be provided from a storage device. Aside from cryogenic storage technology, pressure accumulators and metal hydride accumulators are also possible. Air is passed through the second inlet 8. The reaction between the hydrogen and oxygen generates heat, electricity and oxygen-depleted air, as well as water, which is present in the oxygen-depleted exhaust air in particular as water vapor. If the fuel cell system is to serve exclusively for producing water, oxygen from an oxygen accumulator may also be used.

    [0041] Continuously implementing the fuel cell process requires that electrical power be tapped from the fuel cell stack 4. Provided in the fuel cell system 2 according to the invention for this purpose is an electrically drivable hydraulic pump 18, which comprises an electric motor 20 and a pump unit 22. For example, the latter may be an axial piston pump with a constant or variable angle of a swash plate. The pump unit 22 is connected with a hydraulic network 24, which incorporates hydraulic loads 26. The latter are connected with a high-pressure branch 28 and a low-pressure branch 30.

    [0042] Let it be noted in this conjunction that in particular single-aisle aircraft manufactured by AIRBUS have three hydraulic systems, which are designated as a green, yellow and blue system. While the green and yellow system are each supplied with pressure by engine-driven hydraulic pumps, the blue hydraulic system comprises an electrically drivable hydraulic pump along with a hydraulic pump driven by a ram air turbine (RAT, ram air turbine). While the hydraulic pump 18 may be integrated into one of the yellow or green hydraulic systems, it may be beneficial to integrate it into the blue hydraulic system, since the electrically drivable hydraulic pump present there may be coupled with the fuel cell stack 4. In other aircraft models, the hydraulic system designations may differ, and it is further possible to integrate or use an electrically drivable hydraulic pump in one of two primary hydraulic networks.

    [0043] In order to achieve a sufficient power output, use is made of a hydraulic energy converter 32, for example one designed as a flow screen, which comprises an actuator 34 for adjusting the opening cross section. In the case shown, the latter is downstream from a prioritization valve 36, which ensures that the hydraulic loads 26 are preferably supplied with hydraulic liquid and pressure. Reducing the flow cross section in the energy converter 32 makes it possible to increase the absorbed power of the pump unit 22, so that the electric motor 20 has to be supplied with more electrical power. This ensures that the fuel cell stack 4 provides enough oxygen-depleted exhaust air and/or water owing to the continuously high power demand. This would be impossible without a power output to the electric motor 20.

    [0044] In order to increase the electrical power to be applied even more, an additional electrical load 36 may be used, e.g., in the form of a heater, in a ram air duct 40 that may be sealed by way of a flap 41, for example. As an example, the additional electrical load 36 could be used downstream from a heat exchanger 42, which is situated in the ram air duct 40 for dissipating heat. The heat exchanger 42 is thus not impeded by the heat emitted by an additional electrical load 36. If the ram air duct 40 is a dedicated, separate ram air duct or does not have to be cooled by the heat exchanger 42, the ram air duct may be sealed by the flap 41 when the fuel cell 4 is not in operation.

    [0045] A control unit 38 is coupled with the at least one fuel cell 4, the electrically drivable hydraulic pump 18 and the hydraulic energy converter 32, and set up to put the fuel cell 4 followed by the hydraulic pump 18 into operation, in particular given a demand for oxygen-depleted air, and to actuate the hydraulic energy converter 32 in such a way as to achieve a sufficient electrical power output by the fuel cell 4. This makes it possible to put out a high volume flow of oxygen-depleted air having a high enough quality.

    [0046] All in all, the fuel cell system 2 may reliably provide oxygen-depleted exhaust air and/or water with no great outlay, without requiring any serious modifications to the aircraft.

    [0047] Fig. 2 presents a schematic side view of an aircraft 44, which comprises a fuselage 46 with a room 48 formed therein, for example one designed as a cargo hold. While the fuel cell system 2 is exemplarily arranged in an unpressurized area, this is in no way to be construed as a limitation. It may make just as much sense to arrange it in a pressurized area of the fuselage 46. The fuel cell system 2 may be coupled with the room 48, so that oxygen-depleted air may be introduced into the room 48 in the event of a fire or for inertization purposes.

    [0048] Let it further be noted that "comprise" does not preclude any other elements or steps, and that "a" or "an" does not rule out a plurality. In addition, let it be noted that features described with reference to one of the above exemplary embodiments may also be used in combination with other features of other exemplary embodiments described above. Reference numbers in the claims are not to be construed as a limitation.


    Claims

    1. An aircraft (44) comprising a fuselage (46), at least one room (48) formed therein, and a fuel cell system (2), the fuel cell system (2) comprising

    - at least one fuel cell (4) with a first inlet (6) for supplying a fuel, a second inlet (8) for supplying air, an outlet (10) for removing exhaust air, and a voltage output (12),

    - an electrically drivable hydraulic pump (18), which is integrated into a hydraulic network (24) of the aircraft, which hydraulic pump (18) is connected with the voltage output (12) of the at least one fuel cell (4),

    - a controllable hydraulic energy converter (32) with variable operating behavior, and

    - a control unit (38),

    wherein the hydraulic energy converter (32) is set up to convert hydraulic power into heat in the hydraulic network (24),
    wherein the control unit (38) is coupled with the at least one fuel cell (4), the electrically drivable hydraulic pump (18) and the hydraulic energy converter (32), and set up to put the fuel cell (4) followed by the hydraulic pump (18) into operation, and to actuate the hydraulic energy converter (32) in such a way as to achieve a sufficient electrical power output by the fuel cell (4), such that the fuel cell (4) dispenses electrical power to the hydraulic pump (18) to provide a prescribed volume flow of oxygen-depleted exhaust air to the outlet (10), and
    wherein the outlet (10) is coupled with the at least one room (48), so as to inertize the at least one room (48) or extinguish a fire developing therein.
     
    2. The aircraft (44) according to claim 1, wherein the hydraulic energy converter (32) comprises a flow screen (33) with an adjustable opening cross section and an actuator (34) that adjusts the opening cross section.
     
    3. The aircraft (44) according to claim 1, wherein the hydraulic energy converter (32) is arranged downstream from a priority valve (36), which overridingly supplies other hydraulic loads (26) with hydraulic fluid.
     
    4. The aircraft (44) according to one of the preceding claims, further comprising at least one dispensing opening for dispensing the generated water or generated oxygen-depleted exhaust air into the environment of the aircraft.
     
    5. The aircraft (44) according to one of the preceding claims, wherein the control unit (38) is set up to control the operating behavior of the hydraulic energy converter (32) depending on the electrical power absorbed by the electrically drivable hydraulic pump (18).
     
    6. The aircraft (44) according to claim 5, wherein the control unit (38) is set up to elevate the operation of the fuel cell system (4) to increase the temperature of the hydraulic fluid in the hydraulic network (24) if the temperature drops below a predetermined value.
     
    7. The aircraft (44) according to one of the preceding claims, further comprising at least one additional electrical load (36) that is connectable with the voltage output (12) of the at least one fuel cell.
     
    8. The aircraft (44) according to claim 7, wherein the additional electrical load (36) is an energy converter.
     
    9. The aircraft (44) according to claim 8, wherein the additional electrical load (36) is a heater.
     
    10. The aircraft (44) according to claim 8 or 9, wherein the additional electrical load (36) is located in a ram air duct (40) of the aircraft.
     
    11. The aircraft (44) according to claim 9, wherein the additional electrical load (36) is located in the ram air duct (40) downstream from a heat exchanger (42).
     
    12. A method for operating an aircraft comprising a fuel cell system (2), comprising the following steps:

    - coupling at least one fuel cell (4) with an electrically drivable hydraulic pump (18),

    - actuating a hydraulic energy converter (32) arranged in a hydraulic network (24) for converting hydraulic energy into heat, so that a predetermined electrical power is demanded and dispensed from the hydraulic pump (18), and

    - dispensing water and/or oxygen-depleted air through an outlet (10) of the at least one fuel cell (4), so as to inertize at least one room in the aircraft or extinguish a fire developing therein.


     
    13. The method according to claim 12, further comprising the following step:

    - operating an additional electrical load (36) to increase the power output of the at least one fuel cell (4).


     
    14. The aircraft of any of the previous claims, wherein the electrically drivable hydraulic pump (18) is arranged in an emergency hydraulic network.
     


    Ansprüche

    1. Flugzeug (44), das einen Rumpf (46), mindestens einen darin ausgebildeten Raum (48) und ein Brennstoffzellensystem (2) umfasst, wobei das Brennstoffzellensystem (2) umfasst

    - mindestens eine Brennstoffzelle (4) mit einem ersten Einlass (6) zum Zuführen eines Brennstoffs, einem zweiten Einlass (8) zum Zuführen von Luft, einem Auslass (10) zum Entfernen von Abluft und einer Spannungsausgabe (12),

    - eine elektrisch angetriebene Hydraulikpumpe (18), die in ein hydraulisches Netz (24) des Flugzeugs integriert ist, wobei die Hydraulikpumpe (18) mit der Spannungsausgabe (12) der mindestens einen Brennstoffzelle (4) verbunden ist,

    - einen steuerbaren hydraulischen Energiewandler (32) mit variablen Betriebsverhalten, und

    - eine Steuereinheit (38),

    wobei der hydraulische Energiewandler (32) eingestellt ist, um hydraulische Kraft in Hitze in dem hydraulischen Netz (24) umzuwandeln,
    wobei die Steuereinheit (38) mit der mindestens einen Brennstoffzelle (4), der elektrisch angetriebenen Hydraulikpumpe (18) und dem hydraulischen Energiewandler (32) gekoppelt ist und aufgebaut ist, um die Brennstoffzelle (4) gefolgt von der Hydraulikpumpe (18) in Betrieb zu versetzen und den hydraulischen Energiewandler (32) auf eine solche Weise zu betätigen, um eine ausreichende elektrische Leistungsausgabe durch die Brennstoffzelle (4) zu erzielen, so dass die Brennstoffzelle (4) elektrische Leistung an die Hydraulikpumpe (18) abgibt, um dem Auslass (10) eine festgelegte Volumenströmung von sauerstoffarmer Abluft bereitzustellen, und
    wobei der Auslass (10) mit dem mindestens einen Raum (48) gekoppelt ist, um so den mindestens einen Raum (48) zu inertisieren oder ein sich darin entwickelndes Feuer zu löschen.
     
    2. Flugzeug (44) nach Anspruch 1, wobei der hydraulische Energiewandler (32) einen Strömungsbildschirm (33) mit einem einstellbaren Öffnungsquerschnitt und einem Stellglied (34), das den Öffnungsquerschnitt einstellt, umfasst.
     
    3. Flugzeug (44) nach Anspruch 1, wobei der hydraulische Energiewandler (32) stromabwärts von einem Prioritätsventil (36) angeordnet ist, welches vorrangig andere hydraulische Lasten (26) mit Hydraulikfluid versorgt.
     
    4. Flugzeug (44) nach einem der vorhergehenden Ansprüche, ferner umfassend mindestens eine Abgabeöffnung zum Abgeben des erzeugten Wassers oder der erzeugten sauerstoffarmen Abluft in die Umgebung des Flugzeugs.
     
    5. Flugzeug (44) nach einem der vorhergehenden Ansprüche, wobei die Steuereinheit (38) aufgebaut ist, um das Betriebsverhalten des hydraulischen Energiewandlers (32) abhängig von der elektrischen Leistung, die von der elektrisch angetriebenen Hydraulikpumpe (18) absorbiert wird, zu steuern.
     
    6. Flugzeug (44) nach Anspruch 5, wobei die Steuereinheit (38) aufgebaut ist, um den Betrieb des Brennstoffzellensystems (4) zu erheben, um die Temperatur des Hydraulikfluids in dem hydraulischen Netz (24) zu erhöhen, wenn die Temperatur unterhalb eines vorbestimmten Werts fällt.
     
    7. Flugzeug (44) nach einem der vorhergehenden Ansprüche, ferner umfassend mindestens eine zusätzliche elektrische Last (36), die mit der Spannungsausgabe (12) der mindestens einen Brennstoffzelle verbunden werden kann.
     
    8. Flugzeug (44) nach Anspruch 7, wobei die zusätzliche elektrische Last (36) ein Energiewandler ist.
     
    9. Flugzeug (44) nach Anspruch 8, wobei die zusätzliche elektrische Last (36) ein Heizkörper ist.
     
    10. Flugzeug (44) nach Anspruch 8 oder 9, wobei die zusätzliche elektrische Last (36) sich in einem Stauluftkanal (40) des Flugzeugs befindet.
     
    11. Flugzeug (44) nach Anspruch 9, wobei die zusätzliche elektrische Last (36) sich in dem Stauluftkanal (40) stromabwärts von einem Wärmetauscher (42) befindet.
     
    12. Verfahren zum Betreiben eines Flugzeugs, das ein Brennstoffzellensystem (2) umfasst, die folgenden Schritte umfassend:

    - Koppeln mindestens einer Brennstoffzelle (4) mit einer elektrisch angetriebenen Hydraulikpumpe (18),

    - Betätigen eines hydraulischen Energiewandlers (32), der in einem hydraulischen Netz (24) zum Umwandeln von hydraulischer Energie in Hitze angeordnet ist, so dass eine vorbestimmte elektrische Leistung von der Hydraulikpumpe (18) angefordert und abgegeben wird, und

    - Abgeben von Wasser und/oder sauerstoffarmer Luft durch einen Auslass (10) der mindestens einen Brennstoffzelle (4), um so mindestens einen Raum in dem Flugzeug zu inertisieren oder ein sich darin entwickelndes Feuer zu löschen.


     
    13. Verfahren nach Anspruch 12, ferner umfassend den folgenden Schritt:

    - Betreiben einer zusätzlichen elektrischen Last (36), um die Leistungsausgabe der mindestens einen Brennstoffzelle (4) zu erhöhen.


     
    14. Flugzeug nach einem der vorhergehenden Ansprüche, wobei die elektrisch angetriebene Hydraulikpumpe (18) in einem hydraulischen Notfallnetz angeordnet ist.
     


    Revendications

    1. Aéronef (44) comprenant un fuselage (46), au moins une chambre (48) formée dans celui-ci et un système de piles à combustible (2), le système de piles à combustible (2) comprenant

    - au moins une pile à combustible (4) avec une première entrée (6) pour fournir un combustible, une seconde entrée (8) pour fournir de l'air, une sortie (10) pour évacuer l'air d'échappement et une sortie de tension (12),

    - une pompe hydraulique actionnable électriquement (18), intégrée dans un réseau hydraulique (24) de l'aéronef, cette pompe hydraulique (18) étant reliée à la sortie de tension (12) de la ou des piles à combustible (4),

    - un convertisseur d'énergie hydraulique contrôlable (32) à comportement variable, et

    - une unité de commande (38),

    dans lequel le convertisseur d'énergie hydraulique (32) est configuré pour convertir l'énergie hydraulique en chaleur dans le réseau hydraulique (24),
    dans lequel l'unité de commande (38) est couplée à la ou aux piles à combustible (4), à la pompe hydraulique pouvant être actionnée électriquement (18) et au convertisseur d'énergie hydraulique (32), et mise en place pour mettre en service la pile à combustible (4) suivie de la pompe hydraulique (18) et actionner le convertisseur d'énergie hydraulique (32) de manière à obtenir une puissance électrique suffisante à la sortie de la pile à combustible (4), de telle sorte que la pile à combustible (4) distribue de l'énergie électrique à la pompe hydraulique (18) pour fournir un débit volumique prédéterminé d'air d'échappement appauvri en oxygène à la sortie (10), et
    dans lequel la sortie (10) est couplée à la ou aux chambres (48), de manière à rendre inertes la ou les chambres (48) ou à éteindre un feu s'y développant.
     
    2. Aéronef (44) selon la revendication 1, dans lequel le convertisseur d'énergie hydraulique (32) comprend un écran d'écoulement (33) ayant une section transversale d'ouverture réglable et un actionneur (34) qui règle la section transversale d'ouverture.
     
    3. Aéronef (44) selon la revendication 1, dans lequel le convertisseur d'énergie hydraulique (32) est disposé en aval d'une vanne de priorité (36), qui alimente de manière prédominante d'autres charges hydrauliques (26) en fluide hydraulique.
     
    4. Aéronef (44) selon l'une quelconque des revendications précédentes, comprenant en outre au moins une ouverture de distribution pour distribuer l'eau générée ou l'air d'échappement appauvri en oxygène généré dans l'environnement de l'aéronef.
     
    5. Aéronef (44) selon l'une quelconque des revendications précédentes, dans lequel l'unité de commande (38) est configurée pour contrôler le comportement en fonctionnement du convertisseur d'énergie hydraulique (32) en fonction de la puissance électrique absorbée par la pompe hydraulique pouvant être actionnée électriquement (18).
     
    6. Aéronef (44) selon la revendication 5, dans lequel l'unité de commande (38) est conçue pour élever le fonctionnement du système de piles à combustible (4) afin d'augmenter la température du fluide hydraulique dans le réseau hydraulique (24) si la température chute en dessous d'une valeur prédéterminée.
     
    7. Aéronef (44) selon l'une quelconque des revendications précédentes, comprenant en outre au moins une charge électrique supplémentaire (36) pouvant être connectée à la sortie de tension (12) de la ou des piles à combustible.
     
    8. Aéronef (44) selon la revendication 7, dans lequel la charge électrique supplémentaire (36) est un convertisseur d'énergie.
     
    9. Aéronef (44) selon la revendication 8, dans lequel la charge électrique supplémentaire (36) est un dispositif de chauffage.
     
    10. Aéronef (44) selon la revendication 8 ou 9, dans lequel la charge électrique supplémentaire (36) est située dans un conduit d'air dynamique (40) de l'aéronef.
     
    11. Aéronef (44) selon la revendication 9, dans lequel la charge électrique supplémentaire (36) est située dans le conduit d'air dynamique (40) en aval d'un échangeur de chaleur (42).
     
    12. Procédé pour faire fonctionner un aéronef comprenant un système de piles à combustible (2), comprenant les étapes consistant à :

    - coupler au moins une pile à combustible (4) avec une pompe hydraulique actionnée électriquement (18),

    - actionner un convertisseur d'énergie hydraulique (32) disposé dans un réseau hydraulique (24) pour convertir de l'énergie hydraulique en chaleur, de sorte qu'une puissance électrique prédéterminée soit demandée et distribuée à partir de la pompe hydraulique (18), et

    - distribuer de l'eau et/ou de l'air appauvri en oxygène à travers une sortie (10) de la ou des piles à combustible (4), de manière à rendre inerte au moins une chambre de l'aéronef ou éteindre un incendie s'y développant.


     
    13. Procédé selon la revendication 12, comprenant en outre l'étape suivante :

    - commande d'une charge électrique supplémentaire (36) pour augmenter la puissance de sortie de la ou des piles à combustible (4).


     
    14. Aéronef selon l'une quelconque des revendications précédentes, dans lequel la pompe hydraulique à actionnement électrique (18) est disposée dans un réseau hydraulique de secours.
     




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    REFERENCES CITED IN THE DESCRIPTION



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    Patent documents cited in the description