Aircraft and method for operating an aircraft engine

Abstract

The invention relates to an aircraft and a method for operating an aircraft engine, the aircraft comprising a combustion engine having a combustion chamber and an injection device for injecting fuel into the combustion chamber, the aircraft further comprising an air separation device adapted to separate air into an oxygen-rich gas mixture and a nitrogen-rich gas mixture, the oxygen-rich gas mixture being injected into the combustion chamber together with the fuel, while the nitrogen-rich gas mixture is used to inert at least some parts of the aircraft in the environment of the combustion engine.

Description

Technical Field

[0001] This invention relates to aircraft inerting systems. More specifically, it relates to aircraft including an air separation device adapted to provide nitrogen-rich air to inertate certain areas of the aircraft. Background Technology

[0002] An important aspect of aircraft safety includes inerting hazardous areas of the aircraft. This is especially true in aircraft that include combustion engines, where fuel systems and fuel tanks can be inerted to ensure low oxygen levels, thereby preventing fires or explosions.

[0003] US 9272790 discloses an aircraft with an air separation module for producing a nitrogen-rich supply to a fuel tank. This allows the fuel tank to be inerted by significantly reducing the oxygen content of the gas mixture surrounding the fuel. This document provides insights into temperature control of the air supplied to the air separation module to extend its operational life.

[0004] This aircraft does not optimize the use and weight of its onboard inerting system. Furthermore, some areas of the aircraft may not have been inerted using the system according to this document.

[0005] In addition, fuel efficiency is an important criterion in aircraft design because low-fuel-consumption aircraft have a smaller environmental impact and allow for optimization of their operating costs.

[0006] US 5131225 provides a system in which a large amount of oxygen is generated by a ceramic air separator, cooled, and stored on the aircraft to start air-breathing engines at high altitudes in emergency situations. However, such systems are particularly heavy and only cover very rare emergency situations, thus having a significant impact on the fuel efficiency of aircraft equipped with such systems.

[0007] In addition, there is a need for aircraft that are highly efficient and have low pollutant emissions, especially nitrogen oxides (NOx).

[0008] This means that in the future, all of an aircraft's onboard power could be used during flight, unlike current commercial aircraft. Current aircraft have a much higher power generation potential than they actually use in flight. Specifically, current commercial aircraft have auxiliary power units (APUs) that are only used on the ground or as safety power generators in certain emergency situations. This optimization of onboard power generation means that all engines can be used at different stages of flight.

[0009] WO2015050601 describes a fuel system for a gas turbine engine, the fuel system including an injector configured to inject fuel and air into a combustor of the gas turbine engine. In a first embodiment, the fuel system further includes an air separation module configured to supply oxygen-enriched air to the combustor via the injector for combustion. The document also describes an air separation module configured to pump nitrogen-enriched air into a fuel canister for inerting by reducing the flammability of fuel vapors within the fuel canister.

[0010] Furthermore, as the aerospace industry explores the use of hydrogen as an alternative fuel, engine systems must be inspected to ensure safety and efficiency when hydrogen is used as fuel.

[0011] The use of hydrogen, especially in areas where aircraft have not been used continuously during flight until now, necessitates new areas for inerting aircraft, as well as new systems, operating methods, and aircraft configurations that can meet aviation requirements in terms of safety and fuel efficiency. Summary of the Invention

[0012] The present invention aims to provide an aircraft inerting system, and more generally, an aircraft, and a method for operating the aircraft inerting system, which provides solutions to these problems.

[0013] The present invention aims to provide a system and method that provides a high level of security.

[0014] The present invention aims to provide an aircraft with high fuel combustion efficiency.

[0015] The present invention also aims to provide an aircraft with very low levels of nitrogen oxide emissions.

[0016] This invention proposes an aircraft, the aircraft comprising:

[0017] - A combustion engine, said combustion engine comprising:

[0018] Combustion chamber,

[0019] • An injection device, comprising a fuel inlet and adapted to inject fuel into the combustion chamber when fuel is supplied at the fuel inlet of the injection device.

[0020] - An air separation device, the air separation device comprising:

[0021] • An air intake port, adapted to take in a raw gas mixture comprising at least oxygen and nitrogen.

[0022] • Oxygen outlet: The air separator is adapted to output an oxygen-enriched gas mixture at the oxygen outlet, the oxygen-enriched gas mixture comprising an oxygen content higher than that of the original gas mixture when it is introduced at the air inlet.

[0023] • Nitrogen outlet: The air separation device is adapted to output a nitrogen-rich gas mixture at the nitrogen outlet, the nitrogen-rich gas mixture comprising a higher nitrogen content than the original gas mixture introduced at the air inlet.

[0024] Its features are:

[0025] - The nitrogen outlet of the air separation device is hydraulically connected to the inerting circuit.

[0026] - The oxygen output port of the air separation device is hydraulically connected to the injection device.

[0027] Throughout this text, the term "combustion engine" refers to an internal combustion engine in which the chemical energy released by the oxidation of fuel or a fuel mixture with oxygen is converted into mechanical energy.

[0028] An air separation device is adapted to provide an oxygen-enriched gas mixture stream and a nitrogen-enriched gas mixture stream when it receives a raw gas mixture (such as air) comprising at least nitrogen and oxygen at its inlet. The air separation device may be of the type described, for example, in FR 3011484.

[0029] The original gas mixture can be air, and its composition may vary between low and high altitudes, between atmospheric composition and the cabin air that is inhaled or recirculated, etc.

[0030] The injection device includes a fuel inlet adapted to receive fuel and a fuel outlet adapted to supply fuel in the combustion chamber. The injection device can be controlled by a computing unit, such as a controller.

[0031] In the aircraft according to the invention, both a nitrogen-rich gas mixture and an oxygen-rich gas mixture produced by the air separation device are used by the aircraft, thereby optimizing the weight of the air separation device. More specifically, nitrogen is used to inerte certain areas of the aircraft, while oxygen is used to improve combustion in the combustion engine.

[0032] Injecting an oxygen-enriched gas mixture into a combustion engine, particularly via an injection device, allows for a higher oxygen ratio in certain areas of the combustion chamber. Specifically, in turbine engines, only about 20%-30% of the engine's total oxygen intake is used for combustion. Only about 10% burns in the first combustion stage, at the head of the main combustion zone, where temperatures are highest and NOx formation is also highest. By introducing an oxygen-enriched gas mixture with the fuel, the oxygen ratio in the first combustion zone of the engine of the aircraft according to the invention is significantly higher, resulting in improved combustion and a reduction in nitrogen levels. Therefore, the present invention reduces NOx formation due to the presence of nitrogen in the first stage of fuel oxidation (where temperatures in the combustion chamber are highest).

[0033] Furthermore, by injecting an oxygen-rich gas mixture into the combustion chamber, the engine's direct intake of atmospheric air can be slightly reduced, making it possible to consider reducing the engine size and thus providing a lighter aircraft.

[0034] Therefore, this invention proposes a highly efficient aircraft with very low NOx emission levels.

[0035] The inerting circuit can be hydraulically connected to the aircraft's engine compartment. The engine compartment houses the combustion engine.

[0036] Combustion engines can be auxiliary power units.

[0037] The engine compartment can be a compartment located in the rear fuselage of the aircraft.

[0038] The aircraft according to the present invention allows for full utilization of the auxiliary power unit and optimization of its efficiency.

[0039] The inerting circuit can be hydraulically connected to the upper part of the engine compartment.

[0040] Injecting a nitrogen-rich gas mixture into the upper part of the engine compartment allows for dedicated exhaust of this portion of the engine compartment. This prevents the accumulation of light gases, such as hydrogen, in the upper part of the engine compartment. In fact, if the auxiliary power unit is at least partially supplied with hydrogen, inerting the engine compartment or at least some areas of the engine compartment is highly beneficial to the safety of the aircraft.

[0041] Therefore, the air separator can be a dedicated device for the auxiliary power unit. The air separator can provide a nitrogen-rich gas mixture for inerting only the engine compartment. The air separator can also provide an oxygen-rich gas mixture for injection only into the auxiliary power unit's combustion chamber.

[0042] The aircraft may include a nitrogen-rich gas mixture loop connected to the nitrogen outlet of an air separation unit. The nitrogen-rich gas mixture can be used to dilute any fuel vapors in areas of the aircraft that may be ignited by other components such as heat sources.

[0043] A nitrogen-enriched gas mixture circuit may include one or more nitrogen nozzles for injecting a nitrogen-enriched gas mixture at one or more specific locations. In particular, locations with overheating or ignition risks can be identified during the design phase and equipped with such nitrogen nozzles for injecting nitrogen during nominal operation of the aircraft or engine, or at any time when ordered. Targeted injection of a nitrogen-enriched gas mixture onto hot surfaces allows for cooling of these surfaces, eliminating the risk of ignition due to their very low oxygen levels. The oxygen level of the nitrogen-enriched gas mixture can advantageously be below 8%, particularly approximately or below 4%.

[0044] Nitrogen-rich gas mixtures can also be used to surround components with a high risk of ignition with an inert volume of nitrogen-rich gas mixture.

[0045] It can control the nitrogen nozzle, or it can control the valve in the circuit leading to the valve.

[0046] Therefore, in the method according to the invention, nitrogen is injected at the target area of ​​the aircraft, more specifically at the target area in the engine compartment. The target area is a specific local area that can be determined to have a high risk of leakage, or a high risk of fire or explosion in the presence of fuel in its vicinity.

[0047] A nitrogen-enriched gas mixture can also be injected to extinguish a fire or combustion engine when a risk is detected. In the event of a fire, the nitrogen-enriched gas mixture stream can, for example, be directed entirely to the fire area or the entire engine compartment.

[0048] The aircraft may further include a nitrogen-enriched gas mixture tank, which is hydraulically connected to the nitrogen outlet of an air separator to form a nitrogen-enriched gas mixture reserve for emergency use. Therefore, a large quantity of the nitrogen-enriched gas mixture can be released to prevent or extinguish a fire.

[0049] Using nitrogen-rich gas mixtures to limit flammability and / or extinguish fires in certain areas can reduce the need for onboard fire suppression equipment, thereby further reducing the weight of the aircraft.

[0050] The inerting circuit is hydraulically connected to a peripheral channel surrounding the fuel line. This peripheral channel can also be referred to as the "outer wall" surrounding the line. This achieves inerting of the fuel line. This feature of the invention is particularly relevant to light fuels such as hydrogen. In fact, hydrogen has a very small molecular size. Therefore, fuel lines containing hydrogen may be more prone to leakage, seepage, or diffusion.

[0051] The outer channel of the tube is filled with an inert gas, such as a nitrogen-rich gas mixture, which eliminates any danger caused by this property of hydrogen.

[0052] In the method according to the invention, at least a portion of the nitrogen-rich gas mixture is guided around the fuel pipe.

[0053] The nitrogen-rich gas mixture can therefore be maintained in the peripheral channel. This nitrogen-rich gas mixture can then be injected into the atmosphere outside the aircraft, thus expelling any fuel vapors. Therefore, the inerting circuit, including at least a portion of the peripheral channel, can have an outlet facing outwards from the aircraft. Any fuel leaking from the fuel line into its peripheral channel can therefore be safely contained and discharged outside the aircraft.

[0054] The air separator's intake can be hydraulically connected to the cabin air.

[0055] One or more hydraulic devices (such as pumps, valves, etc.) may be located on the cabin air circuit between the passenger cabin air and the intake.

[0056] Air separation devices are sensitive to ozone present in the upper atmosphere. This is why air separation devices specifically designed for inerted fuel tanks are typically associated with ozone converters. Since cabin air already removes ozone from the air, the air separation device of this invention does not need to be associated with an ozone converter. Therefore, the complexity and weight of the aircraft according to this invention are kept to a minimum.

[0057] Alternatively or in combination, in some embodiments, the intake of the air separator may be hydraulically connected to the atmosphere, particularly at low altitudes.

[0058] One or more hydraulic devices (such as pumps, valves, etc.) may be located in the air circuit between the raw air source (such as the engine compartment) and the intake of the air separator. The temperature of the raw air may also be adjusted to optimize the function and operational life of the air separator.

[0059] The aircraft may include an engine controller adapted to control at least one of the following streams: a raw gas mixture stream, an oxygen-enriched gas mixture stream, a nitrogen-enriched gas mixture stream, and a fuel stream for the combustion engine.

[0060] The controller can be any type of processing device.

[0061] The controller can control one or more of the raw gas mixture stream, the nitrogen-enriched gas mixture stream, or the oxygen-enriched gas mixture stream, allowing the controller to adjust the injection of each gas stream to suit engine operation. As described regarding the use of nitrogen-enriched gas mixtures in emergency situations or when risks are identified, the controller can control the nitrogen-enriched gas mixture stream to adapt the use of the nitrogen-enriched gas mixture to that situation.

[0062] The controller can adjust the amount of oxygen-enriched gas mixture injected into the combustion engine in the same way.

[0063] The hydraulic circuit between the oxygen outlet of the air separator and the injection device includes a pump.

[0064] The pump is adapted to increase the pressure of the oxygen-enriched gas mixture.

[0065] More specifically, the pump is placed on the hydraulic circuit between the oxygen outlet of the air separator and the mixing chamber or premixer, so that the oxygen-enriched gas mixture is injected into the premixer at a higher pressure.

[0066] The fuel can be hydrogen.

[0067] The fuel inlet of the injection device can be adapted to receive hydrogen.

[0068] Hydrogen oxidation primarily releases water and NOx. By removing nitrogen from the first combustion stage (i.e., by injecting an oxygen-enriched gas mixture from the air separator into a combustion chamber containing hydrogen), the inventors realized that NOx generation in hydrogen fuel engines could be reduced to almost zero.

[0069] The injection device can be adapted to inject a mixture of oxygen-enriched gas and fuel into the area of ​​the combustion chamber where fuel combustion primarily occurs.

[0070] The oxygen-enriched gas mixture burns only in the main combustion zone of the combustion chamber, the region with the highest temperature where most of the combustion between fuel and oxygen occurs. This region of the combustion chamber is where the presence of nitrogen is most needed to be avoided to reduce NOx formation. The inventors recognized that it was not necessary to simply inject oxygen into the combustion chamber to drastically reduce the amount of NOx generated; rather, this was achieved by injecting an oxygen-enriched gas mixture into the target region of the combustion chamber while the rest of the engine remained supplied with air.

[0071] Therefore, the air separator does not need to be large in size and mass, because it does not need to produce a large amount of oxygen-enriched gas mixture to supply the entire engine, but only to supply a small portion of the total oxygen intake to the engine.

[0072] The aircraft may further include a premixer, which:

[0073] -Including an oxygen inlet adapted to receive a stream of oxygen-enriched gas mixture.

[0074] -Including a fuel inlet adapted to receive fuel flow,

[0075] - It is adapted to mix the fuel and the oxygen-enriched gas mixture when fuel is introduced at its fuel inlet and an oxygen-enriched gas mixture is introduced at its oxygen inlet.

[0076] -Including an output port adapted to output a mixture of fuel and oxygen-enriched gas.

[0077] The premixer includes a mixing chamber in which fuel and an oxygen-enriched gas mixture are mixed when fuel is introduced at the fuel inlet of the premixer and an oxygen-enriched gas mixture is introduced at the oxygen inlet of the premixer.

[0078] The fuel inlet is hydraulically connected to a fuel source, such as a fuel tank, via a fuel circuit and a pump.

[0079] The output port of the premixer is hydraulically connected to the injection device.

[0080] The nitrogen outlet of the air separator can be hydraulically connected to the combustion chamber via a controlled safety valve. The combustion engine can be shut down by introducing a nitrogen-rich gas mixture into the combustion chamber instead of the fuel stream.

[0081] The controlled safety valve is closed during normal use. However, in an emergency, a nitrogen-rich gas mixture can be injected directly into the engine to extinguish any combustion and bring the engine to a rapid stop.

[0082] Similarly, the oxygen outlet of the air separator is hydraulically connected to the combustion chamber via a controlled valve that is open during nominal operation but can be closed in an emergency, allowing the supply of an oxygen-enriched gas mixture to the engine to be cut off in an emergency.

[0083] The aircraft may include additional valves to control the flow of nitrogen-enriched gas mixtures and / or oxygen-enriched gas mixtures. For example, a nitrogen-enriched gas mixture flow can also be used to inertate and vent fuel lines to ensure no fuel remains in the fuel lines. This can be particularly advantageous in fuel lines leading to the combustion chamber of a combustion engine. More specifically, venting the fuel lines may be necessary for light fuels such as hydrogen, as hydrogen could otherwise leak through the lines during extended periods of aircraft inactivity, posing a risk.

[0084] Therefore, before the engine stops, a nitrogen-rich gas mixture can be injected relatively upwards into the main fuel line leading to the engine to ensure that any fuel in the line is replaced by the nitrogen-rich gas mixture and to ensure that no fuel remains in the line when the engine shuts down due to flameout. This provides a safe shutdown phase for the engine, and subsequent safe operation within the engine compartment.

[0085] The invention also extends to a method for operating an aircraft engine, wherein:

[0086] - An oxygen-enriched gas mixture and a nitrogen-enriched gas mixture are generated from the air stream using an air separation device.

[0087] - An oxygen-enriched gas mixture is injected into the combustion chamber along with the fuel via an injection device.

[0088] The nitrogen-rich gas mixture is injected into the inerting circuit.

[0089] The method according to the invention allows for the operation of aircraft, particularly the auxiliary power unit, with high efficiency, low or no NOx emissions, and very high safety.

[0090] The invention also extends to other possible combinations of the features described in the foregoing description and the following description with reference to the accompanying drawings. In particular, the invention extends to methods including the features described with respect to aircraft; the invention extends to aircraft including the features described with respect to methods. Attached Figure Description

[0091] Some specific exemplary embodiments and aspects of the invention are described in the following description with reference to the accompanying drawings.

[0092] Figure 1 This is a schematic representation of an aircraft according to the invention, which includes a rear fuselage section having an engine compartment housing a combustion engine and an air separation device.

[0093] Figure 2 This is a schematic representation of the engine compartment of an aircraft according to the present invention.

[0094] Figure 3 This is a schematic representation of the aircraft system according to the present invention. Detailed Implementation

[0095] exist Figure 1 The image shows aircraft 1. The aircraft includes a rear fuselage section 2 in which a combustion engine 38 is mounted, more specifically, an auxiliary power unit. The auxiliary power unit is mounted in the engine compartment along with an air separation device.

[0096] exist Figure 2In the middle, it indicates that according to Figure 1 The engine compartment 34 houses the auxiliary power unit engine 38. The engine comprises various parts, including: a compressor 28 for taking in and compressing atmospheric air 37; a combustion chamber 27 for fuel oxidation; a turbine 29 driven by gases formed during combustion; and an exhaust system for discharging combustion exhaust gases into the atmosphere.

[0097] The engine compartment also houses a safety and efficiency device 11 according to the invention. The safety and efficiency device 11 includes at least one air separation device. The safety and efficiency device 11 draws in a fuel stream 24 from a fuel source (e.g., a fuel canister) and a raw gas mixture stream from an air source (e.g., cabin air 31). One or more air separation devices included in the safety and efficiency device 11 separate the air stream into an oxygen-enriched gas mixture stream and a nitrogen-enriched gas mixture stream. The safety and efficiency device 11 also mixes the fuel with the oxygen-enriched gas mixture to obtain a mixture that can be supplied to the injection device 12 of the combustion chamber 27.

[0098] In other embodiments of the invention, some portions of the safety and efficiency device 11 may be located outside the engine compartment. In particular, the air separation device may be installed outside the engine compartment.

[0099] Figure 3 This safety and efficiency device 11 is illustrated in more detail.

[0100] In this embodiment, the safety and efficiency device 11 includes an air separation device 18. The air separation device 18 receives cabin air at an intake. The cabin air is compressed by a compressor 35 to supply the air separation device 18 at a controlled pressure. The air separation device is adapted to separate the cabin air flow received at its intake into an oxygen-enriched gas mixture flow 26 and a nitrogen-enriched gas mixture flow 19 at an oxygen outlet. The air separation device 18 may be, for example, of the type comprising a hollow fiber membrane, which allows oxygen to permeate through its walls, while nitrogen cannot permeate through the walls and thus flows downward along the hollow fiber pores.

[0101] The oxygen-enriched gas mixture stream 26 is directed to pump 36, which is adapted to pressurize the oxygen-enriched gas mixture stream at a controlled pressure to supply it to premixer 13. Premixer 13 also receives fuel from fuel stream line 24. Premixer 13 includes a mixing chamber adapted to mix the oxygen-enriched gas mixture and fuel. The outlet of premixer 13 is connected to the inlet of injection device 12, allowing the fuel-oxygen-enriched gas mixture to be directed to injection device 12. Injection device 12 is adapted and installed to inject the fuel-oxygen-enriched gas mixture directly into the main zone 32 of combustion chamber 27. In the main zone 32 of combustion chamber, combustion occurs between fuel and oxygen, and this is where the highest temperatures are reached. In practice, additional air drawn from the atmosphere and compressed by compressor 28 of the turbine engine is injected into the main zone 32 and secondary zone 33. The fuel-oxygen combustion mixture moves towards the turbine from the main zone to the secondary zone and then out to the turbine. Therefore, the temperature in the secondary zone 33 of combustion chamber 27 is lower than that in the main zone 32. The injection of fuel and oxygen-enriched air into the head of the main zone via the injection device 12 provides a very pure mixture with low nitrogen levels, thereby significantly reducing NOx byproducts during combustion.

[0102] Before being introduced into the premixer 13, the fuel is extracted from a tank and introduced into the premixer 13 through a fuel pipe 16. The fuel pipe 16 may include double walls forming a peripheral channel 17 surrounding the fuel pipe 16. Figure 3 The image shows only a portion of the double-walled fuel pipe 16. However, this fuel pipe can be used on any pipe section to transport fuel or a mixture of fuels.

[0103] exist Figure 3 In the illustrated embodiment, the nitrogen-rich gas mixture stream 19 is separated into multiple nitrogen-rich gas mixture streams. A first nitrogen-rich gas mixture stream 20 is directed toward a peripheral channel 17 surrounding the fuel pipe 16. Therefore, any fuel vapor generated by permeation or leakage through the wall of the pipe 16 is not only discharged by the nitrogen-rich gas mixture stream but is also inerted by the high nitrogen content of the nitrogen-rich gas mixture. The nitrogen-rich gas mixture stream can then be discharged into the atmosphere outside the aircraft, for example, through an exhaust port.

[0104] The second nitrogen-rich gas mixture stream 21 is directed toward a controlled safety valve or fuel flow cut-off valve 23. This fuel flow cut-off valve 23 allows the fuel supply from the fuel tank to the premixer 13 to be cut off. Additionally, this fuel flow cut-off valve 23 allows the nitrogen-rich gas mixture stream 21, instead of fuel, to be injected into the fuel line 16, for example, the nitrogen-rich gas mixture stream flowing toward the premixer 13, and then toward the combustion chamber 27. When the nitrogen-rich gas mixture reaches the combustion chamber, combustion is extinguished, thereby achieving a safe shutdown of the turbine engine.

[0105] Furthermore, when the engine stops by shutting off, there is no fuel in the pipe 16 between the fuel flow cut-off valve 23 and the combustion chamber, and it is inertized by the nitrogen-rich gas mixture flow 21.

[0106] When the fuel flow cut-off valve 23 is closed to fuel and open to the nitrogen-rich gas mixture, another cut-off valve 14 can close the oxygen-rich gas mixture flow to the premixer 13, so that the premixer supplies the nitrogen-rich gas mixture only to the injection system and then to the combustion chamber.

[0107] The third nitrogen-rich gas mixture stream 22 is guided to a specific predetermined area in the engine compartment. Figure 3 (Not shown in detail), such as hot parts that need cooling to mitigate the risk of ignition, areas where fuel or other flammable products (such as lubricating oil) may leak and must be inerted. The third nitrogen-rich gas mixture stream 22 can also be directed toward the upper part of the engine compartment for exhaust. This is particularly advantageous in the case of fuels or combustibles that are lighter than air (such as hydrogen). Thus, the upper part of the engine compartment 34 can be inerted and exhausted by the nitrogen-rich gas mixture stream 22.

[0108] Figures 1 to 3 The presented aircraft example also includes an auxiliary power unit fuel system 15. Fuel system 15 in... Figure 3 Not shown in detail. The auxiliary power unit fuel system 15 is designed to supply fuel to the auxiliary power unit at any ambient temperature, pressure, or altitude within the aircraft's operating range. The auxiliary power unit fuel system 15 includes: a fuel flow filter, a fuel pump, a pressure regulator, a fuel shut-off valve, a fuel control unit, and several sensors (such as temperature sensors, pressure sensors, etc.). The auxiliary power unit fuel system is adapted to operate fuels containing ice at cryogenic temperatures, fuels containing additives, and contaminants.

[0109] Figures 1 to 3 The presented aircraft example also includes a controller 39. The controller 39 is adapted to control the oxygen-enriched gas mixture flow 26 by controlling the oxygen-enriched gas mixture pump 36. The controller 39 is also adapted to control the fuel flow 24 for the combustion engine 38 by controlling the fuel system 15. The controller 39 can also control the premixer 13 to control the mixing percentage of the fuel and oxygen-enriched gas mixture.

[0110] In other embodiments of the invention, the controller 39 may also be adapted to control the compressor 35 to control the air supply to the air separator 18. The controller may also be adapted to control the fuel cut-off valve 23 and / or the oxygen-enriched gas mixture cut-off valve 14.

[0111] This invention is not limited to the specific embodiments disclosed herein as examples. The invention also covers other embodiments not explicitly described herein, which may include different combinations of the features described herein.

Claims

1. An aircraft (1), said aircraft comprising: - Combustion engine (38), said combustion engine includes - Combustion chamber (27). - An injection device (12), the injection device including a fuel inlet and adapted to inject fuel into the combustion chamber when fuel is supplied at the fuel inlet of the injection device. - Air separation device (18), the air separation device comprising: • Air intake port, which is adapted to take in a raw gas mixture comprising at least oxygen and nitrogen (31). • Oxygen outlet, the air separator (18) is adapted to output an oxygen-enriched gas mixture (26) at the oxygen outlet, the oxygen-enriched gas mixture comprising an oxygen content higher than that of the original gas mixture (31) when it is introduced at the air inlet, and • Nitrogen outlet, the air separation device (18) is adapted to output a nitrogen-rich gas mixture (19) at the nitrogen outlet, the nitrogen-rich gas mixture comprising a higher nitrogen content than the original gas mixture (31) when it is introduced at the air inlet. - Inertization loop, - Fuel pipe (16), said fuel pipe (16) is used to transport fuel or a mixture including fuel, in: - The nitrogen outlet of the air separation device is hydraulically connected to the inerting circuit. - The oxygen output port of the air separation device is hydraulically connected to the injection device (12). The inerting circuit is characterized by being hydraulically connected to a peripheral channel (17) surrounding the fuel pipe (16), wherein the fuel is hydrogen. The aircraft further includes an engine compartment (34) housing the combustion engine, and The inerting circuit is also hydraulically connected to the upper part of the engine compartment (34) of the aircraft to inertate the engine compartment (34).

2. The aircraft according to claim 1, further characterized in that: The aircraft further includes a cabin, and The intake of the air separation device (18) is hydraulically connected to receive cabin air.

3. The aircraft of claim 1 or 2, further characterized by, The aircraft includes an engine controller (39) adapted to control at least one of the following streams: a raw gas mixture stream, an oxygen-enriched gas mixture stream, a nitrogen-enriched gas mixture stream, and a fuel stream (24) for the combustion engine (38).

4. The aircraft of claim 1 or 2, further characterized by, The hydraulic circuit between the oxygen outlet of the air separation device (18) and the injection device (12) includes a pump (36).

5. The aircraft according to claim 1 or 2, further characterized in that, The injection device (12) is adapted to inject a mixture of oxygen-enriched gas and fuel into the combustion chamber (27) in the region where fuel combustion primarily occurs.

6. The aircraft according to claim 1 or 2, further characterized in that, The aircraft includes a premixer (13), the premixer: -Including an oxygen inlet adapted to receive a stream of oxygen-enriched gas mixture. -Including a fuel inlet adapted to receive a fuel flow (24), - It is adapted to mix the fuel and the oxygen-enriched gas mixture when fuel is introduced at its fuel inlet and an oxygen-enriched gas mixture is introduced at its oxygen inlet. -Including an output port adapted to output a mixture of fuel and oxygen-enriched gas.

7. The aircraft according to claim 1 or 2, further characterized in that, The nitrogen outlet of the air separation device is hydraulically connected to the combustion chamber (27) via a controlled safety valve (23).

8. A method for operating a combustion engine (38) of an aircraft, wherein: - An oxygen-rich gas mixture stream and a nitrogen-rich gas mixture stream are generated from the air stream by an air separation device (18). - The oxygen-enriched gas mixture stream, along with fuel, is injected into the combustion chamber (27) of the engine via the injection device (12). - Inject the nitrogen-rich gas mixture stream into the inerting circuit. The feature is that at least a portion of the nitrogen-rich gas mixture stream is guided around the fuel pipe (16), the fuel being hydrogen, and at least a portion of the nitrogen-rich gas mixture stream is guided to the upper part of the engine compartment (34) of the aircraft to inertate the engine compartment (34), the engine compartment (34) housing the combustion engine (38).

9. The method according to claim 8, further characterized in that, The combustion engine (38) can be shut down by introducing a nitrogen-rich gas mixture stream instead of a fuel stream into the combustion chamber (27) of the combustion engine.

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