Aircraft including an air separation unit and method of operating the same

Abstract

To provide an aircraft comprising an air separation device, and a method of operating the aircraft.SOLUTION: An aircraft includes a combustion engine with a combustion chamber, and an injection device for injecting fuel into the combustion chamber. The invention also relates to a method of operating the aircraft. The aircraft also includes an air separation device adapted to separate air into an oxygen-enriched gas mix and a nitrogen-enriched gas mix, where the oxygen-enriched gas mix is injected into the combustion chamber with the fuel while the nitrogen-enriched gas mix is used to make inert at least some portions of the aircraft in the environment of the combustion engine.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to aircraft inerting systems, and more particularly to aircraft including air separation units adapted to provide nitrogen-enriched air for inerting certain areas of the aircraft. [Background technology]

[0002] An important aspect of aircraft safety involves the inerting of hazardous areas of an aircraft. In particular, in aircraft that include combustion engines, fuel systems and fuel tanks may be inerted to ensure low levels of oxygen and thereby avoid fire or explosion.

[0003] Patent document 1 discloses an aircraft having an air separation module for generating a nitrogen-enriched supply to a fuel tank. This makes it possible to inert the fuel tank by dramatically reducing the oxygen content of the gas mixture surrounding the fuel in the fuel tank. This document provides insight into the temperature control of the air supplied to the air separation module to increase its operational life.

[0004] Such an aircraft does not optimize the use and weight of the inerting system installed on the aircraft. Furthermore, some areas of the aircraft may not be inerted by the system according to this document.

[0005] Furthermore, the fuel efficiency of an aircraft is an important criterion in aircraft design, as an aircraft with low fuel consumption has a low environmental impact and allows its operating costs to be optimized.

[0006] In (Patent Document 2), a system is provided in which a significant amount of oxygen is produced by a ceramic air separator and is cooled and stored on board to start air-breathing engines at high altitudes in case of emergency. However, such a system only covers particularly severe and very rare emergency situations, and consequently has a significant impact on the fuel efficiency of aircraft equipped with such a system.

[0007] Additionally, there is a need for aircraft that have high efficiency and low emissions of pollutants, particularly nitrogen oxides (NOx).

[0008] This means that in the future, all of an aircraft's onboard power can be used during flight, whereas this is not the case on current commercial aircraft. Current aircraft carry much more power generating capacity than they actually use during flight. In particular, current commercial aircraft have auxiliary power units (APUs) that are used as safety generators only while on the ground or in some emergency situations. Optimizing onboard power generation in this way means that all engines can be used during the various stages of flight.

[0009] Additionally, as H2 is being explored as an alternative fuel in the aerospace industry, engine systems must be scrutinized to be safe and efficient in the case of the use of H2 as a fuel.

[0010] The use of H2 (especially in areas of the aircraft that may not previously have been used continuously during flight) creates a need for inerting new areas of the aircraft as well as new systems, methods of operation, and aircraft configurations that can meet flight requirements in terms of safety and fuel efficiency. [Prior art documents] [Patent documents]

[0011] [Patent Document 1] U.S. Patent No. 9,272,790 [Patent Document 2] U.S. Patent No. 5,131,225 [Patent Document 3] French Patent No. 3011484 Summary of the Invention [Problem to be solved by the invention]

[0012] The present invention aims to provide an aircraft inerting system (and more generally an aircraft) as well as a method of operating an aircraft inerting system that provides a solution 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 burn efficiency.

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

[0016] The present invention proposes an aircraft comprising: -Combustion engines, including: ●Combustion chamber, an injection device including a fuel intake adapted to receive a supply of fuel at the fuel intake and inject fuel into a combustion chamber; -Air separation units, including: an air intake adapted to take in an original gas mixture comprising at least oxygen and nitrogen; an oxygen output, wherein the air separation unit is adapted to output an oxygen-enriched gas mixture having an oxygen content higher than the oxygen content of the original gas mixture when an original gas mixture is introduced at the air intake; and a nitrogen output, wherein the air separation unit is adapted to output a nitrogen-enriched gas mixture having a nitrogen content higher than the nitrogen content of the original gas mixture when an original gas mixture is introduced at the air intake. - a nitrogen output of the air separation unit fluidly connected to the inerting circuit; characterised in that the oxygen output of the air separation unit is fluidly connected to the injection device.

[0017] Throughout the text, the term "combustion engine" is used for an internal combustion engine in which a fuel or mixture of fuels is oxidized with oxygen and the chemical energy thereby released is converted into mechanical power.

[0018] The air separation unit is adapted to receive at its inlet a source gas mixture comprising at least nitrogen and oxygen, such as air, and to provide a stream of oxygen-enriched gas mixture and a stream of nitrogen-enriched gas mixture. The air separation unit may, for example, be of the type described in U.S. Pat. No. 5,629,999.

[0019] The original gas mixture may be air with possible variations in composition between low and high altitudes, between atmospheric components and aspirated or recycled cabin air, and the like.

[0020] The injector includes a fuel intake adapted to receive fuel and a fuel output adapted to deliver fuel into the combustion chamber. The injector may be controlled by a computer unit, such as a controller.

[0021] In an aircraft according to the invention, both the nitrogen-enriched gas mixture and the oxygen-enriched gas mixture produced by the air separation unit are used by the aircraft, resulting in an optimization of the weight of the air separation unit, specifically, nitrogen is used to inerte certain areas of the aircraft while oxygen is used to improve combustion in the combustion engines.

[0022] Injection of an oxygen-enriched gas mixture in a combustion engine, and particularly via an injector, allows targeting certain areas of the combustion chamber with a higher proportion of oxygen. In particular, in turbine engines, only about 20-30% of the total oxygen intake by the engine contributes to combustion. Only about 10% is consumed in the first combustion stage, at the beginning of the primary combustion zone, where temperatures are highest and, consequently, NOx formation is also highest. By proposing to inject an oxygen-enriched gas mixture together with the fuel, the oxygen ratio in the first combustion zone in the aircraft engine according to the present invention is much higher, resulting in improved combustion and a reduced amount of nitrogen. Thus, the present invention reduces the formation of NOx due to the presence of nitrogen in the first stage of fuel oxidation (where temperatures are highest in the combustion chamber).

[0023] Furthermore, the engine's air intake directly from the atmosphere can be slightly reduced thanks to the injection of an oxygen-enriched gas mixture into the combustion chamber, which allows for a reduction in engine size, thereby providing a lighter aircraft.

[0024] The present invention therefore proposes a highly efficient aircraft that emits very low levels of NOx.

[0025] The deactivation circuit may be fluidly connected to an engine bay of an aircraft, the engine bay housing a combustion engine.

[0026] The combustion engine may be an auxiliary power unit.

[0027] The engine bay may be a compartment located within the rear fuselage of the aircraft.

[0028] The aircraft according to the invention makes it possible to fully utilize the auxiliary power unit and to optimize its efficiency.

[0029] The deactivation circuit may be fluidly connected at the top of the engine compartment.

[0030] Injection of a nitrogen-enriched gas mixture in the upper part of the engine bay makes it possible to specifically evacuate this part of the engine bay. Thus, the accumulation of light gases such as H2 in the upper part of the engine bay can be avoided. Indeed, if the auxiliary power unit is at least partly supplied with H2, the inerting of the engine bay or at least some areas of the engine bay is very beneficial for the safety of the aircraft.

[0031] Thus, the air separation unit may be a dedicated unit for the auxiliary power unit, the air separation unit may provide a nitrogen-enriched gas mixture for inerting only in the engine compartment, or the air separation unit may provide an oxygen-enriched gas mixture for injection in only the auxiliary power unit combustion chamber.

[0032] The aircraft may include a nitrogen-enriched gas mixing circuit connected to the nitrogen output of the air separation unit. The nitrogen-enriched gas mixture may be used to dilute any fuel vapors in some areas of the aircraft where such vapors may be ignited by other factors (e.g., a heat source).

[0033] The nitrogen-enriched gas mixing circuit may include one or more nitrogen ports for injecting the nitrogen-enriched gas mixture at one or more specific locations. In particular, locations with a risk of overheating or fire may be identified during design and therefore provided with such nitrogen ports for injecting nitrogen during nominal aircraft (engine) operation or immediately upon command. Targeted injection of the nitrogen-enriched gas mixture on hot surfaces allows these surfaces to cool without ignition risk thanks to its very low O2 levels. The O2 level of the nitrogen-enriched gas mixture may be beneficially below 8%, in particular about 4% or less.

[0034] A nitrogen-enriched gas mixture flow may also be used to surround components with high ignition risks with a large amount of inert nitrogen-enriched gas mixture.

[0035] The nitrogen port may be controlled, or a valve on the circuit leading to the valve may be controlled.

[0036] Thus, in the method according to the invention, nitrogen is injected towards a target area of ​​the aircraft, more particularly towards a target area in the engine bay, a specific local area that can be identified as having a higher risk of leakage or a higher risk of fire or explosion in the presence of fuel around it.

[0037] The nitrogen-enriched gas mixture can also be injected to smother a fire or combustion engine when a risk is detected. The nitrogen-enriched gas mixture stream can, for example, be directed entirely towards the area where a fire has occurred or into the entire engine compartment when a fire is detected.

[0038] The aircraft may further include a nitrogen-enriched gas mixture tank fluidly connected to the nitrogen output of the air separation unit to provide a nitrogen-enriched gas mixture reserve for use in the event of an emergency, such that a quantity of the nitrogen-enriched gas mixture can be released to prevent or smother a fire.

[0039] The use of nitrogen-enriched gas mixtures to limit flammability in some areas and / or to smother fires may reduce the need for fire-fighting equipment on board the aircraft, thereby allowing for further reductions in aircraft weight.

[0040] The inerting circuit may be fluidly connected to a peripheral channel around the fuel hose. The peripheral channel may also be referred to as the "outer wall" surrounding the pipe. Inerting of the fuel hose may be achieved in this way. This feature of the invention is particularly important for light fuels such as H2. Indeed, H2 has a very small molecular size. Therefore, fuel hoses containing H2 may be more vulnerable to leaks, sweating, or diffusion.

[0041] A hose with a surrounding channel filled with an inert gas, such as a nitrogen-enriched gas mixture, eliminates any hazards due to this particular property of H2.

[0042] In the method according to the invention, at least a portion of the nitrogen-enriched gas mixture may be directed around the fuel pipe.

[0043] Thus, a flow of the nitrogen-enriched gas mixture can be maintained within the peripheral channel. The nitrogen-enriched gas mixture flow can then be ejected outside the aircraft (into the atmosphere) so that any fuel vapors are vented. Thus, an inerting circuit that includes at least a portion of the peripheral channel can have an output toward the outside of the aircraft. Thus, any fuel that leaks from the fuel hose into the peripheral channel can be safely contained and removed outside the aircraft.

[0044] The air separation unit intake may be fluidly connected to passenger cabin air.

[0045] One or more hydraulic devices, such as pumps, valves, etc., may be located in the cabin air circuit between the passenger cabin air and the intake.

[0046] Air separation systems are sensitive to ozone present in higher atmospheric layers. For this reason, air separation systems dedicated to inerted fuel tanks are typically associated with ozone converters. Because cabin air is already depleted of ozone present therein, the air separation system of the present invention does not need to be associated with an ozone converter. This keeps the complexity and weight of the aircraft of the present invention to a minimum.

[0047] Alternatively, or in combination, in some embodiments, the intake of the air separation unit may be fluidly connected to the atmosphere (particularly at low altitudes).

[0048] One or more hydraulic devices, such as pumps, valves, etc., may be located on the air circuit between the original air source, such as the passenger cabin, and the intake of the air separation unit. The original air may also be conditioned in temperature to optimize the operation and operating life of the air separation unit.

[0049] The aircraft may include an engine controller adapted to control at least one flow selected from the flow of the original gas mixture, the flow of the oxygen-enriched gas mixture, the flow of the nitrogen-enriched gas mixture, and the flow of fuel for the combustion engine.

[0050] The engine controller can be of any type within the processing unit.

[0051] The controller may control one or more of the flows of the original gas mixture, the nitrogen-enriched gas mixture, or the oxygen-enriched gas mixture so as to tune the injection of each gas flow to the engine operation. As described with respect to the use of the nitrogen-enriched gas mixture in the event of an emergency or identified risk, the controller may control the flow of the nitrogen-enriched gas mixture to adapt the use of the nitrogen-enriched gas mixture to this situation.

[0052] In the same way, the controller may adapt the amount of oxygen-enriched gas mixture injected into the combustion engine.

[0053] The hydraulic circuit between the oxygen output of the air separation unit and the injection system includes a pump.

[0054] The pump is adapted to increase the pressure of the oxygen-enriched gas mixture.

[0055] More specifically, the pump is placed in a hydraulic circuit between the oxygen output of the air separation unit and the mixing chamber or premixer so that the oxygen-enriched gas mixture is injected into the premixer under high pressure.

[0056] The fuel can be H2.

[0057] The fuel intake of the injector may be adapted to receive H2.

[0058] H2 oxidation primarily releases water and NOx. By removing nitrogen from the first combustion stage (i.e., by injecting an oxygen-enriched gas mixture from an air separation unit into the combustion chamber with H2), the inventors have realized that NOx production in an H2-fueled engine can be reduced to nearly zero.

[0059] The injector may be adapted to inject a mixture of oxygen-enriched gas mixture and fuel into an area of ​​the combustion chamber where fuel combustion primarily occurs.

[0060] The oxygen-enriched gas mixture is consumed only in the primary combustion chamber of a combustion engine, which is the area of ​​the combustion chamber having the highest temperature where most of the combustion of fuel and oxygen occurs. This area of ​​the combustion chamber is where it is most necessary to avoid the presence of nitrogen so as to reduce the production of NOx. The inventors have realized that it is not necessary to inject only oxygen into the combustion chamber to dramatically reduce the amount of NOx produced, but rather, injecting an oxygen-enriched gas mixture into a targeted area of ​​the combustion chamber while air continues to be supplied to the rest of the engine, can achieve this result.

[0061] This means that the air separation unit does not need to produce a large amount of oxygen-enriched gas mixture to supply the entire engine, and does not need to be of significant volume and mass since it only produces a small portion of the engine's total oxygen intake.

[0062] The aircraft further an oxygen intake adapted to receive a flow of the oxygen-enriched gas mixture; a fuel intake adapted to receive a fuel flow; - when fuel is introduced at the fuel intake and an oxygen-enriched gas mixture is introduced at the oxygen intake, the fuel and the oxygen-enriched gas mixture are mixed; and It may include a pre-mixer including an output adapted to output a mixture of fuel and an oxygen-enriched gas mixture.

[0063] The pre-mixer includes a mixing chamber in which mixing of fuel and oxygen-enriched gas mixture occurs when fuel is introduced at its fuel intake and the oxygen-enriched gas mixture is introduced at its oxygen intake.

[0064] The fuel intake is fluidly connected to a fuel source, such as a fuel tank, through a fuel circuit and a pump.

[0065] The output of the premixer is fluidly connected to an injector.

[0066] The nitrogen output of the air separation unit may be fluidly connected to the combustion chamber through a controlled relief valve. The combustion engine may be shut down by introducing a flow of the nitrogen-enriched gas mixture in place of the fuel flow in the combustion chamber of the engine.

[0067] The controlled safety valve is closed during nominal use, but in case of emergency, a nitrogen-enriched gas mixture can be injected directly into the engine to smother any combustion and stop it quickly.

[0068] Similarly, the oxygen output of the air separation unit is fluidly connected to the combustion chamber through a controlled valve that is open during nominal operation but can be closed in an emergency so that the oxygen-enriched gas mixture supply to the engine can be cut off in an emergency.

[0069] The aircraft may include other valves to control the flow of the nitrogen-enriched gas mixture and / or the oxygen-enriched gas mixture. For example, fuel pipes may also be inerted and vented with the flow of the nitrogen-enriched gas mixture to ensure that no fuel remains in the fuel pipes. This may be particularly beneficial in fuel pipes leading to the combustion chambers of a combustion engine. Specifically, with light fuels such as H2, venting the fuel pipes may be necessary because the H2 could otherwise pass through the pipes during long periods when the aircraft is parked, thereby posing a risk.

[0070] Thus, the nitrogen-enriched gas mixture flow can be injected relatively high up into the main fuel pipe to the engine prior to engine shutdown to ensure that any fuel in the pipe is replaced by the nitrogen-enriched gas mixture and that there is no residual fuel in the pipe when the engine shuts down due to choking. This provides not only a safe shut-down phase for the engine but also safe operation within the engine compartment thereafter.

[0071] The present invention also extends to a method of operating an engine of an aircraft by: an oxygen-enriched gas mixture stream and a nitrogen-enriched gas mixture stream are produced from an air stream by an air separation unit; An oxygen-enriched gas mixture is injected together with the fuel into the combustion chamber via an injector.

[0072] The nitrogen-enriched gas mixture is injected into the inerting circuit.

[0073] The method according to the invention makes it possible to operate aircraft, particularly aircraft auxiliary power units, with high efficiency, low or no NOx emissions, and very high safety.

[0074] The invention also extends to other possible combinations of the features described in the specification above and in the following specification with reference to the accompanying drawings. In particular, the invention extends to a method including features described in relation to the aircraft; the invention extends to an aircraft including features described in relation to the method.

[0075] Certain specific exemplary embodiments and aspects of the present invention are described in the following specification with reference to the accompanying drawings. [Brief explanation of the drawings]

[0076] [Figure 1] 1 is a schematic diagram of an aircraft according to the present invention including an aft fuselage section having an engine bay that hosts a combustion engine and an air separation unit; [Figure 2] 1 is a schematic view of an engine bay of an aircraft according to the present invention; [Figure 3] 1 is a schematic diagram of an aircraft system according to the present invention; DETAILED DESCRIPTION OF THE INVENTION

[0077] In Figure 1, an aircraft 1 is represented. The aircraft comprises an aft fuselage section 2 in which a combustion engine 38 (more specifically an auxiliary power unit) is mounted. The auxiliary power unit is mounted in the engine bay together with an air separation unit.

[0078] In Figure 2, the engine compartment 34 according to Figure 1 is represented. An auxiliary power unit engine 38 is housed in this engine compartment 34. The engine includes various parts: a compressor 28 for taking in atmospheric air 37 and compressing it; a combustion chamber 27 in which fuel oxidation occurs; a turbine 29 driven by gases formed during combustion; and the exhaust of exhaust gases resulting from combustion into the atmosphere.

[0079] The engine bay also houses a safety / efficiency device 11 according to the present invention. The safety / efficiency device 11 includes at least one air separation device. The safety / efficiency device 11 receives a fuel stream 24 from a fuel source, such as a fuel tank, and an original gas mixture stream from an air source, such as cabin air 31. The safety / efficiency device 11 includes one or more air separation devices that separate the air stream into an oxygen-enriched gas mixture stream and a nitrogen-enriched gas mixture stream. The safety / efficiency device 11 also mixes the fuel and the oxygen-enriched gas mixture to obtain a mixture that can be supplied to the injectors 12 of the combustion chamber 27.

[0080] In some other embodiments of the present invention, some portions of the safety / efficiency device 11 may be outside the engine compartment, particularly the air separation unit may be located outside the engine compartment.

[0081] FIG. 3 shows such a safety / efficiency device 11 in more detail and diagrammatically.

[0082] In this embodiment, the safety / efficiency device 11 includes a single air separation device 18. The air separation device 18 receives cabin air at an intake. The cabin air is compressed by a compressor 35 and supplied to the air separation device 18 at a controlled pressure. The air separation device is adapted to separate the cabin air stream received at its intake into an oxygen-enriched gas mixture stream 26 at an oxygen output and a nitrogen-enriched gas mixture stream 19. The air separation device 18 is, for example, of the type that includes hollow fiber membranes that allow oxygen to pass through its walls, while nitrogen cannot pass through it and therefore flows down the hollow fiber holes.

[0083] The oxygen-enriched gas mixture stream 26 is directed to a pump 36 adapted to pressurize the oxygen-enriched gas mixture stream at a controlled pressure to supply the oxygen-enriched gas mixture stream into the pre-mixer 13. The pre-mixer 13 also receives fuel from the fuel flow line 24. The pre-mixer 13 includes a mixing chamber adapted to mix the oxygen-enriched gas mixture with fuel. The output of the pre-mixer 13 is connected to the input of the injector 12 so that the mixture of fuel and oxygen-enriched gas mixture can be directed to the injector 12. The injector 12 is adapted and positioned to inject the mixture of fuel and oxygen-enriched gas mixture directly into the primary combustion chamber 32 of the combustion chamber 27. The primary combustion chamber 32 of the combustion chamber is where combustion between the fuel and oxygen ignites and where the highest temperature is reached. In effect, more air is drawn from the atmosphere and compressed by the turbine engine's compressor 28 and injected into the primary combustion chamber 32 and secondary section 33. The combusted mixture of fuel and oxygen travels from the primary combustion chamber to the secondary section toward the turbine and exits the turbine. Thus, the temperature in the secondary section 33 of the combustion chamber 27 is lower than the temperature in the primary combustion chamber 32. Injection of fuel and oxygen-enriched air by injectors 12 at the beginning of the primary combustion chamber provides a very pure mixture with low levels of nitrogen, thereby dramatically reducing NOx by-products during combustion.

[0084] Before being brought to the pre-mixer 13, the fuel is extracted from a tank and brought to the pre-mixer 13 by a fuel pipe 16. The fuel pipe 16 may include a double wall forming a peripheral channel 17 around the fuel pipe 16. On Figure 3, only a portion of the double-walled fuel pipe 16 is shown. However, such a fuel pipe may be used on any pipe section to carry fuel or a mixture containing fuel.

[0085] 3, the nitrogen-enriched gas mixture stream 19 is separated into multiple nitrogen-enriched gas mixture streams. A first nitrogen-enriched gas mixture stream 20 is directed toward the peripheral channel 17 around the fuel pipe 16. This ensures that any fuel vapors that may result from permeation or leakage through the walls of the pipe 16 are not only vented by the nitrogen-enriched gas mixture stream, but are also inert by the high nitrogen content nitrogen-enriched gas mixture. The nitrogen-enriched gas mixture stream can then be vented to the atmosphere outside the aircraft, for example through venting ports.

[0086] The second nitrogen-enriched gas mixture stream 21 is directed towards a controlled safety valve or fuel flow shut-off valve 23. This fuel flow shut-off valve 23 allows for disconnecting the fuel flow source from the fuel tank towards the pre-mixer 13. Additionally, this fuel flow shut-off valve 23 allows for the nitrogen-enriched gas mixture stream 21 to be injected into the fuel pipe 16 instead of fuel, for example, towards the pre-mixer 13 up to the combustion chamber 27. When the nitrogen-enriched gas mixture reaches the combustion chamber, combustion is smothered to provide a safe shutdown of the turbine engine.

[0087] Furthermore, when the engine is stopped due to choking, the pipe 16 between the fuel flow shutoff valve 23 and the combustion chamber is also purged of fuel and inerted by the nitrogen-enriched gas mixture flow 21 .

[0088] When the fuel flow shutoff valve 23 is closed to the fuel supply and open to the nitrogen-enriched gas mixture, another shutoff valve 14 can close the oxygen-enriched gas mixture flow to the premixer 13 so that the premixer supplies only the nitrogen-enriched gas mixture to the injection system (and thus the combustion chamber).

[0089] The third nitrogen-enriched gas mixture stream 22 is directed to specific predetermined areas in the engine compartment, such as hot spots that require cooling to reduce ignition risk (areas where leaks of fuel or other flammable products, such as grease, may occur and must be inerted; not shown in FIG. 3). The third nitrogen-enriched gas mixture stream 22 can also be directed toward the top of the engine compartment for exhaust. This is particularly beneficial in the case of lighter than air fuels or H2 combustibles. Thus, the upper part of the engine compartment 34 can be inerted by the nitrogen-enriched gas mixture stream 22 and then exhausted.

[0090] The example aircraft presented in Figures 1-3 also includes an auxiliary power unit fuel system 15. Fuel system 15 is not detailed in Figure 3. 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 environment. Auxiliary power unit fuel system 15 includes a fuel flow filter, a fuel pump, a pressure regulator, a fuel shutoff valve, a fuel control unit, and several sensors (e.g., temperature sensor, pressure sensor). The auxiliary power unit fuel system is adapted to operate properly at low temperatures with fuel containing ice, fuel containing additives, and contaminants.

[0091] The example aircraft shown in Figures 1-3 also includes a controller 39. The controller 39 is adapted to control the flow of the oxygen-enriched gas mixture 26 by controlling the oxygen-enriched gas mixture pump 36. The controller 39 is also adapted to control the flow of fuel 24 to the combustion engine 38 by controlling the fuel system 15. The controller 39 may also control the pre-mixer 13 to control the mixing ratio of the fuel and the oxygen-enriched gas mixture.

[0092] In some other embodiments of the present invention, the controller 39 may also be adapted to control the compressor 35 to control the air supply to the air separation unit 18. The controller may also be adapted to control the fuel shut-off valve 23 and / or the oxygen-enriched gas mixture shut-off valve 14.

[0093] The present invention is not limited to the specific embodiments herein disclosed by way of example, and also encompasses other embodiments not expressly described herein that may include various combinations of the features described herein. [Explanation of symbols]

[0094] 1 aircraft 2 Rear fuselage 11 Safety / Efficiency Devices 12 Injection device 13 Pre-mixer 14 Oxygen-enriched gas mixture shutoff valve 15 Fuel system 16 Fuel pipe 17 ambient channels 18 Air Separation Unit 19 Nitrogen-enriched gas mixture flow 20 first nitrogen-enriched gas mixture stream 21 second nitrogen-enriched gas mixture stream 22 third nitrogen-enriched gas mixture stream 23 Fuel shutoff valve 24 Fuel flow 26 Oxygen-enriched gas mixture flow 27 Combustion chamber 28 Compressor 29 Turbine 31 Original Gas Mixtures 32 Primary combustion chamber 33 Secondary area 34 Engine Room 35 Compressor 36 Oxygen-enriched gas mixture pump 37 Atmosphere 38 Combustion Engine 39 Engine Controller

Claims

1. An aircraft equipped with a combustion engine (38) and an air separation unit (18), The combustion engine (38) a combustion chamber (27); an injector (12) including a fuel intake, the injector (12) being adapted to inject fuel into the combustion chamber upon receiving a supply of fuel at the fuel intake; The air separation unit (18) an air intake adapted to take in an original gas mixture (31) comprising at least oxygen and nitrogen; an oxygen output adapted to receive an original gas mixture (31) at the air intake and for the air separation unit (18) to output an oxygen-enriched gas mixture (26) having an oxygen content higher than the oxygen content of the original gas mixture (31); a nitrogen output adapted to receive an original gas mixture (31) at the air intake and for the air separation unit (18) to output a nitrogen-enriched gas mixture (19) having a nitrogen content higher than that of the original gas mixture (31); the nitrogen output of the air separation unit is fluidly connected to an inerting circuit; the deactivation circuit is fluidly connected to an engine bay (34) of the aircraft; the oxygen output of the air separation unit is fluidly connected to the injector (12); The aircraft is characterized in that the inerting circuit is fluidly connected to a peripheral channel (17) around the fuel hose (16).

2. An aircraft equipped with a combustion engine (38) and an air separation unit (18), The combustion engine (38) a combustion chamber (27); an injector (12) including a fuel intake, the injector (12) being adapted to inject fuel into the combustion chamber upon receiving a supply of fuel at the fuel intake; The air separation unit (18) an air intake adapted to take in an original gas mixture (31) comprising at least oxygen and nitrogen; an oxygen output adapted to receive an original gas mixture (31) at the air intake and for the air separation unit (18) to output an oxygen-enriched gas mixture (26) having an oxygen content higher than the oxygen content of the original gas mixture (31); a nitrogen output adapted to receive an original gas mixture (31) at the air intake and for the air separation unit (18) to output a nitrogen-enriched gas mixture (19) having a nitrogen content higher than that of the original gas mixture (31); the nitrogen output of the air separation unit is fluidly connected to an inerting circuit; the deactivation circuit is fluidly connected to an engine bay (34) of the aircraft; the oxygen output of the air separation unit is fluidly connected to the injector (12); the air separation unit (18) including a pump (36) between the oxygen output of the air separation unit (18) and the injectors (12), the pump delivering the oxygen-enriched gas mixture (26) from the oxygen output towards the injectors (12).

3. 3. An aircraft according to claim 1 or 2, further characterized in that the inerting circuit is fluidly connected at an upper portion of the engine bay (34).

4. 3. The aircraft of claim 2, further characterized in that the inerting circuit is fluidly connected to a peripheral channel (17) around a fuel hose (16).

5. An aircraft according to any one of claims 1 to 4, further characterized in that the intake of the air separation unit (18) is fluidly connected to passenger cabin air (31).

6. 6. The aircraft according to any one of claims 1 to 5, further comprising an engine controller (39) adapted to control at least one flow selected from the flow of original gas mixture (31), the flow of oxygen-enriched gas mixture (26), the flow of nitrogen-enriched gas mixture (19) and the flow of fuel (24) of the combustion engine (38).

7. The fuel intake of the injector (12) is H ２ An aircraft according to any one of claims 1 to 6, further characterized in that it is adapted to receive

8. An aircraft according to any one of claims 1 to 7, further characterized in that the injectors (12) are adapted to inject a mixture of oxygen-enriched gas mixture and fuel into an area of ​​the combustion chamber (27) in which fuel combustion mainly takes place.

9. - includes an oxygen intake adapted to receive a flow of oxygen-enriched gas mixture (26), - includes a fuel intake adapted to receive a fuel flow (24), - upon introduction of fuel at the fuel intake and an oxygen-enriched gas mixture at the oxygen intake, the fuel and the oxygen-enriched gas mixture are mixed; An aircraft according to any one of claims 1 to 8, further characterized in that it comprises a pre-mixer (13) including an output adapted to output a mixture of fuel and an oxygen-enriched gas mixture.

10. An aircraft according to any one of claims 1 to 9, further characterized in that the nitrogen output of the air separation unit is fluidly connected to the combustion chamber (27) through a controlled relief valve (23).

11. A method of operating an engine (38) of an aircraft as claimed in any one of claims 1 to 10, comprising: - an oxygen-enriched gas mixture stream (26) and a nitrogen-enriched gas mixture stream (19) are produced from the air stream (31) by an air separation unit (18); - said oxygen-enriched gas mixture is injected together with the fuel in the combustion chamber (27) via an injector (12); - A method for operating an aircraft engine (38) by injecting said nitrogen-enriched gas mixture into an inerting circuit.

12. The fuel is H ２ The method of claim 11 further characterized by:

13. 13. The method of claim 11 or 12, further characterized in that at least a portion of the nitrogen-enriched gas mixture is directed around a fuel pipe (16).

14. 14. The method according to any one of claims 11 to 13, further characterized in that the combustion engine (38) can be shut off by introducing a flow of a nitrogen-enriched gas mixture instead of a flow of fuel in a combustion chamber (27) of the engine.

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