Patent Description:
Some aircraft include an Environmental Control System (ECS) that supplies oxygen, thermal control, and cabin pressurization for the crew and passengers. In an ECS, air is compressed to high pressure and temperature, such as with bleed air from the compressor stage of an engine. The compressed air is fed to an Environmental Control Unit (ECU) via a flow control valve, where the air is conditioned by heat exchangers and an Air-Cycle Machine (ACM), if needed, that cools the air to a desired temperature. The conditioned air is then delivered to the cabin and cockpit at the desired temperature and pressure.

A pressurized aircraft also includes an emergency oxygen system that activates in the event that the cabin becomes depressurized. For a typical emergency oxygen system, oxygen masks will automatically deploy above or in front of the passenger seats and crew seats. Oxygen is supplied to the masks with a chemical oxygen generator or a gaseous manifold system. The chemical oxygen generator uses an exothermic reaction (e.g., igniting a mixture of sodium chlorate and iron powder) to create a supply of oxygen. The gaseous manifold system uses one or more tanks of oxygen, usually stored in the cargo hold, to supply the oxygen.

It may be desirable to identify other ways of supplying or supplementing oxygen to an ECS, the emergency oxygen system, or other subsystems of an aircraft.

<CIT> in an abstract states "A gas generation method and apparatus, capable of use in an aircraft, generates oxygen with at least one On Board Oxygen Generating System (OBOGS) (<NUM>,<NUM>,<NUM>) and generates an inert gas with at least one On Board Inert Gas Generating System (OBIGGS) (<NUM>,<NUM>) and selectively supplies an auxiliary supply of inert gas utilizing a waste gas output of the at least one OBOGS. The inert gas can include nitrogen. An auxiliary source of oxygen can also be provided. Control valves (<NUM>,<NUM>) can be used to selectively supply the waste gas output of the at least one OBOGS to the atmosphere or to cither of two locations. The oxygen can be used in a passenger compartment (<NUM>) of the aircraft and the inert gas use in either a fuel tank (<NUM>) or cargo bay (<NUM>) of the aircraft.

<CIT> in an abstract states "An aircraft air supply system may include a primary duct (<NUM>) to supply a primary air flow to a flight deck (<NUM>) of an aircraft. A nitrogen generating system (<NUM>) may be configured for generating nitrogen enriched air and oxygen enriched air. A secondary duct (<NUM>) may be provided for channeling the oxygen enriched air from the nitrogen generating system (<NUM>) to the primary duct (<NUM>). The flow of the oxygen enriched air into the primary duct (<NUM>) and to the flight deck (<NUM>) may be controlled to reduce an effective altitude of the flight deck (<NUM>).

<CIT> in an abstract states "An on board inert gas generation system for an aircraft receives air from a relatively low pressure source such as low pressure engine bleed air or ram air and passes it to a positive displacement compressor (<NUM>) to increase the pressure thereof to be suitable for supply to an air separation module (<NUM>). The speed of the positive displacement compressor may be adjusted across a wide range in order to provide efficient operation in cruise and descent phases of aircraft flight. The operating speed of the compressor and/or the flow rate from the ASM to the space to be inerted may be controlled in accordance with at least one of the gas composition in the space to be inerted, the flight condition, and the ullage volume.

<CIT> in an abstract states "The invention pertains to an inerting system for an aircraft featuring at least one air separation module with at least one air inlet, a first air outlet and a second air outlet. The air separation module is designed for splitting an input air flow into a first air flow and a second air flow, wherein the first air flow is enriched with oxygen in comparison with the input air flow and discharged at the first air outlet and the second air flow is enriched with nitrogen in comparison with the input air flow and discharged at the second air outlet. In comparison with known inerting systems, the inerting system according to the invention is characterized in that the air inlet can be connected to an air extraction point in an air processing system and the inerting system is designed for routing the first air flow into a cabin to be air-conditioned.

Examples described herein reuse oxygen enriched air from an inerting system and/or a stand-alone air separator for one or more subsystems of an aircraft. An inerting system or air separator operates by separating a pressurized air stream into oxygen enriched air and an inert gas (e.g., nitrogen). In a traditional aircraft that uses an inerting system, the inert gas is fed to a fuel tank to safeguard against fire or explosion, while the oxygen enriched air is dumped through a ram duct. In the examples described herein, the oxygen enriched air is fed to an ECS, an emergency oxygen system, and/or another subsystem of the aircraft. Thus, the oxygen enriched air is not wasted, but is reused by another system of the aircraft.

The aircraft includes an oxygen supply subsystem configured to supply oxygen to a cabin of the aircraft, and an air separator configured to receive a pressurized air stream, to separate the pressurized air stream into oxygen enriched air and an inert gas, and to feed the oxygen enriched air to the oxygen supply subsystem.

In another example, the air separator is part of an inerting system configured to feed the inert gas to a fuel tank of the aircraft.

The oxygen supply subsystem comprises an emergency oxygen system, and the air separator is configured to feed the oxygen enriched air to the emergency oxygen system.

The aircraft further includes a pressure sensor configured to detect a cabin decompression event on the aircraft, and a manifold configured to feed the oxygen enriched air from the air separator to the emergency oxygen system in response to the cabin decompression event.

In another example, the emergency oxygen system includes masks configured to automatically deploy in response to the cabin decompression event.

In another example, the emergency oxygen system includes outlet vents configured to supply oxygen to particular regions within the cabin in close proximity to seats in response to the cabin decompression event.

The oxygen supply subsystem comprises an air distribution subsystem, and the air separator is configured to feed the oxygen enriched air to the air distribution subsystem.

The aircraft further includes a pressure sensor configured to detect a cabin decompression event on the aircraft, and a manifold configured to feed the oxygen enriched air from the air separator to the air distribution subsystem in response to the cabin decompression event.

The aircraft further includes an oxygen sensor configured to measure oxygen content at the oxygen supply subsystem, and preferably a regulator configured to regulate the oxygen enriched air fed to the oxygen supply subsystem based on the oxygen content.

In another example, the pressurized air stream comprises bleed air from an engine of the aircraft.

In another example, the pressurized air stream comprises compressed air from a compressor on the aircraft.

A method of supplying oxygen enriched air to an aircraft is provided. The method comprises receiving a pressurized air stream at an air separator on an aircraft, separating the pressurized air stream into oxygen enriched air and nitrogen enriched air at the air separator, feeding the nitrogen enriched air to a fuel tank of the aircraft, detecting a cabin decompression event on the aircraft, and feeding the oxygen enriched air to an emergency oxygen system in response to the cabin decompression event.

In another example, the method further comprises feeding the oxygen enriched air to an air distribution subsystem of the aircraft when a cabin decompression event is not detected.

In another example, the method further comprises measuring oxygen content in the emergency oxygen system and/or the air distribution subsystem, and regulating the oxygen enriched air fed to the emergency oxygen system and/or the air distribution subsystem based on the oxygen content.

The method further comprises feeding the oxygen enriched air to an air distribution subsystem of the aircraft in response to the cabin decompression event.

The features, functions, and advantages that have been discussed can be achieved independently in various examples or may be combined in yet other examples, further details of which can be seen with reference to the following description and drawings.

Some examples are now described, by way of example only, with reference to the accompanying drawings.

The figures and the following description illustrate specific exemplary examples. It will be appreciated that those skilled in the art will be able to devise various arrangements that, although not explicitly described or shown herein, embody the principles described herein and are included within the contemplated scope of the claims that follow this description. Furthermore, any examples described herein are intended to aid in understanding the principles of the disclosure, and are to be construed as being without limitation. As a result, this disclosure is not limited to the specific examples or examples described below, but by the claims.

<FIG> depicts a side view of an aircraft <NUM> in an illustrative example. Aircraft <NUM> includes a nose <NUM>, wings <NUM>, a fuselage <NUM>, a tail <NUM>, and engines <NUM>. Within fuselage <NUM> is a cockpit <NUM> and a cabin <NUM>. Cockpit <NUM> (or flight deck) is the section or area from which pilots control aircraft <NUM>, and includes the flight controls and flight instruments. Cabin <NUM> is the section or area where passengers travel, and includes rows of seats. Although aircraft <NUM> has been depicted to have a particular configuration for purposes of discussion, aircraft <NUM> may have other configurations in other examples.

<FIG> is a schematic diagram of aircraft <NUM> in an illustrative example. It is assumed in this example that aircraft <NUM> is pressurized. Thus, aircraft <NUM> includes one or more oxygen supply subsystems <NUM> that are configured to supply, convey, or deliver oxygen to crew members and/or passengers within cockpit <NUM> and/or cabin <NUM>. An oxygen supply subsystem <NUM> may have a variety of structures to delivery oxygen, which may include one or more of the following: one or more inlets <NUM> configured to receive a supply of oxygen, one or more fans <NUM> to create or control an airflow that includes the oxygen, one or more ducts <NUM> configured to convey an airflow to locations of cockpit <NUM> and/or cabin <NUM>, one or more manifolds <NUM> configured to direct airflows to ducts <NUM> and/or control flow rate, one or more outlets <NUM> (e.g., outlet vents, masks, etc.) configured to release an airflow into cockpit <NUM> and/or cabin <NUM>, and/or other components such as piping, hoses, etc. The structure of an oxygen supply subsystem <NUM> may vary depending on the type of subsystem. One example of an oxygen supply subsystem <NUM> is an ECS <NUM>. ECS <NUM> is a system responsible for supplying air, pressurizing and ventilating cabin <NUM>, controlling temperature, and other tasks. In this example, ECS <NUM> includes an Environmental Control Unit (ECU) <NUM>, an air distribution subsystem <NUM>, an exhaust subsystem <NUM>, a recirculation subsystem <NUM>, a temperature control subsystem <NUM>, and a pressure control subsystem <NUM>. The configuration of ECS <NUM> is an example, and ECS <NUM> may include more or less subsystems in other examples.

ECU <NUM> is configured to condition air that is supplied to cockpit <NUM> and/or cabin <NUM>. <FIG> is a schematic diagram of ECU <NUM> in an illustrative example. ECU <NUM> includes a flow control valve <NUM>, one or more heat exchangers <NUM>, an Air-Cycle Machine (ACM) <NUM>, a bypass <NUM>, and a water separator <NUM>. Flow control valve <NUM> receives compressed air, and regulates the amount of compressed air that enters cabin <NUM>. Flow control valve <NUM> may receive the compressed air (i.e., bleed air) from one or more compressor stages of an engine <NUM> when aircraft <NUM> is in flight. Flow control valve <NUM> may receive the compressed air from an auxiliary power unit (APU), a ground cart (GCU), airport high-pressure hydrants, etc., when aircraft <NUM> is on the ground. The compressed air passing through flow control valve <NUM> travels through heat exchanger(s) <NUM>, where it is cooled by outside air to a desired temperature. At cruising altitude where the outside air is cold, the compressed air may be cooled sufficiently by heat exchanger(s) <NUM> and does not need further cooling by ACM <NUM>. Thus, the compressed air travels through bypass <NUM> instead of through ACM <NUM>. At lower altitudes or on the ground, the compressed air may be further cooled by traveling through ACM <NUM>, which includes one or more air conditioning packs. The compressed air then travels through water separator <NUM>, which controls the moisture level of the air. The air leaving ECU <NUM> is "conditioned air", that is fed to air distribution subsystem <NUM> (see <FIG>). The configuration of ECU <NUM> is an example, and ECU <NUM> may include more or less elements in other examples.

In <FIG>, air distribution subsystem <NUM> is configured to distribute the conditioned air from ECU <NUM> to cockpit <NUM> and cabin <NUM>. Air distribution subsystem <NUM> may distribute the conditioned air to different zones of aircraft <NUM>, and each zone may have its own ducting system to provide independent temperature control for each zone. For example, a narrow-body aircraft may have two zones; one for cockpit <NUM> and one for cabin <NUM>. A wide-body aircraft may have multiple zones for cabin <NUM> that are each independently temperature controlled (e.g., one for first class, one for business class, and one for economy). Exhaust subsystem <NUM> (which may be considered part of air distribution subsystem <NUM>) removes air from cockpit <NUM> and cabin <NUM>. Air is generally exhausted from cabin <NUM> through floor-level grilles or exhaust vents that run the length of cabin <NUM> on both sides along a sidewall. <FIG> illustrates an air distribution subsystem <NUM> in an illustrative example. Distribution of air is managed with a system of air ducts throughout cabin <NUM>. Typically, air is ducted to and released from overhead vents, where it circulates and flows out floor-level exhaust vents. Ducting is hidden below the cabin floor and behind walls and ceiling panels depending on the aircraft. In this example, air distribution subsystem <NUM> may include a mixing manifold <NUM>, one or more riser ducts <NUM>, one or more overhead supply ducts <NUM>, one or more overhead ducts <NUM>, and one or more outlet vents or overhead vents, which is not visible in <FIG>. Although not shown, air distribution subsystem <NUM> may further include recirculation filters, one or more fans, plenum assemblies, etc..

<FIG> is a cross-sectional view of aircraft <NUM> in an illustrative example. The view in <FIG> is across cut plane <NUM>-<NUM> in <FIG>. Fuselage <NUM> includes an upper section <NUM>, which includes a floor <NUM>, a ceiling <NUM>, and sidewalls <NUM> that form cabin <NUM>, which includes seats <NUM> for the passengers. Fuselage <NUM> also includes a lower section <NUM>, which includes a cargo area <NUM>. <FIG> further illustrates an outboard direction that proceeds towards an external surface of aircraft <NUM>, and an inboard direction that proceeds towards the interior (e.g., cabin <NUM>) of aircraft <NUM>.

Air distribution subsystem <NUM> includes overhead duct <NUM> that delivers conditioned air through cabin <NUM> or through one or more zones of cabin <NUM>. There may be more or less overhead ducts <NUM> for air distribution subsystem <NUM> than is shown in <FIG>, and the overhead ducts <NUM> may be positioned in different locations in other examples. Airflow is released from overhead duct <NUM> into cabin <NUM> through one or more outlet vents <NUM>. Although outlet vents <NUM> are shown as overhead vents in this example, outlet vents <NUM> may be disposed at different locations as desired. The arrows in <FIG> illustrate how the conditioned air circulates through cabin <NUM>. Air is released from outlet vents <NUM> and circulates through cabin <NUM>. The air is evacuated from cabin <NUM> through grills or exhaust vents <NUM>. The exhaust air may be directed alongside or through the cargo area <NUM>, where it may provide some heating or cooling. The exhaust air is then exhausted outboard through outflow valves (not shown) controlled to maintain the desired cabin pressure.

In <FIG>, recirculation subsystem <NUM> is an optional system that recycles some exhaust air back into cabin <NUM> or back to ECU <NUM>. Temperature control subsystem <NUM> is configured to control ECU <NUM> to discharge conditioned air at a desired temperature. Pressure control subsystem <NUM> controls the rate of change of cabin pressure during climb and descent of aircraft <NUM>, and establishes the cabin pressure at cruising altitude to create a safe environment in cabin <NUM>. The pressure inside cabin <NUM> is equivalent to an altitude, so the cabin pressure is referred to as a "cabin altitude". For example, if the pressure of the cabin is about <NUM> N/mm2 (<NUM> lbs/in2), then the cabin altitude is about <NUM> (<NUM> feet). This pressure is equivalent to what a human would experience if he/she were at an elevation of <NUM> (<NUM> feet). The maximum cabin altitude allowed by transport category aircraft regulations is <NUM> (<NUM> feet), so pressure control subsystem <NUM> attempts to maintain the pressure inside cabin <NUM> below that altitude during normal operation.

Another example of an oxygen supply subsystem <NUM> is an emergency oxygen system <NUM>. Emergency oxygen system <NUM> is configured to supply oxygen to crew members and passengers in response to a loss of pressurization of cabin <NUM>, which is referred to as a cabin depressurization event. Emergency oxygen system <NUM> includes a pressure sensor <NUM>, which comprises a sensor configured to measure the pressure inside of cabin <NUM> and/or cockpit <NUM> of aircraft <NUM>. Pressure sensor <NUM> is configured to detect a cabin decompression event on aircraft <NUM>. For example, if the cabin altitude reaches or exceeds a threshold (e.g., <NUM>, which corresponds to <NUM> feet), then pressure sensor <NUM> may detect a cabin decompression event. Emergency oxygen system <NUM> may further include supply ducts <NUM>, masks <NUM>, and/or outlet vents <NUM>. Masks <NUM> are configured to automatically deploy in response to a cabin decompression event, and includes a facial cup and elastic bands for securing mask <NUM> to the face of a passenger or crew member. Outlet vents <NUM> may be used in place of or in addition to masks <NUM> to supply oxygen to particular regions within cabin <NUM>, such as in close proximity to seats <NUM> of aircraft <NUM>. In one example, outlet vents <NUM> of emergency oxygen system <NUM> may include the outlet vents <NUM> of air distribution subsystem <NUM>. In other examples, additional outlet vents <NUM> may be installed in close proximity to seats <NUM> (i.e., overhead or directly in front of seats <NUM>) to provide an airflow directly toward passengers. Emergency oxygen system <NUM> is configured to automatically supply oxygen to cabin <NUM> through masks <NUM> and/or outlet vents <NUM> when the cabin altitude exceeds a threshold. Although not shown, emergency oxygen system <NUM> may further include one or more fans, one or more manifolds, hoses, piping, etc..

In the examples described herein, oxygen enriched air is provided to one or more of the oxygen supply subsystems <NUM> via an air separator. As shown in <FIG>, aircraft <NUM> may further include an inerting system <NUM>. Inerting system <NUM> is part of a Flammability Reduction System (FRS) for aircraft <NUM>. FRS may be considered part of ECS <NUM>, but is shown outside of ECS <NUM> in this example. Inerting system <NUM> is configured to decrease the probability of combustion of flammable materials stored in a fuel tank <NUM> of aircraft <NUM> by replacing the air in fuel tank <NUM> with an inert gas, such as nitrogen, nitrogen enriched air, steam, carbon dioxide, etc. Inerting system <NUM> feeds an inert gas into the ullage of fuel tank <NUM>, which reduces the oxygen concentration of the ullage to below the combustion threshold. Thus, flammable vapors in fuel tank <NUM> are rendered inert, and will not ignite in the presence of an ignition source. Inerting system <NUM> includes an air separator <NUM> (also referred to as an air separation module), which is configured to separate a pressurized air stream into an inert gas (e.g., nitrogen enriched air (NEA)) and oxygen enriched air (OEA). In one example, air separator <NUM> may use fiber membranes to remove oxygen from a pressurized air stream, and generate nitrogen enriched air that is distributed to fuel tank <NUM>. Inerting system <NUM> also includes other components, one of example of which is shown in <FIG>.

<FIG> is a schematic diagram of inerting system <NUM> in an illustrative example. Inerting system <NUM> receives pressurized air stream <NUM> through a shut-off valve <NUM>. Pressurized air stream <NUM> travels through ozone (O3) converter <NUM>, which is a catalytic converter that converts triatomic oxygen (ozone) to biatomic or "regular" oxygen to protect other elements in inerting system <NUM> from oxidation. Pressurized air stream <NUM> then travels through one or more filters <NUM> to a heat exchanger <NUM>, which cools the pressurized air stream <NUM>. For instance, bleed air is really hot when it comes off engine <NUM>, and heat exchanger <NUM> cools the bleed air to protect other elements of inerting system <NUM> and increase their effectiveness. Pressurized air stream <NUM> then travels to air separator <NUM>, which physically separates an inert gas (e.g., nitrogen (N2)) in the air. This separation may be accomplished by running the pressurized air stream <NUM> through semipermeable fibrous tubes. Because almost all of the non-N2 molecules present are smaller than the N2 molecules, those smaller molecules pass through the membranes as oxygen enriched air (OEA); leaving the nitrogen enriched air (NEA) that is fed to fuel tank <NUM> through a flow-control valve <NUM>. A system controller <NUM> receives sensor inputs to control operation of flow-control valve <NUM>, shut-off valve <NUM>, heat exchanger <NUM>, and/or other elements.

In the example shown in <FIG>, air separator <NUM> receives the pressurized air stream <NUM> from an engine <NUM> of aircraft <NUM> as bleed air. In a Boeing <NUM> or <NUM>, for example, bleed air from an engine may be fed to air separator <NUM> of inerting system <NUM>. A regulator <NUM> (e.g., including a flow control valve) may be installed upstream from inerting system <NUM> to control or regulate the bleed air that is fed to air separator <NUM>. Air separator <NUM> separates the pressurized air stream <NUM> into an inert gas <NUM> and oxygen enriched air <NUM>. Air separator <NUM> feeds the inert gas <NUM> to fuel tank <NUM>, and feeds the oxygen enriched air <NUM> to an oxygen supply subsystem <NUM> through a regulator <NUM>.

Regulator <NUM> is configured to control or regulate the oxygen enriched air <NUM> that is fed to an oxygen supply subsystem <NUM>. An oxygen sensor <NUM> is configured to measure oxygen content or an oxygen level in an oxygen supply subsystem <NUM>. For example, oxygen sensor <NUM> may measure the oxygen content in air distribution subsystem <NUM>, emergency oxygen system <NUM>, etc. Oxygen sensor <NUM> is configured to provide a signal to regulator <NUM> and/or a controller <NUM> indicating the oxygen content. Controller <NUM> is configured to determine how much oxygen enriched air <NUM> to supply to oxygen supply subsystem <NUM> based on the oxygen content measured by oxygen sensor <NUM>, and control regulator <NUM> accordingly. Thus, aircraft <NUM> includes a closed-loop system for supplying oxygen enriched air <NUM> to an oxygen supply subsystem <NUM>.

Regulator <NUM> may feed the oxygen enriched air <NUM> directly to an oxygen supply subsystem <NUM>, such as to air distribution subsystem <NUM>, emergency oxygen system <NUM>, and/or another subsystem. In this example, regulator <NUM> may feed the oxygen enriched air <NUM> to a manifold <NUM>, which is configured to control where the oxygen enriched air <NUM> is fed. Manifold <NUM> is coupled to controller <NUM>, which is configured to control manifold <NUM> in response to input from pressure sensor <NUM> and/or other devices or instruments. For example, manifold <NUM> may direct the oxygen enriched air <NUM> to air distribution subsystem <NUM> under normal operating conditions (e.g., cabin altitude is below a threshold), may direct the oxygen enriched air <NUM> to air distribution subsystem <NUM> in response to a cabin decompression event (e.g., the cabin altitude is above a threshold), may direct the oxygen enriched air <NUM> to emergency oxygen system <NUM> in response to a cabin decompression event, or may direct the oxygen enriched air <NUM> to both or other subsystems. Controller <NUM> may also control regulators <NUM>-<NUM> or other devices, and may receive input from pressure sensor <NUM>, oxygen sensor <NUM>, and/or other devices or instruments.

In the example described above, the oxygen enriched air <NUM> from inerting system <NUM> is advantageously reused for air distribution subsystem <NUM>, emergency oxygen system <NUM>, and/or another subsystem. In a traditional aircraft, the oxygen enriched air <NUM> from an inerting system was dumped out a ram duct and wasted. The example described above uses the oxygen enriched air <NUM> from inerting system <NUM> in an effective manner for other subsystems of aircraft <NUM>. For example, the oxygen enriched air <NUM> may be fed to emergency oxygen system <NUM> (or possibly to air distribution subsystem <NUM>) as an oxygen supply during a cabin decompression event, which replaces traditional emergency systems (i.e., a chemical oxygen generator or gaseous manifolds). One technical benefit is that emergency oxygen system <NUM> has an unlimited oxygen supply as long as aircraft <NUM> is airborne, where traditional emergency systems had limited supplies (e.g., fifteen to twenty minutes). Another benefit is that traditional emergency systems do not need to be installed on aircraft <NUM>, which may reduce the weight of aircraft <NUM>. Another benefit is that a chemical oxygen generator uses an exothermic reaction, which may be a fire risk and may produce unhealthy vapors. Yet another benefit is that the oxygen supply is controllable unlike traditional emergency oxygen systems. Additionally or alternatively, the oxygen enriched air <NUM> may be fed to air distribution subsystem <NUM> to enhance the oxygen content of the air in cockpit <NUM> and/or cabin <NUM>. One technical benefit is that the air quality on aircraft <NUM> may be enhanced.

<FIG> is a schematic diagram of aircraft <NUM> in another illustrative example. In this example, air separator <NUM> of inerting system <NUM> receives pressurized air stream <NUM> from a compressor <NUM> instead of a compressor stage of engine <NUM>. Compressor <NUM> is an auxiliary device that generates pressurized air, and may be electrical, hydraulic, pneumatic, etc. For example, a Boeing <NUM> may include an electric-driven compressor that supplies a pressurized air stream to inerting system <NUM> instead of using bleed air from an engine. Controller <NUM> may control compressor <NUM> to regulate the air that is fed to air separator <NUM>.

<FIG> is a schematic diagram of aircraft <NUM> in another illustrative example. In this example, aircraft <NUM> includes a stand-alone air separator <NUM>, which is separate or independent from an inerting system. Air separator <NUM> receives the pressurized air stream <NUM> from an engine <NUM> of aircraft <NUM> as bleed air. Air separator <NUM> separates the pressurized air stream <NUM> into an inert gas <NUM> and oxygen enriched air <NUM>. Air separator <NUM> feeds the oxygen enriched air <NUM> to an oxygen supply subsystem <NUM> through regulator <NUM>, and dumps the inert gas <NUM>.

<FIG> is a schematic diagram of aircraft <NUM> in another illustrative example. In this example, aircraft <NUM> again includes a stand-alone air separator <NUM>. Air separator <NUM> receives the pressurized air stream <NUM> from a compressor <NUM> instead of a compressor stage of engine <NUM>.

<FIG> is a flow chart illustrating a method <NUM> of supplying oxygen enriched air to an aircraft in an illustrative example not falling under the scope of the appended claims. The steps of method <NUM> will be described with respect to aircraft <NUM> of <FIG> or <FIG>, although one skilled in the art will understand that the methods described herein may be performed on other types of aircraft. The steps of the methods described herein are not all inclusive and may include other steps not shown The steps for the flow charts shown herein may also be performed in an alternative order.

Air separator <NUM> on aircraft <NUM> receives a pressurized air stream <NUM> (step <NUM>). For example, air separator <NUM> may receive the pressurized air stream <NUM> as bleed air from an engine <NUM> of aircraft <NUM> (see <FIG>). In another example, air separator <NUM> may receive the pressurized air stream <NUM> from a compressor <NUM> on aircraft <NUM> (see <FIG>). Air separator <NUM> separates the pressurized air stream <NUM> into oxygen enriched air <NUM> and an inert gas <NUM>, such as nitrogen enriched air (step <NUM>). Air separator <NUM> feeds the inert gas <NUM> to a fuel tank <NUM> of aircraft <NUM> (step <NUM>). This assists in flammability reduction by replacing the air in fuel tank <NUM> with the inert gas.

The oxygen enriched air <NUM> may be reused in an oxygen supply subsystem <NUM> of aircraft <NUM>. For instance, pressure sensor <NUM> (and/or an associated controller) monitors for a cabin decompression event (step <NUM>). When pressure sensor <NUM> detects a cabin decompression event on aircraft <NUM> (e.g., cabin altitude exceeds a threshold), manifold <NUM> feeds the oxygen enriched air <NUM> from air separator <NUM> to emergency oxygen system <NUM> (step <NUM>). When there is no cabin decompression event, manifold <NUM> may feed the oxygen enriched air <NUM> to air distribution subsystem <NUM> (step <NUM>). In either case, oxygen sensor <NUM> may measure the oxygen content in emergency oxygen system <NUM> and/or air distribution subsystem <NUM> (step <NUM>), and regulator <NUM> may regulate the oxygen enriched air <NUM> fed to emergency oxygen system <NUM> and/or air distribution subsystem <NUM> based on the oxygen content (step <NUM>).

<FIG> is a flow chart illustrating another method <NUM> of supplying oxygen enriched air to an aircraft in an illustrative example not falling under the scope of the appended claims. Steps <NUM>-<NUM> of method <NUM> are similar to that described above in <FIG>. When pressure sensor <NUM> detects a cabin decompression event on aircraft <NUM>, manifold <NUM> feeds the oxygen enriched air <NUM> from air separator <NUM> to air distribution subsystem <NUM> (step <NUM>). Thus, the oxygen concentration in cabin <NUM> may be enriched by the oxygen enriched air <NUM> during a cabin decompression event. Step <NUM> may be performed concurrently with step <NUM> of method <NUM>, or may be performed in place of step <NUM>.

Methods <NUM>-<NUM> advantageously use the "waste" oxygen from air separator <NUM> for emergency oxygen system <NUM> and/or air distribution subsystem <NUM>. Thus, traditional chemical oxygen generators and gaseous manifolds may not be needed for a cabin decompression event. Also, methods <NUM>-<NUM> may use the "waste" oxygen from air separator <NUM> to supplement the air delivered to cabin <NUM> by air distribution subsystem <NUM> to improve air quality in aircraft <NUM>.

Any of the various elements shown in the figures or described herein may be implemented as hardware, software, firmware, or some combination of these.

Claim 1:
An aircraft (<NUM>) comprising
an oxygen supply subsystem (<NUM>) configured to supply oxygen to a cockpit and/or cabin of the aircraft, the oxygen supply subsystem comprising: an emergency oxygen system (<NUM>) including a pressure sensor (<NUM>) configured to detect a cabin decompression event on the aircraft; an environmental control system ECS (<NUM>) including an environmental control unit ECU (<NUM>) and an air distribution subsystem (<NUM>) configured to distribute conditioned air from the ECU to the cockpit and/or cabin of the aircraft;
an air separator (<NUM>) configured to receive a pressurized air stream, to separate the pressurized air stream into oxygen enriched air and an inert gas;
a controller (<NUM>) arranged to receive input from the pressure sensor and an oxygen sensor configured to measure oxygen content at the oxygen supply subsystem; and
a manifold (<NUM>) coupled to the controller, wherein in response to the cabin decompression event, the controller is configured to control the manifold responsive to input from the pressure sensor and the oxygen sensor to feed the oxygen enriched air from the air separator to both the emergency oxygen system and the air distribution subsystem.