Patent Description:
An air separation module (ASM) is a core element of a flammability reduction system (FRS) onboard an aircraft. The ASM separates oxygen from air to supply nitrogen-enriched-air into the ullage of the fuel tanks of the aircraft. The ASM is a costly component of the FRS. Additionally, the downtime for replacement of an ASM is substantially higher than other maintenance work associated with the FRS. Further, long-haul aircraft usually have multiple ASMs. This results in substantial maintenance cost and hours of downtime when the ASM units need to be replaced. <CIT>, in accordance with its abstract, states an inerting fuel system for inerting fuel tanks that includes an inlet passage to receive inlet air, air separation modules to separate oxygen from the inlet air when received, and air separation module valves coupled between the air inlet passage and the air separation modules. The air separation module valves are associated with the air separation modules such that opening of one of the air separation module valves passes a portion of inlet air from the air inlet passage to the air separation module associated with that air separation module valve. A controller selectively opens the air separation module valves such that each of the air separation modules receives a substantially equal level of wear. <CIT>, in accordance with its abstract, states a generator of inert gas from an airflow, in an inerting system for at least one aircraft fuel tank. The generator includes a system with an air inlet and means for distributing the airflow to a plurality of air separation modules arranged in parallel on the air system to deplete oxygen in the air and generate a nitrogen-enriched inert gas at the outlet. The generator also includes a programed control unit for the distribution means to selectively supply air to a single, a portion or all of the air separation modules, depending on the flight phase of the aircraft.

A method for air separation module management according to claim <NUM> is provided. The method for air separation module management includes determining an amount of nitrogen-enriched-air to be supplied to each fuel tank of a plurality of fuel tanks of an aircraft and evaluating a status and usage of each air separation module of a plurality of air separation modules onboard the aircraft. The method also includes determining an optimal distribution of workload among the plurality of air separation modules based on the amount of the nitrogen-enriched-air to be supplied to each fuel tank and the status and usage of each air separation module. The method further includes regulating a valve associated with each air separation module or a group of air separation modules based on the optimal distribution of workload to each air separation module.

A flammability reduction system onboard an aircraft according to claim <NUM> is provided. The flammability reduction system includes a plurality of air separation modules connected in parallel. The plurality of air separation modules are configured to selectively supply nitrogen-enriched-air to each fuel tank of a plurality of fuel tanks of the aircraft. The flammability reduction system also includes an air separation module (ASM) management system. The air separation management system includes an ASM management module configured to determine an optimal distribution of workload among the plurality of air separation modules based on an amount of nitrogen-enriched-air to be supplied to each fuel tank and a status and usage of each air separation module. The air separation management system also includes a valve associated with each air separation module or a group of the air separation modules of the plurality of air separation modules. Each of the valves is regulated based on the optimal distribution of the workload among the air separation modules.

The air separation module management system includes a controller for air separation module management. The controller includes a processor and a memory associated with the processor. The memory includes computer-readable program instructions that, when executed by the processor causes the processor to perform a set of functions including determining an amount of nitrogen-enriched-air to be supplied to each fuel tank of a plurality of fuel tanks of an aircraft and evaluating a status and usage of each air separation module of a plurality of air separation modules. The set of functions also include determining an optimal distribution of workload among the plurality of air separation modules based on the amount of the nitrogen-enriched-air to be supplied to each fuel tank and the status and usage of each separation module. The set of functions further include regulating a valve associated with each air separation module or a group of air separation modules based on the optimal distribution of workload among each air separation module.

Determining the amount of the nitrogen-enriched-air to be supplied to each fuel tank includes determining an amount of oxygen in nitrogen-enriched-air flowing from the plurality of air separation modules.

Determining the amount of the nitrogen-enriched-air to be supplied to each fuel tank includes determining an amount of oxygen in the nitrogen-enriched-air flowing from the plurality of air separation modules and determining an amount of oxygen in conditioned air being supplied to the plurality of air separation modules from an air supply control system.

In accordance with an example and any of the preceding examples, wherein determining the amount of the nitrogen-enriched-air to be supplied to each fuel tank includes determining an amount of oxygen in the nitrogen-enriched-air flowing individually from each air separation module of the plurality of air separation modules.

In accordance with an example and any of the preceding examples, wherein determining the amount of the nitrogen-enriched-air to be supplied to each fuel tank includes determining an amount of oxygen in the nitrogen-enriched-air flowing individually from each air separation module of the plurality of air separation modules and determining an amount of oxygen in conditioned air being supplied to the plurality of air separation modules from an air supply control system.

In accordance with an example and any of the preceding examples, wherein determining the amount of the nitrogen-enriched-air to be supplied to each fuel tank includes determining a need of the nitrogen-enriched-air in ullage of each fuel tank.

In accordance with an example and any of the preceding examples, wherein determining the need of the nitrogen-enriched-air in the ullage of each fuel tank includes using a set of parameters including a phase of flight of the aircraft, an outside air temperature, an altitude of the aircraft, fuel tank usage, and engine settings.

In accordance with an example and any of the preceding examples, wherein determining the amount of the nitrogen-enriched-air to be supplied to each fuel tank includes using an amount of oxygen in nitrogen-enriched-air flowing from the plurality of air separation modules and a set of parameters including a phase of flight of the aircraft, an outside air temperature, an altitude of the aircraft, fuel tank usage, and engine settings.

In accordance with an example and any of the preceding examples, further including generating data corresponding to the amount of nitrogen-enriched-air to be supplied to each fuel tank based on a set of parameters including a phase of flight of the aircraft, an outside air temperature, an altitude of the aircraft, fuel tank usage, engine settings, an amount of oxygen in the nitrogen-enriched-air flowing from the plurality of air separation modules, and ullage of each fuel tank.

In accordance with an example and any of the preceding examples, wherein evaluating the status and the usage of each air separation module includes monitoring an amount of usage of each air separation module of the plurality of air separation modules; evaluating the status and usage of each air separation module using a benchmark performance database; and generating data corresponding to the status and usage of each air separation module. The data is used in the determining the optimal distribution of workload among each air separation module.

In accordance with an example and any of the preceding examples, wherein determining the optimal distribution of workload among the plurality of air separation modules includes ranking each air separation module of the plurality of air separation modules based on an amount of prior usage; and using a selected air separation module or a combination of selected air separation modules according to a strategy for the optimal distribution of workload among the plurality of air separation modules.

In accordance with an example and any of the preceding examples, wherein a lower ranking of a particular air separation module corresponds to a lower amount of prior usage of the particular air separation module, and wherein the strategy for the optimal distribution of workload among the plurality of air separation modules includes using the selected air separation module or the combination of selected air separation modules with the lower ranking or rankings before the air separation modules with the higher rankings to balance an amount of usage among the air separation modules.

In accordance with an example and any of the preceding examples, wherein determining the optimal distribution of workload among the plurality of air separation modules includes using particular air separation modules of the plurality of air separation modules having a lower amount of usage before other air separation modules having a higher amount of usage to balance an amount of usage among the air separation modules.

Further including a sensor configured to determine an amount of oxygen in the nitrogen-enriched-air being supplied to the fuel tanks.

In accordance with an example and any of the preceding examples, further including a sensor associated with each air separation module. Each sensor is configured to determine an amount of oxygen in the nitrogen-enriched-air flowing from the associated air separation module.

Further including an output sensor configured to determine an amount of oxygen in the nitrogen-enriched-air flowing from the plurality of air separation modules; and an input sensor configured to determine an amount of oxygen in the conditioned air being supplied to the plurality of air separation modules from an air supply control system.

In accordance with an example and any of the preceding examples, further including downloading in-service data associated with each of the plurality of air separation modules to an application off-board the aircraft for analyzing the in-service data; and analyzing the in-service data according to a strategy for optimal distribution of workload among the air separation modules.

The embodiments described herein enable a controlled management of a set of air separation modules that are components of a flammability reduction system onboard an aircraft or other vehicle. The embodiments described herein also track usage of the air separation modules and ensure wear of all the air separation modules according to a predetermined schedule or pattern of wear or use to optimize their usage and increase their lifespan. In accordance with an example, the predetermined schedule or pattern of wear or use is parallel wear or use of the air separation modules. Other patterns of wear or use are used in other examples using active control for example. The system for air separation module management also enables system failure diagnostics and/or prognostics by using a benchmark performance database that includes a reference digital-twin of each air separation module. In some examples, the system failure diagnostics and/or prognostics are performed on-board the aircraft. Some examples include an on-board reference digital model hosted in a nitrogen-enriched-air (NEA) controller or other on-board device. In other examples, the system failure diagnostics and/or prognostics are performed off-board. These examples include an off-board application for analyzing air separation module (ASM) in-service data during turn-around time of the aircraft on a certain regular basis.

The system and method for ASM management monitors ASM performance using one or more oxygen sensor and controls utilization of the air separation modules using upstream or downstream valves as described herein. The valves are regulatable to optimize performance of each air separation module and usage according to the performances and usages of the other air separation modules onboard to increase the lifetime of all the air separation modules, while controlling their individual degradations. Changes in the responses of the valves over time establish a health and performance assessment method for the air separation modules, thus facilitating a conditional-based maintenance plan that will recommend to conduct replacement of a particular air separation module at the right time, reducing downtime of maintenance tasks if a single air separation module needs to be replaces rather than an entire set. Additionally, monitoring the performance of the air separation modules using the benchmark performance database improves the health and performance assessment of the entire flammability reduction system.

<FIG> is a block schematic diagram of an example of a flammability reduction system <NUM> onboard an aircraft <NUM> in accordance with an example of the present disclosure. The flammability reduction system <NUM> includes a plurality of air separation modules <NUM> connected in parallel. The flammability reduction system <NUM> receives air from an air supply control system <NUM>. The air supply control system <NUM> is configured to supply conditioned air <NUM> to the plurality of air separation modules <NUM>. In some examples, the air supply control system <NUM> is configured to withdraw bleed air from the engines and then regulates the pressure and temperature of the air. The plurality of air separation modules <NUM> are configured to selectively supply nitrogen-enriched-air <NUM> to each fuel tank <NUM> of a plurality of fuel tanks <NUM> of the aircraft <NUM>. In the example in <FIG>, the exemplary flammability reduction system <NUM> includes five air separation modules <NUM> (referenced as 106a-106e). In other examples, the flammability reduction system <NUM> will have less than five air separation modules <NUM> or more than five air separation modules <NUM> depending upon the number and size of the fuel tanks and engines of a particular aircraft.

The flammability reduction system <NUM> also includes a system <NUM> for air separation module (ASM) management or ASM management system <NUM>. The ASM management system <NUM> includes an ASM management module <NUM> configured to determine an optimal distribution of workload <NUM> among the plurality of air separation modules <NUM> based on an amount of nitrogen-enriched-air <NUM> to be supplied to each fuel tank <NUM> and a status and usage of each air separation module <NUM>.

The ASM management system <NUM> also includes a valve <NUM> associated with each air separation module <NUM> or a group of the air separation modules <NUM> (as illustrated in the example of <FIG>) of the plurality of air separation modules <NUM>. Each of the valves <NUM> is regulated based on the optimal distribution of workload <NUM> among the air separation modules <NUM>. In the example in <FIG>, a flow rate of conditioned air <NUM> into each air separation module <NUM> is controlled by individually regulating the valve <NUM> associated with each air separation module <NUM> or group of air separation modules <NUM> (<FIG>). In the example in <FIG>, the valve <NUM> associated with each air separation module <NUM> or group of air separation modules <NUM> (<FIG>) is upstream from the air separation modules <NUM>. In the example in <FIG>, the valve <NUM> associated with each air separation module <NUM> is downstream from the air separation modules <NUM>. In other examples, valves <NUM> associated with a group of air separation modules <NUM> similar to that illustrated in <FIG> are downstream from the air separation modules <NUM>.

The flammability reduction system <NUM> also includes a controller <NUM> and a flow control valve <NUM>. The controller <NUM> is configured to regulate the flow control valve <NUM> to control an amount of nitrogen-enriched-air <NUM> supplied to the fuel tanks <NUM>.

In some examples, the system <NUM> for air separation module (ASM) management includes a processor <NUM> and a memory <NUM> associated with the processor <NUM>. The memory <NUM> includes computer-readable program instructions <NUM> that, when executed by the processor <NUM> causes the processor <NUM> to perform a set of functions <NUM> for air separation module management as described in more detail with reference to method <NUM> described with reference to <FIG>. In accordance with an example, the set of functions <NUM> include but are not necessarily limited to determining an amount of an nitrogen-enriched-air <NUM> to be supplied to each fuel tank <NUM> of a plurality of fuel tanks <NUM> of an aircraft <NUM>; evaluating a status and usage of each air separation module <NUM> of a plurality of air separation modules <NUM>; determining an optimal distribution of workload <NUM> among the plurality of air separation modules <NUM> based on the amount of the nitrogen-enriched-air <NUM> to be supplied to each fuel tank <NUM> and the status and usage of each air separation module <NUM>; and regulating a valve <NUM> associated with each air separation module <NUM> or a group of air separation modules <NUM> based on the optimal distribution of workload <NUM> among each air separation module <NUM>.

In the example in <FIG>, the ASM management system <NUM> includes the controller <NUM> and the controller <NUM> includes the processor <NUM> and the memory <NUM>. The set of functions <NUM> include the ASM management module <NUM>. As previously described, the ASM management module <NUM> is configured to determine the optimal distribution of workload <NUM> among the plurality of air separation modules <NUM> based on an amount of nitrogen-enriched-air <NUM> to be supplied to each fuel tank <NUM> and a status and usage of each air separation module <NUM>. The controller <NUM> is configured to individually or separately control regulation of each of the valves <NUM> based on the optimal distribution of workload <NUM> among the air separation modules <NUM>.

The ASM management module <NUM> is configured to determine the optimal distribution of workload <NUM> using a benchmark performance database <NUM>. The status and usage of each air separation module <NUM> are evaluated using the benchmark performance database <NUM>. The benchmark performance database <NUM> includes an ASM reference model <NUM> or reference digital-twin of each air separation module <NUM>. The status and usage of each air separation module <NUM> are evaluated by the ASM management module <NUM> using the ASM reference model <NUM> of each air separation module <NUM> in the benchmark performance database <NUM> as described in more detail herein.

In some examples, the system <NUM> for air separation module management includes an off-board application <NUM> for analyzing air separation module in-service data. The off-board application <NUM> is an application that is off-board the aircraft <NUM>. The application <NUM> for analyzing air separation module in-service data is configured to evaluate status and usage of each air separation module <NUM> using a benchmark performance database similar to benchmark performance database <NUM>. The off-board application <NUM> for analyzing air separation module in-service data performs the analysis during turn-around time of the aircraft <NUM> on a certain regular basis.

The flammability reduction system <NUM> also includes an output sensor <NUM> configured to determine an amount of oxygen in the nitrogen-enriched-air <NUM> being supplied to the fuel tanks <NUM>. The output sensor <NUM> is positioned downstream from the air separation modules <NUM>.

The flammability reduction system <NUM> includes an output sensor <NUM> configured to determine an amount of oxygen in the nitrogen-enriched-air <NUM> flowing from the plurality of air separation modules <NUM> and an input sensor <NUM> configured to determine an amount of oxygen in the conditioned air <NUM> being supplied to the plurality of air separation modules <NUM> from the air supply control system <NUM>.

<FIG> is a block schematic diagram of another example of a flammability reduction system <NUM> onboard an aircraft <NUM> in accordance with the present disclosure. The flammability reduction system <NUM> includes an ASM management system <NUM>. The ASM management system <NUM> is substantially the same as the ASM management system <NUM> described with reference to <FIG>. In the example in <FIG>, the flammability reduction system <NUM> and/or ASM management system <NUM> include an output sensor <NUM> associated with each air separation module <NUM>. Each output sensor <NUM> is configured to determine an amount of oxygen in the nitrogen-enriched-air <NUM> flowing from the associated air separation module <NUM>. Similar to that previously described, the controller <NUM> or ASM management module <NUM> embodied in the controller <NUM> is configured to determine an optimal distribution of workload <NUM> (<FIG>) among the plurality of air separation modules <NUM> based on the amount of nitrogen-enriched-air <NUM> to be supplied to each fuel tank <NUM> and based on a status and usage of each air separation module <NUM>.

The flammability reduction system <NUM> also includes an input sensor <NUM> configured to determine an amount of oxygen in the conditioned air <NUM> being supplied to the plurality of air separation modules <NUM> from the air supply control system <NUM>.

<FIG> is a block schematic diagram of another example of a flammability reduction system <NUM> onboard an aircraft <NUM> in accordance with the present disclosure. The flammability reduction system <NUM> includes an ASM management system <NUM> that is substantially the same as the ASM management system <NUM> described with reference to <FIG>. The flammability reduction system <NUM> and/or ASM management system <NUM> include a valve <NUM> that regulates conditioned air <NUM> flowing into one or a group of air separation modules <NUM>. The valves <NUM> are controlled or regulated by the controller <NUM> based on the optimal distribution of workload <NUM> to each air separation module <NUM>. In other examples, the configuration of valves <NUM> in the example in <FIG> is also usable with the flammability reduction systems <NUM> and <NUM> and ASM management systems <NUM> and <NUM> in <FIG> and <FIG>.

<FIG> is a block schematic diagram of a further example of a flammability reduction system <NUM> onboard an aircraft <NUM> in accordance with the present disclosure. The flammability reduction system <NUM> and the ASM management system <NUM> are substantially the same as the flammability reduction system <NUM> and ASM management system <NUM> in <FIG>. In the exemplary flammability reduction system <NUM> in <FIG>, the valve <NUM> associated with each air separation module <NUM> is downstream from the air separation module <NUM>. Similar to that previously described, each valve <NUM> is regulated by the controller <NUM> or ASM management module <NUM> embodied in the controller <NUM> based on the optimal distribution of workload <NUM> among the air separation modules <NUM>. In other examples, the valves <NUM> are associated with one or a group of air separation modules <NUM> similar to the example in <FIG> except the valves <NUM> are downstream from the air separation modules <NUM>.

<FIG> is a flow chart of an example of a method <NUM> for operating a flammability reduction system and air separation module management in accordance with an example of the present disclosure. In some examples, the method <NUM> is embodied in and performed by the components of the flammability reduction systems <NUM>, <NUM>, <NUM>, or <NUM> as described with reference to <FIG>. The method <NUM> also includes an exemplary method <NUM> for air separation module management that is embodied in and performed by any of the ASM management systems <NUM>, <NUM>, <NUM>, or <NUM> in <FIG>. In some examples, the exemplary method <NUM> is embodied in the ASM management module <NUM> (<FIG>).

In accordance with some examples, the method <NUM> includes at least determining <NUM> an amount of nitrogen-enriched-air <NUM> to be supplied to each fuel tank <NUM> of a plurality of fuel tanks <NUM> of an aircraft <NUM>; evaluating <NUM> a status and usage of each air separation module <NUM> of a plurality of air separation modules <NUM> onboard the aircraft <NUM>; determining <NUM> an optimal distribution of workload <NUM> among the plurality of air separation modules <NUM> based on the amount of the nitrogen-enriched-air <NUM> to be supplied to each fuel tank <NUM> and the status and usage of each air separation module <NUM>; and regulating <NUM> a valve <NUM> associated with each air separation module <NUM> or a group of air separation modules <NUM> based on the optimal distribution of workload <NUM> to each air separation module <NUM>.

In block <NUM>, the flammability reduction system (FRS) <NUM>, <NUM>, <NUM>, or <NUM> is active. In block <NUM>, in some examples, bleed air from at least one engine of the aircraft <NUM> is extracted by the air supply control system (ASCS) <NUM>. In other examples, air is extracted from other sources, for example, outside air. In block <NUM>, the ASCS <NUM> regulates the pressure and temperature of the bleed air or air from another source. In block <NUM>, conditioned air <NUM> from the ASCS <NUM> is supplied to the flammability reduction system (FRS) <NUM>, <NUM>, <NUM>, or <NUM>. In block <NUM>, the flammability reduction system (FRS) <NUM>, <NUM>, <NUM>, or <NUM> distributes the air through the air separation modules <NUM> that are selectively active by regulating <NUM> a valve <NUM> associated with each air separation module <NUM> or a group of air separation modules <NUM> (<FIG>) based on the optimal distribution of workload <NUM> between each air separation module <NUM>. In block <NUM>, nitrogen-enriched-air is supplied to the fuel tanks ullage.

In block <NUM>, the method <NUM> includes determining an amount of nitrogen-enriched-air <NUM> to be supplied to each fuel tank <NUM> of the plurality of fuel tanks <NUM> of the aircraft <NUM>. A flow chart of an example of a method <NUM> for determining an amount or need of nitrogen-enriched-air <NUM> to be supplied to each fuel tank <NUM> will be described in more detail with reference to <FIG>.

In block <NUM>, the method <NUM> includes evaluating a status and usage of each air separation module <NUM> of the plurality of air separation modules <NUM> onboard the aircraft <NUM>. A flow chart of an example of a method <NUM> for evaluating a status and usage of each air separation module <NUM> will be described in more detail with reference to <FIG>.

In block <NUM>, the method <NUM> includes determining an optimal distribution of workload <NUM> among the plurality of air separation modules <NUM> based on the amount of the nitrogen-enriched-air <NUM> to be supplied to each fuel tank <NUM> and the status and usage of each air separation module <NUM>. A flow chart of an example of a method <NUM> for determining an optimal distribution of workload <NUM> among a plurality of air separation modules <NUM> will be described in more detail with reference to <FIG>. In accordance with an example, the optimal distribution of workload <NUM> is determined using an optimization strategy, e.g., a cost function is minimized. In an example, an amount of usage among the air separation modules <NUM> is balanced. In another example, two groups of air separation modules <NUM> are each balanced based on an amount of usage or ranking. In this example, the aircraft <NUM> always has a group of air separation modules <NUM> in a more degraded state and another group of air separation modules <NUM> in a less degraded state. When the group of degraded air separation modules <NUM> reaches a usage level for replacement, the aircraft <NUM> still has the other group of air separation modules <NUM> in a less degraded or better, usable state. This prevents the situation of all air separation modules <NUM> having to be replaced at the same time, resulting in a longer maintenance downtime. Therefore, there is no risk of having all air separation modules <NUM> degraded and needing replacement at the same time.

In block <NUM>, the method <NUM> includes regulating a valve <NUM> associated with each air separation module <NUM> or a group of air separation modules <NUM> (<FIG>) based on the optimal distribution of workload <NUM> to each air separation module <NUM>.

<FIG> is a flow chart of an example of a method <NUM> for determining an amount or need of nitrogen-enriched-air <NUM> to be supplied to each fuel tank <NUM> in accordance with an example of the present disclosure. In accordance with some examples, the method <NUM> is used for block <NUM> in <FIG>. In block <NUM>, determining the amount of the nitrogen-enriched-air <NUM> to be supplied to each fuel tank <NUM> includes determining a need of the nitrogen-enriched-air <NUM> in ullage of each fuel tank <NUM>. Determining the need of the nitrogen-enriched-air <NUM> in the ullage of each fuel tank <NUM> includes using a set of parameters. The set of parameters include but are not necessarily limited to a phase of flight of the aircraft <NUM>, an outside air temperature, an altitude of the aircraft <NUM>, fuel tank usage, and engine settings.

In block <NUM>, the method <NUM> includes determining an amount of oxygen in nitrogen-enriched-air <NUM> flowing from the plurality of air separation modules <NUM>. In accordance with an example, determining the amount of oxygen in the nitrogen-enriched-air <NUM> flowing from the air separation modules <NUM> includes using a single output sensor <NUM> as illustrated in <FIG>.

In accordance with another example, determining the amount of the nitrogen-enriched-air <NUM> to be supplied to each fuel tank <NUM> in block <NUM> includes determining an amount of oxygen in the nitrogen-enriched-air flowing individually from each air separation module <NUM> of the plurality of air separation modules <NUM>. Determining the amount of oxygen in the nitrogen-enriched-air flowing individually from each air separation module <NUM> includes using an output sensor <NUM> associated with each air separation module <NUM> as illustrated in the example in <FIG>.

In block <NUM>, the method <NUM> optionally includes determining an amount of oxygen in conditioned air <NUM> from an air supply control system <NUM>. In accordance with an example, determining the amount of oxygen in the conditioned air <NUM> from the air supply control system <NUM> includes using at least one input sensor <NUM> upstream from the air separation modules <NUM> as illustrated in the example in <FIG>.

In accordance with another example, determining the amount of the nitrogen-enriched-air <NUM> to be supplied to each fuel tank <NUM> includes determining an amount of oxygen in the nitrogen-enriched-air <NUM> flowing from the plurality of air separation modules <NUM> and determining an amount of oxygen in conditioned air being supplied to the plurality of air separation modules <NUM> from an air supply control system <NUM>.

In accordance with a further example, determining the amount of the nitrogen-enriched-air <NUM> to be supplied to each fuel tank <NUM> includes determining an amount of oxygen in the nitrogen-enriched-air <NUM> flowing individually from each air separation module <NUM> of the plurality of air separation modules <NUM> and determining an amount of oxygen in conditioned air <NUM> being supplied to the plurality of air separation modules <NUM> from an air supply control system <NUM>. In this example, determining the amount of oxygen in the nitrogen-enriched-air <NUM> flowing individually from each air separation module <NUM> includes using an output sensor <NUM> associated with each air separation module <NUM> as illustrated in the example in <FIG>. Determining the amount of oxygen in the conditioned air <NUM> being supplied to the air separation modules <NUM> includes using at least a single input sensor <NUM> as illustrated in the example in <FIG>.

In block <NUM>, determining an amount of the nitrogen-enriched-air <NUM> to be supplied to each fuel tank <NUM> includes using an amount of oxygen in the nitrogen-enriched-air <NUM> flowing from the plurality of air separation modules <NUM> and a set of parameters. The set of parameters include but are not necessarily limited to a phase of flight of the aircraft <NUM>, an outside air temperature, an altitude of the aircraft <NUM>, fuel tank usage, and engine settings. Optionally, an amount of oxygen in the conditioned air <NUM> from the air supply control system <NUM> is also used in determining an amount of the nitrogen-enriched-air <NUM> to be supplied to each fuel tank <NUM>. The distribution of nitrogen-enriched-air <NUM> among the fuel tanks <NUM> is performed based on a quantity of fuel in each fuel tank <NUM> and fuel tank pressure readings.

In block <NUM>, the method <NUM> further includes generating data corresponding to the amount of nitrogen-enriched-air <NUM> to be supplied to each fuel tank <NUM> based on the set of parameters including at least a phase of flight of the aircraft, an outside air temperature, an altitude of the aircraft, fuel tank usage, engine settings, an amount of oxygen in the nitrogen-enriched-air <NUM> flowing from the plurality of air separation modules <NUM>, optionally an amount of oxygen in the conditioned air <NUM>, and ullage of each fuel tank <NUM>.

<FIG> is a flow chart of an example of a method <NUM> for evaluating a status and usage of each air separation module <NUM> in accordance with an example of the present disclosure. In some examples, the method <NUM> is used for the block <NUM> in <FIG>. In block <NUM>, evaluating the status and the usage of each air separation module <NUM> includes monitoring an amount of usage of each air separation module <NUM> of the plurality of air separation modules <NUM>. In some examples, monitoring an amount of usage of each air separation module <NUM> includes monitoring or tracking operation hours of each air separation module <NUM>. The method <NUM> also includes storing the amount of usage of each air separation module <NUM> in a benchmark performance database <NUM>.

In block <NUM>, the exemplary method <NUM> includes determining an amount of degradation of each air separation module <NUM> based on the amount of prior usage of each air separation module <NUM>. Referring also to <FIG> is a graph <NUM> illustrating performance (P) or health versus operation time (t) over a serviceable life of an exemplary air separation module <NUM>. As illustrated in <FIG>, the performance or health of an exemplary air separation module <NUM> degrades approximately exponentially over operation time of the air separation module <NUM>.

In block <NUM>, the exemplary method <NUM> includes evaluating the status and usage of each air separation module <NUM> using a benchmark performance database <NUM>. The status is defined as the efficiency or operational effectiveness of the air separation module <NUM> in filtering oxygen from the conditioned air <NUM>.

In accordance with a first example, the benchmark performance database <NUM> is configured to track the efficiency of each air separation module <NUM> or group of air separation modules <NUM> as illustrated in <FIG> as a function of time which could be, for example, the number of flight hours, number of cycles, or the number of flights after installation of the air separation module <NUM> on the aircraft <NUM>. The efficiency is tracked by comparing the oxygen concentration in the conditioned air <NUM>, measured using an upstream or input sensor <NUM>, to the oxygen concentration in the nitrogen-enriched-air <NUM>, measured using a downstream or output sensor <NUM> (<FIG>) or output sensors <NUM> (<FIG>), after the air separation module <NUM> or group of air separation modules <NUM>. In an example where the ASM management system <NUM> does not include an upstream or input sensor <NUM>, a position of the flow control valve <NUM> is compared for two similar flight profiles, e.g., if on average the position of the valve <NUM> is more open, that is an indication that the air separation module <NUM> is becoming less efficient.

In accordance with a second example, the benchmark performance database <NUM> includes an ASM reference model <NUM> associated with each air separation module <NUM> that serves as a benchmark for tracking the efficiency of the associated air separation module <NUM>. The ASM reference model <NUM> is based on empirical air separation module performance results. Operation time of the air separation module <NUM> is compared to the ASM reference model <NUM> to track the efficiency or performance/health index as illustrated in <FIG>.

Both examples of using the benchmark performance database <NUM> can be leveraged to perform predictive maintenance. The first example predicts maintenance is coming due when the efficiency of the air separation module <NUM> falls below a predetermined level. The second example helps predict maintenance is coming due when the performance between in-service or actual air separation module <NUM> exceeds a preset threshold according to the associated ASM reference model <NUM>.

In block <NUM>, the method <NUM> includes generating data corresponding to the status and usage of each air separation module <NUM>. The data is used in the determining the optimal distribution of workload <NUM> among each air separation module <NUM> in block <NUM> of <FIG>.

<FIG> is a flow chart of an example of a method <NUM> for determining an optimal distribution of workload <NUM> among a plurality of air separation modules <NUM> in accordance with an example of the present disclosure. In some examples, the method <NUM> is used for the block <NUM> in <FIG>.

In block <NUM>, the method <NUM> includes determining the optimal distribution of workload <NUM> among the air separation modules <NUM> using data corresponding to the status and usage of each air separation module <NUM>, e.g., using the method <NUM>.

In accordance with an example, the method <NUM> includes downloading in-service data associated with each of the plurality of air separation modules <NUM> to an application <NUM> off-board the aircraft <NUM> for analyzing the in-service data; and analyzing the in-service data according to a strategy for optimal distribution of workload <NUM> among the air separation modules <NUM>.

In block <NUM>, the method <NUM> includes ranking each air separation module <NUM> of the plurality of air separation modules <NUM> based on an amount of prior usage. The method <NUM> also includes using a selected air separation module <NUM> or a combination of selected air separation modules <NUM> according to a strategy for optimal distribution of the workload <NUM> among the air separation modules <NUM>.

In accordance with an example, a lower ranking of a particular air separation module <NUM> corresponds to a lower amount of prior usage of the particular air separation module <NUM>. The strategy for the optimal distribution of workload <NUM> among the plurality of air separation modules <NUM> includes using the selected air separation module <NUM> or the combination of selected air separation modules <NUM> with the lower ranking or rankings before the air separation modules <NUM> with the higher rankings to balance an amount of usage among the air separation modules <NUM>.

In accordance with another example, determining the optimal distribution of workload <NUM> among the plurality of air separation modules <NUM> includes using particular air separation modules <NUM> of the plurality of air separation modules <NUM> having a lower amount of usage before other air separation modules <NUM> having a higher amount of usage to balance an amount of usage among the air separation modules <NUM>.

In block <NUM>, the method <NUM> includes using the optimal distribution of workload <NUM> among the air separation modules <NUM> to regulate a valve <NUM> associated with each air separation module <NUM> or group of air separation modules <NUM> as described with reference to block <NUM> in <FIG>.

The subject disclosure may be a system, a method, and/or a computer program product. In some examples, the set of functions are embodied on a computer program product, such as memory or other computer program product as described herein. The computer program product may include a computer-readable storage medium (or media) having computer-readable program instructions thereon for causing a processor to carry out aspects of the subject disclosure.

The computer-readable storage medium can be a tangible device that can retain and store instructions for use by an instruction execution device. The computer-readable storage medium may be, for example, but is not limited to, an electronic storage device, a magnetic storage device, an optical storage device, an electromagnetic storage device, a semiconductor storage device, or any suitable combination of the foregoing. A non-exhaustive list of more specific examples of the computer-readable storage medium includes the following: a portable computer diskette, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or Flash memory), a static random access memory (SRAM), a portable compact disc read-only memory (CD-ROM), a digital versatile disk (DVD), a memory stick, a floppy disk, a mechanically encoded device such as punch-cards or raised structures in a groove having instructions recorded thereon, and any suitable combination of the foregoing. A computer-readable storage medium, as used herein, is not to be construed as being transitory signals per se, such as radio waves or other freely propagating electromagnetic waves, electromagnetic waves propagating through a waveguide or other transmission media (e.g., light pulses passing through a fiber-optic cable), or electrical signals transmitted through a wire.

Computer-readable program instructions described herein can be downloaded to respective computing/processing devices from a computer-readable storage medium or to an external computer or external storage device via a network, for example, the Internet, a local area network, a wide area network and/or a wireless network. A network adapter card or network interface in each computing/processing device receives computer-readable program instructions from the network and forwards the computer-readable program instructions for storage in a computer-readable storage medium within the respective computing/processing device.

Computer-readable program instructions for carrying out operations of the subject disclosure may be assembler instructions, instruction-set-architecture (ISA) instructions, machine instructions, machine dependent instructions, microcode, firmware instructions, state-setting data, or either source code or object code written in any combination of one or more programming languages, including an object oriented programming language such as Smalltalk, C++ or the like, and conventional procedural programming languages, such as the "C" programming language or similar programming languages. In some examples, electronic circuitry including, for example, programmable logic circuitry, field-programmable gate arrays (FPGA), or programmable logic arrays (PLA) may execute the computer-readable program instructions by utilizing state information of the computer-readable program instructions to personalize the electronic circuitry, in order to perform aspects of the subject disclosure.

Aspects of the subject disclosure are described herein with reference to flowchart illustrations and/or block diagrams of methods, apparatus (systems), and computer program products according to examples of the disclosure. It will be understood that each block of the flowchart illustrations and/or block diagrams, and combinations of blocks in the flowchart illustrations and/or block diagrams, can be implemented by computer-readable program instructions.

The flowchart and block diagrams in the Figures illustrate the architecture, functionality, and operation of possible implementations of systems, methods, and computer program products according to various examples of the subject disclosure.

The terminology used herein is for the purpose of describing particular examples only and is not intended to be limiting of examples of the disclosure, insofar as they fall within the scope of the appended claims. It will be further understood that the terms "include," "includes," "comprises" and/or "comprising," when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof.

The corresponding structures, materials, acts of all means or step plus function elements in the claims below are intended to include any structure, material, or act for performing the function in combination with other claimed elements as specifically claimed. The description of the present examples has been presented for purposes of illustration and description, but is not intended to be exhaustive or limited to examples in the form disclosed. Many modifications and variations will be apparent to those of ordinary skill in the art without departing from the scope and spirit of examples.

Claim 1:
A method (<NUM>) for air separation module management, the method (<NUM>) comprising:
determining (<NUM>) an amount of nitrogen-enriched-air (<NUM>) to be supplied to each fuel tank (<NUM>) of a plurality of fuel tanks (<NUM>) of an aircraft (<NUM>), wherein determining (<NUM>) the amount of the nitrogen-enriched-air (<NUM>) to be supplied to each fuel tank (<NUM>) comprises:
determining (<NUM>) an amount of oxygen in nitrogen-enriched-air (<NUM>) flowing from the plurality of air separation modules (<NUM>); and determining (<NUM>) an amount of oxygen in conditioned air (<NUM>) being supplied to the plurality of air separation modules (<NUM>) from an air supply control system (<NUM>);
evaluating (<NUM>) a status and usage of each air separation module (<NUM>) of a plurality of air separation modules (<NUM>) onboard the aircraft (<NUM>);
determining (<NUM>) an optimal distribution of workload among the plurality of air separation modules (<NUM>) based on the amount of the nitrogen-enriched-air (<NUM>) to be supplied to each fuel tank (<NUM>) and the status and usage of each air separation module (<NUM>); and
regulating (<NUM>) a valve (<NUM>) associated with each air separation module (<NUM>) or a group of air separation modules (<NUM>) based on the optimal distribution of workload to each air separation module (<NUM>).