Patent ID: 12240623

DETAILED DESCRIPTION

Reference will now be made in detail to embodiments of the present disclosure, examples of which are described herein and illustrated in the accompanying drawings. While the present disclosure will be described in conjunction with embodiments and/or examples, it will be understood that they are not intended to limit the present disclosure to these embodiments and/or examples. On the contrary, the present disclosure is intended to cover alternatives, modifications, and equivalents.

In embodiments, such as generally illustrated inFIG.1, an aircraft fuel tank inerting system10may include an inert air assembly12, one or more main fuel tanks14,16,18(e.g., a left wing tank14, a right wing tank16, and/or a center tank18), one or more surge tanks20,22(e.g., a left wing surge tank20and/or a right wing surge tank22), one or more fluid valves24,26,28(e.g., a first fluid valve24, a second fluid valve26, and/or a third fluid valve28), and/or an electronic control unit (ECU)30. The aircraft fuel tank inerting system10may be configured to maintain certain maximum levels of oxygen (O2) in the air in the fuel tanks14,16,18, such as to reduce or eliminate the risk of a fire or explosion.

With embodiments, such as generally illustrated inFIGS.1and2, the inert air assembly12may be configured to receive fluid, such as bleed air32from the aircraft engines102and provide inert air34. The inert air34may, for example and without limitation, include nitrogen enriched air (NEA). The bleed air32from the engines102may flow to a bleed air isolation valve36of the inert air assembly12. The bleed air32may then flow to a pressure switch38(e.g., a differential pressure switch) and a filter/ozone converter40that may be connected in parallel. A pressure sensor42and/or a temperature sensor44may be connected between (i) the isolation valve36and (ii) the pressure switch38and the filter/ozone converter40. Water may be removed from the bleed air32and drained. The bleed air32may flow to one or more air separation modules (ASM)46. The ASM(s)46may be configured to reduce the amount of oxygen in the bleed air32and/or increase the amount of nitrogen (or other inert gas) in the bleed air32, such as to provide inert air34. The ASM(s)46may be configured to provide inert air34that may include less than 20% oxygen, less than 15% oxygen, less than 10% oxygen, and/or less than 5% oxygen, or other levels of oxygen. Oxygen enriched air (OEA) may be a byproduct of the ASMs46and may be vented, such as via a ram air exit48. The inert air34may be provided to the tanks14,16,18, such as via a flow control valve50, a high flow orifice52, and/or a low flow orifice54. A pressure sensor42and/or an oxygen sensor56may be connected at or about an outlet of the ASM(s)46. A pressure sensor42and/or a drain/pressure relief valve58may be connected between the orifice(s)52,54and a flame arrestor/check valve60that may be disposed at the inert air outlet62of the inert air assembly12.

In embodiments, an ECU30may be configured to control one or more portions of the inert air assembly12, such as, for example and without limitation, the bleed air isolation valve36, the differential pressure switch38, the filter/ozone converter40, the ASM(s)46, and/or the flow control valve50. The inert air assembly12may, for example and without limitation, be disposed at least partially in a wing104,106of an aircraft100, such as in a fairing of a wing104,106.

With embodiments, such as generally illustrated inFIG.3, an aircraft100may include one or more main fuel tanks14,16,18, such as a left wing tank14, a right wing tank16, and/or a center tank18. Additionally or alternatively, an aircraft100may include one or more surge tanks20,22, such as a left surge tank20and a right surge tank22. The surge tanks20,22may be configured to receive fuel from the main fuel tanks14,16,18, such as if high temperatures cause fuel in the main tanks14,16,18to expand, fuel slosh due to maneuvering, and/or refuel overflow. The aircraft fuel inerting system12may be configured to provide inert air34to some or all of the tanks14,16,18.

In embodiments, such as generally illustrated inFIGS.3,4A, and4B, the surge tanks20,22may include one or more surge tank components64,66. For example and without limitation, the surge tanks20,22may include one or more climb and dive valve68, depressurization valve70(e.g., for refueling and emergency descent), a flame arrestor72, and/or one or more drains/pressure relief valves74. The surge tank components64,66may be in fluid communication with the environment (e.g., ambient/outside air) and may be configured to vent air from the tanks14,16,18if the pressure in the tanks14,16,18is above a threshold and/or may be configured to receive external air if the pressure in the tanks14,16,18(or a pressure differential) is below a threshold. The surge tanks20,22may be disposed at or about outer ends of the wings104,106of an aircraft100.

With embodiments, such as generally illustrated inFIGS.1,3, and5A-5C, the aircraft fuel tank inerting system10may include one or more fluid valves24,26,28. For example and without limitation, an aircraft fuel tank inerting system12may include a fluid valve24,26for each surge tank20,22, but a fluid valve28could be utilized with more than one surge tank20,22. A fluid valve24,26,28may be configured to control the flow of inert air34(from the inert air assembly12) into the tanks14,16,18. An inlet76of the fluid valve24,26,28may be in fluid communication with an outlet62of the inert air assembly12. A first outlet78of the fluid valve24,26,28may be in fluid communication with a main/wing tank14,16,18. A second outlet80of the fluid valve24,26,28may be fluid communication with a surge tank20,22. In a first/closed position, as generally illustrated inFIG.5A, the fluid valve24,26,28may block fluid communication between the inlet76, and the first and second outlets78,80(e.g., may not provide inert air34to any of the tanks14,16,18,29,22), such as to enable the execution of BIT (built-in-test) to check for latent failures of the fluid distribution system. In a second/open position, as generally illustrated inFIG.5B, the fluid valve24,26,28may provide fluid communication between the inlet76and the first outlet28(e.g., provide inert air34to a main/wing tank14,16,18). In a third/bypass position, as generally illustrated inFIG.5C, the fluid valve24,26,28may provide fluid communication between the inlet76and the second outlet80(e.g., provide inert air34to a surge tank20,22). The fluid valve24,26,28may be disposed in a main tank14,16,18, partially in a surge tank20,22, or entirely in a surge tank20,22.

In embodiments, the ECU30may be configured to control operation of the fluid valve(s)24,26,28, such as between the closed, open, and bypass positions. The ECU30may operate a fluid valve24,26,28(e.g., the first fluid valve24, the second fluid valve26, and/or the third fluid valve28) in a closed position if air in the fuel tanks14,16,18has a sufficiently low oxygen concentration and/or if the aircraft100is on the ground. The ECU30may be connected to a sensor82(e.g., a weight on wheels sensor) that may indicate whether the aircraft100to which the ECU30is connected is on the ground. If the ECU30determines that the aircraft100is on the ground, the ECU30may operate (or maintain) the fluid valve24,26,28in the closed position. Additionally or alternatively, the ECU30may operate the fluid valve in the closed position during a cruise phase of a flight if the tanks14,16,18reach a sufficient inert margin (e.g., oxygen concentration at about 14% or below). The ECU30may operate the fluid valve in the closed position for testing, such as built-in-test (BIT) functions, that may evaluate operation of one or more other valves14,16,18in the fuel tank inerting system10. The ECU30may be configured to independently control the first fluid valve24, the second fluid valve26, and the third fluid valve28. The ECU30may be connected to one or more sensors84that may be configured to obtain information about the tanks14,16,18, such as, for example and without limitation, oxygen sensors that may provide information about the concentration of oxygen in the air in the tanks14,16,18.

With embodiments, the ECU30may operate the fluid valve24,26,28in an open/second position during a climb phase of a flight and/or during a cruise phase of the flight (e.g., if the tanks have not reached a sufficient inert margin). In the open position, the fluid valve may provide inert air34from the inert air assembly12to a tank14,16,18via one or more first fluid conduits86. The inert air34may flow into the first fluid conduits86and may exit the first fluid conduits86into the tanks14,16,18at one or more locations along the first fluid conduits86. The inert air34may mix with the tank air, which may have a higher oxygen concentration than the inert air34, to reduce the oxygen concentration of the tank air, such as to a level below a threshold (e.g., 12% under 20,000 feet, and 14% between 20,000 feet and a cruise ceiling of about 43,000 feet).

In embodiments, the ECU30may be configured to operate a fluid valve24,26,28in a bypass/third position. In the bypass position, the fluid valve24,26,28may provide inert air34from the inert air assembly12to a surge tank20,22. The ECU30may operate the fluid valve24,26,28in the bypass position during a descent phase of a flight and/or if the pressure in the tanks14,16,18is significantly lower than an ambient air pressure. In such circumstances, outside/ambient air may flow into the surge tank20,22and then into the main tanks14,16,18to equalize the pressure in the main tanks, at least to some degree. The ambient air entering the surge tank20,22may include a relatively high concentration of oxygen, such as about 20-22%. The fluid valve24,26,28may provide the inert air34to the surge tank20,22, and the inert air34may mix with the ambient air in the surge tank20,22(e.g., the surge tank20,22may act as a mixing chamber). The resulting mixed air may include a reduced oxygen concentration. For example and without limitation, the mixed air may include an oxygen concentration of about 14-16%. The mixed air may flow from the surge tank20,22into second fluid conduits88that may be connected to one or more main tanks14,16,18. The mixed air may flow through the second fluid conduits88and may exit the second fluid conduits88into the main tank(s)14,16,18at one or more locations along the second fluid conduits88. The mixed air may continue to mix in the second fluid conduits88.

In embodiments, a first fluid valve24may be connected to the left wing tank14and the left surge tank20, a second fluid valve26may be connected to the right wing tank16and the right surge tank22, and/or a third fluid valve28may be connected to the center tank18and one or both of the surge tanks20,22. The first fluid valve24and the second fluid valve26may include substantially the same configuration (e.g., with closed, open, and bypass positions). The third fluid valve28may include a different configuration than the first and second fluid valves24,26. For example and without limitation, the third fluid valve28may include a closed position and an open position and may not include a bypass position. The ECU30may operate the third fluid valve28in the open position to reduce the oxygen concentration in the center tank18.

With embodiments, the second fluid conduits88may be connected to the left surge tank20and the right surge tank22. The second fluid conduit(s)88connected to the first surge tank20may provide fluid communication from the first surge tank20to the left wing tank14and/or to the center tank18. The second fluid conduit(s)88connected to the second surge tank22may provide fluid communication from the second surge tank22to the right wing tank16and/or to the center tank18. For example and without limitation, the ECU30may operate the first fluid valve24and the second fluid valve26in bypass positions such that mixed air is provided from the left surge tank20and the right surge tank22to the main tanks14,16,18via the second fluid conduits88.

With embodiments, a method of inerting aircraft fuel tanks may include providing an aircraft100having an aircraft fuel tank inerting system10, at least one fuel tank14,16,18, and/or at least one surge tank20,22. The aircraft fuel tank inerting system10may include at least one fluid valve24,26,28and an inert air assembly12. The method may include operating the fluid valve(s)24,26,28in an open position during a climb phase of a flight to provide inert air34from the inert air assembly12to the fuel tank(s)14,16,18. The method may include operating the fluid valve(s)24,26,28in a closed position during a cruise phase of the flight if the fuel tank(s)14,16,18has achieved an inert margin above a threshold. The method may include operating the fluid valve(s)24,26,28in a bypass position during a descent phase of the flight to provide inert air34to the surge tank20,22. The method may include mixing inert air34from the inert air assembly12with ambient air in the surge tank20,22to form mixed air. The mixed air may continue to mix in a second fluid conduit88that may be connected to the surge tank20,22and the fuel tank14,16,18. The method may include providing the mixed air to the fuel tank14,16,18. The method may include operating the (first) fluid valve24and a second fluid valve26in bypass positions to provide mixed air from the (first) surge tank20to the (left wing) fuel tank14, from a second surge tank22to a second (right wing) fuel tank16, and/or from both the (first) surge tank20and the second surge tank22, via second fluid conduits88, to a third (center) fuel tank18. The method may include operating the fluid valve(s)24,26,28in the closed position if the aircraft100is on the ground. One or more portions of the method may be implemented/carried out via the ECU30.

With some designs, outside/ambient air may be provided directly to the main tanks from the surge tank, and inert air may be separately provided to the main tanks. The ambient air may be provided to the main tanks at one or more discrete locations. As the ambient air may include high levels of oxygen, the flow of ambient air into the tanks may result in areas/pockets of higher concentrations of oxygen in the main tank, which may be referred to as “hot spots”. To limit the effect of this arrangement, the air in the main tank may be maintained at an even lower level of oxygen to compensate for ambient air, which may involve providing additional inert air to the main tank. Providing additional inert air to the main tank may involve increasing the capacity and/or duty cycle of an inert air assembly (e.g., increasing the number of ASMs).

In contrast, with embodiments of the aircraft fuel tank inerting system10, ambient air may not be provided directly to the main tanks14,16,18. Instead, the ambient air may be pre-mixed with inert air34such that the air entering the main tanks14,16,18(e.g., mixed air) has a reduced oxygen concentration, which may limit and/or prevent the generation of hot spots. With such embodiments, the maximum capacity of the inert air assembly may be reduced, which may reduce the weight of the inert air assembly (e.g., the inert air assembly may include fewer ASMs which may weigh about 30 lbs. each). Additionally or alternatively, the duty cycle of the inert air assembly12may be reduced as a result of a lower demand for inert air, which may increase the life cycle of the inert air assembly12.

In embodiments, an ECU30may include an electronic controller and/or include an electronic processor, such as a programmable microprocessor and/or microcontroller. In embodiments, an ECU30may include, for example, an application specific integrated circuit (ASIC). An ECU30may include a central processing unit (CPU), a memory (e.g., a non-transitory computer-readable storage medium), and/or an input/output (I/O) interface. An ECU30may be configured to perform various functions, including those described in greater detail herein, with appropriate programming instructions and/or code embodied in software, hardware, and/or other medium. In embodiments, an ECU30may include a plurality of controllers. In embodiments, an ECU may be connected to a display, such as a touchscreen display.

Various embodiments are described herein for various apparatuses, systems, and/or methods. Numerous specific details are set forth to provide a thorough understanding of the overall structure, function, manufacture, and use of the embodiments as described in the specification and illustrated in the accompanying drawings. It will be understood by those skilled in the art, however, that the embodiments may be practiced without such specific details. In other instances, well-known operations, components, and elements have not been described in detail so as not to obscure the embodiments described in the specification. Those of ordinary skill in the art will understand that the embodiments described and illustrated herein are non-limiting examples, and thus it can be appreciated that the specific structural and functional details disclosed herein may be representative and do not necessarily limit the scope of the embodiments.

Reference throughout the specification to “various embodiments,” “with embodiments,” “in embodiments,” or “an embodiment,” or the like, means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment. Thus, appearances of the phrases “in various embodiments,” “with embodiments,” “in embodiments,” or “an embodiment,” or the like, in places throughout the specification are not necessarily all referring to the same embodiment. Furthermore, the particular features, structures, or characteristics may be combined in any suitable manner in one or more embodiments. Thus, the particular features, structures, or characteristics illustrated or described in connection with one embodiment/example may be combined, in whole or in part, with the features, structures, functions, and/or characteristics of one or more other embodiments/examples without limitation given that such combination is not illogical or non-functional. Moreover, many modifications may be made to adapt a particular situation or material to the teachings of the present disclosure without departing from the scope thereof.

It should be understood that references to a single element are not necessarily so limited and may include one or more of such element. Any directional references (e.g., plus, minus, upper, lower, upward, downward, left, right, leftward, rightward, top, bottom, above, below, vertical, horizontal, clockwise, and counterclockwise) are only used for identification purposes to aid the reader's understanding of the present disclosure, and do not create limitations, particularly as to the position, orientation, or use of embodiments.

Joinder references (e.g., attached, coupled, connected, and the like) are to be construed broadly and may include intermediate members between a connection of elements and relative movement between elements. As such, joinder references do not necessarily imply that two elements are directly connected/coupled and in fixed relation to each other. The use of “e.g.” in the specification is to be construed broadly and is used to provide non-limiting examples of embodiments of the disclosure, and the disclosure is not limited to such examples. Uses of “and” and “or” are to be construed broadly (e.g., to be treated as “and/or”). For example and without limitation, uses of “and” do not necessarily require all elements or features listed, and uses of “or” are intended to be inclusive unless such a construction would be illogical.

While processes, systems, and methods may be described herein in connection with one or more steps in a particular sequence, it should be understood that such methods may be practiced with the steps in a different order, with certain steps performed simultaneously, with additional steps, and/or with certain described steps omitted.

It is intended that all matter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative only and not limiting. Changes in detail or structure may be made without departing from the present disclosure.

It should be understood that an electronic control unit (ECU), a system, and/or a processor as described herein may include a conventional processing apparatus known in the art, which may be capable of executing preprogrammed instructions stored in an associated memory, all performing in accordance with the functionality described herein. To the extent that the methods described herein are embodied in software, the resulting software can be stored in an associated memory and can also constitute means for performing such methods. Such a system or processor may further be of the type having ROM, RAM, RAM and ROM, and/or a combination of non-volatile and volatile memory so that any software may be stored and yet allow storage and processing of dynamically produced data and/or signals.

It should be further understood that an article of manufacture in accordance with this disclosure may include a non-transitory computer-readable storage medium having a computer program encoded thereon for implementing logic and other functionality described herein. The computer program may include code to perform one or more of the methods disclosed herein. Such embodiments may be configured to execute via one or more processors, such as multiple processors that are integrated into a single system or are distributed over and connected together through a communications network, and the communications network may be wired and/or wireless. Code for implementing one or more of the features described in connection with one or more embodiments may, when executed by a processor, cause a plurality of transistors to change from a first state to a second state. A specific pattern of change (e.g., which transistors change state and which transistors do not), may be dictated, at least partially, by the logic and/or code.