Lubrication system for an aircraft

Abstract

A lubrication system for an aircraft, the lubrication system comprising: a lubricating oil (LO) tank configured to operate at a first internal pressure; an intake chamber (IC) configured to operate at a second internal pressure greater than the first internal pressure, the IC comprising an inlet port configured to receive LO from a sump of a device of the aircraft; an overflow port in fluid communication with the LO tank; and a supply port in fluid communication with the sump and configured to supply LO to the sump.

Description

Technical Field

[0001] This topic generally relates to lubrication systems for aircraft, and more specifically to lubrication systems for aircraft operating in various attitudes relative to gravity. Background Technology

[0002] Under certain maneuvers, aircraft experience significant load conditions, which can lead to insufficient oil supply to one or more parts of the engine. That is, due to excessive directional forces associated with certain aerial maneuvers, the lubricating oil used in the aircraft's equipment may be affected by pressure loss and aeration. For example, when the aircraft pulls under high G loads, such as when performing rapid turns and attitude adjustments, lubricating oil may accumulate in one or more areas of the lubrication system, preventing adequate distribution to the aircraft's equipment. Similarly, when flying at a specific attitude relative to gravity, the lubrication system may also fail to deliver lubricating oil to the equipment due to inlet / outlet locations that are not actively immersed in lubricating oil.

[0003] As a result, aircraft equipment will be damaged, components will wear out prematurely, and the lifespan of equipment will be shortened. Therefore, the aircraft industry needs to improve the lubrication system of aircraft. Summary of the Invention

[0004] Aspects and advantages of the invention will be set forth in part in the description which follows, or may be apparent from the description or may be learned by practice of the invention.

[0005] In one exemplary embodiment of this disclosure, a lubrication system for an aircraft includes: an oil (LO) tank configured to operate under a first internal pressure; and an inlet chamber (IC) configured to operate under a second internal pressure greater than the first internal pressure, the IC including: an inlet port configured to receive LO from a reservoir of equipment of the aircraft; an overflow port in fluid communication with the LO tank; and a supply port in fluid communication with the reservoir and configured to supply LO to the reservoir.

[0006] According to another exemplary embodiment, an aircraft includes: a device including a reservoir configured to receive lubricating oil (LO); and a lubrication system in fluid communication with the reservoir and configured to continuously supply LO to the reservoir at a substantially constant pressure independent of the aircraft's attitude relative to gravity.

[0007] According to another exemplary embodiment, a method of installing a lubrication system in an aircraft includes: providing an oil inlet chamber (IC) in the aircraft such that an inlet port of the IC is in fluid communication with a reservoir of lubricating oil (LO) exiting the aircraft; fluidly connecting an overflow port of the IC to a LO tank of the aircraft; and fluidly connecting a supply port of the IC to the reservoir, the IC being configured to supply LO to the reservoir.

[0008] These and other features, aspects, and advantages of the invention will be better understood by reference to the following description and the appended claims. The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention. Attached Figure Description

[0009] The complete and effective disclosure of the invention, including its best mode, is set forth in the description with reference to the accompanying drawings and is intended for use by those skilled in the art.

[0010] Figure 1 This is a perspective view of an aircraft according to exemplary embodiments of the present disclosure.

[0011] Figure 2 This is a cross-sectional view of an exemplary engine according to an exemplary embodiment of the present disclosure.

[0012] Figure 3 This is a cross-sectional view of a lubricating oil system according to an exemplary embodiment of the present disclosure.

[0013] Figure 4 This is a schematic diagram of a lubricating oil system according to an exemplary embodiment of the present disclosure.

[0014] Figure 5 An exemplary method for installing a lubrication system in an aircraft is shown according to an exemplary aspect of this disclosure.

[0015] The repeated use of reference numerals in this specification and drawings is intended to indicate the same or similar features or elements of the invention. Detailed Implementation

[0016] Reference will now be made in detail to the present embodiments of the invention, one or more examples of which are illustrated in the accompanying drawings. The detailed description uses numbers and letters to refer to features in the drawings. The same or similar reference numerals in the drawings and description have been used to refer to the same or similar parts of the invention.

[0017] The term "exemplary" is used herein to mean "serving as an example, instance, or illustration." Any implementation described herein as "exemplary" is not necessarily to be construed as superior or better than other implementations. Furthermore, each example is provided to explain the invention, not to limit it. In fact, it will be apparent to those skilled in the art that various modifications and variations can be made to the invention without departing from its scope. For example, features shown or described as part of one embodiment may be used with another embodiment to produce yet another embodiment. Therefore, the invention is intended to cover these modifications and variations that fall within the scope of the appended claims and their equivalents.

[0018] As used herein, the terms “first,” “second,” and “third” are used interchangeably to distinguish one component from another and are not intended to indicate the location or importance of the components. The singular forms “a,” “an,” and “the” include plural references unless the context clearly specifies otherwise. Unless otherwise stated, the terms “connection,” “fixed,” “attached to,” etc., refer both to a direct connection, fixation, or attachment, and to an indirect connection, fixation, or attachment via one or more intermediate components or features.

[0019] The terms "front" and "rear" refer to relative positions within a gas turbine engine or carrier, and specifically to the normal operating posture of the gas turbine engine or carrier. For example, for a gas turbine engine, "front" refers to the position closer to the engine propeller or exhaust system, while "rear" refers to the position closer to the engine inlet. The terms "upstream" and "downstream" refer to the relative directions of fluid flow within a fluid path. For example, "upstream" refers to the direction from which fluid flows, and "downstream" refers to the direction from which fluid flows.

[0020] The approximate language used throughout the specification and claims is applied to modify any quantitative expression that may allow for change without altering its associated essential function. Therefore, values ​​modified by one or more terms such as “about,” “approximately,” and “substantially” are not limited to specified precise values. In at least some cases, approximate language may correspond to the precision of the instrument used to measure the value, or the precision of the method or machine used to construct or manufacture the component and / or system. For example, approximate language may refer to margins of 1%, 2%, 4%, 10%, 15%, or 20%. These approximate margins may apply to a single value, to either or both endpoints of a defined numerical range, and / or to the margin of the range between endpoints.

[0021] Throughout this specification and claims, scope limitations are combined and interchanged, and unless the context or language otherwise indicates otherwise, such scopes are identified and include all subscopes contained herein. For example, all scopes disclosed herein include endpoints, and endpoints may be combined independently of each other.

[0022] Generally, the embodiments of this disclosure described herein relate to lubrication systems for aircraft. The lubrication system is configured to supply lubricating oil (LO) to one or more reservoirs of the aircraft's equipment at a substantially constant pressure independent of the aircraft's attitude relative to gravity. Therefore, the lubrication systems described herein may be particularly useful for aircraft configured to operate over a wide range of attitudes. Exemplary aircraft include aerobatic aircraft operating at high G-loads and in all directional attitudes.

[0023] Refer to the attached diagram. Figure 1 An exemplary aircraft 100 according to one or more embodiments described herein is illustrated. Figure 1 The aircraft 100 depicted is a stunt plane constructed to operate within a wide range of attitudes and G-loads. Aircraft 100 includes an engine, such as a turboprop engine 200. Figure 2 The propeller 102, which is configured to generate thrust, is powered. In an embodiment, the aircraft 100 has a rated power of at least 500 horsepower (HP), for example at least 550 HP, for example at least 600 HP, for example at least 650 HP, for example at least 700 HP, for example at least 750 HP, for example at least 800 HP, for example at least 850 HP.

[0024] refer to Figure 2 The turboprop engine 200 typically includes an air inlet 202 configured to supply air to a combustion chamber 204. An exhaust system 206 is configured to discharge gases from the turboprop engine 200. More specifically, the turboprop engine 200 includes a compressor 212 configured to receive and compress air from the air inlet 202. The compressed air from the compressor 212 is supplied to the combustion chamber 204, where it is burned with fuel to produce combustion gases. The combustion gases are supplied to a first turbine 218, where they expand to rotate the first turbine 218, which in turn drives the compressor 212 via a first shaft 220. The combustion gases then flow to a second turbine 222, where they further expand to rotate the second turbine 222, which in turn drives a second shaft 224. The second shaft 224 drives a propeller shaft 214 across a reduction gearbox 210, and the propeller shaft 214 drives a propeller 216.

[0025] The turboprop engine 200 also includes an accessory gearbox 208. The accessory gearbox 208 is driven by a first shaft 220. The accessory gearbox 208 can provide power to the engine 200 and / or one or more accessory systems of the aircraft 100 incorporating the engine 200.

[0026] Although not depicted, engine 200 and aircraft 100 may also include controllers for controlling the operation of engine 200, such as an electronic engine control system (EECS) connected to a control stick.

[0027] It should be understood that Figure 2 The turboprop engine 200 depicted herein is merely an example of an engine from which the lubrication system described herein can be utilized. According to other embodiments, the engine may include additional or other features and / or components, or be a completely different engine type, such as a turbine shaft, turbofan, turbojet, etc.

[0028] Although not explicitly described, and as described in more detail below, engine 200 is equipped with an oil lubrication (LO) system that avoids the oil shortage that can occur in conventional engines, such as during certain aircraft maneuvers. More specifically, the LO system can prevent oil shortages that may occur in conventional engines during instantaneous high absolute G loads (e.g., at -4Gs or 7Gs) and / or in attitudes exceeding 10° relative to gravity (e.g., attitudes exceeding 15° relative to gravity, attitudes exceeding 20° relative to gravity, attitudes exceeding 25° relative to gravity, attitudes exceeding 30° relative to gravity, attitudes exceeding 35° relative to gravity, attitudes exceeding 40° relative to gravity, attitudes exceeding 45° relative to gravity, attitudes exceeding 50° relative to gravity, attitudes exceeding 55° relative to gravity, attitudes exceeding 60° relative to gravity, attitudes exceeding 65° relative to gravity, attitudes exceeding 70° relative to gravity, attitudes exceeding 75° relative to gravity, attitudes exceeding 80° relative to gravity, attitudes exceeding 85° relative to gravity, attitudes exceeding 90° relative to gravity). When attitudes exceed the aforementioned angles, or during periods of high absolute G-load, conventional engines may experience fuel shortages due to displacement of the LO relative to the system. For example, when flying in a high attitude relative to gravity (e.g., inverted), the LO may shift from the lower side of the engine or associated components to its higher side. This results in a momentary loss of LO pressure, which can affect engine performance or even damage the engine and / or one or more of its components. The embodiments of the LO system described herein are designed to prevent fuel shortages and / or loss of functional control (e.g., propeller control or hydraulic torque measurement) under all anticipated aircraft maneuvers.

[0029] As described in more detail below, engine 200 may include a dry reservoir with a multi-position LO chamber. In embodiments, the multi-position LO chamber may be integrated into accessory gearbox 208. The multi-position LO chamber may be referred to as an inlet chamber (IC). The IC can provide pressurized and filtered LO for lubricating and cooling components of engine 200, such as bearings and gears. In some cases, the pressurized LO can also be used as hydraulic fluid for torque measurement and / or propeller speed control in reduction gearbox 210. In other cases, the pressurized LO can be used for fault detection because debris (e.g., worn particles) can be transmitted to a signaling system (not shown) via the pressurized LO.

[0030] Figure 3 A cross-sectional view of a lubrication system 300 according to an embodiment is shown. The lubrication system 300 provides pressurized and, optionally filtered, LO (lubricant flow rate) to nozzles (not shown) for lubrication of, for example, bearings and gears, and for lubrication at, for example, at the inlet gear pump of a propeller regulating system and torque measurement system. It should be understood that the lubrication system 300 can also perform additional functions within the aircraft 100. Furthermore, the lubrication system 300 can be integrated with… Figure 2 It can be incorporated into the accessory gearbox 208 of the engine 200, or it can be integrated into the engine (e.g., any other suitable turboprop engine, turbofan engine, turboshaft engine, etc.) in any other suitable manner.

[0031] like Figure 3 The lubrication system 300 described herein may include a main supply pump 302 configured to bias the LO to one or more lubrication points of the engine 200, such as the aforementioned bearings and gears, via an outlet line 301. In an exemplary embodiment, the main supply pump 302 may include a gear pump comprising a plurality of gears configured to mesh and pump the LO by displacement. The gear pump may include an external gear pump or an internal gear pump. In an embodiment, the main supply pump 302 may be a single-stage gear pump. The main supply pump 302 may include a stationary surface having a gear shaft lubricated by the LO. In other non-limiting embodiments, the main supply pump 302 may include a vane pump. The LO biased by the main supply pump 302 may pass through one or more filters and / or pressure regulating valves before contacting the lubrication points of the engine 200.

[0032] In this embodiment, the inlet of the main supply pump 302 is fluidly connected to IC 304 via an outlet line 301. In this way, the main supply pump 302 can bias the LO from IC 304 to the lubrication point. A rotary inlet pickup 306 may be disposed within IC 304 and fluidly connected to the main supply pump 302 to IC 304. The rotary inlet pickup 306 can rotate about a pivot point 305 in a direction 307 relative to IC 304. For example, the rotary inlet pickup 306 may be configured to rotate at least 5° relative to IC 304 about pivot point 305, such as at least 10°, at least 15°, at least 20°, at least 30°, at least 40°, at least 50°, at least 60°, at least 70°, at least 80°, or at least 90°. Rotation of the rotary inlet pickup 306 may be caused by gravity, one or more motors, or a combination thereof. The rotary inlet pickup 306 may include a filtration device or other filter (not shown) configured to remove debris from LO to protect the engine 200.

[0033] In an embodiment, IC 304 may be at least partially disposed within the LO tank 308 of the lubrication system 300. More specifically, IC 304 may be completely disposed within the LO tank 308. The LO tank 308 may define a main storage for LO within the aircraft 100. In an embodiment, the LO tank 308 may serve as an overflow relief device for LO via IC 304. For example, in one or more embodiments, IC 304 may include an overflow port 310 in fluid communication with the LO tank 308. Since LO is biased into IC 304 (as described in more detail below), overflowing LO, i.e., excess LO, may enter the LO tank 308 through the overflow port 310. In some cases, the overflow port 310 may define a static geometry and / or size. In other cases, the overflow port 310 may define a variable geometry and / or size. Alternatively, the overflow port 310 may be interchangeable among a variety of different shapes and / or sizes. Using interchangeable or variable overflow ports 310 allows for selective pressurization of IC 304, which in turn affects the efficiency of LO delivery and back pressure within the lubrication system 300.

[0034] In some cases, the overflow port 310 can be configured to substantially continuously deliver LO flow from IC 304 to LO tank 308 during operation of the aircraft 100. In an embodiment, the overflow port 310 can continuously deliver LO to LO tank 308 during operation. In this way, the lubrication system 300 can maintain the desired pressure without oil shortage.

[0035] IC 304 defines a first internal volume for receiving LO (Local Request), while LO box 308 defines a second internal volume for receiving LO. In an embodiment, the first volume of IC 304 may be smaller than the second volume of LO box 308. For example, the first volume may be less than 95% of the second volume, such as less than 90% of the second volume, such as less than 75% of the second volume, such as less than 50% of the second volume, such as less than 25% of the second volume.

[0036] The LO located within the LO tank 308 but not within the IC 304 can be part of a supplemental fluid loop to be recirculated back to the IC 304. According to an embodiment, the main supply pump 302 is not in direct fluid communication with the LO located within the LO tank 308 but outside the IC 304. However, the main supply pump 302 may be in direct fluid communication with the LO located within the IC 304.

[0037] In an embodiment, the lubrication system 300 may further include an LO return system, which includes a plurality of return pumps 312 configured to bias the LO within the lubrication system 300. In some cases, all return pumps 312 may include similar or identical configurations. In other cases, at least two return pumps 312 may be different from each other. The return pumps 312 may include similar or different configurations compared to the main supply pump 302. In a particular embodiment, at least one of the return pumps 312 includes a gear pump comprising a plurality of gears configured to mesh and pump the LO by displacement. The gear pump may include an external gear pump or an internal gear pump.

[0038] The return oil system, such as the return oil pump 312, can be configured to bias the LO back to IC 304 (as described in more detail below) after the equipment circulates through the aircraft 100.

[0039] Figure 4A schematic diagram of a lubrication system 300 according to an exemplary embodiment is shown. As described above, the lubrication system 300 can be used to provide LO to a device 314 of an aircraft 100. The device 314 may include, for example, bearings, gears, and / or other components of the engine 200 and / or non-engine-related components of the aircraft 100. For example, the device 314 may have one or more dispensers of the lubrication system 300, such as nozzles (not shown), positioned relative to the device 314 to dispense LO to one or more desired locations along the device 314. In the illustrated embodiment, the lubricated device 314 includes a bearing assembly 316 configured to allow low-friction rotation of a shaft 318. In some exemplary embodiments, the shaft 318 may be as described above regarding... Figure 2 The first shaft 220, the second shaft 224, or the propeller shaft 214 described herein. However, alternatively, the shaft 318 may be any other suitable shaft, and / or the bearing assembly 316 may support any other suitable rotating component.

[0040] Still referencing Figure 4 At least a portion of the bearing assembly 316 and the shaft 318 may be disposed within the reservoir 320. The reservoir 320 may include an internal volume within which at least a portion of the bearing assembly 316 and the shaft 318 is disposed. The reservoir 320 may define one or more areas where LO can be collected. These areas may include portions of the reservoir 320 where one or more outlet ports may be provided, such as a first outlet port 322 and a second outlet port 324. The first outlet port 322 and the second outlet port 324 may be in fluid communication with the internal volume of the reservoir 320, thereby allowing LO to flow out of the reservoir 320. As shown, the first outlet port 322 and the second outlet port 324 may generally be spaced apart from each other. For example, the first outlet port 322 may be located on a first side of the reservoir 320, such as the lower side of the reservoir 320, and the second outlet port 324 may be located on a second side of the reservoir 320, such as the upper side of the reservoir 320. In a more specific embodiment, the first outlet port 322 and the second outlet port 324 may be located at positions configured to collect LO in various attitudes of the aircraft 100. The first outlet port 322 and the second outlet port 324 may allow LO to flow out of the reservoir 320 regardless of the attitude of the aircraft 100, such as as measured relative to gravity.

[0041] The first outlet port 322 may be in fluid communication with the first fluid channel 326. Similarly, the second outlet port 324 may be in fluid communication with the second fluid channel 328. The first fluid channel 326 and the second fluid channel 328 may extend parallel to the reservoir 320 and join together downstream therefrom. When the aircraft 100 operates in a first attitude, the LO in the reservoir 320 may exit through the first outlet port 322 and through the first fluid channel 326. When the aircraft 100 is maneuvered to a second attitude, the LO in the reservoir 320 may exit through the second outlet port 322 and through the second fluid channel 328. In some cases, the maneuvering of the aircraft 100 may cause the LO outlet to move completely from one of the first outlet port 322 and the second outlet port 324 to the other. However, in many cases, the outflow of LO from the reservoir 320 may include the simultaneous use of the first outlet port 322 and the second outlet port 324 at different rates. That is, both the first outlet port 322 and the second outlet port 324 may facilitate the outflow of LO from the reservoir 320 at different relative ratios based on the maneuvering of the aircraft 100.

[0042] A first return pump 330 of the return oil system is disposed along a first fluid passage 326. The first return pump 330 may be part of the aforementioned plurality of return pumps 312. The first return pump 330 may bias the LO through the first fluid passage 326. Similarly, a second return pump 332 of the return oil system is disposed along a second fluid passage 328. The second fluid passage 328 may be part of the aforementioned plurality of return pumps 312. The second return pump 332 may bias the LO through the second fluid passage 328. In an alternative embodiment, the LO within the first fluid passage 326 and the second fluid passage 328 may be biased by different return pump arrangements. For example, the first fluid passage 326 and the second fluid passage 328 may be joined together upstream of a common return pump. In an embodiment, the first return pump 330 and the second return pump 332 may be configured to generate biasing forces in the first fluid passage 326 and the second fluid passage 328 only when conditions occur (e.g., when an LO is detected in the passage, when certain threshold acceleration forces are present, when a change in attitude is detected, etc.).

[0043] In some cases, reservoir 320 may not have an outlet for venting air from it. Therefore, air entering reservoir 320, for example, through a labyrinth seal, can be removed from reservoir 320 along with the LO. The LO leaving reservoir 320 and entering the first fluid passage 326 and / or the second fluid passage 328 may include air from reservoir 320 in the form of bubbles, cavitation, etc. Air from reservoir 320 can travel through the first fluid passage 326 and / or the second fluid passage 328 and be biased by the first return pump 330 and / or the second return pump 332.

[0044] An oil-gas separator 334, sometimes referred to as a degasser, can be installed in the fluid circuit of the lubrication system 300 to separate air leaving the reservoir 320 from the LO. In an embodiment, the oil-gas separator can be located downstream of the first return oil pump 330 and the second return oil pump 332, or refer to... Figure 3 Downstream of multiple return oil pumps 312. In the illustrated embodiment, the oil-gas separator 334 may include a rotary degassing system configured to separate oil and air upon the presence of centripetal force. When rotating, for example, along direction 336, air and LO can separate from each other and move through the lubrication system 300 via different routes. LO can exit the oil-gas separator 334 through LO passage 338, while air can exit the oil-gas separator 334 through a separate air passage 340.

[0045] The LO channel 338 can be in fluid communication with the aforementioned IC 304. More specifically, the LO channel 338 can be directly in fluid communication with IC 304 through the inlet port 342 of IC 304. At the same time, the air contained in the air channel 340 can be discharged to the external environment through the outlet 344.

[0046] The LO (Local Optical Array) within IC 304 can be relatively pressurized. For example, the internal pressure within IC 304 can be greater than approximately 1 atmosphere, such as greater than approximately 1.25 atmospheres, greater than approximately 1.5 atmospheres, greater than approximately 1.75 atmospheres, greater than approximately 2 atmospheres, greater than approximately 2.5 atmospheres, greater than approximately 3 atmospheres, greater than approximately 4 atmospheres, greater than approximately 5 atmospheres, greater than approximately 6 atmospheres, greater than approximately 7 atmospheres, greater than approximately 8 atmospheres, greater than approximately 9 atmospheres, or greater than approximately 10 atmospheres. Therefore, the LO within IC 304 can be maintained under pressure.

[0047] In an embodiment, the LO box 308 may be configured to operate under a first internal pressure, while the IC 304 may be configured to operate under a second internal pressure different from the first internal pressure. In a more specific embodiment, the second internal pressure may be greater than the first internal pressure. For example, the second internal pressure may be at least 101% of the first internal pressure, such as at least 105%, at least 110%, at least 115%, at least 120%, at least 125%, at least 130%, at least 135%, at least 140%, at least 145%, or at least 150% of the first internal pressure.

[0048] Pressure maintenance within IC 304 can be achieved, for example, by pressurizing LO to a first pressure P through inlet port 342 of IC 304. l This is achieved by... Simultaneously, the overflow port 310 allows LO to overflow from IC 304 into LO tank 308 at a second pressure P2. The supply port 346, extending to the main supply pump 302, allows LO to exit IC 304 at a third pressure P3. By balancing P1, P2, and P3, it is possible to achieve the desired internal pressure within IC 304. That is, according to the embodiment, P1 can be substantially equal to the sum of P2 and P3 [P1 = P2 + P3]. By increasing P1, P2 and / or P3 must increase by an equal amount to maintain a constant pressure within IC 304. Conversely, by decreasing P1, P2 and / or P3 must decrease by an equal amount to maintain a constant pressure within IC 304. Therefore, the pressure in IC 304 can be increased by increasing P1 while keeping P2 and P3 at a fixed value, or by decreasing one or both of P2 and / or P3 while keeping P1 at a fixed value. Similarly, the pressure in IC 304 can be reduced by decreasing P1 while keeping P2 and P3 at fixed values, or by increasing one or both of P2 and / or P3 while keeping P1 at a fixed value. In some cases, a substantially constant internal pressure within IC 304 can be defined by selecting an appropriate overflow port 310. That is, for example, the internal pressure within IC 304 can be maintained by limiting the LO flow rate to a desired amount through the overflow port 310. In a preferred embodiment, P3 can be kept substantially constant throughout or substantially throughout the operation of the aircraft 100.

[0049] Because IC 304 is generally under continuous pressure, the risk of oil shortage at device 314 is greatly reduced during certain air operations. That is, while conventional lubrication systems may experience momentary oil pressure failure due to oil sloshing in conventional LO tanks, potentially exposing the supply port to air consumption, maintaining pressure on IC 304 prevents such momentary oil pressure failure.

[0050] In some embodiments, the lubrication system 300 may further include an LO bypass port 315. The LO bypass port 315 may be configured to provide fluid communication between the supply port 346 and the reservoir 320. The LO bypass port 315 may include a controller, such as a regulating valve 303, to control the LO supply pressure to the reservoir 320. LO may be selectively allowed through the LO bypass port 315 to accommodate a desired LO supply pressure.

[0051] The LO within the lubrication system 300 can be further circulated through a replenishment fluid circuit. The replenishment fluid circuit may include, for example, one or more replenishment fluid channels, such as a first replenishment fluid channel 348 and a second replenishment fluid channel 350 in fluid communication with the LO tank 308. The first replenishment fluid channel 348 and the second replenishment fluid channel 350 may be fluidly connected to substantially opposite sides of the LO tank 308. For example, the first replenishment fluid channel 348 may be fluidly connected to the lower end of the LO tank 308, while the second replenishment fluid channel 350 may be fluidly connected to the upper end of the LO tank 308. Thus, similar to the first fluid channel 326 and the second fluid channel 328 described above with respect to the reservoir 320, at least one of the first replenishment fluid channel 348 and the second replenishment fluid channel 350 can draw LO from the LO tank 308, regardless of the air maneuver performed.

[0052] The first replenishing fluid channel 348 and the second replenishing fluid channel 350 can also be fluidly connected upstream of IC 304. For example, in an embodiment, the first replenishing fluid channel 348 and the second replenishing fluid channel 350 can be fluidly connected upstream of the oil-gas separator 334. Therefore, the LO from the LO tank 308 can be recirculated back to IC 304 and through the oil-gas separator 334 via the replenishing fluid loop, wherein the air from the LO tank 308 can be discharged to the external environment through the exhaust port 344.

[0053] The first replenishment fluid channel 348 and the second replenishment fluid channel 350 may each include replenishment pumps 352 and 354 to bias the LO from the LO tank 308, respectively. Furthermore, each of the first replenishment fluid channel 348 and the second replenishment fluid channel 350 may include temporary LO storage volumes 356 and 358, respectively, to maintain the LO within the replenishment fluid loop and be ready to allocate it to IC 304 in the event of a need for additional LO. That is, with LO already present in the replenishment fluid loop, potential delays during certain in-flight maneuvers that could lead to fuel shortages can be further reduced.

[0054] Compared to a conventional lubrication system 300, the use of a lubrication system 300 according to one or more embodiments described herein can exhibit a more uniform LO distribution over a wider range of operating conditions. In some cases, the lubrication system 300 described herein can maintain a substantially constant LO supply to the equipment under all safe operating conditions of the aircraft 100. In embodiments, the lubrication system 300 can be configured to supply a substantially constant pressure LO to the equipment's reservoir. For example, the lubrication system 300 can be configured to deviate from the desired pressure of the lubricated equipment by less than 1 pound per square inch (PSI) during aircraft operation, such as less than 0.75 PSI, less than 0.5 PSI, less than 0.25 PSI, less than 0.2 PSI, less than 0.15 PSI, or less than 0.1 PSI. Furthermore, the lubrication system 300 may be configured to distribute LO to the equipment at a fluid ratio [LO:air] as described by the volume ratio of LO to air, not less than 5:1 (e.g., not less than 10:1, not less than 15:1, not less than 20:1, not less than 30:1, not less than 50:1). A higher fluid ratio may indicate improved equipment performance and / or extended equipment life.

[0055] Figure 5 An exemplary method 500 for providing a lubrication system in an aircraft is illustrated. Method 500 may include step 502, providing an oil inlet chamber (IC) in the aircraft such that the inlet port of the IC is in fluid communication with a reservoir of lubricating oil (LO) exiting the aircraft's equipment. In an embodiment, step 502 of providing the IC in the aircraft may be performed such that the IC is at least partially (e.g., entirely) provided within a volume defined by the LO tank. Method 500 may further include step 504, fluidly connecting the overflow port of the IC to the LO tank of the aircraft. Method 500 may further include step 506, fluidly connecting the supply port of the IC to the reservoir. In an embodiment, the lubrication system may be retrofitted to an existing aircraft. That is, a lubrication system may be provided in the later stages of production of an existing aircraft to improve the LO supply to its equipment. In another embodiment, the lubrication system may be provided in the aircraft during the initial production phase of the aircraft.

[0056] Further aspects of the invention are provided by the subject matter of the following clauses:

[0057] Example 1. A lubrication system for an aircraft, the lubrication system comprising: an oil (LO) tank configured to operate under a first internal pressure; and an inlet chamber (IC) configured to operate under a second internal pressure greater than the first internal pressure, the IC comprising: an inlet port configured to receive LO from a reservoir of equipment of the aircraft; an overflow port in fluid communication with the LO tank; and a supply port in fluid communication with the reservoir and configured to supply LO to the reservoir.

[0058] Example 2. A lubrication system according to any one or more of the above embodiments, wherein the IC is configured to maintain a substantially constant pressure LO on the reservoir independently of the attitude of the aircraft relative to gravity.

[0059] Example 3. A lubrication system according to any one or more of the above embodiments, wherein the inlet port of the IC is configured to receive LO at a first pressure P1, wherein the overflow port is configured to distribute LO at a second pressure P2, wherein the supply port is configured to distribute LO at a third pressure P3, and wherein P1 is substantially equal to the sum of P2 and P3.

[0060] Example 4. A lubrication system according to any one or more of the above embodiments, wherein the reservoir includes a first outlet port and a second outlet port, wherein the first outlet port and the second outlet port are disposed on substantially opposite sides of the reservoir, and wherein the inlet port of the IC is in fluid communication with the first outlet port and the second outlet port of the reservoir.

[0061] Example 5. A lubrication system according to any one or more of the above embodiments, wherein the first outlet port is connected to the IC via a first fluid channel, wherein the second outlet port is connected to the IC via a second fluid channel, wherein the first fluid channel includes a first return oil pump, and the second fluid channel includes a second return oil pump, wherein the first fluid channel and the second fluid channel are in fluid communication with an oil-gas separator configured to remove air from the LO, and wherein the oil-gas separator is configured to provide the LO to the IC and discharge air to the external environment.

[0062] Example 6. A lubrication system according to any one or more of the above embodiments, wherein the LO tank includes a replenishment fluid circuit that is in fluid communication with the oil-gas separator and is configured to supply LO from the LO tank to the oil-gas separator.

[0063] Example 7. A lubrication system according to any one or more of the above embodiments, wherein the IC has a first internal volume, wherein the LO tank has a second internal volume, and wherein the first internal volume is smaller than the second internal volume.

[0064] Example 8. A lubrication system according to any one or more of the above embodiments, wherein the IC is at least partially disposed within the LO tank.

[0065] Example 9. A lubrication system according to any one or more of the above embodiments, wherein the lubrication system is modified in the aircraft.

[0066] Example 10. An aircraft comprising: a device including a reservoir configured to receive lubricating oil (LO); a lubrication system in fluid communication with the reservoir and configured to continuously supply LO to the reservoir at a substantially constant pressure independent of the aircraft's attitude relative to gravity.

[0067] Example 11. An aircraft according to any one or more of the above embodiments, wherein the lubrication system includes an inlet chamber (IC) in fluid communication with one or more outlet ports of the reservoir, wherein the IC is configured to receive LO from the one or more outlet ports of the reservoir at a first pressure P1, wherein the IC includes: an overflow port in fluid communication with an LO tank configured to receive overflow LO from the IC, the overflow port being configured to distribute the overflow LO to the LO tank at a second pressure P2; and a supply port configured to supply LO to the reservoir at a third pressure P3, wherein P1 is substantially equal to the sum of P2 and P3.

[0068] Example 12. An aircraft according to any one or more of the above embodiments, wherein the overflow port is configured to substantially continuously deliver LO flow to the LO box during operation of the aircraft.

[0069] Example 13. An aircraft according to any one or more of the above embodiments, wherein P2 is variable and P3 is substantially constant.

[0070] Example 14. An aircraft according to any one or more of the above embodiments, wherein the lubrication system comprises: an oil-gas separator configured to remove air from the LO after exiting the reservoir; a supplemental fluid circuit configured to supply LO from the LO tank of the lubrication system to the oil-gas separator; and a fluid passage fluidly connecting the oil-gas separator to the oil inlet chamber (IC) of the lubrication system and configured to provide LO to the IC.

[0071] Example 15. An aircraft according to any one or more of the above embodiments, wherein the substantially constant pressure LO supplied by the lubrication system to the reservoir is configured to deviate from the desired pressure by less than 1 pound per square inch (PSI) during operation of the aircraft.

[0072] Example 16. An aircraft according to any one or more of the above embodiments, wherein the reservoir includes a first outlet port and a second outlet port, wherein the first outlet port and the second outlet port are disposed on substantially opposite sides of the reservoir, and wherein the lubrication system is in fluid communication with the first outlet port and the second outlet port of the reservoir.

[0073] Example 17. The aircraft according to any one or more of the above embodiments, wherein the lubrication system is modified in the aircraft.

[0074] Example 18. A method of installing a lubrication system in an aircraft, the method comprising: providing an oil inlet chamber (IC) in the aircraft such that an inlet port of the IC is in fluid communication with a reservoir of lubricating oil (LO) exiting the aircraft; fluidly connecting an overflow port of the IC to a LO tank of the aircraft; and fluidly connecting a supply port of the IC to the reservoir, the IC being configured to supply LO to the reservoir.

[0075] Example 19. According to any one or more of the methods described in the above examples, wherein the IC is installed such that the IC is at least partially installed in the LO box.

[0076] Example 20. The method described in any one or more of the above examples, wherein the installation of the IC is performed as a retrofit installation in an existing aircraft.

Claims

1. A lubrication system for aircraft, characterized in that, The lubrication system includes: Lubricating oil tank, the lubricating oil tank being configured to operate under a first internal pressure; and An oil inlet chamber, configured to operate at a second internal pressure greater than the first internal pressure, the oil inlet chamber comprising: An inlet port is configured to receive lubricating oil from a reservoir of equipment of the aircraft, wherein the reservoir includes a first outlet port and a second outlet port, wherein the first outlet port and the second outlet port are located on opposite sides of the reservoir, and wherein the inlet port of the oil inlet chamber is in fluid communication with the first outlet port and the second outlet port of the reservoir. An overflow port, which is in fluid communication with the lubricating oil tank; and A supply port, which is in fluid communication with the reservoir and is configured to supply lubricating oil to the reservoir; A replenishing fluid circuit, the replenishing fluid circuit having a first replenishing fluid channel and a second replenishing fluid channel, the first replenishing fluid channel and the second replenishing fluid channel being in fluid communication with the lubricating oil tank on the opposite side from the lubricating oil tank; and An oil-gas separator, which is fluidly connected to a first fluid passage and a second fluid passage, as well as a first supplementary fluid passage and a second supplementary fluid passage, and wherein the oil-gas separator is configured to provide the lubricating oil to the oil inlet chamber and to discharge air to the external environment.

2. The lubrication system according to claim 1, characterized in that, The oil inlet chamber is configured to maintain a constant pressure of lubricating oil on the reservoir, independent of the aircraft's attitude relative to gravity.

3. The lubrication system according to claim 1, characterized in that, The inlet port of the oil inlet chamber is configured to receive lubricating oil under a first pressure P1, the overflow port is configured to dispense lubricating oil under a second pressure P2, the supply port is configured to dispense lubricating oil under a third pressure P3, and P1 is equal to the sum of P2 and P3.

4. The lubrication system according to claim 1, characterized in that, The first outlet port is connected to the oil inlet chamber via the first fluid channel, and the second outlet port is connected to the oil inlet chamber via the second fluid channel. The first fluid channel includes a first return oil pump, and the second fluid channel includes a second return oil pump. The first fluid channel and the second fluid channel are in fluid communication with an oil-gas separator configured to remove air from the lubricating oil.

5. The lubrication system according to claim 1, characterized in that, The oil inlet chamber has a first internal volume, the lubricating oil tank has a second internal volume, and the first internal volume is smaller than the second internal volume.

6. The lubrication system according to claim 1, characterized in that, The oil inlet chamber is at least partially located within the lubricating oil tank.

7. The lubrication system according to claim 1, characterized in that, The lubrication system mentioned above was modified for use in the aircraft.

8. An aircraft, characterized in that, include: Lubrication system, the lubrication system comprising: Lubricating oil tank, the lubricating oil tank being configured to operate under a first internal pressure; and An oil inlet chamber, configured to operate at a second internal pressure greater than the first internal pressure, the oil inlet chamber comprising: An inlet port is configured to receive lubricating oil from a reservoir of equipment of the aircraft, wherein the reservoir includes a first outlet port and a second outlet port, wherein the first outlet port and the second outlet port are located on opposite sides of the reservoir, and wherein the inlet port of the oil inlet chamber is in fluid communication with the first outlet port and the second outlet port of the reservoir. An overflow port, which is in fluid communication with the lubricating oil tank; and A supply port, which is in fluid communication with the reservoir and is configured to supply lubricating oil to the reservoir; A replenishing fluid circuit, the replenishing fluid circuit having a first replenishing fluid channel and a second replenishing fluid channel, the first replenishing fluid channel and the second replenishing fluid channel being in fluid communication with the lubricating oil tank on the opposite side from the lubricating oil tank; An oil-gas separator, which is fluidly connected to a first fluid passage and a second fluid passage, as well as a first supplementary fluid passage and a second supplementary fluid passage, and wherein the oil-gas separator is configured to provide the lubricating oil to the oil inlet chamber and to discharge air to the external environment.

9. The aircraft according to claim 8, characterized in that, The oil inlet chamber is configured to receive lubricating oil from the first outlet port and the second outlet end of the reservoir under a first pressure P1, wherein the oil inlet chamber includes: An overflow port, which is in fluid communication with the lubricating oil tank, the lubricating oil tank being configured to receive overflow lubricating oil from the oil inlet chamber, and the overflow port being configured to distribute the overflow lubricating oil back into the lubricating oil tank under a second pressure P2; and A supply port, configured to supply lubricating oil to the reservoir under a third pressure P3. Where P1 equals the sum of P2 and P3.

10. The aircraft according to claim 9, characterized in that, The overflow port is configured to continuously deliver lubricating oil to the lubricating oil tank during the operation of the aircraft.

11. The aircraft according to claim 9, characterized in that, Where P2 is variable, and P3 is constant.

12. The aircraft according to claim 8, characterized in that, The lubricating oil supplied to the reservoir by the lubrication system at a constant pressure is configured to deviate from the desired pressure by less than 1 pound per square inch during the operation of the aircraft.

13. The aircraft according to claim 8, characterized in that, The lubrication system mentioned above was modified for use in the aircraft.

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