Patent ID: 12234767

DETAILED DESCRIPTION

The present disclosure is directed to an aircraft engine lubrication system configured to provide a lubricant (e.g., “oil”) that functions to lubricate and cool engine components such as gears, bearings, and journal bearings or static elements such as internal cavity walls to avoid overheating. Embodiments of the present disclosure system are configured such that a portion of the system oil is passed through the de-aerator during a given flow cycle and the remainder of the oil is passed back to the oil tank.

FIG.3illustrates a gas turbine engine20that includes in serial flow communication a fan22through which ambient air is propelled, a compressor section24for pressurizing the air, a combustor26in which the compressed air is mixed with fuel and ignited for generating an annular stream of hot combustion gases, and a turbine section28for extracting energy from the combustion gases. The present disclosure may be used within conventional through-flow or reverse flow gas turbine engines, gas turbine engine types such as turbofan engines, turboprop engines, turboshaft engines, and internal combustion engines as well.

The engine20further comprises one or more fluid systems, such as a lubrication system30that circulates lubricant to both lubricate and cool components; e.g., bearings, gears (e.g., within a gearbox), and other components. As will be detailed herein, a lubrication system30may include a number of different components including a lubricant pump, a lubricant tank, a de-aerator, a scavenge pump and the like. Embodiments of the present disclosure system30, including the lubrication system components that may be included in each, are detailed hereinafter.

FIGS.4and5diagrammatically illustrate non-limiting embodiments of a present disclosure aircraft engine lubrication system30. The system30embodiments may include components including an oil tank32, a pressure pump34, a make-up pump36, a de-aerator38, a blowdown valve40, an oil delay valve42, a pressure regulating valve (PRV)44, a scavenge pump46, and one or more fluid filters48, and/or combination filter/coolers50.

The lubrication system30is configured to service one or more engine components, including but not limited to, gears, bearings, journal bearings, or static elements such as internal cavity walls. The present disclosure system30is not limited to servicing any particular type of engine component. To facilitate the description herein, the engine components will be referred to generically as Component1and Component2.

The oil tank32is a reservoir configured to hold a volume of lubricant. The oil tank32has at least one fluid inlet52, at least one fluid outlet54, and a gas (e.g., air) vent56. The size and configuration of the oil tank32may vary depending on the system30; e.g., the fluid volume capacity of the oil tank32may vary depending on the application, and the geometric configuration of the oil tank32may vary depending on the application. The diagrammatic representation in the FIGURES of the oil tank32as a square vessel is for diagrammatic purposes only. Typically, the fluid inlet52is disposed gravitationally above the fluid outlet54.

The pressure pump34and the make-up pump36may each be a positive displacement pump such as a geared pump. The pressure pump34and/or the make-up pump36may be in mechanical communication with the engine; e.g., via a gearbox. In those embodiments that include a scavenge pump46, the scavenge pump46may also be a mechanically driven positive displacement pump. The present disclosure is not limited to any particular type of pressure pump34, make-up pump36, or scavenge pump46; e.g., electrically driven positive placement pumps may be used. In those embodiments that include a make-up pump36in the form of a jet pump, the jet pump may utilize a Venturi effect to generate suction and draw fluid through the pump.

The de-aerator38passively or actively causes a separation of entrained air from the oil passing to the de-aerator38from the component. An example of a passive de-aerator as that term is used herein is a de-aerator that does not use an impeller, but rather uses for example a helical passage that allows centrifugal force to separate oil from air. Passive de-aerators are known, and the present disclosure is not limited to any particular type. An example of an active de-aerator as that term is used herein is a de-aerator that uses an impeller (either driven or freewheeling). Active de-aerators are known, and the present disclosure is not limited to any particular type. The de-aerator38includes an inlet58through which fluid (that may have a substantial percentage of air, entrained and/or mixed with the oil) may pass, a gas outlet60through which entrained air separated from the inlet fluid may pass, and a liquid outlet62through which fluid less the removed entrained air may pass. The efficiency of the de-aerator38(i.e., the degree to which it removed entrained air) may vary. As will be detailed herein, in some embodiments a de-aerator38may be a static (i.e., non-powered) type or may be an active type which is mechanically, electrically, or hydraulically powered.

A blowdown valve40as may be used in a system30embodiment is a directional valve that permits one-way passage of a fluid. Non-limiting examples of such valves include ball valves, puppet valves, and the like.

A filter48as may be used in a system30embodiment is a device configured to remove contaminants (e.g., unwanted particulate matter) from the lubricant flow.

A filter/cooler50as may be used in a system30embodiment includes a filter element as described above and may be further configured to remove thermal energy from the lubricant flow.

Components within the present disclosure system30embodiments may be connected to one another by a respective fluid line; e.g., a pipe, a tube, or the like configured to contain and permit passage of a fluid therethrough. The term “in fluid communication” is used herein to mean that a fluid line extends between the named components and is configured to contain a fluid flow between the components.

FIG.4diagrammatically illustrates an embodiment of a present disclosure aircraft engine lubrication system30. In this embodiment, the system30includes an oil tank32, a pressure pump34, a make-up pump36, and a de-aerator38.FIG.4also shows a scavenge pump46that may optionally be included.FIG.4diagrammatically illustrates the lubrication system30in communication with two engine components, namely Component1and Component2. The inlet64of the make-up pump36is in fluid communication with the outlet54of the oil tank32and the outlet66of the make-up pump36is in fluid communication with the inlet68of the pressure pump34. The outlet70of the pressure pump34is in fluid communication with an inlet72of Component1and with an inlet74of Component2. More specifically, the outlet70of the pressure pump34is in fluid communication with a fluid line76that intersects with a supply fluid line78that extends between Component1and Component2. A first portion78A of the supply fluid line78extends from the intersection to Component1, and a second portion78B of the supply fluid line78extends from the intersection to Component2. The outlet80of Component2is in fluid communication with a second inlet52B of the oil tank32. The outlet82of Component1is in fluid communication with the de-aerator38. As indicated above, a scavenge pump46may be included (e.g., in-line) to facilitate the flow of oil from the outlet82of Component1to the de-aerator38. In this embodiment, the de-aerator38may be a static de-aerator or an active de-aerator. The gas outlet60of the de-aerator38is in fluid communication with a first inlet52A of the oil tank32. The liquid outlet62of the de-aerator38is in fluid communication with the fluid line84extending between the outlet66of the make-up pump36and the inlet68of the pressure pump34.

In the operation of the present disclosure aircraft engine lubrication system30shown inFIG.4, oil is pumped by the pressure pump34into both Component1and Component2. Within the interaction between the oil and the respective engine component, air may become entrained within the oil. Hence, the generic description of oil being pumped into “Component1” or “Component2” contemplates that during the interaction between the oil and a component/cavity, air may become entrained within the oil. It should be noted, however, that the entrainment of air within oil may occur elsewhere within the lubrication system30other than within a component/cavity.

Oil exits the outlet80of Component2and passes to the second inlet52B of the oil tank32. In this embodiment, the oil passing between Component2and the oil tank32is not subject to purposeful de-aeration. Hence, the oil entering the oil tank32from Component2may include some amount of entrained air. The aforesaid entrained air may separate from the oil while that oil dwells within the oil tank32. As stated above, the oil tank32includes a gas vent56that permits air within the oil tank32to be vented out of the lubrication system30.

Oil exits the outlet82of Component1and is passed to the inlet58of the de-aerator38. As indicated above, a scavenge pump46may be included (e.g., in-line) to facilitate the flow of oil from the outlet82of Component1to the de-aerator38.

The de-aerator38passively or actively causes a separation of entrained air from the oil passing to the de-aerator38from Component1. The separated air passes from the de-aerator gas outlet60to the first inlet52A of the oil tank32and into the oil tank32. The separated oil (i.e., the oil that has been processed to remove at least some of the entrained air) passes from the de-aerator liquid outlet62to the fluid line84extending between the outlet66of the make-up pump36and the inlet68of the pressure pump34. The pressure pump34, in turn, pumps the oil from Component1back into the system30to repeat the cycle.

In the manner described above, a portion of the system oil is passed through the de-aerator38during a given flow cycle and the remainder of the oil is passed back to the oil tank32. The make-up pump36is operated to impose a direction of flow from the de-aerator liquid outlet62to the inlet68of the pressure pump34and thereby avoid liquid flow into the oil tank32from the de-aerator liquid outlet62. A benefit of this system30embodiment is that it reduces the dwell time induced volume of oil within the oil tank32. Another benefit of this system30embodiment is that it forms a quasi-closed loop for oil flow through Component1. As detailed above, in an aircraft application, the gravity vector for oil in a tank or cavity (e.g., oil tank32or Component1) may not always point towards the tank/cavity outlet. If the outlet of a tank/cavity is not covered in oil (e.g., because of the gravitational orientation of the oil-a scenario that may be referred to as “loosing”), air may be undesirably drawn into the pressure pump inlet68and the flow of oil to Component1and2impeded. The oil flow loop through Component1that bypasses the oil tank32in this embodiment mitigates the possibility that the pump inlet68ingests air in adverse acceleration scenarios.

FIG.5diagrammatically illustrates an embodiment of a present disclosure aircraft engine lubrication system30. In this embodiment, the system30includes an oil tank32, Component1, Component2, blowdown valves40A,40B, a first de-aerator38A, a second de-aerator38B, a make-up pump36in the form of a jet pump, a pressure pump34, an oil delay valve42, a pressure regulating valve (PRV)44, a first scavenge pump46A, a second scavenge pump46B, and one or more oil filter48, and/or combination filter/coolers50. Unless specifically stated herein, the system30embodiment shown inFIG.5does not require all of the components shown inFIG.5; e.g., more, or fewer filters48may be used, one or both scavenge pumps46may not be included, and the like. In addition, the jet pump36may provide several benefits (e.g., lower cost, less weight, power efficiency, and the like) but is not specifically required; e.g., a positive displacement make-up pump36may be used in place of the jet pump.

In the system30diagrammatically shown inFIG.5, the outlet54of the oil tank32is in fluid communication with the inlet64of the jet pump36and the outlet66of the jet pump36is in fluid communication with the inlet68of the pressure pump34. The outlet70of the pressure pump34is in fluid communication with an inlet72of Component1and an inlet74of Component2. More specifically, the outlet70of the pressure pump34is in fluid communication with a fluid line76that intersects with a supply fluid line78that extends between Component1and Component2. A first portion78A of the supply fluid line extends from the intersection to Component1, and a second portion78B of the supply fluid line78extends from the intersection to Component2. The PRV44is disposed across the pressure pump34and in communication with the jet pump36. A filter/cooler50is disposed in-line with the outlet70of the pressure pump34. The outlet80of Component2is in fluid communication with the second de-aerator38B. The second scavenge pump46B is shown disposed in-line between the outlet80of Component2and the inlet58B of the second de-aerator38B. The gas outlet60B of the second de-aerator38B is in fluid communication with a second inlet52B of the oil tank32. The liquid outlet62B of the second de-aerator38B is in fluid communication with a third inlet52C of the oil tank32. A second blowdown valve40B is in fluid communication with the fluid line86that extends between the outlet80of Component2and the second scavenge pump46B, and a fourth inlet52D of the oil tank32. InFIG.5, the oil delay valve42is disposed in-line within the second portion78B of the supply fluid line78.FIG.5also shows in phantom line that the oil delay valve42may alternatively be disposed in the fluid line76extending between the pressure pump34and the supply fluid line78or may be disposed in the first portion78A of the supply fluid line78. The outlet82of Component1is in fluid communication with the inlet58A first de-aerator38A. The gas outlet60A of the first de-aerator38A is in fluid communication with a first inlet52A of the oil tank32via a fluid line88. The liquid outlet62A of the first de-aerator38A is in fluid communication with an inlet of the jet pump36. A filter48may be disposed in-line with the fluid line90extending between the fluid outlet62A of the first de-aerator38A and the inlet of the jet pump36. The system30shown inFIG.5shows the first scavenge pump46A disposed in-line between the outlet82of Component1and the first de-aerator38A. A first blowdown valve40A may be included having an inlet disposed in fluid communication with the fluid line92extending between the outlet82of Component1and the first de-aerator38A, and an outlet in fluid communication with the fluid line94extending to the fifth inlet52E of the oil tank32.FIG.5shows the inlet line of the first blowdown valve disposed upstream of the first scavenge pump46A.FIG.5also shows alternatives (in dashed line), including the first blowdown valve40A disposed downstream of the first scavenge pump46A, or downstream of both the first scavenge pump46A and a filter48(shown as optional).

In the operation of the present disclosure system30shown inFIG.5, oil is pumped by the pressure pump34into both Component1and Component2. Oil exiting the pressure pump34passes through the filter/cooler50prior to passing into Component1and Component2. The PRV44disposed across the pressure pump34is used to regulate the fluid pressure across the pressure pump34. Oil entering the second portion78B of the supply fluid line78for passage to Component2encounters the oil delay valve42. The oil delay valve42is operable to stop the oil flow to Component2under certain circumstances; e.g., in negative gravity circumstances, and the like. In fact, the oil delay valve42may be utilized to provide several benefits. For example, the oil delay valve42may be operated to a closed configuration to prevent oil seepage out of Component2under certain operational circumstances such as may occur in an acceleration from shutdown to ground idle and deacceleration. When the oil delay valve42is closed preventing the flow of oil to Component2, the system30may be described as being a quasi-closed loop for Component1. When the system30is configured as a quasi-closed loop for Component1(i.e., when the oil delay valve42is closed), the entire capacity of the pressure pump34is selectively available to Component1. As a result, a higher oil flow/oil pressure can be selectively maintained relative to Component1.

When there is a flow of oil through to Component2, the oil exits the Component2outlet80and passes to the second de-aerator38B. The oil flow between Component2and the second de-aerator38B may be assisted by the second scavenge pump46B. The second de-aerator38B is shown as a static de-aerator. Entrained air separated within the second de-aerator38B is passed into the oil tank32via the second inlet52B of the oil tank32. The separated oil is passed into the oil tank32via the third inlet52C of the oil tank32. The second blowdown valve40B (disposed between the outlet80of Component2and the fourth inlet52D of the oil tank32) permits air to escape into the oil tank32.

Oil exiting the outlet82of Component1passes to the first de-aerator38A. The oil flow between Component1and the first de-aerator38A may be assisted by the first scavenge pump46A. The first de-aerator38A may be a static de-aerator or an active de-aerator. Entrained air separated within the first de-aerator38A is passed into the oil tank32via the first inlet52A of the oil tank32. The separated oil is passed from the liquid outlet62A of the first de-aerator38A to the jet pump36. A filter48may be disposed in-line between the first de-aerator38A and the jet pump36.

The jet pump36is operated to impose a direction of flow from the de-aerator liquid outlet62to the inlet68of the pressure pump34and thereby avoid liquid flow into the oil tank32from the de-aerator liquid outlet62. At high altitudes, a gear-type pump may be subject to cavitation as the oil tank pressure is likely lower than the cavitation threshold. Jet pumps, in contrast, are not subject to cavitation under normal operation. Hence, in a high-altitude operation a jet pump may provide operational advantages.

In the system30embodiment shown inFIG.5(like that shown inFIG.4), only a portion of the system oil is passed back into the oil tank32during a given flow cycle. Oil from the jet pump36and oil from the liquid outlet62A of the first de-aerator38A are provided to the pressure pump34at a flow rate that substantially maintains a uniform collective oil flow within the lubrication system30. Depending on the operating parameters, oil may cycle through the PRV44and into the jet pump36to regulate the fluid pressure across the pressure pump34.

A benefit of this system30embodiment is that it reduces the dwell time induced volume of oil within the oil tank32, given that only a portion of the collective oil flow is returned to the oil tank32. Another benefit of this system30embodiment, including the oil delay valve42, is that it forms a closed loop for oil flow (e.g., in a negative gravity condition) through Component1and the potential for loosing is mitigated. Moreover, because the pressure pump34volumetric capacity is greater than the flow passing through the first de-aerator38A, in a negative gravity condition the pressure pump34will provide an air-oil mixture within the system30. Although not passing 100% de-aerated oil, the partial de-aeration in the Component1loop allows 100% of what is scavenged from Component1to be cycled within loop.

A present disclosure aircraft engine lubrication system30embodiment like that shown inFIG.5and described herein, may be used to protect an oil sensitive cavity/component, or a high oil cavity/component consumer, for bigger impact on the engine. Also, the isolation of an oil sensitive cavity/component (e.g., Component1in theFIG.5embodiment) by an oil delay valve in a system30where the de-aerator38only sees the flow from the isolated cavity/component permits the de-aerator38efficiency to be improved in contrast to a system wherein all of the return oil flow must pass through a single de-aerator prior to returning to the pressure pump.

Embodiments of the present disclosure may be used to retrofit existing lubrication systems.

While the principles of the disclosure have been described above in connection with specific apparatuses and methods, it is to be clearly understood that this description is made only by way of example and not as limitation on the scope of the disclosure. Specific details are given in the above description to provide a thorough understanding of the embodiments. However, it is understood that the embodiments may be practiced without these specific details.

It is noted that the embodiments may be described as a process which is depicted as a flowchart, a flow diagram, a block diagram, etc. Although any one of these structures may describe the operations as a sequential process, many of the operations can be performed in parallel or concurrently. In addition, the order of the operations may be rearranged. A process may correspond to a method, a function, a procedure, a subroutine, a subprogram, etc.

The singular forms “a,” “an,” and “the” refer to one or more than one, unless the context clearly dictates otherwise. For example, the term “comprising a specimen” includes single or plural specimens and is considered equivalent to the phrase “comprising at least one specimen.” The term “or” refers to a single element of stated alternative elements or a combination of two or more elements unless the context clearly indicates otherwise. As used herein, “comprises” means “includes.” Thus, “comprising A or B,” means “including A or B, or A and B,” without excluding additional elements.

It is noted that various connections are set forth between elements in the present description and drawings (the contents of which are included in this disclosure by way of reference). It is noted that these connections are general and, unless specified otherwise, may be direct or indirect and that this specification is not intended to be limiting in this respect. Any reference to attached, fixed, connected or the like may include permanent, removable, temporary, partial, full and/or any other possible attachment option.

No element, component, or method step in the present disclosure is intended to be dedicated to the public regardless of whether the element, component, or method step is explicitly recited in the claims. No claim element herein is to be construed under the provisions of 35 U.S.C. 112(f) unless the element is expressly recited using the phrase “means for.” As used herein, the terms “comprise”, “comprising”, or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus.

While various inventive aspects, concepts and features of the disclosures may be described and illustrated herein as embodied in combination in the exemplary embodiments, these various aspects, concepts, and features may be used in many alternative embodiments, either individually or in various combinations and sub-combinations thereof. Unless expressly excluded herein all such combinations and sub-combinations are intended to be within the scope of the present application. Still further, while various alternative embodiments as to the various aspects, concepts, and features of the disclosures—such as alternative materials, structures, configurations, methods, devices, and components, and so on—may be described herein, such descriptions are not intended to be a complete or exhaustive list of available alternative embodiments, whether presently known or later developed. Those skilled in the art may readily adopt one or more of the inventive aspects, concepts, or features into additional embodiments and uses within the scope of the present application even if such embodiments are not expressly disclosed herein. For example, in the exemplary embodiments described above within the Detailed Description portion of the present specification, elements may be described as individual units and shown as independent of one another to facilitate the description. In alternative embodiments, such elements may be configured as combined elements. It is further noted that various method or process steps for embodiments of the present disclosure are described herein. The description may present method and/or process steps as a particular sequence. However, to the extent that the method or process does not rely on the particular order of steps set forth herein, the method or process should not be limited to the particular sequence of steps described. As one of ordinary skill in the art would appreciate, other sequences of steps may be possible. Therefore, the particular order of the steps set forth in the description should not be construed as a limitation.