U.S. patent application number 17/038361 was filed with the patent office on 2021-07-08 for lubrication system for gas turbine engines.
The applicant listed for this patent is Raytheon Technologies Corporation. Invention is credited to Katherine A. Knapp Carney, Francis Parnin, Matthew D. Teicholz, Richard Alan Weiner.
Application Number | 20210207533 17/038361 |
Document ID | / |
Family ID | 1000005478593 |
Filed Date | 2021-07-08 |
United States Patent
Application |
20210207533 |
Kind Code |
A1 |
Teicholz; Matthew D. ; et
al. |
July 8, 2021 |
LUBRICATION SYSTEM FOR GAS TURBINE ENGINES
Abstract
A method of controlling lubrication flow to a first engine
component, a second engine component and a lubrication tank of a
gas turbine engine according to an example of the present
disclosure includes, among other things, determining more than one
condition experienced by the gas turbine engine, comparing with a
processor on a controller the more than one condition against an
engine performance model stored in memory on the controller,
wherein the engine performance model includes stored relationship
values between the more than one condition and a position of a
scheduling valve, the scheduling valve disposed between the
lubricant tank and the first engine component and between the
lubricant tank and the second engine component, pumping a lubricant
from the lubricant tank through a conduit to the scheduling valve
using a pump, and controlling the position of the scheduling valve
to vary a flow of the lubricant to two or more of the first engine
component, the second engine component and the lubrication tank
based upon the comparing of the more than one condition experienced
by the gas turbine engine.
Inventors: |
Teicholz; Matthew D.;
(Mystic, CT) ; Parnin; Francis; (Suffield, CT)
; Weiner; Richard Alan; (Farmington, CT) ; Knapp
Carney; Katherine A.; (Tolland, CT) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Raytheon Technologies Corporation |
Farmington |
CT |
US |
|
|
Family ID: |
1000005478593 |
Appl. No.: |
17/038361 |
Filed: |
September 30, 2020 |
Related U.S. Patent Documents
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
|
|
15875279 |
Jan 19, 2018 |
10830140 |
|
|
17038361 |
|
|
|
|
14697223 |
Apr 27, 2015 |
9874145 |
|
|
15875279 |
|
|
|
|
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
F02C 7/36 20130101; F02C
7/14 20130101; F02C 3/107 20130101; F02C 7/06 20130101; F01D 25/20
20130101; F16H 57/0435 20130101; F16N 2250/08 20130101; F05D
2260/53 20130101; F01M 1/16 20130101; F01M 2013/0472 20130101 |
International
Class: |
F02C 7/06 20060101
F02C007/06; F01D 25/20 20060101 F01D025/20; F02C 7/14 20060101
F02C007/14; F01M 1/16 20060101 F01M001/16; F16H 57/04 20060101
F16H057/04; F02C 3/107 20060101 F02C003/107; F02C 7/36 20060101
F02C007/36 |
Claims
1-30. (canceled)
31. A turbofan gas turbine engine, comprising: a fan section
including a fan and an outer housing surrounding the fan to define
a bypass duct, and a fan pressure ratio of less than 1.45 across
the fan blade alone at a cruise condition at 0.8 Mach and 35,000
feet; a compressor section including a first compressor and a
second compressor; a combustion section including a combustor
downstream of the compressor section; a turbine section including a
fan drive turbine and a second turbine; a lubrication system
including a pump that moves a lubricant and a lubricant tank that
stores the lubricant; a first engine component and a second engine
component each requiring lubrication from the lubricant, wherein
the first engine component is a fan drive gear system that allows
the fan to rotate at a different angular speed from a spool; a
conduit between the lubricant tank and the first engine component
and between the lubricant tank and the second engine component; a
scheduling valve positioned in the conduit between the lubricant
tank, and the first engine component and the second engine
component; and a controller including a memory and a processor that
controls the scheduling valve, wherein the memory includes stored
relationship values between more than one condition experienced by
the turbofan gas turbine engine in operation and a position of the
scheduling valve, and wherein the controller commands the
scheduling valve to vary a flow of the lubricant to the first
engine component, the second engine component and the lubricant
tank in response to the more than one condition.
32. The turbofan gas turbine engine as recited in claim 31, wherein
the spool is a low spool including a shaft that interconnects the
fan drive gear system and the fan drive turbine.
33. The turbofan gas turbine engine as recited in claim 32, wherein
the more than one condition includes a first condition relating to
the angular speed of the fan.
34. The turbofan gas turbine engine as recited in claim 33, wherein
the first condition includes a calculated engine torque, and
wherein the calculated engine torque includes a calculated torque
for the fan, the fan drive gear system or the low spool.
35. The turbofan gas turbine engine as recited in claim 32, wherein
the fan drive gear system comprises an epicyclic gear train.
36. The turbofan gas turbine engine as recited in claim 35, wherein
the fan drive turbine drives the first compressor and the fan drive
gear system.
37. The turbofan gas turbine engine as recited in claim 31, wherein
the more than one condition includes two or more of: a calculated
engine torque, an engine startup condition of the turbofan gas
turbine engine, an altitude of the turbofan gas turbine engine, a
vibration level of the turbofan gas turbine engine, the cruise
condition, a weight on wheels condition of an aircraft on which the
turbofan gas turbine engine is mounted, and a burner pressure
condition of the combustor.
38. The turbofan gas turbine engine as recited in claim 37, wherein
the scheduling valve is moveable between a plurality of positions
including first and second positions, the controller commands the
scheduling valve to communicate the lubricant to the first
component but not the second component in the first position, and
the controller commands the scheduling valve to communicate the
lubricant to both the first and second components in the second
position.
39. The turbofan gas turbine engine as recited in claim 38, wherein
the more than one condition includes the calculated engine torque,
and wherein the calculated engine torque includes a calculated
torque for the fan.
40. The turbofan gas turbine engine as recited in claim 39, wherein
the plurality of positions includes a third position, and the
controller commands the scheduling valve to communicate the
lubricant to the second component but not the first component in
the third position.
41. The turbofan gas turbine engine as recited in claim 40, wherein
the plurality of positions includes a fourth position, and the
controller commands the scheduling valve to communicate the
lubricant to the lubricant tank but not the first and second
components in the fourth position.
42. The turbofan gas turbine engine as recited in claim 37,
comprising a plurality of sensors that each provide data about a
state of the turbofan gas turbine engine that indicates one of the
more than one condition.
43. The turbofan gas turbine engine as recited in claim 42, wherein
the more than one condition includes the vibration level, and the
vibration level corresponds to a vibration level of the fan drive
gear system.
44. The turbofan gas turbine engine as recited in claim 43, wherein
the plurality of sensors includes a vibration sensor that is used
to gather data indicating the vibration level of the fan drive gear
system.
45. The turbofan gas turbine engine as recited in claim 44, wherein
the vibration sensor is an accelerometer.
46. The turbofan gas turbine engine as recited in claim 44, wherein
the vibration sensor is positioned in the fan drive gear
system.
47. The turbofan gas turbine engine as recited in claim 46, wherein
the vibration sensor is an accelerometer.
48. The turbofan gas turbine engine as recited in claim 42, wherein
the more than one condition includes the calculated engine torque,
and the calculated engine torque includes a calculated torque for
the fan.
49. The turbofan gas turbine engine as recited in claim 48, wherein
the spool is a low spool including a shaft that interconnects the
fan drive gear system and the fan drive turbine.
50. The turbofan gas turbine engine as recited in claim 49, wherein
the plurality of sensors includes an RPM sensor.
51. The turbofan gas turbine engine as recited in claim 49, wherein
the more than one condition includes the altitude of the turbofan
gas turbine engine.
52. The turbofan gas turbine engine as recited in claim 51, wherein
the more than one condition includes the cruise condition.
53. The turbofan gas turbine engine as recited in claim 49, wherein
the more than one condition includes the burner pressure
condition.
54. The turbofan gas turbine engine as recited in claim 53, wherein
the more than one condition includes the engine startup condition,
the altitude of the turbofan gas turbine engine, the cruise
condition, the vibration level of the turbofan gas turbine engine,
and the weight on wheels condition.
55. The turbofan gas turbine engine as recited in claim 54, wherein
the vibration level corresponds to a vibration level of the fan
drive gear system, and the plurality of sensors includes a
vibration sensor that is used to gather data indicating the
vibration level of the fan drive gear system.
56. The turbofan gas turbine engine as recited in claim 55, wherein
the vibration sensor is positioned in the fan drive gear
system.
57. The turbofan gas turbine engine as recited in claim 56, wherein
the vibration sensor is an accelerometer.
58. The turbofan gas turbine engine as recited in claim 53, wherein
the lubrication system includes a de-aerator, a filter and a cooler
each between the lubricant tank and the first engine component, and
each between the lubricant tank and the second engine
component.
59. The turbofan gas turbine engine as recited in claim 58, wherein
the scheduling valve is moveable between a plurality of positions
including first, second, third and fourth positions, wherein the
controller commands the scheduling valve to communicate the
lubricant to the first component but not the second component in
the first position, wherein the controller commands the scheduling
valve to communicate the lubricant to both the first and second
components in the second position, wherein the controller commands
the scheduling valve to communicate the lubricant to the second
component but not the first component in the third position, and
wherein the controller commands the scheduling valve to communicate
the lubricant to the lubricant tank but not the first and second
components in the fourth position.
60. The turbofan gas turbine engine as recited in claim 59, wherein
the pump is driven by a rotating component of the gas turbine
engine, and the pump supplies a varying flow of the lubricant to
the scheduling valve in operation.
Description
CROSS-REFERENCE TO RELATED APPLICATION
[0001] The present disclosure in a continuation of U.S. patent
application Ser. No. 15/875,279 filed Jan. 19, 2018, which is a
continuation of U.S. patent application Ser. No. 14/697,223 filed
Apr. 27, 2015, now U.S. Pat. No. 9,874,145 granted Jan. 23,
2018.
BACKGROUND OF THE INVENTION
[0002] This disclosure generally relates to gas turbine engines
and, more particularly, relates to a lubrication system for gas
turbine engine components.
[0003] Many modern aircraft, as well as other vehicles and
industrial processes, employ gas turbine engines for generating
energy and propulsion. Such engines include a fan, compressor,
combustor and turbine provided in serial fashion, forming an engine
core and arranged along a central longitudinal axis. Air enters the
gas turbine engine through the fan and is pressurized in the
compressor. This pressurized air is mixed with fuel in the
combustor. The fuel-air mixture is then ignited, generating hot
combustion gases that flow downstream to the turbine. The turbine
is driven by the exhaust gases and mechanically powers the
compressor and fan via one or more central rotating shafts. Energy
from the combustion gases not used by the turbine is discharged
through an exhaust nozzle, producing thrust to power the
aircraft.
[0004] Turbofan gas turbine engines contain an engine core and fan
surrounded by a fan case, forming part of a nacelle. The nacelle is
a housing that contains the engine. The fan is positioned forward
of the engine core and within the fan case. The engine core is
surrounded by an engine core cowl and the area between the nacelle
and the engine core cowl is functionally defined as a fan duct. The
fan duct is substantially annular in shape to accommodate the
airflow from the fan and around the engine core cowl. The airflow
through the fan duct, known as bypass air, travels the length of
the fan duct and exits at the aft end of the fan duct at an exhaust
nozzle.
[0005] In addition to thrust generated by combustion gasses, the
fan of gas turbine engines also produces thrust by accelerating and
discharging ambient air through the exhaust nozzle. Various parts
of the gas turbine engine generate heat while operating, including
the compressor, combustor, turbine, central rotating shaft and fan.
To maintain proper operational temperatures, excess heat is often
removed from the engine via oil coolant loops, including air/oil or
fuel/oil heat exchangers, and dumped into the bypass airflow for
removal from the system.
[0006] Gas turbine engines require a supply of lubricant, such as
oil, to mechanical components such as, but not limited to,
bearings, seals, and the like. The oil can be used as a lubricant,
a coolant or both. Typical oil systems supply the oil to a
manifold, which then directs the oil to various engine components.
The lubricant may be filtered to remove unwanted debris, and may
also be de-aerated to remove any air absorbed by the oil while
lubricating and cooling the components. An oil cooler may remove
heat gained from the lubricated components.
[0007] In prior art oil systems, the quantity of oil pumped to the
components is typically based on speed or load conditions. However,
either approach may result in an oversupply of oil in low load
conditions, such as during cruise or taxiing, for example. This
reduces the efficiency of the engine in that the excess oil is
pumped through the engine. Additionally, the lubricant then needs
to be cooled before being used again, increasing the demands on the
coolers and further reducing efficiency. In light of the foregoing,
it can be seen that an oil system is needed that can provide oil in
the quantity required according to a range of conditions being
experienced by the engine.
[0008] Accordingly, there is a need for an improved lubrication
schedule for a gas turbine engine.
SUMMARY OF THE INVENTION
[0009] To meet the needs described above and others, the present
disclosure provides a lubrication system for a gas turbine engine,
that may include a pump for moving a lubricant, a lubricant tank
for storing the lubricant, an engine component requiring
lubrication from the lubricant, a conduit between the lubricant
tank and the engine component, and a scheduling valve positioned in
the conduit between the lubricant tank and the engine component,
the flow scheduling valve varying a flow of the lubricant to the
engine component based on a condition.
[0010] The engine component may be a fan drive gear system, and the
scheduling valve may be controlled by a controller. Additionally,
the controller may include a memory and a processor, and the memory
may include an engine performance model. The condition may be a
calculated engine torque, an engine startup, cruising, an altitude
of the gas turbine engine, a vibration level of the gas turbine
engine, or a weight on wheels.
[0011] The present disclosure also provides a gas turbine engine,
that may include a compressor, a combustor downstream of the
compressor, a lubrication system including a pump for moving a
lubricant, a lubricant tank for storing the lubricant, an engine
component requiring lubrication from the lubricant, a conduit
between the lubricant tank and the engine component, a scheduling
valve positioned in the conduit between the lubricant tank and the
engine component, the flow scheduling valve varying a flow of the
lubricant to the engine component based on a condition, and a
turbine downstream of the combustor.
[0012] The engine component may be a fan drive gear system, and the
scheduling valve may be controlled by a controller. Further, the
controller may include a memory and a processor, and the memory may
include an engine performance model. The condition may be a
calculated engine torque, an altitude of the gas turbine engine or
a vibration level of the gas turbine engine.
[0013] The present disclosure further provides a method of
lubricating an engine component of a gas turbine engine that may
include pumping a lubricant from a lubricant tank through a conduit
to the engine component using a pump, determining a condition
experienced by the gas turbine engine, and regulating a flow of the
lubricant to the engine component with a scheduling valve, the
regulation of the flow of lubricant based upon the condition
experienced by the gas turbine engine.
[0014] The engine component may be a fan drive gear system, and the
scheduling valve may be controlled by a controller, wherein the
controller may include a memory and a processor, and the memory may
include an engine performance model.
[0015] These, and other aspects and features of the present
disclosure, will be better understood upon reading the following
detailed description when taken in conjunction with the
accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0016] For further understanding of the disclosed concepts and
embodiments, reference may be made to the following detailed
description, read in connection with the drawings, wherein like
elements are numbered alike, and in which:
[0017] FIG. 1 is a sectional view of a gas turbine engine
constructed in accordance with an embodiment.
[0018] FIG. 2 is a schematic representation of a lubrication
injection system constructed in accordance with an embodiment.
[0019] FIG. 3 is a schematic representation of a controller and
associated engine conditions the controller may monitor according
to an embodiment.
[0020] FIG. 4 is a flowchart depicting a sample sequence of actions
and events which may be practiced in accordance with an
embodiment.
[0021] It is to be noted that the appended drawings illustrate only
exemplary embodiments and are therefore not to be considered
limiting with respect to the scope of the disclosure or claims.
Rather, the concepts of the present disclosure may apply within
other equally effective embodiments. Moreover, the drawings are not
necessarily to scale, emphasis generally being placed upon
illustrating the principles of certain embodiments.
DETAILED DESCRIPTION
[0022] Referring now to the drawings, and with specific reference
to FIG. 1, a gas turbine engine 20 is generally referred to by
reference numeral 20. The gas turbine engine 20 is disclosed herein
as a two-spool turbofan that generally incorporates a fan section
22, a compressor section 24, a combustor section 26 and a turbine
section 28. Alternative engines might include an augmentor section
(not shown) among other systems or features. The fan section 22
drives air along a bypass flow path B in a bypass duct defined
within a nacelle 15, while the compressor section 24 drives air
along a core flow path C for compression and communication into the
combustor section 26 then expansion through the turbine section 28.
Although depicted as a two-spool turbofan gas turbine engine in the
disclosed non-limiting embodiment, it should be understood that the
concepts described herein are not limited to use with two-spool
turbofans as the teachings may be applied to other types of turbine
engines including three-spool architectures.
[0023] The exemplary engine 20 generally includes a low speed spool
30 and a high speed spool 32 mounted for rotation about an engine
central longitudinal axis A relative to an engine static structure
36 via several bearing systems 38. It should be understood that
various bearing systems 38 at various locations may alternatively
or additionally be provided, and the location of bearing systems 38
may be varied as appropriate to the application.
[0024] The low speed spool 30 generally includes an inner shaft 40
that interconnects a fan 42, a low pressure compressor 44 and a low
pressure turbine 46. The inner shaft 40 is connected to the fan 42
through a speed change mechanism, which in exemplary gas turbine
engine 20 is illustrated as a geared architecture 48 to drive the
fan 42 at a lower speed than the low speed spool 30. The high speed
spool 32 includes an outer shaft 50 that interconnects a high
pressure compressor 52 and high pressure turbine 54. A combustor 56
is arranged in exemplary gas turbine 20 between the high pressure
compressor 52 and the high pressure turbine 54. A mid-turbine frame
57 of the engine static structure 36 is arranged generally between
the high pressure turbine 54 and the low pressure turbine 46. The
mid-turbine frame 57 further supports bearing systems 38 in the
turbine section 28. The inner shaft 40 and the outer shaft 50 are
concentric and rotate via bearing systems 38 about the engine
central longitudinal axis A which is collinear with their
longitudinal axes.
[0025] The core airflow is compressed by the low pressure
compressor 44 then the high pressure compressor 52, mixed and
burned with fuel in the combustor 56, then expanded over the high
pressure turbine 54 and low pressure turbine 46. The mid-turbine
frame 57 includes airfoils 59 which are in the core airflow path C.
The turbines 46, 54 rotationally drive the respective low speed
spool 30 and high speed spool 32 in response to the expansion. It
will be appreciated that each of the positions of the fan section
22, compressor section 24, combustor section 26, turbine section
28, and geared architecture 48 may be varied. For example, geared
architecture 48 may be located aft of combustor section 26 or even
aft of turbine section 28, and fan section 22 may be positioned
forward or aft of the location of geared architecture 48.
[0026] The gas turbine engine 20 in one example is a high-bypass
geared aircraft engine. In a further example, the gas turbine
engine 20 bypass ratio is greater than about six (6), with an
example embodiment being greater than about ten (10), the geared
architecture 48 is an epicyclic gear train, such as a planetary
gear system or other gear system, with a gear reduction ratio of
greater than about 2.3 and the low pressure turbine 46 has a
pressure ratio that is greater than about five. In one disclosed
embodiment, the gas turbine engine 20 bypass ratio is greater than
about ten (10:1), the fan diameter is significantly larger than
that of the low pressure compressor 44, and the low pressure
turbine 46 has a pressure ratio that is greater than about five
5:1. Low pressure turbine 46 pressure ratio is pressure measured
prior to inlet of low pressure turbine 46 as related to the
pressure at the outlet of the low pressure turbine 46 prior to an
exhaust nozzle. The geared architecture 48 may be an epicycle gear
train, such as a planetary gear system or other gear system, with a
gear reduction ratio of greater than about 2.3:1. It should be
understood, however, that the above parameters are only exemplary
of one embodiment of a geared architecture engine and that the
present invention is applicable to other gas turbine engines
including direct drive turbofans.
[0027] A significant amount of thrust is provided by the bypass
flow B due to the high bypass ratio. The fan section 22 of the gas
turbine engine 20 is designed for a particular flight
condition--typically cruise at about 0.8 Mach and about 35,000
feet. The flight condition of 0.8 Mach and 35,000 ft, with the
engine at its best fuel consumption--also known as "bucket cruise
Thrust Specific Fuel Consumption (`TSFC`)"--is the industry
standard parameter of lbm of fuel being burned divided by lbf of
thrust the engine produces at that minimum point. "Low fan pressure
ratio" is the pressure ratio across the fan blade alone, without a
Fan Exit Guide Vane ("FEGV") system. The low fan pressure ratio as
disclosed herein according to one non-limiting embodiment is less
than about "Low corrected fan tip speed" is the actual fan tip
speed in ft/sec divided by an industry standard temperature
correction of [(Tram.degree. R) I (518.7.degree. R)].sup.0.5. The
"Low corrected fan tip speed" as disclosed herein according to one
non-limiting embodiment is less than about 1150 ft/second.
[0028] A lubrication system 70 may be used to supply a lubricant 74
to an engine component 78 as shown in FIG. 2. The lubricant 74 may
serve to lubricate, cool or supply another substance to various
parts of the gas turbine engine 20. In one embodiment, the engine
component 78 may be a fan drive gear system 80, which may be
defined as an apparatus that allows the fan 42 to rotate at a
different angular speed from the low speed spool 30.
[0029] In operation, components of the gas turbine engine 20 may
require lubrication or cooling. The lubrication system 70 may
include a lubricant tank 82, or sump, for storing the lubricant 74
when not being used. The lubrication system 70 may also include a
pump 86 for drawing a supply of lubricant 74 from the lubricant
tank 82 through a conduit 90. The conduit 90 may travel between the
lubricant tank 82 and a scheduling valve 94, and between other gas
turbine engine 20 components. The pump 86 may be driven by a
rotating component of the gas turbine engine 20, or by other means.
The pump 86 may further supply a constant or varying flow of
lubricant 74 to the scheduling valve 94.
[0030] Upon reaching the scheduling valve 94, the lubricant 74 may
be wholly or partially diverted to one of multiple areas by the
scheduling valve 94. In one scenario, the lubricant 74 may be sent
to an engine component 78 for use. In another scenario, the
lubricant 74 may be sent to a second engine component 98 for use.
In a third scenario, the lubricant 74 may be sent back to the
lubricant tank 82. In a fourth scenario, the lubricant 74 may be
sent to any two or three of the engine component 78, second engine
component 98 and lubricant tank 82. Further, although not shown,
the lubricant 74 may also be sent to additional parts of the gas
turbine engine 20. Following lubricant 74 use in gas turbine engine
20 components, the lubricant may travel back to the lubricant tank
82.
[0031] During its use, the lubricant 74 may acquire adverse
properties while being pumped and used throughout the lubrication
system 70, including becoming aerated, accumulating debris and
absorbing heat. To address these properties, the lubrication system
70 may include, respectively, a de-aerator 102, a filter 106 and a
cooler 110. These three elements 102, 106, 110 may be located at
various points within the lubrication system 70. Further, although
shown with one of each of the elements, the lubrication system 70
may include more than one of any of them.
[0032] While in operation, gas turbine engine 20 components need a
degree of lubricant 74 flow for proper functionality. This flow
amount may vary according to different demands and situations.
However, pumping and receiving more than a certain required degree
of lubricant 74 can needlessly affect overall gas turbine engine 20
efficiency, as more lubricant 74 than necessary is pumped, cooled,
de-aerated and filtered.
[0033] In order to provide gas turbine engine 20 components with
adequate lubrication, the scheduling valve 94 may regulate a flow
of lubricant 74 to an engine component 78, second engine component
98 or lubricant tank 82, as described above. The scheduling valve
94 may regulate such flows in response to a condition experienced
by the gas turbine engine 20. Additionally, the scheduling valve 94
may regulate such lubricant flows in response to more than one
condition experienced by the gas turbine engine 20. A condition may
be indicated by a sensor, calculation, operator input or stored
information, and may serve to provide data about the current, past
or future state of the gas turbine engine 20.
[0034] The gas turbine engine 20 may include a controller 114,
which may further incorporate a processor 118 and a memory 122. The
memory 122 may include an engine performance model 126.
Additionally, the controller 114 may also be a Full Authority
Digital Engine Control, or FADEC. The engine performance model 126
may include a series of stored algorithms able to input a condition
and, after analysis by the stored algorithms, signal the controller
114 to output a command to a component of the gas turbine engine
20, such as the scheduling valve 94. In this manner, one or more
conditions can be detected and responded to by commanding a
response from a component or system of the gas turbine engine
20.
[0035] The controller 114 may also receive feedback from the
scheduling valve 94 indicating the position of the scheduling valve
94. Such feedback may be used by the controller 114 to verify the
position of the scheduling valve 94, or to calculate a future
scheduling valve 94 movement.
[0036] The engine performance model 126 can respond to a range of
conditions, as shown in FIG. 3. In a first example, an RPM sensor
130, a fuel flow sensor 134 and an altitude sensor 138 can be used
to gather data and provide a calculated torque condition for the
fan 42, low speed spool 30, engine component 78 or fan drive gear
system 80. Such a calculated torque condition can be provided to
the engine performance model 126, which can then signal the
controller 114 to output a command to the scheduling valve 94. The
engine performance model 126 may include stored relationship values
between a calculated torque condition and a scheduling valve 94
position to provide a desired flow rate of lubricant 74 to one or
more components of the gas turbine engine 20. In this manner, a
calculated torque condition can determine a scheduling valve 124
position, and thus a lubricant 74 flow rate, to an engine component
78.
[0037] By the same process, the RPM sensor 130, fuel flow sensor
134 and altitude sensor 138 can be used to gather data and provide
a cruise condition for the fan 42, low speed spool 30, engine
component 78 or fan drive gear system 80. Cruise condition may be
defined as operation below a maximum level, and sustained within a
relatively narrow range of operation. Such a cruise condition can
be provided to the engine performance model 126, which can then
signal the controller 114 to output a command to the scheduling
valve 94. The engine performance model 126 may include stored
relationship values between a cruise condition and a scheduling
valve 94 position to provide a desired flow rate of lubricant 74 to
one or more components of the gas turbine engine 20. In this
manner, a cruise condition can determine a scheduling valve 124
position, and thus a lubricant 74 flow rate, to an engine component
78.
[0038] Similarly, a burner pressure sensor 142 can be used to
gather burner data for the engine performance model 126, which can
then signal the controller 114 to output a command to the
scheduling valve 94. The burner pressure sensor 142 may sense a
pressure of a flow, region or process within the combustor 26. The
engine performance model 126 may include stored relationship values
between a burner pressure condition and a scheduling valve 94
position to provide a desired flow rate of lubricant 74 to one or
more components of the gas turbine engine 20.
[0039] Additionally, a startup sensor 146 can be used to gather
data indicating a startup condition for the engine performance
model 126, which can then signal the controller 114 to output a
command to the scheduling valve 94. Startup may be defined as a
process during which the gas turbine engine 20 transitions from a
non-operating state to an operating state. The engine performance
model 126 may include stored relationship values between a startup
condition and a scheduling valve 94 position to provide a desired
flow rate of lubricant 74 to one or more components of the gas
turbine engine 20.
[0040] Further, an altitude sensor 150 can be used to gather data
indicating an altitude of the gas turbine engine 20 for the engine
performance model 126, which can then signal the controller 114 to
output a command to the scheduling valve 94. The engine performance
model 126 may include stored relationship values between an
altitude condition and a scheduling valve 94 position to provide a
desired flow rate of lubricant 74 to one or more components of the
gas turbine engine 20.
[0041] A weight on wheels sensor 154 can be used to gather data
indicating a degree of weight on wheels for the engine performance
model 126, which can then signal the controller 114 to output a
command to the scheduling valve 94. Weight on wheels may occur when
the weight of an aircraft, on which the gas turbine engine 20 is
mounted, is supported by the aircraft's wheels. The engine
performance model 126 may include stored relationship values
between a weight on wheels condition and a scheduling valve 94
position to provide a desired flow rate of lubricant 74 to one or
more components of the gas turbine engine 20.
[0042] Further, a vibration sensor 158 can be used to gather data
indicating a vibration level for the engine performance model 126,
which can then signal the controller 114 to output a command to the
scheduling valve 94. The vibration sensor 158 may be an
accelerometer, and may be located at various positions within or on
the gas turbine engine 20, including, but not limited to the
nacelle 15, compressor 24, turbine 28, combustor 26, engine
component 78, fan drive gear system 80, fan 42 or low or high speed
spool 30, 32. The engine performance model 126 may include stored
relationship values between a vibration condition and a scheduling
valve 94 position to provide a desired flow rate of lubricant 74 to
one or more components of the gas turbine engine 20.
[0043] The present disclosure allows for the successful lubrication
and cooling of various gas turbine engine 20 components. Further,
the disclosed lubrication system 70 may increase overall gas
turbine engine 20 efficiency, as a regulated flow of lubricant 74
to the engine component 78 reduces mechanical losses, and eases the
burden on de aerators 102, filters 106 and coolers 110. In turn,
this reduction may lead to decreased build, acquisition and
maintenance costs, reduced system weight and improved system
packaging.
[0044] The present disclosure not only sets forth a lubrication
system 70, but a method of lubricating an engine component of a gas
turbine engine as well. For example, such a method in operation can
be understood by referencing the flowchart in FIG. 4. The method
may comprise pumping a lubricant from a lubricant tank through a
conduit to the engine component using a pump, as shown in box 400,
and determining a condition experienced by the gas turbine engine,
as shown in box 404. Further, the method may include regulating a
flow of the lubricant to the engine component with a scheduling
valve, the regulation of the flow of lubricant based upon the
condition experienced by the gas turbine engine, as shown in box
408.
[0045] While the present disclosure has shown and described details
of exemplary embodiments, it will be understood by one skilled in
the art that various changes in detail may be effected therein
without departing from the spirit and scope of the disclosure as
defined by claims supported by the written description and
drawings. Further, where these exemplary embodiments (and other
related derivations) are described with reference to a certain
number of elements it will be understood that other exemplary
embodiments may be practiced utilizing either less than or more
than the certain number of elements.
[0046] In operation, the present disclosure sets forth a
lubrication system for a gas turbine engine which can find
industrial applicability in a variety of settings. For example, the
disclosure may be advantageously employed by gas turbine engines in
aviation, naval and industrial settings. More specifically, the
lubrication system for a gas turbine engine can be used to
successfully lubricate and cool gas turbine engine components,
while refraining from over-lubricating the components in response
to various conditions experienced by the gas turbine engine.
[0047] The present disclosure allows for the successful lubrication
and cooling of various gas turbine engine components. Further, the
disclosed lubrication system may increase overall gas turbine
engine efficiency, as a regulated flow of lubricant to the engine
component reduces mechanical losses, and eases the burden on
de-aerators, filters and coolers. In turn, this reduction may lead
to decreased build, acquisition and maintenance costs, reduced
system weight and improved system packaging.
[0048] The lubrication system of the present disclosure contributes
to the continued and efficient operation of a gas turbine engine.
The disclosed system may be original equipment on new gas turbine
engines, or added as a retrofit to existing gas turbine
engines.
* * * * *