U.S. patent application number 16/539778 was filed with the patent office on 2021-02-18 for transmission shift control method for reduced torque transients.
The applicant listed for this patent is Hamilton Sundstrand Corporation. Invention is credited to Stephen Michael Bortoli, Jonathan C. Dell, Aaron M. Finke.
Application Number | 20210047938 16/539778 |
Document ID | / |
Family ID | 1000005370936 |
Filed Date | 2021-02-18 |
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United States Patent
Application |
20210047938 |
Kind Code |
A1 |
Finke; Aaron M. ; et
al. |
February 18, 2021 |
TRANSMISSION SHIFT CONTROL METHOD FOR REDUCED TORQUE TRANSIENTS
Abstract
A power extraction system is provided and includes a
low-pressure spool of a gas turbine engine, the low-pressure spool
being rotatable at an input rotational speed between a first
minimum speed and a first maximum speed, downstream components
rotatable at an output rotational speed between a second minimum
speed and a second maximum speed and a transmission assembly by
which rotations of the low-pressure spool at the input rotational
speed are transmittable at the output rotational speed to the
downstream components. The transmission assembly includes clutches
and a controller configured to control openings and closings of the
clutches according to an upshifting algorithm whereby a torque
applied by the downstream components is used to reduce the output
rotational speed to an output speed of a gear into which the
transmission assembly is shifting.
Inventors: |
Finke; Aaron M.;
(Janesville, WI) ; Bortoli; Stephen Michael;
(Roscoe, IL) ; Dell; Jonathan C.; (Elgin,
IL) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Hamilton Sundstrand Corporation |
Charlotte |
NC |
US |
|
|
Family ID: |
1000005370936 |
Appl. No.: |
16/539778 |
Filed: |
August 13, 2019 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
F16H 3/02 20130101; F16H
2200/00 20130101; F05D 2220/3217 20130101; H02P 2101/25 20150115;
F16D 21/00 20130101; H02P 9/06 20130101; F05D 2220/74 20130101;
F01D 15/10 20130101; F02C 7/32 20130101 |
International
Class: |
F01D 15/10 20060101
F01D015/10; F16H 3/02 20060101 F16H003/02; F16D 21/00 20060101
F16D021/00; F02C 7/32 20060101 F02C007/32; H02P 9/06 20060101
H02P009/06 |
Claims
1. A power extraction system, comprising: a low-pressure spool of a
gas turbine engine, the low-pressure spool being rotatable at an
input rotational speed between a first minimum speed and a first
maximum speed; downstream components rotatable at an output
rotational speed between a second minimum speed and a second
maximum speed; and a transmission assembly by which rotations of
the low-pressure spool at the input rotational speed are
transmittable at the output rotational speed to the downstream
components, the transmission assembly comprising first and second
clutches and a controller configured to control openings and
closings of the clutches according to an upshifting algorithm
whereby a torque applied by the downstream components is used to
reduce the output rotational speed to an output speed of a gear
into which the transmission assembly is shifting by: closing the
first clutch in a first gear during a first ramping-up of the input
rotational speed, opening the first clutch at a first predefined
output rotational speed, using the torque applied by the downstream
components to reduce the output rotational speed to the output
speed of a second gear, closing the second clutch in the second
gear when the output rotational speed reaches the output speed of
the second gear and during a second ramping-up of the input
rotational speed, opening the second clutch at a second predefined
output rotational speed and using the torque applied by the
downstream components to reduce the output rotational speed to the
output speed of a third gear.
2. The power extraction system according to claim 1, wherein the
gas turbine engine comprises: a high-pressure spool, which is
rotatable by relatively high-pressure and high-temperature fluids;
and the low-pressure spool, which is rotatable by relatively
low-pressure and low-temperature fluids.
3. The power extraction system according to claim 1, wherein the
downstream components comprise a generator and the torque applied
by the downstream components comprises drag torque.
4. The power extraction system according to claim 1, wherein the
second minimum speed is greater than the first minimum speed.
5. The power extraction system according to claim 1, wherein the
first minimum speed is between 2,000 and 4,000 rpm, the first
maximum speed is greater than 18,000 rpm, the second minimum speed
is between 6,000 and 8,000 rpm and the second maximum speed is
about 16,000 rpm.
6. The power extraction system according to claim 1, wherein: the
transmission assembly comprises an input shaft coupled to the
low-pressure spool and an output shaft coupled to the downstream
components, and input torque is transmitted from the input shaft to
the output shaft via the clutches.
7. The power extraction system according to claim 6, wherein: the
transmission assembly further comprises sensors operably disposed
to sense rotational speeds of the input and output shafts.
8. The power extraction system according to claim 1, wherein the
output rotational speed is reduced to the output speed of the gear
into which the transmission assembly is shifting at one of a
substantially constant input rotational speed and a variable input
rotational speed.
9. A transmission assembly of a power extraction system, the
transmission assembly comprising: an input shaft coupled to a
low-pressure spool of a gas turbine engine whereby rotations of the
low-pressure spool between first minimum and maximum speeds drive
input shaft rotations at an input rotational speed; an output shaft
coupled to downstream components whereby output shaft rotations at
an output rotational speed drive rotations of the downstream
components between second minimum and maximum speeds; clutches by
which the input shaft rotations at the input rotational speed drive
output shaft rotations at the output rotational speed; and a
controller configured to control openings and closings of the
clutches according to an upshifting algorithm whereby a torque
applied by the downstream components is used to reduce the output
rotational speed to an output speed of a gear into which the
transmission assembly is shifting by: closing a first one of the
clutches in a first gear during a first ramping-up of the input
rotational speed, opening the first one of the clutches at a first
predefined output rotational speed, using the torque applied by the
downstream components to reduce the output rotational speed to the
output speed of a second gear, closing a second one of the clutches
in the second gear when the output rotational speed reaches the
output speed of the second gear and during a second ramping-up of
the input rotational speed, opening the second one of the clutches
at a second predefined output rotational speed and using the torque
applied by the downstream components to reduce the output
rotational speed to the output speed of a third gear.
10. The transmission assembly according to claim 9, wherein the gas
turbine engine comprises: a high-pressure spool, which is rotatable
by relatively high-pressure and high-temperature fluids; and the
low-pressure spool, which is rotatable by relatively low-pressure
and low-temperature fluids.
11. The transmission assembly according to claim 9, wherein the
downstream components comprise a generator and the torque applied
by the downstream components comprises drag torque.
12. The transmission assembly according to claim 9, wherein the
second minimum speed is greater than the first minimum speed.
13. The transmission assembly according to claim 9, wherein the
first minimum speed is between 2,000 and 4,000 rpm, the first
maximum speed is greater than 18,000 rpm, the second minimum speed
is between 6,000 and 8,000 rpm and the second maximum speed is
about 16,000 rpm.
14. The transmission assembly according to claim 9, wherein:
sensors are operably disposed to sense rotational speeds of the
input and output shafts.
15. The transmission assembly according to claim 9, wherein the
output rotational speed is reduced to the output speed of the gear
into which the transmission assembly is shifting at one of a
substantially constant input rotational speed and a variable input
rotational speed.
16. A method of operating a power extraction system, comprising: a
low-pressure spool of a gas turbine engine, the low-pressure spool
being rotatable at an input rotational speed between first minimum
and maximum speeds; downstream components rotatable at an output
rotational speed between second minimum and maximum speeds; and a
transmission assembly comprising clutches by which rotations of the
low-pressure spool at the input rotational speed are transmittable
at the output rotational speed to the downstream components, the
method comprising controlling openings and closings of the clutches
according to an upshifting algorithm whereby a torque applied by
the downstream components is used to reduce the output rotational
speed to an output speed of a gear into which the transmission
assembly is shifting, wherein the controlling comprises closing a
first one of the clutches in a first gear during a first ramping-up
of the input rotational speed, opening the first one of the
clutches at a first predefined output rotational speed, using the
torque applied by the downstream components to reduce the output
rotational speed to the output speed of a second gear, closing a
second one of the clutches in the second gear when the output
rotational speed reaches the output speed of the second gear and
during a second ramping-up of the input rotational speed, opening
the second one of the clutches at a second predefined output
rotational speed and using the torque applied by the downstream
components to reduce the output rotational speed to the output
speed of a third gear.
17. The method according to claim 16, further comprising sensing
the input and output rotational speeds, wherein the controlling is
executed in accordance with the sensing.
18. (canceled)
19. The method according to claim 16, further comprising repeating
a sequence of opening and closing the first and second ones of the
clutches.
20. The method according to claim 16, further comprising using the
torque applied by the downstream components to reduce the output
rotational speed to the output speed of the gear into which the
transmission assembly is shifting at one of a substantially
constant input rotational speed and a variable input rotational
speed.
Description
BACKGROUND
[0001] The following description relates to transmissions and, more
specifically, to a method of transmission shift control for reduced
torque transients.
[0002] Modern engines are often configured as gas turbine engines
in which combustible materials are combusted and the products of
the combustion are directed into a turbine. Within the turbine, the
products of the combustion are expanded whereupon the expanded
products of combustion drive rotation of rotors. This occurs in a
high-pressure spool (HS), which is associated with regions in which
the products of combustion have relatively high pressures and high
temperatures, and in a low-pressure spool (LS), which is associated
with regions in which the products of combustion have relatively
low pressures and low temperatures.
[0003] Recently, engine manufacturers have been attempting to
transfer accessory power extraction from the HS to the LS. Doing so
can be problematic, however, since a typical LS speed range (up to
10:1) does not necessarily align with a typical accessory speed
range (.about.2.2:1). This issue has been addressed previously by
the use of multi-speed shifting transmissions to condition LS
output speeds but, in these cases, transmission shifts caused
sudden speed changes to downstream components (i.e., generators).
These sudden speed changes resulted in torque transients to the
driveline components which, in turn, led to undesirable
consequences including increased stress and wear, reduced life and
dynamic responses.
BRIEF DESCRIPTION
[0004] According to an aspect of the disclosure, a power extraction
system is provided and includes a low-pressure spool of a gas
turbine engine, the low-pressure spool being rotatable at an input
rotational speed between a first minimum speed and a first maximum
speed, downstream components rotatable at an output rotational
speed between a second minimum speed and a second maximum speed and
a transmission assembly by which rotations of the low-pressure
spool at the input rotational speed are transmittable at the output
rotational speed to the downstream components. The transmission
assembly includes clutches and a controller configured to control
openings and closings of the clutches according to an upshifting
algorithm whereby a torque applied by the downstream components is
used to reduce the output rotational speed to an output speed of a
gear into which the transmission assembly is shifting.
[0005] In accordance with additional or alternative embodiments,
the gas turbine engine includes a high-pressure spool, which is
rotatable by relatively high-pressure and high-temperature fluids,
and the low-pressure spool, which is rotatable by relatively
low-pressure and low-temperature fluids.
[0006] In accordance with additional or alternative embodiments,
the downstream components include a generator and the torque
applied by the downstream components includes drag torque.
[0007] In accordance with additional or alternative embodiments,
the second minimum speed is greater than the first minimum
speed.
[0008] In accordance with additional or alternative embodiments,
the first minimum speed is between 2,000 and 4,000 rpm, the first
maximum speed is greater than 18,000 rpm, the second minimum speed
is between 6,000 and 8,000 rpm and the second maximum speed is
about 16,000 rpm.
[0009] In accordance with additional or alternative embodiments,
the transmission assembly includes an input shaft coupled to the
low-pressure spool and an output shaft coupled to the downstream
components and input torque is transmitted from the input shaft to
the output shaft via the clutches.
[0010] In accordance with additional or alternative embodiments,
the transmission assembly further includes sensors operably
disposed to sense rotational speeds of the input and output shafts
and the clutches include a first clutch and a second clutch which
are controlled by the controller to open and close in an
alternating sequence in accordance with readings of the
sensors.
[0011] In accordance with additional or alternative embodiments,
the output rotational speed is reduced to the output speed of the
gear into which the transmission assembly is shifting at one of a
substantially constant input rotational speed and a variable input
rotational speed.
[0012] According to an aspect of the disclosure, a transmission
assembly of a power extraction system is provided. The transmission
assembly includes an input shaft coupled to a low-pressure spool of
a gas turbine engine whereby rotations of the low-pressure spool
between first minimum and maximum speeds drive input shaft
rotations at an input rotational speed, an output shaft coupled to
downstream components whereby output shaft rotations at an output
rotational speed drive rotations of the downstream components
between second minimum and maximum speeds, clutches by which the
input shaft rotations at the input rotational speed drive output
shaft rotations at the output rotational speed and a controller.
The controller is configured to control openings and closings of
the clutches according to an upshifting algorithm whereby a torque
applied by the downstream components is used to reduce the output
rotational speed to an output speed of a gear into which the
transmission assembly is shifting.
[0013] In accordance with additional or alternative embodiments,
the gas turbine engine includes a high-pressure spool, which is
rotatable by relatively high-pressure and high-temperature fluids,
and the low-pressure spool, which is rotatable by relatively
low-pressure and low-temperature fluids.
[0014] In accordance with additional or alternative embodiments,
the downstream components include a generator and the torque
applied by the downstream components comprises drag torque.
[0015] In accordance with additional or alternative embodiments,
the second minimum speed is greater than the first minimum
speed.
[0016] In accordance with additional or alternative embodiments,
the first minimum speed is between 2,000 and 4,000 rpm, the first
maximum speed is greater than 18,000 rpm, the second minimum speed
is between 6,000 and 8,000 rpm and the second maximum speed is
about 16,000 rpm.
[0017] In accordance with additional or alternative embodiments,
sensors are operably disposed to sense rotational speeds of the
input and output shafts and the clutches include a first clutch and
a second clutch which are controlled by the controller to open and
close in an alternating sequence in accordance with readings of the
sensors.
[0018] In accordance with additional or alternative embodiments,
the output rotational speed is reduced to the output speed of the
gear into which the transmission assembly is shifting at one of a
substantially constant input rotational speed and a variable input
rotational speed.
[0019] According to another aspect of the disclosure, a method of
operating a power extraction system is provided. The power
extraction system includes a low-pressure spool of a gas turbine
engine, the low-pressure spool being rotatable at an input
rotational speed between first minimum and maximum speeds,
downstream components rotatable at an output rotational speed
between second minimum and maximum speeds and a transmission
assembly including clutches by which rotations of the low-pressure
spool at the input rotational speed are transmittable at the output
rotational speed to the downstream components. The method includes
controlling openings and closings of the clutches according to an
upshifting algorithm whereby a torque applied by the downstream
components is used to reduce the output rotational speed to an
output speed of a gear into which the transmission assembly is
shifting.
[0020] In accordance with additional or alternative embodiments,
the method further includes sensing the input and output rotational
speeds and that the controlling is executed in accordance with the
sensing.
[0021] In accordance with additional or alternative embodiments,
the controlling includes closing a first one of the clutches in a
first gear during a first ramping-up of the input rotational speed,
opening the first one of the clutches at a first predefined output
rotational speed, using the torque applied by the downstream
components to reduce the output rotational speed to the output
speed of a second gear, closing a second one of the clutches in the
second gear when the output rotational speed reaches the output
speed of the second gear and during a second ramping-up of the
input rotational speed, opening the second one of the clutches at a
second predefined output rotational speed and using the torque
applied by the downstream components to reduce the output
rotational speed to the output speed of a third gear.
[0022] In accordance with additional or alternative embodiments,
the method further includes repeating a sequence of opening and
closing the first and second ones of the clutches.
[0023] In accordance with additional or alternative embodiments,
the method further includes using the torque applied by the
downstream components to reduce the output rotational speed to the
output speed of the gear into which the transmission assembly is
shifting at one of a substantially constant input rotational speed
and a variable input rotational speed.
[0024] These and other advantages and features will become more
apparent from the following description taken in conjunction with
the drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0025] The subject matter, which is regarded as the disclosure, is
particularly pointed out and distinctly claimed in the claims at
the conclusion of the specification. The foregoing and other
features and advantages of the disclosure are apparent from the
following detailed description taken in conjunction with the
accompanying drawings in which:
[0026] FIG. 1 is a schematic diagram of a transmission system in
accordance with embodiments; and
[0027] FIG. 2 is a graphical depiction of a transmission control
method for reduced torque transients in accordance with
embodiments.
[0028] These and other advantages and features will become more
apparent from the following description taken in conjunction with
the drawings.
DETAILED DESCRIPTION
[0029] As will be described below, an upshifting methodology is
provided where, instead of opening a first clutch pack while
closing a second clutch pack (which would result in a torque
transient due to the sudden speed change), a drag torque of a
generator and/or other engine accessories is used to reduce an
output speed of the transmission until the output speed matches the
output speed of the gear that the transmission will shift into.
Speed sensors on the transmission input and output are used in
conjunction with algorithms to determine when to close the second
clutch pack.
[0030] With reference to FIG. 1, a power extraction system 101 is
provided and includes a gas turbine engine 110. The gas turbine
engine 110 includes a compressor 111, which compresses inlet air, a
combustor 112 in which the compressed inlet air is mixed with fuel
and combusted to produce fluids in the form of products of the
combustion and a turbine 113. Within the turbine 113, the fluids
are expanded to drive rotations of a rotor 114. The rotations of
the rotor 114 drives operations of the compressor 111. The rotor
114 can have a high-pressure spool (HS) 115 and a low-pressure
spool (LS) 116. The HS 115 is rotatably driven in portions of the
turbine 113 associated with an expansion of relatively
high-pressure and high-temperature fluids and the LS 116 is
rotatably driven in portions of the turbine 113 associated with an
expansion of relatively low-pressure and low-temperature fluids.
The LS 116 is thus rotatable at an input rotational speed defined
inclusively between a first minimum speed and a first maximum
speed.
[0031] The power extraction system 101 further includes downstream
components 120 and a transmission assembly 130. The downstream
components 120 are rotatable at an output rotational speed between
a second minimum speed and a second maximum speed. The downstream
components 120 can be provided, for example, as a generator 121.
The generator 121 can be configured to generate electricity and can
be coupled to an electrical load 122 that is receptive of and
operated by the generated electricity. The electrical load 122 thus
exerts or applies a torque (i.e., a drag torque) on the generator
121. The transmission assembly 130 is disposed and configured such
that rotations of the LS 116 at the input rotational speed are
transmittable at the output rotational speed to the downstream
components 120.
[0032] With reference to FIG. 2 and, in accordance with
embodiments, a range of the input rotational speed is about 8:1
between the first maximum speed and the first minimum speed whereas
a range of the output rotational speed is about .about.2.2:1
between the second maximum speed and the second minimum speed. As
such, the second minimum speed can be, but is not required to be,
greater than the first minimum speed and the second maximum speed
can be, but is not required to be, less than the first maximum
speed. In accordance with further embodiments, the first minimum
speed can be between 2,000 and 4,000 rpm, the first maximum speed
can be greater than 18,000 rpm, the second minimum speed can be
between 6,000 and 8,000 rpm and the second maximum speed can be
about 16,000 rpm.
[0033] With reference back to FIG. 1, the transmission assembly 130
includes an input shaft 131, an output shaft 132, clutches 133,
sensors 134 and a controller 135. The input shaft 131 is coupled to
the LS 116 such that input torque is applied to the input shaft 131
by the LS 116 and such that the input shaft 131 is rotated at the
input rotational speed by the LS 116. The output shaft 132 is
coupled to the downstream components 120 such that the output shaft
132 applies output torque to the downstream components 120 and such
that the downstream components 120 are rotated at the output
rotational speed by the output shaft 132. The input torque is
transmitted from the input shaft 131 to the output shaft 132 via
the clutches 133. The clutches 133 can include at least a first
clutch 1331 and a second clutch 1332. The sensors 134 can be
operably disposed on the input shaft 131 and the output shaft 132
to sense rotational speeds thereof. The controller 135 is
configured to control openings and closings of the clutches 133
(i.e., to control the openings and closings of the first clutch
1331 and the second clutch 1332 in an alternating sequence)
according to readings of the sensors 134 and according to an
upshifting algorithm. According to the upshifting algorithm which
is designed to control upshifts (i.e., from first gear to second
gear, from second gear to third gear, etc.), the torque applied by
the downstream components 120 (i.e., the drag torque) is used to
reduce the output rotational speed to an output speed of a gear
into which the transmission assembly 130 is shifting. This will be
described in further detail with reference back to FIG. 2.
[0034] As shown in FIG. 2 and, in accordance with embodiments, an
execution of the controlling of the openings and the closings of
the clutches 133 will now be described. Initially, the first clutch
1331 is closed in a first gear during a first ramping-up of the
input rotational speed (from 0 rpm to about 4,500 rpm) and is
opened at a first predefined output rotational speed (at about
14,000 rpm). The drag torque applied by the downstream components
120 is then used to reduce the output rotational speed to the
output speed of a second gear and the second clutch 1332 is closed
in the second gear when the output rotational speed reaches the
output speed of the second gear. The second clutch 1332 remains
closed during a second ramping-up of the input rotational speed
(from about 4,500 rpm to about 6,200 rpm) and is opened at a second
predefined output rotational speed (at about 14,000 rpm). The drag
torque applied by the downstream components 120 is then used to
reduce the output rotational speed to the output speed of a third
gear and the first clutch 1331 is closed in the third gear when the
output rotational speed reaches the output speed of the third gear.
The first clutch 1331 remains closed during a third ramping-up of
the input rotational speed (from about 6,200 rpm to about 8,700
rpm) and is opened at a second predefined output rotational speed
(at about 12,500 rpm). The drag torque applied by the downstream
components 120 is then used to reduce the output rotational speed
to the output speed of a fourth gear and the second clutch 1332 is
closed in the fourth gear when the output rotational speed reaches
the output speed of the fourth gear. The second clutch 1332 remains
closed during a fourth ramping-up of the input rotational speed
(from about 8,700 rpm to about 18,000 rpm).
[0035] As shown in FIG. 2, the output rotational speed can be
reduced to the output speed of the gear into which the transmission
assembly 130 is shifting at one of a substantially constant input
rotational speed (see, e.g., the upshifts from the first gear to
the second gear and from the second gear to the third gear) and a
variable input rotational speed (see, e.g., the upshift from the
third gear to the fourth gear).
[0036] Technical effects and benefits of the disclosure are the
provision of minimal speed changes during upshifts resulting in
reduced torque transients. This leads to reduced torque transients
that are passed on to downstream components and results in
increased life and reliability of the downstream and transmission
driveline components. The shifting methodology also results in
reduced slippage and wear of the transmission clutch
components.
[0037] While the disclosure is provided in detail in connection
with only a limited number of embodiments, it should be readily
understood that the disclosure is not limited to such disclosed
embodiments. Rather, the disclosure can be modified to incorporate
any number of variations, alterations, substitutions or equivalent
arrangements not heretofore described, but which are commensurate
with the spirit and scope of the disclosure. Additionally, while
various embodiments of the disclosure have been described, it is to
be understood that the exemplary embodiment(s) may include only
some of the described exemplary aspects. Accordingly, the
disclosure is not to be seen as limited by the foregoing
description, but is only limited by the scope of the appended
claims.
* * * * *