Patent US5267435A successfully refreshed from Google Patents.
US5267435A
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Thrust droop compensation method and system
Assignee: General Electric Co
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Filing: 1992-08-18
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Granted: 1993-12-07
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Expires: 2012-08-18
Abstract
Abstract A control system and method provide thrust droop compensation in a gas turbine engine. A droop compensation signal is generated for increasing turbine exit temperature T 5 based on a predetermined model, and is selectively reduced for limiting the increase in temperature T 5 when the temperature T 5 is above a predetermined threshold temperature for a predetermined time. The reduced droop signal is added as a bias signal into an error signal which effects thrust droop concentration in a variable area exhaust nozzle of the engine.
Inventors
- 👤 Richard G. Frenkel
- 👤 James A. Huffman
- 👤 Jonathan A. Rennert
- 👤 Dominic Stasio
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 17:10
CPC Classifications
F; F02; F02K; F02K1/00; F02K1/06; F02K1/15; F02C; F02C9/00; F02C9/26; F02C9/28; F05; F05D; F05D2270/00; F05D2270/01; F05D2270/11; F05D2270/112
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
235 words
For a gas turbine engine having a compressor powered by a high pressure turbine (HPT), a fan powered by a low pressure turbine (LPT), an afterburner, and a variable area exhaust nozzle (VEN) for discharging exhaust gases received from said LPT to generate thrust, a control system for compensating for droop in thrust due to a transient increase in tip clearance of said HPT comprising: means for providing an error signal T 5E to said VEN for adjusting exhaust flow area of said VEN and in turn adjusting thrust of said exhaust gases discharged therethrough from said LPT, said error signal T 5E including a difference between temperature T 5 of said LPT exhaust gases and a predetermined reference temperature T 5R ; means for generating a droop compensation signal T 5D for increasing said exhaust temperature T 5 to increase said thrust, said droop signal T 5D being based on a predetermined model of said tip clearance transient increase and being responsive to said error signal T 5E ; means for selectively reducing said droop signal T 5D to generate a bias signal T 5B for selectively limiting said increase in exhaust temperature T 5 when said exhaust temperature T 5 is above a predetermined threshold temperature T 5T for a predetermined time; and means for adding said bias signal T 5B into said error signal T 5E to effect said thrust droop compensation.
Claim 2
Dependent Claim
235 words
For a gas turbine engine having a compressor powered by a high pressure turbine (HPT), a fan powered by a low pressure turbine (LPT), an afterburner, and a variable area exhaust nozzle (VEN) for discharging exhaust gases received from said LPT to generate thrust, a control system for compensating for droop in thrust due to a transient increase in tip clearance of said HPT comprising: means for providing an error signal T 5E to said VEN for adjusting exhaust flow area of said VEN and in turn adjusting thrust of said exhaust gases discharged therethrough from said LPT, said error signal T 5E including a difference between temperature T 5 of said LPT exhaust gases and a predetermined reference temperature T 5R ; means for generating a droop compensation signal T 5D for increasing said exhaust temperature T 5 to increase said thrust, said droop signal T 5D being based on a predetermined model of said tip clearance transient increase and being responsive to said error signal T 5E ; means for selectively reducing said droop signal T 5D to generate a bias signal T 5B for selectively limiting said increase in exhaust temperature T 5 when said exhaust temperature T 5 is above a predetermined threshold temperature T 5T for a predetermined time; and means for adding said bias signal T 5B into said error signal T 5E to effect said thrust droop compensation.
Claim 3
Dependent Claim
226 words
For a gas turbine engine having a compressor powered by a high pressure turbine (HPT), a fan powered by a low pressure turbine (LPT), an afterburner, and a variable area exhaust nozzle (VEN) for discharging exhaust gases received from said LPT to generate thrust, a method of compensating for droop in thrust due to a transient increase in tip clearance of said HPT comprising: providing an error signal T 5E to said VEN for adjusting exhaust flow area of said VEN and in turn adjusting thrust of said exhaust gases discharged therethrough from said LPT, said error signal T 5E including a difference between temperature T 5 of said LPT exhaust gases and a predetermined reference temperature T 5R ; generating a droop compensation signal T 5D for increasing said exhaust temperature T 5 to increase said thrust, said droop signal T 5D being based on a predetermined model of said tip clearance transient increase and being responsive to said error signal T 5E ; selectively reducing said droop signal T 5D to generate a bias signal T 5B for selectively limiting said increase in exhaust temperature T 5 when said exhaust temperature T 5 is above a predetermined threshold temperature T 5T for a predetermined time; and adding said bias signal T 5B into said error signal T 5E to effect said thrust droop compensation.
Claim 4
Dependent Claim
226 words
For a gas turbine engine having a compressor powered by a high pressure turbine (HPT), a fan powered by a low pressure turbine (LPT), an afterburner, and a variable area exhaust nozzle (VEN) for discharging exhaust gases received from said LPT to generate thrust, a method of compensating for droop in thrust due to a transient increase in tip clearance of said HPT comprising: providing an error signal T 5E to said VEN for adjusting exhaust flow area of said VEN and in turn adjusting thrust of said exhaust gases discharged therethrough from said LPT, said error signal T 5E including a difference between temperature T 5 of said LPT exhaust gases and a predetermined reference temperature T 5R ; generating a droop compensation signal T 5D for increasing said exhaust temperature T 5 to increase said thrust, said droop signal T 5D being based on a predetermined model of said tip clearance transient increase and being responsive to said error signal T 5E ; selectively reducing said droop signal T 5D to generate a bias signal T 5B for selectively limiting said increase in exhaust temperature T 5 when said exhaust temperature T 5 is above a predetermined threshold temperature T 5T for a predetermined time; and adding said bias signal T 5B into said error signal T 5E to effect said thrust droop compensation.
Claim 5
Dependent Claim
155 words
A thrust droop compensation method according to claim 2 wherein said droop signal T 5D reducing step includes: comparing said exhaust temperature T 5 with said predetermined threshold temperature T 5T ; increasing a counter index A by one for each unit of time said exhaust temperature T 5 is greater than said threshold temperature T 5T ; decreasing said counter index A by one for each unit of time said exhaust temperature T 5 is not greater than said threshold temperature T 5T ; and multiplying said droop signal T 5D by a first multiplier M 1 to generate said bias signal T 5B , said first multiplier M 1 being obtained from a predetermined first schedule having values ranging from 1.0 to zero relative to said counter index A, and having a value less than 1.0 when said index A exceeds a predetermined first threshold value A 1 corresponding with said predetermined time.
Claim 6
Dependent Claim
128 words
A method according to claim 3 wherein said predetermined first schedule includes decreasing value of M 1 for increasing values of said index A, and a first region wherein said first multiplier M 1 equals 1.0 for said index up to said first threshold value A 1 when said engine is cold, a second region wherein said first multiplier M 1 equals zero for said index A above a second threshold value A 2 greater than said first threshold value A 1 when said engine is hot, and a third region wherein said first multiplier M 1 has a value less than 1.0 and greater than zero for said index A between said first and second threshold value A 1 and A 2 when said engine is warm.
Claim 7
Dependent Claim
119 words
A method according to claim 4 wherein said droop signal T 5D reducing step further includes: multiplying said droop signal T 5D by a second multiplier M 2 to generate said bias signal T 5B , said second multiplier M 2 being obtained from a predetermined second schedule having values ranging from zero to 1.0 relative to magnitude of said thrust, said second multiplier M 2 having a value of zero for thrust up to a first threshold value P 1 , a value between zero and 1.0 from said first threshold value P 1 up to a second, greater, threshold value P 2 , and a value of 1.0 from said second threshold value P 2 and greater.
Claim 8
Dependent Claim
43 words
A method according to claim 5 wherein said thrust first threshold value P 1 is associated with intermediate rated power (IRP) of said engine for obtaining maximum dry thrust, and said second threshold value P 2 is associated with operation of said afterburner.
Claim 9
Dependent Claim
125 words
A method according to claim 5 wherein said droop signal T 5D reducing step further includes: multiplying said droop signal T 5D by a third multiplier M 3 to generate said bias signal T 5B , said third multiplier M 3 being obtained from a predetermined third schedule having values ranging from zero to 1.0 to zero relative to an inlet temperature T 2 of said engine, said third multiplier M 3 having a value of zero for said inlet temperature T 2 up to a first threshold value T L , a value of 1.0 between said first threshold value T L and a second greater, threshold value T H , and a value of zero above said second threshold value T H .
Claim 10
Dependent Claim
40 words
A method according to claim 7 wherein said first and second inlet temperature threshold values T L and T H are preselected to correspond with flight operation of said engine between which said engine is susceptible to said thrust droop.
Claim 11
Dependent Claim
30 words
A method according to claim 7 further including limiting said bias signal T 5B to prevent said exhaust temperature T 5 from exceeding a predetermined maximum temperature T 5MAX .
Claim 12
Dependent Claim
37 words
A method according to claim 9 wherein said bias signal T 5B is effected by a fourth multiplier M 4 obtained from a predetermined fourth schedule for providing maximum thrust droop compensation at startup of said engine.
Claim 13
Dependent Claim
62 words
A method according to claim 10 wherein said bias signal T 5B limiting step includes: generating a difference signal T 5d between said reference temperature T 5R and said maximum temperature T 5MAX ; and adding the minimum of said difference signal T 5d and said bias signal T 5B into said error signal T 5E to effect said thrust droop compensation.
Claim 14
Dependent Claim
27 words
A method according to claim 10 wherein said tip clearance transient increase model includes a gain, and said fourth multiplier M 4 is applied to said gain.
References Cited (Backward Citations)
US3747344A
Cited
US4455820A
Cited
US4159625A
Cited
US4139887A
Cited
US4294069A
Cited
US4337615A
Cited
US4313167A
Cited
US4467600A
Cited
US4321791A
Cited
US4581889A
Cited
US5012420A
Cited
US5048285A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1996-12-06 | 1997-06-07 | 1997-12-07 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2000-12-06 | 2001-06-07 | 2001-12-07 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2004-12-06 | 2005-06-07 | 2005-12-07 | $7700.00 | Window Closed / Lapsed |