US5072580A
Expired / Lapsed
US
⏱️ 0.0 years remaining
System for operating gas turbine jet engine with fan damage
Assignee: RTX Corp
•
Filing: 1990-07-17
•
Granted: 1991-12-17
•
Expires: 2010-07-17
Abstract
Abstract Normal high load operation automatically varies nozzle area to maintain an optimum engine pressure ratio (EPR). An error signal representing fan damage is established by comparing the actual EPR to the predicted EPR. Compressor stalls are also monitored. In response to these signals a minimum nozzle area is set and modified. Automatic operation to hold EPR and afterburning is inhibited. Further signals representing satisfactory operation may reset the inhibiting action.
Inventors
- 👤 Gregory S. Patterson
- 👤 James B. Kelly
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 15:01
CPC Classifications
F; F02; F02K; F02K1/00; F02K1/06; F02K1/15; F02K1/16
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
267 words
A gas turbine engine having: a compressor; a turbine; an augmentor; a variable area exhaust nozzle; a known anticipated EPR value for any operating airflow and nozzle area condition, representing an undamaged compressor; EPR sensing means for sensing the actual EPR and producing an actual EPR signal; nozzle position sensing means for determining nozzle area; nozzle adjusting means for varying the nozzle area; stall detecting means; an EPR control mode comprising said nozzle adjusting means responsive to said EPR sensing means; a base control mode comprising a fixed nozzle area operation mode; characterized by: EPR error calculation means for establishing a quantitative actual EPR error signal by comparing the actual EPR signal to said anticipated EPR value; fan damage detect means defining a tolerable EPR fan damage error; damage comparison means for comparing said actual EPR error signal to said tolerable EPR fan damage error of said fan damage detect means and establishing a fan damage signal, if said EPR error signal exceeds said tolerable EPR fan damage error; a stall detect means for detecting an immediately preceding stall; fan damage accommodation means defining a predicted stall limit nozzle area as a function of potential EPR error signal, and including damage accommodation comparison means for applying said actual EPR error signal as said potential EPR error of said fan damage accommodation means and determining a corresponding nozzle area; and minimum area limit means responsive to said damage accommodation means, or limiting the minimum area of said nozzle to said corresponding area, but only in the presence of a detected fan damage signal and an immediately preceeding stall.
Claim 2
Dependent Claim
267 words
A gas turbine engine having: a compressor; a turbine; an augmentor; a variable area exhaust nozzle; a known anticipated EPR value for any operating airflow and nozzle area condition, representing an undamaged compressor; EPR sensing means for sensing the actual EPR and producing an actual EPR signal; nozzle position sensing means for determining nozzle area; nozzle adjusting means for varying the nozzle area; stall detecting means; an EPR control mode comprising said nozzle adjusting means responsive to said EPR sensing means; a base control mode comprising a fixed nozzle area operation mode; characterized by: EPR error calculation means for establishing a quantitative actual EPR error signal by comparing the actual EPR signal to said anticipated EPR value; fan damage detect means defining a tolerable EPR fan damage error; damage comparison means for comparing said actual EPR error signal to said tolerable EPR fan damage error of said fan damage detect means and establishing a fan damage signal, if said EPR error signal exceeds said tolerable EPR fan damage error; a stall detect means for detecting an immediately preceding stall; fan damage accommodation means defining a predicted stall limit nozzle area as a function of potential EPR error signal, and including damage accommodation comparison means for applying said actual EPR error signal as said potential EPR error of said fan damage accommodation means and determining a corresponding nozzle area; and minimum area limit means responsive to said damage accommodation means, or limiting the minimum area of said nozzle to said corresponding area, but only in the presence of a detected fan damage signal and an immediately preceeding stall.
Claim 3
Dependent Claim
107 words
A gas turbine engine as in claim 1: means for setting a fan damage flag in response to a fan damage signal but only in the presence of a detected immediately preceeding stall, said fan damage detect means also defining a tolerable EPR sensor error; said damage comparison means also including means for comparing said actual EPR error signal to said tolerable EPR sensor error and establishing a null error signal when said actual EPR error signal is less than said tolerable EPR sensor error; and means responsive to said null error signal for resetting said fan damage flag and for returning to normal EPR control mode.
Claim 4
Dependent Claim
94 words
A gas turbine engine, as in claim 1: a fan damage flag; means for setting said fan damage flag in response to said actual EPR error signal exceeding said tolerable EPR fan damage error, but only in presence of a detected immediately preceeding stall; said damage comparison means inoperative in the presence of a set stall detect flag; and said fan damage accommodation means including ratchet means operative in the presence of a said fan damage flag to increase said minimum area limit means a preselected amount in the event of a subsequent stall.
Claim 5
Dependent Claim
66 words
A gas turbine engine as in claim 3: a sensor error flag; means for setting said sensor error flag in response to said EPR actual error signal exceeding said tolerable EPR fan damage error, but only in the absence of a set stall detect flag; and said ratchet means operative also in response to a subsequent stall in the presence of a said sensor error flag.
Claim 6
Dependent Claim
23 words
A gas turbine engine as in claim 3: inhibit means for prohibiting augmentor operation in the presence of a set fan damage flag.
Claim 7
Dependent Claim
95 words
A gas turbine engine as in claim 3: said fan damage detect means also defining a tolerable EPR sensor error; said damage comparison means also including means for comparing said actual EPR error signal to said tolerable EPR sensor error and establishing a null error signal when said actual EPR error signal is less than said tolerable EPR sensor error; and means responsive to said null error signal for resetting said fan damage flag and for returning to normal EPR control mode; and said means responsive to said null error also for permitting augmentor operation.
Claim 8
Dependent Claim
30 words
A gas turbine engine as in claim 1: enable logic means for rendering said damage comparison means inoperative in response to selected logic input parameters which could produce erroneous results.
Claim 9
Dependent Claim
28 words
A gas turbine engine as in claim 7, wherein: said selected logic input parameters include a failed sensor error, a nonsteady state signal, and below minimum speed signal.
Claim 10
Dependent Claim
30 words
A gas turbine engine as in claim 1, wherein: said EPR error calculation means includes means defining said anticipated EPR value as a function of an airflow and nozzle area.
Claim 11
Dependent Claim
32 words
A gas turbine engine as in claim 1: said fan damage detect means includes means for defining tolerable EPR fan damage error as a function of total pressure at the engine inlet.
Claim 12
Dependent Claim
48 words
A gas turbine engine as in claim 1: said fan damage accommodation means also defining a limit nozzle area as of function of a preselected engine thrust, and said damage accommodation means determining the lesser of the area based on the stall limit and the are based thrust.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1994-12-16 | 1995-06-17 | 1995-12-17 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1998-12-16 | 1999-06-17 | 1999-12-17 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2002-12-16 | 2003-06-17 | 2003-12-17 | $7700.00 | Window Closed / Lapsed |