Patent US1619167A successfully refreshed from Google Patents.
Patent US4184327A successfully refreshed from Google Patents.
US4184327A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method and apparatus for rapid thrust increases in a turbofan engine
Assignee: National Aeronautics and Space Administration
•
Filing: 1977-12-09
•
Granted: 1980-01-22
•
Expires: 1997-12-09
Abstract
Abstract Upon a landing approach, the normal compressor stator schedule of a fan speed controlled turbofan engine is temporarily varied to substantially close the stators to thereby increase the fuel flow and compressor speed in order to maintain fan speed and thrust. This running of the compressor at an off-design speed substantially reduces the time required to subsequently advance the engine speed to the takeoff thrust level by advancing the throttle and opening the compressor stators.
Inventors
- 👤 Jack E. Cornett
- 👤 Ralph C. Corley
- 👤 Thomas O. Fraley
- 👤 Andrew A. Saunders, Jr.
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 17:38
CPC Classifications
F; F02; F02C; F02C9/00; F02C9/48; F02C9/50; F02C9/54
Claims Analysis
Total Claims: 29
Claim 1
Independent Claim
75 words
In a turbofan engine having a fuel control which operates in response to both sensed fan speed and throttle position, and a compressor stator whose normal angle schedule is controlled by a stator control in response to core speed, an improved stator control comprising: means for generating a reset signal as a function of throttle position; and means for modifying said normal stator angle schedule by application of said reset signal to said stator control.
Claim 2
Dependent Claim
75 words
In a turbofan engine having a fuel control which operates in response to both sensed fan speed and throttle position, and a compressor stator whose normal angle schedule is controlled by a stator control in response to core speed, an improved stator control comprising: means for generating a reset signal as a function of throttle position; and means for modifying said normal stator angle schedule by application of said reset signal to said stator control.
Claim 3
Dependent Claim
40 words
An improved stator control as in claim 1 wherein said normal stator angle schedule is modified so as to move the stator to a more closed position to thereby result in a higher core speed for a given fan speed.
Claim 4
Dependent Claim
21 words
An improved stator control as in claim 2 wherein said reset signal is scheduled for a predetermined range of throttle positions.
Claim 5
Dependent Claim
31 words
An improved stator control as in claim 2 wherein said reset signal decreases in proportion to the degree of advancement of said throttle position over a predetermined range of throttle positions.
Claim 6
Dependent Claim
22 words
An improved stator control as in claim 2 wherein said reset signal is zero for all throttle positions above a predetermined position.
Claim 7
Dependent Claim
26 words
An improved stator control as in claim 1 wherein said normal stator angle is modified by an angle schedule within the range of 0° to 40°.
Claim 8
Dependent Claim
23 words
An improved normal stator control as in claim 1 wherein said stator angle schedule is modified within a time period of one second.
Claim 9
Dependent Claim
24 words
An improved stator control as in claim 1 wherein said normal stator angle schedule is modified at a minimum rate of 30° per second.
Claim 10
Dependent Claim
40 words
An improved stator control as in claim 1 wherein said normal stator angle schedule is modified so as to move the stator to a more open position to thereby result in a higher fan speed for a given core speed.
Claim 11
Dependent Claim
75 words
In a turbofan engine having a fuel control which operates in response to both sensed fan speed and throttle position, a method of varying the compressor stator angle comprising the steps of: generating a first signal as a function of core speed; generating a second signal as a function of throttle position; summing said first and second signals to obtain a control signal; and varying the compressor stator angle in response to said control signal.
Claim 12
Dependent Claim
75 words
In a turbofan engine having a fuel control which operates in response to both sensed fan speed and throttle position, a method of varying the compressor stator angle comprising the steps of: generating a first signal as a function of core speed; generating a second signal as a function of throttle position; summing said first and second signals to obtain a control signal; and varying the compressor stator angle in response to said control signal.
Claim 13
Dependent Claim
22 words
The method of claim 10 wherein the step of generating said first signal includes the steps of converting to core corrected speed.
Claim 14
Dependent Claim
18 words
The method of claim 10 wherein said second signal is generated for a predetermined range of throttle positions.
Claim 15
Dependent Claim
29 words
the method of claim 10 wherein said second signal generated decreases in proportion to the degree of advancement of said throttle position over a predetermined range of throttle positions.
Claim 16
Dependent Claim
20 words
The method of claim 10 wherein said second signal generated is zero for all throttle positions above a predetermined position.
Claim 17
Dependent Claim
23 words
The method of claim 10 wherein the summing step includes the additional step of limiting the rate at which the summing step occurs.
Claim 18
Dependent Claim
31 words
The method of claim 15 wherein the limiting step provides for summing at one rate when said second signal is increasing and at another rate when said second signal is decreasing.
Claim 19
Dependent Claim
41 words
The method of claim 10 wherein, when said second signal is increasing, said stator angle is varied so as to close the stator angle and when it is decreasing said stator angle is varied so as to open the stator angle.
Claim 20
Dependent Claim
30 words
The method of claim 17 and including the additional step, when said second signal is increasing, of allowing the core speed to increase while maintaining a substantially constant fan speed.
Claim 21
Dependent Claim
23 words
The method of claim 17 and including the additional step, when said second signal is decreasing, of allowing the fan speed to increase.
Claim 22
Dependent Claim
17 words
The method of claim 19 and including the additional step of allowing the core speed to decrease.
Claim 23
Dependent Claim
100 words
In a turbofan engine having a variable compressor stator whose angle is normally varied in accordance with a schedule responsive to core speed and a fuel control which operates in response to both sensed fan speed and throttle position, a method of facilitating a rapid change from a first thrust output level to a substantially increased second thrust output level comprising the steps of: varying the normal stator angle schedule so as to move the stator toward the closed position; and allowing the speed of the compressor to increase to the level required to maintain the first thrust output level.
Claim 24
Dependent Claim
100 words
In a turbofan engine having a variable compressor stator whose angle is normally varied in accordance with a schedule responsive to core speed and a fuel control which operates in response to both sensed fan speed and throttle position, a method of facilitating a rapid change from a first thrust output level to a substantially increased second thrust output level comprising the steps of: varying the normal stator angle schedule so as to move the stator toward the closed position; and allowing the speed of the compressor to increase to the level required to maintain the first thrust output level.
Claim 25
Dependent Claim
24 words
The turbofan engine of claim 21 wherein the normal stator angle schedule is varied by an angle in the range of 0° to 40°.
Claim 26
Dependent Claim
20 words
The turbofan engine of claim 21 wherein the rate at which the normal stator angle schedule is varied is limited.
Claim 27
Dependent Claim
36 words
The turbofan engine of claim 21 and including the subsequent step of moving the stator to a more open position to substantially increase the amount of air to the turbine to thereby increase the fan speed.
Claim 28
Dependent Claim
22 words
The turbofan engine of claim 24 wherein the rate at which the stator is moved to a more open position is limited.
Claim 29
Dependent Claim
25 words
the turbofan engine of claim 24 and including the additional step of advancing the throttle to a position commensurate with the second thrust output level.
References Cited (Backward Citations)
US3797233A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1983-01-21 | 1983-07-23 | 1984-01-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1987-01-21 | 1987-07-23 | 1988-01-22 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1991-01-21 | 1991-07-23 | 1992-01-22 | $7700.00 | Window Closed / Lapsed |