US4130872A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method and system of controlling a jet engine for avoiding engine surge
Assignee: United States Department of the Air Force
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Filing: 1975-10-10
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Granted: 1978-12-19
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Expires: 1995-10-10
Abstract
Abstract A jet engine is controlled by placing time variant total pressure probes at the entry plane and the discharge plane of a jet engine fan. The pressure values at the probes are converted into electrical signals, filtered, and then fed to meters where the root-mean-square (RMS) values of the electrical signals are determined. The RMS values are fed to a computer which computes the ratio of the two RMS values and this ratio is fed to a comparison circuit which generates a difference signal representing the difference between the RMS ratio and a predetermined limit value. If the RMS ratio equals the limit value, then the operating point of a fan is altered by either changing the nozzle area, changing the fan speed, or changing the altitude or Mach number.
Inventors
- 👤 Gary J. Haloff
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 11:42
CPC Classifications
F; F02; F02K; F02K1/00; F02K1/06; F02K1/15; F02C; F02C9/00; F02C9/16; G; G01; G01M; G01M15/00
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
160 words
A system for automatically avoiding a surge of a jet engine having a fan with an entry plane and a discharge plane, comprising: a. a first time variant total pressure probe positioned at the entry plane of the jet engine fan; b. a second time variant total pressure probe positioned at the discharge plane of the jet engine fan; c. first and second means for converting responses of the first and second pressure probes respectively into corresponding electrical signals; d. first and second RMS meters fed respectively by the first and second converting means; e. a computer fed by the first and second RMS meters for determining the ratio of the outputs of second RMS meter to the first RMS meter; f. a threshold circuit fed by the computer wherein the ratio of the outputs of the first and second RMS meters is compared with a predetermined limit value; and g. means for controlling the operating point of the fan.
Claim 2
Independent Claim
160 words
A system for automatically avoiding a surge of a jet engine having a fan with an entry plane and a discharge plane, comprising: a. a first time variant total pressure probe positioned at the entry plane of the jet engine fan; b. a second time variant total pressure probe positioned at the discharge plane of the jet engine fan; c. first and second means for converting responses of the first and second pressure probes respectively into corresponding electrical signals; d. first and second RMS meters fed respectively by the first and second converting means; e. a computer fed by the first and second RMS meters for determining the ratio of the outputs of second RMS meter to the first RMS meter; f. a threshold circuit fed by the computer wherein the ratio of the outputs of the first and second RMS meters is compared with a predetermined limit value; and g. means for controlling the operating point of the fan.
Claim 3
Dependent Claim
25 words
A system for automatically avoiding a surge of a jet engine according to claim 1 wherein the first and second converting means are pressure-to-electrical transducers.
Claim 4
Dependent Claim
38 words
A system for automatically avoiding a surge of a jet engine according to claim 2 which further comprises first and second filters interposed between the first and second pressure-to-electrical transducers and the first and second RMS meters respectively.
Claim 5
Dependent Claim
45 words
A system for automatically avoiding a surge of a jet engine according to claim 3 which further comprises first and second analog-to-digital converters interposed one each between the computer and the first and second RMS meters respectively, and wherein the computer is a digital computer.
Claim 6
Dependent Claim
38 words
A system for automatically avoiding a surge of a jet engine according to claim 3 wherein the means for controlling the operating point of the fan is a means for controlling the nozzle area of the jet engine.
Claim 7
Dependent Claim
34 words
A system for automatically avoiding a surge of a jet engine according to claim 3 wherein the means for controlling the operating point of the fan is a means for controlling the speed thereof.
Claim 8
Dependent Claim
37 words
A system for automatically avoiding a surge of a jet engine according to claim 3 wherein the means for controlling the operating point of the fan is a means for controlling the flight altitude and Mach number.
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) | 1981-12-18 | 1982-06-19 | 1982-12-19 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1985-12-18 | 1986-06-19 | 1986-12-19 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1989-12-18 | 1990-06-19 | 1990-12-19 | $7700.00 | Window Closed / Lapsed |