AUTOMATIC AIRCRAFT ENGINE PRESSURE RATIO CONTROL SYSTEM

• US 3,813,063 A
• Filed: 07/21/1972
• Issued: 05/28/1974
• Est. Priority Date: 07/21/1972
• Status: Expired due to Term

• Current Assignee: Anthony N. Martin
• Original Assignee: Anthony N. Martin
• Inventors: Martin, Anthony N.
• Primary Examiner(s): Blix, Trygve M.
• Assistant Examiner(s): Kunin, Stephen G.
• Application Number:
  US05/274,123
• Time in Patent Office: 676 Days
• Field of Search: 60/39.15,39.28R 73/116 235/150.2,150.21 244/77R,77D,77F,77SE
• US Class Current: 244/182
• CPC Class Codes: F02C 9/42 specially adapted for the control of two or more plants simultaneously
• CPC Class Codes: Y02T 50/60 Efficient propulsion technologies, e.g. for aircraft

Abstract

An automatic thrust management system for gas turbine engines in single or multi-engine aircraft is disclosed. An engine pressure ratio limit is automatically calculated using known techniques and compared with the actual engine pressure ratio of the engine having the maximum pressure ratio for the purpose of an automatic control system. In one mode of operation, the throttles for each engine are trimmed to maintain the engine pressure ratio at the limit value. In another mode of operation, each engine is trimmed as necessary to insure that the engine pressure ratio does not exceed the limit value. The automatic thrust management system of this invention may be incorporated together with existing autothrottle systems in aircraft which control the engine throttles as a function of airspeed error.

Claims

1. A thrust management system for the turbine engines in a multi-engine aircraft, the thrust of each of said engines being adjusted in response to the position of a power lever, comprising means responsive to flight conditions for producing a signal indicative of the pressure ratio limit of said engines, means producing for each engine a signal indicative of the actual pressure ratio of said engine, a maximum selector receiving each of said actual engine pressure ratio signals and selecting the maximum signal therefrom, means comparing said maximum engine pressure ratio signal with said pressure ratio limit signal to produce therefrom a pressure ratio error signal, and means responsive to said error signal for varying the thrust of each of said engines in a direction to null said error signal.

2. A thrust management system as in claim 1 in which said thrust adjusting means includes means for varying the position of the power levers for each of said engines.

3. A thrust management system as in claim 1 in which each engine has a fuel control associated therewith and further including means for comparing the actual engine pressure ratio signal for each engine with said maximum pressure ratio signal to produce an engine equalization error signal for each engine, and means responsive to each said engine equalization error signal for adjusting the fuel control setting of each engine in a direction to null said equalization error signal and equalize the thrust produced by each engine.

4. A thrust management system for the turbine engines in a multi-engine aircraft having an autothrottle system in which is produced an airspeed error signal proportional to the difference between a pilot selected airspeed and the actual airspeed of the aircraft and automatically regulating a power lever actuating means to adjust the position of the engine power levers in response to said speed error signal, comprising means responsive to the flight conditions of said aircraft for producing a signal indicative of the pressure ratio limit for said engines, means producing for each engine a signal indicative of the actual pressure ratio of said engine, a maximum selector receiving said actual engine pressure ratio signals and selecting the maximum signal therefrom, means comparing said maximum engiNe pressure ratio signal with said pressure ratio limit signal to produce therefrom a pressure ratio error signal, a mode selector, means connecting said pressure ratio error signal and said airspeed error signal to said mode selector as inputs thereto, means connecting the output of said mode selector to said power lever actuating means, and mode control means including pilot actuated switch means connected with said mode selector for actuating said mode selector and causing said mode selector to pass therethrough one of said error signals to said power lever actuating means.

5. A thrust management system as in claim 4 in which said mode control means includes a first switch for actuating said mode selector to cause said mode selector to pass only said pressure ratio error signal therethrough.

6. A thrust management system as in claim 4 in which said mode control means includes a second switch for actuating said mode selector to cause said mode selector to pass said airspeed error signal therethrough when said pressure ratio error signal is indicative of an acutal engine pressure ratio below the pressure ratio limit, and to cause said mode selector to pass said pressure ratio error signal when said pressure ratio signal is indicative of an actual engine pressure ratio above the pressure ratio limit.

7. A thrust management system as in claim 6 in which said mode control means further includes means responsive to actuation of said second switch for causing said mode selector to pass therethrough said engine pressure ratio error signal when the said airspeed error signal is above a predetermined magnitude.

8. A process for controlling the thrust produced by the turbine engines in a multi-engine aircraft, fuel being provided to each engine in response to the position of a power lever to vary the thrust of the engines comprising the steps of generating from selected operating conditions of said aircraft a signal indicative of the pressure ratio limit of said engines, producing for each engine a signal indicative of the actual pressure ratio thereof, selecting from said plurality of actual pressure ratio signals the maximum actual pressure ratio signal, comparing said maximum actual pressure ratio signal with said pressure ratio limit signal and producing therefrom a pressure ratio error signal, producing an airspeed error signal proportional to the differece between a desired airspeed and the actual airspeed of the aircraft, feeding said pressure ratio error signal and said airspeed error signal to a mode selector, one of said error signals being passed through said mode selector to vary the position of said power levers in response thereto, and selecting the one of said error signals passed through said mode selector in response to a pilot actuated switch.