Turbine engine control system providing electronic power turbine governor and temperature/torque limiting

• US 6,282,882 B1
• Filed: 10/14/1999
• Issued: 09/04/2001
• Est. Priority Date: 12/11/1998
• Status: Expired due to Fees

• Current Assignee: Alliedsignal Inc. (Honeywell International Inc.)
• Original Assignee: Alliedsignal Inc. (Honeywell International Inc.)
• Inventors: Demers, Dennis G., Dudd, John E. Jr.
• Primary Examiner(s): Casaregola, Louis J.
• Application Number:
  US09/418,053
• Time in Patent Office: 691 Days
• Field of Search: 60/391.41, 60/392.81
• US Class Current: 60/790
• CPC Class Codes: F02C 7/26 Starting; Ignition
• CPC Class Codes: F02C 9/28 Regulating systems responsive to plant or ambient parameters, e.g. temperature, pressure, rotor speed F02C9/30 - F02C9/38, F02C9/44 take precedence
• CPC Class Codes: F02C 9/36 characterised by returning of fuel to sump F02C9/38 takes precedence
• CPC Class Codes: F05D 2270/112 by limiting temperatures
• CPC Class Codes: F05D 2270/114 by limiting mechanical stresses
• CPC Class Codes: F05D 2270/3032 excessive temperatures, e.g. caused by overheating

Abstract

A turbine engine (49) fuel delivery system of the type including a pneumatic governor has an electronic governor and an engine excess stress avoidance feature which disable the pneumatic governor (70) so long as the engine speed exceeds a prescribed value and an electronic control unit (45) continues to function properly. The system transfers governing responsibility to the electronic control unit (45) which controls a torque motor and solenoid valve fuel diversion line (22). The system monitors an engine (49) operating parameter such as gas generator speed (37), power turbine speed, engine output torque, or engine temperature and further diminishes fuel flow to the engine (49) when the monitored parameter exceeds a threshold value. The system resumes normal speed governoring flow when that parameter returns to an acceptable level The system also senses rotor blade pitch to reduce rotor droop and increases fuel flow to the engine (49) when the pitch (44) increases, and decreasing the fuel flow to the engine (49) when the rotor blade pitch (44) decreases.

Claims

1. An aircraft having an engine and an engine fuel supply system including a fuel pump, a fuel control valve for controlling the flow of fuel from the pump to the engine and a pneumatic engine speed governor, the improvement comprising:

a controllable fuel flow bypass for selectively diverting fuel exiting the control valve away from the engine and back to the fuel pump thereby decreasing the rate of fuel flow to the engine; and

means for disabling the pneumatic engine speed governor and selectively enabling the fuel flow bypass when the engine reaches normal idle speed whereby the fuel flow bypass may assume the engine speed governing function.

2. The improvement of claim 1, wherein the fuel flow bypass includes a normally closed solenoid operable valve and a torque motor control valve connected in series between the control valve outlet and the fuel pump inlet.

3. The improvement of claim 1, wherein the means for disabling comprises a normally open solenoid valve connecting an air supply source to the pneumatic governor.

4. The improvement of claim 1, including an electronic control unit for supplying control signals to the fuel flow bypass and means for disabling, and means for transferring engine speed governing responsibility back to the pneumatic governor upon the occurrence of an electronic control unit malfunction.

5. A fuel delivery system for use with an aircraft turbine engine of the type having a gas generator, a generator driven turbine and a pneumatic engine speed governor, comprising a fuel control valve for supplying metered fuel flow to an engine, a fuel pump for supplying fuel from a fuel source to the fuel control valve, a first fuel bypass for diverting fuel exiting the fuel control valve away from the engine and back to the fuel pump to maintain a relatively constant pressure differential across the fuel control valve, a second fuel bypass operable independently from the first fuel bypass and for diverting fuel exiting the control valve away from the engine and back to the fuel pump to maintain at least one of turbine speed, gas generator speed, engine output torque and engine temperature below respective threshold level, and means for disabling the pneumatic engine speed governor and selectively enabling the second fuel bypass when the engine reaches normal idle speed whereby the second fuel bypass may assume the engine speed governing function.

6. The fuel delivery system of claim 5, wherein the second fuel bypass includes a normally closed solenoid actuatable valve and a second controllable valves in series between an outlet of the control valve and an inlet of the fuel pump, the selectively enabling means operating both the second controllable valve to be continuously partially open to provide a limited fuel flow path during engine start-up and the solenoid actuatable valve during engine start-up to divert fuel from the engine and maintain engine exhaust gas temperature below a threshold.

7. The fuel delivery system of claim 6, where in the selectively enabling means continuously energizes the solenoid actuatable valve during normal engine operation and selectively enables the second controllable valve to maintain at least one of turbine speed, gas generator speed, engine output torque and engine temperature below respective threshold levels.

8. The fuel delivery system of claim 6, wherein the solenoid actuatable valve is energized continuously during normal engine operation there by transferring speed control responsibility from the pneumatic governor to the second controllable valve.

9. The fuel delivery system of claim 6, wherein the second controllable valve comprises a torque motor.