METHOD OF CONTROLLING AN OVERSPEED SAFETY SYSTEM FOR AEROENGINES AND A CONTROL CIRCUIT FOR IMPLEMENTING SAID METHOD

• US 20120116613A1
• Filed: 11/01/2011
• Published: 05/10/2012
• Est. Priority Date: 11/10/2010
• Status: Active Grant

• Current Assignee: Airbus Helicopters
• Original Assignee: Eurocopter
• Inventors: Daumas, Julien
• Granted Patent: US 9,359,961 B2
• Time in Patent Office: Days
• US Class Current: 701/3
• CPC Class Codes: F02C 9/42 specially adapted for the control of two or more plants simultaneously
• CPC Class Codes: F02C 9/46 Emergency fuel control
• CPC Class Codes: F02D 41/222 relating to the failure of sensors or parameter detection devices
• CPC Class Codes: F02D 41/266 the computer being backed-up or assisted by another circuit, e.g. analogue
• CPC Class Codes: F05D 2270/02 to control rotational speed (n)
• CPC Class Codes: F05D 2270/021 to prevent overspeed

Abstract

A method of controlling an overspeed safety system for an aircraft having at least two engines. The method includes setting said overspeed safety system for the engines, monitoring the speeds of rotation of the engines, detecting overspeed on one of the engines, shutting down the engine in question in the event of detecting overspeed, and inhibiting the operation of the overspeed safety system for the other engine(s) still in operation. The method also comprises the steps of monitoring safety parameters associated with the operation and/or the shutting down of the engine that has been shut down; and maintaining the inhibition or resetting the overspeed safety system for the other engine(s) still in operation, as a function of one or more safety parameters.

Claims

1. A method of controlling an overspeed safety system for an aircraft having at least two engines (M1, M2), the method including setting said overspeed safety system for the engines (M1, M2), in monitoring the speeds of rotation of the engines (M1, M2), detecting overspeed on one of the engines (M1, M2), shutting down the engine (M1, M2) in question in the event of detecting overspeed, and inhibiting the operation of the overspeed safety system for the other engine(s) (M1, M2) still in operation and:

monitoring safety parameters associated with the operation of the engines (M1, M2) and/or the shutting down of the engine (M1, M2) that has been shut down; and

maintaining the inhibition or resetting the overspeed safety system for the other engine(s) (M1, M2) still in operation, as a function of one or more safety parameters.

2. A control method according to claim 1, further including assessing and resetting the overspeed safety system manually.

3. A control method according to claim 1, further including resetting the overspeed safety system in an automatic manner.

4. A control method according to claim 1, wherein, in the event of overspeed of the first engine (M1, M2), the method includes selecting the power of said first engine so as to authorize shutdown of the overspeeding second engine.

5. A control method according to claim 1, wherein, in the event of the first engine (M1, M2) overspeeding, the method includes using a dedicated control independent of the power selector to authorize shutdown of the overspeeding second engine.

6. A control method according to claim 3, further comprising automatically resetting after the duration of a timeout.

7. A control method according to claim 3, further comprising detecting the end of the electromagnetic disturbance, and resetting the overspeed safety system automatically.

8. A control method according to claim 3, wherein, for an aircraft of the helicopter type, the method further comprises automatically resetting after rotor transients, e.g. transients that are functions of the free turbine speed (NTL) of one of the engines (M1, M2) and/or the speed of the rotor.

9. A control method according to claim 8, wherein, after detecting overspeed on the first engine (M1, or M2 respectively) corresponding to a free turbine speed (NTL) greater than a value V1, the method includes authorizing shutdown of the second engine (M2, or M1 respectively) after generating and detecting firstly the inhibition of the overspeed safety system on the second engine (M2, or M1 respectively) and secondly a free turbine speed (NTL) less than the value V2 for the second engine (M2, or M1 respectively).

10. A control method according to claim 9, wherein, after detecting a free turbine speed (NTL) of the second engine (M2, or M1 respectively) that is greater than the value V1, the method includes shutting down the second engine (M2, or M1 respectively).

11. A control method according to claim 8, wherein, after detecting overspeed on the first engine (M1, or M2 respectively) corresponding to a free turbine speed (NTL) greater than a value V1, the method includes authorizing shutdown of the second engine (M2, or M1 respectively) after generating and detecting firstly the inhibition of the overspeed safety system on the second engine (M2, or M1 respectively), and secondly a free turbine speed (NTL) less than a value V2 of the first engine (M1, or M2 respectively).

12. A control method according to claim 3, including engaging resetting automatically after detecting that the overspeeding engine (M1, M2) has stopped.

13. A control method according to claim 12, including using oil low-pressure information indicating that the engine (M1, M2) has stopped in order to reset automatically the overspeed safety system of the other engine (M2, M1).

14. A control circuit for an overspeed safety system of an aircraft having at least two engines (M1, M2) and for implementing the control method in accordance with claim 1, said control circuit including means for detecting overspeed on each of the engines (M1, M2), means for shutting down a first overspeeding engine, and cross inhibition means for deactivating the overspeed safety system for at least one other engine that is still powered after the first engine has been shut down, wherein the circuit includes means for resetting the overspeed safety system for at least one other engine that is still powered so as to reactivate the function providing protection against said other engine taking on an overspeed condition.

15. A control circuit according to claim 14, wherein the resetting means comprises a manual member actuated by a member of the crew of the aircraft.

16. A control circuit according to claim 14, wherein the resetting means comprise automatic means for monitoring a certain number of operating and/or shutdown parameters of the first engine (M1, M2) and means for automatically reactivating the overspeed safety system for at least one engine that continues to be powered.

17. An aircraft of the rotorcraft or helicopter type including a control circuit in accordance with claim 14.