Method and a device for protecting an overspeeding rotorcraft engine

Patent metadata

Field	Value
Publication number	US-9522740-B2
Application number	US-201414303056-A
Country	US
Kind code	B2
Filing date	Jun 12, 2014
Priority date	Jun 27, 2013
Publication date	Dec 20, 2016
Grant date	Dec 20, 2016

Abstract

A method of stopping an overspeeding engine ( 4 ) of a rotorcraft ( 1 ). A protection device stops the overspeeding engine ( 4 ) on condition of a comparison between a mechanical power requirement ( 19 ) of the rotorcraft ( 1 ) and a predefined power threshold ( 22 ). Stopping of the overspeeding engine ( 4 ) is authorized by the protection device ( 8 ) on condition that said mechanical power requirement ( 19 ) is identified as being less than or equal to the predefined power threshold ( 22 ). The mechanical power requirement ( 19 ) of the rotorcraft ( 1 ) is calculated on the basis of at least one current or anticipated value for the opposing torque ( 15 ) of a main rotor ( 5 ) of the rotorcraft.

First claim

What is claimed is:

1. A method of stopping an engine of a rotorcraft when the engine is in overspeed, the rotorcraft having at least one engine driving power absorber members of the rotorcraft including at least one rotor comprising at least a main rotor having a substantially vertical axis, the method comprising:
an operation of detecting overspeed of the engine;
an operation of detecting at least one specific stage of flight of the rotorcraft, the stage of flight determining whether or not use is to be made of a protection device for stopping the engine in an event of overspeed of the engine being detected, wherein the specific stage of flight is identified by a mechanical power requirement of the rotorcraft that needs to be delivered by the at least one engine;
stopping of the engine in overspeed by the protection device depending on an operation of comparing the mechanical power requirement and a predefined power threshold, with the engine in overspeed being stopped by the protection device on condition that the mechanical power requirement is identified as being less than or equal to the predefined power threshold;
depending on current state of flight of the rotorcraft, deducing by calculating a mechanical power requirement of the rotorcraft, by identifying at least an opposing torque generated by at least one of the power absorber members including at least the at least one main rotor;
comparing the previously deduced mechanical power requirement with the power threshold and generating a setpoint identifying the mechanical power requirement relative to the power threshold; and
detecting a speed of rotation of the engine and if the engine is in overspeed, stopping the engine by the protection device conditional on a previously generated setpoint.

2. A method according to claim 1 , wherein the mechanical power requirement is deduced from a current value of the at least one opposing torque.

3. A method according to claim 1 , wherein the mechanical power requirement is deduced from an anticipated value of the at least one opposing torque calculated from flight commands generated by a pilot of the rotorcraft for modifying blade pitch of the at least one rotor.

4. A method according to claim 1 , wherein when the mechanical power requirement is identified by the setpoint as being greater than or equal to the power threshold, the protection device prevents the engine in overspeed from stopping under command of a detector used in the detecting step.

5. A method according to claim 4 , wherein generation of the setpoint causes a break in continuity of a logic path for transmitting a stop order to a regulator means controlling the engine, the stop order for stopping the engine being generated by the detector identifying an overspeed situation of the engine.

6. A method according to claim 5 , wherein generation of the setpoint causes a switch placed on the logic path to be operated, the operation of the switch preventing the stop order for stopping the engine being transmitted over the logic path.

7. A method according to claim 1 , wherein when the mechanical power requirement identified by the setpoint is less than or equal to the power threshold, the protection device is authorized to stop the engine in overspeed under control of a detector used in the detecting step.

8. A method of controlling a rotorcraft engine, the rotorcraft engine driving a main rotor of a rotorcraft, the method comprising:
detecting a rotorcraft engine overspeed condition;
detecting a specific stage of flight of the rotorcraft based on a mechanical power requirement for the rotorcraft engine;
in response to the rotorcraft engine overspeed condition and the mechanical power requirement being less than a predefined power threshold, stopping the rotorcraft engine using an overspeed protection device;
depending on current state of flight of the rotorcraft, deducing by calculating a mechanical power requirement of the rotorcraft, by identifying at least an opposing torque generated by at least one of the power absorber members including at least the at least one main rotor;
comparing the previously deduced mechanical power requirement with the power threshold and generating a setpoint identifying the mechanical power requirement relative to the power threshold; and
detecting a speed of rotation of the rotorcraft engine and if the rotorcraft engine is in overspeed, stopping the rotorcraft engine by the protection device conditional on a previously generated setpoint.

9. The method of claim 8 , wherein the mechanical power requirement is determined based on an opposing torque generated by the main rotor.

10. The method of claim 8 , further comprising, in response to the rotorcraft engine overspeed condition and the mechanical power being greater than the predefined power threshold, maintaining the rotorcraft engine in a running condition.

Assignees

• Airbus Helicopters

Inventors

• Domingo Benoit
• Dumur Guillaume
• Bailly Stephane

Classifications

• F05D2220/329

  in helicopters · CPC title

• F05D2270/331

  Mechanical loads · CPC title

• F01D21/02 Primary

  Shutting-down responsive to overspeed · CPC title

• Y02T50/671

  Cross-Sectional Technologies · mapped topic

• B64D31/06 Primary

  actuated automatically · CPC title