System and method for operating a turboprop engine

Patent metadata

Field	Value
Publication number	US-12435674-B2
Application number	US-201916551177-A
Country	US
Kind code	B2
Filing date	Aug 26, 2019
Priority date	Jul 26, 2019
Publication date	Oct 7, 2025
Grant date	Oct 7, 2025

Abstract

There is provided a method and system for operating a turboprop engine of an aircraft. When a resulting value for Ng is between at least one upper limit and at least one lower limit, the output power is governed as a function of the target power. When the resulting value for Ng is on or outside of the at least one upper limit and the at least one lower limit, the output power is governed as a function of the maximum Ng and the minimum Ng.

First claim

The invention claimed is:

1. A method for transitioning a turboprop engine of an aircraft out of and into an idle operating regime of the turboprop engine, the method comprising:
obtaining a power governing schedule defining at least one upper gas generator speed (Ng) limit and at least one lower Ng limit of the turboprop engine, the at least one upper Ng limit defining a maximum Ng that varies as a function of a power lever position of the aircraft for producing forward thrust with a propeller of the turboprop engine and beyond an idle power lever position, the at least one lower Ng limit defining a minimum Ng that varies as a function of the power lever position, the at least one upper Ng limit and the at least one lower Ng limit diverging from the idle power lever position to define a progressive transition out of and into the idle operating regime of the turboprop engine;
receiving a target power for the turboprop engine corresponding to a current power lever position, the current power lever position corresponding to forward thrust operation of the propeller of the turboprop engine and being beyond the idle power lever position;
selecting, from the power governing schedule, a maximum Ng corresponding to the current power lever position and a minimum Ng corresponding to the current power lever position; and
in response to receiving the target power:
governing output power for the turboprop engine to achieve the target power, governing the output power including determining a requested Ng;
when the requested Ng is between the maximum Ng corresponding to the current power lever position and the minimum Ng corresponding to the current power lever position, using the requested Ng to govern the output power for the turboprop engine;
when the requested Ng is above the maximum Ng corresponding to the current power lever position, using the maximum Ng instead of the requested Ng to govern the output power for the turboprop engine; and
when the requested Ng is below the minimum Ng corresponding to the current power lever position, using the minimum Ng instead of the requested Ng to govern the output power for the turboprop engine.

2. The method of claim 1 , wherein:
the at least one upper Ng limit comprises a first upper Ng limit for flight operation and a second upper Ng limit for ground operation, the first upper Ng limit being different from the second upper Ng limit; and
the at least one lower Ng limit comprises a first lower Ng limit for flight operation and a second lower Ng limit for ground operation, the first lower Ng limit being different from the second lower Ng limit.

3. The method of claim 2 , wherein the first upper Ng limit and the first lower Ng limit meet at a common value when the power lever position is at idle.

4. The method of claim 2 , wherein the first upper Ng limit and the first lower Ng limit overlap when the power lever position is at idle.

5. The method of claim 2 , wherein the second upper Ng limit and the second lower Ng limit meet at a common value along the first lower Ng limit.

6. The method of claim 2 , wherein the first lower Ng limit and the second lower Ng limit overlap for at least a portion thereof.

7. The method of claim 2 , further comprising transitioning between the flight operation and the ground operation based on at least one criteria comprising an on-ground status.

8. The method of claim 7 , wherein the at least one criteria comprises the on-ground status and a timer condition.

9. The method of claim 7 , wherein the at least one criteria comprises the on-ground status and the power lever position.

10. The method of claim 1 , wherein providing the at least one lower Ng limit comprises selecting the minimum Ng to ensure a percentage of take-off power in case of an undetected loss of torque.

11. A system for transitioning a turboprop engine of an aircraft out of and into an idle operating regime of the turboprop engine, the system comprising:
a processing unit; and
a non-transitory computer readable medium having stored thereon program instructions executable by the processing unit for:
obtaining a power governing schedule defining at least one upper gas generator speed (Ng) limit and at least one lower Ng limit of the turboprop engine, the at least one upper Ng limit defining a maximum Ng that varies as a function of a power lever position of the aircraft for producing forward thrust with a propeller of the turboprop engine and beyond an idle power lever position, the at least one lower Ng limit defining a minimum Ng that varies as a function of the power lever position, the at least one upper Ng limit and the at least one lower Ng limit diverging from the idle power lever position to define a progressive transition out of and into the idle operating regime of the turboprop engine;
receiving a target power for the turboprop engine corresponding to a current power lever position, the current power lever position corresponding to forward thrust operation of the propeller of the turboprop engine and being beyond the idle power lever position;
selecting, from the power governing schedule, a maximum Ng corresponding to the current power lever position and a minimum Ng corresponding to the current power lever position; and
in response to receiving the target power:
governing output power for the turboprop engine to achieve the target power, governing the output power including determining a requested Ng;
when the requested Ng is between the maximum Ng corresponding to the current power lever position and the minimum Ng corresponding to the current power lever position, using the requested Ng to govern the output power for the turboprop engine;
when the requested Ng is above the maximum Ng corresponding to the current power lever position, using the maximum Ng instead of the requested Ng to govern the output power for the turboprop engine; and
when the requested Ng is below the minimum Ng corresponding to the current power lever position, using the minimum Ng instead of the requested Ng to govern the output power for the turboprop engine.

12. The system of claim 11 , wherein the at least one upper Ng limit comprises a first upper Ng limit for flight operation and a second upper Ng limit for ground operation, and wherein the at least one lower Ng limit comprises a first lower Ng limit for flight operation and a second lower Ng limit for ground operation.

13. The system of claim 12 , wherein the first upper Ng limit and the first lower Ng limit meet at a common value when the power lever position is at idle.

14. The system of claim 12 , wherein the first upper Ng limit and the first lower Ng limit overlap when the power lever position is at idle.

15. The system of claim 12 , wherein the second upper Ng limit and the second lower Ng limit meet at a common value along the first lower Ng limit.

16. The system of claim 12 , wherein the program instructions are further executable for transitioning between the flight operation and the ground operation based on at least one criteria comprising an on-ground status.

17. The system of claim 16 , wherein the at least one criteria comprises the on-ground status and a timer condition.

18. The system of claim 16 , wherein the at least one criteria comprises the on-ground status and the power lever position.

19. The system of claim 11 , wherein providing the at least one lower Ng limit comprises selecting the minimum Ng to ensure a percentage of take-off power in case of an undetected loss of torque.

20. The method of claim 1 , where

Assignees

• Pratt & Whitney Canada

Inventors

• Des Roches-Dionne Nicolas
• Lamarre Sylvain
• Charest Alexandre

Classifications

• F05D2270/335

  Output power or torque · CPC title

• F05D2270/304

  Spool rotational speed · CPC title

• F05D2270/052

  Torque · CPC title

• F05D2270/051

  Thrust · CPC title

• F05D2270/02

  to control rotational speed (n) · CPC title