Air turbine starter torque control system

Patent metadata

Field	Value
Publication number	US-11655765-B2
Application number	US-202117523470-A
Country	US
Kind code	B2
Filing date	Nov 10, 2021
Priority date	Dec 22, 2020
Publication date	May 23, 2023
Grant date	May 23, 2023

Abstract

An enhanced engine starter system controls an air turbine starter at the startup of operation of a turbine engine. The engine starter system includes an air turbine starter (ATS) that operates in accordance with more than one speed/torque curve during the startup procedure. A controller commands the starter control valve to provide a regulated pressure to the ATS in accordance with a first speed/torque curve to initiate the gas turbine engine startup without exceeding a maximum or design limiting torque. Overall duration of the startup procedure is reduced by the controller subsequently operating the ATS in accordance with a second speed/torque curve having a higher operational pressure once the ATS reaches a predetermined transition speed. The torque at the predetermined transition speed on the higher pressure second curve remains less than the design limiting torque, but provides a higher torque as compared to the first speed/torque curve to reduce the duration of the startup procedure.

First claim

What is claimed is:

1. A method of starting a turbine engine comprising the steps of:
a control valve receiving an external flow of pressurized air and regulating a pressure of the external flow to provide an input flow of pressurized air to an air turbine starter;
the air turbine starter receiving the input flow of pressurized air from the control valve, wherein the air turbine starter rotates during a startup procedure of the turbine engine to apply torque to the turbine engine to start the turbine engine;
a controller commanding the control valve to provide a first input pressure to operate the air turbine starter in accordance with a first speed/torque curve until a speed of the air turbine starter reaches a predetermined transition speed;
detecting that the speed of the air turbine starter has reached the predetermined transition speed; and
in response to the speed of the air turbine starter reaching the predetermined transition speed, the controller commanding the control valve to provide a second input pressure to operate the air turbine starter in accordance with a second speed/torque curve until the speed of the air turbine starter reaches a predetermined cutout speed, wherein a torque at a given speed along the second speed/torque curve is greater than a torque at the given speed along the first speed/torque curve.

2. The method of starting the turbine engine of claim 1 , wherein an initial torque applied by the air turbine starter at zero speed on the first speed/torque curve is below a design limiting torque of the turbine engine.

3. The method of starting the turbine engine of claim 1 , wherein a torque applied by the air turbine starter at the predetermined transition speed on the second speed/torque curve is below a design limiting torque of the turbine engine.

4. The method of starting the turbine engine of claim 1 , wherein an initial torque on the first speed/torque curve and the torque at the predetermined transition speed on the second speed/torque curve are equal.

5. The method of starting the turbine engine of claim 1 , further comprising monitoring the speed of the air turbine starter by the controller receiving a speed signal off of the turbine engine.

6. The method of starting the turbine engine of claim 1 , further comprising monitoring the speed of the air turbine starter by the controller receiving a speed signal directly off of the air turbine starter.

7. The method of starting the turbine engine of claim 1 , wherein a default position of the control valve in the absence of the external flow of pressurized air is a closed position.

8. The method of starting the turbine engine of claim 1 , wherein a position of the control valve when the air turbine starter is operating in accordance with the second speed/torque curve is a more open position as compared to a position of the control valve when the air turbine starter is operating in accordance with the first speed/torque curve.

9. The method of starting the turbine engine of claim 8 , wherein the position of the control valve when the air turbine starter is operating in accordance with the second speed/torque curve is a fully open position.

10. The method of starting the turbine engine of claim 1 , further comprising decoupling the air turbine starter from the turbine engine when the speed of the air turbine starter reaches the predetermined cutout speed.

11. An engine starter system comprising:
an air turbine starter that receives an input flow of pressurized air, wherein the air turbine starter is configured to rotate during a startup procedure of a turbine engine to start the turbine engine;
a starter control valve that receives an external flow of pressurized air and regulates the external flow to provide the input flow of pressurized air to the air turbine starter;
a controller configured to command the starter control valve to provide a first input pressure to operate the air turbine starter in accordance with a first speed/torque curve until a speed of the air turbine starter reaches a predetermined transition speed; and
in response to the air turbine starter reaching the predetermined transition speed, the controller is configured to command the starter control valve to provide a second input pressure to operate the air turbine starter in accordance with a second speed/torque curve until the speed of the air turbine starter reaches a predetermined cutout speed, wherein a torque at a given speed along the second speed/torque curve is greater than a torque at the given speed along the first speed/torque curve.

12. The engine starter system of claim 11 , wherein the controller is configured to receive a speed signal off of the turbine engine and is further configured to monitor the speed of the air turbine starter by monitoring the speed signal.

13. The engine starter system of claim 11 , wherein the controller further is configured to monitor a speed of the air turbine starter by monitoring a speed signal directly off of the air turbine starter.

14. The engine starter system of claim 11 , wherein a default position of the starter control valve in the absence of any controller command is a closed position.

15. The engine starter system of any of claim 11 , wherein a position of the starter ccntrol valve when the air turbine starter is operating in accordance with the second speed/torque curve is a more open position as compared to a position of the starter control valve when the air turbine starter is operating in accordance with the first speed/torque curve.

16. The engine starter system of claim 15 , wherein the position of the control valve when the air turbine starter is operating in accordance with the second speed/torque curve is a fully open position.

17. The engine starter system of claim 11 , wherein the control valve is a three-state regulator control valve.

18. The engine starter system of claim 11 , wherein the air turbine starter comprises a turbine and gearing.

19. The engine starter system of claim 11 , further comprising a decoupler configured as a clutch configured to decouple the air turbine starter from the turbine engine when the speed of the air turbine starter reaches the predetermined cutout speed.

Assignees

• Parker Hannifin Corp

Inventors

• Dow Steven C

Classifications

• F02N7/12

  the engines being of rotary type, e.g. turbines (F02N7/14 takes precedence) · CPC title

• F05D2260/85

  Starting · CPC title

• F02C7/277 Primary

  the starter being a {separate} turbine · CPC title

• F05D2270/052

  Torque · CPC title

• F05D2270/02

  to control rotational speed (n) · CPC title