Optical health monitoring for aircraft overheat and fire detection systems

Patent metadata

Field	Value
Publication number	US-10436652-B2
Application number	US-201715600130-A
Country	US
Kind code	B2
Filing date	May 19, 2017
Priority date	May 19, 2016
Publication date	Oct 8, 2019
Grant date	Oct 8, 2019

Abstract

Overheat and fire detection for aircraft systems includes an optical controller and a fiber optic loop extending from the optical controller. The fiber optic loop extends through one or more zones of the aircraft. An optical signal is transmitted through the fiber optic loop from the optical controller and is also received back at the optical controller. The optical controller analyzes the optical signal to determine the temperature, strain, or both experienced within the zones.

First claim

The invention claimed is:

1. A system configured to monitor temperature in a plurality of zones of an aircraft, the system comprising:
a first fiber optic cable routed through each of the plurality of zones of the aircraft system, wherein the first fiber optic cable includes fiber Bragg gratings;
an optical transmitter configured to provide an optical signal to the first fiber optic cable;
an optical receiver configured to receive an optical response from the first fiber optic cable; and
a controller operatively connected to the optical receiver and configured to determine at least one temperature and/or strain for each of the plurality of zones based on the optical response and output an indication for detected zones of the plurality of zones in which the at least one temperature and/or strain is greater than a threshold value to facilitate preventive maintenance, wherein the controller is configured to control the optical transmitter and determine the at least one temperature and/or strain for each of the plurality of zones using time division multiplexing (TDM) and/or wavelength division multiplexing (WDM).

2. The system of claim 1 , further comprising:
a second fiber optic cable that includes fiber Bragg gratings routed through the plurality of zones parallel to the first fiber optic cable;
wherein the controller is configured to provide a reference signal to the second fiber optic cable and receive a reference response from the second fiber cable.

3. The system of claim 2 , wherein the controller is configured to determine the at least one temperature in each of the plurality of zones based upon the reference response, the optical response, and coherent optical frequency domain reflectometry (COFDR).

4. The system of claim 1 , wherein the optical transmitter is configured to produce laser pulses with a constant amplitude, and wherein the controller implements Incoherent Optical Frequency Domain Reflectometry (IOFDR) with a step frequency or swept frequency methodology.

5. The system of claim 1 , wherein the controller is configured to control the optical transmitter to provide the optical signal as a single laser pulse at a fixed wavelength, and wherein the controller is configured to determine the at least one temperature of each of the plurality of zones using optical time domain reflectometry (OTDR).

6. The system of claim 1 , wherein the optical transmitter is connected to provide the optical signal to a first end of the first fiber optic cable and the optical receiver is connected to receive the optical response from a second end of the first fiber optic cable, and wherein the system further comprises:
a probe transmitter connected to the second end of the first fiber optic cable and configured to provide a probe signal to the second end of the first fiber optic cable; and
a probe receiver connected to the first end of the first fiber optic cable and configured to receive the probe signal from the first end of the first fiber optic cable;
wherein the controller is configured to determine the at least one temperature of each of the plurality of zones based on a frequency difference between the optical response and the probe response using Brillouin optical time domain analysis (BOTDA).

7. The system of claim 1 , wherein the aircraft system is a bleed air system, and wherein the plurality of zones comprise bleed air ducts.

8. The system of claim 1 , wherein at least one of the plurality of zones comprises a wheel well of the aircraft, and wherein a physical condition of the wheel well is determined by the controller to determine a temperature of a landing gear tire.

9. The system of claim 1 , wherein the threshold value for at least one of the plurality of zones is different than the threshold value for at least one other of the plurality of zones.

10. The system of claim 1 , wherein the controller is configured to detect a sudden increase in temperature indicative of a fire in at least one of the plurality of zones and output indication of a fire event to a cockpit or fire suppression system.

11. A method of detecting thermal conditions for a plurality of zones of an aircraft system, the method comprising:
emitting, by an optical transmitter, an optical signal to a first fiber optic cable that includes fiber Bragg gratings, wherein the first fiber optic cable is routed through each of the plurality of zones of the aircraft system;
receiving, by an optical receiver, a response signal from the first fiber optic cable based upon the optical signal;
determining, using a controller, at least one temperature and/or strain for each of the plurality of zones based upon the response signal; and
indicating a detected condition for detected zones of the plurality of zones in which the at least one temperature and/or strain is greater than a threshold to facilitate preventive maintenance;
wherein the controller is configured to control the optical transmitter and determine the at least one temperature and/or strain for each of the plurality of zones using time division multiplexing (TDM) and/or wavelength division multiplexing (WDM).

12. The method of claim 11 , wherein emitting, by the optical transmitter, the optical signal comprises emitting the optical signal using a tunable, swept-wavelength laser.

13. The method of claim 11 , wherein emitting, by the optical transmitter, the optical signal comprises emitting the optical signal using a broadband laser.

14. The method of claim 11 , wherein emitting, by the optical transmitter, the optical signal comprises emitting laser pulses having a constant amplitude using a step frequency methodology; and wherein determining, using the controller, the at least one temperature for each of the plurality of zones comprises determining the at least one temperature based on optical frequency domain reflectometry (IOFDR).

15. The method of claim 11 , wherein emitting, by the optical transmitter, the optical signal comprises emitting laser pulses having a constant amplitude using a swept frequency methodology; and wherein determining, using the controller, the at least one temperature for each of the plurality of zones comprises determining the at least one temperature based on optical frequency domain reflectometry (IOFDR).

16. The method of claim 11 , further comprising:
providing a reference signal to a second fiber optic cable that includes fiber Bragg gratings routed parallel to the first fiber optic cable through the plurality of zones; and
receiving a reference response from the second fiber cable based on the reference signal;
wherein determining, using the controller, the at least one temperature for each of the plurality of zones comprises determining the at least one temperature based upon the reference response, the optical response, and coherent optical frequency domain reflectometry (COFDR).

17. The method of claim 11 , wherein emitting, by the optical transmitter, the optical signal comprises emitting the optical signal as a single laser pulse at a fixed wavelength, and wherein determining, using the controller, the at least one temperature for each of the plurality of zones comprises determining the at least one temperature for each of the plurality of zones using optical time domain reflectometry (OTDR).

18. The method of claim 11 , wherein emitting, by the optical transmitter, the optical signal comprises emitting the optical signal to a first end of the first fiber optic cable, and wherein receiving, by the optical receiver, the response signal comprises receiving the optical response from a seco

Assignees

• Kidde Tech Inc

Inventors

• Wilson Christopher
• Frasure David William
• Kern Mark Thomas
• Miller Mark Sherwood
• Newlin Scott Kenneth
• Georgoulias Chris George
• Coreth Stefan
• Bell Ken

Classifications

• G01L1/242

  the material being an optical fibre · CPC title

• G01K11/3206 Primary

  at discrete locations in the fibre, e.g. using Bragg scattering · CPC title

• G01K11/32 Primary

  using changes in transmittance, scattering or luminescence in optical fibres · CPC title

• G01K2011/322

  Physics · mapped topic

• G01K11/322

  using Brillouin scattering · CPC title