Catalytic fuel tank inerting systems for aircraft

Patent metadata

Field	Value
Publication number	US-11155358-B2
Application number	US-201916372943-A
Country	US
Kind code	B2
Filing date	Apr 2, 2019
Priority date	Apr 2, 2019
Publication date	Oct 26, 2021
Grant date	Oct 26, 2021

Abstract

Fuel tank inerting systems and methods for aircraft are described. The systems and methods include controlling of (i) a first reactant control element, (ii) a second reactant control valve, (iii) a ram air control valve, (iv) a driving mechanism, and (v) a flow control valve, to control a state of a fuel tank inerting system. The states of the fuel tank inerting system include an OFF state, a CIRCULATE state, a PRIME state, a CATWARM state, an ON state, a DEPRESSURIZE state, and a COOLDOWN state, wherein the states are determined in part by a prior state and/or a position/actuation of a given element of the system.

First claim

What is claimed is:

1. A fuel tank inerting system for an aircraft, the system comprising:
a fuel tank;
a first reactant source fluidly connected to the fuel tank, the first reactant source arranged to receive fuel from the fuel tank, the first reactant source having a first reactant control element controlling flow thereof;
a second reactant source having a second reactant control valve controlling flow thereof;
a catalytic reactor arranged to receive a first reactant from the first reactant source and a second reactant from the second reactant source to generate an inert gas to be supplied to the fuel tank to fill an ullage space of the fuel tank;
a heat exchanger arranged between the catalytic reactor and the fuel tank and configured to at least one of cool and condense an output from the catalytic reactor to separate out the inert gas;
a ram air control valve configured to control flow of ram air into the heat exchanger;
a recirculation loop having a driving mechanism therein, configured to drive a flow of gas through the fuel tank inerting system;
a flow control valve arranged between the catalytic reactor and the ullage space, the flow control valve configured to control a flow of inert gas into the ullage space; and
a controller configured to control operation of (i) the first reactant control element, (ii) the second reactant control valve, (iii) the ram air control valve, (iv) the driving mechanism, and (v) the flow control valve, the controller configured to control a state of the fuel tank inerting system, wherein states of the fuel tank inerting system comprise at least an OFF state, wherein, in the OFF state, the second reactant control valve is fully closed, the ram air control valve is fully open, the driving mechanism is off, the flow control valve is fully closed, and the first reactant control element is off.

2. The system of claim 1 , further comprising a recirculation heat exchanger arranged within the recirculation loop and configured to thermally connect a flow through the recirculation loop and a flow exiting the catalytic reactor.

3. The system of claim 1 , wherein the states of the fuel tank inerting system further include a CIRCULATE state where the second reactant control valve is fully closed, the ram air control valve is fully open, the driving mechanism is on, the flow control valve is fully closed, and the first reactant control element off.

4. The system of claim 3 , wherein operation of the driving mechanism causes a temperature within the fuel tank inerting system to increase.

5. The system of claim 4 , wherein the temperature increase is caused by waste heat generated by the driving mechanism.

6. The system of claim 1 , wherein the states of the fuel tank inerting system further include a PRIME state where the second reactant control valve is fully closed, the ram air control valve is modulated to cause a temperature at an inlet of the catalytic reactor to reach a lightoff temperature, the driving mechanism is on, the flow control valve is fully closed, and the first reactant control element is off.

7. The system of claim 1 , wherein the states of the fuel tank inerting system further include a CATWARM state where the second reactant control valve is fully closed, the ram air control valve is modulated to cause a temperature at an inlet of the catalytic reactor to reach a lightoff temperature, the driving mechanism is on, the flow control valve is fully closed, and the first reactant control element is off.

8. The system of claim 7 , wherein a temperature at an outlet of the catalytic reactor is monitored for a predetermined period of time.

9. The system of claim 1 , wherein the states of the fuel tank inerting system further include an ON state where the second reactant control valve is fully open, the ram air control valve is open, the driving mechanism is on, the flow control valve is open, and the first reactant control element is operated to supply fuel to the catalytic reactor.

10. The system of claim 1 , wherein the states of the fuel tank inerting system further include a DEPRESSURIZE state where the second reactant control valve is fully closed, the ram air control valve is open, the driving mechanism is on, the flow control valve is open, and the first reactant control element is off.

11. The system of claim 1 , wherein the states of the fuel tank inerting system further include a COOLDOWN state where the second reactant control valve is fully closed, the ram air control valve is fully open, the driving mechanism is on, the flow control valve is fully closed, and the first reactant control element is off.

12. A method of controlling operation of a fuel tank inerting system of an aircraft, the method comprising:
controlling a state of (i) a first reactant control element, (ii) a second reactant control valve, (iii) a ram air control valve, (iv) a driving mechanism, and (v) a flow control valve to control a state of the fuel tank inerting system, wherein states of the fuel tank inerting system comprise at least an OFF state where the second reactant control valve is fully closed, the ram air control valve is fully open, the driving mechanism is off, the flow control valve is fully closed, and the first reactant control element is off.

13. The method of claim 12 , wherein the states of the fuel tank inerting system further include a CIRCULATE state where the second reactant control valve is fully closed, the ram air control valve is fully open, the driving mechanism is on, the flow control valve is fully closed, and the first reactant control element off.

14. The method of claim 12 , wherein the states of the fuel tank inerting system further include a PRIME state where the second reactant control valve is fully closed, the ram air control valve is modulated to cause a temperature at an inlet of a catalytic reactor to reach a lightoff temperature, the driving mechanism is on, the flow control valve is fully closed, and the first reactant control element is off.

15. The method of claim 12 , wherein the states of the fuel tank inerting system further include a CATWARM state where the second reactant control valve is fully closed, the ram air control valve is modulated to cause a temperature at an inlet of a catalytic reactor to reach a lightoff temperature, the driving mechanism is on, the flow control valve is fully closed, and the first reactant control element is off.

16. The method of claim 12 , wherein the states of the fuel tank inerting system further include an ON state where the second reactant control valve is fully open, the ram air control valve is open, the driving mechanism is on, the flow control valve is open, and the first reactant control element is operated to supply fuel to a catalytic reactor.

17. The method of claim 12 , wherein the states of the fuel tank inerting system further include a DEPRESSURIZE state where the second reactant control valve is fully closed, the ram air control valve is open, the driving mechanism is on, the flow control valve is open, and the first reactant control element is off.

18. The method of claim 12 , wherein the states of the fuel tank inerting system further include a COOLDOWN state where the second reactant control valve is fully closed, the ram air control valve is fully open, the driving mechanism is on, the flow control valve is fully closed, and the first reactant control element is off.

19. A method of controlling operation of a fuel tank inerting system of an aircraft, the method comprising:
controlling a state of (i) a first reactant control

Assignees

• Hamilton Sundstrand Corp

Inventors

• Lavallee Iii Earl Jean
• Surawski Eric

Classifications

• Y02T50/40

  Weight reduction · CPC title

• B64D37/32 Primary

  Safety measures not otherwise provided for, e.g. preventing explosive conditions · CPC title

• B64D37/10 Primary

  to facilitate fuel pressurisation · CPC title

• B64D37/24

  using gas pressure · CPC title

• B64D37/34

  Conditioning fuel, e.g. heating (during filling B64D37/18) · CPC title