Early coking detection in aircraft fuel

1. A method for early detection of coking in aircraft fuel in a fuel system, the method comprising:

generating an excitation signal for a contamination detection sensor having an input transducer and an output transducer immersed in the aircraft fuel;

receiving at a controller operably connected to the contamination detection sensor a sensor output signal from the output transducer;

comparing the sensor output signal with the excitation signal;

diagnosing a condition of the fuel based on a the comparing; and

indicating a condition of coking based on the diagnosing,

wherein the diagnosing includes at least one of collecting data over time to facilitate making lifetime predictions of fuel system component, and identifying coking only after a predetermined threshold of coking has been exceeded.

2. The method of claim 1 , wherein the generating includes providing an alternating current (AC) signal to the contamination detection sensor.

3. The method of claim 2 , wherein the alternating current (AC) signal is at least one of a sinusoid and exhibits a frequency corresponding to the synchronous frequency of the contamination detection sensor to minimize insertion loss.

4. The method of claim 1 , wherein the contamination detection sensor is at least one of a surface acoustic wave sensor, a horizontal shear acoustic wave sensor, and a thickness shear mode sensor.

5. The method of claim 1 , wherein the sensor output signal exhibits at least one of a delay, a phase shift, a frequency shift based on a presence of particulates in the aircraft fuel.

6. The method of claim 5 , wherein the at least one of a delay, a phase shift, and a frequency shift is proportional to the mass of a particle or film deposited on the sensor in the aircraft fuel.

7. The method of claim 1 , wherein the identifying includes latching an indication of detected coking and notifying a ground maintenance to conduct and inspection of the fuel system.

8. The method of claim 1 , wherein the fuel system includes at least one of sensors, valves, tubing nozzles, and injectors.

9. A system for early detection of coking in aircraft fuel, the system comprising:

a fuel system for delivery of fuel to a component;

a fuel contamination sensor, the fuel contamination sensor comprising a contamination detection sensor having an input transducer and an output transducer immersed in the aircraft fuel;

a controller in operable communication with the fuel contamination sensor, the controller configured to execute a method for early detection of coking in the aircraft fuel, the method comprising:

generating an excitation signal for the contamination detection sensor;

receiving at a controller operably connected to the contamination detection sensor a sensor output signal from the output transducer;

comparing the sensor output signal with the excitation signal;

diagnosing a condition of the fuel based on a the comparing;

indicating a condition of coking based on the diagnosing; and

an enunciator to indicate the detection of coking,

wherein the diagnosing includes at least one of collecting data over time to facilitate making lifetime predictions of fuel system component, and identifying coking only after a predetermined threshold of coking has been exceeded.

10. The system of claim 9 , wherein the excitation signal is an alternating current (AC) signal to the contamination detection sensor.

11. The system of claim 10 , wherein the alternating current (AC) signal is at least one of a sinusoid and exhibits a frequency corresponding to the synchronous frequency of the contamination detection sensor to minimize insertion loss.

12. The system of claim 9 , wherein the contamination detection sensor is at least one of a surface acoustic wave sensor, a horizontal shear acoustic wave sensor, and a thickness shear mode sensor.

13. The system of claim 9 , wherein the sensor output signal exhibits at least one of a delay, a phase shift, a frequency shift based on a presence of at least one of particulates and film disposed on the contamination detection sensor in the aircraft fuel.

14. The system of claim 9 , wherein the output signal of the sensor exhibits at least one of a delay, a phase shift, and a frequency shift proportional to the mass of a particle or film deposited on the sensor in the aircraft fuel.

15. The system of claim 9 , wherein the identifying includes latching an indication of detected coking and generating a notification to conduct and inspection of the fuel system.

16. The system of claim 9 , wherein the fuel system components include at least one of sensors, valves, tubing nozzles, and injectors.

17. The system of claim 9 , wherein at least a portion of the fuel system is used as a heat sink.

18. The system of claim 9 , wherein the fuel system is part of a gas turbine engine.

19. A system for early detection of coking in aircraft fuel, the system comprising:

a fuel system for delivery of fuel to a component;

a fuel contamination sensor, the fuel contamination sensor comprising a contamination detection sensor having an input transducer and an output transducer immersed in the aircraft fuel;

a controller in operable communication with the fuel contamination sensor, the controller configured to execute a method for early detection of coking in the aircraft fuel, the method comprising:

generating an excitation signal for the contamination detection sensor;

receiving at a controller operably connected to the contamination detection sensor a sensor output signal from the output transducer;

comparing the sensor output signal with the excitation signal;

diagnosing a condition of the fuel based on a the comparing;

indicating a condition of coking based on the diagnosing; and

an enunciator to indicate the detection of coking,

wherein the identifying includes latching an indication of detected coking and generating a notification to conduct and inspection of the fuel system.