Systems and methods for determining a fuel level measurement of a fuel tank using optical sensor

Patent metadata

Field	Value
Publication number	US-10126158-B2
Application number	US-201615243062-A
Country	US
Kind code	B2
Filing date	Aug 22, 2016
Priority date	Aug 22, 2016
Publication date	Nov 13, 2018
Grant date	Nov 13, 2018

Abstract

An example fuel quantity indicating system includes a fuel tank, optical sensors mounted inside the fuel tank that each include a sensor chip and a diaphragm that deflects when ambient pressure differs from a reference pressure of the sensor chip, an optical fiber bundle that has an optical fiber connected to each of the optical sensors for guiding light to each of the optical sensors, and a processor connected to the optical fiber bundle for receiving outputs of the optical sensors indicative of respective pressures, and for determining a fuel level measurement of the fuel tank based on the outputs of the optical sensors.

First claim

What is claimed is:

1. A system comprising:
a fuel tank;
a plurality of optical sensors mounted inside the fuel tank, wherein the plurality of optical sensors each include a sensor chip and a diaphragm that deflects when ambient pressure differs from a reference pressure of the sensor chip, wherein respective positions of the plurality of optical sensors inside the fuel tank are represented by a height above a bottom of the fuel tank;
an optical fiber bundle having an optical fiber connected to each of the plurality of optical sensors for guiding light to each of the plurality of optical sensors; and
one or more processors connected to the optical fiber bundle for receiving outputs of the plurality of optical sensors indicative of respective pressures, and for determining a height of fuel in the fuel tank based on a ratio of a difference of pressures indicated by outputs of a first optical sensor and a second optical sensor and a specific gravity of fuel included in the fuel tank, wherein the one or more processors further determine a fuel level measurement of the fuel tank based on the height of fuel in the fuel tank.

2. The system of claim 1 , wherein the fuel tank has a top, the bottom, and sides, and wherein respective sensors of the plurality of optical sensors are at least positioned on a side and the bottom.

3. The system of claim 1 , wherein as the plurality of optical sensors are submerged in fuel in the fuel tank, the outputs of the plurality of optical sensors change.

4. The system of claim 1 , wherein the optical fiber bundle enters the fuel tank at one location and is positioned inside the fuel tank and terminates with respective optical fibers at respective positions of the plurality of optical sensors.

5. The system of claim 1 , wherein the outputs of the plurality of optical sensors include reflected light off of respective diaphragms, and wherein the one or more processors determine a respective pressure based on the reflected light.

6. The system of claim 1 , wherein the fuel level measurement includes a volume of fuel in the fuel tank.

7. The system of claim 1 , wherein the plurality of optical sensors further provide outputs for determination of a temperature inside the fuel tank.

8. The system of claim 1 , further comprising a light source coupled to the optical fiber bundle for generating the light.

9. The system of claim 1 , wherein the one or more processors determine the specific gravity of fuel included in the fuel tank based on a temperature inside the fuel tank and reference to a density/temperature graph.

10. The system of claim 1 , wherein the one or more processors determine the specific gravity of fuel included in the fuel tank based on (i) a difference between outputs of two sensors of the plurality of optical sensors for determination of a difference in weight of fuel, and (ii) a known distance between the two sensors for calculation of a weight per unit volume of the fuel.

11. The system of claim 1 , wherein the one or more processors further receive information related to one or more of a roll, a pitch, and a yaw of the fuel tank, and
wherein the one or more processors determine the height of fuel in the fuel tank based also on an angle of tilt of the fuel tank determined from the information related to one or more of the roll, the pitch, and the yaw of the fuel tank.

12. The system of claim 1 , wherein the one or more processors determine the height of fuel in the fuel tank at a position of each of the plurality of optical sensors based on the respective pressures and on an angle of tilt of the fuel tank, and
wherein the one or more processors determine the fuel level measurement of the fuel tank based on a sum of a volume of fuel as determined due to the height for each of the plurality of optical sensors.

13. An aircraft comprising:
a fuel tank positioned in one or more of a wing and a fuselage of the aircraft;
a plurality of optical sensors mounted inside the fuel tank, wherein the plurality of optical sensors each include a sensor chip and a diaphragm that deflects when ambient pressure differs from a reference pressure of the sensor chip, wherein respective positions of the plurality of optical sensors inside the fuel tank are represented by a height above a bottom of the fuel tank;
an optical fiber bundle having an optical fiber connected to each of the plurality of optical sensors for guiding light to each of the plurality of optical sensors; and
one or more processors connected to the optical fiber bundle for receiving outputs of the plurality of optical sensors indicative of respective pressures, and for determining a height of fuel in the fuel tank based on a ratio of a difference of pressures indicated by outputs of a first optical sensor and a second optical sensor and a specific gravity of fuel included in the fuel tank, wherein the one or more processors further determine a fuel level measurement of the fuel tank based on the height of fuel in the fuel tank and accounting for any deflections of the wing and flight dynamics.

14. The aircraft of claim 13 , further comprising a light source coupled to the optical fiber bundle for generating the light.

15. The aircraft of claim 13 , wherein the one or more processors determine the height of fuel in the fuel tank at a position of each of the plurality of optical sensors based on the respective pressures and on an angle of tilt of the fuel tank due to the flight dynamics, and
wherein the one or more processors determine the fuel level measurement of the fuel tank based on a sum of a volume of fuel as determined due to the height for each of the plurality of optical sensors.

16. The aircraft of claim 13 , wherein the one or more processors determine the specific gravity of fuel included in the fuel tank based on a temperature inside the fuel tank and reference to a density/temperature graph.

17. The aircraft of claim 13 , wherein the one or more processors determine the specific gravity of fuel included in the fuel tank based on (i) a difference between outputs of two sensors of the plurality of optical sensors for determination of a difference in weight of fuel, and (ii) a known distance between the two sensors for calculation of a weight per unit volume of the fuel.

18. The aircraft of claim 13 , wherein the one or more processors further receive information related to one or more of a roll, a pitch, and a yaw of the fuel tank, and
wherein the one or more processors determine the height of fuel in the fuel tank based also on an angle of tilt of the fuel tank determined from the information related to one or more of the roll, the pitch, and the yaw of the fuel tank.

19. A method for determining a fuel level measurement of a fuel tank, comprising:
receiving, from a plurality of optical sensors mounted inside a fuel tank, outputs indicative of respective pressures, wherein the plurality of optical sensors each include a sensor chip and a diaphragm that deflects when ambient pressure differs from a reference pressure of the sensor chip, wherein respective positions of the plurality of optical sensors inside the fuel tank are represented by a height above a bottom of the fuel tank;
determining a height of fuel in the fuel tank based on a ratio of a difference of pressures indicated by outputs of a first optical sensor and a second optical sensor, and a specific gravity of fuel included in the fuel tank; and
determining, by one or more processors, a fuel level measurement of the fuel tank based on the height of fuel in the fuel tank.

Assignees

• Boeing Co

Inventors

• Carralero Michael A
• Kasim Kawthar
• Truzzi Paul Scott

Classifications

• G01F23/292 Primary

  Light {, e.g. infrared or ultraviolet} · CPC title

• G01F23/18

  Indicating, recording or alarm devices actuated electrically · CPC title

• G01F23/14 Primary

  by measurement of pressure · CPC title

• B64D37/005

  Accessories not provided for in the groups B64D37/02 - B64D37/28 · CPC title

• B64D37/02

  Tanks (tanks constructed integrally with aircraft wings B64C3/34) · CPC title