Optical impedance modulation for fuel quantity measurement comprising a fiber encased by a tube having a longitudinal slot with a lens
First Claim
1. An optical impedance sensor comprising:
- a tube having an internal volume;
a first light guide comprising a first optical fiber and a first tube which encases said first optical fiber, wherein said first tube comprises a first jacket having a longitudinal slot and a first lens disposed in said longitudinal slot of said first jacket and optically coupled to said first optical fiber, and said first optical fiber comprises a cladding having a non-uniform surface in an area bounded by said longitudinal slot of said first jacket; and
a second light guide comprising a second optical fiber spaced apart from said first optical fiber, wherein said second optical fiber comprises a cladding having a non-uniform surface in an area confronting said longitudinal slot of said first jacket.
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Accused Products
Abstract
Systems and methods that use an optical impedance sensor that eliminates electricity for measuring fuel quantity in fuel tanks. The optical impedance sensor comprises two optical fibers spaced apart inside a meniscus tube, one to transmit light along its length and the other to receive light along its length. The meniscus tube minimizes the sloshing of fuel level. The fuel level in the tank modulates the optical impedance between the two optical fibers, resulting in changes in the total light received by an optical detector. Depending on fuel tank height, the optical impedance sensor may comprise different embodiments in which the detection apparatus shapes the light to be unidirectional (emitted and collected only on one side of the fiber) or omnidirectional (all directions).
22 Citations
20 Claims
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1. An optical impedance sensor comprising:
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a tube having an internal volume; a first light guide comprising a first optical fiber and a first tube which encases said first optical fiber, wherein said first tube comprises a first jacket having a longitudinal slot and a first lens disposed in said longitudinal slot of said first jacket and optically coupled to said first optical fiber, and said first optical fiber comprises a cladding having a non-uniform surface in an area bounded by said longitudinal slot of said first jacket; and a second light guide comprising a second optical fiber spaced apart from said first optical fiber, wherein said second optical fiber comprises a cladding having a non-uniform surface in an area confronting said longitudinal slot of said first jacket. - View Dependent Claims (2, 3, 4, 5)
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6. A system for measuring a level of liquid in a reservoir, comprising:
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a tube having an internal volume, said tube being disposed in the reservoir; an optical source for outputting light; an optical detector for converting impinging light into an electrical signal representing an optical power of the impinging light; a first light guide comprising a first optical fiber and a first tube which encases said first optical fiber, wherein said first tube comprises a first jacket having a longitudinal slot and a first lens disposed in said longitudinal slot of said first jacket and optically coupled to said first optical fiber, and said first optical fiber comprises a cladding and a core inside said cladding, said cladding of said first optical fiber having a non-uniform surface in an area bounded by said longitudinal slot of said first jacket, and said core of said first optical fiber being optically coupled to receive light from said optical source; and a second light guide comprising a second optical fiber spaced apart from said first optical fiber, wherein said second optical fiber comprises a cladding and a core inside said cladding, said cladding of said second optical fiber having a non-uniform surface which receives light emitted by said first optical fiber through said longitudinal slot of said first jacket, and said core of said second optical fiber being optically coupled to output light to said optical detector. - View Dependent Claims (7, 8, 9, 10, 11, 12, 13)
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14. A light guide comprising:
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an optical fiber having an axis and a circumferential surface; a jacket having a longitudinal slot that extends parallel to said axis of said optical fiber, said jacket being in contact with said circumferential surface of said optical fiber except in an area of said longitudinal slot; and a lens disposed in said longitudinal slot of said jacket and interfaced with said circumferential surface of said optical fiber, wherein said optical fiber comprises a cladding having a non-uniform surface in an area bounded by said longitudinal slot of said jacket. - View Dependent Claims (15, 16)
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17. A method for measuring a level of fuel in a fuel tank having multiple compartments, comprising:
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placing a first tube in a first compartment; placing a first light guide inside the first tube with an orientation that will be generally perpendicular to a surface of the fuel when the first compartment is at least partially filled with fuel, wherein the first light guide comprises a first optical fiber that is encased to prevent wetting of the first optical fiber when the first light guide is immersed in the fuel; placing a second light guide inside the first tube spaced apart from and generally parallel with the first light guide, wherein the second light guide comprises a second optical fiber that is encased to prevent wetting of the second optical fiber when the second light guide is immersed in the fuel; emitting light along a length of the first light guide toward a length of the second light guide; detecting the optical power output from the second light guide; and determining a level of the fuel in the first compartment based on the detected optical power output from the second light guide. - View Dependent Claims (18, 19, 20)
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Specification