Wireless Fuel Sensor System Using Capacitive Probes

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Solution Overview

Problem

The use of wired sensor systems in aircraft fuel tanks is time-consuming and costly, adding weight and increasing maintenance complexity due to the need for routing wires and forming openings, which also poses challenges with electromagnetic interference.

Innovation Solution

A wireless sensor system that uses capacitive probes and radio frequency signals to measure fuel levels, eliminating the need for physical wires and reducing the number of openings required, with a sensor controller sending power and data signals wirelessly to sensor units within the fuel tank.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If wired sensor systems are used in fuel tanks, then reliable data transmission can be achieved, but installation time and cost increase due to wire routing and opening formation

Engineering Contradiction:
Improvedata transmission reliabilityVSAvoidinstallation time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The patent extracts the transmission medium (wires) from the sensor system by implementing wireless communication between sensor units and the external system. This eliminates the need for physical wire routing through the fuel tank, thereby reducing installation time and complexity while maintaining data transmission reliability through radio frequency signals.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent replaces the mechanical wire-based connection system with an electromagnetic field-based wireless communication system. This substitution eliminates the need for physical openings in the fuel tank and complex wire routing, significantly reducing installation time and cost while maintaining reliable data transmission.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Use of energy by moving object

If wired sensor systems are used in fuel tanks, then stable power supply can be ensured, but aircraft weight increases due to additional wire structures and protective components

Engineering Contradiction:
Improvepower supply stabilityVSAvoidaircraft weight
Core Design Contradiction:
Use of energy by moving objectVSWeight of moving object

Solution Approach 1:

The patent removes the power transmission medium (wires) from the system by implementing wireless power transmission through electromagnetic fields. This eliminates the need for heavy wire structures, protective conduits, and associated mounting hardware, thereby reducing aircraft weight while maintaining power supply stability.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent substitutes the mechanical wire-based power transmission system with an electromagnetic field-based wireless power transmission system. This replacement eliminates the weight of physical power transmission infrastructure while maintaining stable power delivery to sensor units through RF energy transfer.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Ease of manufacture

If multiple wire openings are formed in fuel tanks, then sensor installation is enabled, but maintenance complexity and cost increase due to seal inspections and wire integrity checks

Engineering Contradiction:
Improvesensor installation easeVSAvoidmaintenance complexity
Core Design Contradiction:
Ease of manufactureVSEase of repair

Solution Approach 1:

The patent extracts the physical connection infrastructure (wires and openings) from the sensor installation system by implementing wireless communication. This eliminates the need for forming openings in fuel tanks and installing wire routing structures, thereby simplifying both installation and maintenance processes while reducing the number of components requiring inspection.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent replaces the mechanical wire-based connection system with wireless electromagnetic communication. This substitution eliminates the need for physical openings in fuel tanks and complex wire routing, significantly reducing maintenance complexity by removing seal inspections and wire integrity checks from the maintenance regimen.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

4Reliability

If wires are routed through aircraft wings and fuselage, then sensor connectivity is achieved, but electromagnetic interference from environmental effects increases

Engineering Contradiction:
Improvesensor connectivityVSAvoidelectromagnetic interference
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent substitutes the wire-based electrical connection system with wireless electromagnetic communication. This replacement eliminates the wires that act as antennas for electromagnetic interference from lightning and static electricity, thereby reducing the harmful effects of electromagnetic interference on sensor connectivity while maintaining reliable wireless communication.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This solution reduces installation time and cost, minimizes weight, and enhances aircraft performance by eliminating wire-related issues, while also reducing maintenance complexity and electromagnetic interference concerns.

Implementation Method 1

a measurement corresponding to a fuel level within a fuel tank is determined based on a capacitance between the first conductor and the second conductor

Methodology Applied
Scientific EffectCapacitance: Capacitance

Implementation Method 2

a radio frequency signal conveying the data is transmitted wirelessly from the sensor unit to the sensor controller

Methodology Applied
Scientific EffectRadio frequency electromagnetic radiation: Electromagnetic Induction

Data Source

PatentEP2982943B1Wireless fuel sensor system
Publication Date: 2019.11.13 THE BOEING CO
  • EP2982943B1 patent drawingFigure 1
  • EP2982943B1 patent drawingFigure 2
  • EP2982943B1 patent drawingFigure 3~5

AI summary

A sensor device includes a capacitive probe including a first conductor and a second conductor. The sensor device also includes a radio to generate a signal based on a measurement associated with the capacitive probe and to provide the signal to the first conductor for transmission using the capacitive probe as a transmission antenna.