Multi-Sensor Fuel Gauging Probe Eliminates Tank Perforation

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Solution Overview

Problem

Existing fuel gauging systems in aeronautics require complex installations that involve perforating aircraft tanks, leading to potential leakage, increased weight, and maintenance complications, and are sensitive to fuel quality and contamination, necessitating multiple sensor types.

Innovation Solution

A multi-sensor measuring device integrating at least one pressure sensor, one density sensor, and optionally a permittivity sensor, with microelectromechanical sensors (MEMS) that can be easily integrated into existing systems without puncturing the tank, using a modular design with quick fastening mechanisms and embedded connections to ensure secure and leak-proof installation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If capacitive probes are used for fuel measurement, then the measurement can be obtained, but the measurement accuracy deteriorates due to fuel quality and water contamination variations in dielectric constant

Engineering Contradiction:
Improvefuel level measurement accuracyVSAvoidmeasurement reliability under varying fuel conditions
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The patent combines multiple sensing technologies (capacitive probe, MFLI magnetic sensor, pressure sensor, density sensor) into a single integrated measuring device. This merging allows the system to compensate for the limitations of individual sensors by using their complementary strengths, thereby maintaining measurement accuracy across varying fuel conditions without requiring separate installation systems.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The integrated measuring device performs multiple functions simultaneously: it measures fuel level (capacitive), detects water presence (MFLI magnetic sensor), monitors pressure, and measures density. This multi-functionality eliminates the need for separate specialized sensors for each parameter, providing comprehensive fuel monitoring while improving reliability under varying fuel quality conditions.

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Reliability

If multiple sensors and MFLI probes are installed to compensate for measurement errors, then the measurement reliability is improved, but the installation complexity and weight increase due to drilling holes and adding reinforcements

Engineering Contradiction:
Improvemeasurement reliabilityVSAvoidinstallation complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent integrates multiple sensors (capacitive probe, MFLI magnetic sensor, pressure sensor, density sensor) into a single combined measuring device that can be installed through one access point. This eliminates the need for multiple separate installations, drilling multiple holes, and adding multiple reinforcement points, thereby reducing installation complexity while maintaining the reliability benefits of multi-parameter sensing.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The universal measuring device performs multiple measurement functions (level, water detection, pressure, density) through a single integrated unit. This multi-functionality reduces the overall number of components that need to be installed and secured, simplifying the installation process while ensuring reliable measurements across all parameters.

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Reliability

If multiple sensors and MFLI probes are installed to compensate for measurement errors, then the measurement reliability is improved, but the aircraft weight increases due to additional reinforcements around drilled holes

Engineering Contradiction:
Improvemeasurement reliabilityVSAvoidaircraft weight
Core Design Contradiction:
ReliabilityVSWeight of moving object

Solution Approach 1:

The patent combines multiple sensing functions into a single measuring device that requires only one installation point in the fuel tank. This eliminates the need for multiple separate probe installations and their associated reinforcement structures, thereby reducing the total weight added to the aircraft while maintaining measurement reliability through integrated multi-parameter sensing.

Inventive Principle:
Principle #5Merging (Combining)

4Device complexity

If capacitive probes are used, then the structure is simple, but the system requires watertight assembly which introduces leakage risks and complicates maintenance

Engineering Contradiction:
Improveprobe structure simplicityVSAvoidleakage risk
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The integrated measuring device is designed as a removable unit that can be easily extracted from the fuel tank through the existing filler aperture. This allows for simple replacement and maintenance without requiring complex disassembly of watertight connections, eliminating leakage risks associated with permanent installations while maintaining structural simplicity.

Inventive Principle:
Principle #34Discarding and recovering

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

The solution provides a reliable, easy-to-install, and maintain fuel gauging system that eliminates the need for secondary probes, reduces weight, and minimizes leakage risks while ensuring accurate measurements through integrated MEMS sensors, enhancing the overall efficiency and safety of fuel management.

Implementation Method 1

at least one pressure sensor

Methodology Applied
Scientific EffectPressure measurement:

Implementation Method 2

one density sensor

Methodology Applied
Scientific EffectDensity measurement:

Implementation Method 3

at least one permittivity sensor

Methodology Applied
Scientific EffectPermittivity measurement: Dielectric Permittivity

Implementation Method 4

The capacitance of the capacitor formed by the two electrodes depends linearly on the height of the fuel column between the two tubes

Methodology Applied
Scientific EffectCapacitance measurement: Capacitance

Implementation Method 5

a magnet attached to a float, with the magnet moving relative to magnetic flux sensors as a function of the fuel level

Methodology Applied
Scientific EffectMagnetic flux detection: Magnetic Field

Data Source

PatentEP2064530B1Multiple-sensor measuring device for on-board gauging probe
Publication Date: 2020.02.26 AIRBUS (SAS)
  • EP2064530B1 patent drawingFigure 1
  • EP2064530B1 patent drawingFigure 2
  • EP2064530B1 patent drawingFigure 3~4

AI summary

The present invention relates to a multiple-sensor device for a gauging system comprising: an insert (160) to be inserted along an axis into a capacitive probe (100) so as to assume a predetermined axial position relative to said probe; a support (200) on which a plurality of sensors (210) is mounted; and retaining means (180, 185, 190, 195) for maintaining said support at a predetermined distance of said insert along said axis.