Capacitor Emulator for Aircraft Fuel Sensor Validation

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Solution Overview

Problem

Existing validation methods for capacitance measurement devices in aircraft fuel systems are time-consuming and hazardous, requiring repeated emptying and filling of fuel tanks to test various fuel levels.

Innovation Solution

A capacitance validation system that uses a capacitor emulator to simulate variable capacitance, allowing for faster and safer validation of capacitance measurement devices by negating stray capacitances and using a controller to modify drive signals.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If conventional validation methods using actual fuel tanks are used, then measurement accuracy can be validated, but the testing process becomes time-consuming and hazardous

Engineering Contradiction:
Improvevalidation accuracyVSAvoidtesting time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The patent creates an electrical copy of the fuel tank system using a capacitor emulator that replicates the capacitive characteristics of actual fuel levels. The emulator generates capacitance values corresponding to different fuel levels (0-100%) without requiring physical fuel, thus validating the measurement device quickly and safely while maintaining validation accuracy.

Inventive Principle:
Principle #26Copying

Solution Approach 2:

The patent replaces the mechanical/physical system of actual fuel tanks and liquid fuel with an electrical system using capacitors and electronic signal generation. The capacitor emulator uses electrical components (capacitors, resistors, operational amplifiers) to simulate the capacitive effect of fuel levels, eliminating the need for physical fuel handling while preserving measurement validation capability.

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

2Measurement precision

If conventional validation methods using actual fuel tanks are used, then measurement accuracy can be validated, but safety hazards increase

Engineering Contradiction:
Improvevalidation accuracyVSAvoidsafety hazards
Core Design Contradiction:
Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The patent creates an electrical copy of the fuel tank system using a capacitor emulator that replicates the capacitive characteristics of actual fuel levels. The emulator generates capacitance values corresponding to different fuel levels (0-100%) without requiring physical fuel, thus validating the measurement device quickly and safely while maintaining validation accuracy.

Inventive Principle:
Principle #26Copying

Solution Approach 2:

The patent replaces the mechanical/physical system of actual fuel tanks and liquid fuel with an electrical system using capacitors and electronic signal generation. The capacitor emulator uses electrical components (capacitors, resistors, operational amplifiers) to simulate the capacitive effect of fuel levels, eliminating the need for physical fuel handling while preserving measurement validation capability.

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

3Productivity

If capacitor emulator is used to simulate variable capacitance, then testing speed improves, but device complexity increases

Engineering Contradiction:
Improvetesting speedVSAvoidvalidation system complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent divides the validation system into distinct functional modules: a capacitor emulator module that generates capacitance signals, a signal conditioning module with operational amplifiers and resistors, and a validation processing module. This segmentation allows each component to perform a specific function, making the overall complex system manageable and maintainable while achieving fast testing speeds.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces intermediate components such as operational amplifiers (op-amps), resistors, and capacitors that mediate between the capacitor emulator and the measurement device under test. These intermediaries condition and transfer signals in a controlled manner, enabling the complex validation function to be achieved through manageable intermediate steps rather than a single complex operation.

Inventive Principle:
Principle #24Intermediary (Mediator)

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

Enables rapid and safe validation of capacitance measurement devices by simulating various fuel levels without physically changing the fuel level, thus reducing testing time and hazards.

Implementation Method 1

a capacitor emulator to simulate variable capacitance

Methodology Applied
Scientific EffectCapacitance: Capacitance

Implementation Method 2

capacitor emulator to simulate variable capacitance

Methodology Applied
Scientific EffectElectrical charge storage: Electrical Accumulator

Data Source

PatentEP4095494B1Method and apparatus for validating a capacitive fuel level sensor
Publication Date: 2025.04.23 SIMMONDS PRECISION PRODUCTS INC
  • EP4095494B1 patent drawingFigure 1

AI summary

A method for validating a capacitance measurement device including, sending a first drive signal from a capacitance measurement device to a capacitor emulator, modifying the first drive signal by an four quadrant analog multiplier, directing the modified signal across a capacitor to produce a return signal, sending the return signal to the capacitance measurement device to validate the capacitor, and validating the return signal against an expected return signal by the capacitance measurement device.