Tire Pressure Measurement Using a Temperature-Balanced Reference Gas

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Solution Overview

Problem

Current tire pressure measurement systems for aircraft require temperature correction, which complicates on-board systems and extends maintenance operations, as the pressure measurement is sensitive to gas temperature and external conditions.

Innovation Solution

The equipment measures tire inflation pressure by bringing the reference gas and inflation gas to identical temperatures, allowing the opposing pressures to compensate each other, thus eliminating the need for temperature correction, using a piston and linear displacement sensor to determine pressure from the piston's position.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If temperature correction is applied to pressure measurement, then measurement precision is improved, but device complexity increases

Engineering Contradiction:
Improvepressure measurement accuracyVSAvoidsystem complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The invention changes the reference parameter from a fixed reference pressure to a reference pressure that varies with temperature. By using a reference gas chamber whose pressure changes with temperature, the system automatically compensates for temperature effects without requiring complex correction algorithms or additional sensors.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The reference gas chamber acts as an intermediary that mediates between the temperature environment and the measurement system. It translates temperature variations into corresponding pressure variations that automatically compensate for thermal effects on the measurement, eliminating the need for direct temperature measurement and correction calculations.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Measurement precision

If temperature correction is applied to pressure measurement, then measurement precision is improved, but maintenance time increases

Engineering Contradiction:
Improvepressure measurement accuracyVSAvoidmaintenance time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The measurement system performs self-correction for temperature effects through the reference gas chamber. The system automatically compensates for temperature variations without requiring external intervention, calibration adjustments, or maintenance personnel to perform correction procedures, thereby reducing maintenance time and operational complexity.

Inventive Principle:
Principle #25Self-service

3Reliability

If a conduit is used to connect tire to pressure sensor, then measurement reliability is improved, but the measurement process becomes more complex

Engineering Contradiction:
Improvemeasurement reliabilityVSAvoidmeasurement process complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The invention merges the reference gas chamber with the measurement chamber in a single integrated body. Both chambers share the same physical space and are subjected to the same temperature conditions, eliminating the need for separate temperature measurement systems and simplifying the overall measurement process while maintaining reliable pressure differential measurement.

Inventive Principle:
Principle #5Merging (Combining)

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 allows for accurate and temperature-independent tire pressure measurement, simplifying the process and reducing maintenance time by directly correlating the piston's position with the tire pressure without requiring temperature adjustments.

Implementation Method 1

The piston (25) responds to pressure differences between the reference gas and the inflation gas by moving to a new position

Methodology Applied
Scientific EffectPressure difference: Pressure Gradient

Implementation Method 2

The equipment uses a piston and linear displacement sensor to determine pressure from the piston's position

Methodology Applied
Scientific EffectLinear displacement detection: Displacement

Data Source

PatentEP2703798B1Equipment for measuring the inflation pressure of a tire of a vehicle wheel
Publication Date: 2024.03.13 SAFRAN LANDING SYSTEMS
  • EP2703798B1 patent drawingFigure 1~2b
  • EP2703798B1 patent drawingFigure 3a~5

AI summary

The equipment has a communication opening (19) for putting an internal volume of a body (16) into communication with an inflation chamber. A piston (25) is slidably mounted in the body to define a watertight separation between a chamber (26) containing a given quantity of a reference gas and another chamber (27) into which the opening leads such that the piston is subjected to opposing pressures existing in each of the two chambers. A linear variable differential transformer (LVDT) type sensor (30) senses a position of the piston in the body. The inflation chamber is situated between a rim and a tire of a wheel and containing inflation gas.