Aircraft Air Conditioning Noise Testing for Fault Detection

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Solution Overview

Problem

The onboard air conditioning system in aircraft is challenging to test accurately due to the complex arrangement of tubes, making temperature measurement inaccessible and unreliable, which hinders effective maintenance and fault detection.

Innovation Solution

A sound-based testing equipment comprising a sound receiver and processor that analyzes the running noise of the air conditioning system to assess its operative condition, determine failure sources, and predict deterioration by comparing noise waveforms and frequency spectrums with standard or historical data.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If temperature sensors and electric power circuits are mounted at key positions to measure temperature, then measurement precision is improved, but device complexity and ease of operation deteriorate due to complex tube arrangements making measurement points inaccessible

Engineering Contradiction:

Improvetemperature measurement accuracyVSAvoidcomplexity of temperature acquisition system

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent replaces the mechanical temperature measurement system (temperature sensors, electric power circuits, signal transmission lines) with an acoustic measurement system (microphone, sound processor). The sound processor analyzes running noise characteristics to assess operative conditions, determining failure sources and causes without physical contact with the complex tube arrangements.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent introduces sound noise as an intermediary parameter to indirectly assess the operative condition of the air conditioning system. Instead of directly measuring temperature at inaccessible points, the system uses acoustic signals that can be captured externally and processed to infer system health status.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Measurement precision

If temperature sensors are mounted at key positions to obtain accurate measurement results, then measurement precision is improved, but ease of operation deteriorates due to inaccessibility of measurement points

Engineering Contradiction:

Improvetemperature measurement accuracyVSAvoidconvenience of temperature measurement

Core Design Contradiction:

Measurement precisionVSEase of operation

Solution Approach 1:

The patent replaces the mechanical temperature measurement system requiring physical sensor installation with an acoustic measurement system using a microphone and sound processor. This substitution enables convenient, non-intrusive measurement by analyzing running noise characteristics without accessing inaccessible measurement points.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The air conditioning system's own operating noise serves as the measurement signal. The system's正常运行 noise contains information about its operative condition, eliminating the need for separate measurement instruments to be installed within the system.

Inventive Principle:

Principle #25Self-service

3Reliability

If temperature sensors are installed to enable continuous monitoring, then reliability is improved, but ease of repair deteriorates due to the complexity of the temperature acquisition system

Engineering Contradiction:

Improvecontinuous monitoring capabilityVSAvoidmaintenance complexity of temperature acquisition system

Core Design Contradiction:

ReliabilityVSEase of repair

Solution Approach 1:

The patent replaces the complex temperature acquisition system requiring continuous maintenance with a simple acoustic measurement system. The microphone and sound processor provide continuous monitoring through noise analysis without the maintenance burden of sensors, circuits, and transmission lines installed in difficult-to-reach locations.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent creates a virtual model of the system's operative condition by analyzing and processing acoustic signals. The sound processor generates assessments of failure sources and causes based on noise pattern recognition, providing reliable continuous monitoring through information copying rather than direct physical measurement.

Inventive Principle:

Principle #26Copying

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 method allows for convenient, accurate, and cost-effective testing of the air conditioning system without the need for temperature sensors, enabling timely maintenance and reducing the risk of system failure, thereby enhancing passenger comfort and operational efficiency.

Implementation Method 1

a sound receiver and a sound processor, wherein the sound processor processes the running noise of an onboard air conditioning system sampled by the sound receiver

Methodology Applied

Scientific EffectSound: Sound

Data Source

PatentUS10156494B2Testing equipment of onboard air conditioning system and a method of testing the same

Publication Date: 2018.12.18 AIR CHINA LTD

AI summary

A testing equipment of an airplane air conditioning system is disclosed. The test equipment includes a sound receiver and a sound processor. The sound processor processes running noise of airplane air conditioning system sampled by the sound receiver to assess the operative condition of the system. The sound receiver samples environmental noise when the airplane air conditioning system is not running, and the sound processor de-noises the running noise by using the environmental noise.