Ozone Sensor Optical Path Segmentation for Aircraft Cabin Air

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Solution Overview

Problem

Current ozone detection systems in aircraft cabins are not ruggedized to handle vibration, temperature changes, pressure variations, and humidity, leading to inaccurate measurements of ozone concentrations near regulatory limits.

Innovation Solution

A gas-concentration system using a temperature-controlled UV light source and detector, combined with a pressure sensor and ozone-inert housing, to reduce signal drift and noise, and withstand aerospace conditions, including high g-forces.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If a single optical pathway is used for ozone detection, then the device complexity is reduced, but measurement precision deteriorates due to detector drift and environmental noise

Engineering Contradiction:
Improveoptical pathway configurationVSAvoidozone concentration measurement
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The optical pathway is segmented into multiple independent channels (first optical pathway and second optical pathway), each with its own detector. This segmentation allows independent measurement and comparison of light absorption at different wavelengths, enabling differentiation between ozone absorption and environmental interference, thereby improving measurement precision without excessive complexity

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

A reference optical pathway is introduced as an intermediary element that measures environmental noise and interference separately. The reference pathway's measurements serve as a mediator to compensate for detector drift and environmental noise in the primary measurement pathway, improving accuracy while maintaining manageable system complexity

Inventive Principle:
Principle #24Intermediary (Mediator)

2Measurement precision

If the detector is made sensitive to detect low ozone concentrations near regulatory limits, then measurement precision is improved, but reliability deteriorates due to increased susceptibility to detector drift and environmental noise

Engineering Contradiction:
Improvelow concentration detection capabilityVSAvoidmeasurement stability under environmental conditions
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The system implements feedback by continuously monitoring environmental noise through the reference optical pathway and using this information to compensate for drift in the primary measurement pathway. The dual-pathway design provides real-time feedback on detector performance and environmental conditions, allowing the system to maintain reliability while detecting low ozone concentrations

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The system changes the wavelength parameter by using multiple optical pathways with different wavelengths - one optimized for ozone detection and another for reference measurements. This parameter differentiation allows the system to maintain high sensitivity for low concentration detection while using the reference wavelength to track and compensate for drift, thereby maintaining reliability

Inventive Principle:
Principle #35Parameter changes

3Reliability

If the sensor is ruggedized to withstand vibration, temperature changes, pressure variations and humidity, then reliability is improved, but device complexity increases

Engineering Contradiction:
Improveperformance under aerospace environmental conditionsVSAvoidenvironmental protection mechanisms
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The optical pathways and detectors are enclosed in an ozone-inert housing that creates a protected internal environment. This inert enclosure shields the sensitive optical components from external environmental factors including vibration, temperature changes, pressure variations, and humidity, improving reliability without requiring complex active compensation mechanisms for each environmental parameter

Inventive Principle:
Principle #39Inert atmosphere (Inert environment)

Solution Approach 2:

Multiple environmental protection functions are merged into a single integrated housing structure that provides mechanical protection, thermal isolation, pressure containment, and chemical inertness simultaneously. This consolidation of protection mechanisms into one unified structure achieves ruggedization while minimizing the increase in device complexity compared to separate protection systems for each environmental factor

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

The system provides accurate ozone concentration measurements near regulatory limits, ensuring safe cabin air quality by reducing detector drift and noise from environmental factors.

Implementation Method 1

a gas-concentration system may include a source of sample gas containing a concentration of ozone and a single optical pathway

Methodology Applied
Scientific EffectAbsorption Spectroscopy: Absorption Spectroscopy

Implementation Method 2

Gas-concentration systems and detection techniques described herein may reliably measure a concentration of a gas contaminants by reducing detector drift, thermally induced noise

Methodology Applied
Scientific EffectThermal noise reduction:

Data Source

PatentEP3936862B1Cabin air sensor for ozone detection
Publication Date: 2023.09.20 HONEYWELL INTERNATIONAL INC
  • EP3936862B1 patent drawingFigure 1
  • EP3936862B1 patent drawingFigure 2
  • EP3936862B1 patent drawingFigure 3

AI summary

A method of measuring a gas concentration is described. The method comprises illuminating, with a light source, a volume of space that includes a gas and measuring, with a detector, a first illumination level of the volume of space. The method further comprises determining, via a processor, a gas concentration in the volume of space based on the measured first illumination level, where the volume of space is configured to be in fluid communication with a gas recirculation flow path including a catalyst, the catalyst configured to substantially remove the gas from the volume of space.