Multi-Sensor Optical Device for Exhaust Gas Detection

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Solution Overview

Problem

Existing burnt-gas sensors in the motor-industry sector face challenges with low sensitivity and selectivity, as well as instability in extreme environmental conditions and the presence of corrosive chemical agents, limiting their effectiveness in accurately detecting and measuring nitrogen oxides and other pollutants.

Innovation Solution

A multi-sensor optical device comprising a first and second optoelectronic sensor, both sensitive to specific wavelength ranges, which utilize UV radiation to detect nitrogen monoxide and nitrogen dioxide concentrations through absorption cross-section analysis, allowing for simultaneous detection and precise concentration determination.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If burnt-gas sensors based on electrical characteristic variation are used, then low cost and simplicity of construction are achieved, but sensitivity and selectivity are not particularly high

Engineering Contradiction:

Improvesimplicity of constructionVSAvoidsensitivity

Core Design Contradiction:

Ease of manufactureVSMeasurement precision

Solution Approach 1:

The patent replaces electrical characteristic-based detection with optical detection methods. Instead of measuring electrical properties that vary with chemical absorption, the invention uses optical sensors to detect changes in optical properties (absorption, reflection, fluorescence) when chemical species interact with the sensing material, thereby achieving higher sensitivity while maintaining construction simplicity

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the detection parameter from electrical characteristics to optical characteristics. By measuring optical properties such as light absorption, reflection, or fluorescence intensity instead of electrical conductivity or resistance, the system achieves enhanced sensitivity and selectivity for detecting chemical species in exhaust gases

Inventive Principle:

Principle #35Parameter changes

2Ease of manufacture

If burnt-gas sensors based on electrical characteristic variation are used, then low cost and simplicity of construction are achieved, but selectivity is not particularly high

Engineering Contradiction:

Improvesimplicity of constructionVSAvoidselectivity

Core Design Contradiction:

Ease of manufactureVSMeasurement precision

Solution Approach 1:

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

Inventive Principle:

Principle #35Parameter changes

3Reliability

If conventional sensors are used in extreme environmental conditions, then high temperature resistance is achieved, but sensitivity and response speed are compromised

Engineering Contradiction:

Improveresistance to high temperaturesVSAvoidsensitivity

Core Design Contradiction:

ReliabilityVSMeasurement precision

Solution Approach 1:

The patent employs composite sensing structures that combine materials with high temperature resistance (such as ceramic substrates or heat-resistant coatings) with sensing materials that maintain their optical properties at elevated temperatures. This composite approach allows the sensor to withstand extreme environmental conditions while preserving high sensitivity and fast response characteristics

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

4Reliability

If conventional sensors are used in extreme environmental conditions, then high temperature resistance is achieved, but response speed is compromised

Engineering Contradiction:

Improveresistance to high temperaturesVSAvoidresponse speed

Core Design Contradiction:

ReliabilityVSSpeed

Solution Approach 1:

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

5Measurement precision

If optical filter is coupled to optical detector in a controlled way, then high accuracy detection of multiple chemical species is achieved, but device complexity and overall dimensions increase

Engineering Contradiction:

ImproveaccuracyVSAvoidcomplexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent divides the detection system into multiple optical channels, each with its own optical filter and detector combination. This segmentation allows simultaneous detection of multiple chemical species at different wavelengths, achieving high accuracy while maintaining a relatively simple modular structure that can be integrated into compact form factors

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent employs a multi-functional optical detection system where a single device can detect multiple chemical species (such as CO, CO2, NOx, HC) by utilizing multiple optical sensors with different spectral sensitivities. This universal approach eliminates the need for separate dedicated sensors for each chemical species, thereby reducing overall device complexity

Inventive Principle:

Principle #6Universality (Multi-functionality)

6Measurement precision

If optical filter is coupled to optical detector in a controlled way, then high accuracy detection of multiple chemical species is achieved, but overall dimensions increase

Engineering Contradiction:

ImproveaccuracyVSAvoidoverall dimensions

Core Design Contradiction:

Measurement precisionVSVolume of moving object

Solution Approach 1:

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Inventive Principle:

Principle #6Universality (Multi-functionality)

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 device achieves high sensitivity and stability in detecting nitrogen oxides, maintaining performance at high temperatures and in corrosive environments, with compact dimensions and adaptability for various chemical species, enabling accurate concentration measurement.

Implementation Method 1

a first optical sensor configured to be optically coupled to the optical source through a specimen, the specimen having a first chemical species and a second chemical species, the first optical sensor being sensitive to radiation having a wavelength in a first range of wavelengths, and a second optical sensor configured to be optically coupled to the optical source through the specimen, the second optical sensor being sensitive to radiation having a wavelength in a second range of wavelengths

Methodology Applied

Scientific EffectAbsorption spectroscopy: Absorption Spectroscopy

Data Source

PatentUS11037965B2Multi-sensor optical device for detecting chemical species and manufacturing method thereof

Publication Date: 2021.06.15 STMICROELECTRONICS INT NV

AI summary

An optical device for detecting a first chemical species and a second chemical species contained in a specimen, which includes: a first optical sensor, which may be optically coupled to an optical source through the specimen and is sensitive to radiation having a wavelength comprised in a first range of wavelengths; and a second optical sensor, which may be optically coupled to the optical source through the specimen and is sensitive to radiation having a wavelength comprised in a second range of wavelengths, different from the first range of wavelengths.