Spiral Capillary Gas Sensor for Exhaust Tracts
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Solution Overview
Problem
Existing gas sensors for detecting multiple components in exhaust gases are costly, temperature-sensitive, and limited in their ability to operate in aggressive environments, with a lack of sensitivity to various gas components.
Innovation Solution
A sensor featuring a spiral capillary with a reflective surface that absorbs electromagnetic radiation, allowing for qualitative and quantitative detection of gas components through absorption spectroscopy, with a gas conditioning unit for pre-cleaning and a compact design suitable for aggressive environments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If solid electrolyte sensors are used for gas detection, then they can detect certain gas components (NO, NH3, O2), but they require precious metals, high operating temperatures, and are susceptible to thermal shocks and water droplets
Solution Approach 1:
The patent replaces solid electrolyte sensors with optical sensors that use light transmission through a waveguide to detect gas components. This substitution eliminates the need for high-temperature operation and precious metals, while avoiding susceptibility to thermal shocks and water droplets. The optical detection method uses absorption spectroscopy where gas molecules absorb specific wavelengths of light, enabling detection without thermal or electrochemical processes.
2Measurement precision
If solid electrolyte sensors are used, then electrochemical reactions can occur at electrodes, but the sensors are expensive to manufacture and require precious metals such as platinum or rhodium
Solution Approach 1:
The patent employs optical components and waveguides that eliminate the need for expensive precious metals like platinum or rhodium. The optical sensor system uses standard optical materials and light sources that are significantly cheaper than the precious metal electrodes required by solid electrolyte sensors, while maintaining the capability to detect gas concentrations through optical absorption methods.
3Adaptability or versatility
If radiation absorption spectroscopy is used with a waveguide, then multiple gas components can be detected, but the device complexity increases with gas supply and discharge devices
Solution Approach 1:
The patent integrates the gas detection function directly into the waveguide structure itself, eliminating the need for separate gas supply and discharge devices. The waveguide serves as both the optical transmission medium and the measurement cell where gas molecules interact with the light. This merging of functions reduces device complexity while maintaining the ability to detect multiple gas components through their characteristic absorption spectra.
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 sensor provides high accuracy and reliability in detecting multiple gas components, even in low concentrations, with enhanced sensitivity and durability, enabling effective use in combustion engine exhaust systems and other challenging environments.
Implementation Method 1
The capillary, in particular its capillary wall, is designed to suppress, i.e., at least counteract or completely prevent, the escape of electromagnetic radiation flowing inside the capillary
Implementation Method 2
A sensor featuring a spiral capillary with a reflective surface that absorbs electromagnetic radiation
Implementation Method 3
allowing for qualitative and quantitative detection of gas components through absorption spectroscopy
Data Source
Figure 1
Figure 2a~2c
Figure 3
AI summary
The invention relates to a sensor (10) for detecting a gas. The sensor (20) has a spiral-shaped capillary (21) as the measuring cell (20), said capillary comprising a cavity (21.2) into which both the measured gas as well as electromagnetic radiation are coupled. A gas component is detected by detecting the absorption. The sensor (10) is suitable in particular for use in the exhaust tracts of internal combustion engines of vehicles.