Gas Sensor Diffusion Control for Stable NOx Detection
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Solution Overview
Problem
The dynamic pressure of the measurement-object gas affects the accuracy of gas concentration detection in existing gas sensors, particularly in NOx detection, due to variations in pump cell operation.
Innovation Solution
A sensor element with a diffusion control section that includes a porous body and space portions, providing diffusion resistance and causing turbulence in the measurement-object gas flow, thereby reducing the effect of dynamic pressure on the pump cell.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a conventional gas sensor structure is used, then the sensor can detect gas concentration, but the dynamic pressure of measurement-object gas affects the accuracy of detection
Solution Approach 1:
The patent introduces a porous body in the diffusion control section that provides diffusion resistance to the measurement-object gas. The porous structure allows gas molecules to pass through while creating a controlled diffusion path that stabilizes the gas flow characteristics, reducing the impact of dynamic pressure variations on pump cell operation and improving detection accuracy
Solution Approach 2:
The patent modifies the physical parameters of the diffusion control section by incorporating both a porous body and space portions, changing the flow regime from direct flow to diffusion-controlled flow. This parameter change in the transport mechanism stabilizes the gas flow and reduces sensitivity to dynamic pressure changes
2Adaptability or versatility
If the pump cell operates in varying dynamic pressure conditions, then the sensor can function, but the pump cell operation varies affecting measurement accuracy
Solution Approach 1:
The porous body creates a diffusion-controlled environment that decouples the pump cell operation from external dynamic pressure variations. Gas molecules must diffuse through the porous structure to reach the pump cell, creating a stable mass transport condition that maintains consistent pump cell operation across varying pressure conditions
Solution Approach 2:
The diffusion control section with porous body and space portions acts as an intermediary between the measurement-object gas inlet and the pump cell. This intermediary structure stabilizes the gas flow characteristics before the gas reaches the pump cell, isolating the pump cell from dynamic pressure fluctuations
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 diffusion control section enhances the accuracy of NOx concentration detection by stabilizing the gas flow, allowing for precise measurement despite variations in dynamic pressure.
Implementation Method 1
a diffusion control section that is located upstream of the internal cavity in the measurement-object gas flow section and that provides the measurement-object gas introduced from the gas inlet with diffusion resistance
Implementation Method 2
causing turbulence in the measurement-object gas flow, thereby reducing the effect of dynamic pressure on the pump cell
Data Source
AI summary
A sensor element for detecting a concentration of a specific gas in a measurement-object gas, the sensor element includes: the element body having a measurement-object gas flow section inside that introduces the measurement-object gas and causes the measurement-object gas to flow in a first direction; a diffusion control section that is located in the measurement-object gas flow section, wherein the diffusion control section includes a porous body and a space portion that are provided in at least part of the diffusion control section in the first direction, the porous body is provided so as to occupy a part of a cross-section of the diffusion control section perpendicular to the first direction and allows the measurement-object gas to pass therethrough, and the space portion includes a part of the cross-section not occupied by the porous body and allows the measurement-object gas to pass therethrough.