Gas Sensor Oxygen Correction for Nitrogen Oxide Accuracy
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Solution Overview
Problem
Existing gas sensors face accuracy issues in detecting nitrogen oxide concentrations due to sudden changes in oxygen concentration in the reference gas chamber, leading to errors in the detected values of nitrogen oxide concentrations.
Innovation Solution
A gas sensor configuration that includes a measurement chamber, a reference gas chamber, and multiple cells with electrodes, where currents are detected and calculated to correct for changes in oxygen concentration in the reference gas chamber, ensuring accurate detection of nitrogen oxide concentrations by accounting for oxygen concentration fluctuations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a reference gas chamber is used to provide stable reference conditions for gas detection, then measurement reliability should improve, but sudden changes in oxygen concentration in the reference chamber cause errors in nitrogen oxide concentration detection
Solution Approach 1:
The patent uses the first current from the pump cell as feedback to detect oxygen concentration changes in the reference gas chamber. When the first current changes, indicating oxygen concentration variation, the system automatically corrects the second current (nitrogen oxide measurement) by subtracting the influence of oxygen concentration changes. This feedback mechanism resolves the contradiction by enabling the reference chamber to maintain its stabilizing function while compensating for oxygen fluctuations that would otherwise cause measurement errors.
Solution Approach 2:
The patent monitors changes in oxygen concentration (a parameter) in the reference gas chamber by detecting changes in the first current. When oxygen concentration parameters change, the system adjusts the nitrogen oxide concentration calculation by correcting the second current based on the magnitude of oxygen concentration changes. This parameter-based correction resolves the contradiction between using the reference chamber for stability and avoiding oxygen concentration interference.
2Productivity
If oxygen is discharged from the measurement chamber into the atmosphere through the pump cell, then oxygen removal efficiency should improve, but oxygen may enter the reference gas chamber causing concentration changes
Solution Approach 1:
The patent implements a feedback mechanism where the first current (oxygen concentration indicator) is continuously monitored. When oxygen concentration in the reference chamber changes (indicating oxygen has entered from the measurement chamber), the system detects this through the pump cell's electrical response and automatically corrects the nitrogen oxide measurement. This feedback allows high oxygen removal efficiency while compensating for reference chamber composition changes.
Solution Approach 2:
The patent converts the harmful effect of oxygen entering the reference chamber into a useful signal. The change in first current caused by oxygen intrusion is not treated as a failure but as a detectable parameter that triggers automatic correction of the nitrogen oxide measurement. By utilizing the electrical response to oxygen concentration changes, the system transforms a potential error source into a correction opportunity, maintaining both high oxygen removal efficiency and measurement accuracy.
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 configuration reduces the influence of oxygen concentration changes on the detected nitrogen oxide concentrations, enabling more accurate detection and reducing errors in the measurement process.
Implementation Method 1
a first cell that includes a first electrode provided in the measurement chamber and a second electrode provided in the reference gas chamber
Implementation Method 2
a second cell that includes a third electrode provided in the measurement chamber and a fourth electrode provided in the reference gas chamber
Implementation Method 3
In the pump cell, a current flows which depend on a concentration of oxygen while oxygen in the exhaust gas introduced into the measurement chamber is discharged into the atmosphere
Data Source
AI summary
A gas sensor includes a measurement chamber, a reference gas chamber, a first cell that includes a first electrode in the measurement chamber and a second electrode in the reference gas chamber, and a second cell that includes a third electrode in the measurement chamber and a fourth electrode in the reference gas chamber. The gas sensor detects a first current that flows through the first cell, detects a second current that flows through the second cell, calculates a concentration of a specific gas component based on a detected value of the second current, determines whether a change has occurred in an oxygen concentration in the reference gas chamber based on a detected value of the first current, and corrects the detected value of the second current when the gas sensor determines that a change has occurred in the oxygen concentration in the reference gas chamber.