Sequential-Chamber Gas Sensor for Low-Complexity CO2 and H2O Measurement
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Solution Overview
Problem
Existing gas sensors for measuring carbon dioxide and water vapor require a complex structure with multiple electrodes, leading to high manufacturing costs and reliability issues.
Innovation Solution
A multi-gas sensor with a simplified structure using fewer electrodes, employing a sensor element with oxygen-ion conductive solid electrolyte and a controller to measure water vapor and carbon dioxide concentrations through sequential chambers and intermittent pump cell operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple electrodes containing precious metals are arranged at five locations to measure CO2 and H2O concentrations, then measurement accuracy is improved, but device complexity and manufacturing cost increase
Solution Approach 1:
The patent combines multiple measurement functions into a single electrode arrangement. The sensor element uses one or more electrodes that perform both CO2 and H2O concentration measurements, eliminating the need for separate electrodes at five different locations. This merging reduces device complexity while maintaining measurement accuracy through sophisticated control algorithms that process signals from the reduced electrode configuration.
Solution Approach 2:
The electrode in this invention serves multiple functions: it measures CO2 concentration, measures H2O concentration, and provides reference potential for both measurements. This multi-functional electrode design replaces the need for multiple specialized electrodes, simplifying the overall sensor structure while preserving the ability to accurately measure multiple gas components simultaneously.
2Reliability
If five electrodes containing precious metals are used for parallel measurement of CO2 and H2O, then measurement reliability is improved, but manufacturing cost increases
Solution Approach 1:
The patent merges the functionality of five precious metal electrodes into a reduced configuration of one or more electrodes. This consolidation maintains measurement reliability through the use of a single robust electrode design that can simultaneously handle multiple measurement tasks, while dramatically reducing the quantity of expensive precious metals required, thus lowering manufacturing cost.
Solution Approach 2:
The invention replaces expensive precious metal electrodes with a more cost-effective electrode configuration. By using fewer electrodes with reduced precious metal content or alternative materials, the sensor achieves comparable reliability at a lower manufacturing cost, making the sensor more economically viable for widespread deployment.
3Adaptability or versatility
If five electrodes are arranged for parallel gas component measurement, then measurement capability is improved, but structure simplification is hindered
Solution Approach 1:
The patent combines multiple gas measurement capabilities into a simplified sensor structure with fewer electrodes. The single or reduced number of electrodes are designed to detect both CO2 and H2O concentrations through their electrical responses, eliminating the need for a complex five-electrode arrangement while maintaining full multi-gas measurement capability.
Solution Approach 2:
The electrode design in this patent is universal, capable of detecting multiple gas components (CO2 and H2O) simultaneously. This multi-functional electrode replaces multiple specialized electrodes, simplifying the sensor structure while preserving the ability to measure various gas components with high adaptability and versatility.
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 achieves accurate concentration measurement of multiple gas components with a simpler structure and reduced electrode count, lowering manufacturing costs while maintaining reliability.
Implementation Method 1
a sensor element including a structure formed of an oxygen-ion conductive solid electrolyte
Implementation Method 2
the first pump cell pumps out oxygen from the first chamber so that substantially all of water vapor and carbon dioxide contained in the measurement gas introduced through the gas inlet into the first chamber are decomposed
Implementation Method 3
the second pump cell pumps in oxygen to the second chamber to selectively oxidize, in the second chamber, hydrogen contained in the measurement gas, which has been generated by decomposition of water vapor
Implementation Method 4
the third pump cell pumps in oxygen to the third chamber to oxidize, in the third chamber, carbon monoxide contained in the measurement gas, which has been generated by decomposition of carbon dioxide
Implementation Method 5
a water vapor concentration identification element identifying a concentration of water vapor contained in the measurement gas based on a magnitude of a current flowing between the second inner electrode and the reference pump electrode
Implementation Method 6
a carbon dioxide concentration identification element identifying a concentration of carbon dioxide contained in the measurement gas based on a magnitude of a current flowing between the third inner electrode and the reference pump electrode
Data Source
AI summary
A sensor element includes first to third chambers communicating sequentially from a gas inlet, voltages are intermittently applied across inner electrodes facing the respective chambers and a reference pump electrode to perform pumping of oxygen between a measurement gas and the reference pump electrode being in contact with a reference gas, thereby to reduce H2O and CO2 in the measurement gas into H2 and CO in the first chamber, to oxidize H2 into H2O in the second chamber, to oxidize CO into CO2 in the third chamber, and to identify a concentration of H2O and a concentration of CO2 based on a pumping-in current at the time when electromotive force between an inner electrode and the reference pump electrode during non-application of a voltage is maintained at a target value.