Gas Sensor Reference-Gas Pumping for Moisture-Stable Detection
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Solution Overview
Problem
The adsorption of external water in the reference-gas introduction section of a gas sensor leads to a decrease in oxygen concentration around the reference electrode, affecting the detection accuracy of specific gas concentrations.
Innovation Solution
A gas sensor with a reference-gas adjustment pump cell that pumps out oxygen from the periphery of the reference electrode to the measurement-object-gas side electrode, and optionally pumps oxygen back in to compensate for oxygen loss, thereby reducing moisture concentration around the reference electrode.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the reference-gas introduction section is left idle during non-driving periods, then the sensor structure remains simple, but external water is adsorbed causing decreased detection accuracy
Solution Approach 1:
The patent applies preliminary action by performing a moisture-concentration decrease process before actual gas detection begins. The controller activates the reference-gas adjustment pump cell to pump out oxygen and decompose adsorbed water during non-driving periods, preparing the reference electrode environment in advance. This preliminary moisture removal ensures detection accuracy is maintained when the sensor starts operating, resolving the contradiction between simple structure and reliable performance.
2Object-affected harmful factors
If the sensor is heated to release adsorbed water, then moisture is removed from the reference-gas introduction section, but oxygen concentration around the reference electrode decreases affecting detection accuracy
Solution Approach 1:
The patent implements continuity of useful action by continuously operating the reference-gas adjustment pump cell to maintain oxygen concentration around the reference electrode. While moisture is being removed through heating and water decomposition, the pump cell continuously supplies oxygen to the reference electrode side, ensuring that oxygen concentration remains sufficient for accurate detection throughout the moisture removal process and subsequent operation.
Solution Approach 2:
The reference-gas adjustment pump cell acts as an intermediary mechanism that mediates between moisture removal and oxygen concentration maintenance. It pumps out oxygen during moisture decomposition but can also supply oxygen when needed, serving as a buffer that decouples the harmful effect of oxygen loss from the beneficial effect of moisture removal, thereby maintaining detection precision.
3Productivity
If oxygen is pumped out to decompose moisture quickly, then moisture concentration decreases rapidly improving detection reliability, but oxygen concentration around the reference electrode drops affecting measurement precision
Solution Approach 1:
The patent applies periodic action by alternately performing oxygen pumping out and pumping in operations of the reference-gas adjustment pump cell. During periods when moisture needs rapid removal, oxygen is pumped out to accelerate water decomposition. When oxygen concentration around the reference electrode drops, the pump cell switches to pumping oxygen in to restore it. This periodic switching enables rapid moisture removal while maintaining adequate oxygen concentration for detection precision.
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 approach quickly decreases moisture concentration around the reference electrode, preventing a decrease in detection accuracy caused by moisture and maintaining precise gas concentration measurements.
Implementation Method 1
controlling the reference-gas adjustment pump cell so that oxygen is pumped out from a periphery of the reference electrode to a periphery of the measurement-object-gas side electrode
Implementation Method 2
an element body including an oxygen-ion-conductive solid electrolyte layer
Implementation Method 3
the sensor element is heated when the driving is started, the water in the reference-gas introduction section becomes a gas and is released outward
Data Source
AI summary
A gas sensor that detects a specific gas concentration in a measurement-object gas, the gas sensor includes: a sensor element having an element body provided with a measurement-object gas flow section therein, the measurement-object gas flow section introducing the measurement-object gas, a measurement electrode disposed in the measurement-object gas flow section, a measurement-object-gas side electrode provided on the element body, a reference electrode, a reference-gas introduction section that causes a reference gas to flow to the reference electrode, and a reference-gas adjustment pump cell constituted by including the measurement-object-gas side electrode and the reference electrode; and a controller that performs a moisture-concentration decrease process of controlling the reference-gas adjustment pump cell so that oxygen is pumped out from a periphery of the reference electrode to a periphery of the measurement-object-gas side electrode to decrease a moisture concentration around the reference electrode.