Gas Sensor Pump-Cell Control for Dual Gas and Water Detection
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Solution Overview
Problem
Existing gas sensors are unable to simultaneously detect the concentration of specific gases and water concentration in measurement-object gases, as their structures and detection methods differ, leading to a lack of a unified method for both types of measurements.
Innovation Solution
A gas sensor with an oxygen-ion-conductive solid electrolyte layer and internal gas flow portion, equipped with measurement and adjustment pump cells, uses control apparatuses to adjust oxygen concentration and detect specific gas and water concentrations based on changes in pump current when target voltage values are altered.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a gas sensor uses an oxygen concentration adjustment chamber and measurement chamber structure to detect specific gas concentration, then specific gas detection capability is improved, but water concentration detection capability is lost
Solution Approach 1:
The patent applies multi-functionality by enabling the measurement pump cell to perform both specific gas concentration detection and water concentration detection. The control apparatus achieves this by switching between different voltage target values: using a first voltage target value for specific gas detection and a second voltage target value for water concentration detection, thus making a single sensor structure capable of multiple detection functions.
2Adaptability or versatility
If the sensor structure follows PTL 2 design without oxygen concentration adjustment chamber, then water detection is enabled, but specific gas concentration detection capability is lost
Solution Approach 1:
The patent integrates both detection capabilities into a single sensor by maintaining the oxygen concentration adjustment chamber and measurement chamber structure while enabling water concentration detection through voltage target value switching. This allows the sensor to function as both a specific gas detector and a water concentration detector without requiring separate sensor structures.
3Ease of operation
If water concentration is not corrected in the measurement pump current, then detection simplicity is maintained, but measurement accuracy deteriorates due to water interference
Solution Approach 1:
The patent applies feedback correction by measuring water concentration through pump current changes at a second voltage target value, then using this water concentration information to correct the pump current measurements taken at the first voltage target value. This feedback mechanism compensates for water interference, improving measurement accuracy while maintaining operational simplicity through automated correction.
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
Enables simultaneous detection of specific gas and water concentrations in measurement-object gases, improving accuracy by correcting for water concentration and temperature effects on measurement pump current.
Implementation Method 1
an element body including an oxygen-ion-conductive solid electrolyte layer
Implementation Method 2
a measurement pump cell constituted by including an inner measurement electrode disposed in a measurement chamber, the measurement pump cell being configured to pump out oxygen in the measurement chamber
Implementation Method 3
an adjustment pump cell constituted by including an inner adjustment electrode disposed in an oxygen concentration adjustment chamber, the adjustment pump cell being configured to adjust an oxygen concentration in the oxygen concentration adjustment chamber
Implementation Method 4
detects the specific gas concentration and a water concentration in the measurement-object gas based on a change in a measurement pump current which flows during execution of the adjustment pump control process and the measurement pump control process when at least one of the adjustment voltage target value or the measurement voltage target value is changed
Data Source
AI summary
A gas sensor includes a sensor element including an element body, a measurement pump cell including an inner measurement electrode, an adjustment pump cell including an inner adjustment electrode and a reference electrode, a control apparatus that performs an adjustment pump control process of adjusting the oxygen concentration in the oxygen concentration adjustment chamber so that an adjustment voltage reaches an adjustment voltage target value, and a measurement pump control process of pumping out oxygen in the measurement chamber so that a measurement voltage reaches a measurement voltage target value. The control apparatus detects the specific gas concentration in the measurement-object gas based on a measurement pump current, and the control apparatus detects a water concentration in the measurement-object gas based on a change in the measurement pump current when at least one of the adjustment voltage target value or the measurement voltage target value is changed.