Gas Sensor Reference Potential Diagnosis for Stable Detection
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Solution Overview
Problem
The detection accuracy of gas sensors can be reduced when the oxygen concentration in the reference gas around the reference electrode changes, especially when it is not at a specific timing where the oxygen concentration in the measurement-object gas is known.
Innovation Solution
A gas sensor configuration with a sensor element and control unit that includes a reference gas chamber, intracavity and extracavity electrodes, and a control unit capable of diagnosing and correcting deviations in the reference potential of the reference electrode by comparing diagnostic and standard correspondence relationships of voltage and current.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the reference electrode is disposed in a reference gas chamber independently provided in the element body, then the reference electrode can be protected and the detection system can be simplified, but the oxygen concentration in the reference gas may change over time causing reduction in detection accuracy
Solution Approach 1:
The patent implements a feedback mechanism where the control unit continuously monitors the voltage between the intracavity electrode and reference electrode, compares it with stored standard values, and diagnoses deviations in reference potential. This feedback loop enables continuous correction of detection accuracy without requiring complex external reference gas supply systems.
Solution Approach 2:
The sensor performs self-diagnosis and self-correction by using its own electrodes and voltage measurements to detect reference potential deviations. The control unit stores standard correspondence relationships between voltage and current, and automatically diagnoses deviations without requiring external calibration equipment or complex reference gas management.
2Measurement precision
If the oxygen concentration in measurement-object gas is used to determine reference gas oxygen concentration, then the system can maintain detection accuracy at specific timings, but cannot detect changes in reference gas oxygen concentration during other times
Solution Approach 1:
The patent stores standard correspondence relationships between voltage and current at standard times when reference potential is known to be at predetermined values. This preliminary storage of reference data enables later comparison and diagnosis of deviations at any time during sensor operation, not just at specific calibration moments.
Solution Approach 2:
The control unit continuously compares real-time voltage measurements with stored standard values, providing continuous feedback on reference potential deviations. This enables detection and correction of reference gas oxygen concentration changes at any timing, not only when measurement-object gas oxygen concentration is known.
3Stability of the object's composition
If the reference gas chamber is sealed to separate reference gas from measurement-object gas, then the reference gas can be maintained independently, but changes in reference gas oxygen concentration cannot be detected or corrected
Solution Approach 1:
The patent implements a feedback mechanism where the control unit continuously monitors the voltage between the intracavity electrode and reference electrode, compares it with stored standard values, and diagnoses deviations in reference potential. This feedback loop enables continuous correction of detection accuracy without compromising the sealed reference gas chamber.
Solution Approach 2:
The patent uses the voltage signal between electrodes as an intermediary to indirectly monitor reference gas oxygen concentration changes. Instead of directly measuring reference gas composition, the system uses electrical potential differences as a mediator to detect and correct reference gas changes while maintaining chamber sealing.
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 allows for continuous detection accuracy by diagnosing and correcting deviations in the reference potential of the reference electrode, maintaining high detection accuracy of the target gas in the measurement-object gas.
Implementation Method 1
a base part in an elongated plate shape, including an oxygen-ion-conductive solid electrolyte layer
Implementation Method 2
a pump cell including: an intracavity electrode disposed in the measurement-object gas flow cavity; and an extracavity electrode disposed at a position different from the measurement-object gas flow cavity on the base part and corresponding to the intracavity electrode
Implementation Method 3
a reference electrode disposed in the reference gas chamber
Implementation Method 4
obtaining a diagnostic correspondence relationship of a voltage between the intracavity electrode and the reference electrode with a current flowing through the pump cell
Data Source
AI summary
A gas sensor includes a sensor element and a control unit thereof. The sensor element includes: a base part; a measurement-object gas flow cavity formed from one end part in a longitudinal direction of the base part; a pump cell including an intracavity electrode disposed in the measurement-object gas flow cavity; and a reference electrode disposed in a reference gas chamber formed inside the base part. The control unit includes: a driving control part; a storing part storing in advance, a standard correspondence relationship at a standard time at which a reference potential of the reference electrode is at a predetermined value; and a diagnosing part obtaining a diagnostic correspondence relationship, and comparing the obtained diagnostic correspondence relationship with the standard correspondence relationship to diagnose a deviation of a reference potential of the reference electrode at the diagnostic time from the predetermined value at the standard time.