Gas Sensor Reference Potential Control for Oxygen Stability

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Solution Overview

Problem

Existing gas sensors face challenges in maintaining the oxygen concentration around the reference electrode constant, leading to fluctuations in electrical potential and reduced accuracy in specific gas concentration detection.

Innovation Solution

A gas sensor with a control device that measures voltage across the ground and reference electrode to identify deviations in reference potential, adjusting oxygen concentration using pump cells to maintain accuracy by controlling the reference-gas adjustment and measurement pump cells.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a reference gas adjustment device is used to pump oxygen into the periphery of the reference electrode, then oxygen concentration can be compensated when it temporarily reduces, but it is difficult to maintain the oxygen concentration at a constant value completely

Engineering Contradiction:

Improvedetection accuracyVSAvoidoxygen concentration stability

Core Design Contradiction:

ReliabilityVSStability of the object's composition

Solution Approach 1:

The patent implements a feedback control mechanism where the control device continuously measures the voltage across the ground and reference electrode to monitor reference potential deviations. Based on the measured voltage, the control device adjusts the reference gas adjustment device to pump oxygen in or out, creating a closed-loop feedback system that maintains oxygen concentration stability and resolves the contradiction between compensation capability and constant maintenance difficulty

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The system enables self-regulation by using the measured voltage information to automatically control the reference gas adjustment device without external intervention. The control device autonomously identifies reference potential deviations and adjusts oxygen concentration accordingly, allowing the system to self-correct and maintain stable operation

Inventive Principle:

Principle #25Self-service

2Measurement precision

If the oxygen concentration in the periphery of the reference electrode changes, then the electrical potential of the reference electrode changes, but this leads to decreased accuracy of detection of the specific gas concentration

Engineering Contradiction:

Improvespecific gas concentration detection accuracyVSAvoidreference potential stability

Core Design Contradiction:

Measurement precisionVSReliability

Solution Approach 1:

The control device uses feedback control by continuously measuring the voltage across the ground and reference electrode to monitor reference potential stability. When deviations are detected, the system automatically adjusts the reference gas adjustment device to restore oxygen concentration, thereby maintaining reference potential stability and ensuring accurate specific gas concentration detection

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The patent replaces direct mechanical monitoring of oxygen concentration with an electrical measurement approach. By measuring the voltage across the ground and reference electrode, the system indirectly monitors reference potential deviations caused by oxygen concentration changes, substituting direct chemical measurement with electrical detection for more precise and reliable control

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

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 solution effectively identifies and corrects deviations in reference potential, ensuring accurate detection of specific gas concentrations by stabilizing oxygen concentration, thereby enhancing the sensor's precision.

Implementation Method 1

an element body including an oxygen-ion-conductive solid electrolyte layer

Methodology Applied

Scientific EffectOxygen ion conduction: Conduction (electrical)

Implementation Method 2

a reference-gas adjustment pump cell constituted by including a measurement-object-gas side electrode and the reference electrode... oxygen is pumped into the periphery of the reference electrode

Methodology Applied

Scientific EffectOxygen pumping: Pump

Implementation Method 3

the control device measures a voltage across a ground and the reference electrode, and identifies a deviation of a reference potential that is an electrical potential of the reference electrode based on the measured voltage

Methodology Applied

Scientific EffectVoltage measurement: Electrical Resistance

Data Source

PatentUS12618799B2Gas sensor and method of identifying deviation of reference potential of the same

Publication Date: 2026.05.05 NGK INSULATORS LTD

AI summary

A gas sensor includes a sensor element and a control device, and detects a specific gas concentration that is a concentration of a specific gas in a measurement-object gas. The sensor element includes an element body including an oxygen-ion-conductive solid electrolyte layer and provided with a measurement-object gas flow portion therein, the measurement-object gas flow portion introducing the measurement-object gas and causing the measurement-object gas to flow therethrough; a measurement electrode disposed in a measurement chamber of the measurement-object gas flow portion; and a reference electrode disposed inside the element body to come into contact with a reference gas that serves as a reference for detection of the specific gas concentration. The control device measures a voltage across the ground and the reference electrode, and identifies a deviation of the reference potential that is the electrical potential of the reference electrode based on the measured voltage.