Gas Sensor Element With Tip-Side Heating for Flat VI Curves

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Solution Overview

Problem

Existing gas sensor elements face challenges in maintaining good flatness when the gas to be measured is introduced from the tip side, leading to variations in concentration and measurement errors due to insufficient activation of the solid electrolyte member near the measurement electrode.

Innovation Solution

The gas sensor element is designed with a heater where the heating center is located further to the tip side than the electrode center of the measurement electrode, ensuring sufficient temperature increase and activation of the solid electrolyte member near the tip part of the measurement electrode.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If the gas inlet is located at the tip side of the chamber, then the gas can be introduced into the chamber from the tip side, but the solid electrolyte member near the tip part of the measurement electrode is insufficiently activated leading to variations in concentration and measurement errors

Engineering Contradiction:

Improvegas introduction configurationVSAvoidmeasurement accuracy

Core Design Contradiction:

Ease of operationVSMeasurement precision

Solution Approach 1:

The heater is designed with non-uniform heating characteristics, concentrating heat at the tip side to specifically activate the solid electrolyte member near the tip part of the measurement electrode. This local heating approach ensures that the region where gas first enters the chamber receives sufficient thermal activation, eliminating concentration variations and measurement errors without overheating other regions.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The solid electrolyte member is pre-heated to a predetermined temperature before gas measurement begins. This preliminary thermal activation ensures that the solid electrolyte is fully activated and ready for accurate measurement, preventing concentration variations that would occur if the electrolyte were not properly activated when gas introduction starts.

Inventive Principle:

Principle #10Preliminary action

2Temperature

If the heater heats the solid electrolyte member uniformly, then the solid electrolyte member can be activated, but the tip part near the measurement electrode remains insufficiently activated when gas is introduced from the tip side

Engineering Contradiction:

Improvesolid electrolyte member temperatureVSAvoidflatness of VI curve

Core Design Contradiction:

TemperatureVSMeasurement precision

Solution Approach 1:

The heater is designed with asymmetric heating characteristics, with the heating center positioned at the tip side of the solid electrolyte member. This asymmetric configuration creates a temperature gradient that concentrates heat where it is most needed - at the tip part near the measurement electrode - ensuring proper activation without requiring uniform heating across the entire electrolyte member.

Inventive Principle:

Principle #4Asymmetry

Solution Approach 2:

The heating system provides differentiated temperature distribution across the solid electrolyte member, with higher temperatures concentrated at the tip side where gas introduction occurs. This local quality approach ensures that the critical region for measurement accuracy receives sufficient thermal activation while other regions are heated to appropriate but lower temperatures.

Inventive Principle:

Principle #3Local quality

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 enhances the flatness of the VI curve, reducing measurement errors and improving the responsiveness of the gas sensor element, even when the gas is introduced from the tip side.

Implementation Method 1

the gas sensor element has a heater for heating the solid electrolyte member

Methodology Applied

Scientific EffectJoule heating: Joule Heating

Implementation Method 2

the part of the solid electrolyte member forming a sensor cell is heated to a certain temperature so as to activate it and allow conduction of oxygen ions

Methodology Applied

Scientific EffectIon conduction: Conduction (electrical)

Data Source

PatentUS12345675B2Gas sensor element

Publication Date: 2025.07.01 DENSO CORP

AI summary

A limiting current-type gas sensor element including a plurality of stacked ceramic layers and configured to output a limiting current value which depends on a concentration of a specific gas in a gas to be measured when a certain voltage is applied. The gas sensor element includes a solid electrolyte member having oxygen ion conductivity; a heater that heats the solid electrolyte member; a measurement electrode and a reference electrode provided on the solid electrolyte member; a chamber facing the measurement electrode and into which the gas to be measured is introduced; a gas inlet located to a tip side of the chamber in a longitudinal direction; and a diffusion resistance part provided in the gas inlet. A heating center of the heater is located further to the tip side than an electrode center of the measurement electrode is.