Gas Sensor Control Apparatus for Solid Electrolyte Crack Detection

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Solution Overview

Problem

Existing gas sensors with solid electrolyte layers face challenges in detecting crack abnormalities, which lead to output errors, as current methods cannot accurately identify such issues, potentially resulting in erroneous corrections and reduced sensor accuracy.

Innovation Solution

A gas sensor control apparatus that applies a predetermined voltage or electric current between electrodes to determine crack abnormalities in the solid electrolyte layer by analyzing differences in oxygen supply quantity and electromotive force, allowing for proper identification and correction of sensor output.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If atmospheric air correction process is performed to correct gain error, then sensor output accuracy is improved for diffusion layer abnormalities, but crack abnormality of solid electrolyte layer cannot be identified leading to erroneous corrections

Engineering Contradiction:

Improvesensor output accuracyVSAvoidabnormality identification accuracy

Core Design Contradiction:

Measurement precisionVSReliability

Solution Approach 1:

The abnormality determination is segmented into two distinct processes: atmospheric air correction for gain error and crack abnormality determination. By separating these functions, the system can identify specific abnormality types (diffusion layer vs. solid electrolyte layer) and apply appropriate corrections, preventing erroneous corrections while maintaining sensor output accuracy.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

A predetermined voltage or electric current is applied as an intermediary test stimulus between the first and second electrodes to detect crack abnormalities. This intermediary action enables differentiation between normal operation and crack conditions by measuring oxygen supply quantity and electromotive force, allowing accurate abnormality identification before correction.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Productivity

If gain correction is performed without identifying crack abnormality, then sensor output is corrected for diffusion layer issues, but erroneous correction occurs on cracked sensors reducing accuracy

Engineering Contradiction:

Improvecorrection process efficiencyVSAvoidsensor output accuracy

Core Design Contradiction:

ProductivityVSMeasurement precision

Solution Approach 1:

Crack abnormality determination is performed as a preliminary action before gain correction. By first applying a predetermined voltage or current and measuring oxygen supply quantity and electromotive force, the system identifies crack abnormalities in advance, preventing erroneous corrections and ensuring sensor output accuracy is maintained.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The system uses feedback from the crack abnormality determination process to control whether gain correction should be applied. By measuring oxygen supply quantity and electromotive force during the preliminary test, the system receives feedback about the sensor's actual condition and adjusts the correction process accordingly, avoiding erroneous corrections on cracked sensors.

Inventive Principle:

Principle #23Feedback

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 enables accurate determination of crack abnormalities in the solid electrolyte layer, preventing erroneous corrections and improving sensor accuracy by utilizing the differences in oxygen supply and electromotive force between normal and cracked states.

Implementation Method 1

a sensor element having a solid electrolyte layer, a first electrode arranged on one side of the solid electrolyte layer so as to be exposed to the exhaust gas of an internal combustion engine, and a second electrode arranged on the other side of the solid electrolyte layer so as to face an atmospheric air chamber

Methodology Applied

Scientific EffectOxygen ion conduction through solid electrolyte: Conduction (electrical)

Implementation Method 2

an oxygen supply means for supplying oxygen to the first electrode side from the second electrode side via the solid electrolyte layer by applying a predetermined voltage or a predetermined electric current between the first and second electrodes

Methodology Applied

Scientific EffectElectrochemical oxygen pumping: Electrochemiluminescence

Data Source

PatentUS10082482B2Gas sensor control apparatus

Publication Date: 2018.09.25 DENSO CORP

AI summary

A sensor element of an A/F sensor AS has a solid electrolyte layer, a first electrode arranged on one side of the solid electrolyte layer so as to be exposed to the exhaust gas of an internal combustion engine, and a second electrode arranged on the other side of the solid electrolyte layer so as to face an atmospheric air chamber. The sensor element generates a sensor output according to the oxygen concentration in the exhaust gas. A microcomputer supplies oxygen to the first electrode side from the second electrode side via the solid electrolyte layer by applying a predetermined voltage between the pair of electrodes of the sensor element. Moreover, the microcomputer determines a crack abnormality of the solid electrolyte layer based on electric current between the pair of electrodes which is generated with start of the oxygen supply.