Particulate Sensor Insulating Spacer Heater

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Solution Overview

Problem

The insulating spacer in particulate sensors attached to metal gas flow pipes experiences deterioration in insulation due to foreign substances like soot and water droplets adhering to the gas contact portion, leading to improper detection of particulates in exhaust gas.

Innovation Solution

Incorporating a heater with a heat generation resistor embedded in the insulating spacer that heats the gas contact portion, effectively removing foreign substances by evaporation or burning, thereby maintaining insulation and ensuring accurate particulate detection.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If the insulating spacer is exposed to exhaust gas for particulate detection, then detection capability is improved, but insulation deteriorates due to foreign substance adhesion

Engineering Contradiction:

Improveparticulate detection capabilityVSAvoidinsulation performance

Core Design Contradiction:

Measurement precisionVSReliability

Solution Approach 1:

The heater embedded in the insulating spacer performs preliminary heating action to prevent foreign substances from adhering to the gas contact portion. By maintaining the surface temperature above the dew point and combustion temperature, the heater proactively eliminates the condition that would lead to insulation deterioration, thus preserving both detection capability and insulation performance over extended periods

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The heater converts the harmful effect of foreign substance adhesion into a beneficial cleaning action. By heating the gas contact portion, the heater causes water droplets to evaporate and soot to combust, transforming the accumulation of harmful substances into a self-cleaning mechanism that maintains insulation performance while continuing to detect particulates

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

2Measurement precision

If the gas contact portion contacts exhaust gas continuously, then detection accuracy is maintained, but foreign substances accumulate and reduce insulation

Engineering Contradiction:

Improveparticulate detection accuracyVSAvoidinsulation durability

Core Design Contradiction:

Measurement precisionVSDuration of action of stationary object

Solution Approach 1:

The heater operates continuously or periodically to maintain the gas contact portion at a temperature that prevents foreign substance accumulation. This continuous heating action ensures that the insulating spacer maintains its insulation performance over extended periods while continuously contacting exhaust gas for accurate particulate detection

Inventive Principle:

Principle #20Continuity of useful action

Solution Approach 2:

The insulating spacer performs self-cleaning through the heater embedded within it. The heating element causes water droplets to evaporate and soot to combust automatically, eliminating the need for external maintenance or cleaning operations while preserving both detection accuracy and insulation durability

Inventive Principle:

Principle #25Self-service

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 maintains the insulation of the insulating spacer, allowing for reliable detection of particulates in the target gas over extended periods by preventing foreign substance adhesion and ensuring consistent heating performance.

Implementation Method 1

the heater includes a heat generation resistor embedded in the insulating spacer

Methodology Applied

Scientific EffectJoule heating: Joule Heating

Implementation Method 2

foreign substances (e.g., soot and water droplets) contained in exhaust gas may adhere to the gas contact portion... heating the gas contact portion, effectively removing foreign substances by evaporation or burning

Methodology Applied

Scientific EffectEvaporation: Evaporation

Implementation Method 3

heating the gas contact portion, effectively removing foreign substances by evaporation or burning

Methodology Applied

Scientific EffectCombustion: Combustion

Data Source

PatentUS10209173B2Particulate sensor

Publication Date: 2019.02.19 NITERRA CO LTD

AI summary

A particulate sensor includes: an inner metallic member which is maintained at a first potential and which has a gas introduction pipe into which a target gas is introduced; a tubular outer metallic member which surrounds the radially outer circumference of the inner metallic member and which is attached to a gas flow pipe to thereby be maintained at a ground potential; and an insulating spacer which is interposed between the inner metallic member and the outer metallic member so as to electrically insulate them from each other and which has a tubular gas contact portion which is exposed to the interior of the gas flow pipe and comes into contact with the gas under measurement. The insulating spacer has a heater for heating the gas contact portion. The heater includes a heat generation resistor embedded in the insulating spacer.