Exhaust Gas Processing Device Insulating Layer Design

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Solution Overview

Problem

Conventional exhaust gas processing devices with honeycomb structures face issues of electrical short-circuiting and inadequate heating due to moisture absorption by inorganic mat members, leading to current leakage and insufficient heating, especially under high humidity conditions.

Innovation Solution

The exhaust gas processing device incorporates a double pipe structure with insulating layers of varying thicknesses between the honeycomb structure and metallic members, preventing electrical short-circuits and maintaining sufficient insulation even when the inorganic mat members absorb moisture, ensuring effective resistance heating.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If inorganic mat members are used for insulation between metallic members, then insulation is provided, but moisture absorption causes electrical short-circuiting and current leakage

Engineering Contradiction:

Improveelectrical insulation reliabilityVSAvoidmoisture absorption

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

A resin-coated fibrous insulating material is introduced as an intermediary between the metallic members and the inorganic mat member. The resin coating acts as a moisture barrier that prevents moisture from reaching the inorganic mat member, thereby maintaining electrical insulation reliability even in humid environments while allowing the inorganic mat member to retain its insulation function

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The insulating structure uses a composite arrangement combining resin-coated fibrous material and inorganic mat member. This composite structure leverages the moisture resistance of the resin coating and the insulation properties of the inorganic mat member to achieve both moisture protection and electrical insulation simultaneously

Inventive Principle:

Principle #40Composite materials

2Temperature

If voltage is applied to heat the honeycomb structure, then heating capability is improved, but current leakage occurs due to moisture in insulating materials

Engineering Contradiction:

Improveheating capabilityVSAvoidcurrent leakage

Core Design Contradiction:

TemperatureVSLoss of energy

Solution Approach 1:

The resin-coated fibrous insulating material serves as a protective intermediary that prevents moisture-induced current leakage while allowing the voltage application system to function. This enables effective resistance heating of the honeycomb structure by preventing electrical short-circuits through the insulating layers

Inventive Principle:

Principle #24Intermediary (Mediator)

3Reliability

If thick insulating layers are used to prevent short-circuiting, then insulation reliability improves, but device complexity and space requirements increase

Engineering Contradiction:

Improveelectrical insulation reliabilityVSAvoidinsulating layer structure

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The resin coating forms a thin protective film on the fibrous insulating material. This thin resin layer provides effective moisture barrier protection without requiring thick insulating layers, thereby maintaining device compactness while ensuring insulation reliability

Inventive Principle:

Principle #30Flexible shells and thin films

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 restricts current leakage and ensures appropriate resistance heating of the honeycomb structure, maintaining insulation properties and preventing overheating, even in humid environments.

Implementation Method 1

The insulating layer have a thickness of about 20 μm to about 400 μm and is provided at at least one of a first part which is an inner surface of the first cylindrical metallic member, a second part between an outer surface of the first cylindrical metallic member and the inorganic mat member, and a third part between an inner surface of the second cylindrical metallic member and the inorganic mat member

Methodology Applied

Scientific EffectElectrical insulation: Electrical Resistance

Implementation Method 2

Conventional exhaust gas processing devices with honeycomb structures face issues of electrical short-circuiting and inadequate heating due to moisture absorption by inorganic mat members

Methodology Applied

Scientific EffectMoisture absorption: Absorption (physical)

Implementation Method 3

An electrode for applying a voltage is provided in the honeycomb structure and electrical power is applied to the honeycomb structure to heat the honeycomb structure

Methodology Applied

Scientific EffectJoule heating: Joule Heating

Data Source

PatentUS8871152B2Exhaust gas processing device

Publication Date: 2014.10.28 IBIDEN CO LTD

AI summary

An exhaust gas processing device includes a first cylindrical metallic member, an inorganic mat member, a second cylindrical metallic member, and an insulating layer. The inorganic mat member is wound around an outer periphery of the first cylindrical metallic member. The second cylindrical metallic member accommodates the first cylindrical metallic member around which the inorganic mat member is wound. The insulating layer have a thickness of about 20 μm to about 400 μm and is provided at at least one of a first part which is an inner surface of the first cylindrical metallic member, a second part between an outer surface of the first cylindrical metallic member and the inorganic mat member, and a third part between an inner surface of the second cylindrical metallic member and the inorganic mat member.