Segmented Heat Insulation for Exhaust Junction Pipe

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Solution Overview

Problem

The existing heat insulating structure for exhaust junction pipes is complex, with a large cover and unnecessary heat insulation in areas other than the exhaust junction pipe, leading to potential breakage and inefficiency due to differing heat expansion rates and mechanical vibrations.

Innovation Solution

A simplified heat insulating structure for exhaust junction pipes, where a first heat insulation portion covers the short branch part of the exhaust gas passage and a second heat insulation portion covers the merged branch part, using outer cylinders and heat insulating materials like grass wool, allowing for reduced size and firm attachment without considering heat expansion of other branch parts.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If a large cover is used to cover most of the exhaust junction pipe, then heat insulation is improved, but device complexity and attachment difficulty increase due to differing heat expansion rates between the cover and pipe

Engineering Contradiction:

Improveheat insulationVSAvoidattachment structure

Core Design Contradiction:

TemperatureVSDevice complexity

Solution Approach 1:

The exhaust junction pipe is divided into multiple branch parts (first branch part, second branch part, third branch part) corresponding to different exhaust gas passages. Heat insulation is applied selectively to specific branch parts rather than covering the entire pipe, reducing the size and weight of the cover while maintaining necessary thermal insulation for catalytic activity.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Heat insulation is provided locally only to the first branch part and third branch part where it is necessary for maintaining catalytic temperature. The second branch part forming the long exhaust gas passage is left uncovered, eliminating unnecessary heat insulation and reducing overall device complexity.

Inventive Principle:

Principle #3Local quality

2Ease of manufacture

If the cover is fixed at the upstream-side, then attachment is simplified, but reliability decreases due to breakage caused by difference in heat expansion between cover and pipe

Engineering Contradiction:

Improveattachment simplicityVSAvoidresistance to breakage

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The cover is divided into multiple sections corresponding to different branch parts. Each section can expand and contract independently with temperature changes, reducing stress concentration and preventing breakage while maintaining simple attachment methods.

Inventive Principle:

Principle #1Segmentation

3Temperature

If a double-walled pipe structure is used, then heat insulation is improved, but manufacturing complexity and cost increase

Engineering Contradiction:

Improveheat insulationVSAvoidmanufacturing complexity

Core Design Contradiction:

TemperatureVSEase of manufacture

Solution Approach 1:

Instead of using a complex double-walled pipe structure for the entire exhaust system, heat insulation is segmented and applied only to specific branch parts (first and third branch parts) using simpler insulation materials and methods, reducing manufacturing complexity while maintaining necessary thermal insulation.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Heat insulation is applied locally to specific areas where it is necessary for maintaining catalytic temperature, rather than using a universal double-walled structure throughout the entire exhaust system, thereby reducing manufacturing complexity and cost.

Inventive Principle:

Principle #3Local quality

4Temperature

If heat insulation is applied to all branch parts, then heat insulation is improved, but weight and material usage increase unnecessarily

Engineering Contradiction:

Improveheat insulationVSAvoidcover weight

Core Design Contradiction:

TemperatureVSWeight of moving object

Solution Approach 1:

Heat insulation is applied locally only to the first branch part and third branch part where it is necessary for maintaining catalytic temperature. The second branch part forming the long exhaust gas passage is left uncovered, eliminating unnecessary material usage and reducing overall weight.

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 achieves equivalent or superior heat insulation effects while reducing the size and weight of the exhaust junction pipe, maintaining catalytic activity temperatures and lowering manufacturing costs by eliminating the need for a double-walled structure and reducing material usage.

Implementation Method 1

a heat insulating portion 4 that covers and provides heat insulation for at least a portion of one branch part 31 of branch parts that are branched in the exhaust junction pipe 3

Methodology Applied

Scientific EffectThermal insulation: Thermal Insulation

Implementation Method 2

using outer cylinders and heat insulating materials like grass wool

Methodology Applied

Scientific EffectThermal resistance: Thermal Insulation

Data Source

PatentUS10180099B2Heat insulating structure for exhaust junction pipe

Publication Date: 2019.01.15 FUTABA IND CO LTD

AI summary

A heat insulating structure for an exhaust junction pipe to be disposed in an area in which exhaust gas passages having different respective lengths are merged together comprises a first heat insulation portion that covers and provides heat insulation for at least a portion of one branch part of branch parts that are branched in the exhaust junction pipe; the one branch part forms one exhaust gas passage in a not-yet-merged state of the exhaust gas passages, and forms the one exhaust gas passage having a short length.