Honeycomb Heating Device Connecting Body Thermal Stress Management
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing honeycomb heating devices for exhaust gas purification face issues with durability due to temperature changes and moisture absorption, leading to potential electrical failures and structural breakage, especially in high-temperature environments.
Innovation Solution
A honeycomb type heating device with a connecting body having a cross-sectional area of 10.0 to 30.0 mm² and a thermal expansion coefficient higher than the honeycomb substrate by 3.0×10⁻⁶/°C, featuring a stress-relieving design such as notches or bent portions, and made of materials like Ni or stainless steel, to manage thermal stress and prevent breakage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a connecting body with large cross-sectional area is used to prevent melting, then heat resistance is improved, but rigidity increases causing stress on honeycomb structure
Solution Approach 1:
The patent optimizes the cross-sectional area of the connecting body to a specific range (10.0 to 30.0 mm²) to balance heat resistance and rigidity. This parameter change prevents melting while avoiding excessive stress on the honeycomb structure during thermal expansion.
Solution Approach 2:
The connecting body is designed with a thermal expansion coefficient higher than the honeycomb substrate by 3.0×10⁻⁶/°C or more. This allows the connecting body to expand more during heating, accommodating thermal expansion differences and reducing stress on the honeycomb structure.
2Stability of the object's composition
If the cross-sectional area of the connecting body is increased to prevent melting, then thermal stability is improved, but the honeycomb structure is strongly restrained causing breakage
Solution Approach 1:
The patent specifies a cross-sectional area range (10.0 to 30.0 mm²) that provides sufficient thermal stability while limiting excessive rigidity. This optimized parameter ensures the connecting body remains stable at high temperatures without overly restraining the honeycomb structure during thermal expansion.
Solution Approach 2:
By designing the connecting body with a higher thermal expansion coefficient than the honeycomb substrate, the system accommodates differential thermal expansion. The connecting body expands more during heating, preventing excessive restraint and potential breakage of the honeycomb structure.
3Use of energy by stationary object
If heat-insulation material is used around the honeycomb structure, then thermal insulation is improved, but moisture absorption causes electrical leakage
Solution Approach 1:
The patent introduces a heat-resistant insulating member as an intermediary between the heat-insulation material and the honeycomb structure/heaters. This mediator prevents moisture from reaching the electrical components while maintaining thermal insulation performance, thus preventing electrical leakage.
Solution Approach 2:
The patent separates the heat-insulation material from direct contact with electrical components by introducing a heat-resistant insulating member. This extraction of the moisture-absorbing material from the electrical system eliminates the risk of electrical leakage while preserving thermal insulation.
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 device effectively prevents melting and breakage of the honeycomb structure by managing thermal expansion and stress, ensuring efficient heating of the catalyst to activation temperature for exhaust gas purification.
Implementation Method 1
a thermal expansion coefficient of the connecting body is larger than a thermal expansion coefficient of the honeycomb substrate by 3.0×10−6/° C. or more
Implementation Method 2
each of the heaters is a resistance-heating type heater which generates heat by energization
Data Source
AI summary
A honeycomb type heating device includes a pillar-shaped honeycomb substrate having a partition wall defining and forming a plurality of cells and a circumferential wall surrounding the partition wall; a plurality of heaters adjacent to each other arranged on a circumferential surface of a circumferential wall in the circumferential direction of the circumferential surface; a connecting body arranged in the circumferential direction of the circumferential surface and electrically connecting the plurality of heaters; and a metal case housing the honeycomb substrate, the plurality of heaters, and the connecting body. Each heater is a resistance-heating type heater, the cross-sectional area of the connecting body in a cross section perpendicular to the circumferential direction of the circumferential surface is 10.0 to 30.0 mm2, and the thermal expansion coefficient of the connecting body is higher than the thermal expansion coefficient of the honeycomb substrate by 3.0×10−6/° C. or more.