Honeycomb Structured Body Peripheral Irregularities Thermal Shock
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Solution Overview
Problem
Conventional honeycomb structured bodies for exhaust gas conversion face challenges in achieving optimal contact probability between exhaust gas and catalyst noble metals and NOx-storage agents, leading to inadequate converting performance, and they are prone to thermal shock and damage due to irregularities on the peripheral face.
Innovation Solution
A honeycomb structured body with irregularities formed on its peripheral face, comprising inorganic particles and fibers, where the size and distribution of these irregularities are controlled to enhance strength and durability, and a sealing material is used to bind honeycomb units together, forming a pillar-shaped block with specific cross-sectional shapes to improve thermal shock resistance and push-out strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If irregularities are formed on the peripheral face to improve holding force, then the holding force increases, but the honeycomb structured body becomes prone to thermal shock and cracking
Solution Approach 1:
The patent applies local quality by forming irregularities only on specific peripheral portions of the honeycomb structured body rather than uniformly across the entire periphery. This localized approach concentrates the holding force enhancement where most needed while preserving thermal shock resistance in other areas. The irregularities are strategically positioned to improve insertion holding force without compromising overall structural integrity.
Solution Approach 2:
The patent employs composite materials by combining the honeycomb structured body with a heat-resistant adhesive material that has thermal shock resistance equal to or higher than the honeycomb body itself. This composite structure allows the irregularities to provide enhanced holding force while the heat-resistant adhesive compensates for and protects against thermal shock susceptibility, resolving the contradiction between holding force and thermal shock resistance.
2Productivity
If the cross-sectional area is enlarged to improve converting performance, then the contact probability increases, but the push-out strength decreases
Solution Approach 1:
The patent applies asymmetry by forming irregularities with asymmetric shapes on the peripheral face of the honeycomb structured body. These asymmetric irregularities include protrusions and recesses that interlock with the insertion member, creating mechanical engagement that enhances push-out strength. The asymmetric geometry provides increased surface area for contact and interlocking, allowing the structure to maintain high converting performance while compensating for the reduced push-out strength associated with larger cross-sectional areas.
3Quantity of substance
If inorganic fibers are added to increase specific surface area, then the catalytic performance improves, but the manufacturing complexity increases
Solution Approach 1:
The patent merges the function of inorganic fibers with the heat-resistant adhesive material by incorporating the fibers into the adhesive composition. This combination allows the adhesive to simultaneously provide structural bonding and contribute to the specific surface area through the embedded fibers. The merging of these functions simplifies manufacturing by eliminating the need for separate fiber placement steps while achieving the desired catalytic performance enhancement.
Data Source
AI summary
A honeycomb structured body comprising a pillar-shaped honeycomb block including a honeycomb unit in which a number of cells are longitudinally placed in parallel with a cell wall therebetween. The honeycomb unit comprising inorganic particles, as well as inorganic fibers and/or whiskers, and the inorganic fibers and/or whiskers increase a specific surface area of the honeycomb unit. A sealing material provided on a peripheral portion of the honeycomb block. Irregularities are formed on the peripheral face of the honeycomb structured body and the pillar-shaped honeycomb block. A least square curve is obtained by a least square method on the basis of points comprising the contour of a cross-section perpendicular to the longitudinal direction of the honeycomb structured body and the honeycomb block.