Silicon Carbide Honeycomb Filter Peripheral Irregularities
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Solution Overview
Problem
Honeycomb filters with high thermal expansion materials like silicon carbide face displacement issues during thermal expansion and shrinkage due to conventional installation methods, leading to reduced mechanical strength and increased pressure loss, especially during regeneration processes.
Innovation Solution
A honeycomb filter design featuring a ceramic block with irregularities on its peripheral face, formed by projecting cell walls, and a sealing material layer applied along these irregularities to increase friction and prevent displacement, while maintaining porosity and mechanical strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a honeycomb filter is made from silicon carbide material, then high thermal resistance and chemical stability are achieved, but the high coefficient of thermal expansion causes displacement during thermal cycles
Solution Approach 1:
The invention applies different properties to different parts of the honeycomb filter. The peripheral face is given irregularities (protrusions and recesses) that are localized to the outer surface, while the internal honeycomb structure maintains its regular porous configuration. This local modification allows the filter to expand and contract thermally without displacing, as the irregularities create mechanical interlocking with the holding material.
Solution Approach 2:
The irregularities on the peripheral face include curved protrusions and recesses rather than sharp angles. These curved features better accommodate thermal expansion and contraction by providing gradual transitions that reduce stress concentration points, allowing the silicon carbide material to undergo thermal cycles without compromising positional stability.
2Shape
If a smoothing layer is formed to fill irregularities on the peripheral face, then a round pillar shape is achieved, but displacement occurs during thermal expansion and shrinkage
Solution Approach 1:
Instead of completely smoothing the peripheral face, the invention selectively preserves irregularities in the form of protrusions and recesses. These localized features maintain the overall round pillar shape while providing mechanical interlocking points that prevent displacement during thermal cycles, resolving the contradiction between aesthetic shape and functional stability.
3Stability of the object's composition
If the peripheral face is left with irregularities from cutting, then mechanical interlocking is achieved, but the surface is uneven and aesthetically undesirable
Solution Approach 1:
The invention transforms the sharp, uneven irregularities from cutting into controlled curved protrusions and recesses. This curvature maintains the mechanical interlocking function while creating a more uniform and aesthetically acceptable surface appearance, resolving the contradiction between functional roughness and visual uniformity.
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 design effectively prevents displacement of the honeycomb filter during thermal cycles and reduces pressure loss by enhancing friction between the filter and the holding material, while preventing PM leakage through the filter's surface.
Implementation Method 1
a sealing material layer formed on a peripheral face of the ceramic block
Data Source
AI summary
A honeycomb filter includes a ceramic block which includes a plurality of honeycomb fired bodies, an adhesive layer, and irregularities on a peripheral face of the ceramic block. Each honeycomb fired body has a longitudinal direction and cell walls extending along the longitudinal direction to define cells each sealed at either one of both ends of each of the cells. The honeycomb fired bodies include at least one of silicon carbide and silicon-containing silicon carbide. The adhesive layer is provided between the honeycomb fired bodies to connect the honeycomb fired bodies. The irregularities on the peripheral face include a projected portion formed by apart of the cell walls. A sealing material layer is provided on the peripheral face of the ceramic block in accordance with the irregularities on the peripheral face so that an outer peripheral surface of the honeycomb filter has surface irregularities thereon.