Honeycomb Structure Outer Wall Protrusions Bonding
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Solution Overview
Problem
Honeycomb structures formed with silicon carbide suffer from thermal shock and separation issues due to repeated heating and cooling during particulate matter regeneration, leading to detachment of segments and reduced isostatic strength.
Innovation Solution
The honeycomb structure features thicker outer peripheral walls with protruding and depressed portions, increasing bonding strength with the bonding member and enhancing isostatic strength, while maintaining effective particulate matter trapping and thermal capacity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If honeycomb segments are bonded with a bonding material at side faces, then the honeycomb structure can be assembled, but detachment occurs due to repeated heating and cooling causing separation
Solution Approach 1:
The outer peripheral wall is divided into multiple protruding portions that contact the bonding member at multiple discrete locations, distributing thermal stress and preventing detachment during repeated heating and cooling cycles
Solution Approach 2:
The outer peripheral wall features an asymmetric profile with protruding portions that create unequal contact zones with the bonding member, optimizing the bonding interface to resist both tensile and compression stresses during thermal cycling
2Volume of stationary object
If the honeycomb structure is made larger to improve filtration capacity, then more particulate matter can be trapped, but thermal shock causes defects
Solution Approach 1:
The large honeycomb structure is divided into multiple smaller segments that are bonded together, allowing each segment to better withstand thermal shock while maintaining the overall large volume needed for high filtration capacity
Solution Approach 2:
The structure combines ceramic honeycomb segments with a bonding material that has appropriate thermal expansion properties, creating a composite structure that resists thermal shock while maintaining structural integrity at large sizes
3Productivity
If thin partition walls are used to increase cell density, then more cells can be packed, but isostatic strength decreases
Solution Approach 1:
The outer peripheral wall thickness is increased in the radial dimension while maintaining thin partition walls in the axial dimension, providing structural strength without reducing cell density
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 design inhibits separation of honeycomb segments, improves isostatic strength, and suppresses maximum temperature during regeneration, thereby extending the regeneration limit and maintaining efficient particulate matter trapping.
Implementation Method 1
The bonding of the segments is performed by the use of a bonding material, which is applied on a side face (outer peripheral wall) of a predetermined segment, and a plurality of segments are bonded together at the side faces to obtain a honeycomb structure where a plurality of segments are bonded by means of the bonding member
Implementation Method 2
Since silicon carbide has relatively large thermal expansion coefficient, a honeycomb structure formed with silicon carbide as the framework may cause a defect due to thermal shock upon use if the size is large
Implementation Method 3
combustion of trapped particulate matter (regeneration) is repeated
Data Source
Figure 1~2
Figure 3~4
Figure 5
AI summary
There is provided a honeycomb structure 100 comprising a plurality of honeycomb segments 4 having porous partition walls 2 separating and forming a plurality of cells 1 and an outer peripheral wall 3 located in the outermost periphery and being thicker than the partition walls 2, first cells 1a each open in an end portion on one side and plugged in the other end portion on the other side and second cells 1b each plugged in the end portion on the one side and open in the other end portion on the other side being alternately disposed with the first cells 1a having an area larger than that of the second cells 1b in a cross section perpendicular to the central axial direction, and the outer peripheral wall 3 having protruding portions along an external shape of the first cells 1a and depressed portions 1b along an external shape of the second cells 1b. The honeycomb segments 4 are bonded to each other with a bonding member.