Plugged Honeycomb Segment With Localized Wall Thickness
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Solution Overview
Problem
Conventional plugged honeycomb structures used in exhaust gas purifying filters face issues with high pressure loss and catalyst clogging, especially at the outermost circumference cells, which affects their purifying performance and mechanical strength.
Innovation Solution
A plugged honeycomb segment with a quadrangular prism shape and specific porosity, featuring hexagonal and square cells arranged in a repeating pattern, where the outermost circumferential wall thickness is optimized to reduce pressure loss and prevent catalyst clogging, while maintaining excellent isostatic strength and bonding strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the size of open ends of cells at the outermost circumference is reduced to maintain structural integrity, then the mechanical strength is improved, but the pressure loss increases and catalyst clogging occurs
Solution Approach 1:
The patent applies different thickness values for the outermost circumferential wall at different locations: a first thickness value for walls contacting incomplete cells and a second thickness value for walls contacting complete cells. This local differentiation allows the structure to maintain strength where needed while preserving adequate open end sizes for flow performance, thereby resolving the contradiction between mechanical strength and pressure loss.
2Stability of the object's composition
If the size of open ends of cells at the outermost circumference is reduced, then the structural integrity is improved, but the catalyst loading uniformity deteriorates and clogging increases
Solution Approach 1:
By specifying different thickness values for the outermost circumferential wall at different locations (first thickness for incomplete cells, second thickness for complete cells), the patent ensures that complete cells maintain adequate open end sizes for uniform catalyst loading while incomplete cells have reduced thickness for structural integrity, thus resolving the contradiction between structural integrity and catalyst loading uniformity.
3Loss of energy
If the porosity of partition walls is increased to reduce pressure loss, then the fluid flow performance is improved, but the mechanical strength and isostatic strength decrease
Solution Approach 1:
The patent specifies a porosity range of 30-70% for the partition walls, optimizing this parameter to balance pressure loss reduction with maintenance of mechanical strength. This parameter optimization resolves the contradiction between fluid flow performance and structural strength.
Data Source
AI summary
A plugged honeycomb segment includes a honeycomb segment having a quadrangular prism shape which includes porous partition walls arranged to surround a plurality of cells and an outermost circumferential wall, and a plugging portion, wherein a porosity of the partition walls is 30 to 70%, in a cross section orthogonal to the cell extending direction, an inflow cell surrounded by the partition walls is a hexagon, and an outflow cell is a square, one outflow cell is surrounded by four inflow cells, the cell located at the outermost circumference includes a complete cell and an incomplete cell, and a thickness of the outermost circumferential wall in contact with the incomplete cell (T1), a thickness of the outermost circumferential wall in contact with the complete cell (T2), and a thickness of the partition walls (WT), satisfy 0.200 mm<T1<T2−(½×WT) and T2≤0.700 mm.