Honeycomb Structural Body with Radial Cell Density Gradient
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Honeycomb structural bodies used for exhaust gas purification from internal combustion engines face issues such as cell clogging, pressure loss, and inadequate thermal shock resistance due to imperfect cell shapes and uniformity in cell density, leading to suboptimal exhaust gas purification performance.
Innovation Solution
A honeycomb structural body design featuring cell density sections with different cell densities in a radial direction, separated by a boundary section with polygonal boundary cells and partition walls, where the average hydraulic diameter ratio of boundary cells to cell density section cells is greater than or equal to 1.25, preventing cell clogging and optimizing catalyst support and gas flow.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If cell density is increased to improve catalyst support and purification performance, then exhaust gas purification performance is improved, but pressure loss increases and thermal shock resistance deteriorates
Solution Approach 1:
The patent applies local quality by creating different cell density sections (first and second cell density sections) with distinct cell densities in different radial regions. The first cell density section has higher cell density for improved purification performance, while the second cell density section has lower cell density to reduce pressure loss and improve thermal shock resistance. This spatial differentiation allows each region to optimize for its specific functional requirements.
2Reliability
If cell density is increased to improve catalyst support, then exhaust gas purification performance is improved, but thermal shock resistance deteriorates
Solution Approach 1:
The patent applies local quality by creating different cell density sections (first and second cell density sections) with distinct cell densities in different radial regions. The first cell density section has higher cell density for improved purification performance, while the second cell density section has lower cell density to reduce pressure loss and improve thermal shock resistance. This spatial differentiation allows each region to optimize for its specific functional requirements.
3Speed
If partition wall thickness is decreased to reduce overall weight and improve thermal response, then thermal shock resistance is improved, but structural strength deteriorates
Solution Approach 1:
The patent applies local quality by creating different cell density sections (first and second cell density sections) with distinct cell densities in different radial regions. The first cell density section has higher cell density for improved purification performance, while the second cell density section has lower cell density to reduce pressure loss and improve thermal shock resistance. This spatial differentiation allows each region to optimize for its specific functional requirements.
Data Source
AI summary
In a cross section, perpendicular to an axial direction of a honeycomb structural body having partition walls and cells, a plurality of sections having a different cell density is formed from a central area toward an outer peripheral area, and a partition wall is formed between the sections adjacent to each other. The boundary section has boundary partition walls and plural boundary cells having a polygonal shape different in shape from the cells in the sections formed adjacent to the boundary section. The partition walls in the sections adjacent to the boundary section are connected by the boundary partition walls. A part of the boundary cell is surrounded by at least the boundary partition walls. A relationship of φ1/φ2≧1.25 is satisfied, where φ1 indicates an average hydraulic diameter of the boundary cells and φ2 indicates an average hydraulic diameter of the cells.