Honeycomb Structure with Selective Catalyst Distribution
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Solution Overview
Problem
Conventional honeycomb structures for exhaust gas purification face inefficiencies in particulate burning and regeneration due to uneven catalyst distribution and increased pressure loss, leading to higher costs and reduced service life.
Innovation Solution
A pillar-shaped honeycomb structure with large-volume and small-volume cells, where the catalyst is selectively supported on cell walls, particularly on large-volume cells in higher amounts, to increase contact points with particulates while minimizing overall catalyst usage and maintaining a high aperture ratio, thereby enhancing burning efficiency and reducing pressure loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the catalyst is uniformly distributed on all cell walls, then the catalyst coverage is comprehensive, but the burning efficiency is insufficient and pressure loss increases
Solution Approach 1:
The patent applies local quality by concentrating the catalyst on specific cell walls (inlet-side cell walls and outlet-side cell walls of large-volume cells) rather than uniformly distributing it across all cell walls. This localized catalyst placement creates high-density catalyst zones where they are most needed for burning particulates, while leaving other areas catalyst-free to maintain open flow paths and reduce pressure loss.
2Productivity
If the catalyst amount is increased to improve burning efficiency, then more particulates can be burned, but the cost increases and service life decreases due to faster catalyst deactivation
Solution Approach 1:
The patent reduces total catalyst consumption by applying catalyst only to specific cell walls where it provides maximum benefit. The catalyst is concentrated on inlet-side cell walls to burn particulates early in the flow path, and on outlet-side cell walls of large-volume cells to burn remaining particulates. This localized approach achieves high burning efficiency with less total catalyst, extending service life and reducing cost.
Solution Approach 2:
The patent segments the catalyst distribution into distinct zones: inlet-side cell walls, outlet-side cell walls of large-volume cells, and intermediate cell walls. This segmentation allows the catalyst to be strategically placed in zones where it most effectively burns particulates at different stages of the flow path, optimizing both efficiency and catalyst utilization.
3Quantity of substance
If the aperture ratio is reduced to increase catalyst support area, then more catalyst can be supported, but the pressure loss increases
Solution Approach 1:
The patent resolves this contradiction by applying catalyst locally to specific cell walls rather than requiring increased catalyst support area. The selective catalyst placement on inlet-side and outlet-side cell walls achieves effective catalyst utilization without needing to reduce the aperture ratio, thereby maintaining low pressure loss while still providing sufficient catalyst for burning particulates.
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 structured honeycomb efficiently burns and eliminates particulates with reduced pressure loss and extended service life by optimizing catalyst distribution and aperture ratios, improving both burning efficiency and regeneration rates.
Implementation Method 1
a catalyst being supported on the cell wall... the catalyst substance is distributed so as to be supported on the flow-in side of exhaust gases passing through the cell wall
Implementation Method 2
particulates in exhaust gases discharged from the internal combustion system are captured by the cell walls upon passing through the honeycomb structure so that the exhaust gases are purified
Data Source
AI summary
A honeycomb structure includes large-volume cells and small-volume cells with a cell wall therebetween; a plug sealing at either one of end portions of the cells; and a catalyst supported on the cell wall. The large-volume cell has a larger cross-sectional area perpendicular to its longitudinal direction than that of the small-volume cell. The large-volume cell is sealed at one end portion of the honeycomb structure, while the small-volume cell is sealed at the other end portion of the honeycomb structure. The catalyst is supported only on the cell walls forming the large-volume cells, or on both of the cell walls forming said large-volume cells and the cell walls forming said small-volume cells. An amount of the catalyst supported on the cell walls forming the large-volume cells is larger per unit volume than that on the cell walls forming the small-volume cells.