Honeycomb Filter Plugging Length Optimization
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Solution Overview
Problem
Conventional honeycomb filters face challenges in achieving satisfactory exhaust gas purification performance when loaded with a catalyst, as they tend to have plugging portions fall off easily and lack sufficient isostatic strength, especially during the canning process.
Innovation Solution
A honeycomb filter design featuring a pillar-shaped structure with porous partition walls and plugging portions, where the central plugging portions have a shorter length than the circumferential ones, and a specific area ratio, enhancing the filter's porosity and isostatic strength to prevent plugging portion detachment and improve catalyst activation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the honeycomb filter uses conventional uniform plugging portions, then the structure is simple, but the plugging portions easily fall off from cells during canning
Solution Approach 1:
The patent applies different plugging lengths to different regions: central plugging portions have length L1 (3-6mm) while circumferential plugging portions have length L2 (7-9mm). This local differentiation ensures that plugging portions in high-stress circumferential regions are longer and more secure, while central regions require shorter plugging portions, thereby preventing plugging portion detachment without requiring a completely different structure throughout.
Solution Approach 2:
The honeycomb filter structure is divided into central region and circumferential region with distinct plugging portion characteristics. This segmentation allows each region to be optimized independently for its specific functional requirements, improving overall reliability while maintaining manageable structural complexity.
2Loss of energy
If the honeycomb filter uses thinner walls and higher porosity to reduce pressure loss, then fuel economy improves, but isostatic strength decreases
Solution Approach 1:
The patent optimizes specific parameters: porosity is set to 40-60% and partition wall thickness to 0.15-0.30mm. These parameter changes achieve the right balance between maintaining low pressure loss (improved fuel economy) and ensuring sufficient isostatic strength to withstand canning compression forces.
3Reliability
If the honeycomb filter is canned with high compression pressure, then the filter is securely held, but plugging portions are damaged or fall off
Solution Approach 1:
The circumferential plugging portions are designed with greater length (L2 = 7-9mm) than central plugging portions (L1 = 3-6mm) to provide beforehand cushioning against the high compression pressures encountered during canning. This preemptive design ensures that plugging portions in the vulnerable circumferential region are already reinforced before canning occurs, preventing damage and detachment.
4Productivity
If the honeycomb filter uses conventional plugging lengths, then manufacturing is simple, but exhaust gas purification performance is insufficient
Solution Approach 1:
Different plugging lengths are assigned to different regions to optimize purification performance: shorter central plugging portions (L1) allow better gas flow through the center, while longer circumferential plugging portions (L2) ensure secure sealing at the edges. This local quality differentiation improves overall purification efficiency without requiring completely complex manufacturing processes.
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 enhances exhaust gas purification performance, suppresses plugging portion detachment, and improves isostatic strength, ensuring the filter's integrity under compression, thus meeting the demands for improved fuel economy and environmental compliance.
Implementation Method 1
the porous partition walls of the honeycomb structure function as filters that trap the particulate matter in an exhaust gas
Implementation Method 2
porous plugging portions provided either at the ends on the inflow end face side of the cells or at the ends on the outflow end face side of the cells
Data Source
AI summary
A honeycomb filter includes a pillar-shaped honeycomb structure having porous partition walls provided, surrounding a plurality of cells which serve as fluid through channels extending from an inflow end face to an outflow end face, and porous plugging portions provided either at the ends on the inflow end face or the outflow end face of the cells, wherein the plugging portions are composed of a porous material, the honeycomb structure has a central region and a circumferential region and a ratio of an area of the circumferential region with respect to that of the central region ranges from 0.1 to 0.5, and a plugging length L1 in the cell extending direction of a central plugging portion in the central region is smaller than a plugging length L2 of a circumferential plugging portion in the circumferential region, L1 ranges from 3 to 6 mm, and L2 from 7 to 9 mm.