Honeycomb Filter Asymmetric Plugging for Erosion Resistance

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Solution Overview

Problem

Conventional honeycomb filters face issues with erosion due to foreign matter collisions and lack thermal shock resistance, leading to reduced filtering efficiency and potential damage from temperature gradients.

Innovation Solution

A honeycomb filter design featuring a pillar-shaped structure with porous partition walls and plugging portions composed of a porous material, where the central plugging portions have a longer length than the circumferential ones, providing enhanced erosion resistance and thermal shock resistance through optimized geometry and porosity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If plugging portions are designed for higher porosity to reduce pressure loss, then exhaust gas flow improves, but erosion resistance deteriorates as plugging portions are scraped off by foreign matters

Engineering Contradiction:

Improveexhaust gas flowVSAvoiderosion resistance

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The patent applies local quality by differentiating the plugging portions into central and circumferential regions with different properties. The central plugging portions have longer lengths and higher erosion resistance to withstand foreign matter collisions, while circumferential plugging portions have shorter lengths. This local differentiation allows the filter to maintain high porosity for gas flow while providing enhanced erosion resistance where needed most.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent employs asymmetry by making the central plugging portions longer than the circumferential plugging portions. This asymmetric design creates a gradient structure where the plugging length decreases from the center toward the circumference, optimizing both erosion resistance in the high-stress central region and overall gas flow through the filter.

Inventive Principle:

Principle #4Asymmetry

2Productivity

If partition wall thickness is reduced to lower pressure loss, then exhaust gas flow improves, but structural strength deteriorates

Engineering Contradiction:

Improveexhaust gas flowVSAvoidpartition wall strength

Core Design Contradiction:

ProductivityVSStrength

Solution Approach 1:

The patent applies parameter changes by optimizing the thickness of both partition walls and plugging portions within specific ranges. The partition wall thickness is controlled at 0.15mm to 0.30mm, and plugging portion lengths are precisely defined (central: 7-9mm, circumferential: 3-6mm). These parameter optimizations balance structural strength requirements with the need for low pressure loss and high gas flow.

Inventive Principle:

Principle #35Parameter changes

3Reliability

If plugging portions are made longer to improve erosion resistance, then foreign matter collision resistance improves, but pressure loss increases

Engineering Contradiction:

Improveerosion resistanceVSAvoidexhaust gas flow

Core Design Contradiction:

ReliabilityVSProductivity

Solution Approach 1:

The patent resolves this contradiction by applying local quality - making plugging portions longer only in the central region where erosion resistance is most critical, while keeping circumferential plugging portions shorter. This localized approach provides enhanced erosion resistance where foreign matter collisions are most frequent without excessively increasing overall pressure loss.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent applies partial action by providing enhanced plugging length only where needed (central region) rather than uniformly throughout. The central plugging portions are made longer than minimum requirements to ensure erosion resistance, while circumferential portions use shorter lengths, achieving the necessary protection without excessive material that would impede gas flow.

Inventive Principle:

Principle #16Partial or excessive action

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 significantly improves erosion resistance and thermal shock resistance, maintaining filtering efficiency and minimizing damage from regeneration processing, while maintaining high porosity for effective exhaust gas purification.

Implementation Method 1

the porous partition walls of the honeycomb structure function as filters that trap the particulate matter in an exhaust gas

Methodology Applied

Scientific EffectPhysical filtration: Filter (physical)

Implementation Method 2

the plugging portions are composed of a porous material

Methodology Applied

Scientific EffectPorosity: Porosity

Data Source

PatentUS11400441B2Honeycomb filter

Publication Date: 2022.08.02 NGK INSULATORS LTD

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, a plugging length L1 in the cell extending direction of a central plugging portion in the central region is larger than a plugging length L2 of a circumferential plugging portion in the circumferential region, L1 ranges from 7 to 9 mm, and L2 from 3 to 6 mm.