Plugged Honeycomb Filter with Penetrating Trapping Layer

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Solution Overview

Problem

Conventional plugged honeycomb structures face challenges in achieving high heat capacity, low initial pressure loss, and small increase in pressure loss during particulate matter deposition while maintaining high trapping efficiency, due to issues with slurry penetration into the partition wall pores and insufficient suppression of initial pressure loss.

Innovation Solution

A plugged honeycomb structure with a pillar-shaped honeycomb substrate, a plugging portion at the open ends of cells, and a porous trapping layer formed by cordierite as the main phase, where the trapping layer penetrates into the partition wall base material pores with a thickness of 0 to 20 μm, enhancing thermal shock resistance and reducing initial pressure loss.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If the porosity of the partition wall is lowered to increase the heat capacity of the honeycomb filter, then the heat capacity is improved and temperature rise is suppressed, but the pressure loss during deposition of particulate matter increases

Engineering Contradiction:

Improveheat capacityVSAvoidpressure loss

Core Design Contradiction:

Quantity of substanceVSLoss of energy

Solution Approach 1:

The partition wall is segmented into two distinct layers: a porous partition wall base material and a trapping layer with smaller pores. This segmentation allows each layer to perform its specialized function - the base material provides heat capacity while the trapping layer captures particulate matter, resolving the contradiction between heat capacity and pressure loss.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different regions of the partition wall structure are assigned different properties. The base material has higher porosity for heat capacity, while the trapping layer has lower porosity for particle capture. This local differentiation of properties allows simultaneous optimization of both heat capacity and pressure loss characteristics.

Inventive Principle:

Principle #3Local quality

2Reliability

If a porous membrane with small particle diameter ceramic particles is formed at the surface of the porous partition wall to suppress penetration of particulate matter, then the trapping efficiency is improved, but the slurry penetrates into the pores of the partition wall and initial pressure loss increases

Engineering Contradiction:

Improvetrapping efficiencyVSAvoidinitial pressure loss

Core Design Contradiction:

ReliabilityVSLoss of energy

Solution Approach 1:

The trapping layer is applied as a preliminary coating on the surface of the porous partition wall base material before the filter is put into service. This preliminary action creates a protective barrier that prevents particulate matter from penetrating deep into the partition wall pores, thereby maintaining low initial pressure loss while ensuring high trapping efficiency.

Inventive Principle:

Principle #10Preliminary action

3Reliability

If a trapping layer is added to trap particulate matter at the surface of the partition wall, then the trapping efficiency is improved and pressure loss increase during deposition is suppressed, but the device complexity increases

Engineering Contradiction:

Improvetrapping efficiencyVSAvoidstructure complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The trapping layer and the partition wall base material are merged into a single integrated structure where the trapping layer is formed directly on the surface of the base material. This merging approach achieves high trapping efficiency while minimizing structural complexity by combining two functions into one unified component.

Inventive Principle:

Principle #5Merging (Combining)

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 solution provides a honeycomb filter with improved heat capacity, reduced initial pressure loss, and efficient particulate matter trapping, while preventing excessive temperature rise and breakage, thus optimizing filtration performance.

Implementation Method 1

a part of the trapping layer penetrating into pores formed at the partition wall base material has a thickness of 0 to 20 μm

Methodology Applied

Scientific EffectCapillary action: Capillary Action

Implementation Method 2

the partition wall base material is formed by a base material porous body including cordierite as a main phase... increase the heat capacity of the honeycomb filter... internal temperature of the honeycomb filter rises

Methodology Applied

Scientific EffectThermal energy absorption: Heat Sink

Data Source

PatentUS10040017B2Plugged honeycomb structure

Publication Date: 2018.08.07 NGK INSULATORS LTD

AI summary

A plugged honeycomb structure includes: a pillar-shaped honeycomb substrate having a partition wall base material that defines a plurality of cells serving as a through channel of fluid; a plugging portion disposed at open ends of predetermined cells at an inflow-side end face of fluid and at open ends of residual cells at an outflow-side end face of fluid; and a porous trapping layer disposed at least at a surface of the partition wall base material of the residual cells. The partition wall base material is formed by a base material porous body including cordierite as a main phase, the trapping layer is formed by a trapping layer porous body including cordierite as a main phase, and a part of the trapping layer penetrating into pores formed at the partition wall base material has a thickness of 0 to 20 μm.