Honeycomb Structure Pore Diameter Control for Diesel Filter Pressure Loss

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Solution Overview

Problem

Conventional honeycomb structures used in diesel particulate filters face challenges in achieving both high particulate matter collection efficiency and low pressure loss, as particulate matter penetration into porous partition walls leads to increased pressure loss.

Innovation Solution

A honeycomb structure with partition walls having an average pore diameter of 5.0 to 30.0 µm and a surface open area ratio of 0.05 to 0.45, made from materials like silicon carbide, alumina, or cordierite, with a single layer structure and specific manufacturing methods involving plate-like raw materials to control pore sizes and porosity, reducing pressure loss while maintaining collection efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If porous partition walls are used to enable fluid flow through the honeycomb structure, then the honeycomb structure can function as a filter, but particulate matter penetrates into the partition walls causing pressure loss to rapidly increase

Engineering Contradiction:
Improvefiltering functionVSAvoidpressure loss
Core Design Contradiction:
ReliabilityVSLoss of energy

Solution Approach 1:

The partition walls are designed with controlled porosity (10-50%) and specific pore diameter (5-30 μm) to balance filtration capability and pressure loss. The porous structure allows fluid passage while the controlled pore characteristics prevent excessive PM penetration that would cause rapid pressure loss increase.

Inventive Principle:
Principle #31Porous materials

Solution Approach 2:

The invention optimizes specific parameters including pore diameter (5-30 μm), porosity (10-50%), and surface open area ratio (0.05-0.45) to achieve the desired balance between filtration performance and pressure loss characteristics.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If the pore size in partition walls is reduced to improve particulate matter collection efficiency, then collection performance increases, but pressure loss during fluid flow increases

Engineering Contradiction:
Improvecollection efficiencyVSAvoidpressure loss
Core Design Contradiction:
ReliabilityVSLoss of energy

Solution Approach 1:

The invention identifies an optimal parameter range for pore diameter (5-30 μm) that balances collection efficiency and pressure loss. This parameter optimization allows the partition walls to capture particulate matter effectively while maintaining acceptable pressure loss characteristics during fluid flow.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The partition walls are made from composite ceramic materials that provide both the necessary porosity for filtration and sufficient mechanical strength to maintain structural integrity while resisting pressure loss.

Inventive Principle:
Principle #40Composite materials

3Loss of energy

If a collecting layer is disposed on the surfaces of partition walls to prevent PM penetration, then pressure loss increase is suppressed, but the structure complexity and manufacturing difficulty increase

Engineering Contradiction:
Improvepressure loss suppressionVSAvoidstructure complexity
Core Design Contradiction:
Loss of energyVSDevice complexity

Solution Approach 1:

The invention extracts the filtration function from a separate collecting layer and integrates it directly into the partition wall structure itself. By forming the partition walls with controlled pore characteristics, the filtration capability is built-in, eliminating the need for additional collecting layers and reducing overall structure complexity.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The invention merges the structural function of partition walls with the filtration function of collecting layers into a single integrated component. The partition walls simultaneously provide structural support and filtration capability through their controlled porosity and pore diameter, simplifying the overall filter structure.

Inventive Principle:
Principle #5Merging (Combining)

4Loss of energy

If high porosity ceramic material is used to reduce pressure loss, then fluid flow resistance decreases, but manufacturing precision and control over pore characteristics become more difficult

Engineering Contradiction:
Improvepressure lossVSAvoidpore characteristic control
Core Design Contradiction:
Loss of energyVSManufacturing precision

Solution Approach 1:

The invention establishes specific parameter ranges for porosity (10-50%) and pore diameter (5-30 μm) that can be reliably controlled during manufacturing. These parameter specifications provide clear manufacturing targets that balance pressure loss reduction with achievable manufacturing precision.

Inventive Principle:
Principle #35Parameter changes

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 proposed honeycomb structure effectively collects particulate matter with low pressure loss, as the controlled pore sizes and material composition minimize particulate matter deposition and pressure drop, enhancing both collection efficiency and flow resistance.

Implementation Method 1

partition walls with which a plurality of cells are formed to become through channels of a fluid... the partition walls have a single layer structure... average pore diameter of the pores formed in the partition walls

Methodology Applied
Scientific EffectPorosity: Porosity

Data Source

PatentEP2644245B1Honeycomb structure and manufacturing method of the same
Publication Date: 2020.04.22 NGK INSULATORS LTD
  • EP2644245B1 patent drawingFigure 1~2
  • EP2644245B1 patent drawingFigure 3~4
  • EP2644245B1 patent drawingFigure 5~6

AI summary

There is disclosed a honeycomb structure which has an excellent collecting performance of a particulate matter and in which a pressure loss during flowing of a fluid through the honeycomb structure is low. The honeycomb structure includes a honeycomb base material having porous partition walls with which a plurality of cells are formed to become through channels of a fluid, a value of a ratio of an average open frontal area diameter of pores which are open in the surfaces of the partition walls to an average pore diameter of the pores formed in the partition walls is from 0.05 to 0.45, the partition walls have a single layer structure, and preferably, an open frontal area diameter of each of the pores which are open in the surfaces of the partition walls is from 0.5 to 10 µm.