Honeycomb Filter Wave-Type Partition Walls

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Solution Overview

Problem

Conventional honeycomb filters face limitations in reducing pressure loss while increasing filter area and improving regeneration efficiency, with issues related to structural strength and complexity in manufacturing, leading to insufficient purification and regeneration performance.

Innovation Solution

A honeycomb filter design featuring cells with large and small sectional areas and wave-type cells with facing surfaces formed into a wavelike shape, along with plugging portions at open ends, to decrease pressure loss and enhance regeneration efficiency, while maintaining structural strength and simplifying the formation process.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If the partition walls are formed into a planar shape to decrease pressure loss, then the pressure loss is reduced, but the contact area between the partition walls and exhaust gas is insufficient, limiting purification performance improvement

Engineering Contradiction:
Improvepressure lossVSAvoidcontact area
Core Design Contradiction:
Loss of energyVSArea of stationary object

Solution Approach 1:

The partition walls are formed with a convex-concave curved shape instead of a planar shape. This curvature increases the surface area of the partition walls that come into contact with exhaust gas, thereby increasing the contact area without significantly increasing pressure loss. The curved surfaces allow for better gas flow accommodation while maintaining low resistance.

Inventive Principle:
Principle #14Spheroidality (Curvature)

Solution Approach 2:

The invention transitions from a two-dimensional planar partition wall to a three-dimensional convex-concave structure. By adding the dimensional aspect of curvature, the partition wall surface area is substantially increased, providing more contact area with exhaust gas while maintaining the overall compact structure and low pressure loss characteristics.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Area of stationary object

If the thicknesses of the partition walls are decreased and the number of cells are increased to increase contact area, then the contact area is increased, but the structural strength of the honeycomb structure is reduced

Engineering Contradiction:
Improvecontact areaVSAvoidstructural strength
Core Design Contradiction:
Area of stationary objectVSStrength

Solution Approach 1:

The convex-concave curved shape of the partition walls inherently provides structural reinforcement. The curved geometry distributes mechanical stresses more effectively compared to flat walls, allowing the partition walls to maintain adequate thickness for strength while still providing increased surface area for gas contact.

Inventive Principle:
Principle #14Spheroidality (Curvature)

Solution Approach 2:

The invention changes the geometric parameters of the partition walls by introducing curvature (convex-concave shape). This parameter change allows the same thickness to provide both sufficient structural strength and increased contact area, resolving the trade-off between strength and surface area.

Inventive Principle:
Principle #35Parameter changes

3Speed

If the cell density is increased to rapidly absorb heat and increase contact area, then the heat absorption speed is improved, but the complexity of the structure and manufacturing process increases

Engineering Contradiction:
Improveheat absorption speedVSAvoidstructure complexity
Core Design Contradiction:
SpeedVSDevice complexity

Solution Approach 1:

The convex-concave curved shape of the partition walls inherently increases the surface area within the same cell volume, effectively increasing the contact area without needing to increase cell density. This maintains faster heat absorption capability while avoiding the manufacturing complexity associated with higher cell densities.

Inventive Principle:
Principle #14Spheroidality (Curvature)

4Reliability

If the amount of catalyst is increased to improve purification performance, then the purification performance is improved, but the cost increases and the catalyst layer thickness increases, reducing the ratio of catalyst in contact with exhaust gas

Engineering Contradiction:
Improvepurification performanceVSAvoidcatalyst amount
Core Design Contradiction:
ReliabilityVSQuantity of substance

Solution Approach 1:

The convex-concave curved partition walls increase the contact area with exhaust gas, improving the efficiency of catalyst utilization. This allows for reduced catalyst loading while maintaining purification performance, as the increased surface area provides better gas-catalyst interaction without requiring additional catalyst material.

Inventive Principle:
Principle #14Spheroidality (Curvature)

Data Source

PatentEP2236190B1Honeycomb filter and manufacturing method of the same
Publication Date: 2013.06.19 NGK INSULATORS LTD
  • EP2236190B1 patent drawingFigure 1
  • EP2236190B1 patent drawingFigure 2
  • EP2236190B1 patent drawingFigure 3

AI summary

There is disclosed a honeycomb filter which can decrease a pressure loss while increasing a filter area, and a manufacturing method of the honeycomb filter. Above all, the decrease of the pressure loss while increasing the filter area and the improvement of a regeneration efficiency by the shortening of a regeneration time can be realized, and the structural strength of the whole honeycomb structure can be maintained. Moreover, the honeycomb filter can easily be formed, and a yield can be improved. A honeycomb filter 1 is constituted of a honeycomb structure comprising a large number of cells 3 (3a, 3b) which become through channels for an exhaust gas partitioned by partition walls 4 and having large and small sectional areas of the cells 3, provided with plugging portions 10 which alternately plug open ends 11 of the large number of cells 2, and comprises wave type cells 3 each having an only pair of facing surfaces 4b, 4b or regions thereof formed into a wavelike shape with an equal wavelength in a through channel direction of the cells 3.