Plugged Honeycomb Structure With Pass-Through Holes

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Solution Overview

Problem

The existing plugged honeycomb structures used in exhaust gas purifying devices face challenges with high pressure loss and frequent particulate removal treatments due to particulate deposition, which affects fuel efficiency and increases the residual ash amount.

Innovation Solution

The implementation of a plugged honeycomb structure with pass-through hole portions at partition wall intersections, optimizing the diameter ratio of these holes and their arrangement to enhance fluid flow and geometric surface area, reducing pressure loss and improving purification efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If plugging portions are formed to cells of both end faces in accordance with a predetermined arrangement standard, then particulate trapping efficiency is improved, but pressure loss increases significantly

Engineering Contradiction:

Improveparticulate trapping efficiencyVSAvoidpressure loss

Core Design Contradiction:

ReliabilityVSLoss of energy

Solution Approach 1:

The partition wall intersection portions are segmented into two types: those with pass-through holes and those without. This segmentation allows the structure to provide both particulate trapping surfaces and low-resistance flow paths, resolving the contradiction between trapping efficiency and pressure loss.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different regions of the partition wall intersection portions have different properties: some regions contain pass-through holes for low-resistance flow, while other regions maintain solid walls for particulate trapping. This local differentiation allows simultaneous optimization of both functions.

Inventive Principle:

Principle #3Local quality

2Loss of energy

If pass-through hole portions are formed in partition wall intersection portions, then pressure loss is decreased, but geometric surface area for particulate trapping is reduced

Engineering Contradiction:

Improvepressure lossVSAvoidgeometric surface area

Core Design Contradiction:

Loss of energyVSArea of stationary object

Solution Approach 1:

The partition wall intersection portions are divided into multiple units, with only some containing pass-through holes. This segmentation ensures that enough solid surface area remains for effective particulate trapping while providing sufficient low-resistance paths to reduce pressure loss.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The diameter ratio of pass-through holes to plugging portions is optimized within a specific range (0.05 to 0.74). This parameter optimization balances the competing requirements of reducing pressure loss through larger holes while maintaining sufficient trapping surface area.

Inventive Principle:

Principle #35Parameter changes

3Speed

If the diameter ratio of pass-through holes to plugging portions is increased, then fluid flow is improved and pressure loss is reduced, but particulate trapping efficiency may be compromised

Engineering Contradiction:

Improvefluid flowVSAvoidparticulate trapping efficiency

Core Design Contradiction:

SpeedVSReliability

Solution Approach 1:

The diameter ratio is optimized within a specific range (0.05 to 0.74) to balance fluid flow improvement and particulate trapping efficiency. This parameter optimization ensures that holes are large enough to reduce resistance but small enough to maintain effective trapping surfaces.

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

This design decreases initial and soot-related pressure loss, maintains high particulate trapping efficiency, and minimizes the frequency of particulate removal treatments by optimizing the open frontal area and geometric surface area, thus improving fuel efficiency and purification performance.

Implementation Method 1

pass-through hole portions which interconnect a pair of cells facing each other... to enable pass-through of a fluid

Methodology Applied

Scientific EffectFluid flow through porous structure: Permeation

Implementation Method 2

the exhaust gas passes through the porous partition walls, the partition walls therefore function as a filtering material, and particulates included in the exhaust gas are trapped in the partition walls and on the surfaces of the partition walls

Methodology Applied

Scientific EffectPhysical filtration: Filter (physical)

Implementation Method 3

plugging portions are formed to cells of the one end face... and the plugging portions are similarly formed to the residual cells of the other end face

Methodology Applied

Scientific EffectFlow direction control through geometric constraint: Geometry

Data Source

PatentUS10695708B2Plugged honeycomb structure

Publication Date: 2020.06.30 NGK INSULATORS LTD

AI summary

A plugged honeycomb structure includes a honeycomb structure body, and a plurality of plugging portions, the honeycomb structure body further includes pass-through hole portions each of which is formed in at least a part of a partition wall intersection portion in which the partition walls intersect in one end face and each of which interconnects a pair of cells facing each other at a position corresponding to the partition wall intersection portion to enable pass-through of a fluid, and a value obtained by dividing a diameter of a first virtual inscribed circle inscribed at a position of a minimum hole width of the pass-through hole portion by a diameter of a second virtual inscribed circle inscribed at a position of a minimum plugging width between the plugging portions facing each other is in a range of 0.05 to 0.74.