Honeycomb Filter Open Cell Design Reduces Pressure Loss

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Solution Overview

Problem

Gasoline engines, while offering better fuel economy than diesel engines, generate exhaust gases with lower particulate matter (PM) concentrations, requiring a filter with low pressure loss and potentially reduced PM capture efficiency, posing a challenge in maintaining fuel economy and effective PM filtration.

Innovation Solution

A honeycomb filter design where a majority of cells are sealed at one end and a portion are open at both ends, with the number of open cells ranging from 0.2% to 1.1% of the total cells, to minimize pressure loss without compromising PM capture efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If all cells are sealed at one end to maximize PM capture efficiency, then PM capture efficiency is improved, but pressure loss increases

Engineering Contradiction:
ImprovePM capture efficiencyVSAvoidpressure loss
Core Design Contradiction:
ReliabilityVSLoss of energy

Solution Approach 1:

The patent applies local quality by creating different cell types within the same filter: sealed cells (where both ends are closed) for high PM capture efficiency, and open cells (where both ends are open) for low pressure loss. This allows different regions of the filter to serve different functions - sealed cells capture PM while open cells provide low-resistance flow paths, resolving the contradiction between capture efficiency and pressure loss.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent changes the structural parameter of cells from uniformly sealed to a mixed configuration with sealed and open cells. By controlling the proportion of open cells (5-50% of total cells), the patent optimizes the balance between PM capture efficiency and pressure loss, achieving both high filtration performance and low energy loss simultaneously.

Inventive Principle:
Principle #35Parameter changes

2Loss of energy

If open cells are increased to reduce pressure loss, then pressure loss is reduced, but PM capture efficiency decreases

Engineering Contradiction:
Improvepressure lossVSAvoidPM capture efficiency
Core Design Contradiction:
Loss of energyVSReliability

Solution Approach 1:

The patent maintains local quality differentiation by ensuring that sealed cells are distributed throughout the filter structure to provide PM capture functionality, while open cells provide flow paths. The specific arrangement and proportion (5-50% open cells) are optimized to maintain high PM capture efficiency while achieving low pressure loss, preventing the deterioration of either property.

Inventive Principle:
Principle #3Local quality

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 significantly reduces pressure loss while maintaining high PM capture efficiency, addressing the need for efficient filtration in gasoline engines without deteriorating fuel economy.

Implementation Method 1

PMs contained in the exhaust gas are captured by the cell wall when passing through the filter

Methodology Applied
Scientific EffectFiltration: Filter (physical)

Data Source

PatentEP2329874B1Honeycomb filter and exhaust gas purifying apparatus
Publication Date: 2013.06.12 IBIDEN CO LTD
  • EP2329874B1 patent drawingFigure 1
  • EP2329874B1 patent drawingFigure 2
  • EP2329874B1 patent drawingFigure 3(a)~3(b)

AI summary

An object of the present invention is to provide a honeycomb filter capable of significantly decreasing a pressure loss without any appreciable reduction in capture efficiency of PM, and the honeycomb filter of the present invention is a honeycomb filter, including a plurality of cells longitudinally disposed in parallel with one another with a cell wall interposed therebetween, wherein a majority of the plurality of cells are sealed cells sealed at either one end, a part of the plurality of cells is an open cell open at both ends, and the number of the open cell is 0.1 to 4.9% of the number of the plurality of cells.