DPF Inorganic Porous Layer with Concavo-Convex Surface

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Solution Overview

Problem

Conventional diesel particulate filters (DPFs) face issues with clogging due to accumulated particulate matter (PMs), leading to increased back pressure and reduced exhaust gas flow efficiency, as PMs accumulate both on the surface and inside the filter substrate, necessitating frequent regeneration methods like heating or fuel burning.

Innovation Solution

A DPF with an inorganic porous layer containing metal oxide or metal composite oxide, featuring a concavo-convex surface portion on the filter substrate's inflow side, which collects PMs and prevents them from entering the substrate's interior, thereby reducing back pressure and enhancing PM combustion efficiency through controlled gas flow and catalytic combustion using silver or silver compounds.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If PMs are collected in the surface of the dividing wall, then PM removal efficiency is improved, but back pressure increases and exhaust gas flow efficiency deteriorates

Engineering Contradiction:

ImprovePM removal efficiencyVSAvoidback pressure

Core Design Contradiction:

Object-affected harmful factorsVSStress or pressure

Solution Approach 1:

The dividing wall surface is segmented into multiple functional zones: a first region with a porous coating layer for PM collection, and a second region without coating for maintaining gas flow. This segmentation allows PM to be collected in specific areas while preserving uncoated regions that reduce flow resistance and back pressure.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different regions of the dividing wall are given different properties: the first region has a porous coating layer with specific pore characteristics optimized for PM capture, while the second region remains uncoated to maintain low flow resistance. This local differentiation resolves the contradiction between PM collection efficiency and gas flow efficiency.

Inventive Principle:

Principle #3Local quality

2Object-affected harmful factors

If the entire dividing wall surface is coated with porous material, then PM collection capability is improved, but device complexity and manufacturing difficulty increase

Engineering Contradiction:

ImprovePM collection capabilityVSAvoidmanufacturing difficulty

Core Design Contradiction:

Object-affected harmful factorsVSEase of manufacture

Solution Approach 1:

The coating is applied only to a portion (first region) of the dividing wall surface rather than the entire surface, simplifying the manufacturing process while maintaining effective PM collection. The uncoated second region reduces manufacturing complexity and material costs.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Instead of coating the entire dividing wall surface, the invention applies coating only to the extent necessary for effective PM collection (partial action). This reduces material usage, manufacturing complexity, and cost while achieving sufficient PM removal performance.

Inventive Principle:

Principle #16Partial or excessive action

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 concavo-convex surface design effectively collects and combusts PMs, preventing back pressure increases and improving combustion efficiency, while the catalytic component accelerates PM combustion, ensuring stable operation and reduced regeneration needs.

Implementation Method 1

an inorganic porous layer which contains a metal oxide or a metal composite oxide and is provided with a concavo-convex surface portion having a thickness of 50% to 95% of a thickness of the inorganic porous layer, the inorganic porous layer being formed on a partial or entire surface of the dividing wall

Methodology Applied

Scientific EffectPhysical filtration: Filter (physical)

Implementation Method 2

catalytic combustion using silver or silver compounds

Methodology Applied

Scientific EffectCatalytic combustion: Catalysis

Implementation Method 3

catalytic combustion using silver or silver compounds

Methodology Applied

Scientific EffectOxidation: Oxidation

Implementation Method 4

the exhaust gas flows through a gap caused by the concavo-convex surface portion

Methodology Applied

Scientific EffectGas flow through porous structure: Porosity

Data Source

PatentEP3001000B1Diesel particulate filter and exhaust gas purification device

Publication Date: 2017.12.13 MITSUI MINING & SMELTING CO LTD

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AI summary

Provided is a novel DPF which can prevent PM from accumulating on the surface and interior of a filter substrate, and can suppress an increase in back pressure caused by exhaust gas. The DPF has a configuration in which an inorganic porous layer, which includes a metal oxide or a metal composite oxide and is provided with surface irregularities having a thickness of at least 50% of the thickness of the inorganic porous layer, is formed on part or all of the surface of the dividing wall on the side where exhaust gas flows in.