Gasoline Particulate Filter Coating for Low Back Pressure
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Gasoline particulate filters face challenges in achieving high fresh filtration efficiency with low back pressure to meet stringent emission regulations like Euro 6 and China 6.
Innovation Solution
A particulate filter design with inorganic particles having a small BET pore volume of no more than 0.5 cm3/g applied on the porous walls of the substrate channels, enhancing filtration efficiency without significant back pressure increase.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a TWC catalytic material is coated onto or within a filter, then three-way conversion functionality is provided, but back pressure increases
Solution Approach 1:
The patent applies different coating densities to different regions of the filter. The inlet side has a lower coating density (higher porosity) to minimize back pressure, while the outlet side has a higher coating density (lower porosity) to provide sufficient three-way conversion functionality. This local differentiation resolves the contradiction between maintaining low back pressure and providing adequate catalytic function.
2Reliability
If synthetic ash is loaded on the inlet side, then particle filtration performance improves over lifetime, but fresh filtration efficiency is reduced
Solution Approach 1:
The patent applies a thin layer of synthetic ash on the outlet side before the filter is put into service. This preliminary action ensures that ash is already present to catalyze the conversion of gaseous pollutants during the entire operational life, including the critical fresh filtration phase, thereby improving both lifetime performance and initial efficiency.
Solution Approach 2:
The patent differentiates ash loading between inlet and outlet sides. The inlet side has minimal or no ash coating to maintain low back pressure and good fresh filtration efficiency, while the outlet side has sufficient ash loading to provide catalytic functionality throughout the filter's lifetime.
3Reliability
If the coating porosity is reduced to provide three-way conversion, then catalytic functionality is achieved, but back pressure increases
Solution Approach 1:
The patent implements spatially varying porosity in the coating layer. The inlet side maintains high porosity (lower coating density) to minimize flow resistance and back pressure, while the outlet side has reduced porosity (higher coating density) to ensure adequate three-way conversion functionality. This gradient structure resolves the contradiction between catalytic performance and pressure drop.
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 filter provides improved fresh filtration efficiency while maintaining low back pressure, addressing the need for higher performance in gasoline engine exhaust treatment.
Implementation Method 1
a particulate filter, which comprises a substrate, comprising a plurality of porous walls extending longitudinally to form a plurality of parallel channels extending from an inlet end to an outlet end
Implementation Method 2
a layer of inorganic particles loaded on surfaces of porous walls in the inlet channels and/or outlet channels, wherein the layer of inorganic particles comprises inorganic particles having a small BET pore volume of no more than 0.5 cm3/g
Data Source
AI summary
The present invention relates to a particulate filter, which comprises a substrate comprising a plurality of porous walls extending longitudinally to form a plurality of parallel channels extending from an inlet end to an outlet end, wherein a quantity of the channels are inlet channels that are open at the inlet end and closed at the outlet end, and a quantity of channels are outlet channels that are closed at the inlet end and open at the outlet end; and a layer of inorganic particles loaded on surfaces of porous walls in the inlet channels and/or outlet channels, wherein the layer of inorganic particles comprises inorganic particles having a small BET pore volume of no more than 0.5 cm3/g. The present invention also relates to a method for producing a particulate filter which includes applying inorganic particles or precursors thereof.