Catalyst-Carrying Filter with Segmented Pore Layers
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Solution Overview
Problem
Existing catalyst-carrying filters for internal combustion engines face challenges in efficiently trapping and oxidizing particulate matter, leading to reduced catalyst durability and frequent regeneration due to heat-generated deterioration, incomplete soot combustion, and decreased NOx purification efficiency.
Innovation Solution
A catalyst-carrying filter design with a gas purification catalyst layer on the inflow-side and a PM trapping layer on the outflow-side, featuring a PM removal catalyst layer with a larger oxidizing catalyst amount and smaller pore size, optimized for efficient particulate matter trapping and oxidation, reducing catalyst deterioration and improving regeneration efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a trapping layer with small average pore size is formed on the outflow-side layer to trap particulate matter, then particulate matter trapping efficiency is improved, but catalyst deterioration due to heat increases
Solution Approach 1:
The partition wall is divided into multiple layers: a large-pore-size layer on the inflow side and a small-pore-size trapping layer on the outflow side. This segmentation allows different regions to perform different functions - the large-pore layer handles gas flow and initial filtration, while the small-pore layer traps particulate matter, preventing catalyst deterioration.
Solution Approach 2:
Different pore sizes are assigned to different locations of the partition wall. The inflow-side layer has large pores to facilitate gas flow and reduce resistance, while the outflow-side layer has small pores specifically for trapping particulate matter. This local differentiation optimizes both trapping efficiency and catalyst protection.
2Reliability
If the average pore size decreases from the center toward each side of the partition wall, then particulate matter trapping is improved, but pressure loss increases
Solution Approach 1:
The partition wall is segmented into two distinct layers with different pore sizes. The large-pore inflow-side layer minimizes pressure loss by allowing easy gas flow, while the small-pore outflow-side layer provides effective particulate matter trapping. This segmentation resolves the contradiction between trapping efficiency and pressure loss.
3Productivity
If catalyst is supported on the surface of the trapping layer, then particulate matter oxidation is promoted, but catalyst deterioration due to rapid temperature increase occurs
Solution Approach 1:
The trapping layer is extracted as a distinct small-pore-size layer positioned on the outflow side, separate from the catalyst-supported inflow-side layer. This extraction allows the trapping layer to capture particulate matter before it reaches the catalyst, preventing rapid temperature increases that would deteriorate the catalyst while still enabling oxidation promotion.
4Productivity
If the pore size of one opening is made larger than the other opening, then particulate matter enters the partition wall easily, but particulate matter may flow out to the purified-gas-outflow-side cells
Solution Approach 1:
The partition wall is segmented into an inflow-side layer with large pores for easy particulate matter entry and an outflow-side layer with small pores for effective containment. This segmentation ensures that particulate matter can easily enter through the large pores while being trapped by the small pores, preventing it from flowing out to purified gas cells.
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 effectively purifies unburnt gases, traps particulate matter, and enhances catalyst durability, improving regeneration efficiency and maintaining purification performance by ensuring efficient contact between particulate matter and the oxidizing catalyst.
Implementation Method 1
The inflow-side layer of the partition wall is constituted as a gas purification catalyst layer which supports a gas purification catalyst promoting oxidation of unburnt gases
Implementation Method 2
The outflow-side layer of the partition wall is constituted as a PM trapping layer having a small average pore size so as to trap particulate matter
Implementation Method 3
The PM trapping layer is constituted as a PM removal catalyst layer which supports a PM removal catalyst promoting oxidation of particulate matter
Data Source
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AI summary
A catalyst-carrying filter is installed directly under an engine and has a partition walls. An inflow-side layer of the partition walls includes a gas purification catalyst layer, and a outflow-side layer of the partition walls includes a PM trapping layer that has a small average pore size and a PM removal catalyst layer that promotes oxidation of particulate matter contained in exhaust gas.