Exhaust Gas Purification Filter Pore Size Distribution
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional exhaust gas purification filters face challenges in maintaining trapping efficiency while minimizing pressure loss, especially in engines with reduced particulate matter amounts, as they are designed for higher particulate concentrations, leading to inadequate purification performance and increased pressure loss when particulate matter deposits are minimal.
Innovation Solution
An exhaust gas purification filter with a honeycomb structure and porous ceramic partition walls having a specific thickness, average pore size, and broadened pore size distribution, characterized by a proportion of larger pores, is developed to effectively trap particulate matter with reduced pressure loss, suitable for engines with lower particulate matter amounts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the pore size of partition walls is reduced to improve trapping efficiency, then trapping efficiency of particulate matter is improved, but pressure loss of the exhaust gas purification filter is increased
Solution Approach 1:
The patent applies parameter changes by precisely controlling the pore size distribution parameters of the partition walls. Specifically, it sets the average pore size between 3-6 μm and controls the standard deviation of logarithmic pore diameter distribution to 0.2-0.5, creating an optimized pore size distribution that balances trapping efficiency and pressure loss without simply reducing pore size.
Solution Approach 2:
The patent applies local quality by creating a specific pore size distribution pattern within the partition walls rather than using uniform pores. The controlled logarithmic normal distribution with specific standard deviation creates different pore size zones that work together to trap particles effectively while maintaining gas flow, addressing both trapping efficiency and pressure loss locally within the filter structure.
2Device complexity
If a conventional exhaust gas purification filter is used for engines with reduced particulate matter concentration, then the filter structure remains simple, but trapping efficiency cannot be maintained sufficiently
Solution Approach 1:
The patent addresses this contradiction by changing the pore size distribution parameters to match the reduced particulate matter concentration from engines with improved combustion. The specific control of average pore size (3-6 μm) and logarithmic standard deviation (0.2-0.5) optimizes the filter for lower particle concentrations while maintaining a relatively simple honeycomb structure, avoiding the need for complex multi-layer designs.
3Loss of energy
If the partition wall thickness is reduced to lower pressure loss, then pressure loss is decreased, but structural strength and trapping efficiency may be compromised
Solution Approach 1:
The patent applies parameter changes by optimizing the partition wall thickness to 0.05-0.18 mm, which is thinner than conventional filters to reduce pressure loss. This thickness parameter is carefully selected to maintain sufficient structural strength while maximizing gas flow efficiency and trapping performance for low-particulate exhaust gases.
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 achieves appropriate trapping efficiency and low pressure loss by specifying partition wall thickness between 0.05 mm and 0.18 mm, average pore size between 10 µm and 18 µm, and a pore size distribution with 5% to 40% of pores twice the average size, ensuring effective particulate matter removal and reduced pressure loss in engines with small particulate matter amounts.
Implementation Method 1
particulate matter in the exhaust gas is trapped by the partition walls when the exhaust gas passes through the partition walls
Data Source
Figure 1
Figure 2
AI summary
An exhaust gas purification filter 100 includes: a honeycomb structure 10 having porous ceramic partition walls 12 separating and forming a plurality of cells 11 functioning as exhaust gas passages and extending from one end portion 15a to the other end portion 15b, and plugging portions 13 disposed in one side open end portions of predetermined cells 11a and in the other side open end portions of the other cells 11b. The partition walls 12 have a thickness of 0.05 mm or more and 0.18 mm or less and an average pore size of 10 µm or more and 18 µm or less and the proportion of the volume of the pores having a size of twice the average pore size or more in the entire pore volume in a pore size distribution of the partition walls 12 measured by mercury porosimetry is 5% or more and 40% or less.