Exhaust Gas Purification Filter With Optimized Pore Structure
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, such as direct gasoline-injection and natural gas compression ignition engines, due to differences in required trapping efficiency and pore size distribution compared to conventional diesel engines.
Innovation Solution
An exhaust gas purification filter with a honeycomb structure featuring porous partition walls and a surface trapping layer, where the partition walls have a broadened pore size distribution, reduced thickness, and specific average pore size, combined with a surface trapping layer of controlled porosity and thickness, to effectively trap particulate matter while reducing pressure loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the pore size of partition walls is reduced to improve trapping efficiency, then trapping efficiency is improved, but pressure loss is increased
Solution Approach 1:
The partition walls utilize porous ceramic materials with specifically controlled pore size distributions (bimodal or multimodal distribution with peaks at different pore sizes) to achieve both high trapping efficiency for fine particulate matter and low pressure loss through optimized pore structure. The porous structure allows selective filtration based on pore size while maintaining gas flow permeability.
Solution Approach 2:
The invention changes the pore size distribution parameters of the partition walls from conventional narrow distributions to broadened bimodal or multimodal distributions. This parameter change enables the partition walls to trap particulate matter across a wider size range while maintaining adequate flow characteristics, thus achieving both high trapping efficiency and low pressure loss simultaneously.
2Loss of energy
If the partition wall thickness is reduced to decrease pressure loss, then pressure loss is reduced, but trapping efficiency deteriorates
Solution Approach 1:
The partition walls utilize porous ceramic materials with specifically controlled pore size distributions (bimodal or multimodal distribution with peaks at different pore sizes) to achieve both high trapping efficiency for fine particulate matter and low pressure loss through optimized pore structure. The porous structure allows selective filtration based on pore size while maintaining gas flow permeability.
Solution Approach 2:
The partition walls are constructed as composite porous ceramic structures combining materials with different pore size characteristics. This composite structure enables the thin partition walls to provide both adequate trapping performance and low flow resistance by integrating multiple pore size regimes within a single thin wall structure.
3Reliability
If a surface trapping layer is added to improve trapping efficiency, then trapping efficiency is improved, but device complexity increases
Solution Approach 1:
The surface trapping layer is merged with the partition wall structure to form an integrated composite component. The trapping layer and partition wall are combined into a single structural unit during manufacturing, eliminating the need for separate assembly steps and reducing overall device complexity while enhancing trapping performance.
Solution Approach 2:
The surface trapping layer is pre-formed on the partition wall surface during the manufacturing process before the filter element is assembled into the exhaust system. This preliminary formation of the trapping layer ensures optimal trapping efficiency from the start of operation and eliminates the need for separate installation steps.
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 solution enables efficient particulate matter removal with reduced pressure loss, suitable for engines with low particulate matter amounts, maintaining trapping efficiency while minimizing pressure loss, thus addressing the limitations of conventional filters.
Implementation Method 1
particulate matter in the exhaust gas is trapped by the partition walls when the exhaust gas passes through the partition walls
Implementation Method 2
a surface trapping layer disposed on the surface of each of the cells having open end portions on an exhaust gas inflow side
Data Source
Figure 1
Figure 2
Figure 3
AI summary
An exhaust gas purification filter 100 includes: a honeycomb structure 10 having porous ceramic partition walls 12, 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, and a surface trapping layer 14 having an average pore size of 0.1 µm or more and 5 µm or less, a porosity of 50% or more and 80% or less, and a thickness of 1 µm or more and 50 µm or less. 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, which is measured by mercury porosimetry, 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.