Exhaust Gas Purification Filter Surface Roughness Optimization
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Solution Overview
Problem
Existing exhaust gas purification filters face challenges in achieving high NOx conversion efficiency while maintaining PM collection efficiency and reducing pressure drop, as increasing catalyst amounts can block pores and decrease PM collection efficiency.
Innovation Solution
The exhaust gas purification filter features a porous partition with specific surface roughness parameters, including a total volume value between 1.3 μm3/μm2 and 1.7 μm3/μm2, mean pore size of 12 μm to 20 μm, and porosity of 50% to 75%, which allows for effective NOx conversion without increasing catalyst amounts, maintaining PM collection efficiency and reducing pressure drop.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If catalyst amount is increased to improve NOx conversion efficiency, then NOx conversion efficiency is improved, but pore blockage increases and PM collection efficiency decreases
Solution Approach 1:
The invention changes the surface roughness parameters of the partition (controlling void volume Vvv and material volume Vmp within specific ranges) to optimize the balance between NOx conversion efficiency and PM collection efficiency, eliminating the need to increase catalyst amount
2Productivity
If catalyst amount is increased to improve NOx conversion efficiency, then NOx conversion efficiency is improved, but pressure drop increases
Solution Approach 1:
The invention optimizes the partition surface roughness parameters (void volume Vvv and material volume Vmp within specific ranges) to enhance NOx conversion efficiency without requiring additional catalyst, thereby preventing pressure drop increase
3Productivity
If partition surface roughness is increased to improve NOx conversion efficiency, then NOx conversion efficiency is improved, but PM collection efficiency may decrease
Solution Approach 1:
The invention precisely controls the surface roughness parameters (void volume Vvv and material volume Vmp within specific ranges) to achieve the optimal balance point where NOx conversion efficiency is maximized while PM collection efficiency is maintained
Solution Approach 2:
The invention utilizes the porous structure of the partition with controlled surface roughness (void volume Vvv and material volume Vmp within specific ranges) to facilitate both NOx conversion and PM collection functions simultaneously
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
This configuration achieves a higher initial NOx conversion rate while maintaining initial PM collection efficiency and reducing pressure drop, preventing catalyst blockage and ensuring effective PM filtration.
Implementation Method 1
To purify exhaust gas by trapping PM in the exhaust gas, an exhaust gas purification filter is installed in the exhaust passage of an internal combustion engine
Implementation Method 2
increasing catalyst amounts can block pores and decrease PM collection efficiency
Data Source
AI summary
An exhaust gas purification filter includes a plurality of cells extending in a filter axial direction, a porous partition separating and defining the plurality of cells, and a sealing section sealing the plurality of cells alternately at both filter ends. The partition has a void volume of a reduced dale, Vvv, and a material volume of a reduced peak, Vmp, as volume parameters determined in noncontact surface roughness measurement on a surface of the partition, with their total value being more than 1.3 μm3/μm2 and 1.7 μm3/μm2 or less. The partition has a mean pore size of 12 μm or more and 20 μm or less. The partition also has a porosity of 50% or more and 75% or less.