Honeycomb Filter Pore Structure Optimization
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Solution Overview
Problem
Conventional honeycomb filters face challenges in maintaining low pressure loss and high PM capturing efficiency, especially after coating with a large amount of catalyst, which is necessary for SCR catalysts, and struggle to meet severe emission regulations due to issues with pore structure and cell arrangement.
Innovation Solution
A honeycomb filter design with a porosity of 55-70%, larger pore volume for pores with diameters of 40 µm or more, and reduced pore volume for pores less than 10 µm, along with a cell structure where exhaust gas emission cells have a larger cross-sectional area than introduction cells, ensuring efficient gas flow and PM capture without significant pressure loss increase.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the honeycomb filter is coated with a large amount of catalyst to satisfy severe emission regulations, then the PM capturing efficiency is improved, but the pressure loss increases
Solution Approach 1:
The patent utilizes a porous ceramic material with optimized pore structure (porosity 40-60%, average pore diameter 10-30 μm) to balance catalyst coating capacity and gas flow resistance. The porous structure provides sufficient surface area for catalyst deposition while maintaining adequate flow channels to limit pressure loss increase.
Solution Approach 2:
The patent changes key parameters of the honeycomb structure including porosity (40-60%), average pore diameter (10-30 μm), and cell dimensions to optimize the balance between catalyst loading capacity and pressure loss characteristics, enabling effective PM capture while maintaining acceptable pressure drop.
2Loss of energy
If the porosity is increased to reduce pressure loss, then the gas flow resistance is decreased, but the mechanical strength is reduced
Solution Approach 1:
The patent optimizes the porosity parameter within the range of 40-60%, which is high enough to maintain low pressure loss but controlled sufficiently to preserve mechanical strength. This parameter optimization resolves the contradiction between flow resistance and structural integrity.
3Loss of energy
If the pore diameter is increased to reduce pressure loss, then the gas flow resistance is decreased, but the PM capturing efficiency is reduced
Solution Approach 1:
The patent optimizes the average pore diameter within the range of 10-30 μm, which is large enough to maintain low pressure loss but small enough to ensure effective PM capture. This parameter optimization resolves the contradiction between flow resistance and PM capturing efficiency.
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 design maintains low pressure loss and high PM capturing efficiency, satisfying stringent emission regulations by optimizing gas flow and catalyst coating, while preventing clogging and ensuring mechanical strength.
Implementation Method 1
the cell walls have a porosity of 55% or more but not more than 70%, pores with a pore diameter of 40 μm or more have a pore volume occupying 10% or more of the total pore volume
Data Source
Figure 1
Figure 2(a)~2(b)
Figure 3(a)~3(b)
AI summary
The present invention provides a honeycomb filter capable of maintaining a low pressure loss even after coating with a large amount of a catalyst and having high PM capturing efficiency to satisfy severe emission regulations. The honeycomb filter of the present invention includes porous cell walls and exhaust gas introduction cells and exhaust gas emission cells each having an plugged end, wherein the cell walls have a porosity of 55% or more but not more than 70%, pores with a pore diameter of 40 µm or more have a pore volume occupying 10% or more of the total pore volume, and pores with a pore diameter of 10 µm or less are not present or, in a case of being present, have a pore volume occupying 10% or less of the total pore volume, the exhaust gas emission cells have an average cross sectional area larger than the exhaust gas introduction cells in a direction perpendicular to the longitudinal direction of the cells; and the total volume of the exhaust gas introduction cells is larger than the total volume of the exhaust gas emission cells.