Porous Ceramic Honeycomb Filter Pore Size Control
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Solution Overview
Problem
Diesel particulate filters face challenges in minimizing backpressure while maintaining filtration efficiency and thermal shock resistance, primarily due to the clogging of small pores by wash coatings, which increases pressure drop and hinders engine performance.
Innovation Solution
A porous ceramic honeycomb filter with an oxide-based material, such as cordierite or aluminum titanate, is designed with a controlled pore size distribution where d1 ≥ 7.0 µm, minimizing small pores and achieving a narrow pore size distribution to reduce wash-coated pressure drop and improve filtration efficiency and thermal shock resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If wash coating is applied to the filter surface to improve filtration efficiency, then catalytic activity increases, but small pores become clogged and back pressure increases
Solution Approach 1:
The invention changes the pore size parameter by ensuring d1 ≥ 7.0 μm, which prevents wash coating from clogging small pores while maintaining filtration efficiency. This parameter change resolves the contradiction by allowing catalytic coating without excessive back pressure increase.
2Reliability
If pore size is reduced to improve filtration efficiency, then soot capture increases, but pressure drop increases due to clogged small pores
Solution Approach 1:
The invention optimizes the pore size parameter by setting d1 ≥ 7.0 μm, which balances filtration efficiency with acceptable pressure drop. This parameter change ensures that pores are small enough for good filtration but large enough to avoid excessive clogging and pressure loss.
3Reliability
If SiC material is used to improve filtration performance, then catalytic activity increases, but cost and weight increase due to multi-component design requirements
Solution Approach 1:
The invention changes the material parameter by using cordierite with d1 ≥ 7.0 μm, which provides adequate filtration performance without requiring expensive multi-component SiC designs. This parameter change simplifies the device structure and reduces cost while maintaining functionality.
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 effectively minimizes wash-coated pressure increase, maintains low backpressure, and enhances filtration efficiency and thermal shock resistance, achieving a significant reduction in pressure drop while maintaining excellent filtration and heat capacity.
Implementation Method 1
a porous ceramic honeycomb filter article which exhibits a very small amount of small pores... the porous ceramic honeycomb filter article includes both a very small amount of small pores and also a narrow pore size distribution
Data Source
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AI summary
A porous ceramic honeycomb filter manufactured from an oxide-based ceramic material having a pore size distribution with d1 > 7.0 microns. Preferably, the oxide-based material is cordierite or aluminum titanate. Alternatively, the filter contains a cordierite-containing ceramic body with a narrow pore size distribution with db <1.00, wherein db = (d90 - d10) / d50. Also disclosed is a batch mixture, method and honeycomb green body made from mixture of inorganic source materials selected from the group of magnesia sources, alumina sources, and silica sources, and a pore former having a narrow particle size distribution with dps < 0.90, wherein dps = {(dp90-dp10)/dp50}. The pore former is preferably selected from a group consisting of canna starch, sago palm starch, green mung bean starch, and single-mode potato starch.