Porous Collection Layer Structure for Low-Pressure-Loss Filtration
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Solution Overview
Problem
Existing honeycomb filters face a tradeoff between pressure loss and collection efficiency, making it difficult to simultaneously reduce pressure loss while maintaining high collection efficiency for particulate matter in exhaust gases from engines.
Innovation Solution
A porous complex is developed with a base material and a collection layer that have air permeability, featuring a dense foam network structure, specific porosity and pore diameters, and a collection layer formed from alumina or silicon carbide, which is deposited using a dry deposition method to minimize penetration into the base material pores.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a collection layer with high surface roughness and thickness is provided to improve collection efficiency, then collection efficiency is improved, but pressure loss increases
Solution Approach 1:
The collection layer is designed as a porous sintered body with controlled porosity (75-95%) and mean pore diameter (0.3-1.5 μm), allowing exhaust gas to pass through while capturing particulate matter. The porous structure provides both collection efficiency and air permeability, resolving the contradiction between capturing particles and maintaining low pressure loss.
Solution Approach 2:
The invention optimizes specific parameters of the collection layer including porosity (75-95%), mean pore diameter (0.3-1.5 μm), and mean membrane thickness (20-45 μm). By precisely controlling these parameters, the collection layer achieves high collection efficiency while maintaining low pressure loss, directly addressing the tradeoff relationship.
2Reliability
If the collection layer penetrates into the base material pores to improve collection efficiency, then collection efficiency is improved, but air permeability decreases and pressure loss increases
Solution Approach 1:
The collection layer is designed to cover the inner surfaces of the base material cells without penetrating deeply into the base material pores. This local quality control ensures that the collection layer provides high collection efficiency on the surface while maintaining the air permeability of the base material structure underneath.
Solution Approach 2:
The porous complex is segmented into distinct functional layers: the base material providing air permeability and the collection layer providing particle capture. This segmentation allows each layer to optimize its specific function without compromising the other, resolving the contradiction between collection efficiency and air permeability.
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 porous complex achieves high collection efficiency with low pressure loss, effectively capturing particulate matter from engine exhausts while maintaining air permeability, thus balancing efficiency and pressure loss.
Implementation Method 1
a base material which is a porous sintered body having air permeability, and a collection layer which is a porous sintered body provided on the base material and having air permeability
Data Source
AI summary
A porous complex includes a base material that is a porous sintered body having air permeability, and a collection layer that is a sintered body provided on the base material and having air permeability, the collection layer exhibiting a dense foam network structure in a longitudinal section. The collection layer is formed by depositing and firing porous particles on the base material. This suppresses the penetration of the collection layer into pores of the base material and allows the porous complex to achieve high collection efficiency and low pressure loss.