Ceramic Honeycomb Filter Pore Architecture for Diesel PM Capture
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Solution Overview
Problem
Ceramic honeycomb filters for diesel engines struggle to efficiently capture nano-sized particulate matter (PM) while maintaining low pressure loss, as existing technologies either compromise on PM-capturing efficiency or suffer from high pressure loss due to the contradictory nature of these filter characteristics.
Innovation Solution
A ceramic honeycomb filter with a porosity of 45-75%, a median pore diameter ratio of 35<(A−B)/B×100≦70, and a maximum pore diameter of 100 μm or less, combined with a cordierite-based structure and specific particle size distributions for the starting materials, enhances PM-capturing efficiency while minimizing pressure loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the pore size is reduced to capture nano-sized PM, then PM-capturing efficiency is improved, but pressure loss increases
Solution Approach 1:
The patent employs a porous ceramic honeycomb structure with specifically controlled pore characteristics. The cell walls contain pores with a median diameter of 0.03-0.6 μm and porosity of 30-70%, creating a porous material that captures nano-sized PM while maintaining adequate flow paths to limit pressure loss.
Solution Approach 2:
The patent optimizes multiple parameters simultaneously: pore median diameter (0.03-0.6 μm), porosity (30-70%), and the ratio of pore volume to cell wall volume (0.05-2.0). By adjusting these parameters within specific ranges, the filter achieves both high PM-capturing efficiency for nano-sized particles and acceptable pressure loss characteristics.
2Loss of energy
If the porosity is increased to reduce pressure loss, then pressure loss is reduced, but PM-capturing efficiency decreases
Solution Approach 1:
The patent utilizes a porous ceramic structure where the pore distribution and size are carefully controlled. The porous cell walls with median pore diameter of 0.03-0.6 μm and porosity of 30-70% provide sufficient capture capability for nano-sized PM while maintaining low pressure loss through optimized pore architecture.
Solution Approach 2:
The patent employs a composite pore structure within the cell walls, combining pores of different sizes with a specific volume ratio (0.05-2.0). This composite approach allows smaller pores to capture nano-sized PM effectively while larger pores maintain flow capacity, resolving the contradiction between capture efficiency and pressure loss.
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 captures nano-sized PM with improved efficiency and maintains low pressure loss, ensuring the ceramic honeycomb filter's durability and performance in diesel engine exhaust applications.
Implementation Method 1
a ceramic honeycomb structure having a large number of flow paths partitioned by porous cell walls and plugs disposed in the flow paths alternately on an exhaust gas inlet or outlet side, to remove particulate matter from exhaust gas passing through the porous cell walls
Data Source
AI summary
A ceramic honeycomb filter including a ceramic honeycomb structure having large numbers of flow paths partitioned by porous cell walls, and plugs disposed in the flow paths alternately on the exhaust gas inlet or outlet side, to remove particulate matter from an exhaust gas passing through the porous cell walls; the porous cell walls having porosity of 45-75%, the median pore diameter A (μm) of the cell walls measured by mercury porosimetry, and the median pore diameter B (μm) of the cell walls measured by a bubble point method meeting the formula of 35<(A−B)/B×100≦70, and the maximum pore diameter of the cell walls measured by a bubble point method being 100 μm or less.