Cordierite Honeycomb Filter Pore Structure Optimization
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Ceramic honeycomb filters for diesel engines face challenges in achieving both low pressure loss and high strength, particularly when used in industrial applications or large filters over 200 mm in diameter, as they often compromise on either strength due to mechanical vibration and shock.
Innovation Solution
A cordierite-based ceramic honeycomb filter with a balanced pore structure, including porosity of 45-58%, average pore size of 15-30 µm, and specific pore size distribution, combined with a production method using silica and pore-forming materials to optimize porosity and strength, ensuring low pressure loss and high mechanical resilience.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If porosity and average pore size of the ceramic honeycomb structure are increased to reduce pressure loss, then capturing efficiency is improved, but strength decreases making the filter unable to withstand mechanical vibration and shock
Solution Approach 1:
The invention changes the pore size distribution parameters by controlling the volume percentages of different pore size ranges. Specifically, it sets the volume of pores exceeding 50 μm at 10-25%, pores of 100 μm or more at 1-8%, and pores less than 10 μm at 3-10%, with a pore size distribution deviation σ of 0.6 or less. This parameter optimization achieves the balance between low pressure loss and high strength by preventing excessive large pores that weaken structure while maintaining enough large pores for low pressure loss.
Solution Approach 2:
The invention uses a composite pore structure within the cell walls that combines different pore size ranges in specific proportions. The cell walls contain a hierarchy of pores (small pores <10 μm, medium pores 10-50 μm, and large pores >50 μm) with controlled volume distributions, creating a composite porous material that simultaneously provides mechanical strength from the dense matrix and low pressure loss from the large pore channels.
2Loss of energy
If porosity is increased to achieve low pressure loss, then capturing time is extended, but strength becomes insufficient for industrial applications and large filters
Solution Approach 1:
The invention optimizes the pore size distribution parameters to achieve the right balance. By controlling the volume of pores exceeding 50 μm to be 10-25% (not too high to maintain strength, not too low to keep pressure loss low) and setting the pore size distribution deviation σ to 0.6 or less, the filter achieves both low pressure loss and sufficient strength for industrial applications and large filter sizes.
3Loss of energy
If average pore size is increased to reduce pressure loss, then capturing efficiency is improved, but the filter cannot withstand mechanical vibration and shock in industrial applications
Solution Approach 1:
The invention changes the pore size distribution by controlling the volume percentages of different pore size ranges and limiting the pore size distribution deviation σ to 0.6 or less. This prevents the formation of excessive large pores that would create weak points, while still maintaining enough large pores (10-25% volume exceeding 50 μm) to ensure low pressure loss and good capturing efficiency.
Solution Approach 2:
The cell walls are designed as a composite porous structure containing multiple pore size ranges with controlled distributions. The combination of small pores (<10 μm at 3-10% volume), medium pores (10-50 μm), and large pores (>50 μm at 10-25% volume) creates a hierarchical composite structure that provides both mechanical resilience against vibration and shock, and low flow resistance for efficient particle capture.
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 balances pressure loss and strength, enabling ceramic honeycomb filters to withstand mechanical vibration and shock, making them suitable for industrial applications and large filters without compromising on efficiency or durability.
Implementation Method 1
permitting an exhaust gas to pass through said porous cell walls to remove particulate matter from the exhaust gas
Data Source
Figure 1(a)~1(b)
Figure 2~3
Figure 4~5
AI summary
A cordierite-based ceramic honeycomb filter comprising a honeycomb structure having a large number of flow paths partitioned by porous cell walls, and plugs alternately formed in said flow paths on the exhaust-gas-inlet side or the exhaust-gas-outlet side for permitting an exhaust gas to pass through said porous cell walls to remove particulate matter from the exhaust gas, said porous cell walls having porosity of 45-58%, an average pore size of 15-30 µm, the volume of pores having pore sizes exceeding 50 µm being more than 10% and 25% or less of the total pore volume, the volume of pores having pore sizes of 100 µm or more being 1-8% of the total pore volume, the volume of pores having pore sizes of less than 10 µm being 3-10.% of the total pore volume, and said pores having a pore size distribution deviation σ [= log (D20) - log (D80)] of 0.6 or less, wherein D20 represents a pore size (µm) at a pore volume corresponding to 20% of the total pore volume, and D80 represents a pore size (µm) at a pore volume corresponding to 80% of the total pore volume, both in a curve representing the relation between the pore size and the cumulative pore volume, and D80 < D20.