Ceramic Honeycomb Filter Pore Structure for Low Pressure Loss
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Solution Overview
Problem
Conventional honeycomb filters face a trade-off between reducing pressure loss and maintaining thermal durability due to increased pore volume, leading to thermal stress and deterioration.
Innovation Solution
A honeycomb filter with a ceramic porous partition wall having a high ratio of small pores (10 μm or less) and an average pore diameter of 4 to 10 μm, along with a tortuosity factor of 1.31 or less, reduces gas streamline tortuosity and friction, effectively trapping particulate matter on the surface while suppressing pressure loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If pore volume of the porous partition wall is increased to reduce pressure loss, then pressure loss is reduced, but heat capacity is reduced and thermal stress increases, deteriorating thermal durability
Solution Approach 1:
The invention changes the pore size distribution parameters of the partition wall, specifically controlling the ratio of small pores (10 μm or less) to total pore volume to be 85-95% and the average pore diameter to be 4-10 μm. This parameter optimization allows the partition wall to maintain lower pressure loss while preserving sufficient heat capacity for thermal durability, resolving the contradiction between pressure loss reduction and thermal durability maintenance.
2Productivity
If pore volume is increased to improve exhaust gas flow, then pressure loss decreases, but temperature difference increases causing larger thermal stress
Solution Approach 1:
The invention optimizes pore size distribution parameters (small pore ratio of 85-95% and average pore diameter of 4-10 μm) to achieve a balance where exhaust gas flow is improved with reduced pressure loss, while the partition wall maintains sufficient heat capacity to minimize temperature differences and thermal stress, thus resolving the contradiction between productivity and stress resistance.
3Loss of energy
If small pores are increased to reduce pressure loss, then pressure loss is suppressed, but trapping efficiency of particulate matter may be affected
Solution Approach 1:
The invention precisely optimizes the pore size distribution parameters, setting the ratio of small pores (10 μm or less) to total pore volume at 85-95% and average pore diameter at 4-10 μm. This specific parameter range maintains low pressure loss while preserving adequate trapping efficiency for particulate matter, resolving the contradiction between pressure loss reduction and trapping 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 filter achieves excellent thermal durability and suppresses pressure loss by enhancing the trapping efficiency of particulate matter, maintaining mechanical strength and reducing catalyst penetration.
Implementation Method 1
the porous partition wall serves as a filter for trapping the particulate matter in exhaust gas
Implementation Method 2
a ratio of a volume of pores having a pore diameter of 10 μm or less with respect to a total pore volume of the partition wall measured by a mercury press-in method is 85 to 95%, and an average pore diameter of the partition wall measured by the mercury press-in method is 4 to 10 μm
Data Source
AI summary
A honeycomb filter includes a pillar-shaped honeycomb substrate having a porous partition wall disposed so as to surround a plurality of cells serving as a fluid through channel extending from a first end face to a second end face; and a plugging portion provided at an open end on the first end face side or the second end face side of each of the cells, wherein the partition wall constituting the honeycomb substrate is composed of a ceramic porous material, a ratio of a volume of pores having a pore diameter of 10 μm or less with respect to a total pore volume of the partition wall measured by a mercury press-in method is 85 to 95%, and an average pore diameter of the partition wall measured by the mercury press-in method is 4 to 10 μm.