Honeycomb Filter Pore Distribution for Low Pressure Loss
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Solution Overview
Problem
Conventional honeycomb filters face challenges in achieving high filtration efficiency while minimizing pressure loss, as reducing average pore diameter increases pressure loss and increasing porosity compromises structural integrity.
Innovation Solution
A honeycomb filter with a specific pore diameter distribution (D10, D50, D90) and porosity range, determined by structural analysis, using a Granulometry method, to optimize trapping performance and reduce pressure loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the average pore diameter of the partition wall is reduced to improve filtration efficiency, then trapping performance is improved, but pressure loss increases
Solution Approach 1:
The invention applies local quality by creating a non-uniform pore diameter distribution within the partition wall. Specifically, it ensures that pores with cumulative volume of 10% or more have a diameter of 5 μm or more, while maintaining an average pore diameter of 10 μm or less. This local variation in pore size allows different regions of the partition wall to serve different functions: larger pores maintain pressure loss while smaller pores ensure trapping performance.
2Stress or pressure
If the porosity of the partition wall is increased to suppress pressure loss, then pressure loss is reduced, but the strength of the honeycomb filter decreases
Solution Approach 1:
The invention applies parameter changes by precisely controlling the pore diameter distribution parameters (D10, D50, D90) and porosity within specific ranges. It sets the average pore diameter to 10 μm or less, ensures D10 ≥ 5 μm, and controls porosity to 40-70%. These parameter optimizations allow the partition wall to maintain both low pressure loss and high strength by finding the optimal balance point in the pore structure parameters.
3Reliability
If the average pore diameter is reduced to improve filtration efficiency, then trapping performance is improved, but the identification accuracy of the honeycomb filter deteriorates due to measurement limitations
Solution Approach 1:
The invention replaces the conventional mercury press-in method with image observation methods (such as SEM or TEM) to measure pore diameter. This substitution eliminates the measurement errors caused by the mercury press-in method's inability to accurately measure pores with enlarged diameters. By using image observation, the invention can accurately characterize the pore diameter distribution and confirm that D10 ≥ 5 μm, ensuring both trapping performance and measurement accuracy.
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 trapping performance with reduced pressure loss by accurately managing small and large pores through precise pore diameter distribution and porosity, enhancing filtration efficiency and mechanical strength.
Implementation Method 1
the porous partition wall serves as a filter for trapping the particulate matter in exhaust gas
Data Source
AI summary
A honeycomb filter comprising a pillar-shaped honeycomb structure body having a porous partition wall and a plugging portion, wherein, in a pore diameter distribution of the partition wall, in the case where the pore diameter (μm) whose cumulative pore volume is 10% of the total pore volume is denoted by D10, the pore diameter (μm) whose cumulative pore volume is 50% of the total pore volume is denoted by D50, and the pore diameter (μm) whose cumulative pore volume is 90% of the total pore volume is denoted by D90, all of the following equations (1) to (6) are satisfied.3.9 μm<D10≤6.2 μm (1)10.5 μm<D50<16.6 μm (2)28.3 μm<D90<38.7 μm (3)(log D90−log D10)/log D50<0.80 (4)log D90/log D50<1.36 (5)log D50/log D10<1.56 (6).