Honeycomb Filter Partition Walls for Stable Pressure Loss
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Solution Overview
Problem
Honeycomb filters used in exhaust systems experience variations in pressure loss and filtration efficiency due to non-uniform pore conditions, which are not adequately captured by conventional evaluation methods, leading to instability in performance.
Innovation Solution
A honeycomb filter design with specific parameters for partition wall thickness, porosity, average pore diameter, and communication pore shape, characterized by a ratio of minimum to maximum pore width (X/Y) within a defined range, to stabilize pressure loss and filtration efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional evaluation methods (porosity and average pore diameter) are used to assess the porous body, then the evaluation process is simple, but the trapping performance and pressure loss performance show large variations and stable performance cannot be obtained
Solution Approach 1:
The patent changes the evaluation parameters from conventional simple metrics (porosity, average pore diameter) to a more comprehensive set including pore shape regularity index and communication pore characteristics. This parameter transformation enables reliable performance prediction while maintaining evaluation feasibility through standardized measurement procedures.
Solution Approach 2:
The patent replaces conventional mechanical/physical evaluation methods with image processing and computational analysis techniques. By capturing pore structure images and calculating regularity indices through digital processing, the system achieves more reliable performance assessment without excessive complexity.
2Manufacturing precision
If the pore shape is non-uniform, then the manufacturing process is simpler, but the trapping performance and pressure loss performance cannot be sufficiently grasped and stable performance cannot be obtained
Solution Approach 1:
The patent introduces the pore shape regularity index as a controllable parameter during manufacturing. By setting target values for this index and measuring actual values, the manufacturing process can be adjusted to achieve uniform pore shapes, improving both trapping performance and pressure loss characteristics.
Solution Approach 2:
The patent implements a feedback mechanism where the pore shape regularity index is measured and used to adjust manufacturing parameters. This closed-loop control ensures that pore uniformity is maintained within acceptable ranges, achieving stable performance without excessive manufacturing complexity.
3Loss of energy
If the partition wall thickness is reduced to lower pressure loss, then the pressure loss decreases, but the structural strength and filtration efficiency may be compromised
Solution Approach 1:
The patent optimizes the partition wall thickness parameter within a specific range (152-305 μm) to achieve the best balance between pressure loss reduction and structural strength maintenance. This parameter optimization ensures adequate strength while minimizing energy loss.
Solution Approach 2:
The patent specifies using porous ceramic materials with particular properties (porosity 35-70%, controlled pore structure) for the partition wall. These composite material characteristics enable the partition wall to maintain sufficient strength at reduced thickness, achieving both low pressure loss and high structural integrity.
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 design effectively suppresses performance variations in pressure loss and filtration efficiency, ensuring stable performance in gasoline and diesel particulate filters.
Implementation Method 1
a porous partition wall disposed so as to surround a plurality of cells which serve as fluid through channels
Data Source
AI summary
A honeycomb filter includes a pillar-shaped honeycomb structure having a porous partition wall disposed to surround a plurality of cells anda plugging portion, whereina thickness of the partition wall is 152 to 305μm,a porosity of the partition wall is 35% to 70%,an average pore diameter of the partition wall is 7μm to 24μm,a porous body constituting the partition wall has a communication pore which opens to the surface of the partition wall and communicates with a pore inside the partition wall, and the communication pore has a narrow part where the diameter is partially narrowed, andin a virtual single pore obtained by virtually dividing the communication pore at the narrow part, an average of a ratio (X/Y) of a minimum width X (μm) to a maximum width Y (μm) passing through the center of gravity of the virtual single pore is 0.51 to 1.00.