Exhaust Gas Purification Filter Partition Surface Roughness
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Solution Overview
Problem
Exhaust gas purification filters for gasoline engines face increased pressure drop due to the accumulation of ash components, which reduces gas permeability and requires effective mechanisms to manage ash component detachment and transport.
Innovation Solution
The exhaust gas purification filter features a partition with a specific surface roughness configuration, characterized by a total void volume and material volume within a certain range (1.8 μm3/μm2 or less), facilitating the detachment and transport of ash components through increased shearing force, thereby reducing pressure drop.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the partition surface is smooth, then gas permeability is maintained, but ash components accumulate and increase pressure drop
Solution Approach 1:
The partition surface is designed with non-uniform roughness characteristics - featuring peaks and valleys at specific scales (Arithmetic average roughness Ra: 0.5-2.0 μm, Maximum height roughness Rz: 2.0-4.0 μm). This local variation in surface topology creates zones with different ash accumulation and detachment behaviors, allowing the surface to simultaneously maintain gas permeability through permeable regions while promoting ash detachment through high-shear-force regions.
2Object-generated harmful factors
If the partition surface has high roughness, then ash components detach easily, but gas permeability decreases
Solution Approach 1:
The invention optimizes specific surface roughness parameters within defined ranges: Arithmetic average roughness Ra of 0.5-2.0 μm and Maximum height roughness Rz of 2.0-4.0 μm. These parameter ranges are carefully selected to balance two opposing effects - sufficient roughness to generate shear force for ash detachment, but not so much roughness as to block gas flow paths and reduce permeability.
3Strength
If the partition material volume is increased, then structural strength is improved, but void volume decreases reducing gas flow capacity
Solution Approach 1:
The invention defines an optimal total volume parameter (Vvv + Vmp) of 1.8 μm³/μm² or less, which represents a quantitative balance between solid material volume (providing strength) and void volume (providing gas flow capacity). By controlling the partition surface morphology to meet this volume constraint, the design achieves simultaneous optimization of mechanical strength and gas flow performance.
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
This configuration effectively maintains gas permeability by converting wall ash components into bottom ash components, reducing pressure drop increases and ensuring efficient filtration performance over long-term use.
Implementation Method 1
facilitating the detachment and transport of ash components through increased shearing force
Implementation Method 2
reducing pressure drop increases and ensuring efficient filtration performance
Data Source
AI summary
An exhaust gas purification filter includes a plurality of cells extending in a filter axial direction, a porous partition separating and defining the plurality of cells, and a sealing section sealing the plurality of cells alternately at both filter ends. In the exhaust gas purification filter, the partition has a void volume of a reduced dale, Vvv, and a material volume of a reduced peak, Vmp, as volume parameters determined in noncontact surface roughness measurement on a surface of the partition, with their total value being 1.8 μm3/μm2 or less.