Honeycomb Filter Coating Layout for High Filtration and Low Pressure Drop
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Solution Overview
Problem
Existing emissions treatment articles face challenges in achieving high filtration efficiency and catalytic conversion efficiency while minimizing pressure drop penalties, particularly in gasoline particulate filters used with gasoline direct injection engines.
Innovation Solution
A filtration article comprising a plugged honeycomb filter body with inorganic deposits on the walls and a catalytic material in the pores, where the inorganic deposits are spaced away from the catalytic material, allowing for minimal overlap and penetration, achieved through a process of coating the catalytic material, depositing a filler material, and burning it off to create voids for the inorganic deposits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If inorganic deposits and catalytic material are combined in the same region of the filter body, then manufacturing process is simplified, but filtration efficiency and catalytic conversion efficiency cannot both be optimized
Solution Approach 1:
The filter body is segmented into distinct functional zones: the first region contains only inorganic deposits for filtration, while the second region contains only catalytic material for conversion. This spatial segmentation allows each material to perform its specific function optimally without interference, resolving the contradiction between manufacturing simplicity and functional efficiency.
Solution Approach 2:
Different regions of the filter body are assigned different material compositions tailored to their specific functions. The first region has high inorganic deposit concentration for filtration, while the second region has high catalytic material concentration for conversion. This local differentiation optimizes both filtration efficiency and catalytic conversion efficiency simultaneously.
2Reliability
If inorganic deposits penetrate deep into the porous ceramic walls, then filtration efficiency increases, but pressure drop penalty increases
Solution Approach 1:
The inorganic deposits are concentrated in the first region with controlled penetration depth into the porous ceramic walls. This localized deposition strategy ensures sufficient filtration efficiency while preventing excessive pressure drop that would result from deep penetration throughout the entire wall structure.
3Ease of manufacture
If catalytic material is placed in contact with inorganic deposits, then manufacturing is easier, but catalytic conversion efficiency decreases due to overlap and penetration
Solution Approach 1:
The filter body is divided into two distinct regions: the first region contains inorganic deposits while the second region contains catalytic material. This segmentation prevents overlap and penetration between the two materials, maintaining catalytic conversion efficiency while simplifying the manufacturing process through sequential deposition.
Solution Approach 2:
A spacer structure acts as an intermediary between the inorganic deposits and catalytic material, preventing direct contact and penetration while maintaining manufacturing feasibility. The spacer ensures proper spatial separation without complicating the overall manufacturing process.
4Reliability
If wall thickness is increased to accommodate more catalytic material, then catalytic conversion efficiency increases, but pressure drop penalty increases
Solution Approach 1:
The catalytic material is concentrated in the second region with optimized wall thickness, rather than uniformly distributed throughout. This localized concentration achieves high catalytic conversion efficiency while minimizing the overall pressure drop that would result from increased wall thickness across the entire filter body.
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 achieves high filtration efficiency exceeding 90% and maintains low pressure drop penalties by separating inorganic deposits and catalytic material, enhancing both filtration and catalytic conversion efficiency.
Implementation Method 1
inorganic deposits disposed on surfaces of the walls which define the inlet channels of the plugged honeycomb filter body
Implementation Method 2
a catalytic material disposed inside the walls of the plugged honeycomb filter body
Implementation Method 3
exhaust gas to be filtered enters inlet cells and passes through the cell walls to exit the filter via outlet channels, with the particulates being trapped on or within the inlet cell walls
Data Source
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Figure 5~6
AI summary
A method for making a filtration article comprising coating a catalytic material within porous ceramic walls of a honeycomb filter body, thereafter depositing a filler material within the body, and exposing the body to a surface treatment to deposit inorganic deposits within the body on one or more portions of the walls, and burning off the filler material. A filtration article comprises inorganic deposits disposed on walls defining inlet channels; and a catalytic material in pores of walls. At least a portion of the inorganic deposits comprise bridging inorganic deposits which at least partially extend over the pores that extend to the surface of the walls, and such bridging inorganic deposits are spaced away from the catalytic material which is disposed within the walls. Soot treatment is used to space away the bridging inorganic particles from the catalytic material and/or substantially separate the inorganic particles from the catalytic material.