Catalyzed Particulate Filter with Porous Supporting Member
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Solution Overview
Problem
Catalyzed particulate filters face challenges in increasing catalyst loading while minimizing back pressure, which affects contact time and filter performance, as thick catalyst coatings can block pores and increase pressure, and increasing cell density reduces wall thickness, deteriorating filter performance.
Innovation Solution
Incorporating a catalyzed supporting member with a porous structure, such as ceramic or metal foams, inside the outflow channels to increase catalyst loading without raising back pressure, by coating the catalyst on the supporting member rather than the porous wall, thereby enhancing contact time and filter performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the catalyst is coated thickly on the porous wall, then the catalyst loading amount increases, but the micro pores are blocked and back pressure increases
Solution Approach 1:
The catalyst coating is divided into two separate locations: a thin layer on the porous wall and additional catalyst on supporting members positioned in the outflow channels. This segmentation allows the porous wall to maintain its filtering function with minimal catalyst coating, while the supporting members provide additional catalyst loading area without blocking the pores.
Solution Approach 2:
Supporting members are introduced as intermediary structures in the outflow channels. These members serve as additional surfaces for catalyst deposition, acting as a mediator between the need for high catalyst loading and the requirement to maintain low back pressure by keeping the porous wall pores open.
2Area of stationary object
If the cell density is increased to increase catalyst surface area, then the catalyst contact area increases, but the wall thickness is reduced and filter performance deteriorates
Solution Approach 1:
Instead of increasing cell density in the planar dimension, the invention extends the catalyst surface area into the third dimension by placing supporting members within the outflow channels. This allows increased catalyst contact area without reducing wall thickness or increasing cell density.
3Stress or pressure
If the catalyst is thinly coated to minimize back pressure, then the back pressure is reduced, but the catalyst reaction is not sufficiently generated
Solution Approach 1:
The invention combines two catalyst coating approaches: a thin catalyst layer on the porous wall for basic catalytic activity and additional catalyst coating on supporting members in the outflow channels. This merging provides sufficient total catalyst loading for effective reaction while maintaining thin wall coatings that do not block pores and keep back pressure low.
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 approach allows for increased catalyst loading and contact time with the fluid while maintaining wall thickness, thereby improving filter and catalyst performance without increasing back pressure.
Implementation Method 1
When the fluid passes through the porous wall, the particulate matter included in the fluid does not pass the porous wall, but is collected
Implementation Method 2
The catalytic converter is configured to purify a carbon monoxide (CO), a hydrocarbon (HC) and a nitrogen oxide (NOx) included in the exhaust gas
Data Source
AI summary
A catalyzed particulate filter includes at least one inflow channel including one end where a fluid inflows and another end that is blocked and extends in a length direction, at least one outflow channel including one end that is blocked and another end where the fluid outflows, and the other end extends in the length direction, at least one porous wall defining a boundary between the inflow channel and the outflow channel neighboring each other and extending in the length direction, and a catalyzed supporting member disposed on an inside of the outflow channel, wherein the supporting member includes a plurality of balls.