Micro-structured Substrate for Catalytic Convertor Surface Area
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Solution Overview
Problem
Conventional catalytic converters have limitations in geometric surface area, which affects the pressure drop and flow dynamics of exhaust gases, necessitating narrower passages to increase surface area, but this approach has a maximum geometric surface area of around 5000 m2/m3 for automotive applications.
Innovation Solution
The use of hollow fibre membranes with micro-structured substrates, such as sheets or rods, fabricated using a combined phase inversion and sintering technique, providing a high geometric surface area without the need for narrow passages, allowing for a catalytically active coating and improved mechanical, thermal, and chemical properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If the number of passages through the monolith substrate is increased to increase geometric surface area, then the geometric surface area is improved, but the passage width must be reduced which increases pressure drop and deteriorates flow dynamics
Solution Approach 1:
The invention transitions from a conventional 2D planar substrate surface to a 3D hierarchical micro-structured surface with protrusions and recesses. This dimensional change allows the fluid to flow over a significantly increased surface area without reducing passage width, as the additional surface area is created vertically rather than by adding more passages laterally.
Solution Approach 2:
The substrate incorporates a micro-structured surface with controlled porosity features including protrusions and recesses. These porous-like structures increase the effective surface area available for catalytic reaction while maintaining open flow paths that prevent excessive pressure drop, combining the benefits of high surface area with good flow dynamics.
2Area of stationary object
If the passage width is reduced to increase geometric surface area, then the geometric surface area is improved, but the flow dynamics deteriorate
Solution Approach 1:
Instead of increasing surface area by reducing passage dimensions in the flow plane, the invention creates additional surface area in the vertical dimension through micro-structured protrusions and recesses. This allows maintained passage width for good flow dynamics while achieving high geometric surface area through vertical surface complexity.
Solution Approach 2:
The micro-structured surface incorporates curved and rounded features rather than sharp edges, with protrusions and recesses having smooth transitions. This curvature improves flow dynamics by reducing turbulence and dead zones while maintaining high surface area, making the substrate easier to operate with better flow characteristics.
3Area of stationary object
If a micro-structured substrate with high geometric surface area is used, then the surface area for catalytic reaction is improved, but the manufacturing complexity increases
Solution Approach 1:
The invention controls the micro-structured surface by adjusting manufacturing parameters such as particle size distribution, suspension concentration, and drying conditions. By changing these parameters, the geometric surface area can be tuned to achieve the desired level without requiring complex multi-step fabrication processes, thus managing device complexity while maintaining high surface area.
Solution Approach 2:
The substrate structure is formed through a self-organizing process where particles naturally arrange into a micro-structured configuration during drying and sintering. This self-service mechanism creates the complex high-surface-area structure without requiring external intervention or complex manufacturing equipment, reducing device complexity despite the sophisticated final structure.
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 enables a larger surface area for catalytic converters, potentially reducing the amount of catalyst required for high performance and improving flow dynamics, while being cost-effective and adaptable to various substrate geometries.
Implementation Method 1
a combined phase inversion and sintering technique
Implementation Method 2
a combined phase inversion and sintering technique
Data Source
AI summary
A catalytic convertor comprising a substrate body (100) arranged within the catalytic convertor such that a principal flow of fluid through the catalytic convertor flows along a surface (101) of the substrate body, wherein said surface (101) has a plurality of openings (210) to micro-channels that extend away from said surface (101); and at least a portion of the surface (101) of the substrate body (100) comprises a catalytically active material, wherein the substrate body (100) is in the form of: a pellet; a sheet; solid elongate bodies; solid rods; a solid body having a plurality of bores; a non-tubular elongate body; a non-hollow body; a sheet curved in the form or a spiral; or a combination thereof.