Catalyst Layer Protrusions for Exhaust Gas Diffusion
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Solution Overview
Problem
Current catalysts for vehicle exhaust pipes, such as three-way and NOx storage-reduction catalysts, face challenges in achieving high purification efficiency for exhaust gases, particularly in lean-burn engine operations where NOx levels are higher.
Innovation Solution
A method involving the deposition of a catalyst slurry containing a catalyst metal on a support, followed by the deposition of water-absorbing polymer particles, expansion, drying, and firing, which creates a catalyst layer with projections and depressions that enhance gas diffusion and purification efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a smooth catalyst layer is formed on the support, then the manufacturing process is simple, but the gas diffusion and purification efficiency are insufficient
Solution Approach 1:
The invention applies curvature by forming protrusions and recesses on the catalyst layer surface instead of maintaining a smooth flat surface. The protrusions create turbulent flow patterns that enhance gas diffusion and contact between exhaust gas and catalyst, thereby improving purification efficiency while maintaining manufacturing simplicity through a straightforward slurry deposition process
Solution Approach 2:
The invention transitions from a two-dimensional smooth surface to a three-dimensional textured surface with protrusions and recesses. This dimensional change creates additional surface area and flow paths that enhance gas diffusion and catalytic activity, resolving the contradiction between manufacturing simplicity and purification efficiency
2Device complexity
If the catalyst layer has a flat surface, then the manufacturing process is straightforward, but turbulence and diffusion of exhaust gas are reduced
Solution Approach 1:
The invention introduces surface curvature through protrusions with specific radius ratios (R1/R2 between 0.5-2.0) that generate turbulent flow. This curvature design enhances gas diffusion without requiring complex manufacturing processes, as the protrusions are formed simply by controlling the slurry deposition and drying process
Solution Approach 2:
The invention applies local quality by creating specific protrusion patterns in different regions of the catalyst layer. The protrusions are strategically positioned to maximize turbulence generation in high-flow areas while maintaining catalytic activity, thereby improving gas diffusion efficiency without overall structural complexity
3Ease of manufacture
If conventional catalyst manufacturing methods are used, then the production process is simple, but uncontacted exhaust gas remains after purification
Solution Approach 1:
The protrusions with optimized curvature ratios create enhanced turbulent flow patterns that reduce dead zones and uncontacted exhaust gas. This simple geometric modification to the catalyst surface significantly improves purification completeness while maintaining manufacturing simplicity through conventional slurry deposition methods
Solution Approach 2:
The protrusion structure creates natural flow instability and turbulence that acts as a form of mechanical disturbance to the exhaust gas flow. This enhances mixing and contact between gas and catalyst surfaces, reducing uncontacted gas without requiring external vibration sources or complex manufacturing
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 method results in improved exhaust gas purification efficiency by creating a catalyst layer with a surface profile that facilitates turbulence and diffusion, reducing uncontacted exhaust gas and enhancing the removal of hydrocarbons, carbon monoxide, and nitrogen oxides.
Implementation Method 1
depositing particles of a water-absorbing polymer on a surface of the catalyst slurry, expanding the particles to a predetermined size with the water present in the catalyst slurry
Data Source
AI summary
A method for manufacturing a catalyst includes depositing a catalyst slurry containing at least a catalyst metal and water on a support, depositing particles of a water-absorbing polymer on a surface of the catalyst slurry, expanding the particles to a predetermined size with the water present in the catalyst slurry, and firing the support having the catalyst slurry and the particles deposited on the catalyst slurry.