Exhaust Catalyst Coating via Gas-Flow Velocity Control
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Solution Overview
Problem
Existing methods for manufacturing exhaust gas-purifying catalysts struggle to accurately control the width of catalytic layers across different regions of the substrate, leading to variations in catalyst performance and efficiency.
Innovation Solution
A method and apparatus that utilize a reservoir attachment, pressure adjuster, and gas-flow control tool to control the flow of slurry into the substrate's holes, allowing for independent control of catalytic layer widths by adjusting pressure and gas flow velocities, enabling precise formation of catalytic layers with varying widths.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional coating methods are used to form catalytic layers on honeycomb substrates, then the coating process is simple and fast, but the width of catalytic layers cannot be accurately controlled across different regions
Solution Approach 1:
The coating apparatus divides the substrate into multiple regions (first region and second region) with different hole patterns. The first region has holes with larger diameters or different arrangements compared to the second region, allowing different slurry flow rates and catalytic layer widths in each region. This segmentation enables independent control of catalytic layer dimensions across different areas of the substrate.
Solution Approach 2:
The invention applies local quality by creating region-specific hole structures in the honeycomb substrate. Each region is designed with tailored hole diameters, hole densities, or hole arrangements to achieve desired local catalytic layer characteristics. This allows the catalytic layer width to be optimized for specific functional requirements in different regions while maintaining a single continuous substrate.
2Manufacturing precision
If slurry is supplied uniformly to all holes, then the coating process is simple, but the catalytic layer width varies uncontrollably across different cells
Solution Approach 1:
The invention introduces dynamic control of slurry flow by varying the hole characteristics across different regions. The hole diameters, shapes, or arrangements are dynamically adjusted from one region to another, creating different flow resistance and slurry distribution patterns. This dynamic structural variation enables precise control of catalytic layer width without complex external flow control mechanisms.
Solution Approach 2:
The invention changes physical parameters of the substrate holes (diameter, density, arrangement) to control slurry flow behavior. By modifying these geometric parameters across different regions, the slurry flow rate and pressure distribution are automatically adjusted, resulting in consistent catalytic layer width control throughout the substrate without requiring complex process adjustments.
3Productivity
If high flow velocity is used to remove excessive slurry, then the coating efficiency is high, but the catalytic layer thickness becomes non-uniform across upstream, midstream, and downstream sections
Solution Approach 1:
The invention introduces asymmetry in the hole patterns across different longitudinal sections of the substrate. The hole diameters, densities, or arrangements in the upstream region differ from those in the midstream and downstream regions. This asymmetric design creates different flow velocities and pressure gradients in each region, allowing excessive slurry to be removed efficiently while maintaining uniform catalytic layer thickness across the entire substrate length.
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 more accurate control of catalytic layer widths, reducing variations and improving the consistency and performance of exhaust gas-purifying catalysts, particularly in continuous production processes.
Implementation Method 1
reducing a pressure in a region adjacent to the second end face relative to a pressure in a region adjacent to the substrate with the slurry in the reservoir interposed therebetween to guide the slurry in the reservoir into the plurality of holes and generate flows of the slurry from the first end face toward the second end face
Implementation Method 2
the gas-flow control tool being configured to generate a distribution of linear velocities of gas flows when the gas-flow control tool faces the first end face and gas is passed therethrough toward the first end face
Data Source
AI summary
A method of manufacturing an exhaust gas-purifying catalyst comprising: moving a gas-flow control tool from a first position where the gas-flow control tool faces the first end face with the slurry in the reservoir interposed therebetween and is spaced apart from the slurry in the reservoir to a second position where the gas-flow control tool faces the first end face with a distance from the first end face shorter than that in the first position, in a period during which the slurry flows from the first end face's side toward the second end face's side, the gas-flow control tool being configured to generate a distribution of linear velocities of gas flows when the gas-flow control tool faces the first end face and gas is passed therethrough toward the first end face.