Catalyst Converter with Graded Cell Density Substrate
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Solution Overview
Problem
Existing catalyst converters with uniform cell density struggle to achieve efficient exhaust gas purification due to uneven flow rate distribution, leading to insufficient catalyst usage and potential hydrogen sulfide production.
Innovation Solution
A catalyst converter with a substrate having varying cell densities in its center, intermediate, and peripheral areas, along with corresponding noble metal catalyst layers of different lengths, optimizing gas flow and contact areas for enhanced purification performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the cell density is made uniform throughout the substrate, then the manufacturing process is simple, but the flow rate distribution becomes uneven causing insufficient catalyst usage
Solution Approach 1:
The substrate is divided into three distinct areas (center, intermediate, peripheral) with progressively decreasing cell densities. This local differentiation matches the flow rate distribution pattern, ensuring that regions with higher flow rates have lower cell densities to prevent catalyst saturation, while regions with lower flow rates have higher cell densities to maximize catalyst utilization.
2Productivity
If the cell density is increased in the center area to match flow rate distribution, then catalyst usage efficiency improves, but the flow rate distribution difference between center and peripheral areas increases
Solution Approach 1:
The substrate is divided into three distinct areas (center, intermediate, peripheral) with progressively decreasing cell densities. This local differentiation matches the flow rate distribution pattern, ensuring that regions with higher flow rates have lower cell densities to prevent catalyst saturation, while regions with lower flow rates have higher cell densities to maximize catalyst utilization.
3Productivity
If the amount of noble metal catalyst is increased in the center area, then exhaust gas purification performance improves, but hydrogen sulfide production increases causing bad smell
Solution Approach 1:
The substrate is divided into three distinct areas (center, intermediate, peripheral) with progressively decreasing cell densities. This local differentiation matches the flow rate distribution pattern, ensuring that regions with higher flow rates have lower cell densities to prevent catalyst saturation, while regions with lower flow rates have higher cell densities to maximize catalyst utilization.
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 design effectively reduces flow rate distribution differences and increases catalyst layer contact areas, resulting in superior exhaust gas purification performance and reduced NOx emissions.
Implementation Method 1
a catalyst layer that is formed of a noble metal catalyst such as palladium or platinum is formed in a cell wall of a substrate having a number of cells. When the exhaust gas passes through the catalyst converter having the thus-configured substrate, CO is converted to CO2, NOx is converted to N2 and O2, and VOC is burned to produce CO2 and H2O.
Data Source
AI summary
A catalyst converter includes: a substrate (1) having a cell structure formed of a center area (1A) having the highest cell density, a peripheral area (1C) having the lowest cell density, and an intermediate area (1B) having the cell density between that of the center area and that of the peripheral area; a first catalyst layer formed in the center area (1A); a second catalyst layer formed in the intermediate area (1B); and a third catalyst layer formed in the peripheral area (1C). A length in a longitudinal direction of the second catalyst layer is longer than that of the first catalyst layer. A length in the longitudinal direction of the third catalyst layer is longer than that of the second catalyst layer. A ratio of the length in the longitudinal direction of the first catalyst layer to the length of the substrate is 65% or more.