Catalyst Support with Tapered Width for Uniform Temperature
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Solution Overview
Problem
Catalytic converters face non-uniform temperature distribution due to varying current density and heat generation, leading to inefficiencies in catalyst support heating and purifying exhaust gases.
Innovation Solution
A catalyst support with gradually decreasing width portions at electrode contact regions and wider non-contact regions, where the maximum width portion is limited to 93% of the center line length, ensures balanced heat generation and dissipation, promoting uniform temperature distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a circular cross-section catalyst support is used with opposing electrodes, then the structure is simple and easy to manufacture, but the current density becomes non-uniform causing non-uniform heat generation
Solution Approach 1:
The catalyst support employs different cross-sectional shapes at different locations: circular at the electrode contact portions and quadrilateral at the central portion. This local variation in geometry allows the support to maintain simplicity where electrodes contact while achieving uniform current density distribution in the central region, thereby resolving the contradiction between ease of manufacture and temperature uniformity.
2Temperature
If a quadrilateral cross-section catalyst support is used, then the current density becomes uniform, but heat dissipation from electrodes becomes excessive causing large temperature differences
Solution Approach 1:
The catalyst support employs different cross-sectional shapes at different locations: circular at the electrode contact portions and quadrilateral at the central portion. This local variation in geometry allows the support to maintain simplicity where electrodes contact while achieving uniform current density distribution in the central region, thereby resolving the contradiction between ease of manufacture and temperature uniformity.
3Temperature
If the width of the catalyst support is increased to reduce current density, then heat generation becomes more uniform, but the mountability on cylindrical exhaust pipes deteriorates
Solution Approach 1:
The catalyst support employs different cross-sectional shapes at different locations: circular at the electrode contact portions and quadrilateral at the central portion. This local variation in geometry allows the support to maintain simplicity where electrodes contact while achieving uniform current density distribution in the central region, thereby resolving the contradiction between ease of manufacture and temperature uniformity.
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 reduces temperature non-uniformity and achieves a more uniform heat generation across the catalyst support, enhancing the purifying effect and mountability on cylindrical exhaust pipes.
Implementation Method 1
when electricity is supplied to the catalyst support by a pair of electrodes 16A, 16B that are disposed so as to contact the catalyst support 14, the catalyst support 14 is heated and the temperature thereof is raised
Data Source
Figure 1A
Figure 1B
Figure 2
AI summary
To provide a catalytic converter that reduces non-uniformity of temperature of a catalyst support and that can approach a uniform temperature distribution, and a structural body for supporting a catalyst that structures this catalytic converter. At a catalyst support (14), gradually decreasing width portions (14D), at which a width W thereof gradually decreases toward electrode centers (16C), are formed at regions where electrodes (16A), (16B) are contactingly disposed, as seen in a cross-section orthogonal to a direction in which exhaust flows. The width W is shorter than a length L1 of a center line CL at a given position. Heat generation and heat dissipation of the catalyst support (14) are balanced overall.