Annular Exhaust Purification Substrate with Segmented Heating
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Solution Overview
Problem
Existing exhaust gas purification members in vehicles face challenges in achieving optimal performance when the engine is cold, due to insufficient temperature of exhaust gases, leading to nonhomogeneous heating and potential substrate damage from differential expansion.
Innovation Solution
The design features intersecting walls extending from the outer to the inner cylindrical walls, arranged on isopotential circles, with specific electrode configurations and materials like silicon carbide, to ensure homogeneous electrical heating and reduce the time to reach optimal performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If a strong electrical current is circulated in the substrate to heat the catalytic material rapidly, then the purification member achieves optimal performance faster, but the heating becomes nonhomogeneous causing performance degradation and substrate breaking
Solution Approach 1:
The substrate is divided into multiple segments with intersecting walls that extend from the outer cylindrical wall to the inner cylindrical wall. These walls are covered with catalytic composition and create multiple heating zones. By segmenting the heating path, the electrical current is distributed more uniformly across the substrate cross-section, preventing localized overheating and differential expansion while maintaining rapid heating overall.
Solution Approach 2:
The intersecting walls are strategically positioned at isopotential circles, creating zones with different electrical potential characteristics. This local variation in electrical properties ensures that each zone receives appropriate heating intensity, achieving homogeneous temperature distribution across the entire substrate while maintaining rapid overall heating.
2Speed
If the substrate is made from electrically conductive material for rapid heating, then the catalytic material reaches activation temperature faster, but the electrical power distribution within the substrate is poor
Solution Approach 1:
The substrate incorporates intersecting walls that segment the electrical current path. These walls extend radially from the outer to inner cylindrical walls and are positioned at isopotential circles, creating multiple parallel current paths. This segmentation ensures uniform power distribution across the substrate cross-section while maintaining high heating speed through the electrically conductive material.
3Loss of time
If electrical heating is applied to the purification member, then the catalytic material reaches optimal temperature faster, but differential expansion causes substrate breaking
Solution Approach 1:
The intersecting walls divide the substrate into multiple segments that can expand more uniformly during heating. By creating this segmented structure with walls positioned at isopotential circles, the thermal expansion is distributed evenly across all segments, preventing the differential expansion that would otherwise cause substrate breaking while maintaining rapid heating.
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 solution enables rapid and uniform temperature increase of the purification member, reducing the time to achieve optimal performance and preventing substrate damage, while allowing for efficient heating of exhaust gases and downstream purification members.
Implementation Method 1
circulate a strong electrical current in this substrate when starting the engine, or even before starting the engine, so as to cause rapid heating of the substrate, and in this manner, of the catalytic material deposited thereupon
Data Source
AI summary
An exhaust gas purification member comprises an annular substrate centered on a central axis, a peripheral electrode alongside and against an outer cylindrical face of the substrate, and a central electrode alongside and against an inner cylindrical face of the substrate. The substrate is made up of an electrically conductive material and includes a plurality of intersecting walls defining longitudinal cells therebetween and that each emerge in an upstream face and in a downstream face of the substrate. These intersecting walls are covered with a catalytic composition and each wall extends from an outer cylindrical wall of the substrate, defining the outer cylindrical face, to the inner cylindrical wall of the substrate, defining the inner cylindrical face.