Catalyst Support Hole Pattern for Uniform Strength
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Solution Overview
Problem
Catalyst supports in exhaust systems experience nonuniform strength due to uneven distribution of holes, leading to potential buckling under thermal stress from exhaust gas discharge.
Innovation Solution
A catalyst device with a catalyst support formed by stacked and rolled thinned metal flat and corrugated plates, featuring holes aligned in specific patterns to ensure uniform strength, where holes on adjacent lines overlap, and hole sizes vary to enhance durability and exhaust gas cleaning efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If holes are distributed nonuniformly in the catalyst support, then the catalyst support can be manufactured with simpler hole patterns, but the catalyst support experiences buckling under thermal stress due to nonuniform strength
Solution Approach 1:
The patent applies local quality by making the holes nonuniform in size rather than uniform. Specifically, holes in upstream second lines (closer to exhaust gas inlet) are made larger than holes in downstream second lines. This local variation in hole quality compensates for the nonuniform thermal stress distribution, preventing buckling while maintaining manufacturability.
2Productivity
If holes are made larger to improve exhaust gas cleaning efficiency, then the catalyst support strength is reduced, but if holes are made smaller to maintain strength, then the exhaust gas cleaning efficiency decreases
Solution Approach 1:
The patent resolves this contradiction by applying local quality through spatially varying hole sizes. Larger holes are positioned in upstream regions where exhaust gas flow rate and thermal stress are higher, improving cleaning efficiency where needed. Smaller holes are positioned in downstream regions where strength requirements are more critical. This local differentiation allows both high productivity and adequate strength to be achieved simultaneously.
Data Source
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AI summary
Provided is a catalyst device that can equalize the strength of a carrier in the direction of the flow of exhaust gas. According to the present invention, a flat plate (52) and a corrugated plate (54) have a plurality of holes (64). When the flat plate (52) and the corrugated plate (54) are in a flat state before being made into a carrier (42), the plurality of holes (64) form: a plurality of first rows (66) that run along a first direction (D1) that is parallel to the axial direction of the carrier (42); and a plurality of second rows (68) that run along a second direction (D2) that is orthogonal to the first direction (D1). As seen from the second direction (D2), the holes (64) in one second row (68) and the holes (64) in the other second row (68) of adjacent second rows (68) have portions (64p) that overlap each other.