Honeycomb Core Curvature Reduces Pressure Loss
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Solution Overview
Problem
The offset structure in catalytic converters increases pressure loss and reduces purification performance due to unnecessary turbulent flow and catalyst distribution inefficiencies, leading to inadequate exhaust gas purification.
Innovation Solution
By setting the radius of curvature of bent parts in the honeycomb core's corrugated foil within specific ranges (0.02 mm to 2.0 mm), the generation of non-purifying turbulent flow and unnecessary catalyst deposition are minimized, optimizing flow channels and catalyst distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If an offset structure with angular connection parts is used to generate turbulent flow, then purification performance is enhanced, but pressure loss increases due to non-purifying turbulent flow in connection parts
Solution Approach 1:
The patent applies different geometric characteristics to different parts of the corrugated foil: the connection parts have a radius of curvature of 0.02-2.0mm to minimize non-purifying turbulence, while the wave parts maintain angular connections to generate purifying turbulence. This local differentiation optimizes both pressure loss and purification performance in respective regions.
Solution Approach 2:
The patent introduces curvature (radius of curvature of 0.02-2.0mm) at the connection parts between wave parts and flat foils to replace the conventional angular connection. This curvature modification reduces flow separation and non-purifying turbulent flow, thereby decreasing pressure loss while maintaining the offset structure's purification capability.
2Productivity
If an offset structure is used to increase turbulent flow, then purification performance is enhanced, but catalyst distribution becomes inefficient in non-purifying regions
Solution Approach 1:
The patent creates distinct flow characteristics in different regions: connection parts with curved surfaces (radius of curvature 0.02-2.0mm) that minimize non-purifying turbulence and catalyst waste, and wave parts with angular connections that maintain purifying turbulence. This ensures catalyst is effectively utilized only in regions contributing to purification.
3Loss of energy
If the radius of curvature of bent parts is decreased to reduce non-purifying turbulence, then pressure loss is reduced, but manufacturing precision becomes more difficult to control
Solution Approach 1:
The patent specifies an optimal range for the radius of curvature (0.02-2.0mm) at connection parts, balancing the reduction of non-purifying turbulence with manufacturability. This parameter optimization ensures sufficient pressure loss reduction while maintaining feasible manufacturing precision for mass production.
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 reduces pressure loss and enhances purification performance by ensuring that catalysts are effectively applied to regions contributing to exhaust gas purification, while maintaining or improving the converter's ability to convert pollutants.
Implementation Method 1
the flow of exhaust gas is changed from laminar flow to turbulent flow, and an action of stirring exhaust gas is caused
Implementation Method 2
a catalytic converter carrying a catalyst is used to purify a problematic gas component, which impairs the human body when it is emitted in the air, such as HC (hydrocarbon), CO (carbon monoxide), and NOx (nitrogen compound)
Implementation Method 3
Exhaust gas can be purified by allowing the exhaust gas to flow through the inside of the exhaust gas flow channels from an end surface on an inlet side toward an end surface on an outlet side of the honeycomb core
Data Source
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AI summary
[Problem] To suppress the generation of turbulent flow that does not contribute to the purification of exhaust gas to decrease the pressure loss, and to decrease the amount of the catalyst applied to the region that does not contribute to the purification of exhaust gas. [Solution] A honeycomb core for carrying a catalyst, comprising a flat metal foil and a corrugated metal foil, the flat metal foil and the corrugated metal foil being layered, wherein the corrugated foil is configured by repeating a concavo-convex shaped part including a first top surface that is in contact with one of the flat foils adjacent in a layering direction, a second top surface that is in contact with another flat foil adjacent in the layering direction and is disposed at a position where the second top surface avoids the first top surface as viewed in the layering direction, and an inclined leg surface that has one end connected to the first top surface through a first bent part and another end connected to the second top surface through a second bent part, and extends in a direction inclined with respect to the first top surface and the second top surface, and has an offset part having different wave phases between front and rear in an axial direction of the honeycomb core,the first bent part and the second bent part each have a R shape,a radius of curvature R1 of an inner edge of the first bent part and a radius of curvature R2 of an inner edge of the second bent part satisfy the following conditional expressions (1) and (2), respectively, and a separation distance h in the layering direction between the first top surface and the second top surface and a separation distance S between a pair of the inclined leg surfaces connected to the first top surface through the first bent parts satisfy the following conditional expression (3) :0.02 (mm) ≤ R1 ≤ 2.0 (mm) (1),0.02 (mm) ≤ R2 ≤ 2.0 (mm) (2), and 1.5 ≤ S/h ≤ 10 (3).