Multi-Thickness Honeycomb Structure for Buckling-Resistant Canning
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Solution Overview
Problem
Thin-walled honeycomb bodies used in catalytic converters face challenges with isostatic strength due to buckling and deformation under canning pressures, leading to potential fracture and reduced performance in fast light-off and emissions control.
Innovation Solution
The development of thin-walled honeycomb bodies with buckling-resistant configurations, featuring intersecting porous walls with specific thickness ratios and cell densities, and the use of extrusion dies with precise slot thicknesses to produce honeycomb structures that enhance isostatic strength and cell density.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If wall thickness is reduced to increase cell density and surface area, then fast light-off and catalyst application surface area are improved, but isostatic strength decreases and buckling deformation occurs under canning pressures
Solution Approach 1:
The patent applies local quality by varying wall thickness within the honeycomb structure. Specifically, walls are configured with different thicknesses (e.g., 0.003 inch and 0.005 inch) in different locations to provide both high cell density for catalyst surface area and sufficient thickness in critical areas for isostatic strength and buckling resistance during canning.
Solution Approach 2:
The patent segments the honeycomb structure into repeating cell structures with specific configurations (e.g., 2x2, 3x3, 4x4 arrangements). This segmentation allows optimization of local wall thickness patterns that balance surface area requirements with structural integrity under canning pressures.
2Productivity
If cell density is increased to reduce startup emissions, then catalyst surface area is improved, but wall thickness must be reduced which compromises structural integrity
Solution Approach 1:
The patent uses local quality by implementing varied wall thicknesses within the honeycomb body to achieve high cell density (e.g., 900-1200 cpsi) for fast light-off performance while maintaining sufficient wall thickness in critical locations to prevent structural failure and ensure reliability during installation and operation.
Solution Approach 2:
The patent addresses the density-strength tradeoff by moving from a single wall thickness parameter to a multi-dimensional wall thickness distribution, where different wall segments have different thicknesses optimized for their specific functional requirements.
3Area of stationary object
If thin walls are used to achieve higher cell density, then emissions control surface area is improved, but buckling and deformation under pressure increase
Solution Approach 1:
The patent applies local quality by strategically varying wall thicknesses to provide maximum surface area for emissions control while reinforcing specific wall locations to resist buckling and deformation under canning pressures and operational stresses.
Solution Approach 2:
The patent creates a composite-like structure within the monolithic honeycomb body by combining walls of different thicknesses (e.g., 0.003 inch and 0.005 inch) to achieve both high surface area and structural stability, effectively creating a functionally graded structure.
4Area of stationary object
If wall thickness is reduced to increase cell density, then catalyst support surface area is improved, but manufacturing precision requirements increase due to thinner walls
Solution Approach 1:
The patent segments the extrusion die design into multiple slot thicknesses (e.g., first slot thickness and second slot thickness) corresponding to different wall thicknesses in the honeycomb body. This segmentation of the manufacturing process allows precise control over each wall thickness region, managing manufacturing precision requirements through structured die design.
Solution Approach 2:
The patent changes the extrusion die parameters by incorporating slots with different thicknesses to produce walls with varying thicknesses. This parameter variation in the manufacturing process enables the creation of optimized honeycomb structures that balance surface area with manufacturability.
Data Source
AI summary
A thin-walled honeycomb body (100) having a plurality of repeating cell structures (110) formed of intersecting porous thick walls (112V, 112H) and thin walls (114V, 114H). Each repeating cell structure (110) is bounded on its periphery by the thick walls (112V, 122H) of a first transverse thickness (Tk) and the thin walls (114V, 114H) have a second transverse thickness (Tt) that subdivides each repeating cell structure (110) into between 7 and 36 individual cells (108). In the thin-walled honeycomb body (100), the first transverse thickness (Tk) of the thick walls (112V, 112H) is less than or equal to 0.127 mm (0.005 inch) and the second transverse thickness (Tt) of the thin walls (114V, 114H) is less than or equal to 0.0635 mm (0.0025 inch), and Tk>Tt. Honeycomb extrusion dies and methods of manufacturing the thin-walled honeycomb body (100) having thick walls (112V, 112H) and thin walls (114V, 114H) are provided.