Metallic-Foil Honeycomb Catalyst With Gradual Boundary Hole Density

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Solution Overview

Problem

Existing catalyst devices with laminated metallic foils in honeycomb cores experience varying strength at boundary regions due to through holes being densely arranged in a grid pattern, leading to reduced durability.

Innovation Solution

A catalyst device with a honeycomb core featuring a dense region, zero region, and boundary region where the through holes gradually decrease in area or number, maintaining the layout of through holes in the dense region while ensuring the boundary region's strength by configuring the boundary region only downstream of the dense region, and optionally providing multiple boundary regions upstream and downstream.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Area of stationary object

If through holes are densely arranged in a grid pattern in the honeycomb core, then the surface area is increased and thermal strain phenomena are reduced, but the strength of metallic foils varies at boundary regions between dense and zero regions, reducing durability

Engineering Contradiction:

Improvesurface area of honeycomb coreVSAvoidstrength of metallic foils at boundary region

Core Design Contradiction:

Area of stationary objectVSStrength

Solution Approach 1:

The patent applies local quality by creating different through hole density regions (dense region, boundary region, and zero region) with progressively varying hole densities. The boundary region specifically has a gradual transition in through hole density, which locally modifies the structural properties to maintain strength while preserving the overall benefits of high surface area from the dense region.

Inventive Principle:

Principle #3Local quality

2Reliability

If through holes are densely arranged in a grid pattern, then thermal strain phenomena are reduced, but the metallic foils are stretched by expansion of oxide film volume, further reducing durability

Engineering Contradiction:

Improveresistance to thermal strain phenomenaVSAvoiddurability of honeycomb core

Core Design Contradiction:

ReliabilityVSDuration of action of stationary object

Solution Approach 1:

The boundary region with gradually decreasing through hole density acts as a cushioning zone that prepares the metallic foils for the transition to the zero region. This gradual transition prevents sudden stress concentrations that would occur with abrupt boundaries, thereby cushioning against the stretching effects of oxide film expansion and improving overall durability.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

3Strength

If a boundary region with gradual through hole area reduction is introduced, then the strength of metallic foils at the boundary is maintained, but the device complexity increases

Engineering Contradiction:

Improvestrength of metallic foils at boundary regionVSAvoidcomplexity of through hole arrangement

Core Design Contradiction:

StrengthVSDevice complexity

Solution Approach 1:

The honeycomb core is segmented into distinct regions (dense region, boundary region, and zero region) with clearly defined through hole patterns. This segmentation allows each region to be optimized for its specific function while maintaining overall structural integrity, and the systematic approach to segmentation makes the manufacturing process manageable despite the increased complexity.

Inventive Principle:

Principle #1Segmentation

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

Enhances the durability of the honeycomb core by maintaining strength at boundary regions, improving exhaust gas purification efficiency and reducing the need for processing pins, while maintaining diffusion effects.

Implementation Method 1

reducing the thermal strain phenomena caused by internal temperature variations and the phenomena where the metallic foils are stretched by expansion of the volume of an oxide film

Methodology Applied

Scientific EffectThermal expansion: Thermal Expansion

Implementation Method 2

a catalyst device that purifies exhaust gas from an internal combustion engine has been known to include a honeycomb core that includes laminated metallic foils supporting a catalyst, such as platinum

Methodology Applied

Scientific EffectCatalysis: Catalysis

Data Source

PatentUS20250305434A1Catalyst device

Publication Date: 2025.10.02 HONDA MOTOR CO LTD

AI summary

A catalyst device (30) for purifying exhaust gas (G) by passing the exhaust gas (G) through a honeycomb core (31, 31a, 31b, 31c, 31d) includes: the honeycomb core (31, 31a, 31b, 31c, 31d) including a metallic foil (40) supporting a catalyst and wound. A portion of the metallic foil (40) has a plurality of through holes (H). The honeycomb core (31, 31a, 31b, 31c, 31d) has a dense region (A) where the through holes (H) are densely formed, a zero region (B) where no through hole (H) is formed, and a boundary region (C) between the dense region (A) and the zero region (B) in an axial direction in which the exhaust gas (G) flows. The boundary region (C) is configured such that a total area of the through holes (H) in the boundary region (C) decreases gradually from near the dense region (A) toward the zero region (B).