Nested Honeycomb Exhaust Gas Treating Device
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Solution Overview
Problem
Conventional exhaust gas treating devices face challenges in being compact, easily heated, and resistant to rapid cooling, particularly when dealing with high-temperature exhaust gases from gasoline engines, and they often suffer from increased pressure loss due to the use of ceramic catalyst carriers with mats, which affect their efficiency and durability.
Innovation Solution
The design incorporates a honeycomb structure with an inner and outer honeycomb body, where the outer body has thicker partition walls and a smaller cell density, and plugging portions are strategically arranged to enhance temperature management and reduce pressure loss, while being stored in a can member that facilitates efficient gas flow and heat exchange.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the filter volume is increased to reduce pressure loss, then pressure loss is reduced, but the device size increases
Solution Approach 1:
The patent employs a nested structure where the inner honeycomb structure is positioned inside the outer honeycomb structure, with both structures sharing the same axial space. The inner structure has cells that are radially inward of the outer structure's cells, creating a concentric arrangement that maximizes filtering surface area within a compact radial footprint, thereby reducing pressure loss without increasing overall device volume.
Solution Approach 2:
The patent transitions from a single-layer honeycomb structure to a dual-layer concentric honeycomb structure, utilizing the radial dimension more efficiently. By stacking honeycomb structures in concentric layers rather than extending them linearly, the design increases the effective filtering area in three-dimensional space without proportionally increasing the axial length or radial footprint, thus reducing pressure loss while maintaining compact dimensions.
2Loss of time
If the catalyst is disposed directly under the engine to activate it early, then catalyst activation temperature is achieved quickly, but the device complexity increases
Solution Approach 1:
The patent combines the exhaust gas treatment function with the catalyst support function into a single integrated honeycomb structure. The honeycomb walls are impregnated with catalyst material, eliminating the need for separate catalyst substrates or additional components. This integration maintains simplicity in device structure while enabling rapid catalyst activation by positioning the catalytically active surfaces directly in the exhaust flow path.
Solution Approach 2:
The honeycomb structure serves multiple functions simultaneously: it provides structural support, defines the flow channels, and supports the catalyst material. This multi-functionality reduces the number of separate components needed, simplifying the overall device while enabling rapid catalyst activation through direct exposure to hot exhaust gases.
3Reliability
If a mat is used to hold the catalyst carrier, then the catalyst is securely held, but the pressure loss increases
Solution Approach 1:
The patent removes the mat component entirely from the catalyst carrier structure. Instead of using a mat to hold the catalyst, the catalyst is directly impregnated onto the honeycomb wall surfaces. This extraction of the mat element eliminates the additional flow resistance it would create, reducing pressure loss while maintaining catalyst security through chemical bonding to the honeycomb structure.
Solution Approach 2:
The patent utilizes the porous structure of the honeycomb walls to hold the catalyst material. The porous walls provide large surface area for catalyst impregnation while maintaining open channels for exhaust flow. This eliminates the need for blocking mats, as the porous structure itself provides both catalyst support and flow pathways, reducing pressure loss while securing the catalyst.
Data Source
AI summary
An exhaust gas treating device includes a honeycomb structure including an inner honeycomb structure body including a honeycomb substrate having porous inner partition walls and a circumferential wall disposed at a circumference of the honeycomb substrate, an outer honeycomb structure body disposed at a position which surrounds a part of a circumference of the inner honeycomb structure body and is away from the inner inflow end face, and plugging portions; and a can member storing the honeycomb structure. The can member includes an inflow tube and a barrel portion which is continuous with the inflow tube, and in the barrel portion an outlet is formed, the honeycomb structure is stored in the can member in a state of having a clearance between a second end face and the can member and having a clearance between the outer outflow end face and the can member.