Ceramic Carrier Body with Segmented Cell Density for Exhaust Aftertreatment
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Solution Overview
Problem
Existing exhaust gas aftertreatment systems face challenges in achieving a balance between reducing start emissions and maintaining mechanical stability, particularly when incorporating a particulate filter function with ceramic carrier bodies, as the addition of a central bypass borehole compromises stability and metal carrier bodies cannot achieve a particulate filter function with partly closed flow channels.
Innovation Solution
A ceramic carrier body with an inner region of lower cell density and an outer region of higher cell density, where the outer region has a coating for HC adsorption and potentially a particulate filter function, while the inner region provides mechanical support and can have a catalytic function, avoiding the stability issues associated with central bypass bores and allowing for efficient adsorption and catalytic conversion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a central bypass borehole is added to the ceramic carrier body to enable particulate filter function, then the particulate filter function is achieved, but the mechanical stability of the carrier body deteriorates
Solution Approach 1:
The carrier body is divided into an inner region and an outer region with different cell densities. The inner region has lower cell density (100-200 cpsi) providing mechanical support, while the outer region has higher cell density (400-900 cpsi) providing filtration function. This segmentation allows both structural integrity and filtration capability without requiring a central bypass borehole.
Solution Approach 2:
Different regions of the carrier body are assigned different cell densities tailored to their specific functions. The inner region uses lower cell density for mechanical stability, while the outer region uses higher cell density for enhanced filtration and HC adsorption. This local differentiation optimizes both structural and functional performance.
2Strength
If metal carrier bodies are used instead of ceramic, then mechanical stability is improved, but the particulate filter function with partly closed flow channels cannot be achieved
Solution Approach 1:
The patent utilizes the inherent porosity and structural flexibility of ceramic materials to create a monolithic carrier body with varied cell densities. The ceramic structure allows for partially closed flow channels in the outer region that enable particulate filtration while maintaining overall mechanical stability through the denser inner region support structure.
3Adaptability or versatility
If the cell density is increased throughout the carrier body to improve filtration, then the filtration performance is improved, but the exhaust gas backpressure increases
Solution Approach 1:
The carrier body features localized high cell density in the outer region (400-900 cpsi) where filtration is needed, while the inner region maintains lower cell density (100-200 cpsi) to provide flow pathways that reduce backpressure. This spatial differentiation allows high filtration performance without excessive pressure buildup.
Solution Approach 2:
The flow path is segmented into an inner region with lower resistance for pressure management and an outer region with higher density for filtration. This segmentation creates a pressure management strategy where the inner region acts as a low-resistance bypass that prevents excessive backpressure while the outer region performs the filtration function.
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 configuration enhances the mechanical stability of the ceramic carrier body, reduces exhaust gas backpressure, and enables effective adsorption of unburnt hydrocarbons while allowing for a particulate filter function, thereby improving overall emission reduction and system efficiency.
Implementation Method 1
at least the outer region of the carrier body has a coating, the coating of the outer region having an HC adsorber function for a reversible adsorption of unburnt hydrocarbons
Implementation Method 2
the inner region provides mechanical support and can have a catalytic function
Implementation Method 3
the flow channels of the inner and outer regions that pass axially through the carrier body have a catalytic coating (washcoat)
Implementation Method 4
due to the exothermic heat release, the inner region is heated relatively quickly and thus also heats the surrounding outer region
Data Source
AI summary
An exhaust gas aftertreatment component includes a ceramic carrier body with a plurality of axial flow channels, wherein the carrier body has an inner region and an outer region, which radially surrounds the inner region. A cell density of the carrier body is smaller in the inner region than a cell density in the outer region. At least the outer region of the carrier body has a coaling, wherein the coating of the outer region has an HC adsorber function for a reversible adsorption of unburnt hydrocarbons. An exhaust gas system, which is equipped with such an exhaust gas aftertreatment component, and a vehicle, which has such an exhaust gas system are also provided.