Exhaust Catalyst Flow Zone for Uniform Heating
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Solution Overview
Problem
Existing exhaust aftertreatment systems for internal combustion engines face challenges in achieving improved light-off behavior and overall conversion efficiency, particularly with uncoated particle filters requiring larger three-way catalytic converters and increased precious metal usage, which complicates CO2 emission management.
Innovation Solution
An exhaust aftertreatment system with two catalytic converters and a particle filter, where the exhaust gas outlet of the first catalytic converter is spatially separated from the inlet of the second, forming a flow area that encases the first catalytic converter, enhancing heat exchange and catalytic conversion efficiency through uniform heating.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an uncoated particulate filter is used, then the three-way catalytic converter must be significantly larger to compensate for the lack of particulate conversion capability, but this increases device complexity and precious metal usage
Solution Approach 1:
The patent combines the particulate filter and three-way catalytic converter into a single integrated component where the filter elements themselves provide catalytic conversion capability through coating. This eliminates the need for a separate large catalytic converter, reducing device complexity while maintaining conversion efficiency.
Solution Approach 2:
The particulate filter is designed to perform multiple functions simultaneously: filtering particulates and converting gaseous components through the three-way catalyst coating on the filter elements. This multi-functionality allows one component to replace what would traditionally require separate components.
2Reliability
If a coated particulate filter is used, then particulate conversion is improved, but additional three-way catalytic converters are required for gaseous component conversion, increasing device complexity
Solution Approach 1:
The patent merges the particulate filtration function and gaseous component conversion function into a single integrated system. The three-way catalyst coating on the particulate filter elements provides both particulate capture and gaseous conversion capabilities, eliminating the need for additional separate catalytic converters.
Solution Approach 2:
The coated particulate filter elements serve as universal components that simultaneously perform particulate filtration and gaseous component conversion through their dual functionality, reducing the overall number of components required in the exhaust aftertreatment system.
3Speed
If the first three-way catalytic converter is located close to the engine, then light-off performance is improved, but heat distribution uniformity deteriorates
Solution Approach 1:
The patent segments the exhaust flow path into multiple zones around the catalytic converter, with flow channels distributed uniformly around the converter perimeter. This segmentation allows heat to be distributed more evenly across the catalyst surface while maintaining close proximity to the engine for rapid light-off.
Solution Approach 2:
The patent transitions from a single central exhaust flow path to a three-dimensional arrangement where exhaust gas flows through multiple channels surrounding the catalytic converter. This spatial distribution in multiple dimensions enables both rapid heating for light-off and uniform heat distribution across the catalyst surface.
4Reliability
If a larger three-way catalytic converter is used to compensate for uncoated filter, then conversion efficiency is maintained, but precious metal usage increases, affecting cost and CO2 emissions
Solution Approach 1:
The patent combines the catalytic conversion function with the particulate filter structure, applying the three-way catalyst coating directly to the filter elements. This integration allows the same precious metal coating to serve dual purposes: particulate capture and gaseous conversion, thereby reducing the total quantity of precious metals required compared to separate components.
Solution Approach 2:
The three-way catalyst coating on the particulate filter elements provides universal functionality for both particulate and gaseous conversion, maximizing the utilization of precious metals and reducing the total amount needed compared to dedicated separate components for each 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 improves light-off behavior and overall conversion efficiency, reduces the size of the first catalytic converter, and allows for cost-effective and package-neutral implementation, facilitating easier regeneration and reduced CO2 emissions.
Implementation Method 1
the flow around the first catalyst through the flow zone causes a temperature increase through heat exchange with the warm or hot exhaust gas
Implementation Method 2
allowing the corresponding catalytic chemical reactions to take place
Data Source
Figure 1~2
AI summary
The invention relates to an exhaust aftertreatment system (1) for an internal combustion engine with a first catalyst (10) which has a first exhaust inlet (11) for introducing the exhaust gas into the first catalyst (10) and an exhaust outlet (12) positioned opposite it, a second catalyst (30) arranged downstream relative to the first catalyst (10), which is flow-connected to the first catalyst (10) for the passage of the exhaust gas from the first catalyst (10) into the second catalyst (30) and comprises a second exhaust inlet (31), wherein the second exhaust inlet (31) is spatially spaced apart from the exhaust outlet (12) of the first catalyst (10). Furthermore, a particulate filter (50) is arranged downstream relative to the second catalyst (30), which is connected to the second catalyst (30) in a flow-through manner for the passage of exhaust gas from the second catalyst (30) into the particulate filter (50).A flow area (20) is formed adjacent to an outer surface (14) of the first catalyst (10), in which the exhaust gas flows from the exhaust gas outlet (12) to the second exhaust gas inlet (31) into the second catalyst (30).