Exhaust Diffuser Uniform Flow Distribution
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Solution Overview
Problem
In exhaust aftertreatment systems, achieving uniform flow distribution of exhaust gases to catalytic converters is challenging due to the shortening of distances between inlet ports and catalytic converters, especially when hydrocarbon dosing is used, and the piping configuration upstream affects flow uniformity, leading to inefficient treatment and reduced component lifespan.
Innovation Solution
An exhaust aftertreatment system with a diffuser element having a shell with proximal and distal portions, where the proximal portion has a larger open area than the distal portion, positioned between the inlet and catalytic converter to evenly distribute exhaust gases, ensuring uniform flow and restricted airflow through the distal portion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the distance between the exhaust inlet port and the catalytic converter is shortened to reduce system size, then the compactness is improved, but the flow uniformity deteriorates
Solution Approach 1:
A diffuser element is introduced as an intermediary component between the exhaust inlet port and the catalytic converter. This diffuser includes a proximal portion with a first open area and a distal portion with a second open area, where the first open area is 1.8-2.2 times the second open area. The diffuser redistributes the exhaust flow to achieve uniform flow distribution across the catalytic converter face despite the shortened distance, thus resolving the contradiction between compactness and flow uniformity.
2Productivity
If hydrocarbon dosing is used to distribute dosing material evenly, then the treatment efficiency is improved, but the flow distribution uniformity deteriorates
Solution Approach 1:
The diffuser element serves as a mediator that works in conjunction with hydrocarbon dosing. The diffuser's graduated open areas (first open area being 1.8-2.2 times the second open area) create a velocity profile that promotes even distribution of both exhaust gases and dosing material across the catalytic converter, maintaining treatment efficiency while ensuring flow distribution uniformity.
3Adaptability or versatility
If the piping configuration is modified to fit compact engine configurations, then the adaptability is improved, but the flow uniformity deteriorates
Solution Approach 1:
The diffuser element acts as a flow-conditioning intermediary that compensates for non-uniform flow patterns caused by various piping configurations. Regardless of how the exhaust inlet is connected to accommodate different engine layouts, the diffuser's proximal and distal portions with specific open area ratios (1.8-2.2:1) restore flow uniformity before the exhaust enters the catalytic converter, thus maintaining adaptability while ensuring flow uniformity.
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
The diffuser system ensures even distribution of exhaust gases to the catalytic converter, enhancing treatment efficiency and extending the operational life of the system by maintaining optimal flow uniformity and distribution, even in compact and non-linear configurations.
Implementation Method 1
The exhaust gases are diffused through a plurality of openings formed through a front side of the diffuser
Data Source
AI summary
An exhaust aftertreatment system includes a housing including first and second axial ends. An exhaust inlet is disposed adjacent the first axial end. An exhaust outlet is disposed adjacent the second axial end. A catalytic converter is disposed between the first and second axial ends. A diffuser is disposed inside the housing between the first axial end and the catalytic converter. The diffuser includes a shell in communication with the exhaust inlet. The shell includes proximal and distal portions and a front side facing the catalytic converter. The proximal and distal portions are substantially equal in frontal area. The proximal portion is adjacent the exhaust inlet and includes a first plurality of front side openings totaling a first open area and the distal portion includes a second plurality of front side openings totaling a second open area. The first open area is about 1.8-2.2 times the second.