Cantilevered Flow Distributing Element for Exhaust Aftertreatment
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Solution Overview
Problem
Existing exhaust aftertreatment systems for internal combustion engines face challenges in efficiently mixing reductants with exhaust gas, utilizing catalyst or filter surface area effectively, and maintaining structural durability while minimizing backpressure.
Innovation Solution
The implementation of a cantilevered flow distributing element with a baffle plate and collar, featuring specific aperture configurations and attachment zones, which enhances flow uniformity, structural rigidity, and reduces backpressure by optimizing the flow distribution within the exhaust aftertreatment system.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a flow distributing element is used to mix reductant with exhaust gas and spread flow over catalyst surface, then mixing efficiency and catalyst utilization are improved, but structural durability and resistance to thermal expansion/contraction deteriorate
Solution Approach 1:
The flow distributing element is segmented into a baffle plate and a separate collar component. The collar is attached to the baffle plate at multiple discrete attachment nodes distributed around its circumference, rather than as a single rigid connection. This segmentation allows different parts to move independently during thermal expansion and contraction, reducing stress concentrations and improving structural durability while maintaining mixing efficiency.
2Strength
If a rigid flow distributing element is used to maintain structural stability, then structural durability is improved, but resistance to thermal expansion and contraction deteriorates
Solution Approach 1:
The collar is attached to the baffle plate at multiple discrete attachment nodes rather than along its entire circumference. This creates localized rigid connections at the attachment nodes for structural stability, while the unattached portions of the collar can flex and move to accommodate thermal expansion and contraction. The local quality of rigidity at attachment points combined with flexibility in unattached regions resolves the contradiction between structural stability and thermal expansion resistance.
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 the mixing efficiency of reductants with exhaust gas, maximizes the utilization of catalyst or filter surface area, enhances structural durability, and minimizes backpressure, leading to improved emissions reduction and extended system life.
Implementation Method 1
The cantilevered collar includes a second plurality of aperture. The second plurality of apertures may be orientated substantially perpendicular to the first plurality of apertures
Implementation Method 2
The baffle plate includes a first plurality of apertures permitting exhaust gas to flow from the end chamber to the catalyst
Implementation Method 3
A mixer or flow distributing element is typically provided for mixing the injected reductant or hydrocarbon with the exhaust gas upstream of a catalyst or filter
Data Source
AI summary
An exhaust aftertreatment system may include a housing, an aftertreatment device, and a cantilevered flow distributing element. The housing receives exhaust gas output from an engine and has a main body and an exhaust gas inlet that is angled relative to the main body. The flow distributing element is disposed within the housing upstream of the exhaust aftertreatment device and includes a baffle plate and a collar. The baffle plate is attached to an inner wall of the main body. The collar may include a plurality of first apertures, a downstream axial edge and an upstream axial edge. A portion of the downstream axial edge may abut an upstream-facing surface of the baffle plate. The baffle plate may have a plurality of second apertures extending through the upstream-facing surface. The collar may extend across and partially block at least some of the second apertures.