Exhaust Mixing Assembly with Swirl Mixer for Reactant Evaporation
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Solution Overview
Problem
Existing mixing assemblies for exhaust gas treatment units in internal combustion engine exhaust systems do not achieve effective mixing of exhaust gas and reactant with a simple structural design, leading to inefficient interaction and mixing.
Innovation Solution
A mixing assembly with a mixer at the entrance of the mixing section, featuring a core flow channel and a jacket flow channel, where the reactant delivery arrangement is positioned within the core flow channel, and a mixer peripheral wall with multiple exhaust gas inlet openings generating swirl flow, enhancing turbulence and interaction with an heated inner wall for efficient mixing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a mixer is added at the upstream end section of the mixing path, then the mixing efficiency of exhaust gas and reactant is improved, but the device complexity increases
Solution Approach 1:
The mixer is integrated into the existing mixing assembly structure, combining the mixing function with the exhaust gas flow path. The mixer circumferential wall is positioned within the mixing section, merging multiple functions (flow division, mixing, and reactant delivery) into a unified structure rather than adding separate independent components.
Solution Approach 2:
The mixer circumferential wall serves multiple functions: it defines the mixer volume for turbulent mixing, provides mounting positions for exhaust gas inlet openings, and works in conjunction with the core flow channel and shell flow channel for flow division. This multi-functionality reduces the need for additional separate components.
2Manufacturing precision
If the mixer circumferential wall is positioned engaging the core flow channel, then reactant delivery precision is improved, but the manufacturing complexity increases
Solution Approach 1:
The mixing section is divided into distinct functional zones: the mixer volume defined by the mixer circumferential wall, the core flow channel for reactant delivery, and the shell flow channel for exhaust gas flow. This segmentation allows each component to be manufactured and positioned independently with specific tolerances, making the engaging position between the mixer circumferential wall and core flow channel achievable through standard manufacturing processes.
3Productivity
If multiple exhaust gas inlet openings are provided in the mixer circumferential wall, then the turbulence and mixing interaction are enhanced, but the manufacturing complexity increases
Solution Approach 1:
Instead of adding multiple separate mixer units, the solution provides multiple exhaust gas inlet openings distributed around the mixer circumferential wall in the circumferential direction. This utilizes the dimensional space available in the circumferential direction to enhance mixing interaction through multiple flow entry points, achieving improved mixing without proportionally increasing overall device complexity.
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 design ensures thorough mixing of exhaust gas and reactant with increased dwell time and interaction, supported by the swirl flow and heating, resulting in improved mixing efficiency and reactant evaporation, enhancing the interaction with the inner surface for better exhaust gas treatment.
Implementation Method 1
This turbulence, generated by the mixer, results in a longer residence time in the mixing section.
Implementation Method 2
This heating device warms the inner wall, causing the reactant, which strikes it as a spray or droplet, to evaporate.
Implementation Method 3
This heating device warms the inner wall, causing the reactant, which strikes it as a spray or droplet, to evaporate.
Implementation Method 4
due to the centrifugal forces acting in the swirl flow, an increased interaction with the inner surface of the inner wall, which is heated by the second exhaust gas partial flow, occurs
Data Source
Figure 1
Figure 2
AI summary
A mixing assembly for an exhaust gas treatment unit for an exhaust system of an internal combustion engine for mixing exhaust gas emitted by the internal combustion engine with a reactant, comprising a reactant discharge arrangement (14) and, in an exhaust gas flow direction downstream with respect to the reactant discharge arrangement (14), a mixing section (12) for mixing exhaust gas with reactant discharged into the exhaust gas by the reactant input arrangement (14), wherein the mixing section (12) comprises a core flow channel (34) extending in the direction of a longitudinal axis (L) of the mixing section and through which a first exhaust gas partial flow (T1) can flow, and a shell flow channel (36) surrounding the core flow channel (34) and separated from it by an inner wall (30) and through which a second exhaust gas partial flow (T2) can flow.wherein the reaction agent discharge arrangement (14) for the discharge of reaction agent is arranged essentially into the core flow channel (34) and/or the first exhaust gas partial flow (T1), is characterized in that a mixer (38) is provided at an upstream end region (22) of the mixing section (12).