Radial-Mixing EGR Mixer for Compact Engine Packaging
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Solution Overview
Problem
Conventional EGR mixers require long mixing lengths to achieve acceptable mixing quality, which is difficult to package and inefficient for compact applications.
Innovation Solution
A radial-mixing EGR mixer with a convergent air supply passage, a mixing tube containing a nozzle and mixing element, and a divergent portion to increase pressure, facilitating efficient mixing of exhaust gas recirculation with air in a relatively short distance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional axial mixers are used for EGR mixing, then mixing quality can be achieved through diffusion and dispersion, but the mixing length becomes excessively long (L/d>10)
Solution Approach 1:
The patent transitions from axial mixing (one-dimensional flow along the mixer axis) to radial mixing (two-dimensional flow pattern where EGR is injected radially into the air stream). This dimensional change creates intense mixing action perpendicular to the main flow direction, achieving thorough mixing in a much shorter axial length while maintaining mixing quality.
Solution Approach 2:
The patent employs a jet injection mechanism where high-velocity EGR is injected radially into the air stream, creating a jet-induced mixing zone. This pneumatic approach uses the kinetic energy of the injected gas to drive mixing, eliminating the need for long diffusion paths required by passive axial mixing designs.
2Manufacturing precision
If long mixing lengths are used to achieve acceptable mixing quality, then mixing performance is improved, but packaging becomes difficult for most applications
Solution Approach 1:
By introducing radial injection perpendicular to the main flow direction, the patent creates a compact mixing zone that achieves thorough mixing without extending the axial length. This dimensional approach to mixing allows the mixer to fit within compact engine bay spaces while maintaining effective mixing performance.
3Device complexity
If axial mixing based on diffusion and dispersion is used, then the structure is simple, but the mixing efficiency is low requiring L/d>10
Solution Approach 1:
The patent uses jet injection where high-velocity EGR is injected radially into the air stream, creating turbulent mixing through momentum exchange. This pneumatic mixing mechanism achieves rapid and thorough mixing in a compact zone, dramatically improving mixing efficiency compared to passive diffusion-based axial mixers while adding only moderate structural 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 radial-mixing EGR mixer achieves thorough mixing of exhaust gas recirculation with air in a shorter distance, reducing emissions and improving packaging efficiency compared to conventional axial mixers.
Implementation Method 1
exhaust gas recirculation passage within the convergent portion includes a nozzle having a terminal end
Implementation Method 2
A mixing element is disposed in the mixing tube
Implementation Method 3
a divergent portion is arranged downstream adjoining the mixing tube to increase the pressure of the mixture after the mixing tube
Data Source
AI summary
A radial-mixing exhaust gas recirculation mixer is disclosed having an air supply passage having a convergent portion. An exhaust gas recirculation passage within the convergent portion includes a nozzle having a terminal end. A mixing tube is arranged downstream from the air supply passage and at least a portion of the exhaust gas recirculation passage. A mixing element is disposed in the mixing tube. In one example, a divergent portion is arranged downstream adjoining the mixing tube to increase the pressure of the mixture after the mixing tube. In one example, the exhaust gas recirculation mixer is arranged within an engine such that the air supply passage is in fluid communication with an intake manifold. The exhaust gas recirculation passage is in fluid communication with an exhaust manifold to recirculate a portion of exhaust gas to the intake manifold.