EGR Mixer Aperture Segmentation for Flow Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The flow characteristics of exhaust gas in existing EGR mixers affect the efficiency of mixing with ambient air, limiting the effectiveness of NOx emission reduction in turbocharged internal combustion engines.
Innovation Solution
An EGR mixer with an outer and inner wall defining a cavity, featuring a plurality of apertures with decreasing diameters and specific angular orientations, and offset walls to enhance mixing and control flow, pressure, and EGR rate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional EGR mixer design is used, then structure is simple, but mixing efficiency is insufficient and pressure loss is high
Solution Approach 1:
The mixer body is segmented into multiple functional zones: an exhaust gas inlet section, a mixing chamber with multiple apertures arranged in specific patterns, and an air outlet section. The apertures are segmented into different rows with varying diameters and orientations, creating distinct flow paths that enhance mixing efficiency while maintaining a relatively simple overall structure.
Solution Approach 2:
Different regions of the mixer have specialized characteristics: the apertures in different rows have different diameters (larger in first row, smaller in second row), different orientations (angular positions varied by 45 degrees between rows), and different spacing from the inlet. This local variation in aperture quality optimizes the mixing process at different stages while keeping the basic mixer structure simple.
2Productivity
If aperture diameters are uniform, then manufacturing is easier, but flow control and mixing efficiency are reduced
Solution Approach 1:
The apertures are designed with non-uniform diameters based on their position: the first row of apertures has a larger diameter than the second row. This local variation in aperture quality enables better control over EGR flow rates and mixing efficiency at different stages of the mixing process, while the systematic pattern maintains manufacturing feasibility.
3Productivity
If apertures are oriented randomly, then manufacturing is simpler, but flow characteristics and mixing efficiency are poor
Solution Approach 1:
Each aperture is oriented at a specific angular position relative to the mixer inlet, with angles varied systematically between rows (45 degrees difference). This local optimization of aperture orientation improves flow characteristics and mixing efficiency by directing exhaust gas flow in specific patterns, while the systematic angular arrangement maintains manufacturing precision requirements.
4Productivity
If mixing chamber volume is increased, then mixing efficiency improves, but pressure loss increases
Solution Approach 1:
The mixing chamber incorporates multiple apertures arranged in different rows rather than a single large opening, segmenting the flow paths. This segmentation allows the exhaust gas to mix with fresh air through multiple distributed pathways, improving mixing efficiency while maintaining lower pressure loss compared to a single large-volume chamber design.
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 EGR mixer improves NOx emissions reduction and EGR mixing efficiency by maintaining constant flow and minimizing pressure loss, thereby enhancing EGR rate and flow.
Implementation Method 1
The flow characteristics of exhaust gas as it enters and moves through the EGR mixer affect the efficiency of the mixing of the exhaust gas with ambient air
Implementation Method 2
the inner wall and the outer wall are offset in relation to each other such that a distance between the inner wall and the outer wall progressively decreases from a point adjacent the exhaust gas inlet to a radially opposite side of the cavity
Implementation Method 3
The exhaust gas is typically mixed with fresh air in an EGR mixer prior to introduction into the intake manifold
Implementation Method 4
exhaust gas recirculation (EGR)... take exhaust gas from a point downstream of the exhaust of the turbocharger exhaust turbine to the turbocharger compressor
Data Source
AI summary
The present invention provides an exhaust gas recirculation mixer for use with a long route (i.e., low pressure) EGR system adapted for use in a turbocharged internal combustion engine. The mixer comprises an outer wall and an inner wall defining a cavity therebetween, a chamber defined within the inner wall, an exhaust gas inlet on the outer wall, and apertures of varying dimensions disposed within the inner wall so that exhaust gas enters the mixer in a controlled flow through the exhaust gas inlet, through the cavity, and through the apertures into the chamber for mixture with ambient air.