Elliptical Turbocharger Diffuser Connection Section
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The existing turbocharger diffuser design faces challenges in improving efficiency without increasing size, as the enlarged flow passage sectional area can lead to exhaust gas separation and vortex formation, reducing efficiency.
Innovation Solution
The diffuser design features a connection section with an elliptical flow passage sectional shape, where the long axis elongates towards the downstream side, and the central axis deviates from the body section center, allowing exhaust gas to spread and reduce flow rate, while the Coanda effect helps the gas follow the inner surface, preventing separation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the flow passage sectional area of the diffuser is steeply enlarged to secure space for the bypass passage and waste gate valve, then the space for components is improved, but the exhaust gas flow separates from the inner surface or forms vortices, reducing diffuser efficiency
Solution Approach 1:
The connection section employs an elliptical cross-section with the long axis oriented in the downstream direction, utilizing the longitudinal dimension to accommodate flow spreading without requiring excessive radial expansion. This dimensional reorientation allows compact packaging of the diffuser while maintaining adequate flow area for bypass passage and waste gate valve integration.
Solution Approach 2:
The connection section uses an asymmetric elliptical shape rather than a circular cross-section, with the long axis extended in the downstream direction. This asymmetric geometry creates favorable flow spreading characteristics that reduce separation and vortex formation, thereby maintaining diffuser efficiency while providing sufficient space for auxiliary components.
2Speed
If the flow passage sectional area is increased to reduce exhaust gas flow rate, then the flow rate reduction is improved, but the diffuser size increases
Solution Approach 1:
The elliptical connection section with long axis in downstream direction exploits the longitudinal dimension to achieve flow rate reduction through extended flow path, avoiding the need for large radial expansion that would increase overall diffuser size.
Solution Approach 2:
The diffuser geometry parameters are optimized by employing an elliptical cross-section with specific aspect ratio and orientation, changing the shape parameters to achieve favorable flow characteristics and compact sizing simultaneously.
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 design enhances the efficiency of the diffuser and turbocharger by reducing the flow rate and preventing gas separation, thereby improving performance without increasing the diffuser's size.
Implementation Method 1
exhaust gas flowing through the connection section is likely to spread in the long-axis direction of the ellipse of the connection section when the exhaust gas flows from the connection section into the body section
Implementation Method 2
the flow of the exhaust gas flowing into the body section is likely to follow the inner surface of the body section due to the Coanda effect, and it is possible to curb occurrence of separating off and the like of the exhaust gas
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
A diffuser includes a connection section (84) and a body section (85). The connection section (84) extends from an outlet of turbine rotor blades. The body section (85) is connected to an end of the connection section (84) on a downstream side and has a larger flow passage sectional area than the connection section (84). The shape of the flow passage sectional surface of the connection section (84) is formed into a circle at an outlet (710) of the turbine rotor blades (71) and is formed into an ellipse at an inlet (85i) of the body section (85). The shape of the flow passage sectional surface of the connection section (84) is further formed to be gradually enlarged in a long-axis direction of the ellipse from the outlet (710) of the turbine rotor blades (71) toward the inlet (85i) of the body section (85).