Turbine Housing Diffuser Space Geometry for Turbocharger Efficiency
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Solution Overview
Problem
Conventional turbocharger designs experience energy losses due to recirculation of exhaust gas between non-equal pressure volutes, which occurs at critical points in the engine cycle when most energy is available to power the turbine wheel, leading to inefficiency.
Innovation Solution
A turbine housing design with a diffuser space between the volutes and the turbine wheel, where the diffuser space has a greater axial extent downstream than upstream, directing exhaust gas from one volute towards its corresponding axial end and reducing the likelihood of recirculation, thereby improving efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If exhaust gas flows freely between volutes without a diffuser space, then the structure is simpler, but recirculation occurs causing energy losses
Solution Approach 1:
A diffuser space is introduced as an intermediary element between the volutes and turbine wheel. This diffuser space acts as a mediator that redirects exhaust gas flow from high-pressure volutes away from low-pressure volutes, preventing recirculation. The diffuser space includes a divider wall with a tip positioned at a specific distance from the turbine wheel, creating a controlled flow path that eliminates the harmful recirculation effect while maintaining structural efficiency.
2Productivity
If the diffuser space has greater axial extent downstream than upstream, then recirculation is reduced, but the housing becomes more complex
Solution Approach 1:
The diffuser space is designed with non-uniform axial extent, where the downstream portion has a greater axial extent than the upstream portion. This local variation in geometry creates different flow characteristics in different regions: the greater downstream axial extent directs exhaust gas away from the low-pressure volute inlet, preventing recirculation, while the upstream portion maintains appropriate flow reception. This localized geometric optimization achieves high efficiency without requiring complex structures throughout the entire housing.
3Ease of manufacture
If the divider wall tip is positioned closer to the turbine wheel, then the diffuser space is reduced, but manufacturing is easier
Solution Approach 1:
The design specifies an optimal range for the distance between the divider wall tip and the turbine wheel, and for the axial extent of the diffuser space. By carefully selecting these geometric parameters within specified ranges, the invention achieves a balance between manufacturing feasibility and flow control effectiveness. The parameters are optimized to provide sufficient diffuser space for flow redirection while maintaining manufacturability through reasonable dimensional tolerances and geometric simplicity.
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 proposed geometry effectively reduces the risk of recirculation, enhancing efficiency by ensuring that exhaust gas from one volute does not interrupt the flow from the other, particularly at points in the engine cycle where energy is most available, resulting in significant efficiency benefits.
Implementation Method 1
The diffuser space has a downstream portion having a greater axial extent than an upstream portion of the diffuser space, thereby directing exhaust gas from one volute towards a corresponding axial end of the diffuser space
Data Source
Figure 1~2
Figure 3(a)~3(b)
Figure 4
AI summary
A turbine housing defining a pair of volutes with respective outlets divided by a divider wall, includes a diffuser space in the gas flow path between the volutes and the turbine wheel. The diffuser space has an upstream portion having a smaller axial extent than a downstream portion of the diffuser space. The widening of the diffuser space tends to direct exhaust gas entering the diffusion space from at least one side of the divider wall towards the corresponding axial end of the diffuser space. Thus reduces the tendency of this gas to interrupt the flow into the diffuser space of exhaust gas from the other inlet volute.