Statorless Axial Turbine Housing with Meridional Scroll Segmentation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing turbocharger designs face inefficiencies due to communication or 'cross talk' between separate exhaust passages, which limits the effectiveness of pulse separation in multi-piston reciprocating engines, particularly in small gasoline engines where conventional axial turbines are ineffective.
Innovation Solution
A meridionally divided turbine housing with a statorless axial turbine design, featuring two separate exhaust gas streams directed into a turbine wheel with no inlet stators, utilizing a circumferentially and radially extending dividing wall to maintain separation and optimize flow paths, and a heat shroud to direct gases axially into the turbine wheel.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a conventional axial turbine with inlet stators is used, then flow guidance into the turbine blades is improved, but the turbine becomes ineffective for small gasoline engines and axial loading increases
Solution Approach 1:
The patent removes the inlet stators (nozzles) from the turbine assembly, extracting the flow guidance function to a separate component - the meridionally divided scroll. This allows the turbine wheel to operate without axial loading from stators while still achieving proper flow guidance through the scroll's geometry, making it effective for small gasoline engines.
Solution Approach 2:
The scroll is divided into meridional segments that surround the turbine wheel, with each segment having a separate outlet. This segmentation provides flow guidance without requiring inlet stators, eliminating axial loading while maintaining effective flow direction for small engine applications.
2Productivity
If separate exhaust passages are used for pulse separation, then efficiency is improved, but cross talk between passages occurs
Solution Approach 1:
The scroll is segmented into separate meridional passages, each with its own outlet positioned at different radial locations. This segmentation maintains pulse separation efficiency while the specific geometry and outlet positioning minimize cross-talk between the separate exhaust passages.
3Ease of operation
If inlet stators are used to guide flow, then flow direction is improved, but axial loading on the turbine increases
Solution Approach 1:
The flow direction control function is extracted from the inlet stators and transferred to the meridionally divided scroll. The scroll's geometry and outlet positioning provide flow direction control without imposing axial loading on the turbine wheel, as the stators are completely removed from the design.
4Object-generated harmful factors
If a meridionally divided scroll with separate outlets is used, then cross talk is minimized, but device complexity increases
Solution Approach 1:
The flow guidance function traditionally performed by inlet stators is merged with the scroll structure itself. The meridionally divided scroll with its segmented passages and strategically positioned outlets provides both flow guidance and cross-talk minimization in a single integrated component, reducing overall device complexity despite the segmented 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
This design enhances efficiency by minimizing cross talk, improving valve charge exchange, reducing boost pressure requirements, and allowing for more efficient energy extraction with reduced axial loading, leading to higher overall system efficiency and cost-effective manufacturing.
Implementation Method 1
separate first and second outlets... through which the exhaust gases are fed in an axial direction to an axial turbine wheel
Implementation Method 2
exhaust gases are fed... to an axial turbine wheel. The first outlet is generally radially outward of the second outlet such that the exhaust gas from the first outlet is fed to a radially outer portion of the inlet side of the axial turbine wheel and the exhaust gas from the second outlet is fed to a radially inner portion of the inlet side of the axial turbine wheel
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A statorless axial turbine for a turbocharger has a turbine housing assembly defining a meridionally divided scroll extending circumferentially and surrounding the turbine wheel, the meridionally divided scroll defining a first scroll extending substantially fully about the turbine wheel and a separate second scroll extending substantially fully about the turbine wheel. The turbine housing assembly defines a separate inlet for each of the first and second scrolls through which a separate exhaust gas stream is received, and separate first and second outlets for each of the first and second scrolls, respectively, through which the respective exhaust gas streams are fed into an inlet side of the turbine wheel generally in an axial direction of the turbine wheel.