Twin-Vaned Nozzle Ring Assembly for Turbocharger
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Solution Overview
Problem
Meridionally divided turbocharger turbine housings suffer from shaft motion issues due to out-of-phase exhaust gas pulses and mixing losses, as the exhaust gas flow from each scroll impinges on less than the full axial width of the turbine blade leading edges, affecting turbine efficiency.
Innovation Solution
A twin-vaned nozzle ring assembly is designed to direct separate exhaust gas streams from two scrolls in an interleaved fashion around the circumference of the turbine wheel, using a method that includes injection molding and assembly with pins to ensure full utilization and separation of exhaust manifold pressure pulses, thereby mitigating shaft motion and mixing losses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If meridionally divided turbine housing is used, then shaft motion is reduced, but turbine efficiency decreases due to mixing losses
Solution Approach 1:
The turbine housing is divided into two separate scrolls that succeed one another in the axial direction, with each scroll occupying substantially a full circumference. This segmentation allows independent exhaust gas flow paths while maintaining full circumferential coverage, preventing mixing losses and preserving turbine efficiency while reducing shaft motion.
Solution Approach 2:
The division transitions from radial/sector-based separation to axial/meridional separation, where scrolls succeed one another in the axial direction rather than angularly. This dimensional change allows each scroll to occupy full circumference while maintaining separation, eliminating the trade-off between shaft stability and efficiency.
2Reliability
If sector-divided turbine housing is used, then flow separation is improved, but unwanted shaft motion is induced
Solution Approach 1:
The turbine housing is segmented into two separate scrolls divided by a partition wall extending axially. This segmentation provides complete flow separation between exhaust streams while the axial arrangement and full-circumference coverage prevent the out-of-phase pulse induction that causes shaft motion in sector divisions.
Solution Approach 2:
Instead of dividing the turbine housing radially into sectors (conventional approach), the invention divides it meridionally into scrolls that succeed in the axial direction. This inverted approach reverses the cause-effect relationship, achieving flow separation without inducing shaft motion.
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 nozzle ring assembly effectively reduces unwanted turbocharger shaft motion and enhances turbine efficiency by ensuring that each exhaust gas stream impinges on the full extent of the turbine blade leading edges, maintaining good flow isolation and optimizing the utilization of pressure pulses.
Implementation Method 1
The component is made from a moldable material, such as by an injection molding process
Data Source
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AI summary
A twin-vaned nozzle ring (30) for a turbine nozzle of a turbocharger nozzle ring is made by assembling the nozzle ring (30) from three separately formed parts. A center part (60) includes a first ring (40) of circumferentially spaced first vanes (42) and a second ring (50) of circumferentially spaced second vanes (52), the first and second rings being axially spaced and integrally joined to each other. The first vanes are circumferentially offset from the second vanes, and exits from the first vane passages (44) are radially aligned with and circumferentially interleaved with exits from the second vane passages (54). First and second side walls are provided as separate parts. Finally, the first side wall (46, 56) is joined to a distal or outer face of the first ring, and the second side wall is joined to a distal face of the second ring to complete the assembly.