Partitioned Volute Nozzle With Variable Vanes for Exhaust Pulse Use
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Solution Overview
Problem
Turbochargers face inefficiencies in utilizing exhaust pulse energy due to pulsating flow from internal combustion engines, particularly in gasoline engines, leading to issues like knocking sensitivity and reduced turbine performance.
Innovation Solution
A variable nozzle turbine (VNT) combined with a twin flow housing is used to improve fuel efficiency by maintaining flow separation and optimizing exhaust gas flow to the turbine wheel, utilizing a mechanism with pivotable vanes to adjust nozzle throats and channels based on engine conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a conventional fixed nozzle turbine is used, then the structure is simple, but exhaust pulse energy is not effectively utilized and turbine performance is reduced
Solution Approach 1:
The patent applies the dynamics principle by replacing fixed nozzles with movable vanes that can pivot to adjust nozzle throat areas. The vanes are positioned on a rotating carrier that can change its orientation relative to the turbine wheel, allowing the nozzle geometry to dynamically adapt to varying exhaust flow conditions and engine RPMs, thereby optimizing turbine performance across different operating ranges.
Solution Approach 2:
The patent implements parameter changes by varying the nozzle throat area through vane rotation angles. The control system adjusts the carrier rotation and vane positions to modify the effective flow area of each nozzle, changing flow parameters such as mass flow rate, velocity, and pressure distribution to match optimal values for different engine operating conditions.
2Speed
If exhaust flow is not optimized, then engine response at higher RPMs is poor, but optimizing exhaust flow increases sensitivity to knocking
Solution Approach 1:
The patent applies local quality by providing different nozzle characteristics for different exhaust gas channels. Each nozzle can be independently adjusted via its own vane and carrier mechanism, allowing localized optimization of flow parameters for specific cylinders or exhaust streams. This enables tailored flow distribution that can enhance high-RPM response in certain channels while managing pressure waves to reduce knocking sensitivity in others.
Solution Approach 2:
The patent utilizes periodic action by synchronizing the rotation of the vane carrier with the engine firing order and exhaust pulse frequency. The vanes are positioned to open and close in a periodic sequence that matches the exhaust gas arrival patterns, creating constructive interference that enhances exhaust pulse energy utilization and improves engine response while controlling pressure wave timing to mitigate knocking.
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
Enhances turbine performance and fuel efficiency by better utilizing exhaust pulse energy, reducing knocking sensitivity and improving engine response at higher RPMs.
Implementation Method 1
maintaining flow separation and optimizing exhaust gas flow to the turbine wheel
Implementation Method 2
at least one set of adjustable variable geometry nozzle vanes that define nozzle throats that direct flow of exhaust gas from at least one of the exhaust gas channels to the turbine wheel space
Data Source
Figure 1
Figure 2A~2C
Figure 3
AI summary
An assembly can include an exhaust gas turbine housing including an inner wall and an outer wall that define a first exhaust gas channel and a second exhaust gas channel to a turbine wheel space where the inner wall includes an inner wall end at the turbine wheel space and the outer wall includes an outer wall end at the turbine wheel space; a first flow body disposed adjacent to the inner wall end; a second flow body disposed adjacent to the outer wall end; and at least one set of adjustable variable geometry nozzle vanes that define nozzle throats that direct flow of exhaust gas from at least one of the exhaust gas channels to the turbine wheel space, where at least one of the first flow body and the second flow body includes a concave trailing surface that is defined in part by an arc of a circle.