Sliding Vane Turbine Nozzle for Boost Pressure Control
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Solution Overview
Problem
Variable geometry turbines for turbochargers face challenges in maintaining efficient boost pressure control across a range of engine operating conditions, as existing solutions like swing nozzle vanes and annular sliding rings either compromise on cross-sectional area or suffer from expansion losses at varying exhaust flows.
Innovation Solution
An annular turbine nozzle with a central axis and a sliding nozzle vane, where the sliding vane moves tangentially within the nozzle, allowing for independent adjustment of the cross-sectional area and incident angle to maintain optimal efficiency across engine conditions, reducing expansion losses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of moving object
If an annular sliding ring is used to vary the cross-section of channels, then the cross-sectional area can be controlled, but expansion losses occur when exhaust gas expands from the small turbine nozzle channel to the larger turbine inlet at small exhaust flows
Solution Approach 1:
The annular sliding ring is segmented into multiple independent sliding vanes that can be individually positioned. Each vane has a sliding surface that contacts the stationary vane, allowing precise control of the channel cross-sectional area. This segmentation enables better matching of the channel exit area to the turbine inlet area, reducing expansion losses while maintaining control capability.
Solution Approach 2:
The sliding vanes are designed with specific local geometries including sliding surfaces, leading edges, and trailing edges optimized for their positions. The vanes create localized flow control zones where the gas flow is directed efficiently. This local optimization ensures that at each position, the channel geometry is tailored to minimize expansion losses while maintaining the desired cross-sectional area control.
2Shape
If swing nozzle vanes are used to pivot within the turbine nozzle, then the angle of incidence can be controlled, but the cross-sectional area and angle of incidence cannot be varied independently creating a trade-off
Solution Approach 1:
The nozzle geometry is segmented into stationary vanes and independent sliding vanes. The sliding vanes can move axially relative to the stationary vanes, creating multiple degrees of freedom in the flow path geometry. This segmentation allows the cross-sectional area and angle of incidence to be controlled independently, as the sliding vane position and orientation can be adjusted separately to achieve desired flow conditions.
Solution Approach 2:
The sliding vanes introduce dynamic adjustability to the nozzle geometry. By allowing the vanes to slide axially, the system can dynamically change both the cross-sectional area and the flow direction angle. This dynamic capability enables independent control of area and angle parameters, providing adaptability across different operating conditions without the trade-offs of fixed-geometry swing nozzle designs.
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 solution effectively controls boost pressure and maintains turbine efficiency over a wide range of engine operating conditions by minimizing expansion losses and optimizing gas flow, outperforming traditional variable geometry turbines.
Implementation Method 1
The sliding vane is positioned to slide in a direction substantially tangent to an inner circumference of the turbine nozzle. Thus, a desired angle of incidence may be substantially maintained over a range of engine operating conditions.
Implementation Method 2
expansion losses may be reduced as compared to a turbine nozzle with an annular sliding ring
Data Source
AI summary
Various systems and methods are described for a variable geometry turbine. In one example, a turbine nozzle comprises a central axis and a nozzle vane. The nozzle vane includes a stationary vane and a sliding vane. The sliding vane is positioned to slide in a direction substantially tangent to an inner circumference of the turbine nozzle and in contact with the stationary vane.