Variable-Nozzle Turbine Radial Locator Design
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Variable-geometry turbochargers face challenges in maintaining radial centering of the variable vane mechanism due to high temperatures and thermal stresses, leading to potential plastic deformation and assembly complexities.
Innovation Solution
The use of elastically deformable metallic locators with undulating, C-shaped, S-shaped, or pin-based designs to radially locate the nozzle ring relative to the center housing, mitigating plastic deformation and ensuring concentricity with the turbine wheel, even at high temperatures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a rigid locator is used to radially locate the nozzle ring, then radial positioning precision is improved, but plastic deformation occurs under thermal stress at high temperatures
Solution Approach 1:
The locator is designed with elastic deformability, changing its mechanical parameter from rigid to flexible, allowing it to deform elastically under thermal stress rather than plastically, thus maintaining positioning precision while withstanding high temperatures
Solution Approach 2:
The locator transitions from a static rigid structure to a dynamic elastic structure that can adapt its shape in response to thermal expansion and contraction, maintaining continuous radial positioning while absorbing thermal stresses
2Ease of operation
If the variable vane mechanism is located between the turbine housing and center housing, then exhaust gas flow control is improved, but thermal stress and temperature gradients increase
Solution Approach 1:
The elastic locator acts as an intermediary element between the hot turbine housing and the cooler center housing, absorbing thermal stresses and protecting the variable vane mechanism from excessive thermal loading while maintaining its positioning function
3Stability of the object's composition
If the locator is preloaded circumferentially, then radial location stability is improved, but elastic deformation capacity is reduced
Solution Approach 1:
The locator is designed with partial preloading, applying just enough circumferential force to ensure stable radial positioning while retaining sufficient elastic deformability to handle thermal expansion and contraction without loss of function
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
These locator designs provide improved radial location and reduced risk of plastic deformation, maintaining concentricity and enhancing the stability and assembly of the variable-nozzle turbine, thus improving the control and efficiency of the turbocharger.
Implementation Method 1
an elastically deformable locator disposed between the first surface of the center housing and the opposing third surface of the nozzle ring
Data Source
Figure 1
Figure 1A~1B
Figure 2
AI summary
A turbocharger having a variable-nozzle turbine formed by pivotable vanes supported by a nozzle ring includes an elastically deformable locator disposed between a radially outwardly facing surface of the center housing and an opposing surface of the nozzle ring. In one embodiment the locator is a metallic ring having a radially undulating waveform shape that repeats a plurality of times about a circumference of the locator. In another embodiment the locator is a metallic ring having a C-shaped cross-section in a radial-axial plane. In still another embodiment the locator is a metallic ring having an S-shaped cross-section in a radial-axial plane. In a further embodiment the locator is a plurality of circumferentially spaced, radial locator pins affixed in the center housing and received in radial slots formed in the nozzle ring, the pins restraining the nozzle ring circumferentially and axially, but allowing thermal expansion of the nozzle ring.