Variable Geometry Turbine Communication Holes for Nozzle Vane Wear
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Solution Overview
Problem
The repetition of unnecessary movement and wear of nozzle vanes in variable geometry turbines due to external forces and engine vibrations is a significant issue, leading to potential wear and reliability concerns.
Innovation Solution
A variable geometry turbine design with a link mechanism and communication holes in the hub-side member to increase the pressure difference between the nozzle flow path and link compartment, applying an axial force on the nozzle vanes to suppress unnecessary movement and wear.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a clearance is provided between the nozzle shaft and nozzle mount to enable nozzle vane movement, then the nozzle vane can rotate to control exhaust gas flow, but the nozzle vane experiences unnecessary movement and wear due to external forces such as gravity and engine vibration
Solution Approach 1:
The patent introduces a counterweight member that generates a counterbalancing force to offset the effects of gravity and vibration on the nozzle vane. The counterweight member is configured to rotate together with the nozzle vane and applies a force through the link mechanism that counteracts the external forces, thereby preventing unnecessary movement and wear of the nozzle vane while maintaining its rotation capability for flow control.
2Adaptability or versatility
If the number of movable components is increased to achieve variable geometry functionality, then the turbocharger can adapt to wide engine speed ranges, but the reliability decreases due to more components that can fail
Solution Approach 1:
The link mechanism serves multiple functions: it connects the actuator to the nozzle vane for rotation control, provides a counterbalancing force through the counterweight member, and supports the nozzle vane to prevent wear. By making the link mechanism multi-functional, the patent reduces the need for additional separate components, thereby maintaining adaptability while improving reliability.
3Adaptability or versatility
If exhaust gas is heated or more movable components are added to enable wide engine speed operation, then the variable geometry turbocharger can meet diverse engine requirements, but the reliability is significantly reduced
Solution Approach 1:
The counterweight member in the link mechanism provides a counterbalancing force that offsets gravity and vibration effects on the nozzle vane. This allows the system to maintain reliability by preventing wear and unnecessary movement, while still achieving adaptability through the variable geometry capability enabled by the actuator-controlled nozzle vane rotation.
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 design effectively suppresses unnecessary movement and wear of nozzle vanes by enhancing the pressure difference and axial force, improving the reliability and longevity of the turbine components.
Implementation Method 1
an opening of the at least one communication hole on a nozzle flow path side is formed on an inner side in a radial direction with respect to a leading edge of each of the plurality of nozzle vanes in a case where each of the plurality of nozzle vanes is in a fully open state
Data Source
AI summary
Provided are a variable geometry turbine and a turbocharger with the same. The variable geometry turbine is provided with a turbine impeller, a housing, a plurality of nozzle vanes, and a link mechanism. Inside the housing, a link compartment in which the link mechanism is accommodated is formed, the link compartment being separated from a nozzle flow path by a hub-side member having a hub side surface defining the nozzle flow path. The link mechanism and each of the plurality of nozzle vanes are coupled together via a nozzle shaft penetrating through the hub-side member. The hub-side member has at least one communication hole providing communication between the nozzle flow path and the link compartment. When each of the plurality of nozzle vanes is fully opened, the opening of the at least one communication hole on the nozzle flow path side is formed on the inner side radially of the turbine impeller than the leading edge of each of the plurality of nozzle vanes.