Variable Geometry Turbocharger Nozzle Vane Fin Axial Force Control
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Solution Overview
Problem
Nozzle vanes in variable geometry turbochargers experience axial force due to pressure differences, leading to potential wear when in contact with shroud or hub surfaces, and existing solutions do not effectively control this force.
Innovation Solution
A nozzle vane design featuring a fin on the pressure or suction surface, positioned within 0.6L from the trailing edge, with a length of 0.3L or more along the chord direction, and a deflection angle between -10° and 10°, to generate a controlled force in the rotational axis direction, reducing wear and pressure loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the nozzle vane is disposed close to the shroud surface or hub surface to control the exhaust gas flow, then the turbocharger performance is improved, but wear on the shroud surface, hub surface, or nozzle vane body increases due to contact friction
Solution Approach 1:
The fin acts as an intermediary element that generates a controlled force to counteract the pressure difference between the shroud side and hub side. This force pushes the nozzle vane body away from the shroud surface or hub surface, preventing direct contact and wear while allowing the nozzle vane to maintain its optimal position for exhaust gas flow control.
Solution Approach 2:
The invention changes the physical parameters of the exhaust gas flow by introducing the fin with specific geometric parameters (length X ≥ 0.3L, position within 0.6L from trailing edge, deflection angle -10° to 10°). These parameter changes create a force that counteracts the pressure difference, thereby controlling the axial position of the nozzle vane body and preventing wear.
2Stress or pressure
If communication holes are provided in the valve body to connect shroud side and hub side, then the pressure difference is reduced, but the force control on the nozzle vane becomes insufficient
Solution Approach 1:
Instead of uniformly reducing pressure difference throughout the valve body using communication holes, the invention applies a localized force generation mechanism through the fin. The fin is strategically positioned and dimensioned to generate a specific force in the axial direction at a critical location, providing precise force control rather than general pressure equalization.
3Force
If the fin is positioned closer to the leading edge to generate axial force, then the force generation is improved, but the exhaust gas flow velocity is reduced leading to increased pressure loss
Solution Approach 1:
The invention optimizes the parameters of the fin (position within 0.6L from trailing edge, length X ≥ 0.3L, deflection angle -10° to 10°) to achieve a balance between axial force generation and pressure loss reduction. By carefully selecting these parameters, the fin generates sufficient axial force while minimizing interference with the high-velocity exhaust gas flow near the trailing edge.
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 fin effectively controls the axial force on the nozzle vane, reducing wear and pressure loss while maintaining turbocharger performance, even at low opening degrees.
Implementation Method 1
the fin disposed on at least one of the pressure surface or the suction surface of the nozzle vane body applies a force to the nozzle vane body in a rotational axis direction of the nozzle vane, which intersects the flow of exhaust gas
Data Source
AI summary
A nozzle vane of a variable geometry turbocharger comprises: a nozzle vane body rotatably disposed in an exhaust gas passage defined between a shroud surface and a hub surface; and a fin disposed on at least one of a pressure surface or a suction surface of the nozzle vane body and disposed within a range of 0.6L from a trailing edge of the nozzle vane body, where L refers to a chord length of the nozzle vane body. The fin satisfies a relationship of 0.3L≤X, where X refers to a length of the fin along a chord direction of the nozzle vane body.