Wastegate Valve Flap Sealing Geometry for Thermal Distortion
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Solution Overview
Problem
Conventional exhaust gas turbochargers with wastegate valve devices face issues with thermal distortion and wear, leading to inefficient sealing and increased manufacturing costs due to complex curved sealing faces, which also generate noise from flap vibrations.
Innovation Solution
A wastegate valve device with a sealing face formed by a sequence of coaxially arranged conical peripheral surfaces that merge continuously, providing a convex shape to improve sealing and reduce manufacturing complexity, while axial stops limit displacement to maintain sealing effectiveness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a flat sealing face is used on the flap, then the design is simple, but sealing performance deteriorates under thermal distortion and wear
Solution Approach 1:
The sealing face of the flap is designed with a convex curvature instead of a flat surface. This curved geometry allows the sealing face to maintain contact with the valve seat under thermal distortion and wear conditions, improving sealing reliability while keeping the overall design relatively simple.
2Reliability
If a curved sealing face is used to compensate for thermal distortion, then sealing performance improves, but manufacturing complexity and costs increase
Solution Approach 1:
The convex curved sealing face is implemented using standard machining operations that can form spherical or cylindrical surfaces. This approach achieves the necessary compensation for thermal distortion and wear while remaining compatible with conventional manufacturing processes, avoiding excessive complexity.
3Reliability
If play is mounted on the spindle arm to compensate for wear, then reliability improves, but noise from flap vibrations increases
Solution Approach 1:
The convex curved sealing face compensates for wear and thermal distortion through its geometry, allowing the flap to maintain sealing contact without requiring excessive play in the spindle arm. This reduces the amplitude of flap vibrations and the resulting noise while preserving sealing reliability.
Data Source
AI summary
A charging device may include a turbine housing and a wastegate valve device. The wastegate valve device may include a flap, a spindle arm, a wastegate spindle, an axial stop, and a lever arm non-rotatably attached to the wastegate spindle. The wastegate spindle may be rotatably mounted in a bushing disposed on the turbine housing. A wastegate duct may be disposed in the turbine housing. The wastegate duct may have a duct aperture enclosed by a valve seat. The duct aperture, when in a closed state, may be closed by the flap of the wastegate valve device. A sealing face of the flap may be defined by a sequence of at least two conical peripheral surfaces arranged next to one another and each having a different inclination.