Turbocharger Wastegate Port Wall Thermal Decoupling
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Solution Overview
Problem
Conventional turbocharger turbine housings experience performance degradation and failure due to thermal deformation, leading to poor sealing of the wastegate channel, as the wastegate port wall is subjected to the hottest exhaust gas stream, causing differential thermal expansion and relative movement between the valve element and the valve seat.
Innovation Solution
The wastegate port wall is positioned outside the exducer interior, thermally decoupling it from the turbine inlet wall, allowing for reduced thermal deformation and improved sealing by maintaining the wastegate port and bushing walls at a lower thermal expansion rate, thus enhancing the operational range and performance of the turbocharger.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the wastegate port wall is disposed inside the exducer interior, then the turbocharger structure is compact, but the wastegate port wall is subjected to the hottest exhaust gas stream causing greater thermal deformation and poor sealing
Solution Approach 1:
The wastegate port wall is extracted from the hot exhaust gas stream environment by positioning it outside the exducer interior. This separation removes the wastegate port wall from the thermal field, preventing thermal deformation while maintaining structural integrity and sealing performance.
Solution Approach 2:
The exducer shroud wall acts as an intermediary thermal barrier between the hot exhaust gas stream and the wastegate port wall. By positioning the wastegate port wall outside the exducer interior, the exducer shroud wall mediates the thermal exposure, protecting the wastegate components from excessive heat while maintaining structural compactness.
2Temperature
If the wastegate port wall is subjected to hot exhaust gas stream, then the turbocharger can handle high exhaust temperatures, but differential thermal expansion causes relative movement between valve element and valve seat
Solution Approach 1:
The wastegate port wall and associated components are extracted from the high-temperature exhaust gas stream by positioning them outside the exducer interior. This eliminates differential thermal expansion between components exposed to different temperatures, maintaining precise alignment between the valve element and valve seat while still allowing the turbocharger to handle high exhaust temperatures through the turbine section.
Solution Approach 2:
Different parts of the turbocharger are assigned different thermal environments based on their functional requirements. The turbine section remains exposed to high temperatures for efficient exhaust energy utilization, while the wastegate port wall is positioned in a cooler region to maintain dimensional stability and sealing precision.
3Adaptability or versatility
If the bushing wall and wastegate port wall thermally deform at different rates, then the turbocharger can operate under varying thermal conditions, but the valve element cannot properly engage the valve seat to seal the wastegate channel
Solution Approach 1:
The wastegate port wall is extracted from the high-temperature thermal field by positioning it outside the exducer interior. This ensures that the wastegate components experience minimal thermal deformation and maintain consistent dimensional relationships, enabling reliable valve element-to-valve seat engagement and sealing across the entire operating range of the internal combustion engine.
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 configuration ensures accurate valve element movement to seal the wastegate channel, allowing the turbine wheel to reach rotational targets and the internal combustion engine to meet performance standards by reducing relative displacement and improving sealing efficiency.
Implementation Method 1
the wastegate port wall is disposed outside of the exducer interior such that the wastegate port wall and the bushing wall are configured to be thermally decoupled from the turbine inlet wall
Implementation Method 2
thermal deformation of the turbine housing can cause relative movement between various features of the turbocharger
Data Source
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AI summary
A turbocharger includes a turbine housing. The turbine housing includes a turbine inlet wall defining an inlet passage, an exducer shroud wall defining an exducer interior, a turbine outlet wall defining an outlet passage, a wastegate port wall defining a wastegate channel, and a bushing wall coupled to the wastegate port wall and defining a bushing boss extending along a bushing axis, and a valve seat disposed about the wastegate channel. The turbocharger also includes a wastegate assembly. The wastegate assembly includes a valve element engageable with the valve seat. The wastegate port wall is disposed outside of the exducer interior such that the wastegate port wall and the bushing wall are configured to be thermally decoupled from the turbine inlet wall and such that relative displacement between the valve seat and the bushing axis is reduced during operation of the turbocharger.