Turbocharger Wastegate Diffuser Reducing Exhaust Turbulence
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Solution Overview
Problem
Turbochargers face inefficiencies in fluid outflow due to turbulence and vibrations, particularly when the wastegate valve is open or closed, affecting engine performance and catalytic converter efficiency.
Innovation Solution
Incorporating a diffuser within the turbine housing outlet passage to separate gas flows from the turbine wheel and wastegate, minimizing turbulence and reducing vibrations by being either a single, self-supported piece with the housing or using snap features and Belleville springs for thermal growth accommodation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a wastegate arrangement is integrated into the turbine housing, then exhaust gas can be diverted around the turbine wheel to control boost pressure, but fluid outflow turbulence and vibrations increase affecting engine performance
Solution Approach 1:
A diffuser insert is introduced as an intermediary component between the turbine outlet and wastegate passage. This diffuser serves as a mediator that conditions the exhaust gas flow, reducing turbulence and vibrations before the gas enters the wastegate passage or exits the turbine housing, thereby resolving the harmful effects while maintaining wastegate functionality.
Solution Approach 2:
The diffuser insert is specifically positioned at the turbine outlet where turbulence is generated, providing localized flow conditioning. The insert has a specific geometry with a diffuser angle designed to gradually expand the flow, creating local quality improvements in the flow regime precisely where needed without affecting other parts of the system.
2Ease of manufacture
If the diffuser is made as a single self-supported piece with the housing, then manufacturing is simplified, but accommodation of thermal growth is limited
Solution Approach 1:
The diffuser insert is designed as a separate component that can expand and contract independently from the turbine housing. This separate construction allows each component to accommodate thermal growth independently, with the diffuser insert being retainable at its first end and free at its second end, enabling thermal expansion without constraining the housing or creating stress concentrations.
3Stability of the object's composition
If the diffuser insert is retained at both ends within the housing, then positioning is stable, but thermal growth accommodation is restricted
Solution Approach 1:
The diffuser insert is designed with asymmetric retention: fixed at the first end (upstream) and free to move axially at the second end (downstream). This dynamic configuration allows the insert to maintain stable positioning where needed while providing freedom for thermal expansion in the direction of exhaust flow, accommodating temperature changes without compromising positioning stability.
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 diffuser enhances fluid outflow behavior by reducing turbulence and vibrations, improving engine efficiency and catalytic converter performance across wastegate valve positions.
Implementation Method 1
Incorporating a diffuser within the turbine housing outlet passage to separate gas flows from the turbine wheel and wastegate, minimizing turbulence and reducing vibrations
Data Source
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Figure 10~14A
AI summary
A number of variations may include a turbine housing comprising a turbine body; an inlet passage and an outlet passage connected to the turbine body; a wastegate passage operatively connected to the outlet passage; a diffuser positioned within the outlet passage comprising at least one radial opening; wherein the first flow passage accepts fluid flow from the wastegate passage and the second flow passage accepts fluid flow from the turbine wheel; wherein a first end of the diffuser is attached to a first end of the turbine outlet and a second end of the diffuser is attached to a second end of the turbine outlet so that fluid flow from the first flow passage is directed into the second flow passage through the at least one radial opening before exiting the outlet passage, and wherein the at least one radial opening minimizes turbulence of fluid flow exiting the turbine housing.