Variable Geometry Ported Shroud Turbocharger Surge Control
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Solution Overview
Problem
Turbochargers face performance issues and compressor degradation due to fluctuations in flow rate and pressure ratio, leading to noise disturbances and surge conditions, which existing technologies struggle to effectively mitigate.
Innovation Solution
A variable geometry ported shroud system is introduced, featuring a compressor wheel surrounded by a shroud with a single port that can be adjusted by a ring to control airflow, allowing recirculation of air and optimizing compressor efficiency by opening or closing the port based on operating conditions to extend the turbocharger's effectiveness and prevent surge.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the port in the shroud is opened to allow air recirculation, then the surge margin is improved and compressor stability is enhanced, but the compressor efficiency decreases due to reduced airflow through the compressor wheel
Solution Approach 1:
The port in the shroud is made variable in geometry through the use of an adjustable ring that can shift axially to change the port's cross-sectional area. This dynamic adjustment allows the system to optimize between surge margin and compressor efficiency based on operating conditions, resolving the contradiction by making the port opening controllable rather than fixed
Solution Approach 2:
The cross-sectional area of the port is changed as a controllable parameter to balance surge protection and efficiency. By adjusting the ring position, the port area is modified to allow more air recirculation when surge risk is high, and reduce recirculation when efficiency is prioritized, thus dynamically resolving the technical contradiction
2Productivity
If the port is closed to increase airflow through the compressor, then compressor efficiency and power output are improved, but surge conditions may occur under low flow conditions
Solution Approach 1:
The adjustable ring enables dynamic control of the port opening, allowing the system to close the port for efficiency when operating conditions permit, and open it when surge risk increases, thus adaptively resolving the contradiction between efficiency and surge resistance
Solution Approach 2:
The system uses feedback from operating conditions (such as mass flow rate and pressure ratio) to control the ring position, automatically adjusting the port opening to prevent surge while maintaining efficiency, resolving the contradiction through closed-loop control
3Reliability
If multiple ports are added to the shroud to improve surge margin, then compressor stability is enhanced, but the device complexity and manufacturing difficulty increase
Solution Approach 1:
Instead of adding multiple separate ports, the invention segments the single port's cross-sectional area through the adjustable ring, creating multiple flow paths within a single port structure. This reduces complexity while maintaining the ability to control airflow for surge prevention
Solution Approach 2:
The single adjustable port serves multiple functions: it can be fully open for maximum surge protection, fully closed for maximum efficiency, or partially open for intermediate conditions. This multi-functionality eliminates the need for multiple separate ports, reducing complexity while maintaining 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 variable geometry ported shroud system enhances compressor efficiency, widens the compressor map, and mitigates surge by adjusting airflow, thereby improving the turbocharger's performance and extending its operating range while maintaining compact design without additional plumbing.
Implementation Method 1
a ring configured to move axially to adjust a restriction of the port
Implementation Method 2
Turbochargers function by compressing intake air in a compressor via a turbine operated by exhaust gas flow
Implementation Method 3
compressor efficiency may be increased by allowing recirculation of air from the compressor air inlet to the bypass passage via an open port
Data Source
AI summary
Various methods and systems are provided for a variable geometry ported shroud for a turbocharger. In one example, a compressor system includes a compressor housing defining an air inlet, a shroud, and a bypass passage, a compressor wheel housed in the compressor housing and surrounded by the shroud, only a single port passing through the shroud and fluidically coupled to the bypass passage, and a ring configured to move axially to adjust a restriction of the port.