Binary Flow Turbine Scroll Valve Control for Engine Dilution
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Solution Overview
Problem
Engine systems face limitations in engine dilution due to combustion stability constraints, where further dilution is not deliverable despite the need for it, especially at high engine loads, leading to degraded performance in boosted engine systems with binary flow turbines.
Innovation Solution
Adjusting the scroll valve coupled to the inlet of a multi-scroll exhaust turbine based on engine dilution requests to manage exhaust residuals, allowing for increased or decreased dilution by coordinating with wastegate adjustments, thereby extending the range of engine operating conditions for improved performance and fuel economy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If EGR valves are opened to increase engine dilution, then emissions decrease and fuel economy improves, but combustion stability deteriorates and torque delivery is limited
Solution Approach 1:
The patent applies dynamics by making the scroll valve position variable rather than fixed. The scroll valve is dynamically adjusted based on operating conditions to control exhaust flow distribution between scrolls, enabling the system to adaptively manage residual delivery and maintain combustion stability across different load and speed conditions while achieving desired dilution levels.
Solution Approach 2:
The patent changes the parameter of exhaust flow distribution by adjusting the scroll valve position. This parameter change allows control over the amount of residual exhaust gas delivered to the engine, enabling the system to optimize the balance between dilution (for emissions reduction) and residual management (for combustion stability) under varying operating conditions.
2Reliability
If EGR valves are closed to reduce engine dilution, then combustion stability improves, but further dilution cannot be provided when needed
Solution Approach 1:
The scroll valve provides dynamic control capability that allows the system to extend its operational range. By dynamically adjusting the scroll valve position, the system can provide additional dilution control beyond what fixed EGR valve positions can achieve, enhancing adaptability to different operating conditions while maintaining combustion stability.
Solution Approach 2:
The scroll valve adds multi-functionality to the exhaust system by enabling control over exhaust flow distribution in addition to the EGR valve functions. This universal control mechanism allows the system to achieve both combustion stability and extended dilution range, making the system more versatile across different operating conditions.
3Quantity of substance
If scroll valve is closed to increase exhaust manifold pressure for HP-EGR flow, then dilution capability improves, but residuals management becomes challenging
Solution Approach 1:
The patent uses parameter changes by adjusting the scroll valve position to control exhaust flow distribution. This enables independent management of exhaust manifold pressure (for HP-EGR flow) and residual delivery (through selective scroll blocking), allowing the system to achieve desired dilution quantities while maintaining appropriate residual levels for combustion stability.
Data Source
AI summary
Methods and systems are provided for adjusting the opening of a scroll valve of a binary flow turbine. Scroll valve adjustments are used at different engine operating conditions to improve engine performance and boost response. Scroll valve adjustments are coordinated with wastegate and EGR valve adjustments for improved engine control.