Twin-Scroll Turbine Flow Transfer Valve for Exhaust Pressure Management
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Solution Overview
Problem
Supercharged internal combustion engines face a conflict in optimizing exhaust-gas discharge systems for both low engine speeds and high engine speeds, as grouping cylinders for impulse supercharging at low speeds degrades turbine efficiency at higher speeds, while increasing exhaust-gas volume for ram supercharging at high speeds impairs low-end torque.
Innovation Solution
A two-channel turbine with a longitudinally displaceable flow transfer valve that couples and separates channels based on the valve's position, allowing for adjustable fluidic coupling and exhaust blow-off, enabling adaptation of exhaust-gas volume to different operating conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If cylinders are grouped to realize impulse supercharging at low engine speeds, then low-end torque and operating behavior are enhanced, but turbine efficiency degrades at higher speeds due to pressure fluctuations
Solution Approach 1:
The exhaust system configuration is made dynamically adjustable through a control valve that can switch between two states: connected (for impulse supercharging at low speeds) and disconnected (for ram supercharging at high speeds). This allows the system to adapt its structure based on operating conditions, resolving the contradiction between low-end torque enhancement and turbine efficiency preservation.
Solution Approach 2:
The system changes the connectivity parameter of the exhaust system based on engine speed. At low speeds, the control valve connects the two cylinder groups to enable impulse supercharging and enhance low-end torque. At high speeds, the valve disconnects the groups to reduce pressure fluctuations and maintain turbine efficiency, thus resolving the performance trade-off across different operating ranges.
2Loss of energy
If exhaust-gas volume is increased upstream of the turbine to smooth pressure fluctuations for ram supercharging at high speeds, then turbine efficiency improves, but low-end torque is impaired
Solution Approach 1:
The exhaust system configuration is made dynamically adjustable through a control valve that can switch between two states: connected (for impulse supercharging at low speeds) and disconnected (for ram supercharging at high speeds). This allows the system to adapt its structure based on operating conditions, resolving the contradiction between low-end torque enhancement and turbine efficiency preservation.
Solution Approach 2:
The system changes the connectivity parameter of the exhaust system based on engine speed. At low speeds, the control valve connects the two cylinder groups to enable impulse supercharging and enhance low-end torque. At high speeds, the valve disconnects the groups to reduce pressure fluctuations and maintain turbine efficiency, thus resolving the performance trade-off across different operating ranges.
3Device complexity
If a single exhaust system configuration is used for all operating conditions, then device complexity is reduced, but performance optimization across the entire operating range is compromised
Solution Approach 1:
The exhaust system incorporates a dynamically controllable valve mechanism that adjusts the connectivity between cylinder groups based on operating conditions. This dynamic adjustment capability enables performance optimization across the entire operating range while adding only minimal complexity through a single control valve and associated control logic.
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 solution allows for optimized operation across the entire operating range by fine-tuning the exhaust-gas flow and pressure conditions, enhancing engine performance and reducing residual gas issues that lead to knocking problems.
Implementation Method 1
a position of the valve relative to the duct controls the extent of fluidic coupling between channels
Implementation Method 2
a two-channel turbine, comprising a longitudinally displaceable flow transfer valve arranged within a flow transfer duct that couples a first channel of the two-channel turbine to a second channel
Implementation Method 3
impulse supercharging may be employed to enhance the operating behavior of the engine. Impulse supercharging advantageously uses the dynamic wave produced during charge exchange for supercharging
Implementation Method 4
During the further course of charge exchange, the pressures in the cylinder and in the exhaust line are equalized
Data Source
AI summary
A supercharged engine and operating methods thereof are described for adjusting an extent of fluidic coupling between separate channels of a two-channel turbine. In one particular example, a longitudinally displaceable flow transfer valve is arranged for movement lateral to the exhaust airflow that provides coupling between the channels, a position of the flow transfer valve within a flow transfer duct controlling the extent of fluidic coupling in addition to the rate of exhaust-gas flow through a blow-off line that conducts airflow past a rotor of the two-channel turbine. In this way, the flow transfer valve according to the present disclosure advantageously allows for adjusting a mode of supercharging based on one or more engine conditions to control the extent of fluidic coupling using a simplified valve arrangement.