Variable Turbine Nozzle with Integrated Bypass for Turbocharger
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Solution Overview
Problem
Existing variable turbine nozzles for turbochargers either lack aerodynamic efficiency or mechanical simplicity, as they require multiple moving parts for flow regulation, and even fully open configurations may not allow sufficient flow passage.
Innovation Solution
A variable nozzle assembly with an integrated bypass that uses a fixed stator and a rotatable rotor with movable vanes to vary the nozzle flow area and bypass exhaust gas around the turbine wheel, requiring no additional parts beyond those needed for flow regulation, allowing for maximum or minimum flow passage depending on the rotor position.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If a sliding piston-type variable turbine nozzle is used to maximize flow area, then the throat area at turbine wheel inlet is maximized, but the flow restriction downstream cannot be reduced sufficiently
Solution Approach 1:
The variable nozzle is segmented into two functional components: a sliding piston that controls the throat area at the turbine wheel inlet, and a separate bypass valve that provides an alternative flow path around the turbine wheel. This segmentation allows independent control of the main flow path and bypass path, enabling the system to achieve maximum exhaust gas flow rate by opening both the piston to maximize throat area and the bypass valve to reduce downstream flow restriction.
2Ease of operation
If variable-vane nozzles with rotatable vanes are used for flow regulation, then aerodynamic performance is improved, but mechanical complexity increases due to substantial number of moving parts
Solution Approach 1:
The invention merges the functions of flow regulation and bypass control into a single integrated variable nozzle assembly. The sliding piston serves dual purposes: it controls the throat area of the main nozzle and simultaneously acts as the bypass valve by blocking or opening the bypass passage. This merging eliminates the need for separate bypass valve mechanisms, reducing the number of moving parts while maintaining aerodynamic performance through the piston's position-dependent flow control.
3Device complexity
If sliding piston-type variable nozzles are used, then mechanical simplicity is achieved, but aerodynamic performance deteriorates compared to variable-vane nozzles
Solution Approach 1:
The sliding piston is designed with multi-functionality: it serves as both the primary flow regulation mechanism for the main nozzle and the bypass valve. By positioning the piston at different axial locations, the system can achieve multiple flow control modes including full nozzle opening, partial opening, and bypass activation. This universal design maintains mechanical simplicity with a single moving part while achieving aerodynamic performance through clever geometric design of the piston and its interaction with the nozzle passages.
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 design achieves mechanical simplicity and efficient flow regulation with a single moving part, enabling maximum flow passage by bypassing the turbine wheel when needed, while maintaining aerodynamic performance without additional mechanical complexity.
Implementation Method 1
exhaust gas flows from the chamber through the bypass opening and through the bypass channel into the bore, bypassing the turbine wheel
Data Source
AI summary
A turbocharger with an exhaust gas-driven turbine includes a variable nozzle formed by a stator supporting fixed vanes and defining bypass openings, and a rotor supporting movable vanes and defining bypass channels. Each fixed vane overlaps with a movable vane by a varying extent dependent on rotational position of the rotor. In a fully open position of the rotor, the movable vanes have a maximum extent of overlap with the fixed vanes, and the bypass channels align with the bypass openings so that some of the exhaust gas flows through the aligned bypass openings and channels, bypassing the turbine wheel.