Split Nozzle Ring for Turbocharger EGR and Exhaust Flow Control
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Solution Overview
Problem
Existing turbocharger designs require multiple asymmetric twin-volute turbine housing configurations to achieve optimal exhaust gas recirculation (EGR) and turbine performance, which is inefficient and not adaptable to various applications.
Innovation Solution
A symmetric twin-volute turbine housing with a nozzle ring featuring fixed vanes that can be configured to create an asymmetric twin-volute effect by directing exhaust gas at an optimum angle, allowing for adjustable exhaust gas backpressure and turbine output through the use of a split nozzle ring with different vane counts on each side.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple asymmetric twin-volute turbine housing configurations are used to achieve optimal EGR and turbine performance, then EGR efficiency and turbine output are improved, but device complexity and manufacturing cost increase
Solution Approach 1:
The nozzle ring is segmented into multiple sections with different numbers of vanes (e.g., first section with 9 vanes, second section with 13 vanes). This segmentation allows each section to be optimized for specific functions: one section promotes EGR by creating higher backpressure, while another section maintains turbine output. The segmented design achieves the performance of multiple asymmetric configurations without requiring multiple complete turbine housing designs.
Solution Approach 2:
Different sections of the nozzle ring have different local qualities in terms of vane count and geometry. The first section has fewer vanes to allow higher exhaust gas flow and backpressure for EGR, while the second section has more vanes to maintain turbine wheel driving force. This local differentiation enables simultaneous optimization of EGR efficiency and turbine performance within a single symmetric housing.
2Stress or pressure
If asymmetric twin-volute turbine housing is used to optimize EGR, then exhaust gas backpressure is increased for EGR, but turbine output and engine response are reduced
Solution Approach 1:
The nozzle ring is divided into functional sections where the first section (with fewer vanes) creates higher backpressure to promote EGR, while the second section (with more vanes) maintains sufficient flow area to drive the turbine wheel effectively. This segmentation resolves the contradiction by distributing different pressure requirements to different sections rather than applying a uniform asymmetric design throughout.
Solution Approach 2:
While the overall housing is symmetric, the nozzle ring introduces controlled asymmetry through different vane counts in different sections. The first section has fewer vanes creating asymmetric flow patterns that increase backpressure for EGR, while the second section compensates with more vanes to maintain turbine power. This localized asymmetry within a symmetric structure balances EGR requirements with turbine performance.
3Adaptability or versatility
If multiple turbine housing configurations are used to meet different application requirements, then adaptability is improved, but manufacturing cost and inventory complexity increase
Solution Approach 1:
The symmetric twin-volute turbine housing with a multi-section nozzle ring serves multiple functions that previously required different housing configurations. The same basic housing can be adapted to different applications by modifying the nozzle ring's vane distribution, allowing a single housing design to meet various EGR and performance requirements across different engine applications, thereby reducing manufacturing costs and inventory complexity.
Solution Approach 2:
The nozzle ring design allows for dynamic adaptation to different applications through variable vane counts in different sections. Rather than manufacturing multiple rigid housing configurations, the system can be adapted by adjusting the nozzle ring's geometric parameters (vane counts, angles, positions), providing application flexibility with a single base housing design.
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
Enables efficient exhaust gas recirculation and turbine performance optimization with a single symmetric twin-volute design, improving engine response and fuel economy while meeting emissions standards, and allowing for flexible adaptation to different applications.
Implementation Method 1
The turbine converts the exhaust gas into mechanical energy to drive the compressor. The exhaust gas enters the turbine housing at an inlet, flows through a scroll or volute, and is directed into the turbine wheel located in the center of the turbine housing.
Implementation Method 2
This pressure drop is converted by the turbine into kinetic energy to drive the turbine wheel. Energy transfer from kinetic energy into shaft power takes place at the turbine wheel, which is designed so that nearly all the kinetic energy is converted by the time the exhaust gas reaches the turbine outlet.
Implementation Method 3
The nozzle ring is sandwiched between the bearing housing and the turbine housing and the vanes direct the exhaust gas against the turbine wheel at an optimum angle.
Implementation Method 4
In order to recirculate exhaust gas into the intake manifold, the exhaust gas must be at a pressure that is greater than the pressure of the intake air. However, if the pressure of the exhaust gas is excessive, the exhaust gas creates backpressure on the engine that is detrimental to overall fuel efficiency and performance.
Data Source
AI summary
A turbocharger (10) for an internal combustion engine includes a symmetric twin-volute turbine housing (12) having first and second volutes (16, 18). A turbine wheel (22) is disposed within the symmetric twin-volute turbine housing (12) for rotation about a turbocharger axis (R1). A nozzle ring (42, 58) is fixedly secured to the symmetric twin-volute turbine housing (12). The nozzle ring (42, 58) includes a plurality of fixed vanes (44, 62, 66) disposed circumferentially around the turbocharger axis (R1). The plurality of fixed vanes (44, 62, 66) form nozzle passages leading from at least one of the first and second volutes (16, 18) to the turbine wheel (22) for directing exhaust gas against the turbine wheel (22) at an optimum angle.