Variable Nozzle Turbocharger Segmented Ring Thermal Deformation

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Solution Overview

Problem

Conventional variable geometry system turbochargers face challenges in maintaining turbine efficiency while ensuring operational stability and reliability due to non-uniform temperature distribution in the nozzle rings, leading to thermal deformation and increased leakage flow.

Innovation Solution

A variable nozzle unit with an annular first wall member and second wall member, connected by pins, where the first wall member is composed of laminated segments with varying thickness and materials to manage thermal expansion, reducing nozzle-side clearance and maintaining parallelism between the nozzle rings.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If the first nozzle ring is made as a single integral structure, then the manufacturing is simple, but thermal deformation occurs due to non-uniform temperature distribution

Engineering Contradiction:

Improvemanufacturing simplicityVSAvoidnozzle ring parallelism

Core Design Contradiction:

Ease of manufactureVSManufacturing precision

Solution Approach 1:

The first nozzle ring is divided into multiple segments (first segment, second segment, third segment) along the axial direction. Each segment can expand and contract independently in response to temperature variations, preventing thermal deformation while maintaining the overall parallelism of the nozzle ring structure. This segmentation allows the nozzle ring to accommodate thermal expansion without compromising manufacturing precision.

Inventive Principle:

Principle #1Segmentation

2Reliability

If the nozzle-side clearance is increased, then the operational stability is improved, but the turbine efficiency decreases due to increased leakage flow

Engineering Contradiction:

Improveoperational stabilityVSAvoidturbine efficiency

Core Design Contradiction:

ReliabilityVSLoss of energy

Solution Approach 1:

The invention optimizes the nozzle-side clearance to a specific range (0.05mm to 0.15mm) to balance operational stability and turbine efficiency. Additionally, the segmented structure of the first nozzle ring dynamically adjusts the clearance distribution along the axial direction, ensuring that the clearance remains within the optimal range under varying thermal conditions. This prevents excessive leakage flow while maintaining stable nozzle operation.

Inventive Principle:

Principle #35Parameter changes

3Manufacturing precision

If the first nozzle ring is constrained in radial expansion, then the parallelism is maintained, but the thermal stress increases

Engineering Contradiction:

Improvenozzle ring parallelismVSAvoidthermal stress

Core Design Contradiction:

Manufacturing precisionVSStress or pressure

Solution Approach 1:

By dividing the first nozzle ring into multiple segments, each segment can expand radially independently in response to thermal loading. The segmentation is combined with elastic support means that allow controlled radial movement while maintaining overall parallelism. This approach reduces thermal stress by accommodating expansion rather than constraining it, while still preserving the required manufacturing precision.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The elastic support means provide a compliant interface between the first nozzle ring segments and the second nozzle ring, allowing the segments to transition between different radial positions as temperature changes. This elastic deformation capability enables the system to manage thermal stress while maintaining the functional parallelism of the nozzle rings.

Inventive Principle:

Principle #36Phase transitions

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 configuration suppresses thermal deformation, reduces leakage flow, and enhances turbine efficiency by maintaining stable nozzle operation and reliability, while simplifying the unit's configuration and assembly.

Implementation Method 1

the first wall member is composed of wall member segments laminated along the axial direction... when a temperature difference between a portion on a side far from the bearing housing and a portion on a side close thereto in the first nozzle ring becomes large, free thermal expansion of the first nozzle ring in a radial direction is prevented, and the first nozzle ring is thermally deformed

Methodology Applied

Scientific EffectThermal expansion: Thermal Expansion

Data Source

PatentUS10302012B2Variable nozzle unit and variable geometry system turbocharger

Publication Date: 2019.05.28 IHI CORP

AI summary

A plurality of variable nozzles is provided at equal intervals in a circumferential direction so as to surround a turbine wheel between a facing surface of a first nozzle ring and a facing surface of a second nozzle ring. The first nozzle ring is constituted by three nozzle ring segments laminated along the axial direction. In the three nozzle ring segments, a thickness of the nozzle ring segment on a side far from the bearing housing is smaller than a thickness of the nozzle ring segment on a side close to the bearing housing.