Turbine Diffuser Segmentation for Turbocharger Maintenance

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Solution Overview

Problem

Conventional axial turbines in exhaust gas turbochargers require tedious and time-consuming maintenance due to the rigid coupling of the turbine diffuser with the gas outlet housing, making it difficult to remove the rotor block as a unit, and are prone to deformations affecting turbine efficiency.

Innovation Solution

Mechanically decoupling the turbine diffuser from the outer housing by attaching it to the radially inner housing parts via specially designed struts, creating a hood diffuser assembly that allows the rotor, turbine diffuser, and nozzle ring to be removed together, and using a semi-static choke seal to prevent leakage flows.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of repair

If the turbine diffuser is rigidly coupled to the gas outlet housing, then the structure is simple and sealed, but maintenance is tedious and time-consuming due to difficulty in removing the rotor block

Engineering Contradiction:

Improvemaintenance easeVSAvoidstructural complexity

Core Design Contradiction:

Ease of repairVSDevice complexity

Solution Approach 1:

The turbine diffuser is segmented from the gas outlet housing by introducing a movable connection interface. The diffuser can be separated from the housing by pulling it axially outward, allowing the rotor block to be removed as a unit without detaching the diffuser from the housing. This segmentation enables easy maintenance while maintaining structural integrity during operation.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The connection between the turbine diffuser and gas outlet housing is changed from rigid to dynamic/movable. The diffuser is designed with axial movability relative to the housing, allowing it to be pulled out for maintenance while remaining sealed during operation. This dynamic connection resolves the contradiction between ease of repair and structural complexity.

Inventive Principle:

Principle #15Dynamics

2Reliability

If the turbine diffuser is rigidly connected to the outer casing, then structural stability is maintained, but outer casing deformations affect radial clearance and turbine efficiency

Engineering Contradiction:

Improveturbine efficiencyVSAvoidstructural stability

Core Design Contradiction:

ReliabilityVSStability of the object's composition

Solution Approach 1:

The turbine diffuser is segmented from the gas outlet housing to create an independent mounting system. The diffuser is mounted on the rotor assembly hood rather than the outer housing, creating a separate structural path. This segmentation isolates the diffuser from outer housing deformations, maintaining reliable radial clearance and turbine efficiency while preserving overall structural stability through the new mounting configuration.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The rotor assembly hood acts as an intermediary between the outer housing and the turbine diffuser. By mounting the diffuser on the hood rather than directly on the outer housing, the intermediary isolates the diffuser from deformations in the outer housing, ensuring stable radial clearance and maintaining turbine efficiency while allowing the outer housing structure to remain stable.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Ease of repair

If the turbine diffuser is decoupled from the gas outlet housing, then maintenance is simplified, but leakage flow occurs outside the main flow channel

Engineering Contradiction:

Improvemaintenance easeVSAvoidleakage loss

Core Design Contradiction:

Ease of repairVSLoss of energy

Solution Approach 1:

A throttle seal is introduced as an intermediary element between the turbine diffuser and the gas outlet housing. This seal prevents leakage flow through the new interface created by decoupling the diffuser from the housing, while still allowing the diffuser to be easily removed for maintenance. The throttle seal resolves the contradiction by blocking the leakage path without restricting the movable connection.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

A throttle seal mechanism is used to control and prevent gas leakage through the interface between the decoupled turbine diffuser and gas outlet housing. The throttle seal uses a sealing element that maintains contact with the housing bore to prevent leakage while allowing axial movement of the diffuser for maintenance purposes.

Inventive Principle:

Principle #29Pneumatics and hydraulics

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 reduces disassembly and reassembly times, minimizes the influence of outer housing deformations on turbine efficiency, and reduces flow losses by aerodynamically adapting the diffuser to the operating point through air injection.

Implementation Method 1

a semi-static throttle seal is preferably introduced

Methodology Applied

Scientific EffectThrottle seal:

Implementation Method 2

If air channels are integrated into one or more struts of the hood diffuser, air can be directed through the strut to be blown into the diffuser flow

Methodology Applied

Scientific EffectAir injection:

Data Source

PatentEP2685054B1Diffuser of an exhaust gas turbine

Publication Date: 2020.11.25 ABB (SCHWEIZ) AG

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AI summary

The turbine diffuser (82) of an exhaust gas turbine is attached through the flow channel to the radially inner housing parts (81) that define the flow channel and are part of the rotor assembly. This is achieved via specially aligned and designed struts (83). This allows the rotor, turbine diffuser, and nozzle ring to be removed together as a single assembly without having to dismantle the outer casings.