Centrifugal Compressor Axial Gap Adjustment Mechanism

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Solution Overview

Problem

Radial compressors in exhaust gas turbochargers face performance reduction due to excessively wide gaps between the compressor wheel and housing, leading to frictional forces and reduced conveying capacity, which existing technologies fail to effectively address.

Innovation Solution

The implementation of an axially displaceable housing insert, a rotary disk, and a piston system that allows for adjustable gap width between the compressor wheel and housing, enabling manual and automatic adjustment of the gap, along with a spring for damping and force scaling, and latching means for reliable positioning, to optimize compressor efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the gap between the compressor wheel and compressor housing is made wide to ensure friction-free rotation, then reliability is improved, but productivity deteriorates due to reduced conveying capacity

Engineering Contradiction:
Improvefriction-free rotationVSAvoidconveying capacity
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The housing insert is made axially displaceable, allowing the gap width between the compressor wheel and housing to be dynamically adjusted based on operating conditions. This enables optimization between friction-free operation and conveying capacity by adapting the gap width to different operational requirements.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The gap width parameter is made variable through the displaceable housing insert mechanism. By changing the gap width parameter, the system can optimize performance across different operating states, preventing both excessive friction and excessive leakage.

Inventive Principle:
Principle #35Parameter changes

2Productivity

If the gap between the compressor wheel and compressor housing is reduced to improve conveying capacity, then productivity is improved, but reliability deteriorates due to increased frictional forces

Engineering Contradiction:
Improveconveying capacityVSAvoidfriction-free rotation
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The adjustable gap mechanism allows the system to dynamically reduce the gap width when high conveying capacity is needed, while maintaining reliability by preventing excessive friction through controlled adjustment limits and appropriate gap selection.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The gap width parameter is optimized for different operating conditions. By changing this parameter, the system achieves improved conveying capacity while maintaining reliability through controlled parameter selection.

Inventive Principle:
Principle #35Parameter changes

3Ease of manufacture

If the gap width is fixed during manufacturing to simplify production, then ease of manufacture is improved, but adaptability deteriorates due to inability to compensate for manufacturing tolerances

Engineering Contradiction:
Improveproduction simplicityVSAvoidtolerance compensation
Core Design Contradiction:
Ease of manufactureVSAdaptability or versatility

Solution Approach 1:

The housing is segmented into a fixed outer housing and a displaceable inner housing insert. This segmentation allows the insert to be adjusted independently to compensate for manufacturing tolerances, while the overall structure remains relatively simple to manufacture.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The housing insert is pre-configured with adjustment capability built into the manufacturing process. This preliminary action of creating an adjustable structure allows subsequent field adjustment to compensate for tolerances without requiring complex rework.

Inventive Principle:
Principle #10Preliminary action

4Adaptability or versatility

If an adjustment mechanism is added to make the housing insert displaceable, then adaptability is improved, but device complexity increases

Engineering Contradiction:
Improvegap adjustment capabilityVSAvoidhousing structure
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The housing insert is designed to be axially displaceable through a relatively simple mechanism, adding dynamic adjustment capability without creating excessive complexity. The displacement mechanism allows gap adjustment while maintaining structural simplicity.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The displaceable housing insert serves multiple functions: adjusting the gap width, compensating for manufacturing tolerances, and adapting to different operating conditions. This multi-functionality justifies the added complexity by providing comprehensive adaptability.

Inventive Principle:
Principle #6Universality (Multi-functionality)

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 optimal gap adjustment, compensating for manufacturing tolerances and improving compressor efficiency while maintaining production costs, ensuring friction-free operation and enhanced performance by adapting to varying operating states.

Implementation Method 1

a spring, which is arranged between the piston and the housing insert in order to press the piston against the rotary disk

Methodology Applied
Scientific EffectSpring: Spring

Implementation Method 2

the spring also represents a damping means, which dampens vibrations that occur during compressor operation

Methodology Applied
Scientific EffectDamping: Damping

Implementation Method 3

the rotary disc transmits a force to the housing insert via the piston

Methodology Applied
Scientific EffectMechanical Force: Mechanical Force

Implementation Method 4

a radial compressor for an exhaust gas turbocharger... a compressor wheel, by means of which the respective gas can be conveyed and compressed

Methodology Applied
Scientific EffectCentrifugal Force: Centrifugal Force

Data Source

PatentEP3056690B1Centrifugal compressor, exhaust gas turbocharger and corresponding method for operating a centrifugal compressor
Publication Date: 2019.08.21 ROBERT BOSCH GMBH
  • EP3056690B1 patent drawingFigure 1
  • EP3056690B1 patent drawingFigure 2
  • EP3056690B1 patent drawingFigure 3a~3b

AI summary

The invention provides a radial compressor for an exhaust gas turbocharger, in particular for an internal combustion engine, as well as an exhaust gas turbocharger with such a radial compressor. The invention further relates to a method for operating such a radial compressor.The radial compressor for an exhaust gas turbocharger comprises the following: a housing with an axial inlet channel and a radial outlet channel, which at least partially surrounds a compressor chamber, wherein a recess is provided in the housing on the inlet channel side, a compressor wheel arranged in the compressor chamber for conveying and compressing a gas from the inlet channel to the outlet channel, means for adapting the inner housing contour, comprising: an axially displaceable housing insert, which is arranged in the compressor chamber in an area between the housing and the compressor wheel, a rotary disk, which is rotatably mounted around the inlet channel by means of a pin engaging in the recess, a piston, which is arranged between the rotary disk and the housing insert.