Vehicle Rotary Compressor Oil Separation With Centrifugal Staging

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Solution Overview

Problem

Rotary compressors face challenges in efficiently separating oil from compressed gas due to the high-speed rotation and turbulent flow, leading to reduced efficiency, wear, and potential contamination of downstream equipment, especially in vehicle applications where space is constrained.

Innovation Solution

A two-stage oil separation system is integrated into the compressor, utilizing a centrifugal separator followed by a flow deceleration separator to leverage oil droplet inertia and coalescence, ensuring effective separation of oil particles from the compressed gas stream.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If a single-stage filtration system is used, then the device complexity is reduced, but the oil separation efficiency deteriorates

Engineering Contradiction:
Improvefiltration system complexityVSAvoidoil separation efficiency
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The filtration system is divided into two distinct stages: a centrifugal separator for initial oil-gas separation and a flow deceleration separator for fine particle removal. This segmentation allows each stage to specialize in removing different sizes of oil particles, achieving high overall separation efficiency while keeping each individual component relatively simple in design

Inventive Principle:
Principle #1Segmentation

2Reliability

If a multi-stage filtration process is used, then the oil separation efficiency is improved, but the device complexity increases

Engineering Contradiction:
Improveoil separation efficiencyVSAvoidfiltration system complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The centrifugal separator and flow deceleration separator are merged into a single integrated separation unit with a unified housing and coordinated internal structure. This merging approach allows the multi-stage filtration process to be implemented while minimizing overall device complexity through shared components and streamlined flow paths

Inventive Principle:
Principle #5Merging (Combining)

3Reliability

If a sufficiently large oil sump housing is used to calm and stabilize the air-oil mixture, then the oil separation efficiency is improved, but the volume occupied increases

Engineering Contradiction:
Improveoil separation efficiencyVSAvoidoil sump housing volume
Core Design Contradiction:
ReliabilityVSVolume of stationary object

Solution Approach 1:

The separation process is segmented into two distinct stages performed in sequence within a compact arrangement. The centrifugal separator handles bulk oil removal, while the flow deceleration separator captures fine particles. This segmentation eliminates the need for a large-volume single-stage housing, achieving effective separation in a reduced space

Inventive Principle:
Principle #1Segmentation

4Productivity

If the compressor operates at high speed, then the productivity is improved, but the oil entrainment in compressed gas increases

Engineering Contradiction:
Improvecompression speedVSAvoidoil entrainment
Core Design Contradiction:
ProductivityVSObject-generated harmful factors

Solution Approach 1:

The centrifugal separator performs preliminary action by removing the majority of oil particles from the compressed gas stream before it enters the flow deceleration separator. This preliminary separation reduces the oil load on the second stage, enabling effective fine particle removal even at high compression speeds without requiring excessive deceleration time

Inventive Principle:
Principle #10Preliminary action

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

The system enhances oil removal efficiency, maintaining compressor performance and longevity by reducing oil contamination and ensuring a cleaner output, suitable for compact vehicle applications.

Implementation Method 1

the first separator comprises a centrifugal separator and is configured to separate oil using centrifugal forces in a first stage

Methodology Applied
Scientific EffectCentrifugal force: Centrifugal Force

Implementation Method 2

the second separator comprises a flow deceleration separator for further separating or capturing oil particles from the compressed gas stream in a second stage

Methodology Applied
Scientific EffectFlow deceleration:

Implementation Method 3

The present invention is based on the basic idea to leverage the mass inertia of the oil droplets and aerosol

Methodology Applied
Scientific EffectInertia: Inertia

Implementation Method 4

as well as the tendency of smaller droplets to combine into larger particles

Methodology Applied
Scientific EffectCoalescence:

Data Source

PatentEP4711619A1Compressor for vehicles with enhanced oil separation efficiency
Publication Date: 2026.03.18 KB INTELLECTUAL PROPERTY GMBH & CO KG
  • EP4711619A1 patent drawingFigure 1
  • EP4711619A1 patent drawingFigure 2
  • EP4711619A1 patent drawingFigure 3

AI summary

Rotary compressor (100), for an air treatment system of a vehicle, comprising a compression cell (2) for producing compressed gas streams, and a separation unit (200) for separating oil from the compressed gas streams, wherein the separation unit is in fluid communication with the compression cell and is configured to separate oil from the compressed gas stream exiting an outlet (9) of the compression cell, and wherein the separation unit comprises a first separator (204), in particular a centrifugal separator, and a second separator (202), in particular a deceleration separator, wherein the second separator is positioned downstream of the first separator in the direction of the compressed gas stream.