Variable Compressor Inlet Geometry for Low-Flow Surge Extension

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Compressors often operate inefficiently at low volume flows due to limitations in their compressor characteristic map, particularly the surge limit, which restricts their usable range and efficiency.

Innovation Solution

A compressor with a variable inlet mechanism using diaphragm elements and an adjusting ring that changes the cross-sectional area of the compressor inlet, allowing for adaptation to different operating ranges and extending the usable compressor characteristic map by displacing the surge limit to lower volume flows, thereby improving efficiency and reducing flow detachment at the compressor wheel hub.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If the compressor operates at low volume flows, then the compressor may no longer achieve sufficient compression efficiency, but reducing the compressor inlet cross-section to accelerate flow may increase flow detachment at the compressor wheel hub

Engineering Contradiction:
Improvecompression efficiencyVSAvoidflow detachment
Core Design Contradiction:
ProductivityVSObject-generated harmful factors

Solution Approach 1:

The patent applies the dynamics principle by implementing a variable inlet cross-section that can be adjusted during operation. The inlet cross-section is divided into multiple adjustable sections (first, second, and third inlet cross-sections) that can be independently controlled to optimize flow characteristics at different operating conditions, preventing flow detachment while maintaining compression efficiency.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent changes the geometric parameter of the inlet cross-section area to control flow acceleration and prevent detachment. By varying the inlet cross-section area according to operating conditions, the system optimizes the balance between flow velocity and flow attachment, resolving the contradiction between compression efficiency and flow detachment.

Inventive Principle:
Principle #35Parameter changes

2Adaptability or versatility

If the compressor inlet cross-section is reduced to accelerate flow and extend the usable characteristic map, then the surge limit is displaced to lower volume flows, but the device complexity increases due to the adjusting mechanism

Engineering Contradiction:
Improveusable compressor characteristic mapVSAvoidadjusting mechanism
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent segments the inlet cross-section into multiple independently adjustable sections (first, second, and third inlet cross-sections). This segmentation allows for fine-grained control of flow characteristics across different operating ranges, extending the usable characteristic map while maintaining manageable system complexity through modular adjustment.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The adjusting mechanism serves multiple functions: it controls flow acceleration, prevents flow detachment, extends the usable characteristic map, and maintains compression efficiency across varying operating conditions. This multi-functionality justifies the added device complexity by providing comprehensive operational adaptability.

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

3Use of energy by moving object

If the inlet cross-section is made variable to improve efficiency across different operating ranges, then fuel consumption and torque build-up are improved, but the manufacturing complexity and cost increase

Engineering Contradiction:
Improvefuel consumptionVSAvoidmanufacturing complexity
Core Design Contradiction:
Use of energy by moving objectVSEase of manufacture

Solution Approach 1:

The dynamic adjustment of the inlet cross-section enables the compressor to operate at optimal efficiency points across different loading conditions, directly improving fuel consumption and torque build-up. The variable geometry allows the system to adapt to changing demands, reducing energy waste and improving overall thermodynamic efficiency despite increased manufacturing complexity.

Inventive Principle:
Principle #15Dynamics

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 enhances compressor efficiency, leading to improved fuel consumption and torque build-up for downstream internal combustion engines by enabling operation across a larger compressor characteristic map and reducing return flows.

Implementation Method 1

The diaphragm elements are rotatably mounted in the compressor housing or in a compressor cover via shafts. The shafts are rotatable about axes parallel to an axis of rotation of the compressor.

Methodology Applied
Scientific EffectRotation:

Implementation Method 2

A lever arm, which is in operative connection with the adjusting ring, is provided per diaphragm element, wherein the lever arm transfers a movement of the adjusting ring to the corresponding diaphragm element.

Methodology Applied
Scientific EffectLever mechanism: Lever

Implementation Method 3

The fresh air is sucked in by a compressor inlet, accelerated by the compressor wheel

Methodology Applied
Scientific EffectCentrifugal force: Centrifugal Force

Data Source

PatentEP3551892B1Compressor with variable compressor inlet
Publication Date: 2023.07.12 BORGWARNER INC
  • EP3551892B1 patent drawingFigure 1
  • EP3551892B1 patent drawingFigure 2A
  • EP3551892B1 patent drawingFigure 2B

AI summary

The invention relates to a compressor with a compressor housing in which a compressor wheel is arranged. The compressor additionally comprises a cartridge which is arranged in the compressor housing in the area of a compressor inlet. The cartridge is designed to variably change the cross section of the compressor inlet.