Scroll Compressor Oil Supply Timing to Reduce Leakage

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Solution Overview

Problem

In scroll compressors, especially the bottom-compression type, there is a challenge in preventing refrigerant from flowing back from high-pressure to low-pressure compression chambers due to pressure differences, leading to compression loss and leakage, particularly during low-pressure ratio operations.

Innovation Solution

The solution involves designing the scroll compressor with non-overlapping crank angle ranges for the first and second compression chamber oil supply holes, ensuring that the oil supply holes do not communicate with both compression chambers simultaneously, thereby minimizing the section where pressure differences can cause refrigerant backflow. This is achieved by positioning the outlets of the oil supply holes such that the first crank angle range and the second crank angle range do not overlap, with specific intervals and positions that optimize oil supply without interrupting the compression process.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If separate oil supply holes are provided for first and second compression chambers, then smooth oil supply to both chambers can be expected, but refrigerant may flow back from high-pressure to low-pressure chamber causing compression loss

Engineering Contradiction:
Improveoil supply smoothnessVSAvoidcompression loss
Core Design Contradiction:
Ease of operationVSLoss of energy

Solution Approach 1:

The patent divides the oil supply system into separate first and second oil supply holes that individually supply oil to the first and second compression chambers. This segmentation allows independent control of oil supply timing to each chamber, preventing simultaneous opening that would cause refrigerant backflow while maintaining smooth oil supply to both chambers throughout the compression cycle.

Inventive Principle:
Principle #1Segmentation

2Reliability

If oil supply holes are positioned to communicate with compression chambers at all times, then continuous oil supply is ensured, but refrigerant leakage between chambers occurs during low-pressure ratio operation

Engineering Contradiction:
Improvecontinuous oil supplyVSAvoidrefrigerant leakage
Core Design Contradiction:
ReliabilityVSLoss of energy

Solution Approach 1:

The patent employs dynamic timing control of the oil supply holes based on the compression cycle phase. The first oil supply hole communicates with the first compression chamber during its compression phase, while the second oil supply hole communicates with the second compression chamber during its compression phase. This dynamic, phase-synchronized operation ensures continuous oil supply to both chambers while preventing refrigerant leakage by avoiding simultaneous communication with both chambers.

Inventive Principle:
Principle #15Dynamics

3Duration of action of moving object

If crank angle ranges for oil supply overlap, then uninterrupted oil supply is achieved, but pressure difference causes refrigerant backflow and compression loss

Engineering Contradiction:
Improveuninterrupted oil supplyVSAvoidcompression loss
Core Design Contradiction:
Duration of action of moving objectVSLoss of energy

Solution Approach 1:

The patent implements periodic, alternating operation of the first and second oil supply holes synchronized with the compression cycle. Each oil supply hole operates during its respective compression chamber's compression phase and remains closed during the other chamber's phase. This periodic, non-overlapping action pattern ensures that oil supply is maintained throughout the cycle while preventing refrigerant backflow caused by pressure differences between chambers.

Inventive Principle:
Principle #19Periodic 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

This configuration effectively reduces friction loss and prevents refrigerant backflow between compression chambers, enhancing compression efficiency and reliability even during low-pressure ratio operations.

Implementation Method 1

The oil supply portion may supply oil using an oil pump or using differential pressure

Methodology Applied
Scientific EffectDifferential pressure: Pressure Gradient

Implementation Method 2

a compression chamber including a suction chamber, an intermediate pressure chamber, and a discharge chamber between both scrolls while the plurality of scrolls is an engaged state

Methodology Applied
Scientific EffectCompression: Compression

Data Source

PatentEP3957854B1Scroll compressor
Publication Date: 2024.10.23 LG ELECTRONICS INC
  • EP3957854B1 patent drawingFigure 1
  • EP3957854B1 patent drawingFigure 2
  • EP3957854B1 patent drawingFigure 3

AI summary

A scroll compressor according to the present disclosure includes a fixed scroll, an orbiting scroll forming first and compression chambers with the fixed scroll, first and second compression chamber oil supply holes formed through the orbiting scroll to communicate with the first compression chamber and the second compression chamber, respectively, wherein when a section in which the first compression chamber oil supply hole is opened toward the first compression chamber is a first crank angle range and a section in which the second compression chamber oil supply hole is opened toward the second compression chamber, a non-overlap range between the first crank angle range and the second crank angle range may be longer than an overlap range between the first crank angle range and the second crank angle range, so as to prevent communication between the first and second compression chambers, thereby suppressing leakage between the compression chambers.