Compressor Sliding Alloy and Oil Additives for HFO Corrosion

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Solution Overview

Problem

Refrigerants containing hydrofluoroolefins are unstable to moisture and oxygen, leading to impurity production and corrosion of compressor sliding portions, particularly in aluminum alloys, which can be exacerbated by high silicon content in these alloys.

Innovation Solution

A compressor using a refrigerant with hydrofluoroolefin and a refrigeration oil containing a polyol ester or polyvinyl ether, with an aluminum alloy sliding portion containing 5-25% silicon, and additives like acid scavengers, oxygen scavengers, and extreme pressure additives to inhibit corrosion.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If a refrigerant containing hydrofluoroolefin is used, then ozone layer depletion is reduced, but the refrigerant deteriorates and produces impurities that corrode compressor sliding portions

Engineering Contradiction:
Improveozone layer depletionVSAvoidcompressor sliding portion corrosion
Core Design Contradiction:
Object-affected harmful factorsVSReliability

Solution Approach 1:

The patent introduces an aluminum alloy sliding portion with 5-25 wt% silicon content as an intermediary material that resists corrosion from hydrofluoroolefin deterioration products. The silicon-containing aluminum alloy acts as a protective barrier between the corrosive refrigerant impurities and the compressor components, preventing direct chemical attack while allowing the environmentally friendly refrigerant to be used.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent changes the material parameter of the sliding portion by specifying precise silicon content (5-25 wt%) in the aluminum alloy. This parameter modification fundamentally alters the material's chemical resistance properties, enabling it to withstand the corrosive environment created by hydrofluoroolefin refrigerant deterioration without compromising the refrigerant's environmental benefits.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If the silicon content in aluminum alloy sliding portions is increased to inhibit corrosion, then corrosion resistance improves, but material cost and manufacturing complexity increase

Engineering Contradiction:
Improvecorrosion resistanceVSAvoidmaterial cost and manufacturing complexity
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent establishes a specific silicon content range (5-25 wt%) in the aluminum alloy sliding portion that optimizes the balance between corrosion resistance and manufacturability. This parameter specification ensures sufficient protection against hydrofluoroolefin-induced corrosion while avoiding the need for expensive high-silicon alloys or complex manufacturing processes, making the solution economically viable.

Inventive Principle:
Principle #35Parameter changes

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 solution effectively captures acids and inhibits corrosion, maintaining compressor performance and reducing wear, while using cost-effective aluminum alloys.

Implementation Method 1

The refrigeration oil contains an acid scavenger or an oxygen scavenger... This inhibits corrosion of the sliding portion of the compressor due to deterioration of the refrigerant containing a hydrofluoroolefin

Methodology Applied
Scientific EffectAcid scavenging: Absorption (physical)

Implementation Method 2

The refrigeration oil contains an acid scavenger or an oxygen scavenger... This inhibits corrosion of the sliding portion of the compressor due to deterioration of the refrigerant containing a hydrofluoroolefin

Methodology Applied
Scientific EffectOxygen scavenging: Absorption (physical)

Implementation Method 3

A compressor of a second aspect is the compressor of the first aspect, in which the refrigeration oil contains an extreme pressure additive

Methodology Applied
Scientific EffectExtreme pressure lubrication: Lubrication

Implementation Method 4

A compressor of a third aspect is the compressor of the first or second aspect, in which the refrigeration oil contains an antioxidant

Methodology Applied
Scientific EffectOxidation prevention: Oxidation

Data Source

PatentEP4656701A1Compressor and refrigeration cycle device
Publication Date: 2025.12.03 DAIKIN INDUSTRIES LTD
  • EP4656701A1 patent drawingFigure 1
  • EP4656701A1 patent drawingFigure 2
  • EP4656701A1 patent drawingFigure 3

AI summary

An object of the present disclosure is to inhibit corrosion of a compressor in a refrigeration cycle apparatus in which a refrigerant containing a hydrofluoroolefin is used. A compressor (30) is a compressor (30) for a refrigeration cycle apparatus (20) that performs a refrigeration cycle using a refrigerant containing a hydrofluoroolefin and a refrigeration oil containing a polyol ester or a polyvinyl ether. The compressor (30) includes a sliding portion (79s). The sliding portion (79s) is formed of an aluminum alloy containing from 5 wt% to 25 wt% of silicon. The refrigeration oil contains an acid scavenger or an oxygen scavenger and satisfies the following relational formula: total content (wt%) of acid scavenger and oxygen scavenger in refrigeration oil ≥ (2.3 + 2.6 × (hydrofluoroolefin content (wt%) in refrigerant) - 1.6 × (silicon content (wt%) in sliding portion)) / 100