Variable Displacement Compressor Control Valve

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Solution Overview

Problem

The existing control valve for variable displacement compressors experiences reduced efficiency due to refrigerant gas leakage from discharge pressure to suction pressure, caused by incomplete blockage, leading to sliding resistance and inaccurate suction pressure maintenance during valve movement.

Innovation Solution

The control valve design incorporates a pressure sensing section where discharge pressure applies an urging force to the movement member, with a solenoid section providing additional force, and a sealed chamber formed by the contact between the expanding and contracting member and the movement member to block communication between discharge and suction pressures, eliminating sliding resistance and ensuring accurate flow rate adjustment.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a ring seal is used in the connecting rod to block communication between pressure sensing chamber and discharge pressure port, then refrigerant gas leakage is prevented, but sliding resistance increases causing inaccurate valve opening position and incorrect suction pressure maintenance

Engineering Contradiction:
Improveblockage efficiencyVSAvoidsliding resistance
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The invention extracts and eliminates the ring seal component from the connecting rod structure. By removing this sealing element, the source of sliding resistance is eliminated while the blockage function is achieved through the geometric configuration of the connecting rod itself, which naturally blocks the communication path between the pressure sensing chamber and discharge pressure port.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The invention introduces a sealed chamber as an intermediary space between the suction pressure chamber and discharge pressure port. This sealed chamber acts as a mediator that prevents direct communication between high and low pressure zones without requiring sliding seals, thereby eliminating the trade-off between sealing effectiveness and sliding resistance.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Object-affected harmful factors

If the connecting rod allows communication between discharge pressure and suction pressure, then sliding resistance is reduced, but refrigerant gas leakage occurs reducing compressor efficiency

Engineering Contradiction:
Improvesliding resistanceVSAvoidcompressor efficiency
Core Design Contradiction:
Object-affected harmful factorsVSLoss of energy

Solution Approach 1:

The invention converts the potential harm of refrigerant gas leakage into a benefit by using the pressure differential itself to maintain the blockage. The connecting rod is positioned such that pressure differences between discharge and suction sides actually enhance the sealing effect rather than overcome it, eliminating the need for additional sealing mechanisms that would create sliding resistance.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

3Measurement precision

If discharge pressure is introduced to pressure sensing section, then accurate flow rate control is achieved, but refrigerant gas leakage from discharge to suction pressure reduces efficiency

Engineering Contradiction:
Improveflow rate control accuracyVSAvoidcompressor efficiency
Core Design Contradiction:
Measurement precisionVSLoss of energy

Solution Approach 1:

The invention segments the pressure sensing system into distinct isolated chambers. The pressure sensing chamber that receives discharge pressure is completely separated from the suction pressure chamber through the connecting rod structure and sealed chamber configuration. This segmentation allows accurate flow rate control based on discharge pressure while preventing energy loss from refrigerant gas leakage between pressure zones.

Inventive Principle:
Principle #1Segmentation

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 design stabilizes and accurately adjusts the air flow rate by eliminating sliding resistance and maintaining the correct suction pressure, preventing valve closure due to increased discharge pressure, thus enhancing the compressor's efficiency and control precision.

Implementation Method 1

suction pressure Ps acts on the pressure sensing chamber 16. The bellows assembly 4 has a bellows 19 that is retained at both ends by holders 17, 18 so as to be able to expand and contract

Methodology Applied
Scientific EffectPressure: Pressure Increase

Implementation Method 2

a spring 20 extends between the holders, and a connecting rod 21 in contact with and connected to both members is disposed between the holder 18 and the left end 10a of the valve rod 10

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 3

magnetic force is generated by applying an electrical current to a coil 6, a movable iron core 7 is moved against a spring 8 toward a fixed iron core 9 disposed to the left

Methodology Applied
Scientific EffectMagnetic force: Magnetism

Implementation Method 4

a movable iron core 7 is moved against a spring 8

Methodology Applied
Scientific EffectSpring force: Spring

Implementation Method 5

the valve section 3 is configured so as to be capable of adjusting the rate of flow of discharged refrigerant gas into the inside of the compressor on the basis of the degree of opening of a valve element 13 formed at an end of the valve rod 10 with respect to a valve seat 14

Methodology Applied
Scientific EffectFlow rate control:

Data Source

PatentEP2000670B1Control valve for variable displacement compressor
Publication Date: 2018.07.25 EAGLE INDS
  • EP2000670B1 patent drawingFigure 1~2
  • EP2000670B1 patent drawingFigure 3~4
  • EP2000670B1 patent drawingFigure 5

AI summary

[PROBLEMS] A control valve for a variable displacement compressor, where sliding resistance by movement of a valve is reduced as much as possible to stably and accurately regulate the rate of air flow, enabling a suction pressure corresponding to solenoid thrust to be maintained. [MEANS FOR SOLVING PROBLEMS] The discharge pressure Pd of the compressor introduced into a pressure sensing section (40) applies urging force to a movement member (50), and a solenoid section (36) applies, in cooperation with the urging force, urging force to the movement member (50) depending on an input signal. The degree of opening of a valve body (56) provided at the movement member (50) is set according to the position of the movement member (50) to regulate the rate of air flow in a communication path for interconnecting a discharge pressure region of the compressor and a compressor inner chamber. The suction pressure Ps of the compressor is introduced into a control valve to apply urging force to the movement member (50), and communication between fluid having the discharge pressure Pd introduced into the pressure sensing section (40) and fluid having the suction pressure Ps introduced into the control valve is shut off.