Capacity Control Valve Force Balancing

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Solution Overview

Problem

Existing capacity control valves for compressors face challenges in stabilizing capacity control when using refrigerants with large pressure fluctuations, leading to increased solenoid size and cost due to the significant influence of control-chamber pressure on the valve body.

Innovation Solution

The capacity control valve design includes a configuration where the pressure receiving area is equal to the difference between the pressure receiving areas of the first and second valve parts, minimizing the influence of control-chamber pressure, allowing for stable capacity control with reduced solenoid size and cost, even with refrigerants like carbon dioxide.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If the passage area of the lead-out passage is increased to maintain fluid flow balance, then the fluid flow tendency is corrected, but the differential pressure caused by control-chamber pressure increases, requiring a larger solenoid

Engineering Contradiction:
Improvefluid flowVSAvoiddifferential pressure
Core Design Contradiction:
Quantity of substanceVSForce

Solution Approach 1:

The patent applies local quality by creating a pressure receiving part with a specific pressure receiving area that is equal to the difference between the pressure receiving areas of the two valve parts. This localized design allows the control-chamber pressure to act differently on each valve part, balancing the forces locally at the valve level rather than requiring a global increase in passage area throughout the system.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent changes the parameter of pressure receiving area by introducing a dedicated pressure receiving part with an area equal to the difference between the two valve parts' pressure receiving areas. This parameter change allows the system to maintain force balance under varying control-chamber pressures without needing to increase the overall passage area, thereby avoiding the need for a larger solenoid.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If a larger solenoid is used to compensate for increased differential pressure, then the valve can maintain proper fluid flow control, but the device size and cost increase

Engineering Contradiction:
Improvevalve control stabilityVSAvoidsolenoid size
Core Design Contradiction:
ReliabilityVSVolume of moving object

Solution Approach 1:

The patent applies local quality by creating a pressure receiving part with a specific pressure receiving area that is equal to the difference between the pressure receiving areas of the two valve parts. This localized design allows the control-chamber pressure to act differently on each valve part, balancing the forces locally at the valve level rather than requiring a global increase in passage area throughout the system.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent changes the parameter of pressure receiving area by introducing a dedicated pressure receiving part with an area equal to the difference between the two valve parts' pressure receiving areas. This parameter change allows the system to maintain force balance under varying control-chamber pressures without needing to increase the overall passage area, thereby avoiding the need for a larger solenoid.

Inventive Principle:
Principle #35Parameter changes

3Stability of the object's composition

If the pressure receiving area is designed to balance the forces on the valve body, then the influence of control-chamber pressure is minimized, but the valve structure becomes more complex

Engineering Contradiction:
Improvevalve body force balanceVSAvoidvalve structure
Core Design Contradiction:
Stability of the object's compositionVSDevice complexity

Solution Approach 1:

The patent merges the pressure receiving function with the existing valve body structure by integrating the pressure receiving part into the valve assembly. Rather than adding a separate complex mechanism, the design combines the pressure receiving area functionality with the valve parts that already exist, thereby achieving force balance without proportionally increasing structural complexity.

Inventive Principle:
Principle #5Merging (Combining)

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 enables stable capacity control and reduces solenoid size and cost while maintaining fluid flow, effectively managing large pressure fluctuations in the control chamber and suction chamber.

Implementation Method 1

a solenoid that operates the valve body, which is formed so that a discharge pressure acts on one side (first valve part side) of the valve body and a suction pressure acts on an opposite side (second valve part side) thereof, with an electromagnetic force so as to perform an open-close operation

Methodology Applied
Scientific EffectElectromagnetic force: Electromagnet

Data Source

PatentEP1895162B9Capacity control valve
Publication Date: 2013.05.29 EAGLE INDS
  • EP1895162B9 patent drawingFigure 1
  • EP1895162B9 patent drawingFigure 2
  • EP1895162B9 patent drawingFigure 3

AI summary

A capacity control valve of the present invention includes a communication path (31) through which a discharge chamber (11) and a control chamber (12) are allowed to communicate with each other; a valve chamber (36) in the middle of the communication path (31); communication paths (32, 31b) through which a suction chamber (13) and the control chamber (12) are allowed to communicate with each other; a valve chamber (36) in the middle of the communication path (32) ; a valve body (40) including a first valve part (41) that opens and closes the communication path (31) and a second valve part (42) that opens and closes the communication path (32), the first and second valve parts being placed in the valve chamber (36) and performing the opening and closing operation in a manner opposite to each other; and a solenoid (60) for moving the valve body (40) . The valve body (40) has a pressure receiving part (44) at its end that is across the second valve part (42) from the first valve part (41), and the pressure receiving part (44) receives a control-chamber pressure. The pressure receiving area (S3) of the pressure receiving part (44) is substantially the same as the difference between the pressure receiving area (S2) of the second valve part (42) and the pressure receiving area (31) of the first valve part. Thereby, the valve is reduced in size, an influence of the pressure in the control chamber is minimized, and stable capacity control with excellent response is enabled.