Capacity Control Valve Layout for Stable Compressor Pressure Control
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Solution Overview
Problem
Existing capacity control valves in variable displacement compressors are prone to malfunction due to sudden increases in control pressure, leading to unintended opening of the valve element and potential excessive contraction of the bellows, which affects the control fluid flow and cooling ability of air conditioning systems.
Innovation Solution
A capacity control valve design featuring a valve element that receives a closing force from the control fluid, combined with a pressure drive portion and a spring for stable operation, and a separate suction port to isolate pressure drive and main valve spaces, preventing unintended opening and ensuring precise control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the control pressure is applied in the opening direction of the valve element, then the valve can be opened by control pressure, but the valve element may open due to malfunction when control pressure becomes instantaneously high
Solution Approach 1:
The patent inverts the conventional control mechanism by applying control pressure in the closing direction rather than the opening direction. The valve element is configured to open in response to suction pressure while control pressure acts to close it, preventing unintended opening due to pressure fluctuations or vibrations.
Solution Approach 2:
The patent employs a counterbalancing force mechanism where suction pressure provides the opening force and control pressure provides the closing force. This counterweight approach ensures that the valve element remains stable and only opens when suction pressure exceeds control pressure, preventing malfunction from transient pressure increases.
2Adaptability or versatility
If the valve element opens due to malfunction, then control fluid may flow into the suction chamber, but the bellows may be excessively contracted
Solution Approach 1:
The patent inverts the pressure control mechanism to prevent bellows damage. By applying control pressure to close the valve rather than open it, the system prevents uncontrolled opening that would cause excessive suction pressure to act on the bellows, thereby protecting the bellows from excessive contraction and potential failure.
3Speed
If the valve element receives force only in the opening direction, then the valve can respond to suction pressure, but the valve may open unintentionally due to control pressure increases
Solution Approach 1:
The patent implements a counterweight force system where suction pressure provides the opening force and control pressure provides the closing force. This dual-force mechanism maintains rapid valve response to suction pressure changes while preventing unintended opening from control pressure fluctuations, achieving both speed and precision.
Solution Approach 2:
The patent utilizes parameter changes in pressure differential control. The valve element responds to changes in the balance between suction pressure and control pressure, allowing rapid response when suction pressure increases while maintaining stability when control pressure fluctuates, thus achieving both fast response and precise control.
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 ensures stable operation of the main valve, preventing malfunctions and maintaining precise control over the compressor's discharge amount, thereby enhancing the cooling ability of air conditioning systems by preventing unintended opening due to increased control pressure.
Implementation Method 1
a pressure drive portion that receives a force in a contracting direction from the suction fluid
Implementation Method 2
the valve element is arranged to receive a force in a valve closing direction of the main valve from the control fluid
Data Source
AI summary
A capacity control valve in which control precision is high is provided. A capacity control valve V includes a valve housing provided with a suction port through which a suction fluid of suction pressure Ps passes, and a control port through which a control fluid of control pressure Pc passes, a pressure drive portion that receives a force in the contracting direction from the suction fluid, and a main valve formed by a valve element that receives a force in the valve opening direction from the pressure drive portion, and a valve seat with and from which the valve element is brought into contact and separated. The valve element is arranged to receive a force in the closing direction from the control fluid.