Capacity Control Valve Pressure Balancing for Faster CS Valve Response
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Solution Overview
Problem
The responsiveness of capacity control valves in variable displacement compressors is deteriorated due to the large pressure receiving area for control pressure, leading to poor energy efficiency and fluid leakage when the CS valve is opened, as the control pressure biases the valve element in the valve opening direction.
Innovation Solution
A capacity control valve with a communication control means that allows control fluid to be supplied to the back surface side of the valve element, reducing the influence of control pressure and enhancing responsiveness, by providing communication between the control port and the back surface side of the valve element, which can communicate with the suction port via a throttle or guide hole, and utilizing electromagnetic force to control fluid communication.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If the control pressure Pc is applied to a large pressure receiving area on the valve element, then the valve element is biased in the valve opening direction, but the responsiveness of the capacity control valve is deteriorated
Solution Approach 1:
The pressure receiving surface of the valve element is divided into two distinct areas: a first pressure receiving area that receives control pressure Pc to bias the valve element in the opening direction, and a second pressure receiving area that receives suction pressure Ps to bias the valve element in the closing direction. This segmentation allows independent control of the opposing forces acting on the valve element, enabling precise responsiveness control.
Solution Approach 2:
Instead of applying only control pressure Pc to the valve element, the invention applies suction pressure Ps to the second pressure receiving area in the opposite direction. This creates a balanced force system where the valve element responds more quickly to control signals by having a predetermined closing bias force that counteracts the opening bias force.
2Ease of operation
If the control pressure Pc is higher than the suction pressure Ps and applied to bias the valve element in the valve opening direction, then the valve element opens, but control fluid leaks round to the back surface side of the valve element and energy efficiency is poor
Solution Approach 1:
The invention creates a pressure balance condition where the force from control pressure Pc on the first pressure receiving area is counterbalanced by the force from suction pressure Ps on the second pressure receiving area. This equipotential approach prevents excessive pressure differential that would cause fluid to leak round to the back surface side of the valve element, thereby improving energy efficiency.
Solution Approach 2:
The invention changes the pressure parameter applied to the valve element by introducing suction pressure Ps to the second pressure receiving area, rather than relying solely on control pressure Pc. This parameter change creates a more efficient pressure distribution that prevents fluid leakage while maintaining valve opening capability.
3Reliability
If the suction pressure Ps influence is cancelled by supplying suction fluid to the back surface side of the valve element, then the control property of the CS valve is excellent, but the control pressure Pc biases the valve element in the valve opening direction and responsiveness is deteriorated
Solution Approach 1:
The pressure receiving surface is segmented into two functional zones: the first pressure receiving area for control pressure Pc that ensures reliable valve opening, and the second pressure receiving area for suction pressure Ps that provides responsive closing action. This segmentation allows both control reliability and responsiveness to be optimized simultaneously.
Solution Approach 2:
Different local areas of the valve element are assigned different pressure characteristics: the first pressure receiving area is optimized for receiving control pressure to ensure reliable opening, while the second pressure receiving area is optimized for receiving suction pressure to enhance responsiveness. This local quality differentiation resolves the contradiction between control property and responsiveness.
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 enhances the responsiveness of the capacity control valve during high output operations of the variable displacement compressor, reduces fluid leakage, and maintains precise control over the valve opening degree by managing pressure differences effectively.
Implementation Method 1
a valve element configured to be driven by a solenoid
Implementation Method 2
a spring that biases the valve element in a direction opposite to a driving direction of the solenoid
Implementation Method 3
the control pressure is controlled in accordance with opening and closing operation of the CS valve
Data Source
AI summary
A capacity control valve 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 valve element configured to be driven by a solenoid, a spring that biases the valve element in a direction opposite to a driving direction of the solenoid, and a CS valve formed by a CS valve seat and the valve element, the CS valve being configured for opening and closing a communication between the control port and the suction port in accordance with a movement of the valve element. The capacity control valve further includes communication controller that controls a communication between the control port and a space on a back surface side of the valve element.