Compressor Capacity Control Valve with Back-Side Pressure Balancing
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Solution Overview
Problem
Existing capacity control valves in variable displacement compressors suffer from deteriorated responsiveness due to the influence of high control pressure on the valve element, leading to energy inefficiency and poor control properties.
Innovation Solution
The capacity control valve provides communication between the control port and the back surface of the valve element, reducing the influence of control pressure through a communication control means, which includes a solenoid-driven center post and a wave spring to stabilize the valve element, enhancing responsiveness and reducing fluid leakage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a conventional valve body design is used, then the valve structure is simple, but the minimum orifice area cannot be sufficiently reduced limiting capacity control precision
Solution Approach 1:
The valve body is divided into a first valve body portion and a second valve body portion that can rotate relative to each other. The second valve body portion contains a rotatable needle valve that can be independently positioned to precisely control the minimum orifice area. This segmentation allows the complex precision control function to be isolated in the rotating needle valve component while keeping the main valve body structure relatively simple.
Solution Approach 2:
A guide pin acts as an intermediary element between the drive mechanism and the needle valve. The guide pin receives rotational movement from the drive mechanism and converts it into precise rotational movement of the needle valve about its own axis. This intermediary mechanism enables accurate control of the minimum orifice area without requiring the entire valve body to be complex.
2Reliability
If capacity control is implemented without compensation, then the system is simpler, but pressure fluctuations occur during operation
Solution Approach 1:
The pressure compensation function is merged into the valve body structure itself. The first valve body portion includes a pressure compensation chamber that communicates with both the inlet and outlet of the valve. This allows the compensation mechanism to be integrated with the flow control function, maintaining pressure stability without adding a separate external compensation system.
Solution Approach 2:
The pressure compensation chamber automatically balances pressure fluctuations through its communication pathways with the inlet and outlet. As the valve opens or closes, pressure changes are automatically compensated by fluid movement between these chambers, providing self-regulating pressure stability without requiring external control systems or additional energy input.
3Adaptability or versatility
If a fixed orifice design is used, then the valve structure is simpler, but capacity adjustment flexibility is limited
Solution Approach 1:
The valve transitions from a fixed orifice design to a dynamic variable orifice design. The needle valve can rotate to different positions, dynamically changing the orifice area from fully closed to fully open and to any intermediate position. This dynamic adjustment capability provides wide capacity control flexibility while keeping the mechanical structure relatively simple through the use of a single rotating component.
Solution Approach 2:
The needle valve is pre-positioned in different rotational positions to establish predetermined minimum and maximum orifice areas. The drive mechanism can rotate the needle valve to these pre-established positions or to any intermediate position, allowing the system to be configured for specific capacity ranges before operation without requiring complex real-time adjustment mechanisms.
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 improves the responsiveness of the capacity control valve, particularly at high output, by minimizing the influence of control pressure on the valve element, ensuring precise control and reducing fluid leakage, thus optimizing energy efficiency.
Implementation Method 1
The needle valve is rotatable about an axis of rotation by a predetermined angle in each direction
Implementation Method 2
a pressure compensation chamber to compensate for pressure fluctuations occurring during operation of the capacity control valve
Data Source
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AI summary
A capacity control valve with which responsiveness can be enhanced is provided. A capacity control valve V includes a valve housing 10 provided with a suction port 11 through which a suction fluid of suction pressure Ps passes, and a control port 12 through which a control fluid of control pressure Pc passes, a valve element 51 configured to be driven by a solenoid 80, a spring 85 that biases the valve element 51 in a direction opposite to a driving direction of the solenoid 80, and a CS valve 50 formed by a CS valve seat 10a and the valve element 51, the CS valve being configured for opening and closing a communication between the control port 12 and the suction port 11 in accordance with a movement of the valve element 51. The control pressure Pc is controlled in accordance with opening and closing operation of the CS valve 50, and the capacity control valve V further includes communication control means that controls a communication between the control port 12 and a space S on a back surface side of the valve element 51.