Capacity Control Valve with Startup Pressure Equalization
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Solution Overview
Problem
The existing capacity control valves for variable displacement compressors suffer from poor controllability and operation efficiency due to refrigerant flow from the control port to the suction port during continuous operation, affecting the compressor's performance.
Innovation Solution
A capacity control valve design with a primary valve and a CS valve that allows communication between the control and suction ports only during startup and maximum energized states, maintaining equal pressures and preventing refrigerant flow during normal operation, utilizing a solenoid-driven rod and an urging member for precise control and movement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If an auxiliary communication path is formed to communicate the control port and suction port, then the responsiveness of the variable displacement compressor is improved at startup, but the controllability of the control chamber pressure deteriorates during continuous operation
Solution Approach 1:
The capacity control valve is segmented into two separate valves: a primary valve for controlling the discharge port and control port communication, and a CS valve for controlling the control port and suction port communication. This segmentation allows independent control of each function, enabling the system to achieve both rapid pressure equalization at startup and stable pressure control during continuous operation.
Solution Approach 2:
The CS valve is designed to dynamically open or close the auxiliary communication path between the control port and suction port based on operational conditions. During startup, the CS valve opens to rapidly equalize pressures and improve responsiveness. During continuous operation, the CS valve closes to prevent refrigerant leakage and maintain controllability, thus adapting the system behavior to different operational states.
2Speed
If the auxiliary communication path remains open during continuous operation, then the startup responsiveness is maintained, but the operation efficiency of the variable displacement compressor deteriorates
Solution Approach 1:
The CS valve operates periodically based on the operational state of the compressor. It opens during startup or maximum capacity conditions to provide rapid pressure equalization, then closes during normal continuous operation to prevent refrigerant leakage. This periodic opening and closing allows the system to enjoy the benefits of fast startup responsiveness only when needed, while maintaining high operation efficiency during continuous running.
3Device complexity
If the primary valve body and rod are fixed together, then the valve structure is simplified, but the ability to independently control the primary valve and CS valve is lost
Solution Approach 1:
The valve assembly is divided into separate components: the primary valve body for controlling the discharge port, the rod for actuating both valves, and the CS valve for controlling the auxiliary communication path. This segmentation enables independent control of each valve function while still using a unified rod actuation mechanism, balancing structural simplicity with operational flexibility.
Solution Approach 2:
The rod serves multiple functions: it actuates the primary valve to control the main discharge flow and simultaneously actuates the CS valve to control the auxiliary communication path. This multi-functionality allows a single actuator to control both valves, simplifying the overall actuation system while maintaining independent valve control capability through the separate valve bodies and seating 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 design enhances the discharge and operation efficiency of the variable displacement compressor by maintaining control and suction pressures equal during startup and ensuring efficient refrigerant discharge, thereby improving the compressor's responsiveness and controllability.
Implementation Method 1
a capacity control valve including a valve housing provided with a discharge port allowing a discharge fluid of a discharge pressure to pass therethrough, a suction port allowing a suction fluid of a suction pressure to pass therethrough, and a control port allowing a control fluid of a control pressure to pass therethrough, a rod driven by a solenoid
Implementation Method 2
an urging member configured to urge the primary valve body and the rod in opposite directions
Data Source
Figure 1
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AI summary
To provide a capacity control valve having good operation efficiency while having a fluid discharge function at startup. A capacity control valve V includes a valve housing 10 provided with a discharge port 12 allowing a discharge fluid of a discharge pressure Pd to pass therethrough, a suction port 15 allowing a suction fluid of a suction pressure Ps to pass therethrough, and control ports 13 and 14 allowing a control fluid of a control pressure Pc to pass therethrough, rods 52 and 54 driven by a solenoid 80, and a primary valve 50 including a primary valve seat 10a and a primary valve body 51 and opens and closes a communication between the discharge port 12 and the control port 13 by the movement of the rods 52 and 54. The capacity control valve V further includes a CS valve 56 which opens and closes a communication between the control fluid and the suction fluid by the movement of the rods 52 and 54 and an urging member 91 configured to urge the primary valve body 51 and the rods 52 and 54 in opposite directions and the primary valve body 51 and the rods 52 and 54 are disposed so as to be relatively movable in an axial direction.