Variable Displacement Compressor Control Valve for Rapid Startup
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Solution Overview
Problem
Variable displacement type compressors face inefficiencies in starting up due to liquefied refrigerant accumulation and excessive refrigerant release, leading to prolonged displacement increase and reduced operating efficiency.
Innovation Solution
A displacement control mechanism with a second control valve featuring a valve body and spring that adjusts the release passage cross-sectional area, utilizing differential pressures to ensure rapid refrigerant release and optimized operating efficiency, and a check valve to prevent pressure propagation and ensure reliable valve movement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the cross-sectional area of the release passage is made small to improve operating efficiency, then refrigerant gas loss is reduced, but liquefied refrigerant cannot be released rapidly during startup
Solution Approach 1:
The release passage cross-sectional area is made variable rather than fixed. The second control valve dynamically adjusts the opening degree of the release passage based on operating conditions: fully open during startup to rapidly discharge liquefied refrigerant, and throttled during normal operation to minimize refrigerant gas loss. This dynamic adjustment resolves the contradiction between rapid release speed and energy efficiency.
Solution Approach 2:
The patent changes the parameter of release passage cross-sectional area from a constant value to a variable value that adapts to different operational states. By controlling the opening degree of the second control valve, the system optimizes the release passage area parameter for either rapid discharge (startup) or minimal loss (operation), thereby resolving the technical contradiction.
2Loss of time
If the cross-sectional area of the release passage is made large to enable rapid refrigerant release, then startup time is reduced, but operating efficiency deteriorates due to excessive refrigerant gas release
Solution Approach 1:
The release passage cross-sectional area is made variable rather than fixed. The second control valve dynamically adjusts the opening degree of the release passage based on operating conditions: fully open during startup to rapidly discharge liquefied refrigerant, and throttled during normal operation to minimize refrigerant gas loss. This dynamic adjustment resolves the contradiction between rapid release speed and energy efficiency.
3Loss of energy
If a fixed throttle with small cross-sectional area is used in the release passage, then refrigerant gas loss is minimized, but the compressor takes excessive time to reach desired displacement after startup
Solution Approach 1:
The release passage cross-sectional area is made variable rather than fixed. The second control valve dynamically adjusts the opening degree of the release passage based on operating conditions: fully open during startup to rapidly discharge liquefied refrigerant, and throttled during normal operation to minimize refrigerant gas loss. This dynamic adjustment resolves the contradiction between rapid release speed and energy efficiency.
4Adaptability or versatility
If the first control valve is kept open to maintain intermediate displacement operation, then compressor flexibility is improved, but refrigerant gas continuously leaks from the pressure control chamber reducing efficiency
Solution Approach 1:
The patent extracts the refrigerant gas release function from the continuous operation state by introducing a dedicated second control valve. This valve selectively opens the release passage only when necessary (during startup or when pressure control chamber pressure exceeds thresholds), separating the release function from continuous operation. This allows the first control valve to remain closed during normal operation, preventing refrigerant gas loss while maintaining displacement control flexibility when needed.
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 reduces startup time and improves compressor efficiency by ensuring rapid liquefied refrigerant release and minimizing refrigerant flow during operation, enhancing the reliability of valve movement and maintaining efficient compressor performance.
Implementation Method 1
a valve spring for urging the valve body in a direction to open the release passage
Implementation Method 2
pressure in the supply passage downstream the first control valve acts on the valve body in a direction to close the release passage and pressure in the suction-pressure region acts on the valve body in a direction to open the release passage
Data Source
AI summary
A variable displacement type compressor in which a discharge-pressure region, a suction-pressure region and a pressure control chamber are defined, has a tiltable swash plate and a piston reciprocated by the swash plate in the pressure control chamber. The inclination angle of the swash plate and the piston stroke are changed by adjustment of pressure in the pressure control chamber thereby to control the displacement of the compressor. The compressor further comprises a supply passage for supplying refrigerant gas from the discharge-pressure region to the pressure control chamber, a release passage for releasing the refrigerant gas from the pressure control chamber to the suction-pressure region, a first control valve for adjusting a cross-sectional area of the supply passage from the discharge-pressure region to the pressure control chamber and a second control valve for adjusting cross-sectional area of the release passage. The second control valve includes a valve body for opening and closing the release passage whose cross-sectional area is set minimum when the valve body is located at the closed position and a valve spring for urging the valve body in a direction to open the release passage. When the second control valve is closed, pressure in the supply passage downstream the first control valve acts on the valve body in a direction to close the release passage and pressure in the suction-pressure region acts on the valve body in a direction to open the release passage.