Displacement Control Valve Gap Passage Design
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Solution Overview
Problem
Variable displacement compressors experience prolonged startup times due to liquefied refrigerant accumulation in the control pressure chamber, leading to increased pressure and delayed displacement recovery, as existing displacement control valves face high flow resistance and inefficiencies in releasing refrigerant from the control pressure chamber to the suction pressure region.
Innovation Solution
The displacement control valve design incorporates a pressure-sensitive mechanism with a bellows and gap passages that reduce flow resistance by enlarging the cross-sectional area, allowing liquefied refrigerant to be readily released from the control pressure chamber to the suction chamber, facilitated by a drive rod structure with flat surfaces and gap passages that minimize resistance and enhance the coupling between the drive rod and valve body.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the displacement control valve keeps the cross-sectional area of the regulation passage in a small state, then the pressure control precision is improved, but the liquefied refrigerant cannot be readily released from the control pressure chamber
Solution Approach 1:
The relief passage is divided into two functional sections: a first relief passage with a small cross-sectional area for precise pressure control during normal operation, and a second relief passage with a large cross-sectional area for rapid refrigerant release when needed. This segmentation allows the system to achieve both precise pressure control and rapid refrigerant evacuation by selectively opening different passage sections.
2Volume of moving object
If the linear shaft passage and linear terminal portion extend perpendicular to each other in the drive rod, then the structural compactness is improved, but the flow resistance increases
Solution Approach 1:
The passage structure transitions from a two-dimensional perpendicular arrangement to a three-dimensional optimized flow path. The first relief passage extends in a first direction from the control pressure chamber, while the second relief passage extends in a second direction perpendicular to the first direction, creating a multi-dimensional flow path that reduces flow resistance while maintaining compact valve structure.
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 significantly reduces the time required for compressor displacement to increase after activation by efficiently releasing liquefied refrigerant, ensuring rapid recovery of the swash plate inclination angle from minimum to maximum, thereby improving startup efficiency and reducing flow resistance.
Implementation Method 1
a bellows, an electromagnetic solenoid, and a valve body driven by the electromagnetic solenoid
Implementation Method 2
an electromagnetic solenoid, and a valve body driven by the electromagnetic solenoid
Implementation Method 3
A relief passage extending to a suction chamber (suction pressure region) is formed in the valve body. The pressure (suction pressure) in the relief passage acts on the engagement part joined to the bellows.
Data Source
Figure 1
Figure 2
Figure 3A~3C
AI summary
A displacement control valve for a variable displacement compressor. The displacement control valve includes a drive force transmission body, a pressure sensitive chamber, an internal passage, and a valve body. The valve body includes an annular seal which is contactable with a valve seat surface facing toward the first valve body. The drive force transmission body includes a drive rod and a valve body structure having a shaft passage and forming the first valve body. The drive rod is fitted to the shaft passage and coupled to the valve body structure so as to form a gap passage between an outer surface of the drive rod and a wall surface of the shaft passage. The internal passage includes a recess arranged radially inward from the annular seal, the shaft passage, and the gap passage. The gap passage is in direct communication with the recess.