Capacity Control Valve Opening Geometry for Compressor Start-Up
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Solution Overview
Problem
Conventional capacity control valves for variable capacity compressors face challenges in rapidly discharging liquid refrigerant during start-up and controlling control chamber pressure, leading to prolonged start-up times and reduced responsiveness in capacity control.
Innovation Solution
The capacity control valve design includes a first valve part with a small opening area acting as a bottleneck, which is narrowed to decrease refrigerant flow out of the control chamber and increase flow from the discharge chamber, allowing rapid pressure control of the control chamber by adjusting the taper angle without reducing the valve body's stroke width, thereby improving discharge efficiency and responsiveness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the first valve part opening area is increased to improve refrigerant discharge rate, then the discharge rate improves, but the control chamber pressure control responsiveness deteriorates
Solution Approach 1:
The flow passage is segmented into multiple paths with different functions: a first flow passage for rapid pressure control with restricted flow, and a second flow passage for high-volume refrigerant discharge. This segmentation allows each passage to be optimized for its specific function without compromising the other.
Solution Approach 2:
Different regions of the valve system have different opening areas and flow characteristics. The first valve part has a small opening area for pressure control, while the second valve part has a large opening area for rapid discharge. This local differentiation enables simultaneous optimization of both control responsiveness and discharge rate.
2Loss of time
If the valve body stroke width is reduced to decrease refrigerant flow out of control chamber, then pressure control responsiveness improves, but the discharge efficiency deteriorates
Solution Approach 1:
The valve system is divided into two independent valve parts: the first valve part controls pressure by restricting flow with a small opening, while the second valve part handles high-volume discharge. This segmentation decouples the conflicting requirements of responsiveness and discharge efficiency.
Solution Approach 2:
The first flow passage acts as an intermediary mechanism that mediates between the control chamber and the discharge system. It provides rapid pressure control while the second flow passage handles the bulk discharge, preventing the intermediary from becoming a bottleneck.
3Speed
If a large opening area is provided for rapid refrigerant discharge, then discharge speed improves, but the control chamber pressure regulation deteriorates
Solution Approach 1:
The discharge system is segmented into two functional pathways: one optimized for rapid discharge speed with large opening area, and another optimized for precise pressure regulation with small opening area. This allows both speed and regulation reliability to be maximized simultaneously.
Solution Approach 2:
Different local regions of the valve system have different opening characteristics tailored to their specific functions. The discharge-oriented region has large openings for speed, while the control-oriented region has small openings for regulation precision.
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 enables rapid discharge of liquid refrigerant and improved control chamber pressure regulation, reducing start-up time and enhancing the responsiveness of the variable capacity compressor.
Implementation Method 1
a solenoid section S for exerting an electromagnetic driving force on the valve body 181
Implementation Method 2
a pressure sensitive body 178 which is arranged in the third chamber to extend and contract by ambient pressure
Data Source
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AI summary
[Problem] To provide a capacity control valve in which discharge function of a liquid refrigerant in a control chamber at the time of start-up of a variable capacity compressor is improved, the capacity control valve capable of simultaneously achieving reduction of a start-up time of the variable capacity compressor and improvement of responsiveness of capacity control at the time of control. [Solution] In a capacity control valve including: a valve main body 2 having a first valve chamber 7 through which a fluid at control pressure passes and which has a first valve seat surface 31A, and an interior space 4 through which a fluid at suction pressure passes; and a valve body 21 having an intermediate communication passage 26 for communicating the first valve chamber 7 and the interior space 4, and a first valve part 21C for opening and closing the intermediate communication passage 26 adjacent to the first valve seat surface 31A, an opening area of the first valve part 21C is smaller than that of the intermediate communication passage 26.