Variable Displacement Compressor Control Valve Flow Rate
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Solution Overview
Problem
Existing control valves for variable displacement compressors face challenges in achieving a large refrigerant flow rate when the sub-valve is open, due to the sub-valve size being constrained by the main valve size, which affects the compressor's starting performance.
Innovation Solution
A control valve design where the sub-valve has a larger inclination of valve opening characteristics relative to the uplift amount, allowing for a larger flow rate when open, while maintaining stable main valve opening characteristics, by separating the sub-valve and main valve elements and using a solenoid to control the main valve closing and sub-valve opening.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the sub-valve size is constrained by the main valve size in a single-solenoid control valve design, then the device complexity is reduced, but the refrigerant flow rate when the sub-valve is open decreases
Solution Approach 1:
The control valve is divided into a main valve and a sub-valve with separate valve elements (main valve element and sub-valve element) that can be independently controlled. The solenoid is segmented into a main solenoid and a sub-solenoid, allowing independent actuation of each valve. This segmentation enables the sub-valve to have a larger opening area without being constrained by the main valve size, thereby increasing refrigerant flow rate during compressor startup while maintaining a manageable overall device structure through modular organization.
Solution Approach 2:
The control valve design integrates multiple functions into a single device: the main valve controls refrigerant flow during steady operation, while the sub-valve provides rapid pressure relief during startup. The shared solenoid actuation mechanism provides universal control capability for both valves, reducing device complexity. This multi-functionality allows the system to achieve both high flow rate capability and structural simplicity.
2Productivity
If the sub-valve opening area is increased to improve compressor starting performance, then the refrigerant flow rate increases, but the device complexity increases
Solution Approach 1:
The control valve is divided into a main valve and a sub-valve with separate valve elements (main valve element and sub-valve element) that can be independently controlled. The solenoid is segmented into a main solenoid and a sub-solenoid, allowing independent actuation of each valve. This segmentation enables the sub-valve to have a larger opening area without being constrained by the main valve size, thereby increasing refrigerant flow rate during compressor startup while maintaining a manageable overall device structure through modular organization.
3Device complexity
If a single solenoid controls both main valve and sub-valve, then the device complexity is reduced, but the control precision for each valve decreases
Solution Approach 1:
The control valve is divided into a main valve and a sub-valve with separate valve elements (main valve element and sub-valve element) that can be independently controlled. The solenoid is segmented into a main solenoid and a sub-solenoid, allowing independent actuation of each valve. This segmentation enables the sub-valve to have a larger opening area without being constrained by the main valve size, thereby increasing refrigerant flow rate during compressor startup while maintaining a manageable overall device structure through modular organization.
Solution Approach 2:
The control valve incorporates pressure-sensing sections that act as intermediaries between the solenoid actuation and the valve elements. These pressure-sensing sections detect pressure differences and generate drive forces that assist the solenoid in controlling the valve openings. This intermediary mechanism enhances control precision by providing feedback-based adjustment, allowing each valve to be precisely controlled despite the simplified single-solenoid actuation system.
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 compressor's starting properties by achieving a larger refrigerant flow rate when the sub-valve is open and maintains accurate control of the compressor's discharging capacity.
Implementation Method 1
a solenoid configured to generate a drive force in a closing direction of the main valve in accordance with an amount of current supplied
Implementation Method 2
a pressure sensing section configured to sense a predetermined pressure to be sensed and configured to generate a drive force exerted in an opening direction of the main valve in accordance with a magnitude of the pressure to be sensed
Data Source
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AI summary
A control valve according to one embodiment includes a body having a main passage communicating a discharge chamber with a crankcase and a sub-passage communicating the crankcase with a suction chamber, a main valve provided in the main valve passage, a sub-valve provided in the sub-passage, a power element for receiving the suction pressure of the suction chamber and generating a drive force exerted in an opening direction of the main valve in accordance with the magnitude of the suction pressure, and a solenoid for generating a drive force in a closing direction of the main valve in accordance with the amount of current supplied. The control valve is configured such that the sub-valve remains closed when the main valve is controlled and such that the sub-valve is opened after the main valve is closed. Also, a change in the area of opening of the sub-valve relative to the uplift amount of the sub-valve element from the sub-valve seat is larger than that of the main valve relative to the uplift amount of the main valve element from the main valve seat.