Capacity Control Valve Back-Pressure Relief for Faster Response
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Solution Overview
Problem
The responsiveness of capacity control valves in air conditioning systems is decreased due to the larger pressure receiving area for control pressure on the valve body, leading to energy inefficiency and reduced controllability.
Innovation Solution
A capacity control valve design that includes a valve housing, a solenoid-driven valve body, a spring to bias the valve body opposite to the solenoid's direction, and a flow passage control device using fluid pressure to decrease the pressure on the valve body's backside, improving responsiveness by managing the pressure difference between the fluid pressure and the control pressure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If the control pressure Pc is applied to a larger pressure receiving area on the valve body, then the valve body is biased in the valve opening direction, but the responsiveness of the capacity control valve is decreased
Solution Approach 1:
The pressure receiving surface is divided into two distinct areas: a first pressure receiving area facing the control pressure Pc and a second pressure receiving area facing the suction pressure Ps. This segmentation allows independent control of the forces acting on the valve body, enabling the larger area to provide biasing force while the differential pressure arrangement maintains responsiveness.
Solution Approach 2:
Different regions of the valve body are assigned different functions: the first pressure receiving area is optimized for receiving control pressure to provide biasing force, while the second pressure receiving area is optimized for receiving suction pressure to counterbalance and maintain responsiveness. This local differentiation resolves the contradiction between force magnitude and response speed.
2Force
If the control pressure Pc is higher than the suction pressure Ps, then the control pressure biases the valve body in the valve opening direction, but energy efficiency is decreased
Solution Approach 1:
The pressure difference between control pressure and suction pressure, which initially causes energy loss by continuously biasing the valve open, is converted into a beneficial force. The suction pressure acting on the second pressure receiving area is utilized to counterbalance the control pressure, transforming the harmful continuous pressure differential into a useful equilibrium that maintains valve position without wasted energy.
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 enhances the responsiveness and controllability of the capacity control valve by reducing the influence of control pressure on the valve body, leading to improved energy efficiency and performance.
Implementation Method 1
a valve body to be driven by a solenoid
Implementation Method 2
a spring that biases the valve body in a direction opposite to a direction of driving by the solenoid
Implementation Method 3
a CS valve that includes a CS valve seat and the valve body, and that moves the valve body to open and close a communication between the control port and the suction port
Data Source
Figure 1
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AI summary
There is provided a capacity control valve capable of improving responsiveness. A capacity control valve V includes: a valve housing 10 provided with a suction port 11 through which a suction fluid of a suction pressure Ps passes and a control port 12 through which a control fluid of a control pressure Pc passes; a valve body 51 to be driven by a solenoid 80; a spring 85 that biases the valve body 51 in a direction opposite to a direction of driving by the solenoid 80; a CS valve 50 that includes a CS valve seat 10a and the valve body 51, and that moves the valve body 51 to open and close a communication between the control port 12 and the suction port 11, the capacity control valve V opening and closing the CS valve 50 to control the control pressure Pc, in which the control fluid of the control pressure Pc is suppliable to a back side of the valve body 51, and the capacity control valve V further includes flow passage control device 40 that uses a fluid pressure generated by opening and closing of the CS valve 50 and a pressure on the back side of the valve body 51 to decrease the pressure on the back side of the valve body 51.