Compressor Switching Valve Layout for Faster Crank Chamber Pressure Release
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Solution Overview
Problem
Conventional variable displacement compressors experience delays in pressure release in controlled pressure chambers due to the flow of refrigerant from the crank chamber into the pressure supply passage, which hinders the rapid decrease in pressure and subsequent movement of the spool, leading to delayed pressure release in the crank chamber.
Innovation Solution
A variable displacement compressor design incorporating a switching valve with a sub valve body that actuates before the main valve body to close the internal passage, preventing refrigerant flow from the controlled pressure chamber into the pressure supply passage, ensuring rapid pressure decrease and preventing delays in pressure release.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the first control valve closes the pressure supply passage, then the refrigerant flows out into the suction chamber via the throttle passage, but the refrigerant flowing from the crank chamber into the pressure supply passage via the internal passage of the spool prevents the pressure from rapidly decreasing, resulting in a delay of movement of the spool
Solution Approach 1:
The spool is divided into a first spool and a second spool that are movable relative to each other. The first spool controls the pressure supply passage while the second spool controls the pressure release passage. This segmentation allows independent control of pressure supply and release, enabling the pressure supply passage to be closed while simultaneously opening the pressure release passage, thereby rapidly decreasing the pressure in the crank chamber and eliminating spool movement delay.
Solution Approach 2:
The second spool is configured to open the pressure release passage in advance before the first spool closes the pressure supply passage. This preliminary action ensures that when the pressure supply is cut off, the pressure release passage is already open, allowing the pressure in the crank chamber to decrease rapidly without delay, thus preventing the delay of spool movement.
2Reliability
If the pressure supply passage is closed, then the refrigerant should rapidly decrease in pressure, but the communication between the pressure supply passage and the internal passage of the spool causes refrigerant to flow back, preventing rapid pressure decrease
Solution Approach 1:
The spool is segmented into a first spool for pressure supply control and a second spool for pressure release control. This allows the pressure supply passage and pressure release passage to be controlled independently, ensuring that when the pressure supply passage is closed, the pressure release passage is simultaneously opened, achieving reliable and rapid pressure release without refrigerant backflow.
Solution Approach 2:
The second spool acts as an intermediary mechanism that coordinates between the pressure supply closure and pressure release opening. It ensures that the pressure release passage is opened in response to the pressure supply closure, mediating the transition to achieve rapid and reliable pressure release while preventing refrigerant backflow into the pressure supply passage.
Data Source
AI summary
A variable displacement compressor capable of preventing delay in pressure release of a controlled pressure chamber, such as a crank chamber. A switching valve (350) disposed downstream of a control valve of a pressure supply passage includes a main valve body (352) and a sub valve body (400). The main valve body (352) includes an internal passage (352d) providing communication between a first valve hole (104e1) communicating with a pressure supply passage (145a) between the control valve and the switching valve (350), and a second valve hole (151a) communicating with a pressure supply passage (145b) between the switching valve (350) and the crank chamber. The main valve body (352) provides communication between the second valve hole (151a) and a pressure release hole (351a1) communicating with the suction chamber, when pressure Pm in the pressure supply passage (145a) is lower than pressure Pc in the crank chamber. The sub valve body (400) closes the internal passage (352d) of the main valve body (352), when pressure Pm is lower than pressure Pc. The sub valve body (400) is lighter than the main valve body (352), and thus, when pressure Pm decreases, the sub valve body (400) actuates before the main valve body (352), to close the internal passage (352d) of the main valve body (352).