What is the working principle of an automotive air conditioning expansion valve?

[VanDerek]

The working principle of an automotive air conditioning expansion valve is as follows: 1. The working principle of the air conditioning expansion valve: The thermal expansion valve controls the flow of refrigerant entering the evaporator by regulating the superheat of the gaseous refrigerant at the evaporator outlet. Depending on the balance method, expansion valves are categorized into externally equalized and internally equalized types. In specialized automotive air conditioning systems, due to the evaporator having multiple circuits and using a showerhead-type distributor, the pressure drop is relatively large, resulting in varying temperatures at the evaporator's inlet and outlet. 2. The function of the automotive air conditioning expansion valve: After low-pressure refrigerant vapor is drawn in and compressed into high-pressure, high-temperature vapor by the compressor, it is discharged to the expansion valve via the condenser. The high-pressure, room-temperature refrigerant liquid is then throttled by the expansion valve, transforming into low-pressure, low-temperature vapor that enters the evaporator for heat exchange, enabling the air conditioning vents to blow cold air.