AC Expansion Valves

AC expansion valves regulate refrigerant flow from the high-pressure liquid line to the evaporator core in vehicle air conditioning systems. These valves meter refrigerant based on evaporator superheat, ensuring optimal cooling performance and preventing liquid slugging. Common designs include thermal expansion (TXV) valves, utilizing a sensing bulb and capillary tube, and electronically controlled valves with stepper motors for precise adjustment. Operation relies on a pressure differential across the valve, controlled by temperature or electronic signals. Materials typically include corrosion-resistant brass, steel, or aluminum alloys, and valve orifice size is critical for system compatibility.