What is the function of a car air conditioning expansion valve?
2 Answers
The expansion valve can throttle and reduce the pressure of high-pressure liquid refrigerant from the liquid storage dryer, regulate and control the amount of liquid refrigerant entering the evaporator to adapt to changes in the cooling load. At the same time, it can prevent compressor liquid slugging (i.e., when unevaporated liquid refrigerant enters the compressor and is compressed, it can easily cause damage to the compressor valve plates) and abnormal overheating of the vapor at the evaporator outlet. Here is additional information: 1. Introduction: The expansion valve is a common component widely used in refrigeration systems. It allows medium-temperature, high-pressure liquid refrigerant to pass through its throttling mechanism to become low-temperature, low-pressure wet steam, thereby controlling the flow rate of the valve. It is often installed at the refrigerant inlet of the evaporator. 2. Classification: There are three main types of expansion valves (throttling devices) commonly used in air conditioning systems: thermal expansion valves, electronic expansion valves, and capillary tubes. Based on structural differences, they can also be categorized into externally balanced expansion valves, internally balanced expansion valves, and H-type expansion valves.
The expansion valve in a car's air conditioning system acts like a smart flow regulator. The refrigerant exits the condenser as a high-pressure liquid and undergoes instant pressure reduction and cooling when passing through this small checkpoint, transforming into a low-temperature, low-pressure mist. This allows the refrigerant to effectively absorb heat in the evaporator, turning hot air into cold air. Without its flow control, the refrigerant would either spray too much, causing pipe blockages due to icing, or spray too little, resulting in insufficient cooling. The valve also automatically adjusts via a temperature-sensing bulb at its top: opening wider when the evaporator outlet temperature is high and closing slightly when the temperature is low. This design ensures both efficient and stable air conditioning cooling, making it the critical hub of the entire system.
