The automobile air conditioning system is a device to realize the cooling, heating, ventilation and air purification of the air in the compartment. The automotive air conditioning system is mainly composed of compressor, electric clutch, condenser, evaporator, expansion valve, receiver dryer, pipeline, condensation fan, vacuum solenoid valve, idler and control system. Automotive air conditioning is divided into high-pressure pipeline and low-pressure pipeline. The high-pressure side includes the compressor output side, high-pressure pipeline, condenser, receiver dryer and liquid pipeline; The low-pressure side includes evaporator, accumulator, return pipeline, compressor input side and compressor oil pool.

The working principle of automotive air conditioning is to use the continuous circulation of refrigerant to absorb the heat of the air inside the vehicle and discharge it into the air outside the vehicle through the four processes of compression, condensation, expansion and evaporation, so as to gradually reduce the temperature of the air inside the vehicle. The compressor compresses the refrigerant gas into high-temperature and high-pressure gas, which is cooled into high-pressure and low-temperature liquid through the cooling pipe of the condenser, dehumidified and buffered by the receiver dryer, then flows to the expansion valve at a relatively stable pressure and flow rate, and finally flows to the evaporator through throttling and depressurization. The air in the compartment continuously flows through the evaporator, and the temperature in the compartment is therefore reduced. After flowing through the evaporator, the liquid refrigerant becomes a low-pressure gas again and is sucked into the compressor again for the next cycle