The automobile air conditioning system uses the vapor compression refrigeration cycle. A compressor is directly driven by an engine, high-temperature and high-pressure refrigerate gas discharged by that compressor enter a condenser through a high-pressure pipe to dissipate heat by temperature difference to form high-temperature and high-pressure liquid, the high-temperature and high-pressure liquid enters an expansion valve through a liquid storage dryer, and the high-temperature and high-pressure liquid become low-temperature and low-pressure gas through throttling, expansion and heat exchange by a preposed evaporator and a top-mounted evaporator, The low temperature and low pressure gas in the system is sucked by the compressor again and compressed into high temperature and high pressure gas to form a circular refrigeration. The cycle is repeated, so that the temperature in the car can be maintained in a more comfortable state.
