1, ventilation system, its role is in the car must assure indoor and ventilated, for car interior into the fresh air, constantly drive row mixed with dust, carbon dioxide and harmful gas from engine.In the cold winter, also deal with fresh air is heated, in order to keep the indoor temperature is appropriate.2, heating system: the role of car indoor air or from outside into the fresh air in the car interior heating, heating and dehumidification.3, the refrigeration system: the role of environment that is outside the car at high temperature to reduce the temperature inside the car, make passengers feel cool and comfortable.4, air purification system: the role of air filter, the introduction of continuously eliminate indoor foul gas, to keep the car clean air.5, control system, control system is mainly composed of electrical components, vacuum line and operating mechanism.Its effect on the one hand is to put pressure on refrigeration and warm wind system to control the temperature, pressure, on the other hand is to the car indoor air temperature, air velocity, flow control, to perfect the functions of air conditioning system.