The Composition of Automobile Air Conditioning Systems and the Working Principles of Each System
The automobile air conditioning system mainly includes refrigeration system, heating system, ventilation system and air purification system.
1. Composition and working principle of refrigeration system
The work of the air conditioning refrigeration system is the process of continuous gasification and liquefaction of the refrigerant. Taking the center of the compressor and expansion valve as the boundary, the entire refrigeration cycle can be divided into two parts, high and low pressure. The details can be understood through the figure above. The circulation process of refrigerant in the system can be divided into 4 working processes, as follows:
1. Compression. The low-temperature and low-pressure refrigerant gas processed by the evaporator is sucked in by the compressor and compressed into high-temperature and high-pressure gas, and then input to the condenser.
2. Condensation releases heat. The high-temperature and high-pressure refrigerant gas enters the condenser. Due to the reduction in pressure and temperature, the refrigerant gas condenses into a liquid and releases a large amount of heat to the outside atmosphere.
3. Throttle expenditure. The refrigerant liquid with higher temperature and pressure becomes larger in volume after passing through the expansion device, the pressure and temperature drop sharply, and is discharged from the expansion valve in the form of mist (fine droplets). This is the dividing line between high and low pressure of the refrigerant, and the expansion valve has a throttling function.
4. Evaporate. The mist refrigerant liquid enters the evaporator, so the boiling point of the refrigerant is much lower than the temperature inside the evaporator, so the refrigerant liquid evaporates into gas. During the evaporation process, a large amount of surrounding heat is absorbed, and then the low-temperature and low-pressure refrigerant vapor enters the compressor.
By continuing the above process over and over, the purpose of reducing the air temperature around the evaporator can be achieved. At the same time, the blower draws cold air into the car and exhausts the hot air inside the car, thereby lowering the temperature inside the car and achieving a cooling effect.
Air conditioning and heating system composition and working principle
Nowadays, cars mainly make full use of the waste heat of the coolant after the engine is cooled for heating. This method is also usually called water cooling. When the heating effect is required to be higher, the relevant PTC heater will generally be assisted for heating, and finally a good heating effect will be achieved. The main component of the air conditioning and heating system is a heat exchanger, which is mainly used for heating. It heats the air in the car room or the fresh air entering the car room from the outside to achieve the purpose of heating and dehumidification.
As shown in the figure above, the cooling water control valve on the engine sends the diverted cooling water to the heater core of the heater for heat exchange. The heat-released cooling water then flows back to the engine through the heater outlet pipe; at the same time, the cooling water The air is sucked into the heater core by the blower for heating, and blown into the interior of the cabin through different air outlets for windshield defrosting and heating. By controlling the opening and closing of the cooling water control valve and the flow volume, the heat supply of the heater can be adjusted.
