Automotive Air Conditioning
Ⅰ Automotive Air Conditioning and Refrigeration Systems
Using the principle of vapor compression refrigeration, the temperature inside the car can be reduced. The evaporator is the source of cool air in a refrigeration system. Because the temperature of the evaporator is lower than the dew point temperature of the air, it has the function of moisturizing and purifying the air. It is mainly composed of compressor, condenser, expansion valve and evaporator.
The principle of automobile air conditioning refrigeration: low-temperature and low-pressure refrigerant liquid evaporates into low-temperature and low-pressure gaseous refrigerant in the evaporator, which is used to absorb heat in the car and reduce the temperature. After the low-temperature and low-pressure refrigerant vapor is sucked into the compressor, it is compressed into high-temperature and high-pressure refrigerant vapor, and is discharged into the condenser through the high-pressure pipe. It then cools into liquid refrigerant, releasing the heat outside the vehicle. When high temperature and high pressure liquid refrigerant expands, its temperature and pressure decrease. The low-temperature and low-pressure liquid refrigerant evaporates in the evaporator, and the low-temperature and low-pressure refrigerant gas absorbs heat during the liquid-gas conversion process, thereby reducing the temperature inside the vehicle. Then it enters the compressor and circulates like this to lower the temperature inside the car.
ⅡCar Air Conditioning and Heating System
The warm water heating device allows the engine coolant to enter the car heater, and the air in the car can be heated by the blower, which can also defog and defrost the windshield. Automotive air conditioning units are generally of the reheat hybrid type, where the heating systems not only heat the fresh air inside and outside the vehicle; they can also simultaneously cool and then fully or partially heat it to the proper temperature required. This can not only dehumidify the air, but also filter dust in the air and purify the air.
Ⅲ Ventilation System
The core of the ventilation system is the centrifugal blower, which not only heats or cools the air in the car, but also renews the air in the car. Generally, cars have two forms of forced ventilation and natural ventilation. The opening or closing of the fresh air inlet is controlled by the fresh air/circulated air vacuum valve as shown. During natural ventilation, fresh air enters from the air inlet under the front windshield, then enters the trunk through the seat belt notch on the trunk lid, and then is exhausted through the rear apron, trunk lid, and air outlets on the rear longitudinal beam. into the atmosphere. Because the air moves in the rear body cavity, it plays a good role in defrosting the rear window. The difference between forced ventilation and natural ventilation is that the fresh air is pressurized by a blower. When the temperature adjustment damper is closed, it enters the car directly from each air duct without passing through the heater radiator.
ⅣCar Air Conditioning Control System
The automobile air conditioning control system can control the temperature and pressure of the refrigeration system and heating system, as well as the indoor air temperature, air volume and air outlet direction by controlling electrical components, vacuum tubes and operating mechanisms. The control system of automobile air conditioners generally adopts manual lever temperature control method. By pulling the lever on the dashboard to control the opening of the temperature damper, the servo motor and vacuum valve are used to control the opening of the damper to control the temperature inside the car. The control system consists of three parts: electrical control, vacuum control and control mechanism.
1. Electrical control 1) The main control part of electrical control The main control part of electrical control is the compressor electromagnetic clutch, blower and condenser fan motor. (1) Air conditioning compressor electromagnetic clutch control: Chery electronically controlled fuel injection automotive air conditioning engine electromagnetic clutch control third g (2) Fan control: There are two ways to control the fan: the first way is to control the air conditioner by controlling the air conditioning relay The switch turns on the air conditioner and the fan works synchronously; secondly, when the air conditioner is not used, the heater can be used independently because the blower is directly controlled by the switch. (3) Condenser fan motor control: The condenser and radiator share a fan to control the cooling of the engine or air conditioning system under various working conditions. When one of the switches reaches operating condition, the fan can run.
2. Vacuum control In the air conditioning system, except for the temperature which is directly controlled by pulling the control rod, other dampers are controlled by the vacuum valve. The system's control vacuum comes from the engine's intake manifold. When the engine is running, the intake manifold is the source of vacuum, but the degree of vacuum here is constantly changing. In order to reduce vacuum fluctuations and improve the reliability of the control system, a vacuum storage device is installed in the vacuum pipeline. There is also a check valve in the vacuum pipeline, which is a one-way flow control valve. When the one-way valve is open, the absolute pressure in the intake branch pipe is lower than the absolute pressure in the vacuum tank, and the vacuum degree in the vacuum tank increases accordingly; when the one-way valve is closed, the absolute pressure in the intake branch pipe is higher than the vacuum tank The absolute pressure inside the vacuum tank decreases accordingly.
3. Transmission mechanism The operating mechanism of a general automobile air conditioner is mainly through wire drawing and vacuum distributor, and the temperature damper, air conditioning switch, vacuum valve and damper are controlled by knobs. The temperature slider controls the temperature of cold or hot fresh air flowing through all outlets.
ⅤCar Air Conditioning Air Purification System
The core component of the air purification system is the air filter, which can filter the dusty air entering the car and keep the air in the car clean.
