The bus automatic air conditioning system consists of five parts: refrigeration system, heating system, ventilation (air distribution) system, automatic control system, and air purification system.
1. Bus air conditioning and refrigeration system
The refrigeration system consists of compressors, condensers, expansion valves, evaporators and other components. The cooling method adopts the vapor compression type, which uses the heat absorbed by the refrigerant when it evaporates to reduce the temperature inside the vehicle. The evaporator as a cooling source has a temperature lower than the dew point temperature of the air (the temperature at which the water vapor in the air becomes dewdrops), so the refrigeration system also has the functions of dehumidification and air purification, making the air in the car cool.
2. Bus air conditioning and heating system
The heating system mostly adopts the cooling liquid heating type. The cooling liquid from the engine water outlet is passed into the warm air water tank, and the hot air around the water tank is blown into the car with a blower. The warm air also defrosts and defogs the front windshield.
3. Bus air conditioning and ventilation system
The ventilation system is a device that can inhale fresh air, mix cold air, warm air and fresh air, and distribute the mixture to different positions in the cabin. There are mainly air supply ducts, dampers and other components. At present, the most widely used ventilation system is the full air-conditioning method, that is, after the air outside the car and the air in the car are adjusted by the damper, they are cooled and dehumidified by the evaporator, and part of the air enters the heater. inside the car.
4. Bus air conditioning automatic control system
On the one hand, the automatic control system controls the temperature of cooling and heating, and on the other hand, it measures and controls the temperature, air volume and flow direction of the air in the car. It consists of three parts: sensor, control center and actuator.
Sensors include temperature selectors, sunlight intensity sensors, damper position sensors, etc. The control center has three types: electronic amplifier, bridge comparison calculator and ECU. Solenoid valves, vacuum converters, vacuum drives, servo motors, etc. belong to the executive components.
5. Bus air conditioning and air purification system
The bus air purification system is generally composed of air filters, electronic dust collectors, anion generators, etc., which filter and purify the air flowing into the car, and continuously discharge the dirty gas in the car. The task of air purification in the bus is done by the evaporator.
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