Automotive air conditioning is done to control the temperature, humidity, purity of the atmospheric of the air and circulate the same in the automobile to make the journey of passengers comfortable so that they Should not feel too much cold in winter and too hot in summers. Earliest, most of cars were having the cooling provision only as shown in Figure. It consists of refrigeration system, an air circulation and distribution system and a control system as shown in the layout. It includes the compressor, condensor, dehydrator and connecting lines in addition to expansion valve, orifice tube, suction throttle valve and high pressure cut off switch. The commonly used refrigerant is freon 12 .
The compressor driven by a belt from the engine pulley through an electromagnetic clutch sucks the low temperature and low pressure refrigerant vapour from the evaporator ad compresses it to high temperature and high pressure vapor. Then it is discharged to the condenser Air is caused to flow across the condenser while driving or by the action of the engine fan or a electric fan. Cooling of the refrigerant vapor covers it into liquid at high pressure This liquid is ten stored in the receiver from where, it is passed through dehydrator to extract any moisture the Then the dry refrigerant liquid is passed through the expansion valve mounted at the net side of the evaporator The expansion valve allows the liquid refrigerant to expand to low pressure the evaporator. A sensing device called temperature tube signals the diaphragm in the expansion in valve its e size depending upon the refrigerant at the outlet, temperature evaporator to vary This helps in achieving automatic temperature control.
Air from the blower is forced to low over the evaporator coils Which removes the latent heat of vaporisation moisture and impurities from the air. Condensed moisture from the evaporator and impurities dip into a tray from where they are drained out. The automatic temperature control or manual control system uses the same refrigeration and air during circulation.
In winter season for heating the air, the hot water of the engine is circulated through the pipe coils or through the independent small med under the radiator cooling col. Air is forced by the blower through these coils. The warm air is distributed through the grills in the car. At the time of heating cooling is stopped.
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