Attention. The air conditioning system should only be serviced by trained technicians trained in safe operating procedures using the proper equipment and proper depressurization procedures. familiar with the collection methods and storage procedures for automotive refrigerant.
The air supplied by the ventilation system to the vehicle interior can be heated or cooled depending on the comfort conditions selected by the driver and passengers. The heating and air conditioning systems are separate, but the units and components of these systems are located in the passenger compartment in one housing. instrument panel.
The heat generated when the engine is running. transmitted by the coolant to the heater radiator located in the passenger compartment. The supplied air flow from the ventilation system passes through the radiator and is heated by the heat of the engine coolant flowing inside the radiator.
The air conditioning system removes excess heat and moisture from the interior according to basic physical principles. The refrigerant circulating as a liquid in the high-pressure part of the system evaporates and turns into a gas in the low-pressure part. When the gas expands, cooling occurs, accompanied by the removal of heat from the air supplied by the fan to the passenger compartment, and a decrease in its temperature. Then, as the refrigerant passes through the condenser, it releases the absorbed heat to the surrounding air. The heat extraction cycle continues indefinitely as the refrigerant circulates through a closed circuit. Moisture is removed from the air supplied to the cabin due to condensation on the evaporator of the refrigerator compartment.
To perform most air conditioning system repair and maintenance operations, special equipment and certain operating skills are required.
To prevent fresh air from entering the vehicle interior, there is an air recirculation mode.
The source of increased danger when the system is not properly maintained by untrained technicians and when improper equipment is used is high pressure and chemical exposure of the refrigerant. To protect the environment, in accordance with current legislation, only R134a refrigerant can be used in air conditioning systems.
In order to increase the efficiency of the air conditioner, a special algorithm for exchanging information between the injection computer and the air conditioning computer has been developed.
When the air conditioner is turned on, the idle speed increases to improve its efficiency. Engine idle speed is adjusted to compensate for changes in engine load due to the compressor clutch engaging and disengaging.
When the coolant temperature is very high or. If the engine is running under a significant load at a high crankshaft speed and high coolant temperature, turning on the air conditioning compressor is prohibited.
If, with the accelerator pedal pressed all the way, the engine speed is below a certain threshold value, the air conditioning compressor is prohibited from turning on for 20 seconds in order to obtain the maximum possible engine torque.
Note. If, during the prohibition of turning on the air conditioner, one of the two conditions that determined its introduction is canceled, the compressor is turned on automatically until the prohibition time expires.
Precautions when working with air conditioning system components
- Avoid contact of liquid refrigerant with skin or eyes. Eye protection should be worn as standard safety precautions when working with refrigerant. If refrigerant comes into contact with clothing or protective equipment, immediately rinse the affected area with plenty of water
- All work on the air conditioning system must be carried out in a well-ventilated area, since the refrigerant gas is heavier than air and can accumulate in the inspection hole if the air conditioning system is accidentally discharged. Before servicing the system, ventilate the work area.
- A car equipped with an air conditioning system can be heated after painting in a drying chamber to a temperature of 80°C for no more than 20 minutes.
- When washing the engine, do not direct the steam jet at the air conditioning system components
- Use only the recommended oil to lubricate the air conditioning system components, otherwise the system may be damaged.
- To check the tightness of the air conditioning system, use an electronic sensor. Be aware that R-134a refrigerant decomposes when exposed to flame, releasing a highly toxic gas.
- Soldering and welding of air conditioning system components is strictly prohibited.
Notes when replacing air conditioning system components
- Never open the circuit or disconnect components of the air conditioning system before discharging the system.
- After disconnecting the air conditioning system components, immediately close the connections with appropriate caps to prevent moisture from the air from entering the system.
- When installing new air conditioning system components, remove them from their packaging immediately before installation.
- Always use new O-rings when connecting open fittings.
Pic. 14.9. Air conditioning system diagram:A - car interior; B - engine compartment; C - outside air; D - cooled air to the air flow mixing unit; E - heated outside air; F - outside or recirculated air; 1 - compressor; 2 - condenser; 3 - receiver-dryer; 4 - three-function pressure switch; 5 - valve for releasing gas under high pressure; 6 - valve; 7 - thermostatic valve control; 8 - evaporator; 9 - valve for releasing gas under low pressure; 10 - electric heater fan; 11 - electric fan of the engine cooling system; 12 - engine radiator; 13 - liquid under high pressure; 14 - low pressure gas; 15 - high pressure gas