In order to obtain the required air temperature, the fresh air is cooled by passing through the evaporator or, respectively, heated by passing through the heater core, and in vehicles with a TDI engine through an additional heating element.
The heat generated during engine operation is transferred by the coolant to the heater radiator located in the passenger compartment. The intake airflow from the ventilation system passes through the radiator and is heated by the heat of the engine coolant flowing inside the radiator. On vehicles with a TDI engine, due to its low heat output, an additional electric heater is installed, which, if necessary, heats the coolant.
The air conditioning is affected by the ratio of the components of cold and warm air mixed depending on the position of the respective dampers. All shutters are driven by small electric motors.
Body ventilation is provided by the formation of a through air flow. Fresh air enters the car through an air intake located in front of the windshield. The air flow exits through the exhaust channels located under the rear bumper.
To prevent fresh air from entering the car interior, there is an air recirculation mode.
Operation of the air conditioner
The air conditioning system removes excess heat and moisture from the passenger compartment in accordance with basic physical principles. refrigerant (R 134 a), circulating as a liquid in that part of the system where high pressure is maintained, evaporates and turns into a gas in the low pressure section. 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. Further, as it passes through the condenser, the refrigerant gives off the absorbed heat to the surrounding air. The heat extraction cycle continues indefinitely as the refrigerant circulates in a closed circuit. From the air supplied to the passenger compartment, moisture is removed due to condensation on the evaporator of the refrigerator compartment.
The cooling rate depends on the set temperature and the fan capacity. Adjustment is carried out by smoothly changing the fan speed depending on the temperature difference between the set temperature and the temperature in the car interior.
The air conditioning system uses a solar sensor located in the center of the instrument panel, under the windshield. With intense solar radiation, the sensor increases the fan speed and the air flow supplied to the car interior.
Electronic regulation is integrated into the control panels of the air conditioner.
Attention. Repairs to the refrigerant circuit of the air conditioner are not included. This work must be carried out at a service station.
Safety instructions
- The air conditioning system must only be serviced by trained technicians who are trained in safe work practices using the proper equipment, following depressurization procedures, and who are familiar with the collection and storage of automotive refrigerant.
- It is not recommended to open the refrigerant circuit of the air conditioner, as the refrigerant may cause frostbite if it comes into contact with the skin.
- If refrigerant comes into contact with the skin, immediately flush the affected area with cold water for at least 15 minutes. Contact a doctor or health facility immediately. Self-medication is not allowed.
- The gaseous refrigerant is heavier than air and must collect relatively quickly at the bottom, such as under a car. The refrigerant evaporates quickly, resulting in reduced oxygen supply and difficulty breathing. Work should be carried out in a well-ventilated area.
Pic. 13.1. The main elements of the air conditioning system
A - dust and pollen filter
B - space at the feet of the front passenger,
C - channel for fresh air,
D - evaporator,
E - radiator (heat exchanger) heater,
F - additional heating element,
G - driver and front passenger space,
H - to the nozzle in the instrument panel,
J - to the nozzle under the windshield,
K - to the nozzle in the footwell of the rear passengers,
L - to the nozzle in the footwell,
M - wire mesh
1 - dampers for adjusting the amount of air flow,
2 - fresh air damper,
3 - damper for changing air temperature 1,
One each for the driver and front passenger side.
4 - damper for changing air temperature 2,
One each for the driver and front passenger side.
5 - central damper,
6 - heater damper,
7 - footwell damper.
Pic. 13.2. Air conditioning system diagram
1 - compressor,
2 - electromagnetic clutch,
3 - oil drain plug,
4 - overpressure valve,
5 - push button switch for air conditioner and electromagnetic clutch,
6 - connection with the valve,
7 - capacitor,
8 - screwing into the refrigerant line,
9 - cap,
10 - service connection,
On the high pressure side.
11 - throttle assembly,
12 - evaporator,
13 - cap,
14 - service connection,
On the low pressure side.
15 - catching capacity,
HD - high pressure side,
ND - low pressure side.
Pic. 13.3. The location of the elements of the air conditioning system in the passenger compartment on the driver's side
1 - actuator for the temperature control flap on the left side,
2 - outlet air temperature sensor,
In legroom.
3 - additional heating element,
Only for vehicles with TDI engine.
4 - heat exchanger,
5 - Kick-Down switch,
Only for vehicles with automatic transmission. Depending on the vehicle speed and the desired acceleration, the air conditioning solenoid valve can be switched off by the engine control unit.
6 - diagnostic connector,
7 - left outlet air temperature sensor,
8 - left ventilation nozzles,
9 - nozzles for defrosting glass on the left side,
10 - outdoor temperature indicator
11 - nozzles for defrosting the windshield,
12 - solar sensor,
To control the operation of the air conditioner depending on the amount of solar radiation.
Comment. Since 9/98, the air conditioning system has been slightly modified.
Pic. 13.4. Location of elements of the air conditioning system in the passenger compartment on the front passenger side
13 - control panel,
The indicator and control buttons are illuminated by LEDs, which cannot be replaced.
14 - air temperature sensor in the passenger compartment,
15 - evaporator,
16 - nozzle,
17 - central damper actuator,
18 - executive motor of the right temperature damper,
19 - actuator damper heater
20 - fresh air supply fan,
21 - right temperature sensor of the air entering the passenger compartment,
22 - right ventilation nozzles,
23 - glass defrost nozzles on the right side,
24 - fresh air temperature sensor,
25 - pressure valve actuator,
26 - fan controller,
27 - collection of water condensate,
28 - medium ventilation nozzles
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