1 – fan
2 – evaporator
3 – throttle
4 - connection point to the low pressure circuit during maintenance
5 - connection point to the high-pressure circuit during maintenance
6 - dehydrator tank
7 – capacitor
8 – compressor
a - counter air flow for cooling the condenser
b - discharge of heated air into the environment
c – flow of uncooled air through the heater fan
d – flow of cooled air into the car interior
A – high pressure circuit (refrigerant in gaseous state)
B – high pressure circuit (refrigerant in liquid state)
C – low pressure circuit (refrigerant in liquid state)
D – low pressure circuit (refrigerant in gaseous state)
With the help of the air conditioning system, the air temperature in the passenger compartment can be lowered below the ambient temperature. The fully automated system maintains any set temperature constant, the air flow distribution and the amount of incoming air are regulated by the electronic control unit regardless of the vehicle speed: information about the air temperature in the passenger compartment and outside is transmitted to the control unit using various temperature sensors. In addition, in accordance with the program-set values, the actuators control the position of the air flaps and the fan performance, thereby regulating the climate in the passenger compartment. If malfunctions occur in the control unit, sensors and actuators, the corresponding error codes are entered into the error code memory of the control unit. When troubleshooting at a BMW service station, these codes can be read using a special diagnostic device.
Operation of the air conditioning system
The compressor is driven by a poly V-belt from the crankshaft. It increases the pressure in the circulation circuit to 30 bar, due to which the gaseous refrigerant is heated. The air washing the condenser (cooling air remains outside) takes away heat, as a result of which the hot gas cools and condenses - the refrigerant becomes liquid. It flows under still high pressure throttle, after which the pressure decreases. At the same time, the refrigerant in the circulation circuit expands and at the same time cools even more. In the evaporator, the refrigerant takes away heat from the air washing the evaporator, as a result of which the air cools. This cooled air then enters the car interior. Due to the heat received in the evaporator, the refrigerant becomes gaseous and under low pressure enters the compressor. Thus, the process of refrigerant circulation continues.
Warning: Repair of the air conditioning system is not described. All work on the air conditioning system must be carried out in a specialized workshop. Under no circumstances should the refrigerant circulation circuit be opened, since frostbite may occur if it comes into contact with the skin.
[The original material is located on the website: BMWMAN.RU]