1. Erwarmte Luft - heated air
2. Temperierbare Frischluft - adjustable outside air
Outside air enters the vehicle interior through the air intake grill under the windshield and is blown into the vehicle interior by a fan. In this case, the air passes through the air distributor housing and is directed by means of a system of dampers controlled by cables to the individual air nozzles. If the heating is set to operating mode "warm", cold air is directed to the heater core where it is heated. The radiator is located in the heater housing and is heated by hot coolant. The flowing fresh air is heated by the hot heat exchanger lamellas and then enters the vehicle interior. Heating has a water control mode, that is, the temperature is regulated by the flow section of the radiator with two solenoid valves at the heat exchanger inlet.
The interior temperature can be set with a switch. In accordance with the position of the switch and the current temperature, the electronic unit in the heater control panel regulates the opening time of the valves. Thanks to the presence of electronic control, an approximately constant temperature in the passenger compartment is maintained, regardless of the speed of movement and the outside temperature.
To increase the performance of the heater, a heater fan with four control stages is designed. To ensure different fan speeds, ballast resistors are switched on at different stages. If one of the resistors fails, the fan does not run at the appropriate speed.
The air conditioner consists of a compressor, a condenser, a throttle, an evaporator, a collection tank and a pressure pipe. Frigen or freon is used as a coolant (R12), the latest installations are refueled less harmful to the environment "R134a". The compressor is driven through a wedge or wedge ribbed belt from the crankshaft. It increases the pressure in the refrigeration circuit up to a maximum of 30 bar, which heats up the working gas. In the condenser, heat is removed by the flowing air (cooling air remaining in the outdoor area), which causes cooling and condensation of the working gas. The working substance of the air conditioner becomes liquid. It flows under still high pressure through the throttle, where the pressure is reduced. As a result, the working substance again turns into a gas and at the same time is strongly cooled. In the evaporator, the working gas removes heat from the flowing air. The air is cooling. The cooled air then enters the passenger compartment. The collection tank serves as an expansion vessel for the working substance.
Attention: The description of work with the air conditioner is not given. In addition to maintenance work (compressor drive belt tension) all work on the air conditioner must be carried out in special workshops. It should be especially noted that it is forbidden to open the air conditioning system, as contact with the working substance can cause frostbite. In addition, working medium R12 from FCKW (fluorohydrocarbons) When released into the atmosphere, it destroys the ozone layer.