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11.2.1. Principle of operation of the conditioner

Fig. 10.5. The compressor (in a section) with the shaking disks and six pistons: 1 – main adjusting valve; 2 – electromagnetic coupling; 3 – belt pulley; 4 – the shaking disk; 5 – piston; 6 – compression camera

On the car the compressor with the shaking washers is installed. It is located on the left side of the engine and serves for compression under pressure of coolant (about 1 kg) which is in gaseous state. The compressor is put in action by the belt drive from a bent shaft. At compression in the compressor coolant turns into liquid state and moves in the evaporator located in the heater case under the dashboard. There coolant evaporates with energy absorption again thanks to what cold is formed. The air proceeding by the evaporator is cooled about its plates. Then coolant moves in the compressor (fig. 10.5) again. For its best condensation after compression in front of the condenser two additional fans are installed. Power of cooling of the conditioner is regulated by electronics and depends on temperature of external air, temperature in salon and a preset value of desirable temperature.
   Additional information on the conditioner

Fig. 10.6. Access to both additional fans opens after removal of facing of a radiator

Two speeds are provided in additional fans (fig. 10.6). With a pressure of cooling liquid of 20 bars the switch works. Then the relay works, and additional fans receive tension via preliminary resistors. At a temperature of cooling liquid more than +107 °C fans work with the maximum frequency of rotation.
At turning on of the compressor control of turns of idling of the engine in order that it did not stop changes at once. The compressor consumes about 9 kW.
In order to avoid a thermal overload of the engine at a temperature of cooling liquid about +115 °C the compressor is switched-off.
The actuation device of the conditioner obtains information on the frequency of rotation of the compressor from the inductive sensor. The rotations of a shaft of the engine given about frequency arrive in the form of a TD signal from the Motronic system. If the received ratio between two values lies out of the set area, it can mean that the compressor rotates hardly and the belt of the drive of auxiliary units slips on pulleys. In this case there is a protective shutdown of the compressor.
At removal of the engine the closed system of circulation of working liquid of the conditioner which is under high pressure should not be opened without the special equipment. Dolivka of coolant in system is possible only at service station. Therefore at removal of the engine it is recommended to unscrew from it the compressor and pipelines of system together with arms and to fix them sideways in a motor compartment by a wire.
The actuation device of the conditioner has system of self-diagnostics. Information on the arisen malfunctions then can be a schitana from memory of the device at service station.