5.2. Systems of ventilation, heating and air conditioning

General information and security measures

See also Part of the Device of ensuring comfort.

The air given by system of ventilation to interior of the car via the filter can be warmed up or cooled depending on the choice of the user. The heat exchanger of a heater and the K/V evaporator settle down in salon, in the case under the dashboard. All stream of the air given to salon goes for heating or cooling through the same casing. Temperature and speed of a stream of air is regulated by means of the governing bodies located on the control panel.

Heat generated during the operation of the engine is transferred by cooling liquid to the heat exchanger of system of heating located in salon. The air given to salon is banished via the heat exchanger and heats up heat of the cooling liquid proceeding in the last. Intensity of heating is regulated by means of mixing in a certain ratio of cold and hot air due to change of position of the mixing gate equipped with the servo-driver.

The used air is removed from salon through the air vents equipped with backpressure valves.

Control of a consumption of the air banished via the heat exchanger is exercised due to the choice of the high-speed mode of the fan of a heater.

In case of need giving in salon of external air can be blocked by inclusion of the mode of circulation (see the Part of the Device of ensuring comfort).

Air conditioning system of salon

Function chart of the K/V typical system

1 — the heater Fan
2 — the Evaporator
3 — the Broad valve
4 — the Receiver dehumidifier
5 — the condenser Fan
6 — the Condenser
7 — the Compressor
and — External air
b — the heated air which is Taken away outside

with — not cooled, forced by the fan
d — the Cooled air coming to salon
And — Gas of high pressure
In — Liquid of high pressure
With — Liquid of low pressure
D — Gas of low pressure

The function chart of the typical air conditioning system is given on an illustration above. Works with air conditioning system have to be performed by a specialized workshop. Do not open a working contour at all To/in, - at contact with skin coolant can cause a frostbite.

By means of air conditioning system air temperature in salon can go down lower than the ambient temperature. One more K/V function is decrease in humidity of the air given to salon during wet weather: air at first is cooled, then again heats up to the set temperature. Drainage of air allows to remove quickly condensate from glasses.

The K/V system consists of the condenser located before a radiator of the cooling system, the evaporator located in the general casing with the heat exchanger of a heater, the compressor, a receiver/dehumidifier, and also the refrigerator tubes connecting the listed above components. On an entrance of the evaporator the throttle valve providing pressure difference necessary for functioning of system is installed. As working liquid in a path of the K/V system the coolant like R134a changing the aggregate state depending on a combination of the defining parameters (temperature and pressure) is used.

The fan provides supply of saloon air to the evaporator functioning by the principle, the return principle of functioning of a radiator in which heat is selected from air and is transferred to coolant. Being warmed, coolant evaporates and at the exit from the evaporator turns into gaseous state.

The compressor of the conditioner is given to rotation from a bent shaft of the engine by means of the belt drive and provides in a working path of system excessive pressure to 30 atm. As a result of adiabatic compression the coolant which is in gaseous state, heats up. Coming to the condenser, coolant is cooled with a through stream of external air and, converted into liquid of high pressure. At a transmission through a throttle pressure of liquid coolant is dumped. Further, coolant evaporates in a contour, at the same time strongly being cooled and, passing through the evaporator, selects heat from the air blown through it. The cooled air moves in interior of the car. As a result of heating in the evaporator coolant turns into gas of low pressure and again comes to the compressor then process repeats.

Security measures at service of components of air conditioning system

The system is under pressure! Do not try to disconnect any tubes concerning the air conditioning system previously without having removed from it working liquid. Removal of liquid from system - rather difficult operation which has to be carried out at the station of service. In system there is a coolant of the R134a type. Make sure that at the station there is necessary for this purpose like coolant an equipment. Use goggles, disconnecting system tubes.

Air conditioning system has to be served by exclusively prepared technicians trained in safe working methods, with use of the appropriate equipment with observance of rules of depressurization, acquainted with methods of collecting and order of storage of automobile coolant.