5.2. Systems of ventilation, heating and air conditioning
General information and security measures
The air submitted by system of ventilation to salon of the car through the filter, can be warmed up or cooled depending on a choice of the user. The heat exchanger of a heater and the To/in evaporator settle down in salon, in the case under the dashboard. All stream of air submitted to salon goes for heating or cooling through the same casing. The temperature and speed of a stream of air is regulated by means of governing bodies located on the control panel.
Heat allocated at operation of the engine, is transferred by cooling liquid to the heat exchanger of system of heating located in salon. Air submitted to salon is banished via the heat exchanger and heats up heat of cooling liquid proceeding in last. Intensity of heating is regulated by means of mixing in a certain ratio of cold and hot air at the expense of change of provision of the mixing zaslonka equipped with the servo-driver.
The used air is removed from salon through the ventilating openings equipped with return valves.
Management of a consumption of air banished through the heat exchanger is carried out at the expense of a choice of a high-speed mode of the fan of a heater.
In case of need giving in salon of external air can be blocked by a way of inclusion of a mode of circulation (see. Part of the Device of ensuring comfort).
Central air of air of salon
Function chart of the K/V typical system
The function chart of typical central air of air is presented on an illustration above. Works with central air should be carried out by a specialized workshop. At all do not open a working contour To/in, - at contact with skin the coolant can cause frostbite.
By means of central air air temperature in salon can go down below ambient temperature. One more To/in function is decrease in humidity of air submitted to salon in crude 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 To/in system consists of the condenser located before a radiator of system of cooling, 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 components listed above. On an entrance of the evaporator the throttle valve providing pressure difference, necessary for system functioning is established. As working liquid in a path of To/in system the coolant of the R134а type changing the modular condition depending on a combination of defining parameters (temperature and pressure) is used.
The fan provides supply of salonny air to the evaporator functioning by a principle, a return principle of functioning of a radiator in which heat is selected from air and is transferred to a coolant. Being warmed up, the coolant evaporates and on an exit from the evaporator passes to a gaseous state.
The compressor of the conditioner is given in rotation from a cranked shaft of the engine by means of a belt drive and provides in a working path of system superfluous pressure to 30 atm. As a result of adiabatichesky compression the coolant which was in a gaseous state, heats up. Arriving in the condenser, the coolant is cooled with a through stream of external air and, converted in liquid of a high pressure. At a transmission through a throttle pressure of a liquid coolant is dumped. Further, the coolant evaporates in a contour, at the same time strongly being cooled and, passing through the evaporator, selects heat from air blown through it. The cooled air moves in car salon. As a result of heating in the evaporator the coolant turns into gas of low pressure and again arrives in the compressor then process repeats.
Security measures at service of components of central air
The system is under pressure! Do not try to disconnect any tubes concerning central air of air, previously without having removed from it working liquid. Liquid removal from system - rather difficult operation which should be carried out at service station. In system there is a R134a type coolant. Be convinced that at station there is necessary for this purpose such as a coolant an equipment. Use goggles, disconnecting system tubes.
Central air should be served by exclusively prepared technicians trained in safe working methods, with use of the appropriate equipment with observance of rules of the depressurization, acquainted with receptions of collecting and order of storage of an automobile coolant.
- The coolant of R134a which is using now, is much less aggressive, than a coolant of the R12 type used earlier. Nevertheless, it is very hazardous to health, - at hit in eyes and contact with skin the coolant can cause burns. Though R134а coolant also is not toxic, its pairs can cause asthma - at all do not make a system discharge indoors. Remember that pair of coolant it is heavier some air, try not to get into time of a discharge of system in a viewing hole;
- At contact паров a coolant with an open flame poisonous gas which, mixing up in a certain proportion with air is allocated, can become explosive. Coolant steam inhalation through the lit cigaret can lead to tragic consequences;
- Do not allow coolant hit in the atmosphere. Unlike R12 the coolant of R134а does not cause destruction of an ozone layer, however promotes development of greenhouse effect in the atmosphere;
- In To/in system the sealing elements made of a special material, intended for work with a coolant of concrete type (for 134а - green color) are used. For the purpose of casual hit to the working highway of a coolant not that type when filling system special transitional nozzles are used;
- The discharge of system should be carried out on firm HUNDRED Mercedes-Benzs;
- Before carrying out any works connected with heating of any knots of the car (welding, the soldering, drying after painting), the system should be discharged. Need for a discharge of system arises also in case of performance of service of its components;
- At service of components of To/in system surely put on goggles;
- At coolant hit on skin or in eyes do not pound the struck place, - immediately wash out it plentiful amount of cold water, then address to medical assistance;
- The coolant is in a new cylinder under pressure. Store a cylinder at temperature not above 50°С. Try not to allow cylinder falling from height or other situations which can lead to its damage;
- Service of components of To/in system should be carried out in well aired room, - the coolant differs high летучестью and the congestion паров is capable to give it to difficulty of breath;
- Condenser or evaporator cleaning by means of water vapor is not allowed, - use only cold water or the compressed air.