>> Systems of cooling, heating, ventilation and air conditioning
>> Systems of ventilation, heating and air conditioning
Systems of ventilation, heating and air conditioning
The general information and security measures
The general information
Works on system service should be carried out in the conditions of a specialised workshop.
Function chart of typical system K/V
At all do not open working contour К/В, - at contact with a skin the coolant can cause обморожение!
Air submitted system of ventilation in salon of the car, can be warmed up or be cooled depending on a choice of the user. The heat exchanger of a heater and evaporator K/V settle down in salon, under the panel of devices. 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 controls located on the control panel.
Principle of management of a choice of a temperature mode (on an example of a mode of intensive warming up of salon)
The list of the basic components of systems of heating and air conditioning of salon with the short description of their appointment and functioning principles is more low resulted.
The operating relay of switching-off К/В
The given relay carries out a role of the electric switch closing a chain of coupling of compressor K/V. At achievement in temperature of a cooling liquid of some critical value the engine management module (ECM) develops a special command on which the given relay makes central air switching-off. Five-second compulsory switching-off of compressor K/V can be initiated also by the management module at engine start, and also in a mode of slow dispersal. The relay is among replaced components.
The forcing fan
At the expense of rotation крыльчатки the forcing fan air giving on an input of the heat exchanger of evaporator K/V further submitted to salon of the car according to installations chosen by the operator (with preliminary пропусканием through the heater heat exchanger, or bypassing the last) is provided.
The electromotor of a drive of the forcing fan
The choice of a high-speed mode of the electromotor is carried out by the operator from the control panel functioning of systems of heating/air conditioning. At the operating handle turned in position OFF the chain of grounding of the electromotor remains opened and the fan does not function. In the first (LO) position of the handle force of a current submitted on the electromotor is limited to three resistors of special resistive assemblage, as a result, крыльчатка the fan rotates in низкоскоростном a mode. The further switching between modes М1, М2 and HI provides step-by-step decrease in resistance of resistive assemblage with corresponding increase of speed of rotation крыльчатки.
The compressor provides coolant movement in a refrigerator path of a central air of air. The compressor is located at the left on the block of the engine and is put in action by a belt drive from a pulley of a cranked shaft of the last (through the managing director муфту couplings). Compressor Basic elements are actually compressor knot distributing knot, the managing director муфта couplings and приводной a pulley.
Муфта compressor couplings
Муфта couplings К/В serves as the executive mechanism operating activation of the compressor. Муфта is magnetic and provides activation/deactivation of the compressor at the command of the operator from the switch on the control panel, and also on the special commands developed in certain conditions by the module of engine management (ECM). Муфта coupling of the compressor is among maintainable and replaced components.
The condenser is established ahead of a radiator of system of cooling and is the air-liquid heat exchanger providing heat removal from a working body (coolant) of a refrigerator path of a central air. Intensity of functioning of the condenser is provided for the account прокачивания through the heat exchanger of additional air forced by the special fan. The condenser also is among maintainable and replaced components.
The condenser fan
The fan provides adequate selection of heat from the condenser of a coolant pumped over through the heat exchanger even at the motionless car when the running stream of air completely is absent. A food on приводной the fan electromotor moves through the special operating relay.
Evaporator K/V is placed in the general with the forcing fan, and operating relay of switching-off К/В a casing. The evaporator consists from working on a principle, a return principle of functioning of a radiator of system of cooling, the heat exchanger and the broad valve.
The evaporator heat exchanger
Getting to the evaporator a coolant boils, intensively selecting heat from air banished through the heat exchanger by the forcing fan. Sharp cooling of an air stream is accompanied by condensation to a moisture containing in it. The condensate drops out on heat exchanger plates, whence then is taken away on a drainage path. Thus, the evaporator, besides cooling function, plays also a dehumidifier role. The heat exchanger is among maintainable and replaced components.
The broad valve
The valve provides адиабатическое expansion being in a phase of a liquid of a high pressure of a coolant at its hit in the evaporator. Such expansion appreciably raises intensity of a heat-conducting path from air banished through the heat exchanger. Simultaneously the valve carries out the control of the expense of the coolant arriving in the evaporator, allowing to avoid заливания the heat exchanger.
The servo-driver заслонки an air inlet
At activation by the operator of a mode of air circulation from the control panel the special servomotor provides displacement of the managing director заслонки, giving blocking a path in salon of fresh air. Activation of such mode allows to avoid penetration into the car of badly smelling air, and also to carry out intensive cooling of the salon filled with air, heated by direct solar beams during a car parking.
The circulation mode should be activated only for insignificant time as air repeatedly banished on a closed cycle quickly becomes filched.
Air drained in the evaporator is banished through the heater heat exchanger. Air warming up is carried out at the expense of selection of heat from the hot heat-carrier of system of cooling of the engine banished through the heat exchanger. The choice of a temperature mode is carried out by the operator by rotation of the corresponding handle operating position mixing заслонки, regulating the expense of air banished through a heater.
Connecting hoses and lines of a refrigerator path
Connection among themselves working elements of system K/V is carried out by means of the whole complex of flexible hoses and the metal lines used, accordingly, in низконапорном and высоконапорном contours of a working path of a central air. Lines of communication of a refrigerator path are among replaced components.
The receiver-dehumidifier is located on an exit from the condenser and carries out accumulation of a liquid coolant and removal of a moisture present at it. Further, the drained working body arrives in the evaporator.
The equipment of a refrigerator path service ports allows to carry out a discharge and system K/V gymnastics. The service union of a contour of a high pressure is built in the metal line of communication leaving a receiver-dehumidifier. Низконапорный the service union is included in a piece of the flexible hose connecting a returnable line of the evaporator with the compressor.
Security measures at service of components of a central air
The working path of system K/V is under pressure! Do not try to disunite any штуцерные a socket or to remove separate components without a preliminary discharge of system in the conditions of a specialised workshop. As a working body in system the coolant of type R134a is used, - make sure that at station there is a necessary equipment, suitable for use at service of the central airs working on a coolant of given type. At рассоединении штуцерных sockets of a refrigerator path necessarily put on goggles!
Central air service should be made only by forces of specially prepared experts trained in safe working methods, with application of the appropriate equipment with observance of rules of the depressurization acquainted with receptions of gathering and order of storage of an automobile coolant.
- Coolant R134a widely used now, is much less aggressive, than applied earlier R12. Nevertheless, it remains hazardous to health, - causing burns at hit in eyes and on open sites of a body. Though coolant R134а is not toxic, its steams at inhalation can cause an asthma - at all do not make a system discharge indoors. Remember that pair of a coolant it is heavier than air, - try not to get into time of a discharge of system in a viewing hole;
- At contact of steams of a coolant to an open flame poisonous gas which, mixing up in a certain proportion with air is allocated, can become explosive. The coolant steam inhalation through the lighted cigarette can lead to the most unpredictable consequences;
- Do not suppose coolant hit in atmosphere. Unlike R12 coolant R134а does not cause ozone layer destruction, however promotes hotbed effect development in atmosphere;
- In system K/V the sealing elements made of a special material, intended for work with a coolant of concrete type (for R134а - green colour) are used. For the purpose of prevention of casual hit in a working path of a coolant not that type at system refuelling special transitive nozzles are used;
- System discharge it is necessary to carry out on firm HUNDRED KIA;
- Before carrying out of any works connected with heating of any knots of the car (welding, the soldering, drying after painting, etc.), system K/V should be discharged. Necessity for a system discharge arises also at performance of service of its components;
- At service of components of system K/V necessarily put on goggles;
- At coolant hit on a skin or in eyes do not pound the amazed place, - immediately wash out its plentiful quantity of cold water, then address to medical aid;
- The coolant is in a new cylinder under pressure. Store a cylinder at temperature not above 50°С! Try not to drop a cylinder from height and not to suppose other situations which can lead to its damage;
- Service of components of system K/V should be spent in well aired premise, - the coolant differs high летучестью and the congestion of its steams is capable to result to difficulty of breath;
- At all do not make procleaning of the condenser or the evaporator by means of water steam, - apply to this purpose only cold water or compressed air!