11.17.1. Features of the device
Fig. 11.2. The scheme of the movement of air in the block of heating and air conditioning: 1 – the gate of distribution of a stream of the arriving air (a heater / having blown in glasses); 2 – top gate of distribution of air; 3 – heater heat exchanger; 4 – air temperature regulator gate; 5 – conditioner evaporator heat exchanger; 6 – fan electric motor (electric drive of the supercharger); 7 – entrance gate; 8 – lower gate of distribution of air; 9 – conditioner air duct; 10 – nozzles of an obduv of a windshield; 11 – nozzle of an obduv of side glasses; And – position of the gate for air supply from salon; In – position of the gate for supply of external air
Management of system of heating and ventilation of salon is carried out independently from the air conditioning system when performing function of heating and ventilation of salon, removal of hoarfrost and the condensed moisture from a windshield, an obduv of glasses of doors. At the same time basic elements of a heater work also at turning on of the conditioner. Knots of a heater and the heat exchanger of the evaporator of the conditioner are in one block. The scheme of the movement of air in the block of heating and air conditioning is shown in fig. 11.2.
Main knots of a heater:
– the heater heat exchanger (radiator) intended for heating of the air coming to salon by heat of the liquid cooling the engine;
– the fan with the electric drive (supercharger) providing adjustable supply of external air to gates of a heater and the conditioner;
– the gate of the regulator of air temperature coming from a heater to salon depends on change of its situation amount of the air passing through the heater heat exchanger and the external air passing bypassing the heat exchanger;
– gates of distribution of the air coming from a heater on air ducts to salon or for an obduv of a windshield.
|Fig. 11.3. Control panel of heating and conditioning: 1 – the regulator of temperature of the air coming to salon; 2 – switch of operating modes of the fan of the airsupercharger; 3 – regulator of distribution of streams of air; 4 – back window glass electrical heating switch; 5 – recirculation mode switch; 6 – conditioner switch
The switch of 2 modes of the fan of the airsupercharger works irrespective of position of regulators of distribution of air and temperature and operates fan speed, changing tension in an electric motor power-supply circuit.
The regulator 3 distributions of streams of air, the regulator of temperature and the switch of the mode of recirculation operate heater gates by means of the hummock drive.
The air conditioning system operate the governing bodies located on the panel, the general with a heater (see fig. 11.3
The following elements enter the air conditioning system.
The compressor with the belt drive from a pulley of a bent shaft of the engine. The frictional electromagnetic coupling disconnecting a compressor shaft from a pulley or connecting them during the operation of the conditioner on a signal of an electronic control unit the engine is built in a pulley of the compressor. During the work the compressor compresses the coolant vapors arriving to it from the evaporator heat exchanger to high pressure. Temperature of vapors of coolant on a compressor discharge is much higher, than on an entrance.
The reducing valve is built in the compressor and performs protective function, working at increase in pressure of more admissible value on a compressor discharge. The failure of the valve of high pressure, the electric fan, etc. can be the cause of operation of the reducing valve.
The heat exchanger (radiator) of the condenser located ahead of a radiator of the cooling system of the engine and having a coil with the developed fins for bystry cooling and condensation of the coolant vapors compressed the compressor to high pressure.
The throttle branch pipe (reducer) with mesh filters on an entrance and an exit is installed in the pipeline bringing liquid coolant to the evaporator heat exchanger. The throttle opening in a branch pipe limits a consumption of liquid coolant and reduces pressure in the evaporator. After an engine stop liquid coolant continues some time to flow through a throttle branch pipe from a zone of elevated pressure in a zone of low pressure. Course of liquid through a throttle opening is followed by the characteristic hissing sound which is listened during 30–60 from later stop of the engine and does not testify to malfunction.
Heat exchanger (radiator) of the evaporator. Liquid coolant of the heat exchanger of the condenser through a throttle branch pipe comes to the evaporator heat exchanger located in the heater block. In the heat exchanger liquid turns into gaseous state, absorbing heat. The moisture which is contained in the air arriving to the heat exchanger is condensed on it, flows down from the evaporator and is removed from the heater block. From the evaporator heat exchanger gaseous coolant with impurity of a small amount of liquid fraction of coolant and the thaw of refrigerating oil comes to a receiver which is connected to the output pipeline of the evaporator.
Receiver dehumidifier. In the lower part of the case of a receiver there is a capacity with an absorber of vapors of water from coolant vapors which, being exempted from moisture through a special opening in an intaking tube, mix up with refrigerating oil. In the top part of the case of a receiver are located the union for connection of pipelines. The receiver is not maintainable, it is necessary to replace it only assembled.
Besides the listed elements, are a part of the system valves of high and low pressure, and also pressure sensors.
Fig. 11.4. The schematic diagram of the movement of coolant in the air conditioning system: 1 – conditioner compressor; 2 – condenser heat exchanger; 3 – throttle branch pipe (reducer); 4 – evaporator heat exchanger; 5 – receiver dehumidifier; 6 – a moisture absorber in a receiver; 7 – an opening for mixing of vapors of coolant with refrigerating oil; 8 – the reducing valve in the compressor; And – liquid coolant under high pressure; In – liquid coolant under low pressure; With – gaseous coolant under high pressure; D – gaseous coolant under low pressure
The schematic diagram of the movement of coolant in the air conditioning system is provided on fig. 11.4.
All works on repair of air conditioning system should be performed only at completely discharged system.
As vapors of coolant are toxic, repair system with use of the special equipment which is available in specialized services for service of air conditioning systems.
In connection with specific features of repair of air conditioning system (see the prevention above) in this subsection only works on removal and installation of the control unit of air conditioning system and heating as removal of other elements of knot of heating and conditioning (including a heater radiator) requires full removal of knot from the car with depressurization of air conditioning system are described.