Table of contents: Description of the climate control… ↓ Description of the refrigeration unit ↓ Safety precautions when servicing a… ↓
Description of the climate control system
The location of the climate control system components is shown in Figures 8.1ad. On models with the system "Start-Stop" an additional air humidity sensor "G355" is installed at the base of the interior mirror.
8.1a. Climate control system components not located in the passenger compartment:
1 - Sensor G17 outside air temperature, accessible through the opening between the front bumper cover and the condenser;
2 - Capacitor, different versions available;
3 - Receiver with a dehydrator insert, is part of the condenser, the insert is replaced separately;
4 - Radiator fan V7 and its control unit J293;
5 - Air intake chamber casing with air intake grille;
6 - Air quality sensor G238, not on all models;
7 - Air conditioning system intake casing;
8 - Expansion valve for the evaporator in the front housing of the air conditioning system, under the instrument panel;
9 - High pressure refrigerant sensor G65;
10 - Heated windshield, ready for serial use;
11 - Air intake chamber gutter;
12 - Upper hatch with solar battery used for autonomous circulation mode (is being prepared for serial use);
13 - Sticker with the type and amount of refrigerant;
14 - Air outlets, left and right under the rear bumper;
15 - Service ports for high and low pressure circuits, for measuring, draining and charging refrigerant;
16 - Coolant circulation pump V50, only on models with additional heating;
17 - Coolant pump V36, only on V6 petrol models;
18 - Refrigerant line outlet to the evaporator in the rear housing of the air conditioning system;
19 - Coolant temperature sensor G454, not on all models;
20 - Compressor control valve N280;
21 - Compressor, there are different types.
8.1b. Climate control system components located on the left side of the passenger compartment:
1 - G107 solar radiation sensor, not on all models;
2 - Windshield deflector;
3 - Non-directional deflector, only on models with the "Deluxe" system;
4 - Air vents in the rear of the center console;
5 - Central deflectors in the instrument panel;
6 - Front air conditioning control unit J255 "Basic";
7 - Temperature sensor G56 and its fan V42, only on models with the "Deluxe" system;
8 - Front control unit J255 for the "Deluxe" climate control system;
9 - Heating element Z45 and temperature sensor G344 of the front left seat, not on all models;
10 - Temperature sensor G261 in the front left footwell, only on models with the "Deluxe" system;
11 - Activator V108 of the air supply flap to the left front footwell, with position sensor G139;
12 - Front climate control housing, different options available;
13 - Heater radiator;
14 - V158 actuator for left temperature flap, with position sensor G220, only on models with the "Deluxe" system;
15 - Activator V107 of the window defroster flap, with position sensor G135;
16 - Activator V299 of the air supply flap through the left side vent, with position sensor G164, only on models with the "Basic" system;
17-Air temperature sensor G385 supplied from the left at chest level, only on models with the "Deluxe" system;
18 - Activator V110 for air supply flap through left central vent, with position sensor G136, only on models with the "Deluxe" system;
19 - Accelerator mechanism (automatic compressor shutdown when the "Kick-down" mode is activated);
20 - Diagnostic connector;
21 - Left air duct in the instrument panel;
22 - Air duct to the front left door, not on all models;
23 - Air duct to the front left door glass;
24 - Instrument cluster with outside air temperature indicator;
25 - Deflector flap actuator 2, with position sensor G330, only on models with the "Deluxe" system.
8.1c. Climate control system components located on the right side of the cabin:
1 - MMI display for controlling the climate control system;
2 - Air duct to the glove compartment, not on all models;
3 - Right instrument panel air duct;
4 - Air duct to the front right door, not on all models;
5 - Air duct to the front right door glass;
6 - Activator V111 of the air supply flap through the right central deflector, with position sensor G137, only on models with the "Deluxe" system;
7 - Sensor G386 for temperature of air supplied to the right at chest level, only on models with the "Deluxe" system;
8 - Activator V300 of the air supply flap through the right side deflector, with position sensor G523, only on models with the "Basic" system;
9 - Opening for connection to the glove compartment, not on all models;
10 - V159 actuator of the right temperature flap, with position sensor G221 (on models with the "Deluxe" system), or V158 actuator of the left temperature flap, with position sensor G220 (on models with the "Basic" system; the right valve is driven by the same actuator, the valves are connected by a shaft);
11 - Evaporator outlet temperature sensor G263;
12 - Activator V109 of the air supply flap to the right front footwell, with position sensor G140 (on models with the "Deluxe" system), or activator V108 of the air supply flap to the right front footwell, with position sensor G139 (on models with the "Basic" system; the right valve is driven by the same actuator, the valves are connected by a shaft);
13 - Hose and air duct to the glove compartment, not on all models 14 Fan control unit L26 17, there are different options (for models with or without additional heating);
15 - Multi-pin connector on housing 16;
16 - Front climate control housing, different options available;
17 - Air conditioning fan V2;
18 - V113 activator of the recirculation flap with position sensor G143, there are different versions;
19 - Intake air temperature sensor G89, only on models with the "Deluxe" system;
20 - Condensate drain hose;
21 - Cabin filter;
22 - Evaporator;
23 - Heater radiator in housing 16;
24 - Heating element Z46 and temperature sensor G345, front right seat, not on all models;
25 - Temperature sensor G262 in the front right footwell, only on models with the "Deluxe" system;
26 - MMI control panel.
8.1d. Air conditioning system components located in the rear of the passenger compartment (only on models with rear climate control housing):
1 - Rear housing of the climate control system;
2 - V80 climate control fan;
3 - Fan 2 control unit J391;
4 - Rear evaporator;
5 - Rear expansion valve;
6 - Condensate drain hose;
7 - V314 actuator for rear temperature flap with position sensor G392;
8 - Bushing for coolant hoses and refrigerant lines;
9 - Activator V240 rear right air flow control flap, with position sensor G390;
10 - Air duct on the rear side of the housing 1;
11 - Rear heater radiator;
12 - Multi-pin connector on the rear side of the case 1;
13 - Activator V239 rear left air flow control flap, with position sensor G389;
14 - Activator V313 rear left temperature flap, with position sensor G391;
15/16 - Sensor G406/G405 for temperature of air supplied from rear right/left vent;
17/18 - Heating element Z12/Z10 and temperature sensor G95/G94 rear right/left seat, not on all models;
19 - Rear climate control unit with display E265;
20 - Air vents in the rear of the instrument panel;
21 - Activator V212 of the air supply shut-off flap from the left B-pillar and to the rear left footwell, with position sensor G329;
22/23 - Actuator V315/V316 left/right chest air flap, with position sensor G315/G316;
24 - Air duct to deflectors 20;
25 - Activator V211 of the air supply shut-off valve from the right B-pillar and to the rear right footwell, with position sensor G328.
The climate control module combines the control panel (with display) and electronic control unit. On models with the "Deluxe" system, the air temperature sensor G56 and the fan V42 for this sensor are integrally integrated into the front module. The display and keys of the front and rear control modules are illuminated by non-replaceable LEDs.
One of the main elements of the climate control system is its housing, which contains the main components: cabin filter, fan, radiator, evaporator (with air cooling function) and air flow distribution flaps. If a rear climate control module is installed, a rear climate control housing with a separate fan, radiator, evaporator and dampers is additionally installed.
To clean the air taken from outside the vehicle from small particles (dust, soot, pollen, etc.) there is a cabin filter that should be replaced periodically (see Chapter 1).
The fan is designed to ventilate the interior, i.e. to increase the intensity of air supply to the car interior: the fan speed can be adjusted. A fan with electronic speed control is used.
To heat the interior, the coolant heated in the engine is passed through the radiators of the air conditioning system, transferring heat to the air passing through it. Coolant flow diagrams are shown in the illustrations Section 1.
A refrigeration unit circulating R134a refrigerant is used to cool the cabin. Air entering the cabin is cooled and dehumidified as it passes through the evaporator, so it is recommended to turn on the refrigeration unit to reduce cabin humidity (for example, to speed up the removal of condensation from glass). The flaps are used to: switch between supply ventilation/air circulation modes, regulate temperature, and distribute air flows in the cabin (to the feet, to chest level, to the glass and to the intermediate zones). Additional adjustment of air flow in the cabin is carried out by means of adjustable deflectors on the instrument panel/rear center console and at the rear of the B-pillars. The flaps are driven by actuators.
The set temperature is maintained based on data from cabin air temperature sensors installed in the front and rear climate control modules. To ensure proper operation of the climate control system, do not cover these sensors.
Some models are equipped with an additional heater that heats the coolant independently of the engine by burning fuel.
Description of the refrigeration unit
The operating diagram of the refrigeration unit is shown in Figure 8.2.
8.2. Operation diagram of the refrigeration unit:
HD - High Pressure Circuit;
ND - Low pressure circuit;
1 - Valve "N280" for compressor flow control, cannot be removed separately;
2 - Compressor;
3 - Compressor drive pulley/module, with anti-blocking protection;
4 - Oil drain plug;
5 - Pressure relief valve, do not remove;
6 - Connection without valve;
7 - Coolant temperature sensor G454;
8 - Capacitor;
9 - Receiver with dehydrator insert;
10 - Refrigerant line connection;
11 - Service valve in the high-pressure circuit (unloading, filling and measuring);
12, 18 - Lid with seal;
13 - Connection to valve;
14 - High pressure refrigerant sensor G65;
15 - Expansion valve for front 16;
16 - Front evaporator;
17 - Service valve in the low pressure circuit (unloading and measurement);
19 - Chamber for damping changes in refrigerant pressure (part of the refrigerant line going to the compressor);
20 - Connection of the high pressure refrigerant line going to the evaporator 23;
21 - Connection in the refrigerant line going to the evaporator 23;
22 - Expansion valve for front 23;
23 - Rear evaporator;
24 - Connection of the low pressure refrigerant line going to the evaporator 23.
Continuously driven variable flow compressor (by a drive belt for auxiliary units from the engine crankshaft or by a separate shaft from the auxiliary unit drive mechanism), sucks in gaseous refrigerant from the evaporator and compresses it. At the same time, the refrigerant temperature rises to between 70 and 110°C. Under high pressure, the refrigerant is directed to the condenser, where the heat from the refrigerant is absorbed by air passed through the condenser fins. Due to this heat loss, the refrigerant changes into a liquid form and is directed from the condenser to the receiver-dryer located on it, which serves as a storage medium and filters out the moisture contained in the refrigerant. The thermostatic expansion valve regulates the amount of refrigerant supplied to the evaporator depending on the pressure and temperature in the evaporator. The expansion valve regulates the flow based on heat transfer so that the refrigerant does not completely change to a gaseous state before it reaches the evaporator outlet. Passing through the evaporator, the air supplied to the car's interior gives off heat to the cold refrigerant and is also dried. Moisture from the air is removed under the car. After passing through the evaporator, the refrigerant changes into a gaseous state. After the evaporator, the refrigerant is sucked back in by the compressor under low pressure.
Compressor oil is used to lubricate the components of the refrigeration unit; it circulates in the system together with the refrigerant. Black and colored sealing rings are used for sealing.
A compressor without a magnetic clutch is used, i.e. when the engine is running, the compressor shaft rotates continuously. This way the compressor operates even when the cooling function is turned off (with minimal power consumption).
The compressor flow rate is regulated by the N280 valve using a PWM signal from the climate control unit, depending on the required capacity of the refrigeration unit. The "N280" valve is built into the compressor at the suction side and changes the position of the articulated disc.
When the refrigerant pressure, determined by the high pressure sensor "G65", increases, the climate control unit increases the speed of the fan "V7" on the radiator and reduces the compressor flow if it is too high (for example, if the engine cooling is insufficient) or too low (for example, in case of a refrigerant leak) refrigerant pressure.
If the compressor is blocked (the shaft jams and stops turning), overload protection is activated. Depending on the compressor temperature, either the coupling will deform or the rubber element will wear out. In either case, the compressor pulley/drive shaft will be able to turn. The seized compressor needs to be replaced. To protect the refrigerant circuit from excessively high pressure (for example, due to charging excess refrigerant) a high pressure refrigerant relief valve installed on the compressor is used. The fact that the refrigerant pressure relief valve has opened can be determined by the small plate that is pressed out at the top of the compressor. In addition, after opening the valve, a stain of refrigeration oil forms around it.
Note: When opening the valve, there is a risk of frostbite in the immediate vicinity.
Do not run the engine unless all refrigerant lines are connected, as this will cause the compressor to overheat and fail due to lack of lubrication. If possible, start the engine only with the refrigeration unit filled. If it is necessary to start the engine with the refrigerant circuit empty, the following conditions must be met: all refrigerant lines must be connected, the compressor must be filled with at least a quarter of the full volume of refrigeration oil, the engine speed must not exceed 2000 rpm, and its running time must be as short as possible (no more than 10 minutes).
After installing a new compressor or after filling with refrigeration oil, before starting the engine. follow these steps:
- Rotate the compressor shaft by hand 10 revolutions - this will prevent damage to the compressor;
- Open the vents, set the air flow to chest level, set the minimum temperature and maximum fan speed;
- Start the engine and let it idle for at least five minutes;
- Turn off the engine.
Safety precautions when servicing a refrigeration unit
Do not open the refrigerant circuit, as refrigerant may cause frostbite if it comes into contact with your skin.
Work on the refrigeration unit must be carried out in a suitably equipped specialized workshop. Servicing of the system's refrigeration unit should only be entrusted to trained technical personnel who are familiar with safe operating procedures using the proper equipment, depressurization procedures, and the collection and storage of automotive refrigerant.
- Avoid contact of refrigerant with skin.
- Wear safety glasses when working near the refrigeration unit.
- If refrigerant comes into contact with your skin or eyes, do not rub the affected area. Immediately rinse the affected area with running cold water for at least 15 minutes and seek qualified medical attention. Self-medication is not allowed.
- The refrigerant is stored in cylinders under pressure. Store the cylinder at a temperature no higher than +50°C. Take measures to prevent the cylinder from falling from a height or being exposed to other situations that could damage it.
- Work should be carried out in a well-ventilated area. The refrigerant evaporates quickly, reducing oxygen availability and making breathing difficult.
- Gaseous refrigerant is heavier than air and collects relatively quickly in low places, such as under a car.
- When the refrigerant burns, a toxic gas is formed. Keep refrigerant away from open flames. Do not smoke when working on the refrigeration unit.
- When welding near a refrigeration unit, do not expose it to high temperatures or open flames. Overheating can lead to increased pressure in the refrigerant circuit and ignition.
- If the refrigerant circuit is not opened within 10 minutes after the refrigerant pressure has been released, pressure may re-emerge due to evaporation of the remaining refrigerant.
- Cleaning the condenser or evaporator with water vapor is not permitted. Only cold water or compressed air should be used.
(The original article is available on the website AUDIMANUAL.ru)