Acknowledgement
Preamble
As people's standard of living improves, cars start to move into thousands of homes, and the status of car air conditioning becomes increasingly important. Foreign car air conditioning is moving in the direction of reducing weight, energy consumption and intelligence; while there have been some developments in domestic car air conditioning, there is a significant gap compared to abroad. In particular, at this stage in our country, the autonomous design of auto air conditioning and the development of relevant design software are far behind the advanced levels abroad. The domestic automobile air-conditioning industry should actively introduce advanced design software, follow the path of independent design development, manage the design development and production marketing of car air-conditioning using a scientific management information system, and improve the design capabilities of domestic car air-conditioning as soon as possible, thus contributing to the development of the automobile industry. Moreover, there is a growing demand for the comfort of the car environment, which is met to a certain extent by the ability of car air conditioning to regulate the temperature, humidity, wind speed, cleaning and noise in the car room。
Owing to the high level of development of electronic technology and its extensive use in cars, the structure of air-conditioning systems has become more complex, as have the increased level of electronicization of control components, and many advanced imported vehicles have introduced micro-machine-controlled automated air-conditioning systems. Meanwhile, new refrigerant r134a is replacing refrigerant r12 to meet environmental requirements。
As car air conditioning rates continue to increase, research is important for it。
The main elements of this paper describe the structural principles, failure diagnosis and maintenance techniques of the b5 car air conditioning system in pasat。
Chapter i introduction
1. 1 foreword
Automobile air conditioning means a device for regulating the air in the car's cabs and cars. Automobile air-conditioning systems function to regulate parameters such as the temperature, humidity, flow speed and cleanness of indoor air, to make drivers and passengers comfortable and to prevent or remove fog, frost and ice from windshield glass, to ensure the health and safety of drivers and passengers and thus to create a fresh and comfortable car environment. Air conditioning plays an increasingly important role, especially as recent years have evolved。
In modern vehicles, air conditioning has become a necessary equipment, which, on the one hand, plays an important role in increasing the safe driving of drivers and reducing traffic accidents, and, on the other hand, places higher comfort requirements on the air environment in the vehicles as the demand for quality of life increases. As a result, air-conditioning technology has become more widely used in cars。
1. 2 history of car air conditioning development
Automobile air-conditioning systems are designed to provide cooling, heating, air exchange and air purification of the interior air. It allows for a comfortable car environment for passengers, reduces the fatigue of drivers and improves road safety. Air-conditioning units have become one of the markers for measuring the integrity of vehicles。
As early as 1886, the german karl-benz had more than 110 years since the first third-wheeler in the world. After several revolutions and leapfrogging, the world's automobile industry has made automobiles today an important vehicle for transport and a major pillar of national industries. Car air conditioning, on the other hand, is almost half a century late than car development。
In 1927, the first car air-conditioning unit appeared on the united states market in new york, when the world's car manufacturers were blown up. In fact, it can only be called a “heater”, but it only adds heat to the cars and can provide some heating during the cold european season。
By 1938, the american parder had invented car air conditioning, and he had tested it in an old man's car on the basis of the refrigerator's “cooler”. Also in 1939, improved air-conditioning units were installed in a lincoln v12 car made by ford motors in the united states。
In 1940, the united states company packard, for the first time, used mechanical refrigeration for vehicle air conditioning, opening the way to the world market for car air conditioning。
The outbreak of the second world war hindered the development of car air conditioning. After the end of the second world war, the operationalization and universalization of car air conditioning began to gradually resume。
In 1953, some car manufacturers in the united states officially started using air conditioners in ordinary cars, followed by large volumes of car air conditioning. The number of vehicles equipped with air conditioning at the local level reached 10 per cent of the total, with 50,000 units。
In 1954, the first fully integrated vehicle air-conditioning equipment for cooling and heating was installed in the united states nash minibus。
In 1957, japan also started pilot production of auto air conditioning with reference to the united states, and then european auto manufacturers began to produce car air conditioning。
In 1960, car air conditioning for air-conditioning units began to spread throughout the world. According to statistics, 750,000 units of air conditioning had been installed in cars worldwide by 1962。
In 1964, the first automatic temperature-controlled car air conditioner was installed in a united states general motors cadillac limo。
In 1967, there were 3. 54 million car-conditioning cars worldwide。
After 1971, automotive air conditioning units were installed in luxury cars such as toyota motors, the crown; rolles, england; and mercedes-benz, germany。
In 1979, the united states and japan jointly launched a computer-controlled auto-conditioning system for car air conditioners, which was digitally shown to achieve optimal control. At that time, car air conditioning had entered the fourth generation。
In 1989, the u. S. General motors corporation produced a large number of initial products, mainly specialized circular air-importing surge car air conditioning. As it is difficult to achieve the air cycle, the choice of the external air, the determination of the air outlet, and dehumidification and temperature control, the mainstream is changed to air mixed air conditioning。
In my country, in the 1970s, the oldest car air conditioner was used in the changchun red flag car. In 1976, a car air conditioner was manufactured by the former inner shanghai gas pumping plant at today's shanghai automobile air conditioning plant, accompanied by a shanghai-licensed sedan sh760a
1. 3 functioning and characteristics of car air conditioning
Car air conditioning is a device installed on the vehicle to regulate the air in the cab and car by consuming engine power. Knowledge of vehicle air conditioning characteristics facilitates its use and maintenance. In summary, car air conditioning features are as follows:
1. Large cooling volumes and rapid cooling: (i) a high density of passengers in cars, a high volume of human dispersion and a high heat load; (ii) a high heat load in the sun, a difficult insulation of cars, a large surface area exposed to the sun and glass of doors and windows, and a high amount of heat and difficulty in taking better insulation measures; (iii) in most parts of the country, the temperature in cars rises to more than 50 °c in summer when cars are parked under hot sun for long periods. At such a high temperature, when passengers arrive in the car, they require a rapid reduction in the temperature in the vehicle, which requires greater reserve capacity for car air conditioning, i. E., greater refrigeration requirements. Owing to the short stay of passengers in the vehicle, the requirement for car air conditioners to cool within a few minutes is different from that for room air conditioners。
Power sourced from engines or auxiliary engines: automobile air conditioning is not easy to use as a power source, and motors (known as mainframes) or auxiliary engines must be used to drive compressors, thus making power source processing more difficult than room air conditioning。
3. Large movement of refrigerants: large movement of refrigerants (refrigerants) in systems (host-led air-conditioning systems, vehicle speed changes) should be fully considered in system design。
4. High condenser temperature: the ventilation of the condenser is affected by the radiation heat of the engine's water tank, vehicle speed and road dust contamination. The cooling temperature and condensation pressure are abnormally high, especially when cars are waning or climbing。
Refrigerants are prone to leaks: cars are highly vibrating and connectively loose when travelling on a bumpy road; condensers are vulnerable to pebble blows or mud corrosion and leakage. Automobile air-conditioning malfunctions caused by refrigerant leakage accounted for approximately 80 per cent of all malfunctions and were highly frequent。
Refrigeration units are structurally compact: owing to the tight structure of vehicles, the installation of refrigeration units is very limited, and it is difficult to universalize evaporation containers because of the need for specialized in-vehicle chillers. As a result, evaporation boxes and placements on cars are now varied。
7. Strong impact resistance: automobile air conditioners should be equipped with sufficient strength and resilience, as they are installed in moving vehicles and subject to severe vibrations and frequent shocks。
Chapter ii. The operation of the pasat b5 ac refrigeration system
2. 1 refrigerants
The pasat b5 air-conditioning system uses the chemical name of the new refrigerant r134a, r134a, tetrafluoroethane, with a boiling point of 26. 18°c under standard atmospheric pressure and a non-colour-free gas at constant temperature pressure, with a relative density of approximately 3. 53 times the air density. It is chemically stable and has advantages such as non-combustion and air-blending non-explosion. Attention with refrigerant r134a:
(1) refrigerant r134a has excellent heat stability, but is not soluble with refrigerated oils and is soluble in water, thus causing some difficulty in dry dehydration of new refrigeration systems. On the other hand, r134a and the minerals used in the original r12 were not soluble as refrigerated oil, and therefore only pag oil was used。
(2) changes in compressor components. Swing-board compressors were still used in the new refrigeration system, but because of the high permeability of the new refrigerant, the original nbr/fkm rubber seal was converted to hydrogenized butammonium to improve its sealing performance. Lubricating oils were also replaced with more water-intensive pag or sw100 oils。
(3) add a pressure valve. The valve has many advantages in relation to flammability: pressure protection in case of stress abnormalities while controlling refrigerant discharge. Once pressure has returned to normal, it remains functional and easy to repair。
(4) changes in condensers. The use of new refrigerants resulted in an increase in system pressure and a decrease in condensation. As a result, the new refrigerant system uses tube-banded parallel flow condensers, whose heat transfer efficiency can be significantly improved compared to that of traditional piping condensers。
(5) change of liquid dryer. R134a refrigerants and water are proximate and difficult to dehydrate. Xh-7 and xh-9 modified molecular sifts should be used as dryers. The liquid dryer is also converted from steel to aluminium in tanks to improve corrosion resistance. In addition, the total quantity of drying agents in liquid bottles has increased accordingly。
(6) changes in the evaporation unit. The evaporater's flat tubing is widened, and the length of the wings is reduced. The introduction of r134a has led to an increase in system pressure and temperature, leading to a decrease in refrigeration efficiency, which has required an increase in the evaporation unit to replace the heat area in order to improve the heating conditions。
(7) thermal expansion valve changes. The new refrigeration system introduced advanced h-type thermal expansion valves, replacing the external equilibrium thermal expansion valves used in the original refrigeration system, further increasing the reliability of the system。
(8) tube and rubber materials. R134a refrigerants and pag oils dissolve nbr and kmb rubber hoses and o-type seals, causing expansion and fragmentation. Accordingly, the new ac refrigeration system replaced all rubber pieces with hnbr (hydrobutamino) materials for r134a and pag oils and added nylon layers to the original tube interior。
2. 2 frozen oil
Refrigerant oils participate throughout the air-regulating cycle by melting together with refrigerants and have a lubrication effect on compressors. R12 cannot, however, be dissolved in r134a. If the oil is used for r134a air-conditioning systems, there will be hydraulic shocks, thereby damaging the compressor. The r134a system must therefore use specialized refrigerated oil。
Caution in the use of refrigerated oil: (1) refrigerated oils with different brands cannot be used intermingled, otherwise they may lead to deterioration of refrigerated oils. (2) refrigerator oils are highly water-absorbed, so the tankers used should be tightened immediately. (3) refrigerated oils cannot be used. The reasons for the deterioration of the refrigerator oil are multifaceted, which can be summarized as follows: refrigerator oils are blended into water and produce, in oxygen, an acidic substance of an oilic acid nature (i. E. A swirling substance), which corroses metal parts and components. 2 high temperature oxidation. When compression temperatures are too high, refrigerated oils are decompressed and darkened. 3 add different brands of oil. Chemical reactions resulting from differences in the antioxidants contained in various branded refrigerated oils cause deterioration and damage to their respective refrigerated oil properties. The simple method of checking degenerative oil is to drop the chiller oil slightly onto water-absorbed white paper and, after some time, if there are black spots in the central part of the oil drip, this means that the oil has deteriorated and cannot be used, and it must be replaced with refrigerated oil. (4) refrigerating oils are non-refrigerated and can impede the heat exchanger's heat exchange, so only the specified quantity is allowed and no excess is allowed to affect the cooling effect of air conditioning. (5) use r12 or r134a of refrigerated oils that match them。
The compressor (type 7sb-16) in the pasat b5 air-conditioning system uses the refrigerant r134a, unlike the freon refrigerant, the seals require the use of hydrohydrated butylene rubber, lubricating oils to water-intensive pag refrigerated oils (model g052,300a2), and chiller oils are 250 ml。
2. 3 the operation of air-conditioning refrigeration systems
The cooling system principles for car air conditioning are shown in figure 2-2-1. In pasart b5 air-conditioning systems, r134a, an environmentally non-polluting refrigerant, is used by refrigeration units, which are compressed by compressors into liquid form, enters an expansion valve after cooling by condensers, where the refrigerant is converted from liquid to gas, where it is inhaled from the evaporation unit to large amounts of heat from the vehicle, while reducing the temperature inside the vehicle. Refrigerants re-enter compressors after passing through liquid tanks. In order for compressors to inhale only gaseous refrigerants, gaseous and liquid blends from evaporation units must first enter the liquid storage tanks, allowing the liquid to fully expand to gaseous on the one hand and the refrigerant on the other。
Figure 2-2-1 rationale for air-conditioning refrigeration systems
(b) 2-low pressure tubes;
7 - expansion valves; 8 - pressure switches
Chapter iii structure of the pasat b5 ac system
2. 1 manually regulate the construction of air-conditioning systems
The pasat b5 ac system consists of three components: refrigeration, heating and control. Because refrigeration and warm wind use the same wind delivery system, the two cannot actually be completely separated。
The heating units consist mainly of fresh air winders (v2), heat exchangers and central vents, footspace vents, wind vents for side window windows, frosting nozzles, etc。
When heating occurs, the cooling fluid of the engine passes through the thermal exchanger, which is then delivered to each vent by the fresh air blower (v2) and the heat wind of the heat exchanger according to different heating requirements。
Refrigerators consist of condensers, liquid storage units, compressors installed on engines and evaporation units installed in air-conditioning and heating units in front of vehicles。
Control units are mainly heat and air-conditioning regulators (which contain air-conditioning switches (e35), fresh air drum switches (e9), fresh air and circulation air switches (e184)), air-conditioning cut-off control units (j314) on the left side of the dashboard, ambient temperature switches (f38), fresh and circular air-active locator locator locator locators (v154), wind-drive chains (n24), air-conditioning electromagnetic ionizers (n25), air-conditioning pressure switches (f129)。
3. 1 compressors
The compressor of the air-conditioning system is installed at the front end of the engine and is driven by an engine curvature v belt wheel, which is designed to drive the flow of refrigerants and compress low-temperature, low-pressure gas refrigerants into high-temperature, high-pressure gas refrigerants。
The construction of the compressor is shown in figure 2-2-2 when the electromagnetic ionator is connected, the engine moves through the belt belt, the active axle of the front panel, and the tilt wheel drives the piston upon and below the cylinder, and when the piston moves up, the drain valve on the valve is opened and presses the refrigerant into the pressurized cavity; when the piston moves down the piston, the intake valve on the valve is opened and the inhalant is from the low pressurized cavity. It uses refrigerant r134a, unlike freon refrigerants, seals require the use of hydride butylene rubber, lubricating oils for water-intensive pag refrigerated oils (model g052,300a2), and chiller oils of 250 ml。
The compressor structure is compact, it is small, it is more smooth, efficient and reliable and it is best suited for small high-speed vehicles。
Figure 2-2-2 construction of compressors
3. 2 emci
The construction of an electromagnetic ionator (n25), when the electromagnetic ionator's wiring is in power, produces a magnetic field, which binds the front plate to the belt wheel, which is carried by the engine, while the front plate is connected to the main axis of the compressor and is therefore operated by the motor-driven compressor. When the wire is out of power, there is a gap between the belt wheel and the front plate, where the compressor is no longer operational, which cannot be too large or too small, and if it is too large, the electrical current that needs to be attracted is too large to burn the wire; if it is too small, it may lead to the separation of the belt wheel from the front plate。
3. 3 ac pressure switches
The construction of an air-conditioning pressure switch (f129), which is installed on a condenser, requires the cutting off of an electromagnetic ionator (n25) when the refrigerant in the refrigeration system is insufficient and the compressor is suspended, when the low pressure switch of an air-conditioning pressure switch (f129) works: lines are disconnected when the system pressure is less than 120 kpa and connected when the system pressure is greater than 240 kpa。
When there is excessive pressure in the refrigeration system, the components of the refrigeration system are damaged and the high pressure switch for the ac pressure switch (f129) should function to prevent the system from working under abnormally high pressure and to protect the system from damage. Automatically connect wind fans to high-speed block motion, allowing heat fans to operate at high speed v7 to enhance the cooling capacity of heat fans and reduce the temperature and pressure of systems; when system pressure is below 1250 kpa, heat fans v7 operate at low speed。
3. 4 erosion valve
The construction of the expansion valve is as shown in the figure and the expansion valve is type h. It consists mainly of valves, temperature elements, regulators, springs, ball valves, etc. It is more sensitive to regulation and more efficient to cool because its temperature components are installed directly in the valves and are not affected by the environment and the transport of the heat packs, the inaccuracies of exposure, etc。
When the temperature of the refrigerant from the evaporation unit increases, the sensor pressure attached to the evaporation unit rises, moving down the thin membrane, overcoming the regulating spring force and opening the valve, leading to an increase in the compressor's refrigerant entering the evaporation unit and a decrease in the evaporation unit temperature. To keep the evaporation unit at a low temperature, but not less than 0°c, in order to prevent the frost from blocking the expansion valve. This should normally be achieved at 2-8°c, by adjusting the spring。
Figure 2-2-3 h expansion valve
1-temperature component 2-modulation pole 3-ball valve 4- spring 5-valve body
3. 5 evaporaters
The evaporation unit of the air-conditioning system is generally installed under the miscellaneous boxes on the side of the co-pilot. The function is to evaporate low-temperature low-voltage wet-gas refrigerants from expansion valves into pipes, vaporize them into gaseous refrigerants, absorb large amounts of heat and reduce the temperature of evaporation containers and the surrounding air, while dehumidizing the air。
The structure of the evaporation unit consists mainly of refrigerant flow pipes and dispersors. Three types of piping, taped and stacked (or winged) are common. The structures and materials of the first two evaporation units are essentially the same as those of the condensers, and the stacked evaporation units are composed of two pieces of aluminum plating in complex shapes, each of which is welded into a cobra scattered tropic, and a single layer is welded and then welded into a container. It has the advantage of being structurally compact and heat-efficient. However, its welding process is difficult, its passage is blocked and is now more widely used。
3. 6 condensers
Condensers for air-conditioning systems, typically installed in front of engine heaters, function as high temperature, high pressure gas refrigerant condensed into high temperature (50 ~55 °c), high pressure (1100 ~ 1400 kpa) liquid refrigerants from compressors。
Thermal exchange capacity of condensers should be the combination of thermal exchange capacity of evaporation containers and compressors. Condensers typically have a heat dispersion area twice as large as the evaporation unit, and the larger the heat is, the better the cooling effect. In order to ensure better cooling effects and improve refrigeration capacity, electrically controlled auxiliary fans are often installed in front of condensers, with high-speed and low-speed slots. When installing a condenser, the refrigerant that should be released from the compressor must enter at the upper entrance of the compressor and its export must be at the lower end, otherwise it may cause an increase in the pressure of the refrigeration system, which may condensate the condenser。
Automobile air-conditioning condensers usually have three types of structure: tube-forming, tape-banding and flat-streaming. The condenser is a heat exchanger whose materials may be steel, copper or aluminium. It is structured as a set of tubes with dispersors, which are designed to increase the heat area of the condensers and are supported by the tubes. Condensers are the hardest-to-place components in the air conditioning system, and inappropriate placement and cooling measures not only affect vehicle air conditioning performance and cause excessive condensation pressure, which creates a range of insecurity factors, but also adversely affects vehicle heat dispersion. Automobile air-conditioning condensers are mostly placed on the head or under the car, on the side, and car condensers are usually placed on the front。
3. 7 temperature switches
The ambient temperature switches consist mainly of catheters, film, electromagnetic ionator wires, springs and contact points. The function of the ambient temperature switch is to automatically cut the electromagnetic ionator when the external temperature is less than 5°c, to feel the ambient temperature through the cavity tube, to drive the switch frame around through a film, to increase the internal pressure of the cavity tube when the external temperature is high, to make the frame turn large, to cause the electrocution to close, to connect the electromagnetic ionosphere, and to operate the compressor, and, when the external temperature is reduced, to separate the contact point by pulling the spring, to cause the circuit to be broken, the compressor to stop working, the condensor to rotate, and to change the closed temperature of the contact point。
3. 8 liquid storage bottles
Since the supply of refrigerants is greater than the requirements of evaporation units during normal operation of car air conditioning, there is some storage of high pressure side liquid refrigerants. With seasonal variations, refrigerants in systems are generated to be stored on high pressure sides when parts of systems are not operated or overhauled or replaced to avoid refrigerant leakage。
The liquid dryer is installed between the condenser and the expansion valve. It typically consists of casings, filters, dry agents, glass-observing windows, extraction tubes, etc., as shown in figure 3-2-4。
Liquid dryers are used to store refrigerants, absorb water from refrigerants and filter impurities from refrigerants. When liquid refrigerants containing vapour enter the liquid dryer, the liquid and gas refrigerants are separated. Liquid refrigerants enter evaporation tanks through expansion valves, and excess refrigerants may be temporarily stored in storage tanks. Drying agents are used to absorb water in refrigerants and, as water is combined with refrigerants to produce acid or ice, dryers can prevent the apparatus from corrosive or block-off expansion valves. Filters are used to filter impurities in refrigerants and to guard against swelling valves。
There are observation windows on the liquid dryer that can be used to determine certain system failures. When the temperature is above 21°c and the engine starts, the air conditioner control switch moves to the coldest (max) position, and the winder moves to the top to observe the air bubble on the liquid window. If only a short bubble appears and then disappears, this means that the air conditioning system is working properly; if the bubble remains, it may be inadequate refrigerants or other malfunctions should be repaired in a timely manner。
Figure 3-2-4 liquid dryer structure
1-peep glass 2-filter 3-dry agent 4-eject tube 5-consolidated switch
Chapter iv structure and working principles of the b5 ac heating system in pasart
4. 1 general description of the air-conditioning heating system
Modern car air conditioning has evolved into an integrated cooling and heating system that not only cools, but also provides heat and ventilation, and is an air-conditioning system adapted to the year-round climate. And heat heating is one of the important functions of car air conditioning. Automobile air-conditioning heating systems are mechanisms for introducing fresh air from the outside of the vehicle into the heat exchange, absorbing the heat from one of these sources, thereby increasing the temperature of the air and bringing it into the vehicle。
Thermal sources used in car ac heating systems can be divided into heat water heating units, combustion heating units and combined heating units. The heating system using engine cooling water heat is called a hot water heating unit; the heating system with a specialized combustion unit is called an independent combustion heating unit; the heating system with engine cooling water is called an integrated preheating unit. Depending on the air cycle mode, three types of inner cycle, outer cycle and internal and external mixed cycle can be distinguished. Depending on the heat carrier, it can be divided into two main categories: water and heating。
4. 1. 1 role of air-conditioning heating systems
Automobile air-conditioning heating systems are mechanisms for introducing fresh air from the outside of the vehicle into the heat exchange, absorbing the heat from one of these sources, thereby increasing the temperature of the air and bringing it into the vehicle. The main functions of the car air-conditioning heating system are to adapt the air, together with the evaporation unit, to the comfort of the crew; to provide pure heating to the vehicle during cold winters, increasing the temperature of the air inside the vehicle; and to remove the fog or frost from the vehicle's windows when the fog or frost affects the driver's and passenger's vision and is detrimental to the safety of the vehicle, by blowing heat out or defrosting through heating devices to satisfy the driver's safe driving。
4. 1. 2 structure and working principles of air-conditioning heating systems
The heating units consist mainly of fresh air winders (v2), heat exchangers and central vents, footspace vents, wind vents for side window windows, frosting nozzles, etc。
Pasat b5 ahv: new and circular air locator locator locator controls the opening and closing of new air imports and recycle air imports, and air evaporating by fresh air drums enters the air conditioning and heating units, when heating, the temperature locator allows air to pass the heat exchanger, and when cooling, the temperature locator closes the access to the heat exchanger. The central vents are opened or closed to the central vents of frosts and air from the feet, as required. Foot air vents and defrost-defunct walkers open or close vents and defrosters as required。
Chapter 5 structure and operation of the b5 air-conditioning system in pasart
5. 1 overview of air conditioning control systems
In order for the car air-conditioning system to function and to maintain the comfortable conditions required in the vehicle, a range of control elements and reconciliation enforcement units are required in the vehicle air-conditioning system. Automobile air-conditioning systems have been developed from manual operations to semi-automated or fully automated controls. Many advanced auto air conditioners now use microcomputer controls, which are truly fully automated。
Automobile air conditioning systems require a full range of air temperature control, wind delivery control and refrigerant temperature control, pressure control, traffic control and associated circuits, controllers, wind delivery control devices, etc. At the same time, in order to protect the normal operation of the car air-conditioning system, various protection circuits are also required in special circumstances. The installation of air-conditioning systems in vehicles, in particular for non-independent air-conditioning systems, requires the consumption of power and power from the main engine, which affects the power and economy of the vehicle engine, thus affecting its operation. In order to ensure that the car's condition is not affected by air conditioning, it is also necessary to set up a vehicle condition control device。
5. 2 structure of air conditioning control systems
In order to ensure the proper operation of the ac system and to meet the requirements of the comfort conditions in the vehicle, ac is subject to a series of controls by the control system. Control functions of the control system include internal temperature control, engine load control and safety protection control。
In-vehicle temperature control: the control system controls the temperature of wind delivery, the volume of wind delivery and the direction of wind delivery to regulate the internal temperature of the vehicle
Engine load control: non-independent air conditioners are motor-driven and their operation affects engine load changes, which in turn affects vehicle mobility. Air-conditioning control systems should coordinate the operation of engines and air-conditioning。
Safety protection controls: when the air conditioning system is over-pressure or over-temperature, damage to the air conditioning system is caused, and therefore the control system should be able to perform security protection controls。
The pasat b5 control unit, which is mainly an air conditioner regulator, is installed on the dashboard. The fresh air blower switch button 4 is designed to manipulate the fresh air blower switch (e9) and, when the ac switch (e35) is connected, a combination of electrical resistors (n24) can be obtained through the wind blower; the temperature worklock lock control wing 3 is locked to control the temperature and manipulates the opening of the hot workgate, rotating from a left to the right the temperature from the cold to the heat. The air vents are allocated to the air vents, with four locations. Position 1 opens the central vent to the central vent and the vents to the frost and foot spaces are closed at a time when the vehicle is heating or cooling. Position 2 closes the central vent for the central vent and opens the foot vent for the vent for the frost and foot vent. Location 3 is the central vent and the central vent is closed and the frosting and foot vent is open to the frosting period. The center of position 4 is the center of the vent, the center of the vent, the center of the vent, the center of the vent, the center of the vent, the center of the vent, the center of the vent, the center of the vent, the center of the vent, the center of the vent, the center of the vent, and the center of the vent, the center of the vent, the center of the vent, the center of the vent, the center of the vent, the center of the vent, the center of the vent, the center of the vent, the center of the vent, and the air is the center of the vent。
