Today, many people have air conditioners in their cars. But few people thought about how they work. For car enthusiasts, this is just a button on the dashboard, which on a hot day gives coolness and freshness. Let's see the device and the principle of operation
Story
The very first climate systems for cars appeared before the Second World War. This option cost as much as a third of the car. In our country, or rather in the domestic auto industry, climate systems began to be installed at AvtoVAZ much later.
In 1933, in the United States, these devices were considered an integral part of living quarters. In 1936, engineers began developing systems for various vehicles. The first air conditioning units appeared in road trains for passengers. automobile was the same as in refrigerators. He has not changed today.
The most which was completed with such a comfortable novelty - Packard. But the installation was quite expensive - for $ 700 you could safely buy a new car. Installation cost $274 - one-third of the cost. Among the inconveniences of this first model stood out the large volume of the system. The installation occupied half the free space in the trunk, and there was no automatic control yet. These devices did not receive good reviews and popularity. Their release has been discontinued. In 1941, they returned to this topic again - it was an American Cadillac.
The war began and all development had to be stopped. 
It was possible to resume work only after the war. In 1954, engineers revolutionized the manufacture of these auto climate control systems. So, on models of the Nach-Kelvinator brand, they began to mount a real climate control, consisting of ventilation and heating. The system also included air conditioning and a heater. This climate was much smaller and was placed under the hood. These devices have become more popular, and the demand for them is constantly growing. The principle of operation of an automobile air conditioner has not changed since then.
In the early 90s in the States, almost all cars that rolled off the assembly line were equipped with air cooling systems. In our country, such options were placed only on cars of government members. The first domestic air conditioner was installed on the domestic ZIL-111. In the 60s, some primitive models were installed on trucks. And only in 1976, by decree of the government, harvesters, trucks, dump trucks began to be equipped with these systems.
How does a car air conditioner work?
Speaking about car air conditioners, you need to understand that this is a whole system. It consists of several main components, like many other devices in the car. We will briefly go through all the details and find out the device of the air conditioner, the principle of operation, and the features of operation.
Compressor
This device is the heart of the entire air conditioning system. Its function is to pump refrigerant through all lines and pipelines. The device draws freon vapor from the evaporator and sends the refrigerant to the condenser. On many modern systems, the compressor is the only moving mechanism.
The compressor is the only unit that allows you to separate the high and low pressure circuits. 
Experts call the high side - the discharge side, and the low side - the suction side. Many modern compressors are able to separate pressure zones thanks to a special reed valve.
Car air conditioner compressor: working principle
So, this is the main node of the system. It is necessary to compress the refrigerant in the gaseous state, as well as to ensure the processes of circulation of the refrigerant through the system. There are about 40 types of these parts. But today only rotary-vane and piston devices are common and popular.
The compressor is powered by the car's crankshaft drive belt. 
At the moment when the refrigerant is sucked into the unit, it is at almost atmospheric pressure. After freon gets inside the device, the drive belt drives a pump that compresses the gas and sends it to the condenser. The process of gas compression is accompanied by strong heating of the refrigerant. It should be noted that the device does not function with freon in liquid form. If liquid enters the compressor cavity, this leads to severe wear.
Electromagnetic clutch
Now the principle of operation of the air conditioner is at least a little clear. The device is started using a drive belt from the crankshaft. But between them is installed a pulley of an electromagnetic clutch. It can disconnect the compressor and drive pulley when needed.
In older models, a solenoid was used as an electromagnetic clutch, which was combined with a drive pulley. 
Today this clutch does not move. The solenoid can be found behind the compressor drive pulley. The pressure plate is located in front of the pulley.
It works as follows - the motorist presses the system power button, as a result, the solenoid receives power. Then a magnetic field appears, which presses the pressure plate against the pulley. It must be remembered that the air conditioner can take from 1.5 to 15 liters. With. engine power.
Condenser
To truly understand how an air conditioner works in a car, you need to fully understand each component of the system. The condenser is another important device. You can find it in front of the engine radiator.
The refrigerant enters this unit in liquid form from the compressor. 
After flowing through the winding pipes of this node, the liquid is cooled and sent further in a circle.
This part is used to cool freon. These parts are usually made from aluminium. They break very often, as they are prone to corrosion.
Receiver dryer
Before the refrigerant gets further, it must first pass through this device. After the condenser, the principle of operation of an automobile air conditioner provides for a special reservoir. Liquid will pass through it. In the tank you can find special granules that attract water.
In this receiver, excess fluid that managed to get into the system is completely removed. If water particles remain, they turn into ice. This may damage the device. Also, various debris can settle in the receiver.
Expansion tube or expansion valve
At this stage, the principle of operation of an automobile air conditioner changes from high pressure to low pressure. If you touch this part, you can feel different temperatures in the lines - from hot to cold.
Freon in liquid form under a sufficiently high pressure is supplied to the thermal expansion valve from the dryer through a special valve. This valve allows freon to return to a gaseous state again. This expansion reduces the pressure. The gas then enters the evaporator.
This valve contains a special pressure sensor, and also regulates the flow of freon so that the entire operation of the system is more stable. There are moving parts in the valve device. They wear out quite quickly, and for the quality of the air conditioner, they need to be changed from time to time.
Evaporator
When you start a car air conditioner, the principle of its operation is approximately clear. 
But in order to enjoy cold, pleasant and fresh air in the cabin, one more detail is needed.
The evaporator is the place in the system structure where all the magic happens. While all other components can be found under the hood, the evaporator is located in the passenger compartment. It is located slightly above the legs on the passenger side. This part is somewhat reminiscent of a radiator. There are also coils, tubes and fins. But the purpose of this design is heat dissipation.
Freon enters the evaporator in gaseous form. It is sufficiently chilled - its temperature tends to 0 degrees. The refrigerant cannot freeze at this temperature - its freezing temperature is lower. There is so much warm air in the cabin that the freon in the evaporator boils away. The fan blows through the evaporator in the cabin. The air passing through the almost ice-cold radiator gives pleasure.
Further, after gaseous freon passes through the evaporator, it will again enter the compressor, where it will become liquid under pressure and the cycle will repeat again. This is the principle of operation and design of the air conditioner.
Condensate
During the operation of car air conditioners, many noticed how water drips from under the bottom. Sometimes it leaks a lot, so much that after 10 minutes of inactivity, small streams form.
The evaporator is to blame for this, which, being in a cold state, draws all the moisture from the air that is there. This very moisture condenses like morning dew and then exits through special channels.
Electronics
A modern automobile and the principles of its operation are controlled by a large number of sensors. They are designed to adjust the functioning of various important components of the device at various stages. So, for example, if you are standing in a traffic jam, then the pressure in the high-pressure lines can reach critical levels. Therefore, thanks to the sensors, the compressor is turned off, and the tubes do not burst.
How to use car air conditioner?
Experts recommend even on the hottest day to start the air conditioning only after the engine has worked a little. You also need to turn off the engine after the air conditioner is turned off. This will significantly increase the resource.
In winter, when there is no need to cool the air in the cabin, it is recommended to start the climate system about once a month. Due to the fact that it does not work, various freon leaks may occur.
Common Problems
If you notice that your car air conditioner, the principle of operation of which we have just considered, has become worse in cooling the interior, this can say a lot.
For example, a fan is considered a frequent breakdown. It can simply fail, and as a result, the interior will not be cooled and blown enough.
During operation, the level of freon decreases naturally. In modern car brands, manufacturers have provided a special viewing window. Through it, you can monitor the condition and level of the refrigerant. So, when the system is running, there should be no white foam or air bubbles in this eye. Also, you can always evaluate the efficiency of your device if you touch the tubes coming out of the condenser. They should be literally ice cold.
Another popular problem is the smell, often very unpleasant. The reason is that hordes of various harmful bacteria accumulate on the evaporator. To get rid of this scourge, it is enough to simply clean the part from time to time with an antibacterial agent.
Leaks also happen regularly. To detect them, you can use special electronic devices to find leaks or try ultraviolet technology.
So, this equipment is very simply arranged, which every day gives comfort when driving. There is nothing complicated in the work, and with proper maintenance and proper operation, the air conditioner will please its owner for a very long time.
