Car air conditioner - device and how it works. Malfunctions

With the onset of heat, many motorists begin to think about installing an air conditioner in their car. Owners of vehicles equipped with this system have additional troubles in diagnosing and maintaining an element of the climate system.

Although this device is mainly included in the heat, some use its hidden functions when the humidity level rises. More details about the use of the climate system in such conditions are described separately... Now let's dwell on the modifications of air conditioners, what are the options for those cars that are not equipped with these mechanisms from the factory. Let's also see what common problems the owners of cars equipped with car air conditioners face.

What is car air conditioner

First, let's briefly discuss what a car air conditioner is. This is a system that makes it possible to cool the air entering the car from the street. During operation, moisture is removed from the stream, making everyone in the car comfortable in the heat. If the climatic element is used in a cool but very humid time (heavy rain or fog), then the air conditioner dries up the flow, making it easier to heat the cabin with the stove.

A modern car is equipped with a model integrated into the ventilation and heating system. To select the desired mode, the driver just needs to turn on the unit and turn the switch to the cooling or heating position. For this reason, many beginners do not see the difference between the operation of the air conditioner in the car and the heating system.

A feature of such a system is that it uses not the electricity generated by the generator, but the resource of the internal combustion engine. In addition to the timing belt and generator, such an engine will also drive the compressor pulley.

The first air conditioning system, operating on the principle of a domestic air conditioner, was ordered as an option for luxury limousine cars. The ability to re-equip transport was provided by a New York company in 1933. However, the first production car, which received a factory complete set, rolled off the assembly line in the 39th year. It was a Packard model that had a small edition, and each piece was assembled by hand.

Installing an air conditioner in those years was a huge waste. So, the car mentioned above, in which there was a climate mechanism of this type, cost $ 274 more than the base model. By those standards, it was a third of the cost of a full-fledged car, for example, a Ford.

The disadvantages of this development were the dimensions of the installation (in some cars, the radiator, compressor and other elements occupied almost half of the trunk volume) and the lack of basic automation.

A modern car air conditioning system has the following device:

• Compressor connected to the motor. It is driven by a separate belt, and in some car models, the installation works from the same drive element (belt or chain) as other attachments;
• A radiator into which the heated refrigerant is supplied;
• An evaporative element, similar to a radiator, from which cool air is taken into the cabin;
• Fan mounted on the evaporator.

In addition to these main components and elements, sensors and regulators are installed in the system, which ensure the efficiency of the installation regardless of the conditions in which the car is found.

How a car air conditioner works

Today there are many modifications of air conditioners. To make the system more efficient, manufacturers add various small mechanisms and sensors to the system. Despite this, the cooling line will work according to the general principle. It is identical to the functioning of a domestic refrigeration unit.

Just like in the case of the refrigerator, the car air conditioner is represented by a sealed system that is filled with refrigerant. A special refrigeration oil is used to lubricate the moving parts. This liquid is not afraid of low temperatures.

A classic air conditioner will work as follows:

1. When the driver starts the engine, the compressor pulley begins to rotate with the unit. If the passenger compartment does not need to be cooled, the unit remains inactive.
2. As soon as the A / C button is pressed, the electromagnetic clutch is activated. It presses the compressor drive disc against the pulley. The installation starts working.
3. Inside the compressor, cool freon is strongly compressed. The temperature of the substance rises sharply.
4. A highly heated refrigerant enters the radiator cavity (also called a condenser). There, under the influence of cool air currents (either when driving a car, or when a fan is activated), the substance cools.
5. The fan is activated at the same time as the compressor is switched on. By default, it starts running at first speed. Depending on the parameters recorded by the system sensors, the impeller can rotate at different speeds.
6. The cooled substance is then circulated to the receiver. A filter element is installed there, which cleans the working medium from foreign particles that can block a thin section of the line.
7. The cooled freon leaves the radiator in a liquid state (it condenses in the condenser).
8. Then the liquid enters the thermostatic valve. This is a small damper that regulates the supply of freon. The substance is fed into an evaporator - a small radiator, near which a passenger compartment fan is installed.
9. In the evaporator, the physical properties of the refrigerant change dramatically - it again turns into a gaseous state or it evaporates (it boils, but at the same time it cools down strongly). If water had such properties, then it would turn into ice in this node. Since Freon does not take on a solid structure under such conditions, the evaporator can get very cold. The cold air is blown away by the fan through air vents located in the appropriate places in the passenger compartment.
10. After evaporation, the gaseous freon will enter the compressor cavity, where the medium is again strongly compressed. At this stage, the loop is closed.

The entire air conditioning system is divided into two parts. The tubes are thin between the compressor and the thermostatic valve. They have a positive temperature (some of them are even hot). This section is called the "pressure line".

The evaporator and the hose that goes to the compressor is called the "return line". In thick tubes, freon is under low pressure, and its temperature is always below zero - icy.

In the first sleeve, the refrigerant head can reach 15 atm. In the second, it does not exceed 2 atm. When the driver turns off the climate system, the pressure in the entire highway becomes the same - within 5 atm.

The design is equipped with various types of sensors that provide automatic on / off of the compressor. For example, one type of device is installed near the receiver. It activates different speeds of the radiator cooling fan. The second sensor, which monitors the cooling operation of the heat exchanger, is located on the condenser. It reacts to an increase in pressure in the discharge line and increases the fan power. This often happens when the car is in a traffic jam.

There are situations when the pressure in the system rises to such an extent that the line can burst. To prevent this, the air conditioner has a compressor shutdown sensor. Also, the evaporator temperature sensor is responsible for turning off the air conditioner engine. As soon as it drops to critical values, the device turns off.

Types of car air conditioners

All air conditioners for cars differ from each other in the type of control:

1. The manual option involves setting the temperature mode by the driver himself. In these climate systems, cooling depends on the speed of the vehicle and on the speed of the crankshaft. This type has a significant drawback - in order to set the desired position, the driver can be distracted from driving. However, this is the most budget model.
2. Automatic control type. Another name for the system is climate control. The driver in this version of the device only needs to turn on the system and set the desired interior temperature. Further, the automation independently regulates the strength of the cold air supply.
3. The combined system makes it possible to set either automatic or manual mode.

Piston compressor

In addition to the type of control, air conditioners also differ from each other with compressors:

1. Rotary drive;
2. Piston drive.

Most often, a rotary compressor is used in cars. Also, the system can use different sensors and chokes, thanks to which the system becomes more efficient and stable. When buying a new car, each client can choose the option that is ideally effective for his situation.

It is also worth mentioning separately that there are two main categories of air conditioners:

• Regular - the installation with which the vehicle is equipped at the plant;
• Portable - a stand-alone air conditioner that can be used in different cars, and sometimes even in small domestic spaces.

Portable Evaporative Air Conditioners

A portable mechanism of this type is not a complete air conditioner. Its peculiarity is that the structure is not filled with refrigerant. This is a portable device that has a fan and uses ice or cold water as a cooler (depending on the model). The substance is placed in an evaporator. These models work both as evaporators and as conventional fans.

In its simplest form, the structure will consist of a case with a fan and a water tank. A small heat exchanger is installed in the evaporator. It is represented by a synthetic cloth that resembles an air filter. The device works according to the following principle.

The evaporator tank is filled with water. The fan is connected to the cigarette lighter (some models are self-powered). The water from the reservoir will flow onto the surface of the synthetic heat exchanger. The air flow cools the surface.

The fan will take heat for the evaporator from the passenger compartment. The air temperature decreases due to the evaporation of cool moisture from the surface of the heat exchanger. Among the advantages of the device is the ability to slightly cool the air in the car, as well as the spaciousness of the structure (the device can be installed in any convenient place in the cabin). Another argument in favor of using such a device is that a mobile air conditioner is much easier to maintain and replace with an improved analogue. Also, it does not need the motor to work, of course, if the battery in the car is well charged.

However, such air conditioners have a significant disadvantage. Since water evaporates in the cabin, the humidity in it rises greatly. In addition to the discomfort in the form of condensation on the glass surface (it will appear the next morning), the presence of moisture in the cabin can contribute to fungal formations.

Compressor air conditioners from the cigarette lighter

Such mobile air conditioners deserve more attention. Their principle of operation is identical to the standard analogue. In their design, a compressor is installed, connected to a closed line filled with refrigerant.

Like a standard air conditioner, such devices generate heat from one part, and cold air blows on the other. The design is very similar to a regular air conditioner, only this is its reduced version. In a mobile unit, the compressor is powered by an individual electric motor, which is its main advantage. Its drive does not need to be connected to the engine, so that the power unit will not be subject to additional load.

The only caveat is that part of the line generates heat. If it is not removed from the passenger compartment, the air conditioner will run idle (both cool and heat itself). To alleviate this effect, the models are made flat and fitted into the hatch. True, if it is not provided by the manufacturer, the roof will require some alterations. It is also extremely important during installation to ensure the tightness of the installation site, because the roof will leak during rain.

Such air conditioners can also work from the car cigarette lighter, as well as evaporative modifications. The only drawback is that they are more powerful than those discussed above. So, for conventional devices, a current of 4A is sufficient, and this model requires from 7 to 12 amperes. If the device is turned on with the engine turned off, the battery will drain in a matter of minutes. For this reason, these air conditioners are mainly used on trucks, but they can also drain the battery in a few hours.

The efficiency of the autonomous air conditioner

Now let's discuss the key question: which air conditioner is better - regular or portable? The ideal option is an autonomous air conditioning unit. It can work independently of the power unit. The only thing is that they need a more powerful battery. With a standard battery, the device will have little or no power.

Analogs of the evaporative type are less demanding on electricity, so they can be used in any passenger car. True, the coolness of the evaporated water may not be enough for a comfortable trip. Fungus or mold are constant companions of moisture, which is retained in the air ducts of the car ventilation system.

All other portable so-called air conditioners are simply fans that are installed in a plastic case, and sometimes they can have elements that absorb moisture. Such devices do not cool the air, but simply provide improved circulation throughout the cabin. The quality of temperature reduction is much lower compared to standard cooling systems, but their cost is also lower.

Homemade options

If a standard compressor-type air conditioner requires a decent capital investment, then a home-made option can have a minimal cost. The simplest type can be made almost from improvised means. This will require:

• Plastic tray with lid;
• Fan (its dimensions depend on material capabilities, as well as on the required efficiency);
• Plastic pipe (you can take a sewer with a knee).

Two holes are made in the cover of the tray: one for blowing air (a fan will be connected to it), and the other for removing cool air (a plastic pipe is inserted into it).

The maximum efficiency of such a homemade unit is achieved using ice as a refrigerant. The disadvantage of such a product is that the ice in the container melts quickly. An improved option is a cooler bag, in which solid water does not melt so quickly. In any case, such an installation requires a lot of space in the cabin, and when the ice melts, water in the container may splash while the car is moving.

Compressor installations remain the most efficient today. They remove heat, which they themselves generate, and also cool the interior of the car qualitatively.

How to service car air conditioners

The very first thing a motorist should do to keep the air conditioner working properly is to keep the engine compartment clean. Particular attention should be paid to heat exchangers. They must be free from deposits and foreign objects (eg fluff or leaves). If this kind of pollution exists, the climate system may not work well.

Periodically, you should independently check the reliability of fixing the fasteners of the line and the actuators. When the car is running or the motor is running, vibrations should not form in the system. If such a problem is found, the clips must be tightened.

Usually, after winter operation of the car, the air conditioner does not need any special preparatory work for the summer mode. The only thing that can be done in spring is to start the car on a warm day and turn on the climate control. If any instability is found during the test run, you need to go to a car service for diagnostics as soon as possible.

Freon replacement is periodically required in the system. During the procedure, it is better not to stint and ask the wizard to diagnose. Especially if the car was bought by hand. Sometimes it happens that the owner of the vehicle refused to diagnose, but with the new refrigerant he did not have time to leave the service station gate. Checking the status of the system is not so expensive to save money on it.

What are the breakdowns

As for mechanical damage, modern air conditioners are protected against bursting as a result of excessive pressure build-up. To prevent such malfunctions, there are special sensors. Otherwise, only the compressor and the fan are subject to mechanical damage.

If a freon leak is detected, then the first element in which it can form is a capacitor. The reason is that this element is installed in front of the main radiator. When the car is driving, the front parts can be hit by pebbles and bugs. In winter, it gets dirt and chemical reagents, which are sprinkled on the road.

In the process of corrosion, as well as constant vibrations, microcracks can form. As soon as the pressure in the line rises, the problem area will leak.

Here are some more breakdowns that may occur during the operation of the air conditioner:

• Constant noise from the engine compartment, whether the climate system is on or not. The reason for this problem is the failure of the pulley bearing. It is better to fix this problem at a car service. There, at the same time, you can diagnose the entire system in order to prevent other breakdowns.
• When the air conditioner turns on, a constant noise is heard from under the hood. This is a symptom of a compressor breakdown. Due to frequent work and low-quality parts, backlash may form in the structure. By contacting a workshop as soon as the first signs of unstable operation appear, you can avoid costly repairs.

Conclusion

So, as you can see, air conditioning in a modern car is an integral element of the comfort system. Its serviceability will affect not only the general impressions of a long trip, but also the well-being of the driver and passengers. If the air conditioning unit is serviced on time, it will function properly for a long period.

Additionally, watch a video about the physical laws of the car air conditioner:

Car air conditioner in summer and winter. How it works

Questions and answers:

How to properly use the air conditioner in a car? In the summer, before turning on the air conditioner, ventilate the interior, do not set a low temperature, use the internal circulation for quick cooling.

How does an air conditioning compressor work in a car? On the same principle as a refrigerator compressor. It compresses the refrigerant, increasing its temperature, and directs it to the evaporator, which is cooled down to negative temperatures.

What is the auto mode in the air conditioner? This is an automatic cooling mode. The system automatically adjusts the optimal cooling and fan intensity. The driver only needs to select the desired temperature.