How the engine cooling system works. Car engine cooling system Cooling engine

»Car engine cooling system, principle of operation, malfunction

The automotive engine cooling system is required to periodically check. Many significant car malfunctions cause engine overheating. The temperature of the combed fuel-air mixture reaches several thousand degrees. Accordingly, a large amount of heat is formed, which is required to be left, in order not to overheat the motor, which can lead to serious problems.

Engine overheating problems

Inefficient cooling system can lead to exceeding operating temperature Pistons, decrease thermal clearance Between the piston and the walls of the cylinder, right up to zero. It causes the housing of the cylinder wall piston, the formation of scratches, scratches. Also when overheated motor oil Loses lubricating properties, the oil film is broken. The engine may be swamped because of this.

Overheating of the cooling system and the engine is accompanied by different due to the various materials by the expansion of the GBC, the block and bolts of the mount, which leads to the destruction of the installation surface of the head, pulling the bolts, cracking the valves. It is clear that after such changes, the engine is difficult, and sometimes it is impossible.

Engine cooling fluids

A working cooling system should not allow overheating, but the use of high-quality cooling fluid is required for the normal functioning of the system. Non-freezing purposes low temperatures technical fluids called antifreeze (from English. Antifreeze). Today, antifreezes are made, as a rule, based on monoethylene glycol, which is a thick liquid with a boiling point of about 200 ° C.

The coolant problem is not only the cooling of the motor, but also heat transfer for the heating of the cabin, heating the fuel in winter. Car coolant should meet the following requirements:

• do not freeze in the entire area of \u200b\u200bengine operating temperatures;
• have high heat capacity and thermal conductivity;
• do not form a foam;
• do not eat plastic and rubber pipes;
• do not damage seals;
• lubricate, protect against corrosion parts of the cooling system and engine;
• do not postpone the scale and other deposits of various types on the inner walls of the working surface of the cooling system

It is customary to distinguish the concepts of Tosol and Antifreeze. It is believed that Tosol is a finished product, and antifreeze is concentrate. Although, of course, according to the composition, this is the same, just with different names.

Automotive antifreeze are painted into noticeable, bright colors:

• green,
• orange, or shades of red
• blue (blue),
• turquoise

It is done for the sake of security, because antifreeze is very poisonous. As the liquid is used, it loses the necessary properties - gradually lubricating and anti-corrosion parameters are gradually lost, the tendency to the formation of foam increases.

Important: The life of antifreezes is within 2-7 years.

After the car of the car, together with the engine, starts its rotation of the cooling system pump (also called pump, water pump) Unless of course electronic connection Pump. In rotation, the pump is given by the belt of the gas distribution mechanism (TRM) or with a belt hinged equipment - It depends on the design of the engine of a particular model. The impeller of the water pump, rotating, pumps the coolant through the system. To quickly access the operating temperature in the car cooling system, a small contour is provided, that is, the liquid circulates only inside the engine, the thermostat is closed, the antifreeze is not supplied to the radiator.

As soon as the engine warms up to a certain temperature, the thermostat opens, passing Tosol or antifreeze to the large contour of the cooling system. The liquid passes through the radiator where it is cooled. The radiator is cooled by outer air, freely passing through the radiator grille, or is enforced by a fan. After cooling in the radiator, the antifreeze is supplied to the engine cooling system, takes part of its heat and is sent again big circle.

The radiator is set to power on the fan, which when a certain temperature is reached, includes a forced blowing or changes the fan speed. When the rotation speed changes, the amount of air carrier passing through cells changes, respectively, the efficiency of the fluid cooling is adjustable. As the fluid cooling in the radiator, the fan turns off. If Tosol becomes colder than the response value, the large outline overlaps, - the circulation occurs in a small circle.

Some cooling systems use several temperature sensors, the location of the sensors:

• on the cooling system radiator,
• on the head of the cylinder block,
• directly on the thermostat housing.

Such a scheme of work is basic, but manufacturers constantly improve the cooling systems. In some machines, there are no fan power sensors, which is launched by a signal from the motor control unit depending on the temperature sensor readings. Thermostats can also be controlled by the "brains" of the motor, opening and switching contours is not automatically, but according to the control signal. In some models on the pipes leading to the heater, electromagnetic valves are installed, regulating the feed of the coolant into the stove radiator. If malfunction, these valves may cause cooling system problems.

One of the improvements of the cooling system is an electronic adjustable pump, more precisely the pump drive, which, depending on the engine temperature, connects the pump or turns off it, thereby contributes to more efficient thermal regulation and rapidly warming the car cooling system.

Diagnostics of cooling systems

Engine overheating - This is such a mode of operation, which is due to the boiling of the coolant. However, the problem is not only overheating. Operation of the motor at a constantly reduced temperature is also harmful, as the operating temperature should be maintained at a certain level. Cold Engine Consumes more fuel, it does not work with better efficiency, susceptible to high loads due to increased viscosity of the lubricant system.

Terms of thermostat, fan, thermostat and sensors violates the proper functioning of the cooling system. If the signs of the temperature of the temperature regime are detected on time and the emergence of fatal faults did not occur, then the repair is likely to be too long and expensive. Therefore, all experts are advised to monitor the temperature modes of the motor.

Diagnosis of problems and faults should be started on a cold engine. First you need to check the correctness of the joint and tubes, the assembly of other elements of the cooling system, especially if the car was repaired shortly before the problem occurs. Perhaps it is ridiculous, however, many examples are known when cooling does not work correctly due to assembly errors.

Some of these cases:

• after the bulkhead of the motor, the crankcase ventilation hose is connected to an expansion tank of the coolant;
• the cooling fan is installed, due to the irregular position of the blades of which the air is directed not in the direction;
• the blades of the fan impeller are freely rotated on the shaft;
• sensor or fan connectors are oxidized, rolled or damaged.

It will also be useful to conduct an external inspection of the radiator, it may be dirty, honeycomb is clogged. Sometimes there may be a negative impact of the engine, blocking the air from the bottom. A small accident that only led to the breakdown of the bumper can lead to overheating - there are special guides in the bumper, which passes the air to the engine ( VW Passat B5.).

After visual inspection Cooling systems need to check the level of antifreeze, the serviceability of the carrier tube valves or the tank, the tightness of the hoses and nozzles. It makes sense to decide what is flooded in the system - antifreeze or just water.

If the first steps helped calculate any malfunctions of the engine cooling system, they must be eliminated or taken into account when "Diagnosis" is set. Pulling fluid, you need to not forget that not in every car you can simply add antifreeze, and that's it. For example, some BMW at the top of the coolant should include ignition, and adjust the stove to maximize, in order for the electromagnetic heater valves.

If the air suspicion appears in the cooling system, it is necessary to unscrew special corks intended for air intake. They arrange, as a rule, at the highest point of the system. If there is a car expansion tankYou can check whether the liquid circulates. If with a systematic warming of the engine inside the interior of the heater ducts, cold air enters, this is the first sign of the air bubble in the system.

If the thermostat is obviously correct, after heating up the radiator, its lower pipe and the upper should have about the same temperature. A large difference in the temperatures of these pipes indicates poor circulation of antifreeze through the radiator.

After a certain period of time after opening the thermostat, as the response temperature achieves, the radiator cooling fan must turn on. If the system does not contain an electric fan, check the electromagnetic clutch closure sensor or the functioning of the viscous coupling. A sign of the malfunction of the viscous clutch can be considered the possibility of stopping and hold the fan with hand. Be sure to be careful! Stop trying to exercise with a soft object, to eliminate the likelihood of hand injury or impeller damage. The airflow in the correct case should be directed to the engine.

Cooling system pressure The car increases in proportion to the engine warming and smoothly falls as cooling it. If the upper nozzle suitable for the radiator is inflated from increasing the frequency of rotation of the engine, it makes sense to make sure that the system does not fall into the system of gases from the motor. It happens if gasket GBC. He struck between the cooling channel and the cylinder or when damaged the head of the block itself. One of the signs of this problem is the oil filler in the expansion tank. Also, bubbles appearing in antifreeze in the engine during operation.

Examples of how incorrectly operating cooling system led to serious, up to the replacement of the engine, problems for the owner, set. The main output should be made one thing - there are no trifles and unimportant faults in the car. You need to notice all changes, analyze them, make the right conclusions. If the owner of the car does not understand this, one should regularly serve the car from good professionals.

Replacing coolant, antifreeze or toosol
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The engine cooling system is used to maintain the normal thermal mode of operation of the engines by intensive heat removal from the hot engine parts and transferring this heat to the environment.

The vehicle velocity consists of a part of the heat engine released in the cylinders, which does not turn into work and not worn with exhaust gases, and from the heat of the work of friction occurring when the engine details move.

Most of the heat is discharged into the environment of the cooling system, a smaller part is a lubrication system and directly from the outer surfaces of the engine.

Forced heat dissipation is necessary because at high gases in the engine cylinders (during the combustion process 1800-2400 ° C, the average temperature of the gases for the working cycle at full load 600-1000 ° C) the natural return of heat into the environment turns out to be insufficient.

Violation of the proper heat removal causes a deterioration in the lubricant of rubbing surfaces, burning oil and overheating engine parts. The latter leads to a sharp drop in the strength of the material of the details and even their burning (for example, exhaust valves). With a strong overheating of the engine, normal gaps between its parts are violated, which usually leads to elevated wear, jamming and even breakdown. The engine overheating is harmful and because it causes a decrease in the filling coefficient, and in gasoline engines, in addition, detonation combustion and self-ignition of the working mixture.

Excessive engine cooling is also undesirable, since it entails the condensation of fuel particles on the walls of cylinders, deterioration of the mixture formation and flammability of the working mixture, reducing the speed of its combustion and, as a result, reducing the power and engineering engineering.

Classification of cooling systems

In automotive and tractor engines, depending on the working fluid, systems are used liquid and air cooling. The greatest distribution was liquid cooling.

With liquid cooling circulating in the engine cooling system, the liquid perceives heat from the walls of cylinders and combustion chambers and then transfers it warm with the help of a radiator of the environment.

On the principle of heat removal in the environment of the cooling system can be closed and unclosed (flowing).

Liquid cooling systems of autotractor engines have a closed cooling system, i.e. the constant amount of fluid circulates in the system. In the flowing system of cooling, the heated fluid after passing through it is ejected into the environment, and the new is closed to feed into the engine. The use of such systems is limited by ship and stationary engines.

Air cooling systems are unclipped. Cooling air after passing through the cooling system is displayed in the environment.

Classification of cooling systems is shown in Fig. 3.1.

By a method for carrying out the circulation of the fluid, the cooling system can be:

forced, in which the circulation is provided by a special pump located on the engine (or in the power unit), or pressure under which the fluid is supplied to power installation from the external environment;

thermophonein which the fluid circulation occurs due to the difference in the gravitational forces arising from the different density of the liquid heated near the surfaces of the engine parts and cooled in the cooler;

combinedin which the most heated parts (cylinder heads, pistons) are cooled forced, and cylinder blocks - by the thermophone principle .

Fig. 3.1. Classification of cooling systems

Systems liquid cooling Can be open and closed.

Open systems - Systems communicating with the environment using a steam tube.

Most automotive and tractor engines are currently used closed systems cooling, i.e. systems, separated from the environment installed in the radiator plug by a steam valve.

The pressure and, respectively, the permissible temperature of the coolant (100-105 ° C) in these systems are higher than in open systems (90-95 ° C), as a result of which the difference between fluid temperatures and the radiator separated through the radiator and heat transfer increases. This allows you to reduce the size of the radiator and the power cost per fan drive and the water pump. In closed systems, there is almost no evaporation of water through the steaming nozzle and boiling it when the engine is operating under high conditions.

Liquid cooling system

In fig. 3.2 shows a diagram of a liquid cooling system with forced circulation of coolant.

Cylinder Block Cooling Shirt 2 And block heads 3, the radiator and nozzles through the bay neck are filled with coolant. The liquid ishes the walls of cylinders and combustion chambers of the operating engine and, heating, cools them. Centrifugal pump 1 The liquid inserts into the shirt of the cylinder block, from which the heated liquid enters the shirt of the block head and then the upper nozzle is supplanted into the radiator. The liquid cooled in the radiator on the lower nozzle returns to the pump.

Fig. 3.2. Liquid cooling scheme

The circulation of the fluid depending on the thermal state of the engine varies using the thermostat 4. At coolant temperature below 70-75 ° C, the main thermostat valve is closed. In this case, the fluid does not enter the radiator 5 , and circulates on a small contour through the nozzle 6, which contributes to the rapid engine warming to the optimal thermal regime. When heating the thermostat thermostatic element to 70-75 ° C, the main thermostat valve begins to open and pass water into the radiator where it is cooled. Full thermostat opens at 83-90 ° C. From this point on, the water circulates along the radiator, i.e. the large, contour. The temperature of the engine is also adjustable using swivels, by changing the air flow created by the fan 7 and passing through the radiator.

IN last years The most efficient and rational way to automatically regulate the temperature mode of the engine is the change in the performance of the fan itself.

Elements of the liquid system

Thermostatdesigned to ensure automatic control of the coolant temperature during engine operation.

To quickly warm up the engine when it starts, the thermostat is installed in the outlet of the shirt shirt of the cylinder block head. It supports the desired temperature of the cooling fluid by changing the intensity of its circulation through the radiator.

In fig. 3.3 Presents the thermostat of the bellows type. It consists of a housing 2, Corrugated Cylinder (Sylphon), Valve 1 and rod connecting the flap with valve . The bellows are made of fine brass and filled with a quick-sleeping fluid (for example, ether or a mixture of ethyl alcohol and water). Located in the windows thermostat housing 3 Depending on the temperature of the coolant, may or remain open, or being closed valves .

At coolant temperature, washing the bellows, below 70 ° C valve 1 closed and windows 3 Open. As a result, the coolant in the radiator does not come, and circulates inside the engine shirt. With an increase in the temperature of the coolant above 70 ° C, the bellows under pressure of vapors evaporating in it fluids is lengthened and starts opening the valve 1 and gradually cover windows with valves 3. At coolant temperature above 80-85 ° C valve 1 Fully opens, the windows are completely closed, as a result of which the entire cooling fluid circulates through the radiator. Currently this type Thermostats are very rare.

Fig. 3.3. Thermostat of the bellows type

Now in engines install thermostats in which the flap 1 Opened when the solid filler is expanded - Cerezina (Fig. 3.4). This substance is expanding with increasing temperature and opens the flap 1 , ensuring the flow of coolant into the radiator.

Fig. 3.4. Thermostat with solid filler

Radiator It is a heat dissipating device designed to transmit heat coolant with surrounding air.

Radiators of automotive and tractor engines consist of the upper and lower tanks interconnected with a large number of thin tubes.

To enhance the transfer of heat from the coolant air, the fluid flow in the radiator is directed through a number of narrow tubes or channels blocked by air. Radiators are manufactured from materials well conductive and giving heat (brass and aluminum).

Depending on the design of the cooling lattice, radiators are divided into tubular, plate and cellular.

Currently, the greatest distribution received tubular radiators. The cooling grille of such radiators (Fig. 3.5a) consists of vertical tubes of oval or round-section, passing through a series of thin horizontal plates and soldered to the upper and lower radiator tanks. The presence of plates improves heat transfer and increases the rigidity of the radiator. Tubes of oval (flat) section is preferable, since with the same cross section of the jet, the cooling surface is greater than the surface of the cooling of round tubes; In addition, when the water freezing in the radiator is freezing, flat tubes do not burst, but only change the cross-sectional shape.

Fig. 3.5. Radiators

IN plate radiators The cooling grille (Fig. 3.5b) is designed so that the coolant circulates in space , Formed by each pair of soldered among themselves along the edges of the plates. The upper and lower ends of the plates, in addition, are embedded into the holes of the upper and lower tanks of the radiator. Air, cooling radiator, is asked to a fan through the passages between the soldered plates. To increase the cooling surface, the plate is usually carried as wavy. Plastic radiators have a large cooling surface than tubular, but due to a number of shortcomings (rapid pollution, a large number of soldered seams, the need for more thorough care) are applied relatively rarely.

Cellular radiator Refers to radiators with air tubes (Fig. 3.5B). In the honeycomb grille, the air passes along the horizontal, circular cross section of tubes, washed outside with water or coolant. To make a possible spike of the ends of the tubes, the edges of them are ruined so that in the section they have the form of the right hexagon.

The advantage of cellular radiators is large than in the radiators of other types, the cooling surface. Because of a number of shortcomings, most of which are the same as in lamellar radiators, cellular radiators are currently extremely rare.

In the tube plugging of the radiator, a steam valve is installed 2 and air valve 1 which serve to maintain pressure at specified limits (Fig. 3.6).

Fig. 3.6. Cork radiator

Water pump Provides circulation of coolant in the system. As a rule, in cooling systems, low-sized single-stage low pressure centrifugal pumps with a capacity of up to 13 m 3 / h, creating pressure 0.05-0.2 MPa. Such pumps are constructively simple, reliable and provide high performance (Fig. 3.7).

The housing and the impeller pumps are cast from magnesium, aluminum alloys, an impeller, in addition, from plastics. In water pumps of automotive engines, semi-closed impellers are used, i.e., impeller with one disc.

The impellers of centrifugal water pumps are often mounted on one roller with a fan. In this case, the pump is installed in the upper front of the engine, it is driven by a crankshaft using a clinorem.

Fig. 3.7. Water pump

Belt transmission can also be used when installing a centrifugal pump separately from the fan. In some engines of trucks and tractors, the water pump drive is carried out from crankshaft gear transmission. The centrifugal water pump shaft is usually installed on rolling bearings and supplied to the working surface to seal with simple or self-regulating seals.

Fanin liquid cooling systems, set to create an artificial flow of air passing through the radiator. Automotive and tractor engines fans are divided into two types: a) with stamped from sheet steel blades attached to the hub; b) with blades that cast for one whole with the hub.

The number of fan blades varies within four - six. Increasing the number of blades above six is \u200b\u200binappropriate, since the performance of the fan is increasing extremely slightly. Fan blades can be placed flat and convex.

Engine cooling system internal combustion Designed to remove unnecessary heat from parts and engine nodes. In fact, this system is harmful to your pocket. Approximately one third of the warmth obtained from the combustion of precious fuel is necessary to disperse in the environment. But such is the device modern DVS. Ideal would be an engine that can work without removal of warmth into the environment, but all it is turned into useful work. But the materials used in modern engine building, such temperatures will not stand. Therefore, at least two main, basic parts of the engine - the cylinder block and the block head - it has to be additionally cooled. At the dawn of the automotive industry, two cooling systems were competed for a long time: liquid and air. But the air cooling system gradually passed its position and is now applied, mainly on very small engines Motorports and generator sets of low power. Therefore, we consider in more detail the liquid cooling system.

Cooling system device

The cooling system of a modern automotive engine includes a motor cooling shirt, a coolant pump, a thermostat, connecting hoses and a radiator with a fan. The heat exchanger of the heater is connected to the cooling system. In some engines, the coolant is also used for heating the throttle node. Also, engines with the supervision system occurs in the flow of coolant into liquid-air intercoolers or the turbocharger itself to reduce its temperature.

The cooling system is quite simple. After starting the cold engine, the coolant begins with a pump to circulate for a small circle. It passes through the cooling shirt of the block and the engine cylinders head and returns to the pump through the bypass (bypass) nozzles. In parallel (on the overwhelming majority modern cars) Liquid is constantly circulating through the heater heat exchanger. As soon as the temperature reaches a given value, usually about 80-90 ° C, the thermostat begins to open. Its primary valve directs the flow into the radiator, where the liquid is cooled by the oncoming air flow. If the air blowing is not enough, the cooling system fan is enhanced, in most cases having an electric drive. The fluid movement in all other nodes of the cooling system continues. Often the exception is the bypass channel, but it is not closed on all cars.

The schemes of cooling systems in recent years have become very similar to one another. But there are two fundamental differences. The first is the location of the thermostat before and after the radiator (along the movement of the fluid). The second difference is the use of a circulating expansion tank under pressure, or a tank without a pressure, which is a simple backup volume.

On the example of three cooling system schemes, we will show the difference between these options.

Components

Shirt head and cylinder block There are channels cast in an aluminum or cast iron product. Channels are sealed, and the joint and cylinder heads are sealed with a gasket.

Cooling fluid pump paddle, centrifugal type. Is driven either timing beltor a belt drive auxiliary units.

Thermostatit is an automatic valve that is triggered when a certain temperature is reached. It opens, and part of the hot liquid is reset into the radiator, where it cools. Recently began to apply electronic control that simple device. Coolant has begun to warm up a special tenan for an earlier discovery of the thermostat in case of need.

Replacing fluid and flushing

If I did not have to replace any node in the cooling system earlier, the instructions recommend changing antifreeze at least 5-10 years. If you did not have to add water from the canister into the system, and even worse - from the roadside dials, then when replacing the liquid, the system can not be flushed.

But if the car has seen a lot in its century, then when replacing the liquid it is useful to produce. Outping in several places the system can be ringed with a jet of water from the hose carefully. Either just merge old liquid and pour clean, boiled water. Run the engine and warm up to operating temperature. After the system cools down, so as not to burn, drain the water. Then blow the system and fill the fresh antifreeze.

Washing the cooling system is usually covered in two cases: when the engine overheats it (it is primarily in the summer) and when it ceases to warm the stove in the winter. In the first case, the cause lies in the dirt outside and clogged from the inside tubes of the radiator. In the second, the problem is that they have been hammered by the deposits of the heater radiator tube. Therefore, with a planned change of fluid and when replacing the cooling system components, do not miss the capabilities to rinse all nodes.

Tell us how the cooling system faults faced you. And I wish you a hot heater in winter and good cooling in summer.

When combustion of fuel inside the cylinder, the temperature of the gases rises to 2000 ° C. Heat is consumed by mechanical workPartly carved with exhaust gases is spent on radiating and heating engine parts. If it is not cooling it, it loses its power (the filling of the cylinders of the working mixture is deteriorating, the premature self-ignition of the mixture occurs, etc.), the wear of parts increase (oil in the gaps) and the probability of the breakage of them increases as a result of a decrease mechanical properties Materials.

If the engine is percooled, the amount of heat transferred to work is reduced, the fuel condenses on the cold walls of the cylinders, flows into the crankcase (oil tank) and dilutes the lubricant, which also leads to an increase in the wear of rubbing parts and reduce the engine power. Thus, maintaining a certain thermal engine mode is an important and obligatory business. So everyone car engines have a cooling system.

There are liquid I. aerial systems cooling. Liquid cooling systems have become more distribution, since with their help more favorable thermal mode is created for engine parts. The ability to manufacture engine parts from relatively inexpensive materials. Such engines, when working, create less noise due to the presence of double walls (shirts) and coolant layer.

The cooling system is liquid, closed type, with forced circulation. The tightness of the system is provided with intake and exhaust valves in the plug of the expansion tank. The outlet valve supports increased (compared to atmospheric) pressure in the system on a hot engine (due to this, the boiling point of the liquid becomes higher, steam losses decrease). It opens at a pressure of 1.1-1.5 kgf / cm2. The intake valve opens with a decrease in pressure in the system relative to atmospheric at 0.03-0.13 kgf / cm2 (on the cooling engine).

The heat mode of the engine is maintained by a thermostat and radiator electric fan. The latter turns on the sensor screwed into the left radiator tank (on the VAZ-2110 motor) or through the relay by signal electronic block Engine control (on VAZ-2111, -2112 engines). The sensor contacts are closed at a temperature of 99 ± 2 ° C, and opened at a temperature of 94 ± 2 ° C.

To control the temperature of the coolant into the engine cylinder head, the sensor is screwed to the temperature pointer to dashboard. In the exhaust pipe of injection engines (VAZ-2111, -2112) installed additional sensor Temperatures issuing information for the electronic engine control unit.

The coolant pump - paddle, centrifugal type is driven by the crankshaft pulley with a gear distribution mechanism with a gear distribution belt. Pump housing - aluminum. Roller rotates in a double row bearing with a "lifelong" reserve plastic lubricant. The outer ring of the bearing will stop the screw. On the front end of the roller, a toothed pulley is pressed, on the rear - impeller. A stubborn ring from a graphite-containing composition is pressed to the end of the impeller, which is the gland. When the pump is output, it is recommended to replace it assembly.

The redistribution of fluid flow controls the thermostat. On the cold engine, the overlap valve of the thermostat overlaps the nozzle leading to the radiator and the liquid circulates only for a small circle (through the bypass heat pipe), bypassing the radiator. On the VAZ-2110 engine, the small circle includes a heater radiator, an intake manifold, a carburetor heating unit and a semi-automatic launching device. On the engines of VAZ-2111, -2112, the liquid, except for the heater, is fed to the heating unit of the throttle assembly (heated intake manifold is not provided).

At a temperature of 87 ± 2 ° C by overproof valve, the thermostat begins to move, opening the main pipe; In this case, part of the fluid circulates in a large circle through the radiator. At a temperature of about 102 ° C, the nozzle is fully opened, and the entire liquid circulates in a large circle. The progress of the main valve should be at least 8 mm.

Thermostat of the VAZ-2112 engine has an increased resistance of the bypass valve (throttle opening), due to which the fluid flow through the heater radiator increases.

The coolant is poured into the system through the expansion tank. It is made of translucent polyethylene, which allows you to visually control the fluid level. The onboard control system also reports the drop in the level of the fluid, for this, a sensor is provided in the tank cover. Two steam tubes are also connected to the tank: one - from the heater radiator, the other is from the engine cooling radiator.

The radiator consists of two vertical plastic tanks (left - with a partition) and two horizontal rows of round aluminum tubes with pressed coolant plates. To increase the efficiency of cooling the plate stamps with a notch. The tubes are connected to tanks through the rubber gasket. The liquid is fed through the upper nozzle, and is given through the bottom. Next to the intake nozzle is the thin nozzle of the steam tube.

The capacity of the liquid cooling system depends on the size and degree of forcing (for example, the compression ratio) of the engine and the average is 0.2.,. 0.3 liters per horsepower. Therefore, W. passenger cars It contains up to 8 ... 12 liters of liquid, trucks With gasoline carburetor Engine - up to 30 l, and trucks with diesel engine - up to 50 liters. Antifreeze containing anti-corrosion and anti-native additives, as well as additives, excluding scale formation, brand Tosol A-40 or A-65 has a thickening temperature, respectively - 40 and 65 ° C. When the engine is running, the fluid that is washing its cylinders and the head is heated and opens the automatic valve (thermostat) located in the pipeline connecting the engine with the radiator. The pump, which is entered into action from the crankshaft, creates a fluid circulation in the system. Hot liquid passing through the tubes of the radiator, gives heat air supplied to it with a fan. The engine cooling intensity can be changed by changing the intensity of the circulation of the fluid or the intensity of the air flow passing through the radiator, depending on the ambient air temperature or the conditions of movement (speed, load, etc.).