ICE cooling system principle of operation. Engine cooling system

13.07.2019

for stable and uptime ICE (engine internal combustion) in each car, the engine cooling system is responsible. After all, if cooling does not occur properly, this can lead to overheating of the internal combustion engine, and then to costly repairs. This article will focus on the engine cooling system, its principle of operation and device, as well as solving some problems that arise during operation.

Working principle and main function

The main function of the cooling system is to remove excess heat from the internal combustion engine and prevent it from overheating. And in winter period time, it provides heating of the car interior with the help of a heater radiator. IN standard systems circulation, it cools the heated parts, and in modern cars performs a series additional features, such as:

Cools the working fluid automatic transmission.
Cools the oil in the lubrication system.
Heats up the air.
Cools exhaust crankcase gases.

The principle of operation of the engine cooling system is as follows: the cylinders in the cylinder block are surrounded by a so-called "water cushion" of coolant (coolant), which constantly circulates, thereby achieving the optimum operating temperature.
Antifreeze and antifreeze are used as coolants, and as an exception, distilled water can be added.

Over time, these liquids precipitate, which negatively affects normal cooling. In order to prevent this, the coolant should be replaced in accordance with the regulations service book. To understand how the engine cooling system works, the first step is to consider the device diagram.

Device diagram

The engine cooling system circuit consists of the following direct parts:

cooling radiator basic;
radiator fan;
water pump (pump);
cooling jacket(water cushion);
thermostat ;
heater radiator;
expansion tank.

Such schemes are almost similar for diesel and gasoline engines, there is only a slight difference in the very principle of operation diesel engine. Every detail plays important role for stable and correct operation engine cooling systems, and if one of them fails, this can lead to overheating of the internal combustion engine, and as a result lead to time-consuming and costly repairs. Each element must be considered separately.

Radiator and fan

The radiator of the engine cooling system is one of the main elements and is designed to dissipate into the atmosphere the heat removed from the internal combustion engine by the coolant, and is also responsible for the temperature of the engine. Structurally, the radiator is made of many tubes with fins that increase heat transfer.

The engine cooling fan is designed to improve the efficiency of the radiator. There are 3 types, depending on the drive:

Electric .
Hydraulic .
Mechanical.

The most common fans electric drive. The operation of the fan is activated when the coolant sensor is triggered, thereby reinforcing air flow. In the case when the radiator cells are clogged, you can try to clean them with special means sometimes this method helps.

Water pump

The pump in the car is designed for constant circulation, working coolant. In a water pump, there are often two drives: belt or gear. In cars with an internal combustion engine additionally equipped with a turbocharger, in addition to the main pump, an additional one is installed, which provides more efficient cooling of the turbocharger and charge air.

A “water jacket” is a system of channels for the circulation of coolant that pass through the cylinder head (cylinder head) and serve to remove excess heat, thereby cooling the internal combustion engine.

Thermostat

The next not unimportant node is the thermostat. Its main purpose in the engine cooling system is to regulate coolant flows, accelerate engine warm-up and maintain the set operating temperature in all modes ICE operation. The thermostat is often installed in the pipe coming out of the radiator.

At high internal combustion engine temperature the valve opens in the thermostat and the coolant circulates in a large circle, connecting the radiator to work. In other words, in the case when the thermostat is closed, it moves the coolant in a small circle in the "water jacket", and when it is open, it directs the liquid to the radiator.

Visually, the heater radiator is similar to the main radiator, but it is smaller and is installed inside the car. Its main task is to heat the car interior in the winter. By the way, its breakdown is a common malfunction in winter, and, for example, in Kalina cars, it often fails due to inconvenient fastening, and as a result, heat ceases to flow into the car interior.

Expansion tank with plug-valve

The expansion tank of the engine cooling system is designed to maintain required level cool. Over time, during operation and a change in the temperature of the liquid, its volume also changes, which must be compensated by topping up the coolant. The level must always be monitored and in the event of a minimum acceptable level top it up. Also important detail is a cap-valve expansion tank.

The most common malfunctions

During the operation of the vehicle, there may be various faults with cooling. The most common ones should be considered: air in the cooling system, pressure in the system, breakdown of the thermostat or pump, leak.

Airing is perhaps the most common malfunction that occurs, its fault is the air that got into the system during the topping up of the coolant. In order to eliminate, it is necessary to bleed the air.

Excessive pressure in the engine cooling system can damage rubber pipes or radiators. Simply put, they can simply break. Permissible indicators vary from 1.2 to 2.0 atmospheres. The cap-valve of the expansion tank is responsible for normal pressure, which, if necessary, opens and releases excess steam.

In the event of failure of the thermostat or pump, such a breakdown is eliminated by replacing it with new part. There are cases when a motorist has found traces of a leak, and it is still necessary to get to the nearest service station, then in order not to overheat the internal combustion engine, a sealant is used for the engine cooling system. It is intended to create a seal at the site of a leak, however, it is often not recommended to use it, this is only an extreme measure.

You can repair the engine cooling system yourself, but if the motorist has few skills, it is better to entrust this matter to specialists from service stations.

Outcome

It's time to sum up the information presented. The cooling of the internal combustion engine plays an important role for the correct and stable operation car. You should not forget to monitor the condition of the nodes responsible for cooling, and as the coolant leaves the expansion tank, top it up.

Purpose and arrangement of the engine cooling system

The cooling system is designed to cool the engine parts during its operation and maintain the normal temperature, the most favorable thermal regime of the engine. There are liquid cooling, air cooling and combined cooling.

Overheating of the engine worsens the quantitative filling of the cylinder combustible mixture, causes dilution and burnout of the oil, as a result of which the pistons in the cylinders can jam and the bearing shells will melt.

Overcooling of the engine causes a decrease in engine power and efficiency, gasoline vapor condenses on cold parts and flows down in the form of drops over the cylinder mirror, washing away the lubricant, friction losses increase, wear of parts increases and there is a need for frequent replacement oils. And also incomplete combustion of the fuel occurs, which is why a large layer of soot forms on the walls of the combustion chamber - the valves may hang.

For normal operation engine coolant temperature should be 80-95 degrees.

The heat balance can be presented in the form of a diagram.

Rice. Heat balance diagram of an internal combustion engine.

On engines domestic production use a closed forced liquid cooling system carried out by a water pump. It does not directly communicate with the atmosphere, therefore it is called closed. As a result, the pressure in the system increases, the boiling point of the coolant rises to 108 - 119 degrees and the consumption for its evaporation decreases.

These cooling systems provide uniform and efficient cooling and also produce less noise.

Consider the cooling system on the example of a ZIL engine

Rice. Scheme of the ZIL engine cooling system. 1 - radiator, 2 - compressor, 3 - water pump, 4 - thermostat, 5 - heater tap, 6 - inlet pipe, 7 - outlet pipe, 8 - heater radiator, 9 - water temperature indicator sensor in the engine cooling system, 10 - drain cock of the cylinder block jacket (in the "open" position), 11 - drain cock of the radiator.

The liquid in the engine cooling jacket is heated due to the removal of heat from the cylinders, flows through the thermostat to the radiator, cools in it and under the action of centrifugal pump(provides circulation of coolant in the system) returns to the engine jacket. among the people centrifugal pump called "pump". Cooling of the liquid is facilitated by intensive blowing of the radiator and engine with air flow from the fan. Fan enhances the air flow through the core of the radiator, serves to improve the cooling of the liquid in the radiator. The fan may have various drive.

– mechanical- permanent connection with crankshaft engine,

– hydraulic- hydraulic clutch. The hydraulic coupling includes a hermetic casing B filled with liquid.

Two spherical vessels D and D are placed in the casing, rigidly connected to the driving shaft A and the driven shaft B, respectively.

Rice. Fluid coupling, a - principle of operation; b - device, 1 - cylinder block cover, 2 - housing, 3 - casing, 4 - drive roller, 5 - pulley, 6 - fan hub, A - drive shaft, B - driven shaft, C - casing, D, E - vessels, T - turbine wheel, H - pump wheel.

The principle of operation of the hydraulic fan is based on the action centrifugal force liquids. If a spherical vessel D filled with liquid rotates with high speed, the liquid enters the second vessel D, causing it to rotate. Having lost energy upon impact, the liquid returns to vessel D, accelerates in it, enters vessel D, and the process is repeated.

– electric- controlled electric motor. When the coolant temperature reaches 90-95 degrees, the sensor valve opens oil channel in the switch box and engine oil enters the working cavity of the fluid coupling from the main lubrication system engine.

The fan is enclosed in a casing mounted on the radiator frame, which helps to increase the speed of the air flow passing through the radiator.

Radiator serves to cool the water coming from the water jacket of the engine.

Rice. Radiator a - device, b - tubular middle, c - lamellar middle, 1 - upper tank with a pipe, 2 - steam pipe, 3 - filler neck with a plug, 4 - core, 5 - lower tank, 6 - pipe with a drain cock, 7 - tubes, 8 - transverse plates.

Consists of top 1 and bottom 5 tanks and core 4 and fasteners. Tanks and core are made of brass (to improve thermal conductivity).

The most common tubular and plate radiators. For tubular radiators, shown in figure “b”, the core is formed from a number of thin horizontal plates 8, through which many vertical brass tubes pass, due to which water, passing through the core of the radiator, breaks into many small streams. Horizontal plates serve as additional stiffeners and increase the cooling surface.

Lamellar radiators consist of one row of flat brass tubes, each of which is made of corrugated plates soldered together at the edges.

Thermostat serves to accelerate the warm-up of a cold engine and ensure optimal temperature conditions. The thermostat is a valve that controls the amount of fluid passing through the radiator.

When starting the engine, the engine itself and its coolant are cold. To speed up the warm-up of the engine, the coolant moves in a circle, bypassing the radiator. At the same time, the thermostat is closed, as the engine heats up (to a temperature of 70-80 degrees), the thermostat valve, under the action of the vapors of the liquid filling its cylinder, opens and the coolant begins its movement in a large circle through the radiator.

Installed on modern cars double-circuit cooling systems. This system includes two independent cooling circuits:

– a contour of cooling of the block of cylinders;

– a contour of cooling of a head of the block of cylinders.

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Every car uses an internal combustion engine. Liquid cooling systems are widely used - only on the old "Zaporozhets" and the new "Tata" air blowing is used. It should be noted that the circulation scheme on all machines is almost similar - the same elements are present in the design, they perform identical functions.

Small cooling circle

In the scheme of the cooling system of the internal combustion engine, there are two circuits - small and large. In some ways, it is similar to human anatomy - the movement of blood in the body. The liquid moves in a small circle when it is necessary to produce fast warm-up up to operating temperature. The problem is that the motor can function normally in a narrow temperature range - about 90 degrees.

You can not increase or decrease it, as this will lead to violations - the ignition timing will change, fuel mixture will burn out at the wrong time. The circuit includes a radiator for the interior heater - after all, it is necessary that the inside of the car be warm as soon as possible. The supply of hot antifreeze is blocked with a tap. Its location depends on specific vehicle- on the partition between the salon and engine compartment, in the glove box area, etc.

Large cooling circuit

In this case, the main radiator is also turned on. It is installed in the front of the car and is designed to urgently reduce the temperature of the fluid in the engine. If the car has air conditioning, then its radiator is installed nearby. On cars "Volga" and "Gazelle" is used oil radiator, which is also placed in front of the car. A fan is usually placed on the radiator, which is driven by an electric motor, a belt or a clutch.

Liquid pump in the system

This device is included in the Gazelle coolant circulation circuit and any other car. The drive can be carried out as follows:

From the timing belt.
From the alternator belt.
From a separate belt.

The design consists of the following elements:

Metal or plastic impeller. The efficiency of the pump depends on the number of blades.
Housing - usually made of aluminum and its alloys. The fact is that this particular metal works well in aggressive conditions, corrosion practically does not affect it.
The pulley for installing the drive belt is toothed or wedge-shaped.
Shaft - a steel rotor, at one end of which there is an impeller (inside), and outside a pulley for installing a drive pulley.
Bronze bushing or bearing - lubrication of these elements is carried out using special additives that are available in antifreeze.
The seal prevents fluid from leaking out of the cooling system.

Thermostat and its features

It is difficult to say which element provides the most efficient circulation of fluid in the cooling system. On the one hand, the pump creates pressure and the antifreeze moves through the nozzles with its help.

But on the other hand, if there were no thermostat, the movement would occur exclusively in a small circle. The design contains the following elements:

Aluminum body.
Outlets for connection with nozzles.
Bimetallic type plate.
Mechanical valve with return spring.

The principle of operation is that at temperatures below 85 degrees, the liquid moves only along a small contour. In this case, the valve inside the thermostat is in a position in which antifreeze does not enter the large circuit.

As soon as the temperature reaches 85 degrees, it will begin to deform. It acts on the mechanical valve and opens access to the antifreeze to the main radiator. As soon as the temperature drops, the thermostat valve will return to its original position under the action of a return spring.

Expansion tank

There is an expansion tank in the cooling system of the internal combustion engine. The fact is that any liquid, including antifreeze, increases volume when heated. As it cools, the volume decreases. Therefore, some kind of buffer is needed, which will store not a large number of liquid so that there is always plenty of it in the system. It is with this task that the expansion tank copes - the excess splashes out there during heating.

Expansion tank cap

Another indispensable component of the system is a cork. There are two types of construction - hermetic and non-hermetic. In the event that the latter is used on the car, the plug of the expansion tank has only a drain hole through which the pressure in the system is balanced.

But if a sealed system is used, then there are two valves in the plug - an inlet valve (takes air from the atmosphere inside, operates at a pressure below 0.2 bar) and an exhaust valve (operates at a pressure above 1.2 bar). It expels excess air from the system.

It turns out that the pressure in the system is always greater than in the atmosphere. This allows you to slightly increase the boiling point of antifreeze, which favorably affects the operation of the engine. This is especially good for driving in traffic jams in urban areas. An example of a sealed system is VAZ-2108 cars and the like. Leaky - models of the classic VAZ series.

Radiator and fan

Coolant circulates through the main radiator, which is installed at the front of the vehicle. Such a place was not chosen by chance - when driving at high speed, the radiator cells are blown by an oncoming air flow, which ensures a decrease in engine temperature. A fan is installed on the radiator. Most of these devices have On "Gazelles", for example, clutches are often used, similar to those that are placed on air conditioning compressors.

The electric fan is turned on using a sensor installed at the bottom of the radiator. Can be used on injection machines a signal from a temperature sensor, which is located on the thermostat housing or in the engine block. The most simple circuit switching on contains only one thermal switch - it has normally open contacts. As soon as the temperature reaches 92 degrees at the bottom of the radiator, the contacts inside the switch will close and voltage will be applied to the fan motor.

Cabin heater

This is the most important part when viewed from the perspective of the driver and passengers. Comfort when driving depends on the efficiency of the stove. winter time of the year. The heater is part of the coolant circulation circuit and consists of the following components:

Electric motor with impeller. It is turned on according to a special scheme in which there is a constant resistor - it allows you to change the speed of the impeller.
The radiator is the element through which the hot antifreeze.
The crane - is intended for opening and closing of supply of antifreeze in a radiator.
The duct system allows you to direct hot air in the right direction.

The scheme of circulation of the coolant through the system is such that when only one inlet to the radiator is closed, hot antifreeze will not get into it in any way. There are cars in which there is no stove tap - there is always hot antifreeze inside the radiator. And in summer time air ducts are simply closed and heat is not supplied to the cabin.

The figure shows fluid system carburetor cooling V-engine. Each row of the block has a separate water jacket. The injected water by the water pump 5 is divided into two streams - into the distribution channels and then into the water jacket of its block row, and from them into the cylinder head jackets.

Rice. Engine cooling system ZMZ-53: a - device; b - core; in - blinds; 1 - radiator; 2 - liquid overheat indicator sensor; 3 - radiator cap; 4 - casing; 5 - water pump; 6 - bypass hose; 7 and 12 - outlet and inlet hoses, respectively; 8 - thermostat; 9 - liquid temperature sensor; 10 - drain tap fitting; 11 - cooling jacket; 13 - fan belt; 14 - drain cock; 15 - fan; 16 - blinds; 17 - heater fan; 18 - cab heater; 19 - blind plate; 20 - cable

During the operation of the cooling system, a significant amount of liquid is supplied to the most heated places - pipes exhaust valves and spark plug sockets. In carburetor engines, water from the cylinder head jackets first passes through the water jacket of the intake pipe, washes the walls and heats the mixture coming from the carburetor through the internal channels of the pipe. This improves the evaporation of gasoline.

The radiator serves to cool the water coming from the engine water jacket. The radiator consists of upper and lower tanks, a core and fasteners. Tanks and core for better heat conduction are made of brass.

In the core there is a row of thin plates, through which a lot of vertical tubes pass, soldered to them. Water entering through the core of the radiator branches into a large number of small streams. With such a structure of the core, the water is cooled more intensively due to an increase in the area of contact of water with the walls of the tubes.

The upper and lower tanks are connected by hoses 7 and 12 to the engine cooling jacket. A faucet 14 is provided in the lower tank to drain water from the radiator. To lower it from the water jacket, there are also taps in the lower part of the cylinder block (on both sides).

Water is poured into the cooling system through the neck of the upper tank, which is closed with a stopper 3.

To cab heater 18 hot water comes from the water jacket of the block head and is discharged by a pipe to the water pump. The amount of water supplied to the heater (or the temperature in the driver's cab) is regulated by a tap.

The liquid cooling system provides for double regulation of the thermal regime of the engine - with the help of shutters 16 and thermostat 8. The shutters consist of a set of plates 19, which are pivotally fixed in the bar. In turn, the bar is connected by a rod and a system of levers to the blinds control handle. The handle is located in the cab. The doors can be placed vertically or horizontally.

The water pump and fan are combined in one housing, which is attached to the platform on the front wall of the crankcase through a sealing gasket. In the case of 7 pumps per ball bearing x, a roller 4 is installed. At its front end, a pulley 2 is fixed with the help of a hub. A crosspiece is screwed to its end, to which the impeller 1 of the fan is riveted. When the engine is running, the pulley receives rotation from the crankshaft through the belt. The blades of the impeller 1, located at an angle to the plane of rotation, take air from the radiator, creating a vacuum inside the fan casing. Thereby cold air passes through the core of the radiator, taking away heat from it.

At the rear end of the roller 4, the impeller 5 of the centrifugal water pump is rigidly planted, which is a disk with curved blades evenly spaced on it. When the impeller rotates, the fluid from the inlet pipe 8 flows to its center, is captured by the blades and, under the action of centrifugal force, is thrown to the walls of the housing 7 and is fed through the tide into the engine water jacket.

Rice. Water pump and engine fan ZIL-508: 1 - fan impeller; 2 - pulley; 3 - bearing; 4 - roller; 5 - pump impeller; 6 - gasket; 7 - pump housing; 8 - inlet pipe; 9 - bearing housing; 10 - cuff; 11 - sealing washer; 12 - gland seal holder

A gland seal is also provided at the rear end of the roller 4, which does not allow water to pass from the engine water jacket. The seal is mounted in the cylindrical hub of the impeller and locked in it with a spring ring. It consists of a textolite sealing washer 11, a rubber cuff 10 and a spring that presses the washer against the end face of the bearing housing. With its protrusions, the washer enters the grooves of the impeller 5 and is fixed by the holder 12.

On the KamAZ car engine, the fan is located separately from the water pump and is driven through hydraulic clutch. The hydraulic coupling (fig. a) includes a hermetic casing B filled with liquid. Two (with transverse blades) spherical vessels D and G are placed in the casing, rigidly connected to the driving A and driven shafts B, respectively.

The principle of operation of the fluid coupling is based on the action of the centrifugal force of the fluid. If you quickly rotate a spherical vessel D (pumping) filled with a working fluid, then under the action of centrifugal force, the liquid slides along the curved surface of this vessel and enters the second vessel G (turbine), causing it to rotate. Having lost energy upon impact, the liquid again enters the first vessel, accelerates in it, and the process is repeated. Thus, rotation is transmitted from the drive shaft A, connected to one vessel D, to the driven shaft B, rigidly connected to another vessel G. This principle of hydrodynamic transmission is used in engineering when designing various mechanisms.

Rice. Fluid coupling: a - principle of operation; b - device; 1 — a cover of the block of cylinders; 2 - body; 3 - casing; 4 - drive roller: 5 - pulley; 6 - fan stages; A - drive shaft; B - driven shaft; B - casing; D, D - vessels; T - turbine wheel; H - pump wheel

The hydraulic coupling is located in the cavity formed by the front cover 1 of the cylinder block and the body 2 connected by screws. The hydraulic coupling consists of a casing 3, pump H and turbine G wheels, driving A and driven B shafts. The casing is connected through the drive shaft A to the crankshaft using the drive shaft 4. On the other hand, the casing 3 is connected to the impeller and the pulley 5 of the generator drive and the water pump. The driven shaft B rests on two ball bearings and is connected at one end with turbine wheel, and the other - with the hub 6 of the fan.

The engine fan is located coaxially with the crankshaft, the front end of which is connected by a splined shaft to the drive shaft 4 of the fluid coupling drive. By turning the hydraulic clutch switch lever, you can set one of the required fan operation modes: "P" - the fan is always on, "A" - the fan turns on automatically, "O" - the fan is off ( working fluid released from the casing). In the "P" mode, only short-term operation is allowed.

Automatic activation of the fan occurs when the temperature of the coolant surrounding the thermal force sensor rises. At a coolant temperature of 85 ° C, the sensor valve opens the oil channel in the switch housing and the working fluid - engine oil - enters the working cavity of the fluid coupling from the main line of the engine lubrication system.

The thermostat serves to accelerate the warm-up of a cold engine and automatically regulate its thermal regime within the specified limits. It is a valve that regulates the amount of fluid circulating through the radiator.

On the engines under study, single-valve thermostats with a solid filler - ceresin (petroleum wax) are used. The thermostat consists of a housing 2, inside which is placed a copper cylinder 9 filled with an active mass 8, consisting of copper powder mixed with ceresin. The mass in the cylinder is tightly closed with a rubber membrane 7, on which a guide sleeve 6 is installed with a hole for the rubber buffer 12. The latter has a rod 5 connected by a lever 4 to the valve. In the initial position (on a cold engine), the valve is tightly pressed against the seat (Fig. b) of the body 2 by a spiral spring 1. The thermostat is installed between pipes 10 and 11, which drain the heated liquid to the upper radiator tank and the water pump.

Rice. Thermostat with rotary (a-c) and simple (d) valves: a - thermostat device with a rotary valve ( carbureted engine ZIL-508); b - the valve is closed; in - the valve is open; d - thermostat device with a simple valve (3M3-53 carburetor engine); 1 - spiral spring; 2 - body; 3 - valve (flap); 4 - lever; 5 - stock; 6 - guide sleeve; 7 - membrane; 8 - active mass; 9 - balloon; 10 and 11 - branch pipes for draining liquid to the radiator and water pump; 12 - rubber buffer; 13 - valve; 14 - spring; 15 - body saddle; A - valve stroke

At a coolant temperature above 75 °C, the active mass melts and expands, acting through the membrane, buffer and rod 5 on lever 4, which, overcoming the force of spring 1, begins to open valve 3 (Fig. c). The valve will fully open at a coolant temperature of 90 °C. In the temperature range of 75 ... 90 ° C, the thermostat valve, changing its position, regulates the amount of coolant passing through the radiator, and thereby maintains normal temperature regime engine.

Figure d shows a thermostat with a simple valve 13 in the position when it is fully open to allow fluid to pass into the radiator, i.e. when its stroke is equal to distance A. At a temperature of 90 °C, when the active mass of the cylinder is melted, the valve sits down together with the cylinder, overcoming the resistance of spring 14. As it cools, the mass in the cylinder contracts and the spring lifts the valve up. At a temperature of 75 °C, the valve 13 is pressed against the seat 15 of the housing, closing the liquid outlet to the radiator.

Rice. Steam valve: a - steam valve is open; b - the air valve is open; 1 and 6 - steam and air valves, respectively; 2 and 5 - springs of steam and air valves; 3 - steam pipe; 4 - plug (cap) of the radiator filler neck

A steam-air valve is necessary to communicate the internal cavity of the radiator with the atmosphere. It is mounted in the plug 4 of the radiator filler neck. The valve consists of a steam valve 1 and placed inside it air valve 6. The steam valve, under the action of spring 2, tightly closes the radiator neck. If the temperature of the water in the radiator rises to the limit value (for this engine), then under the steam pressure the steam valve opens and its excess comes out.

When a vacuum is created in the radiator during cooling of water and condensation of steam, the air valve opens and water enters the radiator. atmospheric air. The air valve closes under the action of spring 5 when the air pressure inside the radiator is balanced with atmospheric pressure. Through the air valve, water is drained from the cooling system with the neck cover closed. At the same time, the radiator tubes are protected from destruction under the influence of atmospheric pressure during the engine cooling process.

To control the temperature of the coolant are signal lamp and remote thermometer. The lamp and thermometer pointer are located on the instrument panel, and their sensors can be in the cylinder head, in the drain pipe, inlet pipe or in the upper radiator tank.

Briefly about how the cooling system of a car engine works.

Answer the question which part of the car is more important:, or the engine cooling system? If you have chosen one or two of the suggested positions in the list, you have answered incorrectly. In fact, all of the above positions are vital for any machine. Failure in each of them will lead to serious consequences that will not be easy to fix.

Take, for example, the engine cooling system. If it is faulty or the engine operation mode exceeds the performance indicators laid down during its design, it is likely that you can see a rare phenomenon that will later come to you in nightmares, thick hot steam will begin to pour out from under the hood, and the arrow of the engine temperature sensor will rest against the red zone marking the critical overheating of the motor. After such a steam bath and extreme temperatures, the engine may well go to a car service for overhaul Or straight to the landfill. This is the result incorrect operation cooling systems.

And so, the first helpful information for newbies. The purpose of the cooling system is to create ideal thermal operating conditions for the engine, which will exclude the possibility of overheating. Exothermic reactions occur in the internal combustion engine (that is, it produces a large amount of heat) and if the cooling system is not able to take excess heat from the cylinder block, the engine will begin to deform (may move the cylinder head), the oil will not be able to provide sufficient protection (its protective properties deteriorate), the engine will begin to wear out quickly and eventually it will jam.

The most important part of the engine cooling system is by far the water pump. It forces the ethylene glycol-based coolant to circulate through the hottest parts of the engine, as well as through the thermostat housing, radiator, heater core and other pipes and hoses entering the cooling system.

All internal combustion engines are cooled by convective heat transfer (heat transfer in unevenly heated liquid, gaseous and other fluids, read more here: yandex.ru) and almost all modern cars use ethylene glycol-based fluid as liquid antifreeze. It has a number of advantages over other technical liquids, such as high heat capacity, very heat boiling and low temperature freezing. It is it that is pumped through the engine by a water pump driven from the crankshaft by a drive belt for the drive of auxiliary units.

How does a thermostat work?

The thermostat uses wax. Wax poured into a brass or aluminum capsule, when heated, pushes a small piston away from the thermostat housing, compressing the spring. The thermostat opens. After the system has cooled, the spring returns the thermostat to the closed position (the thermostat operation is shown at 5.37 minutes of the video. By the way! This option shown can be used as a test of the thermostat from your car if you doubt its proper functioning)

On a cold engine, the coolant flows in a so-called small circle through the cylinder block, the cylinder head, called the "head" and (for this reason you immediately get warm air in the cabin after starting the engine).

Once the engine reaches about 95 degrees, the wax in the thermostat expands and opens a valve to direct coolant from the engine to the radiator.

How is a cooling radiator arranged?

The heated coolant passes through the radiator tubes, giving off heat from the coolant (liquid) to the tubes, then transferring it to the radiator fins (the fins are made of corrugated metal). The fins, with their large surface area, contribute to high heat transfer when meeting with the oncoming flow of cooled air (to increase the cooling effect or in cases where the car is stationary, a large fan is placed in front of the radiator, which additionally drives the air through the cooling fins). Thus, the coolant flowing through the radiator grill is cooled and enters the opposite tank on the radiator. The cycle repeats, the cooled liquid returns to the water pump and cools the engine, the circle is closed.

A section of the radiator shows us two rows of tubes through which the coolant passes, which transfers heat from the engine to the fins of the grille.