Small and large engine cooling circle. We consider the system

27.06.2020

We are talking about the engine internal combustion. By title it can be seen that the fuel is combustion inside the engine. It turns out heat that warms the motor. For the engine, the optimal temperature is needed at which it works fine. To create and maintain such a given mode, the cooling system is used in many engines, which includes the cooling fluid circulation in the engine.

The system itself complicates the manufacturing process, making it more energy-intensive, which leads to the appreciation of the entire structure. During operation, it is required to conduct regular observation, troubleshooting and repair. Therefore, the cooling system is striving to make the easiest. All systems can be divided into three types:

air;
liquid;
combined.

Using air

The air system is the simplest and cheap, mostly does not require additional equipment and supervision. Two circulation methods are used:

natural;
forced.

The natural way is widely used on high-speed and light moving vehicles, for example, in airplanes, which, as a rule, fly in colder atmospheric layers.

The engine is cooled by air, which is injected with screw. To easy vehicles You can attribute motorcycles and all kinds of models. The engine capacity of such structures is small, natural blowing, basically enough. To increase the heat transfer, the cylinders are made from the engine and are supplied with ribs.

A negative feature of such cooling is the absence of the ability to adjust the engine temperature. In cold weather, it takes a lot of time to warm it, and it is necessary to join the engine so that it is cooled.

This problem is partially solved by a compulsory way. It is used in engines that are installed inpatient. In this case, the air flow coming from the fan is directed to the engine. This thread can be controlled by changing the speed of rotation of the fan.

Eating fluid

In order for the cooling system to be more adjustable and efficient, the liquid cooler is used. In addition, the Tosol movement circuit in the cooling system has two circles: large and small, which also contributes to the uniform temperature. In this capacity used water before. In contrast to air, the water is the best heat transfer, which increases efficiency. Used system can be:

closed;
unlocked.

When using the first system, the liquid circulates along a closed chain. Moves through pipes or hoses of gravity or thanks to the water pump. Heating from the operating engine, it expands, creating a pressure exceeding atmospheric. Therefore, the boiling point reaches 110-120 degrees. For cooling, a heat exchanger is used, which, in turn, is cooled by air flow. To adjust the temperature (coat), the speed of air passing through the heat exchanger is changed. This can be done, opening and closing the blinds or changing the flow rate of the air. Used in powerful engines.

An unlocked system is used where there is no shortage of water - this is a floating. Water comes from the reservoir and with the help of the pump is transmitted to the engine. After cooling the engine, it is thrown out.

The advantage is that it is not necessary to install a heat exchanger and a fan for cooling it.

The work of the combined scheme

Such a system is mainly used in cars and some motorcycles. It includes both liquid and aerial cooling. In the cylinder block, windows are made by which the water flows and heats up.

In order not to disturb the natural movement of the heated fluid, it is fed to the bottom edge of the cylinder, then it rises to the head and goes out. After that, the movement continues on the tube to the radiator's top tank. Running down the tubes of the radiator, the liquid is cooled and the tube is suitable for a water pump, also a member of the pump. From the pump on the tube passes into the lower edge of the cylinder block, and the coolant movement circuit in the engine is closed.

In winter, and when the motor has not yet heated, there is no need for cooling the motor.

To disable the radiator for this time, use the thermostat. Thus, it is a regulator to determine the large and small circle of the cooling system. It is located at the outlet of the coolant from the motor. The thermostat is designed in such a way that with low cooling fluid temperatures overlaps access to the radiator, forming a small circle of engine cooling.

Elements included in the system

The combined circuit of the closed type includes the system of heating the machine interior. Based on this, you can draw up the following list of elements included in the cooling system:

radiators (one for cooling, another for heating);
fans;
water pump (pump);
thermostat;
temperature sensor.

The radiator performs a major role in the cooling system. It is made of two tanks, which are combined with a plurality of brass welded or elongated tubes. From aluminum tubes make less frequently, as their strength is lower. The tubes can be straight or tape, cross-section ellipse. Due to this structure, they are easier to withstand the pressure of the frozen liquid. To increase the heat transfer area, the tubes pass through the package of plates. There is a crane for draining liquid in the lower tank. The top tank is a neck or nozzle leading to an expansion tank. Closed by a plug, inside which are located intake and exhaust valve.

On the lateral side of the radiator there is a temperature sensor indicating the temperature of the coolant. The center establishes a fan for blowing the radiator. Drive he can receive three ways:

Directly from the crankshaft.
Through the coupling.
From the electric motor.

Water centrifugal pump drives fluid throughout the system. Fucked directly on the crankshaft. With a high motor power, oil cooling, installing an oil radiator on the main one.

The cheapest liquid is water, especially if it is soft. It has good heat capacity, has a low viscosity, which allows it to leak through small holes. However, it strongly causes corrosion and freezes with relatively high temperaturesTherefore, it is replaced by Tosol.

In Soviet times there was an institute that was engaged in the development of cooling liquids. The combination of all liquids struggling with freezing, icing is called antifreeze (translated as "against freezing"). These include an aqueous solution of ethylene glycol, less often propylene glycol, which is non-toxic, but significantly more expensive.

Antifreeze not only freeze at lower temperatures, but also less expand during freezing. For example, water is expanding by 9%, and 40% an aqueous solution of ethylene glycol is only 1.5%. The freezing process is also different. Water during freezing turns into a solid monolith, and the solution of ethylene glycol is crystallized, without harming mechanisms.

Additives that are included in antifreeze are aimed at combating corrosion, lubricate foaming parts, fight foam. It is also important that they also have increased the boiling point, which has a beneficial effect on the motor.

With all the advantages of ethylene glycol antifreeze have cons. The main one is high toxicity. For a person weighing 70 kg, 140 milliliters are enough to lead to a fatal outcome. Poison is not only fluid itself, but also its pairs. Even a small leakage in the heating radiator can lead to severe consequences. For timely detection of malfunction, such antifreeze has fluorescent properties.

Another disadvantage is a great expansion coefficient. For new cars, this is not a problem, they already have an expansion tank for this case, but it will be difficult for old ones without refinement. In the hot state, antifreeze will be thrown away, and when it will cool, the level will fall greatly. There is another difficulty, it is much harder to cope with it.

Antifreeze worse transfers heat by about 15-20%. In hot weather, he simply won't cope with his work, and the motor can overheat.

The shelf life of ethylene glycol is limited to 2 to 3 years, at elevated temperatures, the term is strongly reduced, and when the temperature of 105 degrees exceeds, the additives that lubricate the engine parts are rapidly destroyed. Silicate antifreeze uses to improve the quality. In the United States and Japan, phosphate antifreeze are used, but for Europe, due to increased rigidity of water, they are unsuitable.

Recall once again a little about this cooling system.

IN liquid cooling system Special cooling fluids are used - antifreeze different markshaving a thickening temperature - 40 ° C and below. Antifreeze contain anti-corrosion and anti-speaking additives, excluding scale formation. They are very poisonous and demand cautious. Compared to water, antifreeze has a smaller heat capacity and therefore remove heat from the walls of the engine cylinders is less intensively.

So, when cooling with antifreeze, the temperature of the walls of cylinders by 15 ... 20 ° C is higher than when cooling with water. It accelerates the engine heating and reduces the wear of the cylinders, but in the summer it can lead to engine overheating.

Optimal temperature regime The engine with a liquid cooling system is considered to be such at which the temperature of the coolant in the engine is 80 ... 100 ° C on all modes of engine operation.

In car engines applied closed (hermetic) liquid cooling system with forced circulation Coolant.

The inner cavity of the cooling cooling system does not have a permanent connection with the environment, and the connection is carried out through special valves (at a certain pressure or vacuum) located in the radiator stoppers or expansion tank Systems. The coolant in such a system boils at 110 ... 120 ° C. Forced coolant circulation in the system is provided by a liquid pump.

Engine cooling system consists of:

shirt cooling head and cylinder block;
radiator;
pump;
thermostat;
fan;
expansion tank;
connecting pipes and drain cranes.

In addition, the cooling system includes a car body salon.

Principle of operation of the cooling system

I suggest to consider first principal scheme cooling systems.

1 - heater; 2 - engine; 3 - thermostat; 4 - pump; 5 - radiator; 6 - plug; 7 - fan; 8 - expansion tank;
A - a small circle of circulation (the thermostat is closed);
A + b - a large circle circulation (the thermostat is open)

The circulation of fluid in the cooling system is carried out in two circles:

1. Small circle - liquid circulates when starting a cold engine, providing it fast warming.

2. Big circle - The movement circulates when the engine is heated.

If it is easier to speak, then a small circle is circulation of coolant without a radiator, and a large circle - circulation of coolant through the radiator.

The cooling system device differ in its device depending on the car model, however, the principle of operation is one.

The principle of operation of this system can be seen in the following videos:

I propose to disassemble the system of the system on the sequence of work. So, the start of the cooling system occurs when the heart is started in this system - the liquid pump.

1. Liquid pump (Water Pump)

The liquid pump provides forced fluid circulation in the engine cooling system. On the engines of cars apply paddle pumps of centrifugal type.

Search for our liquid pump or water Pompe It follows on the front of the engine (the front part of this one, which is closer to the radiator and where the belt / chain is located).

Liquid pump connected with a belt with crankshaft and generator. So to find our pump enough to find crankshaft And find the generator. We will talk about the generator later, but so far only show what you need to look. The generator looks like a cylinder attached to the engine housing:

1 - generator; 2 - liquid pump; 3 - crankshaft

So, the location was understood. Now let's look at its device. Recall that the device of the entire system and its details are different, but the principle of operation of this system is the same.

1 - pump cover;2 - Stubborn sealing ring of the gland.
3 gland; 4 - pump roller bearing.
5 - hub pulley fan;6 - locking screw.
7 - pump roller;8 - pump housing;9 - Pump impeller.
10 - receiving nozzle.

The pump work is as follows: the pump drive is carried out from the crankshaft through the belt. The belt twists the pump pulley, rotating the hub of the pump pulley (5). He in turn leads to rotation of the pump shaft (7), at the end of which the impeller is located (9). The coolant enters the pump housing (8) through the receiving nozzle (10), and the impeller moves it into the cooling shirt (through the window in the case, visible in the figure, the direction of movement from the pump is shown by the arrow).

Thus, the pump has a drive from the crankshaft, the liquid enters it through the receiving nozzle and goes into the cooling shirt.

Liquid pump work in this video (1:48):

Let's see now, how do liquid go to the pump? And the fluid comes through a very important part - the thermostat. It is the thermostat that is responsible for the temperature regime.

2. THERMOSTAT (THERMOSTAT)

The thermostat automatically adjusts the water temperature to accelerate the engine warming after starting. It is the work of the thermostat that determines how the coolant (large or small) will go.

This unit looks like this in reality:

The principle of operation of the thermostat Very simple: The thermostat has a sensitive element, inside of which the solid filler is located. At a certain temperature, it starts to melt and opens the main valve, and the optional on the contrary is closed.

Thermostat device:

1, 6, 11 - nozzles; 2, 8 - valves; 3, 7 - springs; 4 - cylinder; 5 - diaphragm; 9 - rod; 10 - filler

Thermostat work is simple, you can see it here:

The thermostat has two inlet nozzles 1 and 11, outlet nozzle 6, two valves (main 8, optional 2) and a sensitive element. The thermostat is installed before entering the coolant pump and connects to it through the nozzle 6.

Compound:

Throughpipe 1. Connect fromengine cooling shirt,

Through pipe 11. - With Lower disclosure Bulk radiator.

The sensitive element of the thermostat consists of a cylinder 4, rubber diaphragm of 5 and stock 9. Inside the cylinder between its wall and rubber diaphragm there is a solid filler 10 (fine-crystalline wax) with a high volume extension coefficient.

The main valve 8 of the thermostat with spring 7 begins to open at a coolant temperature of more than 80 ° C. At a temperature of less than 80 ° C, the main valve closes the yield of the fluid from the radiator, and it comes from the engine to the pump, passing through the opening additional valve 2 of the thermostat with spring 3.

As an increase in the temperature of the coolant more than 80 ° C in the sensitive element, a solid filler melts, and its volume increases. As a result, the rod 9 comes out of the cylinder 4, and the balloon moves up. An additional valve 2 begins to close and at a temperature of more than 94 ° C overlaps the coolant pass from the engine to the pump. The main valve 8 in this case opens completely, and the coolant circulates through the radiator.

The valve operation is clear and clearly shown in the figure below:

A - small circle, the primary valve is closed, bypass - closed. B - a large circle, the main valve is open, the bypass - closed.

1 - inlet nozzle (from the radiator); 2 - primary valve;
3 - thermostat housing; 4 - bypass valve.
5 - nozzle of the bypass hose.
6 - Cooling fluid supply pipe into the pump.
7 - thermostat cover; 8 - piston.

So, we dealt with a small circle. Disassembled the device and thermostat, connected. And now let's get to the big circle and the key element of the big circle - the radiator.

3. Radiator (Radiator / Cooler)

Radiator Provides the heat of the cooling fluid heat in environment. On the passenger cars Tubular plate radiators are used.

So, there are 2 types of radiators: collapsible and not collapsible.

The bottom is presented to their description:

I want to say again about the expansion tank (Expansion Tank)

Next to the radiator or the fan is installed on it. Let's now turn to the device of this fan itself.

4. Fan (FAN)

The fan increases the speed and amount of air passing through the radiator. On the engines of cars, four- and hexadener fans are installed.

If a mechanical fan is used,

The fan includes six or four blades (3), glued to the Cross (2). The latter is brought to the pulley of the liquid pump (1), which is driven by the crankshaft using the belt transmission (5).

As we previously talked, the generator (4) also enters the engagement.

If an electric fan is applied,

that fan consists of a 6 and fan motor 5. Fan - four-blade, attached to the motor shaft. The blades on the hub of the fan are located unevenly and at an angle to the plane of its rotation. This increases the flow of the fan and reduces the noise of its operation. For more efficient operation, the electric fan is placed in a casing 7, which is attached to the radiator. Electristant attached to the casing on three rubber bushings. The electric fan is turned on and off automatically sensor 3, depending on the coolant temperature.

So, let's summarize. Let's not alone and summarize on some picture. Do not focus on concrete device, But the principle of work should be understood, for it is the same in all systems, no matter how their device would not differ.

When starting the engine, the crankshaft begins to rotate. Through the belt transmission (I will remind you that it also contains the generator) is transmitted rotation to the pulley of the liquid pump (13). It leads to rotation shaft with an impeller inside the body of the liquid pump (16). The coolant enters the engine cooling shirt (7). Next, through the outlet (4), the coolant returns to the liquid pump through the thermostat (18). At this time, the thermostat is opened by a bypass valve, but closed the main one. Therefore, the fluid circulates through the engine shirt without the participation of the radiator (9). It provides quick engine warming. After the coolant is heated, the main thermostat valve opens and the bypass valve is closed. Now the fluid can not flow through the torus of the thermostat (3) and is forced to flow through the supply nozzle (5) into the radiator (9). There, the liquid is cooled and arrives back into the liquid pump (16) through the thermostat (18).

It is worth noting that some of the coolant comes from the engine cooling shirt into the heater through the nozzle 2 and returns from the heater through the nozzle 1. But we will talk about it in the next chapter.

I hope now the system will become understandable for you. After reading this article, I hope it will be possible to navigate in another cooling system, which realized the principle of operation of this.

I propose to read the same with the following article:

Since we affected the heating system, the next my article will be about this system.

I propose to first consider the circuit circuit of the cooling system.

The circulation of fluid in the cooling system is carried out in two circles:

1. Small circle - The liquid circulates when the cold engine starts, providing its quick heating.

2. Big circle - The movement circulates when the engine is heated.

If it is easier to speak, then a small circle is circulation of coolant without a radiator, and a large circle - circulation of coolant through the radiator.

The cooling system device differ in its device depending on the car model, however, the principle of operation is one.

So, the start of the cooling system occurs when the heart is started in this system - the liquid pump.

Liquid pump (Water Pump)

The liquid pump provides forced fluid circulation in the engine cooling system. On the engines of cars apply paddle pumps of centrifugal type.

Search our liquid pump or water pump should be on the front of the engine (the front part of this one, which is closer to the radiator and where the belt / chain is located).

The liquid pump is connected by the belt with the crankshaft and the generator. Therefore, to find our pump just find the crankshaft and find the generator. We will talk about the generator later, but so far only show what you need to look. The generator looks like a cylinder attached to the engine housing:

1 - generator; 2 - liquid pump; 3 - crankshaft

So, the location was understood. Now let's look at its device. Recall that the device of the entire system and its details are different, but the principle of operation of this system is the same.

1 - pump cover; 2 - Stubborn sealing ring of the gland.
3 gland; 4 - pump roller bearing.
5 - hub pulley fan; 6 - locking screw.
7 - pump roller; 8 - pump housing; 9 - Pump impeller.
10 - receiving nozzle.

Thus, the pump has a drive from the crankshaft, the liquid enters it through the receiving nozzle and goes into the cooling shirt.

Let's see now, how do liquid go to the pump? And the fluid comes through a very important part - the thermostat. It is the thermostat that is responsible for the temperature regime.

Thermostat (Thermostat)

The thermostat automatically adjusts the water temperature to accelerate the engine warming after starting. It is the work of the thermostat that determines how the coolant (large or small) will go.

This unit looks like this in reality:

Thermostat device:

1, 6, 11 - nozzles; 2, 8 - valves; 3, 7 - springs; 4 - cylinder; 5 - diaphragm; 9 - rod; 10 - filler

Compound:

Throughpipe 1. Connect fromengine cooling shirt,

Through pipe 11. - With Lower disclosure Bulk radiator.

The valve operation is clear and clearly shown in the figure below:

A - small circle, the primary valve is closed, bypass - closed. B - a large circle, the main valve is open, the bypass - closed.

So, we dealt with a small circle. Disassembled the device and thermostat, connected. And now let's get to the big circle and the key element of the big circle - the radiator.

Radiator (Radiator / Cooler)

Radiator Provides the heat of the cooling fluid heat into the environment. On passenger cars apply tubular plate radiators.

So, there are 2 types of radiators: collapsible and not collapsible.

The bottom is presented to their description:

I want to say again about the expansion tank (Expansion Tank)

Next to the radiator or the fan is installed on it. Let's now turn to the device of this fan itself.

Fan (FAN)

The fan increases the speed and amount of air passing through the radiator. On the engines of cars, four- and hexadener fans are installed.

If a mechanical fan is used,

The fan includes six or four blades (3), glued to the Cross (2). The latter is brought to the pulley of the liquid pump (1), which is driven by the crankshaft using the belt transmission (5).

As we previously talked, the generator (4) also enters the engagement.

If an electric fan is applied,

that fan consists of a 6 and fan motor 5. Fan - four-blade, attached to the motor shaft. The blades on the hub of the fan are located unevenly and at an angle to the plane of its rotation. This increases the flow of the fan and reduces the noise of its operation. For more efficient operation, the electric fan is placed in a casing 7, which is attached to the radiator. The electric fan is attached to the casing on three rubber bushings. The electric fan is turned on and off automatically sensor 3, depending on the coolant temperature.

So, let's summarize.Let's not alone and summarize on some picture. It is not necessary to emphasize on a specific device, but the principle of work should be understood, for it is the same in all systems, no matter how their device would not differ.

It is worth noting that some of the coolant comes from the engine cooling shirt into the heater through the nozzle 2 and returns from the heater through the nozzle 1.

In any car used internal combustion engine. Wide distribution received liquid systems Cooling - only on old "Zaporozhets" and the new "Tata" is used by blowing air. It should be noted that the circulation scheme on all machines is practically similar - the same elements are present in the design, they are performed by identical functions.

Small circle cooling

In the scheme of the internal combustion engine cooling system, there are two contours - small and large. Something it is similar to the human anatomy - blood flow in the body. Liquid moves in a small circle when it is necessary to make a quick warming up operating temperature. The problem is that the motor can function normally in a narrow temperature range - about 90 degrees.

It is impossible to raise it or lower, as this will lead to violations - the ignition advance angle will change, fuel mixture It will burn untoulated. The circuit includes the radiator of the salon heater - after all it is necessary that inside the car it was warm as soon as possible. Hot antifreeze is overlapped with a crane. The place of its installation depends on the specific car - on the partition between the cabin and motor compartment, in the field of glove, etc.

Big Cooling Contour

In this case, the main radiator is also included. It is installed in the front of the car and is intended for emergency decrease in the temperature of the fluid in the engine. If there is air conditioning on the car, then the radiator is installed nearby. On the Volga and Gazelle cars, an oil radiator is used, which is also placed in the front of the car. The radiator is usually the fan, which is driven by an electric motor, a strap or coupling.

Liquid pump in the system

This device is included in the circuit circulation of the cooling fluid "Gazelle" and any other car. The drive can be implemented as follows:

From the belt of the gas distribution mechanism.
From the generator belt.
From a separate belt.

The design consists of such elements:

Metal or plastic impeller. The effectiveness of the pump depends on the number of blades.
The housing is usually performed from aluminum and its alloys. The fact is that it is this metal that works well in aggressive conditions, corrosion practically does not affect it.
Pulley for installation of the drive belt - gear or wedge-shaped.
The shaft is a steel rotor, at one end of which the impeller is (inside), and outside the pulley to install the drive pulley.
Bronze bushing or bearing - lubrication of these elements is carried out using special additives that are available in antifreeze.
The gland avoids fluid leakage from the cooling system.

Thermostat and its features

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

But on the other hand, if there was no thermostat, the movement would take place exclusively in a small circle. The design contains such items:

Aluminum housing.
Outputs for connecting with nozzles.
Plate of bimetallic type.
Mechanical valve with a return spring.

The principle of operation is that at temperatures below 85 degrees, liquid is moving only by a small contour. At the same time, the valve inside the thermostat is in this position at which antifreeze does not fall into a large circuit.

As soon as the temperature of 85 degrees reach, it will begin to deform it affects the mechanical valve and opens access to the antifreeze to the main radiator. As soon as the temperature decreases, the thermostat valve will return to initial position Under the influence of the return spring.

Expansion tank

In the cooling system of the internal combustion engine, there is an expansion tank. The fact is that any liquid, including antifreeze, when heating increases the volume. And when cooled, the volume decreases. Therefore, some kind of buffer is needed, in which a small amount of fluid will be stored so that in the system it is always plenty. It is with this task that the expansion tank copes - there splashes over during heating.

Lid expansion tank

Another indispensable component of the system is a plug. There are two types of design - hermetic and leakage. In the event that the latter applies the latter, the plug of the expansion tank has only a drainage hole through which the pressure in the system is backed.

But if the hermetic system is applied, then there are two valves in the plug - inlet (takes inside the air from the atmosphere, it works at a pressure below 0.2 bar) and exhaust (it works at a pressure of over 1.2 bar). It throws out of the air surplus system.

It turns out that the system always pressure is more 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 traffic jams in urban conditions. An example of a hermetic system - VAZ-2108 cars and similar. A leshetic - model of the classic VAZ series.

Radiator and fan

The circulation of the coolant passes through the main radiator, which is installed in the front of the car. This place is not chosen by chance - when moving at high speed of the radiator cells are blown by the counter-flow of air, which provides a decrease in the engine temperature. A fan is installed on the radiator. Most of these devices has on "gazelles", for example, clutches are often used similar to those that are installed on air conditioner compressors.

The power on the electric fan occurs with the sensor installed at the bottom of the radiator. It can be used on injection machines a signal from a temperature sensor, which is located on the thermostat case or in the engine block. SAMI simple scheme The inclusion contains only one thermal switch in itself - contacts normally open contacts. As soon as the temperature of the radiator reaches 92 degrees, the contacts inside the switch will be closed and the voltage is supplied to the fan electric motor.

Salon heater

This is the most important part, if you look from the driver's point of view of the driver and passengers. From the efficiency of the stove, comfort depends on riding in the winter season. The heater enters the coolant circulation and consists of such components:

Electric motor with impeller. It turns on by a special scheme in which there is a constant resistor - it allows you to change the frequency of rotation of the impeller.
The radiator is an element for which hot antifreeze passes.
The crane is intended for opening and closing the supply of antifreeze inside the radiator.
The air duct system allows you to direct hot air in the desired direction.

The circuit circulation of the cooling fluid on the system is such that when closing only one input in the radiator, hot antifreeze will not fall into it. There are cars in which the stove crane is missing - hot antifreeze is always inside the radiator. And in the summer, air ducts are simply closed and heat into the cabin is not served.

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