Interactive diagram of the engine cooling system. Coolant circulation system Small and large coolant circuit

The circulation pattern of the coolant in the engine is approximately the same for each vehicle. During operation, a large amount of heat is generated in an internal combustion engine. To avoid possible problems, this heat must be constantly removed. Due to overheating, even mechanical damage can occur, so if the coolant does not circulate, serious consequences for your car are possible. To avoid such problems, all devices of the cooling mechanism must be set up and work properly.

The temperature in the cylinders during engine operation can reach 800-900 degrees. Even after a few seconds without the operation of the cooling devices, the temperature of the motor rises to an unacceptable level. Heat dissipation processes protect mechanisms and parts that also keep the machine in good working condition and speed up the warm-up of the machine.

However, these are not all the functions that are assigned to the operation of the car's cooling circuit. More modern developments can perform other tasks that contribute to the normal operation of the motor and increase its service life. Among them:

1. Air heating. Most often, this function refers to heating, air conditioning and ventilation devices.
2. Oil cooling. Without lubrication, the car can also overheat, and sometimes this happens even from the constant operation of the engine, so a coolant comes to the rescue.
3. Gas cooling in the recirculation mechanism.
4. Fluid cooling in the gearbox. Working fluids in automatic box also require a decrease in their temperature.

In order to perform the tasks assigned to them properly, cooling systems are different. They differ in cooling methods. There are three types of systems:

1. Liquid system of the closed type;
2. Air system of open type;
3. Combined system.

The most common method of cooling is liquid. It provides even distribution of cold and has the most low level noise at work.

CO components

Schemes of operation of cooling mechanisms include many elements. Each of the parts performs its own functions, respectively, for the ideal operation of all systems, the elements must be in good condition and also they should not be influenced by external negative factors. There are times when coolant is not circulating and this is a sign that one of the components is not working properly.

1. Radiator. Its task is to lower the temperature of the refrigerant under a constant flow of cold air. Heat dissipation is increased, thereby increasing efficiency and cooling capacity, allowing you to get more work done in less time.
   
   
2. An oil cooler can be installed along with the main one. It is designed to cool the lubricant.
3. Another type of device of the same type is a radiator designed to cool exhaust gases. It is necessary to reduce the combustion temperature of the fuel mixture.
4. The task of the heat exchanger is to heat the air. The operation of this device will be more efficient if it is installed at the place where the coolant exits the motor.
5. The expansion tank helps to compensate for the changing volume of the coolant as a result of its expansion.
6. The circulation and movement of the coolant is provided by a centrifugal traction pump. Such a pump is often referred to as a pump. The operating system may differ depending on the type of device. In particular, there are pumps on a belt, and there are pumps on gears. Some powerful engines require installation additional pump the same type.
7. Thermostat. The purpose of this device is to set the level and amount of refrigerant. The entire refrigerant is controlled, so that the most acceptable temperature regime is maintained. You can find the thermostat in the middle between the radiator and the cooling jacket in the pipe.
   
   
8. An electrically heated thermostat is also found on powerful motors. The full opening of such a thermostat occurs with a strong load on the internal combustion engine.
9. Fan - important detail radiator. It increases the cooling intensity and can work on different drives such as mechanical, electrical or hydraulic. Most of the cars are electrically powered.
10. The elements of the control system have their own purpose and allow you to use the entire system on full power. The temperature sensor displays the necessary information on the screen, converting it into a signal.
11. The electronic control unit receives signals from the sensor, converts them into executing signals and transmits the encoded signal to the same devices.
12. The executing devices perform the tasks assigned to them, having received a certain signal. Among them are: a heater, a relay, a fan control unit, another relay for the engine.
    
    

Coolant circuit diagram

For this, cars have an engine cooling system. The centrifugal type pump forces the liquid to move through the engine cooling jacket and the entire system. Operation of the cooling system. The engine cooling jacket is the channels in the block and cylinder head.

Thermostat 7. Regulates the circulation in a small or large circle depending on the temperature. The circulation through the stove is constant, regardless of what position the thermostat is in, and in what circle the liquid circulates.

The pressure in the system is needed in order to raise the boiling point. Even when the temperature reaches 110 degrees, the liquid in the system does not boil. We started cold engine. Immediately we have the circulation of coolant in the system. Fluid circulation is created by pump 6 (Fig. 1), set in motion timing belt or a separate belt.

The liquid will circulate in the following pattern until it reaches a certain temperature. After that, thermostat 7 will close the small circle and open the large one. The cooled fluid is pumped back into the engine by the pump. If the natural cooling of the liquid in the radiator is not enough and the coolant temperature continues to rise, then the fan activation sensor 4, located at the bottom of the radiator, is activated.

At this temperature, the engine is set to optimal thermal gaps, the engine develops maximum power, fuel consumption becomes nominal. Under the guidance of the thermostat, 2 circles of circulation perform their functions (Figure 7.1). The small circle performs the function of engine heating. After heating, the liquid begins to circulate in a large circle and is cooled in the radiator.

Coolant circulates through these channels. The radiator is a set of tubes that form a large cooling surface. This is where the liquid cools down. Expansion tank. With its help, the volume of the liquid is compensated when it heats up and cools down.

The next time you can start your cold engine only after it has been overhaul. The cooling system is needed to remove heat from the mechanisms and engine parts, but this is only half of its purpose, though more than half. To ensure a normal workflow, it is also important to accelerate the warm-up of a cold engine. In figure 25, you can easily distinguish two circles of coolant circulation.

Scheme of the engine cooling system.

And when blue arrows join the red arrows, the already heated liquid begins to circulate in a large circle, cooling in the radiator. To control the operation of the system, there is a coolant temperature gauge on the instrument panel. The pump is driven by a belt drive from the engine crankshaft pulley. When starting a cold engine, the thermostat is closed, and all the liquid circulates only in a small circle (Fig. 25) to warm it up as soon as possible.

At high temperatures, the thermostat opens completely and already all the hot liquid is directed in a large circle for its active cooling. The radiator serves to cool the liquid passing through it due to the air flow that is created when the car is moving or with the help of a fan. The radiator has many tubes and "webs" that form a large cooling surface area.

Cooling systems of various designs

The expansion tank is necessary to compensate for changes in the volume and pressure of the coolant when it is heated and cooled. Pipes and hoses are used to connect the engine cooling jacket to the thermostat, pump, radiator and expansion tank. The hot coolant passes through the heater core and heats the air that enters the vehicle interior. The air temperature in the cabin is regulated by a special tap, with which the driver adds or reduces the flow of fluid passing through the heater radiator.

In other words, you need to put in order the cooling system of your engine. When the temperature in the cooling system rises above 80 - 850, the thermostat automatically opens and part of the liquid enters the radiator for cooling. And this is the second part of the cooling system. The thermostat is designed to maintain a constant optimum thermal regime of the engine. Maintains a certain pressure in the cooling system.

A cooling system is required to maintain optimum engine temperature.

The average temperature of the engine is 800 - 900 ° C, with active operation it reaches 2000 ° C. But periodically it is necessary to remove heat from the engine. If this is not done, the engine may overheat.

But the cooling system not only cools the engine, but also participates in its heating when it is cold.

Most vehicles have a closed-type liquid cooling system with forced circulation of liquid and an expansion tank (Figure 7.1). Rice. 7.1. Scheme of the engine cooling system a) a small circle of circulation b) a large circle of circulation 1 - radiator; 2 - pipe for circulation of coolant; 3- expansion tank; 4 - thermostat; 5 - water pump; 6 - cooling jacket of the cylinder block; 7 - cooling jacket of the head of the block; 8 - heater radiator with electric fan; 9 - heater radiator valve; 10 - plug for draining the coolant from the block; 11 - plug for draining the coolant from the radiator; 12 - fan

The elements of the cooling system are:
• cooling jackets for the block and cylinder head,
• centrifugal pump,
• thermostat,
• radiator with expansion tank
• fan,
• connecting pipes and hoses.

Under the guidance of the thermostat, 2 circles of circulation perform their functions (Figure 7.1). The small circle performs the function of engine heating. After heating, the liquid begins to circulate in a large circle and is cooled in the radiator. The normal coolant temperature is 80-90°C.

The engine cooling jacket is the channels in the block and cylinder head. Coolant circulates through these channels.

The centrifugal type pump helps to move fluid through the jacket and throughout the engine system. causes the liquid to move through the engine cooling jacket and the entire system.

The thermostat is a mechanism that maintains the optimal thermal regime of the engine. When a cold engine is started, the thermostat is closed and the fluid moves in a small circle. When the temperature of the liquid exceeds 80-85 ° C, the thermostat opens, the liquid begins to circulate in a large circle, entering the radiator and cooling.

The radiator is a set of tubes that form a large cooling surface. This is where the liquid cools down.

Expansion tank. With its help, the volume of the liquid is compensated when it heats up and cools down. The fan increases the air flow to the radiator, with which it cools

waiting for liquid.

The pipes and hoses are the connecting mechanism of the cooling jacket with the thermostat, pump, radiator and expansion tank.

The main malfunctions of the cooling system.

Coolant leak. Cause: damage to the radiator, hoses, gaskets and seals. Remedy: tighten hose and tube clamps, replace damaged parts with new ones.

Engine overheating. Cause: insufficient level coolant, weak fan belt tension, clogged radiator tubes, thermostat malfunction. Remedies: restore the liquid level in the cooling system, adjust the fan belt tension, flush the radiator, replace the thermostat.

When the human circulatory system is divided into two circles of blood circulation, the heart is less stressed than if the body had a common circulatory system. In the pulmonary circulation, blood travels to the lungs and then back through the closed arterial and venous system that connects the heart and lungs. Its path begins in the right ventricle and ends in the left atrium. In the pulmonary circulation, blood with carbon dioxide is carried by arteries, and blood with oxygen is carried by veins.

From the right atrium, blood enters the right ventricle, and then through the pulmonary artery is pumped into the lungs. From the right venous blood enters the arteries and lungs, where it gets rid of carbon dioxide, and then saturated with oxygen. Through the pulmonary veins, blood flows into the atrium, then it enters the systemic circulation and then goes to all organs. Since it is slow in the capillaries, carbon dioxide has time to enter it, and oxygen to penetrate into the cells. Because blood enters the lungs at low pressure, the pulmonary circulation is also called the low pressure system. The time of passage of blood through the pulmonary circulation is 4-5 seconds.

When there is an increased need for oxygen, such as during intense sports, the pressure generated by the heart increases and blood flow accelerates.

Systemic circulation

The systemic circulation begins from the left ventricle of the heart. Oxygenated blood travels from the lungs to the left atrium and then to the left ventricle. From there, arterial blood enters the arteries and capillaries. Through the walls of the capillaries, the blood gives oxygen and nutrients into the tissue fluid, taking away carbon dioxide and metabolic products. From the capillaries, it flows into small veins that form larger veins. Then, through two venous trunks (superior vena cava and inferior vena cava), it enters the right atrium, ending the systemic circulation. The circulation of blood in the systemic circulation is 23-27 seconds.

The superior vena cava carries blood from the upper parts of the body, and the inferior vein from the lower parts.

The heart has two pairs of valves. One of them is located between the ventricles and atria. The second pair is located between the ventricles and arteries. These valves direct blood flow and prevent backflow of blood. Blood is pumped into the lungs under high pressure, and it enters the left atrium under negative pressure. The human heart has an asymmetric shape: since its left half does more hard work, it is somewhat thicker than the right.