For normal work The engine requires a temperature of 80 - 90 degrees. And the temperature in the cylinder in working condition can grow to 2000 degrees, which destructively affects the details. The cooling system in the car allows the motor not overheat in the heat and not to freeze in the frost. Disruption of the temperature regime is fraught with rapid wear of parts, increased flow Fuel and oils, a drop of engine power.

Thus, the cooling system monitors the temperature limits for the perfect work of the car.

Purpose of air cooling

Direct destination cooling systems - maintain optimal temperature for engine operation. The cooling system is also responsible for heating the air in the cabin, for cooling the engine oil and the working fluid, the automatic can be cooled, the receiving collector and the throttle assembly is cooled. As a result of the combustion of fuel, 35% of heat dissipates.

Did you know? The first cooling system appeared in 1950.

The principle of operation of the cooling air system

The name speaks for itself - the air flow is the main in the air cooling system. Air is removed from the cylinders, the head of the block and the oil radiator. The entire system consists of a fan (drives from the pulley of the crankshaft with a belt), cooling edges of cylinders and heads, removable casing, deflectors and control devices. On the fan there is a protective grid to exclude foreign objects.

The air flow enables the engine with the help of aluminum fan blades. Air moves between the edges of the cooling, and then it is evenly distributed using deflectors to all parts of the motor.

The fan consists of a directing diffuser (around the circle in it there are fixed radially located blades of alternating cross section to direct the air flow) and the rotor with 8 radially located blades. The blades of the diffuser change the direction of the air flow, and it moves to the opposite direction from rotation. This increases the air pressure and is better cooled by the engine.

Interesting to know! In 1997, an air cooling engine was installed with two turbines in 400 horsepower. It is considered the most powerful.

To increase the surface area for contact with air, additional edges are installed on the block and head of the cylinder block. In a minute, the fan can submit 30 cubes of air, which allows the engine to operate at temperatures from -40 ° to + 40 °. Thermostats and dampers allow the engine cooling intensity.

Natural air cooling

Most. simple way Engine cooling is natural air cooling. On the outer surface of the cylinders, the ribs are through which heat is given. Such a cooling system is on motorcycles, mopeds, piston engines and etc.

Forced air cooling

In the system of forced air cooling there is a fan and cooling edges. The casing covers the fan and ribs. This contributes to the direction of the air flow and prevents the penetration of heat from the outside.

Advantages and disadvantages

Benefits Air-cooled engines:

1. Easy design. Easy to repair.

2. Minor weight.

3. Reliability.

4. Inexpensive.

5. Good metric launch rates.

Disadvantages:

1. Creates noise.

2. Motor size increases.

3. Uneven blowing and local overheating.

4. Sensitivity to the quality of fuel, oil and spare parts.

Attention! Even a thin layer of dirt on the motor housing reduces cooling productivity. Therefore, it is necessary to carefully monitor the purity of the engine housing.

Common breakdowns

The sensor shows an increase in oil temperature in - the cooling system gives a failure in operation. Immediately muffle the motor and find out the reason. On the dashboard A lamp lights up, which signals about malfunctions. The reason may be in the fan belt break. The problems in the operation of the thermostat happen very rarely.

Where the engines are used by the cooling system

The engines with the cooling air system are less and less (they are displaced by liquid cooling) in mechanical engineering (compact small males, diesel engine, trucks, agricultural machinery).

Purpose and device engine cooling system

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

Engine overheating impairs quantitative cylinder filling combustible mixture, causes a thinning and burning of the oil, as a result of which, can jam the pistons in the cylinders and the bearing liners will be paid.

The engine supercool causes a decrease in the power and engineering of the engine, pairs of gasoline are condensed on cold parts, and in the form of droplets flow across the cylinder mirror, flushing the lubricant, increase the losses for friction, increases the wear of parts and the need for frequent oil change occurs. And there is also an incomplete combustion of fuel, which is formed on the walls of the combustion chamber, a large nagar layer is formed - valve hangs.

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

The heat balance can be represented as a diagram.

Fig. Engine heat balance diagram internal combustion.

On engines domestic production Apply a closed forced liquid cooling system carried out by a water pump. It is not directly reported with the atmosphere, so called closed. As a result, the pressure in the system increases, the boiling point of the coolant increases to 108 - 119 degrees and the flow rate on its evaporation is reduced.

Cooling system data provide uniform and effective coolingAnd also produce less noise.

Consider the cooling system on the example of the engine ZIL engine

Fig. Engine cooling system circuit type ZIL. 1 - Radiator, 2 - Compressor, 3 - Water Pump, 4 - Thermostat, 5 - Heater Crane, 6 - Leading Tube, 7 - Disposal Tube, 8 - Heater Radiator, 9 - Water Temperature Sensor In Engine Cooling System, 10 - The drain crane of the cylinder block shirt (in the "open" position), 11 is a drain radiator crane.

The liquid in the engine cooling shirt is heated due to the removal of heat from cylinders, comes through the thermostat into the radiator, is cooled in it and under the action centrifugal pump(Provides circulation of coolant in the system) returns to the engine shirt. In the people, the centrifugal pump is called "Pompey". Fluid cooling promotes the intensive blowing of the radiator and the engine with the air flow from the fan. Fanenhances the air flow through the core of the radiator, it serves to improve the cooling of the fluid in the radiator. The fan can have a different drive.

– mechanical- permanent connection with crankshaft engine,

– hydraulic- hydromefta. Hydromefta includes a gummy casing, filled with liquid.

Two spherical vessels D and r are placed in the casing, rigidly connected to the leading A and the slave B shafts, respectively.

Fig. Hydromefta, a - principle of operation; b - device, 1 - Cylinder cover, 2 - body, 3 - casing, 4 - drive roller, 5 - pulley, 6 - fan hub, a - presenter shaft, b - slave shaft, in - casing, g, d - Vessels, T - Turbine Wheel, N - Pumping Wheel.

The principle of operation of the hydraulic fan is based on the actions of the centrifugal force of the liquid. If the spherical vessel d, filled with liquid rotates at high speed, the liquid falls into the second vessel of r, causing it to rotate. Having lost energy when hitting, the fluid returns to the vessel d, accelerates in it, falls into the vessel of r and the process is repeated.

– electric- Controlled electric motor. When the coolant temperature reaches 90-95 degrees, the sensor valve opens the oil channel in the enclosure case and motor oil Enters the working cavity of the hydromule from the main lubricant engine system.

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

Radiatorit serves to cool the water coming from the water shirt.

Fig. Radiator A - device, b - tubular middle, in - plate Mid, 1 - upper tank with nozzle, 2 - steam tube, 3 - plug-in neck with plug, 4 - core, 5 - lower tank, 6 - pipe with drain crane, 7 - tubes, 8 - transverse plates.

It consists of top 1 and lower 5 tanks and cores 4 and fastening parts. Tanks and core are made of brass (to improve thermal conductivity).

The most common tubular and lamellar radiators. In tubular radiators depicted in Figure "B" - the core is formed from a number of thin horizontal plates 8, through which the set of vertical brass tubes passes, due to which the water, passing through the core of the radiator, is divided into a plurality of small pips. Horizontal plates serve as additional ribbies and increase the cooling surface.

Plate radiators consist of one row of flat brass tubes, each of which is made of launched by interference by the edges of corrugated plates.

Thermostatit serves to accelerate the warm-up engine and ensure the optimal temperature mode. The thermostat is a valve that regulates the amount of fluid passing through the radiator.

When starting the engine, the engine itself and the cooling fluid cooling. To accelerate the engine warming, the coolant moves in a circle, bypassing the radiator. The thermostat is closed, as the engine is heated (up to a temperature of 70-80 degrees), the thermostat valve, under the action of the vapor of the liquid filling its cylinder, opens and the cooling fluid opens its movement along big circleThrough the radiator.

On the modern cars Install two-circuit cooling systems. This system includes two independent cooling circuit:

- circuit of cooling block of cylinders;

- circuit of cooling the head of the cylinder block. This text is a familiarization fragment.

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Engine lubrication system malfunctions

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The operation of the internal combustion engine (DVS) leads to excessive heating of all its parts and without cooling them, the functioning of the main unit vehicle It is impossible. This role is performed by the engine cooling system, which is also responsible for heating the auto cabin. In turbocharged engines, it is reduced by the air temperature reached into the cylinders, and this system cools the liquid in the automatic transmission, which is used for its operation. Separate models of cars are equipped with an oil radiator, which takes part in the thermorellation of oil used to lubricate the engine.

The cooling system of the engine is air and liquid

Both of these systems are not perfect and have both advantages and disadvantages.

Benefits air system Cooling:

• low weight of the engine;
• easy device and its maintenance;
• low demanding to temperature changes.

Disadvantages of the cooling air system:

• big noise from engine operation;
• overheating of individual parts of the motor;
• the inability to build cylinders blocks;
• difficult to use heat released to heal the car's cabin.

In modern conditions, automakers prefer to equip their cars mainly by engines with liquid cooling systems. Air structures, cooling motors, are very rare.

Advantages of the liquid cooling system:

• not such a noisy engine compared to the air system;
• high speed of starting work when starting the motor;
• uniform cooling of all parts of the power mechanism;
• less predisposition to detonation.

Disadvantages of the liquid cooling system:

• expensive maintenance and repair;
• possible leakage of fluid;
• frequent motor hyposals;
• freezing of the system in periods of frost.

Structure of the Liquid Engine Cooling System

To the main component of the liquid system cooling in DVS The following details are:

• "Water shirt" engine
• fan;
• radiator;
• pOMP (centrifugal pump);
• thermostat;
• expansion tank;
• heat exchanger heater;
• components of controls.

Water shirt of the engine is the plane between the walls of the unit in those places that require cooling.

The radiator of the cooling system is a mechanism that is intended for the recoil created by the work of the heat engine. The node is a construction of many curved aluminum pipes, which also have additional edges that contribute to greater heat transfer.

The fan is used to accelerate air circulation, enveloping the radiator. The fan turns on under the boundary heating of the coolant.

The centrifugal pump (in other words - pump) provides uninterrupted fluid movement during engine operation. The pump drive may be different: belt, for example, or gear. On a car with turbocked engines, additional pumps are often installed, which contribute to the circulation of the liquid and run from the control unit.

The thermostat is a device in the form of a bimetallic (or electronic) valve located between the inlet of the radiator and the "cooling jacket". This device provides the desired fluid temperature that serves to cool the engine. When the motor cooled, the thermostat is closed, therefore, forced circulation of the cooling fluid passes inside the engine without affecting the radiator. At the time of heating the liquid to the boundary temperature, the valve opens. At this point, the system begins to function in all its power.

The expansion tank is used to inflate the coolant. This node compensates for the change in the amount of fluid in the system during temperature change.

The heater radiator is a mechanism intended for air heating in the vehicle cabin. His working fluid Visits directly near the entrance to the "shirt" of the motor.

The main element of the coordination of the cooling system of the engine is a sensor (temperature), an electronic control unit, as well as actuators.

Engine cooling system

The cooling system operates under the control of the control system force aggregate. The pump launches the circulation of fluid in the "engine cooling shirt". Given the degree of heating, the fluid moves either by small or by a large circle.

In order for the engine faster after launch, the liquid circulates in a small circle. After it is heated, the thermostat opens, providing liquids the ability to circulate through the radiator, at the exit from which the air flow (oncoming or from the operating fan) is affected by the fluid, which cools it.

A double-circuit cooling system can be used in turbocharging motors. A feature of her work is that one contour controls the cooling of the injected air, and the second is cooling the engine.

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 and air cooling systems. 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.

1 - heater radiator 2 - Steam Radiator Hose Hose 3 - Hose Take 4 - Support Hose 5 - Cooling fluid temperature sensor (in block head) 6 - Pump Side Hose 7 - Thermostat 8 - filling hose 9 - Cork expansion tank 10 - Cooling fluid level indicator sensor 11 - Expansion Tank 12 - exhaust pipe 13 - liquid carburetor starter 14 - Distilling radiator hose 15 - Sliding radiator hose 16 - Warehouse Radiator Hose 17 - left radiator tank 18 - electrical fan power sensor 19 - Fan Electric Motor 20 - electrical fan impeller

21 - Radiator's right tank 22 - drain plug 23 - electrical fan housing 24 - toothed belt Driving mechanism of gas distribution 25 - Imprett Cooling Liquid Pump 26 - Sweeping coolant pump tube 27 - Supporting hose to the carburetor launch device liquid 28 - Disposal Hose 27 - Cooling fluid supply hose to throttle nozzle 28 - Cooling fluid drop hose from throttle 29 - Cooling fluid temperature sensor in exhaust pipe 30 - Radiator tubes 31 - radiator core

Cooling system - 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. Exhaust valve Supports elevated (compared to atmospheric) pressure in the hot engine system (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, the sensor associated with the temperature pointer on the dashboard will be screwed into the engine cylinder block head. In the exhaust pipe of injection engines (VAZ-2111, -2112), an additional temperature sensor is installed, outstanding 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. The roller rotates in a double row bearing with a "lifelong" reserve of plastic lubrication. The outer ring of the bearing will stop the screw. On the front end of the roller press toothed pulley, 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. Tubes are connected to tanks through 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, the 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.).

As noted earlier, there are two types of engine cooling systems - liquid and air. They are distinguished by thermal contour and heat carrier, providing heat dissipation from the most heated parts. The main components of the types of cooling systems are presented in Fig. 1.7. Depending on the type of cooling system, there may be different constructive design.

In liquid cooling systems, the coolant circulates along the circuit "Cooling shirt - radiator". The liquid coolant is heated due to the temperature difference between the cylinder walls and the coolant. Heated coolant

Fig. 1.7.

transfers heat to the radiator, where it is partially dissipated in environment Air flow passing through the radiator. This process is continuous due to the constant circulation of fluid. Warm removal is carried out forcibly and regulated.

Liquid cooling systems May be flowing, evaporative and closed.

Flowing cooling systems Press the cooling liquid (water) from natural reservoirs, sent to the engine cooling shirt and after heating are thrown into a pond (Fig. 1.8). These systems are simple in design, their effectiveness depends on the quality and temperature of the water. They are used in stationary, ship and boat hinged engines.

Fig. 1.8.

In flowing systems, the water temperature at the outlet of the engine is about 85 ° C. The temperature difference of water coming out of the engine and the incoming in it does not exceed

15 ... 20 ° С. It is assumed that when cooled by rigid fresh and sea water, the temperature of Pa exit from the engine should not exceed 55 ° C to avoid intensive waste and salts on the internal cavelation systems. This disadvantage of B. ship engines Partially eliminated by using flow-closed cooling systems.

The flow-closed cooling system consists of two liquid contours, one of which is closed, using fresh non-rigid water, the other is a flowful, using water from the water branch (Fig. 1.9). The water of the closed contour from the engine cooling shirt is cooled in the refrigerator, the water circulation is forcibly and is provided with a water pump. Water from a reservoir, which cools the water of a closed circuit is served to the refrigerator. IN closed loop Cooling is provided by an expansion tank to compensate for an increase in water volume when heating, removal from air water and compensation for water leaks from the system.

The temperature of the water coming out of the engine in the closed systems communicating with the atmosphere does not rise above 85 ... 90 ° C. When equipping the expansion tank, the steam-aircraft

Fig. 1.9. The circuit of the combined flow-closed reference system of POM pressure in the system exceeds atmospheric and is 0.12 ... 0.13 MPa, the water temperature increases to 105 ° C.

Fig. 1.10.

The water temperature difference fell out of the engine and the inlet after the refrigerator must be no more than 10 ... 15 °.

Evaporative cooling systems(Fig. 1.10) Provide heat dissipation due to evaporation of coolant (water), washing the most heated engine parts. The distinguished pairs are condensed in the cooling system refrigerator. Water circulation occurs due to the movement of the layers of fluid during the formation and movement of the steam fraction. The evaporative cooling systems are characterized by simplicity of design, require a large amount of water due to evaporation. Evaporative systems are used mainly by the stationary small power of caloric coil engines with a low degree of compression and the ignition of the working mixture from the caloric (caloricate) head.

A closed cooling system with natural cooling fluid circulation is the ter of my background of the cooling system (Fig. 1.11). The circulation of the fluid is carried out due to the pressure occurring at different density of heated and cooled fluid. The coolant in the cavities around the cylinders and in the head during the operation of the engine heats up, rises up and enters the upper tank of the radiator. In the radiator, the liquid under the action of gravitational forces is lowered into the lower tank. The flow of air, which under the influence of the fan passes through the core of the radiator, the liquid is cooled. From the lower tank of the radiator, the cooled fluid enters the engine cooling shirt, displacing the heated layers of the liquid into the top tank of the radiator.

Thermal appendix cooling system has a simple device, less epergazattny, but it works satisfactorily

Fig. 1.11.

cooling

with a large volume of fluid and a significant surface of the radiator cooling. The temperature difference of the coolant at the outlet of the engine and at the inlet after the radiator reaches 30 ° C. On tractors and cars, the thermophone cooling system due to large overall mass parameters, unregulated ™ and large drops of coolant temperatures of the NA applied.

The cooling system with forced circulation of fluid (Fig. 1.12) differs from the thermophone in that after the radiator, the pump is installed. Liquid from the lower tank under pressure is injected into the lower cavity of the cooling shirt, and then passes into the upper cavity and head

The circulation of the liquid from the lower cavity of the cooling shirt in the upper is the disadvantage of this system, since the combustion chamber zone and the head surfaces having the highest temperature flows the liquid already heated. Such circulation of the cooling fluid of the NA contributes to the effective flow of the engine's workflow.

The cooling system with the forced circulation of the liquid can be performed both open and closed. The closed system is separated from the atmosphere and works at an overpressure, as a result of which the boiling point when refueling the system

Fig. 1.12.

liquids

water rises to 105 ... 107 ° C. The working temperature of the cooling water in the closed system is 98 ... 100 ° C, and in an open, communicating with the atmosphere, is 90 ... 95 ° C.

The combined cooling system (Fig. 1.13) is characterized in that the coolant pump will be fed to the upper cavity of the cooling shirt. Water pump provides forced fluid circulation. In the discharge pipe

Fig. 1.13.

a thermostat is installed, a channel (nozzle) is performed on the thermostat installation cavity, connected to the suction cavity of the water pump. When driving the engine, the thermostat sends a liquid, bypassing the radiator, to the pump, which provides intensive engine heating. After reaching operating temperature In the cooling system, the thermostat valve opens and directs the liquid through the radiator. In the cooling system, an excessive pressure is maintained 0.045 ... 0.05 MPa, as a result of which the boiling point of water rises to 107 ... 110 ° C, which reduces the likelihood of its boiling at elevated load modes.

The fluid temperature difference at the outlet of the engine and after the radiator is 5 ... 6 ° C, which ensures favorable conditions for the engine. Combined closed systems with forced circulation and automatic control of fluid temperature is more economical previously considered and widely used on tractors and cars.

Air cooling systems, Unlike liquid, do not have a variety of schemes on the principle of operation. The engine cooling is carried out by the air flow passing through the finned surface of the cylinder. The outer surfaces of the air cooling engine block have casing, deflectors that form an air tract. Air flow in the air path is sent to the most heated engine parts. Air flow movement can be carried out by discharge or suction. A significant lack of a second method is that finned surfaces are intensively polluted and cooling efficiency decreases. The greatest application was the method of injection of air into the air cooler air path. The design of air cooling schemes depends on the location and layout of the cylinders.

The airflow movement circuit is determined by the layout of the fan, its drive. The fan is driven directly from the crankshaft or belt transmission. For efficient and uniform cooling of the engine at the lowest power costs, air should blow the surface of the cooling parts evenly and with a sufficiently high mass rate. Air flow initially must cool the cylinder head, including spark plugs and nozzles.

Fig. 1.14.

In fig. 1.14 The layout circuits of air cooling engines with vertical inline cylinders are presented. The air flow is injected into the air tract, which is formed along one of the lateral sides of the row of engine cylinders.

The aerodynamic resistance of the air tract depends on the installation site and the fan drive. When installing the fan on the axis of the crankshaft, the trajectory of the air particles is extended, the air flow performs several turns before entering the finned surface of the cylinders.

When V-shaped cylinders (Fig. 1.15), it is possible to use one or two injection fans. The fan can be moved directly from the crankshaft or installed so as to direct the flow of air to each row of cylinders and have a belt drive. With the opposite arrangement of cylinders, the air flow is injected into the air tract and enters each series of cylinders (Fig. 1.16).

Regardless of the layout scheme of cylinders, installation and actuator, the principle of operation of the cooling system is unchanged. The main disadvantage of the cooling air system is uneven cooling and a higher engine temperature. The temperature of the internal surfaces of the cylinders and the head reaches 130 ... 140 ° C. The temperature in air cooling systems is supported using devices that control the flow of air flow by moving it through the intercostal channels of cooling surfaces, and other methods. Aerial cooling Widely applied on small engines low power, On high power engines, its use is limited.

Fig. 1.15.