Internal combustion engine. ICE presentation Presentation liquid internal combustion engines

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Physics lesson in grade 8

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Question 1:
What physical quantity shows how much energy is released when burning 1 kg of fuel? What letter do they represent? Specific heat of combustion of fuel. g

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Question 2:
Determine the amount of heat released during the combustion of 200 g of gasoline. g = 4.6 * 10 7J / kg Q = 9.2 * 10 6J

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Question 3:
The specific heat of combustion of coal is approximately 2 times higher than the specific heat of combustion of peat. What does it mean. This means that for the combustion of coal, 2 times more heat is required.

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Engine internal combustion
All bodies have internal energy - earth, bricks, clouds and so on. However, most often it is difficult, and sometimes impossible, to extract it. Most easily, the internal energy of only some, figuratively speaking, "combustible" and "hot" bodies can be used for the needs of a person. These include: oil, coal, warm springs near volcanoes, and so on. Let's consider one of the examples of using the internal energy of such bodies.

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Carburetor engine.
carburetor - a device for mixing gasoline with air in the right proportions.

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Main Main parts of the internal combustion engine parts of the internal combustion engine
1 - filter for intake air, 2 - carburetor, 3 - gas tank, 4 - fuel line, 5 - atomizing gasoline, 6 - intake valve, 7 - glow plug, 8 - combustion chamber, 9 - exhaust valve, 10 - cylinder, 11 - piston.
:
The main parts of the internal combustion engine:

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The work of this engine consists of several stages, repeating one after another, or, as they say, cycles. There are four of them. The clock starts counting from the moment when the piston is at its extreme high point and both valves are closed.

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The first stroke is called the intake (fig. "A"). The intake valve opens and the descending piston sucks the gasoline / air mixture into the combustion chamber. The inlet valve then closes.

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The second measure is compression (fig. "B"). The piston, rising upward, compresses the gasoline-air mixture.

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The third stroke is the working stroke of the piston (Fig. "C"). An electric spark flashes at the end of the candle. The gasoline-air mixture burns out almost instantly and a high temperature builds up in the cylinder. This leads to a strong increase in pressure and the hot gas does useful work - it pushes the piston down.

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The fourth measure is release (fig "g"). The exhaust valve opens, and the piston, moving upward, pushes gases from the combustion chamber into exhaust pipe... Then the valve closes.

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physical education

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Diesel engine.
In 1892 the German engineer R. Diesel received a patent (document confirming the invention) for the engine, which was later named by his last name.

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Principle of operation:
Only air enters the cylinders of the Diesel engine. The piston, compressing this air, does work on it and the internal energy of the air increases so much that the fuel injected there immediately ignites spontaneously. The resulting gases push the piston back, making a working stroke.

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Work steps:
air suction; air compression; fuel injection and combustion - piston stroke; exhaust gas release. A significant difference: the glow plug becomes unnecessary, and its place is taken by a nozzle - a device for injecting fuel; these are usually low-quality gasoline grades.

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Some engine information Engine type Engine type
Some information about engines Carbureted Diesel
History of creation First patented in 1860 by the Frenchman Lenoir; in 1878 it was built by him. inventor Otto and engineer Langen Invented in 1893 by German engineer Diesel
Working fluid Air, sat. gasoline vapors Air
Fuel Gasoline Fuel oil, oil
Max. chamber pressure 6 × 105 Pa 1.5 × 106 - 3.5 × 106 Pa
T at compression of the working medium 360-400 ºС 500-700 ºС
T of fuel combustion products 1800 ºС 1900 ºС
Efficiency: for serial machines for the best samples 20-25% 35% 30-38% 45%
Application B passenger cars relatively low power In heavier machines of high power (tractors, truck tractors, diesel locomotives).

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What are the main parts of the internal combustion engine:

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1. What are the main strokes of the internal combustion engine. 2. In what strokes are the valves closed? 3. In what cycles is valve 1 open? 4. In what cycles is valve 2 open? 5. What is the difference between an internal combustion engine and a diesel engine?

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Dead spots - extreme positions of the piston in the cylinder
Piston stroke - the distance traveled by the piston from one dead center to another
Four-stroke engine - one working cycle occurs in four piston strokes (4 strokes).

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Fill in the table
Stroke name Piston movement 1 valve 2 valve What happens
Inlet
Compression
Working stroke
release
way down
up
way down
up
open
open
closed
closed
closed
closed
closed
closed
Suction of a combustible mixture
Compression of the combustible mixture and ignition
Gases push the piston
Exhaust gas emission

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1. A type of heat engine in which steam rotates the engine shaft without the aid of a piston, connecting rod and crankshaft. 2. Designation of the specific heat of fusion. 3. One of the parts of an internal combustion engine. 4. Cycle cycle of an internal combustion engine. 5. The transition of a substance from a liquid to a solid state. 6. Vaporization from the surface of the liquid.

Description of the presentation for individual slides:

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Car engine Prepared by: Tarasov Maxim Yurievich 11th grade Supervisor: Master of industrial training MAOU DO MUK "Eureka" Barakaeva Fatima Kurbanbievna

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Car engine The internal combustion engine (ICE) is one of the main devices in the design of a car, used to convert fuel energy into mechanical energy, which, in turn, performs useful work. The principle of operation of an internal combustion engine is based on the fact that fuel in combination with air form an air mixture. Combustion cyclically in the combustion chamber, the air-fuel mixture provides high pressure directed to the piston, which, in turn, rotates crankshaft across crank mechanism... Its rotational energy is transferred to the vehicle's transmission. A starter motor is often used to start an internal combustion engine — usually an electric motor that cranks the crankshaft. In heavier diesel engines, an auxiliary ICE ("launcher") is used as a starter and for the same purpose.

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Types of engines There are the following types of engines (ICE): gasoline diesel gas gas diesel rotary piston

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ICEs are also classified: by the type of fuel, by the number and arrangement of cylinders, by the method of forming the fuel mixture, by the number of strokes of the internal combustion engine, etc.

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Gasoline and diesel engines. Duty cycles of gasoline and diesel engine Gasoline internal combustion engines are the most common of car engines... Gasoline serves as fuel for them. Passing through the fuel system, gasoline enters through the spray nozzles into the carburetor or intake manifold, and then this air-fuel mixture is fed into the cylinders, compressed under the influence piston group is ignited by the spark from the spark plugs. The carburetor system is considered obsolete, so the fuel injection system is now widely used. Fuel atomizing nozzles (injectors) inject either directly into the cylinder or into the intake manifold. Injection systems are divided into mechanical and electronic. Firstly, plunger-type mechanical levers are used for fuel metering, with the ability electronic control fuel mixture. Secondly, the process of drawing up and injection of fuel is completely assigned to the electronic control unit (ECU). Injection systems are necessary for more thorough combustion of fuel and minimization of harmful combustion products. Diesel internal combustion engines use special diesel fuel. Engines of this type of car do not have an ignition system: the fuel mixture entering the cylinders through the injectors is capable of exploding under the influence of high pressure and temperature, which are provided by the piston group.

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Gas engines Gas engines use gas as fuel - liquefied gas, generator gas, compressed natural gas. The proliferation of such engines was due to the growing requirements for the environmental safety of transport. The original fuel is stored in cylinders under high pressure, from where it enters the gas regulator through the evaporator, losing pressure. Further, the process is similar to an injection gasoline internal combustion engine. In some cases, gas supply systems may not use vaporizers.

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The principle of operation of the internal combustion engine Modern car is most often driven by an internal combustion engine. There are many such engines. They differ in volume, number of cylinders, power, rotational speed, used fuel (diesel, gasoline and gas internal combustion engines). But, in principle, the device of the internal combustion engine seems to be. How does an engine work and why is it called a four-stroke internal combustion engine? Internal combustion is understandable. Fuel burns inside the engine. Why 4-stroke engine, what is it? Indeed, there are also two-stroke engines. But they are rarely used on cars. The four-stroke engine is called due to the fact that its work can be divided into four, equal in time, parts. The piston will move through the cylinder four times - two times up and two times down. The stroke begins when the piston is at its extreme low or high point. In mechanics, this is called top dead center (TDC) and bottom dead center (BDC).

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The first stroke - the intake stroke The first stroke, also known as the intake stroke, starts from TDC (top dead center). Moving down, the piston sucks the air-fuel mixture into the cylinder. The operation of this stroke occurs when the intake valve is open. By the way, there are many engines with multiple intake valves. Their number, size, time spent in the open state can significantly affect the engine power. There are engines in which, depending on pressing the gas pedal, there is a forced increase in the time that the intake valves are open. This is done to increase the amount of sucked in fuel, which, after ignition, increases the engine power. The car, in this case, can accelerate much faster.

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Second stroke - compression stroke The next engine stroke is the compression stroke. After the piston has reached its lowest point, it begins to rise upward, thereby compressing the mixture that entered the cylinder at the intake stroke. The fuel mixture is compressed to the volume of the combustion chamber. What is this camera? The free space between the top of the piston and the top of the cylinder when the piston is at top dead center is called the combustion chamber. The valves are completely closed during this stroke of the engine. The tighter they are closed, the better the compression is. Of great importance, in this case, is the condition of the piston, cylinder, piston rings... If there are large gaps, then good compression will not work, and accordingly, the power of such an engine will be much lower. Compression can be checked with a special device. By the amount of compression, one can draw a conclusion about the degree of engine wear.

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The third cycle is a working stroke The third cycle is a working one, it starts from TDC. It is no coincidence that he is called a worker. After all, it is in this cycle that the action takes place that makes the car move. In this cycle, the ignition system comes into operation. Why is this system called that? Because it is responsible for igniting the fuel mixture compressed in the cylinder in the combustion chamber. It works very simply - the candle of the system gives a spark. In fairness, it is worth noting that the spark is emitted from the spark plug a few degrees before the piston reaches the top point. These degrees, in modern engine are automatically regulated by the "brains" of the car. After the fuel ignites, an explosion occurs - it sharply increases in volume, forcing the piston to move downward. The valves in this stroke of the engine, as in the previous one, are in a closed state.

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The fourth stroke is the exhaust stroke The fourth stroke of the engine, the last one is the exhaust stroke. Having reached the bottom point, after the working stroke, the exhaust valve in the engine begins to open. There may be several such valves, as well as intake valves. Moving up, the piston removes exhaust gases from the cylinder through this valve - ventilates it. The degree of compression in the cylinders, the complete removal of exhaust gases and the required amount of the sucked-in fuel-air mixture depend on the precise operation of the valves. After the fourth measure, it is the turn of the first. The process is repeated cyclically. And due to what does the rotation take place - the operation of the internal combustion engine for all 4 strokes, which makes the piston rise and fall in the compression, exhaust and intake strokes? The fact is that not all the energy received in the working stroke is directed to the movement of the car. Part of the energy is spent on unwinding the flywheel. And he, under the influence of inertia, turns the crankshaft of the engine, moving the piston during the period of "non-working" strokes. The presentation was prepared based on materials from the site http://autoustroistvo.ru

An internal combustion engine (abbreviated ICE) is a type of engine, a heat engine in which the chemical energy of the fuel (usually liquid or gaseous hydrocarbon fuel is used), combusted in the working area, is converted into mechanical work... Despite the fact that ICEs are a relatively imperfect type of heat engines (loud noise, toxic emissions, a shorter resource), due to their autonomy (the required fuel contains much more energy than the best electric accumulators) ICEs are very widespread, for example in transport.

The history of the creation of internal combustion engines In 1799, the French engineer Philippe Le Bon discovered luminous gas. In 1799, he received a patent for the use and method of producing lamp gas by dry distillation of wood or coal. This discovery was of great importance primarily for the development of lighting technology. Very soon in France, and then in other European countries, gas lamps began to successfully compete with expensive candles. However, luminous gas was not only suitable for lighting.

Gas engine design patent. In 1801, Le Bon took out a patent for the design of a gas engine. The principle of operation of this machine was based on the well-known property of the gas he discovered: its mixture with air exploded on ignition with the release of a large amount of heat. Combustion products expanded rapidly, putting strong pressure on the environment. By creating the appropriate conditions, you can use the released energy in the interests of man. The Lebon engine had two compressors and a mixing chamber. One compressor was to pump compressed air into the chamber, and the other was to pump compressed luminous gas from a gas generator. The air-gas mixture then entered the working cylinder, where it ignited. The engine was double-acting, that is, alternately acting working chambers were located on both sides of the piston. In fact, Le Bon was hatching the idea of an internal combustion engine, but in 1804 he died, not having time to bring his invention to life.

Jean Etienne Lenoir In the following years, several inventors from different countries tried to create a workable lamp gas engine. However, all these attempts did not lead to the appearance on the market of engines that could successfully compete with the steam engine. The honor of creating a commercially successful internal combustion engine belongs to the Belgian engineer Jean Etienne Lenoir. While working in a galvanic plant, Lenoir came to the idea that the air-fuel mixture in a gas engine could be ignited using an electric spark, and decided to build an engine based on this idea. Lenoir was not immediately successful. After it was possible to make all the parts and assemble the car, it worked quite a bit and stopped, because due to heating, the piston expanded and jammed in the cylinder. Lenoir improved his engine by thinking over a water cooling system. However, the second start attempt also failed due to poor piston stroke. Lenoir supplemented his design with a lubrication system. Only then did the engine start to run.

August Otto In 1864, more than 300 of these engines of various capacities were produced. Having become rich, Lenoir stopped working on improving his car, and this predetermined its fate - it was ousted from the market by a more perfect engine created by the German inventor August Otto. In 1864, he received a patent for his model of a gas engine and in the same year entered into a contract with the wealthy engineer Langen to operate this invention. Otto & Company was soon established. At first glance, the Otto engine represented a step backward from the Lenoir engine. The cylinder was vertical. The rotating shaft was placed over the cylinder from the side. A rack connected to the shaft was attached to it along the axis of the piston. The engine worked as follows. The rotating shaft lifted the piston by 1/10 of the cylinder height, as a result of which a rarefied space was formed under the piston and a mixture of air and gas was sucked in. The mixture then ignited. Neither Otto nor Langen possessed sufficient knowledge in the field of electrical engineering and abandoned electric ignition. They were ignited with an open flame through a tube. During the explosion, the pressure under the piston increased to about 4 atm. Under the influence of this pressure, the piston rose, the gas volume increased and the pressure dropped. When the piston was raised, a special mechanism disconnected the rail from the shaft. The piston, first under gas pressure, and then by inertia, rose until a vacuum was created under it. Thus, the energy of the burned fuel was used in the engine with maximum efficiency. This was Otto's main original find. The downward working stroke of the piston began under the influence of atmospheric pressure, and after the pressure in the cylinder reached atmospheric, the exhaust valve opened, and the piston displaced the exhaust gases with its mass. Due to the more complete expansion of combustion products, the efficiency of this engine was significantly higher than the efficiency of the Lenoir engine and reached 15%, that is, it exceeded the efficiency of the best steam engines that time.

Since Otto's engines were almost five times more economical than Lenoir's engines, they immediately became in great demand. In subsequent years, about five thousand of them were produced. Otto worked hard to improve their designs. Soon the gear rack was replaced by a crank drive. But the most significant of his inventions was made in 1877, when Otto took out a patent for new engine with a four-stroke cycle. This cycle is at the heart of most gas and petrol engines to this day. The next year, new engines have already been put into production. The four stroke cycle was Otto's greatest technical achievement. But it was soon discovered that a few years before his invention, exactly the same principle of operation of the engine had been described by the French engineer Beau de Roche. A group of French industrialists challenged Otto's patent in court. The court found their arguments convincing. Otto's rights under his patent were significantly curtailed, including the revocation of his monopoly on the four-stroke cycle. Although competitors launched the production of four-stroke engines, the Otto model, worked out over many years of production, was still the best, and the demand for it did not stop. By 1897, about 42 thousand of these engines of various capacities were produced. However, the fact that luminous gas was used as a fuel greatly narrowed the scope of the first internal combustion engines. The number of lighting and gas factories was insignificant even in Europe, while in Russia there were only two of them - in Moscow and St. Petersburg.

The search for a new fuel Therefore, the search for a new fuel for the internal combustion engine did not stop. Some inventors have tried to use liquid fuel vapors as a gas. Back in 1872, the American Brighton tried to use kerosene in this capacity. However, kerosene evaporated poorly, and Brighton switched to a lighter oil product - gasoline. But in order for a liquid fuel engine to compete successfully with a gas one, it was necessary to create a special device for evaporating gasoline and obtaining a combustible mixture of it with air. Brighton in the same 1872 invented one of the first so-called "evaporative" carburetors, but it worked unsatisfactorily.

Gasoline engine A workable gasoline engine did not appear until ten years later. Its inventor was the German engineer Julius Daimler. For many years he worked for Otto's firm and was a member of its board. In the early 80s, he proposed to his boss a project for a compact gasoline engine that could be used in transport. Otto took Daimler's proposal coldly. Then Daimler, together with his friend Wilhelm Maybach, made a bold decision in 1882, they left the Otto company, acquired a small workshop near Stuttgart and began working on their project. The problem facing Daimler and Maybach was not an easy one: they decided to create an engine that would not require a gas generator, would be very light and compact, but powerful enough to propel the crew. Daimler hoped to increase the power by increasing the shaft speed, but for this it was necessary to ensure the required ignition frequency of the mixture. In 1883, the first gasoline engine was created with ignition from a red-hot hollow tube opened into a cylinder. The first model of a gasoline engine was intended for an industrial stationary installation.

The evaporation process of liquid fuel in the first gasoline engines made you wish for the best. Therefore, the invention of the carburetor made a real revolution in engine building. Its creator is considered to be the Hungarian engineer Donat Banki. In 1893 he took out a patent for a jet carburetor, which was the prototype of all modern carburetors. Unlike his predecessors, Banks proposed not to evaporate gasoline, but to spray it finely in the air. This ensured its uniform distribution over the cylinder, and the evaporation itself took place in the cylinder under the action of the compression heat. To ensure atomization, gasoline was sucked in by an air flow through a metering nozzle, and the consistency of the mixture composition was achieved by maintaining a constant level of gasoline in the carburetor. The jet was made in the form of one or more holes in a tube located perpendicular to the air flow. To maintain the pressure, a small reservoir with a float was provided, which maintained the level at a given height, so that the amount of gasoline drawn in was proportional to the amount of air supplied. The first internal combustion engines were single-cylinder, and in order to increase the power of the engine, the cylinder was usually increased. Then they began to achieve this by increasing the number of cylinders. At the end of the 19th century, two-cylinder engines appeared, and from the beginning of the 20th century, four-cylinder engines began to spread.

Composition Piston engines The combustion chamber is a cylinder, where the chemical energy of the fuel is converted into mechanical energy, which is converted from the reciprocating movement of the piston into rotational by means of a crank mechanism. According to the type of fuel used, they are divided into: A gasoline mixture of fuel with air is prepared in the carburetor and then in the intake manifold, or in the intake manifold using spray nozzles (mechanical or electrical), or directly in the cylinder using spray nozzles, then the mixture is fed into the cylinder, compressed and then ignited with the help of a spark slipping between the electrodes of the candle. Diesel special diesel fuel is injected into the cylinder under high pressure... A combustible mixture forms (and immediately burns out) directly in the cylinder as a portion of the fuel is injected. The mixture is ignited by the high temperature of the compressed air in the cylinder.

Gas engine that burns hydrocarbons as fuel, which are in a gaseous state under normal conditions: Mixtures of liquefied gases are stored in a cylinder under saturated vapor pressure (up to 16 atm). The liquid phase or the vapor phase of the mixture evaporated in the evaporator loses pressure in steps gas reducer to close to atmospheric, and is sucked by the engine into the intake manifold through an air-gas mixer or injected into the intake manifold by means of electric injectors. Ignition is carried out with the help of a spark slipping between the electrodes of the spark plug. Compressed natural gases are stored in a cylinder under atm pressure. The design of the power supply systems is similar to the supply systems with liquefied gas, the difference is the absence of an evaporator. Generator gas is a gas produced by converting a solid fuel into a gaseous fuel. The following are used as solid fuels:

Coal Peat Wood Gas-diesel the main portion of fuel is prepared as in one of the types of gas engines, but it is ignited not by an electric plug, but by an ignition portion of diesel fuel, injected into the cylinder similarly to a diesel engine. Rotary-piston Combined internal combustion engine is an internal combustion engine that is a combination of a piston ( rotary piston) and a blade machine (turbine, compressor), in which both machines are involved in the implementation of the working process. An example of a combined internal combustion engine is piston engine with gas turbine supercharging (turbocharging). RCV is an internal combustion engine, the gas distribution system of which is realized due to the rotation of the cylinder. The cylinder makes a rotational movement alternately passing the inlet and outlet pipes, while the piston reciprocates.

Additional units required for the internal combustion engine The disadvantage of the internal combustion engine is that it only produces high power in a narrow rev range. Therefore, the transmission and starter are integral attributes of an internal combustion engine. Only in some cases (for example, in airplanes) it is possible to do without a complex transmission. The idea is gradually conquering the world hybrid car, in which the motor always runs at its optimum. ICEs are also needed fuel system(for supplying the fuel mixture) and exhaust system(for the removal of exhaust gases).

BPOU Russian-Polyansky Agrarian College

Lesson presentation
on the topic: 1.2 "Internal combustion engines"
On the subject Operation and maintenance of tractors
1 course, specialty - Tractor driver-driver of agricultural production
Developed by - teacher of special disciplines
Goryacheva Lyudmila Borisovna
Russkaya Polyana - 2015

INTERNAL COMBUSTION ENGINES

Internal combustion engines are heat engines, in which the chemical energy of the fuel burning inside the working cavity of the engine is converted into mechanical work.
Internal combustion engines are divided into two groups: compression ignition diesel engines that run on diesel fuel, and carburetor forced ignition engines that run on gasoline, and carburetor engines are used to start them.
A diesel internal combustion engine consists of the main units: a crankcase, a connecting rod-crank mechanism, a gas distribution mechanism, a power supply system, fuel equipment and a regulator, a lubrication system, a cooling system, and a starting device.

ICE classification

Internal combustion engines are divided into two main groups: diesel engines and carburetor engines.
Diesel engines (diesels) are used as the main power plants to create the traction force of the base machine, move it, hydraulic drive mounted and trailed implements, as well as auxiliary purposes (brake control, steering, electric lighting).
Carburetor engines on tractors are used to start the main engine.
The distinctive features of diesel engines include simplicity of design and reliability in operation, efficiency, ease of starting and control, reliability of starting in summer and in cold climates, and stability of operation. Diesel engines provide, in comparison with carburetor engines, higher efficiency from 25 to 32%, lower fuel consumption from 25 to 30%, low operating costs due to the lower price of heavy fuel, simpler in design due to the absence of an ignition system
Internal combustion engines installed on tractors are called autotractor engines.

ICE classification

By appointment
The main engines work constantly during the execution of work cycles, the movement of tractors from one object to another, while performing auxiliary operations.
The starting motors are turned on only when the main engine is started.
By type and method of ignition of combustible mixtures
Diesel engines work by igniting fuel in air. The combustible mixture is ignited by increasing the temperature of the air during compression in the cylinders and atomization of the fuel by the injectors.
Carburetor engines run on a combustible mixture that is prepared in the carburetor and ignited in the cylinders with an electric spark.
By the type of fuel burned
a distinction is made between internal combustion engines that run on heavy liquid fuels (eg diesel, kerosene) and run on light fuel (gasoline with different octane numbers) and gaseous (propane butane).

By the method of forming a combustible mixture
WITH internal mixing carried out in diesel engines, air is sucked in separately and saturated with atomized diesel fuel inside the cylinders before ignition.
WITH external mixture formation used for gasoline and gas fuels. The air drawn in by the engine is mixed with gasoline or gas in the carburetor or mixer until the combustible mixture enters the cylinders.

Duty cycle of a four-stroke, four-cylinder diesel engine Intake stroke.

With the help of an external source of energy, for example electric motor(electric starter), the crankshaft of the diesel engine is rotated and its piston starts to move from the VMT. to N.M.T. (Fig. 1, a). The volume above the piston increases, as a result of which the pressure drops to 75 ... 90 kPa. Simultaneously with the beginning of the piston movement, the valve opens the inlet channel, through which air, having passed through the air cleaner, enters the cylinder with a temperature at the end of the inlet of 30 ... 50 ° C. When the piston comes to n. m., the inlet valve closes the channel and the air supply stops.

Beat compression

With further rotation of the crankshaft, the piston begins to move upward (see Fig. 1, b) and compress the air. In this case, both channels are closed by valves. The air pressure at the end of the stroke reaches 3.5 ... 4.0 MPa, and the temperature is 600 ... 700 ° C.

Expansion stroke, or working stroke

At the end of the compression stroke with the piston position close to v. m. t., finely atomized fuel is injected into the cylinder through a nozzle (Fig. 1, c), which, mixing with highly heated air and gases partially remaining in the cylinder after the previous process, ignites and burns. At the same time, the gas pressure in the cylinder rises to 6.0 ... 8.0 MPa, and the temperature rises to 1800 ... 2000 ° C. Since in this case both channels remain closed, the expanding gases press on the piston, and it, moving downward, turns the crankshaft through the connecting rod.

Release cycle

When the piston comes to n. m. t., the second valve opens the exhaust channel and gases from the cylinder go out into the atmosphere (see Fig. 1, d). In this case, the piston, under the action of the energy accumulated during the working stroke by the flywheel, moves upward, and the inner cavity of the cylinder is cleared of exhaust gases. The gas pressure at the end of the exhaust stroke is 105 ... 120 kPa, and the temperature is 600 ... 700 ° C.

On tractors, carburetor engines are used as a starting device for a diesel engine - small in size and power, internal combustion engines running on gasoline.
The design of these engines is somewhat different from the design of four-stroke. Have two-stroke engine there are no valves that close the channels through which a fresh charge enters the cylinder and the exhaust gases are released. The role of valves is played by piston 7, which, at the right moments, opens and closes the windows connected to the channels, the purge port 1, the outlet port 3 and the inlet port 5. In addition, the engine crankcase is made sealed and forms a curved-spike chamber 6, where the crankshaft is located ...

Working cycle of two-stroke carburetor engine

All processes in such engines occur in one revolution of the crankshaft, that is, in two strokes, which is why they are called two-stroke.
Compression- the first measure. When the piston moves upward, it closes the purge 1 and outlet 3 windows and compresses the air-fuel mixture previously supplied to the cylinder. At the same time, a vacuum is created in the crank chamber 6, and a fresh charge of the fuel-air mixture prepared in the carburetor 4 enters it through the opened intake port 5.
Working stroke, outlet and inlet- second measure. When the upward piston does not reach b. m. t. at 25 ... 27 ° (along the angle of rotation of the crankshaft), a spark jumps in spark plug 2, which ignites the fuel. Fuel combustion continues until the piston arrives at the TDC. After that, the heated gases, expanding, push the piston downward and thereby make a working stroke (see Fig. 2, b). The air-fuel mixture, which is at this time in the crank chamber 6, is compressed.
At the end of the working stroke, the piston first opens the outlet window 3, through which the exhaust gases escape, then the purge window 1 (Fig. 2, c), through which a fresh charge of the fuel-air mixture enters the cylinder from the crank chamber. In the future, all these processes are repeated in the same sequence.

The advantages of a two-stroke engine are as follows.

Since the working stroke in the two-stroke process occurs for each revolution of the crankshaft, the power of the two-stroke engine is 60 ... 70% higher than the power of the four-stroke engine, which has the same dimensions and crankshaft speed.
The design of the engine and its operation are simpler.

Disadvantages of a two-stroke engine

Increased fuel and oil consumption due to the loss of the air-fuel mixture during cylinder purging.
Noise during operation

Control questions

1. What are the internal combustion engines intended for?
Internal combustion engines are designed to convert the chemical energy of the fuel that burns inside the working cavity of the engine into thermal energy, and then into mechanical work.
2. What are the main components of the internal combustion engine?
Crankcase, crank mechanism, gas distribution mechanism, power supply system, fuel equipment and regulator, lubrication system, cooling system, starting device.
3. List the advantages of a two-stroke carburetor engine.
Since the working stroke in the two-stroke process occurs for each revolution of the crankshaft, the power of the two-stroke engine is 60 ... 70% higher than the power of the four-stroke engine, which has the same dimensions and crankshaft speed. The design of the engine and its operation are simpler.
4. List the disadvantages of a two-stroke carburetor engine.
Increased fuel and oil consumption due to the loss of the air-fuel mixture during cylinder purging. Noise during operation.
5. How are internal combustion engines classified according to the number of strokes of the working cycle?
Four-stroke and two-stroke.
6. How are internal combustion engines classified according to the number of cylinders?
Single-cylinder and multi-cylinder.

Bibliography

1. Puchin, E.A. Maintenance and repair of tractors: a tutorial for the beginning. prof. education / E.A. Abyss. - 3rd ed., Rev. and add. - M .: Publishing Center "Academy", 2010. - 208 p.
2. Rodichev, V.A. Tractors: a tutorial for beginners. prof. Education / V.A. Rodichev. - 5th ed., Rev. and add. - M .: Publishing Center "Academy", 2009. - 228 p.

Internal combustion engines

Training center "ONikS"

Internal combustion engine device

1 - cylinder head;

2 - cylinder;

3 - piston;

4 - piston rings;

5 - piston pin;

7 - crankshaft;

8 - flywheel;

9 - crank;

10 - a camshaft;

11 - a cam of a camshaft;

12 - lever;

13 - valve;

14 - spark plug