It was specifically transport. He ate a mixture of liquid fuel and air, and sparingly. The shaft rotation speed was 4-5 times higher than that of gas engines, and the liter power (hp/l) was twice that. There was less mass per unit of power.

The first Benz engines had a shaft speed not exceeding 400 rpm; and Benz justified this slowness by the durability and quietness of the engine. The crank mechanism remained open, like stationary engines. The most interesting thing about the Benz engine is the electric ignition of the mixture, which is basically the same as in current engines. Unfortunately, it worked very unstable.

Increased engine power

Increasing engine power and thus vehicle speed was not so easy. If you increase the diameter of the cylinder, the forces acting on its walls and on the part increase crank mechanism. If you increase the piston stroke length, the cylinder becomes difficult to place on the car, and the dimensions of the crank parts increase. In both cases the engine becomes heavier. These circumstances led the designers to the idea of multiplying the number of cylinders. Daimler made its earliest engines with two-cylinder (U-shaped) engines, and in 1891 built the first four-cylinder.

Increasing the number of cylinders not only made the engine more compact while its power increased, but also made it run smoother. In a four-cylinder engine, each power stroke is half a revolution crankshaft, while one cylinder engine- two turns. At the same time, the design and assembly of an engine with several cylinders is more complex; distortions and shaft deflection occur. It was necessary to introduce counterweights on it, increase the number of its supports, and install an auxiliary balancing shaft nearby.

By the end of the century, many companies produced simultaneously one-, two- and four-cylinder engines. We tried to use the same cylinders on all the company's engines in order to adjust mass production and simplify their replacement in case of damage. They also tried to make the cylinder head removable (as is done now) to facilitate engine assembly and valve maintenance, but they could not achieve tightness of the gap between the head and the cylinder; heating caused deformation of the head, the tightness was broken. Then they began to cast the cylinder together with the head, and for access to the valves they made hatches with threaded plugs. The casting turned out to be intricate. Therefore, the water cooling jacket was removable (hence its name), made of brass or copper. It was secured with screws.

An important place was occupied by the distribution system, i.e., filling the cylinders with a combustible mixture and cleaning them from gases. In all early engines, the mixture was injected into the cylinder by an automatic poppet valve - a “plate” on a rod like an overturned mushroom. The shape of the valve is similar to the current one, it opened due to the vacuum in the cylinder during the intake stroke, and the rest of the time was kept in the closed position by a spring and pressure in the cylinder. Despite frequent jamming, the simplicity of the design of such a valve attracted specialists until the first years of the 20th century. And then, with an increase in shaft rotation speed, they switched to a controlled valve.

From the very beginning, the exhaust valve was controlled like a spool steam engine, using an eccentric and traction. With the abandonment of the automatic valve and the increase in the number of cylinders, the number of eccentrics also increased. This prompted the designers to think about a single shaft with cams instead of eccentrics, driven by the crankshaft. The cams were installed so that their protrusions lifted the valve stems at the right moment. At further movement The cam spring held the valve closed. The design of the distribution mechanism acquired a design that has survived to this day. To compensate for the imperfections of the carburetors of that time, this mechanism was given one more function: the driver could use a special (another!) lever - a switch to shift camshaft and remove the cams from under the valves and temporarily stop their action.

Although it would seem car engine unlike the stationary one, it was possible to cool it with a flow of oncoming air; the designers very soon came to the conclusion that greater efficiency water cooling. It went through a number of stages of development until serpentine radiators proliferated, sometimes encircling the entire engine hood. The coils, despite their bulkiness, large mass and possible failures, lasted about 15 years. The Mercedes model (1901) was the first to use the now familiar tubular or honeycomb radiator with a large cooling surface, which changed the appearance of the car. At the end of the 19th century, water pumps rotated by a crankshaft appeared. To blow air through the radiator, especially during slow driving, a fan was used, located behind the radiator or combined with the engine flywheel (in this case, a casing was placed under the engine to seal the engine compartment).

By the beginning of the 20th century, the engine splash lubrication system was established. Scoops on the lower heads of the connecting rods agitated the oil that filled the crankcase, its drops lubricating the cylinders and bearings. To lubricate other mechanisms of the car, a whole battery of “droppers” was intended, which was located on the front panel or on the side of the body. From time to time the driver or his assistant pressed the dropper buttons.

In the development of devices designed to supply the mixture into the cylinders and ignite it, it was necessary to come into contact with relatively new scientific disciplines: electrical engineering, gas and hydrodynamics.

Long before the advent of automobiles, the spray gun was known. It was worth placing it on the path of gasoline from the tank to the engine, and the vacuum in the cylinders during the intake stroke would create an air draft and spray the gasoline. Mixing with air, it formed a flammable mixture. However, the designers believed that such a “barber” design was too delicate for the crude engines of the time.

The advent of carburetors

Various intricate carburetors were invented. The operation of the Marcus carburetor resembles the process of spraying paint from a brush (hence the name brush carburetor). In a Benz "bubbling" (churning) carburetor, air was forced through the thickness of the gasoline in the tank. The layer of gasoline became thinner as it was consumed, and the mixture became less saturated; The device worked normally only at the beginning of the trip. They abandoned the wick carburetor, because due to the vacuum in the cylinder, sometimes the wicks themselves were sucked in and the engine stopped. When using a surface carburetor, the driver had to constantly monitor the gasoline level.

Having failed to achieve the desired result, the designers turned to the rejected spray gun. The Daimler and Maybach spray carburetor consisted of a float and mixing chambers. A constant fuel level was automatically maintained in the float chamber. Thanks to the vacuum, gasoline came out of the mixing chamber nozzle, like from a spray bottle, in a sprayed stream. This scheme has, in principle, survived to this day.

Ignition systems

Diversity constructive solutions This is also typical for early ignition systems. Their “effectiveness” is evidenced by the words “Good ignition!” with which motorists once greeted each other. And now among drivers the term “long ignition” (towing a failed car) has been preserved.

Lenoir electrical devices were so imperfect that the first Benz car equipped with them could only work on very flat roads, in dry weather and close to charging station or having a supply of dry Bunsen elements “on board”. They tried to replace them with a dynamo, but it did not work at low speeds; To start the engine, it was necessary to manually very vigorously spin its shaft or accelerate the car in some way. Acid battery he was still very heavy, energetically weak, and was deteriorating from shaking.

Many automakers were attracted by the “Magnetic pull-off ignition” invented in 1895 by German electrical engineer Robert Bosch (1861 -1942). This system generated current by moving an armature in an electric field between the poles of a magnet. At the moment of greatest current electrical circuit the thrust driven by the anchor was torn apart. The rupture occurred in the combustion chamber. A spark appeared, igniting the mixture. The system worked reliably if the engine speed did not exceed 300 rpm.

G. Daimler and V. Maybach, who sought high speed engine, none of the then electrical systems ignition was not satisfactory. Therefore, until the very end of the 19th century, Daimler cars used a platinum glow tube, despite its high cost, fire hazard and the fact that it often caused premature ignition of the mixture. In Germany, a bill was even prepared to ban glow ignition. Daimler was the first to use production car a magnetoelectric machine with two armature windings proposed by R. Bosch. It was called a “high voltage magneto”. It made it possible to achieve reliable ignition and did not depend on engine speed. Magneto-powered cars lasted until the 1930s.

This is how the car engine was created step by step. Its power increased by the beginning of the 20th century tens of times, and its specific power increased by 7 times, fuel consumption per 1 liter. With. halved. Similarities with stationary engines almost lost, except for the most general ones.

First engine internal combustion(ICE) was invented by the French engineer Lenoir in 1860. This engine was in many respects the same as a steam engine, running on illuminating gas in a two-stroke cycle without compression. The power of such an engine was approximately 8 hp, the efficiency was about 5%. This Lenoir engine was very bulky and therefore did not find further use.

7 years later, the German engineer N. Otto (1867) created a 4-stroke compression ignition engine. This engine had a power of 2 hp, with a speed of 150 rpm and was already in mass production.

10 hp engine had an efficiency of 17%, a mass of 4600 kg and found wide application. In total, more than 6 thousand of these engines were produced.

By 1880, the engine power was increased to 100 hp.

Fig 3. Lenoir engine: 1 – spool; 2 – cylinder cooling cavity: 3 – spark plug: 4 – piston: 5 – piston rod: 6 – connecting rod: 7 – ignition contact plates: 8 – spool rod: 9 – crank shaft with flywheels: 10 – spool rod eccentric.

In 1885 in Russia, captain of the Baltic Fleet I.S. Kostovich created an engine for aeronautics with a power of 80 hp. with a mass of 240 kg. At the same time, in Germany, G. Daimler and, independently of him, K. Benz created a low-power engine for self-propelled vehicles - cars. This year marks the beginning of the era of automobiles.

At the end of the 19th century. The German engineer Diesel created and patented an engine, which later began to be called the Diesel engine after the author. The fuel in a Diesel engine was supplied to the cylinder by compressed air from a compressor and ignited by compression. The efficiency of such an engine was approximately 30%.

It is interesting that a few years before Diesel, the Russian engineer Trinkler developed an engine running on crude oil in a mixed cycle - which is how all modern diesel engines operate, but it was not patented, and few people now know Trinkler’s name.

End of work -

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Internal combustion engines

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The role and application of internal combustion engines in construction
An internal combustion engine (ICE) is a piston heat engine in which the processes of fuel combustion, the release of heat and its conversion into mechanical work occur directly

Basic mechanisms and engine systems
The internal combustion engine consists of a crank mechanism, a gas distribution mechanism and five systems: power, ignition, lubrication, cooling and starting.

The crank mechanism is designed to
Theoretical and actual cycles

The nature of the working process in an engine can be different - heat supply (combustion) occurs at a constant volume (near TDC - these are carburetor engines) or at constant pressure

1.7.3. The compression process serves: 1 to expand the temperature limits between which the working process takes place;
2 to ensure the possibility of obtaining the maximum

Heat transfer during compression
During the initial period of compression after closing the intake valve or the purge and exhaust ports, the temperature of the charge filling the cylinder is lower than the temperature of the walls, head, and bottom of the piston. Therefore, in

Indicators of efficiency, economy and perfection of engine design
Indicative indicators: Fig. 20. Four-stroke indicator diagram

Exhaust gas toxicity indicators and methods for reducing toxicity
The starting materials in the combustion reaction are air containing approximately 85% carbon, 15% hydrogen and other gases and hydrocarbon fuel containing approximately 77% nitrogen, 23% acid

Flammability limits of air-fuel mixtures
Rice. 24. Combustion temperatures of gasoline-air combustible mixtures of different compositions: T

Combustion in carburetor engines
In carburetor engines, by the time the spark appears, the working mixture consisting of air, vapor or gaseous fuel and residual gases fills the compression volume. Process

Detonation
Features of the combustion process, Fig. 28: - fuel supply begins with an advance by an angle θ to TDC. and ends after v.m.t.;

- change in pressure from t.
Shapes of combustion chambers of diesel internal combustion engines

Undivided combustion chambers.
In undivided combustion chambers Fig. 29, the improvement in the process of fuel atomization and mixing with air has reached

Crank and gas distribution mechanisms
3.1. The crank mechanism (Fig. 33) is designed to sense gas pressure and convert the reciprocating motion of the piston into rotational motion of the crankshaft.

Supercharging, purpose and methods of supercharging
The supercharging of engine cylinders can be either dynamic or carried out using a special supercharger (compressor).

There are three systems of supercharging using superchargers: with p
Engine power systems

4.1 Diesel power system. The power supply system supplies fuel to the cylinders. At the same time, high power outputs must be ensured
Power supply system for carburetor engines

The preparation and supply of a combustible mixture to the cylinders of carburetor engines, the regulation of its quantity and composition is carried out by a power supply system, the operation of which has a great influence on
Contact-transistor ignition system

KTSZ began appearing on cars in the 60s. With an increase in the compression ratio, the use of leaner working mixtures and an increase in the crankshaft speed and the number of cylinders
Contactless transistor ignition system

BTSZ began to be used in the 80s. If in the KSZ the breaker directly opens the primary circuit, in the KTSZ - the control circuit, then in the BTSZ (Fig. 61-63) there is no breaker and the control becomes contactless
Microprocessor engine control systems

MSUDs began to be installed on cars from the mid-80s on passenger cars equipped with fuel injection systems.
The system controls the engine according to optimal characteristics and

Distributor cap
The outer surface of the distributor cap, as well as the ignition coil, must be kept clean. With tall “Zhiguli” covers, the flow of impulse along the outer surface onto the body is distributed Spark plug Spark plugs are used to generate the electric spark necessary to ignite the working mixture in the engine cylinders.

Lubrication, cooling and starting systems
Basic provisions. The engine lubrication system is designed to prevent increased wear, overheating and seizing of rubbing surfaces, and reduce the cost of indicators.

Cooling system
In piston engines, during the combustion of the working mixture, the temperature in the engine cylinders rises to 2000-28000 K. By the end of the expansion process, it decreases to 1000-1

Starting system
Starting piston engines pp., regardless of type and design, is carried out by rotating the engine crankshaft from outside source energy. In this case, the rotation speed should be about

Fuel
Engine fuels are products of crude oil refining (gasoline, diesel fuel) - The main part of it is hydrocarbons.

Gasoline is produced by condensing the light fractions of naphtha processing
Engine oil

7.3.1. Requirements for motor oils. In piston engines, oils of mainly petroleum origin are used to lubricate parts. The physicochemical properties of oils determine
Coolants

25-35% of the total heat is removed through the cooling system. The efficiency and reliability of the cooling system largely depends on the quality of the coolant. Cooling requirements

With

possession

Introduction……………………………………………………………………………….2

1. History of creation……………………………………………………………….…..3

3.1 2. History of the automotive industry in Russia…………………………7 ………………………………………….8

3. Piston internal combustion engines………………………8

ICE classification

3.2 Fundamentals of the design of piston internal combustion engines………………………9

3.3 Operating principle………………………………………………………..10

3.4 Operating principle of a four-stroke carburetor engine………………………………………………………………10 3.5 Operating principle of a four-stroke diesel engine……………11…………….12

3.6 Operating principle

two stroke engine 3.7 Operating cycle of four-stroke carburetor and diesel engines………………………………………….………….13………...……14

3.8 Duty cycle

four stroke engine

3.9 Duty cycles of two-stroke engines………………...15

Conclusion……………………………………………………………..16 Introduction. carry us across continents and oceans. And high above us, outside the earth's atmosphere, rockets and artificial Earth satellites fly. All this works with the help of electricity.

Man began his development with the appropriation of finished products of nature. Already at the first stage of development, he began to use artificial tools.

With the development of production, conditions begin to emerge for the emergence and development of machines. At first, machines, like tools, only helped man in his work. Then they began to gradually replace it.

In the feudal period of history, the power of water flow was used for the first time as a source of energy. The movement of water rotated the water wheel, which in turn powered various mechanisms. During this period, many different technological machines appeared. However, the widespread use of these machines was often hampered by the lack of nearby water flow. It was necessary to look for new sources of energy to power machines anywhere on the earth's surface. They tried wind energy, but it turned out to be ineffective.

They began to look for another source of energy. Inventors worked for a long time, tested many machines - and finally, new engine was built. It was a steam engine. It set in motion numerous machines and machines in factories and factories. At the beginning of the 19th century, the first land steam vehicles - steam locomotives - were invented.

But steam engines were complex, cumbersome and expensive installations. The rapidly developing mechanical transport needed a different engine - small and cheap. In 1860, the Frenchman Lenoir, using the structural elements of a steam engine, gas fuel and an electric spark for ignition, designed the first practical internal combustion engine.

1. HISTORY OF CREATION

Using internal energy means doing useful work using it, that is, converting internal energy into mechanical energy. In the simplest experiment, which consists of pouring some water into a test tube and bringing it to a boil (the test tube is initially closed with a stopper), the stopper, under the pressure of the resulting steam, rises up and pops out.

In other words, the energy of the fuel is converted into the internal energy of steam, and the steam, expanding, does work, knocking out the plug. This is how the internal energy of the steam is converted into the kinetic energy of the plug.

If the test tube is replaced with a strong metal cylinder, and the plug with a piston that fits tightly to the walls of the cylinder and is able to move freely along them, then you will get the simplest heat engine.

Heat engines are machines in which the internal energy of fuel is converted into mechanical energy.

The history of heat engines goes back a long way, they say, more than two thousand years ago, in the 3rd century BC, the great Greek mechanic and mathematician Archimedes built a cannon that fired using steam. A drawing of Archimedes' cannon and its description were found 18 centuries later in the manuscripts of the great Italian scientist, engineer and artist Leonardo da Vinci.

How did this gun fire? One end of the barrel was heated strongly over a fire. Then water was poured into the heated part of the barrel. The water instantly evaporated and turned into steam. The steam, expanding, ejected the core with force and roar. What is interesting for us here is that the cannon barrel was a cylinder along which the cannonball slid like a piston.

About three centuries later, in Alexandria, a cultural and wealthy city on the African coast of the Mediterranean Sea, the outstanding scientist Heron, whom historians call Heron of Alexandria, lived and worked. Heron left several works that have come down to us, in which he described various machines, devices, mechanisms known in those days.

In the writings of Heron there is a description of an interesting device, which is now called Heron's ball. It is a hollow iron ball fixed so that it can rotate around a horizontal axis. From a closed cauldron with boiling water, steam enters the ball through a tube; it escapes from the ball through curved tubes, and the ball begins to rotate. The internal energy of the steam is converted into mechanical energy of rotation of the ball. The Heron ball is a prototype of modern jet engines.

At that time, Heron's invention was not used and remained only fun. 15 centuries have passed. During the new flowering of science and technology that came after the Middle Ages, Leonardo da Vinci thought about using the internal energy of a couple. His manuscripts contain several drawings of a cylinder and a piston. There is water in the cylinder under the piston, and the cylinder itself is heated. Leonardo da Vinci assumed that the steam formed as a result of heating water, expanding and increasing in volume, would seek a way out and push the piston upward. During its upward movement, the piston could perform useful work.

Giovanni Branca, who lived during the century of the great Leonardo, imagined an engine using steam energy somewhat differently. It was a wheel with
blades, a jet of steam hit the second with force, causing the wheel to begin to rotate. Essentially, this was the first steam turbine.

In the 17th-18th centuries, the Englishmen Thomas Savery (1650-1715) and Thomas Newcomen (1663-1729), the Frenchman Denis Papin (1647-1714), the Russian scientist Ivan Ivanovich Polzunov (1728-1766) and others worked on the invention of the steam engine.

Papin built a cylinder in which a piston moved freely up and down. The piston was connected by a cable, thrown over a block, to a load, which, following the piston, also rose and fell. According to Papin, the piston could be connected to some machine, for example, a water pump, which would pump water. Popox was poured into the lower hinged part of the cylinder, which was then set on fire. The resulting gases, trying to expand, pushed the piston upward. After this, the cylinder and piston were doused with diode water from the outside. The gases in the cylinder cooled and their pressure on the piston decreased. The piston, under the influence of its own weight and external atmospheric pressure, moved downwards, lifting the load. The engine was doing useful work. For practical purposes, it was unsuitable: the technological cycle of its operation was too complicated (filling and igniting gunpowder, dousing with water, and this throughout the entire operation of the engine!). In addition, the use of such an engine was far from safe.

However, one cannot help but see in Palen’s first car the features of a modern internal combustion engine.

In his new engine, Papin used water instead of gunpowder. It was poured into the cylinder under the piston, and the cylinder itself was heated from below. The resulting steam lifted the piston. Then the cylinder was cooled, and the steam in it condensed and turned back into water. The piston, as in the case of a powder engine, fell down under the influence of its weight and atmospheric pressure. This engine worked better than a gunpowder engine, but it was also of little use for serious practical use: it was necessary to apply and remove fire, supply cooled water, wait for the steam to condense, turn off the water, etc.

All these disadvantages were due to the fact that the preparation of the steam necessary for the operation of the engine took place in the cylinder itself. But what if ready-made steam, obtained, for example, in a separate boiler, is introduced into the cylinder? Then it would be enough to alternately admit steam and cooled water into the cylinder, and the engine would work with higher speed and lower fuel consumption.

Denis Palen's contemporary, the Englishman Thomas Severi, guessed this and built a steam pump to pump water out of the mine. In his machine, steam was prepared outside the cylinder - in the boiler.

Following Severi, the English blacksmith Thomas Newcomen constructed a steam engine (also adapted for pumping water from a mine). He skillfully used much of what had been invented before him. Newcomen took a cylinder with a Papen piston, but received steam to lift the piston, like Severi, in a separate boiler.

Newcomen's machine, like all its predecessors, worked intermittently - there was a pause between two working strokes of the piston. It was the height of a four- to five-story building and, therefore, exclusively<прожорлива>: fifty horses barely had time to deliver fuel to her. The service personnel consisted of two people: the fireman continuously threw coal into the<ненасытную пасть>fireboxes, and the mechanic controlled the valves that let in steam and cold water into a cylinder.

Introduction

An internal combustion engine (ICE) is a type of engine heat engine, in which the chemical energy of the fuel (usually liquid or gaseous hydrocarbon fuel) burning in the working area is converted into mechanical work. Despite the fact that internal combustion engines are an imperfect type of heat engines ( loud noise, toxic emissions, shorter resource), due to its autonomy (the required fuel contains much more energy than the best electric batteries) ICEs are very widespread. Main disadvantage of internal combustion engines is what it produces high power only in a narrow rpm range. Therefore, the integral attributes of an internal combustion engine are the transmission and starter. Only in some cases (for example, in airplanes) can one do without a complex transmission. In addition, the internal combustion engine needs a fuel system (to supply the fuel mixture) and an exhaust system (to remove exhaust gases).

engine internal combustion car

History of the internal combustion engine

Nowadays, no one will be surprised by the use of an internal combustion engine. Millions of cars, gas generators and other devices use internal combustion engines (ICE) as a drive. The appearance of this type of engine in the 19th century was primarily due to the need to create an efficient and modern drive for various industrial devices and mechanisms. At that time, for the most part, a steam engine was used. It had a lot of disadvantages, for example, low coefficient useful action(i.e., most of the energy spent on steam production was simply wasted), was quite cumbersome, required qualified maintenance and a lot of time to start and stop. The industry needed a new engine devoid of these shortcomings. It became an internal combustion engine.

Back in the 17th century, the Dutch physicist Christian Hagens began experiments with internal combustion engines, and in 1680 a theoretical engine was developed, the fuel for which was black powder. However, the author’s ideas never came to fruition.

The first who managed to create the world's first working internal combustion engine was Nicéphore-Niepce. In 1806, he and his brother presented a report on new car, which “would be comparable in strength to steam, but would consume less fuel" The brothers named it "pyraeolophore". From Greek it can be translated as “dragged by the fiery wind.” It ran on coal dust, not gasoline or gas. At that time there was neither a gas nor an oil refining industry. The invention of pyraeophore aroused great interest. Two commissioners were tasked with investigating the invention. One of the commissioners was Lazare Carnot. Carnot gave positive feedback, even making it into the newspapers. Although the engine had a number of shortcomings, many of them could not be eliminated at that time due to the lack of necessary technologies: ignition of dust, for example, was carried out at atmospheric pressure, the distribution of the combustible substance inside the chamber was uneven, and the fit of the piston to the cylinder walls required improvement. In those days, the piston of a steam engine was considered to be fitted to the walls of the cylinder if a coin could hardly pass between them.

The brothers built an engine and equipped it with a three-meter boat weighing 450 kg in 1806. The boat went up the Sonya River at a speed twice the speed of the current.

Lazare Carnot had a son, Lieutenant of the General Staff Sadi Carnot, who in 1824 published a work in 200 copies that later immortalized his name. This is "Reflections on the motive force of fire and on machines capable of developing this force." In this book, he laid the foundations of thermodynamics - the theory for the development of internal combustion engines. The book mentioned the Niepce car, which may have prompted Sadi Carnot to think about the engines of the future - all internal combustion engines: gas, carburetor, and diesel. It also offers further improvements to the engine, ranging from air compression in the cylinder, etc.

Another quarter of a century would pass before the English physicist William Thomson (Lord Kelvin) and the German physicist Rudolf Clausius would revive Carnot's ideas and make thermodynamics a science. Nobody will remember Niepce at all. And the next internal combustion engine will appear only in 1858 from the Belgian engineer Jean Joseph Etienne Lenoir. Two-stroke electric carburetor engine, engine with spark ignition, fueled by coal gas, would be the first commercially successful engine of its kind. The first engine only worked for a few seconds due to the lack of a lubrication system and a cooling system, which were successfully used on subsequent samples. In 1863, Lenoir improved the design of his engine by using kerosene instead of gas fuel. It's a three-wheeled prototype modern cars drove a historic 50 miles.

The Lenoir engine was not without its drawbacks, its efficiency reached only 5%, it did not consume fuel and lubricants very efficiently, it got too hot, etc., but it was the first, after many years of oblivion, commercially successful project to create a new engine for industrial needs. In 1862, French scientist Alphonse Beau de Rojas proposed and patented the world's first four-cylinder engine. But it never got to the point of its creation, much less commercial production.

1864 - Austrian engineer Siegfried Marcus created the world's first single-cylinder carburetor engine powered by the combustion of crude oil. A few years later, the same scientist designed a vehicle that moved at a speed of 10 miles per hour.

1873 - George Brayton proposed a new design of a 2-cylinder carburetor kerosene engine, which later became a gasoline engine. It was the first safe model, but it was too massive and slow for commercial use.

1876 - Nicholas Otto, 14 years after the theoretical justification of the 4-cylinder engine by Rojas, created a working model known as the “Otto cycle,” a spark-ignition cycle. Otto's internal combustion engine had a vertical cylinder, the rotating shaft was located on its side, and a special rack was connected to the shaft. The shaft raised the piston, due to which a vacuum was formed, thanks to which the air-fuel mixture, which subsequently ignited. The engine did not use electric ignition; the engineers did not have a sufficient level of knowledge in electrical engineering; the mixture was ignited by an open flame through a special hole. After the explosion of the mixture, the pressure increased, under the influence of which the piston rose (first under the influence of gas, and then by inertia) and a special mechanism disconnected the rack from the shaft, a vacuum was created again, fuel was sucked into the combustion chamber, and the process was repeated again. The efficiency of this engine exceeded 15%, which was significantly higher than the efficiency of any steam engine of that time. Successful design, high efficiency, as well as constant work on the design of the unit (it was Otto who patented it in 1877 the new kind internal combustion engine with a four-stroke cycle, which underlies most modern internal combustion engines) made it possible to occupy a significant share of the drive market for various devices and mechanisms.

1883 - French engineer Edouard Delamare-Debotville designs a single-cylinder, four-stroke engine using gas as fuel. And although things never came to the practical implementation of the ideas, at least on paper Delamare-Debotville was ahead of Gottlieb Daimler and Karl Benz.

1885 - Gottlieb Daimler created what is today called the prototype of the modern gas engine - a device with vertically arranged cylinders and a carburetor. For these purposes, Daimler, together with his friend Wilhelm Maybach, purchased a workshop near the city of Stuttgart. The engine was created so that it could move the crew, so the requirements placed on it were very significant. The internal combustion engine had to be compact, have sufficient power and do not require a gas generator. “Reitwagen” - this is what the inventors called the first two-wheeled vehicle. A year later, the first prototype of the 4-X was presented to the world. wheeled car. Maybach developed an efficient carburetor that ensured efficient evaporation of fuel. At the same time, the Hungarian Banki patented a carburetor with a jet. Unlike its predecessors, the new carburetor proposed not to evaporate, but to atomize fuel, which evaporated directly in the engine cylinder. The carburetor also meters fuel and air and mixes them evenly in the required proportion. From the very beginning of his engineering career, Gottlieb Daimler was convinced that the steam engine was outdated and needed prompt replacement. Gas engines - this is where Daimler saw the development prospects. He had to knock on many doors of companies that did not want to take risks and invest money in a product that was still unknown to them. Maybach, the first person who understood him, later became his friend and partner. In 1872, Daimler, together with Nicholas Otto, gathered all the best specialists with whom he had ever worked, led by Maybach. The task was formulated as follows: to create a functional and efficient gas engine. And two years later, this task was completed, and engine production was put into production. Two engines a day is a huge speed by those standards. But here the positions of Daimler and Otto on the further development of the company begin to diverge. The first believes that it is necessary to improve the design and conduct a series of studies, the second speaks of the need to increase the production of already designed engines. Due to these contradictions, Daimler left the company, followed by Maybach. In 1889, they organized the DaimlerMotorenGesellschaft company, the first car rolled off its assembly line. And twelve years later, Maybach assembled the first Mercedes car, named after his daughter, which would later become a legend.

1886 - January 29 Karl Benz patented the design of the world's first three-wheeled gas car with electric ignition, differential and water cooling. Energy was supplied to the wheels using a special pulley and belt attached to the transmission shaft. In 1891, he also built a 4-wheeled vehicle. It was Karl Benz who was the first who managed to combine chassis and engine together. Already in 1893, Benz cars became the world's first cheap mass-produced vehicles. In 1903, Benz&Company merged with Daimler, forming Daimler-Benz and later Mercedes-Benz, and Benz himself became a member of the supervisory board until he died in 1929. 1889 - Daimler improved his four-stroke engine, introducing a V-shaped cylinder arrangement and the use of valves, greatly increasing the engine's power-to-weight ratio.

This was the path of development of internal combustion engines, which brought comfort and speed of movement into our lives. Time will tell about the further development of this direction, but designers are already offering quite interesting alternative options for the design of internal combustion engines.

25-35% of the total heat is removed through the cooling system. The efficiency and reliability of the cooling system largely depends on the quality of the coolant. Cooling requirements

With

possession

Introduction……………………………………………………………………………….2

1. History of creation……………………………………………………………….…..3

3.1 Classification of internal combustion engines…………………………………….8

3. Piston internal combustion engines………………………8

ICE classification

3.2 Fundamentals of the design of piston internal combustion engines………………………9

3.3 Operating principle………………………………………………………..10

3.6 Operating principle of a two-stroke engine…………….12

3.6 Operating principle

3.8 Duty cycle of a four-stroke engine………………14

3.8 Duty cycle

four stroke engine

3.9 Duty cycles of two-stroke engines………………...15

The 20th century is the world of technology. Mighty machines extract millions of tons of coal, ore, and oil from the depths of the earth. Powerful power plants generate billions of kilowatt-hours of electricity. Thousands of factories and factories produce clothing, radios, televisions, bicycles, cars, watches and other necessary products. Telegraph, telephone and radio connect us with the whole world. Trains, ships, and planes carry us across continents and oceans at high speed. And high above us, outside the earth's atmosphere, rockets and artificial Earth satellites fly. All this works with the help of electricity.

Man began his development with the appropriation of finished products of nature. Already at the first stage of development, he began to use artificial tools.

They began to look for another source of energy. The inventors worked for a long time, tested many machines - and finally, a new engine was built. It was a steam engine. It set in motion numerous machines and machines in factories and factories. At the beginning of the 19th century, the first land steam vehicles - steam locomotives - were invented.

But steam engines were complex, bulky and expensive installations. The rapidly developing mechanical transport needed a different engine - small and cheap. In 1860, the Frenchman Lenoir, using the structural elements of a steam engine, gas fuel and an electric spark for ignition, designed the first practical internal combustion engine.

1. HISTORY OF CREATION

Heat engines are machines in which the internal energy of fuel is converted into mechanical energy.

However, one cannot help but see in Palen’s first car the features of a modern internal combustion engine.

All these disadvantages were due to the fact that the preparation of the steam necessary for the operation of the engine took place in the cylinder itself. But what if ready-made steam, obtained, for example, in a separate boiler, is introduced into the cylinder? Then it would be enough to alternately introduce steam and cooled water into the cylinder, and the engine would operate at higher speeds and with less fuel consumption.

Denis Palen's contemporary, the Englishman Thomas Severi, guessed this and built a steam pump to pump water out of the mine. In his machine, steam was prepared outside the cylinder - in the boiler.

Newcomen's machine, like all its predecessors, worked intermittently - there was a pause between two working strokes of the piston. It was the height of a four- to five-story building and, therefore, exclusively<прожорлива>: fifty horses barely had time to deliver fuel to her. The service personnel consisted of two people: the fireman continuously threw coal into the<ненасытную пасть>fireboxes, and the mechanic operated the valves that admitted steam and cold water into the cylinder.

It took another 50 years before a universal steam engine was built. This happened in Russia, on one of its remote outskirts - Altai, where at that time the brilliant Russian inventor, soldier's son Ivan Polzunov, was working.

Polzunov built his<огнедействующую машину>at one of the Barnaul factories. This invention was his life's work and, one might say, cost him his life. In April 1763, Polzunov completed his calculations and submitted the project for consideration. Unlike the Severi and Newcomen steam pumps, which Polzunov knew about and the shortcomings of which he clearly recognized, this was a project for a universal machine continuous action. The machine was intended for blowing bellows, pumping air into smelting furnaces. Its main feature was that the working shaft swung continuously, without idle pauses. This was achieved by the fact that Polzunov provided, instead of one Cylinder, as was the case in Newcomen’s machine, two working alternately. While in one cylinder the piston rose upward under the influence of steam, in the other the steam condensed and the piston went down. Both pistons were connected by one working shaft, which they alternately turned in one direction or the other. The working stroke of the machine was carried out not due to atmospheric pressure, like Newcomen, but due to the work of steam in the cylinders.

In the spring of 1766, Polzunov's students, a week after his death (he died at 38), tested the machine. It worked for 43 days and set in motion the bellows of three smelting furnaces. Then the boiler started leaking; the leather with which the pistons were covered (to reduce the gap between the cylinder wall and the piston) wore out, and the car stopped forever. No one else was working on it.

The creator of another universal steam engine who became widespread was the English mechanic James Watt (1736-1819). Working to improve Newcomen's machine, in 1784 he built an engine that was suitable for any need. Watt's invention was received with a bang. In the most developed countries of Europe, manual labor in factories and factories was increasingly replaced by machine work. A universal engine became necessary for production, and it was created.

Watt's engine uses the so-called crank mechanism, which converts the reciprocating motion of the piston into
rotational movement of the wheel.

It was only later that it was invented<двойное действие>machines: by alternately directing steam under the piston and then on top of the piston, Watt turned both of its strokes (up and down) into working ones. The car has become more powerful. Steam was directed to the upper and lower parts of the cylinder by a special steam distribution mechanism, which was subsequently improved and named<золотником>.

Watt then came to the conclusion that it was not at all necessary to supply steam to the cylinder all the time the piston was moving. It is enough to let some portion of steam into the cylinder and give the piston movement, and then this steam will begin to expand and move the piston to its extreme position. This made the car more economical: less steam was required, less fuel was consumed.

Today, one of the most common heat engines is the internal combustion engine (ICE). It is installed on cars, ships, tractors, motor boats etc., there are hundreds of millions of such engines around the world.

For rate heat engine It is important to know how much of the energy released by the fuel is converted into useful work. The greater this part of the energy, the more economical the engine.

To characterize efficiency, the concept of efficiency factor (efficiency) is introduced.

The efficiency of a heat engine is the ratio of that part of the energy that went into performing useful work of the engine to the total energy released during fuel combustion.

The first diesel engine (1897) had an efficiency of 22%. Watt's steam engine (1768) - 3-4%, modern stationary diesel has an efficiency of 34-44%.

2. HISTORY OF AUTOMOBILE BUILDING IN RUSSIA

Road transport in Russia serves all sectors of the national economy and occupies one of the leading places in the country's unified transport system. Per share road transport accounts for over 80% of cargo transported by all modes of transport combined, and more than 70% of passenger traffic.

Road transport was created as a result of development new industry national economy - the automotive industry, which at the present stage is one of the main links in the domestic mechanical engineering.

The creation of a car began more than two hundred years ago (the name “car” comes from the Greek word autos - “self” and the Latin mobilis - “mobile”), when they began to produce “self-propelled” carts. They first appeared in Russia. In 1752, a self-taught Russian mechanic, peasant L. Shamshurenkov, created a “self-running stroller”, quite perfect for its time, driven by the power of two people. Later, the Russian inventor I.P. Kulibin created a “scooter cart” with a pedal drive. With the advent of the steam engine, the creation of self-propelled carriages advanced rapidly. In 1869-1870 J. Cugnot in France, and a few years later in England, steam cars were built. The widespread use of the automobile as a means of transport began with the advent of the high-speed internal combustion engine. In 1885, G. Daimler (Germany) built a motorcycle with gasoline engine, and in 1886 K. Benz - a three-wheeled cart. Around the same time, cars with internal combustion engines were created in industrialized countries (France, Great Britain, USA).

At the end of the 19th century, the automobile industry emerged in a number of countries. In tsarist Russia, attempts were made repeatedly to organize their own mechanical engineering. In 1908, car production was organized at the Russian-Baltic Carriage Works in Riga. For six years, cars were produced here, assembled mainly from imported parts. In total the plant built 451 a car and a small number of trucks. In 1913, the automobile fleet in Russia amounted to about 9,000 cars, most of them foreign-made.

After the Great October Socialist Revolution, we had to create a domestic automotive industry. The beginning of the development of the Russian automotive industry dates back to 1924, when the first AMO-F-15 trucks were built in Moscow at the AMO plant.

During the period 1931-1941. large-scale and mass production of cars is being created. In 1931, mass production of trucks began at the AMO plant. In 1932, the GAZ plant went into operation.

Started production in 1940 small cars Moscow plant of small cars. Somewhat later, the Ural Automobile Plant was created. During the years of the post-war five-year plans, Kutaisi, Kremenchug, Ulyanovsk, and Minsk automobile plants came into operation. Since the late 60s, the development of the automotive industry has been characterized by a particularly rapid pace. In 1971, the Volzhsky Automobile Plant named after. 50th anniversary of the USSR.

As mentioned above, thermal expansion is used in internal combustion engines. But how is it used and what function does it perform? We will look at the example of work piston internal combustion engine. An engine is an energy-power machine that converts any energy into mechanical work. Engines in which mechanical work is created as a result of the conversion of thermal energy are called thermal. Thermal energy is obtained by burning any fuel. A heat engine in which part of the chemical energy of the fuel burning in the working cavity is converted into mechanical energy is called a piston internal combustion engine. (Soviet encyclopedic dictionary)

As mentioned above, as power plants for cars greatest distribution taught internal combustion engines, in which the process of fuel combustion with the release of heat and its conversion into mechanical work occurs directly in the cylinders. But in most modern cars internal combustion engines are installed, which are classified according to various criteria: According to the method of mixture formation - engines with external mixture formation, in which the combustible mixture is prepared outside the cylinders (carburetor and gas), and engines with internal mixture formation (the working mixture is formed inside the cylinders) - diesel engines; According to the method of implementing the working cycle - four-stroke and two-stroke; By the number of cylinders - single-cylinder, double-cylinder and multi-cylinder; According to the arrangement of the cylinders - engines with a vertical or inclined arrangement of cylinders in one row, V-shaped with the arrangement of the cylinders at an angle (with the arrangement of the cylinders at an angle of 180, the engine is called an engine with opposing cylinders, or opposed); According to the cooling method - for engines with liquid or air cooled; By type of fuel used - gasoline, diesel, gas and multi-fuel; By compression ratio. Depending on the degree of compression, there are

high (E=12...18) and low (E=4...9) compression engines; According to the method of filling the cylinder with a fresh charge: a) naturally aspirated engines, in which the intake of air or a combustible mixture is carried out due to the vacuum in the cylinder during the suction stroke of the piston;) supercharged engines, in which the intake of air or a combustible mixture into the working cylinder occurs under pressure, created by the compressor, in order to increase the charge and obtain increased power engine; By rotation speed: low-speed, high-speed, high-speed; By purpose, engines are distinguished between stationary, auto-tractor, marine, diesel locomotive, aviation, etc.

Piston internal combustion engines consist of mechanisms and systems that perform their assigned functions and interact with each other. The main parts of such an engine are the crank mechanism and gas distribution mechanism, as well as power, cooling, ignition and lubrication systems.

The crank mechanism converts the linear reciprocating motion of the piston into rotational motion of the crankshaft.

The gas distribution mechanism ensures timely admission of the combustible mixture into the cylinder and removal of combustion products from it.

The power system is designed to prepare and supply the combustible mixture to the cylinder, as well as to remove combustion products.

The lubrication system serves to supply oil to interacting parts in order to reduce the friction force and partially cool them; at the same time, the circulation of oil leads to washing away carbon deposits and removing wear products.

The cooling system maintains normal temperature regime engine operation, ensuring heat removal from cylinder parts that are very hot during combustion of the working mixture piston group and valve mechanism.

The ignition system is designed to ignite the working mixture in the engine cylinder.

So, a four-stroke piston engine consists of a cylinder and a crankcase, which is covered at the bottom with a sump. A piston with compression (sealing) rings moves inside the cylinder, having the shape of a glass with a bottom in the upper part. The piston is connected through the piston pin and connecting rod to the crankshaft, which rotates in the main bearings located in the crankcase. The crankshaft consists of main journals, cheeks and a connecting rod journal. Cylinder, piston, connecting rod and crankshaft make up the so-called crank mechanism. The top of the cylinder is covered with a head with valves, the opening and closing of which is strictly coordinated with the rotation of the crankshaft, and therefore with the movement of the piston.

The movement of the piston is limited to two extreme positions at which its speed is zero. The uppermost position of the piston is called top dead point (TDC), its lowest position is bottom dead center (BDC).

Non-stop movement of the piston through dead spots is provided by a flywheel shaped like a disk with a massive rim. The distance traveled by the piston from TDC to BDC is called the piston stroke S, which is equal to twice the radius R of the crank: S=2R.

The space above the bottom of the piston when it is at TDC is called the combustion chamber; its volume is denoted by Vc; cylinder space between two dead spots(BDC and TDC) is called its displacement and is designated Vh. The sum of the combustion chamber volume Vс and the working volume Vh is the total volume of the cylinder Va: Va=Vс+Vh. The working volume of the cylinder (it is measured in cubic centimeters or meters): Vh=пД^3*S/4, where D is the diameter of the cylinder. The sum of all working volumes of the cylinders of a multi-cylinder engine is called the engine working volume, it is determined by the formula: Vр=(пД^2*S)/4*i, where i is the number of cylinders. The ratio of the total volume of the cylinder Va to the volume of the combustion chamber Vc is called the compression ratio: E=(Vc+Vh)Vc=Va/Vc=Vh/Vc+1. The compression ratio is important parameter internal combustion engines, because greatly affects its efficiency and power.

Action piston engine internal combustion is based on the use of the work of thermal expansion of heated gases during the movement of the piston from TDC to BDC. Heating of gases in the TDC position is achieved as a result of combustion of fuel mixed with air in the cylinder. This increases the gas temperature and pressure. Since the pressure under the piston is equal to atmospheric pressure, and in the cylinder it is much greater, then under the influence of the pressure difference the piston will move down, while the gases will expand, doing useful work. This is where the thermal expansion of gases makes itself felt, and this is where its technological function lies: pressure on the piston. In order for the engine to constantly produce mechanical energy, the cylinder must be periodically filled with new portions of air through the intake valve and fuel through the injector, or a mixture of air and fuel must be supplied through the intake valve. The products of fuel combustion after their expansion are removed from the cylinder through the inlet valve. These tasks are performed by the gas distribution mechanism, which controls the opening and closing of the valves, and the fuel supply system.

The engine operating cycle is a periodically repeating series of sequential processes occurring in each cylinder of the engine and causing the conversion of thermal energy into mechanical work. If the working cycle is completed in two strokes of the piston, i.e. per revolution of the crankshaft, then such an engine is called a two-stroke engine.

Car engines typically operate on a four-stroke cycle, which is completed in two revolutions of the crankshaft or four strokes of the piston and consists of intake, compression, expansion (power stroke) and exhaust strokes.

In a carburetor four-stroke single-cylinder engine, the operating cycle occurs as follows:

1. Intake Stroke As the engine crankshaft makes its first half revolution, the piston moves from TDC to BDC, the intake valve is open, the exhaust valve is closed. A vacuum of 0.07 - 0.095 MPa is created in the cylinder, as a result of which a fresh charge of the combustible mixture, consisting of gasoline vapor and air, is sucked through the inlet gas pipeline into the cylinder and, mixing with residual exhaust gases, forms a working mixture.

2. Compression stroke. After filling the cylinder with the combustible mixture, with further rotation of the crankshaft (second half-turn), the piston moves from BDC to TDC with the valves closed. As the volume decreases, the temperature and pressure of the working mixture increase.

3. Expansion stroke or power stroke. At the end of the compression stroke, the working mixture is ignited by an electric spark and quickly burns, as a result of which the temperature and pressure of the resulting gases increases sharply, while the piston moves from TDC to BDC. During the expansion stroke, the connecting rod pivotally connected to the piston makes complex movement and through the crank causes the crankshaft to rotate. When expanding, gases perform useful work, so the piston stroke during the third half-turn of the crankshaft is called the power stroke. At the end of the piston's working stroke, when it is near BDC, the exhaust valve opens, the pressure in the cylinder decreases to 0.3 -0.75 MPa, and the temperature to 950 - 1200 C. 4. Exhaust stroke. During the fourth half revolution of the crankshaft, the piston moves from BDC to TDC. In this case, the exhaust valve is open, and combustion products are pushed out of the cylinder into the atmosphere through the exhaust gas pipeline.

In a four-stroke engine, the working processes occur as follows:

1. Intake stroke. When the piston moves from TDC to BDC, due to the resulting vacuum, atmospheric air enters the cylinder cavity through the open intake valve. The air pressure in the cylinder is 0.08 - 0.095 MPa, and the temperature is 40 - 60 C.

2. Compression stroke. The piston moves from BDC to TDC; The intake and exhaust valves are closed, as a result of which the upward moving piston compresses the incoming air. For fuel to ignite, the temperature of the compressed air must be higher than the auto-ignition temperature of the fuel. As the piston moves to TDC, diesel fuel is injected into the cylinder through the nozzle, supplied by the fuel pump.

3. Expansion stroke, or power stroke. The fuel injected at the end of the compression stroke, mixed with heated air, ignites, and the combustion process begins, characterized by a rapid increase in temperature and pressure. At the same time, the maximum

the gas pressure reaches 6 - 9 MPa, and the temperature 1800 - 2000 C. Under the influence of gas pressure, piston 2 moves from TDC to BDC - a working stroke occurs. Near BDC, the pressure drops to 0.3 - 0.5 MPa, and the temperature to 700 - 900 C.

4. Release stroke. The piston moves from BDC to TDC and through the open exhaust valve 6, the exhaust gases are pushed out of the cylinder. The gas pressure decreases to 0.11 - 0.12 MPa, and the temperature to 500-700 C. After the end of the exhaust stroke, with further rotation of the crankshaft, the working cycle is repeated in the same sequence. For generalization, diagrams of the operating cycle of carburetor engines and diesel engines are shown.

Two-stroke engines differ from four-stroke engines in that the cylinders are filled with a combustible mixture or air at the beginning of the compression stroke, and the cylinders are cleaned of exhaust gases at the end of the expansion stroke, i.e. the exhaust and intake processes occur without independent piston strokes. General process for all types of two-stroke

engines - purging, i.e. the process of removing exhaust gases from the cylinder using a stream of combustible mixture or air. Therefore, this type of engine has a compressor (purge pump). Let's consider the operation of a two-stroke carburetor engine with crank-chamber purge. This type of engine does not have valves; their role is played by a piston, which, when moving, closes the intake, exhaust and purge windows. Through these windows, the cylinder at certain moments communicates with the intake and exhaust pipelines and the crank chamber (crankcase), which does not have direct communication with the atmosphere. The cylinder in the middle part has three windows: inlet, exhaust 6 and purge, which is connected by a valve to the crank chamber of the engine.

The working cycle in the engine is carried out in two strokes:

1. Compression stroke. The piston moves from BDC to TDC, blocking first the purge and then the outlet 6 window. After the piston closes the exhaust window in the cylinder, compression of the combustible mixture that previously entered it begins. At the same time, due to its tightness, a vacuum is created in the crank chamber, under the influence of which a combustible mixture enters the crank chamber from the carburetor through the open inlet window.

2. Power stroke. When the piston is positioned near TDC, the compressed working mixture is ignited by an electric spark from the spark plug, as a result of which the temperature and pressure of the gases increase sharply. Under the influence of thermal expansion of gases, the piston moves to BDC, while the expanding gases perform useful work. At the same time, the descending piston closes the inlet window and compresses the combustible mixture in the crank chamber.

When the piston reaches the exhaust window, it opens and exhaust gases begin to be released into the atmosphere, the pressure in the cylinder decreases. With further movement, the piston opens the purge window and the combustible mixture compressed in the crank chamber flows through the channel, filling the cylinder and purging it of exhaust gas residues.

Duty cycle of two-stroke diesel engine differs from the operating cycle of a two-stroke carburetor engine in that in a diesel engine air, rather than a combustible mixture, enters the cylinder, and at the end of the compression process finely atomized fuel is injected.

The power of a two-stroke engine with the same cylinder dimensions and shaft speed is theoretically twice that of a four-stroke engine due to the greater number of operating cycles. However, incomplete use of the piston stroke for expansion, poorer release of the cylinder from residual gases and the expenditure of part of the generated power on driving the purge compressor lead to an increase in power by only 60...70%.

The work cycle of a four-stroke engine consists of five processes: intake, compression, combustion, expansion and exhaust, which occur in four strokes or two revolutions of the crankshaft.

A graphical representation of the gas pressure as the volume in the engine cylinder changes during each of the four cycles is provided by an indicator diagram. It can be built according to thermal calculation data or removed while the engine is running using a special device - an indicator.

Intake process. The combustible mixture is admitted after exhaust gases from the previous cycle are released from the cylinders. The intake valve opens with some advance before TDC in order to obtain a larger flow area at the valve by the time the piston reaches TDC. The intake of the combustible mixture is carried out in two periods. In the first period, the mixture enters when the piston moves from TDC to BDC due to the vacuum created in the cylinder. In the second period, the mixture is injected when the piston moves from BDC to TDC for some time, corresponding to 40 - 70 rotations of the crankshaft due to the pressure difference and the velocity pressure of the mixture. The intake of the combustible mixture ends with the closing of the intake valve. The combustible mixture entering the cylinder is mixed with residual gases from the previous cycle and forms a combustible mixture. The mixture pressure in the cylinder during the intake process is 70 - 90 kPa and depends on the hydraulic losses in the engine intake system. The temperature of the mixture at the end of the intake process rises to 340 - 350 K due to its contact with heated engine parts and mixing with

residual gases having a temperature of 900 - 1000 K.

Compression process. Compression of the working mixture in the engine cylinder occurs when the valves are closed and the piston moves. The compression process occurs in the presence of heat exchange between the working mixture and the walls (cylinder, head and piston bottom). At the beginning of compression, the temperature of the working mixture is lower than the temperature of the walls, so heat is transferred to the mixture from the walls. As compression continues, the temperature of the mixture rises and becomes higher than the temperature of the walls, so heat from the mixture is transferred to the walls. Thus, the compression process is carried out using a polytrope, average which n=1.33...1.38. The compression process ends at the moment the working mixture ignites. The pressure of the working mixture in the cylinder at the end of compression is 0.8 - 1.5 MPa, and the temperature is 600 - 750 K.

Combustion process. Combustion of the working mixture begins before the piston reaches TDC, i.e. when a compressed mixture is ignited by an electric spark. After ignition, the flame front of a burning candle from the candle spreads throughout the entire volume of the combustion chamber at a speed of 40 - 50 m/s. Despite such a high combustion rate, the mixture manages to burn out during the time until the crankshaft turns 30 - 35. When the working mixture burns, a large amount of heat is released in the area corresponding to 10 - 15 before TDC and 15 - 20 after BDC, resulting in pressure and the temperature of the gases formed in the cylinder increases rapidly. At the end of combustion, the gas pressure reaches 3 - 5 MPa, and the temperature 2500 - 2800 K.

Expansion process. Thermal expansion of the gases in the engine cylinder occurs after the end of the combustion process when the piston moves to BDC. When gases expand, they do useful work. The process of thermal expansion occurs with intense heat exchange between gases and walls (cylinder, head and piston bottom). At the beginning of expansion, the working mixture burns out, as a result of which the resulting gases receive heat. Gases give off heat to the walls during the entire process of thermal expansion. The temperature of the gases decreases during the expansion process, therefore, the temperature difference between the gases and the walls changes. Thermal expansion process ending at the moment of opening exhaust valve,. The process of thermal expansion occurs along a polymeter, the average of which is n2 = 1.23...1.31. The gas pressure in the cylinder at the end of expansion is 0.35 -0.5 MPa, and the temperature is 1200 - 1500 K.

Release process. The release of exhaust gases begins when the exhaust valve opens, i.e. 40 - 60 before the piston reaches BDC. The release of gases from the cylinder is carried out in two periods. In the first period, gases are released when the piston moves to BDC due to the fact that the gas pressure in the cylinder is significantly higher than atmospheric pressure. During this period, about 60% of the exhaust gases are removed from the cylinder at a speed of 500 - 600 m/s. In the second period, gases are released when the piston moves from BDC to the closing of the exhaust valve due to the pushing action of the piston and the inertia of the moving gases. The release of exhaust gases ends at the moment the exhaust valve closes, i.e. 10 - 20 after the piston reaches TDC. The gas pressure in the cylinder during the ejection process is 0.11 - 0.12 MPa, the gas temperature at the end of the ejection process is 90 - 1100 K.

The working cycle of a diesel engine differs significantly from the working cycle of a carburetor engine in the way the working mixture is formed and ignited.

Intake process. Air intake starts when the intake is open

valve and ends when it closes. The air intake process occurs in the same way as the intake of a combustible mixture in a carburetor engine. The air pressure in the cylinder during the intake process is 80 - 95 kPa and depends on the hydraulic losses in the engine intake system. The air temperature at the end of the exhaust process rises to 320 - 350 K due to its contact with heated engine parts and mixing with residual gases.

Compression process. Compression of the air in the cylinder begins after closing the intake valve and ends at the moment of fuel injection into the combustion chamber. The air pressure in the cylinder at the end of compression is 3.5 - 6 MPa, and the temperature is 820 - 980 K.

Combustion process. Fuel combustion begins from the moment fuel is supplied to the cylinder, i.e. 15 - 30 before the piston reaches TDC. At this moment, the temperature of the compressed air is 150 - 200 C higher than the auto-ignition temperature. fuel entering the cylinder in a finely atomized state does not ignite instantly, but with a delay of some time (0.001 - 0.003 s), called the ignition delay period. During this period, the fuel warms up, mixes with air and evaporates, i.e. a working mixture is formed. The prepared fuel ignites and burns. At the end of combustion, the gas pressure reaches 5.5 - 11 MPa, and the temperature 1800 - 2400 K.

Expansion process. Thermal expansion of the gases in the cylinder begins after the combustion process ends and ends when the exhaust valve closes. At the beginning of expansion, fuel burns out. The process of thermal expansion proceeds similarly to the process of thermal expansion of gases in a carburetor engine. The gas pressure in the cylinder at the end of expansion is 0.3 - 0.5 MPa, and the temperature is 1000 - 1300 K.

Release process. The release of exhaust gases begins when the exhaust valve opens and ends when the exhaust valve closes. The process of releasing exhaust gases occurs in the same way as the process of releasing gases in a carburetor engine. The gas pressure in the cylinder during the ejection process is 0.11 - 0.12 MPa, the gas temperature at the end of the ejection process is 700 - 900 K.

The working cycle of a two-stroke engine is completed in two strokes, or one revolution of the crankshaft. Let's consider the working cycle of a two-stroke carburetor engine with crank-chamber scavenging,

The process of compression of the combustible mixture located in the cylinder begins from the moment the piston closes the cylinder windows when the piston moves from BDC to TDC. The compression process proceeds in the same way as in a four-stroke carburetor engine,

The combustion process is similar to the combustion process in a four-stroke carburetor engine.

The process of thermal expansion of gases in the cylinder begins after the end of the combustion process and ends when the exhaust windows open. The process of thermal expansion occurs similarly to the process of expansion of gases in a four-stroke carburetor engine. The process of exhaust gases begins when the exhaust ports are opened, i.e. 60 - 65 before the piston reaches BDC, and ends 60 - 65 after the piston passes BDC, shown on the diagram by line 462. As the exhaust window opens, the pressure in the cylinder decreases sharply, and 50 - 55 before the piston reaches BDC, the purge windows open and the combustible mixture, which previously entered the crank chamber and was compressed by the descending piston, begins to enter the cylinder. The period during which

two processes occur simultaneously - the intake of the combustible mixture and the release of exhaust gases - called purge. During purging, the combustible mixture displaces the exhaust gases and is partially carried away along with them. With further movement to TDC, the piston first blocks the purge ports, stopping the access of the combustible mixture into the cylinder from the crank chamber, and then the exhaust ports, and the compression process begins in the cylinder.

So, we see that internal combustion engines are a very complex mechanism. And the function performed by thermal expansion in internal combustion engines is not as simple as it seems at first glance. And internal combustion engines would not exist without the use of thermal expansion of gases. And we are easily convinced of this by examining in detail the operating principle of internal combustion engines, their operating cycles - all their work is based on the use of thermal expansion of gases. But internal combustion engines are only one specific application of thermal expansion. And judging by the benefits thermal expansion brings to people through an internal combustion engine, one can judge the benefits of this phenomenon in other areas of human activity.

And let the era of the internal combustion engine pass, let them have many shortcomings, let new engines appear that do not pollute the internal environment and do not use the thermal expansion function, but the first ones will benefit people for a long time, and people will speak kindly of them after many hundreds of years about them, because they brought humanity to a new level of development, and, having passed it, humanity rose even higher.