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HISTORY OF TECHNOLOGY, TECHNOLOGY, OBJECTS AROUND US
The engine is gas and petrol. History of invention and production
Directory / The history of technology, technology, objects around us Internal combustion engine - an engine in which fuel burns directly in the working chamber (inside) of the engine. The internal combustion engine converts the pressure from fuel combustion into mechanical work.
The steam engine did not completely solve the energy problem facing humanity. Small workshops and enterprises, which in the 10th century constituted a large part of the industrial sector, were not always able to use it. The fact is that a small steam engine had a very low efficiency (less than XNUMX%). In addition, the use of such an engine was associated with high costs and troubles. In order to put it into motion, it was necessary to build a fire and induce steam. Even if the car was needed only at times, it still had to be constantly kept under steam. Small industry required an engine of small power, taking up little space, which could be turned on and off at any time without much preparation. For the first time, the idea of such an engine was proposed at the very beginning of the XNUMXth century. In the last year of the 1799th century, the French engineer Philippe Lebon discovered lighting gas. Tradition attributes its success to chance - Lebon saw the gas flare up, flowing from a vessel with sawdust put on fire, and realized what benefit could be derived from this phenomenon. In XNUMX, he received a patent for the use and method of obtaining lighting 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, lighting gas was suitable not only for lighting. 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 when ignited, releasing a large amount of heat. The products of combustion rapidly expanded, exerting strong pressure on the environment. By creating the appropriate conditions, it is possible to use the released energy in the interests of man. The Lebon engine had two compressors and a mixing chamber. One compressor was supposed to pump compressed air into the chamber, and the other - compressed light gas from the gas generator. The gas-air mixture then entered the working cylinder, where it ignited. The engine was double-acting, that is, the working chambers were alternately acting on both sides of the piston.
In essence, Le Bon nurtured the idea of an internal combustion engine, but in 1804 he died before he could bring his invention to life. But his idea continued to attract the closest attention. Indeed, the principle of operation of a gas engine is much simpler than that of a steam engine, since here the fuel itself directly produces pressure on the piston, while in a steam engine, thermal energy is first transferred to another carrier - water vapor, which does useful work. In subsequent years, several inventors from different countries tried to create a workable engine using lighting gas. 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 at an electroplating plant, Lenoir came up with the idea that the air-fuel mixture in a gas engine could be ignited with an electric spark, and decided to build an engine based on this idea. The owner of the electroplating workshop provided Lenoir with money, with which he built his first engine in 1860. Both in appearance and in design, it resembled a steam engine. The engine was double acting. The lower spool alternately supplied air and gas to the cylinder cavities located on opposite sides of the piston. The upper spool served to release exhaust gases. Gas and air were supplied to the spool through separate channels. The mixture was sucked into each cavity until about half the stroke, after which the spool closed the inlet window, and the mixture was ignited by an electric spark. Burning, it expanded and acted on the piston, producing useful work. After the end of the reaction, the second spool communicated the cylinder with the exhaust pipe. Meanwhile, the mixture was ignited on the other side of the piston. He began to move back, displacing the exhaust gases. Lenoir was not immediately successful. After it was possible to make all the parts and assemble the machine, it worked for 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 launch attempt also ended in failure due to poor piston stroke. Lenoir supplemented his design with a lubrication system. Only then did the engine start running.
After the announcement of this invention, the workshop began to receive orders for a new engine, but its work continued to be unsatisfactory - the ignition system often malfunctioned, the spool did not work without lubrication, and it was not possible to establish its satisfactory lubrication at a temperature of 800 degrees. The efficiency of the engine barely reached 4%, it consumed a huge amount of lubricant and gas. Nevertheless, the engine quickly gained popularity. Its main buyers were small enterprises (printing houses, repair shops, etc.), for which steam engines were too expensive and bulky. Meanwhile, the Lenoir engine turned out to be easy to operate, light and had small dimensions. In 1864, more than 300 such engines of various capacities were already produced. Having grown rich, Lenoir stopped working on improving his car, and this predetermined her fate - she was forced out of the market by a more advanced 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 an agreement with the wealthy engineer Langen to exploit this invention. Soon the firm "Otto and Company" was created.
At first glance, the Otto engine represented a step backwards from the Lenoir engine. The cylinder was vertical. The rotating shaft was placed above the cylinder on the side. Along the axis of the piston, a rail connected to the shaft was attached to it. The engine worked as follows. The rotating shaft raised the piston by 1/10 of the height of the cylinder, as a result of which a rarefied space formed under the piston and a mixture of air and gas was sucked in. The mixture then ignited. Neither Otto nor Langen had sufficient knowledge of electrical engineering and abandoned electric ignition. They ignited with an open flame through a tube. During the explosion, the pressure under the piston increased to approximately 4 atm. Under the influence of this pressure, the piston rose, the volume of gas increased and the pressure fell. 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 burnt fuel was used in the engine with maximum completeness. 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 pressure, the exhaust valve opened, and the piston displaced the exhaust gases with its mass. Due to the more complete expansion of the 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 of that time. The most difficult problem with this engine design was the creation of a mechanism for transmitting the movement of the rack to the shaft. For this purpose, a special transfer device with balls and crackers was invented. When the piston with the rack flew up, the crackers, covering the shaft with their inclined surfaces, interacted with the balls in such a way that they did not interfere with the movement of the rack, but as soon as the rack began to move down, the balls rolled down the inclined surface of the crackers and tightly pressed them to the shaft, forcing it rotate. This design ensured the viability of the engine. Since Otto engines were almost five times more efficient than Lenoir engines, they were immediately in high demand. In subsequent years, about five thousand of them were produced. Otto worked hard to improve their design. Soon, the gear rack was replaced by a crank gear (many were embarrassed by the appearance of the rack, which flew up for a fraction of a second, besides, its movement was accompanied by an unpleasant rattling roar). But the most significant of his inventions came in 1877, when Otto took out a patent for a new four-stroke engine. This cycle still underlies the operation of most gas and gasoline engines to this day. The following year, the new engines were already put into production.
In all earlier gas engines, the mixture of gas and air was ignited in the working cylinder at atmospheric pressure. However, the effect of the explosion was the stronger, the greater the pressure. Therefore, when the mixture is compressed, the explosion should have been stronger. In Otto's new gas engine, the gas was compressed to 2, 5 or 3 atm, as a result of which the engine became smaller in size, and its power increased. To accommodate the gas mixture, the cylinder on one of its sides was lengthened. When the piston reached its final position here, there was still some space filled with a compressed gas mixture. Thanks to this, it became possible to produce an explosion at the final position of the piston, when it has zero speed when changing motion. With this dead center ignition system, it was possible to avoid shocks, shocks and tremors of the piston against the cylinder walls, which were in the previous engine. The piston stroke was as follows. 1) On the first piston stroke, a lean mixture of 1/10 gas and 9/10 air was sucked in through the open inlet valve and mixture inlet valve. 2) During the reverse stroke of the piston, the inlet was closed and the suction mixture was compressed in the cylinder. 3) At the end of this stroke, ignition occurred in the dead center and the developing pressure of the gaseous products of the explosion moved the piston. At the beginning of the third stroke, the pressure reached 11 atm, and during expansion it dropped to almost 3 atm. four). During the secondary reverse stroke of the piston, the exhaust valve opened, and the piston displaced combustion products from the cylinder. When it reached the extreme point, some residues of combustion products still remained in the cylinder, but they did not interfere with the further operation of the engine. On the contrary, their presence had a beneficial effect - instead of an explosion, more even combustion occurred, which is why the piston stroke turned out to be more even, without jerks, and the engine could be used where it had previously seemed unacceptable - for example, for the movement of looms and dynamos. This was an important advantage of the Otto engine. In order to make the rotation of the shaft even more uniform, it was equipped with a massive flywheel. After all, of the four strokes of the piston, only one corresponded to useful work, and the flywheel had to provide energy for three subsequent strokes (or, what is the same, during 1 revolutions) so that the working machines could go without slowing down. The mixture was ignited, as before, with an open flame. Due to the crank connection with the shaft, it was not possible to obtain gas expansion to atmospheric, and therefore the engine efficiency was not much higher than that of previous models, but it turned out to be the highest for heat engines of that time. The four-stroke cycle was Otto's greatest technical achievement. But it soon turned out that a few years before his invention, exactly the same principle of engine operation was described by the French engineer Beau de Roche. A group of French industrialists challenged Otto's patent in court. The court considered their arguments persuasive. Otto's rights deriving from his patent were greatly reduced, including the annulment of his monopoly on the four-stroke cycle. Otto painfully experienced this failure, meanwhile, the affairs of his company were going quite well. 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 light gas was used as fuel greatly narrowed the scope of the first internal combustion engines. The number of lighting and gas plants was insignificant even in Europe, and in Russia there were only two of them - in Moscow and St. Petersburg. Therefore, the search for a new fuel for the internal combustion engine did not stop. Some inventors have tried to use liquid fuel vapor as gas. Back in 1872, the American Brighton tried to use kerosene in this capacity. However, kerosene did not evaporate well, and Brighton switched to a lighter petroleum product, gasoline. But in order for a liquid fuel engine to successfully compete with gas, it was necessary to create a special device (later it became known as a carburetor) to evaporate gasoline and obtain a combustible mixture of it with air. Brighton in the same 1872 came up with one of the first so-called "evaporative "carburetors, but he acted unsatisfactorily. A workable gasoline engine did not appear until ten years later. It was invented by the German engineer Gottlieb Daimler. For many years he worked for the Otto 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 (like Watt in a similar situation in his time) reacted coldly to Daimler's proposal. 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 at the same time powerful enough to move the crew. Daimler expected to increase 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 hot hollow tube open into the cylinder.
The first model of a gasoline engine was intended for an industrial stationary installation. Here P is the gasoline tank, from which, with the help of a shut-off valve p, so much gasoline was passed through the pipe to the device for evaporating it AB, so that A always remained about 2/3 full. B is the lamp that was filled first, even before gasoline entered A. From lamp B, through a tube with valve V, gasoline was supplied to the burner, which was in the shell L; it flowed in a thin stream from the narrow tip of the burner and, thanks to the high temperature of the burner, immediately evaporated. The flames burned around the platinum igniter and heated it up. In evaporator A, gasoline vapors were generated by sucking heated air through the gasoline. These vapors were mixed with air in the control valve H, and thus a combustible gas mixture was obtained. During the downward stroke of the piston, it sucked in this mixture, during the reverse stroke it compressed it in the space intended for compression. At a time when the piston was at top dead center, the distribution mechanism opened a hot platinum igniter, the charge exploded, and the combustion gases pressed on the piston. For the formation of gasoline vapors, the air, as noted above, had to be preheated. This was achieved by the fact that the air before entering the evaporator passed through the burner casing.
To start the engine, after filling with gasoline A and B, the burner valve V was first opened and the burner tubes were heated from the outside for one or two minutes. So they reached the temperature at which gasoline began to evaporate. When the igniter was red hot, valve V was opened and the engine was rotated manually using a special handle; after a few revolutions, the first explosion occurred in the working cylinder; then the engine started to move. The working cylinder, as with gas engines, was surrounded by a shell through which water flowed for cooling from a water pipe or from a small pump Q, which was driven by the engine itself. From the above description, it can be seen that the process of evaporation of liquid fuel in the first gasoline engines left much to be desired. Therefore, the invention of the carburetor made a real revolution in engine building. The Hungarian engineer Donat Banki is considered to be its creator (although independently of him and even somewhat earlier, the same carburetor design was developed by Daimler's friend and ally Maybach). Banki later gained great fame for his outstanding inventions in the field of hydraulic turbines. But, while still a young man, in 1893 he took out a patent for a carburetor with a jet (nozzle), which was the prototype of all modern carburetors.
Unlike his predecessors, Banki proposed not to evaporate gasoline, but to finely spray it into the air. This ensured its uniform distribution over the cylinder, and the evaporation itself took place already in the cylinder under the action of compression heat. To ensure atomization, gasoline was sucked in by an air stream through a metering jet, and the constancy 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 the tube, located perpendicular to the air flow. To maintain pressure, a small tank with a float was provided, which maintained the level at a given height, so that the amount of gasoline sucked in was proportional to the amount of incoming air. Thus, the carburetor consisted of two parts: float chamber 1 and mixing chamber 2. Fuel freely entered chamber 1 from the tank through pipe 3 and was kept at the same level by float 4, which rose along with the fuel level and during filling, using lever 5 , lowered the needle 6 and thus blocked access to the fuel. From chamber 1, fuel flowed freely into chamber 2 and stopped in jet 7 at the same level as chamber 1. Chamber 2 had an opening at the bottom that communicated with outside air, and at the top - with the engine intake valve. The amount of mixture delivered to the cylinder was regulated by turning the throttle (flap) 8. During the suction stroke of the piston, air rushed from below into the mixing chamber and sucked fuel from the jet, spraying and evaporating it. The first internal combustion engines were single-cylinder, and in order to increase the power of the engine, it was common to increase the volume of the cylinder. Then they began to achieve this by increasing the number of cylinders. At the end of the XNUMXth century, two-cylinder engines appeared, and from the beginning of the XNUMXth century, four-cylinder engines began to spread. The latter were arranged in such a way that in each of the cylinders the four-stroke cycle was moved by one piston stroke. Thanks to this, good uniformity of rotation of the crankshaft was achieved.
Unlike the previous shaft, the crankshaft consisted of separate crankshafts, which were connected to separate pistons with the help of connecting rods. On the one hand, the shaft received motion from the pistons and converted the reciprocating motion into rotational motion, and on the other hand, it controlled the movement of the pistons, which due to this moved back and forth at precisely set moments, that is, they simultaneously passed through one working cycle in all cylinders. All these cycles alternated at regular intervals. Author: Ryzhov K.V.
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