Gas and gasoline engines
The steam engine is not fully solved the energy problem facing humanity. Small shops and businesses, who formed in the XIX century, most of the industrial sector, is not always able to take advantage of it. The fact that a small steam engine had a very low efficiency (less than 10%). Furthermore, the use of such an engine has been associated with high cost and hassle. In order to run it on the course, it was necessary to build a fire and bring the pair. Even if the machine is needed only occasionally, it still had to keep under steam. For small-scale industry needed a little engine power, take up little space, which can be start and stop at any time without long preparation. The idea of such an engine was proposed at the beginning of the XIX century.
In the last year of the XVIII century French engineer Philippe Lebon opened coal gas. Tradition attributes its success chance - Lebon saw as gas flared, flowing out of the fire on the vessel supplied with sawdust, and realized what benefits can be derived from this phenomenon. In 1799 he received a patent for the use and method of producing coal gas by dry distillation of wood or coal. This discovery was of great importance especially for the development of lighting technology. Very soon, in France, and then in the rest of Europe gas lamps began to compete with the expensive candles. However, coal gas not only suited for illumination. In 1801, Le Bon took a patent for a gas engine design. The principle of operation of this machine is based on the known properties of open Gas: its mixture with the air exploded when ignited with the release of a large amount of heat. Combustion products is expanding rapidly, exerting strong pressure on the environment. By creating the appropriate conditions, the energy can be used stand-out for the benefit of man. two compressors and mixing chamber are provided in the engine Lebon. A compressor has been pumped into the compressed air chamber and the other - the compressed coal gas from the gasifier. Gas mixture is then acted in the working cylinder, which ignited. The engine was a dual action, ie, alternately acting working chambers located on both sides of the piston. Essentially, Lebon hatched the idea of an internal combustion engine, but he died in 1804 before he could realize his invention. But the idea of it, and later attracted the most attention. Indeed, the principle of action of the gas engine is much simpler than the steam engine, since the fuel is itself directly produces the pressure on the piston, while the steam engine thermal energy is first transferred to another medium - water vapor, which performs useful work.
In subsequent years, several inventors from different countries tried to create a workable engine on illuminating gas. However, all these attempts have not led to the appearance on the market of engines that could compete with the steam engine. The honor of creating commercially successful internal combustion engine belongs to the Belgian engineer Jean Etienne Lenoir. Working on the electroplating factory, Lenoir came to the conclusion that the fuel-air mixture in a gas engine can be ignited by an electric spark, and decided to build an engine based on this idea.
The owner of the galvanic shop stocked Lenoir money, to which he has built and in 1860 his first engine. And in appearance, and the device it resembled a steam engine. The engine was a dual action. Lower valve alternately supplied air and gas in the cylinder chamber located on the opposite sides of the piston. Upper valve serving for the discharge of exhaust gases. Gas and air supply to the spool on separate channels. Suction mixture into each cavity occurred approximately half way, and then overlaps the inlet port valve, and the mixture is ignited by an electric spark. Burning, it expands and acting on the piston, producing useful work. After the reaction, the second spool reported cylinder exhaust pipe. Meanwhile the ignition of the mixture occurred on the other side of the piston. He began to move backwards, forcing the exhaust gases.
Lenoir not immediately successful. Once able to produce all the parts and assemble the car, she worked quite a bit and stopped, as due to the heat and the piston expanded jammed in the cylinder. Lenoir has improved its engine, thoughtful water cooling system. However, the second launch attempt also ended in failure due to poor stroke. Lenoir has added its design lubrication system. Only then the engine began to work.
After the announcement of this invention, the workshop began to receive orders for the new engine, but his work continued to be unsatisfactory - the ignition system is often faltering, without lubrication valve is not working and it was not possible to establish its satisfactory lubrication at a temperature of 800 degrees. motor efficiency barely reached 4%, it consumes a huge amount of lubricant and gas. Nevertheless, the engine quickly became widespread. Its main buyers were small enterprises (printing, repair shops, etc..), For which steam engines were too expensive and cumbersome. Meanwhile Lenoir engine was simple to use, lightweight and has a small size. In 1864, more than 300 of these engines were produced in different capacities. Get Rich, Lenoir stops working on improving their car, and it has predetermined her fate - she was ousted from the market more perfect engine, created by German inventor Otto Augustus. In 1864 he received a patent for his model of the gas engine and later that year signed a contract with a rich engineer Langen for the operation of this invention. Soon the company "Otto and Company" was established.
At first glance, the Otto engine is a step backward compared with the engine Lenoir. The cylinder was vertical. A rotating shaft placed above the cylinder side. Along the axis of the piston has been attached thereto rack associated with the shaft. The engine works as follows. Rotary piston shaft raised to 1/10 the height of the cylinder, whereby was formed a piston space and unloaded occurred suction air and gas mixture. The mixture is then ignited. Neither Otto nor Langen not possessed sufficient knowledge in the field of electrical engineering and abandoned the electric ignition. Inflammation they carried out an open flame through the tube. With the explosion of the pressure under the piston is increased to about 4 atm. Under the influence of this pressure piston is raised, the volume of gas has increased and the pressure dropped. When lifting piston special mechanism disconnects the rail from the shaft. Piston first gas under pressure, and then raised by inertia until until it was produced under vacuum. Thus, unburned fuel energy is used in an engine with a maximum completeness. This was the main finding of the original Otto. The stroke of the piston down began under atmospheric pressure, and after the in-cylinder pressure reached atmospheric, open the drain valve and piston displacing its mass of exhaust gases. Because of the complete expansion of the combustion efficiency of the engine products was significantly higher than the efficiency of the Lenoir engine and reached 15%, which is superior to the best efficiency of the steam engines of the time.
The most difficult problem in this motor design was to create a rack drive transmission mechanism to the shaft. For this purpose, it was invented by a special transfer device with balls and crackers. When the piston with rack flew up, croutons, covering the shaft with their inclined surfaces, so interacted with balls that they do not impede the movement of the rack, but as soon as the rail began to move down the balls rolled down the inclined surface of crackers and tightly pressed them to the shaft, forcing him rotate. This design ensured the viability of the engine.
Since Otto engines were almost five times more economical engines Lenoir, they immediately began to enjoy great demand. In subsequent years, there are about five thousand units were produced. Otto worked hard on improving their design. Soon rack replaced the crank transmission (many confused view of the rack, go up for a second, besides its movement was accompanied by an unpleasant rattling roar). But the most significant of his inventions was done in 1877, when Otto took out a patent on a new engine with a four-stroke cycle. This is still a cycle forms the basis of most gas and petrol engines. The following year, the new engines have already been put into production.
In all earlier engines gas mixture ignited gas and air in the working cylinder at atmospheric pressure. However, the effect of the explosion was the stronger, the pressure was greater. Therefore, if the compression of a mixture of the explosion had to be stronger. The new gas engine Otto gas is compressed to 2, 3 or 5 atm, so that the engine is smaller in size, and its capacity increased. To place a cylinder of the gas mixture on one of its sides was lengthened. When the piston is reached to its end position, there were still some space filled with compressed gas mixture. This made it possible to produce an explosion at the end position of the piston when it is at a change rate of movement is zero. In this system, the ignition dead center managed to avoid bumps, jolts and shocks of the piston cylinder walls that have been in the same engine. The piston stroke was next. 1) At the first stroke of the piston through the open intake valve and the valve inlet mixture sucked poor gas mixture consisting of gas 1/10 and 9/10 air. 2) When the return stroke of the piston inlet was closed and sucked mixture is compressed in the cylinder. 3) At the end of the course took place in the dead center of the ignition and growing pressure of the gaseous products of the explosion moved the piston. At the beginning of the third stroke the pressure reached 11 atm, and the expansion was decreased nearly to 3 atm. 4) When the secondary piston return stroke the exhaust valve opens and the piston is forced out from the cylinder combustion products. When he reached the extreme point in the cylinder were still some remnants of the combustion products, but they do not interfere with the further operation of the engine. On the contrary, their presence had a positive impact - instead of an explosion happened more even burn, why and stroke to obtain more smooth, without jerks, and the engine can be used in areas where before it seemed inappropriate - for example, to move looms and dynamos. This is an important advantage of the Otto engine. To make the rotation of the shaft more evenly, it supplied a massive flywheel. After all of the four strokes of the piston is only one matched useful work, and the flywheel had to provide energy for the next three moves (or, equivalently, during 1, 5 rpm), to operate the machine could go without slowing down. Ignition of the mixture was carried out as before, open flame. Due to the connection of the crank shaft to receive an extension to the atmospheric gas failed, and therefore engine efficiency was only slightly higher than that of previous models, but it was the highest for the heat engines of the time.
Four-cycle was the biggest technical achievement Otto. But it was soon discovered that a few years before its invention, is the same engine operating principle was described by the French engineer Bo de Roche. French industrialists Group challenged in court the patent Otto. The Court considered their arguments convincing. Otto rights arising from its patent, have been significantly reduced, including its been canceled monopoly on the four-stroke cycle. Otto painfully experienced this setback, between the case of his company were not bad at all. Although the competitors began to produce four-stroke engines, Waste long production model Otto everything was still the best, and the demand for it has not stopped. By 1897, about 42 thousand of these engines were produced in different capacities. However, the fact that the fuel used coal gas, greatly narrowed the scope of the first internal combustion engines. Number svetilnogazovyh plants was negligible even in Europe, and in Russia they generally had only two - in Moscow and St. Petersburg.
So do not stop looking for a new fuel for the internal combustion engine. Some inventors tried to use as a pair of liquid fuel gas. In 1872 the American Brighton tried to use this as kerosene. However, kerosene bad evaporated, Brighton and moved on to more light oil products - gasoline. But in order for the engine liquid fuel could compete with gas, it was necessary to create a special device (later it became known as the carburetor) to vaporize the fuel and produce a combustible mixture thereof with Brighton air in the same 1872 came up with one of the first so-called "evaporative "carburetors, but he acted poorly.
Workable petrol engine only appeared ten years later. The inventor of it was a German engineer Gottlieb Daimler. For many years he worked in the company and Otto was a member of its board. In the early 80s, he suggested to his chief the project compact gasoline engine, which could be used in transport. Otto (as in his time Watt in a similar situation) reacted to the proposal of the Daimler cold. Then Daimler together with his friend Wilhelm Maybach made a bold decision - in 1882 they left the company Otto, purchased a small workshop near Stuttgart and began work on his project. Challenges facing Daimler and Maybach was not an easy task, they decided to create an engine that would not require the gas generator, would be very lightweight and compact, but powerful enough to move the carriage. The increase in power Daimler expected to receive by increasing the rotational speed, but it was to provide the desired frequency ignition of the mixture is necessary. In 1883, the first petrol engine with ignition by the glow of a hollow tube, open the cylinder was created.
The first model of the gasoline engine designed for industrial fixed installation. Here, P - petrol tank, which by means of the stop valve through the pipe p as gasoline was passed to the apparatus for its evaporation AB, that A always remains filled approximately 2/3. B - is the lamp that was filled first, before getting gasoline A. From B lamp through a tube with a valve V petrol supply to the burner is in the shell L; He emerged from a narrow trickle burner tip and thanks to the high temperature burner immediately evaporated. The flames burned around platinum igniter and it glows. The device for the evaporation of gasoline A pair formed with the sucking fuel through heated air. These vapors were mixed with air in the regulating valve H, and thus the combustible gas mixture was obtained. When the downstroke it sucks the mixture, during the back held her in space) intended for compression. At a time when the piston is at top dead center, a distribution mechanism opened incandescent platinum igniter charge exploded, and the combustion gas put pressure on the piston. For the formation of the air gasoline vapor, as noted above, it should be preheated. This is achieved in that the air before it enters the evaporator passes through the burner cover.
To start the engine, the gasoline filling by A and B, first open the burner valve V and within one or two minutes heated from the outside of the burner tube. Thus achieved a temperature at which gas begins to evaporate. When the igniter is red hot, open the valve V and the engine was rotated by hand with a special handle; after a few revolutions came the first explosion in the working cylinder; then the motor is in motion. Slave Cylinder, like gas engines surrounded the shell, through which the cooling water from the tap or from a small pump, Q, which was set in motion by the engine.
From the above description it is clear that the process of evaporation of the liquid fuel in the first petrol engines leave much to be desired. Therefore, a real revolution in engine produced the invention of the carburettor. Creator it is considered a Hungarian engineer Donut Banks (though independently of him, and even somewhat earlier the same carburetor design developed friend and colleague Daimler Maybach). Later, the bank acquired great fame for its outstanding inventions in the field of hydraulic turbines. But, even as a young man, he in 1893 took out a patent on the carburetor with throttle (nozzle), which was the prototype of all modern carburetors. Unlike their predecessors, the bank offers not vaporize gasoline and finely disperse it into the air. This ensured uniform distribution on the cylinder itself and evaporation occurred in the cylinder under the action of heat of compression. To provide spray of gasoline occurred suction air stream through the metering orifice, and the constancy of the mixture is achieved by maintaining a constant level of gasoline in the carburetor. Nozzle carried by one or more holes in the tube was situated perpendicular to air flow. To maintain a small pressure tank with float, which supported at a predetermined height level has been provided so that the amount of intake of gasoline was proportional to the amount of inlet air.
Thus, the carburetor consisted of two parts: the float chamber 1 and the mixing chamber 2. The fuel cell 1 to flow freely from the tank and the tube 3 was kept at the same level float 4, which is raised together with the fuel filling level, and, via lever 5 , took his needle 6 and the closed access to fuel. From chamber 1 the fuel to flow freely into the chamber 2 and stopped in the nozzles 7 at the same level with the chamber 1. The chamber had two bottom opening communicating with the outside air, and above - with the suction valve of the engine. Number of delivered to the cylinder mixture was adjusted by turning the throttle (throttle) 8. When the suction stroke of the piston the air rushed from the bottom in the mixing chamber and is sucked from the jet fuel, atomizing and evaporating it.
The first internal combustion engines were single-cylinder, and in order to increase the engine power is usually increased the volume of the cylinder. Then it began to seek an increase in the number of cylinders. At the end of XIX century there were two-cylinder engines, and from the beginning of the XX century began to spread four-cylinder. Recent arranged so that in each four stroke cycle engine was moved one stroke of the piston. This achieves a good uniformity of the rotation of the crankshaft.
Unlike the former shaft, crankshaft consisted of individual knee-cranks which via connecting rods have been linked with separate pistons. On one side of the shaft took the movement of the piston and converts reciprocating motion into rotary and on the other - control the movement of the pistons, which are thereby moved back and forth in a well-defined moments, that is, at the same time in all the cylinders were one power stroke. All these cycles alternated at regular intervals.