One of the main factors in the development of engine building is the transfer of most of the engine to alternative fuels, including the replacement of light fuel with heavy fuel.
Extraction and processing, as well as delivery to places of consumption and storage diesel fuel compared to high-quality light oils, it is easier and more cost-effective.
The diesel engine in operating conditions is much more economical than gasoline.
The disadvantages inherent in high-speed diesel engines are as follows: their production is much more difficult, the specific gravity is greater, the engines are slow, i.e. require more metal for the same power.
At diesel engine the compression ratio is in the range of 16-20 units compared to 9-10 for gasoline engines, which provides more high efficiency. In addition, the diesel has regulation working mixture mostly high quality, i.e. regardless of speed crankshaft and load, almost the same amount of air is supplied to the cylinders, and the amount of fuel used increases with load. But even when full power the mass of injected fuel is 1.5-1.7 times less than that of gasoline engine the same working volume. This means that the actual compression ratio, i.e. the pressure and temperature of the end of compression, does not depend on the load, and the working mixture is always very lean compared to a gasoline engine. These factors provide the diesel engine with high efficiency of combustion and subsequent expansion even at partial load conditions.
Under operating conditions, the stability of power indicators and fuel consumption depends primarily on the resistance of the air cleaner, which affects the filling of cylinders with air (including turbocharged engines), the fuel injection advance angle, the nozzle needle lift start pressure (injection start pressure), quality atomization of fuel by injectors, as well as the nature (law) of fuel supply fuel pump high pressure.
It should be noted that the stability of the adjustment parameters of the fuel supply system for diesel engines is higher than for gasoline engines. However, during operation, it is necessary to strictly control the quality of air and fuel purification, as well as exclude the possibility of engine overheating, which will immediately affect the operation of the injectors and the piston group.
Diesel engines are more durable than gasoline engines, due to the stronger and more rigid execution of the cylinder block, crankshaft, parts cylinder-piston group, cylinder heads and the use of diesel fuel, which, unlike gasoline, to a certain extent is also a lubricant.
The disadvantages of diesel engines include a large mass, lower liter power, increased noise due to high combustion pressure and difficult start-up at low ambient temperatures, especially for cars that have passed 100,000 km or more. Wear out during operation plunger pairs high-pressure fuel pump, the tightness of the injector needle is broken, which leads to low revs at start-up (70-90 rpm) to poor fuel atomization. At the same time, as a result of the wear of the cylinder-piston group at this speed, the breakthrough of compressed air into the crankcase noticeably increases, which means that the pressure and temperature do not reach the values necessary to ignite the atomized fuel.
Star-shaped (radial) engines make it possible to compensate for a number of disadvantages inherent in diesel engines. Radial engines are lightweight with high power, since there are several cylinders per crankshaft crank, and the crankcase is quite compact. A small number of moving parts, the ability to provide air cooling, increase the reliability and maintainability of radial engines.
In this work, an attempt was made to create an engine that would combine the best qualities of diesel and radial engines.
In the graduation project, the task was set to develop a diesel radial engine for a city bus, based on the task, a patent study was carried out.
The patent search was carried out using the funds of the Federal Service for Intellectual Property, Patents and trademarks, as well as according to some sources of foreign countries. A search was made on patent documents for the last eighty years (1930 - 2010).
5, 10, 12 or more cylinders. Allows you to reduce the linear dimensions of the motor compared to an in-line arrangement of cylinders.
VR-shaped
"VR" is an abbreviation of two German words for V-shaped and R-row, i.e. "v-shaped-row". The engine was developed by Volkswagen and is a symbiosis of a V-engine with an extremely low 15° camber angle and an in-line engine. . The pistons are located in the block in a checkerboard pattern. The combination of the advantages of both types of engines led to the fact that the VR6 engine became so compact that it made it possible to cover both rows of cylinders with one common head, unlike a conventional V-twin engine. The result is a VR6 engine that is substantially shorter in length than an inline 6 and narrower in width than a conventional V6 engine. Installed since 1991 (model 1992) on Volkswagen Passat, Golf, Corrado, Sharan cars. It has factory indexes "AAA" with a volume of 2.8 liters, with a capacity of 174 l / s and "ABV" with a volume of 2.9 liters and a capacity of 192 l / s.
boxer engine- piston internal combustion engine, in which the angle between the rows of cylinders is 180 degrees. In automobiles and motorcycles, a boxer engine is used to lower the center of gravity, instead of the traditional V-shaped, as opposed to the arrangement of the pistons allows them to mutually neutralize vibrations, so that the engine has a smoother performance.
The boxer engine was most widely used in the Volkswagen Kaefer (Beetle, in the English version) model produced during the years of production (from to 2003) in the amount of 21,529,464 units.
Porsche uses it in most of its sports and racing models series , GT1 , GT2 and GT3.
The boxer engine is also hallmark Subaru brand cars, which is installed in almost all Subaru models since 1963 . Most engines of this company have boxer arrangement, which provides very high strength and rigidity of the cylinder block, but at the same time makes the engine difficult to repair. Old EA series engines (EA71, EA82 (produced until about 1994)) are famous for their reliability. Newer EJ, EG, EZ series engines (EJ15, EJ18, EJ20, EJ22, EJ25, EZ30, EG33, EZ36) mounted on various models Subaru from 1989 to the present (since February 1989, Subaru Legacy cars have been equipped with boxer diesel engines, coupled with mechanical box gears).
It was also installed on the Romanian Oltcit Club cars (it is an exact copy of the Citroen Axel), from 1987 to 1993. In motorcycle manufacturing boxer engines found wide application in BMW models, as well as in Soviet heavy motorcycles "Ural" and "Dnepr".
U-engine
- symbol power plant, which is two in-line engines, the crankshafts of which are mechanically connected using a chain or gear.
Known use cases: sports cars- Bugatti Type 45, an experimental version of Matra Bagheera; some marine and aircraft engines.
A U-shaped engine with two cylinders in each block is sometimes referred to as square four.
Counter-piston engine- the configuration of an internal combustion engine with the arrangement of cylinders in two rows one opposite the other (usually one above the other) in such a way that the pistons of the opposite cylinders move towards each other and have a common combustion chamber. The crankshafts are mechanically connected, power is taken from one of them, or from both (for example, when driving two propellers). The engines in this scheme are mostly turbocharged two-strokes. This scheme is used on aircraft engines, tank engines(T-64, T-80UD, T-84, Chieftain), locomotive engines (TE3, 2TE10) and large marine marine diesel engines. There is another name for this type of engine - an engine with oppositely moving pistons (an engine with a PDP).
Operating principle:
1 inlet
2 drive supercharger
3 air duct
4 safety valve
5 graduation KShM
6 inlet KShM (later by ~ 20 ° relative to the outlet)
7 cylinder with intake and exhaust ports
Issue 8
9 water cooling jacket
10 spark plug
Rotary engine- an air-cooled radial engine based on the rotation of cylinders (usually presented in an odd number) along with a crankcase and a propeller around a fixed crankshaft mounted on a motor frame. Similar engines were widely used during the First World War and the Russian Civil War. During these wars, these engines were superior in specific gravity to water-cooled engines, so they were mainly used (in fighters and reconnaissance aircraft).
star engine (radial engine) - piston engine internal combustion, the cylinders of which are located in radial rays around one crankshaft through equal angles. The star-shaped motor is short and allows for compact placement a large number of cylinders. Has found wide application in aviation.
star engine differs from other types in the design of the crank mechanism. One connecting rod is the main one, it looks like a connecting rod conventional engine with an in-line arrangement of cylinders, the rest are auxiliary and are attached to the main connecting rod along its periphery (the same principle is used in V-shaped engines). A disadvantage of the design of the star-shaped engine is the possibility of oil flowing into the lower cylinders during parking, and therefore it is necessary to make sure that there is no oil in the lower cylinders before starting the engine. Starting the engine in the presence of oil in the lower cylinders leads to water hammer and breakage of the crank mechanism.
Four-stroke radial motors have odd number cylinders in a row - this allows you to give a spark in the cylinders "through one".
Rotary piston engine internal combustion engine (RPD, Wankel engine), the design of which was developed in the year by NSU engineer Walter Freude, he also owned the idea of \u200b\u200bthis design. The engine was co-developed with Felix Wankel, who was working on a different rotary piston engine design.
A feature of the engine is the use of a trihedral rotor (piston), which has the form of a Reuleaux triangle, rotating inside a cylinder of a special profile, the surface of which is made according to an epitrochoid.
Design
The rotor mounted on the shaft is rigidly connected to the gear wheel, which engages with the fixed gear - the stator. The diameter of the rotor is much larger than the diameter of the stator, despite this, the rotor with the gear wheel rolls around the gear. Each of the vertices of the trihedral rotor moves along the epitrochoidal surface of the cylinder and cuts off the variable volumes of the chambers in the cylinder with three valves.
This design allows any 4-stroke Diesel, Stirling or Otto cycle to be carried out without the use of a special gas distribution mechanism. Sealing of the chambers is provided by radial and end sealing plates pressed against the cylinder centrifugal forces, gas pressure and band springs. The absence of a gas distribution mechanism makes the engine much simpler than a four-stroke piston engine (the saving is about a thousand parts), and the absence of interface (crankcase space, crankshaft and connecting rods) between individual working chambers ensures extraordinary compactness and high power density. In one revolution, the vankel performs three complete work cycles, which is equivalent to the operation of a six-cylinder piston engine. The mixture formation, ignition, lubrication, cooling, start-up are fundamentally the same as those of a conventional piston internal combustion engine.
Practical application was received by engines with trihedral rotors, with the ratio of gear and gear radii: R: r = 2: 3, which are installed on cars, boats, etc.
Engine configuration W
The engine was developed by Audi and Volkswagen and consists of two V-shaped engines. Torque is taken from both crankshafts.
Rotary vane engine internal combustion engine (RLD, Vigriyanov engine), the design of which was developed in 1973 by engineer Mikhail Stepanovich Vigriyanov. The peculiarity of the engine is the use of a rotating compound rotor placed inside the cylinder and consisting of four blades.
Design On a pair of coaxial shafts, two blades are installed, dividing the cylinder into four working chambers. Each chamber performs four working cycles in one revolution (a set of working mixture, compression, working stroke and exhaust gas emission). Thus, within the framework of this design, it is possible to implement any four-stroke cycle. (Nothing prevents you from using this design to work steam engine, only the blades will have to use two instead of four.)
Engine Balance
Degree of balance |
|||||||||||||||||||||
1 | R2 | R2* | V2 | B2 | R3 | R4 | V4 | B4 | R5 | VR5 | R6 | V6 | VR6 | B6 | R8 | V8 | B8 | V10 | V12 | B12 |
|
Forces of inertia of the first | |||||||||||||||||||||
Operation of a radial piston engine.
Hello friends!
Today we are starting a series of articles on specific types of aircraft engines. The first engine that will receive our attention is . He has every right to be the first, because he is the same age modern aviation. One of the first planes to take to the air was the Wright Brothers Flyer 1 (I think you've read about it :-)). And on it was a proprietary piston engine that ran on gasoline.
For a long time, this type of engine remained the only one, and only in the 40s of the 20th century did the introduction of an engine of a completely different principle of operation begin. It was a turbojet engine. Why did this happen, read on. However, the piston engine, although it lost its position, did not leave the stage, and now, due to the rather intensive development of the so-called small aviation (or aviation general purpose) he just got a second birth. What does it represent aircraft piston engine?
The operation of an internal combustion engine (the same in-line piston engine).
As always :-) ... In principle, nothing complicated (TRD is much more complicated :-)). In fact, this is a conventional internal combustion engine (ICE), the same as on our cars with you. Who has forgotten what an internal combustion engine is, let me remind you in a nutshell. This, simply put, is a hollow cylinder into which a solid cylinder is inserted, smaller in height (this is the piston). Into the space above the piston right moment a mixture of fuel (usually gasoline) and air is supplied. This mixture is ignited by a spark (from a special electric candle) and burns out. I will add that ignition can occur without a spark, as a result of compression. This is how the well-known diesel engine. Combustion results in gases of high pressure and temperature, which press on the piston and make it move. This very movement is the essence of the whole question. Then it is transmitted through special mechanisms to the place we need. If it's a car, then on its wheels, and if it's an airplane, then on its air propeller. There can be several such cylinders, more precisely, even many :-). From 4 to 24. This number of cylinders provides sufficient power and stability of the engine.
Another scheme for the operation of one row of cylinders.
Of course, an aircraft piston engine is only fundamentally similar to a conventional internal combustion engine. In fact, aviation specifics are necessarily present here. made of more advanced and high-quality materials, more reliable. With the same mass, it is much more powerful than a car. Usually it can work in an inverted position, because for an aircraft (especially a fighter or sports) aerobatics is a common thing, but a car, of course, does not need this.
M-17 engine, piston, in-line, V-shaped. Installed on TB-3 aircraft (late 30s of the 20th century)
M-17 engine on the TB-3 wing.
Piston engines can differ both in the number of cylinders and in their arrangement. There are in-line engines (cylinders in a row) and radial (star-shaped). In-line engines can be single-row, double-row, V-shaped, etc. In star-shaped cylinders are arranged in a circle (in the form of a star) and there are usually five to nine of them (in a row). These engines, by the way, can also be multi-row, when the cylinders are in blocks one after another. Inline engines usually have liquid cooling(as in a car :-), they look more like automobiles in appearance), and radial ones are airy. They are blown by the oncoming air flow and the cylinders, as a rule, have ribs for better heat removal.
ASh-82 engine, radial, two-row. Installed on LA-5, PE-2 aircraft.
Aircraft LA-5 with ASh-82 engine.
Aircraft piston engines often have such a feature as altitude. That is, with an increase in altitude, when the density and air pressure fall, they can work without loss of power. supply fuel-air mixture can be done in two ways. Here is a complete analogy with a car. Either the mixture is prepared in special unit, called a carburetor and then fed into the cylinders ( carbureted engines), or fuel is directly injected into each cylinder in accordance with the amount of air entering the same cylinder. On cars of this type, engines are often called "injected".
Modern piston radial engine ROTEC R2800.
More powerful R3600 (more cylinders).
Unlike the usual automotive internal combustion engine, an aircraft piston engine does not need bulky (and, of course, heavy :-)) transmission mechanisms from pistons to wheels. All these axles, bridges, gears. For an airplane, weight is very important. Here, the movement from the piston is immediately transmitted through the connecting rod to the main crankshaft, and it already has the second important part of an aircraft with a piston engine - a propeller. A screw is, so to speak, an independent (and very important) unit. In our case, he is the "motor" of the aircraft, and from his correct operation depends on the quality of the flight. The screw is not part of the engine, but they work in close cooperation :-). The screw is always selected or designed and calculated for a specific engine, or they are created simultaneously, so to speak, as a set :-).
Radial engine M-14P. Mounted on sports SU-26, Yak-55.
SU-26 with M-14P engine.
The principle of operation of the screw is a rather serious (and no less interesting :-)) question, so I decided to highlight it in , but for now let's get back to the hardware.
I already said that now piston aircraft engine again "gaining momentum". True, the composition of aviation using these engines is now different. Accordingly, the composition of the engines used has also changed. Heavy and bulky in-line engines are practically a thing of the past. A modern piston engine (most often) is a radial engine with 7-9 cylinders, with good fuel automatics with electronic control. One of the typical representatives of this class, for example, the ROTEC 2800 engine for light aircraft, was created and produced in Australia (by the way, immigrants from Russia :-)). However, about inline engines don't forget either. Such, for example, is ROTAX-912. The engine is also well known. domestic production M-14P, which is installed on the Yak-55 and SU-26.
Engine Rotax-912, in-line. Installed on Sports-Star Max light sport aircraft
Sports aircraft Sport-Star Max c engine Rotax-912.
There is a practice of using diesel engines (as a kind of piston) in aviation, since the war. However, this engine is not yet widely used due to existing problems in development, in particular in the field of reliability. But work is still underway, especially in light of the upcoming shortage of petroleum products.
In general, it's too early to write off :-). After all, as you know, the new is the well-forgotten old... Time will tell...
The main difference between a star engine and other types of piston engines lies in the design of the crank mechanism. One connecting rod is the main connecting rod (it looks like a connecting rod of a conventional in-line engine), the rest are trailer and are attached to the main connecting rod along its periphery (the same principle is used in V-engines). A disadvantage of the design of the star-shaped engine is the possibility of oil flowing into the lower cylinders during parking, and therefore it is necessary to make sure that there is no oil in the lower cylinders before starting the engine. Starting the engine in the presence of oil in the lower cylinders leads to water hammer and breakage of the crank mechanism.
Depending on the size and power of the engine, radial engines can form several stars-compartments due to the lengthening of the crankshaft.
Four-stroke radial engines usually have an odd number of cylinders in the compartment - this allows you to give a spark in the cylinders "through one". It is also possible to work with an even number of cylinders (most often when the cylinders are arranged in several rows), but to ensure smooth running, their number cannot be a power of 2.
Write a review on the article "Star engine"
Notes
Links
- // //autokadabra.ru - DIY, May 1, 2012
|
||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
An excerpt characterizing the star engine
- That's power! one said. - And the roof and ceiling were so smashed to pieces.“It blew up the earth like a pig,” said another. - That's so important, that's so cheered up! he said laughing. - Thank you, jumped back, otherwise she would have smeared you.
The people turned to these people. They paused and told how, near by, their cores had got into the house. Meanwhile, other shells, sometimes with a quick, gloomy whistle - cannonballs, then with a pleasant whistle - grenades, did not stop flying over the heads of the people; but not a single shell fell close, everything endured. Alpatych got into the wagon. The owner was at the gate.
- What did not see! he shouted at the cook, who, with her sleeves rolled up, in a red skirt, swaying with her bare elbows, went to the corner to listen to what was being said.
“What a miracle,” she said, but, hearing the voice of the owner, she returned, tugging at her tucked-up skirt.
Again, but very close this time, something whistled like a bird flying from top to bottom, a fire flashed in the middle of the street, something shot and covered the street with smoke.
"Villain, why are you doing this?" shouted the host, running up to the cook.
At the same moment with different sides the women wailed plaintively, the child wept in fright, and silently crowded the people with pale faces around the cook. From this crowd, the groans and sentences of the cook were heard most audibly:
- Oh, oh, my darlings! My doves are white! Don't let die! My doves are white! ..
Five minutes later there was no one left on the street. The cook, with her thigh shattered by a grenade fragment, was carried into the kitchen. Alpatych, his coachman, Ferapontov's wife with children, the janitor were sitting in the basement, listening. The rumble of guns, the whistle of shells, and the pitiful groan of the cook, which prevailed over all sounds, did not stop for a moment. The hostess now rocked and persuaded the child, then in a pitiful whisper asked everyone who entered the basement where her master was, who remained on the street. The shopkeeper, who entered the basement, told her that the owner had gone with the people to the cathedral, where they were raising the miraculous Smolensk icon.
By dusk, the cannonade began to subside. Alpatych came out of the basement and stopped at the door. Before a clear evening, the sky was all covered with smoke. And through this smoke a young, high-standing sickle of the moon shone strangely. After the former terrible rumble of guns had fallen silent over the city, silence seemed to be interrupted only by the rustle of steps, groans, distant screams and the crackle of fires, as it were spread throughout the city. The groans of the cook are now quiet. From both sides, black clouds of smoke from fires rose and dispersed. On the street, not in rows, but like ants from a ruined tussock, in different uniforms and in different directions, soldiers passed and ran through. In the eyes of Alpatych, several of them ran into Ferapontov's yard. Alpatych went to the gate. Some regiment, crowding and hurrying, blocked the street, going back.
piston engine air-cooled M-62 was developed in the design bureau of A.D. Shvetsov in 1933. Was taken as a basis american engine Wright "Cyclone" R-1820 F3. The design uses a number original solutions: double-damper crankshaft, elastic timing gear, side seal of the main connecting rod, flanking of the tooth of the fixed gear of the reducer (on ASh-62IR). Mass production organized in 1937 at the plant number 19 in Perm, later - at the Voronezh Mechanical Plant. M-62 (ASH-62) is a piston, 9-cylinder, single-row, star-shaped engine. Air cooling. Carburetor type AKM-62IRA is equipped with automatic adjustment of high-altitude gas. The engine is started from the RIM-U-24IR electric starter or manually by spinning the starter flywheel. The motor shaft rotates clockwise when viewed from the back of the crankcase. B-70 (B-91) aviation gasoline is used as fuel. Fuel is supplied by a BNK-12BK type fuel pump. Ignition is carried out from a BSM-9 magneto. Used for lubrication engine oil grades MK-22, MS-20. The ASh-62IR engine is equipped with planetary gear with a reduction ratio of 11:16. The ASh-62IR engine became the most massive modification of the M-62: more than 3,500 engines were built in total. Beginning in 1942, the ASh-62IR became the only modification of the M-62 that was in production by that time. The engine had 12 series and reached a resource of 600 hours. Modification ASh-62IR was produced under license in China (HS5) - at least 2600 copies. and in Poland (ASz-62) - 25106 copies. It is still operated on the An-2 aircraft. The motor was mass-produced in the USSR and Russia for more than 50 years. Engine modifications: M-62 (ASH-62) - basic. It was used on the aircraft I-153, I-16 (types 18 and 27), I-207, KOR-2 (Be-4), R-10 (KhAI-5), KhAI-52. ASh-62IR - geared. Designed in 1938. It was used on An-2, Li-2, GTS, PS-35, BSh-1. ASh-62M - modified. Used on An-2M. M-62R - high-rise. Notable for 2 turbochargers TK-19. HS-5 - Chinese version of ASh-62IR. Produced at the aircraft repair plant in Suzhou. Manufactured at least 2600 engines. ASz-62 - Polish variant, 25106 engines produced. Specifications: Length, mm: 1328 Diameter, mm: 1380 Number of cylinders: 9 Cylinder displacement, l: 29.87 Compression ratio: 6.4 Dry weight, kg: 560 Takeoff power, hp: 1000 Ground power, hp: 820 Power at 1500 m, hp: 840 Specific consumption fuel, g / (hp hour), - operational: 260-290 - ground rated: 280-300 - high-altitude rated: 280-300 - take-off power: at least 300 Speed, rpm: 2200 Oil consumption: 4% of fuel consumption Turbocharging: vane supercharger Pros and cons of a radial piston engine. The only drawback of such engines is the possibility of oil getting into the lower engine cylinders when the aircraft is parked. This can lead to instant water hammer and, accordingly, to breakage of the entire crank mechanism. To avoid such a srach, before starting the engine, it is constantly necessary to check the lower cylinders for the absence of oil in them. Of the pros radial engine it is worth noting its relatively small size, ease of operation and decent power (often installed on sports aircraft).
The device and principle of operation of a radial engine - video
READ ALSO ON THE SITEThe ZMZ 4062.10 engine was produced in several versions and trim levels. The power unit has high specifications, but at the same time quite easy to repair and maintain. Most frequent problems the thermostat is failing... The VAZ 11183 engine is a modernization product of the well-known 2111 engine. Like all previous models, the VAZ 11183 engine is a classic four-stroke, in-line, 4-cylinder power unit overhead distributor... All modifications of the diesel engine "D-245" Minsky engine plant- These are 4-stroke piston four-cylinder engines. The arrangement of cylinders in them is in-line, vertical, diesel fuel injection is direct, with compression ignition. Initial... A good friend of mine, a motorist and a former motorcycle racer who is very respected by me, once said a phrase about a two-stroke engine that I remember very much: "Life two-stroke motor like a butterfly, very bright, but short-lived. "I remembered this phrase after that ... |
