It would not be an exaggeration to say that most self-propelled devices today are equipped with internal combustion engines of various designs, using various operating principles. In any case, if we talk about road transport. In this article, we will take a closer look at ICE. What it is, how this unit works, what are its pros and cons, you will learn by reading it.
The principle of operation of internal combustion engines
The main principle of operation of an internal combustion engine is based on the fact that fuel (solid, liquid or gaseous) burns in a specially allocated working volume inside the unit itself, converting thermal energy into mechanical energy.
The working mixture entering the cylinders of such an engine is compressed. After its ignition, with the help of special devices, an excess pressure of gases arises, forcing the pistons of the cylinders to return to their original position. This creates a constant working cycle that converts kinetic energy into torque with the help of special mechanisms.
To date, the ICE device can have three main types:
- often called easy;
- four-stroke power unit, allowing to achieve higher power and efficiency values;
- with enhanced power characteristics.
In addition, there are other modifications of the main circuits that improve certain properties of power plants of this type.
Benefits of internal combustion engines
Unlike power units that provide for the presence of external chambers, the internal combustion engine has significant advantages. The main ones are:
- much more compact dimensions;
- higher power ratings;
- optimal efficiency values.
It should be noted, speaking of an internal combustion engine, that this is a device that in the vast majority of cases allows the use of various types of fuel. It can be gasoline, diesel fuel, natural or kerosene, and even ordinary wood.
Such versatility has given this engine concept its well-deserved popularity, ubiquity and truly world leadership.
Brief historical excursion
It is generally accepted that the internal combustion engine has been counting its history since the creation by the Frenchman de Rivas in 1807 of a piston unit that used hydrogen in a gaseous state of aggregation as fuel. And although since then the ICE device has undergone significant changes and modifications, the main ideas of this invention continue to be used today.
The first four-stroke internal combustion engine saw the light in 1876 in Germany. In the mid-80s of the XIX century, a carburetor was developed in Russia, which made it possible to dose the supply of gasoline to the engine cylinders.
And at the very end of the century before last, the famous German engineer proposed the idea of igniting a combustible mixture under pressure, which significantly increased the power characteristics of internal combustion engines and the efficiency indicators of units of this type, which had previously left much to be desired. Since then, the development of internal combustion engines has been mainly along the path of improvement, modernization and the introduction of various improvements.
The main types and types of internal combustion engines
Nevertheless, more than 100 years of history of this type of units has made it possible to develop several main types of power plants with internal combustion of fuel. They differ from each other not only in the composition of the working mixture used, but also in design features.
Gasoline engines
As the name implies, the units of this group use various types of gasoline as fuel.
In turn, such power plants are usually divided into two large groups:
- Carburetor. In such devices, the fuel mixture is enriched with air masses in a special device (carburetor) before entering the cylinders. Then it is ignited with an electric spark. Among the most prominent representatives of this type are the VAZ models, the internal combustion engine of which for a very long time was exclusively of the carburetor type.
- Injection. This is a more complex system in which fuel is injected into the cylinders through a special manifold and injectors. It can occur both mechanically and through a special electronic device. Common Rail direct injection systems are considered the most productive. Installed on almost all modern cars.
Injected gasoline engines are considered to be more economical and provide higher efficiency. However, the cost of such units is much higher, and maintenance and operation are much more difficult.
Diesel engines
At the dawn of the existence of units of this type, one could often hear a joke about the internal combustion engine, that this is a device that eats gasoline like a horse, but moves much more slowly. With the invention of the diesel engine, this joke has partially lost its relevance. Mainly because diesel is able to run on much lower quality fuel. This means that it is much cheaper than gasoline.
The main fundamental difference between internal combustion is the absence of forced ignition of the fuel mixture. Diesel fuel is injected into the cylinders by special injectors, and individual drops of fuel are ignited due to the pressure force of the piston. Along with the advantages, the diesel engine has a number of disadvantages. Among them are the following:
- much less power compared to gasoline power plants;
- large dimensions and weight characteristics;
- difficulties with starting under extreme weather and climatic conditions;
- insufficient traction and a tendency to unjustified power losses, especially at relatively high speeds.
In addition, repairing a diesel-type internal combustion engine is usually much more complicated and costly than adjusting or restoring the performance of a gasoline unit.
gas engines
Despite the cheapness of natural gas used as fuel, the construction of gas-fired internal combustion engines is incommensurably more complicated, which leads to a significant increase in the cost of the unit as a whole, its installation and operation in particular.
On power plants of this type, liquefied or natural gas enters the cylinders through a system of special gearboxes, manifolds and nozzles. The ignition of the fuel mixture occurs in the same way as in carburetor gasoline installations - with the help of an electric spark emanating from a spark plug.
Combined types of internal combustion engines
Few people know about combined ICE systems. What is it and where is it applied?
This, of course, is not about modern hybrid cars that can run both on fuel and on an electric motor. Combined internal combustion engines are usually called such units that combine elements of various principles of fuel systems. The most prominent representative of the family of such engines are gas-diesel plants. In them, the fuel mixture enters the internal combustion engine block in almost the same way as in gas units. But the fuel is ignited not with the help of an electric discharge from a candle, but with an ignition portion of diesel fuel, as happens in a conventional diesel engine.
Maintenance and repair of internal combustion engines
Despite a fairly wide variety of modifications, all internal combustion engines have similar basic designs and diagrams. Nevertheless, in order to carry out high-quality maintenance and repair of internal combustion engines, it is necessary to thoroughly know its structure, understand the principles of operation and be able to identify problems. To do this, of course, it is necessary to carefully study the design of internal combustion engines of various types, to understand for yourself the purpose of certain parts, assemblies, mechanisms and systems. This is not easy, but very exciting! And most importantly, necessary.
Especially for inquisitive minds who want to independently comprehend all the mysteries and secrets of almost any vehicle, an approximate schematic diagram of an internal combustion engine is presented in the photo above.
So, we found out what this power unit is.
Let's say your son asks you: "Dad, what is the most amazing motor in the world"? What will you answer him? A 1000-horsepower unit from the Bugatti Veyron? Or the new AMG turbo engine? Or a twin-supercharged Volkswagen engine?
There have been a lot of cool inventions lately, and all those supercharged injections seem amazing...if you don't know. For the most amazing motor that I know of was made in the Soviet Union and, you guessed it, not for the Lada, but for the T-64 tank. It was called 5TDF, and here are some amazing facts.
It was a five-cylinder, which in itself is unusual. It had 10 pistons, ten connecting rods and two crankshafts. The pistons moved in the cylinders in opposite directions: first towards each other, then back, again towards each other, and so on. Power take-off was carried out from both crankshafts to make it convenient for the tank.
The engine worked on a two-stroke cycle, and the pistons played the role of spools that opened the intake and exhaust windows: that is, it did not have any valves or camshafts. The design was ingenious and efficient - a two-stroke cycle provided maximum liter power, and direct-flow scavenging - high-quality cylinder filling.
In addition, the 5TDF was a direct injection diesel engine, where fuel was supplied to the space between the pistons shortly before the moment when they reached maximum convergence. Moreover, the injection was carried out by four nozzles along a tricky trajectory to ensure instant mixture formation.
But even this is not enough. The engine had a turbocharger with a twist - a huge turbine and compressor were placed on the shaft and had a mechanical connection with one of the crankshafts. Brilliant - in the acceleration mode, the compressor was twisted from the crankshaft, which excluded the turbo lag, and when the exhaust gas flow properly spun the turbine, the power from it was transferred to the crankshaft, increasing the efficiency of the motor (such a turbine is called a power turbine).
In addition, the engine was multi-fuel, that is, it could run on diesel fuel, kerosene, aviation fuel, gasoline, or any mixture of them.
Plus, fifty more unusual features, such as composite pistons with heat-resistant steel inserts and a dry sump lubrication system, like in racing cars.
All tricks pursued two goals: to make the motor as compact, economical and powerful as possible. All three parameters are important for a tank: the first facilitates layout, the second improves autonomy, and the third improves maneuverability.
And the result was impressive: with a working volume of 13.6 liters in the most forced version, the engine developed more than 1000 hp. For a diesel engine of the 60s, this was an excellent result. In terms of specific liter and overall power, the engine was several times superior to analogues of other armies. I saw it live, and the layout is really amazing - the nickname "Suitcase" suits him very well. I would even say "a tightly packed suitcase."
It did not take root due to excessive complexity and high cost. Against the background of 5TDF, any car engine - even from the Bugatti Veyron - seems somehow utterly banal. And what the hell is not joking, the technology can make a revolution and again return to the solutions once used on the 5TDF: a two-stroke diesel cycle, power turbines, multi-injector injection.
A massive return to turbo engines has begun, which at one time were considered too complicated for non-sports cars ...
In the engine device, the piston is a key element of the working process. The piston is made in the form of a metal hollow glass, located with a spherical bottom (piston head) up. The piston guide part, otherwise known as the skirt, has shallow grooves designed to hold the piston rings in them. The purpose of the piston rings is to ensure, firstly, the tightness of the above-piston space, where, during engine operation, the gasoline-air mixture is instantly burned and the resulting expanding gas could not, having rounded the skirt, rush under the piston. Secondly, the rings prevent the oil under the piston from entering the over-piston space. Thus, the rings in the piston act as seals. The lower (lower) piston ring is called the oil scraper ring, and the upper (upper) ring is called compression, that is, it provides a high degree of compression of the mixture.
When a fuel-air or fuel mixture enters the cylinder from a carburetor or injector, it is compressed by the piston as it moves up and ignited by an electric discharge from the spark plug (in a diesel engine, the mixture self-ignites due to sudden compression). The resulting combustion gases have a much larger volume than the original fuel mixture, and, expanding, sharply push the piston down. Thus, the thermal energy of the fuel is converted into a reciprocating (up and down) movement of the piston in the cylinder.
Next, you need to convert this movement into rotation of the shaft. This happens as follows: inside the piston skirt there is a finger on which the upper part of the connecting rod is fixed, the latter is pivotally fixed on the crankshaft crank. The crankshaft rotates freely on support bearings that are located in the crankcase of an internal combustion engine. When the piston moves, the connecting rod begins to rotate the crankshaft, from which the torque is transmitted to the transmission and - further through the gear system - to the drive wheels.
Engine specifications. Engine specifications When moving up and down, the piston has two positions, which are called dead points. Top dead center (TDC) is the moment of maximum lifting of the head and the entire piston up, after which it begins to move down; bottom dead center (BDC) - the lowest position of the piston, after which the direction vector changes and the piston rushes up. The distance between TDC and BDC is called the piston stroke, the volume of the upper part of the cylinder with the piston at TDC forms the combustion chamber, and the maximum cylinder volume with the piston at BDC is called the total volume of the cylinder. The difference between the total volume and the volume of the combustion chamber is called the working volume of the cylinder.
The total working volume of all cylinders of an internal combustion engine is indicated in the technical characteristics of the engine, expressed in liters, therefore, in everyday life it is called the engine displacement. The second most important characteristic of any internal combustion engine is the compression ratio (SS), defined as the quotient of dividing the total volume by the volume of the combustion chamber. For carburetor engines, SS varies from 6 to 14, for diesel engines - from 16 to 30. It is this indicator, along with engine size, that determines its power, efficiency and completeness of combustion of the fuel-air mixture, which affects the toxicity of emissions during engine operation. .
Engine power has a binary designation - in horsepower (hp) and in kilowatts (kW). To convert units to one another, a coefficient of 0.735 is applied, that is, 1 hp. = 0.735 kW.
The duty cycle of a four-stroke internal combustion engine is determined by two revolutions of the crankshaft - half a turn per stroke, corresponding to one stroke of the piston. If the engine is single-cylinder, then unevenness is observed in its operation: a sharp acceleration of the piston stroke during the explosive combustion of the mixture and slowing it down as it approaches BDC and further. In order to stop this unevenness, a massive flywheel disk with a large inertia is installed on the shaft outside the motor housing, due to which the moment of rotation of the shaft in time becomes more stable.
The principle of operation of the internal combustion engine
A modern car, most of all, is driven by an internal combustion engine. There are many such engines. They differ in volume, number of cylinders, power, rotation speed, fuel used (diesel, gasoline and gas internal combustion engines). But, in principle, the device of the internal combustion engine, it seems.
How does an engine work and why is it called a four-stroke internal combustion engine? I understand about internal combustion. Fuel burns inside the engine. And why 4 cycles of the engine, what is it? Indeed, there are two-stroke engines. But on cars they are used extremely rarely.
A four-stroke engine is called because its work can be divided into four parts equal in time. The piston will pass through the cylinder four times - twice up and twice down. The stroke begins when the piston is at its lowest or highest point. For motorists-mechanics, this is called top dead center (TDC) and bottom dead center (BDC).
First stroke - intake stroke
The first stroke, also known as intake, starts at TDC (top dead center). Moving down, the piston sucks the air-fuel mixture into the cylinder. The operation of this stroke occurs with the intake valve open. By the way, there are many engines with multiple intake valves. Their number, size, time spent in the open state can significantly affect engine power. There are engines in which, depending on the pressure on the gas pedal, there is a forced increase in the time the intake valves are open. This is done to increase the amount of fuel taken in, which, once ignited, increases engine power. The car, in this case, can accelerate much faster.
The second stroke is the compression stroke
The next stroke of the engine is the compression stroke. After the piston reaches its lowest point, it begins to rise, thereby compressing the mixture that entered the cylinder on the intake stroke. The fuel mixture is compressed to the volume of the combustion chamber. What kind of camera is this? The free space between the top of the piston and the top of the cylinder when the piston is at top dead center is called the combustion chamber. The valves are completely closed during this stroke of the engine. The tighter they are closed, the better the compression is. Of great importance, in this case, the condition of the piston, cylinder, piston rings. If there are large gaps, then good compression will not work, and, accordingly, the power of such an engine will be much lower. Compression can be checked with a special device. By the magnitude of the compression, one can draw a conclusion about the degree of engine wear.
Third cycle - working stroke
The third cycle is a working one, it starts from TDC. It is called a worker for a reason. After all, it is in this cycle that an action occurs that makes the car move. At this point, the ignition system comes into play. Why is this system so called? Yes, because it is responsible for igniting the fuel mixture compressed in the cylinder in the combustion chamber. It works very simply - the candle of the system gives a spark. In fairness, it is worth noting that the spark is issued on the spark plug a few degrees before the piston reaches the top point. These degrees, in a modern engine, are automatically regulated by the "brains" of the car.
After the fuel ignites, an explosion occurs - it sharply increases in volume, forcing the piston to move down. The valves in this stroke of the engine, as in the previous one, are in the closed state.
The fourth measure is the release measure
The fourth stroke of the engine, the last one is exhaust. Having reached the bottom point, after the working stroke, the exhaust valve begins to open in the engine. There may be several such valves, as well as intake valves. Moving up, the piston removes exhaust gases from the cylinder through this valve - it ventilates it. The degree of compression in the cylinders, the complete removal of exhaust gases and the required amount of intake air-fuel mixture depend on the precise operation of the valves.
After the fourth measure, it is the turn of the first. The process is repeated cyclically. And due to what does the rotation occur - the operation of the internal combustion engine all 4 strokes, which causes the piston to rise and fall in the compression, exhaust and intake strokes? The fact is that not all the energy received in the working cycle is directed to the movement of the car. Part of the energy is used to spin the flywheel. And he, under the influence of inertia, turns the crankshaft of the engine, moving the piston during the period of "non-working" cycles.
Gas distribution mechanism
The gas distribution mechanism (GRM) is designed for fuel injection and exhaust gases in internal combustion engines. The gas distribution mechanism itself is divided into a lower valve, when the camshaft is in the cylinder block, and an upper valve. The overhead valve mechanism implies that the camshaft is located in the cylinder head (cylinder head). There are also alternative gas distribution mechanisms, such as a sleeve timing system, a desmodromic system, and a variable phase mechanism.
For two-stroke engines, the gas distribution mechanism is carried out using intake and exhaust ports in the cylinder. For four-stroke engines, the most common overhead valve system, which will be discussed below.
Timing device
In the upper part of the cylinder block is the cylinder head (cylinder head) with the camshaft, valves, pushers or rocker arms located on it. The camshaft drive pulley is moved out of the cylinder head. To prevent the leakage of engine oil from under the valve cover, an oil seal is installed on the camshaft neck. The valve cover itself is mounted on an oil-petrol-resistant gasket. The timing belt or chain is worn on the camshaft pulley and is driven by the crankshaft gear. Tension rollers are used to tension the belt, tension “shoes” are used for the chain. Typically, the timing belt drives the water cooling pump, the intermediate shaft for the ignition system and the high pressure pump drive of the injection pump (for diesel versions).
On the opposite side of the camshaft, a vacuum booster, power steering or car alternator can be driven by direct transmission or by means of a belt.
The camshaft is an axle with cams machined on it. The cams are located along the shaft so that during rotation, in contact with the valve lifters, they are pressed exactly in accordance with the engine's operating cycles.
There are engines with two camshafts (DOHC) and a large number of valves. As in the first case, the pulleys are driven by a single timing belt and chain. Each camshaft closes one type of intake or exhaust valve.
The valve is pressed by a rocker (early versions of engines) or a pusher. There are two types of pushers. The first is pushers, where the gap is regulated by shims, the second is hydraulic pushers. The hydraulic pusher softens the blow to the valve due to the oil that is in it. Adjustment of the gap between the cam and the top of the pusher is not required.
The principle of operation of the timing
The entire gas distribution process is reduced to the synchronous rotation of the crankshaft and camshaft. As well as opening the intake and exhaust valves at a certain position of the pistons.
To accurately position the camshaft relative to the crankshaft, alignment marks are used. Before putting on the timing belt, the marks are combined and fixed. Then the belt is put on, the pulleys are “released”, after which the belt is tensioned by the tension rollers.
When the valve is opened with a rocker arm, the following happens: the camshaft "runs" on the rocker arm, which presses the valve, after passing through the cam, the valve closes under the action of the spring. The valves in this case are arranged in a v-shape.
If pushers are used in the engine, then the camshaft is located directly above the pushers, during rotation, pressing its cams on them. The advantage of such timing is low noise, low price, maintainability.
In a chain engine, the entire gas distribution process is the same, only when assembling the mechanism, the chain is put on the shaft together with the pulley.
crank mechanism
Crank mechanism (hereinafter abbreviated as KShM) is an engine mechanism. The main purpose of the crankshaft is to convert the reciprocating movements of a cylindrical piston into rotational movements of the crankshaft in an internal combustion engine and vice versa.
KShM device
Piston
The piston has the form of a cylinder made of aluminum alloys. The main function of this part is to convert the change in gas pressure into mechanical work, or vice versa - pressurization due to reciprocating motion.
The piston is a bottom, head and skirt folded together, which perform completely different functions. The piston head of a flat, concave or convex shape contains a combustion chamber. The head has cut grooves where the piston rings (compression and oil scraper) are placed. Compression rings prevent gas breakthrough into the engine crankcase, and piston oil scraper rings help remove excess oil on the inner walls of the cylinder. There are two bosses in the skirt, which provide the placement of the piston pin connecting the piston to the connecting rod.
A stamped or forged steel (rarely titanium) connecting rod has swivel joints. The main role of the connecting rod is to transfer the piston force to the crankshaft. The design of the connecting rod assumes the presence of an upper and lower head, as well as a rod with an I-section. The upper head and bosses contain a rotating ("floating") piston pin, while the lower head is collapsible, thus allowing for a close connection with the shaft journal. The modern technology of controlled splitting of the lower head makes it possible to ensure high precision of the connection of its parts.
The flywheel is mounted on the end of the crankshaft. Today, dual-mass flywheels are widely used, having the form of two elastically interconnected disks. The flywheel ring gear is directly involved in starting the engine through the starter.
Block and cylinder head
The cylinder block and cylinder head are cast iron (rarely aluminum alloys). The cylinder block has cooling jackets, beds for crankshaft and camshaft bearings, as well as attachment points for instruments and assemblies. The cylinder itself acts as a guide for the pistons. The cylinder head contains a combustion chamber, inlet-outlet channels, special threaded holes for spark plugs, bushings and pressed seats. The tightness of the connection of the cylinder block with the head is provided with a gasket. In addition, the cylinder head is closed with a stamped cover, and between them, as a rule, an oil-resistant rubber gasket is installed.
In general, the piston, cylinder liner and connecting rod form the cylinder or cylinder-piston group of the crank mechanism. Modern engines can have up to 16 or more cylinders.
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 banks of cylinders with one common head, unlike a conventional V-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 in the , GT1 , GT2 and GT3 series.
The boxer engine is also a hallmark of Subaru , which has been installed in almost all Subaru models since 1963 . Most of the engines of this company have an opposed layout, 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 engines of the EJ, EG, EZ series (EJ15, EJ18, EJ20, EJ22, EJ25, EZ30, EG33, EZ36) installed on various Subaru models from 1989 to the present (since February 1989, Subaru Legacy cars are equipped with boxer diesel engines coupled with a manual transmission).
It was also installed on the Romanian Oltcit Club cars (it is an exact copy of the Citroen Axel), from 1987 to 1993. In the production of motorcycles, boxer engines are widely used in BMW models, as well as in Soviet heavy motorcycles Ural and Dnepr.
U-engine- symbol of the power plant, which is two in-line engines, the crankshafts of which are mechanically connected by means of a chain or gear.
Notable use cases: sports cars - Bugatti Type 45, developmental variant of the 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), diesel 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 World War I 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) - a piston internal combustion engine, the cylinders of which are located in radial rays around one crankshaft through equal angles. The radial engine is short and allows a large number of cylinders to be placed compactly. 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 connecting rod, it is similar to the connecting rod of a conventional in-line engine, the rest are auxiliary 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.
Four-stroke radial engines have an odd number of 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 tops of the trihedral rotor moves along the epitrochoidal surface of the cylinder and cuts off the variable volumes of the chambers in the cylinder using 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. The sealing of the chambers is provided by radial and end sealing plates pressed against the cylinder by 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. (There is nothing to stop this design from being used to run a steam engine, only you have to use two blades instead of four.)
Engine Balance
Degree of balance |
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1 | R2 | R2* | V2 | B2 | R3 | R4 | V4 | B4 | R5 | VR5 | R6 | V6 | VR6 | B6 | R8 | V8 | B8 | V10 | V12 | B12 |
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Forces of inertia of the first | |||||||||||||||||||||
Counter-piston engine- the configuration of the internal combustion engine with the arrangement of pistons in two rows one opposite the other in common cylinders in such a way that the pistons of each cylinder move towards each other and form a common combustion chamber. The crankshafts are mechanically synchronized, and the exhaust shaft rotates ahead of the intake shaft by 15-22 °, power is taken either from one of them or from both (for example, when driving two propellers or two clutches). The layout automatically provides direct-flow scavenging - the most perfect for a two-stroke machine and the absence of a gas joint.
There is another name for this type of engine - counter-moving piston engine (engine with PDP).
The device of the engine with the oncoming movement of the pistons:
1 - inlet pipe; 2 - supercharger; 3 - air duct; 4 - safety valve; 5 - graduation KShM; 6 - inlet KShM (late by ~ 20° from the outlet); 7 - cylinder with inlet and outlet windows; 8 - release; 9 - water cooling jacket; 10 - spark plug. isometry
