Who invented the rotary engine. Rotary piston engine

With the invention of the engine internal combustion progress in the development of the automotive industry has stepped far ahead. Despite the fact that the general internal combustion engine device remained the same, these units were constantly improved. Along with these motors, more progressive rotary-type units appeared. Why haven't they been widely adopted? automotive world? We will consider the answer to this question in the article.

The history of the unit

The rotary engine was designed and tested by developers Felix Wankel and Walter Freude in 1957. The first car on which this unit was installed was the NSU Spyder sports car. Studies have shown that with an engine power of 57 Horse power this car had the ability to accelerate to a whopping 150 kilometers per hour. The production of the Spider car equipped with a 57-horsepower rotary engine lasted about 3 years.

After that, this type of engine began to equip the NSU Ro-80 car. Subsequently, rotary engines were installed on Citroens, Mercedes, VAZs and Chevrolets.

One of the most common rotary engine cars is the Japanese sports car Mazda Cosmo Sport. Also, the Japanese began to equip the RX model with this motor. The principle of operation of a rotary engine (Mazda RX) was to constantly rotate the rotor with a change in cycles of work. But more on that later.

At the present time, the Japanese automaker is not engaged in serial production of cars with rotary engines. The last model on which such a motor was installed was the Mazda RX8 of the Spirit R modification. However, in 2012, the production of this version of the car was discontinued.

Device and principle of operation

What is the principle of operation of a rotary engine? This type of motor is distinguished by a 4-stroke cycle of action, as in a classic internal combustion engine. However, the principle of operation of a rotary piston engine is slightly different from that of conventional piston engines.

What main feature this motor? rotary engine Stirling has in its design not 2, not 4 and not 8 pistons, but only one. It's called a rotor. This element rotates in a cylinder of a special shape. The rotor is mounted on the shaft and connected to the gear wheel. The latter has a gear clutch with a starter. The element rotates along an epitrochoidal curve. That is, the rotor blades alternately cover the cylinder chamber. In the latter, fuel combustion occurs. The principle of operation of a rotary engine (including Mazda Cosmo Sport) is that in one revolution the mechanism pushes three petals of hard circles. As the part rotates in the body, the three compartments inside change their size. Due to the change in dimensions, a certain pressure is created in the chambers.

Phases of work

How does a rotary engine work? The principle of operation (gif-images and the RPD diagram you can see below) of this motor is as follows. The operation of the engine consists of four repeating cycles, namely:

1. Fuel supply. This is the first phase of the engine. It occurs at the moment when the top of the rotor is at the level of the feed hole. When the chamber is open to the main compartment, its volume approaches a minimum. As soon as the rotor rotates past it, the fuel-air mixture enters the compartment. After that, the chamber becomes closed again.
2. Compressions. As the rotor continues its movement, the space in the compartment decreases. Thus, a mixture of air and fuel is compressed. As soon as the mechanism passes the spark plug compartment, the volume of the chamber decreases again. At this point, the mixture ignites.
3. Inflammations. Often, a rotary engine (including the VAZ-21018) has several spark plugs. This is due to the large length of the combustion chamber. As soon as the candle ignites the combustible mixture, the level of pressure inside increases tenfold. Thus, the rotor is driven again. Further, the pressure in the chamber and the amount of gases continue to grow. At this moment, the rotor moves and torque is created. This continues until the mechanism passes the exhaust compartment.
4. Release of gases. When the rotor passes this compartment, the gas under high pressure begins to move freely in exhaust pipe. In this case, the movement of the mechanism does not stop. The rotor rotates stably until the volume of the combustion chamber again drops to a minimum. By this time, the remaining amount of exhaust gases will be squeezed out of the engine.

This is exactly the principle of operation of a rotary engine. VAZ-2108, on which the RPD was also mounted, like the Japanese Mazda, was distinguished by the quiet operation of the engine and high dynamic characteristics. But in mass production this modification was never launched. So, we found out what the principle of operation of a rotary engine is.

Disadvantages and advantages

Not in vain this motor attracted the attention of so many automakers. Its special working principle and design have whole line advantages over other types of internal combustion engines.

So, what are the pros and cons of a rotary engine? Let's start with clear benefits. Firstly, the rotary engine has the most balanced design, and therefore practically does not cause high vibrations during operation. Secondly, this motor has a lighter weight and greater compactness, and therefore its installation is especially relevant for sports car manufacturers. In addition, the low weight of the unit made it possible for designers to achieve ideal weight distribution axle loads. Thus, a car with this engine became more stable and maneuverable on the road.

And, of course, the design space. Despite the same number of cycles of operation, the device of this engine is much simpler than that of a piston counterpart. To create a rotary motor, a minimum number of components and mechanisms was required.

However, the main trump card of this engine is not in the mass and low vibrations, but in high efficiency. Due to the special working principle rotary motor had more power and coefficient useful action.

Now for the disadvantages. They turned out to be much more than advantages. The main reason why manufacturers refused to buy such engines was their high fuel consumption. On average, for a hundred kilometers, such a unit spent up to 20 liters of fuel, and this, you see, is a considerable expense by today's standards.

Difficulty in manufacturing parts

In addition, it is worth noting the high cost of manufacturing parts for this engine, which was explained by the complexity of manufacturing the rotor. In order to this mechanism correctly passed the epitrochoidal curve, high geometric accuracy is needed (including for the cylinder). Therefore, in the manufacture of rotary engines, it is impossible to do without specialized expensive equipment and special knowledge in technical area. Accordingly, all these costs are pre-packaged in the price of the car.

Overheating and high loads

Also, due to the special design, this unit was often subject to overheating. The whole problem was the lenticular shape of the combustion chamber.

In contrast, classic internal combustion engines have a spherical chamber design. The fuel that burns in the lenticular mechanism is converted into thermal energy, which is consumed not only for the working stroke, but also for heating the cylinder itself. Ultimately, the frequent "boiling" of the unit leads to rapid wear and disable it.

Resource

Not only the cylinder endures heavy loads. Studies have shown that during the operation of the rotor, a significant part of the loads falls on the seals located between the nozzles of the mechanisms. They are subject to constant pressure drop, because maximum resource engine is no more than 100-150 thousand kilometers.

After that, the motor needs overhaul, the cost of which is sometimes equivalent to buying a new unit.

Oil consumption

Also, a rotary engine is very demanding on maintenance.

Its oil consumption is more than 500 milliliters per 1 thousand kilometers, which makes it necessary to fill in liquid every 4-5 thousand kilometers. If you do not replace it in time, the motor will simply fail. That is, the issue of servicing a rotary engine must be approached more responsibly, otherwise slightest mistake fraught with costly repairs to the unit.

Varieties

On this moment There are five varieties of these types of aggregates:

Rotary engine (VAZ-21018-2108)

The history of the creation of VAZ rotary internal combustion engines dates back to 1974. It was then that the first RPD design bureau was created. However, the first engine developed by our engineers had a similar design to the Wankel engine, which was equipped with imported NSU Ro80 sedans. The Soviet counterpart was named VAZ-311. This is the very first Soviet rotary engine. Working principle on VAZ cars of this motor has the same Wankel RPD action algorithm.

The first car on which these engines began to be installed was the VAZ modification 21018. The car practically did not differ from its "ancestor" - model 2101 - with the exception of the internal combustion engine used. Under the hood of the novelty was a single-section RPD with a capacity of 70 horsepower. However, as a result of research on all 50 model samples, numerous engine breakdowns were found, which forced the Volzhsky plant to abandon the use of of this type ICE on their cars for the next few years.

The main reason for the malfunctions of the domestic RPD was unreliable seals. However, Soviet designers decided to save this project by presenting the world with a new 2-section rotary engine VAZ-411. Subsequently, an internal combustion engine of the VAZ-413 brand was developed. Their main differences were in power. The first copy developed up to 120 horsepower, the second - about 140. However, these units were not included in the series again. The plant decided to put them only on official cars used in the traffic police and the KGB.

Motors for aviation, "eights" and "nines"

In subsequent years, the developers tried to create a rotary motor for domestic small aircraft, but all attempts were unsuccessful. As a result, the designers again took up the development of engines for passenger cars (now front-wheel drive) VAZ series 8 and 9. Unlike their predecessors, the newly developed VAZ-414 and 415 engines were universal and could be used on rear-wheel drive models of Volga and Moskvich cars. and so on.

Characteristics of the RPD VAZ-414

First this engine appeared on the "nines" only in 1992. Compared with its "ancestors", this motor had the following advantages:

• High specific power, which made it possible for the car to reach “hundred” in just 8-9 seconds.
• Great efficiency. From one liter of burnt fuel, it was possible to get up to 110 horsepower (and this without any forcing and additional boring of the cylinder block).
• High potential for forcing. At correct setting it was possible to increase the engine power by several tens of horsepower.
• High speed motor. Such an engine was able to work even at 10,000 rpm. Under such loads, only a rotary engine could function. The principle of operation of classic internal combustion engines does not allow them to be operated for a long time at high speeds.
• Relatively low fuel consumption. If the previous copies "ate" about 18-20 liters of fuel per "hundred", then this unit consumed only 14-15 in average operation.

The current situation with the RPD at the Volga Automobile Plant

All of the above engines did not gain much popularity, and soon their production was curtailed. In the future, the Volga Automobile Plant has no plans to revive the development of rotary engines. So the RPD VAZ-414 will remain a crumpled piece of paper in the history of domestic engineering.

So, we found out which rotary engine has the principle of operation and device.

Usually the "heart" of the machine is a cylinder-piston system, that is, based on reciprocating motion, but there is another option - rotary engine vehicles.

Cars with a rotary engine - the main difference

The main difficulty in the operation of internal combustion engines with classic cylinders is the conversion of the reciprocating motion of the pistons into torque, without which the wheels will not rotate. That is why, from the moment the first one was created, scientists and self-taught mechanics puzzled over how to make a motor with exclusively rotating nodes. The German nugget technician Wankel succeeded in this.

The first sketches were developed by him in 1927, after graduating from high school. In the future, the mechanic bought a small workshop and came to grips with his idea. The result of many years of work was a working model of a rotary internal combustion engine, created jointly with engineer Walter Freude. The mechanism turned out to be similar to an electric motor, that is, it was based on a shaft with a trihedral rotor, very similar to the Reuleaux triangle, which was enclosed in an oval-shaped chamber. The corners rest against the walls, creating a hermetic movable contact with them.

The cavity of the stator (case) is divided by the core into the number of chambers corresponding to the number of its sides, and for one revolution of the rotor the following are worked out: fuel injection, ignition, exhaust gas emission. In fact, of course, there are 5 of them, but two intermediate ones, fuel compression and gas expansion, can be ignored. In one complete cycle, 3 revolutions of the shaft occur, and given that two rotors are usually installed in antiphase, cars with a rotary engine have 3 times more power than classic cylinder-piston systems.

How popular is a rotary diesel engine?

The first cars on which the Wankel ICE was installed were the NSU Spider cars of 1964, with a power of 54 hp, which made it possible to accelerate vehicles up to 150 km / h. Further, in 1967, a bench version of the NSU Ro-80 sedan was created, beautiful and even elegant, with a narrowed hood and a slightly higher trunk. It never went into mass production. However, it was this car that prompted many companies to buy licenses for a rotary diesel engine. These included Toyota, Citroen, GM, Mazda. Nowhere did the novelty catch on. Why? The reason for this was its serious shortcomings.

The chamber formed by the walls of the stator and rotor significantly exceeds the volume of a classic cylinder, the fuel-air mixture is uneven. Because of what, even with the use of a synchronous discharge of two candles, it is not provided complete combustion fuel. As a result, the internal combustion engine is uneconomical and non-environmental. That is why, when the fuel crisis broke out, NSU, which made a bet on rotary engines, was forced to merge with Volkswagen, where the discredited Wankels were abandoned.

Mercedes-Benz produced only two cars with a rotor - C111 of the first (280 hp, 257.5 km / h, 100 km / h in 5 seconds) and the second (350 hp, 300 km / h, 100 km /h for 4.8 sec) generations. Chevrolet also released two trial cars Corvette, with a two-section engine for 266 hp. and with a four-section 390 hp, but everything was limited to their demonstration. For 2 years, starting in 1974, Citroen produced 874 Citroen car GS Birotor with a capacity of 107 hp, then they were withdrawn for liquidation, but about 200 remained with motorists. So, there is a chance to meet them today on the roads of Germany, Denmark or Switzerland, unless, of course, their owners were given a major overhaul of the rotary engine.

Mazda was able to establish the most stable production, from 1967 to 1972 1519 Cosmo cars were produced, embodied in two series of 343 and 1176 cars. During the same period, it was released in mass production Coupe Luce R130. Wankels began to be installed on all Mazda models without exception since 1970, including the Parkway Rotary 26 bus, which develops speeds of up to 120 km / h with a mass of 2835 kg. Around the same time, the production of rotary engines began in the USSR, however, without a license, and, therefore, they came up with their own minds using the example of a disassembled Wankel with NSU Ro-80.

The development was carried out at the VAZ plant. In 1976, the VAZ-311 engine was qualitatively changed, and six years later the VAZ-21018 brand with a 70 hp rotor began to be mass-produced. True, a piston internal combustion engine was soon installed on the entire series, since all the “wankels” broke during the run-in, and a replacement rotary engine was required. Since 1983, the VAZ-411 and VAZ-413 models for 120 and 140 hp began to roll off the assembly line. respectively. They were equipped with units of the traffic police, the Ministry of Internal Affairs and the KGB. Rotors are now exclusively handled by Mazda.

It is quite difficult to do anything on your own with the Wankel ICE. The most accessible action is the replacement of candles. On the first models, they were mounted directly into a fixed shaft, around which not only the rotor rotated, but also the body itself. Later, on the contrary, the stator was made immobile by installing 2 candles in its wall opposite the fuel injection and exhaust valves. Any other repair work if you are used to classic piston ICE are practically impossible.

In the Wankel engine, there are 40% fewer parts than in a standard ICE, the operation of which is based on a CPG (cylinder-piston group).

The shaft bearing liners are changed if the copper begins to show through, for this we remove the gears, replace them and press the gears again. Then we inspect the seals and, if necessary, change them too. When repairing a rotary engine with your own hands, be careful when removing and installing springs oil scraper rings, anterior and posterior differ in shape. The end plates are also replaced if necessary, and they must be installed according to the letter marking.

Corner seals are primarily mounted on the front side of the rotor, it is advisable to put them on green Castrol grease to fix them during assembly of the mechanism. After installing the shaft, rear corner seals are installed. When laying gaskets on the stator, lubricate them with sealant. Apexes with springs are inserted into the corner seals after the rotor is placed in the stator housing. IN last turn are lubricated with sealant on the gaskets of the front and rear sections before fastening the covers.

The idea of ​​​​a rotary engine is too tempting: when a competitor is very far from ideal, it seems that we are about to overcome shortcomings and get not a motor, but perfection itself ... Mazda was in captivity of these illusions right up to 2012, when the last model with rotary engine - RX-8.

The history of the creation of a rotary engine

The second name of a rotary engine (RPD) is a wankel (a kind of analogue of a diesel engine). It is Felix Wankel who today is credited with the laurels of the inventor of the rotary piston engine, and even a touching story is told about how Wankel went to his goal at the same time that Hitler was going to his own.

In fact, everything was a little different: a talented engineer, Felix Wankel really worked on the development of a new, simple engine internal combustion, but it was a different engine based on the co-rotation of the rotors.

After the war, Wankel was recruited by the German company NSU, which was mainly engaged in the production of motorcycles, to one of the working groups working on the creation of a rotary engine under the leadership of Walter Freude.

Wankel's contribution is extensive research on rotary valve seals. Basic scheme and the engineering concept belong to Freud. Although Wankel had a patent for dual rotation.

The first engine had a rotating chamber and a fixed rotor. The inconvenience of the design led to the idea to change the scheme in some places.

The first rotating rotor engine began operation in mid-1958. It differed little from its descendant of our days - except that the candles had to be moved to the body.

Soon the company announced that it had managed to create a new and very promising engine. Nearly a hundred car manufacturing companies have purchased licenses to produce this engine. A third of the licenses ended up in Japan.

RPD in the USSR

And here Soviet Union I didn't buy a license at all. The development of our own rotary engine began with the fact that they brought to the Union and dismantled german car Ro-80, which NSU began production in 1967.

Seven years later, a design bureau appeared at the VAZ plant, developing exclusively rotary piston engines. Through his work, in 1976, the VAZ-311 engine arose. But the first pancake turned out to be lumpy, and it was finalized for another six years.

First Soviet stock car with a rotary engine is the VAZ-21018, introduced in 1982. Unfortunately, already in the experimental batch, the motors of all the machines failed. They finalized another year, after which the VAZ-411 and VAZ 413 appeared, which were taken into service law enforcement agencies THE USSR. They were not particularly worried about fuel consumption and a short engine life, but they needed fast, powerful, but inconspicuous cars that could keep up with a foreign car.

RPD in the West

In the West, the rotary engine did not boom, and its development in the US and Europe ended with the fuel crisis of 1973, when gasoline prices soared, and car buyers began to ask about fuel-efficient models.

Considering that the rotary engine ate up to 20 liters of gasoline per hundred kilometers, its sales during the crisis fell to the limit.

The only country in the East that has not lost faith is Japan. But even there, manufacturers quickly lost interest in the engine, which did not want to improve. And in the end there was one steadfast tin soldier left - the Mazda company. In the USSR, the fuel crisis was not felt. The production of machines with RPD continued after the collapse of the Union. VAZ stopped doing RPD only in 2004. Mazda reconciled only in 2012.

Rotary motor features

The design is based on a triangular-shaped rotor, each of the faces of which has a bulge (). The rotor rotates in a planetary type around the central axis - the stator. At the same time, the vertices of the triangle describe a complex curve called an epitrochoid. The shape of this curve determines the shape of the capsule inside which the rotor rotates.

The rotary motor has the same four cycle duty cycle as its competitor, the piston motor.

Chambers are formed between the edges of the rotor and the walls of the capsule, their shape is variable crescent, which is the cause of some significant design flaws. To isolate the chambers from each other, seals are used - radial and end plates.

If we compare rotary internal combustion engine with a piston, the first thing that catches your eye is that in one revolution of the rotor the working stroke occurs three times, and the output shaft rotates three times faster than the rotor itself.

At RPD no gas distribution system which greatly simplifies its design. A high power density with a small size and weight of the unit are due to the absence of a crankshaft, connecting rods and other interfaces between cameras.

Advantages and disadvantages of rotary engines

Advantages

The rotary engine is good because consists of far fewer parts than its competitor - by 35-40 percent.

Two engines of the same power - rotary and piston - will differ greatly in size. Piston twice as big.

rotary motor does not experience a lot of load at high speeds even if you accelerate the car to a speed of more than 100 km / h in low gear.

A car with a rotary engine is easier to balance that gives increased machine stability on road.

Even the lightest Vehicle do not suffer from vibration, because RPD vibrates much less than the "piston". This is due to the greater balance of the RPD.

Flaws

The main disadvantage of a rotary engine motorists would call it small resource, which is a direct consequence of its design. Seals wear extremely quickly, as their working angle is constantly changing.


Motor test temperature fluctuations every cycle, which also contributes to the wear of the material. Add to this the pressure that is exerted on the rubbing surfaces, which is treated only by injecting oil directly into the manifold.

Worn seals causes leakage between the chambers, the pressure differences between which are too great. Because of this, the efficiency of the engine drops, and the harm to the environment grows.

crescent the shape of the chambers does not contribute to the completeness of fuel combustion, and the speed of rotation of the rotor and the short length of the working stroke are the reason for pushing out still too hot, not completely burned gases to the exhaust. In addition to the combustion products of gasoline, oil is also present there, which together makes the exhaust very toxic. Piston - brings less harm to the environment.

exorbitant appetites engine for gasoline have already been mentioned, and it "eats" oil up to 1 liter per 1000 km. And once you forget about the oil and you can get into a major repair, if not an engine replacement.

High price- due to the fact that for the manufacture of the motor you need high-precision equipment and very high quality materials.

As you can see, the rotary engine is full of flaws, but the piston engine is also imperfect, so the competition between them did not stop for so long. Is it over forever? Time will show.

We tell how a rotary engine is arranged and works.

A rotary piston engine or Wankel engine is a motor where planetary circular motions are carried out as the main working element. This is a fundamentally different type of engine, different from piston counterparts in the ICE family.

The design of such a unit uses a rotor (piston) with three faces, externally forming a Reuleaux triangle, carrying out circular movements in a cylinder of a special profile. Most often, the surface of the cylinder is made along an epitrochoid (a flat curve obtained by a point that is rigidly connected to a circle that moves along outside another circle). In practice, you can find a cylinder and a rotor of other shapes.

Components and principle of operation

The device of the RPD type engine is extremely simple and compact. A rotor is installed on the axis of the unit, which is firmly connected to the gear. The latter is coupled to the stator. The rotor, which has three faces, moves along an epitrochoidal cylindrical plane. As a result, the changing volumes of the working chambers of the cylinder are cut off using three valves. Sealing plates (end and radial type) are pressed against the cylinder by the action of gas and due to the action of centripetal forces and band springs. It turns out 3 isolated chambers of different volume sizes. Here, the processes of compressing the incoming mixture of fuel and air, expanding gases that put pressure on work surface rotor and cleaning the combustion chamber from gases. Transferred to the eccentric axle Roundabout Circulation rotor. The axle itself is on bearings and transmits the torque to the transmission mechanisms. In these motors, the simultaneous operation of two mechanical pairs is carried out. One, which consists of gears, regulates the movement of the rotor itself. The other converts the rotating motion of the piston into the rotating motion of the eccentric axle.

Rotary Piston Engine Parts

The principle of operation of the Wankel engine

Using the example of engines installed on VAZ vehicles, the following can be mentioned specifications:
- 1.308 cm3 - working volume of the RPD chamber;
- 103 kW / 6000 min-1 - rated power;
- 130 kg engine weight;
- 125,000 km - engine life until its first complete repair.

mixture formation

In theory, RPD uses several types of mixture formation: external and internal, based on liquid, solid, gaseous fuels.
Regarding hard species of fuel, it should be noted that they are initially gasified in gas generators, as they lead to increased ash formation in cylinders. Therefore, gaseous and liquid fuels have become more widespread in practice.
The very mechanism of mixture formation in Wankel engines will depend on the type of fuel used.
When using gaseous fuel, its mixing with air occurs in a special compartment at the engine inlet. combustible mixture is delivered to the cylinders ready-made.

From liquid fuel, the mixture is prepared as follows:

1. Air is mixed with liquid fuel before entering the cylinders where the combustible mixture enters.
2. Liquid fuel and air enter the engine cylinders separately, and already inside the cylinder they are mixed. The working mixture is obtained by contact with residual gases.

Accordingly, the fuel-air mixture can be prepared outside the cylinders or inside them. From this comes the separation of engines with internal or external mixture formation.

RPD features

Advantages

Advantages of rotary piston engines compared to standard gasoline engines:

- Low vibration levels.
In motors of the RPD type, there is no conversion of reciprocating motion into rotational, which allows the unit to withstand high speeds with less vibration.

— Good dynamic characteristics.
Thanks to its design, such a motor installed in the car allows it to be accelerated above 100 km / h at high speeds without excessive load.

— Good performance specific power at low weight.
Due to the absence in the design of the engine crankshaft and connecting rods, a small mass of moving parts in the RPD is achieved.

- In engines of this type, there is practically no lubrication system.
Oil is added directly to the fuel. The fuel-air mixture itself lubricates friction pairs.

- The rotary piston type motor has small overall dimensions.
Installed rotary piston motor maximizes usable space engine compartment car, evenly distribute the load on the axles of the car and better calculate the location of the elements of the gearbox and assemblies. For example, four stroke engine the same power will be twice as much as a rotary engine.

Disadvantages of the Wankel engine

— Quality of engine oil.
When operating this type of engine, it is necessary to pay due attention to the quality composition of the oil used in Wankel engines. The rotor and the engine chamber inside have a large contact area, respectively, the engine wears out faster, and such an engine constantly overheats. Irregular oil changes cause great damage to the engine. The wear of the motor increases many times due to the presence of abrasive particles in the used oil.

— The quality of the spark plugs.
The operators of such engines have to be particularly demanding on the quality of the composition of the spark plugs. In the combustion chamber, due to its small volume, extended shape and high temperature, the process of ignition of the mixture is difficult. The consequence is an increased operating temperature and periodic detonation of the combustion chamber.

— Materials of sealing elements.
A significant flaw in the RPD-type motor can be called the unreliable organization of seals between the gaps between the chamber where the fuel burns and the rotor. The device of the rotor of such a motor is rather complicated, therefore seals are required both along the edges of the rotor and along the side surface in contact with the engine covers. Surfaces that are subject to friction must be constantly lubricated, which results in increased consumption oils. Practice shows that an RPD-type motor can consume from 400 g to 1 kg of oil for every 1000 km. The environmental performance of the engine is reduced, as the fuel burns together with the oil, resulting in environment a large amount of harmful substances are emitted.

Due to their shortcomings, such motors are not widely used in the automotive industry and in the manufacture of motorcycles. But on the basis of RPD, compressors and pumps are manufactured. Aeromodellers often use these engines to build their models. Due to the low requirements for efficiency and reliability, designers do not use a complex sealing system in such motors, which significantly reduces its cost. The simplicity of its design allows it to be integrated into an aircraft model without any problems.

Efficiency of rotary piston design

Despite a number of shortcomings, studies have shown that the overall efficiency of the Wankel engine is quite high by modern standards. Its value is 40 - 45%. For comparison, in piston internal combustion engines, the efficiency is 25%, in modern turbodiesels - about 40%. Most high efficiency piston diesel engines is 50%. To date, scientists continue to work to find reserves to improve the efficiency of engines.

final work efficiency The motor consists of three main parts:

1. Fuel efficiency (an indicator characterizing the rational use of fuel in the engine).

Research in this area shows that only 75% of the fuel burns out in full. There is an opinion that this problem solved by separating the processes of combustion and expansion of gases. It is necessary to provide for the arrangement of special chambers under optimal conditions. Combustion should take place in a closed volume, subject to an increase temperature indicators and pressure, the expansion process should take place at low temperatures.

1. Mechanical efficiency (characterizes the work, the result of which was the formation of the torque of the main axis transmitted to the consumer).

About 10% of the engine's work is spent on setting in motion auxiliary units and mechanisms. This defect can be corrected by making changes to the engine device: when the main moving working element does not touch the stationary body. A constant torque arm must be present along the entire path of the main working element.

1. Thermal efficiency (an indicator reflecting the amount of thermal energy generated from the combustion of fuel, which is converted into useful work).

In practice, 65% of the received thermal energy escapes with exhaust gases during external environment. A number of studies have shown that it is possible to achieve an increase in thermal efficiency in the case when the design of the motor would allow the combustion of fuel in a heat-insulated chamber so that maximum temperatures are reached from the very beginning, and at the end this temperature is reduced to minimum values ​​by turning on the vapor phase.

The current state of the rotary piston engine

Significant technical difficulties arose in the way of mass application of the engine:
– development of a high-quality work process in an unfavorable chamber;
- ensuring the tightness of the sealing of working volumes;
– designing and creating a structure of body parts that will reliably serve the entire life cycle of the engine without warping with uneven heating of these parts.
As a result of the huge research and development work done, these firms managed to solve almost all the most difficult technical problems on the way to the creation of RPDs and enter the stage of their industrial production.

First mass car NSU Spider with RPD began to be produced by NSU Motorenwerke. Due to frequent overhauls of engines due to the above technical problems at an early stage in the development of the design of the Wankel engine, taken by NSU warranty obligations led it to financial ruin and bankruptcy and the subsequent merger with Audi in 1969.
Between 1964 and 1967, 2375 cars were produced. In 1967 the Spider was discontinued and replaced by the NSU Ro80 with a second generation rotary engine; in ten years of Ro80 production, 37,398 cars were produced.

Mazda engineers have dealt with these problems most successfully. It remains the only mass manufacturer of machines with rotary piston engines. The modified engine has been serially installed on the Mazda RX-7 since 1978. Since 2003, succession has taken Mazda model RX-8, it is currently the mass and only version of the car with a Wankel engine.

Russian RPDs

The first mention of a rotary engine in the Soviet Union dates back to the 60s. Research work on rotary piston engines began in 1961, by the relevant decree of the Ministry of Automotive Industry and the Ministry of Agriculture of the USSR. An industrial study with a further conclusion to the production of this design began in 1974 at the VAZ. specifically for this, a Special Design Bureau for Rotary Piston Engines (SKB RPD) was created. Since it was not possible to buy a license, the serial Wankel from NSU Ro80 was disassembled and copied. On this basis, the VAZ-311 engine was developed and assembled, and this significant event took place in 1976. At VAZ, they developed a whole line of RPDs from 40 to 200 strong engines. The finalization of the design dragged on for almost six years. It was possible to solve a number of technical problems associated with the performance of gas and oil seals, bearings, to debug an efficient workflow in an unfavorable chamber. VAZ presented its first production car with a rotary engine under the hood to the public in 1982, it was the VAZ-21018. The car was externally and structurally like all models of this line, with one exception, namely, under the hood there was a single-section rotary engine with a capacity of 70 hp. The duration of development did not prevent embarrassment from happening: on all 50 experimental machines, engine breakdowns occurred during operation, forcing the plant to install a conventional piston engine in its place.

VAZ 21018 with rotary piston engine

Having established that the cause of the malfunction was the vibration of the mechanisms and the unreliability of the seals, the designers undertook to save the project. Already in the 83rd, two-section VAZ-411 and VAZ-413 appeared (with a capacity of 120 and 140 hp, respectively). Despite the low efficiency and short resource, the scope of the rotary engine was still found - the traffic police, the KGB and the Ministry of Internal Affairs needed powerful and inconspicuous vehicles. Equipped with rotary engines, Zhiguli and Volga easily overtook foreign cars.

Since the 80s of the 20th century, SKB has been fascinated by a new topic - the use of rotary engines in a related industry - aviation. The departure from the main industry of RPD application has led to the fact that for front wheel drive cars the VAZ-414 rotary engine was created only by 1992, and it was brought to completion for another three years. In 1995, the VAZ-415 was submitted for certification. Unlike its predecessors, it is universal, and can be installed under the hood of both rear-wheel drive (classic and GAZ) and front-wheel drive cars (VAZ, Moskvich). The two-section "Wankel" has a working volume of 1308 cm 3 and develops a power of 135 hp. at 6000 rpm. "Ninety-ninth" he accelerates to hundreds in 9 seconds.

Rotary piston engine VAZ-414

At the moment, the project for the development and implementation of the domestic RPD is frozen.

Below is a video of the device and the operation of the Wankel engine.

Main difference internal device and the principle of operation of a rotary engine from an internal combustion engine is the complete absence of motor activity, while it is possible to achieve high engine speeds. The rotary engine, or otherwise the Wankel engine, has a number of other advantages, which we will consider in more detail.

The general principle of the design of a rotary engine

The RPD is clad in an oval body for optimal placement of the triangular rotor. Distinctive feature rotor in the absence of connecting rods and shafts, which greatly simplifies the design. In fact, the key parts of the RD are the rotor and stator. The main motor function in this type of motor is carried out due to the movement of the rotor located inside the housing, which is similar to an oval.

The principle of operation is based on the high-speed movement of the rotor in a circle, as a result, cavities are created to start the device.

Why are rotary engines not in demand?

The paradox of a rotary engine lies in the fact that, for all its simplicity of design, it is not as in demand as an internal combustion engine, which has very complex design features and difficulties in carrying out repair work.

Of course, the rotary engine is not without drawbacks, otherwise it would be widely used in modern automotive industry, and perhaps we would not have known about the existence of an internal combustion engine, because the rotary one was designed much earlier. So why complicate the design so much, let's try to figure it out.

Obvious shortcomings of the rotary motor can be considered the lack of reliable sealing in the combustion chamber. This is easily explained by the design features and operating conditions of the motor. In the course of intense friction of the rotor with the cylinder walls, uneven heating of the body occurs and, as a result, the metal of the body expands from heating only partially, which leads to pronounced violations of the sealing of the body.

To enhance the hermetic properties, especially under the condition of a pronounced temperature difference between the chamber and the intake or exhaust system, the cylinder itself is made of different metals and placed in different parts of the cylinder to improve tightness.

To start the motor, only two candles are used, this is due to the design features of the motor, which make it possible to produce 20% more efficiency, in comparison with an internal combustion engine, for the same period of time.

Zheltyshev rotary engine - principle of operation:

Benefits of a rotary engine

With small dimensions, it is capable of developing high speed, but there is a big minus in this nuance. Despite its small size, it is the rotary engine that consumes a huge amount of fuel, but the engine's service life is only 65,000 km. So, an engine of only 1.3 liters consumes up to 20 liters. fuel per 100 km. Perhaps this was the main reason for the lack of popularity of this type of motor for mass consumption.

The price of gasoline is always considered topical issue humanity, given that the world's oil reserves are located in the Middle East, in a zone of constant military conflicts, gasoline prices remain quite high, and in the short term there are no trends to reduce them. This leads to the search for solutions for the minimum consumption of resources without sacrificing power, which is the main argument in favor of the internal combustion engine.

All this together determined the position of rotary engines, as suitable option for sports cars. However, the world-famous car manufacturer Mazda continued the work of the inventor Wankel. Japanese engineers are always trying to get the most out of unclaimed models through modernization and use innovative technologies, which allows us to maintain a leading position in the global automotive market.

The principle of operation of the Akhriev rotary engine on the video:

The new model "Mazda", equipped with a rotary engine, is not inferior in power to the advanced German models, delivering up to 350 horsepower. At the same time, fuel consumption was incomparably high. Mazda design engineers had to reduce the power to 200 horsepower, which made it possible to normalize fuel consumption, but the compact size of the engine made it possible to give the car additional advantages and compete with European car models.

In our country, rotary engines have not taken root. There were attempts to install them on the transport of specialized services, but this project was not funded in the proper amount. Therefore, all successful developments in this direction belong to Japanese engineers from the Mazda company, which intends to soon show new model car with upgraded engine.

How a Wankel rotary motor works on video

The principle of operation of a rotary engine

The RPD works by rotating the rotor, so power is transferred to the gearbox through the clutch. The transforming moment consists in the transfer of fuel energy to the wheels due to the rotation of the rotor made of alloy steel.

The mechanism of operation of a rotary piston engine:

• fuel compression;
• fuel injection;
• oxygen enrichment;
• combustion of the mixture;
• release of fuel combustion products.

How a rotary engine works is shown in the video:

The rotor is attached to special device, during rotation, it forms cavities independent of each other. The first chamber is filled with an air-fuel mixture. Subsequently, it is thoroughly mixed.

Then the mixture passes into another chamber, where compression and ignition takes place, thanks to the presence of two candles. Subsequently, the mixture moves to the next chamber, parts of the processed fuel that exit the system are displaced from it.

This is how a complete cycle of operation of a rotary piston engine occurs, based on three cycles of work in just one revolution of the rotor. It was the Japanese developers who managed to significantly modernize the rotary engine and install three rotors in it at once, which can significantly increase power.

The principle of operation of the Zuev rotary engine:

Today, the advanced two-rotor engine is comparable to a six-cylinder internal combustion engine, and the three-rotor engine is as powerful as a 12-cylinder internal combustion engine.

Do not forget about compact size engine and the simplicity of the device, allowing, if necessary, to carry out repairs or complete replacement main motor units. Thus, Mazda engineers managed to give a second life to this simple and productive device.