The main types of internal combustion engines and steam engines have a common drawback. It consists in that the reciprocating movement requires conversion into a rotary movement. This, in turn, causes poor performance and fairly high wear parts of the mechanism included in different types of engines. Quite a lot of people thought about creating a motor in which moving elements only revolved. However, only one person managed to solve this problem. Felix Wankel - a self-taught mechanic - became the inventor of a rotary piston engine. During his life this person has not received any specialty or higher education. Let us consider in more detail the rotor-piston engine of Wankel.
Brief biography of the inventor
Felix G. Wankel was born in 1902, on August 13, in the small town of Lahr (Germany). In the First World father of the future inventor was lost. Because of this, Vankel had to drop out of school at the gymnasium and get a job as an assistant to a seller in a bookstore selling shop. Thanks to this he was addicted to reading. Felix studied the technical characteristics of engines, automotive, mechanics themselves. Knowledge he drew from the books that were sold in the shop. It is believed that the realized later scheme of the Wankel engine (more precisely, the idea of its creation) visited in a dream. It is not known whether this is true or not, but it can be precisely said that the inventor possessed extraordinary abilities, a craving for mechanics and a unique look at many things.
The first types of engines
The inventor, realizing how you can implement all 4-cycle conventional motor rotation, started designing. In 1924, Wankel established a small workshop. She also played the role of the laboratory. It was here that Felix Wankel began to study rotary-piston system. In 1936, the model gathered by the inventor, interested in the company “BMW”. Wankel received the money, he was given a private lab in Lindau. There he was to develop prototypes of aircraft engines. However, until the very end of the Second World War, no single Wankel rotary engine was sent to mass production. Probably, this was due to the fact that bringing the structure up to a usable state and adjusting the mass production required a lot of time
After the defeat of fascism, the laboratory was closed and all the equipment was transported to France. As a result, the Wankel was left without a job. This was the result of his former membership in the national socialist party. But after a short period of time by Felix invited in the company of NSU as a design engineer. This company at that time was considered the oldest manufacturer of automobiles and motorcycles.
In 1957, thanks to the support of Walter Fred (lead engineer at NSU), the rotary piston engine was first put on the car. The motor was installed on the NSU Prinz. However, the original design was very far from perfect. It was so complicated that even for the replacement of the candles it was necessary to disassemble almost the entire motor. In addition, the design was very unreliable, uneconomic and had very low efficiency. Engine Wankel in this regard did not go to the series. Cars went to the conveyor with a traditional ICE. Nevertheless, the rotary piston engine proved not only the right to exist, but also demonstrated an impressive potential for that time. The prospects for its use were so attractive that the design engineers could not stop anything. The inventor himself understood that his offspring needed improvement, he wanted to ensure that both the functioning and repair of the engine caused as little difficulty as possible. From this moment, active work began to bring the engine to operational perfection.
Wankel engine: construction
What is the motor? In the center of the rotor has a circular opening. It is covered inside with teeth like the gear. Is inserted into the hole of the shaft with a smaller diameter. It also has teeth. They prevent slippage of the shaft. The relationship of the diameters are chosen in such a way as to move the vertices of the triangles was carried out by one closed curve. It is called “epitrochoid”. The objective of the Wankel was to begin to understand that such a mechanism is possible. Then he had everything exactly right and calculate. As a result, the piston is made in the shape of a reuleaux triangle, cuts off three chambers of variable position and extent.
The design characteristics of the engine is considerably better compared to conventional motors. In particular, the sealing of the chambers is provided by radial and end sealing plates. They cling to the “cylinder” by the band of springs, gas pressure and centrifugal forces. Special attention should be paid to engine performance, in terms of performance. For the whole cycle shaft makes 3 complete turns. In a normal piston motor such a result can be achieved with the use of six cylinders.
The introduction of industry
After the first successful demonstration in 1957, the Wankel engine interested the largest auto-giants of that time. So, the first company that bought the license was Curtiss-Wright. A year later, the invention began to use such well-known enterprises as Mazda, Friedrich Krupp, MAN and Daimler-Benz. For a fairly short period of the license, about a hundred companies, including those with a worldwide reputation: Ford, BMW, Porsche, Rolls-Royce, acquired.
What advantages has a Wankel engine? The principle of operation of the motor lies in the fact that the implementation of any four-stroke cycle is carried out without the use of a timing mechanism. Due to this considerably simplified design of the motor. In a conventional 4-stroke piston engine in about a thousand items more. The great interest of the largest automotive enterprises was caused by a potential design. Obvious advantages is the ease of production, simple engine repair, compactness and light weight. All this helps to improve the handling of the machine, facilitates the location of the transmission. The compactness of the motor makes it possible to create a comfortable and fairly spacious interior. Advanced engine models are able to develop high power with a fairly economical fuel consumption. For example, a modern engine with a volume of 1300 cm 3 has 220 liters. from. If you equip the Wankel engine turbocharger, you can get power up to 350 liters. from. Another advantage of the design is a very low level of vibration and noise. Wankel's engine is mechanically balanced. Reducing the level of noise and vibration is achieved by a small number of parts (40% less than in traditional engines). It is also worth noting the dynamic characteristics of the motor. On a low gear without a special load, you can accelerate the car to 100 km / h at high rpm. In the design of the motor there is no mechanism that converts the reciprocating motion into rotational motion. Due to this Wankel engine can withstand high revs in comparison with traditional ICE.
The end of euphoria
Disadvantages of the RAP: fragility and insecurity
Along with the advantages, rotary engines have significant disadvantages. In the first place, they were very short-lived. So, one of the first models of the RAPS during the tests, has developed the entire online in 2 hours. A more successful prototype was able to withstand 100 hours. However, this does not provide normal operation of the machine. The main problem was the uneven wear of the inner surface of the chamber. During the work it was formed by transverse grooves. They received a very eloquent title: “mark of the devil”. After receiving the license, the company Mazda has formed a special Department which was engaged in the improvement of the motor. It soon became clear that during rotation of the rotor the plugs located on top of it, begin to vibrate. Because of this, and these furrows. Today the problem of durability and reliability solved. This is used in the production of high-quality flooring, including ceramic.
High exhaust toxicity
This is another drawback of the RAP. In comparison with traditional engines, the Wankel engine produces less nitrogen oxides, but many times more hydrocarbons, which is due to incomplete combustion of fuel. Mazda engineers quickly found an effective solution to the problem. Specialists have created a "thermal reactor". In it, "afterburning" of hydrocarbons takes place. Mazda R 100 was the first car in which this element was applied. In 1968, another model was released with a "thermal reactor" - Familia Presto Rotary. This car, one of the few, immediately passed a fairly stringent environmental check, put forward by the US in 1970 for imported vehicles.
Is another problem for the RAPS. It partly follows from described above. Fuel consumption in the standard the RPD is much higher than the ice. This problem was again solved by the specialists of Mazda. Introducing a range of measures, including recycling of the carb and thermal, the addition of the exhaust system heat exchanger, the creation of a new ignition and the development of catalytic convector, engineers have reduced consumption by 40%. It allowed to produce in 1978, the model RX-7.
In addition, the company Mazda, cars with RAP produced “AVTOVAZ”. In 1974 the plant was formed special design Bureau. In Togliatti began construction of the shops for serial production of the RAP. Due to the fact that it was originally envisaged that the WHA would copy Western technology, it was decided to establish the reproduction of the engine of Mazda. It is absolutely not taken into account long-term developments of the domestic institutions of the motor.
Special orders breathed a second life in the design office. The Vase began to produce engines for cars and water sports. The car began frequently to win the first place. Sports officials, in turn, were forced to prohibit the use of RAP. In 1987 to replace Pospelova (the head of design Department) came Shnyakin. He disliked ground transportation, tending more to aviation. Since the beginning of his leadership SKB redeveloped its activity on the production of engines for flying machines. It was a wrong strategy because the aircraft in the country produced a lot less than cars. The same factory made a profit mainly from the sale of automotor. The next mistake was the reorientation to low-power engines. The Japanese set the RAP on sports cars. A VAZ produced molokotrazhnye model "Oka", despite the fact that it would be more expedient to set dynamic motors on more high-speed cars. Anyway, on domestic roads was a few minicars "Oka" with the RPD. By 1998, finally, the civil version of the twin-cylinder 1.3-liter rotor engine was completed. It was installed on the model VAZ 2107-2109 and 2105.
Why are the world's leading manufacturers still not finally switched to the production of cars with RPD? The fact is that for the manufacture of such motors, first of all, a very precise technology is needed, which includes a variety of various nuances. Not everyone, even a large company, can follow the path of Mazda. In addition, the matter is in the equipment. For the production of the Wankel engine, high-precision machines are needed to grind surfaces with an epitrochoid. For equipment that is used today in factories, such work is quite feasible. Today, only R \u0026 D is doing Mazda. The engineers of the company constantly improve the design, solve many different problems. Available in Japan, rotary engines are consistent with the world's standards for reliability, fuel consumption and environmental friendliness.