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 such a motor in which the moving parts only rotated. 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 man did not receive any specialty or higher education. Let us consider further the Wankel rotary-piston engine.
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 died. Because of this, Wankel had to leave school in a gymnasium and get a job as an assistant seller in a book shop at a publishing house. Because of this, he was addicted to reading. Felix studied the technical characteristics of engines, automotive, mechanics independently. Knowledge he drew from books that were sold in the shop. It is believed that the later implemented Wankel engine (more precisely, the idea of its creation) visited in a dream. It is not known whether this is true or not, but one can say for sure that the inventor had uncommon abilities, a burden to mechanics and a peculiar 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 had to develop prototypes of aircraft engines. However, until the very end of World War II, not a single Wankel rotary engine was sent to serial production. This was probably due to the fact that it took quite a long time to bring the design to a serviceable condition and set up mass production.
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 Frede (lead engineer at NSU), the rotary-piston engine was first put on the car. Motor was installed on NSU Prinz. However, the original design was very far from perfect. It was so complicated that even to replace the spark plug it was necessary to disassemble almost the entire motor. In addition, the design was very unreliable, uneconomical and had a very low efficiency. The Wankel engine in connection with this did not go to the series. Cars went to the conveyor with a traditional engine. Nevertheless, the rotary-piston engine proved not only the right to exist, but also demonstrated an impressive potential for that time. Prospects for its use were so attractive that design engineers could not stop anything. The inventor himself understood that his offspring needed improvement, he strove to ensure that both the operation and the repair of the engine caused as little difficulty as possible. From that moment, active work began to bring the motor to operational excellence.
Wankel engine: design
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 the time. So, the first company to buy the license was Curtiss-Wright. A year later, such famous companies as Mazda, Friedrich Krupp, MAN, and Daimler-Benz began to use the invention. For a fairly short period of time, the license acquired about one hundred companies, including world-famous ones: Ford, BMW, Porsche, Rolls-Royce.
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 allows you to create a comfortable and quite spacious interior. Improved engine models are capable of high power with sufficiently economical fuel consumption. For example, a modern engine with a volume of 1300 cm 3 has 220 liters. with. If you equip the Wankel engine with a turbocharger, you can get a power of up to 350 liters. with. Another advantage of the design is a very low level of vibrations and noise. The Wankel engine is mechanically balanced. Reducing noise and vibration is achieved by a small number of parts (they are 40% less than in traditional engines). It is also worth noting the dynamic characteristics of the motor. In low gear without special load, you can accelerate the car to 100 km / h at high revs. In the design of the motor there is no mechanism that converts the reciprocating movement into rotational. Due to this, the Wankel engine can withstand high speed in comparison with traditional internal combustion engines.
The end of euphoria
Disadvantages of the RPD: fragility and unreliability
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 emissions
This is another disadvantage of the RAP. In comparison with traditional engines, the Wankel engine emits fewer oxides of nitrogen, but many times more hydrocarbons, due to incomplete combustion of fuel. Mazda engineers quickly found an effective solution to the problem. Specialists have created a “thermal reactor”. It is “afterburning” of hydrocarbons. Mazda R 100 was the first car in which this element was applied. In 1968, another model with a “thermal reactor” was released - the Familia Presto Rotary. This car, one of the few, immediately passed a fairly stringent environmental test, put forward by the United States 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 RPD on sports cars. And VAZ produced the Oka mololitrazhny models, in spite of the fact that it would be more expedient to put dynamic engines on more high-speed cars. Anyway, there were several Oka minicars with RPD on domestic roads. By 1998, finally, the preparation of a civilian version of the two-cylinder 1.3-liter rotary engine was completed. It was installed on the model VAZ 2107-2109 and 2105.
Why are the leading manufacturers of the world still not finally switched to the production of cars with RAP? The fact is that for the manufacture of such motors is needed, first of all, a very accurate technology, which includes many different nuances. Not every, even a large company, can go the way of Mazda. In addition, the case in the equipment. For the release of the Wankel engine, high-precision machines are needed for grinding surfaces with epitrochoid. For equipment that is used in factories today, such work is quite feasible. Today, only Mazda is engaged in serious studies of RPD. The company's engineers are constantly improving the design, solve many different problems. The rotor engines manufactured in Japan comply with internationally accepted standards for reliability, fuel consumption and environmental friendliness.