Who Invented the Wankel Engine?
Felix Wankel, a German motor engineer, invented the rotary piston engine which bears his name. Deprived of a university education when his family’s fortune vanished in the German inflation of 1919-20, he went in for a car repairing and set up his own business in 1924 at the age of 22. Soon he began work at designing a rotary piston engine, an idea which had attracted engineers since the invention of the steam engine.
From 1934 to 1936 his research was backed by B.M.W. and from 1936 to 1945 by the German Air force. In 1951 he established his own research institute and financed it by working as a consultant. Wankel succeeded in discovering the secrets of effective seals between the rotating pistons and the casing. He also discovered the geometrical form of an engine that could carry out the four-stroke cycle in one chamber without valves, giving a useful high compression ratio.
His engine ran successfully for the first time at N.S.U. Motorenwerke in February, 1957. N.S.U. began limited production of Wankel engine for cars in 1963, and went into large-scale production in 1967. The rotary piston engine challenges the usual internal combustion engine, using reciprocating pistons, because it offers reduced size, weight, vibration, noise and production costs for comparable thermal efficiency. It is considered suitable for industrial, marine and aeronautical uses.
In 1951, NSU Motorenwerke AG in Germany began development of the engine, with two models being built. The first, the DKM motor, was developed by Felix Wankel. The second, the KKM motor, developed by Hanns Dieter Paschke, was adopted as the basis of the modern Wankel engine.
The basis of the DKM type of motor was that both the rotor and the housing spun around on separate axes. The DKM motor reached higher revolutions per minute and was more naturally balanced. However, the engine needed to be stripped to change the spark plugs and contained more parts. The KKM engine was simpler, having a fixed housing.
The first working prototype, DKM 54, produced 21 hp (16 kW) and ran on February 1, 1957, at the NSU research and development department Versuchsabteilung TX. The KKM 57 (the Wankel rotary engine, Kreiskolbenmotor) was constructed by NSU engineer Hanns Dieter Paschke in 1957 without the knowledge of Felix Wankel, who later remarked “you have turned my race horse into a plow mare”.
The design was conceived by German engineer Felix Wankel. Wankel received his first patent for the engine in 1929. He began development in the early 1950s at NSU, and completed a working prototype in 1957. NSU subsequently licensed the design to companies around the world, who have continually added improvements. The engines produced are of spark ignition, with compression ignition engines only in research projects.
The Wankel engine has the advantages of compact design and low weight over the most commonly used internal combustion engine employing reciprocating pistons. These advantages have given rotary engine applications in a variety of vehicles and devices, including: automobiles, motorcycles, racing cars, aircraft, go-karts, jet skis, snowmobiles, chainsaws, and auxiliary power units. The point of power to weight has been reached of under one pound weight per horsepower output.
The Wankel engine is a type of internal combustion engine using an eccentric rotary design to convert pressure into rotating motion. In contrast to the more common reciprocating piston designs, the Wankel engine delivers advantages of simplicity, smoothness, compactness, high revolutions per minute, and a high power-to-weight ratio primarily due to the fact that it produces three power pulses per revolution compared to one per revolution in a two-stroke engine and one per two revolutions in a four-stroke engine.
The engine is commonly referred to as a rotary engine, although this name also applies to other completely different designs, primarily aircraft engines with their cylinders arranged in a circular fashion around the crankshaft. All parts rotate consistently in one direction, as opposed to the common reciprocating piston engine, which has pistons violently changing direction. The four-stage cycle of intake, compression, ignition, and exhaust occur each revolution at each of the three rotor tips moving inside the oval-like epitrochoid-shaped housing, enabling the three power pulses per revolution. The rotor is similar in shape to a Reuleaux triangle with sides that are somewhat flatter.