Felix Wankel

Felix Wankel

Felix Wankel

German engineer Felix Wankel is best known for his invention of the Wankel engine. The Wankel engine is a gasoline-powered engine that is more powerful than the engines usually used in automobiles.

Felix Wankel (1902-1988), German engineer, best known for inventing the Wankel engine. Sometimes called the Wankel rotary engine, the Wankel engine uses a turning rotor inside a housing instead of pistons to provide power. It is more powerful and easier to maintain than a traditional internal-combustion engine of the same size.

Born the son of a forestry official in the Black Forest of Germany, Wankel never pursued a higher education. He did, however, show great skills in engineering and mathematics as well as an intense interest in vehicle propulsion. He began developing an engine around 1927, having in mind a novel design for gasoline-powered, internal-combustion engines. He received his first patent in 1929, for plans he made for a rotary engine.

The main parts of Wankel’s engine are a roughly cylindrical chamber and a triangular rotor with rounded edges. The chamber’s cross-section is actually an ellipse, or an elongated circle, instead of a perfect circle. The chamber has two openings on one of the ellipse’s long sides. One allows fuel to flow into the chamber and the other allows exhaust to escape. A spark plug, a device that uses a strong electric current to produce a spark between two electrodes, is centered on the other long side of the chamber. The rotor’s corners fit snugly against the sides of the chamber, effectively dividing the chamber into three parts. As the rotor turns, it draws in fuel in one chamber, compresses the fuel until the spark plug ignites the fuel and burns it in the second chamber, and allows the byproducts of combustion to escape from the third chamber. The burning, expanding fuel gases forces the rotor to turn. The rotor is usually connected directly to a driveshaft. The engine’s simplicity makes it lighter and more powerful than a traditional Otto-cycle internal-combustion engine. However, it uses fuel faster than an equivalent Otto-cycle engine, and it releases more exhaust.

Wankel joined the National Socialist German Workers' Party (Nationalsozialistische Deutsche Arbeiterpartei, or NSDAP) in the 1920s but left the party in 1932, before the Nazis came to power. Conflicts with local Nazi officials led to his arrest and imprisonment for several months in 1933. After his release, he worked for the German Aeronautical Research Establishment, where he refined his rotary piston engine design. When the Allies invaded Germany in 1945 during the final stage of World War II, Wankel was captured and held as a prisoner of war in France until 1946.

After his release, it took Wankel several years to rebuild a research program. He gained the support of the German motorcycle manufacturer Neckarsulm Strickmaschinen Union (Neckarsulm Knitting-machine Union, or NSU) in 1951. Wankel finally produced a fully functional prototype of a rotary engine in 1956. In 1957 he formed a company called Wankel GmbH to license the design of his engine, and other companies paid Wankel GmbH for the right to used the rotary engine. Wankel sold his company in 1971. The company now builds rotary engines, used mostly for aircraft and go-carts. Wankel created Technische Entwicklungsstelle (Center for Technical Advancement, or TES) in 1976 as a research institute. German industrial company Daimler-Benz bought TES in 1986.

Major companies in several countries commercially developed the Wankel engine. The German manufacturer NSU used the engine in boats and several models of cars. The NSU used the engine in its R0 80 luxury sedan in the 1960s, but it showed problems of high fuel consumption and exhaust pollution. The Japanese automobile maker Mazda used it in sports cars, most notably the RX-7, from the 1970s to the 1990s. The Wankel engine has also been used by high-performance motorcycle makers.

Wider use of the Wankel engine remains possible if the high fuel consumption and exhaust pollution problems can be resolved. The Wankel engine is still the most radical innovation in hydrocarbon internal combustion engines since the familiar Otto-cycle internal- combustion engine was developed in the 19th century. Tests in the 1990s showed that the rotary engine burns liquid hydrogen well. Hydrogen exhaust would be harmless, unlike the exhaust from petroleum-based fuel. Liquid hydrogen is difficult and expensive to produce and store, but if it ever becomes a common fuel, the Wankel engine could become much more practical.

Engine

Engine

Engine, machine for converting energy into motion or mechanical work. The energy is usually supplied in the form of a chemical fuel, such as oil or gasoline, steam, or electricity, and the mechanical work is most commonly delivered in the form of rotary motion of a shaft. Engines are usually classified according to the form of energy they utilize, as steam, compressed air, and gasoline; the type of motion of their principal parts, as reciprocating and rotary; the place where the exchange from chemical to heat energy takes place, as internal combustion and external combustion; the method by which the engine is cooled, as air-cooled or water-cooled; the position of the cylinders of the engine, as V, in-line, and radial; the number of strokes of the piston for a complete cycle, as two-stroke and four-stroke; the type of cycle, as Otto (in ordinary gasoline engines) and diesel; and the use for which the engine is intended, as automobile and airplane engines. Engines are often called motors, although the term motor is sometimes restricted to engines that transform electrical energy into mechanical energy (see Electric Motors and Generators). Other specialized engines are the windmill, gas turbine, steam turbine, and rocket and jet engines.

Automobile engines get their power from burning fuel such as gasoline, diesel, or alcohol. The combustion, electrical, lubricating, and cooling systems need to work together to make the engine run smoothly and deliver power efficiently to the vehicle. The basic functions and interactions of these engine systems are shown in this series of slides. Many modern engines have a fuel injection system instead of a carburetor.

The combustion system turns fuel into the power that propels the car. In this diagram, the fuel injector sprays fuel into the intake manifold, where it mixes with air on its way into the cylinders. Inside the cylinders, the fuel-air mixture is compressed by the pistons as they pump upward. Spark plugs ignite the compressed fuel in a small explosion, which drives the pistons downward. Each piston connects to the crankshaft and as the pistons move up and down, the crankshaft turns. The crankshaft transfers this power to the transmission, which ultimately turns the axles and wheels.

The lubricating system reduces the friction produced by the engine’s moving parts, which may rub against each other thousands of times per minute. The main lubricant in an automobile engine is motor oil, which is held in an oil pan underneath the engine. A pump circulates the oil through tubes called galleries to all the moving parts of the engine. Before the oil circulates to the engine, it passes through an oil filter, which strains particles from the oil.

The electrical system manages the engine and provides the electricity necessary to keep the engine running. A key turning in the ignition allows electricity to flow from the battery to the starter. The starter includes a small motor that turns the crankshaft and sets the pistons in motion. As the crankshaft turns, it provides power to the alternator, which converts the turning power to electricity. This electricity ignites the spark plugs, recharges the battery, and operates the car’s lights, radio, and other electrical features. Most new cars also use small computers called electronic control units to monitor and regulate many of the car’s functions.

The cooling system draws heat away from the engine block, which would otherwise warp at the temperatures generated by combustion and friction. The water pump circulates engine coolant, a mixture of water and antifreeze, through the non-moving parts of the engine to absorb heat. The coolant routes through tubes in the radiator, where heat passes through the tubes into thin metal fins. A fan blows through the fins to increase the rate of cooling.