Wankelmotor Engine how works function funktioniert rotary engine

How does a Wankel engine work

How does a Wankel engine work?

The Wankel engine is an internal combustion engine in which one or more triangular-shaped circular pistons convert the pressure generated during combustion of the fuel-air mixture into kinetic energy. The gas volumes transported in the spaces between the rotor flanks and the housing pass alternately through four different phases: a) intake phase; b) compression phase; c) expansion phase; and d) exhaust phase. These stages are referred to as strokes and make the Wankel engine a four-stroke engine, similar to the Otto reciprocating engine.


During this phase, a pressure drop caused by the movement of the rotor draws the fuel-air mixture into the cold chamber. The rotation of the rotor forces the mixture into the second stroke of the cycle.


As the piston continues to rotate, the volume enclosed between the rotor and housing decreases, compressing the fuel-air mixture.


When the mixture volume is minimal, one or more spark plugs initiate combustion, resulting in a rapid increase in pressure and temperature. The sudden expansion of the now gaseous fuel mixture further rotates the rotor and the eccentric.


The expanding exhaust gases leave the chamber through the exhaust port opened in the fourth cycle. As the piston continues to rotate, the exhaust port closes while the inlet port opens again to begin a new cycle.

Felix Wankel

History of Wankel engines

The Wankel engine (also known as the rotary piston engine or rotary piston engine) is an internal combustion engine invented in 1954 by German mechanical engineer Felix Heinrich Wankel as an alternative to the classic reciprocating piston engine.

After some technical improvements by engineer Hanns Dieter Paschke, the Wankel engine was first presented to experts and the press in 1960 at an event organized by the Association of German Engineers (VDI) in Munich.

In the 1960s, Wankel engines were the talk of the automotive and motorcycle industries due to their simplicity, smooth running and high power density. NSU Motorenwerke AG attracted a great deal of attention in August 1967 for its ultra-modern NSU Ro 80 passenger car, which was powered by a 115-hp Wankel engine with two pistons. It was the first German car to be named "Car of the Year" in 1968.

Over the next few decades, numerous major automakers signed licensing agreements to develop Wankel rotary piston engines, including Ford, Toyota, Mercedes-Benz, Porsche, Rolls-Royce and Mazda.

After further improvements to the engine, including solving the apex compression problem, Mazda successfully used rotary piston engines in its RX series sports cars until 2012. The technological edge of Wankel engines in the automotive industry was highlighted in the 1991 Le Mans 24 Hours race, when a car powered by the 4-rotor Mazda 26B engine won the prestigious competition.

Today, the continuously developed Wankel rotary piston engines are used in motorcycles, racing cars, aircraft, small ships and power generators. The next stage of development relates to the application of these drives in the coming era of low-emission, climate-neutral, reliable and affordable energy supply. The successful test of the hydrogen-powered Wankel engine on September 20, 2019, allows us to look to the future with confidence.

Hydrogen or synthetic diesel?

How can security of supply be guaranteed? Hydrogen or synthetic diesel? And what technologies already exist for sustainable energy supply?

This question was discussed over two days in Bonn. This September, we were invited by the Studiengesellschaft der Deutschen Gesellschaft für Wehrtechnik mbH to present our Wankel engines.

Why Wankel engines?

Wankel engines are able to convert hydrogen into controlled energy in addition to the fuel cell. (Without the use of rare earths).
In addition, our engines can run on synthetic fuels. A unique selling point of the engines manufactured by us is that they can run on diesel (and also synthetic diesel).

The current situation shows that security of supply, be it in industry but also in defense, is elementary. So we will continue to optimize our hydrogen engines and work on synthetic fuel operation.

For us, this is the future. Hydrogen AND synthetic fuels.

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