Have you ever wondered why the only kind of engine used is the 4-stroke internal combustion, if there are any other alternatives to it? There is a little known engine called the Wankel rotary engine. This engine is very unlike the regular 4-stroke internal combustion engine used in most cars; it uses no pistons.
"Felix Wankel conceived the idea of a rotary engine in 1924" (Marr) which re received a patent for in 1936. Since then the rotary engine has been developed by companies such as Mercedes-Benz, Chevrolet, Yamaha, Suzuki, Cessna, Artic Cat, Nissan and Mazda in the 1970s and 80s for motorcycles, cars, snowmobiles, airplanes, chainsaws, boats and even compressors and air conditioners. But only Mazda has continued to develop the engine and will include it in its upcoming sports car the RX-8.
Since it the rotary engine uses no pistons, the same volume of space (the cylinder) alternately does four different jobs: intake, compression, combustion, and exhaust. The pressure of combustion is contained in a "cylinder" formed by an apex of a triangular rotor (instead of pistons), and part of the housing. The rotor travels in a partially oval shape, keeping the apexes in contact with the housing, this forms three different volumes of gasses which alternately expand and contract, causing the suction required for to bring air and fuel in to the chamber.
The ignition and fuel delivery systems of a rotary engine are similar to a piston engine, but the other parts of a rotary engine are very different. The rotor [Figure A Rotor].
Figure A Rotor Figure B Housing.
(piston) has three convex surfaces with pockets in it, which allow more displacement, and therefore more air/fuel mixture. The apex seals are what keeps the combustion chambers separate, and are like the piston rings on a piston engine.
The housing [Figure B Housing] for the rotor is roughly oval, and is designed so all the apexes off the rotor are in contact with the housing wall.