INTRODUCTION WORKING PRINCIPLE MATERIAL FUEL CONSUMPTION & EMISSION ADVANTAGES DISADVANTAGES APPLICATION CONCLUSION The rotary engine was an early type of internal combustion aircraft engine, used mostly in the years shortly before and during World War I. It is also used in a few motorcycles and cars. In concept, a rotary engine is simple. It is a standard Otto cycle engine, but instead of having an orthodox fixed cylinder block with rotating crankshaft the crankshaft remains stationary and the entire cylinder block rotates around it. Among most of the rotary engine the most notable is the pistonless rotary engine ,the wankel engine. The Wankel rotary engine is a type of internal combustion engine, invented by German engineer Felix Wankel, which uses a rotor instead of reciprocating pistons. This design delivers smooth high-rpm power from a compact, lightweight engine. Rotor Wankel engine, a single oval (technically a epitrochoid) housing surrounds a three-sided rotor (a Reuleaux triangle) which turns and moves within the housing. The shaft turns 3 times for each rotation of the rotor around the lobe and once for each orbital revolution around the eccentric shaft. The Wankel engine works on a typical Otto cycle Wankel rotor housings are constantly heated on one side and cooled on the other, leading to high local temperatures and unequal thermal expansion. Therefore material used are exotic alloys and ceramics. The shape of the Wankel combustion chamber prevents preignition, it also leads to incomplete combustion of the air-fuel charge, with the remaining unburned hydrocarbons released into the exhaust. Fuel consumption is high. Have higher output for similar displacement and physical size. It is simple and have fewer moving parts. No need for connecting rods, a conventional crankshaft, crankshaft balance weights, etc. Smoother flow of power but also the ability to produce more power by running at higher rpm. fuel of very low octane number can be used without preignition or knock. It’s substantial safety benefit makes it useful in aircraft. Time available for fuel to be injected into a Wankel engine is significantly shorter . More complicated fuel injection technologies are required . In terms of fuel economy, Wankel engines are generally less efficient than four stroke piston engines . Sealing loss is high. the compression ratio is lower. This lowers the thermal efficiency and thus the fuel economy. It is difficult to expand the engine to more than two roters. Used in aircraft. Racing car. For mini, micro, and micro-mini engine designs. The most exotic use of the Wankel design is in the seat belt pre-tensioner system of some Mercedes-Benz.