As we all know, a piston engine is a reciprocating engine, it has to moved up and down to produce power. The basic component used in a piston engine is the piston itself, valves, camshaft, crankshaft and the spark plug. It need four types of event (called stroke) to produce one complete cycle. http://kereta.info/video-struktur-enjin-kereta-dan-bagaimana-ia-berfungsi/
But for a rotary wankel engine, which is use in the Mazda RX3, RX7 and RX8, it is a different story.First of all a rotary engine doent use a piston. Even the camshaft is not needed for a rotary engine.A rotary engine mainly consist of rotor housing, rotor, eccentric shaft, intake port, exhaust port and a spark plug
By using a rotary engine, fe advantage can be gained, first, the rotary wankel doesnt reciprocate, which mean there is a lot less vibration compared to a piston engine. Second, the rotary engine gives high power to capacity ratio and also high power to weight ratio.A 1.3l RX7 engine can produce 280bhp easily with the help of a turbocharger. But the main draw back is the fuel consumption Even if it is a 1.3L engine,the fuel consumption is very high and comparable to a 3liter engine.
The basic working principle of the engine is simillar to a piston engine, there is an intake stroke, compression stroke, combustion stroke and exhaust stroke.But the rotor moves in a rotation rather tha reciprocate like the piston.
Refer to this video to get a better idea on how rotary wankel engine works.
[youtube:http://www.youtube.com/watch?v=rr4mn9di5WU 425 344]