There are many components that add up to make an internal combustion engine. These components include: a cylinder, a cylinder head, pistons and rods, a crankshaft. 

*The cylinder is one of the most important parts of the engine. This part guides and houses the piston, allowing it to move up and down freely.
 
http://www.automation-drive.com/engine-block

*The cylinder head is the next important part of the engine. It allows the air to mix with the fuel into the engine. Once the combustion happens, it opens again letting the exhaust out of the engine. Very precise timing with the use of synchronized valves opening and closing does this.

http://www.motorera.com/dictionary/cy.htm

*The pistons and rods are the moveable parts that go up and down in the cylinder of the engine. When they move up they compress the air fuel mixture in the engine, which is then ignited by the spark of the spark plug.

*The final main component is the crankshaft. The crankshaft is what is connected to the pistons. The crankshaft rotates and from this rotation, it moves the pistons up and down in the cylinder. Without all of these components the internal combustion engine would not work.

http://www.hensonracingengines.com/Crankshaft_Balancing.html

    Although the rotary engine is an internal combustion engine, it has different components then the other engines.  The main components of a rotary engine are the housing, the rotor, and the output shaft.

*The housing is somewhat self-explanatory to what it is. It is basically where everything is “housed” and where the air and fuel mix, combust, and ignites.

http://www.mr2.com/forums/threads/60417-Rotary-Engine

*The rotor is a triangular convex component that rotates around the housing.  Click Here to see how the rotor moves around the housing and how it contributes to the engines performance.


http://xtremerotaries.com/services/rotor-machining/lightening

*The final main component is the output shaft. It is also called the eccentric shaft due to the fact that it has round lobes that are mounted to it eccentrically. According to Howstuffworks.com “The lobe acts sort of like the crankshaft in a piston engine. As the rotor follows its path around the housing, it pushes on the lobes. Since the lobes are mounted eccentric to the output shaft, the force that the rotor applies to the lobes creates torque in the shaft, causing it to spin.”

http://auto.howstuffworks.com/rotary-engine2.htm