What does Internal Combustion Engine do?
An internal combustion engine burns fuel inside a cylinder or other vessel. The classic example is a car engine where the exploding gases inside a cylinder push against a piston. The motion of the piston is converted by mechanical linkages into the movement of the wheels. An external combustion engine is something like a steam engine where the combustion boils water turning it into steam and it is this steam that drives the mechanism. The gases from the combustion do not directly drive the engine.
