What component turns the crankshaft in an engine?

The component that turns the crankshaft in an engine is the piston and connecting rod. When fuel and air are ignited in the combustion chamber, the resulting explosion pushes the piston down the cylinder. This linear motion of the piston is transmitted to the crankshaft through the connecting rod, which converts the up-and-down movement of the piston into the rotational motion needed to turn the crankshaft. This rotation ultimately drives the engine’s output, whether that’s propelling a vehicle or powering machinery.

The flywheel, while essential in maintaining momentum and stabilizing the engine's rotation, does not directly cause the crankshaft to turn. The camshaft is responsible for opening and closing the engine's valves to control the intake and exhaust of gases, which is a different function from that of the crankshaft. Similarly, valves are vital for directing airflow into and out of the engine but play no role in the direct motion of the crankshaft itself. Understanding the specific roles of these components helps clarify how an engine operates as a whole.