Which component transfers combustion energy to the crankshaft?

The piston is the component that transfers combustion energy to the crankshaft in an internal combustion engine. When the fuel-air mixture ignites within the cylinder, it creates pressure that forces the piston downward. This downward motion is the result of the expansion of gases from the combustion process.

As the piston moves down, it is connected to the crankshaft through the connecting rod. This connection allows the linear motion of the piston to be converted into rotational motion in the crankshaft, which is essential for propelling the engine and ultimately the vehicle.

In contrast, while the cylinder head plays a role in sealing the combustion chamber and the camshaft is involved in timing the opening and closing of the valves, they do not directly transfer energy to the crankshaft. The connecting rod, although it links the piston to the crankshaft, does not itself generate energy but merely facilitates the transfer of energy created by the piston's movement. Thus, the correct answer is the piston, as it is primarily responsible for harnessing the energy from combustion and initiating its transfer to the crankshaft.