What is the primary function of a crankshaft in a vehicle?

The primary function of a crankshaft in a vehicle is to convert the linear motion of the pistons into rotational motion. In an internal combustion engine, the pistons move up and down in response to the combustion process. As they do so, they are connected to the crankshaft via connecting rods. The crankshaft is designed with offset journals, allowing it to turn as the pistons move linearly. This conversion process is essential because the rotational motion produced by the crankshaft is what ultimately drives the vehicle's wheels through the transmission system.

Understanding this mechanism is crucial, as it is the basis of how internal combustion engines function. The crankshaft's design and placement in the engine enable efficient transfer of energy, which is necessary for the vehicle to operate. The other functions noted in the options are not the primary responsibilities of the crankshaft, making it clear why the conversion of linear motion to rotational motion is its key role.