What is the primary purpose of the crankshaft in an engine?

The primary purpose of the crankshaft in an engine is to convert the linear motion of the pistons into rotational motion. As the pistons move up and down within the cylinders due to the combustion process, the crankshaft is linked to the piston rods. This connection allows the linear movement of the pistons to rotate the crankshaft, which ultimately drives the vehicle's transmission and wheels.

This conversion is essential for the engine's functionality, as it enables the kinetic energy generated from fuel combustion to translate into the mechanical energy needed to propel the vehicle. The design of the crankshaft, including its counterweights, also helps balance the engine and reduce vibrations during operation, ensuring smoother performance.

The other options refer to components or functions that are not directly related to the primary function of the crankshaft, as they deal with aspects like fuel delivery, timing in the combustion cycle, or managing heat, which are governed by different engine parts and systems.