In a diesel engine, the purpose of the crankshaft is to convert the reciprocating motion of the pistons into rotational motion. When engine is running, the pistons move up and down within their respective cylinders. The crankshaft is connected to the pistons by means of connecting rods. As the pistons move, they push and pull on the connecting rods, which in turn cause the crankshaft to rotate. The crankshaft's rotational motion is then used to power the engine's various components, such as the transmission, oil pump, and water pump.
In general, the crankshaft in a diesel engine is a crucial component that facilitates the conversion of heat energy generated during the combustion process into useful mechanical work.