While visually inspecting the crankshaft, you can find the rod bearings are nearly offset or eccentric. Here the offset of the shaft transforms the reciprocating motion (up and down) of the piston in the rotating motion of the crankshaft.
Most often the shaft is drilled with minute holes which feed the engine with the oil necessary for smooth operations. Sometimes, this mechanical part consists of counterweights which help in balancing the system and the weight of the connecting rod. It also ensures to balance the force while rotation of the moving parts.
Every engine is designed specifically and so is the crankshaft. Its design varies with the size and number of cylinders in the engine. Featuring an example, in a four-stroke engine, the crankshaft will have four crank throws. These throws connect the four pistons and are efficiently connected to the flywheel of the engine.
While driving the engine or during the combustion cycle the crank throw works as a lever arm, which pushes and pulls the piston. This considerably creates a successive rotational motion in the engine.
The crankshaft helps the piston to complete its rotation and the throw will return the piston at the top of the cylinder. This product needs very sleek designing while production with respect to its weights and balancing. Such engineering is necessary to reduce the vibrations in the engine. Such, vibrations can be very harmful to the vehicle and can even lead to major accidents.