Crankshaft function in engine

The crankshaft is an engine component that functions to convert the piston's reciprocating motion (the up and down movement of the piston) into a rotary motion that can rotate the flywheel. Simply put, the crankshaft function is converting a linear motion to a rotational motion.

The rotational motion that occurs in the crankshaft will be forwarded to the transmission and then to the wheels so that the car can move forward or backwards.

The crankshaft is located inside the car engine just below the engine cylinder attached to the cylinder block. A crankshaft is generally made of cast iron that has been strengthened to withstand large and fast loads and moments when the engine is rotating at high speeds and loads.

A crankshaft requires additional crankpins (rod journal) and bearings attached to the piston connecting rod on each cylinder to change the pistons up and down motion. On the other side, the main bearings are attached to the crankshaft main journal to ensure the crankshaft rotates in a smooth rotation inside the cylinder block. Look at the crankshaft's picture and its parts below.

Following are the parts of the crankshaft and their functions

Crank Pin / Rod bearings journal: is part of the crankshaft associated with the connecting rod and piston. In this crankpin, a rod bearing is generally installed. Inside the crankpin, an oil hole functions to lubricate the friction area between the crankpin and the connecting rod bearings.
Main Bearings Journal: is a part of the crankshaft associated with the engine cylinder block. In the main bearings journal, the main bearing is usually installed. In this main bearings journal, there is also an oil hole that functions to lubricate the main bearing.
Counterweight / Balancer Weight: is part of the crankshaft, which functions as a counterweight when the crankshaft rotates. In this counterweight, there are holes made to adjust the weight of each counterweight to balance the overall crankshaft rotation.
Oil Hole/ Oil passageways: is the hole where the engine oil flows throughout the crankshaft. This oil hole is generally connected between the crank journal and the crank pin.
Crank arm: is the part of the crankshaft that connects the crank journal to the crank pin.