The crankshaft is essentially the backbone of the internal combustion engine. The crankshaft is responsible for the proper operation of the engine and converting a linear motion to a rotational motion.
The crankshaft is the engine component that converts the vertical movement of the pistons into the rotational movement required to move a vehicle. The energy of the rotating crankshaft is passed through the flywheel and transmission system, then through the driveshaft (on rear-wheel drive vehicles) or transaxle (on front-wheel drive vehicles), and on to the drive wheels that move the car.
The crankshaft is a heavy-duty piece of kit, usually made of steel or iron, that sits at the bottom of the engine. It is coupled to the base of the pistons via connecting rods that attach to crank pins at points that are offset, in a zig-zag shape, from the crankshaft’s centreline. This set-up is what enables the vertical movement of the pistons to spin the crankshaft and create rotational energy.
While the crankshaft is responsible for creating this spinning energy, it does perform other tasks. On the crankshaft end opposite the flywheel is a pulley to which the drive belt is attached. This drive belt feeds off the movement of the crankshaft and powers various components located at the front of the engine, including the alternator (which provides electric power when the vehicle is moving), the air conditioning compressor, and power steering pump, amongst other items.
The crankshaft’s movement is also directly linked to the input of fuel and air into the cylinders via its connection to the camshaft via the timing belt. The synchronization of the movement of the crankshaft and camshaft is critical to an engine’s performance.