A crankshaft contains several parts that work in tandem to make a vehicle move. It has crankpins and cranks connected to connecting rods and vibration dampers that help mitigate crank thrusts. Below is a detailed description of how the crankshaft works in a 4-stroke engine.
Downward Motion of Piston
In the first step, the engine piston moves from the top dead center to the bottom dead center in a downward motion. During this movement, the piston connected to the crankshaft through a connecting rod transfers its motion to it.
Motion Transformation
The next step involves transforming the piston's linear motion into a rotary motion by the crankshaft. Furthermore, the crankshaft transfers this rotary motion to the camshaft after this transformation.
Compression
The camshaft receiving the rotary motion from the crankshaft facilitates the opening of the inlet valve. As a result, it allows the entry of air-fuel mixture into the engine combustion chamber. With the combustion chamber full, the piston moves from the bottom dead center to the top dead center in an upward motion, compressing the air-fuel mixture.
Also, as the piston moves upwards, the camshaft closes the exhaust and inlet values, completing the compression process. It also completes the first revolution of the crankshaft.
Ignition
The Ignition phase is the next phase after the completion of compression. The heat released at the onset of the ignition phase pressures the piston into a downward stroke, also known as a power stroke. As this downward motion progresses, the piston also transfers its linear motion to the connecting rod affixed to the crankshaft.
Flywheel Motion
The crank has two ends, with one end connected to the flywheel. Hence, as the crank receives the linear motion of the piston, it converts it into a rotary motion. Subsequently, the crank transfers this rotary motion to the flywheel, which stores the motion to facilitate vehicular wheel movement.
Exhaust Stroke
This stage ends in the discharge of exhaust gasses from the combustion chamber due to the piston's downward motion. Here, the camshaft receives the downward motion of the piston, consequently opening the exhaust valve.
