What do the four strokes of a four-stroke engine refer to in sequence?

The four strokes of a four-stroke engine are sequentially referred to as intake, compression, power, and exhaust.

This sequence begins with the intake stroke, during which the engine draws an air-fuel mixture into the combustion chamber as the piston moves down. Following this is the compression stroke, where the piston moves back up, compressing the fuel-air mixture, which increases its potential energy and prepares it for combustion.

The third stroke is the power stroke. During this stage, the compressed mixture is ignited, typically by a spark plug in gasoline engines, leading to a rapid expansion of gases that pushes the piston down, generating power. Finally, the exhaust stroke occurs, where the piston moves back up again to expel the burnt gases from the combustion chamber, completing the cycle and making the engine ready for the next intake stroke.

This clear sequence ensures the efficient operation of the engine, allowing for the conversion of fuel into mechanical energy. The understanding of these strokes is fundamental for anyone working with or studying engines, particularly in contexts like forklift operation and maintenance.