Which of the following describes a four-stroke engine?

A four-stroke engine operates through a cycle that includes four distinct phases: intake, compression, combustion, and exhaust.

During the intake stroke, the engine draws in a mixture of air and fuel through an open intake valve. Following this, the compression stroke occurs, where the piston rises and compresses the air-fuel mixture, raising its temperature and pressure.

Next, the combustion stroke takes place when the compressed mixture is ignited, leading to an explosion that forces the piston down, performing work on the crankshaft. Finally, in the exhaust stroke, the exhaust valve opens and the piston pushes the spent gases out of the combustion chamber.

The correct sequence of these phases is essential for the engine to function efficiently, and the described order aligns with how a four-stroke engine operates. Understanding this cycle is crucial for grasping the fundamentals of internal combustion engines.