Which of the following is not a stroke in a 4-Stroke engine?

In a 4-stroke engine, there are four distinct strokes that take place in sequence: intake, compression, power (or combustion), and exhaust. The purpose of each stroke corresponds to different phases of the engine cycle.

The intake stroke draws in an air-fuel mixture into the cylinder. The compression stroke then compresses this mixture to prepare it for ignition. The power stroke follows, where the compressed air-fuel mixture is ignited, producing the power that drives the piston down. Finally, the exhaust stroke expels the burned gases from the combustion process out of the cylinder.

While ignition is a critical part of the engine's operation, it is not classified as one of the four strokes in the cycle. Instead, it occurs during the power stroke when the spark ignites the compressed mixture. Therefore, the correct answer is that ignition is not one of the four strokes in a 4-stroke engine.