In engine terminology, a cycle is defined as which of the following?

• A. An operation or series of events that repeats itself
• B. A single piston movement
• C. A fixed sequence that never repeats
• D. A continuous acceleration event

Answer: (A)

In engine terminology, a cycle is a repeating sequence of events that returns to the starting point and then starts again. The cycle describes the complete set of steps the engine goes through in order, and these steps repeat with each repetition of the process. For example, in a typical internal combustion engine, the cycle includes intake, compression, power (firing), and exhaust, and after exhaust the sequence begins anew with the next intake. A single piston movement is just a stroke, not a cycle. A fixed sequence that never repeats isn’t a cycle, and a continuous acceleration event isn’t how cycles are defined. That repeating series of steps is what makes up a cycle.