What does the term stroke refer to in engine terminology?

The term "stroke" in engine terminology specifically refers to the distance the piston travels from the top of its cylinder (top dead center) to the bottom of its cylinder (bottom dead center). This movement is critical because the stroke length plays a significant role in determining the engine's displacement and, consequently, its power output.

In essence, the stroke is a key measurement that influences how much air-fuel mixture can be drawn into the cylinder during the intake stroke and how much exhaust is expelled during the exhaust stroke. A longer stroke typically allows for a larger volume of combustion within the cylinder, which can enhance power generation.

Understanding stroke is essential for evaluating engine performance characteristics, such as torque and horsepower, and is crucial when designing engines for specific applications. This concept is foundational in engine mechanics, making it important for anyone studying small engines to grasp the significance of stroke length.