What is the key difference between 2-stroke and 4-stroke engines?

The key difference between 2-stroke and 4-stroke engines lies in the number of strokes required to complete one full cycle of power. In a 2-stroke engine, the power cycle is completed in just two strokes of the piston (one upward and one downward movement), meaning that power is produced with every revolution of the crankshaft. This allows for a more compact and lightweight engine design and can lead to increased power output relative to engine size.

In contrast, a 4-stroke engine requires four strokes of the piston (two upward and two downward movements) to complete a power cycle. This means that power is produced once every two revolutions of the crankshaft. The additional strokes in a 4-stroke engine include intake, compression, power, and exhaust, which results in more complete combustion and typically greater fuel efficiency, as well as reduced emissions.

The other options do not represent the fundamental operational difference between the two types of engines. Fuel types can vary across both engine categories, engine size can range within both designs, and the engine's cylinder count does not directly define the fundamental mechanics of the 2-stroke versus 4-stroke cycle. Thus, the understanding of power cycles is critical in differentiating between these two