The four-stroke cycle of an internal combustion engine is the cycle most commonly used for automotive and industrial purposes today, including cars, trucks, and generators.
The cycle was invented by Nikolaus Otto in 1876, and is also called the Otto cycle. The cycle is characterized by four strokes, or straight movements in a single direction, of the piston.Photo credit: Eric Pierce
 | This picture of the day has been featured on Portal:Technology. |