“Designing gasoline engines was not only a science, but an art.”  During the turn of the century, when trying to build the first motorcycle engine, horsepower output was incredibly low.  Pedals were left on the bikes so that when their engines/drive trains were insufficient, the driver could actually pedal the bike.  To fix this problem, the Otto Cycle engine was made.  It was a four-stroke engine that was sometimes called the “cycle.”  The four strokes were the intake stroke, the compression stroke, the power stroke, and the exhaust stroke.  During the intake stroke, the piston moves down from the top of the cylinder, creating an increase in volume.  During the compression stroke, the piston begins moving up, until it again reaches the top of the cylinder.  During the power stroke, the precise moment the piston is at the top of the stroke, fires, igniting the air-fuel mixture.  “This causes a catastrophic contained explosion.”  The burning air-fuel mixture expands and creates enormous pressure.  This drives the piston down to the bottom.  Then during the exhaust stroke, a valve opens and the piston starts coming up again.  This decreases the volume of the cylinder, forcing out the burned gases from combustion.

Visualize- Justin Gerade