Four Stroke Cycle

Four Stroke Cycle Or Otto Cycle, the operating cycle of most petrol and diesel engines, based upon the strokes or up and down movements of the pistons. It was first Exploited in 1876 by the German engineer Nicolaus August Otto. In the four stroke petrol engine cycle, petrol air mixture is drawn into an engine cylinder on the first stroke (down) of the piston. On the second stroke (up) the mixture is ignited by a spark. The mixture burns and produces gases that drive the piston down on its third, or power stroke. As the piston moves up on its fourth, exhaust stroke, it expels burnt gases from the cylinder.