Farm Power & Machinery

First stroke (Suction and Compression)

 
• When the piston moves up in the cylinder it covers two of the ports, the exhaust port and transfer port, which are normally almost opposite to each other. This traps a charge of fresh mixture in the cylinder and further upward movement of the piston compresses this charge. Further movement of the piston also uncovers a third port in the cylinder called transfer port and the charge is compressed. More fresh mixture is drawn through this port into the crankcase. Just before the end of this stroke, the mixture in the cylinder is ignited in the two stroke cycle. The first stroke is depicted in Plate 3.2.
  
  Plate : 3.2 First stroke in two stroke engine