Two Cycle

—A type of internal combustion engine in which the four operations of charging, compre ion, explosion and expulsion are carried out during two strokes of the one piston. The piston usually serves as exhaust valve; the exploded charge escaping through por is in the cylinder wall, which are uncovered by the piston as it nears the extremity of its outward or power stroke. The incoming charge is either admitted by a separate valve or pump, or else pa es into the cylinder by ports opposite the exhaust port, the ire being deflected to the end of the cylinder by a ridge upon the piston, and scavenging out the products of combustion as it comes in. Compre ion ensues upon the closing of inlet and exhaust ports by the piston.