Patent ID: 6352058
Filing Date: 2002-03-05
Classification: F02B,F02M

Abstract:
An air scavenging two-stroke cycle engine that introduces fuel-air mixture introduced into a crank case provided on a lower portion of a cylinder into a combustion chamber in an upper portion of the cylinder from a first scavenging port and discharges a combustion gas externally from an exhaust port, by up and down movement of a piston in the cylinder, comprising:an intake port through which the fuel-air mixture is introduced into the crank case; a second scavenging port formed in the cylinder such that the second scavenging port is positioned above the intake port and opposite to the exhaust port in a diameter direction of the cylinder and has an upper end higher than an upper end of the first scavenging port; an air passage that communicates with the second scavenging port, for taking; only air externally of the engine; a check valve provided in the air passage to permit flow of the taken-in air toward the second scavenging port; and a communicating passage that makes a portion of the air passage that is situated downstream of the check valve and close to the second scavenging port and the crank case communicate with each other and has a main part comprising a connecting pipe placed externally of the engine.