| 摘要 |
PURPOSE:To carry out satisfactory lubrication for the sliding section between a cylinder and a piston skirt part over the entire periphery thereof in a two-cycle internal-combustion engine of crank chamber compressing and scavenging type, by introducing a mixture to the sliding section between the cylinder and the piston skirt part from the crank chamber. CONSTITUTION:Three scavenging ports 50 and an exhaust port 52 are opened to a cylinder sleeve 36 on the internal surface of each cylinder 30, the scavenging ports 50 being communicated with a crank chamber 42 through a scavenging passage 54 formed in the cylinder 30, and the exhaust port 52 being communicated with an exhaust passage 56. The cylinder sleeve 36 is formed with several grooves 60 extending to, at the upper end thereof, the lower side of the scavenging and exhaust ports 50, 52, and reaching, at the lower end thereof, the inclined surface 62 of the lower edge inner side. With this arrangement, upon inward stroke operation a mixture having flowed into the crank chamber 42 enters in between the piston 38 and the sleeve 35, thereby the lubrication is enhanced. |
