| 摘要 |
<p>Provided is a two-stroke engine capable of decreasing height in the vertical direction and reducing a blow-by by improving exhaust efficiency. This two-stroke engine comprises: a cylinder with a cylinder center axis extending in the horizontal or a nearly horizontal direction in a normal state of use, and with a columnar inner circumferential surface; a piston capable of reciprocating within the cylinder; and an exhaust channel portion provided in the cylinder. In the inner circumferential surface of the cylinder, an exhaust opening of the exhaust channel portion is formed, with most of the effective cross-sectional area of the exhaust opening being located at an upper-direction side position with respect to the center of the cylinder in a bore cross section in the normal state of use, the exhaust channel portion extending at an angle with respect to the radius direction in the bore cross section of the cylinder. In the inner circumferential surface of the cylinder, a cylinder-side scavenging opening of a scavenging channel portion is formed such that a scavenging flow scavenged via the cylinder-side scavenging opening is directed toward a lower-direction position with respect to the cylinder center axis in the bore cross section in the normal state of use.</p> |
