| 摘要 |
PURPOSE:To produce two air streams consisting a swirl generating stream and an ignition plug scavenging stream by forming a pair of mutually spaced recessed parts which produce drift air stream passages at the time of generating drift, with a difference in head therebetween at either the end part downstream from a drift plate or an intake port. CONSTITUTION:When the r.p.m. or the load of an engine is low, a drift plate 16 stays in the position as shown in the drawing. Since a curved side part 16a which defines a drift air stream passage 20a extends along the side wall face 13c of an intake port 13 which is disposed in the position apart from the center of a cylinder, air turns about an intake valve 14 as shown by the line E. Since a recessed groove 18b which defines a drift air passage 20b extends along the side wall face 13d of the intake port 13 which is disposed at the side near the center of the cylinder, air flows toward an ignition plug 19 as shown by the line F, whereby the ignition plug 19 is scavenged by the effect of the intake air stream. |
