| 摘要 |
PURPOSE:To reduce knocking noise of the piston in such a way that in the outer periphery of a piston in an internal combustion engine, part on the anti-thrust side which contacts the wall face of a cylinder when it is in compression stroke at least is notched slantwise as it comes near to its axial line toward the upper part of the piston. CONSTITUTION:A piston (a) is conically formed from the skirt part (a2) of the lower part toward a ring land part (a1), and an exhaust port 2 and an air inlet port 3 are opened toward the inner wall face in a cylinder b. In the piston (a), part on its anti-thrust side S2 is notched slantwise as it comes near to its axial line l2 toward the upper part of the piston. This notched part (a2) is faced opposite to the exhaust port 2 at the time of top dead point, and formed over the length extent between its upper side and lower side. In consequence, the angle alpha to the axial line l2 of the cylinder for the piston becomes larger, and when it is transferred to expansion stroke, it clashes from the lowest part of the skirt part (a2) which is thin and less rigid to the cylinder wall face, and knocking noise is reduced. |
