Patent ID: 9316145
Filing Date: 2016-04-19
CPC Classification: F02B,F02F,F02M

Claim Text:
1. A two-stroke engine comprising: a cylinder provided with an approximately cylindrical shape; and a piston that can reciprocate between a top dead center position and a bottom dead center position in the cylinder, the cylinder including: the piston has a top surface, part of the top surface being concave and comprising a piston concave portion; an entire surface of the piston concave portion having an approximately spherical shape; and a slope of the piston concave portion extending from an outer circumferential edge of the piston concave portion in the discharge direction, to a deepest portion, is steeper than a slope of the piston concave portion extending from an outer circumferential edge of the piston concave portion, in the anti-discharge direction, to the deepest portion; the piston concave portion has a width dimension extending in the discharge direction and in the anti-discharge direction and orthogonal to a bore center line of the cylinder, and a half or larger portion of the width dimension is on the exhaust port side with respect to the bore center line.