Patent ID: 8439005

Claim:
A two cycle engine comprising: an exhaust port provided in a side portion of a cylinder; and at least a pair of scavenge air ports provided in the side portion of the cylinder so as to be symmetrical with respect to a plane including an axis of the cylinder and a center line in a cylinder circumference direction of the exhaust port, wherein each scavenge air port is so oriented that, as viewed in a cylinder axis direction, an axis extending to inside of the cylinder from an opening of the scavenge air port extends in such a direction as to be away from the exhaust port of the cylinder, and the scavenge air port is divided in the cylinder axis direction, wherein in a cross-section taken by cutting the dividing portion along a plane including the axis of the cylinder and the center line in the cylinder circumference direction of the scavenge air port, a prolongation prolonged from a top-dead-center-side wall of the scavenge air port of a top-dead-center side is angled toward the top-dead-center side with respect to a line that is vertical to the axis of the cylinder, and a first angle formed by a first line and a second line is larger than a second angle formed by the second line and a third line, and wherein the first line is formed by the prolongation from the top-dead-center-side wall of the scavenge air port of the top-dead-center side, the second line is vertical to the cylinder axis, and the third line is formed by a prolongation into the cylinder from a top-dead-center-side wall of the scavenge air port of a bottom-dead-center side.