Engine

A vertical, straight two-cylinder engine comprising:

• a cylinder head including combustion chamber roofs of the two adjacent cylinders,
• a branched intake port for introducing intake air into the adjacent cylinders,
• intake valve ports provided at branched ends of the intake port, an intake poppet valve provided in each intake valve port and intake air being sucked through the intake valve ports along a wall between the cylinders,
• one throttle body attached to the cylinder head,
• one fuel injector attached to the one throttle body, and
• a pair of crank pins having a crank pin angle set to 360 degrees,
• wherein:
• when viewed parallel to cylinder center axes, assuming a width direction of the cylinder head as a horizontal direction, a port inlet of the intake port is disposed just beside a partition wall for partitioning the combustion chamber roofs of the adjacent cylinders, port central axes of the intake port are disposed closer to the partition wall than a central virtual line of each cylinder, the central virtual line passing corresponding one of the cylinder center axes and extending horizontally,
• when viewed parallel to the cylinder center axes, the intake port comprises a pair of curved ports protrudingly curving in a direction away from the partition wall, extending from the port inlet and terminating atop the cylinders, and a corresponding pair of straight ports extending straight in a direction toward the centers of the combustion chamber roofs, from terminal ends of the curved ports to the intake valve ports at the combustion chamber roofs,
• when viewed parallel to the cylinder center axes, tangential virtual lines extending from endpoints of curved port central axes along tangent lines of the endpoints pass the intake valve ports, and straight port central axes extending from the endpoints of the curved port central axes are further away from the partition wall than the tangential virtual lines,
• such that the intake air bent through the curved ports passes the straight ports, and is sucked through the intake valve ports along the wall between the cylinders,
• wherein fuel injected from the one fuel injector hits directly against a valve head of each intake valve at the same time, and the fuel is injected from the fuel injector to the intake port within a crank angle range from preceding 40 degrees to subsequent 30 degrees of a bottom dead center, partitioning an explosion stroke and an exhaust stroke of one cylinder and partitioning an intake stroke and a compression stroke of another cylinder at the same time.