TWO-VALVE ENGINE

摘要

The present invention provides a two-valve engine in which fuel economy can be improved while also suppressing combustion noise. This two-valve engine includes: a crankshaft; a rolling bearing; a piston part; a cylinder part including a cylinder head that has one intake port and discharge port, and a cylinder body that has a cylinder bore, said cylinder part forming a combustion chamber together with the piston part; a fuel injection part; and an ignition part provided to one area among two areas defined by dividing the combustion chamber using a straight line passing through the center of the intake port and the center of the discharge port. The piston part has a recess in a top face thereof. The surface area where the recess overlaps with an area where the ignition part is not provided is smaller than the surface area where the recess overlaps with an area where the ignition part is provided. An intake passage is provided such that an area in which the ignition part is not disposed and which has a small overlapping surface area with the recess is placed above a straight line that is an extension of the center axis of the intake passage from the center of the intake port.