Patent ID: 8511291

Claim:
A positive crankcase ventilation system provided in an internal combustion engine, comprising: an air introduction passage through which new air present in an inner space of a cylinder head is introduced into a crankcase from the inner space of the cylinder head; a blow-by gas collection passage through which a first breather chamber provided in an upper portion of a cylinder is connected to an inside of the crankcase, wherein: blow-by gas in the crankcase is delivered to an intake system through the blow-by gas collection passage and the first breather chamber; the blow-by gas collection passage is formed by a partition that separates the blow-by gas collection passage from the inner space of the cylinder head; and a connection portion, through which the inner space of the cylinder head is connected to the blow-by gas collection passage, is provided in the partition wall, wherein: the first breather chamber formed by a breather case attached to a head cover provided on the cylinder head; and the connection portion is defined by an upper surface of an upper end portion of the partition wall and a lower surface of the breather case.