Oil separator for internal combustion engine

Claim 1

In an internal combustion engine including a crankcase ventilation system, an oil separator casing formed integrally with the cylinder-head over, a partition defining the lower end of the oil separator, a baffle member for intercepting oil drops contained in blow-by gas flowing into the oil separator from the upper chamber of the cylinder, and an outlet port formed in the wall of said oil separator casing to exhaust gas from the oil separator, wherein the improvement comprises: said baffle member being arranged at the open lower end of the oil separator, a filter member made of foam metal and arranged so as to divide the inside of the oil separator into a gas-liquid separating chamber in the upperstream side where said baffle member is arranged and a downstream side chamber where said partition is arranged, said filter member functioning so as to absorb oil constituents contained in blow-by gas passing through said baffle member, a relief valve being arranged in said partition so as to be opened when the internal pressure of said upper chamber of the cylinder increases to a predetermined degree, to introduce the blow-by gas into said downstream-side chamber directly from said upper chamber of the cylinder.