Patent attributes
An oil separator disposed inside a cylinder head cover of an internal combustion engine. The oil separator includes a body section defining an elongate separator chamber and having a blowby gas inlet and a blowby gas outlet. A partition wall is disposed to divide the separator chamber into an inlet chamber at side of the blowby gas inlet and an outlet chamber at side of the blowby gas outlet. The partition wall is formed with a plurality of passage holes each of which is triangular in cross-section. A collision plate is disposed inside the outlet chamber and located opposite to the passage holes of the partition wall. A slit-like opening is defined by a lower section of the collision plate and communicated with a drain section for discharging oil separated from blowby gas into a valve operating chamber.