Plastic head cover of internal combustion engine

Abstract

A plastic head cover of an internal combustion engine having therein two parallel oil mist separator chambers comprises a plastic cover body that is adapted to be mounted on a cylinder head of the engine and includes lower portions of the separator chambers, and a plastic upper body that includes upper portions of the separator chambers and is mounted on and secured to the plastic cover body in such a manner that the upper portions possessed by the plastic upper body are mated with the lower portions possessed by the cover body, thereby forming an entire construction of the two oil mist separator chambers.

What is claimed is: 
     
         1 . A plastic head cover of an internal combustion engine, the plastic head cover having therein an oil mist separator unit for separating an oil mist from a gas led thereinto, the plastic head cover comprising:
 a plastic cover body adapted to be mounted on a cylinder head of the engine, the cover body including a lower portion of the oil mist separator unit; and   a plastic upper body including an upper portion of the oil mist separator unit, the plastic upper body being mounted on and secured to the plastic cover body in such a manner that said upper portion possessed by the plastic upper body is mated with said lower portion possessed by the cover body, thereby forming an entire construction of the oil mist separator unit.   
     
     
         2 . A plastic head cover as claimed in  claim 1 , in which said lower portion of the oil mist separator unit is provided by a partition plate that is integral with the cover body. 
     
     
         3 . A plastic head cover as claimed in  claim 2 , in which the oil mist separator chamber unit comprises first and second oil mist separator chambers that extend parallelly along a longitudinal axis of an integral unit that consists of the plastic cover body and the plastic upper body, and in which a plurality of aligned plug bores are formed in an axially extending center zone of the integral unit between the first and second oil mist separator chambers. 
     
     
         4 . A plastic head cover as claimed in  claim 3 , in which each of the plug bores is formed at an axially middle portion thereof with an enlarged rounded part. 
     
     
         5 . A plastic head cover as claimed in  claim 4 , in which each plug bore extends in a direction perpendicular to an imaginary contact surface at which an upper flat surface of the cover body and a lower flat surface of the upper body contact to each other. 
     
     
         6 . A plastic head cover as claimed in  claim 5 , in which the cover body is integrally formed, at positions below the partition wall, with a plurality of reinforcing ribs, each reinforcing rib extending between laterally opposed side walls of the cover body. 
     
     
         7 . A plastic head cover as claimed in  claim 3 , in which the axially extending center zone of the integral unit is constructed to have a plurality of closed section structures for increasing the rigidity of the axially extending center zone. 
     
     
         8 . A plastic head cover as claimed in  claim 7 , in which each of the closed section structures comprises an enclosed rib that is possessed by the cover body and a counter-enclosed rib that is possessed by the upper body and bonded to the rib of the cover body. 
     
     
         9 . A plastic head cover as claimed in  claim 3 , further comprising:
 a bolt bore formed in the axially extending center zone of the integral unit;   a groove defined between the cover body and the upper body and exposed to the bolt bore; and   a drain passage defined between the cover body and the upper body and extending from said groove to the outside of the integral unit.   
     
     
         10 . A plastic head cover as claimed in  claim 3 , in which the integral unit is formed with an L-shaped opening that consists of a first portion defined between a part of the cover body and a part of the upper body and a second portion defined between another part of the cover body and another part of the upper body. 
     
     
         11 . A plastic head cover having therein first and second parallel oil mist separator chambers and adapted to be mounted on an internal combustion engine, the plastic head cover comprising:
 a plastic cover body adapted to be mounted on a cylinder head of the engine, the cover body including a partition plate that is formed with lower portions of the first and second oil mist separator chambers;   a plastic upper body including upper portions of the first and second oil mist separator chambers, the upper body being mounted on and secured to the cover body in such a manner that said upper portions possessed by the upper body are mated with said lower portions possessed by the partition plate of the cover body thereby forming an entire construction of the first and second oil mist separator chambers;   a plurality of aligned plug bores formed in an axially extending center zone of an integral unit between the first and second oil mist separator chambers, the integral unit consisting of the cover body and the upper body;   a plurality of closed section structures possessed by the axially extending center zone of the integral unit for increasing the rigidity of the axially extending center zone; and   an L-shaped opening that consists of a first portion defined between a part of the cover body and a part of the upper body and a second portion defined between another part of the cover body and another part of the upper body.