The present invention relates to a breather arrangement associated with a cam case of an internal combustion engine and, more particularly, to a breather arrangement which ventilates a cam case and/or a crankcase while preventing blow-by gas from being emitted from the cam case and/or the crankcase to the atmosphere.
In the automotive internal combustion engine, blow-by gas produced in a cam case and a crankcase is recirculated to an intake system so that it may be burned in combustion chambers and not be emitted to the atmosphere. The recirculation is usually implemented by a conduitwork which draws out blow-by gas produced in the crankcase by way of the cam case or draws it out directly from both the crankcase and the cam case. The prerequisite with such a conduitwork is that the blow-by gas be prevented from entraining engine oil out of the crankcase and cam case and causing it to be wastefully burned in the combustion chambers. This prerequisite has heretofore been fulfilled by arranging an oil separator at the or each blow-by gas outlet for separating engine oil from blow-by gas.
Oil separators proposed in the past include a breather chamber which is furnished with several baffle plates, as disclosed in Japanese Utility Model Publication Nos. 57-32247 and 57-50486, for example. The problems with the prior art breather chamber schemes are that when applied to a cam case the breather chamber has to be defined in an upper portion of the cam case, and that the breather chamber cannot attain sufficient oil separation ability unless provided with a considerable capacity. These directly translate into an increase in the overall height of the engine so that where such an engine is used to power an automotive vehicle, the hood line of the vehicle need be undesirably raised.