As well known to those skilled in the art, while an engine is running, combustion gas and unburned gas, which are generated in the explosion stroke of the engine, leak into a crankcase through a fine gap between a piston and a cylinder liner. This gas is called “blow-by gas”.
The blow-by gas, which is drawn into the crankcase, is guided to a cylinder head cover, which is disposed on top of the cylinder head of the engine. The blow-by gas, which is guided to the cylinder head cover, is then guided to an intake system of the engine and is thus re-burnt.
However, during this process, oil mixes with the blow-by gas. As the amount of oil that mixes with the blow-by gas is increased, the consumption rate of oil in the engine increases, the durability of the engine is deteriorated, and the amount of harmful exhaust gas is increased. As such, many problems are caused.
To solve the above-mentioned problems, an oil separating apparatus, which is provided on the path in the cylinder head along which the blow-by gas travels, was proposed.