Crankcase is an important part of automobile engine. If the crankcase is not ventilated, the pressure in the crankcase will be too high, which will further affect the piston descent and the sealing performance of the crankcase. So the crankcase should be ventilated. In order to solve this problem, engineers specially developed a set of crankcase forced ventilation system to ventilate the crankcase. During the power stroke, part of the high-pressure gas in the combustion chamber will enter the crankcase through the piston ring. The exhaust gas in the crankcase will pollute the air if it is directly exposed to the atmosphere. Therefore, the engine is equipped with a special crankcase ventilation system. Under the action of the system, the exhaust gas in the crankcase can be introduced into the intake manifold and then participate in combustion. However, there is another important component in the crankcase ventilation system, namely the oil-gas separator. Its function is to separate oil and gas and prevent oil and gas from entering the combustion chamber, causing serious carbon deposition in the engine and affecting the engine oil combustion. Therefore, the oil-gas separator plays a vital role in the forced ventilation system of engine crankcase.