In addition to the pump capacity of the oil pump, factors such as the oil passage area and the viscosity of the oil will affect the engine oil seal.When the engine is working, the normal oil pressure must be maintained. If the oil pressure is too low, the friction surfaces will wear faster due to insufficient lubrication; if the oil pressure is too high, it is easy to damage the oil seal and oil pipe and consume the engine power. When the engine is working, part of the oil is supplied to the turbocharger rotor bearing for lubrication and cooling. After the running engine stops suddenly, the oil pressure drops rapidly to zero. When the high temperature of the turbocharger turbine part is transmitted to the middle car for driving, the pressure of the lubricating oil is generally kept at about 0.4MPa. When the engine is idling, the oil pressure shall not be less than 0.1MPa. When the internal combustion engine is working, more than 70% of the fuel energy will be lost due to the associated effect. As a dynamic seal, the function of oil seal is to seal the lubricating oil of engine and prevent foreign matters from entering the engine. The crankshaft does not move around a concentric circle very stably in the operation process, but there is swing. The two changeable fulcrum points of the oil seal can effectively reduce the impact of swing of the rotating shaft on the sealing performance of the oil seal. The crankshaft of large engine has a large size, so when disassembling the supercharger, it should be kept clean, and each pipe joint must be blocked with a clean cloth to prevent The quality of damaged rotor, including the surface of parts and components, and the value of crankshaft swing will be more complex than that of gasoline engine. The oil seal can be adapted to the harsh use environment of heavy engine by corresponding adjustment of design and integration of a set of auxiliary dust lip.