Lubrication: engine oil is the most important and most basic role.
For the parts of engine piston, bearings and to provide adequate lubrication.
Sealing effect: it fills the clearance between the cylinder and piston, in order to prevent the engine combustion chamber of high temperature and high pressure gas and gas leaking, so as to give full play to the power of the engine.
Cooling: in the process of running engine, a lot of heat generated in the friction between each part.
Besides by cooling system for heat dissipation, between the parts flow of oil through the oil sump or radiator to heat dissipation.
Anti-corrosion effect: when work, the oil production of lubricant film can be isolated from environmental medium such as air, steam and corrosive gas erosion of friction surface, prevent or slow rusting.
That, when burned, clean effect: smoke oil and insoluble components will affect the normal operation of the engine, and engine oil can effectively absorb the material.