Lubricating oil is a liquid or semi-solid lubricant used in various types of automobiles and mechanical equipment to reduce friction and protect machinery and processed parts. It mainly plays a role of lubrication, auxiliary cooling, rust prevention, cleaning, sealing and buffering (Roab) .
As long as it is applied between two relatively moving objects, it can reduce the friction and abrasion of the two objects due to contact, that is, lubricating oil.