The air filter is the first protection of the engine intake system,which is divided into**main filter element(inner core+outer core)**,also known as safety inner core or safety filter element.The engine requires a large amount of air to do work.The air filter filters out dust,sand,and willow catkins in the air,supplying clean air to the turbocharger and cylinder combustion chamber to prevent hard particles from entering the cylinder and causing wear on the piston,cylinder liner,and valves.　　The external air first passes through an external filter to filter out most of the large particles...