The air filter is also called the air filter cartridge. It is mainly used for air filtration in engineering locomotives, automobiles, agricultural locomotives, laboratories, aseptic operating rooms and various precision operating rooms.

The engine takes in a large amount of air during its working process. If the air is not filtered and cleaned, the dust suspended in the air will be sucked into the cylinder, which will accelerate the wear of the piston group and cylinder. Larger particles enter between the piston and the cylinder, which will cause serious "squeeze the cylinder", which is especially serious in the dry and sandy working environment.

The air filter is installed in front of the carburetor or the intake pipe to filter out dust and sand particles in the air to ensure sufficient and clean air entering the cylinder.