What is the main function of an air filter?

Everyone knows that air filters can handle high-efficiency air filtration and can work continuously for a long time. But do you know the main function of an air filter? Let's find out together.

During operation, the engine takes in a large amount of air. If the air is not filtered, the suspended dust in the air will be sucked into the cylinder, accelerating the wear and tear of the piston assembly and cylinder. Larger particles entering between the piston and cylinder will cause serious "scoring," which is particularly serious in dry, sandy work environments. The air filter is installed in front of the carburetor or intake pipe to filter out dust and sand in the air, ensuring that the cylinder receives a sufficient amount of clean air.

Among the countless parts of a car, the air filter is an extremely inconspicuous component because it doesn't directly affect the car's technical performance. However, in actual use, the air filter has a significant impact on the service life of the car (especially the engine). On the one hand, without the filtration of the air filter, the engine will inhale a large amount of air containing dust and particles, leading to serious wear and tear of the engine cylinder. On the other hand, if it is not maintained for a long time during use, the air filter element will become clogged with dust, which not only reduces the filtration capacity but also hinders air circulation, leading to an overly rich air-fuel mixture and abnormal engine operation. Therefore, regular maintenance of the air filter is crucial.

Air filters generally come in paper and oil-bath types. Because paper filters have advantages such as high filtration efficiency, light weight, low cost, and easy maintenance, they have been widely adopted. The filtration efficiency of paper filter elements is as high as 99.5% or more, while the filtration efficiency of oil-bath filters is 95-96% under normal conditions. The air filters widely used in cars are paper filters, which are further divided into dry and wet types. For dry filter elements, once they are immersed in oil or water, the filtration resistance will increase sharply. Therefore, avoid contact with water or oil during cleaning; otherwise, the filter element must be replaced.

When the engine is running, the intake is intermittent, causing air vibration inside the air filter housing. If the air pressure fluctuation is too large, it may sometimes affect the engine's intake. In addition, this will also increase intake noise. To suppress intake noise, the volume of the air filter housing can be increased, and some also have baffles to reduce resonance.

Air filter elements are divided into dry and wet types. Dry filter elements are made of filter paper or non-woven fabric. To increase the air passage area, most filter elements are processed with many small pleats. When the filter element is slightly soiled, compressed air can be used to clean it. When the filter element is severely soiled, it should be replaced.

Wet filter elements are made of sponge-like polyurethane materials. When installing, add some engine oil and rub it evenly by hand to absorb foreign matter in the air. If the filter element is soiled, it can be cleaned with cleaning oil. If it is excessively soiled, the filter element should be replaced.

That's the summary. However, I want to remind everyone that if the filter element is severely blocked, the engine power will decrease. Therefore, we should develop the habit of regularly checking the air filter.