Air filter is the equipment to filtrate the suspended particles. The archetype is the protective device that can protect the breath, its fast development related to military industry and electronic industry closely. During the World war I, because of the usage of the chemical poison, military antigas mask is born which requires the asbestos fiber as the smoke-filter.  In world war II, with the development of atomic energy industrial, it developed the air filter in order to remove the radioactive particles.

Air filter element

The element development group was built in year1942. It developed the filter material mixed with wood fiber, asbestos, cotton, its filtration efficiency reaches to 99.96%, which is the rudiment of the Hepa Filter now. Then it developed the mixed filter of glass fiber and is widely used in atomic energy technique. At that time, the filter material is fibrin, but this material has the problem of fire resistance and hygroscopicity. Now air filter is mostly use glass fiber.

 The performance of the air filter that used in the engine is firstly relates to the filter material, at the same time it relates to the structure of the filter itself as well as the quality of the element. The first requirement of the filter material is that its good air permeability to confirm the low flow resistance of the element. The second one is that the porosity appropriate to confirm the enough filtration efficiency and finess.

Engine air filter, the most widely used material is micropore filter paper that is processed by resin. The element pulp is processed by mercerization, the fiber is curly and soft, which makes the element multihole and loose. Besides the element is processed by resin, it not only enhance the mechanical strength of the element itself, but also it improves the antiwater of the paper element. So micropore paper element become the most reliable and widely used filter material for the engine.

Vehicle Air filter is the main part to confirm the air clean that comes to the engine cylinder, so it requires the filter material to have good air permeability , porosity appropriate, but these two points are contradictory. Usually it use different filter material to meet the different requirements of air filter. In order to confirm the filtration efficiency, no matter what material it use, the air filter element in the future will aim to be low consumption, low cost, large air inflow, high ability to store dust, good performance of water-resistance and high efficiency.