Abstract
Traditional cellulose filter media used for air filtration in vehicle engines are characterized by 99.9% filtration efficiency and accuracy above 2-5 µm. The highest engine component wear is caused by dust grains above 1 µm. Filter media with nanofiber additions provide greater filtration efficiency of dust grains below 5 µm. Filter material selection for vehicle engine air filter is a problem because their manufacturers mainly provide only the structure parameters: pore size, air permeability, and thickness. There is no information about material filtration properties using polydisperse test dust. The manuscript presents methodology and experimental test results of five samples A, B, C, D and E, filter materials differing in their chemical composition and structure parameters. In the first stage, efficiency characteristics φ(w), filtration accuracy d(zmax) and the flow resistance Δp(w) depending on the dust absorption coefficient k(m) of three filter cartridges of each material, A, B, C, D and E, were determined. Then, from each material characteristics of one piece was selected in order to compare their initial and initial period efficiencies as well as changes in the flow resistance depending on the dust absorption coefficient k(m). Obtained results showed that the filter materials differ significantly in efficiency and accuracy values in the initial filtration period. Initial period duration is also different, i.e., filtration efficiency increasing time to a certain value, which for materials with a nanofiber layer is much shorter, which minimizes engine component wear. For materials with nanofibers, flow resistance increase intensity is greater, which results from surface filtration. Filtration efficiency of each filter material sample A, B, C, D and E was assessed with the filtration quality coefficient including the efficiency and flow resistance. In the available literature, the problem of increasing filtration efficiency in the initial period is known, but there are no results for specific filter materials. Research shows that filter material characteristics are closely related. Each increase in efficiency and accuracy of intake air filtration reduces engine components wear, but it is related to flow resistance increase in the engine intake system, which reduces its power, and increases need for more frequent filter servicing.