Diesel filter structure roughly the same with the oil filter, there are two kinds of interchangeable and spin-on. However, its work pressure and oil temperature tolerance requirements are much lower than the oil filter, and its filtration efficiency requirements are much higher than the oil filter. Diesel filter cartridge filter paper, but also the use of felt or polymer materials.

Diesel filter can be divided into diesel water separator, diesel fine filter. The main function of the water separator is to separate the water in the diesel. The presence of water is extremely damaging to the diesel fuel supply system, and corrosion, galling, jamming can even worsen the diesel combustion process. Due to the high sulfur content of diesel in China, sulfuric acid may even react with water to corrode engine components when combustion occurs. The traditional method of water removal is mainly precipitation, through the funnel structure. Engine emissions of more than three countries put forward higher requirements for water separation, high requirements require the use of high-performance filter media.

Diesel fuel filter is used to filter the small particles of diesel, diesel emissions in the country three or more mainly for 3-5 micron particle filtration efficiency.