The fuel filter is connected in series between the fuel pump and the throttle body inlet port. The role of the fuel filter is to contain in the fuel in the iron oxide, dust and other solid debris removed to prevent the fuel system plug (especially the nozzle). Reduce mechanical wear, ensure stable operation of the engine, improve reliability. The structure of the fuel is composed of an aluminum shell and a stainless steel rigid bracket, which is composed of high efficiency filter paper on the bracket, and the filter paper is chrysanthemum-shaped to increase the circulation area. EFI filter can not be used with the oil filter. As the EFI filter often withstand 200-300KPA fuel pressure, so the filter pressure strength is generally required to reach more than 500KPA, and the oil filter is not necessary to achieve such a high pressure.

Diesel filter structure is roughly the same with the oil filter, there are two kinds of interchangeable and screw-mounted. But its work pressure and oil temperature requirements are much lower than the oil filter, and its filtration efficiency requirements are much higher than the oil filter. Diesel filter filter using filter paper, but also the use of blankets or polymer materials.

Diesel filter can be divided into diesel water separator, diesel fine filter. Oil and water separator is an important function of separation of diesel water. The presence of water for the diesel engine fuel system is extremely harmful, corrosion, wear, stuck and even worsen the combustion process of diesel. Due to the high sulfur content of diesel in China, even when the combustion occurs, it will react with water to produce sulfuric acid corrosion engine parts. The traditional way of removing water is mainly precipitated through the funnel structure. More than three emissions of the engine on the water separation of higher requirements, high requirements on the need to use high-performance filter media.