Diesel fine filter is a diesel fine filter designed for the current two-stage filtration commonly used in diesel engines. It forms a two-stage filter together with the diesel fuel-water separator. The fuel-water separator is used to filter the water in the diesel, and the diesel fine filter is the fine particles in the diesel. The purpose of the coarse filter is to trap large particles and replace the general filter. 

The difference between diesel fine filter and coarse filter:

1. Diesel fine filter, as the main filter in two-stage filtration, is also the last line of defense against impurities, and has high requirements for filtration efficiency and service life;
2. At present, for diesel heavy trucks of the National Three Standards, the filtration efficiency of 35 micron particles is required to be as high as 98.6, the filtration efficiency of particles above 510 microns is 99.8%, and the filtration efficiency of particles above 10 microns is required to be 99.9%;
3. While ensuring high filtration efficiency, it must also meet the small flow resistance to ensure the reliable operation of the engine and sufficient power;
4. The strainer is mainly used to retain large particles. Most hydraulic systems have strainers from the tank inlet to the pump suction inlet. The coarse filter is used to replace the general filter, because the general filter will be blocked, and the pump water or other media cannot enter the pump if it is "starved";
5. However, because the strainer is installed inside the fuel tank, the maintenance of the strainer is often neglected. When silt and heavy dust gather on the strainer of the suction inlet, the pump will quickly cavitation, and it is prone to malfunction.