The fuel filter does not distinguish between inside and outside. A filter refers to an accessory that filters impurities or gases through filter paper, generally refers to a car filter, which is an engine accessory. The most common location for a fuel filter is in the fuel tank, at the connection of the fuel lines in the chassis of the vehicle:
1. There are three types of fuel filters: diesel filters, gasoline filters and natural gas filters. Its function is to filter out harmful particles and moisture in the engine fuel gas system to protect the oil pump nozzle, cylinder liner, piston ring, etc., reduce wear and avoid blockage;
2. There are various impurities in general gasoline, and a certain amount of dirt will be deposited in the fuel tank after long-term use. The above reasons will affect the quality of gasoline. The function of the gasoline grid is to filter the above impurities. The gasoline in the fuel tank reaches the combustion chamber of the engine through the filtering of the gasoline grid, and its cleanness and purity can be effectively guaranteed;
3. The structure of the diesel filter is roughly the same as that of the oil filter, and there are two types: replaceable and spin-on. However, its working pressure and oil temperature resistance requirements are much lower than those of oil filters, while its filtration efficiency requirements are much higher than those of oil filters. The filter element of diesel filter mostly uses filter paper, and some also use felt or polymer material.

The role of the fuel filter:
1. Filter out the impurities in the filtered medium. The filtered medium can be liquid or gas. The common ones are solid-liquid separation, liquid-liquid separation, and gas-liquid separation;
2. The function of the diesel filter is to filter out harmful impurities and moisture in the fuel system, protect the normal operation of the engine, reduce wear, avoid blockage, and improve engine life;
3. The filter is used to separate wear particles, separate impurities to prevent them from blocking the circulation, separate water to prevent corrosion, freezing and damage to the operating medium and devices, and to protect the operating surfaces of the engine's moving parts from wear.