Classification of fuel filters
There are three types of fuel filters: diesel filters, gasoline filters, and natural gas filters. Its function is to filter out harmful particles and water in the engine fuel system, to protect the oil pump nozzle, cylinder liner, piston ring, etc., reduce wear, and avoid blockage.
The structure of diesel filters is roughly the same as that of oil filters, with two types: replaceable and rotary. But 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 filters is mostly made of filter paper, and some also use felt or polymer materials. In addition to filtering mechanical impurities in diesel, diesel filters also have an important function of filtering water. The presence of water poses great harm to the fuel supply system of diesel engines, as rust, wear, jamming, and even deterioration of the combustion process of diesel can occur. The main water removal method of diesel filtration system is sedimentation. Either a settling chamber is installed at the bottom of the filter, or a specialized settling device is used. Both the sedimentation chamber at the bottom of the filter and the specialized sedimentation tank are equipped with a drain valve. When the water accumulates to a certain amount, the valve is opened to drain the water.
There are two types of gasoline filters: carburetor type and electronic fuel injection type. For gasoline engines that use carburetors, the gasoline filter is located on the inlet side of the fuel pump with low working pressure and generally uses a nylon shell. For electronic fuel injection engines, the gasoline filter is located on the outlet side of the fuel pump with high working pressure and usually uses a metal shell. The filter element of gasoline filters often uses filter paper, as well as nylon cloth and polymer materials.
The function of a fuel filter is to remove solid impurities such as iron oxide and dust contained in the fuel, preventing blockages in the fuel system (especially the fuel injectors). Reduce mechanical wear, ensure stable engine operation, and improve reliability.

Working principle of fuel filter
Generally, there are various impurities in gasoline, and long-term use of the fuel tank can also deposit some dirt, all of which can affect the quality of gasoline. The function of the gasoline compartment is to filter out the above-mentioned impurities. The gasoline in the fuel tank is filtered by the gasoline compartment and reaches the combustion chamber of the engine, effectively ensuring its cleanliness and purity.

Performance characteristics of fuel filters
If the filter is installed in the fuel pipeline, it is called an external filter; On the contrary, an internal filter refers to the filter installed inside the fuel pump and fuel tank. The fuel tank filter or its protective cover is usually considered a maintenance free component.
Many imported cars use Banjo FITting connections for their fuel filters. To ensure the reliability of the connection seal, the same sealing gasket must not be used repeatedly. In addition, even if a brand new sealing gasket is used, the sealing performance after the connection is tightened must be checked. When the fuel system needs to replace the O-ring, it is necessary to ensure that the specifications and models of the O-ring are accurate and correct, and to verify whether the elasticity and hardness of the O-ring are appropriate.
The fuel system without a circuit only has one internal filter (inside the fuel tank). Although this all-in-one pump, filter, and delivery unit are expensive, appropriate maintenance and upkeep must also be carried out in a timely manner when fuel delivery is blocked or engine performance deteriorates. At the same time, it is necessary to check for faults in all fuel pipelines and for cracks and curling at hose clamps.

Replacement cycle of fuel filter
The recommended replacement cycle for fuel filters should vary based on their own structure, performance, and usage, and cannot be generalized. Most car manufacturers recommend a replacement cycle of 48000 km for their external filters for normal maintenance; The recommended replacement cycle for conservative maintenance is 19200-24000 km. If unsure, please refer to the owner's manual to find the correct recommended replacement cycle. In addition, when the filter hose shows aging or cracks caused by dirt such as mud and oil, it needs to be replaced in a timely manner.

Maintenance and upkeep of fuel filters
The fuel filter is a consumable material that needs regular replacement and maintenance during vehicle use, otherwise it will not provide qualified protection. Please refer to the instructions provided by each filter supplier for the specific replacement cycle.
Suggested replacement time: Every 20000 kilometers driven by the car.

Precautions for replacing gasoline filters
1. After replacing and installing the gasoline and oil grids, pay attention to the sealing of the interface and be alert to oil leakage;
2. For air and air conditioning grids, it is necessary to ensure the overall sealing after replacement;
3. Take care of the gasoline grid and try to use the matching grade gasoline specified by the car manufacturer.
The filter has arrow markings on the inlet and outlet of the oil, so do not install it upside down when replacing it.

The Development of Fuel Filters
Chinese filters have been around for over 30 years, starting from the establishment of national testing standards in Bengbu in the 1980s, which propelled the rapid rise of the entire industry. Especially with the Wenzhou model shining brightly, there has been a qualitative leap from car accessories to car parts, from the outside to the inside of the car. However, fuel filters and instant gasoline filters have never been given enough attention. They are the least frequently replaced and most easily overlooked product among the four filters, Gasoline filters have been dormant for many years. With the acceleration of car speed, the rapid rise of oil prices, environmental changes, environmental protection skills, and the reduction of carbon emissions, gasoline filters have been changed from external to internal. From carburetors to electronic fuel injection, the trend of internal gasoline filters has become a trend.