What is the function of the Fuel filter?
The fuel filter is connected in series on the pipeline between the fuel pump and the fuel inlet of the throttle body. The function of the fuel filter is to remove the iron oxide, dust and other solid impurities contained in the fuel to prevent the fuel system from clogging (especially the fuel injector). Reduce mechanical wear, ensure stable engine operation, and improve reliability.
The structure of the diesel filter is roughly the same as that of the oil filter. 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, and its filtering efficiency requirements are much higher than those of oil filters. The filter element of the diesel filter mostly uses filter paper, and some also use felt or polymer materials.
Diesel filter can be divided into diesel water separator and diesel fine filter. The important function of the oil-water separator is to separate the water in the diesel. The presence of water is extremely harmful to the diesel engine fuel supply system, rust, wear, and seizure can even worsen the combustion process of diesel. Due to the high sulfur content in Chinese diesel, when combustion occurs, it will even react with water to form sulfuric acid to corrode engine parts. The traditional water removal method is mainly precipitation, through the funnel structure. Engines with emissions from National III and above put forward higher requirements for water separation, and the high requirements require the use of high-performance filter media.
Diesel fine filter is used to filter fine particles in diesel oil. Diesel engines that emit diesel engines above the national level 3 are mainly aimed at the filtration efficiency of 3-5 micron particles.
Gasoline filters are divided into carburetor type and electronic injection type.
For gasoline engines using carburetor, the gasoline filter is located on the inlet side of the fuel transfer pump, and the working pressure is relatively small. Generally, nylon casing is used. The gasoline filter of the EFI engine is located on the outlet side of the fuel transfer pump, and the working pressure is higher , Usually use a metal shell. The filter element of the gasoline filter mostly uses filter paper, but also uses nylon cloth and polymer materials.
Gasoline filter because the combustion method of gasoline engine is different from that of diesel engine, the overall requirements are not as stringent as diesel filter, so the price is cheap.
If the filter is installed in the fuel line, it is called an external filter; conversely, the internal filter refers to the filter installed inside the fuel pump and fuel tank. Among them, the fuel tank filter or its protective sleeve is generally considered to be a maintenance-free component.
So, what is the replacement cycle of the fuel filter?
In fact, the fuel filter must be replaced every 30,000 kilometers in normal use. If the fuel impurity content is large, the driving distance should be shortened accordingly. But generally we recommend replacing it every 20,000 kilometers. For the specific best replacement time, please refer to the instructions on the vehicle user manual.
Notice: When replacing the filter, do not choose a low-quality fuel filter, because the filter element of the inferior fuel filter is made of poor material, which not only has poor filtering effect, but is soaked in the oil for a long time, and the filter element itself will fall off the filter layer and block the oil. As a result, the fuel pressure is insufficient and the vehicle cannot be started. At the same time, it will cause abnormal pressure in the fuel system, directly leading to insufficient engine power or insufficient combustion, damaging valuable components such as the three-way catalyst and oxygen sensor, and causing huge economic losses.