Fuel filter

Car fuel filter under the hood

Marine diesel fuel filter

A fuel filter is a filter element in the fuel line that traps particles of dirt and rust from the fuel; as a rule, it contains cartridges with filter paper. They can be found on most internal combustion engines .

Fuel filters serve a vital function for modern cars that are sensitive to the quality of motor fuels. Unfiltered fuel can contain several types of contaminants, for example, pieces of paint and dirt that could get into the fuel tank when refueling, or rust caused by moisture in steel tanks. If these substances are not removed before the fuel enters the system, they will lead to rapid deterioration and failure of the fuel pump and nozzles, due to the abrasive effect of particles on the high-precision components used in modern injection systems . Fuel filters also increase engine power, as the less pollutants are present in the fuel, the more efficient the combustion .

Fuel filters must be changed at regular intervals. Usually, the old fuel line filter is simply replaced with a new one, although some specially designed filters can be cleaned and reused. If the filter does not change regularly, it can cause clogging and stop passing the fuel flow, causing a noticeable deterioration in engine performance.

Some filters, especially on diesel engines , have a bowl-shaped design for collecting water in the lower part (water is denser than diesel fuel). Water can then be drained by opening the valve at the bottom of the bowl. Many fuel filters contain a water sensor connected to the engine control unit or directly to the driver (via a lamp on the dashboard), which transmit information about the achievement of a certain level of water. It is especially undesirable when water is stretched along the diesel engine fuel system, since the system uses diesel fuel to lubricate moving parts, and if water enters elements that require constant lubrication (e.g., an injection valve), this leads to overheating and excessive wear. This type of filter may also have a sensor that alerts the driver to drain the water.

In the immediate vicinity of the diesel fuel filter, there may be a fuel heater to avoid the formation of paraffin (in case of low temperatures) inside the filter element, which can stop the fuel supply to the engine.