Fuel filter for diesel engine: device, replacement, operating principle

The engine power system includes a lot of important elements, including filtering ones. They are present on both petrol and diesel engines. As for the latter, such engines are more demanding on the quality of fuel. Therefore, the fuel filter of a diesel engine is slightly different from gasoline analogues. So, let's look at the design and purpose of these elements.

What is it for?

Even with the best quality of production, diesel fuel is exposed to various impurities. And this is happening in the oil refining industry. Further pollution occurs during its transportation and refueling. It is also worth noting that such a fuel under long-term storage undergoes oxidation, impurities and opacities are formed in it.

Varieties

The fuel filter for a diesel engine can be of two types of purification:

• Thin.
• Rough.

On some models an additional separator is installed. This modular device includes a diesel fuel filter and a dehumidifier. It contributes to the qualitative cleaning of fuel not only from impurities, dirt and tar, but also from water that may arise from condensate. In gasoline cars, separators are not installed, and the coarse cleaning function can be performed by a grid (made of plastic or metal) on a submersible gasoline pump. Therefore, the fuel filter of the diesel engine is slightly different.

Rough cleaning

This element includes a housing inside which there is a reticular mesh. All this is hermetically sealed with a paronit cushion. At the bottom of the element there is a sludge discharge valve. It must be periodically opened, in order to prevent premature filter clogging. Passing through the element, the fuel is cleaned of large particles of dirt. That is, the principle of the fuel filter diesel engine (rough cleaning) is to prevent fuel clogging even before it hits the system and the highway. On some vehicles, the element contains an intake reduction valve. Its purpose is to control the level of working pressure in the fuel system.

Fine cleaning

This element serves for the final filtration of fuel before it enters the pump and spray nozzle. Sometimes the part is installed in the pump itself, but is most often located in the vicinity of the fuel line. This element is non-separable. Therefore, the replacement of the fuel filter on the diesel engine is carried out entirely, without repair and other repairs. By its design, it is a body-glass, inside which there is a cleaning element. The latter is made of porous paper. The pore thickness is not more than 10 μm. This is the maximum value for the injectors and pump. If larger particles get trapped, the system becomes clogged. The fuel itself penetrates into the filter through the fittings. On them it also leaves, but already in a pure state. There are inlet and outlet fitting. They can additionally be equipped with a plastic tube with fittings.

Principle of operation

How is the fuel filter of the diesel engine arranged? The principle of his work is as follows. Fuel from the tank passes through the pipes to the coarse filter, where it is cleaned of dirt up to 25 microns. Then it enters the inlet hose of the fine cleaning element. In the body of the filter, the fuel passes through a porous paper, where, while cleansing of fine impurities, it passes further along the highway. By the way, this paper has the same structure as on the oil filter.

Three-stem

Some cars are equipped with more sophisticated elements. For example, the device of the fuel filter of the diesel engine "Opel Astra" assumes the presence of three fittings. Two of them are the main ones that serve for the entry and exit of fuel. And the additional third performs the function of dumping fuel into the tank, if the pressure in the system exceeds the permissible values. On domestic cars, such a fuel filter for a diesel engine is not installed.

Resource

The service life of gasoline cleaning elements is quite high. The mileage of cars with them is about 90 thousand kilometers. Some manufacturers say that their life is the same as the life of the entire engine. Of course, this can only be achieved with an ideal fuel quality. As for our history, fuel filters "Bosch" for diesel engines serve during the run from 15 to 30 thousand kilometers. Reviews of motorists say that this is a very good model of the filter and there are no problems with using it. Why such a run-in time replacement? This resource depends on the quality of the fuel. Fuel at the gas stations has a different level of contamination, hence such values. The presence of large particles in the element reduces its throughput. By what signs to determine that it's time to change fuel filters for diesel engines? Testimonials of experienced motorists note a decrease in traction, dynamics of acceleration of the car. Sometimes the machine jogs, the engine reacts with a delay to the gas pedal. Floating turns at idle, increased consumption - all this is the cause of the clog.

Replacement

Before you change the fuel filter on a diesel engine, you need to find the location of its location. Often it is in the engine compartment - in front of the fuel ramp. Sometimes, to get to it, you need to remove the plastic engine cover. You can see it immediately by its size and shape (see below). This is the fuel filter for the diesel engine. "Volkswagen Passat TDI" is equipped with them as well. On some cars it is under the bottom. It can immediately be seen on the thick fuel lines, suitable to it. Next, you need to prepare a tank for draining, because when removing the fittings, a small amount of fuel will be spilled. You can go and another way - to make the system work on the remaining fuel, and so that it was in the tank, but was not in the right place for us. To do this is very simple - we need to pull out the fuse on the pump and start the car, letting it run on a small part of the fuel that remained after it. The fuse block is to the left of the steering column. On the back cover of it - pinout. If this is a foreign car, remove the fuse responsible for the Fuel Pump. Replacing the fuel filter for a diesel engine is quite simple. To do this, you need a minus screwdriver or a wrench (usually "for 12"). We remove the connection to the inlet and outlet, and also unscrew the bolts securing the filter. Install the new element in place. Some motorists buy a filter for diesel engines with heating. This is a very useful function that prevents the fuel from freezing and the accumulation of paraffin on the walls of the paper. When installing a new element, it is important to follow the direction of filtration. It is indicated by a special arrow. Its beginning is the input choke. At the end, an outlet pipe is installed, from which pure fuel will flow into the injectors. Do not confuse the arrow, otherwise the system will be clogged. After installation, carefully check the reliability of all connections. Tubes should not be fierce, and the filter itself - hang on the mounts.

Requirements

A quality element provides not only reliable protection against dirt, but also moisture. It can accumulate on the walls of a half-empty tank when the car was parked for the night. Low-quality filters do not protect the system from condensation, which causes moisture to fall onto the ramp, and then into the combustion chamber. As a result, the inner part of the trunk rusts, and the compression of the motor falls due to improperly prepared mixture. Another requirement is that the filter should work qualitatively even at negative temperatures. Cold contributes to the crystallization of fuel, because of what it turns into paraffin. To prevent this from happening, the filter is equipped with a heating system. The sensor monitors the temperature in the tank and provides the optimum mixture at engine start-up. If you live in the northern latitudes, be sure to put a heated filter. In its absence, thick fuel quickly clogs the cleaning element, and sometimes even gets into the injection system, because of which the motor loses power and does not start.

Replacement for case analysis

If you need to disassemble the housing of the old filter (cartridge) to install the element, be sure to clean it. When used on its walls, sediment forms, which can be discharged through the lower drain valve. But if there is none, you will need a rune vacuum pump. It sounds like something complicated and technological, but this can be a normal medical syringe. Putting its handle up, you will collect all the accumulated inside sucks. It's not just dirt, it's water. Further, if the walls are also contaminated, wipe them with a dry, fleecy rag. Before installing a new filter, the cartridge must be perfectly clean. Check the condition of the O-ring. If it is stretched or has signs of wear, replace it with a new one. Then close the lid, connect all the hoses and turn on the ignition for a few seconds. The fuel pump will begin to pump the diesel into the chuck. Then you can safely start the engine.

So, we found out the device and the principle of the fuel filter for the diesel engine, and also learned how to change it independently.