Fuel filters are the most important components of the engine supply system. The use of fuel filters should not be underestimated, because the performance and durability of the internal combustion engine system largely depends on how clean the fuel will be.

But first let's remember what they are, these systems. Let's start with the gasoline engine.

Gasoline injection into the intake manifold. It is also called distributed injection. Fuel supply is carried out by injectors at a main pressure of 3-4 bar. The pressure in the system is created by the central fuel pump and maintained by a pressure reducing valve. The pump is located in the fuel tank, under the underbody or under the hood.

Gasoline injection into the combustion chamber. Another name is direct injection. Here two circuits are involved in the fuel line - low and high pressure. The pressure in the first one reaches 3-4 bar and is created by the same central pump. But the low-pressure circuit has another electric pump feeding the second circuit. From it, fuel at a pressure of 120 bar is fed to the hydraulic accumulator connected to the injectors.

Single-point injection can be considered as a transitional variant from carburetor to injectors. Requirements to it are less strict than to the distributed injection and, as a rule, are not considered separately.

So, fuel filters (fuel filter elements) are devices for those who treat their car with care. Gasoline passes through the filter, leaves harmful contaminants in it and enters the combustion chamber already in a completely clean form. Cleaning takes place in several stages, for this purpose different types of fuel filters are used depending on the engine design, fuel type and operating conditions.

Let's consider the process of fuel purification in more detail. Initial filtration takes place already in the tank - there are pre-filters. Then the fuel enters the system of medium or fine purification - these are straight-through filters or spin-on filters located before the pump. Water separators - an integral part of fuel filters (fuel filter elements) - are also located here.

In some engines, fuel filters are equipped with special elements that heat the fuel (we are talking, as a rule, about diesel engines). This device has a very important function: by heating the fuel, it does not allow paraffin to precipitate in winter, thus preventing contamination.

The filter element of the fuel filter is actively used when working on trucks. The convenience of using such filters is obvious: when the service life expires, it is enough to unscrew the case and replace only the failed fuel filter element.

Now about the diesel engine. Here the fuel can be injected into the prechamber or directly into the cylinder. To achieve efficient combustion, almost all modern diesel engines have fuel injected into the cylinder.

An injector pump is a unit that combines a pump, a magnetic valve for controlling injection and a sprayer for each individual cylinder. This system allows injection pressures of up to 2000 bar to be achieved.

With the advent of modern gasoline and diesel injection systems, the requirements for fuel purity have increased significantly. Moreover, they are constantly becoming tougher. In this case, the material must separate at least 95% of water from the fuel.

For today's automotive practice, some of the figures look exaggerated. In fact, they are promising and should be strived for.

Why do we filter?

Unfortunately, gasoline begins to become contaminated from the moment it is “born” at the refinery. Transportation of fuel in tanks also makes a contribution - they “breathe”, which means they allow dust to pass through.

Gasoline also becomes contaminated at gas stations, where dust enters the tank along with a stream of fuel. And if the tank is not sealed, dust will be sucked into it continuously. And the tank itself may have scale and pockets of corrosion inside.

The same is true for diesel fuel. Organic and mechanical impurities, as well as water, appear in it. Running a diesel engine on such fuel leads to corrosion of fuel equipment, accelerated wear of the cylinder-piston group, loss of power and other unpleasant consequences.

In diesel filters, spiral-pleated arrangement is more often used. This design is the last word in modern fuel purification systems.

By the way, about water in fuel, this headache for diesel drivers. How is moisture separation carried out? There's no secret. We just haven’t told you everything about crepe filter paper. A curtain made from this material helps combat water contained in the fuel. In a situation where ordinary paper is clogged with moisture, crepe paper allows this moisture to pass through, but not immediately, but as local pressure increases. At the exit from the pores, moisture flows in large drops onto the inner wall of the housing or into a sump, if one is provided for in the filter design. The driver opens a special tap and lets the water drain. In a word, a simple operation, especially since in some cars the water level is determined by a special sensor.

Manufacturer's advice

Of course, fuel filters need to be changed on time. Otherwise, the engine will lose power, run erratically and confuse the control unit. If you install a filter that does not comply with the instructions or is from a dubious manufacturer, you can cause serious damage. However, this can be easily avoided by studying brand catalogs.

When working with the power system, special care must be taken - after stopping the engine, high pressure remains in the fuel line for some time. In addition, follow the instructions for installing filters and use the appropriate tool to replace them. And when installing direct-flow filters, pay attention to the arrow on the housing - it shows the direction of fuel movement from the tank to the engine.

And one more important note. When replacing the fuel pump, be sure to install a new filter. This inexpensive operation will avoid the cost of engine repairs.

Related Products

Replacement filter element

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