What is a Partial Filter? Its Structure and cleaning

What is a Partial Filter? Its Structure and cleaning

Its Structure and Principle of Operation

The Particulate Filter is present in every modern diesel machine. It is used to reduce harmful emissions. It is a filter element that clogs regularly and must be cleaned or regenerated. FAP regenerates itself under certain conditions. When this does not happen, it must be cleaned or forcibly regenerated. With the introduction of environmental standards, all cars with self-igniting internal combustion engines must be equipped with particulate filters. Think about why you need them, how they work, and how you care for them.

We will see everything you need to know about the particulate filter, how it is made, and how regeneration works. We will also see what to do in the case of a clogged or faulty filter, how to intervene and how much to spend to always keep the exhaust gases clean and as polluting as possible.

What Is a Particulate Filter?

The very concept of a filter indicates that the part is involved in the cleaning process. Unlike air filters, particulate filters are installed in the exhaust system. This part is designed to minimize the release of harmful substances into the atmosphere.

Depending on the quality of the product and filter elements, this part can remove up to 90% of soot from the exhaust after the combustion of diesel fuel. The work of the Federation Council is carried out in two stages.

  1. Soot removal A smoke-permeable filter element captures particulate matter. They settle into the cells of the material. This is the main task of the filter.

2. This is a procedure for removing cells from deposited soot. This is done when the motor begins to lose power in the associated serviceable system. In other words, regeneration is the restoration of cleanliness of the cell surface. Various modifications use their own technology for cleaning soot.

Where is the particulate filter located?

In some cars, soot is used in combination with catalysts. The catalyst is installed on all modern cars with a gasoline engine. In this case, the filter can be placed in front of or behind the catalytic converter.

Some manufacturers create combination filters that combine the functions of both filters and catalysts. The cleanliness of exhaust gases from diesel engines does not differ from its gasoline analogues. Often, such parts are installed immediately after the exhaust manifold so that the temperature of the exhaust gases ensures an appropriate chemical reaction to neutralize harmful substances.

diesel particulate filter

Similar to the catalytic converters found in modern gasoline cars, the diesel particulate filter can be seriously damaged if the car owner uses the wrong engine oil. In this case, the lubricant can get into the cylinder and burn out with the stroke of the stroke.

In this case, a large amount of soot is released (this depends on the amount of oil flowing in). This should not be present in the exhaust system of a car. This soot enters the filter cells and forms deposits on them. For diesel engines, the European Association of the Automobile Manufacturers has established engine oil standards that meet the requirements of at least Euro 4 environmental standards.


During the operation of the power unit, you can start the physical process of automatically removing the particulate filter from carbon deposits. This occurs when the exhaust gases entering the filter tank are heated above +500 degrees. During the so-called passive autocleaning, soot is oxidized by an incandescent medium and separates from the surface of the cell.

But to start this process, the motor must run at a certain speed for a long time. If the car is congested and often drives short distances, the exhaust gases will not have much time to warm up. As a result, soot accumulates in the filter.

To assist drivers driving cars in this mode, manufacturers of various automotive chemicals have developed special anti-soot additives. With them, you can start automatic cleaning of the filter at an exhaust gas temperature of up to +300 degrees.

Some modern cars are equipped with a forced regeneration system. It injects some fuel that ignites through a catalytic converter. This will heat up the particulate filter and remove plaque. The system works on the basis of pressure sensors installed in front and behind the particulate filter. If there is a significant difference in the readings of these sensors, the playback system is activated.

Some manufacturers, instead of using an additional portion of fuel to warm up the filter, use special additives that are in a separate tank. This additive contains cerium. The regeneration system periodically adds this substance to the cylinder. The additive forces the exhaust gases to heat to a temperature of about 700-900 degrees. If the car is equipped with a variation of such a system, the owner does not need to do anything to clean the particulate filter.


Diesel particulate filters with a modern design are divided into three types:

1.DPF closed-type filter

2.FAP filter with filter element playback function.

The first category includes elements with ceramic honeycombs inside, like catalytic converters. A thin layer of titanium is applied to the walls. The effectiveness of such parts depends on the exhaust temperature—only in this case, a chemical reaction occurs to neutralize carbon monoxide. For this reason, these models are mounted as close to the exhaust manifold as possible.

When deposited on ceramic honeycombs with a titanium coating, soot oxidizes carbon monoxide (the temperature at which the reaction takes place should be several hundred degrees). The presence of sensors allows you to diagnose filter failures in a timely manner. The driver receives a notification from the ECU when the car is tidy.


The FAP filter is also a closed type. The self-cleaning function differs only from the conventional one. Soot does not accumulate in such flasks. The cells of these elements are covered with special reagents that react with hot smoke and completely remove particles from the exhaust pipe.

Some modern cars have a special flush system. This is due to the injection of reagents at the right time when the car is moving, so that soot is removed at the initial stage of formation.

Sometimes, instead of additives, additional fuel is used, which burns out in the filter itself, increasing the temperature in the flask. As a result of combustion, all particles are completely removed from the filter.

What is regeneration?

Filter regeneration is the cleaning or restoration of clogged filter cells. The procedure itself depends on the filter model. It also explains how the car manufacturer set up this process.

Theoretically, soot will not be completely clogged since a chemical reaction will occur. But in practice, this often happens (the reasons are given a little above). For this, manufacturers have developed a self-cleaning function.

If the vehicle cannot clean the catalyst and filter on its own, you can do this procedure yourself. You will need it in the following cases:

  • The car rarely travels long distances (the exhaust does not have time to warm up to the desired temperature).
  • The internal combustion engine was muffled during the regeneration process.
  • Sensor defect: the cleaning procedure does not turn on since the ECU does not receive the required pulses.
  • At low fuel levels, regeneration does not take place, since additional diesel is required.
  • malfunction of the EGR valve (located in the exhaust gas recirculation system).

A sign of filter clogging is a sharp decrease in the power of the power unit. In this case, cleaning the filter element with special chemicals will help solve the problem.

Particulate filters do not require mechanical cleaning. It is enough to remove the part from the exhaust system and close one of the holes. In addition, a universal emulator is poured into the container. It will help remove plaque without having to buy new parts. The liquid should completely cover the contaminated surface. For an hour, you need to shake the parts periodically so that the soot is delayed.

After using the cleaner, the parts are cleaned under running water.

In addition to cleaning the catalyst, the combustion of an additional part of the VTS outside the engine leads to an increase in the temperature of the filter circuit itself, which also partially contributes to its cleaning.

The driver learns that the electronics perform this step to temporarily increase the idle speed during long trips. As a result of this self-cleaning, darker smoke comes out of the exhaust pipe (this is standard since soot is removed from the system).

How to Care for a Particulate Filter

Like other parts exposed to stress, particulate filters require regular maintenance. Of course, if the engine, fuel system, and all sensors are properly configured in the car, soot formation will be reduced, and regeneration will occur as efficiently as possible.

However, you don't have to wait for the engine error light on the dashboard to come on to check the condition of the particulate cells. Car diagnostics will help identify sci-fi blockages at the initial stage.

Its service life can be extended by using a special flush or cleaner that can quickly and safely remove soot deposits from the filter.


Despite the start of automatic cleaning, the particulate filter is no longer usable. The reason for this is the constant work in the high-temperature zone, and during playback this figure rises significantly.

Usually, with proper engine operation and high-quality fuel, the filter can travel about 2 million kilometers. But in some regions, high-quality fuel is not always available. Therefore, you should pay attention to the condition of the particulate filter, for example, every 100 km.

There are times when you run 5 million times and the filter remains intact. In any case, each driver should independently pay attention to the behavior of the vehicle. An important factor that indicates problems with the particulate filter is a significant decrease in engine power. Also, the engine may begin to absorb a large amount of oil, blue smoke may come out of the exhaust system, or make uncharacteristic sounds during the operation of the internal combustion engine.

Can the Particulate filter be removed?

If you simply state, "It is reality to do it." Only the second question remains: what is the point if the car in this case does not meet environmental standards? In addition, the electronic control unit is configured to control the operation of this element. Removing it from the system will cause a permanent software failure in the electronics.

Some people perform this step and cause failure for the following reasons:

  • There is no need to repair additional parts of the machine.
  • New particulate filters are very expensive.
  • The regeneration process does not take place, which slightly reduces fuel consumption.
  • A little, but still, the motor power increases.

However, this solution has many more drawbacks.

  • The first is non-compliance with environmental standards.
  • The color of the exhaust noticeably changes, which causes problems in large cities, especially in summer and traffic jams (there is not enough air anyway, so a nearby puff car has to turn on air circulation in the car).
  • Cars are not allowed to cross borders, so you can forget about traveling to EU countries.
  • If some sensors are disabled, the control unit software malfunctions. To solve this problem, the ECU must be rewritten. The cost of firmware is high, and the consequences are unpredictable. Resetting the data on the control unit raises many questions and prevents the car from being sold at a fair price.

These are just some of the negative aspects of the DPF notch. But they should be enough to drop the idea and start repairing, cleaning, or buying a new particulate filter.

Instead, the conclusion of the

The decision of whether or not to remove the particulate filter from the vehicle's exhaust system is a personal decision for every driver. For older cars, once this problem is solved at the factory level (SF is rarely found), then some newer generation cars will not work without it at all. And the number of such cars has not decreased, since worthy replacements for diesel engines have not yet been released.

If there are constant errors, the ECU can go into emergency mode, so it is better not to experiment with cars with complex electronic systems. In a diesel-powered vehicle, the particulate filter is an essential component of the exhaust. It serves to reduce pollution and maintain maximum engine performance.