Like gasoline engines, diesel engines are equipped with an exhaust gas filter. But, since the principle of fuel ignition for engines of these two types differs, the exhaust gas filters for a diesel and gasoline engine differ significantly from each other.
It is worth noting that if catalytic converters are installed in the exhaust system gasoline engines a long time ago, particulate filters began to be installed in without fail on diesel engines much later - after the introduction of environmental standards Euro-5.
From the very name of the device, it is clear that its main task is to filter the engine exhaust from the contained soot particles. particulate filter modern diesel delays up to 90% of the amount of soot contained in the exhaust. Externally particulate filter is a small metal cylinder filled with a special heat-resistant ceramic material. Due to the cellular structure of the ceramic filler, the filter retains the smallest particles resulting from combustion. In fact, the particulate filter is a part of the muffler designed to clean the exhaust.
The principle of operation of the particulate filter
work particulate filters it is customary to break it down into two stages: direct filtration of exhaust gases (soot capture) and filter regeneration. At the stage of soot capture inside the filter, in contrast to the catalytic converter of a gasoline engine, no complex chemical or physical processes. The special fine-mesh ceramic structure of the inner part of the filter sifts exhaust gases, retaining soot particles on its walls. At the same time, even the most efficient filters are not able to completely eliminate the ingress of soot into the atmosphere, passing microparticles ranging in size from 0.1 to 0.5 microns. However, the content of particles of this size in the exhaust of a diesel engine does not exceed 5-10%.
Naturally, over time, the amount of soot trapped in the filter reaches a critical level - the filter becomes more and more clogged, and after a certain point this begins to affect performance. power unit in general: engine power drops, fuel consumption rises. The second stage of operation of the device is aimed at cleaning or regenerating the particulate filter. Unlike the filtration process, the filter regeneration step is very complex process. The regeneration of particulate filters is implemented by different automakers in different ways. True, the essence of all these solutions is the same - cleaning the filter cells from clogged soot.
In most cases, the particulate filter is a combined device that combines an anti-particulate filter element and a catalytic converter for harmful exhaust gases. A typical example are particulate filters used on their cars by Volkswagen. Thus, the developers not only implement the requirements for exhaust cleaning, but also provide a process for cleaning the particulate filter element. The device of the combined filter is as follows: inside the filter housing there are heat-resistant cells made of silicon carbide with channels of a minimum cross section. These cells are a filter element that fights soot. The inner sidewalls of the filter housing are made of a special catalytic material (usually titanium), which contributes to the oxidation and combustion of carbon monoxide and carbon dioxide. Additional function converter in this case lies in its ability to heat the particulate filter to a temperature of about 500 ° C. As a rule, this temperature is quite enough for the accumulated soot particles to simply burn out by themselves, thereby cleaning the filter cells. This process is commonly referred to as passive particulate filter regeneration.
However, efficiency passive regeneration particulate filter on a diesel engine is achieved only with a relatively long work engine under load, for example, on a long trip along a country road to high speeds. After all, only then a high temperature is reached in the filter, sufficient to burn out the accumulated soot. If the soot filling has reached a critical level, and it is not possible to warm up the filter due to insufficient load on the engine (driving short distances or infrequent movement around the city), but at the same time, the sensors record filter clogging beyond allowable rate, active particulate filter cleaning starts. This process involves the supply of an additional portion of fuel into the engine cylinders after the main part of diesel fuel. Then the EGR valve is closed, and if necessary, the electronics temporarily changes the algorithm for the standard control of the turbine geometry. not burnt out fuel mixture enters the catalyst through intake manifold, after which the afterburning of the mixture occurs, significantly increasing the temperature exhaust gases. Exhaust gases entering the particulate filter reach 500-700 ° C and instantly burn out soot from clogged filter cells.
An obvious indication of the start of the process of active filter regeneration will be unexpected short-term emissions of black smoke. At the same time, the instruments will show an instant and short increase in engine speed at idle with a simultaneous surge in fuel consumption. It is worth noting that the entire forced cleaning procedure is fully automated and does not require the intervention of the machine owner. Electronics reads data from sensors installed before and after the filter, upon recovery right level pressure, the active regeneration process ends, and the engine returns to normal mode.
Some manufacturers that do not use combined diesel exhaust aftertreatment devices use filters with a separate catalyst. Here, the filter is cleaned by automatically injecting a special additive into the fuel. When the particulate filter is filled and the engine power drops, the injection system pumps the additive into the fuel. After combustion of such a mixture in the exhaust system, an extremely high temperature exceeding 600 ° C is reached. In addition, the active substance of the additive does not decompose when burned with diesel fuel, but enters a hot particulate filter, where, when burned, it raises the temperature to 900 ° C, providing instant burning of soot and quick cleaning of the filter. Given the short duration of exposure over high temperature and the strength of the materials from which the filters are made, the exhaust system is not destroyed.
Removing the particulate filter - methods and consequences
Unfortunately, frequent regeneration negatively affects the engine of the machine. During regeneration, the rich fuel mixture does not burn completely and enters the engine oil. As a result, the oil liquefies, increasing in volume. The protective and lubricating properties of the oil are reduced, in addition, liquid oil easily overcomes seals, causing the risk of getting into the intercooler and cylinders.
The service life of particulate filters reaches 110-120 thousand kilometers of the car. However, considering low quality domestic diesel fuel, it is not uncommon for a filter to be replaced on a new car after 25-30 thousand kilometers. Depending on the model of the car, the cost of a filter for the exhaust system of a diesel engine ranges from 900 to 3000 euros.
An effective alternative to replacing the particulate filter is to remove it. By removing the filter, the owner of the machine will save himself from the problems associated with regular blockages and the need to clean the device. Traction characteristics of such a car increase noticeably, and fuel consumption decreases. In addition, there is no need for special engine oils required for vehicles with diesel particulate filters. With regard to possible negative consequences removing the filter, then correct dismantling devices besides ascending harmful emissions products of fuel combustion to the level of Euro-3 requirements, nothing bad will happen to the car.
Today, many car services offer a diesel particulate filter removal service. However, trusting "garage" specialists is quite dangerous. This option is fraught with damage to the sensors of the exhaust system, which leads to the inclusion emergency mode car operation and subsequent repairs. In order to properly remove the particulate filter, several steps must be followed, including a preliminary computer diagnostics, ECU reprogramming and subsequent technical dismantling of the device.
The advent of the diesel engine on the mass consumer market forced the developers of such motors to bring them to world environmental standards. Diesel engines must effectively deal with exhaust gases, detaining elements that are dangerous for emission into the atmosphere. During the modernization of the exhaust gas system of diesel engines, diesel particulate filters began to be installed everywhere, which effectively clean the exhaust. During operation of the diesel engine, the diesel particulate filter becomes dirty and must be cleaned or replaced.
Table of contents:What is a DPF particulate filter: task and principle of operation
As the name implies, the task of a diesel particulate filter is to keep soot particles as they appear in the exhaust. Soot accumulates in it, which is then burnt out, thereby achieving a less harmful environment exhaust.
Principle of operation DPF filter in the following:
- Soot accumulates in the filter up to a critical moment, which depends on the pressure difference before and after the filter element;
- When this pressure deviates from the norm, that is, the throughput of the filter decreases, the electronic unit engine management receives information about this and activates the afterburning mode of accumulated soot;
Please note: Depending on the engine manufacturer, the afterburning process may be activated under different conditions. - The afterburning process takes place at an increased rotational speed crankshaft and enhanced fuel injection, the command to which is given by the control unit;
- This increases the temperature of the exhaust gases to values at which soot burns out.
Despite the presence of a soot afterburning mode, nevertheless, it can accumulate in the DPF filter and not burn out. This is especially true for drivers who rarely operate the car when increased speed moving mainly in urban areas.
Since the cost of the DPF particulate filter is quite high, drivers need to monitor these elements and clean it in a timely manner so as not to encounter the need for replacement.
Causes of clogged diesel particulate filter
Soot - by-product working off diesel fuel in the engine cylinders. IN exhaust gases it is presented in the consistency of a fine powder, which is retained almost completely by the particulate filter mesh.
During the operating cycle, hydrocarbon particles that go into the exhaust do not burn in the chamber. Because of them, they begin to form resinous deposits. This resin sticks together small soot particles, which leads to the formation of soot. In a place with soot in this soot, there are other elements of burning diesel fuel, as well as metal sulfates that occur in the exhaust due to the combustion of oil that has entered the cylinder.
Please note: Metal sulphates are a combustion product of fuel additives containing metallic elements. Especially a lot of metal-containing additives are found in universal oils, which can be used for diesel and gasoline engines. This is one of the reasons why such oils are not recommended for regular use in diesel engines.
The result of the processes described above is the formation of soot deposits with particles of other elements that settle on the filter and do not burn out in the soot afterburning mode.
What determines the life of the particulate filter
Depending on how carefully the owner of the car approaches the issue of clogging of the particulate filter, the service life of the element is directly correlated. Also, the service life is affected by the number of activation of soot afterburning modes. The more often the car engine activates the soot afterburning mode, the less the diesel particulate filter will last.
Experts recommend to increase the service life of the particulate filter, especially if a car with a diesel engine is operated within the city, to clean this element at each MOT. It is especially important to do this if there are engine problems that can lead to the formation of massive deposits on the filter element.
Please note: A clean particulate filter is also economically efficient. If the filter is dirty, the engine power is reduced, which increases the engine consumption to drive the car with the same dynamics.
It is possible to increase the life of the particulate filter if you use special additives for diesel fuel. In automotive stores, you can find additives that are aimed at reducing the amount of carbon deposits formed as a result of the operation of the motor. This is achieved by maximizing the combustion of fuel in the engine cylinders, which leads to a reduction in the amount of soot in the exhaust gases. It is recommended to use such an additive at least once every 3000 kilometers of the car.
Also, the process of soot formation on the particulate filter is strongly influenced by the quality of the fuel used, so you need to refuel with high-quality diesel in order to maximize the life of this element.
How to clean the DPF particulate filter
There are two main ways to clean the DPF particulate filter from carbon deposits. The first implies the need to remove the filter element from the car, and the second involves performing actions directly on the car. Both methods have their advantages and disadvantages, so we will consider them separately.
Cleaning the particulate filter with removal
Complexity this method consists in the need to dismantle the diesel particulate filter, as well as the duration of the procedure. On average, it will take about 8 hours to clean the filter.
For cleaning, special diesel particulate filter flushing fluids are used, which can be purchased from car shops. It is better to choose the compositions of proven brands such as Luffe, Pro-tec, Liqui Moly and the like. These fluids are compositions of petroleum components and various additives that can dissolve soot deposits. Liquids are supplied in 5-liter canisters, on average, the entire canister is required for one flush. Canisters on top can have a place for attaching a hose, some of them have a hose included. The hose makes it easier to fill the particulate filter with flushing fluid.
The housing of the removed particulate filter must be completely filled with flushing fluid and left for the time specified in the instructions for use of the composition (about 8 hours). After that, it is enough to rinse the filter with a jet of water to wash off the remaining dirt, as well as the remnants of the cleaning agent.
Please note: Washing with water must be taken seriously as the cleaning agent is flammable and may ignite if exposed to exhaust fumes.
After washing the particulate filter with water, it remains to dry it and install it in place.
Cleaning the particulate filter without removing
The method of flushing the particulate filter without removing it is faster, since the work is carried out directly on the car. Design features filters allow you to supply cleaning fluid through the hole for installing a pressure or temperature sensor, after removing them.
It is important to note that a different composition is used to clean the particulate filter without removal. This is due to the fact that the work is carried out directly on the car, and there is no way to make sure that the oil products will be completely removed from the particulate filter. Therefore, a water-alkaline-based composition is used for cleaning. with flushing fluid. The liquid will allow after cleaning to neutralize the remaining alkali.
To flush the particulate filter without removing it, you will need to acquire a spray gun.
Please note: You can also find initially flushing liquids in aerosol cans. For the effective use of the liquid in the can, be sure to read the instructions for it.
Before washing the particulate filter, the car engine must be warmed up, after which it is necessary to wait until the temperature of about 40 degrees Celsius is established in the filter element. This must be done to improve the efficiency of the alkaline composition.
The composition is sprayed onto the particulate filter at a pressure of about 8 bar. In this case, the spraying process should be interval: 10 seconds the liquid is injected, then 10 seconds must be waited before injecting a new dose. Thus, it will be necessary to introduce about 1 liter of cleaning fluid. It is also important to rotate and move the spray probe in order to clean the entire particulate filter. After washing with an alkaline composition is carried out, pure water is sprayed in a similar way.
After cleaning the particulate filter with liquid agents, it is recommended to carry out the procedure for burning off soot residues by operating the car at high speeds for 20-30 minutes.
In the emission legislation EURO 6c, the limit values for particle mass (PM) and particle number (PN) are even more severely restricted. The basis for this is the fact that modern internal combustion engines With direct injection does not create such a homogeneous fuel-air mixture, as with injection into the intake manifold.
Therefore, when fuel is burned, more particles are formed. In order to comply with the limit values, among other things, a diesel particulate filter is installed for gasoline engine.
Example: B48 engine on F22/F23
Description of operation
Mounting position of the diesel particulate filter for petrol engines
A particulate filter for a gasoline engine is installed in place of the middle muffler behind the catalyst. In the future, the diesel particulate filter for a gasoline engine will be installed closer to the engine in a common housing with a catalyst.
For unambiguous identification, the mounting position of the charge pressure sensor must be checked.
If the exhaust gas pressure sensor is located at the catalytic converter outlet, then the diesel particulate filter for the petrol engine is located farther from the engine in the underbody of the vehicle instead of the middle muffler. If the exhaust gas pressure sensor is centrally located on the catalytic converter housing, then the diesel particulate filter for the petrol engine is installed closer to the engine.
The mounting position of the diesel particulate filter closer to the engine facilitates regeneration (soot burning), since the required exhaust gas temperatures are more easily reached.
Design and function of a particulate filter for a gasoline engine
The particulate filter for a gasoline engine is penetrated by many channels through which the exhaust gases pass. The walls of the particulate filter for a gasoline engine are porous for the passage of exhaust gases. Particles (soot and ash) settle in the channels.
The channels of the diesel particulate filter for a gasoline engine are closed at the edges. Each inlet is surrounded by 4 outlets. Particles settle in the coating of the inlet channels. Particles remain there, which burn out when the temperature of the exhaust gases rises and required quantity oxygen. The cleaned exhaust gas permeates through the porous, coated walls of the exhaust ports.
Soot deposits clog the diesel particulate filter over time. Therefore, they should be burned. This occurs when the temperature of the exhaust gases exceeds the ignition temperature of the soot. This process called regeneration. In doing so, the carbon particles are converted into gaseous carbon dioxide (CO2 ) by oxidation.
Soot deposits begin to burn off at temperatures above 600 °C. Fast and efficient regeneration is only achieved from a temperature of 700 °C. Because given temperature is achieved only at a corresponding high load, along with natural regeneration (soot burning with excess air in the forced air mode). idle move) diesel particulate filter for gasoline engine apply additional measures. So the temperature of the exhaust gases is artificially increased by adjusting the ignition angle. As a rule, the driver does not feel these processes.
Exhaust pressure sensor
In a petrol engine, compared to a diesel engine, the pressure difference is not measured before and after the particulate filter. Instead, the gas pressure sensor in the petrol engine measures the exhaust gas pressure upstream of the petrol particulate filter and the ambient pressure.
Digital electronic system The engine management system (DME) uses the signals from the boost pressure sensor and other signals (e.g. air mass) to calculate the exhaust gas flow.
Based on the exhaust gas flow in combination with the measured ambient pressure, the exhaust gas pressure after the diesel particulate filter is calculated for the petrol engine. The calculated differential pressure before and after the diesel particulate filter for a petrol engine indicates the degree of loading of the diesel particulate filter for a petrol engine. the digital engine electronics (DME) activates regeneration when the permissible load level is exceeded.
System functions
Regeneration
Depending on the driving style and condition of the vehicle, the diesel particulate filter is designed for approximately 240,000 km. When this mileage is reached, the diesel particulate filter for a gasoline engine must be replaced together with the housing. To do this, the exhaust system is removed and a new particulate filter for a gasoline engine is installed.
Information about the degree of loading is provided by the diagnostic system. Upon reaching maximum mileage a fault memory is stored and read by the diagnostic system. In t / s, after reaching the maximum mileage, service information is not displayed.
To keep the exhaust gas pressure in acceptable limits the number of regeneration cycles increases as the degree of ash loading of the diesel particulate filter for a gasoline engine increases. At the maximum degree of ash loading of the diesel particulate filter for a gasoline engine, it is not able to burn through freely. As a result, there is a gradual decrease in engine power. If the power reduction exceeds 30%, the digital engine electronics (DME) activates signal lamp exhaust gas toxicity. The engine management system goes into emergency mode.
| Designation | Explanation | Designation | Explanation |
|---|---|---|---|
| A | Soot | B | Ash |
| C | New condition (no deposits) | ||
| km | Mileage | kW | Power in kW |
| millibar | Exhaust pressure in millibars | ||
| 1 | Load cycles with regeneration | 2 | High loading diesel particulate filter for gasoline engine |
| 3 | Average mileage reached | 4 | Power reduction and emergency program |
Regeneration capabilities
- Normal regeneration: carried out depending on the nature of the movement. Soot burning is only possible if there is too much air in the forced idle mode in the forced idle mode and at a correspondingly high exhaust gas temperature.
- Calculated regeneration: cyclic regeneration based on the nature of the movement.
- Regeneration every 10,000 km: set regeneration cycle.
Injection
To improve emission parameters harmful substances(particles) for EURO 6c new nozzles are installed. The injectors have a new injection geometry. The following graph shows the change:
Service Instructions
General instructions
Diagnostic instructions
The particulate filter for a gasoline engine is diagnosed using diagnostic system. For this, test modules are provided for the exhaust gas pressure sensor and the diesel particulate filter for petrol engines.
For the service function, the replacement of the diesel particulate filter for the petrol engine must be registered.
We reserve the right to typographical errors, semantic errors and technical changes.
On cars with a diesel engine, a particulate filter has been used as part of the exhaust system since 2000. With the introduction of Euro 5 standards in January 2011, the use of a particulate filter on passenger cars with a diesel engine is mandatory.
Diesel particulate filter (in English version Diesel Particulate Filter, DPF, in the French version Filtre a Particules, FAP, in the German version RubPartikelFilter, RPF) is designed to reduce the emission of soot particles into the atmosphere with exhaust gases. The use of a filter makes it possible to reduce soot particles in exhaust gases by up to 99.9%.
In a diesel engine, soot is formed when fuel is not burned completely. Soot particles have a size of 10 nm to 1 µm. Each particle consists of a carbon core, to which hydrocarbons, metal oxides, sulfur and water are connected. The specific composition of soot is determined by the mode of operation of the engine and the composition of the fuel.
In the exhaust system, the particulate filter is located behind the catalytic converter. In some designs, the particulate filter is combined with catalytic converter oxidizing type and is located immediately after the exhaust manifold where the temperature of the exhaust gases is maximum. It's called a catalytic coated particulate filter.
Main constructive element The particulate filter is a matrix that is made of ceramic (silicon carbide). The matrix is placed in a metal case. The ceramic matrix has a cellular structure consisting of channels of small cross section, alternately closed on one side and the other. The side walls of the channels have a porous structure and play the role of a filter.
In cross section, the cells of the matrix have a square shape. More perfect are the input cells of the octagonal shape. They have a larger surface area (compared to exit cells), allow more exhaust gases to pass through and provide longer term particulate filter service.
In the work of the particulate filter, two successive stages are distinguished: filtration and regeneration of soot. During filtration, soot particles are captured and deposited on the filter walls. Small soot particles (from 0.1 to 1 µm) are the most difficult to capture. Their share is small (up to 5%), but these are the most dangerous emissions for humans. Modern particulate filters retain these particles as well.
Soot particles accumulated during filtration create an obstacle for exhaust gases, which leads to a decrease in engine power. Therefore, periodically cleaning of the filter from accumulated soot or regeneration is required. A distinction is made between passive and active regeneration of the particulate filter. IN modern filters As a rule, passive and active regeneration are used.
Passive particulate filter regeneration is carried out due to the high temperature of the exhaust gases (about 600 ° C), which is achieved when the engine is running with maximum load. Another way of passive regeneration is the addition of special additives to the fuel, which ensure the combustion of soot at a lower temperature (450-500°C).
Under certain engine operating conditions (light load, urban driving, etc.), the exhaust gas temperature is not high enough and passive regeneration cannot occur. In this case, active (forced) regeneration of the particulate filter is carried out.
Active particulate filter regeneration It is carried out by forcibly raising the temperature of the exhaust gases for a certain period of time. The accumulated soot is oxidized (burns out). There are several ways to increase the temperature of the exhaust gases during active regeneration:
- late fuel injection;
- additional fuel injection on the exhaust stroke;
- usage electric heater before the particulate filter;
- injection of a portion of fuel directly in front of the particulate filter;
- heating of exhaust gases by microwaves.
The design of the particulate filter and the systems that ensure its operation are constantly being improved. Currently, the most popular particulate filter with a catalytic coating and particulate filter with a system for introducing additives into the fuel.
Particulate filter with catalytic coating
Diesel particulate filter with catalytic coating applied to automobiles Volkswagen group and a number of other manufacturers. In the operation of a catalytic coated particulate filter, a distinction is made between active and passive regeneration.
During passive regeneration, soot is continuously oxidized due to the action of the catalyst (platinum) and the high temperature of the exhaust gases (350-500°C). The chain of chemical transformations during passive regeneration is as follows:
- nitrogen oxides react with oxygen in the presence of a catalyst to form nitrogen dioxide;
- nitrogen dioxide reacts with soot particles (carbon) to form nitric oxide and carbon monoxide;
- nitric oxide and carbon monoxide react with oxygen to form nitrogen dioxide and carbon dioxide.
Active regeneration occurs at a temperature of 600-650°C, which is created using the diesel control system. The need for active regeneration is determined based on an assessment bandwidth particulate filter, which is carried out using the following sensors of the diesel control system: air flow meter; exhaust gas temperature before the particulate filter; exhaust gas temperature after the particulate filter; pressure drop across the particulate filter.
Based on the electrical signals from the sensors, the electronic control unit performs an additional injection of fuel into the combustion chamber, and also reduces the air supply to the engine and stops the exhaust gas recirculation. In this case, the temperature of the exhaust gases rises to the value required for recirculation.
Diesel particulate filter with fuel additive system
A diesel particulate filter with a system for introducing additives into the fuel is a development PSA concern(Peuqeot-Citroen). Since the pioneers in the use of additives for regeneration are the French, the name FAP filter (from the French Filtre a Particules) has stuck to the filter. A similar approach is implemented in particulate filters from other automakers (Ford, Toyota).
The system uses an additive containing cerium, which is added to the fuel and ensures the combustion of soot at a lower temperature (450-500°C). But even this exhaust gas temperature cannot always be reached, so the system periodically performs active regeneration of the particulate filter. The diesel particulate filter is usually installed separately after the catalytic converter.
The additive is stored in a separate tank with a capacity of 3-5 liters, which is enough for 80-120 thousand kilometers (filter service life). Structurally, the tank can be located in the fuel tank or outside it. The additive level in the tank is controlled by a float-type sensor. The additive is supplied to the fuel tank by means of electric pump. Additive supply is carried out at each refueling fuel tank proportional to the amount of fuel supplied. The start and duration of the additive supply is regulated by the engine control unit (in some designs, a separate electronic unit).
A side effect of using the additive is that during combustion it settles in the form of ash on the filter walls and is not removed from it, which reduces the life of the device. The service life of a modern diesel particulate filter is 120,000 km. Manufacturers declare release in soon filter with a resource of 250,000 km.
Due to the high cost of exhausted particulate filters, car owners, as a rule, are not replaced, but removed, followed by a flashing of the engine management system.
In Europe, the most popular internal combustion engine is diesel. However, neither in petrol nor in diesel engine fuel does not burn completely. This will result in the formation of toxic and carcinogenic substances in the exhaust gases (EG), including soot particles - products that do not complete combustion hydrocarbons. To avoid this, standards for emissions of harmful substances have been introduced, in order to comply with which, special element- particulate filter.
What is a particulate filter for?
To understand the purpose of such a device, it is necessary to touch on what OG are. The photo below in the table shows the composition of exhaust gases, as well as their effect on the human body.
Data Shows Diesel Is Dangerous high content soot in the composition of the exhaust gas. Here, to reduce its concentration, such an element is introduced into the design of the car - particulate filterconsidered below.
Principle of operation
The particle size of soot is approximately equal to five hundredths of a micron, and in its own way chemical composition it's pure carbon. Retain such microscopic particles by conventional means quite problematic. Diffusion is used to capture them in the device. To understand the principle of operation inherent in such a device, the photo below will help: 
It can be seen from the picture that there is a whole network of tubes in the matrix, and the ends of the neighboring ones are closed with different sides. The exhaust gas enters from the side of the engine, but when it enters the tubes that are closed on the opposite side, they cannot move further. Then they penetrate through the walls into adjacent open cavities and freely leave the ceramic matrix.
At the same time, during diffusion from one cavity to another, even microscopic particles are retained, which means that the particulate filter has completed its task.
Diesel particulate filter device
The diesel particulate filter itself, with its outward simplicity, is a rather complex device. For all its performances, different cars, he is metal cylinder. The cylinder has inlet and outlet pipes for connection to common system exhaust gas cleaning. The filter device can be seen in the above photo. 
Inside is a ceramic matrix, the device of which has already been discussed above. In addition to the matrix, sensors are installed on the particulate filter that control its operation.
Among them it is worth mentioning:
- differential pressure sensor;
- temperature sensor at the inlet and outlet of the particulate filter used.
Depending on the design, the diesel particulate filter can be installed in different ways, as shown in the photo: 
The fact is that the matrix itself can be made both with an internal catalytic coating and without it. In the latter case, a catalyst must be additionally installed on a diesel engine. If a ceramic matrix with a catalytic coating is used in the composition, then it can be combined with a catalyst.
Particulate filter - how best to operate
Proper operation of the car prolongs the life of the particulate filter. The fact is that when cleaning the exhaust gas, the pores in the tubes and the tubes themselves become clogged with soot particles, which leads to a deterioration in engine operating conditions and ultimately does not allow the car to be operated normally.
It is worth mentioning here that the particulate filter, in order to restore its performance without replacement and removal from the vehicle, requires a special mode of operation that differs from the usual filtration process. But we can return to this issue a little later.
Reasons that reduce work efficiency
There can be several reasons why it clogs. One of the main ones is the quality of the fuel used. Poor quality fuel causes increased soot formation during engine operation, as a result of which the particulate filter will very quickly become clogged with these particles, which will significantly reduce its service life.
Another reason can be considered insufficient exhaust gas temperature for complete combustion of soot. The fact is that the particulate filter allows not only to retain soot particles, but also to burn these particles during operation, when the diesel engine provides a sufficient level of exhaust gas temperature. But it must be emphasized that this is possible when the exhaust gas temperature is high and is at least six hundred degrees. At other, lower values, nothing like this happens.
There can be several reasons for the decrease in exhaust gas temperature, including:
- driving mode (with low speed and frequent stops);
- traffic jams while driving;
- violation of the combustion process.
Current state control
In order to ensure control, the exhaust system, which is equipped with a diesel engine, is equipped with instrumentation, including, as already mentioned, a temperature sensor that controls its readings, and a pressure sensor that measures its difference at the ends of the filter. 
Based on the signals generated by the pressure sensor, the control controller determines that the particulate filter is full of unburned fuel residues, and therefore can automatically start the cleaning process. The corresponding symbol appears on the panel.
How to clean - diesel allows this too
Often for recovery normal operation machine, when the particulate filter is filled with particles of unburned fuel, it is enough to use a few simple tricks that trigger regeneration. It can be active and passive. In any case, cleaning occurs due to the combustion of soot particles and the release of clogged pores from them, for which it is used:
- increase in exhaust gas temperature;
- additives that reduce the temperature at which soot burns;
- flushing, in which the particulate filter is cleaned of soot with the help of special reagents.
Passive regeneration
It is carried out by the driver independently when the corresponding indication appears, as well as with noticeable signs of deterioration in engine operation (power drop, decrease in dynamics, etc.).
At the same time, the most important thing is to provide an increase in temperature for the exhaust gas, which happens if you drive three to four dozen kilometers at full load. This mode of movement will ensure the combustion of soot inside and its cleaning. Another option may be the use of special additives in the fuel, leading to a decrease in the temperature of soot combustion.
Active regeneration
Such a cleaning mode can automatically turn on the engine controller. To do this, he analyzes the data that the current temperature sensor transmits to him, as well as the pressure difference sensor. This sensor signals that soot particles have clogged the particulate filter, and the current temperature sensor determines its value. If it is not enough to burn soot, then the controller can carry out, for example, additional fuel injection, carried out during the exhaust gas, which will lead to its combustion directly in the exhaust system and raise the temperature of the exhaust gases to the desired value.
If exhaust system, which is installed on a diesel engine, provides for other measures aimed at increasing the temperature of the exhaust gases entering the particulate filter, then the control controller also activates them.
flushing
In this case, cleaning is performed using special liquids, poured or injected inside. Reagents soften soot and remove it from clogged pores, after which it can be burned when driving a car.
The particulate filter is an integral part modern car and ensures the composition of exhaust gases in accordance with current regulations. Its current state is monitored by the control system, for which a current temperature sensor is used, as well as a sensor that measures the pressure difference. Such a control system allows either the driver to take timely measures to restore the efficiency of the particulate filter and normal technical condition vehicle, or the regeneration mode will turn on automatically, if it is provided for by the design.
