Diesel particulate filter - what is it? Install, flush and replace the particulate filter

In Europe, diesel engines are considered to be among the most popular. But in diesel engines, as in gasoline, fuel does not burn completely. As a consequence, various poisonous and carcinogenic substances are formed in the exhaust gases . In addition, they also have soot, because hydrocarbons do not burn completely. In Europe in the 2000s, the environmentalists developed a standard for the level of harmful emissions into the environment. Automakers, in order for their products to comply with these standards, began to install diesel particulate filter . What this is and how it works, it is necessary to know those who drive diesel. Today we will try to answer all these questions.

Main Functions

In order to better understand the purpose of these devices, it is necessary to touch the topic of exhaust gases. The composition of automobile exhaust contains a lot of particularly toxic and carcinogenic substances. So, carbon monoxide, unburned hydrocarbons, aldehydes, sulfur oxides, tetraethyl lead have a very harmful effect on the environment. In addition, in the exhaust gas of a diesel car, in particular heavy-duty trucks, a large amount of soot contains carbon black.

In order to reduce the concentration of this component, a diesel particulate filter is introduced into the design of a modern car. What is this detail? It's something like a catalyst in a gasoline engine.

How the item looks like

So, this device is designed to neutralize soot - a product formed in the combustion of diesel fuel. There are two types: closed (DPF) and closed with the possibility of regeneration (FAP).

For all its simplicity, in fact, these auto parts for foreign cars have a rather complex device. Regardless of the version, the filter is a metal cylinder. On it there are branch pipes - input and output. The output is connected to the exhaust gas cleaning system.

The main element of the filter is a special matrix, which is made of silicon carbide. It is enclosed in a cylinder of metal. The structure of this matrix is cellular. As for the cross-section of cells, this section is often square. But cells with an octagonal shape are more effective.

In addition, the filter for the diesel engine has several sensors in the design. It is a sensor that captures the pressure difference, and an input and output temperature sensor.

Principle of operation

The size of one particle of carbon black is about 0.05 μm. By chemical composition, this product is nothing more than ordinary carbon. It is very difficult to detain these particles by conventional means due to the dimensions of the element. To capture the soot, it is necessary to use the diffusion principle. To understand what a typical diesel particulate filter is, what kind of device it is, you need to look inside it.

So, the filter inside is a ceramic matrix. This is a whole series of tubes, while the neighboring ends are closed. Inside this matrix, exhaust gases come from the motor side, however, when gases enter the tubes, they simply can not move further. Then through the walls of the tubes they enter adjacent open cavities and can then exit the matrix. In the process of diffusion, even the smallest particles remain inside the filter, which means that it performs its task.

Where is the particulate filter

Find this detail is not difficult. The filter is often installed in the exhaust system of the car. Due to the design features, the part can be found between the silencer and the catalyst. In some cases, the device can be combined with a catalyst and located just beyond the exhaust manifold. There the maximum temperature of the gases, and such a filter has a catalytic coating.

Receptions of operation

To effectively use diesel particulate filter, the price of which is quite high (about 900 euros), it is necessary to properly operate the car. The thing is that in the process of cleaning the exhaust gases, the cells and tubes are clogged with soot. This leads to a decrease in the efficiency of the diesel engine.

The filter capacity is lowered and the resistance to the exhaust gas output is increased. Many manufacturers, in order to increase the life of this stock without the need for frequent replacement, applied a special algorithm for the operation of the filter, when the level of filling is controlled. If the filter is filled so that the engine power is lost, the filter regeneration is started.

The reasons for the decrease in efficiency

There are several reasons why the filters are clogged. The main reason is the quality of diesel fuel. When refueling the car with low-quality fuel, a large amount of soot is formed - the filter quickly clogs, which reduces its service life.

Another reason is the insufficient temperature. So, the soot does not burn completely. The thing is that it is a diesel particulate filter. What is it? It not only retains the particles, but also maintains the temperature for burning them. However, it should be said that this happens when the heating of the exhaust gases is high and is not less than 600 degrees Celsius. At lower rates, the soot will not burn.

Among the reasons for the decrease in temperature, gases are also released somewhat. These are traffic regimes, traffic jams, a violation of the combustion of fuel. So, the temperature in the system will not rise if the speed of movement is low, and the movement is accompanied by frequent stops.

Condition monitoring

In order to be able to monitor the state of the system, the exhaust path of the diesel engine is equipped with instrumentation. It includes temperature and pressure sensors. These elements form signals for the electronic control unit, and it determines whether the filter is full or not. When the element is heavily filled, the cleaning process begins.

How to Clear

In order to restore the efficiency of the engine with a filled particulate filter, it is sufficient to use several simple methods that will help start self-cleaning. Regeneration can be either passive or active. In any case, the process takes place by burning soot and releasing the tubes and channels.

For the regeneration process, an increase in the level of heating of exhaust gases, an additive or a flushing of the diesel particulate filter can be used. Additives will help reduce the temperature at which the soot will burn. A washing with special substances will help clean the filter.

Method of passive regeneration

Such cleaning can be carried out directly by the motorist. The appropriate indicator will indicate the need for regeneration. It is also necessary to start this process if the dynamics or power of the engine is reduced.

The most important thing is to ensure a temperature rise for the exhaust gases. This is done by driving on a car with full load. It is enough to drive 30-40 km, so that the filter is completely cleared and all soot burned out. The second option is the use of special fuel additives.

Active regeneration

This mode can be started automatically by the computer controller. For this, the electronics analyze the information from the temperature sensor and the pressure sensor. It informs the electronic control unit that the filter is clogged and the sensor reports temperature. If it is not enough for soot to burn completely, the ECU can additionally inject fuel in the process of exhaust gases. This will burn the soot in the exhaust. It also allows you to raise the temperature to the desired level.

If there are other equipment in the exhaust path that also increases the heating of the exhaust gases, then the ECU can also use them.

Washing

Special fluids are required for this procedure. The procedure itself as a whole depends only on the type of facility.

So, the filter is removed and closed by its holes. Then inside pour the cleaning liquid in such a way as to fill the entire volume of the filter. Next, the product should be left alone for ten hours, while shaking the filter from time to time. After that, the part is washed with warm water and placed back on the car. There are several types of liquids, and for each - its own way of washing. This should be remembered before performing these procedures.

Washing and cleaning will help prolong the work of the element, because the replacement of the particulate filter is a very expensive pleasure. But sooner or later the time will come. It is recommended to change filters after 180 thousand kilometers.

The deterioration of this design is affected primarily by traffic conditions, fuel quality, and driving style. If the machine is under heavy load, the replacement of this element may be required earlier.

So, we found out what the part in the car is for. The diesel particulate filter, like other auto parts for foreign cars, is an important part of the modern car. This element improves the ecological situation in the world, and this is people's health. Quality ecology is a healthy society and happy children.