DPF (Diesel Particulate Filter)

Diesel engines have the exhaust gases in a relatively high content of carcinogenic microparticles. This does not eliminate the emission component with classical catalyst, and has been developed so-called particulate filter that is able to capture more than 95% of carbon microparticles.

A particulate filter is usually referred to as DPF (Diesel Particulate Filter) or FAP (Particules and Filters). This device allows diesel engines to achieve lower production of solid particles and meet the emission regulations . In any diesel engine generates solid fuel combustion particles (soot), their number depends on the quality of combustion. It depends on many engine parameters, such as air intake, injection, and flame distribution, but also the composition and quality of fuel.

Principle:

Particulate filter consists of a ceramic body with honeycomb structure formed of silicon carbide, which is located in a metal casing. Filter housing through the exhaust gases through a porous ceramic wall, in which solid particles are retained. To avoid clogging and clogging the filter, the captured particles are burnt and converted to carbon dioxide (CO ₂₎ - the so-called filter regeneration.

Regeneration of the filter (so-called burn-out) is an automatic process lasting a few minutes and do not affect any external manifestation of the engine. The actual process of combustion of solid particles happens at temperatures from 600 to 650 ° C. However, such temperatures reach combustion in diesel engines only at maximum load. Therefore, achieving ignition temperatures addressed in two ways:

System with additive
The auxiliary tank is automatically fed directly additive to the fuel tank every time it is refueled. Additive in the tank will last approximately 100.000 km according to the manufacturer, and its volume is controlled by electronics. In the case of the reduced amount of additives, the driver is asked to visit the service.

System without additive
This system works without any additives and is maintenance free. There are two modes of operation:
▪ passive regeneration - exhaust gas at temperatures from 350 to 500 ° C, catalytic combustion to convert the captured particulates to CO ₂
▪ active regeneration - after about 1000 kilometers through the short-term changes of the combustion process the temperature of exhaust gases at 600 ° C and occurs in the combustion in the filter

History:

Particulate filter was used at stationary machinery already in 1980. The car came much later, we can say that when the boom of diesel engines for passenger cars and stricter emission regulations . The first standard-fitted diesel particulate filter appeared in the new generation of engines HDi (Peugeot and Citroen) until 2000. Its implementation into production can be considered as an important step, as was the introduction of catalytic converters.

What You Did not Know:

Can I use biodiesel when the car has a diesel particulate filter?
Biodiesel (RME - Rapeseed methyl ester) for technical reasons can not be used for vehicles equipped with diesel particulate filter. Biodiesel has a higher reaction temperature than diesel, because it could be incomplete regeneration. As a result of more frequent regeneration phases

What are solids?
In any diesel engine resulting from the burning of diesel particulate matter (soot, particulate matter, PM). The particles consist of a number of different substances. The base consists of carbon particles of about 0.05 microns, which is the winding of various hydrocarbons, water, and coming from fuel and oil residues. There is also a small amount of metal oxides generated by abrasion inside the engine. Solid particles are carcinogenic, so they are dangerous.