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Particulate filter: replacement and selection

When and why is it important to replace a particulate filter?

Lifetime of the particulate filter is about 120 000 – 150 000 operational kilometers. At the end of this period the part should be replaced. Exploitation of a defective particulate filter may cause breakdown of the turbine, connecting rod and piston group, crankcase gases ventilation system, EGR valve and switching of the engine to emergency mode.

Usually, component replacement is performed in case of its critical clogging, when the regeneration system is unable to clean the honeycomb cells from deposit. As a rule, premature soiling of the part is caused by usage of low-quality fuel, short distance driving, when the filter doesn’t reach the temperature required for passive regeneration start, and frequent operation of a vehicle with low level of fuel in the tank. Burning-out of the filter, occurred due to excessive temperature increasing at an attempt to clean serious soiling may also be the cause for replacement.

Lowering of engine power, its unstable idling operation, slow increasing of rpm speed, increasing of fuel consumption, and amount of smoke from the exhaust pipe, more than usual – all these indicate that the time for the particulate filter replacement has come.

How to select a particulate filter

Basically, two types of the particulate filters are used on modern diesel cars: separate or combined with the catalytic neutralizer. The separate one is a honeycomb with cellular structure, encased in a metal body. Capturing of soot particulates is performed with the help of the honeycomb. Usually, special additives which contain cerium are used for cleaning such filters; it promotes soot burning at lower temperature.

The filters with catalytic function differ by catalytic coating, added on their walls, which aids oxidation of unburnt hydrocarbon compounds. Components of this type combine functions of particulate filter and catalytic neutralizer. Due to  series of chemical reactions, they are apt to passive regeneration, which occurs at maximal loads to the engine, and are also equipped with active regeneration systems, which provide periodical cleaning of the filter in cases, when the engine doesn’t operate at the max power.

Honeycombs of the filtering elements may vary by configuration of the cells. The filters with rectangular cells are notable for affordable prices but have lower efficiency and break down earlier. The components with octagonal cells are more advanced and notable for increased filtering area and high efficiency, have continuous lifetime but cost more.

High-quality and reliable particulate filters can be found in the assortment of such famous companies as Walker, Delphi, Vegaz, Bosal, HJS and the other manufacturers.

The components, if they are not combined with catalyst, may be installed before it or after. Moreover, they may vary by mounting method, weight and length, which is important to take into account during selection.