Diesel particulate filter systems explained

DPF stands for diesel particulate filter. The filters are employed to minimize the number of hazardous particles that escape from the system of the exhaust of diesel engines. The intention is to keep the surrounding air cleaner and safer especially in tight areas.

EHC Teknik produces DPF parts for various applications, and we’re more than happy to answer all your questions regarding this technique. Find out more by reading this article.

Euro 5 standards

They are also justified since particulate diesel (soot) emissions cause serious health problems in humans. DPFs reduce diesel soot emissions by 80%, but they aren’t suitable for all. Even if your driving is not mostly urban/stop-start, some changes to your driving habits may be necessary for these systems to function properly.

Since 2009 when the “Euro 5′ standard came into effect, exhaust emissions standards for diesel vehicles of the new generation have mandated the installation of a DPF into the exhaust system. In reality, most cars manufactured prior to 2009 are equipped with the filter in place.

How do diesel particulate filters operate?

Diesel Particulate Filters (DPF) collect soot particles, which prevent them from going through out of the exhaust. As with any filter, one must be cleaned regularly to keep its performance. For DPFs, DPF this process is called “regeneration”. The soot collected is then burned away at high temperatures leaving only ash.

Regeneration can be passive or active

Passive regeneration

Passive regeneration occurs automatically at the speed of the motorway when the temperatures of the exhaust are high. Since a lot of cars aren’t driving on motorways very often, manufacturers of vehicles have developed “active” regeneration. In this manner, the engine management computer (ECU) manages the process.

Active regeneration

If the filter is filled with soot to a set limit (about 45%) it is possible that the ECU will initiate post-combustion fuel injection in order to increase the exhaust temperature and trigger regeneration. If the engine is turned off while the regeneration is being completed, it could not be finished, and the warning light will flash up to indicate that the filter is not fully blocked.

It is possible to complete a regeneration cycle and clear the warning light by driving and increasing the temperature.

  • Effects of active regenerative
  • During active regeneration, you might notice the following symptoms:
  • Cooling fans in operation
  • Increased idle speed
  • Deactivation of Stop/Start automatically
  • A slight increase in the consumption of fuel
  • A strong, bitter smell from the exhaust.
  • Change to the engine note

If the regeneration fails due to an insufficient motorcycle, any extra fuel that is injected into the cylinders will not be burned and will flow into the sump. The oil quality will deteriorate and the level of oil will increase. Most DPF-equipped engines will have an oil quality/viscosity monitor, however, it is imperative to be sure the oil level does not increase above the level that is indicated on the dipstick as diesel engines run without oil if the levels are excessive, frequently to the point of destruction.

If you ignore the diesel particulate filter warning light and continue driving in a fairly slow, stop-and-start style, soot will continue to build up until it reaches 75%. At that point, you can expect to see additional dashboard warning light lights come on. At this point driving at a high speed will not suffice to clean the filter. You’ll have to take the vehicle to a mechanic to undergo “forced” regeneration.

Forced regeneration

The forceful regeneration process is required when “active” regeneration criteria have not been fulfilled and soot levels within the DPF have increased by about 70 70%. If left unattended, the load of soot continues to build up. At this point, a diagnostic tool must be used to trigger regeneration. If you are at around 85% soot loading, regeneration will not be able to more be accomplished on the vehicle and you will have to remove all DPF to be cleaned or replaced.