DIESEL PARTICULATE FILTER (DPF)

The diesel particulate filter (DPF) is an exhaust gas post-treatment system responsible for reducing emissions from diesel vehicles by capturing, storing and subsequently eliminating soot particles resulting from the combustion process.

This soot particle removal action is known as particulate filter regeneration. This process is carried out by increasing the temperature of the particulate filter (around 600ºC) in order to burn the soot particles accumulated in it and prevent them from being eliminated by the exhaust pipe. Also avoiding, in this way, observing the well-known black smoke that used to appear from the exhaust pipes of older diesel vehicles.

There are two types of regenerations for the particulate filter: active or passive.

Passive regeneration is achieved by driving the vehicle at high speeds on a motorway (around 2500 rpm). These high speeds allow the exhaust temperature to rise to higher levels than we can achieve driving around town and consequently allows the soot to be burned off.

Driving at these high speeds for about 30-50 min is recommended to help clean the filters. In the event that the vehicle does not inform us that regeneration is taking place, we must also sharpen our senses so as not to interrupt the regeneration.

However, as this fact is not always possible to do regularly, there is another type of regeneration possible.

In active regeneration, extra fuel is automatically injected in order to reach the necessary temperature to activate the filter and burn soot particles. This fact usually happens if the filter capacity exceeds approximately 45% of its capacity.

In these cases, it may happen that the process starts in too short a path and that the filter does not manage to regenerate completely during it. In these cases, it is very possible that the cycle can be completed by driving for a few more minutes at a speed higher than 6-7 km/h.

We can tell if active regeneration is taking place, so as not to stop the vehicle at that moment, by the following factors: changes in engine noise, fans running, a slight increase in fuel consumption, automatic deactivation of the start/stop system, increased idle speed, or a pungent odor of the exhaust pipe.