What Are Diesel Particulate Filters?
Today, there are much-increased regulations around the emissions of particulate matter. Improved EU legislation dating from 2016 significantly tightened up the rules around particulate matter present in exhaust emissions, and that has led to the widespread adoption of diesel particulate filters (DPF).
The filter works by trapping the vast majority of soot that results from diesel engine combustion. Instead of this soot particulate matter releasing into the atmosphere, a diesel particulate filter contains it and ensures the vehicle at hand meets EU emissions requirements.
While diesel particulate filters do significantly reduce emissions levels, but the technology may not be suitable for vehicles used in a predominantly urban environment. In these cases, it may be best to choose an alternative – petrol, hybrid, electric, or other – or specifically seek out a vehicle with a self-heating diesel particulate filter.
Diesel Particulate Filter Regeneration
At a certain point, diesel particulate filters need to get rid of the soot they capture to function at the optimum level – and this process is known as regeneration.
In order to reach the high temperatures required for the DPF to turn the captured soot into a small amount of inert ash, the driver of the vehicle needs to drive at about 50mph or more for, at a minimum, twenty minutes. This will enable the filter to regenerate and re-attain top performance.
If the regeneration process goes ignored, the result is a build-up of soot in the DPF and, ultimately, this will cause damage to the filter itself. Nearly all modern vehicles with DPF carry an onboard warning light that will inform the driver that regeneration is overdue. When this happens, all the driver needs to do is ensure they undertake the regeneration driving practices outlined above and the warning light should deactivate.
However, if the driver continues to drive a vehicle without heeding these warning signs, the long-term result is often damage to the vehicle’s engine. In this case, the vehicle will require professional intervention.
What Are Self-Heating DPF?
While most vehicles carrying a DPF require the regeneration process outlined above, some modern vehicles feature a self-heating DPF.
One form of self-heating DPF involves injecting a small amount of fuel into the filter, which then causes the temperature of the filter to rise and, thus, burns off the soot present. The other form of self-heating DPF uses a heater built into the filter to raise the temperature and achieve the same result.