Diesel Particulate Filters (more commonly known as DPF’s) are widely used on modern day diesel vehicles. They target the sooty particles that diesel engines produce. These can penetrate deep into the lungs and are seen as being responsible for an increase in heart and lung problems. With the introduction of Euro 6 Emissions Standards in 2015, it would appear that for now, Diesel Particulate Filters are here to stay.
Here is a brief explanation of what they do and how they work.
The Diesel Particulate Filter has a honeycombed interior, similar to a catalytic converter, which is made of silicon carbide. This is inside the steel surround that you can see.
This honeycombed centre is designed to trap the particles of soot which have not been burned off or cleared by the additive.
Some Diesel Particulate filters use an additive which enables them to burn off the soot particles, and some are fitted closer to the engine which means that the exhaust gasses are hot enough to burn off the carbon soot particles.
When the filter is full and no more soot particles can be trapped the DPF needs to undergo a regeneration process, which converts the soot into a small amount of ash. There are two types or regeneration processes which take place in ordinary usage.
Passive regeneration
The most frequent kind of regeneration, passive regeneration should automatically take place when the vehicle is driven at higher revs for a longer period (for example if being used on a motorway for a reasonable distance). This enables the exhaust temperature to reach a level which can burn off the soot for a sustained period. There are however many vehicles which do not undergo these kind of trips frequently enough for this to happen as often as is needed.
Active regeneration
If the vehicle doesn’t make these journeys often enough in regular use it is advisable to deliberately drive the vehicle in this way to actively try to start regeneration and clear the warning light.
Sometimes the filter will not be given the chance to undergo either of these regeneration processes, and the filter will become too blocked for a regeneration to take place. At this point the vehicle will need to undergo some type of professional service.
“A Blocked DPF?!”
This phrase is being heard more and more around the garages of England. Resulting in costly diagnostic and repair procedures. The mere thought of buying a used car with a DPF has been known to cast fear into the minds of some of our customers.
Modern diesel engine vehicles however do have their benefits, one of which is the extraordinary fuel efficiency the vehicles are capable of. If you already own a vehicle with a DPF, here are 5 tips to prolong the lifespan and save you money.
- Use the correct oil! – Not using the correct oil specified for your engine can significantly add to the soot build up in the DPF. These engines usually use Low Ash oil; always consult your manufacturer’s handbook.
- Motorway once a month – Most DPF systems attempt a passive regeneration approximately every 400 miles. Remember; over 40mph, over 2,000rpm for around 15-20 minutes.
- Avoid stop/start short distance journeys- if the majority of your driving is short distance, slow driving – a diesel engine car may not be for you!
- Various over the counter fuel treatments are available; these vary in quality however some can be very effective. These should be applied periodically to keep the filters soot free. Here at Motor Marque we sell a good quality treatment and we are happy to advise you on how and when to use it.
- Have your car serviced regularly- as mentioned earlier, oil specification is very important. As the age and mileage of your car increases, the more frequently the oil is changed, the better!
Using these guidelines you can help protect yourself from costly issues, however you should choose wisely when searching for a used diesel, and bear in mind that some manufacturers have pre-set replacement intervals, meaning that regardless of how well the system has been cared for an expensive replacement could be imminent !