Diesel Particulate Filters
What is a diesel particulate filter and why does it matter?
What is a Diesel Particulate Filter (DPF)?
The DPF was introduced in 2009 when it was made a legal requirement for all manufacturers to fit them into new diesel cars. The DPF has one job: to capture soot from your exhaust to help reduce pollution.
But why do you need to know this?
Well, all the soot that gets stored in the DPF needs 'burning off' otherwise it can end up blocking. If it gets blocked, it is up to you to unblock it.
How do you burn it off?
By something called regeneration, of which there are two types; passive and active.
Passive regeneration is when the heat from the exhaust is hot enough to burn off the soot. This heat is typically generated by driving above 40mpg for 10+ minutes, but that can vary depending on things like speed, the car itself, the amount of soot in the filter, etc.
Active regeneration is there in case the exhaust doesn't reach a high enough temperature. If a filter reaches a certain capacity or you've covered a certain number of miles, some cars will inject fuel into the exhaust to increase the temperature.
However, problems can occur if the journey is not long enough and the process hasn't concluded. If this happens, a warning light usually displays and it is advised you take your car for that drive until the light goes off.
What happens if the regeneration doesn't work?
In the rare event that the drive has not put it right, you can take your car into a garage, where they will remove the excess soot. This starts from around £80 and is pretty much guaranteed to fix it.
What happens if the DPF filter gets blocked?
If you haven't managed to clear it yourself or take it to a garage, you might end up needing a new DPF...which isn't cheap. Depending on the car, this can start anywhere from £1,000 all the way up to £4,000+ and is not covered under maintenance or warranty, so it'll be on you to pay.
If you're unsure about if a diesel is right for you, get in touch and we can have a chat.
Here are our most frequently asked questions when it comes to Diesel Particulate Filters.
What is a DPF and why is it important?
A DPF captures and stores exhaust soot to reduce emissions from diesel engines. It's crucial for meeting environmental regulations and improving air quality.
How does a DPF work?
The DPF traps soot particles as they pass through the exhaust system and periodically burns them off in a process called regeneration, keeping the filter clear and functioning.
What causes DPF blockage?
Short trips where the engine doesn't reach optimal temperature can prevent the DPF from regenerating, leading to blockages.
How can I maintain my DPF?
Regular longer drives at higher speeds can help the DPF regenerate properly. It's also important to keep up with vehicle maintenance schedules.
What happens if my DPF is removed or fails?
Removing or tampering with the DPF is illegal and can result in MOT failure. A malfunctioning DPF can lead to reduced performance and potentially costly repairs.
Can a DPF be cleaned or does it need replacement?
DPFs can often be cleaned, which is a more cost-effective solution than replacement. However, in cases of severe blockage, replacement might be necessary.
What is DPF regeneration and how is it triggered?
Regeneration is the process of burning off accumulated soot. It can be passive (occurs naturally during long drives) or active (initiated by the vehicle's ECU under specific conditions).
How do I know if my DPF is blocked?
Warning lights on the dashboard, decreased fuel efficiency, and reduced engine performance can indicate a blocked DPF.
Does driving style affect DPF longevity?
Yes, frequent short journeys at low speeds can prevent proper DPF regeneration, leading to quicker blockage and reduced lifespan.
Are there any additives I can use to help maintain my DPF?
Some fuel additives claim to assist in keeping the DPF clear by lowering the temperature at which soot burns off, but it's essential to use them cautiously and follow manufacturer recommendations.
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