Inside Your Car 9 October 2024

DPF Burn: What is it and why do it?

Diesel vehicles have had lots of improvements over the years in an effort to make them more efficient and kinder to the environment. One of the major updates has been to include a DPF, or Diesel Particulate Filter, in diesel engines as standard.

For the DPF to work efficiently, diesel drivers need to regularly perform a DPF burn. So what actually is a DPF burn, and what do you do when your DPF burn light shows up on the dashboard? Let’s take a look at what you need to know.

What is a DPF burn?

A DPF burn, also known as a DPF regeneration, is an important process in the maintenance of modern diesel vehicles.

The DPF is a relatively new component that’s designed to capture and store exhaust soot in order to reduce emissions from diesel engines. However, the filter can only hold a certain amount of soot before it needs to be cleaned. This cleaning process is known as a DPF burn.

During a DPF burn, this built-up soot in the filter is burnt off at high temperatures, leaving behind a small residue of ash. This process helps maintain engine performance, prevents damage and ensures the car meets environmental compliance standards.

How does a DPF burn work?

A DPF burn is a straightforward process, which the car generally initiates on its own. Here’s a quick rundown of what happens:

Detection of a full filter: The first step is detecting that the filter is getting full. Modern diesel cars are smart enough to know when the DPF is about 45-50% full of soot. This is usually when it's time for a clean-up.
Heating up: To clean the DPF, the soot trapped inside needs to be burnt off. The filter has to get very hot—we're talking about temperatures around 600°C—to turn the soot to ash.
Burning the soot: There are two ways this burning process can happen:
- Passive Regeneration: This happens during long drives at high speeds, like on a motorway. The heat from the engine during these drives is usually enough to burn off the soot naturally.
- Active Regeneration: If you don't often drive long distances at high speeds, the car changes the way the engine runs for a short period to increase the exhaust temperature and start the burning process.
Cleaning the ash: The ash will eventually need to be cleaned out, but much less frequently than the soot needs to be burnt off.
Back to normal: Once the DPF burn is complete, the filter is clean, and the car goes back to its normal way of running.

Why should you do a DPF burn off?

Performing a DPF burn is necessary for many reasons:

Maintaining engine performance: A clogged DPF can reduce the performance of your diesel engine.
Preventing damage: The filter can become excessively clogged, leading to damage to other parts of the engine.
Environmental compliance: A well-maintained DPF ensures that your vehicle meets the emission standards set by environmental regulatory bodies.
Cost efficiency: Regular DPF burns can prevent more costly repairs or replacements.

How long does a DPF burn take?

The time it takes for a DPF burn to be carried out can vary. Passive regeneration occurs automatically when you drive at high speeds for a long period, such as on motorways. This typically occurs over a longer period, often without the driver noticing.

With active regeneration, the vehicle increases the exhaust temperature to burn off the soot. It usually takes about 10 to 30 minutes, however this process can be interrupted if you slow down, stop, or turn off the engine during this time.

How to do a DPF burn

Wondering how to do DPF burn off? While the process often occurs automatically, there are times when you might need to initiate or support the regeneration process. Here’s how to do a manual DPF burn:

Check the dashboard: Look for any DPF-related warning lights or messages.
Drive at higher speeds: If passive regeneration is required, drive your vehicle at a steady speed on a motorway for at least 20-30 minutes. Frequent stopping and starting can interrupt the process.
Avoid short journeys: If possible, avoid short journeys where the engine doesn't reach high temperatures.
Check the manual: Some vehicles have specific instructions for initiating a DPF burn.

Once you've completed a DPF burn, it's important to continue monitoring your vehicle for any signs of blockage. Regular maintenance can also help in preventing issues.

Can I turn my car off during a DPF burn?

High temperatures are needed to carry out a DPF burn, which can only be achieved when the engine is running. As a result, turning off the engine would halt the entire process. If the DPF burn is interrupted, the regeneration process may not be completed, leaving the filter partially clogged. This can lead to reduced engine performance and increased fuel consumption.

How often should your car do a DPF burn?

A DPF burn typically occurs every 30-40,000 km, but this can vary based on driving habits. If you frequently drive on motorways or for longer distances at higher speeds, your car will naturally undergo passive regeneration more often. On the other hand, if you use your car for shorter trips or regularly drive in stop-start traffic, the DPF will need to be cleaned more often.

Understanding the importance of regular DPF burns is crucial for any diesel vehicle owner. It ensures your vehicle runs efficiently and plays a role in reducing emissions and protecting the environment.

At mycar, we offer services tailored specifically for diesel vehicles. Whether it's routine maintenance, addressing DPF warning lights, or conducting thorough checks and repairs, our skilled technicians are equipped to handle it all.

Book your diesel service today and experience the difference expert care can make for your diesel vehicle.