How to clean a Diesel Particulate Filter while driving ?

Every year, the French drive an average of 13,000 kilometres. That's relatively little. A good proportion of them - perhaps you - use their cars in urban areas. There's nothing wrong with that. But if your car runs on diesel and has a diesel particulate filter, the risk of clogging becomes very real. Fortunately, there's a simple way of cleaning a diesel particulate filter ! The solution is to drive your car in a slightly higher gear. Here are the instructions for prolonging the life of your DPF.

How does a DPF work ?

A diesel particulate filter works in two stages. Firstly, it filters out fine particles and collects them. These particles clump together to form a thick layer around the filter, which can eventually clog it.

Secondly, the regeneration stage burns this layer of fine particles to destroy them. In this way, the DPF can once again collect fine particles and start new recycling cycles. However, for regeneration to take place, the vehicle must be hot enough to reach almost 600°C inside the diesel particulate filter. Without this, the DPF regeneration cycles cannot start. Clogging then becomes inevitable over time. Are you wondering how long it takes to regenerate the DPF ? On average, soot is destroyed once every 2 to 3 weeks, and the process takes just 3 to 5 minutes. When you're driving, you won't really feel any difference when the procedure is started, but you will notice that instantaneous fuel consumption increases during the operation and that smoke may be visible at the tailpipe.

Why does the DPF clog up ?

The purpose of the diesel particulate filter is to collect fine particles in a structure covered with a thin layer of rare metals, called the monolith. Over time, these particles increase in volume and can clog the honeycomb structure that makes up the monolith inside the diesel particulate filter. To counter this, regeneration cycles are carried out automatically as soon as the engine reaches a sufficient temperature, generally around 600°C. However, a car that is mainly used for short urban journeys will not be able to reach the minimum temperature required to launch a regeneration cycle. This can lead to progressive clogging of the DPF. It is often possible to force a regeneration cycle to be carried out in a garage, but there's nothing like a conventional, regular elimination.

How can you tell if the DPF is clogged ?

There are several signs that your car's diesel particulate filter may be clogged. Here are the most common symptoms. They may all be present, or just a few:

• Loss of power: the engine has lost its ability to accelerate and recover. In practice, this is more difficult to detect because it is quite gradual;

• Emission warning light on: this is the most frequent symptom. When it comes on, it's important to have your car checked by a garage to get more information;

• Downgraded mode: the engine no longer delivers its power, jerks and operates in downgraded mode due to clogging;

• Excess fuel consumption: your car's fuel consumption increases quite significantly.

How do you clean a DPF while driving ?

To clean the diesel particulate filter while driving, you need to drive. Logical, you might say ! Yes, but not just any old way. The motorway is ideal for this exercise, but simple roads will do.

Keep the engine speed at a minimum of 3,000 rpm. This is because the temperature of the DPF is indirectly correlated with how hot the engine is. If your car has an automatic gearbox, change gears in manual mode, increasing the number of revolutions. However, there's no need to go as far as the rev limiter, as that won't do any good. Drive in this mode for at least 30 minutes. This will trigger a regeneration cycle and your DPF will be cleaned. Additives can also help to promote cycles by slightly lowering the temperature required for regeneration to take place, thereby optimising the life of the anti-pollution devices.

This operation should be repeated regularly, ideally once every fortnight. Whether it's a BMW diesel particulate filter or a Peugeot DPF, the operation remains exactly the same. To go one step further, we've compiled 10 unbeatable tips for extending the life of your DPF.

Do you want to know if your catalytic converter is bad ? Do you want to know if your DPF is clogged ?

Don't forget !

To make your diesel particulate filter last as long as possible, you need to carry out these DPF regeneration cycles regularly. However, this method will not work miracles. If the DPF is permanently damaged, i.e. clogged, it will have to be replaced.

If in doubt, ask a car dealer or a car centre for advice. The latter will be able to test whether or not the anti-pollution device is damaged. What's more, starting a regeneration cycle before taking the roadworthiness test is a good way of ensuring good results before the anti-pollution test. Think about it next time !

Image sources:
Karolina Osinska / Author: duallogic / Licence ID: 9BKJGDFATV - elements.envato.com