Diesel Particulate Filter: What is it, and how does it work?

Published at

A Diesel Particulate Filter (DPF) is a device designed to remove soot and solid particles from the exhaust gases of a diesel engine.

In today's article, we will shed light on the function of the diesel particulate filter, also known as the FAP filter, how this device got into cars and its lifespan.


How did the Diesel Particulate Filter get into cars?

With the advent of the Euro 5 emission standard, strict rules were created to comply with the amount of emissions of unburned solid parts in the exhaust gases. That's why manufacturers have started installing diesel particulate filters called DPF or FAP filters in all new diesel cars.

With this emission standard, you won't find a single new diesel car that doesn't have this filter. The exceptions could only be found among cars made for countries outside the European Union where strict emission standards do not apply.

DPF Warning Light - What to do if it lights up?

As already said, a diesel particulate filter (DPF/FAP filter) is a device that removes carcinogenic and small dust particles from the exhaust gases of cars with a diesel engine. The filter captures solid particles and finally burns them to clean itself.

A lit DPF warning light alerts the driver to ongoing cleaning or regeneration of the diesel particulate filter. You should not turn off the car in this case. Regeneration takes place by injecting fuel into the diesel particulate filter during engine operation while keeping the engine at a steady pace between 2000 and 2600 rpm is recommended.

DPF filter

Simply put, swift driving outside the city or on the highway will benefit in this case. The diesel particulate filter warning light most often appears if the vehicle is used mainly in the city for short trips - these do not benefit the filter. However, if the warning light stays on after regeneration (approx. 15 minutes), it may indicate a malfunction of the diesel particulate filter.

Cleaning of the Diesel Particulate Filter

Other ways of cleaning the solid particles filter are its disassembly and subsequent rinsing with hot water, using chemicals that dissolve the captured particles, or ultrasonic cleaning. Not every type of filter can be cleaned, so you may have to pay extra for a new one.

The lifespan of the Diesel Particulate Filter

The lifespan of the diesel particulate filter is very dependent on the driving style and the quality of the oil. Cars equipped with a diesel particulate filter require a special type of engine oil that is adjusted precisely for their needs. Sometimes, however, the right oil and driving style does not help, and the filter may fail even before reaching its lifespan range of approximately 80 to 150 thousand km (roughly 50 to 100 thousand miles).

DPF filter

Many motorists criticize this so-called "exhaust pipe blockage," which reduces engine performance and increases consumption. Some people remove it from their cars since cars with a dismantled particulate filter could sometimes pass the emission control without major problems. However, we don't recommend doing that.