What is a DPF?
DPF is an abbreviation for Diesel Particulate Filter. It is also known as a FAP or filtre à particules on some French vehicles.
The DPF is a Particle Filter specially designed for modern diesel engines to reduce the pollution emitted by diesel vehicles by filtering the solid soot particles contained in the exhaust gases. It is similar to and used in conjunction with a Catalytic Converter, which can also be found on many petrol engines which lowers emissions.
The exhaust gases flow through the DPF where approx 80%-90% off the soot particles are extracted and cling to the Honeycomb like Brick Element of the DPF, where they wait til the vehicle produces a regeneration cycle and burns off all or as much of these soot particles as it can. The regeneration cycle is performed by the ECU when the engine is running at high speed and the high exhaust gas temperatures allow it to do so.
The problem with this can be quite apparent to many motorists as a regeneration can only occur when the vehicle is running at speed, which is generally plus 40mph for at least 20 minutes. This is fine for the many motorists who frequent the Motorway on a daily/weekly basis, but for all those that only make urban trips this soon causes problems as the vehicle never performs a normal regeneration cycle.
Once the DPF accumulates particulate matter to approx 70% saturation you will start to notice a lack in power from your vehicle, you will notice fault lights appearing on your dashboard to include the engine management light, dpf symbol and ultimately the glow plug light. When your vehicle gets to this point you should ideally not drive it any further as further damage to your vehicle can occur. When your vehicle reaches this point then a forced regeneration by a garage is required, which will fix the problem temporarily but not indefinitely as if the vehicles driving styles are retained the DPF will eventually fill up again with the soot particles from the exhaust gases.