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FAP/DPF

At EXTREME CAR SERVICE
LTD we offer removal of diesel particulate filters


Modern diesel vehicles are fitted with diesel particulate filters that filter the exhaust gas. However, many drivers decide to take them off. Find out why! Diesel particulate filters, also know by the abreviated names DPF or French FAP (filtre a particules) are fitted in most modern vehicles with compression - ignition engines. Their role is to stop carbon black particles from the exhaust gas. They are one of the most difficult pollutants produced by diesel engines. DPF have been around for more than 30 years but up to the end of 1990's they were only used in commercial vehicles. Introduction of DPF eliminated emission of the black fumes characteristic in older diesel engines. Currently they are also fitted by modern car producers to keep up with the raising standards in legislation for exhaust gas emissions.

Structure and operation

DPF is fitted in the exhaust system of your vehicle. On the outside it looks like a muffler or a catalytic converter. It is filled with a structure consisting of many walls (which looks a bit like the air filter). They are made of porous metal, ceramics or, less often, a special type of paper. This is where the carbon black particles stop. Currently, almost every car producer offers cars with engines fitted with this type of device. The DPF filters have therefore become a bit of a nightmare for drivers. They typically get blocked and loose their effectiveness. When that happens, a light comes on your dash board. The engine starts loosing power and goes into safe mode. Producers have predicted this and worked out a process of self cleaning for the filers during which the excess carbon black particles are burnt out. There are two most widely used methods. Burning out through a temporary change in the pace of running the engine, or through adding a special fluid to the fuel.

Burning out is troublesome.


The first method is most popular, used for example by the German car makers. To carry it out the engine should run at higher rpm for some time whilst the speed should not exceed about 80 km/h and it should stay the same. The engine emits more carbon dioxide, which gradually burns out the carbon black particles. In the second method special fluid is added to the fuel. It causes the temperature of the exhaust gas to rise and burn the excess carbon black particles in the DPF filter. This method is more widely used in French vehicles. For both methods to be effective you need to drive the distance of about 20 - 30 km. And this is where the trouble starts. If your light comes on while you're driving long distance you can probably manage to drive such distance in the way described, but what if you only drive around town? It is virtually impossible to do 20 km at the same speed. In that case blocked filter can cause more serious problems. It can result in you car loosing power and eventually it will mean changing the part, which is not cheap. What is more, a blocked DPF filter badly affects the fuel system. In extreme circumstances it can lead to increase in oil pressure and decrease lubrication. It can even result in engine seizure.

What to use instead of DPF?


For the above reasons more and more drivers want to remove the PDF filter. You can't do it if your car is still on warranty and taking it off at home wouldn't be advisable because it is connected with the computer controlling the engine through sensors. It is therefore necessary to swap the filter for a piece of equipment called the emulator or to install a new program on the on board computer, which will account for the lack of DPF filter. Emulator is a small electronic piece of equipment, which sends signals to the engine controller similar to those sent by the sensors monitoring DPF. The other method is based on installing a special program into the engine controller, which will account for the lack of PDF filter. The price for this method is similar to the price of installing the emulator (including removal of the DPF filter). Experience tells us that installing an emulator is better. It is an external piece of equipment, which can always be taken off if you decided to go back to using a DPF filter. What is more, it is less invasive into the electronic systems of the vehicle. Installing a new program on the computer controlling the engine carries some restrictions, for example, when your car breaks down and the computer requires reprogramming. In this instance the new software will automatically delete any previous settings. You could also delete settings accidently, for example when a mechanic who wasn't aware of them makes changes.