Service regeneration – If pressure continues to increase, usually due to the previous efforts failing due to short stop start driving not conducive to high temperatures, the final attempt involves a technician using a scan tool to manually command the engine management computer to employ aggressive strategies at a standstill to burn the particulates.Heating coils or microwave energy to increase the exhaust temperature.Use of a fuel borne catalyst to reduce soot burn-out temperature – commonly used by BMW and MINI in the form of EOLYS additive.A fuel burner after the turbo to increase the exhaust temperature.Increasing exhaust temperature through late fuel injection or injection during the exhaust stroke.Strategies used my manufacturers include – Active regeneration – If pressure continues to build in the DPF over normal driving, the computer will take a variety of steps to raise temperatures high enough to burn the particles.During normal engine operation under certain conditions and usually aided by mounting the DPF close to the engine and in conjunction with a catalyst, there is enough heat built up in the DPF to burn the particles without any extra action taken by the computer. Passive regeneration – This is the best case scenario.The 3 main regeneration strategies used by all cars with DPF’s are – The main particle caught is soot (black carbon) – soot is the result of partially burnt diesel – the black stuff you often see bellowing out of diesel exhaust at high load.Ī differential pressure sensor monitors the pressure before and after the DPF, creating a reading so the car’s engine management computer knows what level of blockage the DPF is at so it can use its regeneration strategies to burn the particles off to a gas which will pass through the walls of the DPF and out the exhaust, clearing the filter and ready to start the process all over again. Although diesel engines are light years more refined than those of previous decades, to meet ever tightening emissions regulations car makers have to employ several different technologies – one of these is a Diesel Particulate Filter (DPF).Ī DPF’s main function is to catch particles, which can later be burnt at extremely high temperatures, resulting in lower emissions.

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