Particulate filter DPF

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Diesel particulate filters operate by trapping soot particles from the engine exhaust, preventing them from reaching the environment. Unlike a catalytic converter which is designed to reduce gas-phase emissions flowing through the catalyst, the particulate filter is designed to trap and retain the solid particles until the particles can be oxidized or burned in the DPF itself. Understanding the Differences Between Ash and Soot Ash and soot are fundamentally different materials, but both accumulate in the DPF. Removing each of these materials from the DPF requires completely different processes. Soot is normally removed from the DPF through regeneration on the vehicle, which burns off the soot, leaving the incombustible ash behind. Ash, on the other hand, by definition is incombustible and must be cleaned from the DPF. Ash Sources and Chemical Composition For most DPFs in on-highway applications with a properly functioning engine, there is only one major source of ash – engine lubricant oil. Specifically, it is only certain additives in the oil that contribute to ash in the DPF. Other sources of ash, which contribute to a lesser extent, include certain elements in the fuel, engine wear metals, exhaust system corrosion products, and ambient sources.