Diesel Particulate Filter Operational Diagram. Particulate-laden diesel exhaust enters the filter, but because the cell of the filter is capped at the opposite end, the exhaust cannot exit out the cell. Instead the exhaust gases pass through the porous walls of the cell. The particulate is trapped on the cell wall. The exhaust gases exit the filter through the adjacent cell.
Regeneration is the process of burning off the collected particulate by means of oxidation.
The particulate is combusted and these gases are oxidized if there is a catalyst present. If exhaust gases do not exceed the required 380 degrees, which often happens during operation, then an additional component is necessary. In some systems this component is an outside heat source that heats the exhaust gases before they reach the filter, while other systems use catalysts that can lower the regeneration temperature that is necessary to oxidize the particulate. Which components to include in the DPF system depend on both the type of machine that the system is to be installed in and the level of the engine performance. Since there is no mandate for emission control equipment, the market for diesel particulate filters has remained small.