DPF Diesel Particulate Filter as Catalytic Converter:
With increasing appearance of diesel engine automobile, the particulate from emission, mainly carbon, enhances the pollution to the environment.Regulation for diesel engine, stipulating the particulate in diesel passenger cars emission should meet the criterion: below 2.0g/mile. The diesel particulate filter is able to filter above 80% carbon smoke particulate .For practical application, it would be a great help to solve the problem of air pollution.
If the DPF is coated with precious-metal (such as Pt, Pd and Rh), black smoke with carbon particulate from diesel engine pass through a special tube and enter the filter. The carbon smoke particulate is absorbed to the filter made of metallic fiber felt, when passing the inner dense set and bag-style filter. When particulate absorption reaches some degree, the tail burner would be ignited to burn automatically. In this case, the particulate absorbed been burned out and turned into nontoxic CO2 then discharge. The full device is designed as double room structure, and filtration and recycle are going in different areas, making them non-disturbed. The system can work automatically whatever working condition the engine in. especially made honeycomb ceramic particulate filter, acts as capturing device to the particulate to some extent.
The structure of a diesel particulate filter (DPF) is similar to an autocatalyst, but differs in that at least a portion of the exhust gas is passed through a physical filter. The most commom and well known are wall-flow filters, typically using a ceramic honeycomb substrate of cordierite or silicon carbide. Half of the channels are sealed at the inlet face in a chessboard pattern, and the remaining alternate channels are sealed at the outlet face of the substrate. Exhaust gas cannot pass straight through the device, but instead is forced through the walls between the channels and the particulate matter deposited on the walls.