Particulate Filter Diesel

Particulate Filter Diesel

A particulate diesel filter is a device that is used to take-out diesel particulates or soot from the combustion of diesel engine. This device normally captures around 85% or more from the diesel particulates and in other cases can achieve 100% in removing soot. Some particulate filter diesels are designed to be used once, when it is already clogged with ashes, it needs to be replaced. Others are made to burn the excess particulate that accumulates through the use of passive catalyst or by active procedures such as burning of fuels which in turn heats the filter to a required combustion temperature. In this case, the engine is programmed to move when the filter is full in such a way that it heightens exhaust temperature or creates maximum amounts of NO2 to oxidize the ashes. This process is called filter regeneration. This regeneration process is seldom achieved in city streets where vehicles are being driven in low speeds as required by traffic rules. To attain regeneration process, urban vehicles need periodic trips to achieve higher speeds that will clean out the particulate filter diesel. To maintain the optimal functionality of particulate filter diesel, cleaning it in periodic interval is required. However, proper care should be practiced when cleaning particulate filter diesel as it is also prone to damage.

Particulate Filter Diesel – Two Common Types

Silicon Carbide Wall Flow Filters

This is the 2nd commonly used particulate filter diesel. Compared to cordierite, it requires higher melting temperature (2700°C) but it has a more stable thermal temperature making it easy to be packaged. Standard silicon carbide particulate filter diesel has a core made of one piece, while bigger cores are designed in segments that are separated by cement that will absorb the heat generated by the core, not the package. This type of particulate filter diesel is more expensive than its cordierite counterpart; however they are produced in same sizes so that one can be replaced by another.

Ceramic Fiber Filters

This type of particulate filter diesel is made from fibrous ceramic materials that are mixed together to create a porous material. This porous material can be molded in any desired shape and can be made into different applications. The porosity can be regulated to create high flowing energy, with lower or higher efficiency volume filtration. The filters that are more fibrous are more efficient in generating lower back pressure compared to filters with wall flow design. This type of particulate filter diesel trap almost all the carbon particulates, including very fine particulates measuring less than 100 nanometers (nm) in diameter. It can eliminate 99% particles over a bigger range of engine operating systems.  However since the soot continuously pass in and out of the filter, eventually, the soot will block it. In this case, it is needed to “regenerate” the filter by combusting the accumulated particulate on a periodic basis.  When soot particulates are burnt, it forms carbon dioxide and water in small amount since it is less than 0.05% of the C02 given off by the engine.

Whatever kind of particulate filter diesel your vehicle has is necessary to regularly clean the filter. Both types of particulate filter diesel give instruction to the driver when it might cause issue or damage to the engine.

 

Diesel Particulates

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