Diesel Particulate Filter is a device installed in a diesel vehicle exhaust system that reduces particulate matter (PM) in the exhaust by filtration.
Diesel Particulate Filter captures particles, such as diffusion sedimentation, inertial deposition, or linear interception, through a mixture of surface and interior filtration devices. DPF can effectively purify the 70%–90% particles in the exhaust, which is one of the most effective and direct methods for purifying diesel particulate matter, which has been commercialized internationally.
There are two major upgrade scenarios, one of which is through the use of selective catalytic reduction (SCR) technology, the nitrogen oxides in the tail gas were treated with urea solution, and one of them was EGR (Exhaust Gas Recirculation) technology which was processed by particulate traps (DPF) or particulate catalytic converters (DOC) for combustion-generated particles.
DPF technology is relatively complex, the chemical reaction temperature is high, the performance is not stable. In addition, DPF requires that the fuel contain less than 50PPM of sulphur. With the increase of working time, the internal particulate matter (PM) increases, which leads to the increase of exhaust backpressure, which will affect the economic power of diesel engine. To remove the PM on the cartridge is called DPF regeneration, the biggest challenge that DPF faces is the regeneration problem.
By combining DOC/DPF and SCR, their passive regeneration and active regeneration can produce more control over the oxidation and cleaning filters, thereby removing more than 90% of the particulate matter. After the system optimization and matching with the engine, the DOC/DPF+SCR processing system will effectively deal with the particulate matter and nitrogen oxides at the same time and reduce it greatly, thus satisfying the higher emission requirements.
To meet 2010 emissions regulations in Europe 6 or the United States, reprocessing systems will be more complex, with the need to integrate an oxidation catalyst (DOC), Diesel particulate filter (DPF), selective catalytic reduction (SCR), etc. into one to control emissions.