DPF

The residual particulate matter in the exhaust gas needs to be treated with a DPF (diesel particulate matter trap) to ensure that the particulate matter content in the emitted exhaust gas meets the National VI standard. For example, you can use DPF as an air filter to capture particulate matter in exhaust gas.

But after the particulate matter is filtered out, if it is not treated, it will only accumulate more and more in the DPF, and it still needs to be manually cleaned regularly? Of course not, this involves another technology for treating particulate matter in DPF. At present, there are two main methods for treating particulate matter in DPF: active regeneration and passive regeneration.

The ignition point of particulate matter is between 500-600 degrees, which is very high. Active regeneration technology involves injecting fuel into the DPF through the engine's rear injector, where the fuel is burned and the particulate matter is completely removed by the high temperature generated during combustion.

There is also a passive regeneration method, which is relatively complex. After the exhaust gas enters the DPF, some metal substances such as platinum, rhodium, palladium and other rare metals will be attached to the surface of the DPF. By catalyzing the particulate matter, the ignition point of the particulate matter can be reduced, and the exhaust gas residual temperature can be used to burn the particulate matter completely.

These are the two commonly used international methods of handling. However, compared to other methods, active regeneration is relatively simpler and easier to implement. So currently, the majority of post-processing in National VI is still active regeneration of DOC+DPF.