How The DPF(Diesel Particulate Filter) Works

The Diesel Particulate Filter (DPF) is an important device used to reduce the emission of particulate matter (PM) in the exhaust gas of diesel vehicles. Its internal structure is a ceramic carrier with parallel axial honeycomb holes all over the interior, and the holes are adjacent to each other, but only one of the two holes is open at the entrance. The other is only open at the exit, using this zigzag hole to keep particles on the carrier and achieve filtration effect. The following is a detailed analysis of the working principle of DPF:

How it works:

Capture particulate matter:

When diesel engines burn fuel, they produce particulate matter, including PM10 (inhalable particulate matter) and PM2.5 (fine particulate matter).

DPF traps these particles through its internal unit structure, which is usually made of ceramic or metal materials and has a microporous structure. These pores can trap particles while allowing exhaust gases to pass through.

Filter particulate matter:

Over time, the particles captured in the DPF accumulate.

The unit structure inside the DPF effectively filters out particulate matter in the exhaust through its micropore structure, thereby reducing PM emissions in the exhaust.

Combustion particulate matter (regeneration process) :

Due to the accumulation of particulate matter, the filtration efficiency of DPF will gradually decrease. In order to recover its filtration performance, a regeneration process is required.

The regeneration process usually restores the filtration efficiency of the DPF by increasing the internal temperature of the DPF so that the accumulated particles reach the combustion temperature and burn off. This can be achieved through either active or passive regeneration.

Active regeneration:

When particulate matter accumulates in the DPF to a certain extent, the system triggers an active regeneration process.

In the process of active regeneration, the engine control unit will adjust the operating parameters of the engine, such as increasing the amount of fuel injection, adjusting the ignition time, etc., to increase the temperature of the exhaust gas.

At the same time, high temperatures may be generated by injecting additional fuel into the exhaust pipe (such as exhaust tail pipe HC injection technology) or by utilizing the DOC (Diesel Oxidation Catalyst) in the reprocessing system to burn the particles in the DPF.

During the regeneration process, the temperature of the DPF will increase, so special care needs to be taken to avoid operating near hot areas.

Passive regeneration:

Passive regeneration uses the heat generated during the normal operation of the engine to achieve DPF regeneration.

When the engine is operating at high speed or high load, the temperature of the exhaust gas naturally increases, which triggers the combustion of particles in the DPF.

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