Engine pollution comes mainly from four components -- particulate emissions (PM), hydrocarbons (HCX), nitrogen oxides (NOx) and carbon monoxide (CO). Most of the particulate emissions (soot) are composed of carbon or carbide particles (smaller than 4-20 μm in size).
Particle traps can reduce the soot produced by engines by more than 90%. The captured particulate emissions then burn up during the vehicle's operation. Its working principle is: such as diesel particulate filter spraying metal platinum, rhodium, palladium, diesel engine exhaust containing carbon black smoke, through the pipe into the engine exhaust particulate catcher, through its internal dense set of bag filter, carbon smoke particles adsorption on the metal fiber felt made of filter; When the adsorption amount of particles reaches a certain degree, the burner at the end of the automatic ignition combustion, the adsorption on the above charcoal smoke particles burned, into harmless carbon dioxide emissions. To achieve this, the exhaust post-treatment system uses an electronic control system, a catalytic coating, and a fuel added catalyst (FBC). The fuel - added catalyst contains metals such as cerium, iron and platinum. These materials are added proportionally to the fuel and, with the help of the engine control system, control not only the amount of particulate emissions, but also the amount of pollutants such as hydrocarbons and polluting gases. Regeneration or purging of the trap must be done on a controlled basis to keep the trap from being clogged with soot. At the end of the purification cycle, any residual dust or filter residue will be artificially removed during routine maintenance.
Particle trap can effectively reduce the emission of particulate matter, it first captures the particulate matter in the exhaust gas, and then oxidizes the captured particles, so that the particle trap regeneration. The so-called regeneration of the filter refers to that in the long-term work, the particulate matter in the trap will gradually increase the back pressure of the engine, resulting in a decline in engine performance, so it is necessary to regularly remove the deposited particulate matter and restore the filter performance of the trap. Trapper regeneration has two methods of active regeneration and passive regeneration: active regeneration refers to the use of external energy to improve the temperature of the trap, so that the particle combustion. When the temperature reaches 550 ℃ in the trap, deposition of particles combustion, if not reach a temperature of 550 ℃, too much sediment will jam trap, then you need to use extra energy (such as electric heater, burner or engine operating conditions change) to increase the temperature inside the DPF, make particles combustion. Passive regeneration refers to the use of fuel additives or catalysts to reduce the ignition temperature of particles so that the particles can be ignited at normal engine exhaust temperature. Additives (cerium, iron and strontium) must be added to the fuel in a certain proportion. Too many additives will affect the life of the DOC, but too few will cause delay in regeneration or increase in regeneration temperature.