Study On Influence Factors Of DPF Off-line Regeneration By Non-Thermal Plasma Technology

Diesel particulate filter（DPF） is considered to be one of the most effective means to reduce emission of particulate matter from diesel engine. However, the increment of captured particulate matter increases the backpressure of DPF. The normal operation of the diesel engine will be affected when the backpressure of DPF reaches a certain degree. Hence, the technical challenge of the DPF technology lies in its regeneration. The promotion of traditional regeneration methods is restricted in China, because of their own shortcomings. In recent years,non-thermal plasma（NTP） technology has been one of the focuses of DPF regeneration research. A DPF regeneration system based on NTP technology was built up and the influence factors of DPF off-line regeneration by NTP technology were studied. The main researches are as follows:（1）By using a DPF regeneration system based on NTP technology, an experiment on the regeneration of diesel particulate filter was carried out, where oxygen as the gas source. The effect of engine load on the oxidation of PM and DPF regeneration was investigated by observing the variation of carbon oxides during regeneration process. Results show that, active substance O3 and O was generated through the discharge reaction of NTP reactor and played a leading role in the decomposition of PM. Hence, DPF can be regenerated effectively. Active substance has a stronger ability to decompose PM produced by diesel running at medium load.（2）By using a DPF regeneration system based on NTP technology and three different oxygen flow control methods, an experimental study of the regeneration of diesel particulate filter was conducted with oxygen as the gas source.Three methods used the same total amount of oxygen. The effect of oxygen flow control methods on the oxidation of PM and DPF regeneration was investigated by observing the variation of carbon oxides during regeneration process. The results showed that the regenerative effect of DPF by using variable flow control method was better than that by using constant flow control method. The best regenerative effect of DPF can be got by making oxygen flow decrease with the passage of experimental time.（3） By using a DPF regeneration system based on NTP technology, an experimental research on the regeneration of diesel particulate filter was carried out with air as the gas source. The effect of air flow rate on DPF regeneration and the variation of DPF inner temperature during regeneration process was investigated. The results showed that activesubstance O3 and NO₂ was generated through the discharge reaction of NTP reactor and played a leading role in the decomposition of PM. With the increase of air flow rate, the mass of decomposed PM increased and the mass of decomposed PM per liter decreased. During DPF regeneration process, the axial measuring points’ temperature increased in the air flow direction and the same measuring points’ temperature decreased with the increasing of air flow rate.