Carbon particulate matter incineration in diesel engine emissions using indirect nonthermal plasma processing

One of the promising applications of nonthermal plasma (NTP) for environmental cleanup technology is low-temperature oxidation or incineration of carbon particulate matter (PM) in diesel engine emissions. In this process, NO₂ and activated radical species induced by NTP can incinerate carbon PM trapped by a diesel particulate filter (DPF) at low temperature (< 300 °C). In the present study, an experiment was carried out on indirect NTP DPF regeneration for real diesel engine emissions comprising CO₂ of several per cent, hydrocarbons of several hundreds of ppm and moisture of several tens of percentages. It was confirmed that DPF regeneration is possible for a real diesel emission at a low temperature of 280 °C. The removal energy efficiency was estimated to be 0.82 g/kW h. This electric power range is sufficient to meet the recently proposed long-term national regulation for diesel automobiles in Japan.