Regeneration of diesel particulate filter using nonthermal plasma without catalyst

The regulation for the automotive diesel engine emission becomes severe every year, and it is difficult to meet the requirement only by the combustion improvement techniques in the near future. More effective post-processing technology is desired, especially on particulate matter (PM), such as carbon soots. Although the use of ceramic diesel particulate filter (DPF) is now a leading technology for PM removal, the problem exists on the soot removal or regeneration at low temperature, especially at the cold start. In the study, a regeneration of DPF with collected PM was investigated using the low temperature atmospheric pressure nonthermal plasma. The method is to use the NO/sub 2/ and radicals induced by the plasma reactor to burn carbon soots deposited on DPF. First, three types of DPF plasma reactors were made and the performances on the conversion of NO to NO/sub 2/ were evaluated on various conditions. Next, a regeneration experiment was carried out using a barrier type pulse corona plasma reactor. As a result, it was confirmed that the pressure difference decreased only when the plasma was turned on and the regeneration of DPF was realized at less than 250/spl deg/C.