Abstract: A system and method for treating a combustion exhaust stream includes admitting an exhaust stream into a non-thermal plasma reactor having at least one segmented non-thermal plasma element including a plurality of individually energizable electrode segments defining a plurality of corona volumes. In a preferred embodiment, the electrode segments are progressively smaller in size in the exhaust flow direction to provide optimum plasma volume variation. Individually energizable electrodes are selectively activated to effect variable corona volumes for treating an exhaust stream. Additional reactor segments are activated only as needed, such as during periods of high exhaust flow, for efficient treatment of the exhaust stream so as to maintain optimized high space velocity in the active corona volume. The segmented elements may comprise a variety of shapes. The system and method are particularly suitable for gas pretreatment and downstream diesel particulate filter regeneration.

Abstract: A system for concurrent particulate and NOx control in a combustion exhaust stream includes a particulate filter for trapping particulate matter in the exhaust stream; a non-thermal plasma reactor connected downstream of the particulate filter for further treating the exhaust stream; and a catalytic converter connected downstream of the non-thermal plasma reactor for reducing nitrogen oxides in the plasma treated exhaust stream. The system further includes an ozone generating device associated with but thermally insulated from the non-thermal plasma reactor for generating and discharging ozone to the combustion exhaust stream to create an ozone and NO2 enriched exhaust stream. The ozone and NO2 enriched exhaust stream is fed into the filter to regenerate the filter by oxidizing particulate matter trapped in the filter. The ozone generating device and the non-thermal plasma reactor are connected to a single high voltage power source thereby reducing system complexity and cost.

Abstract: A dielectric barrier discharge non-thermal plasma reactor system and method for treating a combustion exhaust stream includes admitting an exhaust stream into a non-thermal plasma reactor having at least one segmented non-thermal plasma element including a plurality of individually energizable electrodes defining a plurality of corona volumes. In a preferred embodiment, the individually energizable electrodes are progressively smaller in size in the exhaust flow direction to provide optimum plasma volume variation. Individually energizable electrodes are selectively activated to effect variable corona volumes for treating an exhaust stream. Additional electrode segments may be activated such as during periods of high exhaust flow. The segmented elements may comprise a variety of shapes, such as C-shaped elements, I-shaped elements, planar elements, swept-shaped elements, inter-digitized elements prepared from comb-shaped elements.

Abstract: A system and method for treating a combustion exhaust stream includes admitting an exhaust stream into a non-thermal plasma reactor having at least one segmented non-thermal plasma element. The segmented element includes plurality of individually energizable electrode segments defining a plurality of corona volumes. In a preferred embodiment, the electrode segments are progressively smaller in size in the exhaust flow direction to provide optimum plasma volume variation. Individually energizable electrodes are selectively activated to effect variable corona volumes for treating an exhaust stream. Additional reactor segments are activated only as needed, such as during periods of high exhaust flow, for efficient treatment of the exhaust stream so as to maintain optimized high space velocity in the active corona volume.

Abstract: A system and method for treating a combustion exhaust stream includes admitting an exhaust stream into a non-thermal plasma reactor having at least one segmented non-thermal plasma element. The segmented element includes plurality of individually energizable electrode segments defining a plurality of corona volumes. in a preferred embodiment, the electrode segments are progressively smaller in size in the exhaust flow direction to provide optimum plasma volume variation. Individually energizable electrodes are selectively activated to effect variable corona volumes for treating an exhaust stream. Additional reactor segments are activated only as needed, such as during periods of high exhaust flow, for efficient treatment of the exhaust stream so as to maintain optimized high space velocity in the active corona volume.

Abstract: A procedure has been proposed for diagnosing operability of a catalytic treatment device for catalytically treating internal combustion engine exhaust gas, by determining whether the catalytic treatment device reaches a light-off operating condition within a short period of time following an engine coldstart operation. When catalytic converter temperature reaches a temperature level associated, for an operable catalytic converter, with light-off, the operating efficiency of the converter is sampled and, if persistently below an acceptable operating efficiency over a number of coldstart operations, a deterioration in the converter is stored and indicated.