Abstract:
An NOx reducing exhaust treatment system includes a non-thermal plasma reactor assembly which initiates NOx reduction reactions that are completed by a catalytic converter downstream of the reactor in the system. The reactor assembly includes a monolithic reactor element formed of insulating plates and spacers made of high dielectric material, such as alumina. Some of the plates carry electrodes and connecting conductors which may be painted on with conductive ink and baked on as a surface coating. The electrodes are patterned to provide a distance between the electrodes and the connectors of alternate electrodes that is sufficient to prevent arc over. The plates and spacers form a plurality of thin gas passages each lying between a pair of electrodes, one to be charged with an AC voltage and the other grounded to impress the alternating voltage across each passage. The electrodes are insulated from the passages by the thin insulating plates forming the passages so that no current flows between the electrodes. Instead, the voltage creates a non-thermal plasma in the passages that increases the activity of electrons in the exhaust gases and initiates breakdown of the NOx and other reaction products in the gases. The reactions are then completed in a downstream catalytic converter, resulting in reduced emissions of NOx as well as other controlled emissions in the treated exhaust gases.
Abstract:
An exhaust treatment system is provided for use with an internal combustion engine of a motor vehicle. The exhaust treatment system includes a parallel plate, monolithic plasma reactor for reducing nitrogen oxides in the exhaust gas from the engine, an electric power source for providing an electrical signal to the electrodes of the plasma reactor, and a controller interconnected between the electric power source and the plasma reactor for modulating the electrical signal to the plasma reactor. More specifically, the electric power source provides an alternating current electrical signal and the controller modulates the electrical signal off in accordance with a predetermined duty cycle, thereby achieving uniform barrier discharge in the plasma reactor.
Abstract:
A simplified, low cost method for preparing a non-thermal plasma reactor comprises forming cell building blocks of material having a high dielectric constant, printing a conductive print onto the cell walls, assembling the cells into a multi-cell stack, providing electrical connections for connecting said cells to a high voltage source, applying insulation to said multi-cell stack, and inserting the multi-cell stack into a non-thermal plasma reactor housing. The simplified design eliminates the need for spacers between individual cells, thus reducing the total number of components. The method employing formed shape building blocks provides flexibility and may be used in conjunction with conventional processing methods. The printing sequence is defined from the top of the multi-cell stack to the bottom, further minimizing the number of components. Use of a three-dimensional conductive print further simplifies preparation by eliminating the need for a secondary conductive print along the edge of the stack.
Abstract:
A scaleable inter-digitized tine non-thermal plasma reactor element includes at least one pair of inter-digitized tine end connectors connected together defining gas passages between the tines. The prepared inter-digitized tine reactor element has a scaleable height, width, and length. Connectors are defined that enable efficient non-thermal reactor element fabrication for widely varying applications having various flow throughput and constituent reduction requirements. An inter-digitized tine reactor element is provided having several zones that are selectively powered so that the effective length of the reactor can be adjusted during operation for optimal efficiency over a range of operating conditions Structural carrier connectors and structural conductor connectors are provided. Structural carrier connectors have tines defined in a side to side basis comprising a high-k dielectric layer, electrode layer, structural dielectric, electrode layer, and high-k dielectric layer. Structural conductor connectors have tines defined in a side to side basis comprising a high-k dielectric layer, structural conductor, and high-k dielectric layer. The scaleable reactors include double, single or null dielectric barrier inter-digitized tine non-thermal plasma reactors. The double dielectric barrier reactor has plasma cells bounded by a dielectric barrier in the plasma direction. The single dielectric barrier reactor has plasma cells bounded by a dielectric barrier on one side and by an electrode on the opposite side, in the plasma direction. The null dielectric barrier reactor has plasma cells bounded by electrodes on each side, in the plasma direction.
Abstract:
A NOx, catalyst combination for treating a lean exhaust gas stream comprising an alkaline earth-alumina catalyst and an alkaline earth-zeolite catalyst, arranged on a substrate such that the gas stream first contacts the alkaline earth-alumina catalyst prior to contacting the alkaline earth-zeolite catalyst.
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. The system and method are particularly suitable for gas pretreatment and regeneration of a downstream diesel particulate filter.
Abstract:
A poison resistant lean NOx catalyst comprising: a protective coating of a first catalyst support material including a metal-zirconium phosphate component, coated on a second NOx occluding catalyst material.
Abstract:
An exhaust management control method comprising the steps of: immediately following a cold start of an engine, adsorbing hydrocarbons from engine exhaust into a hydrocarbon adsorber; determining when a catalytic converter catalyst light-off is obtained and thereafter purging the adsorber, wherein a first regeneration of the adsorber is obtained; detecting an engine off condition of the vehicle; and injecting air through the adsorber following the detected engine off condition while the adsorber is hot enough that coke deposits thereon are oxidized and thereby removed from the adsorber, wherein a second regeneration of the adsorber is achieved.
Abstract:
A non-thermal plasma (NTP) reactor structural conductor element includes a base conductor support and a high dielectric constant (“high k”) barrier layer supported by and substantially surrounding the base conductor support to form a structural conductor NTP reactor element. The structural conductor element may comprise a variety of shapes such as plates, sheets, half-box, I shapes, C shapes, or comb shapes, among others. In one embodiment, the dielectric barrier layer includes a coating applied to the base conductor support. In another embodiment, the dielectric barrier layer includes a high k film laminated to the base conductor support. In yet another embodiment, the base conductor support integrally forms the dielectric barrier layer via conversion of surfaces of the base conductor using electrochemical, thermal or chemical means to form the dielectric barrier layer.
Abstract:
A non-thermal plasma reactor element is provided comprising a multi-cell stack prepared from a plurality of formed building blocks of dielectric material, the walls of the building blocks defining a cell having an exhaust passage for flowing gas to be treated therethrough. A conductive print forming an electrode and connector is disposed on at least one wall of each of the cells and outer insulative plates, disposed on opposite ends of the multi-cell stack, are provided to protect the conductive print. The simplified design eliminates the need for spacers between individual cells, thus reducing the total number of components. Use of a three-dimensional conductive print further simplifies preparation by eliminating the need for a secondary conductive print along the edge of the multi-cell stack after assembly.