Methods and systems are provided for addressing engine cold-start emissions while an exhaust catalyst is activated. In one example, a method for improving exhaust emissions may include flowing ionized air into an engine exhaust, downstream of an exhaust catalyst, to oxidize exhaust emissions left untreated by the catalyst. The approach reduces the PM load of the exhaust as well as of a downstream particulate matter filter.

An exhaust treatment system comprises an excitation chamber that generates a plasma field to excite a stream of exhaust gas and a mixing chamber that allows a portion of the exhaust gas stream to be oxidized. The excitation chamber comprises an inner housing, an outer housing, and an exhaust inlet that directs a stream of exhaust gas to enter into the outer housing of the excitation chamber. The enclosure of the inner housing includes orifices that allow at least a portion of the exhaust gas to enter into the inner housing from the outer housing. The inner housing includes electrodes for generating the plasma field. The inner wall of the inner housing includes a surface topology that cooperates with the orifices of the enclosure to entrain the exhaust gas to travel in a coherent-structured turbulence flow form in the inner housing.

A nitrogen oxide (NOx) abatement system is provided. The system includes a power generation device for generating power from a hydrogen-element containing fuel, an exhaust conduit in flow communication with an exhaust stream containing NOx which comes from the power generation device, a plasma reactor for reforming a portion of the hydrogen-element containing fuel with nitrogen to produce ammonia, and a NOx abatement reactor containing ammonia selective catalytic reduction (NH3-SCR) catalyst for receiving the exhaust stream and the ammonia and reducing NOx in the exhaust stream by causing the NOx to react with the ammonia to form nitrogen.

A system for exhaust gas remediation includes an engine, a plasma reactor, and a pulse source. The engine emits exhaust gas that includes NO molecules and NOx molecules. The plasma reactor includes an internal chamber that is fluidly connected to the engine such that the exhaust gas flows into the internal chamber. An electrode is disposed within the internal chamber of the plasma reactor. The electrode is electrically coupled to an electrical pulse source. The electrical pulse source delivers electrical pulse to the electrode to form a plasma from the exhaust gas, which removes at least a portion of the NO molecules and at least a portion of the NOx molecules.

Disclosed is a nonthermal plasma-based exhaust gas particulate matter reduction apparatus for preventing an arcing phenomenon, the apparatus comprising: a chamber which is a tubular body having exhaust gas flowing therein and is connected to a ground power supply; a power supply device which is disposed outside the chamber and includes a voltage generation unit for generating a steady-state voltage at which maximum efficiency of a nonthermal plasma phenomenon is generated; an emitter which is disposed inside the chamber and generates nonthermal plasma between the chamber by having the steady-state voltage applied thereto; a rod which applies the steady-state voltage to the emitter by electrically connecting the voltage generation unit and the emitter; and an arcing prevention unit which prevents an arcing phenomenon from occurring between the rod and the chamber by providing insulation between the rod and the chamber.

A system for exhaust gas remediation includes an engine, a plasma reactor, and a pulse source. The engine emits exhaust gas that includes NO molecules and NO.sub.x molecules. The plasma reactor includes an internal chamber that is fluidly connected to the engine such that the exhaust gas flows into the internal chamber. An electrode is disposed within the internal chamber of the plasma reactor. The electrode is electrically coupled to an electrical pulse source. The electrical pulse source delivers electrical pulse to the electrode to form a plasma from the exhaust gas, which removes at least a portion of the NO molecules and at least a portion of the NO.sub.x molecules.

A modular plasma treatment system has interchangeable and easily accessible inner and outer electrodes that concentrically nest within an outer housing of one or more plasma reformers. The inner and outer electrodes have self-centering features that allow for blind-fitting of the interchangeable inner and outer electrodes during electrode replacement and maintenance. A plurality of reformers that generate different types of plasmas are preferably arranged serially to allow for a mixture of separate plasmas within the same reaction area and to increase utilization of short-lived radicals.

A modular plasma treatment system has interchangeable and easily accessible inner and outer electrodes that concentrically nest within an outer housing of one or more plasma reformers. The inner and outer electrodes have self-centering features that allow for blind-fitting of the interchangeable inner and outer electrodes during electrode replacement and maintenance. A plurality of reformers that generate different types of plasmas are preferably arranged serially to allow for a mixture of separate plasmas within the same reaction area and to increase utilization of short-lived radicals.

A modular plasma treatment system has interchangeable and easily accessible inner and outer electrodes that concentrically nest within an outer housing of one or more plasma reformers. The inner and outer electrodes have self-centering features that allow for blind-fitting of the interchangeable inner and outer electrodes during electrode replacement and maintenance. A plurality of reformers that generate different types of plasmas are preferably arranged serially to allow for a mixture of separate plasmas within the same reaction area and to increase utilization of short-lived radicals.