Plasma reactor having regions of active and passive electric field

A multi-unit plasma reactor for reducing NOx in automotive exhaust gas, comprising:

• a plurality of mutually juxtaposed plasma reactors, each plasma reactor comprising:
• a dielectric plasma reactor wall, said dielectric plasma reactor wall defining a reactor space;
• an inner electrode disposed within said reactor space in parallel relation to said plasma reactor wall;
• and
• an outer electrode adjoining said plasma reactor wall, said outer electrode being arranged in a sequential pattern comprising a series of discretely spaced apart locations, said sequential pattern being arranged with respect to an axis.

A treatment system for automotive exhaust gas, comprising:

• at least one plasma reactor comprising:
• a dielectric plasma reactor wall forming a reactor space, said dielectric plasma reactor wall having an inlet and an outlet for exhaust gas entry and exit, respectively, with regard to said reactor space;
• an inner electrode disposed within said reactor space in parallel relation to said dielectric plasma reactor wall;
• and
• an outer electrode adjoining said plasma reactor wall, said outer electrode being arranged in a sequential pattern comprising a series of discretely spaced apart locations, said sequential pattern being arranged with respect to an axis;
• and
• a catalytic converter connected to said outlet of said at least one plasma reactor.

A method for reducing NOx from automotive exhaust gas having hydrocarbons, comprising the steps of:

• providing a stream of exhaust gas moving generally parallel with respect to an axis;
• subjecting the gas to a region of high voltage extending for a short distance parallel to the axis;
• subjecting the gas immediately thereafter to voltage lower than said high voltage for a long distance parallel to the axis;
• and
• sequentially repeating a selected number of times said first and second steps of subjecting;
• wherein atoms, radicals and ions are produced in the gas by the first step of subjecting, and wherein NOx in the gas is reduced by interaction of the NOx with the atoms, ions and radicals during said second step of subjecting.