Method of reducing internal combustion engine emissions, and system for same

Abstract

A method and system for reducing pollutant concentration within an internal combustion engine exhaust stream is disclosed. Soot and products of incomplete combustion in the engine exhaust stream are destroyed by oxidizing them in a flameless thermal oxidizer that contains a matrix of heat-resistant media. Methods and systems for increasing particle residence time within the thermal oxidizer are also disclosed. These techniques include employing electrostatic precipitation, centrifugal force, and particle impaction sections. A method and system for reducing oxides of nitrogen (NOx) emissions is also disclosed. Low NOx concentration may be obtained by adding a SCR system after a thermal oxidizer, by tuning the engine to produce low NOx/high soot and destroying the soot in a thermal oxidizer, and by injecting a reductant into the thermal oxidizer. The flameless thermal oxidizer may be located between the engine and a turbo-charger to enhance thermal efficiency and to reduce turbo-charger wear. The thermal oxidizer comprises longitudinal and radial flow systems, which each may include a reaction wave of the following shapes: planar, cylindrical, Bunsen, Burke-Schumann, and an inverted V. An engineered matrix is disclosed to manipulate the shape of the reaction zone.