Abstract: An exhaust stream aftertreatment system that selectively reduces NOx emissions during lean-burn operation of an internal combustion engine is provided. The apparatus includes a partial oxidation reactor having a fuel source, an ignition device, and various values. The partial oxidation reactor is disposed in the exhaust pipe of automobile between the engine and the threeway catalyst. A light-off catalyst is provided adjacent to the engine, upstream from the partial oxidation reactor. The three-way catalyst and the light-off catalyst are typical automotive catalysts having a substrate plated with a precious metal to facilitate the oxidation of hydrocarbons (HC) and carbon monoxide (CO) as well as the reduction of nitrogen monoxide and nitrogen dioxide (NOx). The partial oxidation reactor is adapted to operate while the internal combustion engine is producing high levels of NOx or while the engine is operating in a lean burn regime.

Abstract: A combination catalytic converter and heat exchanger unit that controls the temperature of one or more catalytic converters within their efficient conversion operating temperature ranges. The unit includes a plurality of spaced apart tubes through which the exhaust emissions flow through the unit. Each of the plurality of tubes includes a substrate on which is formed a catalyst that reduces or eliminates harmful by-products in the exhaust emissions. A cooling system, such as a fan, forces a cooling fluid, such as air, around the tubes to cool the catalyst to be within its efficient operating temperature range. The tubes have a suitable diameter that allows the center of the tubes to be effectively cooled. The speed of the fan is controlled to variably adjust the temperature of the exhaust emissions in response to various input data, such as the temperature of the exhaust emissions at different locations in the exhaust path, engine speed and load, and the type of catalyst being used.

Abstract: A system for adjusting the temperature of the exhaust emissions from an internal combustion engine so that it is at a temperature that maintains one or more catalysts at their effective operating temperature. This has particular application for NOx control from any lean-burn engine. The system includes a heat exchanger that cools the exhaust emissions by forced air from a variable speed fan. The cooled exhaust emissions are directed from the heat exchanger to the catalyst for conversion. The fan speed is controlled to adjust the amount of cooling of the exhaust emissions in response to various input data, such as the temperature of the exhaust emissions at different locations in the exhaust pipe, engine speed, engine load and the catalyst being used. Two or more catalysts can be incorporated at different locations along the exhaust path and have different operating temperatures so as to control the effectiveness of exhaust emissions conversions for increased efficiency and reduced energy consumption.