Patent ID: 8109081

Claim:
Method for controlling hydrocarbon delivery to a hydrocarbon selective catalytic reduction device configured to receive an exhaust gas flow from an internal combustion engine, comprising: monitoring measurable variable terms including factors affecting a conversion efficiency in the hydrocarbon selective catalytic reduction device, the terms comprising: a temperature of a catalyst within the device; a space velocity of the exhaust gas flow moving through the device; an oxygen concentration of the exhaust gas flow; and a NOx concentration of the exhaust gas flow; determining classifications of the terms based upon measurable variable ranges selected through statistical analysis of the terms, the analysis comprising: changing in iterations one of the terms at a time through a range of values; for each iteration, examining an effect on the conversion efficiency; identifying breakpoints in the terms; and defining the measureable variable ranges based upon the breakpoints; determining a desired hydrocarbon delivery value range based upon the classifications; and utilizing the desired hydrocarbon delivery value range to control the hydrocarbon delivery to the hydrocarbon selective catalytic reduction device.