Patent ID: 8006481
Filing Date: 2011-08-30
Classification: F01N,Y02A,Y02T

Abstract:
1. Method to selectively reduce NO x emissions in an exhaust gas feedstream of an internal combustion engine, comprising: determining a NOx concentration and a mass flow rate of the exhaust gas feedstream and an inlet temperature to a silver-alumina catalytic reactor device; determining a preferred hydrocarbon/NOx ratio to reduce the NOx concentration across the silver-alumina catalytic reactor device, the preferred hydrocarbon/NOx ratio varying in response to the NOx concentration, the mass flow rate of the exhaust gas feedstream and the inlet temperature to the silver-alumina catalytic reactor device; determining a quantity of hydrocarbon reductant that achieves the preferred hydrocarbon/NOx ratio in the exhaust gas feedstream upstream of the silver-alumina catalytic reactor device; dispensing the quantity of hydrocarbon reductant into the exhaust gas feedstream upstream of the silver-alumina catalytic reactor device; and selectively controlling a mass flow rate of hydrogen in the exhaust gas feedstream upstream of the silver-alumina catalytic reactor device.