Patent ID: 6919047

Claim:
A reductant injection system for reducing exhaust gas NO x in lean-burn engines, comprising: a catalytic reactor having an inlet end which receives exhaust gas containing NO x , an outlet end which outputs converted exhaust gas, and a port; a catalyst mounted inside the catalytic reactor for reducing NO x in the received exhaust gases to N 2 in the presence of a fuel, wherein the catalyst comprises a perovskite compound represented by the formula AB 1-x PM x O 3 , where A is a rare-earth metal, B is a transition metal, PM is a precious metal, and O is oxygen, and is positioned downstream of the port in catalytic reactor; and a fuel injector coupled to the port in the catalytic reactor and being positioned upstream of the catalyst, wherein the fuel injector injects diesel fuel in the exhaust gas prior to the exhaust gas passing through the catalyst, wherein the fuel is used as a reductant.