Patent ID: 6192677
Filing Date: 2001-02-27
Classification: B01D,F01N,Y02A,Y02T

Abstract:
An apparatus for after-treating exhaust gases of an internal combustion engine operating with excess air, comprising:a reduction catalytic converter for reducing NO.sub.x components in an exhaust gas flowing in an exhaust gas line of an internal combustion engine;an electrically driven metering device for controlled injection of reducing agent into the exhaust-gas line upstream of the reduction catalytic converter in a flow direction of the exhaust gas, said metering device having an injection valve and a double-walled valve holding element enclosing said injection valve and directly communicating with the exhaust-gas line, said double-walled valve holding element having an outer wall and an inner wall and an air gap formed therebetween; anda device for cooling the metering device, including a pressurized-air generating device connected to blow pressurized air into said air gap between said outer wall and said inner wall of said valve holding element, for cooling said injection valve in vicinity of the exhaust gas line.