Apparatus and method for the after-treatment of exhaust gases from an internal combustion engine operating with excess air
AssigneeSiemens Aktiengesellschaft
InventorRainer Tost
Life of this patent
Estimating the term…
Abstract
An injection valve of a reducing agent metering device is enclosed in a double-walled valve holding element that is connected directly to the exhaust-gas line. It is thereby possible to blow pressurized air into an air gap between an outer wall and an inner wall of the valve holding element and, as a result, to cool at least those parts of the injection valve that are in close vicinity to the exhaust gas.
Claims20
An apparatus for after-treating exhaust gases of an internal combustion engine operating with excess air, comprising:
- a reduction catalytic converter for reducing NOx 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;
- and
- a 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.
A method of after-treating exhaust gases from an internal combustion engine operating with excess air and having an exhaust-gas after-treatment system, which comprises:
- introducing reducing agent into an exhaust-gas line with an electrically driven metering device comprising an injection valve enclosed by a double-walled valve holding element connected directly to the exhaust-gas line;
- generating pressurized air with a pressurized-air generating device and blowing the pressurized air into an air gap between an outer wall and an inner wall of the double-walled valve holding element, and thereby cooling at least those parts of the injection valve in vicinity to the exhaust gas by means of the pressurized air;
- and
- reducing NOx components in the exhaust gas by means of a reduction catalytic converter disposed downstream of the metering device, in an exhaust gas flow direction.
Dependencies are inferred from the claim text.