Method for operating an exhaust emission control system having a SCR-catalyst and an upstream oxidation catalyst exhaust emission control component
AssigneeDaimler AG
InventorAlexander Massner
Life of this patent
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Abstract
A method for operating an exhaust emission control system of a motor vehicle internal combustion engine, in the exhaust gas line of which an oxidation-catalytically active exhaust emission control component is arranged upstream of a SCR-catalyst is provided. An ageing state of the oxidation-catalytically active exhaust emission control component is determined by correlating a hydrocarbon fraction present in the exhaust emission upstream of the oxidation-catalytically active exhaust emission component with a simultaneous nitrogen oxide conversion of the SCR-catalyst.
Claims18
A method for operating an exhaust gas emission control system of a motor vehicle internal combustion engine, in the exhaust gas line of which an oxidation-catalytically active exhaust gas emission control component is arranged upstream of a SCR-catalyst, the method comprising:
- adjusting different hydrocarbon fractions in the exhaust gas upstream of the oxidation-catalytically active exhaust gas emission control component;
- determining an ageing state of the oxidation-catalytically active exhaust gas emission control component by correlating a hydrocarbon fraction present in the exhaust gas emission upstream of the oxidation-catalytically active exhaust emission component with a simultaneous nitrogen oxide conversion of the SCR-catalyst, wherein a hydrocarbon fraction associated with an undercutting of a presettable nitrogen oxide conversion is used as the basis for determining the ageing state;
- and
- adjusting operation of the internal combustion engine or the exhaust gas emission control system based on the determined ageing of the oxidation-catalytically active exhaust gas emission control component.
A method, comprising:
- supplying exhaust gas to an exhaust gas emission control system of a motor vehicle internal combustion engine, wherein the exhaust gas emission control system includes an oxidation-catalytically active exhaust gas emission control component arranged upstream of a SCR-catalyst;
- entering a checking routine to evaluate ageing of the oxidation-catalytically active exhaust gas emission control component, wherein the checking routine comprises
- adjusting the exhaust gas upstream of the oxidation-catalytically active exhaust gas emission control system to have a first hydrocarbon fraction;
- determining a first nitrogen oxide conversion of the SCR-catalyst for the exhaust gas having the first hydrocarbon fraction;
- adjusting the exhaust gas upstream of the oxidation-catalytically active exhaust gas emission control system to have a second hydrocarbon fraction;
- determining a second nitrogen oxide conversion of the SCR-catalyst for the exhaust gas having the second hydrocarbon fraction;
- determining an ageing state of the oxidation-catalytically active exhaust gas emission control component by
- generating a first correlation of the first hydrocarbon fraction with the first determined nitrogen oxide conversion of the SCR-catalyst;
- generating a second correlation of the second hydrocarbon fraction with the second determined nitrogen oxide conversion of the SCR-catalyst;
- and
- comparing the first and second correlations to stored correlation values;
- adjusting operation of the internal combustion engine or the exhaust gas emission control system based on the determined ageing of the oxidation-catalytically active exhaust gas emission control component,
- wherein the first and second hydrocarbon fractions are greater than zero.
A method for operating an exhaust gas emission control system of a motor vehicle internal combustion engine, in the exhaust gas line of which an oxidation-catalytically active exhaust gas emission control component is arranged upstream of a SCR-catalyst, the method comprising:
- introducing hydrocarbon into exhaust gas such that a presettable hydrocarbon fraction is present in the exhaust gas upstream of the oxidation-catalytically active exhaust gas emission control component;
- introducing ammonia or urea solution into the exhaust gas downstream of the oxidation-catalytically active component and upstream of the SCR catalyst;
- determining a NOx conversion of the SCR catalyst caused by reduction of NOx with ammonia in the SCR catalyst, wherein the introduction of the hydrocarbon and the introduction of the ammonia or urea solution and the NOx conversion occur simultaneously;
- determining an ageing state of the oxidation-catalytically active exhaust gas emission control component by correlating the hydrocarbon fraction with the NOx conversion;
- and
- adjusting operation of the internal combustion engine or the exhaust gas emission control system based on the determined ageing of the oxidation-catalytically active exhaust gas emission control component.
Dependencies are inferred from the claim text.