Sulfur-Resistant Exhaust Gas Aftertreatment System For The Reduction Of Nitrogen Oxides
AssigneeMAN Nutzfahrzeuge AG
InventorAndreas DORING
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Abstract
An arrangement for aftertreatment of exhaust gas for lean-burn internal combustion engines such as diesel engines and Otto engines with direct injection has a NOx storage catalyzer installed in the exhaust gas train for reducing nitrogen oxides and at which nitrogen oxides are stored in lean operating phases and these stored nitrogen oxides are reduced in rich operating phases. At least one molecular sieve which keeps sulfur dioxide away from the at least one NOx storage catalyzer is arranged upstream of the NOx storage catalyzer.
Claims26
Apparatus for after-treatment exhaust gas in the exhaust gas train of a lean-burn internal combustion engine, the exhaust gas train having an input and an output, the apparatus comprising:
- an NOx storage catalyzer installed in the exhaust gas train, the catalyzer having at least one storage component for storing nitrogen oxides during lean operating phases and at least one active component for reducing stored nitrogen oxides during rich operating phases;
- and
- a molecular sieve arranged upstream of the NOx storage catalyzer, the molecular sieve preventing sulfur dioxide from reaching the catalyzer.
A method for producing an apparatus for after-treatment exhaust gas in the exhaust gas line of a lean-burn internal combustion engine, the method comprising:
- producing an NOx storage catalyzer by one of extrusion and coating a substrate, the NOx storage catalyzer having at least one storage component for storing nitrogen oxides during lean operating phases and at least one active component for reducing stored nitrogen oxides during rich operating phases;
- and
- providing a molecular sieve layer on the NOx storage catalyzer, the molecular sieve layer preventing sulfur dioxide from reaching the catalyzer.
The method of claim 24 further comprising arranging a catalytic layer on the molecular sieve layer, the catalytic layer having at least one active component for oxidation of hydrocarbons.
Dependencies are inferred from the claim text.