Abstract:
Die vorliegende Erfindung betrifft ein SCR-aktives Material, das einen kleinporigen Zeolithen, Aluminiumoxid und Kupfer umfasst, dadurch gekennzeichnet, dass es bezogen auf das gesamte Material 5 bis 25 Gew.-% Aluminiumoxid enthält und das Kupfer auf dem Aluminiumoxid in einer ersten Konzentration und auf dem kleinporigen Zeolithen in einer zweiten Konzentration vorliegt.
Abstract:
The invention relates to a method for reactivating a system composed of an oxidation catalytic converter (5) followed by a possibly catalytically coated particle filter (6), and to a correspondingly adapted exhaust-gas purification system for lean-burn engines (1) with low pressure EGR (14). The present invention relates in particular to the reactivation of such a system during overrun operation of the engine.
Abstract:
The present invention relates to an exhaust-gas aftertreatment system which comprises a preferably catalytically active particle filter (wall-flow filter) which is followed in turn by a throughflow monolith (flow-through monolith) which is preferably provided with a catalytically active function. Both components have the same storage functions for gaseous substances present in the exhaust gas of internal combustion engines. The system is suitable in particular for the simultaneous removal of particles and pollutants from the exhaust gas of both predominantly lean-operated internal combustion engines and also of internal combustion engines operated predominantly with a stoichiometric air/fuel mixture. Likewise described is a process for the production and the use of such a system for exhaust-gas aftertreatment.
Abstract:
The use of nitrogen oxide storage catalytic converters in a position near the engine for purifying the exhaust gases of gasoline engines using direct gasoline injection, which are operated primarily with lean air/fuel mixtures, presents particular challenges for the temperature resistance and fatigue resistance of the catalysts to be used. The invention relates to a nitrogen oxide storage catalytic converter suitable for said application and comprising two catalytically active coatings for a support body. The base coating, applied directly to the carrier body, has a nitrogen oxide storage function and comprises platinum as a catalytically active component applied to a homogenous magnesium-aluminum mixed oxide in combination with a nitrogen oxide storage material in which a nitrogen oxide storage component is also present and applied to a homogenous magnesium-aluminum mixed oxide. The magnesium-aluminum mixed oxides used have different compositions. The second coating applied thereto is characterized by three-way catalytic activity and comprises palladium applied to aluminum oxide and barium oxide or strontium oxide, but no platinum.
Abstract:
The invention relates to a method for reactivating a system composed of an oxidation catalytic converter (5) followed by a possibly catalytically coated particle filter (6), and to a correspondingly adapted exhaust-gas purification system for lean-burn engines (1) with low pressure EGR (14). The present invention relates in particular to the reactivation of such a system during overrun operation of the engine.
Abstract:
The present invention relates to a process for purifying NO x -containing exhaust gases formed in an internal combustion engine. In particular, the invention is directed at the purification of exhaust gases from an engine which produces a lean-burn exhaust gas, e.g. a diesel engine or a spark-ignition engine operated under lean conditions. Furthermore, the present invention relates to an appropriately equipped exhaust gas purification apparatus. The apparatus proposes a sequence of different catalysts for purifying primary axhaust gas of lean-burn engines, in which an oxidatively active particle filter (1) is followed by an oxidation catalyst (2) and this is in turn followed by an SCR catalyst, (3c) with the latter being arranged downstream of an addition of reducing agent (3a) located downstream of the oxidation catalyst (2).
Abstract:
The present invention relates to a method for the treatment of an exhaust gas comprising NOx, wherein the method comprises the step of subjecting the exhaust gas to an exhaust gas treatment system comprising, in order of the exhaust stream: (a) a first NOx storage catalytic converter (2, 2' ); (b) a catalytic converter (3) for selective catalytic reduction (SCR) downstream of the first NOx storage catalytic converter; and (C) a catalytic converter (4) having oxygen storage capacity downstream of the SCR catalytic converter; wherein the exhaust gas treatment system is operated in alternating rich and lean phases, wherein the rich phase is terminated when the amount of reducing components leaving the first NOx storage catalytic converter is at least 0.05 times the amount of reducing components consumed by the first NOx storage catalytic converter during the time interval beginning when the air/fuel ratio upstream of the first NOx storage catalytic converter turns from lean to rich conditions and ending when the air/ fuel ratio downstream of the first NOx storage catalytic converter turns from lean to rich conditions. Optionally there can be provided a close coupled three-way or diesel oxidation or NOx storage catalytic converter (1, 1').