Abstract: An exhaust gas aftertreatment installment and associated exhaust gas aftertreatment method utilizes a nitrogen oxide storage catalytic converter and an SCR catalytic converter. A particulate filter is provided upstream of the nitrogen oxide storage catalytic converter or between the latter and the SCR catalytic converter or downstream of the SCR catalytic converter. The time of regeneration operating phases of the nitrogen oxide storage catalytic converter can be determined as a function of the nitrogen oxide content of the exhaust gas downstream of the nitrogen oxide storage catalytic converter or of the SCR catalytic converter and/or as a function of the ammonia loading of the latter. Moreover, a desired ammonia generation quantity can be determined for a respective regeneration operating phase. The installation and method are adopted for use for motor vehicle internal combustion engines and other engines which are operated predominantly in lean-burn mode.

Abstract: The invention relates to a method for cleaning a particle filter (1) with the following method steps: a gaseous stream laden with pollutants and/or particles is fed to a particle filter (1) that operates catalytically and/or by filtration, pollutants and/or particles are chemically converted or stored in the particle filter (1), filtrate or ash particles (2) being produced and/or deposited on the particle filter (1). Once the particle filter (1) has been used for a specific period of time, a layer (3, 4) for increasing the through-flow resistance is applied to the layer of filtrate or ash particles (2) in the direction of filtration.

Abstract: The invention relates to a method for cleaning a particle filter (1) with the following method steps: a gaseous stream laden with pollutants and/or particles is fed to a particle filter (1) that operates catalytically and/or by filtration, pollutants and/or particles are chemically converted or stored in the particle filter (1), filtrate or ash particles (2) being produced and/or deposited on the particle filter (1). Once the particle filter (1) has been used for a specific period of time, a layer (3, 4) for increasing the through-flow resistance is applied to the layer of filtrate or ash particles (2) in the direction of filtration.

Abstract: An internal combustion engine includes an exhaust-gas aftertreatment device, and an operating method is for operating the internal combustion engine. The internal combustion engine is operable with a lean mixture and a rich mixture, the internal combustion engine having an exhaust-gas aftertreatment device, which includes a nitrogen oxide storage catalytic converter and a particle filter. When lean exhaust gas flows through the nitrogen oxide storage catalytic converter, it removes nitrogen oxides from the exhaust gas by storing them, and, when reducing exhaust gas flows through the nitrogen oxide storage catalytic converter, it produces ammonia through reduction of stored and/or supplied nitrogen oxides and releases it to the exhaust gas. Downstream from the nitrogen oxide storage catalytic converter, the exhaust-gas aftertreatment device includes a SCR catalytic converter, which reduces nitrogen oxides contained in the exhaust gas, using ammonia produced by the nitrogen oxide storage catalytic converter.

Abstract: A filter assembly for an exhaust gas purification system of an internal combustion engine. The filter assembly, has porous filter plate elements, connected with each other on their outer as well as on their inner peripheries, forming in pairs as filter pockets. Catalytic agents such as ammonia are applied to the filter pockets on the outer and/or inner sides to oxidize carbon black contained in the combustion gas. In particular, this filter assembly is compact and can be used for diesel engines of motor vehicles.

Abstract: An exhaust-gas aftertreatment device with a nitrogen oxide storage catalytic converter for an internal combustion engine, and a method for operating an exhaust-gas aftertreatment device which is assigned to an internal combustion engine and has a nitrogen oxide storage catalytic converter. An SCR catalytic converter is arranged in the exhaust-gas aftertreatment device, it being possible for the exhaust gas which emerges from the nitrogen oxide storage catalytic converter to be fed to the SCR catalytic converter when the internal combustion engine is in a desulphating operating mode with a reducing exhaust-gas composition, in order for H2S which is formed during the desulphating to be removed.

Abstract: An exhaust-gas aftertreatment device with a nitrogen oxide storage catalytic converter for an internal combustion engine, and a method for operating an exhaust-gas aftertreatment device which is assigned to an internal combustion engine and has a nitrogen oxide storage catalytic converter. An SCR catalytic converter is arranged in the exhaust-gas aftertreatment device, it being possible for the exhaust gas which emerges from the nitrogen oxide storage catalytic converter to be fed to the SCR catalytic converter when the internal combustion engine is in a desulphating operating mode with a reducing exhaust-gas composition, in order for H2S which is formed during the desulphating to be removed.

Abstract: A method for the desulfurization of a nitrogen oxide adsorber of an exhaust gas purification device for a combustion system employs desulfurization phases that are intermittently implemented by a desulfurization control unit. During each desulfurization phase, the carbon monoxide concentration and/or the lambda value of the exhaust gas stream exiting the nitrogen oxide adsorber is recorded. A localized maximum that appears in the recorded course of the carbon monoxide concentration over time, or a downward slope that appears in the established course of the lambda value over time, falling from a temporary plateau value, is employed as criterion for terminating the desulfurization phase. The method may be used, for example, in exhaust gas purification devices in primarily lean-burning vehicle combustion engines.

Abstract: An exhaust-gas aftertreatment device with a nitrogen oxide storage catalytic converter for an internal combustion engine, and a method for operating an exhaust-gas aftertreatment device which is assigned to an internal combustion engine and has a nitrogen oxide storage catalytic converter. An SCR catalytic converter is arranged in the exhaust-gas aftertreatment device, it being possible for the exhaust gas which emerges from the nitrogen oxide storage catalytic converter to be fed to the SCR catalytic converter when the internal combustion engine is in a desulphating operating mode with a reducing exhaust-gas composition, in order for H2S which is formed during the desulphating to be removed.

Abstract: A method for the desulfurization of a nitrogen oxide adsorber of an exhaust gas purification device for a combustion system employs desulfurization phases that are intermittently implemented by a desulfurization control unit. During each desulfurization phase, the carbon monoxide concentration and/or the lambda value of the exhaust gas stream exiting the nitrogen oxide adsorber is recorded. A localized maximum that appears in the recorded course of the carbon monoxide concentration over time, or a downward slope that appears in the established course of the lambda value over time, falling from a temporary plateau value, is employed as criterion for terminating the desulfurization phase. The method may be used, for example, in exhaust gas purification devices in primarily lean-burning vehicle combustion engines.

Abstract: A method for operating an exhaust-gas cleaning system having an NOx adsorption accumulator and an SOx trap, includes, in normal operating phases, feeding the exhaust gas to be cleaned first via the SOx trap and then via the NOx adsorption accumulator. The normal operating phases are from time to time interrupted by desulphurization phases for desulphurizing the SOx trap. Means are provided for controlling the direction of flow of the exhaust stream so that it optionally passes firstly via the SOx trap and then via the NOx adsorption accumulator, or firstly via the NOx adsorption accumulator and then via the SOx trap, so that during the desulphurization phases the exhaust gas can be passed firstly via the NOx adsorption accumulator and then via the SOx trap.

Abstract: In an emission control system that includes a particle filter, an arrangement is provided upstream of the particle filter, the arrangement being configured to prevent the development of ash-forming compounds of sulfur in the exhaust. The emission control system may be used with a diesel engine.

Abstract: A filter assembly for an exhaust gas purification system of an internal combustion engine. The filter assembly, has porous filter plate elements, connected with each other on their outer as well as on their inner peripheries, forming in pairs as filter pockets. Catalytic agents such as ammonia are applied to the filter pockets on the outer and/or inner sides to oxidize carbon black contained in the combustion gas. In particular, this filter assembly is compact and can be used for diesel engines of motor vehicles.

Abstract: A method for operating an exhaust-gas cleaning system having an NOX adsorption accumulator and an SOX trap, includes, in normal operating phases, feeding the exhaust gas to be cleaned first via the SOX trap and then via the NOX adsorption accumulator. The normal operating phases are from time to time interrupted by desulphurization phases for desulphurizing the SOX trap. Means are provided for controlling the direction of flow of the exhaust stream so that it optionally passes firstly via the SOX trap and then via the NOX adsorption accumulator, or firstly via the NOX adsorption accumulator and then via the SOX trap, so that during the desulphurization phases the exhaust gas can be passed firstly via the NOX adsorption accumulator and then via the SOX trap.

Abstract: A process and apparatus for reducing the nitrogen oxide content in oxygen-containing emissions is provided, particularly for internal-combustion engines, particularly of diesel engines and directly injecting Otto engines for motor vehicles. The nitrogen oxides contained in the exhaust gas are reduced by a suitable reducing agent, such as hydrogen or hydrocarbons, on a DENOX catalyst. For achieving an improved conversion rate for the nitrogen oxides, a combination of hydrogen and hydrocarbons are used as reducing agents. In different operating ranges of the internal-combustion engine only hydrogen, only hydrocarbons, or hydrogen and hydrocarbons are added. Preferably, for this purpose, the quantity of supplied hydrogen or hydrocarbons is reduced or increased with an increasing engine load and/or catalyst temperature and/or rotational engine speed.

Abstract: A diesel fuel containing an additive which improves the combustion of soot, for reducing the pollutant emission in the combustion exhaust gases from diesel engines by discontinuous burning-off of soot which has been precipitated in the exhaust gas filter, is described. For this purpose, a lithium, sodium or potassium salt of an aliphatic or aromatic alcohol, of a phenol, of an aliphatic acid or of a naphthoic acid, phenylacetic acid or cinnamic acid is added, singly or as a mixture, to the diesel fuel before the combustion of the latter in the internal combustion engine. As a result of the addition of the alkali metal salts, the ignition temperature of the soot precipitated in the particle filter is reduced, and the soot is oxidized at a temperature which is considerably lower than the normal ignition temperature. The regeneration range for the particle filter is therefore reached much more frequently in real running practice.