Daimler Chrysler Ag

Daimler Ag

Mercedes-benz Aktiengesellschaft

Daimlerchrylser Ag

Michel Weibel

Bernd Krutzsch

Guenter Wenninger

Andreas Hertzberg

Stefan Renfftlen

Rolf Wunsch

Markus Paule

Walter Boegner

Arno Nolte

Brigitte Konrad

Norbert Waldbuesser

Brigitte Bandl-Konrad

Frank Duvinage

Stefan Pischinger

Marko Weirich

G&uuml;nter Wenninger

Klaus Binder

Dirk Voigtlaender

Thomas Liebscher

Dirk Voigtl&auml;nder

Josef G&uuml;nther

Christof Sch&ouml;n

Friedrich Wirbeleit

Martin Hartweg

Berthold Keppeler

Viktor Pfeffer

Gregor Renner

Rudolf Maly

Tillmann Braun

Hans Fausten

Nicholas Fekete

Walter Friess

Norbert Ruzicka

Holger Adler

Anton Kerckhoff

Günter Wenninger

Rudiger Pfaff

Karl-Ernst Haak

Klaus-Juergen Marquardt

Oliver Ebelsheiser

Hans-Peter Holzt

Dirk Voigtländer

Oliver Abet

Heinz-Jost &Ouml;lschlegel

Kirsten Hardenberg

Doris Schr&ouml;der

G&uuml;nter Karl

Renate Marx

Dirk Voightl&auml;nder

Josef Guenther

Josef Günther

Brititte Konrad

Christof Schon

Heinz-Jost Ölschlegel

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.

Exhaust gas aftertreatment installation and method

The exhaust gas aftertreatment device according to the invention having a reforming unit for generating hydrogen by steam reforming, partial oxidation of hydrocarbons and/or mixed forms thereof is distinguished by the fact that the reforming unit is arranged directly in the main exhaust gas stream from an internal combustion engine. The steam and residual oxygen which are required for the reforming preferably originate from the exhaust gas. The step of providing the required reducing agents consists in briefly switching the internal combustion engine, which is predominantly operated in lean-burn mode and the exhaust gas from which is undergoing the aftertreatment, to rich-burn mode, allowing reforming by means of the reforming reactor according to the invention using the hydrocarbons that are present in the exhaust gas.

Device and method for exhaust gas aftertreatment

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.

Exhaust-gas aftertreatment device with nitrogen oxide storage catalytic converter, and operating method therefor

An exhaust-gas cleaning system for cleaning exhaust gas from a combustion source so as to remove at least nitrogen oxides contained therein is provided. An ammonia-generation catalytic converter for generating ammonia uses constituents of at least some of the exhaust gas emitted from the combustion source during ammonia-generation operating phases. A downstream nitrogen oxide reduction catalytic converter is provided for reducing nitrogen oxides which are contained in the exhaust gas emitted from the combustion source using the ammonia generated as the reducing agent. According to the invention, a plasma generator for using plasma technology to generate reactive particles, which promote the ammonia-generation reaction, from constituents of the exhaust gas fed to the ammonia-generation catalytic converter during the ammonia-generation operating phases is connected upstream of the ammonia-generation catalytic converter. This ensures that sufficient ammonia is generated even at relatively low exhaust-gas temperatures.

Exhaust gas cleaning system having internal ammonia production for reducing nitrogen oxides

In a method for burning deposited soot particles in a particle filter on an exhaust device of a diesel engine, first of all, in a known way, a catalytic converter produces NO from exhaust gas. This NO reduces the ignition temperature of soot to such an extent that it burns at normal exhaust-gas temperature. Furthermore, there is provision to add fuel additive, which likewise allows the ignition temperature of the soot to be reduced. The sulphur content in the fuel is determined, and either generation of NO or the addition of additive is used as a function of this measurement. This preferably takes place automatically. To determine the sulphur content, it is possible, for example, to use a sulphur sensor in the tank.

Method and device for treating diesel exhaust gas

In a method for operating an internal combustion engine using exhaust gas purification system, and internal combustion engine, the method for operating an internal combustion engine with exhaust gas purification system, in which a rich mode of the internal combustion engine with a rich exhaust gas composition and a lean mode of the internal combustion engine with a lean exhaust gas composition are set alternately, and by the exhaust gas purification system with a rich exhaust gas composition ammonia is synthesized and stored and with a lean exhaust gas composition nitrogen oxides are reduced to form nitrogen by means of the stored ammonia. The quantity of fuel which is introduced by a combustion cycle of the internal combustion engine is introduced by at least one preinjection, at least one main injection and at least one afterinjection, the at least one preinjection and the at least one main injection are burnt under excess oxygen in order to generate a quantity of nitrogen oxides which is sufficient for the ammonia synthesis, and a rich or lean exhaust gas composition is set by the at least one afterinjection. The method may be used, for example, for exhaust gas purification in motor vehicle diesel engines.

Method for operating an internal combustion engine using exhaust gas purification system, and internal combustion engine

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 H S which is formed during the desulphating to be removed. When the internal combustion engine is in a desulphating operating mode, the following steps are performed: establishing a reducing exhaust gas composition upstream of the nitrogen oxide storage catalytic converter; releasing the sulphur which is bound in the nitrogen oxide storage catalytic converter, to form hydrogen sulphide (H S); feeding the hydrogen sulphide to an SCR catalytic converter which is arranged downstream of the nitrogen oxide storage catalytic converter in the exhaust-gas aftertreatment device; and reacting the hydrogen sulphide in the SCR catalytic converter to form sulphur dioxide under reducing exhaust-gas conditions. The method may be used in motor vehicles, e.g., passenger cars, with lean-burn internal combustion engines.

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.

Method and apparatus for desulfurizing a nitrogen oxide adsorber

A method for operating an exhaust-gas cleaning system having an NO adsorption accumulator and an SO trap, includes, in normal operating phases, feeding the exhaust gas to be cleaned first via the SO trap and then via the NO adsorption accumulator. The normal operating phases are from time to time interrupted by desulphurization phases for desulphurizing the SO trap. Means are provided for controlling the direction of flow of the exhaust stream so that it optionally passes firstly via the SO trap and then via the NO adsorption accumulator, or firstly via the NO adsorption accumulator and then via the SO trap, so that during the desulphurization phases the exhaust gas can be passed firstly via the NO adsorption accumulator and then via the SO trap.

Exhaust-gas cleaning system with nitrogen oxide accumulator catalyst and sulphur oxide trap and operating method therefor

A method and apparatus for purifying an exhaust gas of an internal combustion engine includes an ammonia generating catalyst for generating ammonia from nitrogen oxides contained in the exhaust gas to be purified, and a nitrogen oxide reducing catalyst downstream of the ammonia generating catalyst, for reduction of nitrogen oxides contained in the exhaust gas to be purified. Generated ammonia is used as the reducing agent. A nitrogen oxide adsorption catalyst is arranged upstream of the ammonia generating catalyst, or the ammonia generating catalyst is arranged in an exhaust pipe branch which pertains to only a part of several separately controllable internal-combustion sources. One or more additional exhaust pipe branches assigned to the other internal-combustion sources and lead to the nitrogen oxide reducing catalyst, while bypassing the ammonia generating catalyst. The part of the internal-combustion sources pertaining to the exhaust pipe branch of which contains the ammonia generating catalyst is operated either continuously or intermittently in a rich mode. Also, one or more combustion sources which feed their exhaust gas to the nitrogen oxide adsorption catalyst may be operated alternately in a lean and rich mode.

Exhaust gas purification process and apparatus with internal generation of ammonia for reducing nitrogen oxide

The invention relates to a method of operating a diesel engine having an engine controller which controls the operation of the diesel engine as a function of characteristic maps and permits rich/lean control of the diesel engine. The engine controller includes a computer which effects a changeover to rich or lean operation of the diesel engine as a function of predetermined changeover criteria, a sensor system which communicates with the computer and monitors parameters needed for changeover criteria, and a memory which communicates with the computer and in which the characteristic maps for operating the diesel engine are stored. The computer effects a changeover from lean to rich operation when all the changeover criteria in this respect are satisfied, and effects a change back from rich to lean operation when at least one of the changeover criteria in this respect is satisfied.

Method for running a diesel engine

A method for operating a multicylinder internal combustion engine with at least one adsorber catalytic converter in the exhaust line of the internal combustion engine includes operating the adsorber catalytic converter with periodically alternating adsorption and desorption operation. The exhaust leaving the adsorber catalytic converter in desorption operation is recycled and/or an oxidation catalytic converter is provided upstream of the adsorber catalytic converter. Exhaust recycling takes place occurs selectively in only one set of the cylinders of the internal combustion engine and this set of cylinders is operated in a state of incomplete combustion during desorption operation. Rich afterburning may be performed during desorption operation of the adsorber catalytic converter in the oxidation catalytic converter connected upstream and the oxidation catalytic converter is operated at an increased temperature during short regeneration phases to remove soot.

Method for operating a multicylinder internal combustion engine

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Stuttgart, Germany

Michel Weibel