Daimler Chrysler Ag

Dirk Voigtl&auml;nder

Andreas Hertzberg

Bernd Krutzsch

Michel Weibel

Josef G&uuml;nther

Christof Sch&ouml;n

G&uuml;nter Wenninger

Roland Kemmler

Carsten Plog

Walter Boegner

Thomas Stengel

Ralf Moos

Klaus Binder

Brigitte Konrad

Stefan Renfftlen

Rolf Wunsch

Marko Weirich

Norbert Ruzicka

Ralph Stetter

Heinz-Jost &Ouml;lschlegel

Armin H&uuml;rland

Kirsten Hardenberg

Doris Schr&ouml;der

G&uuml;nter Karl

Renate Marx

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.

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

A sensor for determining the concentration of sulphur compounds in a liquid includes: a working electrode in contact with the liquid to be analyzed; a referenced electrode insulated from the liquid to be analyzed; a liquid-impermeable membrane located between the working electrode and the reference electrode and permeable to an ion that may form a chemical compound with the sulphur compounds in the liquid to be analyzed; and a reference material in contact with the reference electrode or forms the reference electrode.

Sensor for determining the concentration of sulphur compounds in a liquid

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 and apparatus for periodically desulphating a nitrogen oxide or sulphur oxide storage vessel of an exhaust emission control system of a multi-cylinder internal combustion engine, in which an engine exhaust emission containing reducing agent and oxygen is fed to the nitrogen oxide or sulphur oxide storage vessel by setting a rich fuel/air ratio for a first subset of the engine cylinders and a fuel/air ratio which is, in comparison, leaner for the other cylinders. The distance between the fuel/air ratio for the first subset of the engine cylinders and that for the second subset of the engine cylinders is set higher in an initial storage vessel heating-up phase than in the subsequent desulphation mode, and/or control errors of the entire fuel/air ratio are eliminated by a predefinable set point value by modifying the fuel/air ratio either of just the first subset or just the second subset of the engine cylinders. Used, for example, in motor vehicles.

Method and device for periodically desulphating a nitrogen oxide or sulphur oxide storage vessel with rich/lean engine cylinder distribution

Growing community of inventors

Korntal-Münchingen, Germany

Dirk Voigtländer

Growing community of inventors

Korntal-Münchingen, Germany

Dirk Voigtl&auml;nder

Dirk Voigtländer