Daimler Chrysler Ag

Daimlerchrylser Ag

Josef G&uuml;nther

Bernd Krutzsch

Michel Weibel

Andreas Hertzberg

Stefan Renfftlen

Dirk Voigtl&auml;nder

G&uuml;nter Wenninger

Christof Sch&ouml;n

Walter Boegner

Klaus Binder

Brigitte Konrad

Rolf Wunsch

Marko Weirich

Herbert Klein

Ralph Stetter

Hans-Peter Holzt

Dirk Voightl&auml;nder

Dieter Langrock

Heinz-Jost &Ouml;lschlegel

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 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 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

In a multi-cylinder internal combustion engine having at least two cylinder banks each with an exhaust system including a catalytic converter, wherein one of the cylinder banks can be deactivated when the engine operates only under partial load, the exhaust systems have exhaust pipe sections which are interconnected by a cross-over structure disposed upstream of the catalytic converters so that exhaust gas can flow also through the catalytic converter of the deactivated cylinder bank, and a length compensating element is disposed in at least one of the exhaust pipe sections and the cross-over structure.

Internal combustion engine with at least two cylinder banks

Growing community of inventors

Affalterbach, Germany

Josef Günther

Growing community of inventors

Affalterbach, Germany

Josef G&uuml;nther

Josef Günther