Daimler Chrysler Ag

Daimler Ag

Andreas Hertzberg

Bernd Krutzsch

Michel Weibel

Stefan Renfftlen

Rolf Wunsch

Markus Paule

Guenter Wenninger

Arno Nolte

Norbert Waldbuesser

Brigitte Bandl-Konrad

Dirk Voigtl&auml;nder

Walter Boegner

Klaus Binder

Brigitte Konrad

Marko Weirich

Josef G&uuml;nther

G&uuml;nter Wenninger

Christof Sch&ouml;n

Dirk Voigtländer

Christian Enderle

Guido Vent

Klaus Roessler

Charles Robert Koch

Klaus R&ouml;ssler

Günter Wenninger

Norbert Ruzicka

Ralph Stetter

Andreas Biemelt

Heinz-Jost Ölschlegel

Bernd Bauer

Heinz-Jost &Ouml;lschlegel

Kirsten Hardenberg

Doris Schr&ouml;der

G&uuml;nter Karl

Josef Günther

Renate Marx

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

In a method of operating a particle filter in an exhaust system of a motor vehicle internal combustion engine, wherein the particle filter is reconditioned, in intervals, by a soot-burn-off procedure, the amount of noncombustible ashes also collected in the particle filter is reduced by heating the particle filter and supplying to the particle filter, together with the exhaust gas of the internal combustion engine, a reducing agent which reacts with the ash deposits so as to chemically convert the ash deposits such that at least non-metallic ash components are decomposed and carried out of the particle filter by the exhaust gas.

Method of operating a particle filter in the exhaust system of a motor vehicle's internal combustion engine

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 emission control system having a nitrogen oxide adsorber and a desulfating device, and a method for desulfating a nitrogen oxide absorber are disclosed. The desulfating device is managed so as to establish an oscillatingly rich and lean exhaust gas composition during a respective desulfating operation, and contains an oxygen accumulator downstream from the nitrogen oxide adsorber. The nitrogen oxide adsorber is effectively desulfated by way of a corresponding desulfating method, and released sulfur compounds are thereby simultaneously oxidized. The exhaust emission control systems can be utilized, for example, with a motor vehicle internal combustion engine.

Exhaust emission control system having a nitrogen oxide adsorber and method for desulfating the nitrogen oxide adsorber

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.

In a method for operating an emission control system having nitrogen oxide storage, for cleaning up a nitrogen oxide-containing, sulfur-contaminated exhaust gas from combustion equipment, from time to time desulfating phases are performed for releasing sulfur intercalated in the nitrogen oxide storage. Two desulfating modes are provided, namely, a main desulfating mode for substantially completely desulfating the nitrogen oxide storage and a partial desulfating mode for partially desulfating same, a lower nitrogen oxide storage minimum temperature and a shorter desulfating target duration being predefined for the partial desulfating processes than for the main desulfating processes. The method may be used, for example, in emission control systems of predominantly lean-combustion operated Otto engines of motor vehicles.

Method for operating an emission control system having nitrogen oxide storage

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 of operating an exhaust-emission control system with a nitrogen oxide adsorber and a loading sensor includes alternately operating the nitrogen oxide adsorber in adsorption phases with an at least stoichiometric exhaust air ratio and in regeneration phases with an at most stoichiometric exhaust air ratio. The loading sensor is able to ascertain continuously the nitrogen oxide loading of the adsorber even during the regeneration phases. By suitable evaluation of the loading sensor signal, the time for a changeover from an adsorption phase to a desorption phase and vice versa is determined. In addition, the storage capacity of the adsorber at a given time, when desulphating of the adsorber should take place, and whether the desulphating effect achieved was adequate, are determined.

Method of operating an exhaust-emission control system with a nitrogen oxide adsorber and a loading sensor

In a method for operating a spark ignition engine with direct fuel injection, in which the engine is operated either with charge stratification or with a homogeneous charge, the open and/or closed positions of the inlet and exhaust valves are controlled with variable timing depending on the engine operating condition. The timings are determined on the basis of basic timing settings, which are provided in basic timing performance graphs for operation with charge stratification and homogeneous charge operation. The basic timing settings are modified by means of correction values to raise the temperature of the exhaust gas for internal exhaust-gas recirculation and for causing a movement of the charge in the cylinders.

Method for operating a spark ignition engine with direct fuel injection

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

A method reduces harmful exhaust-gas emissions of a spark-ignition, direct fuel injection engine operated with a lean fuel/air mixture. Under part load, the engine is operated in the stratified-charge mode with a &lgr; value of >1, and to reduce nitrogen oxides adsorbed on a catalyst, a jump to a homogeneous mode with air ratios of lambda <1 is carried out at specific intervals by throttling of the air quantity supplied and/or by an increase in the fuel injection quantity. In a first step, the air quantity in the combustion space is reduced by changes in the valve control times and, in a second step, a transition is made from the stratified-charge mode to the homogeneous mode, with a &lgr; value of less than 1 being set.

Method for reducing harmful exhaust gas emissions of a spark-ignition engine operating with a lean fuel/air mixture

A direct-injection Otto cycle internal-combustion engines can be operated in the stratified charge mode with a later fuel injection during the compression cycle and a lean mixture formation and, with an operating mode with a homogeneous mixture formation, by fuel injection during the intake cycle which is provided for higher load ranges of the internal-combustion engine. The exhaust gases of the internal-combustion engine are decontaminated by an NO,storage catalyst which must be periodically regenerated during a homogeneous mixture formation and at rich fuel/air ratios (&lgr;). To permit a fast change of the operating mode and particularly the regeneration of the storage catalyst without changing the running performance of the internal-combustion engine, the fuel quantity to be injected per power cycle, is apportioned during a homogeneous operating phase during the change of operating modes, corresponding to the actual intake air flow rate by adjusting the respective injection time. Isochronously and proportionally to the change of the injection time, the ignition point in time is adjusted in the direction of a late ignition. The homogeneous operating phase is limited by a change-over point in time at which the injection end of the fuel injection is shifted into the power cycle provided for the demanded operating mode.

Method for changing the operating mode of a direct-injection otto cycle internal-combustion engine

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Markgroeningen, Germany

Andreas Hertzberg