Abstract: In an internal combustion engine having at least one cylinder with a combustion chamber formed between a piston and a cylinder head, inlet and outlet ducts formed in the cylinder head, a fuel injector arranged in the cylinder head into for forming a hollow fuel cone in the combustion chamber and a spark plug arranged such that, during The injection of fuel, the electrodes of the spark plug are outside the injected hollow fuel cone, the spark plug and the fuel injector are positioned in such a way that a first distance (C) is provided between an injector axis and a free end of the central electrode of the spark plug, and the cylinder bore has a diameter (D), with a ratio (C/D) of the first distance (C) and a bore diameter (D) being in a range of 0.1 to 0.19, in particular 0.13 to 0.17.

Abstract: In an internal combustion engine having at least one cylinder with a combustion chamber formed between a piston and a cylinder head, at least one inlet duct and at least one outlet duct formed in the cylinder head, a fuel injector arranged in the cylinder head so as to project into the combustion chamber and having an outwardly opening injection nozzle through which fuel in the form of a hollow cone is injected into the combustion chamber and a spark plug arranged in the combustion chamber in such a way that, during the injection of fuel, the electrodes of the spark plug are outside the injected hollow cone of fuel, the spark plug and the fuel injector are positioned in such a way that a first distance (c) is provided between an injector axis and a free end section of the central electrode of the spark plug, and the cylinder bore has a diameter (D), with a ratio (C/D) of the first distance (C) and a bore diameter (D) being in a range of 0.1 to 0.19, in particular 0.13 to 0.17.

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: 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.

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 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.

Abstract: An exhaust-gas cleaning system removes at least nitrogen oxides contained in exhaust-gas from a combustion source. An ammonia-generation catalytic converter generates ammonia using constituents of at least some of the exhaust gas emitted from the combustion source during ammonia-generation operating phases. Downstream a nitrogen oxide reduction catalytic converter reduces nitrogen oxides which are contained in the exhaust gas emitted from the combustion source using the ammonia generated as reducing agent. A nitrogen monoxide generation unit is situated outside the combustion source, for enriching the exhaust gas which is fed to the ammonia-generation catalytic converter with generated nitrogen monoxide during the ammonia-generation operating phases. The system is used for cleaning exhaust gases of motor vehicle internal-combustion engines which are operated predominantly in lean-burn mode, removing nitrogen oxides which are contained therein.

Abstract: In a method for the periodic desulphurization of a nitrogen-oxide or sulphur-oxide accumulator of an exhaust-gas cleaning system of an internal-combustion engine, during respective desulphurization periods, the accumulator is fed secondary air by secondary-air supply means, and is fed an engine exhaust gas which contains a reducing agent by setting a rich engine air ratio. At least during part of the desulphurization period, after a predeterminable desulphurization temperature has been reached, the accumulator air ratio is set, by suitably alternating the secondary air quantity supplied and/or the engine air ratio, between an oxidizing or stoichiometric atmosphere, and a reducing atmosphere.

Abstract: In a method for identifying the state of an NOx storage catalyst which is cyclically loaded with NOx in the exhaust stream of an internal combustion engine and regenerated, two electrical defining quantities, independent of each other, of the electrically complex impedance of the NOx storage catalyst are detected, one of the two electrical quantities being a measure of the degree of loading of the NOx storage catalyst, and from the second electrical quantity the point in time being identifiable for the end of the regeneration process of the NOx storage catalyst.

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 solid material for adsorption of nitrogen oxides in an oxidizing atmosphere and desorption of nitrogen oxides in a reducing atmosphere in gases, such as internal combustion engine exhaust gases, can comprise a porous support, at least one metal component, and at least one transition metal component. A process for adsorption and desorption of nitrogen oxides in gases, such as internal combustion engine exhaust gases, can comprise the use of at least one solid material.

Abstract: In a method for identifying the state of an NOx storage catalyst which is cyclically loaded with NOx in the exhaust stream of an internal combustion engine and regenerated, two electrical defining quantities, independent of each other, of the electrically complex impedance of the NOx storage catalyst are detected, one of the two electrical quantities being a measure of the degree of loading of the NOx storage catalyst, and from the second electrical quantity the point in time being identifiable for the end of the regeneration process of the NOx storage catalyst.

Abstract: 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.

Abstract: An internal-combustion engine includes an engine control system that permits a change-over between a lean operation and a rich operation of the internal-combustion engine, and an exhaust gas purification system. A &lgr;-probe, an SOx storage catalyst and an NOx storage catalyst are successively arranged in an exhaust gas line behind the engine. At the start of desulfurization of the SOx storage catalyst, a change-over takes place from the lean to the rich operation of the engine. Secondary air is fed into the exhaust gas line; a predetermined &lgr; value of the exhaust gases mixed with secondary air and a temperature in the SOx storage catalyst are measured. At the end of the desulfurization, a change-over takes place from the rich to a lean operation of the engine.

Abstract: 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.

Abstract: A method of cleaning an exhaust gas from a combustion system that is operated alternately in lean and rich conditions includes intermediately storing nitrogen oxides during lean operation; releasing the stored nitrogen oxides, thereby producing ammonia and storing the ammonia during rich operation; releasing the ammonia, thereby reducing nitrogen oxides in a subsequent lean condition.

Abstract: An emission control system for an internal-combustion engine has at least one nitrogen oxide adsorber for the periodic adsorption and desorption of nitrogen oxides contained in the exhaust gas of the internal-combustion engine. A desorption gas pipe has an externally heatable catalyst arranged therein to which a mixture of air and/or exhaust gas can be fed as well as fuel at an at least stoichiometric proportion. This mixture is burned to form a desorbing gas flow which is fed to the respective nitrogen oxide adsorber for the nitrogen oxide desorption.

Abstract: An internal-combustion engine system includes an internal-combustion engine with a pertaining engine exhaust gas system, an emissions control device having an NO.sub.x storage catalyst arranged in the exhaust gas system, a lambda probe for detecting the engine air ratio and devices for the periodic desulfurization of the catalyst at a raised temperature and a rich air ratio of the latter, as well as to an operating process suitable for this system. The desulfurization devices comprise secondary air feeding devices for feeding secondary air into the NO.sub.x storage catalyst. During the desulfurization phases, the engine is operated at a rich air ratio and secondary air is metered into the catalyst.

Abstract: An internal-combustion engine includes an engine control system that permits a change-over between a lean operation and a rich operation of the internal-combustion engine, and an exhaust gas purification system. A .lambda.-probe, an SO.sub.x storage catalyst and an NO.sub.x storage catalyst are successively arranged in an exhaust gas line behind the engine. At the start of desulfurization of the SO.sub.x storage catalyst, a change-over takes place from the lean to the rich operation of the engine. Secondary air is fed into the exhaust gas line; a predetermined .lambda. value of the exhaust gases mixed with secondary air and a temperature in the SO.sub.x storage catalyst are measured. At the end of the desulfurization, a change-over takes place from the rich to a lean operation of the engine.

Abstract: 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.