Abstract: 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.

Abstract: A method for operating a particle filter that filters particles contained in the exhaust of motor vehicle combustion engines. A conditioning step is performed such that the separation efficiency of the particle filter for particles is increased relative to the value existing in the new condition.

Abstract: A method for operating a particle filter that filters particles contained in the exhaust of motor vehicle combustion engines. A conditioning step is performed such that the separation efficiency of the particle filter for particles is increased relative to the value existing in the new condition.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: An exhaust gas aftertreatment installment and associated exchaust 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.

Abstract: 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.

Abstract: 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 NO2 from exhaust gas. This NO2 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 NO2 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.

Abstract: In a method for operating an internal combustion engine with direct fuel injection, the fuel injection includes at least two injections that are carried out at at least two different injection pressures.

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 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 NO2 from exhaust gas. This NO2 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 NO2 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.

Abstract: In a method for operating an internal combustion engine with direct fuel injection, the fuel injection includes at least two injections that are carried out at at least two different injection pressures.

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: 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: A multi-cylinder air-compressing injection-type internal-combustion engine having a nitric oxide adsorber catalyst and an exhaust gas return device. In order to increase the hydrocarbon fraction in the exhaust gas in front of an exhaust gas aftertreatment device during a regeneration phase and to reduce the oxygen content, exhaust gas pipes of the cylinders are divided into at least two flows, which extend separately from one another at least along a distance. An increased hydrocarbon emission is generated exclusively in the cylinders of one of the flows at times. Another of the flows is connected by way of the exhaust gas return device with an air intake pipe of the internal-combustion engine.

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.