Patent application number | Description | Published |
20100037597 | EXHAUST EMISSION CONTROL SYSTEM FOR LEAN ENGINES AND METHOD FOR OPERATING THE SYSTEM - An emission control system for the cleaning of the exhaust gases of a lean burn engine with two or more cylinders comprises a first exhaust leg for the exhaust gases of a first group of cylinders and a second exhaust leg for the exhaust gases of a second group of cylinders. A nitrogen oxide storage catalyst is arranged in each exhaust leg. The two exhaust legs are combined downstream of the storage catalysts at a confluence to form a common exhaust leg. The common exhaust leg contains an SCR catalyst. The first and second groups of cylinders are each supplied alternately in periodic intervals with lean and rich air/fuel mixtures. Lean or rich exhaust gases are thus obtained in the combustion in the cylinders and released into the corresponding exhaust legs. Lean and rich exhaust gases are adjusted with respect to one another so as to result in a lean exhaust gas after the combination of the exhaust gases in the common exhaust leg. The regeneration of the storage catalysts may result in the formation of ammonia, which is stored by the SCR catalyst and reacted with nitrogen oxides which pass through the storage catalysts in an unwanted manner during the storage phases. | 02-18-2010 |
20100055012 | NITROGEN OXIDE STORAGE CATALYST FEATURING A REDUCED DESULFURIZATION TEMPERATURE - Nitrogen oxide storage catalysts are used to remove nitrogen oxides from the exhaust gas of internal combustion engines operated predominantly under lean burn conditions. When these catalysts are used in diesel vehicles, the increased sulfur content in the fuel during operation results in poisoning of the catalyst, which is reversible at high temperatures under reduced exhaust gas conditions. In the case of conventional nitrogen oxide storage catalysts, temperatures of more than 600° C. have to be obtained for desulfurization. This is not always possible in diesel vehicles with a nitrogen oxide storage catalyst in the underbody area. | 03-04-2010 |
20100064665 | METHOD AND DESULFURIZING NITROGEN OXIDE STORAGE CATALYSTS IN THE EXHAUST GAS SYSTEM OF A LEAN MIX ENGINE - Lean burn engines require an exhaust gas system comprising nitrogen oxide storage catalysts for removal of nitrogen oxides from their exhaust gases. When the lean burn engine is operated with a sulphur-containing exhaust gas, the storage catalysts have to be desulphurized from time to time. During the desulphurization, there is the risk of high pollutant emissions. These emissions can be reduced when the cylinders of the lean burn engine are combined in two groups which release their exhaust gas to two assigned exhaust legs, in each of which is arranged at least one nitrogen oxide storage catalyst. The two exhaust legs are combined beyond the storage catalysts to form a common exhaust leg which contains a catalyst which possesses a three-way function under stoichiometric conditions. The two nitrogen oxide storage catalysts are desulphurized offset in time with respect to one another. While rich exhaust gas at a high temperature flows through one storage catalyst for desulphurization, lean exhaust gas flows through the second storage catalyst, in such a way that the combined exhaust gas is of stoichiometric composition over the entire desulphurization period. Under the stoichiometric conditions, the catalyst with three-way function is capable of converting hydrocarbons, carbon monoxide and nitrogen oxides to harmless components. | 03-18-2010 |
20100101210 | Method for Regenerating Soot Filters in the Exhaust Gas System of a Lean Mix Engine, and Exhaust Gas System Therefor - To adhere to legal exhaust-gas regulations, the exhaust gases of a lean-burn engine must be freed from soot particles and nitrogen oxides. It is proposed that the cylinders of the lean-burn engine be divided into two groups which discharge their exhaust gases into two associated exhaust lines which each comprise a soot filter and which are merged at an opening-in point into a common exhaust line. The common exhaust line comprises the catalytic converter for the removal of the nitrogen oxides. By regenerating the two soot filters at different times, the exhaust-gas temperature in the common exhaust line is limited to a mean temperature between the exhaust-gas temperature of normal operation and that of regeneration operation, and the catalytic converter for the removal of the nitrogen oxides is preserved. | 04-29-2010 |
20100233051 | NITROGEN OXIDE STORAGE CATALYST FEATURING A REDUCED DESULFURIZATION TEMPERATURE - Nitrogen oxide storage catalysts are used to remove nitrogen oxides from the exhaust gas of internal combustion engines operated predominantly under lean burn conditions. When these catalysts are used in diesel vehicles, the increased sulfur content in the fuel during operation results in poisoning of the catalyst, which is reversible at high temperatures under reduced exhaust gas conditions. In the case of conventional nitrogen oxide storage catalysts, temperatures of more than 600° C. have to be obtained for desulfurization. This is not always possible in diesel vehicles with a nitrogen oxide storage catalyst in the underbody area. | 09-16-2010 |
20100300077 | DUAL-STAGE METHOD FOR THE REACTIVATION OF THERMALLY AGED NITROGEN OXIDE STORAGE CATALYSTS - Nitrogen oxide storage catalysts are used to remove the nitrogen oxides present in the lean exhaust gas of lean-burn engines. As a result of the stress due to high temperatures in vehicle operation, they are subject to thermal aging processes which affect both the nitrogen oxide storage components and the noble metals present as catalytically active components. | 12-02-2010 |
20110258982 | METHOD FOR THE ON-BOARD REACTIVATION OF THERMALLY AGED NITROGEN OXIDE STORAGE CATALYSTS IN MOTOR VEHICLES HAVING AN INTERNAL COMBUSTION ENGINE OPERATED PREDOMINANTLY UNDER LEAN CONDITIONS - Nitrogen oxide storage catalysts are used to remove the nitrogen oxides present in the lean exhaust gas of lean-burn engines. Storage catalysts are thermally aged by high temperatures. Ageing is due to sintering of the catalytically active noble metal components of the catalyst and to formation of compounds of the storage components with the support materials. According to the invention, the formation of compounds of the storage materials can be largely reversed by treatment of the storage material with a gas mixture containing carbon dioxide, optionally water vapor and optionally nitrogen oxides at temperatures in the range from 200° C. to 950° C., preferably from 300° C. to 700° C. The reactivation can be carried out under emission-neutral conditions directly in the vehicle during driving operation by setting of suitable exhaust gas conditions and regulating the air/fuel ratio. | 10-27-2011 |
20110271658 | NITROGEN OXIDE STORAGE CATALYTIC CONVERTER FOR USE IN A MOTOR VEHICLE IN A CLOSE-COUPLED POSITION - The use of nitrogen oxide storage catalysts in a close-coupled position for the cleaning of the exhaust gases from gasoline engines with direct gasoline injection which are operated with a predominantly lean air/fuel mixture places particular demands on the thermal stability and aging stability of the catalysts to be used. | 11-10-2011 |
20110277450 | REGULATING STRATEGY FOR A CATALYTIC CONVERTER CONCEPT FOR EXHAUST-GAS AFTERTREATMENT HAVING A PLURALITY OF NITROGEN OXIDE STORAGE CATALYTIC CONVERTERS - The present invention relates to a regulating strategy for a special catalytic converter for exhaust-gas aftertreatment. The catalytic converter concept is distinguished in that at least two nitrogen oxide storage catalytic converters are used in the exhaust section of a vehicle. The first, possibly close-coupled unit is followed by one or more nitrogen oxide storage catalytic converters, which are possibly situated in the underbody of the vehicle. The nitrogen oxide storage catalytic converters are then regenerated as a function of the exceedance of nitrogen oxide threshold vales downstream thereof. | 11-17-2011 |
20120148464 | EXHAUST-GAS AFTERTREATMENT SYSTEM WITH CATALYTICALLY ACTIVE WALL-FLOW FILTER WITH STORAGE FUNCTION UPSTREAM OF CATALYTIC CONVERTER WITH IDENTICAL STORAGE FUNCTION - The present invention relates to an exhaust-gas aftertreatment system which comprises a preferably catalytically active particle filter (wall-flow filter) which is followed in turn by a throughflow monolith (flow-through monolith) which is preferably provided with a catalytically active function. Both components have the same storage functions for gaseous substances present in the exhaust gas of internal combustion engines. The system is suitable in particular for the simultaneous removal of particles and pollutants from the exhaust gas of both predominantly lean-operated internal combustion engines and also of internal combustion engines operated predominantly with a stoichiometric air/fuel mixture. Likewise described is a process for the production and the use of such a system for exhaust-gas aftertreatment. | 06-14-2012 |
20130028818 | METHOD OF DEPLETING NITROUS OXIDE IN EXHAUST GAS AFTER-TREATMENT FOR LEAN-BURN ENGINES - The present invention relates to a method for exhaust gas after-treatment for essentially lean-burn internal combustion engines and also a corresponding advantageous exhaust gas after-treatment system. In particular, the present invention relates to reducing the proportion of the greenhouse gas N20 in the total exhaust gas from a corresponding internal combustion system using at least one NOx storage catalyst as exhaust gas purification element. The objective of the invention is to operate the N20 depletion catalyst located downstream of the NOx storage catalyst under lambda=<1 conditions when the N20 formed by the NOx storage catalyst reaches the N20 depletion catalyst. | 01-31-2013 |
20140090362 | METHOD FOR REGENERATING NOX STORAGE CATALYTIC CONVERTERS OF DIESEL ENGINES WITH LOW-PRESSURE EGR - The invention relates to a method for regenerating nitrogen oxide storage catalytic converters and to a correspondingly adapted exhaust-gas purification system for lean-burn engines. In particular, the present invention relates to the regeneration of nitrogen oxide storage catalytic converters during special driving situations of the vehicle. | 04-03-2014 |
20140123630 | Method and Device for Reactivating Exhaust-Gas Purification Systems of Diesel Engines with Low-Pressure EGR - The invention relates to a method for reactivating a system composed of an oxidation catalytic converter ( | 05-08-2014 |