Abstract: The adherence to future legally obligatory exhaust gas limit values for diesel vehicles in Europe, North America and Japan requires not only the removal of particles but also effective removal of nitrogen oxides from the exhaust gas (‘deNOx’). The ‘active SCR process’ is the preferred method for this. The nitrogen oxide conversions achieved by means of this process are particularly high when an optimal NO2/NOx ratio, preferably 0.5, is set upstream of the SCR catalyst. The invention proposes a process which solves the problem of supplying NO2 in accordance with requirements by means of temperature control of the precatalyst which is decoupled from the operating state of the engine.

Abstract: To remove the nitrogen oxides from the exhaust gas from lean-burn engines, these engines are equipped with a nitrogen oxide storage catalyst, which has to be regenerated frequently by the engine being briefly switched to rich-burn mode. The regeneration is usually initiated when the nitrogen oxide concentration downstream of the catalyst rises above a permissible value. In this context, there is a risk of the bed temperature of the catalyst during and after regeneration being pushed into a range with incipient thermal desorption of the nitrogen oxides on account of the heat which is released during the conversion of the nitrogen oxides by the reducing constituents of the exhaust gas. This can lead to increased nitrogen oxide emission both during the regeneration itself and after the engine has been switched back to lean-burn mode.

Abstract: 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. The invention presents a process whose application allows the desulfurization temperature of conventional nitrogen oxide storage catalysts which comprise a platinum component and at least one nitrogen oxide storage material to be lowered. The basicity of the chemical environment of the platinum is lowered, while the nitrogen oxide storage material can remain unchanged as such.

Abstract: 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.

Abstract: Soot filters for removing soot from the exhaust gas of lean-burn engines become blocked with progressive operating duration on account of the deposition of soot, and must therefore be regenerated at regular intervals. It has been found that reliable operation of the soot filter is possible only if an active regeneration is carried out from time to time by increasing the exhaust-gas temperature to the soot ignition temperature. For this purpose, an oxidation catalytic converter is usually arranged upstream of the soot filter, and the exhaust-gas temperature is increased by means of the catalytic combustion of additionally injected fuel. Here, the oxidation catalytic converter is subjected to high temperature loading and therefore ages very quickly.

Abstract: 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.

Abstract: 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. The invention presents a process whose application allows the desulfurization temperature of conventional nitrogen oxide storage catalysts which comprise a platinum component and at least one nitrogen oxide storage material to be lowered. The basicity of the chemical environment of the platinum is lowered, while the nitrogen oxide storage material can remain unchanged as such.

Abstract: 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.

Abstract: Modern exhaust-gas purification systems in motor vehicles with a lean-burn engine include a starting catalyst fitted close to the engine and a main catalyst arranged in the underbody region, with both the starting catalyst and the main catalyst being formed by nitrogen oxide storage catalysts. The nitrogen oxide storage catalysts are in each case regenerated by the engine being briefly switched from lean-burn mode to rich-burn mode when the nitrogen oxide concentration in the exhaust gas downstream of the storage catalysts rises above a predetermined value. The starting catalyst is exposed to particularly high temperatures and is therefore prone to faster ageing of its nitrogen oxide storage capacity than the main catalyst.

Abstract: To remove the nitrogen oxides from the exhaust gas from lean-burn engines, these engines are equipped with a nitrogen oxide storage catalyst, which has to be regenerated frequently by the engine being briefly switched to rich-burn mode. The regeneration is usually initiated when the nitrogen oxide concentration downstream of the catalyst rises above a permissible value. In this context, there is a risk of the bed temperature of the catalyst during and after regeneration being pushed into a range with incipient thermal desorption of the nitrogen oxides on account of the heat which is released during the conversion of the nitrogen oxides by the reducing constituents of the exhaust gas. This can lead to increased nitrogen oxide emission both during the regeneration itself and after the engine has been switched back to lean-burn mode.

Abstract: Nitrogen oxide storage catalytic converters for purifying the exhaust gas of lean-burn engines are periodically regenerated by switching the engine from lean-burn mode to rich-burn mode. After regeneration has taken place, the engine is switched back to lean-burn mode. At this time, rich exhaust gas is still flowing in the exhaust line from the engine to the catalytic converter, which rich exhaust gas is ejected via the catalytic converter into the environment by the following, lean exhaust gas. This leads to brief emissions peaks of the rich exhaust gas constituents and impairs the level of exhaust gas cleaning which can be obtained. In order to solve said problem, it is proposed to create oxidizing conditions by injecting air upstream of the storage catalytic converter, so that the rich exhaust gas constituents still flowing in the exhaust line upstream of the storage catalytic converter can be converted at the storage catalytic converter to form non-harmful products.

Abstract: The fuel qualities for vehicles differ, for example, in Europe on a regional basis. This applies in particular to the sulphur content of the fuel. If vehicles with modern lean engines or with diesel engines which are equipped with nitrogen oxide storage-type catalytic converters in order to reduce the nitrogen oxide content in their exhaust gas pass through regions with a sulphur content in the fuel which is above the sulphur content which is specified for the vehicle, the engine controller will correspondingly frequently initiate desulphurization of the storage-type catalytic converter after the vehicle has been refuelled with this fuel. Any desulphurization entails an increased level of fuel consumption and greater ageing of the catalytic converter. It is proposed to avoid these adverse effects in that in lean motors the engine controller switches to stoichiometric operation in such a case, and in a diesel engine said engine controller prevents the desulphurization.

Abstract: A device for separating an imbricated formation (2) of continuously conveyed printing products (1) into a succession of spaced printing products (1), comprises a first conveyor (3) driven at a first velocity (v1), a second conveyor (4) arranged after the first conveyor (3) and driven at a second velocity (v2) which is higher in relation to the first velocity, and a de-imbricating device (5, 6) for accelerating the leading printing product (1) of the imbricated formation (2) to the second velocity (v2) and for maintaining the imbricated arrangement of the following printing products (1) being conveyed in the imbricated formation (2) at the first velocity (v1). The de-imbricating device comprises two suction belt conveyors (5, 6), the first suction belt conveyor (5) driven at the first velocity (v1), that the second suction belt conveyor (6) is driven at the second velocity (v2).

Abstract: A catalyst for purifying exhaust gases of a diesel engine. The catalyst contains two functional layers superimposed on an inert supporting body, whereby the first layer, which is situated directly on the supporting body, has a nitrogen oxide storage function and the second layer, which is in direct contact with the exhaust gas, has a catalytic function. The second functional layer additionally has a hydrocarbon-storage function and its catalytic function is provided by catalytically active noble metals of the platinum group which are deposited in highly dispersed form on finely divided, acidic carrier materials. Nitrogen oxides in the oxygen-rich exhaust gas of a diesel engine can be converted with optimal utilization of the reductive constituents contained in the exhaust gas. For this purpose, no reducing agents going beyond the reductive components (carbon monoxide and hydrocarbons) which are contained as a consequence of incomplete combustion need to be added to the exhaust gas.

Abstract: A shell component for an aircraft fuselage includes a fuselage skin panel, a plurality of stringers extending in an aircraft lengthwise direction, and a plurality of frames extending crosswise relative to the stringers. The stringers and the frames are respectively welded onto the skin panel with the addition of a weld filler material. Each frame includes a frame root portion and a frame profile portion connected to each other. The frame root portion has cut-out notches receiving the stringers passing therethrough. The frame root portion is welded to the skin panel at the areas between the cut-out notches, and may be welded to the respective stringer in each cut-out notch. The stringers and frames are fabricated from webs and flanges, whereby a premanufactured grid of flanges may be used. The result is a very strong, yet simple shell component structure, that may be manufactured with a simple welding process, at a low cost and with low effort.

Abstract: A composition for cleaning or caring for the skin, teeth or hair or for cleaning smooth surfaces in described, which has an aqueous phase containing a pregelatinized, crosslinked starch selected from a C2-C5 hydroxyalkyl starch and a C2-C18 acyl starch. Preference is given to hydroxypropyl di-starch phosphate or di-starch C4-C18-alkanoate or alkenoate. The starch acts 1) as a stability improver, 2) as a viscosity regulator, 3) as a (co)emulsifier, 4) as a skin feel improving agent and 5) as an agent for improving hairdressing characteristics.

Abstract: A catalyst system for the treatment of exhaust gases from a diesel engine includes a first and a second catalyst reducing catalyst arranged in series in an exhaust gas treatment system. The first catalyst is located near the engine in a region of the exhaust gas treatment system in which the exhaust gas temperature reaches temperatures of more than 200° C. under full engine load. The second catalyst is located further from the engine in a region of the exhaust gas treatment system in which the exhaust gas temperature reaches a maximum of 500° C. under full engine load. The maximum nitrogen oxides reduction in the first catalyst takes place at a lower temperature than the maximum nitrogen oxides reduction in the second catalyst.