Abstract: Nitrogen oxide storage catalysts are used for removing the nitrogen oxides present in the lean-burn exhaust gas of lean-burn engines. Here, the purifying action is based on the nitrogen oxides being stored in the form of nitrates by the storage material of the storage catalyst during a lean-burn operating phase of the engine and the previously formed nitrates being decomposed in a subsequent rich-burn operating phase of the engine and the nitrogen oxides which are being liberated again being reacted with the reducing exhaust gas constituents over the storage catalyst to form nitrogen, carbon dioxide and water. Storage catalysts are thermally aged by high temperatures. The aging 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.

Abstract: A nitrogen oxide storage material which is based on storage compounds of elements selected from the group consisting of magnesium, calcium, strontium, barium, the alkali metals, the rare earth metals and mixtures thereof and has a homogeneous magnesium-aluminium mixed oxide doped with cerium oxide as support material for the storage compounds is described. Nitrogen oxide storage catalysts using this storage material display a broad working range, a high storage efficiency and good ageing resistance.

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: When a nitrogen oxide storage catalyst is being regenerated, the regeneration may be terminated for example as a result of a premature load change in the engine, which can lead to incomplete emptying of the storage catalyst. The residual filling level which remains in the catalyst following an incomplete regeneration of this nature is used as the starting value for calculation of the filling level during the next storage phase. After incomplete regeneration, the nitrogen oxide conversion rate is initially greater than would be expected, on account of the residual filling level. By taking this increased conversion rate into account when calculating the filling level during the storage phase, it is possible to further improve the accuracy of the calculation.

Abstract: A method for the desulfurization of an NOx storage catalyst arranged in an exhaust system of an internal combustion engine, whereby, for the desulfurization, the internal combustion engine is alternatingly operated in a lean mode at ?>1 and a rich mode at ?<1. During the desulfurization process, the present invention provides for the progress of the desulfurization being monitored, using a change in a parameter relating to intervals (In), whereby the interval (In) lasts from the beginning of an nth rich operating phase (Tf,n), until the measured value drops below a predetermined lambda threshold value (Sf) downstream from the NOx storage catalyst (16). Furthermore, the progress of the desulfurization is monitored, using a change in a lambda probe voltage (Un) downstream from the NOx storage catalyst (16), which is determined at the end of a predetermined interval at the beginning of an nth rich operating phase (Tf,n).

Abstract: The invention relates to a catalyst for lowering the amount of NOx in the lean exhaust gas from lean burn engines, comprising active aluminum oxide, magnesium oxide and at least one noble metal of the platinum group of the periodic table of the elements, as well as at least one nitrogen oxide storage material. The catalyst is characterized in that the magnesium oxide forms a homogeneous mixed oxide with aluminum oxide and is present in a concentration of about 1 to about 40 wt.-%, based on the total weight of the mixed oxide.

Abstract: The present invention provides processes for checking the operability of a nitrogen oxide storage catalyst during operation of a lean burn engine. The processes of the present invention utilize a nitrogen oxide storage material, a catalytically active component and optionally an oxygen storage material. During lean burn engine operation, damage to the catalytically active components is detected if the nitrogen oxide storage capacity in the kinetically controlled temperature range is lowered and damage to the storage material is detected if the nitrogen oxide storage capacity is lowered in the thermodynamically controlled temperature range.

Abstract: An easily producible and easily installable ignition mechanism for restraint devices in a vehicle includes an ignition capsule, in which at least one ignition element and its contact pins are fixed. Into the ignition capsule a pedestal can be set, in which a carrier arrangement having circuit elements is arranged. Spring elements are present, by which contact is established between circuit elements and contact pins of the ignition element when the pedestal is set into the ignition capsule.

Abstract: The invention relates to a substrate board (2) for micro hybrid integrated circuits (7) having a ceramic body (3). According to the present invention, provision is made that the ceramic body (3) is a porous body, whose cavities are filled with aluminum. Due to the relatively small difference in thermal expansion coefficients of the substrate board (2) and the micro hybrid integrated circuit (7), a very good thermal bond of the micro hybrid integrated circuits (7) to the substrate board (2) is possible.

Abstract: A method for producing a nitrogen oxide storage material that contains at least one storage component in the form of particles of an oxide, carbonate or hydroxide of the elements magnesium, strontium, barium, lanthanum and cerium on a carrier material from the group consisting of doped cerium oxide, cerium/zirconium mixed oxide and aluminum oxide or mixtures of these. The method is carried out by suspending the support material in an aqueous solution of precursors of the storage components, this suspension is then introduced into a hot gas stream, the temperature of which is calculated so that, during a residence time of the suspension in the hot gas stream of less than one minute, the solvent of the suspension is evaporated out and the precursors of the storage components are thermally broken down and converted to the storage components before the storage material that forms in this way is separated from the stream of hot gases.

Abstract: The present invention relates to a method for the desulfurization of an NOx storage catalyst situated in an exhaust system of an internal combustion engine, whereby, for the desulfurization, the internal combustion engine is alternatingly operated in a lean mode at &lgr;>1 and a rich mode at &lgr;<1. During the desulfurization process, the present invention provides for the progress of the desulfurization being monitored, using a change in a parameter relating to intervals (In), whereby the interval (In) lasts from the beginning of an nth rich operating phase (Tf,n), until the measured value drops below a predetermined lambda threshold value (Sf) downstream from the NOx storage catalyst (16). Furthermore, the progress of the desulfurization is monitored, using a change in a lambda probe voltage (Un) downstream from the NOx storage catalyst (16), which is determined at the end of a predetermined interval at the beginning of an nth rich operating phase (Tf,n).

Abstract: A process for removing soot from the exhaust gas of a diesel engine by oxidizing the nitrogen monoxide present in the exhaust gas to nitrogen dioxide, separating the soot from the exhaust gas stream and oxidizing the soot using the nitrogen dioxide produced. The process is performed in at least two consecutive process stages and the soot is separated from the exhaust gas stream with an efficiency W between 0.05 and 0.95 in each process stage, wherein each process stage can be assigned a transmission for soot in accordance with T=1−W and the total transmission of the process for soot is given as the product of the transmissions of all the process stages.

Abstract: A powdered catalyst material based on aluminum oxide, which contains at least one basic metal oxide and at least one noble metal from the platinum group of the Periodic Table of Elements in addition to aluminum oxide. The catalyst material is obtainable by loading a support material already stabilized by basic oxides by renewed impregnation with further basic oxides. After drying and calcining this post-impregnated material at temperatures below 800° C., the catalytically active noble metals are also incorporated into the support material by impregnation.

Abstract: A nitrogen oxide storage catalyst which contains at least one catalyst material and at least one nitrogen oxide storage component from the group of alkali and alkaline earth metals. The nitrogen oxide storage component, after completing catalyst preparation, is present as finely divided barium sulfate, strontium sulfate, a mixture or mixed crystals of the two sulfates, or as their complete or incomplete decomposition product with an average particle size of less than 1 &mgr;m. Barium sulfate and/or strontium sulfate act as feed materials for the active storage component in the storage catalyst according to the invention. As a result of the reductive exhaust gas compositions occurring under normal automobile driving conditions barium sulfate and strontium sulfate decompose to compounds which are able to store nitrogen oxides. This compensates for the loss of active storage components which occurs due to aging.

Abstract: A nitrogen oxide storage material is disclosed which contains at least one storage component for nitrogen oxides in the form of an oxide, mixed oxide, carbonate or hydroxide of the alkaline earth metals magnesium, calcium, strontium and barium and the alkali metals potassium and caesium on a high surface area support material. The support material can be doped cerium oxide, cerium/zirconium mixed oxide, calcium titanate, strontium titanate, barium titanate, barium stannate, barium zirconate, magnesium oxide, lanthanum oxide, praseodymium oxide, samarium oxide, neodymium oxide, yttrium oxide, zirconium silicate, yttrium barium cuprate, lead titanate, tin titanate, bismuth titanate, lanthanum cobaltate, lanthanum manganate and barium cuprate or mixtures thereof.

Abstract: A sulfur oxide storage material contains a magnesium-aluminum spinel (MgO.Al2O3) and can be used as a so-called “sulfur trap” to remove sulfur oxides from oxygen-containing exhaust gases of industrial processes. In particular, it can be used for the catalytic purification of exhaust gas from internal-combustion engines to remove the sulfur oxides from the exhaust gas in order to protect the exhaust gas catalysts from sulfur poisoning. The material displays a molar ratio of magnesium oxide to aluminum oxide in the range of over 1.1:1, and the magnesium oxide present in stoichiometric excess is homogeneously distributed in a highly disperse form in the storage material.

Abstract: A process for evaluating performance deterioration of a nitrogen oxide storage catalyst which has a nitrogen oxide storage function and an oxygen storage function and is operated with cyclic alternation of the air/fuel ratio in the exhaust gas from lean to rich. The nitrogen oxides are stored during the lean phase and the nitrogen oxides are desorbed and converted during the rich phase.

Abstract: A pressure sensor includes a housing, a support plate arranged on a mounting surface of the housing, a sensor element arranged in the housing, and at least one connector element joined in electrically conductive fashion to at least one contact surface of the support plate. A method for manufacturing a pressure sensor in such a way that the pressure sensor on the one hand can be manufactured easily and on the other hand is resistant to malfunction and is operational over a long period of time. The at least one connector element is arranged flush with the mounting surface and joined directly to the at least one contact surface. A capillary adhesive layer is arranged between the support plate and the mounting surface.

Abstract: A process for producing a ceramic multilayer substrate, particularly an LTCC substrate, in which printed circuit traces and plated contactings are produced in a printing process on a plurality of green ceramic foils using a conductive paste which contains a wax as a printing carrier and is free of highly volatile solvents, and the green ceramic foils subsequently being arranged in a stack one upon the other and fired. The otherwise customary, time-consuming drying of the green ceramic foils for the vaporization of the utilized solvent is eliminated. The foils can be stacked and fired immediately after the printing of the printed circuit traces and plated contactings. Furthermore, shrinkage of the printed circuit traces and the green ceramic foils before the firing is avoided, thereby decisively improving the precision of the produced ceramic multilayer substrates.

Abstract: In a method for producing a pressure sensor, a ceramic plate is joined to a shaped ceramic part. The shaped ceramic part has a depression. Around the depression there is provided a thick-layer paste which does not completely surround the depression. As a result, the air can escape from the depression during firing and a subatmospheric pressure can thus be enclosed in the depression.