Abstract: To ensure the maximum possible conversion of nitrogen oxides in a DeNOx catalytic converter in an off-gas cleaning installation for reducing nitrogen oxides and, at the same time, to prevent the reducing agent which is used for the reduction from escaping into the environment, there is provision for the density of a reducing agent solution to be used to determine the volume of the reducing agent solution which is to be metered. The density is regulated in two ways, in that the temperature of the reducing agent solution is measured using a temperature sensor and set by a temperature-control device.

Abstract: A static mixer in the exhaust emission control system of an excess-air-operated combustion engine is formed of an expanded grid with a plurality of openings formed between crossbars. Using an expanded grid achieves both good mixing of the exhaust gas with a reducing agent in a short mixing path and properly aligns the exhaust flow.

Abstract: When determining the amount of a reducing agent solution to be introduced into the exhaust gas of a combustion system, in particular of a diesel engine, for catalytically reducing the nitrogen oxides by the SCR process, the concentration of the reducing agent in the reducing agent solution as well as the parameters characterizing the operating state of the combustion system, the exhaust gas and/or the catalyst are taken into consideration. As a result, the safety margin with respect to a theoretically optimum amount to be introduced that is required to avoid a leakage of reducing agent can be reduced, whereby the conversion rate of the nitrogen oxides is improved.

Abstract: A method is provided for the catalytic conversion of nitrogen oxides contained in the exhaust gas of an internal combustion engine. A reducing agent is added in a controlled manner upstream of a denitrification catalyst, as seen in exhaust gas flow direction, and in dependence on a nitrogen oxide concentration. The reducing agent is added in a superstoichiometric amount in relation to the nitrogen oxide content if an operating parameter and/or a value derived from the operating parameter falls below or exceeds a threshold value. The addition of the reducing agent is then terminated or continued in a substoichiometric manner. The invention provides a measure for obtaining an extremely high average nitrogen oxide conversion, especially under varying operating conditions of the internal combustion engine.

Abstract: A static mixer in the exhaust emission control system of an excess-air-operated combustion engine is formed of an expanded grid with a plurality of openings formed between crossbars. Using an expanded grid achieves both good mixing of the exhaust gas with a reducing agent in a short mixing path and properly aligns the exhaust flow.

Abstract: A method and a device for controlling a combustion system, in particular an internal combustion engine, and for catalytic cleaning of exhaust gases, as well as a combustion system, catalytically remove a noxious substance from the exhaust gas with the aid of a fluid which is added in a metered manner to the noxious substance. A desired value for a mass flow of the noxious substance in the exhaust gas is prescribed in order to control the combustion system. In this way, the metered addition of the fluid in accordance with the mass flow of the noxious substance is substantially simplified.

Abstract: A microwave hydrolysis reactor for converting urea into ammonia has one or more reaction chambers into which a urea solution is fed via a feed device and a discharge device for discharging an ammonia-water mixture. A catalytic converter is arranged in the reaction chamber. A microwave-transmitting device allows irradiating so that energy is fed to the urea solution in the reaction chamber.

Abstract: A device for introducing a liquid reducing agent into an exhaust gas purification system includes a gas line for receiving and carrying a gas, a reducing agent line for receiving and carrying a liquid reducing agent, a mixing chamber for mixing the reducing agent with the gas, the mixing chamber fluidically connected to the gas line and to the aid reducing agent line, a metering valve disposed in the reducing agent line; and a control device for controlling a pressure in the reducing agent line dependent upon a gas pressure in the gas line. The control device can also be used for controlling the reducing agent throughput in the reducing agent line in dependence on the gas pressure in the gas line.

Abstract: A tank for a vehicle having a selective catalytic reduction exhaust gas purification system operating with a reducing agent includes a fuel space for the vehicle fuel and a reducing agent space for the reducing agent. The fuel space and the reducing agent space are combined into a single structural that can be fastened as a whole to the vehicle by brackets on the structural unit. This utilizes the limited space available in any vehicle as efficiently as possible and eliminates the need to provide mounting arrangements for separate fuel and reducing agent tanks.

Abstract: Excessive NOx emission in a diesel internal combustion engine with SCR exhaust gas treatment is detected by a control unit. The excessive NOx emission value is determined from the catalytic-converter efficiency calculated for the metering of the reducing agent. In response, measures are taken, such as delayed start of the fuel injection, deactivation of a coasting cutoff, reducing an exhaust gas recirculation rate and/or increasing the idling speed. As a result, the NOx content in the untreated exhaust gas drops, the catalytic-converter temperature increases more quickly after a cold start, and the NOx emission is reduced.

Abstract: A NO.sub.x reduction system includes an SCR catalytic converter and a metering assembly for reducing agent. A control unit for the reduction system is integrated together with the actuators and sensors as a functional unit at the reducing agent container. This provides savings in terms of lines and plug-in connections, and relieves the burden on the control unit of the internal combustion engine.

Abstract: A method and a device for decomposing nitrogen oxides in an exhaust gas of an internal combustion engine, include feeding the exhaust gas and a reactant which is sprayed into the exhaust gas through the use of compressed air, to a catalytic converter. A compressor for supplying compressed air is associated with the internal combustion engine, and part of the compressed air is diverted and used as the compressed air for injecting the reactant. The sprayed reactant is fed to the catalytic converter, together with the exhaust gas to be purified, which ensures the decomposition of the nitrogen oxides, in particular according to the method of selective catalytic reaction.

Abstract: A premixing chamber of a nebulizing device for an exhaust gas purification system serves to mix a compressed gas such as compressed air, for example, with a reducing agent such as urea solution, for example. The premixing chamber is set up on the carburetor principle and includes a compressed gas feed having a taper and a reducing agent feed opening in the region of the taper. The premixing chamber ensures that no deposits originating from the reducing agent can settle in the region of the mixing route. The premixing chamber is provided, in particular, for an exhaust gas purification system of a vehicle fitted with a regulated diesel catalytic converter as well as for stationary diesel engines of up to about 1000 kW (mechanical power).

Abstract: A rail vehicle, has at least two vehicle sections joined pivotably to one another so as to provide an intermediate space dimension to suit relative motions while traveling around curbs as well as over dips and humps, at least one line provided for each of the vehicle sections for electrical current, air or hydraulic fluid, the at least one line having a line segment that compensates a relative motion of the vehicle sections, a sleeve which spans the intermediate space between the vehicle sections, the sleeve enveloping the line and being connected to the line in a shear-resistant manner, the line segment that compensates for the relative motions of the vehicle sections outside the sleeve extending in a horizontal disposition.

Abstract: Nitrogen oxides emitted by an internal-combustion engine operated with excess air are normally converted by the method of selective catalytic reduction by bringing the nitrogen oxides, together with ammonia, into contact with a selective catalyst. Due to the dangers associated with the use of ammonia, in a motor vehicle ammonia should only be carried in the form of a substance which liberates ammonia, generally an aqueous urea solution. A method and a device for introducing liquid into an exhaust-gas purification system according to the invention avoids frost damage to sections of the system during shutdown times and permits operation of the system at temperatures below the freezing point of the reducing agent solution being used. The method and device include a (thermally insulated) reservoir for the reducing agent liquid and a liquid supply line which is connected thereto and terminates in an outlet opening for the liquid. The reservoir and the liquid supply line can be heated.

Abstract: A method is provided in which the reducing agent, during the starting phase of the internal-combustion engine and during operation with decreasing and, if appropriate, virtually constant exhaust gas temperature, is fed superstoichiometrically in relation to the nitrogen oxide concentration, while taking into account the temperature-dependent storage capacity of a denitration catalytic converter for the reducing agent. The reducing agent is otherwise fed substoichiometrically. In this manner, the catalytic converter is kept at all times at a preferred charge level, so that on one hand it is possible to provide sufficient stored reducing agent for the catalytic conversion and on the other hand it is possible to still have a reducing agent buffer available which avoids slip of the reducing agent. The invention can be used in all internal-combustion engines operated with air excess, such as diesel engines and lean-burn engines.

Abstract: A piston for diesel engines is made of a toughness-increasing aluminium alloy containing copper, nickel, silicon, magnesium, iron and manganese. The use of this material, which can conventionally be chill-cast, and by implying special dimensions, provides a piston which, despite its relatively light construction, provides the utmost security against cracking in the stressed regions, e.g. the piston boss or the combustion chamber recess.

Abstract: A brass alloy, a process for the production of a brass material or semi-finished brass product from that type of a brass alloy, as well as to the utilization of the brass material; in essence, the brass alloy for semi-finished products and semi-finished articles, which in addition to a good workability must possess a high resistance to wear, especially when employed for synchronous rings. The foregoing is possible through the intermediary of entirely determined contents of chromium and/or zircon in the previously described brass alloy. The chromium contents hereby vary, on the one hand, in dependence upon the silicon contents, and on the other hand, however, also to a lesser measure upon the remaining alloy components within the range of between 0.01 to 0.15% by weight, and preferably between 0.05 and 0.1% by weight.