Abstract: In an air compressor, particularly for an internal combustion engine, which compressor has a compressor housing with a flow duct structure and a recirculation arrangement including a bypass structure for recirculation some of the air entering the compressor wheel, a recirculating ring is arranged in the bypass flow structure around the compressor wheel which ring has a plurality of flow passages distributed uniformly around its circumference with inflow orifices at the radial inner end in communication with the compressor flow duct and outflow orifice at the radial outer end in communication with a by-pass flow space.

Abstract: In an exhaust gas turbocharger for an internal combustion engine including an exhaust gas turbine and a compressor connected to the turbine so as to be operated thereby, the turbine includes a housing consisting of an inner and an outer shell formed from steel sheets and being arranged in spaced relationship so as to form therebetween an intermediate space.

Abstract: In a process and apparatus for two-stage supercharging of process air for a fuel cell, in one of the two charging stages, supercharging taking place by means of a displacement machine. In the other charging stage, supercharging is performed by means of a combined expansion and compression machine. Energy is recovered from the exhaust gas of a fuel cell by means of the combined expansion and compression machine.

Abstract: In an internal combustion engine including an exhaust gas turbocharger and a compound power turbine connected to the crankshaft of the engine and an exhaust gas recirculation system extending between the engine exhaust duct upstream of the exhaust gas turbine and the intake duct downstream of the compressor of the exhaust gas turbocharger, the exhaust gas turbine and the compound power turbine have a size relationship determined by the power absorption capability &phgr; of each turbine such that: 1 φ = m .

Abstract: An internal combustion engine has an exhaust gas turbocharger with an exhaust gas turbine and a compressor. In addition, an air-driven turbine is provided which is torsionally connected to the compressor and to which combustion air can be supplied via an adjustable shut-off element. For operation of the exhaust gas turbocharger over a wide operating spectrum, an additional duct is provided between compressor inlet and the air inlet of the air turbine, the air supply in the additional duct being adjustable by the shut-off element. In the lower load range, in the case where the required boost pressure falls below a threshold value, the additional duct is opened by means of the shut-off element and the air supply to the compressor inlet is reduced.

Abstract: In an exhaust gas turbocharger for an internal combustion engine, in which a compressor is disposed in the intake duct and a turbine is disposed in the exhaust duct, and wherein the turbine has a turbine wheel in a turbine housing with at least one inlet flow passage for the introduction of exhaust gas which flow passage is provided with a variable turbine geometry for the variable setting of the effective turbine inlet flow passage cross-section, the variable turbine geometry being adjustable between a shut-off position that minimizes the turbine inlet flow cross-section and an open position that maximizes the turbine inlet flow cross-section, a gas-collecting chamber is provided which is in communication with the inlet flow passage in the turbine housing, the total volume of flow passage and the gas-collecting chamber being adjustable by an actuator movably disposed in the turbine housing as a function of the operating state of the internal combustion engine.

Abstract: In an exhaust gas turbocharger for an internal combustion engine having an air intake duct and an exhaust duct and wherein the turbocharger includes a compressor arranged in the air intake duct and a turbine arranged in the exhaust duct and a shaft carrying the turbine wheel and the compressor impeller, an electric motor is provided which includes a rotor provided with an air mover disposed in the inlet area of the compressor and being controllable for rotation independently of the rotation of the turbine.

Abstract: In an exhaust gas turbocharger for an internal combustion engine having an exhaust gas turbine arranged in an exhaust gas line, and a compressor arranged in an intake duct and connected to the turbine by way of a shaft, the compressor includes a compressor wheel forming at the same time a rotor of an electric motor.

Abstract: In a process and apparatus for two-stage supercharging of process air for a fuel cell, in one of the two charging stages, supercharging taking place by means of a displacement machine. In the other charging stage, supercharging is performed by means of a combined expansion and compression machine. Energy is recovered from the exhaust gas of a fuel cell by means of the combined expansion and compression machine.

Abstract: An exhaust-gas turbocharger for an internal combustion engine has an exhaust-gas turbine in the exhaust tract and a compressor in the intake tract, the exhaust-gas turbine and the compressor being connected via a shaft which is supported in a casing of the exhaust-gas turbocharger via at least one bearing. In order to improve the efficiency of the turbocharger, the bearing has a non-contact design, in that, when the exhaust-gas turbocharger is in operation, the shaft is held at a distance from, and so as to be virtually free of friction with, a bearing receptacle fixed to the casing.

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: A process for reducing nitrogen oxides in the exhaust gas of a combustion device, particularly of an internal-combustion engine, includes melting solid pure urea to obtain a molten product, and adding the molten product to the exhaust gas as the reducing agent for reducing nitrogen oxides. The corresponding device includes a device for the controlled liquefaction of solid pure urea and the injection of the molten product into the exhaust gas.

Abstract: A method for operating a multicylinder internal combustion engine with at least one adsorber catalytic converter in the exhaust line of the internal combustion engine includes operating the adsorber catalytic converter with periodically alternating adsorption and desorption operation. The exhaust leaving the adsorber catalytic converter in desorption operation is recycled and/or an oxidation catalytic converter is provided upstream of the adsorber catalytic converter. Exhaust recycling takes place occurs selectively in only one set of the cylinders of the internal combustion engine and this set of cylinders is operated in a state of incomplete combustion during desorption operation. Rich afterburning may be performed during desorption operation of the adsorber catalytic converter in the oxidation catalytic converter connected upstream and the oxidation catalytic converter is operated at an increased temperature during short regeneration phases to remove soot.

Abstract: In a valve for the dosed discharge of fluids particularly a fuel injection valve for fuel injection systems of internal combustion engines, the valve includes in an valve housing at the front end of an injector housing a valve structure at a fluid discharge end of the valve housing and a stack of piezo elements disposed in the opposite end of the injector housing and a high pressure fluid passages leads to the fluid discharge end which is isolated from the area in which the stack of piezo elements is disposed and which is in communication with a low pressure drain passage such that the piezo elements are not exposed to the high pressure fluid. Isolation is obtained by a compensation cylinder movably disposed in an annular space between, and in sealing relationship with, the valve housing, the piezo stack being enclosed in a piezo guide tube which is sealingly connected to the valve housing.

Abstract: A process and apparatus for reducing the nitrogen oxide content in oxygen-containing emissions is provided, particularly for internal-combustion engines, particularly of diesel engines and directly injecting Otto engines for motor vehicles. The nitrogen oxides contained in the exhaust gas are reduced by a suitable reducing agent, such as hydrogen or hydrocarbons, on a DENOX catalyst. For achieving an improved conversion rate for the nitrogen oxides, a combination of hydrogen and hydrocarbons are used as reducing agents. In different operating ranges of the internal-combustion engine only hydrogen, only hydrocarbons, or hydrogen and hydrocarbons are added. Preferably, for this purpose, the quantity of supplied hydrogen or hydrocarbons is reduced or increased with an increasing engine load and/or catalyst temperature and/or rotational engine speed.

Abstract: A motor vehicle exhaust emission control system has two adsorber parts connected in parallel for alternate adsorption and desorption of nitrogen oxides contained in the exhaust from an internal combustion engine and components for conducting further downstream the exhaust that emerges in the adsorber part that is operating at any given time in the adsorption mode and for returning the exhaust that emerges from the other adsorber part that is then operating in the desorption mode, to an intake line of the engine. An oxidizing converter is located upstream of the adsorber part and near the engine for oxidation of the NO contained in the exhaust to form NO.sub.2, so as to permit an increase in the NO.sub.X adsorption rate for the nitrogen adsorber parts.

Abstract: A method and apparatus for injecting a nitrogen-oxide-reducing agent into an exhaust stream that has an injector unit for controlled injection of a reducing agent into the exhaust stream and an injection element that incorporates a micromechanical spray jet element.

Abstract: In a fuel injection system for injecting fuel into a combustion chamber of an internal combustion engine by means of a dual fluid injector which includes a nozzle with a nozzle needle normally closing the nozzle and which has formed around the nozzle needle an annular space which is in communication with a fluid source and a pressure chamber in communication with the annular space and the working space of a plunger disposed in the injector so as to be movable between upper and lower end positions but being biased to its upper end position, the plunger working space is in communication with a fuel source via a fuel supply line which includes a control valve and an electromagnetically controlled valve is provided for controlling the admission of a hydraulic operating fluid to the plunger for moving the plunger into the working space for the ejection of the fuel and the fluid from the pressure chamber and the annular space around the nozzle and the fuel supply line includes an electronically controllable valve a

Abstract: A process and apparatus for the selective catalyzed NO.sub.x reduction in oxygen-containing exhaust gases of internal-combustion engines. For improving the reduction of nitric oxides, hydrocarbons and air are supplied to the exhaust gas purifier and, for producing reactive short-chained unsaturated hydrocarbons, a defined quantity of fuel from the stored fuel intended for the fuel supply of the internal-combustion engine is catalytically cracked and is oxidized by the simultaneous supply of air. The resulting species are guided into the exhaust gas flow of the exhaust gases which are to be purified.

Abstract: In a fuel injection system for an internal-combustion engine which includes a dual-fluid nozzle which is supplied with fuel by a high-pressure pump and with water by a feed pump providing a substantially lower pressure than the high-pressure pump and which has disposed in a nozzle body a nozzle needle which is spring biased into a closing position where one end of the needle is seated on a valve seat, a fuel supply passage extends to an annular space around the valve needle and a branch passage leads to a control chamber formed at the other end of the valve needle and includes a solenoid valve for controlling the application of pressurized fluid to, and the release thereof from, the other end of the nozzle needle, an additional fluid line extends from the feed pump to the annular space and includes a check valve for permitting flow of additional fluid only toward the annular space and a pressure relief line in communication with the fuel supply passage via a control valve, and a control device is provided for