Abstract: A process and a system are used for controlling the mixture composition for an Otto engine with an NOx storage catalyst during a regeneration phase. The process includes controlling, to the value of one, a &lgr;-value (&lgr;M) of an exhaust gas fed to the NOx storage catalyst during a regeneration phase as a function of a &lgr;-value (&lgr;K) of an exhaust gas emitted by the NOx storage catalyst. The system includes a control device for controlling, to the value of one, a &lgr;-value (&lgr;M) of the exhaust gas fed to the NOx storage catalyst during the regeneration phase as a function of the &lgr;-value (&lgr;K) of the exhaust gas emitted by the NOx storage catalyst.

Abstract: A method and an arrangement are provided for reducing warm-up emissions in the exhaust system of a direct-injection internal-combustion engine. The method includes the steps of adjusting a lean air/fuel mixture for the engine-related combustion; implementing a late injection into the exhaust gas during the exhaust cycle of the internal-combustion engine, so that the exhaust gas contains an essentially stoichiometric air/fuel mixture; and igniting the stoichiometric air/fuel mixture contained in the exhaust gas in the proximity of a catalyst device for heating up the catalyst device.

Abstract: An arrangement for igniting a combustible gas mixture for the exhaust system of an internal-combustion engine has a frame device which is wound with a heating wire and can be installed into an exhaust gas train of the exhaust system transversely to the flow axis of the exhaust gas. A power supply device is provided for supplying the heating wire with electric current for generating a predetermined heating wire temperature. The frame device defines a flow range in which a heating wire grid is provided.

Abstract: A method for operating an NOx trap for an internal combustion engine includes measuring parameters that influence the delay between the metering of a regenerating agent and its becoming effective in regenerating the NOx trap. Such parameters include the fuel film on an intake wall and the quantity of oxygen bonded in the catalytic converters upstream of the NOx trap. Measuring these parameters helps determine the quantity of regenerating agent or the number of working cycles required for regeneration of the NOx trap.

Abstract: The invention provides the replacing of the known "macroscopic" processes by a "microscopic" approach control strategy for an NOx accumulator. The regeneration phases after approximately 30 seconds of a lean operation, which last approximately one second in the state of the art, is replaced by a rich operating cycle after a sequence of lean ones. The number of lean operating cycles which can be carried out before a regenerating operating cycle depends on the combustion process of the internal-combustion engine as well as on the construction and the volume of the catalyst.

Abstract: Method for the preparation of high purity substituted benz?e!indoles corresponding to the general formula ##STR1## comprising the preparation of an arylhydrazine which is subjected to a Fischer indole synthesis with a suitable ketone, the benz?e!indole thus obtained being reacted with a radical R.sub.6, followed by subjection to a purification step.This method may more particularly be applied to the synthesis of Indocyanine Green.