Abstract: A method for diagnosing a metering valve for metering a reagent into the exhaust gas region of an internal combustion engine. The metering valve is actuated by a pulse-width-modulated metering valve actuation signal with a certain duty factor for setting the metering rate. A reagent pump places the reagent at a reagent pressure, and the reagent pump is operated with a pulse-width-modulated pump actuation signal with a certain duty factor. Diagnosis of the metering valve is carried out on the basis of an evaluation of the increase in the metering valve actuation signal pulse duty factor after a predefined increase in the metering rate. The reagent filling level of an SCR catalytic converter arranged in the exhaust gas region is taken into account. At the start of the diagnosis, the reagent storage capacity of the SCR catalytic converter is checked.

Abstract: A method for operating an internal combustion engine in whose exhaust-gas region at least one SCR catalytic converter is disposed, which is acted upon by a reagent contributing to the NOx conversion in the SCR catalytic converter, and a device for implementing the method. The reagent level in the SCR catalytic converter is controlled or regulated to a predefined reagent setpoint level, which is specified to at least a maximum value, which corresponds to an SCR catalytic converter completely filled with reagent. In this way the SCR catalytic converter is always operated at the highest possible efficiency at which the highest possible NOx conversion takes place.

Abstract: A method for diagnosing a metering valve for metering a reagent into the exhaust gas region of an internal combustion engine. The metering valve is actuated by a pulse-width-modulated metering valve actuation signal with a certain duty factor for setting the metering rate. A reagent pump places the reagent at a reagent pressure, and the reagent pump is operated with a pulse-width-modulated pump actuation signal with a certain duty factor. Diagnosis of the metering valve is carried out on the basis of an evaluation of the increase in the metering valve actuation signal pulse duty factor after a predefined increase in the metering rate. The reagent filling level of an SCR catalytic converter arranged in the exhaust gas region is taken into account. At the start of the diagnosis, the reagent storage capacity of the SCR catalytic converter is checked.

Abstract: A combustion engine has in the exhaust gas area a SCR-catalyzer with a NH3-filling level, a metering device for supplying the SCR-catalyzer with reactant for reducing nitrous gases, and a downstream NH3-sensitive NOx-sensor. One theoretical value for the NOx downstream of the SCR-catalyzer is compared to an actual NOx-value downstream of the SCR-catalyzer. A reasonability check includes determining a first value for one comparison parameter, which represents the state before a system intervention for adapting the NH3-filling level. A system intervention for adapting the NH3-filling level is carried out and a second value of the comparison parameter is detected. From the comparison of the first value and the second value the reasonability, the non-reasonability, or non-preciseness of the system intervention is assumed.

Abstract: Methods and devices to monitor an exhaust gas after-treatment system of an internal combustion engine with a motor block and an exhaust gas duct. The engine has at least one catalytic converter, upstream from which a reagent substance necessary for the NOx reduction in the catalytic converter is introduced by means of an introduction device. The reduction agent rate is increased to such an extent at defined reference operating points until an ammonia breach is detected in direction of flow behind the catalytic converter by means of an ammonia sensitive sensor in the exhaust gas duct.

Abstract: A method for operating an internal combustion engine in whose exhaust gas region at least one SCR catalytic converter is arranged, a reagent which contributes to NOx conversion in the SCR catalytic converter being applied to said SCR catalytic converter, and a device for carrying out the method are proposed. A measure for the NOx current which occurs downstream of the SCR catalytic converter is both calculated and measured with an NOx sensor which has lateral sensitivity to the reagent. The difference between the calculated measure and the measured measure of the NOx current is determined. A reagent signal which defines the metering of the reagent is influenced as a function of the difference. Plausibility checking is provided, during which the reagent quantity which is metered in a predefined time period and the reagent quantity which is converted in the SCR catalytic converter and/or the converted NOx quantity are compared with one another.

Abstract: invention relates to a method for operating an internal combustion engine, in the exhaust gas section of which is arranged at least one SCR catalytic converter, which is hit with a reagent that contributes to NOx conversion in the SCR catalytic converter, and to a device for implementing the method. At least one measure is calculated for the NOx concentration downstream after the SCR catalytic converter. An NOx sensor, which is arranged downstream after the SCR catalytic converter, generates an exhaust gas sensor signal which corresponds to at least the NOx concentration and optionally, as a result of cross sensitivity, to a reagent slip. A reagent signal, which determines the dosage of reagent, is influenced by a correction signal as a function of the difference and as a function of a measure for the temperature of the SCR catalytic converter.

Abstract: A method and an apparatus for posttreatment of the exhaust gases of an internal combustion engines in which nitric oxides contained in the exhaust gas can be selectively catalytically reduced, and a first auxiliary agent kept on hand can be delivered to the exhaust gas, and means are provided for at least intermittently subjecting a portion of the first auxiliary agent to a chemical conversion into a second auxiliary agent, and an intermediate reservoir is provided for storing the second auxiliary agent, so that at least intermittently, the second auxiliary agent can be delivered to the exhaust gas parallel to or in alternation with the first auxiliary agent.

Abstract: A combustion engine has in the exhaust gas area a SCR-catalyzer with a NH3-filling level, a metering device for supplying the SCR-catalyzer with reactant for reducing nitrous gases and at a downstream NH3-sensitive NOx-sensor. One theoretical value for the NOx downstream of the SCR-catalyzer is compared to an actual NOx-value downstream of the SCR-catalyzer. A reasonability check includes determining a first value for one comparison parameter, which represents the state before a system interference for adapting the NH3-filling level. A system interference for adapting the NH3-filling level is carried out and again a second value of the comparison parameter detected. From the comparison of the first value and the second value the reasonability, the non-reasonability or non-preciseness of the system interference is assumed.

Abstract: A method for operating an internal combustion engine whose exhaust area has at least one SCR catalytic converter and a device for carrying out the method are described. The SCR catalytic converter receiving the reagent supports the conversion of the raw NOx emission of the internal combustion engine. At least a measure of the NOx concentration occurring downstream from the SCR catalytic converter is calculated and this value may be used to define a metering signal for the reagent and/or a heating measure for heating the SCR catalytic converter may be initiated. According to a refinement of this arrangement, a difference between the calculated NOx concentration and the sum of the measured NOx concentration and the measured reagent concentration downstream from the SCR catalytic converter is determined, and it is possible to intervene in the determination of the metering signal depending on the difference.

Abstract: The invention relates to a method for operating an internal combustion engine, in the exhaust gas section of which is arranged at least one SCR catalytic converter, which is hit with a reagent that contributes to NOx conversion in the SCR catalytic converter, and to a device for implementing the method. At least one measure is calculated for the NOx concentration downstream after the SCR catalytic converter. An NOx sensor, which is arranged downstream after the SCR catalytic converter, generates an exhaust gas sensor signal which corresponds to at least the NOx concentration and optionally, as a result of cross sensitivity, to a reagent slip. A reagent signal, which determines the dosage of reagent, is influenced by a correction signal as a function of the difference and as a function of a measure for the temperature of the SCR catalytic converter.

Abstract: A method for operating an internal combustion engine in whose exhaust gas region at least one SCR catalytic converter is arranged, a reagent which contributes to NOx conversion in the SCR catalytic converter being applied to said SCR catalytic converter, and a device for carrying out the method are proposed. A measure for the NOx current which occurs downstream of the SCR catalytic converter is both calculated and measured with an NOx sensor which has lateral sensitivity to the reagent. The difference between the calculated measure and the measured measure of the NOx current is determined. A reagent signal which defines the metering of the reagent is influenced as a function of the difference. Plausibility checking is provided, during which the reagent quantity which is metered in a predefined time period and the reagent quantity which is converted in the SCR catalytic converter and/or the converted NOx quantity are compared with one another.

Abstract: A method for operating a catalytic converter used for purifying the exhaust gas of an internal combustion engine, and a device for implementing the method, which provide for an open-loop or closed-loop control of the reagent fill level in the catalytic converter to a predefined storage setpoint value. The targeted stipulation of the storage setpoint value ensures, on one hand, that in non-stationary states of the internal combustion engine, there is a sufficient quantity of reagent available for the completest possible removal of at least one unwanted exhaust-gas component, and on the other hand, a reagent slip is avoided.

Abstract: A method for operating an internal combustion engine; in the exhaust area of this engine there is at least one catalytic converter and downstream from the catalytic converter there is an NOx sensor. A device for carrying out this method is also provided. The NOx sensor has a cross-sensitivity to a reagent needed in the catalytic converter. In predefined operating states of the internal combustion engine, e.g., idling and/or overrun, a selection signal is supplied; when this selection signal occurs, the sensor signal supplied by the NOx sensor is interpreted as at least a measure of the reagent leakage.

Abstract: The invention relates to the use of DNA-loaded nanoparticles for a transfection of DNA into cells in vitro or in vivo.

Abstract: The invention concerns a procedure to monitor an exhaust gas after-treatment system of an internal combustion engine with a motor block and an exhaust gas duct, which has at least one catalytic converter, upstream from which a reagent substance necessary for the NOx reduction in the catalytic converter is introduced by means of an introduction device, whereby the reduction agent rate is increased to such an extent at defined reference operating points until an ammonia breach is detected in direction of flow behind the catalytic converter by means of an ammonia sensitive sensor in the exhaust gas duct.

Abstract: An exhaust-gas cleaning system for cleaning the exhaust gas of an internal combustion engine with self ignition and/or with direct fuel injection has at least one oxidizing catalytic converter, disposed in an exhaust conduit of the engine, and has at least one device, disposed downstream of the oxidizing catalytic converter for the selective catalytic reduction of the exhaust gases. A delivery device integrated with the at least one oxidizing catalytic converter delivers a reducing agent into the exhaust-gas stream of the engine. A corresponding method for cleaning the exhaust gases of an internal combustion engine is also disclosed.

Abstract: A method for operating an internal combustion engine in whose exhaust-gas region at least one SCR catalytic converter is disposed, which is acted upon by a reagent contributing to the NOx conversion in the SCR catalytic converter, and a device for implementing the method. The reagent level in the SCR catalytic converter is controlled or regulated to a predefined reagent setpoint level, which is specified to at least a maximum value, which corresponds to an SCR catalytic converter completely filled with reagent. In this way the SCR catalytic converter is always operated at the highest possible efficiency at which the highest possible NOx conversion takes place.

Abstract: An exhaust gas purification system for purifying the exhaust gas of an internal combustion engine, especially an internal combustion engine featuring auto-ignition and/or direct fuel injection, is provided. The system includes at least one oxidation catalytic converter disposed in an exhaust gas duct of the internal combustion engine, at least one device for selective catalytic reduction of the exhaust gases which is installed downstream of the oxidation catalytic converter, and a feed device for feeding reducing agent into the exhaust gas stream upstream of, or in, the device for selective catalytic reduction. A switch-over device is provided for selectively feeding reducing agent into the exhaust gas stream upstream of, or inside, the at least one oxidation catalytic converter. A corresponding method for purifying the exhaust gas of an internal combustion engine is also provided.

Abstract: A method and an apparatus for posttreatment of the exhaust gases of an internal combustion engines in which nitric oxides contained in the exhaust gas can be selectively catalytically reduced, and a first auxiliary agent kept on hand can be delivered to the exhaust gas, and means are provided for at least intermittently subjecting a portion of the first auxiliary agent to a chemical conversion into a second auxiliary agent, and an intermediate reservoir is provided for storing the second auxiliary agent, so that at least intermittently, the second auxiliary agent can be delivered to the exhaust gas parallel to or in alternation with the first auxiliary agent.