Abstract: A method for influencing the exhaust gas temperature of an internal combustion engine is described in which measures can be carried out for increasing, lowering and limiting exhaust gas temperature. Depending on temperature requirements, and in which method these temperature requirements are prioritized, the temperature limitation having the highest priority for ensuring protection of the component parts, the resulting temperature requirement may be achieved by heating measures or cooling measures in such a way that heating measures and cooling measures are not applied at the same time.

Abstract: A method for operating a nitrogen oxide (NOx) storage catalytic converter (12?) of an internal combustion engine (1) includes storing nitrogen oxides (NOx), which are generated by the engine (1), in a first operating phase in the NOx storage catalytic converter (12?). In a second operating phase, nitrogen oxides stored in the NOx storage catalytic converter (12?) are discharged from the NOx storage catalytic converter (12?). The start of the second operating phase is determined based on a nitrogen oxide (NOx) fill level (mnosp) of the NOx storage catalytic converter (12?) and the NOx fill level (mnosp) is modeled based on a nitrogen oxide (NOx) storing model (30). To be able to precisely and reliably determine the start and the end of the second operating phase, a first value of the nitrogen oxide (NOx) mass flow (msnonk_s) rearward of the NOx storage catalytic converter (12?) is detected and the NOx storing model (30) is corrected in dependence upon the detected first value.

Abstract: A method for operating a catalytic converter arranged in the exhaust gas of an internal combustion engine. The composition of exhaust gas being controlled in front of the catalytic converter by adding a reducing agent that promotes the regeneration of the catalytic converter. The composition of the exhaust gas being detected with the aid of an exhaust-gas sensor positioned downstream from the catalytic converter. A time lag between the start of controlling the composition of the exhaust gas in front of the catalytic converter and the detection of a change in the composition after the catalytic converter are evaluated. In order to be able to determine the end of a regeneration phase of the catalytic converter in a safe and reliable manner, the gradient of an output signal of the exhaust-gas sensor is evaluated.

Abstract: A method of desulfurization of a ceramic storage medium for sulfur oxides and/or nitrogen oxides situated in a gas stream, in particular a storage device for nitrogen oxides or sulfur oxides situated in the exhaust gas stream of an internal combustion engine, is described, a mixture having a low oxygen concentration being established in the gas stream to release the stored sulfur oxides. A measuring signal is recorded by an oxygen probe positioned downstream from the storage medium in a gas stream flow direction, the curve of this measuring signal being used to determine the loading of the storage medium with sulfur oxides. This method allows determination of the need for desulfurization as a function of the loading of the storage medium with sulfur oxides, to monitor and control the progress of desulfurization initiated and to check on how complete the desulfurization that is concluded has been.

Abstract: A method for determining the NOx mass flow at the input of an NOx storage catalytic converter in the exhaust gas of an internal combustion engine from operating parameters of the internal combustion engine is introduced, characterized in that the intake air temperature and the engine oil temperature are considered in the determination.

Abstract: A heating of a catalytic converter in the exhaust gas of an internal combustion engine is presented which can be operated in different operating modes and wherein at least one of several heating measures can be selected so that, at first, an estimate can be made for several heating measures as to whether an individual heating measure can make the desired heating effect available and that it is further estimated whether an individual heating method can be carried out in the instantaneous operating state with a view to the exhaust-gas values and the operating mode of the internal combustion engine, which is necessary for carrying out the heating measure; and that that operating mode is requested wherein the requests can best be satisfied and that at least one possible heating measure is activated in dependence upon the instantaneous mode of operation. The invention further is directed to an electronic control unit for carrying out the method.

Abstract: An internal combustion engine, in particular for a motor vehicle, in which fuel may be injected into a combustion chamber during an intake phase in a first mode of operation or during a compression phase in a second mode of operation, and in which exhaust gases may be sent to a catalytic converter. A control unit determines a temperature difference between an actual exhaust gas temperature and a setpoint exhaust gas temperature at an operating point having a low exhaust gas temperature. In addition, at least one additional injection after combustion is implemented by the control unit as a function of the temperature difference.

Abstract: An internal combustion engine in a motor vehicle, for example, is equipped with a combustion chamber, into which fuel may be injected in a rich mode of operation and in a lean mode of operation, and is also equipped with a catalyst, in which nitrogen oxides may be stored. A control unit is provided for switching between rich and lean modes of operation, for determining a quality function for storage of nitrogen oxides in the catalyst, and for switching between these modes of operation as a function of the quality function.

Abstract: The present invention relates to a method for operating a catalytic converter (12) situated in the exhaust gas of an internal combustion engine (1), the composition of exhaust gas being controlled in front of the catalytic converter (12) by adding a reducing agent that promotes the regeneration of the catalytic converter (12), and the composition of the exhaust gas being detected with the aid of an exhaust-gas sensor (14) positioned downstream from the catalytic converter (12), and a time lag between the start of controlling the composition of the exhaust gas in front of the catalytic converter (12) and the detection of a change in the composition after the catalytic converter (12) being evaluated. In order to be able to determine the end of a regeneration phase (23, 33) of the catalytic converter (12) in a safe and reliable manner, it is proposed that the gradient of an output signal (31) of the exhaust-gas sensor (14) be evaluated.

Abstract: A method of desulfurization of a ceramic storage medium (10, 12) for sulfur oxides and/or nitrogen oxides situated in a gas stream, in particular a storage device for nitrogen oxides or sulfur oxides situated in the exhaust gas stream of an internal combustion engine is described, a mixture having a low oxygen concentration being established in the gas stream to release the stored sulfur oxides. A measuring signal is recorded by an oxygen probe (14) situated downstream from the storage medium (10, 12) in the direction of flow of the gas stream, the curve of this measuring signal being used to determine the loading of the storage medium (10, 12) with sulfur oxides. This method makes it possible to determine the need for desulfurization as a function of the loading of the storage medium (10, 12) with sulfur oxides, to monitor and control the progress of desulfurization initiated and to check on how complete the desulfurization that is concluded has been.

Abstract: A method for heating a catalytic converter in internal combustion engines is introduced wherein: an index for the temperature of the catalytic converter is formed; below a predetermined temperature of the catalytic converter, a first heating measure takes place wherein the temperature of the exhaust gas is increased; and, above the predetermined temperature, alternatively or supplementary to the first heating measure, a second heating measure takes place wherein a reaction-capable mixture is supplied to the catalytic converter in addition to the exhaust gas and the reaction of this mixture releases heat in the catalytic converter.

Abstract: An internal combustion engine in particular for a motor vehicle is described, which is provided with a storage catalytic converter, which is filled with and emptied of nitrogen oxides. Using the control unit, a plurality of aging conditions of the storage catalytic converter can be determined. Using the control unit, a reversible aging curve and a non-reversible aging curve can be determined from the aging conditions.

Abstract: An internal combustion engine, especially for a motor vehicle, is described, which is provided with a storage catalytic converter which can be loaded with and unloaded of nitrogen oxides. Several states of deterioration (points 13) of the storage catalytic converter can be determined by the control apparatus. A sulphur content of the fuel used can be determined by the control apparatus from sequential states of deterioration (points 13).

Abstract: A heating of a catalytic converter in the exhaust gas of an internal combustion engine is presented which can be operated in different operating modes and wherein at least one of several heating measures can be selected so that, at first, an estimate can be made for several heating measures as to whether an individual heating measure can make the desired heating effect available and that it is further estimated whether an individual heating method can be carried out in the instantaneous operating state with a view to the exhaust-gas values and the operating mode of the internal combustion engine, which is necessary for carrying out the heating measure; and that that operating mode is requested wherein the requests can best be satisfied and that at least one possible heating measure is activated in dependence upon the instantaneous mode of operation. The invention further is directed to an electronic control unit for carrying out the method.

Abstract: The invention relates to a method and a model for modeling a discharge phase of a nitrogen oxide (NOx)-storage catalytic converter (12′) of an internal combustion engine (1), especially of a motor vehicle. The NOx-storage catalytic converter (12′) is subdivided into an oxygen (O2)-store and a nitrogen oxide (NOx)-store and a reducing agent mass flow (msrg) is determined which charges the O2-store and the NOx-store. In order to model a discharge phase of the NOx-storage catalytic converter (12′) reliably and precisely and with the least possible complexity, the suggestion is made that the O2-store is modeled via a first integrator for oxygen (O2) and the NOx-store via a second integrator for nitrogen oxide (NOx) and the first integrator and the second integrator are charged proportionally with the reducing agent mass flow (msrg) in accordance with an apportioning factor.

Abstract: The invention relates to a method for operating a nitrogen oxide (NOx) storage catalytic converter (12′) of an internal combustion engine (1), especially of a motor vehicle, wherein, during a first operating phase of the storage catalytic converter (12′), nitrogen oxides are stored in the storage catalytic converter (12′) and, during a second operating phase, stored nitrogen oxides are discharged from the storage catalytic converter (12′) and, during the first operating phase, the stored quantity of nitrogen oxides is determined. In order to be able to determine start and end of the second operating phase as accurately as possible, it is suggested that a quantity, which characterizes the discharge quantity of nitrogen oxides, is determined during the second operating phase and is compared to the stored quantity of nitrogen oxides determined during the first operating phase.

Abstract: The invention relates to a method for operating a nitrogen oxide (NOx) storage catalytic converter (12′) of an internal combustion engine (1), especially of a motor vehicle. Nitrogen oxides (NOx), which are generated by the engine (1), are stored in a first operating phase in the NOx storage catalytic converter (12′) and, in a second operating phase, nitrogen oxides stored in the NOx storage catalytic converter (12′) are discharged from the NOx storage catalytic converter (12′). The start of the second operating phase is determined based on a nitrogen oxide (NOx) fill level (mnosp) of the NOx storage catalytic converter (12′) and the NOx fill level (mnosp) is modeled based on a nitrogen oxide (NOx) storing model (30).

Abstract: A method for determining the NOx mass flow at the input of an NOx storage catalytic converter in the exhaust gas of an internal combustion engine from operating parameters of the internal combustion engine is introduced, characterized in that the intake air temperature and the engine oil temperature are considered in the determination.

Abstract: An internal combustion engine (1), in particular for a motor vehicle, is described; it is equipped with a catalytic converter (12) which may be exposed to nitrogen oxides. A lambda probe (13) is provided for measuring the oxygen concentration downstream from the catalytic converter (12). The nitrogen oxides supplied to the catalytic converter (12) are increased by a controller (18), and the conversion capacity of the catalytic converter (12) is concluded from the increase in oxygen concentration downstream from the catalytic converter (12).

Abstract: An internal combustion engine (1), in particular for a motor vehicle, is described, in which fuel may be injected into a combustion chamber (4) during an intake phase in a first mode of operation or during a compression phase in a second mode of operation, and in which exhaust gases may be sent to a catalytic converter (12). A control unit (18) determines a temperature difference between an actual exhaust gas temperature and a setpoint exhaust gas temperature at an operating point having a low exhaust gas temperature. In addition, at least one additional injection after combustion is implemented by the control unit (18) as a function of the temperature difference.