Abstract: A method for operating an exhaust-gas purification system which is arranged in the exhaust system of an internal combustion engine, and an exhaust-gas purification system, are described. In the method, a combination of electrical catalytic converter heating measures with internal combustion engine catalytic converter heating measures is implemented, whereby particularly fast and inexpensive heating of a catalytic converter is achieved. The corresponding exhaust system preferably has, in an exhaust-gas flow direction, firstly a support catalytic converter and then a heated catalytic converter.

Abstract: A method for operating an exhaust-gas purification system which is arranged in the exhaust system of an internal combustion engine, and an exhaust-gas purification system, are described. In the method, a combination of electrical catalytic converter heating measures with internal combustion engine catalytic converter heating measures is implemented, whereby particularly fast and inexpensive heating of a catalytic converter is achieved. The corresponding exhaust system preferably has, in an exhaust-gas flow direction, firstly a support catalytic converter and then a heated catalytic converter.

Abstract: The present disclosure describes a method for checking the signal of a temperature sensor in an exhaust-gas aftertreatment system for an internal combustion engine. The method may include: in an operating state which does not require heating of the reducing agent, activating the heating device for the purposes of checking the temperature sensor; determining whether the signal of the temperature sensor changes by a predefined expected value (?T) within a predefined time period (?t2); provisionally identifying the temperature sensor as fault-free if it does; deactivating the heating device; determining whether the signal of the temperature sensor reaches the start temperature (T0) again within a time period (?t3); and confirming the temperature sensor as fault-free if it does.

Abstract: The present disclosure relates to engines for a motor vehicle and some embodiments include a method for operating an exhaust train of a motor vehicle engine including: measuring a particle concentration downstream of a particle filter at a first operating point; determining the filter efficiency at the first operating point; changing operation of the engine to a second operating point to increase the particle emissions; measuring the particle concentration downstream of the filter at the second operating point; determining the filter efficiency at the second operating point; determining a difference between the efficiency levels; detecting an offset error, if the difference exceeds a defined threshold; and identifying a particle sensor as defective if an offset error is detected, rather than identifying the particle filter as defective.

Abstract: The present disclosure relates to engines for a motor vehicle and some embodiments include a method for operating an exhaust train of a motor vehicle engine including: measuring a particle concentration downstream of a particle filter at a first operating point; determining the filter efficiency at the first operating point; changing operation of the engine to a second operating point to increase the particle emissions; measuring the particle concentration downstream of the filter at the second operating point; determining the filter efficiency at the second operating point; determining a difference between the efficiency levels; detecting an offset error, if the difference exceeds a defined threshold; and identifying a particle sensor as defective if an offset error is detected, rather than identifying the particle filter as defective.

Abstract: The present disclosure describes a method for checking the signal of a temperature sensor in an exhaust-gas aftertreatment system for an internal combustion engine. The method may include: in an operating state which does not require heating of the reducing agent, activating the heating device for the purposes of checking the temperature sensor; determining whether the signal of the temperature sensor changes by a predefined expected value (?T) within a predefined time period (?t2); provisionally identifying the temperature sensor as fault-free if it does; deactivating the heating device; determining whether the signal of the temperature sensor reaches the start temperature (T0) again within a time period (?t3); and confirming the temperature sensor as fault-free if it does.

Abstract: To operate an internal combustion engine, a specified forced stimulation is applied to an air ratio as the basis for a target value of a lambda controller. In diagnostic operation, a diagnostic function is used to identify a probe error of the exhaust gas probe, and a value of the measurement signal is recorded as a start value in chronological correlation with an edge of the target value curve of the lambda controller and the current value of the measurement signal is recorded as an end value after a specified first time duration. The start and end values are used to determine whether a filter error or a dead time error of the exhaust gas probe exists. The first time duration is specified such that start value/end value difference for a filter error differs start value/end value difference for a dead time error by at least a specified difference value.

Abstract: To operate an internal combustion engine, a specified forced stimulation is applied to an air ratio as the basis for a target value of a lambda controller. In diagnostic operation, a diagnostic function is used to identify a probe error of the exhaust gas probe, and a value of the measurement signal is recorded as a start value in chronological correlation with an edge of the target value curve of the lambda controller and the current value of the measurement signal is recorded as an end value after a specified first time duration. The start and end values are used to determine whether a filter error or a dead time error of the exhaust gas probe exists. The first time duration is specified such that start value/end value difference for a filter error differs start value/end value difference for a dead time error by at least a specified difference value.

Abstract: An exhaust gas catalytic converter is laden with oxygen until it is saturated at least upstream of an exhaust gas probe. A predefined first rich air/fuel ration is set in a combustion chamber of a cylinder. A first oxygen storage capacity value is determined as a function of the measurement signal of an exhaust gas probe and the predefined first rich air/fuel ratio. The exhaust gas catalytic converter is laden with oxygen until it is saturated. A predefined second rich air/fuel ration is set in the combustion chamber of the cylinder. A second oxygen storage capacity value is determined as a function of the measurement signal of the exhaust gas probe and the predefined second rich air/fuel ration. A corrected oxygen storage capacity value is determined as a function of the first and second oxygen storage capacity values.

Abstract: A method for controlling an SCR-exhaust gas after-treatment system (1) of an internal combustion engine (8), in particular of an internal combustion engine of a motor vehicle, has one or more steps for determining the quality of the reducing means.

Abstract: An exhaust catalyst is charged with oxygen until saturated. A given first rich air/fuel ratio (LAM1_SP) is set in a combustion chamber of a cylinder. A first oxygen storage capacity value (OSC1) is determined depending on the measured signals (MS1, MS2) from first and second exhaust probes. The exhaust catalyst is charged with oxygen until saturated. A given second rich air/fuel ratio is set in the combustion chamber of the cylinder. A second oxygen storage capacity value (OSC2) is determined depending on the measured signal from the first and second exhaust probe. A corrected oxygen storage capacity value (OSC_COR) is determined depending on the first and second oxygen storage capacity values (OSC1, OSC2).

Abstract: In a method and a device for the diagnosis of an NOx sensor (54) for an internal combustion engine, during a homogenous operation of the internal combustion engine, a base diagnostic value (NOx_DIAG_BAS) of the NOx sensor (54) is determined as a function of a reference value (I_REF) of a measuring signal of the NOx sensor (54) determined in a new state of the NOx sensor (54) and a current value (I_AV) of the measuring signal of the NOx sensor (54). A time-dependent measuring value sequence (O2_EG_T) of the oxygen content of the exhaust gas in the exhaust gas system (14) is determined by the exhaust gas probe (53). Depending on the measuring value sequence (O2_EG_T) of the oxygen content of the exhaust gas, and the base diagnostic value (NOx_DIAG_BAS) of the NOx sensor (54), a corrected diagnostic value (NOx_DIAG_COR) is determined for the NOx sensor (54).

Abstract: A regeneration method for a storage catalytic converter in an exhaust-gas purification system of an internal combustion engine, has the following steps: (a) switching of the internal combustion engine from a standard operating mode with a lean exhaust gas to a regeneration mode with a rich exhaust gas, (b) measurement of a nitrogen oxide concentration in the exhaust gas of the internal combustion engine after the switchover to the regeneration mode, (c) determination of a characteristic variable of a desorption peak of the measured nitrogen oxide concentration after the switchover to the regeneration mode, and (d) minimization of the characteristic variable of the desorption peak through controlling of the internal combustion engine as a function of the measured characteristic variable of the desorption peak.

Abstract: An internal combustion engine has a NOX storage catalyst. A storage capacity (NOX_STC) of the NOX storage catalyst is determined for the purpose of operating the internal combustion engine. The temperature (TEMP) of the NOX storage catalyst is increased if the storage capacity (NOX_STC) is less than a predefined threshold value.

Abstract: According to a current operating state (BZ) of an internal combustion engine and/or a specified particle number emission limit (PE), a minimum hydrocarbon concentration (HCMK) of a combustion chamber exhaust gas of the internal combustion engine that is required to comply with the specified particle number emission limit is determined. An operation (B) of the internal combustion engine is specified to achieve a hydrocarbon concentration (HCK) of the combustion chamber exhaust gas that is at least as large as the determined minimum hydrocarbon concentration (HCMK).

Abstract: An exhaust gas catalytic converter is laden with oxygen until it is saturated at least upstream of an exhaust gas probe. A predefined first rich air/fuel ration is set in a combustion chamber of a cylinder. A first oxygen storage capacity value is determined as a function of the measurement signal of an exhaust gas probe and the predefined first rich air/fuel ratio. The exhaust gas catalytic converter is laden with oxygen until it is saturated. A predefined second rich air/fuel ration is set in the combustion chamber of the cylinder. A second oxygen storage capacity value is determined as a function of the measurement signal of the exhaust gas probe and the predefined second rich air/fuel ration. A corrected oxygen storage capacity value is determined as a function of the first and second oxygen storage capacity values.

Abstract: An exhaust as catalytic converter is laden with oxygen until it is saturated at least upstream of an exhaust as probe. A predefined first rich air/fuel ration is set in a combustion chamber of a cylinder. A first oxygen storage capacity value is determined as a function of the measurement signal of an exhaust as probe and the predefined first rich air/fuel ratio. The exhaust as catalytic converter is laden with oxygen until it is saturated. A predefined second rich air/fuel ration is set in the combustion chamber of the cylinder. A second oxygen storage capacity value is determined as a function of the measurement signal of the exhaust as probe and the predefined second rich air/fuel ration. A corrected oxygen storage capacity value is determined as a function of the first and second oxygen storage capacity values.

Abstract: An exhaust catalyst is charged with oxygen until saturated. A given first rich air/fuel ratio (LAM1_SP) is set in a combustion chamber of a cylinder. A first oxygen storage capacity value (OSC1) is determined depending on the measured signals (MS1, MS2) from first and second exhaust probes. The exhaust catalyst is charged with oxygen until saturated. A given second rich air/fuel ratio is set in the combustion chamber of the cylinder. A second oxygen storage capacity value (OSC2) is determined depending on the measured signal from the first and second exhaust probe. A corrected oxygen storage capacity value (OSC_COR) is determined depending on the first and second oxygen storage capacity values (OSC1, OSC2).

Abstract: IN a method and a device for the diagnosis of an NOx sensor (54) for an internal combustion engine, during a homogenous operation of the internal combustion engine, a base diagnostic value (NOx_DIAG_BAS) of the NOx sensor (54) is determined as a function of a reference value (I_REF) of a measuring signal of the NOx sensor (54) determined in a new state of the NOx sensor (54) and a current value (I_AV) of the measuring signal of the NOx sensor (54). A time-dependent measuring value sequence (O2_EG_T) of the oxygen content of the exhaust gas in the exhaust gas system (14) is determined by the exhaust gas probe (53). Depending on the measuring value sequence (O2_EG_T) of the oxygen content of the exhaust gas, and the base diagnostic value (NOx_DIAG_BAS) of the NOx sensor (54), a corrected diagnostic value (NOx_DIAG_COR) is determined for the NOx sensor (54).

Abstract: An exhaust catalyst is charged with oxygen until saturated. A given first rich air/fuel ratio is set in a combustion chamber of a cylinder. A first oxygen storage capacity value is determined depending on the measured signals from first and second exhaust probes. The exhaust catalyst is charged with oxygen until saturated. A given second rich air/fuel ratio is set in the combustion chamber of the cylinder. A second oxygen storage capacity value is determined depending on the measured signal from the first and second exhaust probe. A corrected oxygen storage capacity value is determined depending on the first and second oxygen storage capacity values.