To keep medium purification efficiency at a high level and prevent deterioration of emission performance. An aspect of the present invention includes: a downstream equivalence ratio calculation unit that calculates a catalyst downstream exhaust gas equivalence ratio by using a catalyst statistical model that receives at least a detection value of an air-fuel ratio sensor on an upstream side of a catalyst and outputs a catalyst downstream exhaust gas equivalence ratio; an oxygen output calculation unit that calculates an output value of an oxygen sensor by using an oxygen sensor statistical model that receives the catalyst downstream exhaust gas equivalence ratio and outputs an output value of the oxygen sensor on the downstream side of the catalyst; a downstream equivalence ratio correction unit that corrects the catalyst downstream exhaust gas equivalence ratio calculated by the downstream equivalence ratio calculation unit based on a calculation result of the oxygen output calculation unit and the detection value of the oxygen sensor; and an air-fuel ratio control unit that controls an air-fuel ratio of an air-fuel mixture of an internal combustion engine based on the corrected catalyst downstream exhaust gas equivalence ratio and air-fuel ratio target value.

A method and a control unit for checking an exhaust gas system in a vehicle. A control unit in the vehicle receives data from sensors of the vehicle and sends out control commands to final control elements of the vehicle. The control unit is in communication connection with an external computer located outside of the vehicle. The external computer causes the control unit to make an active intervention in the exhaust gas system by actuating final control elements of the vehicle. The control unit receives sensor data from the exhaust gas system, which it forwards to the external computer. Based on the sensor data from the sensors, the external computer rates the exhaust gas system as “OK” or “manipulated”.

The present disclosure describes methods for evaluating quality of DEF dosed to an EAS including a close coupled SCR unit a downstream SCR unit. A NOx conversion efficiency of the close coupled SCR unit and a NOx conversion efficiency of the downstream SCR unit are used to evaluate quality of DEF. In some embodiments, the NOx conversion efficiency of close coupled SCR unit is used to evaluate quality of DEF. Operation of an EAS using the results of the evaluation of quality of DEF are described.

A system includes a controller configured to perform an enable operation responsive to receiving information indicative of an enable parameter, the enable operation includes: determining a predicted downstream NOx value of an exhaust gas stream exiting a NOx storage catalyst; determining a downstream NOx value of the exhaust gas stream exiting the NOx storage catalyst; determining an error between the predicted downstream NOx value and the determined downstream NOx value; comparing the error to an error threshold; and determining that the NOx storage catalyst is in good health responsive to determining that the error does not exceed the error threshold. The controller is further configured to perform a disable operation responsive to receiving information indicative of a disable parameter, the disable operation causing a deactivation of at least a portion of the controller.

A method is provided for ascertaining a NO.sub.x concentration and an NH.sub.3 slip downstream from an SCR catalytic converter of an internal combustion engine of a vehicle. State variables of an internal combustion engine as first input variables and an updated NH.sub.3 fill level of the SCR catalytic converter as a second input variable cooperate with at least one machine learning algorithm or at least one stochastic model. The at least one machine learning algorithm or at least one stochastic model calculates the NO.sub.x concentration and the NH.sub.3 slip downstream from the SCR catalytic converter as a function of the first input variables and the second input variables and output the same as output variables.

A catalyst deterioration diagnosis apparatus includes an upstream side air-fuel ratio detector, a downstream side air-fuel ratio detector, an air-fuel ratio variation integrator that integrates the output variations of the respective air-fuel ratio detectors when a diagnosis running condition is satisfied, and a determiner that determines catalyst deterioration when the output variation integrated value of the upstream side air-fuel ratio detector exceeds a predetermined integration ending threshold, and further when a ratio between the output variation integrated value of the two detectors exceeds a predetermined determination threshold. The air-fuel ratio variation integrator holds the integrated values when the diagnosis running condition becomes unsatisfied before the integrated value of the upstream side air-fuel ratio detector reaches the integration ending threshold. The air-fuel ratio variation integrator resumes the integration using the held values as initial values when the diagnosis running condition is satisfied later again.

A method for operating an internal combustion engine having a motor and an exhaust gas aftertreatment system having an exhaust gas aftertreatment component, wherein exhaust gas formed in the motor during combustion of fuel is guided via the exhaust gas aftertreatment system for cleaning, includes: determining an exhaust gas actual value that depends upon an actual value of a nitrogen dioxide fraction in the exhaust gas upstream of the exhaust gas aftertreatment component; and changing at least one operating parameter for the motor such that the actual value of the nitrogen dioxide fraction is brought closer to a corresponding reference value for the nitrogen dioxide fraction.

An exhaust treatment system includes an SCRF device, a reductant delivery system, and an SCR storage module. The SCRF device includes a filter portion having a washcoat formed thereon that defines a washcoat thickness (WCT). The reductant delivery system is configured to inject a reductant that reacts with the washcoat based on a reductant storage model. The SCR storage module is in electrical communication with the reductant delivery system to provide the reductant storage model the amount of reductant to be injected based on the reductant storage model. The exhaust treatment system further includes a WCT compensation module configured to electrically communicate a WCT compensation value to the SCR storage module. The SCR storage module modifies the reductant storage model according to the WCT compensation value such that the amount of ammonia that slips from the SCRF device is reduced thereby increasing a storage efficiency of the SCRF device.

A control device of an internal combustion engine is configured to perform a fuel cut-off control and an abnormality diagnosis control. A heating device for heating an element of an air-fuel ratio sensor is controlled by making an element temperature of the air-fuel ratio sensor become a target element temperature. The target element temperature of the air-fuel ratio sensor during a high temperature control period from a time when a prescribed high temperature control begins after a start of the internal combustion engine to a time when the prescribed high temperature control is completed after completion of the abnormality diagnosis control of the air-fuel ratio sensor is set to be higher than the target element temperature outside the high temperature control period.

An apparatus includes a processing circuit structured to receive a first signal indicative of an upstream air-fuel equivalence ratio from a first sensor positioned upstream of an intake of a catalyst, receive a second signal indicative of a downstream air-fuel equivalence ratio from a second sensor positioned downstream of the intake of the catalyst, determine an actual oxygen storage capacity of the catalyst based at least in part on the received first signal and the received second signal, compare the actual oxygen storage capacity to a maximum storage capacity, and provide a fault signal in response to the actual oxygen storage capacity exceeding the maximum storage capacity. The apparatus also includes a notification circuit structured to provide a notification indicating that the second sensor is faulty in response to receiving the fault signal.