A method for estimating a quality of reductant in an engine aftertreatment system for an engine using a virtual sensor, the method comprising: determining whether an enablement condition is met, wherein the enablement condition is one or more of: a reductant fill condition determined based on data received from one or more float sensors associated with the engine; a machine start condition determined based on machine speed data obtained from a speed sensor associated with the engine; and/or a rationality check condition determined based on data associated with a fault of one or more sensors associated with the engine; upon determining that the enablement condition is met, receiving NOx measurement data obtained from at least one NOx sensor; generating a reductant quality value based on the NOx measurement data; and outputting a reductant quality determination based on the reductant quality value.

A method for ascertaining an exhaust gas composition of an exhaust gas of an internal combustion engine with regard to an ammonia fraction and a nitrogen oxides fraction in an exhaust gas system including an SCR catalytic converter. The method includes detecting, using a sensor, a first signal whose magnitude is a function of the nitrogen oxides fraction of the exhaust gas upstream from the SCR catalytic converter, detecting using a sensor a second signal whose magnitude is a function of the ammonia fraction and the nitrogen oxides fraction of the exhaust gas downstream from the SCR catalytic converter, storing the two signals over an observation period, and ascertaining the ammonia fraction and optionally the nitrogen oxides fraction of the exhaust gas downstream from the at least one SCR catalytic converter using a calculation rule that uses the two signals during the observation period as input variables.

An exhaust catalyst management apparatus to be applied to a vehicle includes a differential pressure sensor and one or more processors. The differential pressure sensor detects an accumulation state of an exhaust-containing substance in a catalyst device. The one or more processors are coupled to the differential pressure sensor and a vehicle outside sensor. The one or more processors determine whether or not travel environment is suited to carrying out an output control for removal, based on a result of the detection of surroundings of the vehicle by a vehicle outside sensor. Upon determining that the travel environment is suited to carrying out the output control for removal, the one or more processors carry out the output control for removal, while the vehicle is traveling, in accordance with a result of the determination of the accumulation state of the exhaust-containing substance in the catalyst device.

A catalyst deterioration detection device is provided to detect deterioration of a catalyst provided in an exhaust passage of an internal combustion engine. The catalyst deterioration detection device includes a storage device and processing circuitry. The storage device stores map data specifying a mapping that uses time series data of an excess amount variable in a first predetermined period and time series data of a downstream detection variable in a second predetermined period as inputs to output a deterioration level variable. The processing circuitry executes an acquisition process that acquires data, a deterioration level variable calculation process that calculates a deterioration level variable of the catalyst based on an output of the mapping using the data acquired by the acquisition process as an input. The map data includes data that is learned through machine learning.

A catalyst deterioration detection device is provided to detect deterioration of a catalyst provided in an exhaust passage of an internal combustion engine. The catalyst deterioration detection device includes a storage device and processing circuitry. The storage device stores map data specifying a mapping that uses time series data of an excess amount variable in a first predetermined period and time series data of a downstream detection variable in a second predetermined period as inputs to output a deterioration level variable. The processing circuitry executes an acquisition process that acquires data, a deterioration level variable calculation process that calculates a deterioration level variable of the catalyst based on an output of the mapping using the data acquired by the acquisition process as an input. The map data includes data that is learned through machine learning.

Disclosed is a method for adapting control of a reducing agent dosing unit in a reducing agent provision system for emission control of a combustion engine. Characteristics relating to pressure variations associated with a dosing cycle are used for determining a first time period and a second time period. The time periods relate to a delay between activation of dosing and de-activation of dosing, respectively. The first time period and second time period are used for adapting operation of said reducing agent dosing unit.

A method includes: interpreting first oxygen data acquired by a first nitrous oxide (NOx) sensor indicative of a first amount of oxygen in an exhaust flow at a location in or proximate to an exhaust aftertreatment system, wherein the exhaust aftertreatment system is in exhaust gas receiving communication with an engine; estimating an amount of oxygen in the exhaust flow entering the exhaust aftertreatment system from the engine based on engine operation data; and, determining that the NOx sensor is faulty based on determining that a difference between the first amount of oxygen and the estimated amount of oxygen is greater than a threshold value.

Methods and systems are provided for improving catalyst function during an engine cold-start. In one example, at key-off, a duration elapsed till a subsequent key-on is predicted based on drive history and spatial awareness data. Then, based on the duration, an identity and order of operating one or more catalyst heating devices is selected.

Methods and systems are provided for diagnostics of a gasoline particulate filter in an exhaust system. In one example, a method may include indicating degradation of a hose coupled across a particulate filter responsive to a difference between a first differential pressure and a second differential pressure being greater than a threshold, the first differential pressure measured by a differential pressure sensor positioned in the hose responsive to a downstream exhaust tuning valve being fully open, the second differential pressure measured by the differential pressure sensor responsive to the exhaust tuning valve being fully closed.

In a method for heating an exhaust system of a combustion engine of a motor vehicle, the exhaust system comprises at least two components for exhaust gas cleaning. For at least one component, a temperature regulation is provided for heating the component while using a heating operation mode. For the heating of the exhaust system, a heating operation is used via a pulse control with heating pulses (101) and heating pauses (102), which switches between a heating operation mode and a normal operation without heating measures.