A hybrid electric vehicle and a catalyst heating control method are configured to select a point in time at which catalyst heating control is performed and to perform a follow-up measure based on the selected point in time. The catalyst heating control method includes performing mode switching from a first mode in which only a drive motor is used as a driving source to a second mode in which an engine is driven in a state in which a drive shaft and the engine are disconnected from each other to start heating of a catalyst of the engine. When demand torque higher than a maximum output of the drive motor occurs before the catalyst heating is completed, the second mode is maintained until the demand torque is greater than the sum of the maximum output and a predetermined margin.

An urea injection control system for an internal combustion engine, specifically adapted to apply a scheme for decreasing a NOx level downstream of a selective catalytic reduction catalyst of an ICE related exhaust gas aftertreatment system. The present disclosure also relates to a corresponding computer implemented method and a computer program product.

An engine exhaust aftertreatment device includes a first exhaust treatment unit and/or a second exhaust treatment unit; the first exhaust treatment unit includes a first bypass pipeline and a first connection pipe provided between a DPF and an SCR; the second exhaust treatment unit comprises a second bypass pipeline and a second connection pipeline provided between a DOC and the DPF, one end of the second bypass pipeline being in communication with the turbine front exhaust pipe, and the other end of the second bypass pipeline being in communication with the second connection pipeline; when it is detected that an engine satisfies a starting condition of the first exhaust treatment unit, the first exhaust treatment unit starts; and when it is detected that the engine satisfies a starting condition of the second exhaust treatment unit, the second exhaust treatment unit starts.

The disclosure provides a method and a device for closed-loop control of a temperature of a component in an exhaust-gas tract of an internal combustion engine. The exhaust-gas tract has a temperature sensor arranged upstream of the component. The method includes providing a control circuit for the closed-loop control of the temperature of the component and detecting a measurement signal by the temperature sensor during the operation of the internal combustion engine. The measurement signal is characteristic of an exhaust-gas temperature. The measurement signal is used as a measured controlled variable for the control circuit for the closed-loop control of the temperature of the component. The method also includes determining a temperature model for the exhaust-gas temperature of the exhaust gas upstream of the component. The temperature model is used as a predictor for the control circuit. Also, a modeled controlled variable is provided from the temperature model.

A system comprising an aftertreatment system comprising: a catalyst member, and a first exhaust conduit upstream of the catalyst member; a first temperature sensor operatively coupled to the catalyst member; a flow sensor coupled to the first exhaust conduit; and a controller. The controller determines a temperature of the catalyst member, a flow rate of exhaust within the first exhaust conduit, and a space velocity of the exhaust within the catalyst member. The controller determines a first degradation value indicative of a degradation of the catalyst member. The controller determines a first difference between the first degradation value and a first degradation reference value and a second difference between the first degradation value and a second degradation reference value. After determining that the first difference is less than the second difference, the controller selects a first calibration metric. The controller determines a first efficiency value associated with the catalyst member.

A method for operating an internal-combustion engine having an exhaust gas catalyst, a first exhaust gas sensor upstream of the exhaust gas catalyst and a second exhaust gas sensor downstream of the exhaust gas catalyst. A fill level of an exhaust gas component that can be stored in the exhaust gas catalyst is determined using a theoretical catalyst model, into which, as the input value, a signal of the first exhaust gas sensor (a first signal); a signal of the second exhaust gas sensor (a second signal); and a target signal are provided. The target signal corresponds to the signal that would be expected at the determined fill level in the exhaust gas catalyst. The catalyst model is reinitiated when the deviation of the second signal from the target signal exceeds a predetermined threshold value. The fill level is also regulated, and an air-fuel mixture is adjusted.

Methods and systems are provided for an exhaust system. In one example, a method may include determining presence of a zone flow based on a comparison of a first exhaust sensor and a second exhaust sensor. The presence or absence of the zone flow may determine a rate at which an air-fuel ratio is adjusted.

An aftertreatment system for a diesel engine may include a diesel particulate filter configured for placement in fluid communication with the diesel engine to receive an exhaust flow. The system may also include a selective catalytic reduction system configured for arrangement downstream of the diesel particulate filter and a NO.sub.x sensor configured to measure a NO.sub.x concentration in the exhaust flow entering the selective catalytic reduction system. The system may also include a controller configured to estimate a ratio of NO.sub.2 to NO.sub.x downstream of the diesel particulate filter and based on a factor affecting the generation of NO.sub.2 upstream of the selective catalytic reduction system. The controller may also be configured to adjust the measured NO.sub.x concentration based on the ratio to provide an estimated actual NO.sub.x concentration and dose diesel exhaust fuel into the exhaust flow based on the estimated actual NO.sub.x concentration.

The invention proposes a method for operating a metering system (32) with a plurality of metering valves (34, 35) for an SCR catalyst system, in which opening times for the injection of reducing agent are calculated for the metering valves (34, 35) based on a metering amount requirement. In the calculations of the opening times, a metering-valve-specific adaptation factor is used, w herein a deviation (Δp) of a system pressure (p.sub.ist) in the metering system (32) from a target pressure (p.sub.soll) and a weighting factor are used for calculation of the metering-valve-specific adaptation factor. The weighting factor depends on a proportion (r.sub.34, r.sub.35) of the required metering amount ((formula (I)), (formula (II)) of the respective metering valve (34,35) in relation to a total metering amount ((formula (I)), (formula (II)) of all metering valves (34, 35).

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.