A controller 1 includes a calculation unit 10 that receives the current sensor value A1 of the vehicle and calculates an injection amount based on the current sensor value A1 and a target value of the ammonia adsorption amount of the selective reduction catalyst 105 so that the ammonia adsorption amount approaches the target value, and a prediction unit 20 that receives the current sensor value B1 and calculates a corrected target value by future prediction based on the current sensor value B1. The calculation unit 10 calculates the injection amount based on the corrected target value calculated by the prediction unit 20.

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 gas aftertreatment system for an internal combustion engine has an exhaust system that can be connected to an outlet of the internal combustion engine. A three-way catalytic converter that is situated close to the engine and, downstream from the three-way catalytic converter that is situated close to the engine, a second catalytic converter and a particle reduction device are arranged in the direction in which an exhaust gas of the internal combustion engine flows through an exhaust gas channel of the exhaust system. A fuel injector is arranged on the exhaust gas channel so as to inject fuel downstream from the three-way catalytic converter that is situated close to the engine and upstream from the second catalytic converter, and the exhaust system comprises a secondary air system with which secondary air can be blown into the exhaust gas channel downstream from the three-way catalytic converter that is situated close to the engine and upstream from the second catalytic converter.

A control device for an internal combustion engine including an upstream cleaning device and a downstream cleaning device that are provided in an exhaust gas passage and a temperature sensor that detects a temperature of exhaust gas between the upstream cleaning device and the downstream cleaning device is provided. The control device includes a first temperature estimating unit configured to estimate a temperature of the downstream cleaning device from the temperature of exhaust gas detected by the temperature sensor and a second temperature estimating unit configured to estimate a temperature of the downstream cleaning device without using the temperature of exhaust gas detected by the temperature sensor. An abnormality determining process for the upstream cleaning device is performed when at least the temperature of the downstream cleaning device estimated by the second temperature estimating unit is equal to or greater than a predetermined threshold value.

Systems and methods for controlling a gasoline urea selective catalytic reductant catalyst are described. In one example, an observer is provided that corrects an estimate of an amount of NH.sub.3 that is stored in a SCR. The amount of NH.sub.3 that is stored in the SCR is a basis for generating additional NH.sub.3 or ceasing generation of NH.sub.3.

The present invention is applied to an exhaust system provided with a three-way catalyst and a NOx catalyst which are provided in an exhaust passage of an engine and to which sulfur components in exhaust adhere and release the attached sulfur components by rich components in exhaust, and NOx sensors provided downstream of the catalysts. The NOx sensor is a limiting current type sensor. It is determined whether a sulfur release state is present in which a sulfur component is released from the three-way catalyst and the NOx catalyst. When it is determined that it is in the state of sulfur release, reaction suppression processing for suppressing the reaction between oxygen and sulfur components in the pump cell electrodes and the monitor cell electrodes of the NOx sensors is performed.

A control module for an aftertreatment system that includes a selective catalytic reduction (SCR) catalyst and an oxidation catalyst, comprises a controller configured to be operatively coupled to the aftertreatment system. The controller is configured to determine an actual SCR catalytic conversion efficiency of the SCR catalyst. The controller determines an estimated SCR catalytic conversion efficiency based on a test sulfur concentration selected by the controller. In response to the estimated SCR catalytic conversion efficiency being within a predefined range, the controller sets the test sulfur concentration as a determined sulfur concentration in a fuel provided to the engine. The controller generates a sulfur concentration signal indicating the determined sulfur.

A controller for an aftertreatment system coupled to an engine is configured to: in response to receiving an engine shutdown signal, determine an estimated amount of ammonia stored on a selective catalytic reduction (SCR) catalyst included in the aftertreatment system; in response to determining that the estimated amount of ammonia stored in the SCR catalyst is less than an ammonia storage threshold, cause flow of a heated gas towards the SCR catalyst; cause insertion of reductant into an exhaust gas flowing through the aftertreatment system; and in response to determining that the estimated amount of ammonia stored in the SCR catalyst is equal to or greater than the ammonia storage threshold, cause shutdown of the engine.

Methods and systems are proposed for controlling a temperature of exhaust gases generated by the engine by operating an E-Turbo of the vehicle. In one embodiment, a method is provided, comprising increasing a power generated by an electric machine mechanically coupled with an exhaust turbine of an E-Turbo of a vehicle or adjusting an engine power based on a speed of the exhaust turbine and an air-fuel ratio (AFR) of an engine of the vehicle of the engine responsive to the speed of the exhaust turbine increasing above a threshold turbine speed. By increasing or decreasing the power generated by the electric machine and/or adjusting the engine power, the temperature of the exhaust gas may be maintained within a threshold temperature range where an efficiency of an aftertreatment system may be maximized, thereby reducing an emissions of the vehicle.

A method (200) for ascertaining a catalytic converter state is proposed, wherein an exhaust-gas catalytic converter (130) is monitored on the basis of a catalytic converter model. Here, the catalytic converter model is adapted (250) in a manner dependent on measured values detected by means of one or more sensors (145, 147), wherein a frequency and/or a degree of the adaptation of the catalytic converter model is detected (260). The catalytic converter state is ascertained (270) as non-critical if the frequency and/or the degree of the adaptation do not exceed a predeterminable threshold value or is ascertained (270) as critical if the frequency and/or the degree of the adaptation exceed the predeterminable threshold value.