The disclosure relates to a method for optimizing the state of a catalytic converter in a vehicle with a diesel engine when parking the vehicle, the method comprising establishing that a switch-off process for switching off the diesel engine has been initiated, increasing an NH3 feed rate to a first value in order to store a surplus of NH3 in the catalytic converter, stopping the NH3 feed when the speed of the diesel engine falls below a speed threshold or a measured NH3 emission exceeds an emission threshold, and completing the switch-off process. The disclosure also relates to an engine controller and to a computer program.

A system for determining an exhaust flow rate of an exhaust gas produced by an engine comprises a first sensor configured to measure an amount of NOx gases in the exhaust gas. A controller is communicatively coupled to the first sensor. The controller is configured to receive a first sensor signal from the first sensor. The controller is also configured to receive a fuel rate signal corresponding to a rate of fuel consumption by the engine. The controller is configured to determine an air-fuel ratio from the first sensor signal and determine a fuel rate from the fuel rate signal. Furthermore, the controller is configured to determine the exhaust flow rate from the air-fuel ratio and the fuel rate.

A process for testing a plurality of components of an exhaust gas aftertreatment system (100) is disclosed, wherein the plurality of components comprises a first SCR catalyst and at least one further SCR catalyst arranged downstream of the first SCR catalyst in the flow direction of exhaust gas to be passed through the exhaust gas aftertreatment system, a first NOx sensor assigned to the first SCR catalyst and at least one further NOx sensor and a first DeNOx element assigned to the first SCR catalyst and at least one further DeNOx element and wherein the process comprises at least the following steps: conditioning the SCR catalysts, testing the NOx sensors, testing the DeNOx systems testing a storage capacity for the reductant of the SCR catalysts.

A system has a pump and an injector coupled to the pump. The system further comprises a controller coupled to the pump and the injector. The controller is structured to: determine a change of reductant flow relative to a change of pump rate of the pump; and generate a status command indicative of at least one of an under-restricted injector or an over-restricted injector in response to the determination of the change of reductant flow relative to the change of pump rate of the pump.

A method for operating a motor vehicle having an exhaust gas aftertreatment device involves an on-board electronic computing device receiving consumption information characterizing consumption of a reducing agent by the exhaust gas aftertreatment device and tank information characterizing a filling level of a reducing agent tank. Tank information is evaluated together with the consumption information with regard to a divergence, and upon determination of the divergence between the tank information and the consumption information, error information is stored in a blockchain characterizing the motor vehicle, and an action of the motor vehicle is triggered.

A method includes: providing a SCR system comprising a SCR catalyst; heating the SCR system to a temperature greater than 500 degrees Celsius for a predetermined time so as to increase sulfur resistance of the SCR catalyst; and installing the SCR system in an aftertreatment system.

An aftertreatment system comprises a SCR system, a reductant injector operatively coupled to the SCR system, and a reductant insertion assembly operatively coupled to the reductant injector. The reductant insertion assembly comprises a pump configured to pump the reductant through the reductant injector. A controller is operatively coupled to the reductant insertion assembly and configured to receive predetermined calibration values of the pump corresponding to delivery of a reductant by the pump through a calibration injector. The controller determines a desired flow rate value of the reductant into the SCR system. The controller determines an insertion time of the reductant injector for delivering the reductant through the reductant injector based on the desired flow rate value, a pump operating parameter value of the pump and the predetermined calibration values, and activates the reductant injector for the insertion time.

A method for controlling an SCR catalytic converter (20, 30), comprising detecting (200) concentration values (314, 324; 414, 424) in the exhaust gas downstream of the catalytic converter (20), wherein at least one concentration value for NH.sub.3 and one concentration value for NO.sub.x is detected; calculating (202) modeled concentration values (316, 322; 416, 422) for NH.sub.3 and NO.sub.x downstream of the catalytic converter on the basis of a catalytic converter model, wherein the model comprises an aging parameter (342, 442) which at least partially describes aging of the modeled catalytic converter; comparing (208) the detected concentration values with the modeled concentration values; and, in a manner dependent on the result of the comparison, changing the aging parameter (342, 442) of the model and/or changing a predefined dosing quantity for a reducing agent in the SCR catalytic converter.

A method of adjusting the dosage of a reductant for an SCR catalyst, comprising: determining (110) an expected temperature profile in at least one axial section of the catalyst (70) for a defined period of time (t.sub.Sim); firstly simulating (120) the resulting amount of reductant beyond the at least one section of the catalyst with a first defined dosage of the reductant depending on the expected temperature profile determined; comparing the first simulated amount of reductant with a limit; depending on the result of the comparison, choosing a second defined dosage and secondly simulating (130, 160) a resulting amount of reductant beyond the at least one section of the catalyst (70) with the second dosage; comparing the second simulated amount of reductant with the limit; and adjusting (140, 150, 170, 180, 190, 195) the dosage for injection of the reductant into the catalyst based on the first and/or second comparison.

The invention relates to a control method that allows the mean quantity of nitrogen oxides per kilometer covered emitted by a vehicle fitted with an internal combustion engine associated with a post-treatment system to be kept below a predefined fixed threshold, for any journey made by the vehicle. The mean quantity emitted over a fixed elementary distance that has just been covered by the vehicle is calculated iteratively, together with a long-term conformity factor which is equal to the mean quantity emitted over the entire distance covered since the start of the journey. When it is found that the long-term conformity factor is above the threshold, the engine and/or the post-treatment system is regulated in such a way as to obtain, over the next fixed elementary distance, a mean quantity of nitrogen oxides per kilometer that is lower than the threshold value FC, for example equal to 90% of the threshold, whatever the engine operating point. Thus, the long-term conformity factor converges towards the threshold.