In a process for adapting an amount of reducing agent for a removal of nitrogen oxides from the gases in an exhaust line, a first alignment of the amounts of nitrogen oxides measured by upstream and downstream sensors is performed without injection of agent and with a catalyst of the system emptied of ammonia. A second alignment of the estimated reduction of nitrogen oxides with the measured reduction is performed by a difference between amounts of nitrogen oxides upstream and downstream during a substoichiometric injection of reducing agent without creating a store of ammonia in a catalyst of the system with a first correction of the amount of agent. A third alignment of an estimated efficiency of retaining nitrogen oxides with a efficiency measured by the sensors is performed, this third alignment taking place via a second correction of the amount of reducing agent injected as an adaptive correction.

The present disclosure relates to an exhaust gas aftertreatment system and method for controlling same. The exhaust gas aftertreatment system comprises: a reductant dosing device; a selective catalytic reduction device arranged downstream of the reductant dosing device; an ammonia slip catalyst arranged downstream of the SCR device; a feedback NOx sensor arranged downstream of the SCR device and upstream of the ammonia slip catalyst; a tailpipe NOx sensor arranged downstream of the ammonia slip catalyst; and a control device configured for: providing an initial dosing of reductant from the reductant dosing device; obtaining a feedback signal from the feedback NOx sensor and a tailpipe NOx signal from the tailpipe NOx sensor; and adjusting the dosing of reductant until the feedback signal exceeds the tailpipe NOx signal by a value within a predetermined positive interval.

A recycling loop configuration of an exhaust gas aftertreatment system decreases a level of system-out NO.sub.x emissions of an engine. An apparatus including the configuration has an exhaust gas recycling system having a closed gas recycling loop system configured to heat gas circulating within the loop, and a blower for circulating gas within the loop. A method for operating the engine includes preheating at least one aftertreatment component of an exhaust gas aftertreatment system of the engine by exposing the component to heated gas circulating in a closed gas recycling loop.

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).

Systems and methods for controlling a dosing of reductant for an internal combustion engine system including a catalyst are disclosed. The method includes measuring a value indicative of inlet temperature of the catalyst. When the inlet temperature is less than or equal to a first threshold, the method includes adjusting the dosing of reductant according to a first process. When the inlet temperature is greater than the first threshold, the method includes adjusting the dosing of reductant according to a second process, the second process being different than the first process.

An aftertreatment system includes a selective catalytic reduction (SCR) system, a heater, and a controller that determines a rise in temperature of exhaust gas at an outlet of the heater for a plurality of power levels, predicts a first temperature of the exhaust gas at the outlet of the heater based on the rise in temperature, predicts a second temperature of the exhaust gas at a location of the SCR system based on the first temperature, compares the second temperature for each of the plurality of power levels with a target temperature of the exhaust gas at the inlet of the SCR system, selects one of the plurality of power levels based on the comparison, and adjusts operation of the heater based on the selected one of the plurality of power levels to achieve the target temperature of the exhaust gas at the inlet of the SCR system.

The present disclosure relates to a method for determining urea feeding in an exhaust gas aftertreatment system (100,200), the exhaust gas aftertreatment system (100,200) being connectable to an internal combustion engine (101,201) operating under an engine operating condition, the system (100,200) comprising a first Selective Catalytic Reduction (SCR1) system comprising a first selective reduction catalyst (SCR1c) and a first doser (103,203) configured for feeding urea upstream the SCR1 system, at least one Particulate Filter (PF) downstream the SCR1 system or as a substrate for the SCR1c and a second Selective Catalytic Reduction (SCR2) system downstream the PF, the SCR2 system comprising a second selective reduction catalyst (SCR2c) and a second doser (104,204) configured for feeding urea upstream the SCR2c, the method comprising the steps of estimating the amount of particles in the PF; and determining the amount of urea to be fed by the respective first and second doser (4,5) based on the engine operating condition and such that: a) the amount of particles in the PF is within a predefined particle amount range, and, b) the NOx level of the exhaust gas exiting the SCR2 system is within a predetermined NOx level range. The present disclosure also relates to an exhaust gas aftertreatment system (100,200) and a vehicle comprising the exhaust gas aftertreatment system (100,200), a computer program comprising program code means for performing the steps of the method, a computer readable medium carrying a computer program comprising program code means for performing the steps of the method and a control unit for controlling urea feeding in the exhaust gas aftertreatment system (100,200).

The disclosure relates to a self-adaptive oil spraying control system and method for a biodiesel engine. The control system includes an exhaust pipe, a gas sensor, a control module and an oil sprayer, wherein the exhaust pipe is connected to the oil sprayer, the gas sensor is mounted in the exhaust pipe, and the gas sensor and the oil sprayer are connected to the control module respectively. According to the control method, a main spray advance angle of the engine is subjected to closed-loop control directly through comparison between an idling steady state NO.sub.x emission signal and an idling steady state NO.sub.x emission value of pure diesel when the engine uses the biodiesel, so that emission of NO.sub.x in the exhaust is reduced. Compared with the prior art, the disclosure has the advantages of no need of detecting a biodiesel ratio, high efficiency, good effect and the like.

Provided is a control device configured to be able to execute a forced regeneration process in an engine which includes a DOC and DPF disposed in an exhaust passage of the engine, and a temperature increase unit including an exhaust throttle valve, for increasing a temperature of each of the DOC and the DPF. The forced regeneration process includes a first temperature increase process of controlling the temperature increase unit such that the temperature of the DOC is increased to a first temperature, and a second temperature increase process of controlling the temperature increase unit such that the temperature of the DPF is increased to a second temperature which is higher than the first temperature after completion of the first temperature increase process. The control device includes a valve opening/closing operation execution part configured to cause the exhaust throttle valve to execute a valve opening/closing operation of increasing an opening degree of the exhaust throttle valve to be greater than a predetermined opening degree for a predetermined time, when the forced regeneration process is switched from the first temperature increase process to the second temperature increase process.

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.