Abstract:
In a control apparatus for an internal combustion engine in which processing of regenerating the NOx storage capacity of an NSR catalyst is carried out in accompany with processing of diagnosing an abnormality in an exhaust gas purification device including the NSR catalyst, the present invention is intended to suppress the fluctuation of torque at the time of regenerating the NOx storage capacity of the NSR catalyst, and to terminate abnormality diagnostic processing quickly. According to the invention, by setting an engine air fuel ratio, which has been set to a lean air fuel ratio before the processing of regenerating the NOx storage capacity of the NSR catalyst is started, to a weak lean air fuel ratio which is lower than a basic lean air fuel ratio and higher than a stoichiometric air fuel ratio, it becomes possible to suppress the fluctuation of torque at the time of regeneration processing being started, and to terminate abnormality diagnostic processing at an early period of time.
Abstract:
An exhaust treatment system (200) is provided including: a selective catalyst reduction (SCR) unit (108); a reducing agent dispensing unit (108) configured to introduce a reducing agent into the exhaust; a first nox sensor (202) upstream of the scr unit (108); a second nox sensor (206) at a location downstream of the scr unit (108); a first temperature sensor (204) at a location upstream of where the reducing agent is introduced into the exhaust; a second temperature sensor (208) at a location downstream of where the reducing agent is introduced into the exhaust and upstream of the scr unit (108); and a controller (210) configured to determine a reductant quality (300) indicator according to a ΝΟχ differential between the first nox sensor (202) and the second nox sensor (206) relative to a predicted ΝΟχ differential and a temperature differential between the first temperature sensor (204) and the second temperature sensor (208) relative to a predicted temperature differential.
Abstract:
Engine exhaust gas feedstream NOx emissions aftertreatment includes a three-way catalytic device connected upstream of an ammonia-selective catalytic reduction device including a base metal. Engine operation can be modulated to generate an engine-out exhaust gas feedstream that converts to ammonia on the three-way catalytic device. The ammonia is stored on the ammonia-selective catalytic reduction device, and used to reduce NOx emissions in the exhaust gas feedstream.
Abstract:
Die Erfindung betrifft ein Verfahren zur Ermittlung einer NO 2 -Konzentration und/oder eines Konzentrationsverhältnisses von NO 2 und NO in einem Abgasstrang einer Verbrennungseinrichtung, insbesondere einer Brennkraftmaschine. Bei dem Verfahren wird ein in Bezug auf NO 2 und NO empfindlicher NOx-Sensor eingesetzt, welcher ein NOx-Ausgangssignal bereitstellt, das mit einer durch die Summe der Konzentrationen von NO 2 und NO repräsentierten NOx-Konzentration korreliert. Zur Ermittlung der NO 2 -Konzentration und/oder des Konzentrationsverhältnisses von NO 2 und NO wird das NOx-Ausgangssignal (S) eines ersten NOx-Sensors (5), der stromauf eines im Abgasstrang (1) angeordneten Abgasbehandlungselements mit Fähigkeit zur Umsetzung von NO zu NO 2 und/oder zur Umsetzung von NO 2 zu NO angeordnet ist, mit dem NOx-Ausgangssignal (S) eines zweiten NOx-Sensors (6), der stromab des Abgasbehandlungselements (2) angeordnet ist, verglichen.
Abstract:
A fuel reformer (12) is configured in an exhaust line upstream of a lean NOx trap (13). To desulfate the lean NOx trap (13), over a first period, fuel is provided to the exhaust to make the exhaust rich. While producing reformate, the reformer (12) is allowed to heat to a relatively large extent, typically at least about 75°C. Before the reformer (12) overheats, the provision of fuel is reduced and typically stopped entirely for a second period, over which the reformer (12) cools. The heating and cooling periods are repeated to complete the desulfation process. The reduced efficiency of operating the reformer (12) over an extended temperature range is more than compensated for by the benefits of extending the rich pulse
Abstract:
The invention relates to a method for controlling a NOX storage catalyst by means of a NOX-sensitive measuring device, especially a NOX sensor, that is arranged downstream in relation to the NOX storage catalyst which is arranged in an exhaust gas channel of a combustion engine. According to the invention, a reference time (t0) is determined by means of a signal path of the NOX-sensitive measuring device (18) after the combustion engine (10) has been switched into a lean operating mode. Said reference time is used as the timely starting point for controlling processes being related to the NOX storage catalyst (16). The invention also relates to a device for carrying out the method. According to said device, means are provided by means of which the following procedure steps can be carried out: determining a reference time (t0) by means of a signal path (SV) of the NOX-sensitive measuring device (18) after regeneration of the NOX storage catalyst (16) and using the reference time (t0) as the timely starting point for controlling processes of the NOX storage catalyst (16).