A converter containing a NOx absorbing and reducing catalyst is disposed in the exhaust passage of an internal combustion engine. The upstream half portion (portion of the inlet side) of the substrate of the NOx absorbing and reducing catalyst in the converter carries the oxygen storage component that absorbs oxygen in the exhaust gas when the air-fuel ratio of the exhaust gas is lean and releases the absorbed oxygen when the air-fuel ratio of the exhaust gas flowing in is rich in addition to carrying the NOx absorbing and reducing catalyst. After NOx is absorbed by the NOx absorbing and reducing catalyst as a result of operating the engine at a lean air-fuel ratio, the engine is operated at a rich air-fuel ratio, so that NOx is released from the NOx absorbing and reducing catalyst and is purified by reduction. Here, oxygen is released from the oxygen storage component carried by the upstream half portion of the substrate and is reacted with the H 2 and CO components in the exhaust gas, so that the temperature of the NOx absorbing and reducing catalyst is raised within short periods of time due to the heat of reaction. Therefore, the catalyst exhibits increased activity and the NOx absorbing and reducing catalyst exhibits improved NOx purification capability.

Exhaust gas purification device for an internal combustion engine

An exhaust gas aftertreatment installment and associated exhaust gas aftertreatment method utilizes a nitrogen oxide storage catalytic converter and an SCR catalytic converter. A particulate filter is provided upstream of the nitrogen oxide storage catalytic converter or between the latter and the SCR catalytic converter or downstream of the SCR catalytic converter. The time of regeneration operating phases of the nitrogen oxide storage catalytic converter can be determined as a function of the nitrogen oxide content of the exhaust gas downstream of the nitrogen oxide storage catalytic converter or of the SCR catalytic converter and/or as a function of the ammonia loading of the latter. Moreover, a desired ammonia generation quantity can be determined for a respective regeneration operating phase. The installation and method are adopted for use for motor vehicle internal combustion engines and other engines which are operated predominantly in lean-burn mode.

Exhaust Gas Aftertreatment Installation and Method

One aspect of the invention relates an exhaust treatment system having an SCR reactor following a NOx adsorber. Syn gas is used to regenerate the NOx adsorber. Another aspect relates to an LNT/SCR provided with an ammonia source separate from the LNT. A further aspect relates to a system comprising first and second LNTs and one or more SCRs downstream of the LNTs. A still further aspect relates to a device comprising first and second NOx adsorbers contained in a single housing. Another aspect relates to coating a surface of a moving part in an exhaust system with an oxidation catalyst to mitigate fouling. Additional aspects of the invention relate to strategies for controlling one or more of the time to initiate a regeneration cycle, the time to terminate a regeneration cycle, and the reductant injection rate during regeneration of LNT/SCR exhaust treatment systems.

Hybrid catalyst system for exhaust emissions reduction

A first cylinder and a second cylinder are provided. A first exhaust pipe is connected to the first cylinder and a second exhaust pipe is connected to the second cylinder. A communicating pipe connects together an intermediate portion of the first exhaust pipe with an intermediate portion of the second exhaust pipe. An exhaust gas control catalyst is arranged in the second exhaust pipe downstream of the portion to which the communicating pipe is connected. Exhaust gas amount reducing devices are provided which reduce the amount of exhaust gas that flows from the first exhaust pipe into the second exhaust pipe through the communicating pipe during execution of rich/lean burn control which performs combustion with an air-fuel ratio of an air-fuel mixture that is richer than the stoichiometric air-fuel ratio in one of the first cylinder and second cylinder and performs combustion with an air-fuel ratio of an air-fuel mixture that is leaner than the stoichiometric air-fuel ratio in the other cylinder.

Exhaust Gas Control Apparatus for Internal Combustion Engine

An internal combustion engine comprises an intake tract in which a throttle valve is disposed. The engine also comprises a camshaft which acts on gas inlet valves associated with respective cylinders. A phase-adjustment device is used to adjust a phase between the camshaft and a crankshaft. A desired air mass flow in a combustion chamber of the cylinder is determined depending on a charge requirement requested by the driver. The desired air mass flow is adjusted by varying the phase between the camshaft and the crankshaft if the desired air mass flow can be adjusted by varying the phase while substantially maintaining an actual pressure difference upstream and downstream of the throttle valve. Otherwise, the desired air mass flow is adjusted by varying the opening angle of the throttle valve.

Method and device for controlling an internal combustion engine

Die Erfindung betrifft einen Verbrennungsmotor (1) mit einem Abgassystem, welches eine Vorkatalysatoreinrichtung (3) und eine stromab der Vorkatalysatoreinrichtung (3) angeordnete Hauptkatalysatoreinrichtung (4) aufweist, und mit einer Kraftstoffregelungs-Vorrichtung (11) zur Gemischregelung in Abhangigkeit von dem Signal von zumindest einem im Abgas angeordneten Sauerstoffsensor. Erfindungsgemass ist ein erster Sauerstoffsensor (5) stromab der Vorkatalysatoreinrichtung (3) und stromauf der Hauptkatalysatoreinrichtung (4) angeordnet, dessen Signal der Kraftstoffregelungs-Vorrichtung (11) zur Gemischregelung zugefuhrt wird. Ferner umfasst die Erfindung ein Verfahren zum Betrieb eines erfindungsgemassen Verbrennungsmotors.

Verbrennungsmotor und verfahren zum betrieb eines verbrennungsmotors mit einer kraftstoffregelungsvorrichtung

Die Erfindung betrifft ein Verfahren zum Betreiben einer Brennkraftmaschine, insbesondere eines Kraftfahrzeuges, mit einer Abgasanlage mit Abgasreinigungssystem, wobei ein Motorlambdawert in Abhangigkeit von einer modellierten oder gemessenen Temperatur an wenigstens einer kritischen Stelle der Abgasanlage derart vom Normalbetrieb abweichend auf einen temperaturabhangigen Motorlambdawert eingestellt wird, das eine Abgastemperatur abgesenkt wird, wenn die ermittelte Temperatur an der wenigstens einen Stelle der Abgasanlage einen vorbestimmten ersten Temperaturwert uberschreitet. Hierbei wird der Motorlambdawert erst dann zur Absenkung der Abgastemperatur vom Wert fur den Normalbetrieb in einen temperaturabhangigen Motorlambdawert verandert, wenn die Mestemperatur den vorbestimmten ersten Temperaturwert fur einen vorbestimmten Zeitraum uberschritten hat.

Verfahren zum Schutz von Abgasreinigungssystemen von Brennkraftmaschinen vor thermischer Überbelastung

The invention relates to a method for desulphatizing an NOx accumulator or an NOx accumulator catalytic converter installed downstream in an internal combustion engine operated with a lean mixture, wherein the internal combustion engine is operated in several rich-lean mixture cycles after a predetermined desulphatization temperature has been set. In the rich mixture cycles, the lambda value drops to less than 0.985, whereby values in the range of approximately 0.95 are preferred, since the emission of accumulated sulfur in the form of sulfur dioxide is ostensibly accelerated. Undesired hydrogen sulfide formation arising as a result of the annoyance caused by bad smell is delayed and occurs at a clearly slower rate. The duration of reduction is so short that traceable emissions of hydrogen sulfide can no longer be detected while practically total desulphatization of the NOx accumulator catalytic converter is ensured by operation in cycles. The rich-lean mixture phases of the cycles last approximately 2-10 s or 2-6 s so that ostensibly shorter regeneration times with higher lambda values are obtained in comparison with conventional methods while at the same time consumption is correspondingly reduced.

METHOD FOR DESULPHATIZING AN NO x? ACCUMULATOR CATALYTIC CONVERTER

The invention relates to an internal combustion engine (1) comprising an exhaust system which is provided with a pre-catalyst device (3) and a main catalyst device (4) arranged downstream of said pre-catalyst device (3), and a fuel regulating device (11) for regulating the mixture according to the signal emitted by at least one oxygen sensor arranged in the exhaust system. According to the invention, a first oxygen sensor (5) is arranged downstream of the pre-catalyst device (3) and upstream of the main catalyst device (4), the signal of said sensor being supplied to the fuel regulating device (11) for regulating the mixture. The invention also relates to a method for operating one such internal combustion engine.

Internal combustion engine and method for operating an internal combustion engine comprising a fuel regulating device

Process for reduction of emission of pollutants from internal combustion engine (12) with spark ignition with at least one catalyst in exhaust system to convert and/or store exhaust gases from engine The ignition angle (ZW) of at least one cylinder (14) is adjusted relative to base angle (ZW0) as function of activity of conversion and/or storage of catalyst(s) (18, 28, 30) An Independent claim is also included for the catalyzed exhaust system involved

Process and installation of the reduction of emission of pollutants from internal combustion engines involves system of monitoring condition of exhaust catalyst by adjustment of ignition angle of cylinder

Ekkehard Pott

Papers

Verbrennungsmotor und verfahren zum betrieb eines verbrennungsmotors mit einer kraftstoffregelungsvorrichtung

Verfahren zum Schutz von Abgasreinigungssystemen von Brennkraftmaschinen vor thermischer Überbelastung

METHOD FOR DESULPHATIZING AN NO x? ACCUMULATOR CATALYTIC CONVERTER

Internal combustion engine and method for operating an internal combustion engine comprising a fuel regulating device

Process and installation of the reduction of emission of pollutants from internal combustion engines involves system of monitoring condition of exhaust catalyst by adjustment of ignition angle of cylinder