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

NO X conversion of exhaust gases from lean mixture engines such as Diesel engines is improved by providing a catalytic converter having three zones, the first zone containing an NO X storage material on a γ-aluminum oxide layer, the second zone having a layer with a noble metal, and the third zone containing an oxygen storage layer.

No exhaust emission control method and arrangement

Es wird ein Verfahren zur De-Sulfatierung eines einer mager betriebenen Brennkraftmaschine nachgeschalteten NOx-Speichers oder NOx-Speicherkatalysators beschrieben, bei dem die Brennkraftmaschine nach Einstellung einer vorbestimmten De-Sulfatierungstemperatur in mehreren Fett-Mager-Zyklen betrieben wird. Im fetten Bereich dieser Zyklen erfolgt eine Absenkung des Lambda-Wertes auf weniger als 0.985, wobei Werte im Bereich von etwa 0,95 bevorzugt werden, da hierdurch die Emission des eingelagerten Schwefels in Form von Schwefeldioxid merklich beschleunigt wird, wahrend die aufgrund der auftretenden Geruchsbelastigung unerwunschte Schwefelwasserstoffbildung erst zeitlich verzogert einsetzt und insgesamt deutlich langsamer ablauft. Die Dauer der Absenkung wird hierbei so kurz gewahlt, dass keine spurbare Emission von Schwefelwasserstoff mehr feststellbar ist, wahrend durch die zyklische Betriebsweise eine im wesentlichen vollstandige De-Sulfatierung des NOx-Speicherkatalysators gewahrleistet ist. Die Fett- und Magerzeiten der Zyklen betragen vorzugsweise 2 - 10 s bzw. 2 - 6 s, so dass sich merklich kurzere Regenerationszeiten als bei herkommlichen Verfahren mit hoheren Lambda-Werten ergeben, was letztendlich wiederum mit einer enstprechenden Verbrauchsminderung verbunden ist.

Verfahren zur De-Sulfatierung eines NOx-Speicherkatalysators

In a method for operating a hybrid vehicle with a combustion engine coupled to an electric motor having at least one inlet and one outlet valve per cylinder, a variable valve control, and a fuel injection device, with a first partial power, from the overall drive power provided to the vehicle, it is provided that upon request a cylinder that can be switched off is deactivated and filled with fresh gas, and upon request for activating the cylinder in the temporally next suction and/or compression phase of the cylinder a predetermined amount of fuel and an ignition of the mixture occurs by no later than the end of the compression phase and/or that in order to adjust the momentum during the activation of a cylinder that had been switched off a multiple injection of fuel occurs, preferably a dual injection, in a homogenous split mode of operation.

Method for operating a hybrid vehicle and hybrid vehicle with a multi-cylinder internal combustion engine coupled to an electric motor

By measuring the exhaust gas temperature with temperature sensors located immediately before and after an NOx reservoir in the exhaust gas line of an internal combustion engine, and by suitable control of rich-lean operation, an NOx reservoir catalyst can be heated above the desulfurization temperature. Immediately after desulfurization normal operation is restored in the case of a Diesel engine, whereas, in the case of an Otto engine, λ=1 operation is carried out briefly before returning to normal rich-lean operation.

Method and arrangement for desulfurization of NOx reservoir catalysts

Die Erfindung betrifft ein Verfahren zur Stickoxidreduzierung im Abgas einer Brennkraftmaschine,
bei dem der Beladungszustand eines NO X -Speicherkatalysators ermittelt wird und
bei Uberschreitung eines ersten Schwellwertes gepruft wird, ob die Betriebsparameter eine
Regeneration erlauben und gegebenenfalls Einleitung der Regeneration, wenn die Fahrsituation
dies erlaubt, andernfalls Uberprufung der Betriebsparameter und der Fahrsituation
bis eine Regeneration moglich ist oder ein zweiter Schwellwert fur den Beladungszustand
des NO X -Speicherkatalysators uberschritten wird, worauf dann Masnahmen zur Anderung
der Betriebsparameter eingeleitet werden, um eine Regeneration zu ermoglichen, falls die
Fahrsituation dies erlaubt, um dann die Regeneration so lange durchzufuhren bis entweder
der erste Schwellwert des Beladungszustandes unterschritten wird oder die Fahrsituation
eine Unterbrechung der Regeneration erfordert.

Ekkehard Pott

Papers

No exhaust emission control method and arrangement

Verfahren zur De-Sulfatierung eines NOx-Speicherkatalysators

Method for operating a hybrid vehicle and hybrid vehicle with a multi-cylinder internal combustion engine coupled to an electric motor

Method and arrangement for desulfurization of NOx reservoir catalysts

Verfahren zur Stickoxidreduzierung im Abgas einer Brennkraftmaschine