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

The invention relates to a method for controlling a temperature of a catalyst system (14, 16) located in an exhaust duct (12) of an internal combustion engine (10) in a motor vehicle. Said system comprises at least one primary catalyst (16), in particular an NOx storage catalyst and optionally one or more pre-catalysts (14). According to the invention, at one point during operation, at which the torque desired by the driver is less than an overrun torque of the vehicle (overrun phase τs), an overrun shut-off can be suppressed by supplying the internal combustion engine (10) with an air-fuel ratio (λ) that is less than or equal to 1.1.

Method for controlling a working mode of an internal combustion engine

Eine Schwefelfalle und ein Verfahren zur Regeneration einer Schwefelfalle wird beschrieben,
wobei die Schwefelfalle einem NOx-Speicher vorgelagert ist. Die Schwefelfalle umfast einen
konzentrisch axial in der Schwefelfalle angeordneten Bypass, der mittels einer Klappe offen- und
verschliesbar ist. Nach dem Umschalten der Motorbetriebsbedingungen von mager auf
fett nach der Detektion der Regenerationsnotwendigkeit der Schwefelfalle wird die
Schwefelfalle elektrisch auf oberhalb einer De-Sulfatierungs-Mindesttemperatur aufgeheizt.
Dabei ist zu Beginn der Aufheizung der Bypass der Schwefelfalle geoffnet. Nach
Verstreichen einer vorbestimmten Mindestzeit wird die Heizung der Schwefelfalle
abgeschaltet und der Motor wieder auf Magerbetrieb umgestellt, nachdem ein weiterer
Zeitlauf verstrichen ist, um sicherzustellen, das die Sulfatsaule sich aus dem NOx-Speicher
hinausbewegt hat. In dem Fettbetrieb der Motors wird gleichzeitig eine Regeneration des
NOx-Speichers bewirkt. Bei Schwefelfallen, bei denen eine thermische De-Sulfatierung
unterhalb einer De-Sulfatierungsmindesttemperatur sicher ausgeschlossen werden kann,
kann die Schwefelfalle bereits elektrisch geheizt werden, bevor ein Motorbetrieb mit λ ≤ 1
eingestellt wird.

Verfahren und Vorrichtung zur Regeneration einer Schwefelfalle

Exhaust flow rate of through the purification system (12) is measured or modeled. Actual temperature is measured or modeled in selected regions of the system (12), and compared with a desired temperature value, forming a temperature difference. As a function of this and the flow rate, a desired energy input into the system is determined. Parameters characterizing the heating stage are so set and imposed, that the required energy input is supplied, at least approximately. The required energy input is controlled as a function of exhaust gas composition. An independent claim is made for corresponding equipment.

Control of hot regeneration stage in engine exhaust purification system, determines temperatures, flow rate and composition, to control total energy input

An exhaust gas converter arrangement includes a common catalyst support with a precatalyst section and a main catalyst section of larger size downstream in the direction of exhaust flow. The common support is made of alternate corrugated and flat sheet metal members wound into cylindrical shape. Between the precatalyst section and the main catalyst section, the support has an intermediate region in which the sheet metal members are formed with apertures to minimize heat conduction between the catalyst sections.

Exhaust gas converter arrangement

Die Erfindung betrifft ein Verfahren und eine Vorrichtung zur Steuerung eines Betriebes eines Mehrzylindermotors fur Kraftfahrzeuge mit einer mehrflutigen Abgasreinigungsanlage. Es ist vorgesehen, das die Abgasreinigungsanlage aus mindestens zwei, einer Anzahl von Zylindern (Bank) zugeordneten Abgasstrangen mit jeweils zumindest einem NOx-Speicherkatalysator und einem Gassensor besteht, und das bei dem Verfahren und der Vorrichtung die Betriebsmodi jeder Bank in Abhangigkeit von einem Koordinationsmodus sowie einem Katalysatorzustand und/oder einer Schadstoffemission in allen Abgasstrangen eingestellt werden (koordinierte Steuerung).

Ekkehard Pott

Papers

Method for controlling a working mode of an internal combustion engine

Verfahren und Vorrichtung zur Regeneration einer Schwefelfalle

Control of hot regeneration stage in engine exhaust purification system, determines temperatures, flow rate and composition, to control total energy input

Exhaust gas converter arrangement

Vorrichtung und verfahren zur steuerung eines betriebes eines mehrzylindermotors für kraftfahrzeuge mit einer mehrflutigen abgasreinigungsanlage