Abstract:
The invention relates to an exhaust gas cleaning system for at least removing nitrogen oxides contained in the exhaust gas of a combustion source. The inventive exhaust gas cleaning system comprises an ammonia producing catalytic converter (5) for producing ammonia by using constituents of at least a portion of the exhaust gas emitted by the combustion source (1) during operating phases in which ammonia is produced. The exhaust gas cleaning system also comprises a nitrogen oxide reduction catalytic converter (4) which is arranged downstream from the ammonia producing catalytic converter and which is provided for reducing nitrogen oxides contained in the emitted exhaust gas of the combustion source by using the produced ammonia as a reducing agent. According to the invention, a plasma generator (6) is connected upstream from said ammonia producing catalytic converter (5) and serves to produce, using plasma technology, reactive particles which consist of the constituents of the exhaust gas fed to the ammonia producing catalytic converter and which promote the ammonia producing reaction during operating phases in which ammonia is produced. This ensures an adequate production of ammonia also in the case of relatively low exhaust gas temperatures. The invention also relates to the use of said exhaust gas cleaning system, for example, for cleaning the waste gas of motor vehicle internal combustion engines which are mainly operated with a lean mixture.
Abstract:
An engine (1) has first and second cylinder groups (1a and 1b). The first cylinder group (1a) is connected to a three way (TW) catalyst (8a). The second group (1b) and the TW catalyst (8a) are connected, via an interconnecting duct (13) to an NH3 adsorbing and oxidizing (NH3-AO) catalyst (14a). The first group (1a) performs the rich operation, and the second group (1b) performs the lean operation. In the TW catalyst (8a), NOx exhausted from the first group (1a) is converted to NH3, and the NH3 reduces the NOx exhausted from the second group (1b) in the NH3-AO catalyst (14a). An NOx occluding and reducing (NOx-OR) catalyst (11a) is arranged in the exhaust passage between the second group (1b) and the interconnecting duct (13), to thereby suppress the NOx amount flowing into the NH3-AO catalyst (14a).
Abstract:
A three-way catalyst (8a) is connected to a first group of cylinders (1a) whereby exhaust gas discharged from the first group of cylinders (1a) and passing through the three-way catalyst (8a) and exhaust gas discharged from a second group of cylinders (1b) are conducted to an exhaust gas purifying catalyst (14). The second group of cylinders (1b) are operated with a lean gas. The first group of cylinders (1a) are operated with a rich gas, so that NH3 is generated from NOx in the exhaust gas of the first group of cylinders (1a) by means of the three-way catalyst (8a). The exhaust gas purifying catalyst (14) causes NH3 from the three-way catalyst (8a) to purify NOx in the exhaust gas of the second group of cylinders (1b). An amount of HC flowing into the three-way catalyst (8a) is found, and when the amount of HC exceeds a set amount, the first group of cylinders (1a) is temporarily operated with a lean gas, thereby maintaining a favorable catalytic activity of the three-way catalyst (8a).
Abstract:
A system comprises an engine including a plurality of cylinders. A first intake throttle is positioned upstream of a first set of cylinders of the plurality of cylinders. The first intake throttle provides air at a first flow rate to the first set of cylinders so as to produce a lean air/fuel mixture in the first set of cylinders. A second intake throttle is positioned upstream of a second set of cylinders included in the plurality of cylinders and in parallel of the first intake throttle. The second intake throttle provides air at a second flow rate to the second set of cylinders so as to produce a rich air/fuel mixture in the second set of cylinders.
Abstract:
Described are exhaust gas treatment systems for treatment of a gasoline engine exhaust gas stream. The exhaust gas treatment systems comprise an ammonia generating catalyst and an ammonia selective catalytic reduction (SCR) catalyst downstream of the ammonia generating catalyst. The ammonia generating catalyst comprises a NO x storage component, a refractory metal oxide support, a platinum component, and a palladium component. The ammonia generating catalyst is substantially free of ceria. The platinum and palladium components are present in a platinum to palladium ratio of greater than about 1 to 1.
Abstract:
A system and method for utilizing fuel as an on-board reductant for selective catalytic reduction of NOx is provided and includes a controller for controlling an engine to produce a lean first exhaust stream and a rich second exhaust stream that are received in respective first and second passageways of a dual path aftertreatment system. The rich second exhaust stream reacts with NOx stored in a NOx storage and reduction catalyst of the second passageway to regenerate this catalyst and generate ammonia. The first exhaust stream and the second exhaust stream having the generated ammonia are combined in a downstream common passageway to form a combined lean exhaust gas stream where the ammonia carried therein is stored or used by an SCR catalyst of the common passageway for NOx reduction. The engine is subsequently controlled to produce a rich first exhaust stream and a lean second exhaust stream.
Abstract:
It is proposed a method for loading or reloading a decomposition unit (2) of a SCR system, the SCR system being mounted on board a vehicle and comprising a filler pipe (7) in communication with the decomposition unit. The method is such that at least one capsule (3) containing at least one protein component adapted to decompose ammonia precursor is introduced through the filler pipe and is then guided through the filler pipe towards the decomposition unit.
Abstract:
Die Erfindung betrifft ein Verfahren zum Betreiben eines Abgasreinigungssystems (1) zum Reinigen eines Abgases einer Brennkraftmaschine, wobei in einem Diagnosebetrieb in sich unmittelbar aneinander anschließenden Betriebsphasen der Brennkraftmaschine mit Magerbetriebsmodus und mit Fettbetriebsmodus durch Auswertung der Signale eines ersten und eines zweiten Abgassensors (S1, S2) die Ammoniak- Speicherfähigkeit eines Ammoniak-SCR-Katalysators (7), die Sauerstoff-Speicherfähigkeit eines Stickoxid-Speicherkatalysators (8) und optional die Stickoxid-Speicherfähigkeit des Stickoxid- Speicherkatalysators (8) ermittelt werden.
Abstract:
The present invention is concerned with an exhaust treatment system and a process for the abatement of noxious pollutants being emitted from a gasoline vehicle. In particular, the present invention is directed to an exhaust system which comprises one or more three-way catalysts (TWC) in a close-coupled (cc) position and an HC-trap / SCR-device in an underfloor (uf) region of the car.