A method is presented for estimating an amount of ammonia stored in a urea-based SCR catalyst based on a dynamic model of the catalyst. The model takes into account chemical and physical properties of the catalyst, such as catalyst volume, the number of available ammonia storage cites, adsorption and desorption dynamics, as well as poisoning, thermal aging, and different catalyst operating temperatures, and generates the estimate based on a measured or estimated amount of NOx in an exhaust gas mixture upstream of the catalyst, an amount of reductant injected into the catalyst to facilitate NOx reduction, and on a measured value of NOx in an exhaust gas mixture downstream of the catalyst. The estimated ammonia storage amount is then used to control the amount of reductant injected into the catalyst to maintain desired ammonia storage amount such that maximum NOx conversion efficiency coupled with minimum ammonia slip are achieved.

Exhaust gas aftertreatment systems

An internal combustion engine wherein an HC treatment catalyst (12) having the function of adsorbing the HC in the exhaust gas is arranged upstream of the NOx selective reducing catalyst (14), an urea aqueous solution fed from the reducing agent feed valve (15) is arranged upstream of the HC treatment catalyst (12), urea, and NOx contained in the exhaust gas, and HC adsorbed on the HC treatment catalyst 12 are reacted with each other to form intermediate products having cyano groups, oximes, and amino groups, and these intermediate products are sent to the NOx selective reducing catalyst (14).

Exhaust purification device of internal combustion engine

We provide a system for issuing identification documents to a plurality of individuals, comprising a first database, a first server, and a workstation. The first database stores a plurality of digitized images, each digitized image comprising a biometric image of an individual seeking an identification document. The first server is in operable communication with the first database and is programmed to send, at a predetermined time, one or more digitized images from the first database to a biometric recognition system, the biometric recognition system in operable communication with a second database, the second database containing biometric templates associated with individuals whose images have been previously captured, and to receive from the biometric recognition system, for each digitized image sent, an indicator, based on the biometric searching of the second database, as to whether the second database contains any images of individuals who may at least partially resemble the digitized image that was sent. The a workstation is in operable communication with the first server and is configured to permit a user to review the indicator and to make a determination as to whether the individual is authorized to be issued an identification document or to keep an identification document in the individual's possession.

Systems and methods for managing and detecting fraud in image databases used with identification documents

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

An internal combustion engine includes an exhaust-gas aftertreatment device, and an operating method is for operating the internal combustion engine. The internal combustion engine is operable with a lean mixture and a rich mixture, the internal combustion engine having an exhaust-gas aftertreatment device, which includes a nitrogen oxide storage catalytic converter and a particle filter. When lean exhaust gas flows through the nitrogen oxide storage catalytic converter, it removes nitrogen oxides from the exhaust gas by storing them, and, when reducing exhaust gas flows through the nitrogen oxide storage catalytic converter, it produces ammonia through reduction of stored and/or supplied nitrogen oxides and releases it to the exhaust gas. Downstream from the nitrogen oxide storage catalytic converter, the exhaust-gas aftertreatment device includes a SCR catalytic converter, which reduces nitrogen oxides contained in the exhaust gas, using ammonia produced by the nitrogen oxide storage catalytic converter.

Exhaust-gas aftertreatment device with nitrogen oxide storage catalytic converter, and operating method therefor

A method and apparatus for periodically desulphating a nitrogen oxide or sulphur oxide storage vessel of an exhaust emission control system of a multi-cylinder internal combustion engine, in which an engine exhaust emission containing reducing agent and oxygen is fed to the nitrogen oxide or sulphur oxide storage vessel by setting a rich fuel/air ratio for a first subset of the engine cylinders and a fuel/air ratio which is, in comparison, leaner for the other cylinders. The distance between the fuel/air ratio for the first subset of the engine cylinders and that for the second subset of the engine cylinders is set higher in an initial storage vessel heating-up phase than in the subsequent desulphation mode, and/or control errors of the entire fuel/air ratio are eliminated by a predefinable set point value by modifying the fuel/air ratio either of just the first subset or just the second subset of the engine cylinders. Used, for example, in motor vehicles.

Method and device for periodically desulphating a nitrogen oxide or sulphur oxide storage vessel with rich/lean engine cylinder distribution

At a switching point (Tu), the end of the fuel injection (T) is altered for the selected power stroke. During the limited continuous drive phase, the fuel injected mixture is matched to the intake air mass by adjusting the injection time (T). The timing of the ignition point (22) is varied in proportion to the change in injection time by retarding the spark timing.

Method of controlling fuel injection for motor vehicle internal combustion engine

In a method for operating an emission control system having nitrogen oxide storage, for cleaning up a nitrogen oxide-containing, sulfur-contaminated exhaust gas from combustion equipment, from time to time desulfating phases are performed for releasing sulfur intercalated in the nitrogen oxide storage. Two desulfating modes are provided, namely, a main desulfating mode for substantially completely desulfating the nitrogen oxide storage and a partial desulfating mode for partially desulfating same, a lower nitrogen oxide storage minimum temperature and a shorter desulfating target duration being predefined for the partial desulfating processes than for the main desulfating processes. The method may be used, for example, in emission control systems of predominantly lean-combustion operated Otto engines of motor vehicles.

Andreas Hertzberg

Papers

Exhaust Gas Aftertreatment Installation and Method

Exhaust-gas aftertreatment device with nitrogen oxide storage catalytic converter, and operating method therefor

Method and device for periodically desulphating a nitrogen oxide or sulphur oxide storage vessel with rich/lean engine cylinder distribution

Method of controlling fuel injection for motor vehicle internal combustion engine

Method for operating an emission control system having nitrogen oxide storage