Method for operating an exhaust aftertreatment system having an SCR catalyst
AssigneeMTU Friedrichshafen GmbH
InventorsJens Niemeyer, Tim Späder
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Abstract
A method for operating a system having an internal combustion engine and an exhaust aftertreatment system having an SCR catalyst, wherein the internal combustion engine is controlled on the basis of at least one process parameter that influences a nitrogen oxide raw emission, wherein aging detection is performed for the SCR catalyst, wherein in a first operating mode of the internal combustion engine, if aging of the SCR catalyst is detected, the at least one process parameter is changed in the direction of a reduced nitrogen oxide raw emission, wherein the internal combustion engine is controlled on the basis of the changed at least one process parameter.
Claims6
A method of operating a system having an internal combustion engine and an exhaust gas aftertreatment system comprising an SCR catalyst, the method comprising the steps of:
- actuating the internal combustion engine based on at least one process parameter that affects raw nitrogen oxide emission;
- conducting aging recognition for the SCR catalyst;
- in a first mode of operation of the internal combustion engine, changing the at least one process parameter in a direction of reduced raw nitrogen oxide emission when aging of the SCR catalyst is recognized;
- and
- actuating the internal combustion engine based on the changed at least one process parameter, wherein
- when aging is recognized, the at least one process parameter is changed in the direction of a reduction in the raw nitrogen oxide emission when the raw nitrogen oxide emission is greater than a predetermined minimal raw nitrogen oxide emission, wherein
- the change in the process parameter is ended when
- a) the raw nitrogen oxide emission is greater than the predetermined minimal raw nitrogen oxide emission and no aging is detected any longer, or when
- b) the raw nitrogen oxide emission reaches or goes below the level of the minimal raw nitrogen oxide emission.
An exhaust gas aftertreatment system for an internal combustion engine, comprising:
- an SCR catalyst;
- and
- a control unit including:
- a closed-loop control configured to actuate the internal combustion engine based on at least one process parameter that affects raw nitrogen oxide emission;
- and an aging recognition configured to conduct recognition of aging for the SCR catalyst, and in a first mode of operation of the internal combustion engine, when aging is recognized, to change the at least one process parameter in a direction of reduced raw nitrogen oxide emission, wherein
- the closed-loop control is configured to actuate the internal combustion engine based on the at least one changed process parameter, wherein
- when aging is recognized, the at least one process parameter is changed in the direction of a reduction in the raw nitrogen oxide emission when the raw nitrogen oxide emission is greater than a predetermined minimal raw nitrogen oxide emission, wherein
- the change in the process parameter is ended when
- a) the raw nitrogen oxide emission is greater than the predetermined minimal raw nitrogen oxide emission and no aging is detected any longer, or when
- b) the raw nitrogen oxide emission reaches or goes below the level of the minimal raw nitrogen oxide emission.
Dependencies are inferred from the claim text.