Methods for controlling and detecting catalyst poisoning of selective catalytic reduction devices

    公开(公告)号:US10215072B2

    公开(公告)日:2019-02-26

    申请号:US15467312

    申请日:2017-03-23

    Abstract: Method for controlling and detecting ammonium nitrate and/or ammonium nitrite poisoning within selective catalytic reduction (SCR) devices and systems incorporating the same are provided. Methods can include detecting a SCR inlet exhaust gas NO2:NOx ratio above a poisoning NOx flux threshold, detecting a SCR temperature below a poisoning temperature threshold, and determining SCR catalyst poisoning. Methods can further include performing a SCR catalyst cleaning strategy, wherein the SCR cleaning strategy comprises heating the SCR catalyst composition to a temperature above the poisoning temperature threshold. Cleaning strategies can including utilizing a heater, implementing a post-injection, after-injection, and/or auxiliary injection engine strategy wherein the engine is configured to supply exhaust gas to the SCR. Methods can further include arresting reductant dosing, identifying an opportunistic regeneration opportunity, and/or inhibiting performance of an appurtenant oxidation catalyst subsequent to determining SCR catalyst poisoning. The SCR catalyst composition can comprise iron and/or copper.

    Method for diagnosing and controlling ammonia oxidation in selective catalytic reduction devices

    公开(公告)号:US10690079B2

    公开(公告)日:2020-06-23

    申请号:US15838860

    申请日:2017-12-12

    Abstract: An emissions control system for treating exhaust gas containing NOx emissions from an internal combustion engine comprises a selective catalytic reduction (SCR) device that stores reductant that reacts with the NOx emissions, a reductant supply system configured to inject the reductant according to a reductant storage model; NOx module(s) configured to generate an NOx concentration signal indicating an NOx concentration, temperature module(s) configured to generate a temperature signal indicating an SCR temperature of the SCR device, and a control module operably connected to the reductant supply system, the NOx module, and the temperature module. The control module is configured to determine an amount of the reductant that is parasitically oxidized based on the NOx concentration signal and the temperature signal, and to determine a correction factor based on the amount of parasitically oxidized reductant to modify the reductant storage model.

    Method For Diagnosing And Controlling Ammonia Oxidation In Selective Catalytic Reduction Devices

    公开(公告)号:US20190178187A1

    公开(公告)日:2019-06-13

    申请号:US15838860

    申请日:2017-12-12

    Abstract: An emissions control system for treating exhaust gas containing NOx emissions from an internal combustion engine comprises a selective catalytic reduction (SCR) device that stores reductant that reacts with the NOx emissions, a reductant supply system configured to inject the reductant according to a reductant storage model; NOx module(s) configured to generate an NOx concentration signal indicating an NOx concentration, temperature module(s) configured to generate a temperature signal indicating an SCR temperature of the SCR device, and a control module operably connected to the reductant supply system, the NOx module, and the temperature module. The control module is configured to determine an amount of the reductant that is parasitically oxidized based on the NOx concentration signal and the temperature signal, and to determine a correction factor based on the amount of parasitically oxidized reductant to modify the reductant storage model.

    Exhaust treatment system including ammonia storage control system

    公开(公告)号:US10247076B2

    公开(公告)日:2019-04-02

    申请号:US15481941

    申请日:2017-04-07

    Abstract: A vehicle includes an engine that combusts an air/fuel mixture to produce an exhaust gas stream containing oxides of nitrogen (NOx). A dosing system injects an amount of ammonia (NH3) into the exhaust gas stream based on an initial NH3 injection set point value. A selective catalyst reduction (SCR) device absorbs an amount of the NH3 contained in the exhaust gas stream and reduces an amount of NOx. An electronic hardware controller predicts an NH3 slip condition during which a portion the absorbed NH3 will slip from the SCR device, and modifies the initial NH3 injection set point value based on the predicted NH3 slip condition. The controller further generates a modified NH3 injection set point signal indicating an adjusted amount of the NH3 to inject during the predicted NH3 slip condition. The dosing system adjusts the amount of injected NH3 based on the modified NH3 injection set point signal.

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