Systems and methods for controlling exhaust gas emissions of a multiple SCR aftertreatment system

An exhaust aftertreatment system, comprising

• a first selective catalyst reduction (SCR) system coupled to a first reductant doser;
• a second SCR system coupled to a second reductant doser, wherein the second SCR system and the second reductant doser are disposed downstream from the first SCR system and the first reductant doser;
• and
• a controller coupled to the first and second SCR systems and the first and second reductant dosers, wherein the controller is configured to:
• receive data indicative of a temperature of the first SCR system;
• receive data indicative of a temperature of the second SCR system;
• receive data indicative of a reductant storage of the second SCR system;
• in response to the temperature of the first SCR system and the second SCR system being below a predefined temperature threshold, cease dosing from the first and second reductant dosers;
• in response to the temperature of the first SCR system being at or above the predefined temperature threshold and the temperature of the second SCR system being below the predefined temperature threshold, command dosing from the first reductant doser and cease dosing from the second reductant doser;
• in response to the temperature of the first SCR system being at or above the predefined temperature threshold and the temperature of the second SCR system being at or above the predefined temperature threshold, command relatively more dosing from the second reductant doser than from the first reductant doser or relatively less dosing from the first reductant doser than from the second reductant doser;
• and
• command, during an activation of the first reductant doser, an increase or a decrease in an amount of reductant dosing from the first reductant doser upstream of the first SCR system to dose the first SCR system, wherein the amount of reductant dosing from the first reductant doser to increase or decrease is determined based on the temperature of the second SCR system and the reductant storage of the second SCR system.

An apparatus, comprising:

• one or more processors;
• and
• one or more memory devices coupled to the one or more processors, the one or more memory devices storing instructions that, when executed by the one or more processors, cause the one or more processors to:
• receive data indicative of a first Selective Catalytic Reduction (SCR) catalyst and a second SCR catalyst of an aftertreatment system, wherein the data includes a first temperature regarding the first SCR catalyst, a second temperature regarding the second SCR catalyst, and a reductant storage of the second SCR catalyst, wherein a first reductant doser is associated with the first SCR catalyst and a second reductant doser is associated with the second SCR catalyst;
• determine a reductant dosing strategy based on a comparison of the first temperature and the second temperature to at least one respective a first temperature threshold and a second temperature threshold, respectively;
• command, responsive to the first temperature being at or above the first temperature threshold and the second temperature being at or above the second temperature threshold, relatively more dosing from the second reductant doser than from the first reductant doser or relatively less dosing from the first reductant doser than from the second reductant doser;
• determine to increase or decrease an amount of reductant dosing during an activation of the first reductant doser associated with the first SCR catalyst based on at least one of the second temperature or the reductant storage associated with the second SCR catalyst;
• and
• command, based on the determination to increase or decrease the amount of reductant dosing according to the second temperature and the reductant storage associated with the second SCR catalyst, an increase or a decrease in the amount of reductant dosing from the first reductant doser during the activation of the first reductant doser.