Technical solutions are described for an emissions control system for a motor vehicle including an internal combustion engine. An example emissions control system for treating exhaust gas in a motor vehicle including an internal combustion engine. For example, the emissions control system includes a selective catalytic reduction (SCR) device, an NOx sensor, and a controller that is configured to detect a NH3 slip of the SCR device. The controller detects the NH3 slip by modulating an engine out NOx from an engine, demodulating the engine out NOx from the engine to original state, and measuring NOx upstream and downstream from the SCR device after the modulation. Further, the controller determines the NH3 slip by comparing gradients in the NOx measurement with one or more predetermined thresholds.

Technical solutions are described for an emissions control system for controlling a selective catalytic reduction (SCR) device of an exhaust system of an internal combustion engine. An example computer-implemented method includes governing a reductant dosing in the SCR device. For example, governing the dosing includes computing a reductant dosing rate based on a chemical model of the SCR device. Further, the governing includes determining a temperature modulation factor based on inlet temperature of exhaust gas input for the SCR. The method further includes adjusting the reductant dosing rate by scaling the reductant dosing rate by the temperature modulation factor. The method further includes causing an amount of reductant to be injected into an SCR catalyst according to the adjusted reductant dosing rate.

An apparatus includes a pump, a delivery mechanism in fluid communication with the pump, and a controller communicatively coupled to the pump and the delivery mechanism. The controller is structured to interpret, via a pump diagnostic circuit, first and second pump parameters indicative of first and second pump rates, interpret, via a dosing diagnostic circuit, first and second dosing parameters indicative of at least one of (i) first and second reductant flows or (ii) first and second injector characteristics, determine, via a delivery diagnostic circuit, a delivery status based, at least in part, on the interpretation of the first and second pump parameters and the first and second dosing parameters, and generate, via the delivery diagnostic circuit, a status command indicative at least one of an under-restricted delivery mechanism or an over-restricted delivery mechanism in response to the determination of the delivery status.

A diesel exhaust fluid (DEF) delivery system and method for operating same. The method includes determining, by an electronic processor, an operating pressure, and receiving, from a pressure sensor of the DEF delivery system, a system pressure. The method further includes determining, by the processor, a dosing request and a pressure disturbance based on the dosing request. The method further includes determining, by the processor, a control request based on the system pressure and the operating pressure, and a feed forward control value based on the pressure disturbance. The method further includes generating, by the processor, an adjusted control request based on the control request based and the feed forward control value. The method further includes controlling, by the processor, a dosing valve of the DEF delivery system based on the dosing request, and a pressure adjustment component of the DEF delivery system based on the adjusted control request.

A method for asynchronously delivering a reductant to a first selective catalytic reduction system and a second selective catalytic reduction system of an aftertreatment system via a reductant insertion assembly, the reductant insertion assembly comprising a first injector fluidly coupled to the first selective catalytic reduction system and a second injector fluidly coupled to the second selective catalytic reduction system, the method including: activating the first injector; maintaining the first injector activated for a first delivery time, thereby inserting a first amount of reductant into the first selective catalytic reduction system; deactivating the first injector; activating the second injector; and maintaining the second injector activated for a second delivery time, thereby inserting a second amount of reductant into the second selective catalytic reduction system.

In a selective catalytic reductant dosing system including a reductant injector adapted to inject liquid reductant into an exhaust line, a method of analyzing flow of reductant through the injector includes determining a measure of the temperature of the injector prior to activation of the injector. The method also includes activating the injector and determining a measure of the temperature of the injector subsequent to activation of the injector. The method also includes analyzing the flow of reductant through the injector consequential to the activation by analyzing changes in the measure of temperature of the injector prior to activation and the measure of temperature of the injector subsequent to activation.

A urea SCR system includes a tank that stores urea water, an injector that injects urea water to exhaust gas, a connection passage that connects the tank and the injector, an electric pump that is arranged at the connection passage and delivers urea water from the tank toward the injector or from the injector toward the tank, and a control device that controls the electric pump and the injector. The control device executes a suction-back operation for driving the electric pump so that urea water contained in the injector is suctioned back to the tank. Further, the control device determines whether or not the injector is stuck closed.

A method for operating a conveying device for an aqueous urea solution in a motor vehicle, having a pump for conveying the aqueous urea solution, wherein the aqueous urea solution is conveyed from a tank along a pressure line to an injector, wherein the injector is arranged on an exhaust gas line and is designed to inject the aqueous urea solution into the exhaust gas line. The conveying speed of the pump is controlled depending on the opening operations and closing operations of the injector and/or the pressure conditions resulting therefrom in the conveying section between the pump and the injector.

An aftertreatment system includes an inlet exhaust section, an outlet exhaust section, a first aftertreatment component, a first dosing module, and a second dosing module. The inlet exhaust section receives exhaust. The outlet exhaust section is in fluid communication with the inlet exhaust section. The first aftertreatment component receives the exhaust from the inlet exhaust section, treats the exhaust, and provides the exhaust to the outlet exhaust section. The first dosing module is positioned along the inlet exhaust section. The first dosing module is structured to selectively dose the exhaust with reductant. The second dosing module is positioned along the outlet exhaust section. The second dosing module is structured to selectively dose the exhaust with the reductant.

Systems and methods for diagnosing an exhaust aftertreatment system are provided. A method includes: receiving, by a controller and for each sensor of a plurality of sensors, one or more respective degradation level indicators indicative of one or more failure levels of the sensor, each of the one or more degradation level indicators determined using a corresponding performance parameter; receiving, by the controller and for each sensor of the plurality of sensors, one or more diagnosis threshold values; determining, by the controller, a multipoint diagnosis threshold value using the one or more diagnosis threshold values associated with the plurality of sensors; detecting, by the controller, an operational state of the aftertreatment system by comparing a performance value of the aftertreatment system to the multipoint diagnosis threshold value; and causing, by the controller, an indication of the operational state of the aftertreatment system to be displayed on a display device.