A method for metering a reactant into an exhaust gas path of an internal combustion engine, wherein the reactant is introduced into an area of the exhaust gas path in which pressure surges in the exhaust gas stream, generated by a charge exchange of the internal combustion engine, contribute to breakdown of droplets of the reactant, wherein a metering device for metering the reactant is activated at a variable metering frequency, depending on an operating point of the internal combustion engine.

An exhaust treatment catalyst (13) arranged in an engine exhaust passage and a heat and hydrogen generation device (50) are provided. The amount of fuel fed to the heat and hydrogen generation device (50), which is required for making the temperature of the exhaust treatment catalyst (13) rise by exactly a predetermined temperature rise by heat and hydrogen fed from the heat and hydrogen generation device (50) when the exhaust treatment catalyst (13) is not poisoned and does not thermally deteriorate, is calculated based on the amount of exhaust gas. When fuel of the reference feed fuel amount corresponding to the amount of exhaust gas is fed to the heat and hydrogen generation device (50) and the temperature rise of the exhaust treatment catalyst (13) fails to reach the predetermined temperature rise, the treatment for restoration from poisoning of the exhaust treatment catalyst (13) is performed.

In one aspect, a system for controlling the temperature of an exhaust reductant used within an exhaust treatment system of a work vehicle may generally include a tank having a plurality of walls defining an enclosed volume for containing the exhaust reductant. The tank may also include a threaded port defined through a first wall of the plurality of walls. The system may also include an electric heating device having a mounting portion and a heating element. The mounting portion may be configured to be screwed into the threaded port to couple to the electric heating device to the tank. In addition, the system may include a controller communicatively coupled to the electric heating device that is configured to control the operation of the electric heating device based on a temperature associated with the tank.

Systems and methods are provided for controlling a selective catalyst reduction (SCR) system having a SCR reactor. A reductant slip set point indicative of a target slip is received as a control variable is to be utilized for maintaining an amount of a NO.sub.x composition included in a combustion gas below a selected limit. A signal transmitted by a sensor is received, and is indicative of the reductant slip downstream of the SCR reactor. An amount of a NO.sub.x reductant to be introduced to the SCR reactor is determined based, at least in part, on a relationship between the target reductant slip and the reductant slip downstream of the SCR reactor indicated by the signal. A control signal is transmitted to cause introduction of the amount of the NO.sub.x reductant to the SCR reactor to maintain the amount of the NO.sub.x composition in the combustion gas below the selected limit.

A controller for an exhaust aftertreatment system receives a pressure signal from a pressure sensor. The pressure sensor generates the pressure signal based on a pressure of treatment fluid in a downstream dosing module. The controller further determines a pressure measurement based on the pressure signal, determines a first injection amount based on the pressure measurement, and causes an upstream injector of an upstream dosing module to inject the treatment fluid according to the first injection amount. The controller further determines a second injection amount based on the pressure measurement and a resistance of a variable resistor and causes a downstream injector of a downstream dosing module to inject the treatment fluid according to the second injection amount.