Disclosed is a process for the dynamic monitoring of the flow rate of liquid additive consumed by a liquid-additive injector of an exhaust gas treatment system of a motor vehicle. The measurement of the pressure of the liquid makes it possible firstly to deduce the flow rate circulating through the orifice and secondly, by knowing the operating characteristic of the pump, to determine the flow rate of liquid additive actually delivered to the system for treating polluting gases. The process also provides a phase of characterizing the pump, including commanding the closure of the injector, measuring at least two pressure values for two different operating speeds of the pump, and updating the pump operating characteristics table on the basis of the pressure values measured.

A selective catalytic reduction system control system (10) and method of its use include an ammonia (“NH.sub.3”) slip sensor (13) located within an interior space (27) of an exhaust stack (15) of a selective catalytic reactor (31), toward an inlet end (25) of the stack (15); a housing (17) located within the interior space of the exhaust stack; the housing including face panels 19; a nitrogen oxides (“NOx”) sensor (11) contained within an interior space (29) defined by the face panels of the housing, at least two of the face panels (19.sub.I, 19.sub.O) containing an oxidation catalyst; and a dosing controller (59) in communication with the NH.sub.3 and NOx sensors, the dosing controller including a microprocessor with dosing logic embedded thereon. The housing with oxidation catalyst acts as a linear box, isolating the NOx sensor from NH.sub.3 slip, linearizing the NOx sensor signal.

A reductant dosing system includes: an injector; a fixed displacement pump in fluid communication with the injector; a reductant source in fluid communication with the fixed displacement pump; a pressure sensor assembly configured to detect a pressure of reductant in the reductant dosing system; and a controller communicatively coupled to the fixed displacement pump and to the pressure sensor assembly, wherein the controller is configured to calculate a flow rate of the fixed displacement pump based on at least a calibration value determined based on data received from the pressure sensor assembly.

Methods and systems for operating an engine with a pump that is driven via the engine are described. In one example, start of opening of an injector that supplies a fluid to an engine exhaust system is timed based on a period of the pump so that the output of the fluid injector may be repeatable in the presence of fluid pressure oscillations that are periodic with pump rotation.

A selective catalytic reduction system control system (10) and method of its use include an ammonia (“NH.sub.3”) slip sensor (13) located within an interior space (27) of an exhaust stack (15) of a selective catalytic reactor (31), toward an inlet end (25) of the stack (15); a housing (17) located within the interior space of the exhaust stack; the housing including face panels 19; a nitrogen oxides (“NOx”) sensor (11) contained within an interior space (29) defined by the face panels of the housing, at least two of the face panels (19.sub.I, 19.sub.O) containing an oxidation catalyst; and a dosing controller (59) in communication with the NH.sub.3 and NOx sensors, the dosing controller including a microprocessor with dosing logic embedded thereon. The housing with oxidation catalyst acts as a linear box, isolating the NOx sensor from NH.sub.3 slip, linearizing the NOx sensor signal.

Embodiments described herein methods can be used in particulate filter regeneration, such as particulate filters used for filtering the exhaust of an engine, e.g., a diesel engine. Systems herein can be configured to dispense combustion gas(es) into housing were a particulate filter is contained and to ignite the combustion gases. Methods for conducting a safety verification process of such systems are disclosed, as well as methods for regenerating the filters. Still other embodiments are described.

Embodiments described herein methods can be used in particulate filter regeneration, such as particulate filters used for filtering the exhaust of an engine, e.g., a diesel engine. Systems herein can be configured to dispense combustion gas(es) into housing were a particulate filter is contained and to ignite the combustion gases. Methods for conducting a safety verification process of such systems are disclosed, as well as methods for regenerating the filters. Still other embodiments are described.

In an assembly and methods for NO.sub.x reductant dosing with variable spray angle nozzle, according to various embodiments, a reductant dosage is calculated. A reductant delivery region in an exhaust stream area of an aftertreatment system and an actuation period may be specified. Based at least on the reductant delivery region and the actuation period, the reductant insertion assembly may be placed in a state for reductant delivery such that one of a first array of reductant insertion ports and a second array of reductant insertion ports is in an open position. The shape of the variable spray angle nozzle may define different levels. Different arrays of reductant delivery ports may have varying operating characteristics, such as diameter, number of ports, actuation time, and/or reagent delivery angle and may be activated based on reductant flow pressure and/or reductant flow velocity.

A catalyst warming apparatus includes an air blower, a fuel feeder, and an air blowing controller. The air blower is disposed between an engine and a purification catalyst in an exhaust pipe communicating with the engine and is configured to blow air toward the purification catalyst. The fuel feeder is configured to cause the purification catalyst to retain fuel. The air blowing controller is configured to start driving the air blower at a predetermined start timing before a start of the engine.

A system for controlling reductant spray momentum for a target spray distribution includes an exhaust system having an exhaust conduit with exhaust flowing therethrough, a reductant injection system for injecting reductant into the exhaust flowing through the exhaust system based on one or more injection parameters, a reductant supply system for supplying reductant to the reductant injection system based on one or more supply parameters, and a controller. The controller is configured to access current vehicle, engine, exhaust, or reductant condition parameters, determine one or more control parameters based on a control model and the accessed current vehicle, engine, exhaust, or reductant condition parameters, and modify a value of the one or more injection parameters or the one or more supply parameters to control the reductant spray.