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.

A method for controlling a return valve of an exhaust system and to an exhaust system with a control unit which is configured to carry out the method. The method is based on the object of avoiding an overpressure in the line system for urea solution as a result of a reduction in the injection rate. The method includes the steps of determining whether one or more of the following states are present during the operation of the exhaust system: a) an injection rate per unit of time of urea solution of the dosing valve is less than or equal to a predefined injection limit, b) a pressure measured by the pressure sensor in the line system overshoots a predefined first upper pressure limit (P2). The return valve is opened for a first predefined opening duration (Δt1) if states a) and b) are present and at least one of the states has already been present for at least a predefined period of time (Δta). The return valve is closed after the first predefined opening duration (Δt1) has elapsed.

An exhaust aftertreatment system for use with an over-the-road vehicle is disclosed. The exhaust aftertreatment system includes a flash-boil doser mounted to an exhaust conduit and a catalyst coupled to the exhaust conduit. The flash-boil doser configured to inject heated and pressurized reducing agent into an exhaust passageway defined by the exhaust conduit for distribution throughout exhaust gases passed through the exhaust conduit. The catalyst configured to react the reducing agent with the nitrous oxide in the flow of exhaust gases to provide treated exhaust gases with a reduced nitrous oxide amount.

An exhaust aftertreatment system for use with over-the-road vehicle is disclosed. The exhaust aftertreatment system includes a reducing agent mixer with a mixing can and a doser configured to inject heated and pressurized reducing agent into the mixing can for distribution throughout exhaust gases passed through the mixing can.

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.

A reductant insertion system for inserting reductant into an aftertreatment system via a reductant injector comprises a reductant insertion assembly comprising a pump operatively coupled to the reductant injector via a reductant delivery line. A compressed gas source is operatively coupled to the reductant injector and provides a compressed gas to the reductant injector for gas assisted delivery of the reductant. A controller is operatively coupled to the compressed gas source and the reductant insertion assembly and configured to determine whether there is a reductant demand for the reductant. In response to there being no reductant demand, the controller stops the pump and activates the compressed gas source for a predetermined time so as to provide compressed gas to the reductant injector at a pressure sufficient to force reductant contained in the reductant injector upstream towards the reductant insertion assembly via the reductant delivery line while the pump is stopped.

Detecting manipulation of an SCR catalytic converter system of a motor vehicle. A control command (61) for the SCR catalytic converter system, transmitted from a control unit outside the motor vehicle, is received by the motor vehicle. Manipulation is detected (57) if a response (55) of the SCR catalytic converter system to the execution (54) of the control command (61) does not correspond to expectation. Embodiments also relate to monitoring manipulation of the SCR catalytic converter system. Here, a control command (61) for the SCR catalytic converter system is transmitted (41) to the motor vehicle (10) from a control unit (20) outside the motor vehicle.

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.

A reductant insertion assembly comprises a reductant bladder defining a bladder internal volume for holding a reductant. The reductant bladder comprises a bladder inlet and a bladder outlet. A pressure sensor is positioned downstream of the bladder outlet. The pressure sensor is operable to sense a pressure of the reductant downstream of the reductant bladder, and generate a pressure signal indicative of the pressure. A compression mechanism is operably coupled to the reductant bladder. The compression mechanism is configured to selectively exert a compressive force on the reductant bladder so as to expel the reductant therefrom via the bladder outlet. The compression mechanism exerts the compressive force in response to the pressure signal.