A system including a pump fluidly connected to a fluid reservoir, the pump configured to direct diesel exhaust fluid (DEF) from the fluid reservoir to an injector fluidly connected to the pump via a flow line. The system also includes a first pressure sensor configured to determine fluid pressure at a first location in the flow line between the pump and the injector and a second pressure sensor configured to determine fluid pressure at a second location in the flow line between the pump and the injector. The system further includes an air source coupled to the injector via an air flow line, the air source configured to direct air to the injector via the air flow line and a controller communicatively coupled to the first pressure sensor, the second pressure sensor, and the air source, the controller configured to diagnose the system.

A control system is provided to a reductant dosing system for actively maintaining the reductant dosing system ready for use by flushing unused reductant that has crystallized at a return valve of the reductant dosing system. The control system includes a controller that can control a manner of operation of specific system hardware that is present in the reductant dosing system to flush the unused reductant from the return valve that could otherwise cause the return valve to remain a flow-blocking condition as a result of the crystallized reductant.

A leveling nipple for a tank may include a first pipe that includes a curved portion discharging air inside the tank to an outlet pipe when a fluid is supplied to the tank; and a second pipe that discharges air inside the tank to the outlet pipe when the fluid is supplied to the tank and is connected to the curved portion of the first pipe, wherein the second pipe includes a diversion portion that guides the fluid flowing into the second pipe to the first pipe.

An internal combustion engine system includes: an internal combustion engine mounted on a vehicle; a NOx selective reduction catalyst; a reducing agent supply device including a urea water addition valve configured to add urea water into the exhaust gas passage upstream of the NOx selective reduction catalyst, a urea water tank, a urea water flow passage that connects the urea water addition valve and the urea water tank, and a pump configured to supply the urea water addition valve with the urea water from the urea water tank; and a control device. The control device is configured to perform a runoff reduction control that controls at least one of the reducing agent supply device and the internal combustion engine such that the amount of runoff of the urea water from the urea water tank becomes less when the tilt angle of the vehicle is large than when it is small.

A diesel exhaust fluid (DEF) delivery system and method for operating same. The method includes controlling a pump to operate at an idle speed to pressurize a pressure line. The method includes controlling a backflow dosing module (BFDM) valve to open to allow an amount of the DEF to flow into a fluid storage tank through a backflow line. The method includes determining a dosing request, a first dosing actuation request for the first dosing valve and a second dosing actuation request for the second dosing valve based on the dosing request. The method includes, when a sum of the first and second dosing actuation requests is less than 100%, controlling the BFDM valve to close when either of the first and second dosing valves is open; and controlling the BFDM valve to open when the first dosing valve is closed and the second dosing valve is closed.

An exhaust aftertreatment system includes a pump configured to circulate a reagent, an injector configured to deliver the reagent into an exhaust stream, a sensor configured to (i) measure an operating parameter of the aftertreatment system and (ii) output a signal that indicates a value of the measured operating parameter, and a control module configured to control the injector based on the signal outputted by the sensor. The control module includes a correction coefficient determination module configured to generate a correction coefficient based on the signal outputted by the sensor. The control module further includes an injector control module configured to receive an injector flow control signal, determine a pulse width modulation (PWM) signal based on at least the injector flow control signal, and generate an injector control signal that controls actuation of the injector based on at least the correction coefficient and the PWM signal.

A reductant delivery unit (RDU) for a selective catalytic reduction system, including a housing; a fluid inlet disposed at an upper portion of the housing; a fluid return outlet; a fluid nozzle outlet disposed at a lower portion of the housing; an injector disposed within the housing and configured to receive fluid from the fluid inlet and selectively discharge the fluid from the fluid nozzle outlet; and at least one fluid passageway disposed within or around the housing. The fluid passageway provides fluid communication along a first fluid path between the fluid inlet and the fluid nozzle outlet and along a second fluid path between the fluid inlet and the fluid return outlet so that the same fluid discharged by the injector is also used as a coolant for the RDU.

An exhaust after-treatment system has a DEF system with improved DEF purge cycling during which time DEF is returned to a DEF storage tank. The DEF system adapts its methodology based on a condition within the DEF system. A purge valve may be arranged in a doser feed line between a DEF supply module and a DEF doser module. A purging control system may be configured to control the purge valve based on detected states within the DEF system, such as a detected state that corresponds to a plugged DEF doser module. If a plugged doser module is detected, the purge valve may be opened to vent the doser module feed line to atmosphere which allows the DEF to be returned to the DEF storage tank without creating a siphon effect that could draw additional DEF from the DEF storage tank into the supply module.

A method for operating a feed module of an SCR catalytic converter system which has a feed pump, a feedback pump and a hydraulic interface channel. The feed module is operated in a test state in which a feed operation of the feed pump takes place and a feed operation of the feedback pump does not take place. Owing to a time profile of an MSP current (I.sub.MSP) of the feed pump it is decided in the test state whether the feed module is to change into a thawing state.

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.