The invention relates to a pump (2) intended to pump an additive in an SCR system for a vehicle. The pump is configured to rotate in a first direction of rotation in order to convey additive stored in a tank towards an injector via an injection channel. The pump includes a chamber (23) which houses a gear system (22). The chamber (23) is in fluid communication with the tank and the injection channel via an inlet channel (24) and an outlet channel (25) respectively. The pump is such that the inlet channel and the outlet channel are arranged so that after draining the injection channel, the chamber collects and retains the additive.

A device for adjusting and controlling the actual supplied amount of urea entering an exhaust system comprises an electronic control unit (1), a compressed air supply device (2), a urea storage device (3), a compressed air control device (4), a metering pump or a metering valve (5), a spray nozzle (6), a main pipeline (7), a urea pipeline (8), and a urea control device (9). The urea control device (9) is in communication with the electronic control unit (1) and controls the actual supplied amount of urea injected into the exhaust system from the spray nozzle according to the starting time point and the finishing time point. A method for adjusting and controlling the actual supplied amount of urea entering an exhaust system is also disclosed. The present device and method effectively prevent the excessive urea from being injected into the exhaust system, and enable the original exhaust system to match with stricter emission standards through a low cost improvement.

A reduction-causing agent supply device includes a tank to store a reduction-causing agent, a pumping unit to pump the reduction-causing agent, a reduction-causing agent supply passage to supply the reduction-causing agent, an injection nozzle to inject the reduction-causing agent into an exhaust pipe, a drawing-back unit to draw the reduction-causing agent toward the tank, and a controller. After stop of an engine, the controller performs: reduction-causing agent drawing-back process of drawing the reduction-causing agent toward the tank and introducing exhaust gas from the injection nozzle into the reduction-causing agent supply passage; and gas discharge process of supplying the reduction-causing agent to compress the exhaust gas inside the reduction-causing agent supply passage, discharging the compressed exhaust gas from the injection nozzle, and closing a valve of the injection nozzle before the reduction-causing agent reaches the injection nozzle.

The present application provides a reductant dosing system for an SCR catalyst comprising an injector, a storage tank and a reductant pump arranged in a first fluid line between the storage tank and the injector for pumping reductant from the storage tank to the injector. The reductant dosing system comprises pressurizing means for pressurizing the storage tank.

The invention relates to a liquid reservoir (1), in particular for an aqueous urea solution, comprising a buffer storage means (2) arranged on the bottom of the liquid reservoir (1) in the installation position, a liquid delivery unit (3), at least one, preferably a plurality of first filter elements (4) arranged on the bottom in the installation position outside the buffer storage means (2), each of which first filter elements is connected to the liquid delivery unit (3) via a liquid line (5), the first filter elements (4) being constructed such that the filter fabric of the first filter elements (4) is permeable to the liquid located in the liquid reservoir (1) and impermeable to air, a second filter element (6) being arranged between the interior of the buffer storage means (2) and the liquid delivery unit (3), which second filter element is constructed such that the filter fabric of the second filter element (6) is permeable to the liquid located in the liquid reservoir (1) and impermeable to air, the breakthrough pressure of the second filter element (6), at which air is delivered through the filter element, being greater than the breakthrough pressure of the first filter elements (4), furthermore comprising a first valve (7) between the liquid delivery unit (3) and the first filter elements (4), the opening pressure of the first valve (7) being smaller than the breakthrough pressure of the second filter element (6).

An exhaust aftertreatment system may include a reductant supply and diluent supply conduits, an injector and a control module. The reductant supply conduit includes a first valve controlling a flow of reductant through the reductant supply conduit. The diluent supply conduit includes a second valve controlling a flow of diluent through the diluent supply conduit. The injector is in fluid communication with the reductant supply conduit and the diluent supply conduit and is configured to provide fluid to an exhaust stream. The control module may control the first valve to provide a targeted amount of reductant through the injector. The control module may control the second valve to maintain a fluid flow rate through the injector that is at or above a minimum flow rate threshold of the injector based on a difference between a flow rate through the reductant supply conduit and the minimum flow rate threshold.

A sealing device which is used as part of an injector in a reductant delivery unit (RDU), where the RDU is part of a selective catalytic reduction (SCR) system for injecting diesel exhaust fluid (DEF) into an exhaust system, used for controlling exhaust emissions. This invention improves the purging efficiency of the RDU, in addition to improving the sealing performance of the unit by reducing the fluid volume to be evacuated from the injector, and provides an additional sealing barrier to reduce the sealing load of the existing sealing elements. An additional sealing device having a ring seal and a stopper element (also referred to as a “plug”) is pressed into the upper valve body of the injector, which results in a reduced fluid volume that is left behind after a purging event, due to the reduced initial volume at the beginning of the purge.

An exhaust gas control apparatus for an internal combustion engine includes an addition valve, a tank, a urea water passage, a pump, a nitrogen oxides catalyst, and an electronic control unit. The electronic control unit is configured to: control the pump, as a first control, such that a specified amount of the urea water stored in the addition valve and the urea water passage is returned to the tank after the internal combustion engine is stopped; control the pump, as a second control, such that the specified amount or more of the urea water in the tank is discharged from the tank to the urea water passage after the first control is executed; and control the pump, as a third control, such that all the urea water stored in the addition valve and the urea water passage is returned to the tank after the second control is executed.

An object is to prevent abrasion inside an addition valve and clogging of the addition valve due to an increase in the particle diameter of precipitates. A first control is performed by which a pump is caused to operate in such a way as to return urea solution contained in the addition valve and a urea solution channel to a tank by a predetermined quantity. After the lapse of a certain time after the end of the first control, a second control is performed by which the pump is caused to operate in such a way as to return the urea solution remaining in the addition valve and the urea solution channel thoroughly to the tank.

In a method for operating a urea dosing system in an exhaust aftertreatment system (EATS) of an engine, an ambient temperature is measured in an environment in which the EATS is disposed, one or more temperatures associated with the EATS to which there is a relationship to a temperature of area in the urea dosing system are monitored. After turning off the engine, whether urea in the urea dosing system is subject to freezing is determined based on the measured ambient temperature and the one or more monitored temperatures. A reversion operation is performed after turning off the engine with a delay until one or more events occur, the one or more events including determining that urea in the urea dosing system is subject to freezing. An engine system is also provided.