A reductant delivery system for an internal combustion engine is arranged to inject a reductant into the exhaust aftertreatment system upstream of a catalytic device. A method for controlling the reductant delivery system includes operating the fluidic pump at a preset state, operating the injector at a zero-flow state, and monitoring, via a pressure sensor, a pressure in the reductant delivery system upstream of the injector to determine a zero-flow pressure. The injector is activated under a preset condition and an actual pressure drop upstream of the injector is monitored. A pressure drop deviation is determined based upon the actual pressure drop upstream of the injector and an expected pressure drop upstream of the injector. An adjustment to the activation of the injector is determined based upon the pressure drop deviation, and the injector is controlled based upon the adjustment.

A lance injector assembly for an exhaust component is provided. The lance injector assembly includes a lance and a poppet valve. The lance includes a lance housing, a supply passage fluidly coupled to a reductant source and terminating at a nozzle orifice, and a return passage fluidly coupled to the reductant source. The poppet valve is positioned downstream of the nozzle orifice and includes a poppet movable between a closed position and an open position. When operating in a recirculation mode, the poppet is in the closed position to permit a full portion of reductant supplied to the lance from the reductant source to return to the reductant source. When operating in an injection mode, the poppet is in the open position to permit a first portion of reductant to flow from the nozzle orifice and a second portion of reductant to return to the reductant source.

A reduction in measurement accuracy of a concentration sensor is minimized. An exhaust gas purifying device of a work machine includes a reduction catalyst that is placed in an exhaust flow passage of an exhaust gas of an engine and uses a reducing agent to reduce and purify nitrogen oxides in the exhaust gas, and a reducing agent injector to inject the reducing agent into the exhaust flow passage. The exhaust gas purifying device of a work machine includes: a storage unit that stores the reducing agent; a concentration sensor that has a sensing part placed within the storage unit to detect a concentration of the reducing agent; an air-bubble removal device that injects the reducing agent toward the sensing part; and a reducing agent pump that supplies the reducing agent in the storage unit to the air-bubble removal device.

Disclosed is an exhaust gas aftertreatment system (1) for a diesel engine, the exhaust gas aftertreatment system comprising: a treatment agent tank (2) for storing an exhaust gas treatment agent; a metering injection module (4), with the injection of the metering injection module (4) being controlled with a determined duty ratio signal according to a desired injection amount; a supply module (3) connected between the treatment agent tank (2) and the metering injection module (4) for supplying the exhaust gas treatment agent to the metering injection module (4); an exhaust gas treatment agent pipe (6) connected between the metering injection module (4) and the supply module (3); a pressure sensor for measuring the system pressure in the exhaust gas treatment agent pipe (6); and a controller (7); wherein the controller (7) is configured to receive a system pressure signal from the pressure sensor during injection of the metering injection module (4), and detect an injection abnormality of the metering injection module (4) based on at least a first amount, which represents an actual injection amount and is determined by the system pressure signal, and a second amount, which represents a theoretical injection amount and is determined by a corresponding duty ratio signal. A corresponding injection abnormality detection method is further disclosed. The injection abnormality detection method is simple and reliable.

An abnormality determination device is used in an exhaust gas purification system. The exhaust gas purification system is disposed in an exhaust gas passage of an internal-combustion engine and includes an injection valve for injecting a liquid reducing agent to a NO.sub.x purification catalyst for purifying NO.sub.x in an exhaust gas, and a pump for pressurizing and supplying the reducing agent to the injection valve via a reducing agent passage. The abnormality determination device includes an acquisition section acquiring a rotation speed of the pump when the injection valve is injecting the reducing agent as an injection time rotation speed; and a determiner determining whether the injection valve has an abnormality based on the injection time rotation speed.

Vehicle exhaust system uses delta pressure based estimation of accumulated soot within a diesel particulate filter. The exhaust system has a diesel oxidation catalyst and a diesel particulate filter. A fuel injector is connected upstream from the diesel oxidation catalyst and the diesel particulate filter. A delta pressure sensor measures difference in pressure at inlet and outlet of the diesel particulate filter. A controller determines when to regenerate the diesel particulate filter based on an estimated amount of soot. The controller, in a first regeneration mode, causes the fuel injector to inject fuel at a first rate into the exhaust stream, and to re-evaluate amount of soot accumulated within the diesel particulate filter under increased volumetric flow. The controller, in a second regeneration mode, causes the fuel injector to inject fuel at a second rate into the exhaust stream in order to combust soot trapped in the diesel particulate filter.

A reductant insertion assembly for inserting a reductant into an aftertreatment system includes: a pump assembly comprising a pump that includes a pump outlet; a first metering assembly fluidly coupled to the pump outlet, the first metering assembly comprising a first metering manifold; and a second metering assembly fluidly coupled in series with the pump, the second metering assembly being a separate structure from the first metering assembly and comprising a second metering manifold removably coupled to the first metering manifold. The pump is configured to pump the reductant to the first metering assembly, and to the second metering assembly via the first metering assembly.

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.

A method for identifying deviations in quantity in the case of a fluidic metering system (100-165), in particular an internal combustion engine of a motor vehicle, in which at least one conveying pump (125) for conveying a fluid, and at least one pressure sensor (135) for determining a fluidic pressure in the metering system (100-165), are disposed, wherein it is provided in particular that a test admeasurement of fluid is carried out (205), that a temporal pressure drop in the metering system (100-165) is detected (210), that the detected temporal pressure drop is compared with a pressure drop (215) that is to be theoretically expected (220), and that a deviation in quantity of the metering system (100-165) is determined based on the result of the comparison (225).

Disclosed is a method for diagnosing functionality of dosing units of a fluid dosing system comprising at least two dosing units, a tank unit for holding a fluid, and a pump unit for pressurizing the fluid for the dosing units. The method comprises determining a first hydraulic stiffness value on the basis of first pressure variations and determining a second hydraulic stiffness value on the basis of said second pressure variations. The first hydraulic stiffness value and second hydraulic stiffness value are compared. In a case where the first hydraulic stiffness value and second hydraulic stiffness value differ to a certain extent, concluding that malfunction of at least one of said dosing units is at hand, and in a case where the first hydraulic stiffness value and the second hydraulic stiffness value do not differ to said certain extent, concluding that the first and second dosing units function as intended.