Robert Boschgmbh

Matthias Burger

Hans-Christoph Magel

Andreas Kellner

Nadja Eisenmenger

Gert Wolf

Wolfgang Klenk

Markus Buerglin

Martin Braun

Dirk Vahle

Martin Katz

Dirk Von Meduna

Wilhelm Dueck

Reinold Weinmann

Franz-Josef Trompeter

Sascha Rademann

Christian Faltin

Matthias Kruse

Stephan Amelang

Dietrich Klauk

Susanne Spindler

A method of operating a dosing device. A dosing valve is provided with low-pressure and high-pressure chambers delimited by a piston whose travel is limited to a predefined maximum stroke. A pump operates to deliver the liquid at pre-delivery pressure. The dosing valve actuates under direction of a control unit by opening a 2/2 directional valve to direct the pumped liquid into the low-pressure chamber, and in response, the piston initiates a stroke. The liquid is injected from the high-pressure chamber into the exhaust-gas stream during the stroke of the piston, and the injection stops when the piston reaches maximum stroke. The control unit holds the directional valve open for longer than the piston requires to perform its maximum stroke so that the dosing valve delivers a predetermined volumetric dose of the liquid into the exhaust-gas stream, the predetermined volumetric dose corresponding directly to the maximum stroke of the piston.

Method of operating a dosing device

A method for operating a reagent metering system which meters a reagent into an exhaust duct of an internal combustion engine upstream of an SCR catalytic converter, in which, after the metering operation is ended, at least part of the reagent metering system is emptied by back-suction by means of a reciprocating pump. The procedure according to the invention is distinguished in that during the back-suction, a stop determination determines the flight time of a reciprocating piston of the reciprocating pump from a starting time as far as the stop time, in that a comparator compares the flight time determined with a flight time threshold value, and in that the activation power of the reciprocating pump is reduced if the flight time determined is less than the flight time threshold value.

Method for operating a reagent metering system, device for carrying out the method, computer program and computer program product

The invention relates to a device and method for metering a liquid, in particular a fuel, into an exhaust gas tract of an internal combustion engine, wherein the device comprises at least one injection valve that can be closed by a closing member and that has cooling circuit for regulating the temperature in the injection valve, and wherein a throttle element is connected upstream of the injection valve to control, by closed loop or open loop, the quantity of a volume flow of the liquid through the injection valve, in particular through the cooling circuit of the injection valve, wherein the injection valve opens when the throttle element de-throttles the volume flow of the liquid to the injection valve.

Device and method for metering a liquid into the exhaust tract of an internal combustion engine

The present invention relates to a dosing valve and to a dosing device () for introducing a liquid medium into an exhaust-gas stream of an internal combustion engine () of a motor vehicle. The dosing device () has a pump () for delivering the liquid medium. The medium is injected into the exhaust-gas stream by means of a dosing valve () which can be controlled by way of an electromagnet (). The dosing device () comprises a housing () with a stepped bore (), wherein a pump sleeve () is guided sealingly in one portion () of the stepped bore (). A hollow-bored piston () is guided sealingly in a central bore () of the pump sleeve (). In a low-pressure chamber (), an armature () is fastened to the piston (), and furthermore a magnet sleeve () is fastened to the housing (). A stop sleeve () is arranged on a side of the low-pressure chamber () situated opposite the magnet sleeve (), wherein a stroke of the piston () is limited by the magnet sleeve () and/or by the stop sleeve ().

Dosing device

A method for verifying the plausibility of a measuring device for determining a quality of an aqueous urea solution in a reservoir of an SCR catalyst system comprises determining whether a filling of the reservoir has taken place, determining the quality of the aqueous urea solution in the reservoir and detecting whether an error of the measuring device is present or whether the reservoir was filled with an aqueous urea solution, the quality of which deviates from a default value consisting of a filling status of the reservoir and the quality of the aqueous urea solution in said reservoir.

Method for verifying the plausibility of a measuring device for determining the quality of an aqueous urea solution in a reservoir of an SCR catalyst system

The invention relates to a fuel injector and, in particular, to a common-rail injector for injecting fuel into a combustion chamber of an internal combustion engine with a multi-part injection valve element, which can be adjusted between an open position and a closed position. A first part and a second part of the injection valve element are coupled to one another via a hydraulic coupler, which is bounded radially by a first guide for the first part and by a second guide for the second part. According to the invention, at least some sections of the first and the second guide are surrounded at their outer radii by fuel under high pressure, and the pressure realized in the hydraulic coupler is lower than the pressure radially outside the guides.

Fuel injector

The invention proposes a method for metering a reagent, in which the reagent is sprayed into a spray tube () via an electrically activated metering valve (), and is mixed in the spray tube () with compressed air, and in which the reagent mixed with compressed air is introduced by means of the spray tube () into an exhaust gas duct () and is atomized, and a device for carrying out the method. The procedure according to the invention is distinguished in that the duration of the metering valve activation signal () is corrected depending on the differential pressure between the hydraulic pressure (p_Rea_hyd) of the reagent in the metering valve () and the pneumatic pressure (p_D_pneu) in the spray tube (). The procedure according to the invention permits a high degree of accuracy in the metering of the reagent.

Method for metering a reagent into an exhaust gas duct and device for carrying out the method

The invention relates to a fuel injector, in particular a common rail injector, for injecting fuel into a combustion chamber of an internal combustion engine. The fuel injector has a multi-part injection valve element, which is adjustable between a closing position and an opening position and includes a first part and at least one second part that is adjustable relative to the first part. The first and second parts are coupled to one another via a hydraulic coupler volume. According to the invention, it is provided that the first part is guided in the second part, or the second part is guided in the first part, and that the coupler volume communicates with an injector volume via at least one throttle arrangement. The throttle arrangement is embodied such that the volumetric through flow increases only disproportionately little with an increasing pressure difference between the coupler volume and the injector volume.

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Murr, Germany

Matthias Burger