EP2294294B1 - Dosing system for a liquid medium, particularly a urea-water solution - Google Patents

Dosing system for a liquid medium, particularly a urea-water solution Download PDF

Info

Publication number
EP2294294B1
EP2294294B1 EP09765665A EP09765665A EP2294294B1 EP 2294294 B1 EP2294294 B1 EP 2294294B1 EP 09765665 A EP09765665 A EP 09765665A EP 09765665 A EP09765665 A EP 09765665A EP 2294294 B1 EP2294294 B1 EP 2294294B1
Authority
EP
European Patent Office
Prior art keywords
valve
dosing
check valve
pressure
metering
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Not-in-force
Application number
EP09765665A
Other languages
German (de)
French (fr)
Other versions
EP2294294A1 (en
Inventor
Guenther Vogt
Stefan Loesch
Christian Basan
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Robert Bosch GmbH
Original Assignee
Robert Bosch GmbH
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Robert Bosch GmbH filed Critical Robert Bosch GmbH
Publication of EP2294294A1 publication Critical patent/EP2294294A1/en
Application granted granted Critical
Publication of EP2294294B1 publication Critical patent/EP2294294B1/en
Not-in-force legal-status Critical Current
Anticipated expiration legal-status Critical

Links

Images

Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
    • F01N3/00—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust
    • F01N3/08—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous
    • F01N3/10—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust
    • F01N3/18—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust characterised by methods of operation; Control
    • F01N3/20—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust characterised by methods of operation; Control specially adapted for catalytic conversion ; Methods of operation or control of catalytic converters
    • F01N3/206—Adding periodically or continuously substances to exhaust gases for promoting purification, e.g. catalytic material in liquid form, NOx reducing agents
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04B—POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS
    • F04B13/00—Pumps specially modified to deliver fixed or variable measured quantities
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
    • F01N2610/00—Adding substances to exhaust gases
    • F01N2610/01—Adding substances to exhaust gases the substance being catalytic material in liquid form
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
    • F01N2610/00—Adding substances to exhaust gases
    • F01N2610/14—Arrangements for the supply of substances, e.g. conduits
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
    • F01N2610/00—Adding substances to exhaust gases
    • F01N2610/14—Arrangements for the supply of substances, e.g. conduits
    • F01N2610/1433—Pumps
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T137/00—Fluid handling
    • Y10T137/7722—Line condition change responsive valves
    • Y10T137/7837—Direct response valves [i.e., check valve type]
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T137/00—Fluid handling
    • Y10T137/7722—Line condition change responsive valves
    • Y10T137/7837—Direct response valves [i.e., check valve type]
    • Y10T137/7904—Reciprocating valves
    • Y10T137/7922—Spring biased

Definitions

  • the emission limit values for nitrogen oxides in motor vehicles whose weight exceeds a certain limit require exhaust aftertreatment devices which carry out a selective catalytic reduction (SCR) of the nitrogen oxides contained in the raw emissions of the internal combustion engine.
  • SCR selective catalytic reduction
  • An example of such an exhaust aftertreatment device is from the DE 10 2006 012 855 A1 known.
  • an aqueous urea solution is stored in a tank and injected by a metering pump and with the aid of a metering valve as needed in an exhaust pipe of the internal combustion engine.
  • That from the DE 10 2006 012 855 A1 known metering valve is pressure-actuated. This means that it opens as soon as a predetermined opening pressure is exceeded at the inlet of the metering valve. As soon as the opening pressure is fallen below, the dosing valve closes again.
  • the pressure-operated metering valve is a "passive" component that does not require its own control. Also, signal lines or control lines from a controller to the metering valve are not required.
  • the WO 02/079616 describes an apparatus for aftertreating exhaust gases with a mixing chamber for mixing reducing agent with air.
  • the invention has for its object to further develop a metering system of the type mentioned in that the performance characteristics, in particular the precision is injected with the reducing agent in the exhaust pipe, is improved.
  • tightness of the metering valve should be increased during operation and after switching off the internal combustion engine.
  • a metering system for a liquid medium for a liquid medium, in particular a liquid reducing agent, such as an aqueous urea-water solution
  • a liquid medium in particular a liquid reducing agent, such as an aqueous urea-water solution
  • a tank with a metering pump and with a metering valve
  • a pressure side of the diaphragm pump and the metering valve by a first line are connected to each other and wherein the tank and a suction side of the metering pump are connected to each other by a second line, achieved in that in the first line, a first check valve is provided.
  • the first check valve prevents the first line from draining between two actuations of the metering valve. This would mean that during the subsequent actuation of the metering pump, the quantity of urea-water solution predefined by an engine control unit is not injected. As a result, the quality of the exhaust aftertreatment would suffer and emissions would rise.
  • the first check valve is designed as a double-acting check valve, and that a second output or a second valve seat of the first check valve is hydraulically connected to the tank or the suction side of the metering pump via a connecting line. This prevents unintentional and reopening of the metering valve after switching off the metering pump.
  • the first check valve In the promotion of liquid reducing agent through the metering pump opens the first check valve and the reducing agent passes from the metering pump in the first line. After the delivery and injection of the reducing agent through the metering valve in the exhaust system, the first check valve closes again. The closing of the metering valve creates a pressure surge in the first line, which is reflected by a single-acting check valve and runs again to the metering valve. There, the pressure surge can trigger a brief opening of the metering valve. As a result, a non-negligible amount of the reducing agent is undesirably injected into the exhaust pipe. This effect increases with increasing closing speed of the metering valve.
  • the first check valve is designed as a double-acting check valve, then closes the check valve during the promotion of the metering pump, a connecting line between the first line and the tank of the dosing. In this position, the metering system behaves, not unlike a metering system according to the invention with a simply designed check valve.
  • a lifting movement of the metering pump is at least partially transmitted to the valve member of the first check valve.
  • the metering pump initially executes a delivery stroke and conveys the liquid reducing agent into the first conduit.
  • the valve member of the first check valve opens when the pressure in the metering pump is greater than the opening pressure of the first check valve, and the promotion of reducing agent to the metering valve begins.
  • the inventive transmission of the lifting movement of the metering pump on the valve member is namely guaranteed that the first check valve remains open during the suction stroke, regardless of the pressure conditions.
  • a predetermined amount of urea water solution from the first line is sucked back into the metering pump, so that a controlled and rapid pressure reduction takes place in the first line and in the metering valve.
  • the metering valve closes quickly and tightly, so that the dosage of the reducing agent is carried out with higher accuracy.
  • the lifting movements of the metering pump and the valve member are decoupled, so that the first check valve can fulfill its function known from the prior art and hydraulically separates the first line from the metering pump ,
  • the venting of the metering system is facilitated by the coupling of valve member and stroke of the metering pump.
  • a compressible medium such as air or steam
  • the first check valve is spring-loaded.
  • a pressure-holding valve in particular an adjustable pressure-holding valve, is provided in the connecting line.
  • the opening pressure of the pressure holding valve is chosen to be lower than the opening pressure of the metering valve, since only then can the reflection of pressure surges be reliably prevented. Due to the holding pressure of the pressure holding valve, it is possible to suppress the formation of vapor bubbles within the first conduit or of the metering system and thereby further improve the function and accuracy with which the reducing agent is injected and metered.
  • FIG. 1 is an internal combustion engine 1 with an exhaust aftertreatment device 3 greatly simplified and shown schematically.
  • the exhaust gas aftertreatment device 3 comprises an exhaust gas pipe 5, an oxidation catalytic converter 7 and an SCR catalytic converter 11.
  • the flow direction of the exhaust gas through the exhaust gas pipe 5 is indicated by arrows (without reference numerals).
  • a metering valve 13 for the reducing agent is arranged upstream of the SCR catalytic converter 11 on the exhaust gas pipe 5.
  • the metering valve 13 injects reducing agent upstream of the SCR catalyst 11 into the exhaust pipe 5 as needed.
  • the metering system comprises the metering valve 13, a metering pump 15 and a storage tank 17.
  • the metering pump 15 is in FIG. 1 only shown as "black box”. Details are given below with reference to Figures 2 and 3 explained.
  • a first line 19 is provided between the tank 17 and the metering pump 15 and the metering valve 13.
  • a second conduit 21 is provided between the tank 17 and the metering pump 15 and the metering valve 13.
  • control unit 29 controls the internal combustion engine 1 and among other things, the metering pump 15.
  • the line connection between the control unit 29 and the metering pump 15 is indicated by a dashed arrow (without reference numeral) in FIG. 1 shown.
  • the metering valve 13 is shown schematically as a spring-loaded valve.
  • the metering pump 15 is designed as a diaphragm pump with a membrane 31.
  • the diaphragm 31 of the metering pump 15 is actuated by an electromagnet comprising a coil 33 and an armature 35.
  • the coil 33 When the coil 33 is energized, the armature 35 and with it the membrane 31 moves in FIG. 2 up and performs a delivery stroke.
  • the first check valve 39 is in FIG. 2 shown as a flutter valve comprising a valve member 41 and a valve seat 43.
  • the valve member 41 is formed as an elastic membrane of a plastic, such as EPDM, or metal.
  • a spring 44 exerts a force in the closing direction of the first check valve 39 on the valve member 41.
  • the lifting movement of the diaphragm 31 is partially transmitted to the valve member 41 via a plunger 45. This happens because in the rest position of the membrane 31 and when the first check valve 39 is closed, the plunger 45 does not rest on the membrane 31.
  • a second check valve 46 is arranged, which prevents 15 reducing agent from the delivery chamber 37 in the second conduit 21 and the tank 17 can flow back during the delivery stroke of the metering pump.
  • This second check valve 46 is not spring-loaded as a rule. It will too often designed as a flutter valve, although it is in FIG. 2 and 3 symbolically represented as a ball valve.
  • the first check valve 39 is formed as a double-acting check valve and shown symbolically as a ball valve, although it is also usually a flutter or sniffer valve.
  • the first check valve 39 has not only the first valve seat 43, but also a second valve seat 47, the output of which is hydraulically connected to the tank 17 via a connecting line 49 and the second line 21.
  • the pressure in the delivery chamber 37 rises above the pressure prevailing in the first line 19.
  • the valve member 41 lifts off from the first valve seat 43 and closes the connection line 49 because it is sealingly pressed onto the second valve seat 47.
  • the delivery stroke is the same in the second embodiment, as in the first embodiment according to FIG. 2 explained.
  • the pressure conditions in the first check valve 39 ensure that the valve member 41 is pressed against the first valve seat 43 and thereby interrupted the hydraulic connection between the pumping chamber 37 and the first line 19 becomes.
  • a hydraulic connection between the first line 19, connecting line 49, second line 21 and tank 17 is opened, so that possibly run out of the metering valve 13 pressure surges run into the tank 17 and are dissipated there.
  • a pressure-maintaining valve 51 is provided in the connecting line 49.
  • the pressure holding valve 51 serves to maintain a minimum settable pressure in the first conduit 19 so that the boiling point of the reducing agent in the first conduit 19 is increased and the formation of vapor bubbles is suppressed.
  • the opening pressure of the pressure holding valve 49 is lower than the opening pressure of the metering valve 13, so that the closing movement and the sealing of the metering valve 13 are not prevented by the pressure-holding valve 51.
  • this pressure surges whose amplitude is higher than the opening pressure of the pressure holding valve 51 continue to flow almost unhindered in the tank 17 and are dissipated there.
  • the pressure holding valve 51 is adjustable with respect to its holding pressure, so that it can be adjusted according to the prevailing operating conditions. This makes it possible, for example, after stopping the engine to change the holding pressure, so that the first
  • Line 19 is completely relieved of pressure and thereby the metering valve 13 is completely sealed even over a longer period. If the risk of vapor bubble formation occurs during the operation of the internal combustion engine, the holding pressure of the pressure holding valve 51 can be increased accordingly.
  • FIG. 3b is a block diagram of the embodiment according to FIG. 3a shown.
  • various pressure sensors 53.1, 53.2 and 53.3 are shown, which are installed as required and connected to the control unit 29.

Landscapes

  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Health & Medical Sciences (AREA)
  • Toxicology (AREA)
  • Combustion & Propulsion (AREA)
  • Exhaust Gas After Treatment (AREA)

Abstract

The invention relates to a dosing system for a liquid reduction medium enabling precise dosing of the reduction medium in the exhaust gas system of an internal combustion engine. This is carried out particularly by using a quick and safe closing of a pressure-actuated dosing valve. Simultaneously, the dosing system according to the invention also enables the dissipation of the pressure impulses resulting due to the closing movement of the dosing valve.

Description

Stand der TechnikState of the art

Die Immissionsgrenzwerte für Stickoxide erfordern bei Kraftfahrzeugen, deren Gewicht eine bestimmte Grenze überschreitet, Abgasnachbehandlungseinrichtungen, die eine selektive katalytische Reduktion (SCR) der in den Rohemissionen der Brennkraftmaschine enthaltenen Stickoxide vornimmt. Dieses sogenannte SCR-Verfahren zur Abgasreinigung ist aus dem Stand der Technik bekannt, sodass auf eine detaillierte Erläuterung der bei diesem Verfahren ablaufenden chemischen Vorgänge verzichtet werden kann.The emission limit values for nitrogen oxides in motor vehicles whose weight exceeds a certain limit require exhaust aftertreatment devices which carry out a selective catalytic reduction (SCR) of the nitrogen oxides contained in the raw emissions of the internal combustion engine. This so-called SCR process for exhaust gas purification is known from the prior art, so that it is possible to dispense with a detailed explanation of the chemical processes taking place in this process.

Ein Beispiel einer solchen Abgasnachbehandlungseinrichtung ist aus der DE 10 2006 012 855 A1 bekannt. Dort wird eine wässerige Harnstofflösung in einem Tank gespeichert und von einer Dosierpumpe und mit Hilfe eines Dosierventils bedarfsabhängig in ein Abgasrohr der Brennkraftmaschine eingedüst. Das aus der DE 10 2006 012 855 A1 bekannte Dosierventil ist druckbetätigt. Dies bedeutet, dass es öffnet, sobald an dem Eingang des Dosierventils ein vorgegebener Öffnungsdruck überschritten wird. Sobald der Öffnungsdruck unterschritten wird, schließt das Dosierventil wieder.An example of such an exhaust aftertreatment device is from the DE 10 2006 012 855 A1 known. There, an aqueous urea solution is stored in a tank and injected by a metering pump and with the aid of a metering valve as needed in an exhaust pipe of the internal combustion engine. That from the DE 10 2006 012 855 A1 known metering valve is pressure-actuated. This means that it opens as soon as a predetermined opening pressure is exceeded at the inlet of the metering valve. As soon as the opening pressure is fallen below, the dosing valve closes again.

Das druckbetätigte Dosierventil ist ein "passives" Bauteil, das keine eigene Ansteuerung erfordert. Auch sind Signalleitungen bzw. Steuerleitungen von einem Steuergerät zum Dosierventil nicht erforderlich.The pressure-operated metering valve is a "passive" component that does not require its own control. Also, signal lines or control lines from a controller to the metering valve are not required.

Die WO 02/079616 beschreibt eine Vorrichtung zum Nachbehandeln von Abgasen mit einer Mischkammer zum Mischen von Reduktionsmittel mit Luft.The WO 02/079616 describes an apparatus for aftertreating exhaust gases with a mixing chamber for mixing reducing agent with air.

Offenbarung der ErfindungDisclosure of the invention

Der Erfindung liegt der Aufgabe zugrunde, ein Dosiersystem der eingangs genannten Art dahingehend weiterzuentwickeln, dass die Gebrauchseigenschaften, insbesondere die Präzision mit dem Reduktionsmittel in das Abgasrohr eingedüst wird, verbessert wird. Außerdem sollen Dichtheit des Dosierventils während des Betriebs und nach dem Abstellen der Brennkraftmaschine erhöht werden.The invention has for its object to further develop a metering system of the type mentioned in that the performance characteristics, in particular the precision is injected with the reducing agent in the exhaust pipe, is improved. In addition, tightness of the metering valve should be increased during operation and after switching off the internal combustion engine.

Diese Aufgabe wird erfindungsgemäß bei einem Dosiersystem für ein flüssiges Medium, insbesondere einem flüssigen Reduktionsmittel, wie zum Beispiel eine wässerige Harnstoff-Wasser-Lösung, mit einem Tank, mit einer Dosierpumpe und mit einem Dosierventil, wobei eine Druckseite der Membranpumpe und das Dosierventil durch eine erste Leitung miteinander verbunden sind und wobei der Tank und eine Saugseite der Dosierpumpe durch eine zweite Leitung miteinander verbunden sind, dadurch gelöst, dass in der ersten Leitung ein erstes Rückschlagventil vorgesehen ist.This object is achieved in a metering system for a liquid medium, in particular a liquid reducing agent, such as an aqueous urea-water solution, with a tank, with a metering pump and with a metering valve, wherein a pressure side of the diaphragm pump and the metering valve by a first line are connected to each other and wherein the tank and a suction side of the metering pump are connected to each other by a second line, achieved in that in the first line, a first check valve is provided.

Das erste Rückschlagventil verhindert, dass sich die erste Leitung zwischen zwei Betätigungen des Dosierventils entleert. Dies hätte zur Folge, dass bei der darauf folgenden Betätigung der Dosierpumpe nicht die von einem Motorsteuergerät vorgegebene Menge an Harnstoffwasserlösung eingedüst wird. Dadurch würde die Qualität der Abgasnachbehandlung leiden und die Emissionen ansteigen.The first check valve prevents the first line from draining between two actuations of the metering valve. This would mean that during the subsequent actuation of the metering pump, the quantity of urea-water solution predefined by an engine control unit is not injected. As a result, the quality of the exhaust aftertreatment would suffer and emissions would rise.

Dabei ist vorgesehen, dass das erste Rückschlagventil als doppeltwirkendes Rückschlagventil ausgebildet ist, und dass ein zweiter Ausgang bzw. ein zweiter Ventilsitz des ersten Rückschlagventils mit dem Tank bzw. der Saugseite der Dosierpumpe über eine Verbindungsleitung hydraulisch in Verbindung steht. Dadurch wird ein ungewolltes und erneutes Öffnen des Dosierventils nach dem Abschalten der Dosierpumpe verhindert.It is provided that the first check valve is designed as a double-acting check valve, and that a second output or a second valve seat of the first check valve is hydraulically connected to the tank or the suction side of the metering pump via a connecting line. This prevents unintentional and reopening of the metering valve after switching off the metering pump.

Bei der Förderung von flüssigem Reduktionsmittel durch die Dosierpumpe öffnet sich das erste Rückschlagventil und das Reduktionsmittel gelangt aus der Dosierpumpe in die erste Leitung. Nach der Förderung und Einspritzung des Reduktionsmittels durch das Dosierventil in die Abgasanlage schließt das erste Rückschlagventil wieder. Durch das Schließen des Dosierventils entsteht ein Druckstoß in der ersten Leitung, der an einem einfach wirkenden Rückschlagventil reflektiert wird und wieder zum dem Dosierventil läuft. Dort kann der Druckstoß eine kurzzeitige Öffnung des Dosierventils auslösen. In Folge dessen wird eine nicht vernachlässigbare Menge des Reduktionsmittels ungewollterweise in das Abgasrohr eingedüst. Dieser Effekt nimmt mit zunehmender Schließgeschwindigkeit des Dosierventils zu.In the promotion of liquid reducing agent through the metering pump opens the first check valve and the reducing agent passes from the metering pump in the first line. After the delivery and injection of the reducing agent through the metering valve in the exhaust system, the first check valve closes again. The closing of the metering valve creates a pressure surge in the first line, which is reflected by a single-acting check valve and runs again to the metering valve. There, the pressure surge can trigger a brief opening of the metering valve. As a result, a non-negligible amount of the reducing agent is undesirably injected into the exhaust pipe. This effect increases with increasing closing speed of the metering valve.

Wenn nun das erste Rückschlagventil als zweifach wirkendes Rückschlagventil ausgebildet wird, dann verschließt das Rückschlagventil während der Förderung der Dosierpumpe eine Verbindungsleitung zwischen der ersten Leitung und dem Tank des Dosiersystems. In dieser Stellung verhält sich das Dosiersystem, nicht anders als ein erfindungsgemäßes Dosiersystem mit einem einfach ausgebildeten Rückschlagventil.If now the first check valve is designed as a double-acting check valve, then closes the check valve during the promotion of the metering pump, a connecting line between the first line and the tank of the dosing. In this position, the metering system behaves, not unlike a metering system according to the invention with a simply designed check valve.

Wenn aber der Förderhub der Dosierpumpe beendet ist, wird das Ventilglied des zweifach wirkenden Rückschlagventils wieder in den Ventilsitz gedrückt und die hydraulische Verbindung zwischen Dosierpumpe und Dosierventil ist unterbrochen. Gleichzeitig wird über die Verbindungsleitung eine hydraulische Verbindung zwischen der ersten Leitung zum drucklosen Tank hergestellt, sodass ein vom Dosierventil ausgehender Druckstoß nicht am ersten Rückschlagventil reflektiert wird, sondern in den Tank läuft und dort dissipiert wird. Dadurch werden die oben geschilderten ungewollten Nachspritzer aufgrund von Druckstößen innerhalb des Dosiersystems vermieden.But when the delivery stroke of the metering pump is completed, the valve member of the double-acting check valve is pushed back into the valve seat and the hydraulic connection between the metering pump and metering valve is interrupted. At the same time, a hydraulic connection between the first line and the pressureless tank is made via the connecting line made, so that an outgoing from the metering pressure surge is not reflected at the first check valve, but runs into the tank and is dissipated there. As a result, the above-described unwanted Nachspritzer be avoided due to pressure surges within the metering.

In weiterer vorteilhafter Ausgestaltung der Erfindung ist vorgesehen, dass eine Hubbewegung der Dosierpumpe mindestens teilweise auf das Ventilglied des ersten Rückschlagventils übertragen wird.In a further advantageous embodiment of the invention it is provided that a lifting movement of the metering pump is at least partially transmitted to the valve member of the first check valve.

Dies bedeutet, dass, ausgehend von einem Ruhezustand der Dosierpumpe zunächst die Dosierpumpe einen Förderhub ausführt und das flüssige Reduktionsmittel in die erste Leitung fördert. Bei einem Förderhub öffnet das Ventilglied des ersten Rückschlagventils sobald der Druck in der Dosierpumpe größer ist als der Öffnungsdruck des ersten Rückschlagventils, und die Förderung von Reduktionsmittel zum Dosierventil beginnt.This means that, starting from an idle state of the metering pump, the metering pump initially executes a delivery stroke and conveys the liquid reducing agent into the first conduit. In a delivery stroke, the valve member of the first check valve opens when the pressure in the metering pump is greater than the opening pressure of the first check valve, and the promotion of reducing agent to the metering valve begins.

Durch die erfindungsgemäße Übertragung der Hubbewegung der Dosierpumpe auf das Ventilglied ist nämlich gewährleistet, dass das erste Rückschlagventil während des Saughubs unabhängig von den Druckverhältnissen geöffnet bleibt. Infolge dessen wird eine vorgegebene Menge von Harnstoffwasserlösung aus der ersten Leitung wieder in die Dosierpumpe zurückgesaugt, sodass ein kontrollierter und rascher Druckabbau in der ersten Leitung und im Dosierventil stattfindet. Dadurch schließt das Dosierventil rasch und dicht, sodass die Dosierung des Reduktionsmittels mit höherer Genauigkeit erfolgt.By the inventive transmission of the lifting movement of the metering pump on the valve member is namely guaranteed that the first check valve remains open during the suction stroke, regardless of the pressure conditions. As a result, a predetermined amount of urea water solution from the first line is sucked back into the metering pump, so that a controlled and rapid pressure reduction takes place in the first line and in the metering valve. As a result, the metering valve closes quickly and tightly, so that the dosage of the reducing agent is carried out with higher accuracy.

Kurz bevor die Dosierpumpe ihren Ausgangspunkt erreicht hat und der Hub der Dosierpumpe gleich Null ist, werden die Hubbewegungen der Dosierpumpe und des Ventilglieds entkoppelt, sodass das erste Rückschlagventil seiner aus dem Stand der Technik bekannten Funktion nachkommen kann und die erste Leitung von der Dosierpumpe hydraulisch trennt.Just before the metering pump has reached its starting point and the stroke of the metering pump is equal to zero, the lifting movements of the metering pump and the valve member are decoupled, so that the first check valve can fulfill its function known from the prior art and hydraulically separates the first line from the metering pump ,

Schließlich wird durch die Kopplung von Ventilglied und Hub der Dosierpumpe die Entlüftung des Dosiersystems erleichtert. Wenn sich ein kompressibles Medium, wie Luft oder Dampf, im einem Förderraum der Dosierpumpe befindet, kann durch die zwangsweise Öffnung des ersten Rückschlagventils gewährleistet werden, dass die in dem Förderraum der Dosierpumpe befindliche Luft bzw. der Dampf ausgeschoben wird in die erste Leitung und dadurch ein Entlüften der Dosierpumpe stattfindet. Sobald nur noch flüssiges Reduktionsmittel in der Dosierpumpe vorhanden ist, fördert diese wieder voll und schiebt auch die in der Saugleitung vorhandenen Dampfblasen bzw. Luftblasen im Laufe der Zeit durch das Dosierventil aus dem Dosiersystem aus.Finally, the venting of the metering system is facilitated by the coupling of valve member and stroke of the metering pump. If a compressible medium, such as air or steam, is located in a delivery chamber of the metering pump, it can be ensured by the forced opening of the first check valve that the air or vapor in the delivery chamber of the metering pump is pushed out into the first conduit and thereby a venting of the metering takes place. As soon as only liquid reducing agent is present in the metering pump, this promotes full again and pushes the existing in the suction line vapor bubbles or air bubbles over time through the metering valve from the metering system.

Um ein sicheres Schließen und ein besseres Betriebsverhalten zu erreichen, ist weiter vorgesehen, dass das erste Rückschlagventil federbelastet ist.In order to achieve a safe closing and a better operating behavior, it is further provided that the first check valve is spring-loaded.

In weiterer vorteilhafter Ausgestaltung der Erfindung ist vorgesehen, dass in der Verbindungsleitung ein Druckhalteventil, insbesondere ein einstellbares Druckhalteventil, vorgesehen ist. Der Öffnungsdruck des Druckhalteventils wird so gewählt, dass er niedriger ist als der Öffnungsdruck des Dosierventils ist, da nur dann die Reflektion von Druckstößen sicher verhindert werden kann. Durch den Haltedruck des Druckhalteventils ist es aber möglich, die Dampfblasenbildung innerhalb der ersten Leitung bzw. des Dosiersystems zu unterdrücken und auch dadurch die Funktion und die Genauigkeit mit der das Reduktionsmittel eingedüst und dosiert wird, weiter zu verbessern.In a further advantageous embodiment of the invention, it is provided that in the connecting line, a pressure-holding valve, in particular an adjustable pressure-holding valve, is provided. The opening pressure of the pressure holding valve is chosen to be lower than the opening pressure of the metering valve, since only then can the reflection of pressure surges be reliably prevented. Due to the holding pressure of the pressure holding valve, it is possible to suppress the formation of vapor bubbles within the first conduit or of the metering system and thereby further improve the function and accuracy with which the reducing agent is injected and metered.

Weitere Vorteile und vorteilhafte Ausgestaltungen der Erfindung sind der nachfolgenden Zeichnung, deren Beschreibung und den Patentansprüchen entnehmbar. Alle in der Zeichnung, deren Beschreibung und den Patentansprüchen offenbarten Merkmale können sowohl einzeln als auch in beliebiger Kombination miteinander erfindungswesentlich sein.Further advantages and advantageous embodiments of the invention are the following drawings, the description and the claims removable. All of the features disclosed in the drawing, the description and the claims can be essential to the invention both individually and in any combination with one another.

Es zeigen:

Figur 1
den schematischen Aufbau eines erfindungsgemäßen Dosiersystems,
Figur 2
ein Dosiersystem und
Figur 3
ein Ausführungsbeispiel eines erfindungsgemäßen Dosiersystems.
Show it:
FIG. 1
the schematic structure of a metering system according to the invention,
FIG. 2
a dosing system and
FIG. 3
an embodiment of a metering system according to the invention.

In Figur 1 ist eine Brennkraftmaschine 1 mit einer Abgasnachbehandlungseinrichtung 3 stark vereinfacht und schematisch dargestellt. Die Abgasnachbehandlungseinrichtung 3 umfasst ein Abgasrohr 5, einen Oxidationskatalysator 7 und einen SCR-Katalysator 11. Die Strömungsrichtung des Abgases durch das Abgasrohr 5 ist durch Pfeile (ohne Bezugszeichen) angedeutet. Um den SCR-Katalysator 11 mit Reduktionsmittel zu versorgen, ist stromaufwärts des SCR-Katalysators 11 am Abgasrohr 5 ein Dosierventil 13 für das Reduktionsmittel angeordnet. Das Dosierventil 13 spritzt bei Bedarf Reduktionsmittel stromaufwärts des SCR-Katalysators 11 in das Abgasrohr 5 ein.In FIG. 1 is an internal combustion engine 1 with an exhaust aftertreatment device 3 greatly simplified and shown schematically. The exhaust gas aftertreatment device 3 comprises an exhaust gas pipe 5, an oxidation catalytic converter 7 and an SCR catalytic converter 11. The flow direction of the exhaust gas through the exhaust gas pipe 5 is indicated by arrows (without reference numerals). In order to supply the SCR catalytic converter 11 with reducing agent, a metering valve 13 for the reducing agent is arranged upstream of the SCR catalytic converter 11 on the exhaust gas pipe 5. The metering valve 13 injects reducing agent upstream of the SCR catalyst 11 into the exhaust pipe 5 as needed.

Das erfindungsgemäße Dosiersystem umfasst das Dosierventil 13, eine Dosierpumpe 15 sowie einen Speicherbehälter 17. Die Dosierpumpe 15 ist in Figur 1 nur als "black-box" dargestellt. Details hierzu werden nachfolgend anhand der Figuren 2 und 3 erläutert.The metering system according to the invention comprises the metering valve 13, a metering pump 15 and a storage tank 17. The metering pump 15 is in FIG. 1 only shown as "black box". Details are given below with reference to Figures 2 and 3 explained.

Zwischen der Dosierpumpe 15 und dem Dosierventil 13 ist eine erste Leitung 19 vorgesehen. Zwischen dem Tank 17 und der Dosierpumpe 15 ist eine zweite Leitung 21 vorgesehen.Between the metering pump 15 and the metering valve 13, a first line 19 is provided. Between the tank 17 and the metering pump 15, a second conduit 21 is provided.

Der Vollständigkeit halber sei noch auf die in der Abgasanlage angeordneten Sensoren, nämlich einen NOX-Sensor 25, sowie Temperatur-Sensoren 23 und 27 hingewiesen. Diese Sensoren 23, 25 und 27 sind über Signalleitungen (ohne Bezugszeichen) mit einem Steuergerät 29 der Brennkraftmaschine verbunden. Dieses Steuergerät 29 steuert die Brennkraftmaschine 1 und unter anderem auch die Dosierpumpe 15. Die Leitungsverbindung zwischen dem Steuergerät 29 und der Dosierpumpe 15 ist durch einen gestrichelten Pfeil (ohne Bezugszeichen) in Figur 1 dargestellt.For the sake of completeness, reference should still be made to the sensors arranged in the exhaust system, namely an NOX sensor 25 and temperature sensors 23 and 27. These sensors 23, 25 and 27 are connected via signal lines (without reference numeral) to a control unit 29 of the internal combustion engine. This control unit 29 controls the internal combustion engine 1 and among other things, the metering pump 15. The line connection between the control unit 29 and the metering pump 15 is indicated by a dashed arrow (without reference numeral) in FIG. 1 shown.

Anhand der Figur 2 wird ein Dosiersystem dargestellt und erläutert. Gleiche Bauteile werden mit den gleichen Bezugszeichen versehen und das als bezüglich der Figur 1 gesagte entsprechend. Das Dosierventil 13 ist als federbelastetes Ventil schematisch dargestellt.Based on FIG. 2 a dosing system is shown and explained. The same components are provided with the same reference numerals and as with respect to the FIG. 1 said accordingly. The metering valve 13 is shown schematically as a spring-loaded valve.

Die Dosierpumpe 15 ist als Membranpumpe mit einer Membran 31 ausgebildet. Die Membran 31 der Dosierpumpe 15 wird von einem Elektromagneten, umfassend eine Spule 33 und einen Anker 35, betätigt. Wenn die Spule 33 bestromt wird, bewegt sich der Anker 35 und mit ihm die Membran 31 in Figur 2 nach oben und führt einen Förderhub aus. Der Hub H ist in Figur 2 dargestellt. Die in Figur 2 dargestellte Ruheposition der Membran 31 und des Ankers 35 entspricht einem Hub H = 0.The metering pump 15 is designed as a diaphragm pump with a membrane 31. The diaphragm 31 of the metering pump 15 is actuated by an electromagnet comprising a coil 33 and an armature 35. When the coil 33 is energized, the armature 35 and with it the membrane 31 moves in FIG. 2 up and performs a delivery stroke. The stroke H is in FIG. 2 shown. In the FIG. 2 illustrated rest position of the diaphragm 31 and the armature 35 corresponds to a stroke H = 0.

Zwischen einem Förderraum 37 der Dosierpumpe 15 und der ersten Leitung 19 ist ein erstes Rückschlagventil 39 angeordnet. Das erste Rückschlagventil 39 ist in Figur 2 als Flatterventil umfassend ein Ventilglied 41 und einen Ventilsitz 43 dargestellt. Bei diesen Flatterventilen ist das Ventilglied 41 als elastische Membran aus einem Kunststoff, wie zum Beispiel EPDM, oder Metall ausgebildet. Eine Feder 44 übt eine Kraft in Schließrichtung des ersten Rückschlagventils 39 auf das Ventilglied 41 aus.Between a delivery chamber 37 of the metering pump 15 and the first line 19, a first check valve 39 is arranged. The first check valve 39 is in FIG. 2 shown as a flutter valve comprising a valve member 41 and a valve seat 43. In these flutter valves, the valve member 41 is formed as an elastic membrane of a plastic, such as EPDM, or metal. A spring 44 exerts a force in the closing direction of the first check valve 39 on the valve member 41.

Die Hubbewegung der Membran 31 wird über einen Stößel 45 teilweise auf das Ventilglied 41 übertragen. Dies geschieht dadurch, dass in der Ruheposition der Membran 31 und bei geschlossenem ersten Rückschlagventil 39 der Stößel 45 nicht auf der Membran 31 aufliegt.The lifting movement of the diaphragm 31 is partially transmitted to the valve member 41 via a plunger 45. This happens because in the rest position of the membrane 31 and when the first check valve 39 is closed, the plunger 45 does not rest on the membrane 31.

Zwischen dem der Membran 31 zugewandten Ende des Stößels 45 und der Membran 31 ist in diesem Zustand ein Abstand HMIN. Sobald der Hub H größer HMIN ist, hebt die Membran mit Hilfe des Stößels 45 das Ventilglied 41 vom Ventilsitz 43 ab. Diese Kopplung des Ventilglieds 41 mit dem Hub H der Membran 31 der Dosierpumpe führt dazu, dass das erste Rückschlagventil 39, unabhängig von den Druckverhältnissen in der ersten Leitung 19 und im Förderraum 37 während des Saughubs noch lang geöffnet bleibt. Infolge dessen wird durch die Saugbewegung der Membran 31 ein Teil des in der ersten Leitung 19 befindlichen Reduktionsmittels wieder in den Förderraum 37 zurückgesaugt. Dadurch findet ein Druckabbau in der Leitung 19 statt und das Dosierventil 13 schließt rasch und dicht.Between the diaphragm 31 facing the end of the plunger 45 and the diaphragm 31 is in this state, a distance HMIN. As soon as the stroke H is greater than HMIN, the membrane lifts the valve member 41 away from the valve seat 43 with the aid of the plunger 45. This coupling of the valve member 41 with the stroke H of the diaphragm 31 of the metering pump causes the first check valve 39, regardless of the pressure conditions in the first conduit 19 and in the delivery chamber 37 during the intake stroke remains open long. As a result, a portion of the reducing agent located in the first line 19 is sucked back into the delivery chamber 37 by the suction movement of the diaphragm 31. As a result, a pressure reduction takes place in the line 19 and the metering valve 13 closes quickly and tightly.

Zwischen dem Förderraum 37 und der zweiten Leitung 21 ist ein zweites Rückschlagventil 46 angeordnet, welches verhindert, dass während des Förderhubs der Dosierpumpe 15 Reduktionsmittel aus dem Förderraum 37 in die zweite Leitung 21 und den Tank 17 zurückströmen kann. Dieses zweite Rückschlagventil 46 ist in aller Regel nicht federbelastet. Es wird ebenfalls häufig als Flatterventil ausgebildet, obwohl es in Figur 2 und 3 symbolisch als Kugelventil dargestellt ist.Between the delivery chamber 37 and the second line 21, a second check valve 46 is arranged, which prevents 15 reducing agent from the delivery chamber 37 in the second conduit 21 and the tank 17 can flow back during the delivery stroke of the metering pump. This second check valve 46 is not spring-loaded as a rule. It will too often designed as a flutter valve, although it is in FIG. 2 and 3 symbolically represented as a ball valve.

In Figur 3 ist ein Ausführungsbeispiel eines erfindungsgemäßen Dosiersystems dargestellt. Bei diesem Ausführungsbeispiel ist das erste Rückschlagventil 39 als doppeltwirkendes Rückschlagventil ausgebildet und symbolisch als Kugelventil dargestellt, obwohl es sich auch hier in aller Regel um ein Flatter- oder Schnüffelventil handelt. Das erste Rückschlagventil 39 weist nicht nur den ersten Ventilsitz 43 auf, sondern auch noch einen zweiten Ventilsitz 47, dessen Ausgang über eine Verbindungsleitung 49 und die zweite Leitung 21 mit dem Tank 17 hydraulisch in Verbindung steht. Sobald die Dosierpumpe 15 mit der Förderung von Reduktionsmittel beginnt, steigt der Druck im Förderraum 37 über den in der ersten Leitung 19 herrschenden Druck an. Infolge dessen hebt das Ventilglied 41 vom ersten Ventilsitz 43 ab und verschließt die Verbindungsleitung 49, weil es dichtend auf den zweiten Ventilsitz 47 gepresst wird. Gleichzeitig wird dadurch die hydraulische Verbindung zwischen Förderraum 37 und erster Leitung 19 freigegeben und die Förderung von reduktionsmittel in die erste Leitung 19 beginnt. Der Förderhub läuft bei dem zweiten Ausführungsbeispiel genauso ab, wie anhand des ersten Ausführungsbeispiel gemäß Figur 2 erläutert.In FIG. 3 an embodiment of a metering system according to the invention is shown. In this embodiment, the first check valve 39 is formed as a double-acting check valve and shown symbolically as a ball valve, although it is also usually a flutter or sniffer valve. The first check valve 39 has not only the first valve seat 43, but also a second valve seat 47, the output of which is hydraulically connected to the tank 17 via a connecting line 49 and the second line 21. As soon as the metering pump 15 starts to deliver reducing agent, the pressure in the delivery chamber 37 rises above the pressure prevailing in the first line 19. As a result, the valve member 41 lifts off from the first valve seat 43 and closes the connection line 49 because it is sealingly pressed onto the second valve seat 47. At the same time thereby the hydraulic connection between the delivery chamber 37 and the first line 19 is released and the promotion of reducing agent in the first line 19 begins. The delivery stroke is the same in the second embodiment, as in the first embodiment according to FIG. 2 explained.

Wenn nun die Förderung beendet wurde und die Membran 31 wieder in ihre Ausgangslage zurückkehrt, sorgen die Druckverhältnisse im ersten Rückschlagventil 39 dafür, dass das Ventilglied 41 wieder gegen den ersten Ventilsitz 43 gepresst wird und dadurch die hydraulische Verbindung zwischen Förderraum 37 und erster Leitung 19 unterbrochen wird. Gleichzeitig wird eine hydraulische Verbindung zwischen erster Leitung 19, Verbindungsleitung 49, zweiter Leitung 21 und Tank 17 geöffnet, sodass eventuell von dem Dosierventil 13 ausgehende Druckstöße in den Tank 17 laufen und dort dissipiert werden.Now, when the promotion has ended and the membrane 31 returns to its original position, the pressure conditions in the first check valve 39 ensure that the valve member 41 is pressed against the first valve seat 43 and thereby interrupted the hydraulic connection between the pumping chamber 37 and the first line 19 becomes. At the same time, a hydraulic connection between the first line 19, connecting line 49, second line 21 and tank 17 is opened, so that possibly run out of the metering valve 13 pressure surges run into the tank 17 and are dissipated there.

Optional ist in der Verbindungsleitung 49 ein Druckhalteventil 51 vorgesehen. Das Druckhalteventil 51 dient dazu, einen einstellbaren Mindestdruck in der ersten Leitung 19 aufrechtzuerhalten, sodass der Siedepunkt des Reduktionsmittels in der ersten Leitung 19 erhöht und die Bildung von Dampfblasen unterdrückt wird. Vorteilhafterweise ist der Öffnungsdruck des Druckhalteventils 49 niedriger als der Öffnungsdruck des Dosierventils 13, sodass die Schließbewegung und das Abdichten des Dosierventils 13 durch das Druckhalteventil 51 nicht verhindert werden. Außerdem können dadurch Druckstöße, deren Amplitude höher ist als der Öffnungsdruck des Druckhalteventils 51 nahezu ungehindert in den Tank 17 weiterlaufen und dort dissipiert werden.Optionally, a pressure-maintaining valve 51 is provided in the connecting line 49. The pressure holding valve 51 serves to maintain a minimum settable pressure in the first conduit 19 so that the boiling point of the reducing agent in the first conduit 19 is increased and the formation of vapor bubbles is suppressed. Advantageously, the opening pressure of the pressure holding valve 49 is lower than the opening pressure of the metering valve 13, so that the closing movement and the sealing of the metering valve 13 are not prevented by the pressure-holding valve 51. In addition, this pressure surges whose amplitude is higher than the opening pressure of the pressure holding valve 51 continue to flow almost unhindered in the tank 17 and are dissipated there.

In besonders vorteilhafter Ausgestaltung der Erfindung ist das Druckhalteventil 51 bezüglich seines Haltedrucks einstellbar, sodass es entsprechend den herrschenden Betriebsbedingungen eingestellt werden kann. Dadurch ist es möglich, beispielsweise nach dem Abstellen der Brennkraftmaschine den Haltedruck zu verändern, sodass die ersteIn a particularly advantageous embodiment of the invention, the pressure holding valve 51 is adjustable with respect to its holding pressure, so that it can be adjusted according to the prevailing operating conditions. This makes it possible, for example, after stopping the engine to change the holding pressure, so that the first

Leitung 19 vollständig druckentlastet wird und dadurch das Dosierventil 13 auch über einen längeren Zeitraum vollständig dicht ist. Wenn die Gefahr der Dampfblasenbildung während des Betriebs der Brennkraftmaschine auftritt, kann der Haltedruck des Druckhalteventils 51 entsprechend erhöht werden.Line 19 is completely relieved of pressure and thereby the metering valve 13 is completely sealed even over a longer period. If the risk of vapor bubble formation occurs during the operation of the internal combustion engine, the holding pressure of the pressure holding valve 51 can be increased accordingly.

In Figur 3b ist ein Blockschaltbild des Ausführungsbeispiels gemäß Figur 3a dargestellt. Zusätzlich sind noch verschiedene Drucksensoren 53.1, 53.2 und 53.3 dargestellt, die je nach Bedarf installiert und mit dem Steuergerät 29 verbunden werden.In FIG. 3b is a block diagram of the embodiment according to FIG. 3a shown. In addition, various pressure sensors 53.1, 53.2 and 53.3 are shown, which are installed as required and connected to the control unit 29.

Claims (9)

  1. Dosing system for a liquid medium, in particular a liquid reducing agent, such as for example an aqueous urea-water solution (HWL), having a tank (17), having a dosing pump (15) and having a dosing valve (13), wherein a pressure side of the dosing pump (15) and the dosing valve (13) are connected to one another by a first line (19) and wherein the tank (17) and a suction side of the dosing pump (15) are connected to one another by a second line (21), characterized in that a first check valve (39) is provided in the first line (19), wherein the first check valve (39) is designed as a double-acting check valve, and wherein a second valve seat (47) of the first check valve (39) is hydraulically connected to the tank (17) or to the suction side of the dosing pump (15) via a connecting line (49).
  2. Dosing system according to Claim 1, characterized in that a stroke movement of the dosing pump (15) is transmitted at least partially to the valve element (41) of the first check valve (39).
  3. Dosing system according to Claim 2, characterized in that the dosing pump comprises a diaphragm (31) and in that the stroke movement (H) of the diaphragm (31) is transmitted at least partially to the valve element (41) of the first check valve (39).
  4. Dosing system according to Claim 3, characterized in that the valve element (41) of the first check valve (39) is lifted from a first valve seat (43) when the stroke movement of the dosing pump (15) exceeds a minimum stroke (Hmin).
  5. Dosing system according to one of the preceding claims, characterized in that the first check valve (39) is spring-loaded.
  6. Dosing system according to Claim 5, characterized in that a pressure-maintaining valve, in particular an adjustable pressure-maintaining valve (51), is provided in the connecting line (49).
  7. Dosing system according to one of the preceding claims, characterized in that a second check valve (46) is provided in the second line (21).
  8. Dosing system according to one of the preceding claims, characterized in that the dosing valve (13) is actuated by pressure.
  9. Dosing system according to Claim 3, characterized in that the diaphragm pump (15) is actuated by a control element of an actuator, in particular by an armature (35) of an electromagnet (33).
EP09765665A 2008-06-17 2009-04-22 Dosing system for a liquid medium, particularly a urea-water solution Not-in-force EP2294294B1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE102008002467A DE102008002467A1 (en) 2008-06-17 2008-06-17 Dosing system for a liquid medium, in particular urea-water solution
PCT/EP2009/054799 WO2009153085A1 (en) 2008-06-17 2009-04-22 Dosing system for a liquid medium, particularly a urea-water solution

Publications (2)

Publication Number Publication Date
EP2294294A1 EP2294294A1 (en) 2011-03-16
EP2294294B1 true EP2294294B1 (en) 2012-02-22

Family

ID=40886826

Family Applications (1)

Application Number Title Priority Date Filing Date
EP09765665A Not-in-force EP2294294B1 (en) 2008-06-17 2009-04-22 Dosing system for a liquid medium, particularly a urea-water solution

Country Status (6)

Country Link
US (1) US20110186153A1 (en)
EP (1) EP2294294B1 (en)
CN (1) CN102066709A (en)
AT (1) ATE546622T1 (en)
DE (1) DE102008002467A1 (en)
WO (1) WO2009153085A1 (en)

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE102010030860A1 (en) * 2010-07-02 2012-01-05 Robert Bosch Gmbh Method for operating reducing agent dosing system for selective catalytic reduction catalyst-converter in exhaust line of combustion engine of motor car, involves actuating metering valve for dosing certain dosage amount into exhaust line
DE102013101573A1 (en) * 2013-02-18 2014-08-21 Emitec France S.A.S Method for heating a conveyor
DE102018217305B4 (en) * 2018-10-10 2024-04-25 Vitesco Technologies GmbH Method for controlling a return valve and exhaust system

Family Cites Families (14)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2456566A (en) * 1946-11-18 1948-12-14 Shell Dev Reverse flow by-pass valve
US3805825A (en) * 1972-02-22 1974-04-23 Steinen Mfg Co Unitary pneumatic flow director
DE3380036D1 (en) * 1982-12-13 1989-07-13 Mikuni Kogyo Kk Method for controlling an air flow quantity
US5031661A (en) * 1988-07-08 1991-07-16 Buckner, Inc. Double check valve backflow preventer assembly
GB2260595B (en) * 1991-10-17 1995-05-31 Dowty Aerospace Gloucester A pressure relief valve
DE19631287B4 (en) * 1996-08-02 2004-01-15 Robert Bosch Gmbh Fuel pump device for two-stroke engines with an additional drive unit
DE19806265C5 (en) * 1998-02-16 2004-07-22 Siemens Ag dosing
DE19819579C1 (en) * 1998-04-30 1999-09-30 Siemens Ag Secondary treatment of exhaust from lean burn diesel engine with SCR catalyst, minimizing pump usage and energy consumption
DE10116214A1 (en) 2001-03-30 2002-10-10 Bosch Gmbh Robert Device for the aftertreatment of exhaust gases from an internal combustion engine
WO2005024232A1 (en) * 2003-09-02 2005-03-17 Hydraulik-Ring Gmbh Pump for conveying an exhaust gas aftertreatment medium, particularly a urea-water solution, for diesel engines
DE102004011123A1 (en) * 2003-09-02 2005-03-31 Hydraulik-Ring Gmbh Pump for conveying an exhaust aftertreatment medium, in particular a urea-water solution, for diesel engines
DE102004050023A1 (en) * 2004-10-13 2006-04-27 L'orange Gmbh Device for the metered injection of a reducing agent into the exhaust gas tract of an internal combustion engine
DE102006012855A1 (en) 2006-03-21 2007-09-27 Robert Bosch Gmbh Process and dosing system for pollutant reduction in automotive exhaust gases
DE102006045448A1 (en) * 2006-09-19 2008-03-27 Lechler Gmbh Check valve for injection device i.e. field syringe, has valve body designed and arranged in housing such that contact surface aligned in its position closing for free cross-section is null for counter pressure in counter pressure area

Also Published As

Publication number Publication date
US20110186153A1 (en) 2011-08-04
ATE546622T1 (en) 2012-03-15
EP2294294A1 (en) 2011-03-16
WO2009153085A1 (en) 2009-12-23
CN102066709A (en) 2011-05-18
DE102008002467A1 (en) 2009-12-24

Similar Documents

Publication Publication Date Title
EP2748439B1 (en) Metering system for a liquid reducing agent
EP2157295B1 (en) Metering system for a fluid medium, in particular urea-water solution
EP2569522B1 (en) Device for reducing pollutants in the exhaust gas flow of an internal combustion engine
EP2791480B1 (en) Dosing arrangement for a liquid exhaust gas after-treatment medium and dosing method
DE102016218497A1 (en) Reductant supply system for exhaust aftertreatment
EP2294294B1 (en) Dosing system for a liquid medium, particularly a urea-water solution
DE102012209689A1 (en) Device for ventilating exhaust gas after treatment system of motor car, has valve provided in closed position during engine idle condition, and shifted between passage- and closed positions by hydraulic actuatable actuator
EP3325782B1 (en) Injection valve, exhaust-gas aftertreatment system
EP2839154B1 (en) Dosing device
DE102010031651A1 (en) Device for dosing i.e. aqueous urea solution, into selective catalytic reduction catalyst in exhaust gas region of combustion engine in motor car, has stop valve arranged upstream to dosing valve and controllable by signal of control device
DE102013218552A1 (en) Method for operating a hydraulic conveying and dosing system
DE102011090070A1 (en) Exhaust gas treatment device for selective catalytic reduction of nitrogen oxides contained in exhaust gases of engine, has shut-off valve arranged in pressure line between feed pump and metering unit
EP2729674A2 (en) Dosing system and 3/2 directional valve for a dosing system
EP2603680B1 (en) Injection device for introducing a urea solution into the exhaust tract of an internal combustion engine
WO2012150103A1 (en) Pump device for a metering system
KR101719403B1 (en) Method for operating a metering apparatus
EP2864602A1 (en) Metering system for introducing a reducing agent into an exhaust conduit of an internal combustion engine
EP3020936B1 (en) Exhaust gas after-treating device for an internal combustion engine
DE102012106205A1 (en) Metering system for metering of liquid mediums, has metering valve, which is formed as hydraulically-opening nozzle, where pump and metering valve are directly connected with each other
DE102011078852A1 (en) Dosing unit for introducing reducing agent into exhaust gas flow of combustion engine of motor vehicle, comprises conveying module and nozzle that is open outwards, where nozzle has nozzle body with recess, and nozzle-needle
DE102013223908A1 (en) diaphragm pump
DE102019219636A1 (en) Method for operating a fluid supply system and fluid supply system
DE102014226478A1 (en) Shut-off valve for a dosing system and method for the diagnosis of a dosing valve of the dosing system
DE102014226476A1 (en) Shut-off valve for a dosing module and method for its diagnosis
DE102012223006A1 (en) Method for operation of dosing module of diesel engined motor car, involves operating pump device by actuation of electromagnet, and again-actuating electromagnet before closing valve device opened by previous pumping stroke

Legal Events

Date Code Title Description
PUAI Public reference made under article 153(3) epc to a published international application that has entered the european phase

Free format text: ORIGINAL CODE: 0009012

17P Request for examination filed

Effective date: 20110117

AK Designated contracting states

Kind code of ref document: A1

Designated state(s): AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HR HU IE IS IT LI LT LU LV MC MK MT NL NO PL PT RO SE SI SK TR

AX Request for extension of the european patent

Extension state: AL BA RS

17Q First examination report despatched

Effective date: 20110726

DAX Request for extension of the european patent (deleted)
GRAP Despatch of communication of intention to grant a patent

Free format text: ORIGINAL CODE: EPIDOSNIGR1

GRAS Grant fee paid

Free format text: ORIGINAL CODE: EPIDOSNIGR3

GRAA (expected) grant

Free format text: ORIGINAL CODE: 0009210

AK Designated contracting states

Kind code of ref document: B1

Designated state(s): AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HR HU IE IS IT LI LT LU LV MC MK MT NL NO PL PT RO SE SI SK TR

REG Reference to a national code

Ref country code: GB

Ref legal event code: FG4D

Free format text: NOT ENGLISH

REG Reference to a national code

Ref country code: CH

Ref legal event code: EP

REG Reference to a national code

Ref country code: AT

Ref legal event code: REF

Ref document number: 546622

Country of ref document: AT

Kind code of ref document: T

Effective date: 20120315

REG Reference to a national code

Ref country code: IE

Ref legal event code: FG4D

Free format text: LANGUAGE OF EP DOCUMENT: GERMAN

REG Reference to a national code

Ref country code: DE

Ref legal event code: R096

Ref document number: 502009002860

Country of ref document: DE

Effective date: 20120412

REG Reference to a national code

Ref country code: NL

Ref legal event code: VDEP

Effective date: 20120222

LTIE Lt: invalidation of european patent or patent extension

Effective date: 20120222

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: NO

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20120522

Ref country code: HR

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20120222

Ref country code: NL

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20120222

Ref country code: IS

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20120622

Ref country code: LT

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20120222

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: LV

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20120222

Ref country code: GR

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20120523

Ref country code: PT

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20120622

Ref country code: FI

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20120222

REG Reference to a national code

Ref country code: IE

Ref legal event code: FD4D

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: CY

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20120222

BERE Be: lapsed

Owner name: ROBERT BOSCH G.M.B.H.

Effective date: 20120430

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: SE

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20120222

Ref country code: IE

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20120222

Ref country code: PL

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20120222

Ref country code: SI

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20120222

Ref country code: RO

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20120222

Ref country code: CZ

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20120222

Ref country code: EE

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20120222

Ref country code: DK

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20120222

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: MC

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20120430

Ref country code: IT

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20120222

Ref country code: SK

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20120222

PLBE No opposition filed within time limit

Free format text: ORIGINAL CODE: 0009261

STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: NO OPPOSITION FILED WITHIN TIME LIMIT

26N No opposition filed

Effective date: 20121123

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: BE

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20120430

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: MK

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20120222

REG Reference to a national code

Ref country code: DE

Ref legal event code: R097

Ref document number: 502009002860

Country of ref document: DE

Effective date: 20121123

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: ES

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20120602

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: MT

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20120222

Ref country code: BG

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20120522

REG Reference to a national code

Ref country code: CH

Ref legal event code: PL

GBPC Gb: european patent ceased through non-payment of renewal fee

Effective date: 20130422

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: LI

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20130430

Ref country code: CH

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20130430

Ref country code: GB

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20130422

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: TR

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20120222

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: LU

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20120422

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: HU

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20090422

REG Reference to a national code

Ref country code: AT

Ref legal event code: MM01

Ref document number: 546622

Country of ref document: AT

Kind code of ref document: T

Effective date: 20140422

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: AT

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20140422

REG Reference to a national code

Ref country code: FR

Ref legal event code: PLFP

Year of fee payment: 8

REG Reference to a national code

Ref country code: FR

Ref legal event code: PLFP

Year of fee payment: 9

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: DE

Payment date: 20170623

Year of fee payment: 9

REG Reference to a national code

Ref country code: FR

Ref legal event code: PLFP

Year of fee payment: 10

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: FR

Payment date: 20180424

Year of fee payment: 10

REG Reference to a national code

Ref country code: DE

Ref legal event code: R119

Ref document number: 502009002860

Country of ref document: DE

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: DE

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20181101

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: FR

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20190430