WO2013178384A1 - Système d'injection, pompe de dosage, dispositif de retraitement de gaz d'échappement, procédé - Google Patents

Système d'injection, pompe de dosage, dispositif de retraitement de gaz d'échappement, procédé Download PDF

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Publication number
WO2013178384A1
WO2013178384A1 PCT/EP2013/056991 EP2013056991W WO2013178384A1 WO 2013178384 A1 WO2013178384 A1 WO 2013178384A1 EP 2013056991 W EP2013056991 W EP 2013056991W WO 2013178384 A1 WO2013178384 A1 WO 2013178384A1
Authority
WO
WIPO (PCT)
Prior art keywords
injection system
valve
piston
connection
tank
Prior art date
Application number
PCT/EP2013/056991
Other languages
German (de)
English (en)
Inventor
Rainer Haeberer
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
Priority to CN201380028295.7A priority Critical patent/CN104350251A/zh
Priority to US14/403,793 priority patent/US20150184570A1/en
Priority to EP13715185.8A priority patent/EP2855866A1/fr
Publication of WO2013178384A1 publication Critical patent/WO2013178384A1/fr

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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
    • F01N3/24—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 constructional aspects of converting apparatus
    • 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
    • F01N3/2066—Selective catalytic reduction [SCR]
    • 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
    • F01N3/2066—Selective catalytic reduction [SCR]
    • F01N3/208—Control of selective catalytic reduction [SCR], e.g. dosing of reducing agent
    • 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
    • F01N2610/02—Adding substances to exhaust gases the substance being ammonia or urea
    • 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
    • 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
    • F01N2610/1453—Sprayers or atomisers; Arrangement thereof in the exhaust apparatus
    • 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
    • F01N2610/1466—Means for venting air out of conduits or tanks
    • 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
    • F01N2610/1486—Means to prevent the substance from freezing
    • 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
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02A—TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE
    • Y02A50/00—TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE in human health protection, e.g. against extreme weather
    • Y02A50/20—Air quality improvement or preservation, e.g. vehicle emission control or emission reduction by using catalytic converters
    • 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
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
    • Y02T10/00—Road transport of goods or passengers
    • Y02T10/10—Internal combustion engine [ICE] based vehicles
    • Y02T10/12—Improving ICE efficiencies
    • 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
    • Y10T137/8593—Systems
    • Y10T137/85978—With pump
    • Y10T137/85986—Pumped fluid control

Definitions

  • the invention relates to an injection system for the metered injection of a liquid, in particular for an exhaust aftertreatment device of a motor vehicle, with a tank for storing the liquid, with a metering valve, with an actuatable venting valve for input and / or discharge of gas into or out of the Injection system and with a metering pump, which is connected to the tank and with the metering valve to promote the liquid from the tank to the metering valve.
  • the invention relates to a corresponding metering pump and an exhaust aftertreatment system. Furthermore, the invention relates to a method for operating a corresponding injection system.
  • Injection systems, metering pumps, exhaust aftertreatment systems and methods for operating these are known from the prior art.
  • SCR Selective Catalytic Reduction
  • the liquid is conveyed by means of a metering pump from a tank to a metering valve, which is often designed as a passive or pressure-controlled injection valve.
  • the metering pump measures the Einspitzmenge and builds up in the connection to the injection valve to a pressure.
  • EP 2 151 559 B1 discloses an injection system of the type mentioned in the opening paragraph in which this problem is to be avoided by providing a venting valve between the metering pump and the metering valve for introducing and / or discharging gas into or out of the injection system is.
  • the injection system according to the invention with the features of claim 1 has the advantage that a reversal of a working direction of the metering pump is not necessary. For example, the braking and restarting in the opposite direction of a drive of the metering pump omitted. Instead, the metering pump is designed and integrated into the injection system such that with the simplest means the liquid is injected or gas is introduced or expelled into the injection system.
  • the metering pump is designed as a piston pump and has a piston movable axially between an upper and a lower dead center in a cylinder, which forms a pump space together with the cylinder, wherein the cylinder, assigned to the pump chamber, has a first connection, which is connected by a tank line to the tank, a second port, which is connected by a delivery line to the injection valve, and a third port which is connected by a vent line to the vent valve comprises.
  • the ventilation valve, the dosing module and the tank are thus each directly connected to the metering pump. Since the metering pump is designed as a piston pump, it can, depending on the switching state of the different
  • the second connection is formed in an end region of the cylinder facing the top dead center.
  • the second port is located in an area that has the maximum delivery volume of the
  • the second connection is arranged in the end region on an end face of the cylinder. This end face is then opposite a piston surface of the piston facing the pump chamber. This ensures that the largest possible amount of liquid is supplied by the piston pump at a stroke of the piston to the metering valve.
  • the third connection is formed in the end region of the cylinder facing the top dead center. Equally, the arrangement of the third port in the end region ensures that the piston pump sucks the largest possible amount of air when the piston moves from top dead center to bottom dead center and then inserts it into the injection system.
  • the third connection can also be arranged on the end face of the cylinder, which is preferably at least substantially pot-shaped. Preferably, however, the third connection is formed in a jacket wall of the cylinder.
  • the first connection-seen in the direction of movement of the piston-between the third connection and the bottom dead center of the piston on the jacket wall of the cylinder is formed.
  • the first port is thus at a height between the third port and the bottom dead center of the piston. This has the consequence that the piston is passed on the way from the bottom dead center to the top dead center at the first port, so that it loses its connection to the pump chamber.
  • the first connection forms together with the piston a slide valve, which is closed by the piston from a certain position between top and bottom dead center. When the piston moves to the bottom dead center with the vent valve closed, it sucks in fluid via the first port as soon as it has moved over it.
  • the ventilation valve is closed again and the liquid of the piston is conveyed out of the pump chamber to the dosing module, provided the ventilation valve is closed.
  • the ventilation valve is opened during the next cycle.
  • a gas for example ambient air or exhaust gas
  • the first connection is opened due to geometry later, so that initially in the pump room initially predominantly air.
  • the valve is closed again, so that the gas in the pump chamber is compressed in a subsequent movement of the piston in the direction of top dead center and forced into the first port, whereby the injection system tank side provided at least partially with gas and thus is ventilated.
  • the pressure in the pump chamber continues to increase until the metering valve, which is preferably designed as a pressure-controlled injection valve, opens due to the high pressure.
  • the dosing module side part of the injection system is vented with the gas or freed from liquid and ensures the Eisscherfestmaschine the entire injection system.
  • the first connection is likewise formed on the end face of the cylinder.
  • This has the advantage that a larger amount of gas for aerating the injection system in the tank-side part of the injection system or in the tank line can be promoted, since the entire piston stroke is available.
  • the first connection is then associated with an automatic suction valve that opens when the piston moves in the direction of bottom dead center and at least substantially closes when the piston moves in the direction of top dead center.
  • the suction valve is designed as a spring-loaded check valve.
  • check valves are commodities and therefore cost.
  • the piston stroke of the piston pump can be shortened and a corresponding, for example, electric drive of the piston pump can be made smaller.
  • the suction valve is preferably designed such that it does not completely close in the compression stroke, ie when the piston moves from the bottom dead center to the top dead center, when there is air in the pump chamber or a ventilation process takes place.
  • the metering pump can perform so many strokes until the line and the metering pump are emptied to the tank. If, on the other hand, there is fluid in the pump chamber, ie during normal operation of the injection system, the suction valve remains closed.
  • the suction valve is designed as a diaphragm valve instead of a spring-loaded check valve.
  • Its membrane is suitably made of an elastomer material.
  • the membrane preferably has a sealing frame, which is connected via radially extending webs to a centrally arranged valve plate, in particular integrally formed.
  • the membrane is preferably designed so that it completely closes the first port in a liquid pumping operation and not in a gas pumping operation.
  • the suction valve is designed as a piston valve with integrated throttle.
  • the piston valve with integrated throttle works in a similar way to the diaphragm valve, depending on which medium is being pumped. If a gas is pumped, the piston valve does not close the first connection or at least not completely. By contrast, when fluid is delivered, the piston valve closes the fluid first connection completely, so that the liquid can not be conveyed back into the tank, a pressure builds up in the pump chamber, which opens the metering valve if necessary.
  • the ventilation valve is connected to a gas connection, which is designed in particular as an ambient air connection, connected to an exhaust pipe of the motor vehicle as an exhaust pipe connection or connected to the tank as a ventilation connection.
  • a gas connection which is designed in particular as an ambient air connection
  • an exhaust pipe of the motor vehicle as an exhaust pipe connection or connected to the tank as a ventilation connection.
  • At least one hydrophobic membrane is interposed between the ventilation valve and the gas connection.
  • the hydrophobic membrane on the one hand represents a simple throttle and thus prevents the air from the system can escape unhindered to the outside.
  • the hydrophobic membrane is associated with at least one store for liquid or gaseous medium. Since the hydrophobic membrane on the one hand has a small throttling effect, the accumulator can on the one hand take the form of an air reservoir and receive excess air or gas. On the other hand, the memory can absorb small amounts of filtered through the hydrophobic membrane from the air flow liquid, which thereby hinder the hydrophobic membrane is not in their air permeability. It is particularly advantageous if a respective store is provided on both sides of the hydrophobic membrane.
  • the reservoir may be formed, for example, as an elastically deformable piece of tubing, so that its volume adapts to the amount of excess air or liquid.
  • the metering pump according to the invention with the features of claim 13 has the advantage that it does not have to be driven in different directions in order to move from a normal operation of an injection system into a ventilation system. drove to switch.
  • the metering pump is designed as a piston pump and has a, in a cylinder axially movable between an upper and a lower dead center piston, which forms a pump space together with the cylinder, the cylinder associated with the pump chamber a first connection for one with a Tank of the injection system connectable tank line, a second connection for a connectable to the injection valve of the injection system pressure line and a third connection for a connectable to a ventilation valve vent line of the injection system.
  • the exhaust aftertreatment system according to the invention with the features of claim 14 is characterized by an injection system, as described above from. This results in the already mentioned advantages.
  • the inventive method for operating the injection system with the features of claim 15 is characterized by the fact that to switch from a liquid-promoting normal operation in a ice pressure-resistant state of the piston at least substantially continue to operate as in normal operation and depending on the position of the piston, the vent valve and so on it is concluded that a gas is introduced into the injection system.
  • An electric drive driving the piston for example, is thus not influenced in its working direction, which, as already described above, leads to advantages with respect to the dimensioning and also with respect to the speed of the switching. Only by operating the ventilation valve can be done a ventilation of the injection system. Further advantages and features emerge from the previously described embodiments.
  • FIG. 1 shows a first embodiment of an exhaust gas aftertreatment device for a motor vehicle with an injection system
  • FIG. 2 shows a second exemplary embodiment of the exhaust gas aftertreatment device
  • Figure 3 shows an advantageous development of the exhaust aftertreatment device
  • Figures 4A and 4B a first alternative embodiment of a suction valve of the injection system and
  • Figure 5 shows a second alternative embodiment of the suction valve.
  • FIG. 1 shows, in a simplified illustration, an exhaust gas aftertreatment device 1 for a motor vehicle, which is not shown here in greater detail.
  • the exhaust gas aftertreatment device has an injection system 2.
  • the injection system 2 has a tank 3, which serves for the storage of the liquid exhaust gas after-treatment means 4.
  • the tank 3 is largely filled, with an air buffer 5 remains therein.
  • the tank 3 is connected to a metering pump 7.
  • the metering pump 7 is designed as a piston pump 8 and has for this purpose a substantially cup-shaped cylinder 9, in which axially a piston 10 is arranged to be displaceable between an upper and a lower dead center.
  • the piston 10 is connected, for example, to a connecting rod, which displaces the piston 10 in an oscillating reciprocating motion, as indicated by a double arrow 11, by means of an example of an electric motor driven crankshaft.
  • the piston 10 forms together with the cylinder 9 a pump chamber 12 whose volume is changed by the movement of the piston 10.
  • the piston 10 is formed in this case as a solid-state piston and lies with its outer surface sealingly on the inner surface of the jacket wall 13 of the cylinder 9 at.
  • one or more sealing rings between the piston 10 and cylinder 9 may be provided.
  • the cylinder 9 On its jacket wall 13, the cylinder 9 has a first connection 14, which is connected to the tank line 6.
  • the port 14 opens into the pump chamber 12 of the piston pump 8 above or spaced from the bottom dead center of the piston 10, as shown in Figure 1.
  • a filter 15 is optionally between the tank 3 and the metering pump 7 as well as other components 16 interposed. At least one of the components 16 may be formed, for example, as a heater.
  • the metering pump 7 has a second connection 17, which is connected by a delivery line 18 to a metering valve 19.
  • the metering valve 19 is a
  • the injection valve 21 is designed as a spring-loaded injection valve 21.
  • an additional check valve 22 is interposed between the metering valve 19 and the second port 17.
  • the metering pump 7 has a third connection 23, which is connected by a ventilation line 24 to a ventilation valve 25.
  • the second connection 17 and the third connection 23 are both arranged or formed in an end region 26 of the cylinder 9 facing away from the piston 10.
  • the third connection 23 likewise opens through the jacket wall 13 into the pump chamber 12, the connection 17 is arranged on the closed or substantially closed end side 27 of the cup-shaped cylinder 9.
  • the first connection 14 thus lies axially between the bottom dead center of the piston 10 and the third connection 23.
  • the piston 10 In normal operation, that is, when the liquid exhaust aftertreatment agent 4 is to be admixed to the exhaust gas flowing through the exhaust pipe 20, the piston 10 traveling in the direction of bottom dead center sucks the exhaust aftertreatment agent 4 via the port 14 into the pump chamber 12. Subsequently, the piston 10 drives on its way in the direction of top dead center, the liquid through the port 17 in the delivery line 18 to the metering valve 19, which opens at sufficient pressure and the exhaust aftertreatment means 4 injected into the exhaust pipe 20.
  • the ventilation valve 25 is always closed.
  • the injection system 2 If the injection system 2 is switched off, its ice pressure resistance must be ensured. This means that it must be prevented at standstill of the injection system 2 that by an increase in volume of the exhaust aftertreatment agent 4 -when this freezes- the injection system 2 is damaged. To ensure the ice pressure resistance is provided, the injection system 2 at least substantially exempt from the liquid exhaust aftertreatment means 4 and to aerate. The procedure is as follows:
  • the vent valve 25 is opened.
  • the ventilation valve 25 is connected to a gas connection 27, which is designed, for example, as an ambient air connection. If the ventilation valve 25 is opened, it thus connects the pressure chamber 12 with the ambient air. By opening the vent valve 25 ambient air is thus sucked into the pump chamber 12 in a movement of the piston 10 in the direction of bottom dead center. Due to the low flow resistance of the gas or the ambient air, no negative pressure is built up in the piston chamber.
  • the gas connection 27 may also be formed as an exhaust pipe connection and thus be connected to the exhaust pipe.
  • the gas connection 27 may be formed as a tank connection, which is arranged on the tank 3 in the region of the air buffer 5.
  • the design of the gas connection 27 as a tank connection has the advantage that the air taken from the tank is optionally enriched with ammonia, so that when sucking in air or when venting the injection system 2 crystal formation is prevented in the system, which otherwise, for example, the function of the ventilation valve 25 could affect.
  • connection 14 Since the connection 14 opens below the connection 23 in the jacket wall of the cylinder 9 into the pump chamber 12, the connection 14, together with the piston 10, acts as a slide valve. As soon as the piston 10 has moved past the connection 14 in the direction of the bottom dead center, the connection 14 is released. As a result of the geometry of the connection 14, therefore, it is not opened until late, the gas or the ambient air is initially predominantly located in the pump chamber 12. This process is further assisted by the fact that the liquid exhaust aftertreatment agent, in contrast to the ambient air at the piston 10 which is moving in the direction of the bottom dead center, is throttled more strongly and has a higher inertia. The check valve 22 remains in its closed position and thus has no influence on the events in the pump chamber 12 reaches the piston 10 bottom dead center, the vent valve 25 is closed.
  • the air is forced into the port 14, as soon as the Piston 10 moves again in the direction of top dead center.
  • the liquid in the tank line 6 is pushed back in the direction of the tank 3. If the filter 15 is arranged close enough to the metering pump 7, the tank line 6 can be vented up to the filter 15 or freed from the liquid by a single stroke of the piston 10. Otherwise, this process is carried out until the tank line 6 is desired to be well ventilated.
  • the metering valve 19 is opened sooner or later by the compressed in the pump chamber 12 ambient air.
  • the liquid present in the delivery line 18 is forced into the exhaust pipe 20 and the delivery line 18 to the metering valve 19, and thereby also the metering valve 19 itself ventilated.
  • the piston 10 on its front side 17 facing piston surface 28 a chamfer 29, so that during a stroke movement of the piston 10, the gas can flow longer in the tank line 6 through the terminal 14 or is urged.
  • the injection system 2 If the injection system 2 is to be put back into operation, it must be vented or freed from the gas and filled with the exhaust gas aftertreatment agent 4. This is also possible in a simple manner by means of the present injection system 2. As soon as the piston 10 leaves the top dead center, the vent valve 25 is closed. Thus, a negative pressure is created in the pump chamber 12, which then sucks via the port 14 located in the injection system air. If the piston moves back from the bottom dead center in the direction of the top dead center, then the vent valve 25 is opened again and the air in the pump chamber 12 is conveyed through the connection 23 back into the environment.
  • Figure 2 shows another embodiment of the exhaust aftertreatment device 1 and the injection system 2.
  • Figure 1 elements are provided with the same reference numerals, so that in so far on the above description is referenced. In the following, essentially only the differences will be discussed.
  • the terminal 14 opens through the casing wall 13 in the pump chamber 12 and in the cylinder 9, it is according to the present embodiment ( Figure 2) arranged on the front side of the cylinder 9. Since the connection 14 can no longer interact with the piston 10 as a slide valve, the connection 14 is assigned a suction valve 30.
  • the suction valve 30 is formed as a spring-loaded check valve 31. If the piston 10 moves downwards, ie in the direction of the bottom dead center, the suction valve 30 opens automatically as soon as a certain negative pressure is present in the pump chamber 12. In normal operation, the vent valve 25 is closed. When descending piston 10, the check valve 22 closes due to the set on the metering valve 19 opening pressure.
  • the suction valve 30 opens due to the resulting negative pressure in the pump chamber 12.
  • the suction valve 30 may have a very soft spring.
  • the piston 10 reaches the bottom dead center and then begins a compression of the suctioned via the suction valve 30 liquid.
  • the suction valve 30 closes and the check valve 22 opens, so that the liquid is urged in the direction of the passive injection valve 21, which opens when its triggering pressure is exceeded and injects the exhaust gas aftertreatment agent into the exhaust pipe 20.
  • the vent valve 25 In the ventilation mode, the vent valve 25 is open during the downward movement of the piston 10, so that gas can flow into the pump chamber 12. Between suction valve 25 and tank 3 is a liquid column, beyond the vent valve 25 in principle an air column. As a result of the inertia of the liquid, and in particular its friction on the pipe wall of the respective pipe in the movement of the piston 10 in the direction of bottom dead center through the vent valve 25, the air, which has no friction on the pipe wall in contrast to the liquid, in the cylinder 10 or sucked into the pump chamber 12. By appropriate throttle tuning this behavior can be favored. Due to the dead volumes and the wall friction of the liquid or the liquid exhaust aftertreatment agent 4, it is advantageous if the ventilation 25 valve as close to the cylinder 9 is arranged.
  • the vent valve 25 closes until the piston 10 has reached its top dead center again.
  • the accumulated in the pump chamber 12 air is forced through the suction valve 30 into the injection system 12 in the direction of the tank 3 and in the tank line 6.
  • Suction valve 30 is designed such that it does not close or at least not completely in the air compression stroke, while in normal operation, when only liquid is in the pump chamber 12, completely closes. In this case, the check valve 22 and the injection valve 21 will also remain closed.
  • the metering pump 7 must perform a corresponding number of air strokes until the tank line 6 and the metering pump 7 are emptied to the tank 3.
  • the piston 10 is advantageously formed without the chamfer 29 in order to increase the efficiency of the metering pump 7.
  • a further filter 32 is also arranged in the tank 3, which is connected upstream of the tank line 6.
  • the present injection system 2 has the advantage that the full stroke of the piston 10 for sucking and injecting the liquid exhaust aftertreatment agent 4 as well as for driving gas into the tank line 6 and / or into the delivery line 18 can be used.
  • piston in the first exemplary embodiment according to FIG. 1 must be embodied as a solid-state piston, in the exemplary embodiment according to FIG. 2 it can also be designed as a membrane so that the metering pump 7 is designed as a piston pump 8 with a deformable piston or as a diaphragm pump , Only the training as a sliding valve with respect to the claim 14 is not possible by means of the diaphragm pump, so that such an embodiment would not or only with difficulty be implemented in the first embodiment.
  • FIG. 3 shows an advantageous development of the injection system 2 according to Figure 2.
  • this development may also be provided in the embodiment of Figure 1, however. Elements already known from the preceding figures are provided with the same reference numerals, so that reference is made to the description above.
  • the advantageous development in FIG. 3 relates to the gas connection 27. If gas is drawn in via the ventilation valve 25 from the exhaust gas or the surroundings during ventilation operation, pronounced crystal formation may occur at the seat of the ventilation valve 25 due to contact of ammonia from the exhaust aftertreatment agent with fresh air , In addition, when venting the
  • Injection system 2 with ammonia-enriched air are blown into the environment, which could lead to an unpleasant odor.
  • a hydrophobic membrane 32 is interposed between the gas connection 27 and the ventilation valve 25 in the present case.
  • the hydrophobic membrane 32 on the one hand represents a small throttle and thus prevents air or gas from the injection system 2 can escape unhindered to the outside.
  • each a memory 33 and 34 are provided, each forming a storage volume.
  • the memory 33 and 34 may be formed, for example, as elastic deformable hose pieces.
  • the memory 33, 34 act because the hydrophobic membrane 32 has a low
  • Throttling has, on the one hand as an air reservoir, and on the other hand, small amounts of liquid can be absorbed, whereby they do not affect the hydrophobic membrane 32 in their air permeability or hinder.
  • the hydrophobic membrane 32 is arranged directly at the bottom of the memory 33.
  • a line 35 leads from the hydrophobic membrane 32 to the memory 34. From this then leads a further line 36 to the vent valve 25, which is connected via the vent line 24 as described above with the dosing pump 7.
  • valve-side line 36 is connected to the memory 34 at the lowest possible level and the line 35 in the upper region of the memory 34.
  • the memory 33 which also forms the gas connection 27 at the same time, has a sieve 37 at its open or free end which has particularly small holes representing large chokes. Thus, can take place between the environment and the memory 33 only a small exchange of air.
  • the portion between the gas port 27 and the vent valve 25 forms a kind of dead-end, in which the air is held substantially in the reservoirs 33 and 34.
  • the memory 33, 34 have the advantage that air with high ammonia content can not get into the environment abruptly. Through the sieve 37 fresh air is sucked into the memory 33. If the venting of the injection system 2, for example, made in a garage, prevents the memory
  • ammoniacal air is blown into the environment.
  • the accumulator 34 contains air with a high ammonia concentration, which, however, will not escape into the accumulator 33 during normal operation due to the small throttling effect of the hydrophobic membrane 32.
  • the ammonia-rich air in the storage 34 is sucked into the injection system 2 and the low-ammonia air in the storage 33 reaches the storage 34. In return, fresh air is sucked into the memory 33 from the outside.
  • This storage arrangement with the hydrophobic membrane 32 is optionally also implemented on the tank side, so that the tank 3 has a hydrophobic ventilation membrane 38 in the region of the tank line 6.
  • the air buffer 5 forms a corresponding reservoir 39.
  • the hydrophobic ventilation membrane 38 is adjoined by an in particular long conduit 40 with an end screen 41, the conduit 40 forming a reservoir 42.
  • the tank-side storage device thus essentially corresponds to the ventilation Valve-side storage device. About the metering pump 7, the two storage devices communicate with each other.
  • the ammonia-added air is selectively reciprocated between the two storage devices and is conveyed or promoted, and that only the gas with low ammonia content of the memory 33 and 42 in small quantities in the Environment can reach.
  • the memory 33 could also be omitted, since in this case the exhaust pipe 20 acts as a memory.
  • the storage devices described can each also be provided in an injection system 2 with a metering pump according to the exemplary embodiment of FIG.
  • a metering pump according to the exemplary embodiment of FIG.
  • FIGS. 4 and 5 show alternative embodiments of the suction valve 14.
  • FIG. 4 shows the suction valve 14 as a diaphragm valve 43.
  • FIG. 4A shows a planar membrane 44 of the diaphragm valve 43 in a plan view, the diaphragm 44 having a continuous sealing frame 45 which is connected by webs 46 to a centrally arranged valve plate 47.
  • the valve plate 47, the webs 46 and the sealing frame 45 are integrally formed with each other.
  • the membrane 44 is made of an elastically deformable elastomer material.
  • FIG. 4B shows a longitudinal section of the diaphragm valve 43.
  • the diaphragm valve 43 has a connecting piece 48 facing the connection 14 and a connecting piece 49 assigned to the tank line 6.
  • the sockets 48 and 49 are aligned with each other and spaced from each other.
  • the membrane 44 extends transversely between the nozzle 48 and 49, wherein it rests sealingly in the initial state on the free end of the nozzle 48.
  • the sealing frame 45 is sealingly held in a housing forming or retaining the connecting pieces 48 and 49. Air or liquid can thus only pass through the membrane 44 past the webs 46 and the valve plate 47, from one nozzle to the other. long.
  • the liquid forms a pressure wave, which presses the valve plate 47 due to their pressure pulse sealingly against the free end of the nozzle 49, so that the pump chamber is sealed in the direction of the tank 3 and the Injection valve 21 opens due to the overpressure. Wrd compressed air, so there is no pronounced pressure wave.
  • the valve plate 47 rises only so far that air can penetrate past her and in the other port 49. The suction valve 14 is thus not closed in this case and the air can force the liquid exhaust aftertreatment agent 4 located in the tank line 6 back towards the tank 3.
  • Figure 5 shows an alternative embodiment of the suction valve 14, which is formed in this case as a piston valve 50 with integrated throttle.
  • the piston valve 50 has an axially displaceable piston 51, through which a channel 52 extends axially, which forms a throttle 53.
  • the piston 51 is in one
  • Receiving 54 out the diameter of which substantially corresponds to the diameter of the piston 41, so that it rests laterally sealing in the receptacle 54.
  • the receptacle 54 is axially slightly longer than the piston 51, so that the latter can move axially in the receptacle 54.
  • Into the receptacle 54 opens on one side of the terminal 14 and on the other side of the tank line
  • the opening of the port 14 is aligned with respect to the piston 51 such that the port 14 is in communication with the channel 52.
  • Piston valve 50 is closed.
  • the operation is similar to that of the diaphragm valve 43. If a pressure is built up in the pump chamber 12 during normal operation by a movement of the piston 10, the pressure wave through the fluid causes the piston 51 to be urged against the upper stop, thereby closing the channel 52 becomes. If, on the other hand, air is compressed in the pump chamber 12, it can flow through the channel 52 without the piston 51 being forced into the upper stop. As a result, the compressed air can pass through the channel 52 into the tank line 6 and push back there the liquid exhaust gas aftertreatment agent 4. When liquid is aspirated in normal operation, the piston 51 is urged against the lower stop, in which the channel 52 is always in communication with the port 14, so that the exhaust aftertreatment means 4 can always flow in the direction of the pump chamber 12.
  • vent valve 25 is opened only shortly after reaching the top dead center by the piston 10. This ensures that the piston 51 has safely left the top stop.
  • the opening or process of the piston in the lower stop could also be promoted by a compression spring, which is arranged for example in the receptacle 54 between the upper stop and the piston 51.
  • the vent valve 25 When the injection system 2 is to be vented again, the vent valve 25 is closed in a downward movement of the piston 10 in the direction of bottom dead center. In the subsequent upward movement of the piston 10, the valve 25 is opened and the air in the pump chamber 12 leaves the injection system 2 again via the vent valve 25 and enters the environment, in the tank 3 or in the exhaust pipe 20.
  • the throttle effect and the hydrostatic pressure in the direction of the tank 3 is so large that the air will not escape in the direction of the tank 3 through the port 14. If higher pressure loss beyond the ventilation valve 25 is to be expected, it would be advantageous if the previously described filter 32 is designed as a hydrophobic filter in the tank bottom.

Landscapes

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

Abstract

L'invention concerne un système d'injection (2) servant à injecter un liquide de manière dosée, destiné notamment à un dispositif de retraitement des gaz d'échappement (1) d'un véhicule automobile, comprenant : un réservoir (3) servant à emmagasiner le liquide; une vanne de dosage (19) munie d'un clapet d'aération (25) actionnable pour laisser entrer ou sortir du gaz dans ou hors du système d'injection (2); et une pompe de dosage (7) qui est reliée au réservoir (3) et à la vanne de dosage (19) pour transporter le liquide du réservoir (3) vers la vanne de dosage (19). Selon l'invention, la pompe de dosage (19) est réalisée sous la forme d'une pompe à piston (8) et présente un piston (10) qui peut se déplacer dans un cylindre (9) dans le sens axial entre un point mort haut et un point mort bas et qui forme avec le cylindre (9) un espace de pompe (12). Le cylindre (9) présente, associés à l'espace de pompe (12), un premier raccord (14) relié au réservoir (3) par le biais d'une conduite de réservoir (6), un deuxième raccord (17) relié à la vanne de dosage (19) par le biais d'une conduite de refoulement (18), et un troisième raccord (23) relié au clapet d'aération (25) par le biais d'une conduite d'aération (24). L'invention concerne également une pompe de dosage ainsi qu'un système de retraitement de gaz d'échappement. L'invention concerne en outre un procédé pour faire fonctionner un système d'injection correspondant.
PCT/EP2013/056991 2012-05-29 2013-04-03 Système d'injection, pompe de dosage, dispositif de retraitement de gaz d'échappement, procédé WO2013178384A1 (fr)

Priority Applications (3)

Application Number Priority Date Filing Date Title
CN201380028295.7A CN104350251A (zh) 2012-05-29 2013-04-03 喷射系统、配量泵、废气后处理装置、方法
US14/403,793 US20150184570A1 (en) 2012-05-29 2013-04-03 Injection system, metering pump, exhaust gas treatment device, method
EP13715185.8A EP2855866A1 (fr) 2012-05-29 2013-04-03 Système d'injection, pompe de dosage, dispositif de retraitement de gaz d'échappement, procédé

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE102012208933.0 2012-05-29
DE102012208933A DE102012208933A1 (de) 2012-05-29 2012-05-29 Einspritzsystem, Dosierpumpe, Abgasnachbehandlungseinrichtung, Verfahren

Publications (1)

Publication Number Publication Date
WO2013178384A1 true WO2013178384A1 (fr) 2013-12-05

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Country Link
US (1) US20150184570A1 (fr)
EP (1) EP2855866A1 (fr)
CN (1) CN104350251A (fr)
DE (1) DE102012208933A1 (fr)
WO (1) WO2013178384A1 (fr)

Cited By (2)

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EP3159508A1 (fr) * 2015-10-23 2017-04-26 Eberspächer Exhaust Technology GmbH & Co. KG Dispositif et procédé de distribution de réactif dans le flux de gaz d'échappement d'un moteur à combustion interne
US11815051B2 (en) * 2019-02-13 2023-11-14 Bayerische Motoren Werke Aktiengesellschaft Method for actuating a dosing valve, tank ventilation system, and motor vehicle

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CN106285851A (zh) * 2016-09-22 2017-01-04 凯龙高科技股份有限公司 一种计量泵用液路吹扫装置
DE102017201132A1 (de) * 2017-01-25 2018-07-26 Robert Bosch Gmbh Vorrichtung zur Einführung eines mehrere Adern oder Litzen umfassenden Elektrokabels in ein Gehäuse, Dosiermodul für eine Abgasnachbehandlungseinrichtung mit einer solchen Vorrichtung
CN108930573B (zh) * 2017-05-27 2021-11-30 罗伯特·博世有限公司 尿素水溶液进给系统和控制该系统中的压力波动的方法
IT201800004099A1 (it) * 2018-03-29 2019-09-29 Magneti Marelli Spa Pompa a pistoni e relativo metodo di controllo
WO2021131054A1 (fr) * 2019-12-27 2021-07-01 サンスター技研株式会社 Système d'alimentation en gaz, système de moussage mécanique et procédé d'alimentation en gaz
CN113009903B (zh) * 2021-02-22 2022-07-15 一汽解放汽车有限公司 一种故障诊断方法、装置、车辆及存储介质

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EP2151559B1 (fr) 2008-08-08 2011-04-06 Magneti Marelli S.p.A. Dispositif d'injection pour l'injection d'une substance réductrice dans un système d'échappement d'un moteur à combustion interne
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US11815051B2 (en) * 2019-02-13 2023-11-14 Bayerische Motoren Werke Aktiengesellschaft Method for actuating a dosing valve, tank ventilation system, and motor vehicle

Also Published As

Publication number Publication date
DE102012208933A1 (de) 2013-12-05
US20150184570A1 (en) 2015-07-02
CN104350251A (zh) 2015-02-11
EP2855866A1 (fr) 2015-04-08

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