US20150033712A1 - Method for draining a delivery unit for liquid additive, delivery unit and motor vehicle having a delivery unit - Google Patents

Method for draining a delivery unit for liquid additive, delivery unit and motor vehicle having a delivery unit Download PDF

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Publication number
US20150033712A1
US20150033712A1 US14/518,096 US201414518096A US2015033712A1 US 20150033712 A1 US20150033712 A1 US 20150033712A1 US 201414518096 A US201414518096 A US 201414518096A US 2015033712 A1 US2015033712 A1 US 2015033712A1
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United States
Prior art keywords
delivery unit
switch
draining
liquid additive
delivery
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.)
Abandoned
Application number
US14/518,096
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English (en)
Inventor
Carsten Kruse
Thomas Nagel
Sven Schepers
Jan Hodgson
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.)
Vitesco Technologies Lohmar Verwaltungs GmbH
Original Assignee
Emitec Gesellschaft fuer Emissionstechnologie mbH
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Filing date
Publication date
Application filed by Emitec Gesellschaft fuer Emissionstechnologie mbH filed Critical Emitec Gesellschaft fuer Emissionstechnologie mbH
Assigned to EMITEC GESELLSCHAFT FUER EMISSIONSTECHNOLOGIE MBH reassignment EMITEC GESELLSCHAFT FUER EMISSIONSTECHNOLOGIE MBH ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: SCHEPERS, SVEN, HODGSON, JAN, NAGEL, THOMAS, KRUSE, CARSTEN
Publication of US20150033712A1 publication Critical patent/US20150033712A1/en
Abandoned legal-status Critical Current

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    • 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
    • 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
    • F01N3/005—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for draining or otherwise eliminating condensates or moisture accumulating in the 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
    • 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
    • F01N2610/1486—Means to prevent the substance from freezing
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
    • H01H37/00—Thermally-actuated switches
    • H01H37/02—Details
    • H01H37/32—Thermally-sensitive members
    • H01H37/36—Thermally-sensitive members actuated due to expansion or contraction of a fluid with or without vaporisation
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
    • H01H37/00—Thermally-actuated switches
    • H01H37/02—Details
    • H01H37/32—Thermally-sensitive members
    • H01H37/46—Thermally-sensitive members actuated due to expansion or contraction of a solid
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
    • H01H37/00—Thermally-actuated switches
    • H01H37/02—Details
    • H01H37/32—Thermally-sensitive members
    • H01H37/52—Thermally-sensitive members actuated due to deflection of bimetallic element
    • 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
    • Y10T137/0318—Processes
    • Y10T137/0324—With control of flow by a condition or characteristic of a fluid
    • 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
    • Y10T137/1189—Freeze condition responsive safety systems

Definitions

  • the invention relates to a method for draining a delivery unit for liquid additive.
  • the invention also relates to a delivery unit and a motor vehicle having a delivery unit.
  • Such delivery units are used, for example, for delivering urea-water solution as liquid additive into the exhaust-gas treatment device of an internal combustion engine.
  • SCR selective catalytic reduction
  • a 32.5% urea-water solution which is available under the trademark AdBlue® is typically used.
  • a problem with such delivery units is the fact that the liquid additives can freeze during long standstill periods of the delivery units.
  • the described urea-water solution for example, freezes at ⁇ 11° C. Such low temperatures may arise, in particular, during long standstill phases of a motor vehicle in winter.
  • Water-based liquid additives in particular, (such as the urea-water solution) expand in terms of their volume as they freeze. That can damage the delivery unit. It is therefore known from the prior art to drain a delivery unit upon the cessation of operation of a motor vehicle.
  • the liquid additive which is located in the delivery unit is usually delivered back, during the draining process, into a tank in which the liquid additive is stored.
  • delivery unit wear which occurs as a result of the draining process is also problematic.
  • a pump of the delivery unit can be subject to increased wear as a result of the draining process.
  • a method for draining a delivery unit for liquid additive comprising at least the following steps:
  • the delivery unit that can be drained by using the described method preferably has at least one delivery line which extends from a tank for the liquid additive to a feed device (nozzle, injector, valve or the like) for the feed of the liquid additive to a consumer (for example an exhaust-gas treatment device).
  • the delivery line is connected to the tank at an extraction point so that liquid additive from the tank can enter the delivery line.
  • a pump which is preferably disposed in the delivery line, pumps the liquid additive through the delivery line.
  • the delivery line and the pump are filled with liquid additive during the delivery operation of the delivery unit.
  • the delivery unit may have further components filled with liquid additive.
  • the method is implemented specifically when the delivery unit and/or the motor vehicle are/is deactivated, that is to say, for example, no ignition is applied or the engine is inactive.
  • the method may thus be activated, for example, when the motor vehicle is deactivated.
  • the switch used in step a) is preferably distinguished in that the operation thereof does not require any current before the electrical connection has been produced. It is preferable if, in the switch, a mechanical and/or physical effect is utilized which produces the electrical connection. The thermal expansion of a material or phase changes of a material may be specified as examples for correspondingly utilizable mechanical and/or physical effects.
  • the switch is thus in a currentless standby position before step a).
  • the switch is referred to in step a) as a currentless switch. This also means, in particular, that the switch is not actuated by an electrical connection. There is, in particular, no electrical actuation line through which an electrical signal can arrive at the switch in order to control the position of the switch.
  • the switch is preferably configured in such a way that it produces the electrical connection when a temperature in the surroundings of the switch reaches or drops below a (lower) threshold temperature.
  • This threshold temperature is typically above a freezing temperature of the liquid additive being used.
  • the threshold temperature is determined by the structure of the switch.
  • the switch can interact with the delivery unit and/or is part of the delivery unit itself. If the delivery unit is integrated into a motor vehicle, the switch can, where appropriate, then also be provided at a position which is disposed remotely from the delivery unit. The position of the switch should be selected, in particular, in such a way that with the switch it is possible to acquire or predict information which is characteristic of the current aggregate state of the additive.
  • the delivery unit has, in particular, a detection device with which the current state of the switch can be detected, in particular it can be detected whether the latter is currentless or energized.
  • switches which can then make available information on the ambient temperature and/or the aggregate state of the additive for, for example, different sections of the delivery unit.
  • the information which is acquired with a plurality of switches can be used to define when partial/complete draining is to be initiated or carried out.
  • At least a (significant) part of the liquid additive, but preferably all of the liquid additive, is transported (in particular in the pump and/or the delivery line) out of the delivery unit components which are filled with liquid additive, during the draining process in step b). It is expedient for such an amount of liquid additive to be transported out that the residual amount of liquid additive that may remain in the delivery unit cannot lead to damage to the delivery unit if the liquid additive freezes.
  • the threshold temperature of the switch is set, for example, in the range from ⁇ 7° C. to ⁇ 10° C. in order to drain the delivery unit when there is a threat of freezing of the liquid additive.
  • the liquid additive is preferably delivered back into the tank from the delivery unit counter to the delivery direction.
  • the liquid additive is replaced by gas or by air.
  • the gas or the air is preferably sucked in by a supply device during the draining process. If the supply device is disposed at an exhaust-gas treatment device, under certain circumstances impurities from the exhaust gas are also sucked into the delivery unit.
  • a control unit is activated by using the switch in step a), and the control unit controls the draining in step b).
  • a control unit is activated by using the switch in step a) and the control unit controls the draining process.
  • the control unit controls the draining process.
  • a pump is activated for the draining.
  • valves may additionally be expedient for valves to be opened, through which the draining then takes place.
  • a control unit it is advantageous for a control unit to be used which performs the coordination.
  • the control unit can, for example, also be the engine control unit of a motor vehicle which is activated or woken up by step a).
  • control unit automatically deactivates after the execution of the method.
  • the current consumption of the method can be further reduced by using an automatic deactivation of the control unit after the execution of step b).
  • a deactivation switch is present which, like the currentless switch, is configured to interrupt the electrical connection.
  • the deactivation switch is not actuated in a currentless fashion as a function of the temperature but instead can be actuated by the control unit itself through a signal line.
  • the deactivation switch is actuated only if the delivery line is already drained (to the desired extent). If the deactivation switch has been activated, it is no longer possible to activate the control unit by using the currentless switch.
  • the deactivation switch can also be integrated in the control unit. In other words, the control unit can have an (internal) shut-down device which deactivates the control unit independently of the position of the currentless switch.
  • step a) between step a) and step b), a temperature measurement is performed by using a temperature sensor in order to check whether or not a threshold temperature has actually been undershot, and the liquid additive is removed from the delivery unit in step b) only if the threshold temperature has actually been undershot.
  • the control unit additionally performs a check of the temperature by using (at least) an (additional and/or electrical) temperature sensor, in order to ensure that the delivery unit is drained only if the threshold temperature has actually been undershot.
  • the (sensor-measured) threshold temperature may deviate from the threshold temperature for the activation of the currentless switch in step a), in order, if appropriate, to avoid an unnecessary draining of the delivery unit in step b).
  • a threshold temperature of the switch can be set in such a way that the control unit is already activated at a temperature of ⁇ 7° C.
  • the actual draining (step b) can then be carried out, with this then being triggered by a measurement result determined at the temperature sensor. Due to such additional checking of the temperature it is possible to detect particularly reliably situations in which draining of the delivery line is necessary. In particular it is also possible for the accuracy of the limiting temperature of the currentless switch to be lower than the accuracy of the temperature measurement with the additional temperature sensor.
  • the threshold temperature can have an uncertainty level of more than ⁇ 3° C., while the accuracy of the additional sensor is less than ⁇ 1° C. As a result of the additional checking, this inaccuracy of the currentless switch can be at least partially compensated.
  • step b) after step b), it is stored in a memory that the delivery unit has been drained, and before step a) and/or after step a), it is checked on the basis of the information in the memory whether or not the system has already been drained, and at least step b) is carried out only when the system has not been drained.
  • the present state of the delivery unit (drained or not drained) is stored in a memory, it is possible to avoid situations in which the described method is executed multiple times during a (single) stoppage of operation. It is possible, in particular, to avoid a situation in which the delivery unit is damaged by the attempt to re-drain the already drained delivery unit.
  • An (electronic) memory for checking whether step b) is to be carried out can alternatively or additionally be taken into account for the deactivation of the control unit with a deactivation switch.
  • the information as to whether draining was carried out or not, stored in the memory can, in particular also be used during re-activation of the delivery unit in order, where appropriate, to perform refilling of the delivery unit when the delivery unit has been drained.
  • the delivery unit is drained by back-suction of the liquid additive back into a tank.
  • Back-suction counter to a normal delivery direction is a particularly advantageous way of draining the delivery unit in step b).
  • the back-suction is made possible by using a (single) pump which can be operated counter to the normal delivery direction.
  • a return line which branches off from the delivery line, in such a way that draining is performed by using delivery in a circuit. It is also possible for a separate pump to be used for the back-suction.
  • Draining preferably takes place counter to a (normal) delivery direction of the delivery unit, wherein the (normal) delivery direction extends from the tank to the supply device along a delivery line.
  • the delivery direction of the pump is reversed for this purpose. Depending on the construction of the pump, this can take place by reversing the drive direction of the pump or by suitable switching of valves which are assigned to the pump.
  • the feed device is the same feed device used for feeding the liquid additive to a consumer (for example an exhaust-gas treatment device). It is also possible for an additional valve to be provided through which air can be sucked into the delivery unit during the draining.
  • a further possibility for the draining in step b) is for the delivery unit to be (partially) blown empty by using air.
  • a compressed-air line may be utilized which is connected to the delivery unit or to the line system.
  • the switch is at least a switch from the following group:
  • bimetal switch In the case of a bimetal switch, two different materials with different thermal coefficients of expansion are disposed adjacent one another and connected to one another.
  • the form/shape of the bimetal configuration varies as a result of temperature variations. For example, the configuration bends.
  • the variation of the form/shape may be utilized to mechanically close a contact. An electrical connection can be closed in this way.
  • shape memory alloy In the case of a shape memory alloy, the form of a component varies due to a phase change, whereby the electrical connection can be closed.
  • a nickel-titanium alloy is mentioned herein as an example of a shape memory alloy.
  • Polymer materials which exhibit shape memory characteristics may also be used for the switch.
  • a temperature switch with a liquid may, for example, have a sleeve filled with liquid. If the liquid freezes, its volume changes. The change in volume can be utilized to thereby close an electrical connection.
  • a (mechanically) prestressed switch which is used for the described method is preferably constructed in such a way that when the threshold temperature is reached the switch experiences a sudden change in shape which produces an electrical contact.
  • a switch can include, for example, a prestressed expansion material (for example a mechanically prestressed metal) which up to the threshold temperature is located in a first position and changes into a second position when the threshold temperature is reached.
  • a prestressed expansion material for example a mechanically prestressed metal
  • the expansion material in the first position the expansion material is preferably located in a prestressed (unstable) position and is prestressed (for example against a stop).
  • the expansion material can no longer be held in the first position and changes (suddenly) into a second position.
  • an actuator with which the prestressed switch can be actively moved back into the prestressed first position can also be present.
  • the method is executed during a standstill phase of an internal combustion engine.
  • the draining or the execution of step b) is (actively) prevented during the operation of an internal combustion engine.
  • the delivery unit is usually required to feed the liquid additive to the exhaust-gas treatment device of the internal combustion engine in order to ensure effective exhaust gas purification.
  • the draining should therefore preferably not take place. It is therefore advantageous if the non-electronic switch is bypassed and/or blocked during operation of an internal combustion engine.
  • a delivery unit comprising a currentless switch such as is used for step a) of the described method.
  • the advantages and structural features explained for the described method can be transferred analogously to the described delivery unit.
  • the delivery unit preferably has a housing in which the pump, the switch and at least one portion of the delivery line are situated.
  • a control unit or controller which is configured or programmed to execute the described method.
  • the delivery unit with the switch constitutes a component that can be installed in a motor vehicle (in particular a tank).
  • the motor vehicle is shut down at temperatures above the freezing point of urea, wherein the freezing point of urea is the freezing point of the liquid additive.
  • the control unit is in a rest state (ignition off). If the vehicle is shut down for a relatively long period of time, it must be ensured that repeated draining by suction (activation of pump and injector) does not take place. Draining by suction can be performed only once between two engine starting processes. The following measures may therefore be implemented:
  • FIG. 1 is a schematic and block diagram of a motor vehicle having a delivery unit which is configured to carry out the method described herein;
  • FIG. 2 is a diagrammatic, longitudinal-sectional view of a first embodiment variant of a currentless switch
  • FIG. 3 is a longitudinal-sectional view of a second embodiment variant of a currentless switch.
  • FIG. 4 is a longitudinal-sectional view of a third embodiment variant of a currentless switch.
  • a motor vehicle 11 having at least one internal combustion engine 8 and having an exhaust-gas treatment device 12 for the purification of exhaust gases of the internal combustion engine 8 .
  • the exhaust gases from the internal combustion engine 8 can be purified with an SCR catalytic converter 14 provided in the exhaust-gas treatment device 12 .
  • the method of selective catalytic reduction can be carried out at the SCR catalytic converter 14 using liquid additive (such as an aqueous urea solution), which can be fed to the exhaust-gas treatment device 12 with a feed device 13 on a delivery unit 1 .
  • the feed device 13 has a pump 10 and a delivery line 9 .
  • the delivery line 9 runs from an extraction point 17 on a tank 7 through the pump 10 to the feed device 13 .
  • the direction from the tank 7 to the feed device 13 is designated as a feed direction 18 .
  • the motor vehicle 11 has a control unit or controller 4 . Active draining of the delivery line 9 of the delivery unit 1 can be carried out with the control unit 4 .
  • the control unit 4 is supplied with electrical energy and/or with electrical signals through an electrical connection 2 by a supply device or supplier 15 .
  • This electrical connection 2 has a switch 3 which is actuated as a function of temperature. When the temperature drops resulting in a (predefined, lower) threshold temperature being reached, the switch 3 closes the electrical connection 2 in order to activate the control unit 4 .
  • a deactivation switch 19 can also be provided on the electrical connection 2 .
  • the control unit 4 can control the deactivation switch 19 again later through a deactivation line 20 in order to deactivate the control unit 4 independently of the position of the switch 3 .
  • the control unit 4 can also have a memory 6 (which acquires and/or archives electrical data) in which information as to whether or not the delivery unit 1 has been drained is stored.
  • the control unit 4 is connected to the pump 10 through a control line 16 in order to control the pump 10 . It is furthermore advantageous if the switch 3 can be bypassed and/or blocked by a bypass 21 during operation of an internal combustion engine 8 .
  • the motor vehicle 11 preferably also has a temperature sensor 5 which is connected to the control unit 4 and with which the control unit 4 can independently monitor the temperature which is present, in order to check whether or not the draining of the delivery unit 1 is actually to be carried out.
  • FIG. 2 shows a switch 3 which is suitable for the described method and which is embodied as a bimetal switch 23 .
  • This bimetal switch 23 is composed of a first metal 24 and a second metal 25 which are permanently connected to one another.
  • the first metal 24 and the second metal 25 have different coefficients of thermal expansion.
  • the bimetal switch therefore deforms when the temperature changes.
  • the bimetal switch 23 is configured in such a way that electrical contacts 22 make contact with one another when a threshold temperature is reached in order to produce an electrical connection 2 .
  • FIG. 3 shows a switch 3 which is suitable for the described method and which functions by using a fluid (an expansion fluid 27 ).
  • the switch 3 has a reservoir 28 which is filled with the expansion fluid 27 .
  • the switch 3 also has a temperature pickup body 26 for picking up the ambient temperature and for passing the ambient temperature on to the expansion fluid 27 .
  • the expansion fluid 27 is connected to a piston 29 . If the temperature of the expansion fluid 27 decreases or increases, the piston 29 moves. When a threshold temperature is reached, the piston 29 is moved in such a way that the electrical contacts 22 make contact with one another and an electrical connection is produced.
  • FIG. 4 shows a switch 3 which is suitable for the described method and is prestressed (mechanically).
  • This switch 3 has an expansion material 35 which is, for example, a metal and which is lengthened or shortened as a function of the ambient temperature.
  • the expansion material 35 is mounted in a frame 31 and is located in a first position 32 in which it is prestressed against a stop 30 .
  • the expansion material 35 which is illustrated in FIG. 4 preferably expands when the ambient temperature drops. When a threshold temperature is reached, the expansion material 35 has expanded to such an extent that it tips over or flips over from the first position 32 into a second position 33 .
  • An electrical connection is then produced between the two electrical contacts 22 .
  • An actuator 34 with which the expansion material 35 can be reset actively back into the first position 32 , is also preferably provided.

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  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Combustion & Propulsion (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Health & Medical Sciences (AREA)
  • Toxicology (AREA)
  • Exhaust Gas After Treatment (AREA)
  • Loading And Unloading Of Fuel Tanks Or Ships (AREA)
US14/518,096 2012-04-19 2014-10-20 Method for draining a delivery unit for liquid additive, delivery unit and motor vehicle having a delivery unit Abandoned US20150033712A1 (en)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
DE102012103453.2 2012-04-19
DE201210103453 DE102012103453A1 (de) 2012-04-19 2012-04-19 Verfahren und Vorrichtung zur Entleerung einer Fördereinheit für ein flüssiges Additiv
PCT/EP2013/057896 WO2013156475A1 (de) 2012-04-19 2013-04-16 Verfahren und vorrichtung zur entleerung einer fördereinheit für ein flüssiges additiv

Related Parent Applications (1)

Application Number Title Priority Date Filing Date
PCT/EP2013/057896 Continuation WO2013156475A1 (de) 2012-04-19 2013-04-16 Verfahren und vorrichtung zur entleerung einer fördereinheit für ein flüssiges additiv

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US20150033712A1 true US20150033712A1 (en) 2015-02-05

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US14/518,096 Abandoned US20150033712A1 (en) 2012-04-19 2014-10-20 Method for draining a delivery unit for liquid additive, delivery unit and motor vehicle having a delivery unit

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JP2015517053A (ja) 2015-06-18
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CN104271908A (zh) 2015-01-07
EP2844852B1 (de) 2016-11-23
EP2844852A1 (de) 2015-03-11
WO2013156475A1 (de) 2013-10-24
RU2014146227A (ru) 2016-06-10
KR20140132413A (ko) 2014-11-17
IN2014DN07502A (de) 2015-04-24

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