Classifications

• • 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
  • F04B53/00—Component parts, details or accessories not provided for in, or of interest apart from, groups F04B1/00 - F04B23/00 or F04B39/00 - F04B47/00
  • F04B53/04—Draining
• • 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
  • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
  • F04B—POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS
  • F04B43/00—Machines, pumps, or pumping installations having flexible working members
  • F04B43/0009—Special features
  • F04B43/0081—Special features systems, control, safety measures
• • 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
  • F04B43/00—Machines, pumps, or pumping installations having flexible working members
  • F04B43/12—Machines, pumps, or pumping installations having flexible working members having peristaltic action
• • 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
  • F04B49/00—Control, e.g. of pump delivery, or pump pressure of, or safety measures for, machines, pumps, or pumping installations, not otherwise provided for, or of interest apart from, groups F04B1/00 - F04B47/00
  • F04B49/10—Other safety measures
  • F04B49/106—Responsive to pumped volume
• • 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
  • F01N2610/02—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
  • F01N2610/1486—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
  • 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

Definitions

• the invention relates to a method for operating a device for the provision of liquid additive.
• Devices for providing liquid additive are used, for example, in motor vehicles to supply exhaust aftertreatment devices with a liquid additive such as fuel and / or urea water solution.
• Exhaust gas treatment devices to which a liquid additive is supplied, are used in particular in motor vehicles with diesel engines.
• exhaust gas treatment systems or exhaust gas treatment processes are typically used to purify the exhaust gases, in which nitrogen oxide compounds in the exhaust gas are reduced by the aid of a liquid additive.
• Particularly often urea-water solution is used as a liquid additive, the z. B. for the purpose of the method of selective catalytic reduction with a urea content of 32.5% under the trade name AdBlue® is available.
• liquid water-based additives can freeze at low temperatures.
• the described urea-water solution AdBlue® freezes at -11 ° C.
• Such low temperatures can occur in motor vehicles, especially during long downtimes.
• By freezing the liquid additive occurs an increase in volume of the liquid additive.
• This increase in volume can lead to a significant pressure increase in the system and therefore there is a risk that certain components of the device may be damaged or even destroyed.
• the invention relates to a method for operating a device for providing a liquid additive with a conveying path along which the liquid additive is conveyed, wherein the conveying path has at least one first section, in which a peristaltic pump is arranged, which consists of the liquid additive precipitated deposits can be damaged, and the conveyor further comprises at least a second portion in which a freezing-sensitive component is arranged.
• the method has at least the following steps:
• the liquid additive is preferably urea-water solution.
• a conveying path from an intake point in a tank to an addition point for the liquid additive to an exhaust gas treatment device is meant by the conveying path.
• the conveying path is at least predominantly formed by a line and / or a channel through which the liquid additive is conveyed.
• the liquid additive is stored in the tank.
• the suction point is preferably formed in the vicinity of the tank bottom so that the liquid additive stored in the tank can be conveyed as completely as possible out of the tank.
• the addition point to the exhaust gas treatment device preferably has at least one injector and / or nozzle and / or a (passive) valve.
• the liquid additive of the exhaust gas treatment device may preferably be fed with fine atomization (possibly by means of compressed air).
• One Injector allows dosage of the liquid additive.
• a dosage is made goal-oriented, for example, by setting the opening time of the injector.
• On or in the conveying path a conveying means is preferably arranged, with which the promotion of the liquid additive takes place.
• the conveying means is preferably at least one pump.
• a conveying means for example, a piston pump, a diaphragm pump or a positive displacement pump can be used.
• the conveying means is adapted to convey the liquid additive from the suction point along the conveying path with a corresponding conveying direction to the point of addition.
• the first section and the second section are regions of the conveying path, which are arranged in the conveying direction of the liquid additive through the conveying path from the tank to the addition point (possibly directly) one behind the other.
• the conveying path can have a plurality of first sections and / or a plurality of second sections.
• a first section is preferably arranged.
• the freeze-sensitive component is a (in particular electronic and / or mobile) component, which in particular has the property that it can be damaged by a volume expansion during freezing of the - located in the vicinity - liquid additive.
• a component is, for example, a sensitive sensor element, such as a pressure sensor.
• a pressure sensor typically measures a pressure change via deformation of a movable pressure receiving member. Due to the large volume expansion during freezing, such a pressure sensor can therefore be damaged very easily, because a permissible maximum expansion is exceeded.
• the freeze-sensitive component can also be a valve that is not designed for the loads that occur during freezing.
• a peristaltic pump is also referred to below as an operating component.
• a peristaltic pump or an operating component is a component of the device which is in contact with the liquid additive or through which the additive flows.
• the peristaltic pump actively realizes a promotion and / or an active compensation of movements of the additive in the device.
• a peristaltic pump or an operating component detects components that move themselves within or adjacent to the lines for the additive. These components may, for example, have sealing surfaces that are exposed to liquid additive. The imminent damage due to precipitated deposits can be done here, for example, by abrasive machining of sealing surfaces, blockage of closing arrangements, agglomeration of deposits, etc.
• the peristaltic pump is designed, in particular, so that it can realize a reversible conveying direction, that is to say it can convey additives in a predetermined manner in two opposite directions.
• a peristaltic pump is a positive displacement pump in which the additive to be delivered z. B. by external mechanical deformation of a flexible conduit (such as a hose) is pushed therethrough.
• the conveying of liquid additive along the conveying path in step a) corresponds to a normal operation of a device for providing the liquid additive.
• the liquid additive is supplied, for example, to an exhaust gas treatment device.
• a motor vehicle in which the described device is installed is operated regularly. This means that the internal combustion engine of the motor vehicle is running and exhaust gases of the combustion engine are cleaned in the gas treatment device from Ab.
• Stopping the production in step b) corresponds to a normal stop of production.
• Such a typical stop of operation typically takes place in parallel with an operation stop of the motor vehicle, in which the combustion engine and the exhaust treatment device of the motor vehicle are deactivated or stopped.
• step c) the conveying path is partially emptied, with second sections being emptied and liquid additive remaining in first sections.
• Freeze-sensitive components of the device are preferably arranged only on second sections, which are emptied in step c).
• other operating components can exist which can be damaged by deposits precipitated from the liquid additive, which are arranged in first sections and which are not emptied in step c).
• further pumps and / or multiple peristaltic pumps may be arranged in first sections of the delivery path of the device.
• the described method is based on the finding that, especially in the case of devices which are emptied during an operating stop, damage due to abrasive discharges from the liquid additive is particularly frequent. It has been found that such deposits are formed in particular when the device for providing liquid additive is emptied and residual droplets of the liquid additive then evaporate. When the liquid additive is urea-water solution and evaporates, crystalline urea particles (such as biuret) remain which form the precipitates described. The risk of formation of deposits is substantially lower in areas of the conveying path which are completely filled with liquid additive. In such areas, on the one hand less evaporation occurs.
• the liquid additive also remains after step c).
• the emptying takes place in step c), preferably only partially and in such a targeted manner that liquid additive remains in the first sections while second sections are emptied.
• the device is preferably constructed so that at least one of the following effects ensures that the liquid additive present in the at least one first section can not shift: capillary forces, surface tension effects of the additive, and hydrostatic forces.
• capillary forces surface tension effects of the additive
• hydrostatic forces hydrostatic forces.
• the method is particularly advantageous when the liquid additive is conveyed along the conveying path in step a) with a conveying direction, and the emptying in step c) takes place at least predominantly counter to the conveying direction. It is preferred that for discharging the conveying path according to step c), a conveying direction of a pump (in particular the peristaltic pump) for conveying the liquid additive is reversed.
• a pump in particular the peristaltic pump
• a conveying means in particular a pump or peristaltic pump - also collectively referred to below as "pump"
• Liquid additive is then typically forced back into the tank through the suction point on the tank.
• gas or air is sucked.
• the conveying path is then filled with air or gas, which replaces the liquid additive.
• each portion of the recirculated additive is conveyed exclusively towards the suction, but it can also be provided that on the conveying path z.
• B. at least one (branching) storage volume is provided, in which a (small) portion of the recirculated additive during step c) flows. In the latter case, however, the "predominant portion" of the returned additive is withdrawn from the conveying direction counter to the conveying direction.
• Such a reversal of the conveying direction of a pump is a technically particularly simple variant in order to realize a reversible conveying direction in a device.
• a section of the conveying path is deformed in the manner of a peristaltic movement in order to move the liquid additive in the conveying direction, such a pump preferably having a rotary drive and the peristaltic movement via a movable pump element
• the movable pump element can, for example, be an eccentric, and such a pump is preferably designed such that a reversal of the conveying direction is possible by reversing the drive direction of the drive.
• a device for providing liquid additive has two (possibly different) conveying means, wherein a first conveying means is adapted to promote liquid additive in the regular operation (step a)) and a further conveying means is set to empty the conveyor against the direction of conveyance.
• the two subsidies may be arranged along the conveying path in series or parallel to one another in parallel regions of the conveying path.
• the device for providing the liquid additive has a return line, which branches off from the conveying path and leads back into a tank.
• the emptying of the conveying path can also be done by the return line.
• pumps for conveying liquid additives can easily be damaged by precipitated deposits from the liquid additive. This is because a pump has moving parts and therefore the precipitates as abrasive particles can cause abrasion on the pump which damages the pump.
• the effects of precipitated deposits on peristaltic pumps are particularly strong.
• surfaces of the conveying path are typically pressed against one another or rubbed against one another. The deposits are therefore in peristaltic pumps in particularly intensive abrasive contact with the moving parts of the pump.
• peristaltic pumps make it particularly easy to empty the delivery path by reversing the drive direction of the pump.
• the method is advantageous if, for the partial emptying of the delivery path in step c), a pump is operated for a predetermined time interval is, wherein the time interval is selected so that in the at least a first portion of liquid additive remains.
• the emptying of the conveying path requires a period of time that is dependent on the structure of the device, but that is easy to determine. This period of time is particularly dependent on the length of the conveying path and the (rear) conveying speed of the liquid additive in the conveying path.
• the variant embodiment of the method is particularly advantageous if the at least one first section lies in the conveying direction from the suction point to the point of addition in front of the at least one second section. Furthermore, the method is advantageous if the partial emptying of the conveying path is monitored in step c) with at least one sensor element, wherein the sensor element is arranged at a point of the conveying path and adapted to detect whether liquid additive is present at the point, and on the emptying is stopped as soon as there is no liquid additive at the point.
• the sensor element may, for example, consist of two electric pins, between which there is an electrically conductive connection, as long as liquid additive is applied to the pins. If the liquid additive is no longer applied to the pins, the electrical connection is disconnected and it can be seen that there is no longer any liquid additive at the point.
• Such a sensor Element for detecting whether liquid additive is present or not is particularly advantageous if, due to uncertainties regarding the conveying speed for the liquid additive when emptying a pure time control for monitoring step c) is not sufficient.
• the sensor element may in principle be provided to also assume other monitoring functions, a separate (technically simply constructed) separate sensor element may be used which is provided only for the aforementioned purpose. It is also advantageous if the sensor element is a pressure sensor and the pressure measured by the pressure sensor changes depending on the degree of filling of the conveying path.
• step c it is possible to detect via the pressure to what extent the delivery path is already emptied during step c) in order to stop the emptying as soon as the at least one second section is emptied and if there is still liquid additive in the at least one first section ,
• a dependence between the pressure at a pressure sensor and the degree of filling of the conveying path may be due, for example, to the hydrostatic pressure of the liquid additive in the conveying path. So the hydrostatic pressure is greater, the more liquid additive is present in the conveying path.
• a pressure sensor is normally provided in a device for providing liquid additive to monitor and / or regulate the regular operation of the device during the provision of the liquid additive (step a)). It is particularly advantageous if this pressure sensor is additionally used in step c) in order to monitor to what extent the conveying path has already been emptied. Then no additional components are necessary for the monitoring of step c).
• an operating parameter the pump changes depending on a degree of filling of the conveying path with liquid additive and an operation of the pump is stopped for emptying upon reaching a predetermined value of the operating parameter.
• an operating parameter may be, for example, a response of the pump to an applied operating current.
• a movable pump element reacts faster with a movement to an applied operating current when the amount of liquid additive in the conveying path is lower. This may be the case because the amount of liquid additive to be moved by the pump is already reduced in this case.
• the monitoring of the degree of filling of the conveying path on the basis of an operating parameter of a pump makes it possible to dispense with additional components for monitoring the emptying in step c). Furthermore, the method is advantageous when the pump is placed during emptying at least a predetermined time in a diagnostic mode, wherein the dependent on the degree of filling of the delivery path operating parameters of the pump is determined during the diagnostic mode.
• a diagnostic mode is meant a specific mode of operation of the device which is only activated to monitor the degree of filling of the delivery path.
• the diagnostic mode can be, for example, in a special pump pulse, which is generated with a predetermined or defined diagnostic drive current of the pump.
• a degree of filling of the conveying path is determined on the basis of a pressure and / or a pressure change, which is measured with a pressure sensor and which occurs when the pump exerts a pump pulse.
• This pump pulse can be a normal pulse (as during normal operation of the pump during emptying) and / or a special pump pulse (corresponding to a special diagnostic mode for monitoring the degree of filling).
• the method is advantageous if, for partial emptying of the conveying path in step c), the conveying path is first completely emptied and the conveying path is then partially filled with liquid additive, so that liquid additive is present in the at least one first section.
• this mode of operation it is preferably not initially monitored whether the delivery path is only partially emptied or not. It is therefore always ensured that a complete emptying of the conveyor was done. This can be done, for example, by operating a pump for draining the delivery path for a time interval that is sufficiently long to ensure complete draining of the delivery path in each case. Subsequently (ie in particular immediately after and / or without termination of the "operating stop"), a (only) partial refilling of the conveying path is carried out, whereby the conveying path is not completely refilled. which are also suitable for monitoring the emptying.
• Such a two-stage process procedure in which first a complete emptying and then only a partial filling takes place, may be advantageous because the amount that is conveyed out of the conveyor during emptying is typically substantially greater than the amount that is refilling is transported back into the conveyor. Therefore, it is much easier to refill precisely so that liquid additive remains in the first section while the second section is completely deflated.
• step c) it is preferred that in step c) the partial refilling takes place after a complete emptying of the conveying path via the return line.
• the first sections of the conveying path with liquid additive, which lie downstream in the conveying direction behind second sections which are to remain empty. If the conveying path in step c) is first completely emptied, this can then be alternately and purposefully filled by the addition point with gas or air and the return line with liquid additive.
• This alternating filling can be carried out in such a way that after step c) there is liquid additive in first sections which has passed through the return line into the conveying path, while in second sections there is gas or air which has entered the conveying path through the point of addition.
• a feed pump can also reverse its conveying direction.
• intended amounts of the liquid additive can be promoted targeted in the sections of the conveying path between the return line and the point of addition.
• the method is also advantageous if the conveying path has at least one siphon, wherein the at least one first section is arranged in the siphon.
• Such a siphon is characterized in particular by a U-shaped design of the conveying path.
• there is a lower region of the conveying path which is adjacent to two elevated regions of the conveying path.
• the raised areas are higher in relation to their geodesic position than the lower area.
• a residual amount of the liquid additive typically accumulates due to gravity when the delivery path is partially deflated.
• the first section is arranged in such a siphon. The structural measure of a siphon can ensure that the amount of liquid additive present in the conveying path remains in the first section even in the case of external influences.
• a siphon is therefore a particularly reliable way to maintain the partial emptying of the conveying path in the desired shape with empty second sections and a filled first section, even during long downtimes of a motor vehicle.
• the integration of at least one siphon in the conveying path can be expressly combined with all described measures for producing a distribution of the liquid additive in the conveying path with filled first sections and empty second sections. It is also possible that, to maintain said distribution, only the described siphon is provided and in step c) no conscious (additional or active) method steps are carried out for generating the distribution.
• the invention finds particular application in a device for providing a liquid additive having a conveying path along which liquid additive is conveyed, wherein the conveying path has at least a first section in which a peristaltic pump is arranged which is damaged by deposits precipitated from the liquid additive can, and a second section, in which at least one freeze-sensitive component is arranged, wherein the device for implementing at least one variant of the method described above is set up.
• This device may have all of the device features illustrated above in connection with the described method.
• a motor vehicle comprising an internal combustion engine and an exhaust gas treatment device for cleaning the exhaust gases of the internal combustion engine.
• an addition point is preferably arranged, via which the exhaust gas treatment device s a liquid additive can be supplied with the described device.
• the point of addition may have the special features described above.
• an SCR catalyst is preferably provided, with which the method for selective catalytic converter lytic reduction can be carried out for exhaust gas purification.
• the exhaust gas treatment device can be fed via a feed point a liquid additive for performing the SCR process. So z. B. an injector supplied at the point of addition of the device described with liquid additive from a tank.
• the described device can preferably be operated according to a described method, wherein the implementation of the method with the device takes place with the aid of a control device in which the process steps required for carrying out the method or process sequences are stored.
• the control unit may for example be part of the engine control of the motor vehicle.
• FIGS. show particularly preferred embodiments, to which the invention is not limited.
• the figures and in particular the magnitudes shown are only schematically. Show it:
• FIG. 1 shows a device for carrying out the described method
• FIG. 2 shows a further variant of a device for carrying out the described method
• FIG. 3 shows a flow chart of the described method
• FIG. 4 shows yet another variant of a device for carrying out the described method
• FIG. 3 shows a flow chart of the described method
• FIGS. 1 and 2 each show a device 1 for providing a liquid additive (here in particular urea-water solution).
• This device 1 in each case has a tank 19 in which the liquid additive can be stored. Attached to the tank 19 is in each case a housing 21, in which the peristaltic pump 24 and, if appropriate, further operating components of the device 1 are arranged, with which the delivery of liquid additive takes place and which can be damaged by deposits precipitated from the liquid additive.
• the delivery of the liquid additive takes place at a suction point 20 out of the tank 19 with the conveying direction 5 along a conveying path 2 to an addition point 23. At the addition point 23, the liquid additive can be supplied to an exhaust gas treatment device 11.
• deposits 4 form, which are crystalline precipitates of the liquid additive here.
• the conveying path 2 is typically formed partly by a conveying channel 15 and partly by a supply line 14.
• a region of the conveying path 2 within the housing 21 is referred to here.
• the peristaltic pump 24 and optionally further operating components are arranged on the conveying path 2, which can be damaged by deposits precipitated from the liquid additive.
• a supply line 14 is here a region of the conveying path 2 outside of the housing 21 referred to, which is typically formed by a flexible conduit.
• the supply line 14 typically connects to the delivery channel 15 and provides a connection line between the addition point 23 and the housing 21 of the device 1.
• the exhaust treatment device 11 is typically spaced from the tank 19 and the housing 21 and this distance may be with the supply line 14 are bridged.
• the supply line 14 can be connected to the supply channel 15 at a connection 16.
• the conveying path 2 has first sections 3, in which at least one peristaltic pump 24 and optionally further operating components are arranged, which can be damaged by deposits 4 precipitated from the liquid additive.
• the conveying path 2 also has second sections 26, in which freeze-sensitive components 25 are arranged, which can be damaged by frozen liquid additive and the volume expansion of the freezing liquid additive.
• freeze-sensitive components 25 are, for example, sensors and / or an injector, which is arranged at the point of addition 23.
• a sensor element 7 is arranged in FIG. 1 by way of example at a point 8 of the conveying path 2, which has two electrically conductive tiller with which a conductivity of the liquid additive in the conveying path 2 can be monitored. If there is liquid additive at point 8, the electrical connection between the tines of the sensor element 7 is closed, while the electrical connection is disconnected, if there is no liquid additive at the point 8. Also shown in FIG. 1 is a pressure sensor 9 with which the degree of filling of the conveying path 2 can be monitored.
• the at least one first section 3 is preferably arranged in the region of the siphon 10.
• the at least one second section 26 is preferably arranged outside or above the siphon.
• FIG. 3 shows a flowchart of the described method for operating a device for providing liquid additive.
• process steps a), b) and c) wherein a) relates to a regular operation of the device.
• step b) the device is stopped and in step c), a partial emptying of the conveying path of the device takes place.
• step c) the evaporation phase 22, which is due to the partial emptying of the conveyor in step c).
• droplets of the liquid additive evaporate in the deflated areas of the conveying path. As a result, precipitates and thus deposits can form in the conveyor.
• FIG. 4 shows yet another embodiment of a device 1 for carrying out the method described.
• This device 1 also has a delivery path 2 which extends from a suction point 20 on a tank 19 with a conveying direction 5 to an addition point 23 on an exhaust gas treatment device 11. From the conveying path 2 branches off a return line 27, which is also connected to the tank 19.
• the conveying path 2 of this device 1 is first completely emptied in step c)
• the conveying path 2 in step c) can subsequently be filled alternately via the return line 27 with liquid additive and via the adding point 23 with gas or air again.
• it can be achieved in a targeted manner that liquid additive is present in first sections 3, whereas in second sections 26 there is no liquid additive.
• FIG. 5 shows a motor vehicle 12 with an internal combustion engine 13 and an exhaust gas treatment device 11 for cleaning the exhaust gases of the internal combustion engine 13.
• the exhaust gas treatment device 11 preferably has an SCR catalytic converter 18 with which the method of selective catalytic reduction for exhaust gas purification is carried out can be.
• the exhaust gas treatment s device 11 can be supplied with a device 1 at an addition point 23 liquid additive from a tank 19. At the point of addition 23, an injector and / or a nozzle are preferably arranged.
• the tank 19 and the addition point 23 are connected to a supply line 14, which partially forms a conveying path 2 for the liquid additive.
• the device 1 is connected to a control unit 17, which coordinates the implementation of the described method.
• the control device 17 may be part of an engine control of the motor vehicle 12. LIST OF REFERENCE NUMBERS

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)
• Reciprocating Pumps (AREA)

Applications Claiming Priority (2)

Publications (1)

Family

ID=49619918

Family Applications (1)

Country Status (7)

Families Citing this family (2)

Family Cites Families (16)

• 2012
  • 2012-12-07 DE DE102012111917.1A patent/DE102012111917A1/de active Pending
• 2013
  • 2013-11-15 WO PCT/EP2013/073974 patent/WO2014086572A1/de active Application Filing
  • 2013-11-15 KR KR1020157017636A patent/KR20150103023A/ko not_active Application Discontinuation
  • 2013-11-15 JP JP2015545727A patent/JP2016500412A/ja active Pending
  • 2013-11-15 EP EP13792665.5A patent/EP2929154A1/de not_active Withdrawn
  • 2013-11-15 US US14/650,400 patent/US10240595B2/en active Active
  • 2013-11-15 CN CN201380072422.3A patent/CN104968907B/zh active Active

Also Published As

Similar Documents

Legal Events