Classifications

• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
  • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
  • F01N3/00—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust
  • F01N3/08—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous
  • F01N3/10—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust
  • F01N3/18—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust characterised by methods of operation; Control
  • F01N3/20—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust characterised by methods of operation; Control specially adapted for catalytic conversion ; Methods of operation or control of catalytic converters
  • F01N3/2066—Selective catalytic reduction [SCR]
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01F—MEASURING VOLUME, VOLUME FLOW, MASS FLOW OR LIQUID LEVEL; METERING BY VOLUME
  • G01F23/00—Indicating or measuring liquid level or level of fluent solid material, e.g. indicating in terms of volume or indicating by means of an alarm
  • G01F23/22—Indicating or measuring liquid level or level of fluent solid material, e.g. indicating in terms of volume or indicating by means of an alarm by measuring physical variables, other than linear dimensions, pressure or weight, dependent on the level to be measured, e.g. by difference of heat transfer of steam or water
  • G01F23/24—Indicating or measuring liquid level or level of fluent solid material, e.g. indicating in terms of volume or indicating by means of an alarm by measuring physical variables, other than linear dimensions, pressure or weight, dependent on the level to be measured, e.g. by difference of heat transfer of steam or water by measuring variations of resistance of resistors due to contact with conductor fluid
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01F—MEASURING VOLUME, VOLUME FLOW, MASS FLOW OR LIQUID LEVEL; METERING BY VOLUME
  • G01F23/00—Indicating or measuring liquid level or level of fluent solid material, e.g. indicating in terms of volume or indicating by means of an alarm
  • G01F23/22—Indicating or measuring liquid level or level of fluent solid material, e.g. indicating in terms of volume or indicating by means of an alarm by measuring physical variables, other than linear dimensions, pressure or weight, dependent on the level to be measured, e.g. by difference of heat transfer of steam or water
  • G01F23/26—Indicating or measuring liquid level or level of fluent solid material, e.g. indicating in terms of volume or indicating by means of an alarm by measuring physical variables, other than linear dimensions, pressure or weight, dependent on the level to be measured, e.g. by difference of heat transfer of steam or water by measuring variations of capacity or inductance of capacitors or inductors arising from the presence of liquid or fluent solid material in the electric or electromagnetic fields
  • G01F23/263—Indicating or measuring liquid level or level of fluent solid material, e.g. indicating in terms of volume or indicating by means of an alarm by measuring physical variables, other than linear dimensions, pressure or weight, dependent on the level to be measured, e.g. by difference of heat transfer of steam or water by measuring variations of capacity or inductance of capacitors or inductors arising from the presence of liquid or fluent solid material in the electric or electromagnetic fields by measuring variations in capacitance of capacitors
  • G01F23/268—Indicating or measuring liquid level or level of fluent solid material, e.g. indicating in terms of volume or indicating by means of an alarm by measuring physical variables, other than linear dimensions, pressure or weight, dependent on the level to be measured, e.g. by difference of heat transfer of steam or water by measuring variations of capacity or inductance of capacitors or inductors arising from the presence of liquid or fluent solid material in the electric or electromagnetic fields by measuring variations in capacitance of capacitors mounting arrangements of probes
• • 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
  • F01N2610/1406—Storage means for substances, e.g. tanks or reservoirs
• • 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
  • F01N2900/00—Details of electrical control or of the monitoring of the exhaust gas treating apparatus
  • F01N2900/06—Parameters used for exhaust control or diagnosing
  • F01N2900/18—Parameters used for exhaust control or diagnosing said parameters being related to the system for adding a substance into the exhaust
  • F01N2900/1806—Properties of reducing agent or dosing system
  • F01N2900/1814—Tank level
• • 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

Definitions

• the present invention relates to an apparatus for determining a tank level and / or a quality of the tank contents, in particular for a tank with a urea-water solution. Since an application of urea-water solution for cleaning exhaust gases of mobile internal combustion engines is often used, the invention relates in particular to an apparatus for use in the automotive sector.
• Urea-water solution is used in particular in the context of the so-called SCR process in the treatment of exhaust gases.
• the aim of this method is to reduce the nitrogen oxides in the exhaust.
• ammonia or the ammonia precursor urea is often proposed as a reducing agent.
• the addition of the ammonia or the urea-water solution is carried out regularly depending on the nitrogen oxides to be decomposed in the exhaust gas.
• this reducing agent is therefore a resource whose storage is to be monitored.
• the quality of the urea-water solution is also of interest here, since only in this way can it be ensured that the required amount of ammonia is generated during operation of the internal combustion engines, in particular a diesel engine , is needed.
• the apparatus according to the invention for determining a tank level comprises at least: a cap, a removal tube which extends through the cap and at least partially comprises an electrically conductive material, a jacket tube which is arranged around the withdrawal tube and at least partially an electrically conductive material comprising a measuring unit which forms a first electrode with the extraction tube and with the jacket tube a second electrode.
• the apparatus described here is preferably an independent component which can in particular replace conventional tank closure elements or tank lids.
• the cap z. B. a corresponding screw connection and / or seal, with which it can be attached to the tank.
• the cap also allows the fixation or alignment of the sampling tube and the jacket tube in the tank inside, where appropriate, the measuring unit is located on the opposite, outer side.
• the cap can of course be more Components such as cables, resistance heaters, sensors, connectors, adapters, etc.
• the sampling tube is used to remove the tank contents, such as a urea-water solution.
• the sampling tube outside the tank z. B. connected to a pump with which the tank contents conveyed out through the sampling tube and finally the exhaust gas is added.
• the removal tube is preferably made entirely of an electrically conductive material, which should in particular also be resistant to the urea-water solution.
• Metals which are corrosion-resistant to solutions of reducing agent precursor (for example urea) are particularly suitable as material for the removal tube.
• Particularly advantageous here is the use of a stainless steel, an austenitic steel, a chromium-nickel steel and / or a nickel-based material. Preference is given here one of the following materials: No. 1.4301, No.
• a steel with material number 1.4828 is understood to mean a steel which has a max. 0.2% by weight (weight%) of carbon, 1.5 to 2.5% by weight of silicon, maximum of 2% by weight of manganese, maximum of 0.045% by weight of phosphorus, maximum of 0.03% by weight % Sulfur, 19 to 21% by weight chromium and 11 to 13% by weight nickel.
• a steel with material number 1.4301 is understood as meaning a steel which has a maximum of 0.07% by weight of carbon, a maximum of 1% by weight of silicon, a maximum of 2% by weight of manganese, a maximum of 0.045% by weight of phosphorus, 17 to 19, 5 wt .-% chromium, 8 to 10.5 wt .-% nickel and at most 0.11 wt .-% nitrogen.
• the material numbers are given in particular according to DIN EN 10027-2.
• the jacket tube preferably extends over the largest part of the removal tube, in particular it covers (almost) the entire length of the withdrawal tube.
• the sampling tube and the jacket tube are arranged in particular concentric to each other.
• additional components may be provided, such as heating elements.
• the jacket pipe too, must withstand the ambient conditions, such as the extraction pipe. In that regard, it offers Here, too, to use one of the aforementioned materials for the construction of the jacket tube. Optionally, it may also be useful to use different materials here.
• the measuring unit can in particular also be designed in the manner of a data processing device.
• the processing of the electrical signals can thus be carried out directly in the measuring unit.
• data models can be stored in the measuring unit, which allows an analysis or evaluation of the electrical signals.
• the measuring unit form corresponding electrical circuits and connections to other components of the apparatus and / or the motor vehicle.
• the sampling tube and the jacket tube respectively are used as electrodes for a capacitive level measurement.
• the first electrode and the second electrode form an electrical capacitor.
• a low initial capacity can be measured. If the tank level is increased, the capacity increases as the coverage of the electrodes increases.
• the measurement unit may also include amplifiers and similar elements to enhance signal evaluation. As an electrical variable, for example, the electrical resistance, the capacitance or comparable sizes between the electrodes can be determined.
• the non-conductive region between the two electrodes has a certain length or height. This means in other words z. B., that one, if the lower part of the jacket tube to a height of about 2 cm insulated or coated, a reserve indicator
• the sampling tube and the jacket tube are connected to each other by means of an insulating adhesive or a Keramiklötung.
• the insulating adhesive fulfills the function of electrically insulating the jacket tube and the extraction tube against each other.
• this electrode may also be used as a "reference electrode.”
• a material that is resistant to urea is preferably used, which does not change its properties under the influence of urea or a urea solution Urea solution in particular not soluble.
• ceramic brazing For brazing metal with ceramic and / or ceramic with ceramic (both referred to collectively herein as "ceramic brazing"), one of the following two principles of operation is proposed in particular: a) brazing metallized ceramic and b) active brazing Coating surface of the ceramic component is coated with a metal, so that then in the soldering process, the wetting of the ceramic joining partner is made possible by conventional solders.Alternative soldering is usually a direct soldering process, in which the active element is added directly to the solder The active solder used for ceramic soldering is suitable for making solder joints between two ceramics or between ceramics and metal the verb induction is brought about. Due to the alloy composition, the active solder wet non-metallic, inorganic materials.
• the active solder can at least partially comprise silver, titanium, copper and / or indium and is optionally embodied as a eutectic alloy. Preference is given here to a solder which consists of approximately 72% by weight of silver and 28% by weight of copper and has a melting point of about 780 ° C. Such a lot is z. B. under the trade name Lot Degussa 7200 or CuSiI available.
• a ceramic material can be used to isolate the sampling tube and the jacket tube. At the same time, a permanent bond that is not penetrable for urea solutions can be made.
• the measuring unit is arranged on the cap.
• the measuring unit in particular together with the electronics required for this purpose, is mounted protected on the outside of the cap.
• the cap can be designed with a separate housing that is tight against the environment.
• a third electrode is provided in the apparatus.
• the third electrode z. B. be configured on the tank.
• a return pipe is provided, which is arranged adjacent to the removal tube and forms the third electrode for the measuring unit.
• the return pipe is used in particular urea-water solution that was already removed from the tank and was in the supply lines to the exhaust system, demand-oriented returned to the tank.
• a combination of functions can again be achieved by using the return pipe as a third electrode.
• the materials for such a return pipe reference is made to the comments on the sampling tube and / or the jacket tube.
• the design of the apparatus with three electrodes wherein the third electrode may optionally also be designed as a separate probe, if no return pipe is required, in addition to the determination of the level and possibly also determines the quality of the tank content, so for example, also allows conclusions about the composition of the tank contents.
• the first electrode is used as the reference electrode
• the second electrode as the ground electrode
• the third electrode as the level electrode.
• the measuring unit is connected to all electrodes, in particular, the measurement of the capacitance between different electrodes each allow conclusions about the quality and / or the level.
• Urea solutions used in the automotive sector regularly have a known specific resistance and known dielectric properties.
• the filling level can therefore be determined from capacitances and / or resistances determined between the electrodes.
• the resistance (R) between two uninsulated electrodes, which are arranged in a tank with urea solution at a distance (/), a width (b) and extend perpendicularly over the entire height of the tank, is obtained, for example, approximately according to the following formula in Dependence of the filling level (h) and the specific resistance of the urea solution (p):
• the resistance between the electrodes decreases, while a decreasing level causes an increasing resistance.
• the person skilled in the art can develop formulas adapted to the calculation of the resistance as a function of the filling level on the basis of this formula.
• the first electrode has a first electrode end section and the second electrode has a second ten end portion of the electrode, the first end of the electrode and the second end electrode portion form a space between them and are connected to a voltage source.
• the arrangement of the first electrode and the second electrode takes place in such a way that a free space is created in the end region opposite the cap, which can be flushed around by the tank contents, so that the quality of the composition of the tank contents can be determined hereby. If a voltage is applied between these two electrodes, the resulting measured values are dependent on the composition of the tank contents in the free space. From this, conclusions can be drawn about the proportion of water or urea content in a urea-water solution.
• the second electrode and a third electrode which is arranged parallel to the second electrode, are connected to a voltage source.
• the voltage source may be the same for all three electrodes.
• the second electrode and the third electrode can in this case be used in particular for detecting the filling level, since the tank contents can penetrate into the intermediate space between the second electrode and the third electrode and different voltages are determined by the increasing wetting during filling or the decreasing wetting during emptying can.
• the third electrode ends at the height of the tank or changes its course, at which the reserve area is reached. If necessary, significant changes in the measured value can be detected, which can be used as a signal for a corresponding display.
• a tank for a urea-water solution with an opening for removal of the urea-water solution is proposed, wherein the opening with the cap of the apparatus described herein according to the invention is closable.
• a motor vehicle has a tank mentioned above and a controller which is connected to the measuring unit.
• the controller may be, for example, the engine management of the motor vehicle, which is also set up for the demand-oriented addition of urea-water solution to the exhaust system of the motor vehicle.
• FIG. 1 shows schematically a cross section through a tank 15 with an apparatus 1 according to the invention.
• the tank 15 is a storage vessel for a urea-water solution 16. This tank 15 is also part of a motor vehicle 18, which is shown schematically here is indicated.
• the tank 15 has in the upper region an opening 17 into which a cap 2 is inserted as a closure for the tank 15.
• the tank 15 and the cap 2 are preferably made of plastic, such as polyethylene.
• the cap 2 is in this case penetrated by two tubes, namely once the sampling tube 3 for removing the urea-water solution 16 from the tank 15 out and a return pipe 9, on the withdrawn, but not required urea-water solution 16 back can be directed into the tank 15.
• a jacket tube 4 is formed, which surrounds the removal tube 3 in the interior of the tank 15 substantially completely.
• the jacket tube 4 is arranged at a distance from the removal tube 3.
• an electrically insulating adhesive 8 is provided between the removal tube 3 and the jacket tube 4, the fixed the position of the sampling tube 3 relative to the jacket tube 4 and the components in this section safely against each other electrically isolated.
• a measuring unit 5 which is positioned in particular outside on the cap 2, and a voltage source 14 is now provided. These are both connected to the removal tube 3, the jacket tube 4 and the return tube 9 in such a way that the removal tube 3 functions as the first electrode 6, the jacket tube 4 as the second electrode 7 and the withdrawal tube 9 as the third electrode 10.
• the fill level can be detected, for example, between the third electrode and the second electrode 7 over a wide range of variation of the level of urea-water solution.
• the first electrode 6 and the second electrode 7 on the side facing away from the cap 2 on a first electrode denendabêt 11 and a second electrode end portion 12, which together form an annular space 13 here.
• this region may be additionally provided with the electrode end sections with a concentric shield, for example, to counteract flow fluctuations and the like.
• urea-water solution 16 can penetrate, in which case statements about the quality of the urea-water solution can be obtained via a constant length of the electrode end sections and the measurement.
• the type of measurement, the time of the measurement and / or the evaluation of the measurement can also be initiated or executed via a controller 19 of the motor vehicle 18. In particular, it stands in the exchange of data with the measuring unit and / or operates as required the voltage source 14 for the measurements. LIST OF REFERENCE NUMBERS

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• Physics & Mathematics (AREA)
• Engineering & Computer Science (AREA)
• Chemical & Material Sciences (AREA)
• Thermal Sciences (AREA)
• Fluid Mechanics (AREA)
• Chemical Kinetics & Catalysis (AREA)
• General Physics & Mathematics (AREA)
• Power Engineering (AREA)
• Health & Medical Sciences (AREA)
• Combustion & Propulsion (AREA)
• Mechanical Engineering (AREA)
• General Engineering & Computer Science (AREA)
• Toxicology (AREA)
• Electromagnetism (AREA)
• Exhaust Gas After Treatment (AREA)
• Measurement Of Levels Of Liquids Or Fluent Solid Materials (AREA)

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• 2009
  • 2009-01-16 DE DE102009004936A patent/DE102009004936A1/de not_active Withdrawn
• 2010
  • 2010-01-12 EP EP10700976A patent/EP2387702A1/de not_active Withdrawn
  • 2010-01-12 WO PCT/EP2010/050267 patent/WO2010081796A1/de active Application Filing
  • 2010-01-12 JP JP2011545721A patent/JP2012515338A/ja active Pending
• 2011
  • 2011-07-18 US US13/184,807 patent/US20110309087A1/en not_active Abandoned

Non-Patent Citations (1)

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