EP1858904A1 - Sensor element and sensor containing said element - Google Patents

Sensor element and sensor containing said element

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Publication number
EP1858904A1
EP1858904A1 EP06724910A EP06724910A EP1858904A1 EP 1858904 A1 EP1858904 A1 EP 1858904A1 EP 06724910 A EP06724910 A EP 06724910A EP 06724910 A EP06724910 A EP 06724910A EP 1858904 A1 EP1858904 A1 EP 1858904A1
Authority
EP
European Patent Office
Prior art keywords
sensor
sensor element
measuring electrodes
element according
ceramic
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.)
Withdrawn
Application number
EP06724910A
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German (de)
French (fr)
Inventor
Harald Guenschel
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Robert Bosch GmbH
Original Assignee
Robert Bosch GmbH
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Filing date
Publication date
Application filed by Robert Bosch GmbH filed Critical Robert Bosch GmbH
Publication of EP1858904A1 publication Critical patent/EP1858904A1/en
Withdrawn legal-status Critical Current

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Classifications

    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N15/00—Investigating characteristics of particles; Investigating permeability, pore-volume or surface-area of porous materials
    • G01N15/06—Investigating concentration of particle suspensions
    • G01N15/0656—Investigating concentration of particle suspensions using electric, e.g. electrostatic methods or magnetic methods
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N27/00—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means
    • G01N27/60—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating electrostatic variables, e.g. electrographic flaw testing
    • 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
    • F01N2560/00—Exhaust systems with means for detecting or measuring exhaust gas components or characteristics
    • F01N2560/05—Exhaust systems with means for detecting or measuring exhaust gas components or characteristics the means being a particulate sensor
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02D—CONTROLLING COMBUSTION ENGINES
    • F02D41/00—Electrical control of supply of combustible mixture or its constituents
    • F02D41/02—Circuit arrangements for generating control signals
    • F02D41/14—Introducing closed-loop corrections
    • F02D41/1438—Introducing closed-loop corrections using means for determining characteristics of the combustion gases; Sensors therefor
    • F02D41/1444—Introducing closed-loop corrections using means for determining characteristics of the combustion gases; Sensors therefor characterised by the characteristics of the combustion gases
    • F02D41/1466—Introducing closed-loop corrections using means for determining characteristics of the combustion gases; Sensors therefor characterised by the characteristics of the combustion gases the characteristics being a soot concentration or content

Definitions

  • the invention is based on a sensor element for the determination of particles in gas mixtures, in particular soot sensor, and a sensor containing this according to the type defined in the preamble of the independent claims.
  • Exhaust gas system provided diesel particulate filter be feasible to achieve a high system security and thereby be able to use more cost-effective filter materials.
  • a sensor for the detection of substances in a fluid flow which comprises two spaced measuring electrodes which are exposed to the combustion exhaust gas to be examined.
  • One of the electrodes is connected to a high voltage source, so that a voltage between 1 and 10 kV is applied to the measuring electrodes.
  • Dielectric interference occurs between the measuring electrodes Discharge, wherein the current occurring between the measuring electrodes is correlated with the number of particles present in the gas space between the measuring electrodes.
  • a disadvantage of this type of particle sensors is that their measuring electrodes are exposed relatively unprotected to the gas to be determined and thus both the abrasive or corrosive influences of the gas mixture are exposed and can be affected by soot deposits.
  • Object of the present invention is to provide a sensor for determining the concentration of particles in gas mixtures, which has a long service life and can still be produced inexpensively.
  • the sensor element with the characterizing features of claim 1 has the advantage that it solves the problem underlying the invention in an advantageous manner. This is based in particular on its simple structure and on the use of robust components which have proven themselves in the field of ceramic oxygen sensors. To protect against deterioration of the measuring electrodes by particles depositing, the sensor element has a built-in the sensor element heating element, which is an occasional or regular
  • the sensor body of the sensor element has a recess or an opening to which at least one of the measuring electrodes adjoins.
  • This allows a structure of the sensor element, in which the large surfaces of the at least one measuring electrode is largely covered by ceramic material and thus are removed from corrosive influences of the gas mixture. Only one end face of the measuring electrode adjoins the
  • the sensor element is integrated into a sensor which has an evaluation device which determines the number of dielectric discharges per unit of time and outputs them as a measure of the particle concentration in the gas mixture.
  • one of the measuring electrodes with the heating element is placed on a common ground connection, as this limits the number of required electrical connections of the sensor element.
  • the sensor body of the sensor element is constructed from planar ceramic layers and there are the two measuring electrodes and / or one of the measuring electrodes and the heating element in a layer plane of the sensor body. This embodiment allows a particularly simple construction of the sensor element.
  • FIG. 1 shows schematically the structure of a sensor element according to a first embodiment
  • FIG. 2 shows a variant of the sensor element shown in FIG. 1 and
  • FIG. 3 shows the structure of a sensor element according to a second exemplary embodiment.
  • FIG. 1 shows a basic structure of a first embodiment of the present invention.
  • 10 designates a sensor element for determining particles in a gas mixture surrounding the sensor element, which has, for example, two solid electrolyte layers 11a, 11b.
  • the solid electrolyte layers I Ia, I Ib are carried out as ceramic films and form a planar ceramic body. They consist, for example, of an oxygen-ion-conducting solid electrolyte material, such as Y 2 O 3 stabilized or partially stabilized ZrO 2 . Alternatively, the use of alumina or ceria-containing materials is possible.
  • - A A -
  • Insulating layers 12a, 12b are preferably produced on the solid electrolyte layers 11a, 11b by screen printing of a pasty ceramic material.
  • a pasty ceramic material As the ceramic component of the pasty material, an electrically insulating ceramic material such as, for example, aluminum oxide is preferably used.
  • the integrated shape of the planar ceramic body of the sensor element 10 is produced by laminating together the ceramic films IIa, 11b printed with the insulating layers 12a, 12b and with functional layers, and then sintering the laminated structure in a manner known per se.
  • two measuring electrodes 14, 16 are arranged, which are connected by leads 20, 22 with contact surfaces 24, 26 in contact.
  • the contact surfaces 24, 26 are connected to the leads 20, 22 via plated-through holes through the solid electrolyte layer I Ia and the insulating layer 12a.
  • the measuring electrodes 14, 16 are preferably made of platinum, wherein the electrode material of the measuring electrodes 14, 16 is used in a conventional manner as a cermet to sinter with the ceramic films.
  • a heating element in the form of a resistor track 30 is further provided.
  • the heating element allows the temporary or regular regeneration of the sensor element.
  • the sensor element is heated to a temperature of, for example 600-700 0 C, which allows the burning of deposited particles.
  • the resistance conductor 30 of the heating element is preferably via leads 22, 23 with contact surfaces 26, 27 in contact.
  • the feed line 23 is connected to the contact surface 27 by means of a via through the solid electrolyte layer 11a and the insulation layer 12a.
  • the measuring electrode 16 and the heating element have a common feed line 20 and a common contact surface 26, which is preferably grounded. This allows operation of the sensor element based on only three electrical connections. Alternatively, however, it is also possible to associate the heating element with two separate supply lines or contact surfaces.
  • the electrical resistance conductor 30 of the heating element is preferably made of a cermet material. This is preferably a mixture of a
  • the resistance conductor track can alternatively be designed in the form of a meander. By applying a corresponding heating voltage to the contact surfaces 26, 27, the heating power of the heating element can be regulated accordingly.
  • the sensor element 10 comprises an opening or bore 32, which is preferably formed in a connection remote region of the sensor element and can be round, oval, four- or polygonal. Alternatively, a corresponding recess may be provided.
  • the bore 32 may be, for example, by drilling or punching the laminated sensor element or by pre-drilling or punching the individual
  • Solid electrolyte layers are produced.
  • the drilling can be carried out for example in the form of ultrasonic drilling.
  • At least one of the measuring electrodes 14, 16 adjoins the bore 32; Preferably, both measuring electrodes 14, 16 are in contact with the end face of the bore 32
  • An advantage of this arrangement is that only a very small surface area of the measuring electrodes 14, 16 is exposed to corrosive or abrasive influences of the gas mixture and can effectively be prevented from coking or being adversely affected by soot deposits.
  • a high voltage is applied to the measuring electrodes 14, 16. In this way, electrical discharges occur between the first and second measuring electrodes 14, 16. If the discharge gap located between the measuring electrodes 14, 16, for example, passes through soot particles, this changes the flashover frequency of the electrical discharge. The number of flashovers per
  • Time unit can be detected by an evaluation device, not shown, and correlated with a particle concentration.
  • FIG. 2 shows a variant of the sensor element shown in FIG. 1, wherein the same reference numerals denote the same component components as in FIG. 1.
  • the sensor element depicted in FIG. 2 is designed as a single layer, wherein at least the measuring electrodes 14, 16, the resistance conductor track 30 and the leads 20, 22, 23 are preferably covered by a protective layer, not shown. Furthermore, the resistance conductor 30 of the sensor element is arcuate, so that zones of increased electrical resistance, as they can occur in rectangular areas of the conductor can be avoided.
  • a film made of an electrically insulating ceramic material such as alumina is particularly used as alumina.
  • FIG. 3 shows a second exemplary embodiment of the sensor element illustrated in FIG. 1, wherein the same reference numerals denote the same component components as in FIGS. 1 and 2.
  • the insulating layer 12a is designed so that it ensures electrical insulation of the measuring electrode 16 and the feed line 20 with respect to the solid electrolyte layer I Ia.
  • the insulating layer 12a may cover the solid electrolyte layer 11a, for example, over its entire surface.
  • the sensor element 10 can additionally serve for the determination of gaseous constituents of the gas mixture.
  • the sensor element 10 may, for example, additionally have corresponding further measuring electrodes or reference electrodes. The determination of the oxygen content in the gas mixture is then preferably carried out alternately to determine the

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  • Chemical & Material Sciences (AREA)
  • Analytical Chemistry (AREA)
  • Physics & Mathematics (AREA)
  • Health & Medical Sciences (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Biochemistry (AREA)
  • General Health & Medical Sciences (AREA)
  • General Physics & Mathematics (AREA)
  • Immunology (AREA)
  • Pathology (AREA)
  • Electrochemistry (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Dispersion Chemistry (AREA)
  • Measuring Oxygen Concentration In Cells (AREA)

Abstract

The invention relates to a sensor element for determining particles in gaseous mixtures, in particular for carbon black sensors. The element comprises a ceramic sensor body, into which a heating element is integrated, in addition to a first and second measuring electrode (14, 16), which are situated on ceramic layers (12a, 12b) of the sensor body. According to the invention, a high voltage can be applied between the first and second measuring electrode (14, 16) in such a way that an electric discharge is initiated between said measuring electrodes (14, 16).

Description

01.03.2005 Ket/01.03.2005 Ket /
ROBERT BOSCH GMBH, 70442 StuttgartROBERT BOSCH GMBH, 70442 Stuttgart
Sensorelement und Sensor dieses enthaltendSensor element and sensor containing this
Die Erfindung geht von einem Sensorelement zur Bestimmung von Partikeln in Gasgemischen, insbesondere Rußsensor, und einem Sensor dieses enthaltend gemäß der im Oberbegriff der unabhängigen Ansprüche definierten Art aus.The invention is based on a sensor element for the determination of particles in gas mixtures, in particular soot sensor, and a sensor containing this according to the type defined in the preamble of the independent claims.
Stand der TechnikState of the art
Im Zuge einer sich verschärfenden Umweltgesetzgebung erlangen zunehmend Abgasnachbehandlungssysteme Bedeutung, die die Filtration bzw. Eliminierung von inAs environmental legislation becomes more stringent, exhaust aftertreatment systems are becoming increasingly important, requiring the filtration or elimination of in-situ
Verbrennungsabgasen existierenden Rußpartikeln ermöglichen. Um die Funktionstüchtigkeit derartiger Abgasnachbehandlungssysteme zu überprüfen bzw. zu überwachen, werden Sensoren benötigt, mit denen auch im Langzeitbetrieb eine genaue Ermittlung der aktuell im Verbrennungsabgas vorliegenden Partikelkonzentration ermöglicht werden kann. Darüber hinaus soll mittels derartiger Sensoren eine Beladungsprognose von beispielsweise in einemAllow combustion exhaust gases existing soot particles. In order to check or monitor the functionality of such exhaust aftertreatment systems, sensors are needed with which an accurate determination of the particle concentration currently present in the combustion exhaust gas can be made possible even in long-term operation. In addition, by means of such sensors, a loading prediction of, for example, in a
Abgassystem vorgesehenen Dieselpartikelfiltern durchführbar sein, um eine hohe Systemsicherheit zu erreichen und dadurch kostengünstigere Filtermaterialien einsetzen zu können.Exhaust gas system provided diesel particulate filter be feasible to achieve a high system security and thereby be able to use more cost-effective filter materials.
Aus der DE 102 44 702 Al ist ein Sensor zur Detektion von Stoffen in einem Fluidstrom bekannt, der zwei voneinander beabstandete Messelektroden umfasst, die dem zu untersuchenden Verbrennungsabgas ausgesetzt sind. Eine der Elektroden ist mit einer Hochspannungsquelle verbunden, sodass an den Messelektroden eine Spannung zwischen 1 und 10 kV anliegt. Zwischen den Messelektroden kommt es zu dielektrisch behinderten Entladungen, wobei der zwischen den Messelektroden auftretende Strom mit der Anzahl der im Gasraum zwischen den Messelektroden vorhandenen Partikeln korreliert ist. Nachteilig an dieser Art von Partikelsensoren ist, dass deren Messelektroden relativ ungeschützt dem zu bestimmenden Gas ausgesetzt sind und somit sowohl den abrasiven bzw. korrosiven Einflüssen des Gasgemischs ausgesetzt sind als auch durch Rußablagerungen beeinträchtigt werden können.From DE 102 44 702 Al a sensor for the detection of substances in a fluid flow is known, which comprises two spaced measuring electrodes which are exposed to the combustion exhaust gas to be examined. One of the electrodes is connected to a high voltage source, so that a voltage between 1 and 10 kV is applied to the measuring electrodes. Dielectric interference occurs between the measuring electrodes Discharge, wherein the current occurring between the measuring electrodes is correlated with the number of particles present in the gas space between the measuring electrodes. A disadvantage of this type of particle sensors is that their measuring electrodes are exposed relatively unprotected to the gas to be determined and thus both the abrasive or corrosive influences of the gas mixture are exposed and can be affected by soot deposits.
Aufgabe der vorliegenden Erfindung ist es, einen Sensor zur Bestimmung der Konzentration von Partikeln in Gasgemischen bereitzustellen, der eine hohe Lebensdauer aufweist und dennoch kostengünstig hergestellt werden kann.Object of the present invention is to provide a sensor for determining the concentration of particles in gas mixtures, which has a long service life and can still be produced inexpensively.
Vorteile der ErfindungAdvantages of the invention
Das Sensorelement mit den kennzeichnenden Merkmalen des Anspruchs 1 hat den Vorteil, dass es die der Erfindung zugrundeliegende Aufgabe in vorteilhafter Weise löst. Dies beruht insbesondere auf dessen einfachem Aufbau und auf der Verwendung robuster Bauelemente, die sich im Bereich keramischer Sauerstoffsensoren bewährt haben. Zum Schutz vor einer Beeinträchtigung der Messelektroden durch sich ablagernde Partikel weist das Sensorelement ein in das Sensorelement integriertes Heizelement auf, das eine gelegentliche oder regelmäßigeThe sensor element with the characterizing features of claim 1 has the advantage that it solves the problem underlying the invention in an advantageous manner. This is based in particular on its simple structure and on the use of robust components which have proven themselves in the field of ceramic oxygen sensors. To protect against deterioration of the measuring electrodes by particles depositing, the sensor element has a built-in the sensor element heating element, which is an occasional or regular
Regenerierung des Sensorelementes insbesondere durch Abbrand der Partikel ermöglicht.Regeneration of the sensor element in particular by burning of the particles allows.
Weitere vorteilhafte Ausführungsformen des vorliegenden Sensors ergeben sich aus den Unteransprüchen.Further advantageous embodiments of the present sensor will become apparent from the dependent claims.
So ist es von Vorteil, wenn der Sensorkörper des Sensorelementes eine Aussparung oder einen Durchbruch aufweist, an die mindestens eine der Messelektroden grenzt. Dies ermöglicht einen Aufbau des Sensorelementes, bei dem die Großflächen der mindestens einen Messelektrode weitgehend von keramischem Material bedeckt ist und somit korrosiven Einflüssen des Gasgemisches entzogen sind. Lediglich eine Stirnseite der Messelektrode grenzt an dieThus, it is advantageous if the sensor body of the sensor element has a recess or an opening to which at least one of the measuring electrodes adjoins. This allows a structure of the sensor element, in which the large surfaces of the at least one measuring electrode is largely covered by ceramic material and thus are removed from corrosive influences of the gas mixture. Only one end face of the measuring electrode adjoins the
Aussparung bzw. den Durchbruch und gewährleistet eine zuverlässige Bestimmung der Partikel im Gasgemisch. Weiterhin ist von Vorteil, wenn das Sensorelement in einen Sensor integriert ist, der eine Auswertungsvorrichtung aufweist, die die Anzahl der dielektrischen Entladungen pro Zeiteinheit ermittelt und diese als Maß für die Partikelkonzentration im Gasgemisch ausgibt.Recess or breakthrough and ensures reliable determination of the particles in the gas mixture. Furthermore, it is advantageous if the sensor element is integrated into a sensor which has an evaluation device which determines the number of dielectric discharges per unit of time and outputs them as a measure of the particle concentration in the gas mixture.
Es ist besonders vorteilhaft, wenn eine der Messelektroden mit dem Heizelement auf einen gemeinsamen Masseanschluss gelegt ist, da dies die Zahl der nötigen elektrischen Anschlüsse des Sensorelementes begrenzt.It is particularly advantageous if one of the measuring electrodes with the heating element is placed on a common ground connection, as this limits the number of required electrical connections of the sensor element.
In einer besonders vorteilhaften Ausführungsform ist der Sensorkörper des Sensorelementes aus planaren keramischen Schichten aufgebaut und es befinden sich die beiden Messelektroden und/oder eine der Messelektroden und das Heizelement in einer Schichtebene des Sensorkörpers. Diese Ausführungsform ermöglicht einen besonders einfachen Aufbau des Sensorelementes.In a particularly advantageous embodiment, the sensor body of the sensor element is constructed from planar ceramic layers and there are the two measuring electrodes and / or one of the measuring electrodes and the heating element in a layer plane of the sensor body. This embodiment allows a particularly simple construction of the sensor element.
Zeichnungdrawing
Zwei Ausführungsbeispiele des erfindungsgemäßen Sensorelementes sind in der Zeichnung dargestellt und werden in der nachfolgenden Beschreibung näher erläutert. Dabei zeigt Figur 1 schematisch den Aufbau eines Sensorelementes gemäß einem ersten Ausführungsbeispiel, FigurTwo embodiments of the sensor element according to the invention are shown in the drawing and are explained in more detail in the following description. 1 shows schematically the structure of a sensor element according to a first embodiment, FIG
2 eine Variante des in Figur 1 dargestellten Sensorelementes und Figur 3 den Aufbau eines Sensorelementes gemäß einem zweiten Ausführungsbeispiel.2 shows a variant of the sensor element shown in FIG. 1 and FIG. 3 shows the structure of a sensor element according to a second exemplary embodiment.
Beschreibung der AusführungsbeispieleDescription of the embodiments
In Figur 1 ist ein prinzipieller Aufbau einer ersten Ausführungsform der vorliegenden Erfindung dargestellt. Mit 10 ist ein Sensorelement zur Bestimmung von Partikeln in einem das Sensorelement umgebenden Gasgemisch bezeichnet, das beispielsweise zwei Festelektrolytschichten I Ia, 1 Ib aufweist. Die Festelektrolytschichten I Ia, 1 Ib werden dabei als keramische Folien ausgeführt und bilden einen planaren keramischen Körper. Sie bestehen beispielsweise aus einem sauerstoffionenleitenden Festelektrolytmaterial, wie mit Y2O3 stabilisiertem oder teilstabilisiertem ZrO2. Alternativ ist auch die Verwendung von Aluminiumoxid- oder Cerdioxid-haltigen Materialien möglich. - A -FIG. 1 shows a basic structure of a first embodiment of the present invention. 10 designates a sensor element for determining particles in a gas mixture surrounding the sensor element, which has, for example, two solid electrolyte layers 11a, 11b. The solid electrolyte layers I Ia, I Ib are carried out as ceramic films and form a planar ceramic body. They consist, for example, of an oxygen-ion-conducting solid electrolyte material, such as Y 2 O 3 stabilized or partially stabilized ZrO 2 . Alternatively, the use of alumina or ceria-containing materials is possible. - A -
Auf den Festelektrolytschichten I Ia, 1 Ib werden vorzugsweise Isolationsschichten 12a, 12b mittels Siebdruck eines pastösen keramischen Materials erzeugt. Als keramische Komponente des pastösen Materials wird dabei bevorzugt ein elektrisch isolierendes keramisches Material wie beispielsweise Aluminiumoxid verwendet.Insulating layers 12a, 12b are preferably produced on the solid electrolyte layers 11a, 11b by screen printing of a pasty ceramic material. As the ceramic component of the pasty material, an electrically insulating ceramic material such as, for example, aluminum oxide is preferably used.
Die integrierte Form des planaren keramischen Körpers des Sensorelements 10 wird durch Zusammenlaminieren der mit den Isolationsschichten 12a, 12b und mit Funktionsschichten bedruckten keramischen Folien IIa, 1 Ib und anschließendem Sintern der laminierten Struktur in an sich bekannter Weise hergestellt.The integrated shape of the planar ceramic body of the sensor element 10 is produced by laminating together the ceramic films IIa, 11b printed with the insulating layers 12a, 12b and with functional layers, and then sintering the laminated structure in a manner known per se.
Auf der der Festelektrolytschicht I Ia zugewandten Großfläche der Isolationsschicht 12b sind zwei Messelektroden 14, 16 angeordnet, die durch Zuleitungen 20, 22 mit Kontaktflächen 24, 26 in Kontakt stehen. Dazu sind die Kontaktflächen 24, 26 mit den Zuleitungen 20, 22 über Durchkontaktierungen durch die Festelektrolytschicht I Ia und die Isolationsschicht 12a hindurch verbunden.On the solid electrolyte layer I Ia facing large surface of the insulating layer 12b, two measuring electrodes 14, 16 are arranged, which are connected by leads 20, 22 with contact surfaces 24, 26 in contact. For this purpose, the contact surfaces 24, 26 are connected to the leads 20, 22 via plated-through holes through the solid electrolyte layer I Ia and the insulating layer 12a.
An die Messelektroden 14, 16 kann eine Hochspannung insbesondere von 1 bis 10 kV angelegt werden. Dabei sind die Messelektroden 14, 16 vorzugsweise aus Platin ausgeführt, wobei das Elektrodenmaterial der Messelektroden 14, 16 in an sich bekannter Weise als Cermet eingesetzt wird, um mit den keramischen Folien zu versintern.To the measuring electrodes 14, 16, a high voltage, in particular from 1 to 10 kV can be applied. The measuring electrodes 14, 16 are preferably made of platinum, wherein the electrode material of the measuring electrodes 14, 16 is used in a conventional manner as a cermet to sinter with the ceramic films.
Auf der der Festelektrolytschicht I Ia zugewandten Großfläche der Isolationsschicht 12b ist weiterhin ein Heizelement in Form einer Widerstandsleiterbahn 30 vorgesehen. Das Heizelement ermöglicht die zeitweilige oder regelmäßige Regenerierung des Sensorelementes.On the solid electrolyte layer I Ia facing large surface of the insulating layer 12b, a heating element in the form of a resistor track 30 is further provided. The heating element allows the temporary or regular regeneration of the sensor element.
Dabei wird das Sensorelement auf eine Temperatur von beispielsweise 600 - 700 0C aufgeheizt, die den Abbrand von abgelagerten Partikeln ermöglicht.In this case, the sensor element is heated to a temperature of, for example 600-700 0 C, which allows the burning of deposited particles.
Die Widerstandleiterbahn 30 des Heizelementes steht vorzugsweise über Zuleitungen 22, 23 mit Kontaktflächen 26, 27 in Kontakt. Dabei ist die Zuleitung 23 mittels einer Durchkontaktierung durch die Festelektrolytschicht I Ia und die Isolationsschicht 12a hindurch mit der Kontaktfläche 27 verbunden. Im Rahmen dieser Ausführungsform weisen die Messelektrode 16 und das Heizelement eine gemeinsame Zuleitung 20 und eine gemeinsame Kontaktfläche 26 auf, die vorzugsweise auf Masse gelegt ist. Dies ermöglicht einen Betrieb des Sensorelementes auf der Basis von nur drei elektrischen Anschlüssen. Alternativ ist es jedoch auch möglich, dem Heizelement zwei separate Zuleitungen bzw. Kontaktflächen zuzuordnen.The resistance conductor 30 of the heating element is preferably via leads 22, 23 with contact surfaces 26, 27 in contact. In this case, the feed line 23 is connected to the contact surface 27 by means of a via through the solid electrolyte layer 11a and the insulation layer 12a. In the context of this embodiment, the measuring electrode 16 and the heating element have a common feed line 20 and a common contact surface 26, which is preferably grounded. This allows operation of the sensor element based on only three electrical connections. Alternatively, however, it is also possible to associate the heating element with two separate supply lines or contact surfaces.
Die elektrische Widerstandsleiterbahn 30 des Heizelementes wird vorzugsweise aus einem Cermet-Material ausgeführt. Dabei handelt es sich vorzugsweise um eine Mischung einesThe electrical resistance conductor 30 of the heating element is preferably made of a cermet material. This is preferably a mixture of a
Metalls, wie beispielsweise Platin, mit keramischen Anteilen, wie beispielsweise Aluminiumoxid. Die Widerstandsleiterbahn kann alternativ in Form eines Mäanders ausgeführt werden. Durch Anlegen einer entsprechenden Heizspannung an die Kontaktflächen 26, 27 kann die Heizleistung des Heizelementes entsprechend reguliert werden.Metal, such as platinum, with ceramic moieties, such as alumina. The resistance conductor track can alternatively be designed in the form of a meander. By applying a corresponding heating voltage to the contact surfaces 26, 27, the heating power of the heating element can be regulated accordingly.
Weiterhin umfasst das Sensorelement 10 eine Durchbrechung oder Bohrung 32, die vorzugsweise in einem anschlussfernen Bereich des Sensorelementes ausgebildet ist und rund, oval, vier- oder mehreckig ausgeführt sein kann. Alternativ kann eine entsprechende Aussparung vorgesehen sein. Die Bohrung 32 kann beispielsweise durch Bohren oder Stanzen des laminierten Sensorelementes oder durch Vorbohren bzw. -stanzen der einzelnenFurthermore, the sensor element 10 comprises an opening or bore 32, which is preferably formed in a connection remote region of the sensor element and can be round, oval, four- or polygonal. Alternatively, a corresponding recess may be provided. The bore 32 may be, for example, by drilling or punching the laminated sensor element or by pre-drilling or punching the individual
Festelektrolytschichten erzeugt werden. Das Bohren kann beispielsweise in Form eines Ultraschallbohrens vorgenommen werden.Solid electrolyte layers are produced. The drilling can be carried out for example in the form of ultrasonic drilling.
An die Bohrung 32 grenzt mindestens eine der Messelektroden 14, 16; vorzugsweise stehen beide Messelektroden 14, 16 stirnseitig in Kontakt mit dem die Bohrung 32 durchströmendenAt least one of the measuring electrodes 14, 16 adjoins the bore 32; Preferably, both measuring electrodes 14, 16 are in contact with the end face of the bore 32
Gasgemisch. Ein Vorteil dieser Anordnung ist, dass nur ein sehr geringer Oberflächenbereich der Messelektroden 14, 16 korrosiven bzw. abrasiven Einflüssen des Gasgemisches ausgesetzt ist und einer Verkokung bzw. Beeinträchtigung derselben durch Rußablagerungen wirksam vorgebeugt werden kann.Gas mixture. An advantage of this arrangement is that only a very small surface area of the measuring electrodes 14, 16 is exposed to corrosive or abrasive influences of the gas mixture and can effectively be prevented from coking or being adversely affected by soot deposits.
Während des Betriebs des Sensorelementes 10 wird an die Messelektroden 14, 16 eine Hochspannung angelegt. Auf diese Weise kommt es zu elektrischen Entladungen zwischen der ersten und zweiten Messelektrode 14, 16. Wird die sich zwischen den Messelektroden 14, 16 befindende Entladungsstrecke beispielsweise von Rußpartikeln durchflogen, so verändert dies die Überschlagfrequenz der elektrischen Entladung. Die Zahl der erfolgten Überschläge proDuring operation of the sensor element 10, a high voltage is applied to the measuring electrodes 14, 16. In this way, electrical discharges occur between the first and second measuring electrodes 14, 16. If the discharge gap located between the measuring electrodes 14, 16, for example, passes through soot particles, this changes the flashover frequency of the electrical discharge. The number of flashovers per
Zeiteinheit kann durch eine nicht dargestellte Auswertungsvorrichtung erfasst und mit einer Partikelkonzentration korreliert werden.Time unit can be detected by an evaluation device, not shown, and correlated with a particle concentration.
In Figur 2 ist eine Variante des in Figur 1 dargestellten Sensorelementes dargestellt, wobei gleiche Bezugszeichen gleiche Bauteilkomponenten bezeichnen wie in Figur 1. Das in Figur 2 abgebildete Sensorelement ist einschichtig ausgeführt, wobei zumindest die Messelektroden 14, 16, die Widerstandsleiterbahn 30 und die Zuleitungen 20, 22, 23 vorzugsweise mit einer nicht dargestellten Schutzschicht bedeckt sind. Weiterhin ist die Widerstandsleiterbahn 30 des Sensorelementes bogenförmig ausgeführt, sodass Zonen erhöhten elektrischen Widerstandes, wie sie in rechtwinkligen Bereichen der Leiterbahn auftreten können, vermieden werden. Als Grundmaterial des einschichtigen Substrats 12c wird insbesondere eine Folie aus einem elektrisch isolierenden keramischen Material wie Aluminiumoxid verwendet.FIG. 2 shows a variant of the sensor element shown in FIG. 1, wherein the same reference numerals denote the same component components as in FIG. 1. The sensor element depicted in FIG. 2 is designed as a single layer, wherein at least the measuring electrodes 14, 16, the resistance conductor track 30 and the leads 20, 22, 23 are preferably covered by a protective layer, not shown. Furthermore, the resistance conductor 30 of the sensor element is arcuate, so that zones of increased electrical resistance, as they can occur in rectangular areas of the conductor can be avoided. As a base material of the single-layered substrate 12c, a film made of an electrically insulating ceramic material such as alumina is particularly used.
In Figur 3 ist ein zweites Ausführungsbeispiel des in Figur 1 dargestellten Sensorelementes dargestellt, wobei gleiche Bezugszeichen gleiche Bauteilkomponenten bezeichnen wie in den Figuren 1 und 2.FIG. 3 shows a second exemplary embodiment of the sensor element illustrated in FIG. 1, wherein the same reference numerals denote the same component components as in FIGS. 1 and 2.
Dabei ist eine der Messelektroden 16 und deren Zuleitung 20 auf einer Großfläche desIn this case, one of the measuring electrodes 16 and the supply line 20 on a large surface of the
Sensorelementes angeordnet. Dazu wird die Isolationsschicht 12a so gestaltet, dass sie eine elektrische Isolation der Messelektrode 16 und der Zuleitung 20 gegenüber der Festelektrolytschicht I Ia gewährleistet. Die Isolationsschicht 12a kann die Festelektrolytschicht I Ia beispielsweise vollflächig bedecken.Sensor element arranged. For this purpose, the insulating layer 12a is designed so that it ensures electrical insulation of the measuring electrode 16 and the feed line 20 with respect to the solid electrolyte layer I Ia. The insulating layer 12a may cover the solid electrolyte layer 11a, for example, over its entire surface.
Das Sensorelement 10 kann neben der Bestimmung der Konzentration von Partikeln in Gasgemischen zusätzlich der Bestimmung von gasförmigen Bestandteilen des Gasgemischs dienen. Dazu kann das Sensorelement 10 bspw. zusätzlich entsprechende weitere Messelektroden bzw. Referenzelektroden aufweisen. Die Bestimmung des Sauerstoffgehaltes im Gasgemisch erfolgt dann vorzugsweise alternierend zur Bestimmung derIn addition to the determination of the concentration of particles in gas mixtures, the sensor element 10 can additionally serve for the determination of gaseous constituents of the gas mixture. For this purpose, the sensor element 10 may, for example, additionally have corresponding further measuring electrodes or reference electrodes. The determination of the oxygen content in the gas mixture is then preferably carried out alternately to determine the
Partikelkonzentration im Gasgemisch. Dabei wird in einem ersten Zeitraum eine Hochspannung an die Messelektroden 14, 16 angelegt und so die Konzentration an Partikeln im Gasgemisch bestimmt, und in einem zweiten Zeitraum die an die Messelektroden 14, 16 angelegte Hochspannung ausgeschaltet und bspw. die sich zwischen der weiteren Messelektrode und der Referenzelektrode ausbildendePotentialdifferenz bestimmt. Auf diese Weise wird eineParticle concentration in the gas mixture. In this case, in a first period of time a high voltage is applied to the measuring electrodes 14, 16 and the concentration of particles in the gas mixture is determined, and in a second period the high voltage applied to the measuring electrodes 14, 16 is switched off and, for example, between the further measuring electrode and determines the reference electrode forming potential difference. That way, one becomes
Einkopplung der an die Messelektroden angelegte Hochspannung in das Messsignal der durch die weitere Messelektrode und die Referenzelektrode gebildete Nernstzelle vermieden. Coupling of the voltage applied to the measuring electrodes high voltage in the measuring signal of the Nernst cell formed by the other measuring electrode and the reference electrode avoided.

Claims

01.03.2005 Ket/ROBERT BOSCH GMBH, 70442 StuttgartSensorelement und Sensor dieses enthaltendAnsprüche 01.03.2005 Ket / ROBERT BOSCH GMBH, 70442 Stuttgart Sensor element and sensor containing this claim
1. Sensorelement zur Bestimmung von Partikeln in Gasgemischen, insbesondere für Rußsensoren, mit einem keramischen Sensorkörper, in den ein Heizelement integriert ist, und mit einer ersten und einer zweiten Messelektrode (14, 16), die auf keramischen Schichten (12a, 12b) des Sensorkörpers angeordnet sind, wobei zwischen erster und zweiter Messelektrode (14, 16) eine Hochspannung anlegbar ist, derart, dass es zu einer elektrischen Entladung zwischen den Messelektroden (14, 16) kommt.Anspruch [en] A sensor element for determining particles in gas mixtures, in particular for soot sensors, comprising a ceramic sensor body in which a heating element is integrated, and having first and second measuring electrodes (14,16) mounted on ceramic layers (12a, 12b) of the Sensor body are arranged, wherein between the first and second measuring electrode (14, 16), a high voltage can be applied, such that there is an electrical discharge between the measuring electrodes (14, 16).
2. Sensorelement nach Anspruch 1, dadurch gekennzeichnet, dass der Sensorkörper eine Aussparung oder einen Durchbruch (32) aufweist, an den mindestens eine der2. Sensor element according to claim 1, characterized in that the sensor body has a recess or an opening (32), to which at least one of
Messelektroden (14, 16) grenzt.Measuring electrodes (14, 16) borders.
3. Sensorelement nach Anspruch 1 oder 2, dadurch gekennzeichnet, dass der keramische Sensorkörper Zirkondioxid, Aluminiumoxid und/oder Erdalkalioxide enthält.3. Sensor element according to claim 1 or 2, characterized in that the ceramic sensor body contains zirconium dioxide, alumina and / or alkaline earth oxides.
4. Sensorelement nach einem der vorhergehenden Ansprüche, dadurch gekennzeichnet, dass eine der Messelektroden (14, 16) mit dem Heizelement auf einen gemeinsamen Masseanschluss (26) gelegt ist.4. Sensor element according to one of the preceding claims, characterized in that one of the measuring electrodes (14, 16) is placed with the heating element on a common ground terminal (26).
5. Sensorelement nach einem der vorhergehenden Ansprüche, dadurch gekennzeichnet, dass der Sensorkörper aus planaren keramischen Schichten (1 Ia, 1 Ib, 12a, 12b) aufgebaut ist.5. Sensor element according to one of the preceding claims, characterized in that the sensor body of planar ceramic layers (1 Ia, 1 Ib, 12a, 12b) is constructed.
6. Sensorelement nach Anspruch 5, dadurch gekennzeichnet, dass sich die beiden Messelektroden (14, 16) in einer Schichtebene (12b) des Sensorkörpers befinden. 6. Sensor element according to claim 5, characterized in that the two measuring electrodes (14, 16) are located in a layer plane (12b) of the sensor body.
7. Sensorelement nach Anspruch 5, dadurch gekennzeichnet, dass sich mindestens eine der Messelektroden (14, 16) und das Heizelement in einer Schichtebene (12b) des Sensorkörpers befinden.7. Sensor element according to claim 5, characterized in that at least one of the measuring electrodes (14, 16) and the heating element are in a layer plane (12b) of the sensor body.
8. Sensorelement nach einem der vorhergehenden Ansprüche, dadurch gekennzeichnet, dass die Großflächen mindestens einer der Messelektroden (14, 16) weitgehend von keramischem Material bedeckt sind.8. Sensor element according to one of the preceding claims, characterized in that the large areas of at least one of the measuring electrodes (14, 16) are largely covered by ceramic material.
9. Sensor enthaltend ein Sensorelement nach einem der vorhergehenden Ansprüche, dadurch gekennzeichnet, dass eine Auswertevorrichtung vorgesehen ist, die die Anzahl der zwischen den Messelektroden (14, 16) auftretenden Entladungen pro Zeiteinheit ermittelt und dies als Maß für die Partikelkonzentration im Gasgemisch ausgibt. 9. Sensor comprising a sensor element according to one of the preceding claims, characterized in that an evaluation device is provided which determines the number of times between the measuring electrodes (14, 16) discharges per unit time and outputs this as a measure of the particle concentration in the gas mixture.
EP06724910A 2005-03-07 2006-03-02 Sensor element and sensor containing said element Withdrawn EP1858904A1 (en)

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TWI404924B (en) 2005-08-26 2013-08-11 Semiconductor Energy Lab Particle detection sensor, method for manufacturing particle detection sensor, and method for detecting particle using particle detection sensor
JP5219710B2 (en) * 2008-09-25 2013-06-26 日本碍子株式会社 Particulate matter detection device and manufacturing method thereof
JP5164896B2 (en) * 2009-03-12 2013-03-21 日本碍子株式会社 Particulate matter detector
JP2010210535A (en) * 2009-03-12 2010-09-24 Ngk Insulators Ltd Granular substance detector
JP2010210534A (en) * 2009-03-12 2010-09-24 Ngk Insulators Ltd Particulate matter detector
JP2010210533A (en) * 2009-03-12 2010-09-24 Ngk Insulators Ltd Particulate matter detector
WO2017090434A1 (en) * 2015-11-25 2017-06-01 京セラ株式会社 Sensor substrate and sensor device
DE102017216046A1 (en) * 2017-09-12 2019-03-14 Robert Bosch Gmbh Particle sensor with a planar, isolated corona discharge electrode
CN111141799A (en) * 2020-02-19 2020-05-12 浙江百岸科技有限公司 Chip of nitrogen-oxygen sensor

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