EP0781410A1 - Sensor for gas concentration measurement - Google Patents

Sensor for gas concentration measurement

Info

Publication number
EP0781410A1
EP0781410A1 EP96922042A EP96922042A EP0781410A1 EP 0781410 A1 EP0781410 A1 EP 0781410A1 EP 96922042 A EP96922042 A EP 96922042A EP 96922042 A EP96922042 A EP 96922042A EP 0781410 A1 EP0781410 A1 EP 0781410A1
Authority
EP
European Patent Office
Prior art keywords
tube
sensor
housing
contact
gas
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Withdrawn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
EP96922042A
Other languages
German (de)
French (fr)
Inventor
Guido Gustaaf Antoon Cappa
Peter Van Geloven
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.)
Heraeus Electro Nite International NV
Original Assignee
Heraeus Electro Nite International NV
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority claimed from DE19534918A external-priority patent/DE19534918C2/en
Application filed by Heraeus Electro Nite International NV filed Critical Heraeus Electro Nite International NV
Publication of EP0781410A1 publication Critical patent/EP0781410A1/en
Withdrawn legal-status Critical Current

Links

Classifications

    • 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
    • G01N27/26—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating electrochemical variables; by using electrolysis or electrophoresis
    • G01N27/403—Cells and electrode assemblies
    • G01N27/406—Cells and probes with solid electrolytes
    • G01N27/407—Cells and probes with solid electrolytes for investigating or analysing gases
    • 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
    • G01N27/26—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating electrochemical variables; by using electrolysis or electrophoresis
    • G01N27/403—Cells and electrode assemblies
    • G01N27/406—Cells and probes with solid electrolytes
    • G01N27/407—Cells and probes with solid electrolytes for investigating or analysing gases
    • G01N27/4078—Means for sealing the sensor element in a housing

Definitions

  • the invention relates to a sensor for measuring gas concentrations in a gas mixture with a tube closed on one side, on the outside of which an electrical sensor contact is arranged along the tube and whose end opposite the closed end is arranged in a housing, one running around the tube Intermediate space between the housing and the tube is closed in a gas-tight manner.
  • Such a gas sensor is known from US-A-3960693.
  • a tube with a catalytically active layer is closed at its end facing the gas to be measured and open at its other end. It is thickened at this open end and held in a housing.
  • This housing is screwed into a wall opening of the room with the gas to be measured, for example in internal combustion engines.
  • the inside of the tube is connected to the ambient atmosphere, the reference gas.
  • a gap between the housing and the tube is sealed within the housing, so that the two different gases are separated from one another.
  • the seal is made of a metal ring, as is commonly used for example in spark plugs. Gas measurements of this type are usually carried out at high temperatures (from around 150 ° C, in internal combustion engines from around 500 ° C).
  • the housing which is made of metal because of the required temperature resistance, is thus conductively connected to the tube, that is to say the sensor contact.
  • the housing is integrated in the measuring circuit; the sensor is a so-called mono sensor. Since the seal is located in a region of the sensor arrangement which is heated very strongly during the measurement of a fuel gas, the different expansion coefficients of the housing and tube can lead to leaks and thus to measurement inaccuracies, since the seal has the different Can not compensate for expansion with certainty.
  • the electrical contacting of the sensor contact is also located in this hot zone and can therefore only be implemented with a high degree of security and with considerable effort, since the contact materials tend to oxidize at the high operating temperatures.
  • the hot contact of the seal with the tube which can usually be formed from a solid electrolyte, causes a parasitic voltage, the size of which varies greatly over time, because the slow oxidation or reduction of the seal is uncontrollable. As a result, the drift of the sensor characteristics is considerably deteriorated.
  • a similar sensor is also known from EP-AO 520 528.
  • EP-A-0 398 579 Another type of gas sensor is known from EP-A-0 398 579.
  • a flat sensor element is arranged within a cylindrical metal housing, ceramic powder for fixing and sealing being arranged between the sensor and the housing. Due to the different geometries between the sensor element and the housing and due to the different expansion coefficients of the materials, leaks can also occur when heated. Sealing to the gas space to be measured is particularly problematic. Apart from this, the sensor element can easily be damaged by vibrations occurring during operation.
  • the invention is based on the object of specifying a sensor of the generic type which ensures a reliable seal between the gas to be measured and the reference gas to be measured even at high operating temperatures and in which at the same time several sensor contacts, which are electrically insulated from the housing, can be implemented and in which no parasitic voltages arise which impair the drift characteristics of the sensor.
  • the object for a sensor according to the preamble of claim 1 is achieved in that a gas-tight seal running around between the housing and the tube at the end opposite the closed end, which forms a cold end (or a cold region) of the tube, it is arranged that at least one electrical sensor contact is arranged in an electrically insulated manner from the housing on the outside of the tube and that the at least one sensor contact at the closed end opposite end of the tube opens and is connected to an electrical line.
  • the cold end or the cold area of the tube is the area which is arranged outside the room with the gas to be measured and which is far enough from the room with the gas to be measured so that it heats up at most only slightly so that the seal to be preferably used made of an electrically insulating, elastic material is not destroyed and retains its elasticity.
  • the specific necessary distance can be easily determined by a few tests or measurements.
  • the contacting of the sensor contacts with further electrical lines also takes place; Here, high-temperature oxidation phenomena on the contacts are avoided.
  • Different coefficients of expansion of the materials used play practically no role here, in particular with elastic seals, there are practically no thermal stresses, so that a high sealing effect can be achieved.
  • a plurality of sensor contacts are arranged on the outer surface of the tube, it being possible for one or more sensor contacts to be designed as a heating contact. This avoids the use of a separate radiator which is pushed into the tube in known arrangements. This increases the heater's efficiency and reaction speed.
  • At least one electrical contact can expediently be arranged on the inside of the tube.
  • the tube is cylindrical and is therefore very easy to manufacture.
  • it can be advantageous to apply an electrically insulating layer on the tube between the housing and the sensor contacts.
  • at least a part of the outer surface of the tube has a solid electrolyte material that is electrical with at least one sensor contact connected is. It is also possible to form the entire tube from a solid electrolyte material.
  • at least part of the outer surface of the tube to have a material whose electrical resistance depends on the gas concentration. In order to effectively cool the cold area, it is expedient that cooling fins are arranged on the outside of the housing.
  • Figure 1 shows the tube of the sensor with sensor contacts
  • Figure 2 shows a cross section through the sensor
  • FIG. 3 shows the schematic representation of the sensor
  • Figure 4 shows a further cross section through the sensor
  • Figure 5 shows the structure of some assembly elements.
  • Figure 1 shows the tube 1 of the sensor.
  • the tube 1 is cylindrical and closed at one end. It is made from an electrically insulating material, for example aluminum oxide, or from a solid electrolyte material, for example zirconium dioxide. It can also be made of another material that has electrical insulation on its outside.
  • Gas sensors 2 are arranged on the outside of the tube 1 as active elements. Furthermore, an electric heater 3 is placed on the tube 1. On these electrical sensor contacts, namely the gas sensors 2 and the heater 3, a thin, electrically insulating layer 4 is attached, which is, however, gas-permeable and which prevents the gas sensors 2 from becoming dirty. B. prevent exhaust gas components.
  • the electrical sensor contacts 2; 3 arranged along the tube 1 open into so-called external electrodes 5 on the open side of the tube 1, to which the tube 1 is electrically contacted.
  • a contact ring 6 is arranged on the end face of the open end of the tube 1 and serves to contact an electrical contact 7 arranged on the inside of the tube 1.
  • This electrical contact 7 is necessary if the gas sensor 2 is an electrochemical sensor with reference gas.
  • the reference gas is located inside the tube 1 and is, for example, equal to the ambient air.
  • the tube 1 is arranged in the housing 8 shown in Figure 2.
  • the housing 8 has at its tip, in which the closed end of the tube 1 is located, gas openings 9 through which the gas to be measured reaches the gas sensors 2.
  • the housing 8 In the area of the closed end of the tube 1, the housing 8 has a nut 10 with an external thread 11, with the aid of which the sensor is screwed into the wall of the room with the gas to be measured. In the area of internal combustion engines, this space can, for example, be part of the exhaust system (for example, of cars). A seal 12 can also be arranged on the nut 10.
  • the closed end of the tube 1 abuts the corresponding end of the housing 8 and is pressed against this end by a spring 13.
  • the tube 1 is arranged at a distance from the wall of the housing 8 so that the electrical sensor contacts (gas sensors 2 and heater 3) have no electrical contact with the housing 8.
  • An O-ring 14 made of an elastic and heat-resistant plastic, for example made of Teflon or Viton, is provided as the gas seal.
  • This O-ring 14 serves as a seal of the gas space of the gas to be measured against the atmosphere surrounding the housing 8, so that, for example, the ambient air remains separated from the exhaust gases of an engine.
  • the O-ring 14 also realizes a stable position of the tube 1 within the housing 8 and ensures the electrical insulation of the tube 1 or the sensor contacts 2, 3 from the housing 8.
  • the O-ring 14 prevents the transmission of vibrations from the housing 8 onto the tube 1 and it compensates for different coefficients of expansion between the tube 1 and the housing 8, so that no thermal stresses can occur even with slight heating.
  • Another O-ring 15 serves to contact the outer electrodes 5 with the connecting wires 16.
  • the O-ring 15 is also made of an elastic, heat-resistant plastic. By means of this O-ring 15, the connecting wires 16 are reliably pressed against the outer electrodes 5, so that a reliable contact is guaranteed. It is also possible for the connecting wires 16 to be welded to the outer electrodes 5 or for the outer electrodes 5 to be contacted by a plug which is pushed onto the tube 1 and provided with connecting wires 16.
  • the O-ring 15 is pressed against the O-ring 14 by the pressure piece 17, so that the tube 1 is held securely within the housing 8 by the additional tension generated thereby.
  • the contact piece 17 is pressed against the O-rings 14, 15 by means of the nut 18 via the washer 19 (made of a heat-resistant plastic), the O-ring 14 being pressed against a stop surface of the housing 8.
  • the mother 18 serves to close the Inner part of the housing 8; the connecting wires 16 and the connecting wire 20 are passed through them.
  • the connecting wires 16, 20 are centered by the disk 19 and passed through the pressure piece 17 into the interior of the housing.
  • the connecting wire 20 After assembly, the connecting wire 20 has an electrical contact with the spring 13, which in turn rests on the contact ring 6 in an electrically conductive manner, so that the connecting wire 20 contacts the electrical contact 7 in the interior of the tube 1.
  • the arrangement of pressure piece 17, nut 18 and washer 20 is enlarged in Figure 5 and shown in several views.
  • plastic seals as O-rings 14, 15 with the resulting advantages described above is possible in a region of the housing 8 which does not heat up significantly even at the operating temperature of the sensor, that is to say is only heated to such an extent that the plastic seals do not lose their elasticity.
  • this area is at least approximately 2 cm, in particular approximately 4 to 6 cm, from the seal 12, which closes the space of the gas to be measured.
  • the O-rings 14; 15 are usually arranged in an area in which the temperature is only so high that the materials of the O-rings 14; 15 can be used permanently.
  • 8 cooling fins 21 are arranged on the outside of the housing.
  • the distance between the rings 14, 15 and the closed end of the tube 1 can be reduced under certain circumstances.
  • the number and shape of the cooling fins 21 as well as the length of the housing 8 can be selected as a function of the operating temperature of the gas to be measured, in order to ensure that the so-called cold end of the tube 1, on which the O-rings 14, 15 are arranged, warmed up only slightly so that the O-rings 14, 15 are not damaged and lose their function.
  • FIGS. 3 and 4 show a longitudinal section through the sensor that differs somewhat from FIG. 2.
  • the sensor according to the invention has a very simple and therefore inexpensive structure; With the possibility of accommodating several sensors in one and the same housing, it is not very susceptible to faults and is therefore safe to use.

Abstract

The invention relates to a sensor for measuring gas concentrations in a gas mixture, with a tube closed at one end, along the outside of which is fitted an electric sensor contact and the open end of which is fitted in a housing, where the space along the tube between it and the housing is gastightly sealed. In order to ensure a reliable seal between the gas to be measured and the reference gas, even at high operating temperatures, and at the same time to provide several sensor funtions with high contact reliability, there are a gastight seal running peripherally between the housing and the tube at the open end of the tube forming a cold end and at least one electric sensor contact electrically insulated from the housing on the outside of the tube, and the at least one sensor contact opens into the open end of the tube and is connected to an electric line.

Description

Sensor zur Messung von Gaskonzentrationen Sensor for measuring gas concentrations
Die Erfindung betrifft einen Sensor zur Messung von Gaskonzentrationen in einem Gasgemisch mit einem einseitig geschlossenen Röhrchen, an dessen Außenseite längs des Röhrchens ein elektrischer Sensorkontakt angeordnet ist und dessen dem geschlossenen Ende gegenüberlie¬ gendes Ende in einem Gehäuse angeordnet ist, wobei ein um das Röhrchen laufender Zwi¬ schenraum zwischen Gehäuse und Röhrchen gasdicht geschlossen ist.The invention relates to a sensor for measuring gas concentrations in a gas mixture with a tube closed on one side, on the outside of which an electrical sensor contact is arranged along the tube and whose end opposite the closed end is arranged in a housing, one running around the tube Intermediate space between the housing and the tube is closed in a gas-tight manner.
Ein derartiger Gassensor ist aus der US-A-3960693 bekannt. Ein Röhrchen mit einer kataly¬ tisch wirkenden Schicht ist an seinem dem zu messenden Gas zugewandten Ende geschlos¬ sen und an seinem anderen Ende offen. An diesem offenen Ende ist es verdickt ausgebildet und in einem Gehäuse gehaltert. Dieses Gehäuses wird in eine Wandöffnung des Raumes mit dem zu messenden Gas eingeschraubt, beispielsweise in Verbrennungskraftmaschinen. Das Innere des Röhrchens steht mit der Umgebungsatmosphäre, dem Referenzgas, in Verbindung. Innerhalb des Gehäuses ist ein Spalt zwischen Gehäuse und Röhrchen abgedichtet, so daß die beiden unterschiedlichen Gase voneinander getrennt sind. Die Dichtung ist aus einem Metall¬ ring hergestellt, wie er allgemein üblich beispielsweise auch bei Zündkerzen eingesetzt wird. Gasmessungen dieser Art werden in der Regel bei hohen Temperaturen (ab etwa 150°C, bei Verbrennungskraftmaschinen ab etwa 500°C) durchgeführt. Das Gehäuse, das wegen der er¬ forderlichen Temperaturbeständigkeit aus Metall gebildet ist, ist also leitend mit dem Röhrchen, also dem Sensorkontakt verbunden. Das heißt, daß das Gehäuse in den Meßkreis integriert ist; der Sensor ist ein sogenannter Monosensor. Da die Dichtung sich in einem Bereich der Sen¬ soranordnung befindet, die während der Messung eines Brenngases sehr stark erhitzt wird, können die unterschiedlichen Ausdehnungskoeffizienten von Gehäuse und Röhrchen zu Lecka¬ gen und damit zu Meßungenauigkeiten führen, da die Dichtung die unterschiedlichen Ausdehnungen nicht mit Sicherheit ausgleichen kann. Auch die elektrische Kontaktierung des Sensorkontaktes befindet sich in dieser heißen Zone und ist deshalb nur mit erheblichem Auf¬ wand in hoher Sicherheit realisierbar, da die Kontaktmaterialien bei den hohen Einsatztempera¬ turen zur Oxidation neigen. Außerdem verursacht der heiße Kontakt der Dichtung mit dem Röhrchen, das üblicherweise aus einem Festelektrolyten gebildet sein kann, eine parasitäre Spannung, deren Größe mit der Zeit stark variiert, weil die langsame Oxidation oder Reduktion der Dichtung unkontrollierbar ist. Die Drift der Sensorcharakteristiken werden dadurch erheblich verschlechtert. Ein ähnlicher Sensor ist auch aus der EP-A-O 520 528 bekannt.Such a gas sensor is known from US-A-3960693. A tube with a catalytically active layer is closed at its end facing the gas to be measured and open at its other end. It is thickened at this open end and held in a housing. This housing is screwed into a wall opening of the room with the gas to be measured, for example in internal combustion engines. The inside of the tube is connected to the ambient atmosphere, the reference gas. A gap between the housing and the tube is sealed within the housing, so that the two different gases are separated from one another. The seal is made of a metal ring, as is commonly used for example in spark plugs. Gas measurements of this type are usually carried out at high temperatures (from around 150 ° C, in internal combustion engines from around 500 ° C). The housing, which is made of metal because of the required temperature resistance, is thus conductively connected to the tube, that is to say the sensor contact. This means that the housing is integrated in the measuring circuit; the sensor is a so-called mono sensor. Since the seal is located in a region of the sensor arrangement which is heated very strongly during the measurement of a fuel gas, the different expansion coefficients of the housing and tube can lead to leaks and thus to measurement inaccuracies, since the seal has the different Can not compensate for expansion with certainty. The electrical contacting of the sensor contact is also located in this hot zone and can therefore only be implemented with a high degree of security and with considerable effort, since the contact materials tend to oxidize at the high operating temperatures. In addition, the hot contact of the seal with the tube, which can usually be formed from a solid electrolyte, causes a parasitic voltage, the size of which varies greatly over time, because the slow oxidation or reduction of the seal is uncontrollable. As a result, the drift of the sensor characteristics is considerably deteriorated. A similar sensor is also known from EP-AO 520 528.
Eine etwas andere Anordnung ist aus US-A-3399233 als galvanische Festelektrolytzelle be¬ kannt. Auch hier ist das Metallgehäuse in den Meßkreis integriert. Eine Gasdichtung ist hier nicht notwendig, da die Messung zwischen zwei Flüssigkeiten stattfindet.A somewhat different arrangement is known from US-A-3399233 as a galvanic solid electrolyte cell. Here, too, the metal housing is integrated in the measuring circuit. A gas seal is not necessary here, since the measurement takes place between two liquids.
Ein Gassensor einer anderen Art ist aus EP-A-O 398 579 bekannt. Hier ist ein ebenes Sensore¬ lement innerhalb eines zylindrischen Metallgehäuses angeordnet, wobei zwischen Sensor und Gehäuse Keramikpulver zur Fixierung und Abdichtung angeordnet ist. Aufgrund der unter¬ schiedlichen Geometrien zwischen Sensorelement und Gehäuse und aufgrund der unterschied¬ lichen Ausdehnungskoeffizienten der Materialien können auch hier Leckagen bei Erwärmung entstehen. Insbesondere die Abdichtung zu dem zu messenden Gasraum hin ist problematisch. Abgesehen davon, kann das Sensorelement durch während des Betriebes auftretende Vibratio¬ nen leicht beschädigt werden.Another type of gas sensor is known from EP-A-0 398 579. Here, a flat sensor element is arranged within a cylindrical metal housing, ceramic powder for fixing and sealing being arranged between the sensor and the housing. Due to the different geometries between the sensor element and the housing and due to the different expansion coefficients of the materials, leaks can also occur when heated. Sealing to the gas space to be measured is particularly problematic. Apart from this, the sensor element can easily be damaged by vibrations occurring during operation.
Ausgehend von dem vorstehend beschriebenen Stand der Technik liegt der Erfindung die Auf¬ gabe zugrunde, einen Sensor der gattungsgemäßen Art anzugeben, der auch bei hohen Be¬ triebstemperaturen eine zuverlässige Abdichtung zwischen zu messendem Gas und Referenz¬ gas gewährleistet und bei dem gleichzeitig mehrere Sensorkontakte, die elektrisch vom Gehäu¬ se isoliert sind, realisiert werden können, und bei dem keine parasitären Spannungen entste¬ hen, die die Driftcharakteristiken des Sensors verschlechtern.On the basis of the prior art described above, the invention is based on the object of specifying a sensor of the generic type which ensures a reliable seal between the gas to be measured and the reference gas to be measured even at high operating temperatures and in which at the same time several sensor contacts, which are electrically insulated from the housing, can be implemented and in which no parasitic voltages arise which impair the drift characteristics of the sensor.
Erfindungsgemäß wird die Aufgabe für einen Sensor gemäß dem Oberbegriff des Anspruchs 1 dadurch gelöst, daß eine zwischen Gehäuse und Röhrchen umlaufende gasdichte Dichtung an dem dem geschlossenen Ende gegenüberliegenden Ende, das ein kaltes Ende (bzw. einen kal¬ ten Bereich) des Röhrchens bildet, angeordnet ist, daß an der Außenseite des Röhrchens min¬ destens ein elektrischer Sensorkontakt von dem Gehäuse elektrisch isoliert angeordnet ist und daß der mindestens eine Sensorkontakt an dem dem geschlossenen Ende gegenüberliegenden Ende des Röhrchens mündet und mit einer elektrischen Leitung verbun¬ den ist. Das kalte Ende bzw. der kalte Bereich des Röhrchens ist der Bereich, der außerhalb des Raumes mit dem zu messenden Gas angeordnet ist und der weit genug von dem Raum mit dem zu messenden Gas entfernt ist, so daß er sich höchstens geringfügig erwärmt, so daß die vorzugsweise einzusetzende Dichtung aus einem elektrisch isolierenden, elastischen Mate¬ rial nicht zerstört wird und ihre Elastizität behält. Die konkrete notwendige Entfernung ist durch wenige Versuche bzw. Messungen leicht zu ermitteln. In einem derartigen kalten Bereich findet auch die Kontaktierung der Sensorkontakte mit weiterführenden elektrischen Leitungen statt; hier werden hochtemperaturbedingte Oxidationserscheinungen an den Kontakten vermieden. Unterschiedliche Ausdehnungskoeffizienten der verwendeten Materialien spielen hier praktisch keine Rolle, insbesondere bei elastischen Dichtungen entstehen praktisch keine thermischen Spannungen, so daß eine hohe Dichtwirkung erreicht werden kann. Außerdem werden parasi¬ täre elektrochemische Spannungen, die im Kontaktbereich zwischen üblichen metallischen Dichtungen, die sich im heißen Bereich befinden, und dem Festelektrolyten (dem Röhrchen) entstehen, durch den Einsatz elektrisch isolierender Dichtungen im kalten Bereich vermieden. Desweiteren hat sich gezeigt, daß Vibrationen, wie sie während des Betriebs von Kraftfahr¬ zeugmotoren bzw. deren Abgasanlagen auftreten, nicht auf den Sensor übertragen werden, so daß eine hohe Störsicherheit des Sensor erreicht wird. Zweckmäßigerweise können die elektri¬ schen Leitungen an die Sensorkontakte geschweißt oder gelötet bzw. mit Hilfe eines elasti¬ schen Ringes an den bzw. die Sensorkontakte angepreßt werden. Dadurch sind zuverlässige Kontaktierungen einfach zu realisieren.According to the invention, the object for a sensor according to the preamble of claim 1 is achieved in that a gas-tight seal running around between the housing and the tube at the end opposite the closed end, which forms a cold end (or a cold region) of the tube, it is arranged that at least one electrical sensor contact is arranged in an electrically insulated manner from the housing on the outside of the tube and that the at least one sensor contact at the closed end opposite end of the tube opens and is connected to an electrical line. The cold end or the cold area of the tube is the area which is arranged outside the room with the gas to be measured and which is far enough from the room with the gas to be measured so that it heats up at most only slightly so that the seal to be preferably used made of an electrically insulating, elastic material is not destroyed and retains its elasticity. The specific necessary distance can be easily determined by a few tests or measurements. In such a cold area, the contacting of the sensor contacts with further electrical lines also takes place; Here, high-temperature oxidation phenomena on the contacts are avoided. Different coefficients of expansion of the materials used play practically no role here, in particular with elastic seals, there are practically no thermal stresses, so that a high sealing effect can be achieved. In addition, parasitic electrochemical voltages, which arise in the contact area between conventional metallic seals, which are located in the hot area, and the solid electrolyte (the tube), are avoided by using electrically insulating seals in the cold area. Furthermore, it has been shown that vibrations, such as occur during the operation of motor vehicle engines or their exhaust systems, are not transmitted to the sensor, so that a high level of interference immunity of the sensor is achieved. The electrical lines can expediently be welded or soldered to the sensor contacts or pressed onto the sensor contact (s) with the aid of an elastic ring. This makes reliable contacting easy to implement.
Vorteilhafterweise sind an der Außenfläche des Röhrchens mehrere Sensorkontakte angeord¬ net, wobei ein oder mehrere Sensorkontakte als Heizkontakt ausgebildet werden können. Da¬ durch wird der Einsatz eines separaten Heizkörpers, der in bekannten Anordnungen in das Röhrchen geschoben wird, vermieden. Dadurch werden Wirkungsgrad und Reaktionsgeschwin¬ digkeit des Heizers erhöht.Advantageously, a plurality of sensor contacts are arranged on the outer surface of the tube, it being possible for one or more sensor contacts to be designed as a heating contact. This avoids the use of a separate radiator which is pushed into the tube in known arrangements. This increases the heater's efficiency and reaction speed.
Zweckmäßigerweise kann an der Innenseite des Röhrchens mindestens ein elektrischer Kon¬ takt angeordnet sein. In einer vorteilhaften Ausgestaltung der Erfindung ist das Röhrchen zylin¬ derförmig ausgebildet und dadurch sehr leicht zu fertigen. Weiterhin kann es vorteilhaft sein, zwischen Gehäuse und Sensorkontakten eine elektrisch isolierende Schicht auf dem Röhrchen anzubringen. Weiterhin ist es möglich, das mindestens ein Teil der Außenfläche des Röhrchens ein Festelektrolytmaterial aufweist, das mit mindestens einem Sensorkontakt elektrisch verbunden ist. Es ist auch möglich, das gesamte Röhrchen aus einem Festelektrolytmaterial zu bilden. Es ist ebenfalls möglich, daß mindestens ein Teil der Außenoberfläche des Röhrchens ein Material aufweist, dessen elektrischer Widerstand von der Gaskonzentration abhängt. Um den kalten Bereich effektiv zu kühlen ist es zweckmäßig, daß an der Außenseite des Gehäuses Kühlrippen angeordnet sind.At least one electrical contact can expediently be arranged on the inside of the tube. In an advantageous embodiment of the invention, the tube is cylindrical and is therefore very easy to manufacture. Furthermore, it can be advantageous to apply an electrically insulating layer on the tube between the housing and the sensor contacts. Furthermore, it is possible that at least a part of the outer surface of the tube has a solid electrolyte material that is electrical with at least one sensor contact connected is. It is also possible to form the entire tube from a solid electrolyte material. It is also possible for at least part of the outer surface of the tube to have a material whose electrical resistance depends on the gas concentration. In order to effectively cool the cold area, it is expedient that cooling fins are arranged on the outside of the housing.
Im folgenden wird die Erfindung beispielhaft anhand einer Zeichnung erläutert.In the following the invention is explained by way of example with reference to a drawing.
In der Zeichnung zeigt:The drawing shows:
Figur 1 das Röhrchen des Sensors mit SensorkontaktenFigure 1 shows the tube of the sensor with sensor contacts
Figur 2 einen Querschnitt durch den SensorsFigure 2 shows a cross section through the sensor
Figur 3 die schematische Darstellung des SensorsFigure 3 shows the schematic representation of the sensor
Figur 4 einen weiteren Querschnitt durch den Sensor undFigure 4 shows a further cross section through the sensor and
Figur 5 den Aufbau einiger Montageelemente.Figure 5 shows the structure of some assembly elements.
Figur 1 zeigt das Röhrchen 1 des Sensors. Das Röhrchen 1 ist zylindrisch ausgebildet und an seinem einen Ende geschlossen. Es ist aus einem elektrisch isolierenden Material, zum Bei¬ spiel Aluminiumoxid oder aus einem Festelektrolytmaterial, zum Beispiel Zirkondioxid herge¬ stellt. Es kann auch aus einem anderen Material, das an seiner Außenseite eine elektrische Isolierung aufweist, gebildet sind. Auf der Außenseite des Röhrchens 1 sind Gassensoren 2 als aktive Elemente angeordnet. Desweiteren ist ein elektrischer Heizer 3 auf das Röhrchen 1 auf¬ gebracht. Auf diesen elektrischen Sensorkontakten, nämlich den Gassensoren 2 und dem Hei¬ zer 3 ist eine dünne, elektrisch isolierende Schicht 4 angebracht, die jedoch gasdurchlässig ist, und die die Verschmutzung der Gassensoren 2 z. B. durch Abgasbestandteile verhindern. Die längs des Röhrchens 1 angeordneten elektrischen Sensorkontakte 2;3 münden an der offenen Seite des Röhrchens 1 in sogenannte Außenelektroden 5, an denen das Röhrchen 1 elektrisch kontaktiert wird. An der Stirnseite des offenen Endes des Röhrchens 1 ist ein Kontaktring 6 an¬ geordnet, der der Kontaktierung eines an der Innenseite des Röhrchens 1 angeordneten elektri¬ schen Kontaktes 7 dient. Dieser elektrische Kontakt 7 ist notwendig, wenn der Gassensor 2 ein elektrochemischer Sensor mit Referenzgas ist. Das Referenzgas befindet sich in diesem Fall im Inneren des Röhrchens 1 und ist beispielsweise gleich der Umgebungsluft. Das Röhrchen 1 ist in dem in Figur 2 dargestellten Gehäuse 8 angeordnet. Das Gehäuse 8 weist an seiner Spitze, in der sich das geschlossene Ende des Röhrchens 1 befindet, Gasöffnungen 9 auf, durch die das zu messende Gas an die Gassensoren 2 gelangt. Das Gehäuse 8 weist im Bereich des ge¬ schlossenen Endes des Röhrchens 1 eine Mutter 10 mit einem Außengewinde 11 auf, mit de¬ ren Hilfe der Sensor in die Wand des Raumes mit dem zu messenden Gas eingeschraubt wird. Dieser Raum kann im Bereich von Verbrennungskraftmaschinen beispielsweise ein Teil der Auspuffanlage (zum Beispiel von PKWs) sein. An der Mutter 10 kann noch eine Dichtung 12 angeordnet sein.Figure 1 shows the tube 1 of the sensor. The tube 1 is cylindrical and closed at one end. It is made from an electrically insulating material, for example aluminum oxide, or from a solid electrolyte material, for example zirconium dioxide. It can also be made of another material that has electrical insulation on its outside. Gas sensors 2 are arranged on the outside of the tube 1 as active elements. Furthermore, an electric heater 3 is placed on the tube 1. On these electrical sensor contacts, namely the gas sensors 2 and the heater 3, a thin, electrically insulating layer 4 is attached, which is, however, gas-permeable and which prevents the gas sensors 2 from becoming dirty. B. prevent exhaust gas components. The electrical sensor contacts 2; 3 arranged along the tube 1 open into so-called external electrodes 5 on the open side of the tube 1, to which the tube 1 is electrically contacted. A contact ring 6 is arranged on the end face of the open end of the tube 1 and serves to contact an electrical contact 7 arranged on the inside of the tube 1. This electrical contact 7 is necessary if the gas sensor 2 is an electrochemical sensor with reference gas. In this case, the reference gas is located inside the tube 1 and is, for example, equal to the ambient air. The tube 1 is arranged in the housing 8 shown in Figure 2. The housing 8 has at its tip, in which the closed end of the tube 1 is located, gas openings 9 through which the gas to be measured reaches the gas sensors 2. In the area of the closed end of the tube 1, the housing 8 has a nut 10 with an external thread 11, with the aid of which the sensor is screwed into the wall of the room with the gas to be measured. In the area of internal combustion engines, this space can, for example, be part of the exhaust system (for example, of cars). A seal 12 can also be arranged on the nut 10.
Das Röhrchen 1 liegt mit seinem geschlossenen Ende stirnseitig an dem entsprechenden Ende des Gehäuses 8 an und wird durch eine Feder 13 an dieses Ende gepreßt. Das Röhrchen 1 ist beabstandet von der Wand des Gehäuses 8 angeordnet, so daß die elektrischen Sensorkon¬ takte (Gassensoren 2 und Heizer 3) keinen elektrischen Kontakt mit dem Gehäuse 8 haben. Als Gasdichtung ist ein O-Ring 14 aus einem elastischen und wärmeständigen Kunststoff vor¬ gesehen, beispielsweise aus Teflon oder Viton. Dieser O-Ring 14 dient als Dichtung des Gas¬ raumes des zu messenden Gases gegen die das Gehäuse 8 umgebende Atmosphäre, so daß beispielsweise die Umgebungsluft von den Abgasen eines Motors getrennt bleibt. Der O-Ring 14 realisiert des weiteren eine stabile Lage des Röhrchens 1 innerhalb des Gehäuses 8 und sichert die elektrische Isolation des Röhrchens 1 bzw. der Sensorkontakte 2,3 von dem Gehäuse 8. Desweiteren verhindert der O-Ring 14 die Übertragung von Vibrationen von dem Gehäuse 8 auf das Röhrchen 1 und er gleicht unterschiedliche Ausdehnungskoefizienten zwi¬ schen Röhrchen 1 und Gehäuse 8 aus, so daß auch bei geringfügiger Erwärmung keine thermi¬ schen Spannungen auftreten können. Ein weiterer O-Ring 15 dient der Kontaktierung der Au¬ ßenelektroden 5 mit den Anschlußdrähten 16. Auch O-Ring 15 ist aus einem elastischen, wär¬ mebeständigen Kunststoff gefertigt. Mittels dieses O-Ringes 15 werden die Anschlußdrähte 16 zuverlässig an die Außenelektroden 5 angepreßt, so daß ein zuverlässiger Kontakt gewährlei¬ stet ist. Es ist auch möglich, daß die Anschlußdrähte 16 an die Außenelektroden 5 ange¬ schweißt werden oder daß die Außenelektrode 5 durch einen auf das Röhrchen 1 geschobenen und mit Anschlußdrähten 16 versehenen Stecker kontaktiert werden.The closed end of the tube 1 abuts the corresponding end of the housing 8 and is pressed against this end by a spring 13. The tube 1 is arranged at a distance from the wall of the housing 8 so that the electrical sensor contacts (gas sensors 2 and heater 3) have no electrical contact with the housing 8. An O-ring 14 made of an elastic and heat-resistant plastic, for example made of Teflon or Viton, is provided as the gas seal. This O-ring 14 serves as a seal of the gas space of the gas to be measured against the atmosphere surrounding the housing 8, so that, for example, the ambient air remains separated from the exhaust gases of an engine. The O-ring 14 also realizes a stable position of the tube 1 within the housing 8 and ensures the electrical insulation of the tube 1 or the sensor contacts 2, 3 from the housing 8. Furthermore, the O-ring 14 prevents the transmission of vibrations from the housing 8 onto the tube 1 and it compensates for different coefficients of expansion between the tube 1 and the housing 8, so that no thermal stresses can occur even with slight heating. Another O-ring 15 serves to contact the outer electrodes 5 with the connecting wires 16. The O-ring 15 is also made of an elastic, heat-resistant plastic. By means of this O-ring 15, the connecting wires 16 are reliably pressed against the outer electrodes 5, so that a reliable contact is guaranteed. It is also possible for the connecting wires 16 to be welded to the outer electrodes 5 or for the outer electrodes 5 to be contacted by a plug which is pushed onto the tube 1 and provided with connecting wires 16.
Durch das Anpreßstück 17 wird der O-Ring 15 gegen den O-Ring 14 gedrückt, so daß dieser durch die dadurch erzeugte zusätzliche Spannung das Röhrchen 1 sicher innerhalb des Ge¬ häuses 8 hält. Das Anpreßstück 17 wird mittels der Mutter 18 über die Scheibe 19 (aus einem wärmeständigen Kunststoff) gegen die O-Ringe 14,15 gedrückt, wobei der O-Ring 14 gegen ei¬ ne Anschlagfläche des Gehäuses 8 gedrückt wird. Die Mutter 18 dient dem Verschluß des Innenteils des Gehäuses 8; durch sie werden die Anschlußdrähte 16 sowie der Anschlußdraht 20 hindurchgeführt. Die Anschlußdrähte 16,20 werden von der Scheibe 19 zentriert und durch das Anpreßstück 17 in das Innere des Gehäuses geführt. Anschlußdraht 20 weist nach der Montage einen elektrischen Kontakt zu der Feder 13 auf, die wiederum an dem Kontaktring 6 elektrisch leitend anliegt, so daß der Anschlußdraht 20 den elektrischen Kontakt 7 im Inneren des Röhrchens 1 kontaktiert. Die Anordnung aus Anpreßstück 17, Mutter 18 und Scheibe 20 ist in Figur 5 vergrößert und in mehreren Ansichten dargestellt.The O-ring 15 is pressed against the O-ring 14 by the pressure piece 17, so that the tube 1 is held securely within the housing 8 by the additional tension generated thereby. The contact piece 17 is pressed against the O-rings 14, 15 by means of the nut 18 via the washer 19 (made of a heat-resistant plastic), the O-ring 14 being pressed against a stop surface of the housing 8. The mother 18 serves to close the Inner part of the housing 8; the connecting wires 16 and the connecting wire 20 are passed through them. The connecting wires 16, 20 are centered by the disk 19 and passed through the pressure piece 17 into the interior of the housing. After assembly, the connecting wire 20 has an electrical contact with the spring 13, which in turn rests on the contact ring 6 in an electrically conductive manner, so that the connecting wire 20 contacts the electrical contact 7 in the interior of the tube 1. The arrangement of pressure piece 17, nut 18 and washer 20 is enlarged in Figure 5 and shown in several views.
Der Einsatz von Kunststoffdichtungen als O-Ringe 14,15 mit den daraus resultierenden oben beschriebenen Vorteilen ist in einem solchen Bereich des Gehäuses 8 möglich, der sich auch bei Betriebstemperatur des Sensors nicht wesentlich aufheizt, das heißt nur so stark erwärmt wird, daß die Kunststoffdichtungen ihre Elastizität nicht verlieren. Dieser Bereich ist, abhängig von der Temperatur des zu messenden Gases mindestens etwa 2 cm, insbesondere etwa 4 bis 6 cm von der Dichtung 12 entfernt, die den Raum des zu messenden Gases abschließt. Die O- Ringe 14; 15 sind in der Regel in einem Bereich angeordnet, in dem die Temperatur nur so hoch ist, daß die Materialien der O-Ringe 14; 15 dauerhaft verwendet werden können. Um den Küh¬ leffekt zu erhöhen, sind an der Außenseite des Gehäuses 8 Kühlrippen 21 angeordnet. Da¬ durch kann unter Umständen der Abstand zwischen den Ringen 14;15 und dem geschlossenen Ende des Röhrchens 1 verringert werden. Zahl und Form der Kühlrippen 21 können ebenso wie die Länge des Gehäuses 8 in Abhängigkeit von der Betriebstemperatur des zu messenden Ga¬ ses gewählt werden, um zu sichern, daß das sogenannte kalte Ende des Röhrchens 1 , an dem die O-Ringe 14,15 angeordnet sind, sich nur geringfügig soweit erwärmt, daß die O-Ringe 14,15 nicht beschädigt werden und ihre Funktion verlieren.The use of plastic seals as O-rings 14, 15 with the resulting advantages described above is possible in a region of the housing 8 which does not heat up significantly even at the operating temperature of the sensor, that is to say is only heated to such an extent that the plastic seals do not lose their elasticity. Depending on the temperature of the gas to be measured, this area is at least approximately 2 cm, in particular approximately 4 to 6 cm, from the seal 12, which closes the space of the gas to be measured. The O-rings 14; 15 are usually arranged in an area in which the temperature is only so high that the materials of the O-rings 14; 15 can be used permanently. In order to increase the cooling effect, 8 cooling fins 21 are arranged on the outside of the housing. As a result, the distance between the rings 14, 15 and the closed end of the tube 1 can be reduced under certain circumstances. The number and shape of the cooling fins 21 as well as the length of the housing 8 can be selected as a function of the operating temperature of the gas to be measured, in order to ensure that the so-called cold end of the tube 1, on which the O-rings 14, 15 are arranged, warmed up only slightly so that the O-rings 14, 15 are not damaged and lose their function.
Die Anordnung der Kühlrippen wird auch in den Figuren 3 und 4 gezeigt, wobei Figur 4 einen von Figur 2 etwas abweichenden Längsschnitt durch den Sensor darstellt.The arrangement of the cooling fins is also shown in FIGS. 3 and 4, wherein FIG. 4 shows a longitudinal section through the sensor that differs somewhat from FIG. 2.
Der erfindungsgemäße Sensor weist einen sehr einfachen und damit kostengünstigen Aufbau auf; er ist bei der Möglichkeit, mehrere Sensoren in ein und demselben Gehäuse unterzubrin¬ gen, wenig störanfällig und daher sicher in der Handhabung. The sensor according to the invention has a very simple and therefore inexpensive structure; With the possibility of accommodating several sensors in one and the same housing, it is not very susceptible to faults and is therefore safe to use.

Claims

Patentansprüche Claims
1. Sensor zur Messung von Gaskonzentrationen in einem Gasgemisch mit einem einseitig geschlossenen Röhrchen, an dessen Außenseite längs des Röhrchens ein elektrischer Sensorkontakt angeordnet ist und dessen dem geschlossenen Ende gegenüberliegendes Ende in einem Gehäuse angeordnet ist, wobei ein um das Röhrchen laufender Zwischen¬ raum zwischen Gehäuse und Röhrchen gasdicht geschlossen ist, dadurch gekennzeich¬ net, daß eine zwischen Gehäuse (8) und Röhrchen (1) umlaufende, gasdichte Dichtung (14) an dem dem geschlossenen Ende gegenüberliegenden Ende, das ein kal¬ tes Ende des Röhrchens (1) bildet, angeordnet ist, daß an der Außenseite des Röhrchens (1) mindestens ein elektrischer Sensorkontakt (2;3) von dem Gehäuse (8) elektrisch isoliert angeordnet ist und daß der mindestens eine Sensorkontakt (2;3) an dem dem geschlossenen Ende gegenüberliegenden Ende des Röhrchens (1) mündet und mit einer elektrischen Leitung (16) verbunden ist.1.Sensor for measuring gas concentrations in a gas mixture with a tube closed on one side, on the outside of which an electrical sensor contact is arranged along the tube and whose end opposite the closed end is arranged in a housing, with an intermediate space running around the tube between Housing and tube is closed in a gas-tight manner, characterized in that a gas-tight seal (14) running around between the housing (8) and tube (1) at the end opposite the closed end, which has a cold end of the tube (1) forms, is arranged that on the outside of the tube (1) at least one electrical sensor contact (2; 3) from the housing (8) is arranged electrically isolated and that the at least one sensor contact (2; 3) at the opposite end of the closed End of the tube (1) opens and is connected to an electrical line (16).
2. Sensor nach Anspruch 1 , dadurch gekennzeichnet, daß die zwischen Röhrchen (1) und Gehäuse (8) um das Röhrchen (1) laufende Dichtung (14) aus einem elektrisch isolieren¬ den, elastischen Material besteht.2. Sensor according to claim 1, characterized in that between the tube (1) and housing (8) around the tube (1) running seal (14) consists of an electrically isolating elastic material.
3. Sensor nach Anspruch 1 oder 2, dadurch gekennzeichnet, daß die elektrische Leitung (16) mittels eines elastischen Ringes (15) an den Sensorkontakt (2;3) angepreßt ist. 3. Sensor according to claim 1 or 2, characterized in that the electrical line (16) by means of an elastic ring (15) to the sensor contact (2; 3) is pressed.
4. Sensor nach Anspruch 1 oder 2, dadurch gekennzeichnet, daß die elektrische Leitung (16) an den Sensorkontakt (2;3) angeschweißt ist.4. Sensor according to claim 1 or 2, characterized in that the electrical line (16) to the sensor contact (2; 3) is welded.
5. Sensor nach einem der Ansrüche 1 bis 4, dadurch gekennzeichnet, daß an der Außenflä¬ che des Röhrchens (1) mehrere Sensorkontakte (2;3) angeordnet sind, wobei mindestens ein Sensorkontakt als Heizkontakt (3) ausgebildet ist.5. Sensor according to one of claims 1 to 4, characterized in that a plurality of sensor contacts (2; 3) are arranged on the outer surface of the tube (1), at least one sensor contact being designed as a heating contact (3).
6. Sensor nach einem der Ansprüche 1 bis 5, dadurch gekennzeichnet, daß an der Innen¬ seite des Röhrchens (1) mindestens ein elektrischer Kontakt (7) angeordnet ist.6. Sensor according to one of claims 1 to 5, characterized in that at least one electrical contact (7) is arranged on the inner side of the tube (1).
7. Sensor nach einem der Ansprüche 1 bis 6, dadurch gekennzeichnet, daß das Röhrchen (1) zylinderförmig ausgebildet ist.7. Sensor according to one of claims 1 to 6, characterized in that the tube (1) is cylindrical.
8. Sensor nach einem der Ansprüche 1 bis 7, dadurch gekennzeichnet, daß zwischen Ge¬ häuse (8) und Sensorkontakten (2;3) eine elektrisch isolierende Schicht (4) auf dem Röhrchen (1) angebracht ist.8. Sensor according to one of claims 1 to 7, characterized in that between the Ge housing (8) and sensor contacts (2; 3) an electrically insulating layer (4) is attached to the tube (1).
9. Sensor nach einem der Ansprüche 1 bis 8, dadurch gekennzeichnet, daß mindestens ein Teil der Außenfläche des Röhrchens (1) ein Festelektrolytmaterial aufweist, das mit min¬ destens einem Sensorkontakt (2) verbunden ist.9. Sensor according to one of claims 1 to 8, characterized in that at least part of the outer surface of the tube (1) has a solid electrolyte material which is connected to at least one sensor contact (2).
10. Sensor nach einem der Ansprüche 1 bis 8, dadurch gekennzeichnet, daß das gesamte Röhrchen (1) aus einem Festelektrolytmaterial gebildet ist, das mit mindestens einem Sensorkontakt (2) verbunden ist.10. Sensor according to one of claims 1 to 8, characterized in that the entire tube (1) is formed from a solid electrolyte material which is connected to at least one sensor contact (2).
11. Sensor nach einem der Ansprüche 1 bis 8, dadurch gekennzeichnet, daß mindestens ein Teil der Außenoberfläche des Röhrchens (1) ein Material aufweist, dessen elektrischer Widerstand von der Gaskonzentration abhängt.11. Sensor according to one of claims 1 to 8, characterized in that at least a part of the outer surface of the tube (1) comprises a material whose electrical resistance depends on the gas concentration.
12. Sensor nach einem der Ansprüche 1 bis 11 , dadurch gekennzeichnet, daß an der Außen¬ seite des Gehäuses (8) Kühlrippen (21) angeordnet sind. 12. Sensor according to one of claims 1 to 11, characterized in that cooling fins (21) are arranged on the outer side of the housing (8).
EP96922042A 1995-07-18 1996-06-28 Sensor for gas concentration measurement Withdrawn EP0781410A1 (en)

Applications Claiming Priority (5)

Application Number Priority Date Filing Date Title
DE19525942 1995-07-18
DE19525942 1995-07-18
DE19534918A DE19534918C2 (en) 1995-07-18 1995-09-20 Sensor for measuring gas concentrations
DE19534918 1995-09-20
PCT/EP1996/002835 WO1997004306A1 (en) 1995-07-18 1996-06-28 Sensor for gas concentration measurement

Publications (1)

Publication Number Publication Date
EP0781410A1 true EP0781410A1 (en) 1997-07-02

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EP (1) EP0781410A1 (en)
JP (1) JPH10506473A (en)
CN (1) CN1158164A (en)
AU (1) AU708240B2 (en)
BR (1) BR9606523A (en)
CA (1) CA2200203A1 (en)
TR (1) TR199700198T1 (en)
WO (1) WO1997004306A1 (en)

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JP4192823B2 (en) * 2003-06-06 2008-12-10 株式会社デンソー Gas sensor
NZ567538A (en) * 2005-10-19 2011-02-25 Jtl Australia Pty Ltd A slip type pipe joint
DE102011082260A1 (en) * 2011-09-07 2013-05-08 Robert Bosch Gmbh Sensor for determining at least one property of a sample gas in a sample gas chamber
EA032158B1 (en) * 2014-12-15 2019-04-30 Открытое Акционерное Общество "Акмэ-Инжиниринг" Sensor for sensing hydrogen in liquid and gaseous media

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US4230930A (en) * 1979-01-25 1980-10-28 Ford Motor Company Laser welding method for electrical wire connection to a terminal pin of an exhaust gas sensor
FR2492981A1 (en) * 1980-07-22 1982-04-30 Socapex GAS ANALYSIS PROBE
DE4312506A1 (en) * 1993-04-16 1994-10-20 Bosch Gmbh Robert Electrochemical oxygen sensor
DE4318789A1 (en) * 1993-06-05 1994-12-08 Bosch Gmbh Robert Seal for a sensor element of a gas sensor
GB2294330B (en) * 1993-07-27 1997-08-06 Bosch Gmbh Robert Electrochemical measuring probe with a sensor element arranged in a floating manner, and process for its manufacture
DE4342731B4 (en) * 1993-07-27 2004-09-09 Robert Bosch Gmbh Electrochemical sensor with a potential-free sensor element and method for its production

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AU6305996A (en) 1997-02-18
AU708240B2 (en) 1999-07-29
TR199700198T1 (en) 1997-08-21
JPH10506473A (en) 1998-06-23
CN1158164A (en) 1997-08-27
WO1997004306A1 (en) 1997-02-06
MX9702015A (en) 1997-11-29
CA2200203A1 (en) 1997-02-06

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