EP1285262A1 - Dispositif de mesure pour determiner la concentration de composants gazeux contenus dans des gaz d'echappement d'un moteur a combustion interne, et procede pour commander le fonctionnement du dispositif de mesure - Google Patents

Dispositif de mesure pour determiner la concentration de composants gazeux contenus dans des gaz d'echappement d'un moteur a combustion interne, et procede pour commander le fonctionnement du dispositif de mesure

Info

Publication number
EP1285262A1
EP1285262A1 EP01945084A EP01945084A EP1285262A1 EP 1285262 A1 EP1285262 A1 EP 1285262A1 EP 01945084 A EP01945084 A EP 01945084A EP 01945084 A EP01945084 A EP 01945084A EP 1285262 A1 EP1285262 A1 EP 1285262A1
Authority
EP
European Patent Office
Prior art keywords
chamber
oxygen
gas
pump
hydrogen
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Withdrawn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
EP01945084A
Other languages
German (de)
English (en)
Inventor
Harald Loeck
Uwe Kammann
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.)
Volkswagen AG
Original Assignee
Volkswagen AG
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
Application filed by Volkswagen AG filed Critical Volkswagen AG
Publication of EP1285262A1 publication Critical patent/EP1285262A1/fr
Withdrawn legal-status Critical Current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
    • G01N27/416—Systems
    • G01N27/417—Systems using cells, i.e. more than one cell and probes with solid electrolytes

Definitions

  • Measuring device for determining the concentration of gas components in the exhaust gas of an internal combustion engine and method for controlling a
  • the invention relates to a measuring device for determining the concentration of gas components in the exhaust gas of an internal combustion engine with the features mentioned in claim 1 and a method for controlling an operation of the measuring device with the features mentioned in claim 8.
  • a double-chamber HC sensor is known from EP 731 351 A3, which makes it possible to determine the concentration of HC even in the presence of H 2 and CO.
  • the sensor has a first chamber to which an oxygen pump is assigned and which can come into contact with an engine exhaust gas via a first diffusion channel. The measurement gas can then enter a second chamber via a diffusion channel adjoining the first chamber.
  • An oxygen pump and an additional hydrogen pump are also housed here.
  • the pump systems each consist of a pair of electrodes, the inner electrodes of which face the chambers and the outer electrodes of which are separated from the measurement gas by a solid electrolyte.
  • oxygen pumps that is Solid electrolyte conducts oxygen ions and, in the case of the hydrogen pump, proton conducts.
  • the oxygen is extracted from the sample gas in the first chamber.
  • hydrogen and a hydrogen portion of any gaseous water that may be present are removed from the measuring gas via the hydrogen pump.
  • the oxygen pump in the second chamber provides oxygen for the oxidation of HC and an HC concentration is determined in accordance with the pump current detected for this process.
  • a disadvantage of the solution shown is the high concentration of hydrogen and gaseous water, at least at the beginning of the measurement, which leads to a disruption of the oxidative decomposition of HC. This ultimately results in an imprecise determination of the concentration of HC.
  • Another disadvantage of the sensor shown is that it is only used to determine the HC concentration.
  • the object of the present invention is to provide a measuring device with which the concentration of various gas components in the exhaust gas of internal combustion engines can be determined with high accuracy.
  • the measurement should take place with only a single sensor element which is arranged in the exhaust line.
  • this object is achieved by the measuring device for determining the concentration of gas components in the exhaust gas of the internal combustion engine with the features mentioned in claim 1 and with the method for controlling the operation of the measuring device according to the features mentioned in claim 8.
  • the measuring device consists of at least
  • At least one electrochemical oxygen pump in the region of the two chambers which consists of an inner electrode exposed to the measuring gas in the chamber and a second electrode which can be conductively contacted with the inner electrode via an oxygen ion-conducting layer, the second electrode being in a reference chamber is exposed to the oxygen-containing reference gas,
  • an evaluation unit that detects a current flow of the hydrogen pumps and / or the oxygen pump of the second chamber as a function of the measurement mode and determines the concentration of at least one gas component from this.
  • a measurement mode of the claimed measuring device is specified as a function of the gas component or components to be determined, the voltages to be specified by the control unit and the evaluation parameters to be observed in the evaluation unit being determined via the measurement mode. It is possible to determine a concentration of NO x in a first measurement mode and a concentration of hydrogen and / or HC in a second measurement mode.
  • the proton-conducting layer of the measuring device is preferably a solid electrolyte, in particular based on perovskites containing barium.
  • a solid electrolyte is also preferably used as the oxygen ion-conducting layer.
  • the diffusion channels of the measuring device preferably consist of a porous ceramic, the porosity of which can be adapted to the desired application. It has also proven advantageous to form the inner electrode of the oxygen pump of the first chamber from a cermet consisting of platinum and zirconium dioxide. With such an electrode, reducing agents such as carbon monoxide, HC and Hydrogen are oxidized in a lean atmosphere. It is also preferred that an additional oxygen pump (auxiliary pump) is arranged in the area of the second chamber, which removes excess oxygen from the second measuring chamber.
  • auxiliary pump is arranged in the area of the second chamber, which removes excess oxygen from the second measuring chamber.
  • the first measurement mode the first measurement mode
  • the oxygen pump formed on the inner electrode of the oxygen pump in the second chamber by reducing NO x is withdrawn from the sample gas via the oxygen pump and
  • the remaining oxygen is removed via the auxiliary pump of the second chamber during the determination of the NO x concentration.
  • the NO x concentration can be determined with very high measurement accuracy in the manner shown.
  • the second measurement mode is preferably carried out for determining the concentration of hydrogen in such a way that
  • the oxygen pump maintains an at least slightly rich oxygen ratio in the measurement gas of the first chamber
  • the hydrogen concentration is determined in the evaluation unit on the basis of the pump currents of the hydrogen pumps of the first and the second chamber and a correction factor for the water content.
  • the correction factor for compensating the water content is preferably in the range from 12 to 16%, in particular 14%.
  • an HC concentration is determined in the evaluation unit on the basis of the pump currents of the oxygen pump of the second chamber.
  • the concentration of hydrogen or HC can therefore be determined in the second measurement mode, while the first measurement mode allows the NO x concentration to be determined with high accuracy.
  • Figure 1 is a schematic sectional view through a sensor element as part of a
  • Measuring device for determining the concentration of gas components
  • Figure 2 is a schematic representation of the procedure in the area of
  • Figure 3 is a schematic representation of the procedure in the area of
  • Chamber of the sensor element during a measurement in a second measurement mode Chamber of the sensor element during a measurement in a second measurement mode.
  • FIG. 1 shows a schematic sectional view of a sensor element 10, as can be used for the measuring device according to the invention.
  • the sensor element 10 is arranged at a suitable position in an exhaust line of an internal combustion engine and is used to determine a concentration of nitrogen oxides NO x , hydrogen and incompletely burned hydrocarbons HC.
  • the internal combustion engine can be a diesel engine and a gasoline engine, in particular a direct injection gasoline engine.
  • the exhaust gas of the internal combustion engine can enter a first chamber 12 via a diffusion channel 14 and subsequently diffuse into a second chamber 18 via a subsequent second diffusion channel 16.
  • a reference gas chamber 20 extends below the two chambers 12, 18 and is usually filled with a gas of known oxygen concentration.
  • An upper side of the measuring chambers 12, 18 is usually also formed on the basis of a solid electrolyte by a proton-conducting layer 24.
  • the oxygen pump 26 includes an inner electrode 30 that is exposed to the measurement gas in the first chamber 12 and an outer electrode 32 that is exposed to the reference gas.
  • the inner electrode 30 is formed from a platinum cermet to support oxidation of reducing agents to be explained in more detail in a slightly lean atmosphere.
  • the electrodes 34, 36 are arranged in an analogous manner in the second chamber 18 or the reference gas chamber 20.
  • the inner electrode 36 is also based on a noble metal cermet realizable.
  • platinum-based alloys are suitable as noble metals, since these catalyze the decomposition of nitrogen oxides NO x, which is explained in more detail, or the oxidation of HC.
  • the chambers 12, 18 are each assigned a hydrogen pump 38, 40, which in turn consist of inner electrodes 42, 46 and outer electrodes 44, 48.
  • a catalytically active component is added to the inner electrodes 42, 46 to support the decomposition of gaseous water which may be present in the measurement gas.
  • the sensor element 10 is part of a measuring device which is not shown completely here for reasons of clarity.
  • the measuring device additionally comprises a control unit with which a voltage to the oxygen pumps 26, 28 and the hydrogen pumps 38, 40 can be predetermined as a function of a predeterminable measuring mode.
  • a control unit with which a voltage to the oxygen pumps 26, 28 and the hydrogen pumps 38, 40 can be predetermined as a function of a predeterminable measuring mode.
  • an evaluation unit with which, depending on the measurement mode, a current flow at the hydrogen pumps 38, 40 and / or the oxygen pump 28 of the second measurement chamber is detected and from which the concentration of at least one gas component can be determined.
  • a first measuring mode in which the NO x concentration is determined by the measuring device, can be seen in FIG. 2 in its sequence.
  • the two chambers 12, 18 and the partial processes taking place in this area are shown schematically here. Arrows pointing upward indicate a pumping process in the direction of exhaust gas and arrows pointing downward indicate a pumping process against air.
  • the exhaust gas diffuses through the diffusion channel 14 into the first chamber 12.
  • the pump 26 is given a voltage via the control unit, with which a constant, slightly lean oxygen ratio in the measurement gas of the first chamber 12 can be maintained.
  • the hydrogen is withdrawn from the measurement gas of the first chamber 12 via the hydrogen pump 38 - by oxidation of hydrogen to water.
  • the NO x on the inner electrode 36 of the oxygen pump 28 is reduced and the oxygen which is produced is removed from the measurement gas by the oxygen pump 28.
  • a further oxygen pump (auxiliary pump), not shown here, can be used to remove the residual oxygen fraction from the first chamber 12 into the second chamber 18 after the measurement gas has diffused.
  • auxiliary pump can be used to remove the residual oxygen fraction from the first chamber 12 into the second chamber 18 after the measurement gas has diffused.
  • the pumping current of the oxygen pump 28 is detected by the evaluation unit and the NO x concentration is determined as a function thereof.
  • the hydrogen pump 40 is deactivated during the NO x concentration determination, that is to say in the first measurement mode.
  • FIG. 3 A schematic representation of the processes that take place during a second measurement mode for determining hydrogen and / or HC can be seen in FIG. 3.
  • An at least slightly rich oxygen ratio in the measurement gas of the first chamber 12 is maintained via the acid pump 26 during the second measurement mode.
  • oxygen and an oxygen portion of any gaseous water that may be present are therefore pumped out of the first chamber 12.
  • decomposition of HC and hydrogen on the inner electrode 30 of the oxygen pump 26 is avoided.
  • Existing nitrogen oxide components are extracted from the sample gas by reaction with carbon monoxide.
  • hydrogen and a hydrogen portion of the water are extracted from the measurement gas by specifying a suitable voltage by means of the hydrogen pump 38.
  • oxygen pump 28 After diffusion into the second measuring chamber 18, oxygen is now pumped into the chamber 18 via the oxygen pump 28, to the extent that oxygen is used to oxidize HC. At the same time, a residual hydrogen portion of the measurement gas is pumped out via the hydrogen pump 40.
  • the pump current of the oxygen pump 28 is a measure of the HC concentration and is therefore used to determine the same in the evaluation unit.
  • the cumulative pump currents of the hydrogen pumps 38, 40 still have to be corrected in the evaluation unit to compensate for the water content. If the water content cannot be determined directly, a fixed correction factor can be used, which is in the range of 12 to 16%, in particular 14%.
  • Sensor element chamber first diffusion channel, first diffusion channel, second chamber, second reference gas chamber oxygen ion-conducting layer proton-conducting layer oxygen pump of the first chamber oxygen pump of the second chamber inner electrode of the first chamber outer electrode of the first chamber inner electrode of the second chamber outer electrode of the second chamber hydrogen pump of the first Chamber hydrogen pump of the second chamber inner electrode of the first chamber outer electrode of the first chamber inner electrode of the second chamber outer electrode of the second chamber

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

Abstract

L'invention concerne un dispositif de mesure et un procédé pour déterminer la concentration de composants gazeux contenus dans les gaz d'échappement d'un moteur à combustion interne, qui est constitué d'au moins: (a) une première chambre (12), reliée au système d'évacuation des gaz d'échappement par l'intermédiaire d'un premier canal de diffusion (14), et une seconde chambre (18), reliée à la première chambre (12) par l'intermédiaire d'un second canal de diffusion (16); (b) au moins une pompe à hydrogène (38, 40) électrochimique, se trouvant dans la zone de chacune des deux chambres (12, 18), qui est constituée d'une électrode intérieure (42, 46), exposée aux gaz à mesurer se trouvant dans la chambre, et d'une électrode extérieure (44, 48), qui peut être mise en contact, de façon conductrice, avec l'électrode intérieure (42, 46), par l'intermédiaire d'une couche (24) conductrice de protons; (c) au moins une pompe à oxygène (26, 28) électrochimique se trouvant dans chacune des deux chambres (12, 18), qui constituée d'une électrode intérieure (30, 36), qui est exposée aux gaz à mesurer se trouvant dans la chambre, et d'une seconde électrode (32, 34), qui peut être mise en contact de façon conductrice avec l'électrode intérieure (30, 36), par l'intermédiaire d'une couche (22) conduisant les ions oxygène, cette seconde électrode (32, 34) étant exposée à un gaz de référence contenant de l'oxygène, se trouvant dans une chambre à gaz de référence (20); (d) une unité de commande avec laquelle, en fonction d'un mode de mesure préallouable, une tension peut être préallouée aux pompes à oxygène (26, 28) et aux pompes à hydrogène (38, 40); et (e) une unité d'exploitation, qui, en fonction du mode de mesure détecte un flux de courant des pompes à hydrogène (38, 40) et/ou des pompes à oxygènes (28) de la seconde chambre (18) et détermine, à partir de ce flux de courant, la concentration d'au moins un composant gazeux.
EP01945084A 2000-05-11 2001-05-04 Dispositif de mesure pour determiner la concentration de composants gazeux contenus dans des gaz d'echappement d'un moteur a combustion interne, et procede pour commander le fonctionnement du dispositif de mesure Withdrawn EP1285262A1 (fr)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
DE10023062 2000-05-11
DE10023062.8A DE10023062B4 (de) 2000-05-11 2000-05-11 Messeinrichtung zur Konzentrationsbestimmung von Gaskomponenten im Abgas einer Brennkraftmaschine und Verfahren zur Steuerung eines Betriebs der Messeinrichtung
PCT/EP2001/005056 WO2001086277A1 (fr) 2000-05-11 2001-05-04 Dispositif de mesure pour determiner la concentration de composants gazeux contenus dans des gaz d'echappement d'un moteur a combustion interne, et procede pour commander le fonctionnement du dispositif de mesure

Publications (1)

Publication Number Publication Date
EP1285262A1 true EP1285262A1 (fr) 2003-02-26

Family

ID=7641638

Family Applications (1)

Application Number Title Priority Date Filing Date
EP01945084A Withdrawn EP1285262A1 (fr) 2000-05-11 2001-05-04 Dispositif de mesure pour determiner la concentration de composants gazeux contenus dans des gaz d'echappement d'un moteur a combustion interne, et procede pour commander le fonctionnement du dispositif de mesure

Country Status (3)

Country Link
EP (1) EP1285262A1 (fr)
DE (1) DE10023062B4 (fr)
WO (1) WO2001086277A1 (fr)

Families Citing this family (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1452860B1 (fr) * 2003-02-27 2010-04-14 Robert Bosch Gmbh Procédé pour la détermination de l'ammoniac
US7763154B2 (en) 2003-09-03 2010-07-27 Robert Bosch Gmbh Method and sensor element for determining a gas in a gas mixture
RU2493560C1 (ru) * 2012-01-10 2013-09-20 Российская Федерация, от имени которой выступает Государственная корпорация по атомной энергии "Росатом" Система контроля кислорода и водорода в газовых средах
DE102013010561A1 (de) 2013-06-25 2015-01-08 Volkswagen Aktiengesellschaft Sensor zur Detektion von Kohlenwasserstoffen in einem Gasgemisch, seine Verwendung zur Bestimmung eines HC-Partialdrucks im Abgas eines Verbrennungsmotors sowie Kraftfahrzeug mit einem solchen

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JP2885336B2 (ja) * 1994-04-21 1999-04-19 日本碍子株式会社 被測定ガス中のＮＯｘ濃度の測定方法及び測定装置
US5575959A (en) * 1994-04-22 1996-11-19 Hughes Aircraft Company Process for making low cost infrared windows
JP3450084B2 (ja) * 1995-03-09 2003-09-22 日本碍子株式会社 可燃ガス成分の測定方法及び測定装置
JP3050781B2 (ja) * 1995-10-20 2000-06-12 日本碍子株式会社 被測定ガス中の所定ガス成分の測定方法及び測定装置
JP3623065B2 (ja) * 1996-02-23 2005-02-23 日本碍子株式会社 窒素酸化物センサ
DE19854889A1 (de) * 1997-11-27 1999-06-02 Denso Corp Gassensor mit Regelung der Sauerstoffkonzentration
KR100319947B1 (ko) * 1998-04-06 2002-01-09 마츠시타 덴끼 산교 가부시키가이샤 탄화수소 센서

Non-Patent Citations (1)

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Title
See references of WO0186277A1 *

Also Published As

Publication number Publication date
DE10023062A1 (de) 2001-11-15
WO2001086277A1 (fr) 2001-11-15
DE10023062B4 (de) 2015-10-15

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