JP2805811B2 - Combustion control sensor - Google Patents
Combustion control sensorInfo
- Publication number
- JP2805811B2 JP2805811B2 JP1091337A JP9133789A JP2805811B2 JP 2805811 B2 JP2805811 B2 JP 2805811B2 JP 1091337 A JP1091337 A JP 1091337A JP 9133789 A JP9133789 A JP 9133789A JP 2805811 B2 JP2805811 B2 JP 2805811B2
- Authority
- JP
- Japan
- Prior art keywords
- oxygen
- combustion control
- solid electrolyte
- gas diffusion
- sensor
- 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.)
- Expired - Fee Related
Links
Landscapes
- Measuring Oxygen Concentration In Cells (AREA)
- Investigating Or Analyzing Materials By The Use Of Fluid Adsorption Or Reactions (AREA)
Description
【発明の詳細な説明】 産業上の利用分野 本発明は、燃焼排ガス中の残存酸素濃度により空気と
燃料の比を検出し、適正な燃焼状態を維持するために用
いる燃焼制御用センサに関するものである。Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a combustion control sensor for detecting the ratio of air to fuel based on the concentration of residual oxygen in combustion exhaust gas and maintaining an appropriate combustion state. is there.
従来の技術 従来、この種のセンサとしては、酸素イオン導電性固
体電解質基体として安定化ジルコニアを用い、陽極及び
陰極として白金を用い、さらに陰極上にガス拡散律速体
を設けた形のものがある。該センサにおいては、両極間
に印加される電圧により酸素ポンピング作用が生じて酸
素イオン導電性固体電解質基体中を酸素イオンが移動
し、これを電流として取り出すことができる。この酸素
イオンの移動は陰極上に設けたガス拡散律速体によって
結果として律速されるため、出力電流は一定値まで増加
した後飽和する。この飽和電流値は雰囲気中の酸素濃度
に応じた値を示すため、電流値を測定することにより、
排ガス中の酸素濃度を知ることができ、従って適正な空
燃比になるように燃焼を制御することが可能になる。2. Description of the Related Art Conventionally, as this type of sensor, there is a sensor in which stabilized zirconia is used as an oxygen ion-conductive solid electrolyte substrate, platinum is used as an anode and a cathode, and a gas diffusion-controlling member is provided on the cathode. . In this sensor, a voltage applied between the two electrodes causes an oxygen pumping action, whereby oxygen ions move in the oxygen ion conductive solid electrolyte substrate and can be extracted as a current. This movement of oxygen ions is rate-determined as a result by the gas diffusion rate-controlling member provided on the cathode, so that the output current is saturated after increasing to a certain value. Since this saturation current value indicates a value corresponding to the oxygen concentration in the atmosphere, by measuring the current value,
It is possible to know the oxygen concentration in the exhaust gas, so that it is possible to control the combustion so as to obtain an appropriate air-fuel ratio.
発明が解決しようとする課題 従来、ガス拡散律速体の材料としては、アルミナ、ス
ピネルなどが用いられており、酸素イオン導電性固体電
解質基体と無機接着剤などで接合されていた。Problems to be Solved by the Invention Conventionally, alumina, spinel, and the like have been used as the material of the gas diffusion control body, and they have been bonded to an oxygen ion conductive solid electrolyte substrate with an inorganic adhesive or the like.
しかし、この種のセンサにおいては、ガス拡散律速体
の材料と酸素イオン導電性固体電解質の熱膨張係数が異
なり、かつ耐熱衝撃特性も異なるため、往々にして酸素
イオン導電性固体電解質基体の破損が生じることがあっ
た。However, in this type of sensor, the material of the gas diffusion-controlling body and the oxygen ion conductive solid electrolyte have different coefficients of thermal expansion and different thermal shock resistance, so that the oxygen ion conductive solid electrolyte substrate often breaks. May have occurred.
これに対処するため、酸素ポンプを構成する固体電解
質基体と同じ材料をガス拡散律速体として用いることが
行なわれる。この種のセンサにおいては、応答性を高め
るために、デッドスペースを極力小さくする必要があ
り、ガス拡散律速体を陰極に密着させることがしばしば
行なわれる。In order to cope with this, the same material as the solid electrolyte substrate constituting the oxygen pump is used as a gas diffusion control body. In this type of sensor, it is necessary to minimize the dead space in order to improve responsiveness, and it is often the case that the gas diffusion control body is brought into close contact with the cathode.
しかし固体電解質材料をガス拡散律速体として陰極に
密着させると、ガス拡散律速体自体が導電性を有するた
めに、導電パスを形成してセンサの電気特性に異常な特
性が現われることがある。However, if the solid electrolyte material is brought into close contact with the cathode as a gas diffusion-controlling body, the gas diffusion-controlling body itself has conductivity, so that a conductive path may be formed and abnormal electrical characteristics may appear in the sensor.
課題を解決するための手段 本発明は、酸素イオン導電性固体電解質からなる基体
上に設ける一対の電極の内、陰極となる電極を形成した
面を覆って、酸素イオン導電性固体電解質および電極材
料と非反応性でありかつガス透過性の電気絶縁性の多孔
質層を形成し、該多孔質層上に前記酸素イオン導電性固
体電解質と同じ材料からなるガス拡散律速体を密着させ
てなることを特徴とする燃焼制御用センサである。Means for Solving the Problems The present invention covers an oxygen ion conductive solid electrolyte and an electrode material by covering a surface on which an electrode serving as a cathode is formed, among a pair of electrodes provided on a substrate made of an oxygen ion conductive solid electrolyte. Forming an electrically insulating porous layer that is non-reactive and gas permeable, and that a gas diffusion rate controlling body made of the same material as the oxygen ion conductive solid electrolyte is adhered onto the porous layer. A combustion control sensor characterized by the following.
作用 本発明による燃焼制御用センサにおいては、ガス拡散
律速体と酸素ポンプ基体用固体電解質が同じ材料からな
るため、熱膨張の不一致や機械的強度の違いによるセン
サの破損が生じない。また、陰極とガス拡散律速体とは
互いに絶縁されているため、電気特性の変動や異常もな
く安定したセンサ特性が得られる。Effect In the combustion control sensor according to the present invention, since the gas diffusion control body and the solid electrolyte for the oxygen pump base are made of the same material, the sensor does not break due to a mismatch in thermal expansion or a difference in mechanical strength. In addition, since the cathode and the gas diffusion control body are insulated from each other, stable sensor characteristics can be obtained without fluctuations or abnormalities in electrical characteristics.
実 施 例 第１図は本発明の一実施例における燃料制御用センサ
素子を示す模式的断面図である。１は8mol％Y2O3安定化
ジルコニア固体電解質基体（5.5mmφ×0.5mmt）、２は
化学式La0.35Sr0.65Co0.7Fe0.3O3-δで表わされるペロ
ブスカイト型複合酸化物をスパッタによって付着させて
形成した陰極（0.1μmt）、３は同じく化学式La0.35Sr
0.65Co0.7Fe0.3O3-δで表わされるペロブスカイト型複
合酸化物をスパッタによって付着させて形成した陽極
（0.1μmt）、４はSrTiO3をスパッタにより付着させて
形成した絶縁性の多孔質層（0.05μmt）、５は8mol％Y2
O3安定化ジルコニアからなるガス拡散律速体、６はガス
拡散用細孔、７は電極リードである。なお、電極リード
７とガス拡散律速体５は図示しない方法により絶縁され
ている。FIG. 1 is a schematic cross-sectional view showing a fuel control sensor element according to an embodiment of the present invention. 1 is an 8 mol% Y 2 O 3 stabilized zirconia solid electrolyte substrate (5.5 mmφ × 0.5 mmt), and 2 is a perovskite-type composite oxide represented by a chemical formula of La 0.35 Sr 0.65 Co 0.7 Fe 0.3 O 3- δ attached by sputtering. Cathode (0.1μmt), 3 has the same formula La 0.35 Sr
An anode (0.1 μmt) formed by depositing a perovskite-type composite oxide represented by 0.65 Co 0.7 Fe 0.3 O 3- δ by sputtering, and 4 is an insulating porous layer formed by depositing SrTiO 3 by sputtering ( 0.05μmt), 5 is 8mol% Y 2
A gas diffusion control body made of O 3 stabilized zirconia, 6 is a gas diffusion pore, and 7 is an electrode lead. The electrode lead 7 and the gas diffusion control body 5 are insulated by a method not shown.
比較のため、絶縁層を形成せず、8mol％Y2O3安定化ジ
ルコニアのガス拡散律速体を用いたセンサ素子（従来例
１）、及び絶縁層を形成せずMgAl2O3からなるガス拡散
律速体を用いたセンサ素子（従来例２）をそれぞれ作製
した。For comparison, a sensor element (conventional example 1) using an 8 mol% Y 2 O 3 stabilized zirconia gas diffusion controlling body without forming an insulating layer, and a gas made of MgAl 2 O 3 without forming an insulating layer Sensor elements (conventional example 2) using a diffusion-controlling body were manufactured.
先ず、これらのセンサの初期特性を測定し評価した。
測定は以下のようにして行なった、電気炉中にセンサ素
子を設置し、素子温度が700℃になるように温度制御を
行ない、所定濃度の酸素−窒素混合ガスを約10cm/secの
流速で流通接触させた。このとき、印加する電圧に対す
る出力電流を測定し、一定電圧（1v）印加時における出
力電流を各酸素濃度に対して求め、これを初期特性とし
た。その結果を第２図に示した。この結果、本発明にな
るセンサ素子及び従来例２のセンサ素子は共に酸素濃度
と電流の間に比例関係が認められたが、従来例１のセン
サ素子においてはこのような比例関係が認められなかっ
た。従来例１では、陰極と8mol％Y2O3安定化ジルコニア
からなるガス拡散律速体が直接接触しているため、ガス
拡散律速体中に導電パスが形成されて電圧−電流特性に
特異な特性が生じたものと考えられる。First, the initial characteristics of these sensors were measured and evaluated.
The measurement was performed as follows.A sensor element was installed in an electric furnace, temperature control was performed so that the element temperature became 700 ° C., and an oxygen-nitrogen mixed gas having a predetermined concentration was supplied at a flow rate of about 10 cm / sec. The contact was in circulation. At this time, the output current with respect to the applied voltage was measured, and the output current when a constant voltage (1 v) was applied was obtained for each oxygen concentration, and this was used as the initial characteristic. The results are shown in FIG. As a result, both of the sensor element according to the present invention and the sensor element of the conventional example 2 showed a proportional relationship between the oxygen concentration and the current, but the sensor element of the conventional example 1 did not show such a proportional relationship. Was. In Conventional Example 1, the cathode is in direct contact with the gas diffusion-controlling body made of 8 mol% Y 2 O 3 stabilized zirconia, so that a conductive path is formed in the gas diffusion-controlling body, resulting in a characteristic peculiar to the voltage-current characteristic. Is considered to have occurred.
次に、各20個のセンサ素子について温度サイクル試験
を行ない、センサ素子の破損の有無等を評価した。試験
は、300℃ 900℃の温度サイクル（200℃/hの昇降温）
を50回繰り返し、目視にて素子の状態を確認した。その
結果を次表に示した。Next, a temperature cycle test was performed on each of the 20 sensor elements to evaluate whether the sensor elements were damaged or not. The test is performed at a temperature cycle of 300 ° C 900 ° C (200 ° C / h temperature rise / fall)
Was repeated 50 times, and the state of the element was visually confirmed. The results are shown in the following table.
従来例２においては、いずれも安定化ジルコニア基体
が破損していた。これに対して実施例及び従来例１では
ガス拡散律速体も安定化ジルコニアからなっているた
め、温度サイクルによっても異常な歪が生じることがな
く、従ってセンサの破損も生じない。また、実施例のセ
ンサの温度サイクル試験後の特性は、初期特性からほと
んど変化していないことも明らかになった。しかし、従
来例１のセンサの特性は先に述べた例と同様に異常な電
圧−電流特性を示した。 In Conventional Example 2, the stabilized zirconia substrate was damaged in each case. On the other hand, in Example 1 and Conventional Example 1, since the gas diffusion control body is also made of stabilized zirconia, no abnormal distortion is caused even by a temperature cycle, and therefore, the sensor is not damaged. Further, it was also found that the characteristics of the sensors of the examples after the temperature cycle test hardly changed from the initial characteristics. However, the characteristics of the sensor of the conventional example 1 showed abnormal voltage-current characteristics similarly to the above-described example.
以上の実施例で明らかなように、本発明になる燃焼制
御用センサは極めて優れた特性を示す。As is clear from the above embodiments, the combustion control sensor according to the present invention exhibits extremely excellent characteristics.
なお、酸素イオン導電性固体電解質、及びガス拡散律
速体としては8mol％Y2O3安定化ジルコニアを用いたが、
同様の機能を有するものであればこれに限定するもので
はない。電極材料も実施例に限定するものではなく、望
ましくは請求項（２）（３）（４）で記載されるものの
中から選択されることが好ましく、同様の機能を有する
ものであればよい。特にSrMe′O3あるいは白金族元素を
添加した場合は、応答特性あるいは低温特性の向上が認
められ、好適である。センサ形態も発明の主旨に反しな
い限り任意の形態を取り得るものである。ガス拡散律速
体としては、実施例のように細孔を設けたものに限ら
ず、多孔質材料を用いることもできる。また、焼結体の
貼合わせに限らず多孔質のコーティング層を形成するこ
ともできる。また、絶縁層自体をガス拡散律速体あるい
はその一部とすることも可能である。絶縁層材料も電
極、リードなどと非反応性のものであれば実施例に限定
するものではない。センサの作製法も焼結、印刷、溶射
その他の方法、及びそれらの組合せを用いることができ
るものである。Note that 8 mol% Y 2 O 3 stabilized zirconia was used as the oxygen ion conductive solid electrolyte and the gas diffusion controlling body,
It is not limited to this as long as it has a similar function. The electrode material is not limited to the embodiment, but is preferably selected from those described in claims (2), (3) and (4), and may be any material having the same function. Particularly case of adding SrMe'O 3 or a platinum group element, improvement of the response characteristic or the low temperature characteristic is observed, which is preferable. The sensor may take any form as long as it does not contradict the gist of the invention. The gas diffusion controlling body is not limited to the one having pores as in the embodiment, but a porous material can also be used. Further, a porous coating layer can be formed without being limited to the bonding of the sintered bodies. Further, the insulating layer itself can be a gas diffusion controlling body or a part thereof. The material of the insulating layer is not limited to the examples as long as it is non-reactive with the electrodes and leads. The manufacturing method of the sensor can also use sintering, printing, thermal spraying and other methods, and a combination thereof.
発明の効果 以上のように、本発明になる燃焼制御用センサはきわ
めて安定した特性を示し、長期間にわたって精度よく燃
焼排ガス中の酸素濃度を測定でき、適正な燃焼状態に制
御することができ、且つ熱膨張の不一致や機械的強度の
違いによる破損という問題点を解決したものである。Effect of the Invention As described above, the combustion control sensor according to the present invention exhibits extremely stable characteristics, can accurately measure the oxygen concentration in the combustion exhaust gas over a long period of time, and can control the combustion state appropriately. Further, the problem of breakage due to mismatch of thermal expansion and difference in mechanical strength is solved.
第１図は本発明の一実施例における燃焼制御用センサの
模式的断面図、第２図は同実施例および従来例のセンサ
の出力特性図である。 １……酸素イオン導電性固体電解質基体、２……陰極、
３……陽極、４……絶縁層、５……ガス拡散律速体、６
……ガス拡散用細孔、７……電極リード。FIG. 1 is a schematic sectional view of a combustion control sensor according to an embodiment of the present invention, and FIG. 2 is an output characteristic diagram of the sensor of the embodiment and a conventional example. 1 ... oxygen ion conductive solid electrolyte substrate, 2 ... cathode,
3 ... Anode, 4 ... Insulating layer, 5 ... Gas diffusion controlling body, 6
... gas diffusion pores, 7 ... electrode leads.
───────────────────────────────────────────────────── フロントページの続き (56)参考文献 特開 昭59−192953（ＪＰ，Ａ) 特開 昭63−158451（ＪＰ，Ａ) 実開 昭60−170770（ＪＰ，Ｕ) (58)調査した分野(Int.Cl.6，ＤＢ名) G01N 27/41──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-59-192953 (JP, A) JP-A-63-158451 (JP, A) Real opening Sho-60-170770 (JP, U) (58) Field (Int.Cl. 6 , DB name) G01N 27/41
Claims (4)
上に設ける一対の電極の内、陰極となる電極を形成した
面を覆って、酸素イオン導電性固体電解質および電極材
料と非反応性でありかつガス透過性の電気絶縁性の多孔
質層を形成し、該多孔質層上に前記酸素イオン導電性固
体電解質と同じ材料からなるガス拡散律速体を密着させ
てなることを特徴とする燃焼制御用センサ。1. A pair of electrodes provided on a substrate made of an oxygen-ion-conductive solid electrolyte and covering a surface on which an electrode serving as a cathode is formed, and non-reactive with the oxygen-ion-conductive solid electrolyte and the electrode material. And combustion control characterized by forming a gas-permeable electrically insulating porous layer, and adhering a gas diffusion-controlling body made of the same material as the oxygen ion conductive solid electrolyte on the porous layer. For sensors.
一般式Ln1-xAxCo1-yMeyO3-δ（LnはLa,Ce,Pr,Ndから選
ぶ少なくとも一種の元素、MeはNi,Fe,Mn,Cr,Vから選ぶ
少なくとも一種の元素、０≦ｘ≦１、０≦ｙ≦１、δは
酸素欠損量）で表されるペロブスカイト型複合酸化物か
らなることを特徴とする請求項１記載の燃焼制御用セン
サ。2. The method according to claim 1, wherein at least one electrode of the pair of electrodes has a general formula Ln 1-x A x Co 1-y Me y O 3- δ (Ln is at least one element selected from La, Ce, Pr, Nd, Me is at least one element selected from Ni, Fe, Mn, Cr, and V, and is characterized by being composed of a perovskite-type composite oxide represented by 0 ≦ x ≦ 1, 0 ≦ y ≦ 1, and δ is an oxygen deficiency). The combustion control sensor according to claim 1, wherein:
選ぶ少なくとも一種の元素）を添加することを特徴とす
る請求項１または２記載の燃焼制御用センサ。3. The combustion control sensor according to claim 1, wherein SrMe′O 3 (Me is at least one element selected from Ti, Zr, Hf) is added to the electrode material.
添加することを特徴とする請求項１〜３のいずれかに記
載の燃焼制御用センサ。4. The combustion control sensor according to claim 1, wherein at least one platinum group element is added to the electrode material.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1091337A JP2805811B2 (en) | 1989-04-11 | 1989-04-11 | Combustion control sensor |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1091337A JP2805811B2 (en) | 1989-04-11 | 1989-04-11 | Combustion control sensor |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH02269948A JPH02269948A (en) | 1990-11-05 |
| JP2805811B2 true JP2805811B2 (en) | 1998-09-30 |
Family
ID=14023616
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP1091337A Expired - Fee Related JP2805811B2 (en) | 1989-04-11 | 1989-04-11 | Combustion control sensor |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2805811B2 (en) |
Families Citing this family (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5269822A (en) * | 1992-09-01 | 1993-12-14 | Air Products And Chemicals, Inc. | Process for recovering oxygen from gaseous mixtures containing water or carbon dioxide which process employs barium-containing ion transport membranes |
| US5240473A (en) * | 1992-09-01 | 1993-08-31 | Air Products And Chemicals, Inc. | Process for restoring permeance of an oxygen-permeable ion transport membrane utilized to recover oxygen from an oxygen-containing gaseous mixture |
| US5261932A (en) * | 1992-09-01 | 1993-11-16 | Air Products And Chemicals, Inc. | Process for recovering oxygen from gaseous mixtures containing water or carbon dioxide which process employs ion transport membranes |
| US5695624A (en) * | 1995-01-30 | 1997-12-09 | The Regents Of The Univeristy Of California | Solid state oxygen sensor |
| DE19744316C2 (en) * | 1997-10-08 | 2000-09-21 | Univ Karlsruhe | Oxygen sensitive resistance material |
Family Cites Families (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS59192953A (en) * | 1983-12-12 | 1984-11-01 | Toyota Central Res & Dev Lab Inc | Analytical apparatus for concentration of gaseous oxygen |
| JPS60170770U (en) * | 1984-04-20 | 1985-11-12 | トヨタ自動車株式会社 | oxygen concentration detector |
| JPS63158451A (en) * | 1986-12-23 | 1988-07-01 | Tech Res Assoc Conduct Inorg Compo | Combustion control sensor |
-
1989
- 1989-04-11 JP JP1091337A patent/JP2805811B2/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| JPH02269948A (en) | 1990-11-05 |
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|---|---|---|---|
| LAPS | Cancellation because of no payment of annual fees |