JPH0631423Y2 - Air-fuel ratio sensor - Google Patents
Air-fuel ratio sensorInfo
- Publication number
- JPH0631423Y2 JPH0631423Y2 JP1987155660U JP15566087U JPH0631423Y2 JP H0631423 Y2 JPH0631423 Y2 JP H0631423Y2 JP 1987155660 U JP1987155660 U JP 1987155660U JP 15566087 U JP15566087 U JP 15566087U JP H0631423 Y2 JPH0631423 Y2 JP H0631423Y2
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- Prior art keywords
- electrode
- oxygen gas
- oxygen
- fuel ratio
- air
- Prior art date
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Description
【考案の詳細な説明】 ［産業上の利用分野］ 本考案は、酸素ポンプ素子と酸素ガス検出素子とを備え
る空燃比センサに関する。DETAILED DESCRIPTION OF THE INVENTION [Industrial application] The present invention relates to an air-fuel ratio sensor including an oxygen pump element and an oxygen gas detection element.
［従来の技術］ 従来より、例えば、内燃機関等の燃焼機器において、燃
費やエミッションの改善を図り最適な条件で運転するた
めに、空燃比センサにより排気中の酸素濃度を検出し、
燃焼機器中で燃焼される混合気を所望の空燃比に制御す
ることが行われている。[Prior Art] Conventionally, for example, in a combustion device such as an internal combustion engine, an air-fuel ratio sensor detects an oxygen concentration in exhaust gas in order to improve fuel efficiency and emission and operate under optimum conditions.
Controlling the air-fuel mixture burned in a combustion device to a desired air-fuel ratio is performed.
上記のような空燃比センサとして、ZrO2等の酸素イオン
伝導性固体電解質を用いた板状酸素ポンプ素子上に、Ti
O2等の周囲雰囲気の酸素ガス濃度に応じて抵抗の変化す
る金属酸化物からなる酸素ガス検出素子を積層し、さら
に酸素ガス検出素子上に周囲雰囲気を拡散制限的に連通
する多孔質層とを積層した構造の空燃比センサが、例え
ば特開昭６１−１９５３３８号に提案されている。As an air-fuel ratio sensor as described above, on a plate-shaped oxygen pump element using an oxygen ion conductive solid electrolyte such as ZrO 2 , Ti
An oxygen gas detection element made of a metal oxide whose resistance changes according to the oxygen gas concentration of the ambient atmosphere such as O 2 is laminated, and a porous layer that communicates with the ambient atmosphere on the oxygen gas detection element in a diffusion-limited manner. An air-fuel ratio sensor having a laminated structure is proposed in, for example, Japanese Patent Application Laid-Open No. 61-195338.
この空燃比センサは、酸素ポンプ素子と酸素ガス検出素
子との界面近傍の空燃比λが、例えばλ＝１となるよう
酸素ガス検出素子の出力によって酸素ポンプ素子に印加
されるポンプ電流Ｉｐを調整し、このポンプ電流Ｉｐか
ら周囲雰囲気の空燃比を求めるようにして使用される。This air-fuel ratio sensor adjusts the pump current Ip applied to the oxygen pump element by the output of the oxygen gas detection element so that the air-fuel ratio λ near the interface between the oxygen pump element and the oxygen gas detection element becomes, for example, λ = 1. Then, the air-fuel ratio of the ambient atmosphere is obtained from the pump current Ip and used.
この従来の空燃比センサは、酸素ポンプ素子と酸素ガス
検出素子との界面近傍の空燃比λを検出するために、基
準酸素源が不要な酸素ガス検出素子を使用しているの
で、構成が簡単で製造が容易である。This conventional air-fuel ratio sensor uses an oxygen gas detection element that does not require a reference oxygen source in order to detect the air-fuel ratio λ near the interface between the oxygen pump element and the oxygen gas detection element, so the configuration is simple. It is easy to manufacture.
［考案が解決しようとする問題点］ しかし、上記特開昭６１−１９５３３８号の従来の空燃
比センサは、酸素ポンプ素子が酸素ガス濃度を調整する
位置と、酸素ガス検出素子が酸素ガス濃度を検出する位
置とが隔たっているため、応答が余り速くないという不
満がある。[Problems to be Solved by the Invention] However, in the conventional air-fuel ratio sensor disclosed in JP-A-61-195338, the oxygen pump element adjusts the oxygen gas concentration and the oxygen gas detection element detects the oxygen gas concentration. There is a complaint that the response is not so fast because it is far from the detection position.
すなわち、酸素ポンプ素子は、外部から酸素ガス検出素
子側の電極に酸素ガスを輸送したり、あるいは酸素ガス
検出素子側の電極近傍の酸素ガスを外部に輸送する。そ
のため、酸素ポンプ素子の酸素ガス検出素子側多孔質電
極近傍の酸素ガス濃度が先ず調整される。一方、酸素ガ
ス検出素子は、その電極間の金属酸化物の抵抗が変化す
ることで酸素ガスを検出するが、上記従来の空燃比セン
サでは、酸素ガス検出素子の２つの電極と酸素ポンプ素
子の電極とが並んで酸素ポンプ素子の一方の面に形成さ
れている。That is, the oxygen pump element transports the oxygen gas from the outside to the electrode on the oxygen gas detection element side, or transports the oxygen gas near the electrode on the oxygen gas detection element side to the outside. Therefore, the oxygen gas concentration near the oxygen gas detecting element side porous electrode of the oxygen pump element is first adjusted. On the other hand, the oxygen gas detection element detects oxygen gas by changing the resistance of the metal oxide between the electrodes, but in the above conventional air-fuel ratio sensor, two electrodes of the oxygen gas detection element and the oxygen pump element are used. The electrodes are formed side by side on one surface of the oxygen pump element.
そのため、酸素ポンプ素子にポンプ電流が通電されて生
じた酸素ガス濃度の変化は、多孔質電極、酸素ガス検出
素子等の多孔質体内を拡散・移動して酸素ガス検出素子
の検出部に伝わる。したがって、酸素ポンプ素子にポン
プ電流を通電してから、酸素ガス検出素子の検出部の雰
囲気が変化するまでに時間がかかり、上記空燃比センサ
の応答は速くないのである。Therefore, a change in the oxygen gas concentration caused by the pump current flowing through the oxygen pump element is diffused / moved in the porous body such as the porous electrode and the oxygen gas detection element, and transmitted to the detection section of the oxygen gas detection element. Therefore, it takes time from when the pump current is supplied to the oxygen pump element until the atmosphere of the detection portion of the oxygen gas detection element changes, and the response of the air-fuel ratio sensor is not fast.
［問題点を解決するための手段］ 本考案は、上記従来の空燃比センサの問題点を有利に解
決することを目的とし、次のような構成を採用した。[Means for Solving Problems] The present invention adopts the following configuration in order to advantageously solve the problems of the conventional air-fuel ratio sensor.
即ち、本考案の要旨とするところは、 固体電解質体の表裏面に一対の多孔質電極を有する酸素
ポンプ素子と、 周囲の酸素ガス分圧に対応して抵抗が変化する金属酸化
物からなる感ガス層を有し、上記酸素ポンプ素子に積層
された酸素ガス検出素子と、 該酸素ガス検出素子に積層され、上記酸素ガス検出素子
と周囲雰囲気とを拡散制限的に連通する多孔質層と、 を備えた空燃比センサにおいて、 上記酸素ポンプ素子の一方の電極を櫛状に形成するとと
もに、該櫛状の電極と上記酸素ガス検出素子用の一方の
電極とを共通とし、かつ上記酸素ガス検出素子用の他方
の電極を上記共通の電極の櫛歯間に挿入するように、上
記酸素ポンプ素子の固体電解質体上に電気絶縁性セラミ
ック層を介して積層し、更に、該電気絶縁性セラミック
層の電極積層面と上記共通の電極が積層される面とがほ
ぼ同一平面になるように形成したことを特徴とした空燃
比センサにある。That is, the gist of the present invention is that a sensor made of an oxygen pump element having a pair of porous electrodes on the front and back surfaces of a solid electrolyte body and a metal oxide whose resistance changes according to the partial pressure of oxygen gas in the surroundings. An oxygen gas detection element having a gas layer, which is laminated on the oxygen pump element, and a porous layer which is laminated on the oxygen gas detection element and communicates the oxygen gas detection element and the ambient atmosphere in a diffusion-limited manner, In the air-fuel ratio sensor, the one electrode of the oxygen pump element is formed in a comb shape, the comb-shaped electrode and the one electrode for the oxygen gas detection element are commonly used, and the oxygen gas detection is performed. The other electrode for the element is laminated on the solid electrolyte body of the oxygen pump element via an electrically insulating ceramic layer so as to be inserted between the comb teeth of the common electrode, and further, the electrically insulating ceramic layer. Electrode product In the air-fuel ratio sensors, characterized in that the plane surface and the common electrode are stacked is formed to be substantially flush.
ここで、板状酸素ポンプ素子としては、前述の特開昭６
１−１９５３３８号に記載されるように、板状の酸素イ
オン伝導性固体電解質の両面に多孔質電極を設けた素子
を用いればよい。Here, as the plate-shaped oxygen pump element, the above-mentioned Japanese Patent Laid-Open No.
As described in JP-A No. 1-195338, an element in which porous electrodes are provided on both surfaces of a plate-shaped oxygen ion conductive solid electrolyte may be used.
この酸素ポンプ素子は、酸素イオン伝導性固体電解質が
適当な温度条件（例えば、固体電解質がZrO2系固溶体の
場合４００℃以上）にあると、上記一対の多孔質電極間
に電圧をかけることにより固体電解質中を酸素イオンが
移動する性質を利用する。This oxygen pump element, when the oxygen ion conductive solid electrolyte is in an appropriate temperature condition (for example, 400 ° C. or higher when the solid electrolyte is a ZrO 2 -based solid solution), applies a voltage between the pair of porous electrodes. The property that oxygen ions move in the solid electrolyte is used.
即ち、この酸素ポンプ素子の一対の電極間に電圧を加え
ると、電極電位の低い方から高い方へ、酸素イオンが移
動するために、電極電位の低い側では酸素ガス分圧が減
少し、逆に電極電位の高い側では酸素ガス分圧が増加す
る。また、上記固体電解質の荷電担体は酸素イオンであ
るために、上記電極間に流れる電流量を調節することに
より、酸素イオンの移動量を調節することができる。That is, when a voltage is applied between a pair of electrodes of this oxygen pump element, oxygen ions move from the lower electrode potential to the higher electrode potential, so that the oxygen gas partial pressure decreases on the lower electrode potential side, and On the side where the electrode potential is high, the oxygen gas partial pressure increases. Further, since the charge carrier of the solid electrolyte is oxygen ions, the amount of movement of oxygen ions can be adjusted by adjusting the amount of current flowing between the electrodes.
上記の酸素イオン伝導性固体電解質としては、ZrO2とY2
O3あるいはCaOとの固溶体が代表的なものである。その
他にも二酸化セリウム、二酸化トリウム、二酸化ハフニ
ウムの各固溶体、ペロブスカイト型酸化物固溶体、３価
金属酸化物固溶体等がこの酸素イオン導電性固体電解質
として使用可能である。As the above oxygen ion conductive solid electrolyte, ZrO 2 and Y 2
A typical solid solution is O 3 or CaO. In addition, cerium dioxide, thorium dioxide, hafnium dioxide solid solutions, perovskite type oxide solid solutions, trivalent metal oxide solid solutions and the like can be used as the oxygen ion conductive solid electrolyte.
多孔質電極は、Ｐｔ、Ｒｕ、Ｐｄ、Ｒｈ、Ｉｒ、Ａｇ、
Ａｕ等の耐熱性に優れる金属をフレーム溶射、化学メッ
キ、蒸着あるいは上記金属のペーストをプリント印刷焼
結する等の方法により形成すればよい。The porous electrode is composed of Pt, Ru, Pd, Rh, Ir, Ag,
A metal having excellent heat resistance such as Au may be formed by a method such as flame spraying, chemical plating, vapor deposition, or print-sintering of a paste of the above metal.
上記酸素ガス検出素子としては遷移金属酸化物を用いれ
ばよい。これらは金属元素と酸素の比が整数ではない非
化学量論的化合物となりやすいものである。この非化学
量論のために、これらの酸化物は周囲の酸素分圧によっ
て導電率が変化し易くなるのである。中でもTiO2、Co
O、SnO2，ZnO、Nb2O5，Cr2O3は、酸素分圧の変化に対す
る導電率変化が大きいこと、耐久性に優れること等の点
から好ましい。A transition metal oxide may be used as the oxygen gas detection element. These are likely to be non-stoichiometric compounds in which the ratio of metal element to oxygen is not an integer. Because of this non-stoichiometry, these oxides are susceptible to changes in conductivity due to the ambient oxygen partial pressure. Among them, TiO 2 and Co
O, SnO 2 , ZnO, Nb 2 O 5 and Cr 2 O 3 are preferable from the viewpoints of large change in conductivity with respect to changes in oxygen partial pressure and excellent durability.
［作用・効果］ 本考案の空燃比センサでは、酸素ガス検出素子の一方の
電極と酸素ポンプ素子の一方の電極とが共通部材（以下
その電極を共通電極と称す）とされるとともに、上記酸
素ガス検出電極の他方の電極（２０ａ）は、上記一方の
電極である共通電極（１０ｅ）と酸素ポンプ素子の固体
電解質体の表面上に並べて配置されるために、酸素ポン
プ素子によって酸素ガス濃度が調節される位置と、酸素
ガス検出素子の酸素ガス濃度の検出位置とが一致し、応
答性が向上する。[Operation / Effect] In the air-fuel ratio sensor of the present invention, one electrode of the oxygen gas detection element and one electrode of the oxygen pump element serve as a common member (hereinafter, the electrode is referred to as a common electrode) and The other electrode (20a) of the gas detection electrode is arranged side by side on the surface of the solid electrolyte body of the oxygen pump element with the common electrode (10e) which is the above-mentioned one electrode. The adjusted position coincides with the oxygen gas concentration detection position of the oxygen gas detection element, and the responsiveness is improved.
また同時に、この共通電極の構成によって、従来の空燃
比センサよりも電極の数が減り高価な電極材料の節約が
果たされ、かつ又、構成も簡素化されるという顕著な効
果を奏する。At the same time, the configuration of the common electrode has a remarkable effect that the number of electrodes is reduced as compared with the conventional air-fuel ratio sensor, the expensive electrode material is saved, and the configuration is simplified.
また、本考案では、上記共通電極が櫛状にされるととも
に、その共通電極の櫛歯間に挿入するように酸素ガス検
出素子の他方の電極が形成されるために、それらの電極
間の感ガス作用性部分が少なくとも２つ以上形成され、
かつ該部分には相互に均等な被感ガス用雰囲気が形成さ
れるようになり、安定した出力性能が得られる。Further, in the present invention, since the common electrode is formed into a comb shape and the other electrode of the oxygen gas detection element is formed so as to be inserted between the comb teeth of the common electrode, the sense between the electrodes is formed. At least two or more gas-activatable parts are formed,
At the same time, the atmospheres for the sensitive gas are formed mutually uniformly, so that stable output performance can be obtained.
更に、本考案では、燃焼排ガスと直接的に接触する側か
ら、感ガス層，共通電極及び酸素ガス検出素子の他方の
電極，固体電解質体，酸素ポンプ素子の他方の電極の順
に積層されていて、酸素ガス検出素子の１対の電極は、
感ガス層と固体電解質体との間に挟まれた構成であるた
めに、酸素ガス検出素子の電極にカーボン等が付着しに
くく、該電極の劣化やその性能の低下を防止する。Further, in the present invention, the gas sensing layer, the common electrode, the other electrode of the oxygen gas detection element, the solid electrolyte body, and the other electrode of the oxygen pump element are laminated in this order from the side in direct contact with the combustion exhaust gas. , The pair of electrodes of the oxygen gas detection element is
Since the structure is sandwiched between the gas sensitive layer and the solid electrolyte body, carbon or the like is less likely to adhere to the electrode of the oxygen gas detection element, and deterioration of the electrode and its performance are prevented.
更にまた、共通電極と酸素ガス検出素子の他方の電極と
の間には隙間部分があり、この隙間部分では、感ガス層
と固体電解質体とが直接に接触するが、感ガス層と固体
電解質体とは同じセラミックス同士であるので、その接
合性が良好で接合強度が高く、またその結果、感ガス層
と共通電極及び上記他方の電極との電気的接続が良好に
保持される。Furthermore, there is a gap between the common electrode and the other electrode of the oxygen gas detection element. In this gap, the gas-sensitive layer and the solid electrolyte body are in direct contact with each other. Since the body is made of the same ceramics, the bondability is good and the bond strength is high, and as a result, the electrical connection between the gas sensitive layer and the common electrode and the other electrode is well maintained.
その上、本考案の空燃比センサを製造する際には、１つ
の基板上に厚膜印刷によって容易に電極を形成でき、更
にそれを同時焼成することによって、簡単，正確かつ安
定強固に空燃比センサを製造できるという効果がある。Moreover, when manufacturing the air-fuel ratio sensor of the present invention, the electrodes can be easily formed on one substrate by thick film printing, and by co-firing the electrodes, the air-fuel ratio can be easily, accurately, stably and firmly. There is an effect that a sensor can be manufactured.
［実施例］ 本考案の一実施例を図を用いて説明する。本考案はこれ
に限られるものではなく、その要旨を逸脱しない範囲の
種々の態様のものが含まれる。[Embodiment] An embodiment of the present invention will be described with reference to the drawings. The present invention is not limited to this, and includes various embodiments without departing from the scope of the invention.
本実施例の空燃比センサの構成を第１図の部分破断斜視
図、第２図の分解斜視図を用いて説明する。The structure of the air-fuel ratio sensor of this embodiment will be described with reference to the partially broken perspective view of FIG. 1 and the exploded perspective view of FIG.
本空燃比センサは、酸素イオン伝導性固体電解質である
ZrO2系固溶体を用いた酸素ポンプ素子１０と、周囲の酸
素ガス分圧によってその抵抗値が変化するTiO2を用いた
酸素ガス検出素子２０と、該酸素ガス検出素子２０を覆
う多孔質ガス拡散制限部３０とを備える空燃比センサで
ある。This air-fuel ratio sensor is an oxygen ion conductive solid electrolyte
Oxygen pump element 10 using a ZrO 2 -based solid solution, oxygen gas detection element 20 using TiO 2 whose resistance value changes depending on the surrounding oxygen gas partial pressure, and porous gas diffusion covering the oxygen gas detection element 20. The air-fuel ratio sensor includes a limiting unit 30.
上記酸素ポンプ素子１０は、厚さ０．７mm×巾４mm×長
さ３５mmのZrO2系固体電解質焼結板状体１０ａと、板状
体１０ａの先側の一方の面で先側の三方の端縁から少し
控えた位置に櫛形に設けられたＰｔ製多孔質電極１０ｂ
と、上記板状体１０ａの他方の面で上記多孔質電極１０
ｂと同形状の櫛形開口部を有するここではAl2O3製の電
気絶縁性セラミック層１０ｃおよび該櫛形開口部に充填
されるZrO2系固体電解質層１０ｄと、該固体電解質層１
０ｄおよび上記板状体１０ａを介して上記多孔質電極１
０ｂに相対する櫛形のＰｔ製多孔質電極１０ｅと、上記
多孔質電極１０ｂ，１０ｅより上記板状体１０ａの元側
へまっすぐに伸びる帯形状のＰｔ製引出し線１０ｆ，１
０ｇと、上記多孔質電極１０ｂのZrO2製保護層１０ｈお
よび上記引出し線１０ｆのAl2O3製保護層１０ｉとを備
える。The oxygen pump element 10 includes a ZrO 2 -based solid electrolyte sintered plate body 10a having a thickness of 0.7 mm, a width of 4 mm, and a length of 35 mm, and one of the front side surfaces of the plate body 10a. Pt-made porous electrode 10b provided in a comb shape at a position slightly away from the edge
And the porous electrode 10 on the other surface of the plate-shaped body 10a.
Here, an electrically insulating ceramic layer 10c made of Al 2 O 3 having a comb-shaped opening of the same shape as b, a ZrO 2 -based solid electrolyte layer 10d filled in the comb-shaped opening, and the solid electrolyte layer 1 are provided.
0d and the plate-shaped body 10a, and the porous electrode 1
0b and a Pt-made porous electrode 10e in a comb shape, and a strip-shaped Pt lead wire 10f, 1 extending straight from the porous electrodes 10b, 10e to the original side of the plate-shaped body 10a.
0 g, a protective layer 10 h made of ZrO 2 of the porous electrode 10 b, and a protective layer 10 i made of Al 2 O 3 of the lead wire 10 f.
上記酸素ガス検出素子２０は、上記酸素ポンプ素子１０
の多孔質電極１０ｅと、上記絶縁層１０ｃ上で上記多孔
質電極１０ｅと噛み合うように対向して設けられた櫛形
のＰｔ製多孔質電極２０ａと、Al2O3製絶縁層２０ｂお
よびZrO2製基板２０ｃの窓部２０ｄ内で上記多孔質電極
１０ｅ，２０ａを覆うTiO2製感ガス層２０ｅと、多孔質
電極２０ａより板状体１０ａの元側へまっすぐに伸びる
帯形状の耐熱金属層の引出し線２０ｆとを備える。The oxygen gas detection element 20 is the oxygen pump element 10
Porous electrode 10e, a comb-shaped porous electrode 20a made of Pt and provided on the insulating layer 10c so as to face each other so as to mesh with the porous electrode 10e, an insulating layer 20b made of Al 2 O 3 , and an insulating layer 20b made of ZrO 2 . Extraction of a TiO 2 gas sensitive layer 20e that covers the porous electrodes 10e and 20a in the window 20d of the substrate 20c, and a band-shaped heat-resistant metal layer that extends straight from the porous electrode 20a to the original side of the plate 10a. And a line 20f.
また、多孔質ガス拡散制限部３０は、上記ZrO2製基板２
０ｃの窓部２０ｄ内で、上記感ガス層２０ｅを覆うTiO2
製多孔質層である。この拡散制限部３０の気孔率は上記
感ガス層２０ｅの気孔率より低く設定されるため、周囲
雰囲気と上記多孔質電極１０ｅ，２０ａ近傍との間は、
拡散制限的に連通する。尚、この気孔率は、特開昭６２
−１５０１５６号に記載される如く、空燃比センサの製
造後に、多孔質ガス拡散制限部３０へ硝酸アルミニウム
水溶液、塩化白金酸塩水溶液等を滴下し、焼成すること
により調節が可能である。Further, the porous gas diffusion limiting portion 30 is formed by using the ZrO 2 substrate 2
TiO 2 covering the gas sensitive layer 20e in the window 20d of 0c
It is a porous layer. Since the porosity of the diffusion limiting portion 30 is set lower than the porosity of the gas sensitive layer 20e, between the ambient atmosphere and the vicinity of the porous electrodes 10e, 20a,
Communication is limited to diffusion. Incidentally, this porosity is calculated according to JP-A-62-62
As described in JP-A-150156, after the production of the air-fuel ratio sensor, an aqueous solution of aluminum nitrate, an aqueous solution of chloroplatinate or the like is dropped into the porous gas diffusion limiting portion 30 and the mixture can be adjusted.
さらに、本空燃比センサは、上記櫛形の電極１０ｅの周
囲に発熱体４０を備える。Further, the air-fuel ratio sensor includes a heating element 40 around the comb-shaped electrode 10e.
本空燃比センサは、以下のように製造される。This air-fuel ratio sensor is manufactured as follows.
先ず、ZrO2ペースト、Al2O3ペースト、Ｐｔペースト、T
iO2ペーストを調整する。First, ZrO 2 paste, Al 2 O 3 paste, Pt paste, T
Adjust iO 2 paste.
（１）ZrO2ペーストの調整 （１）−ZrO2（９４モル％）とY2O3（６モル％）を、
湿式にて４０時間混合粉砕する。(1) Preparation of ZrO 2 paste (1) -ZrO 2 (94 mol%) and Y 2 O 3 (6 mol%)
Mix and grind for 40 hours in a wet manner.
（１）−この混合粉砕物を乾燥後、１３００℃で２時
間仮焼する。(1) -The mixed pulverized product is dried and then calcined at 1300 ° C. for 2 hours.
（１）−この仮焼物を、湿式にて４０時間粉砕し、固
体電解質原料粉末を得る。(1) -This calcined product is pulverized by a wet method for 40 hours to obtain a solid electrolyte raw material powder.
（１）−固体電解質原料粉末に、有機バインダー、メ
チルエチルケトン、トルエン等を添加し、ZrO2ペースト
とする。(1) -A ZrO 2 paste is prepared by adding an organic binder, methyl ethyl ketone, toluene, etc. to the solid electrolyte raw material powder.
（２）Al2O3ペーストの調整 （２）−Al2O392wt％、ＭｇＯ３wt％、及び焼結助剤
（ＳｉＯ２、ＣａＯ等）５wt％をポットミルにて２０時
間混合する。(2) Adjustment of the Al 2 O 3 paste (2) -Al 2 O 3 92wt %, MgO3wt%, and sintering aid and (SiO 2, CaO, etc.) 5 wt% mixed for 20 hours at a pot mill.
（２）−この混合物に有機バインダーとしてポリビニ
ールブチラール１２wt％、フタル酸ジブチル４wt％を添
加し、溶剤としてメチルエチルケトン、トルエン等を加
え、更にポットミルで１５時間混合してAl2O3ペースト
とする。(2) -Add 12 wt% of polyvinyl butyral and 4 wt% of dibutyl phthalate as an organic binder to this mixture, add methyl ethyl ketone, toluene, etc. as a solvent, and further mix with a pot mill for 15 hours to form an Al 2 O 3 paste.
（３）Ｐｔペーストの調整 白金黒とスポンジ状白金とを２：１の割合に混合物に、
溶剤、粘結材を加え、電極用のＰｔペーストを得る。(3) Preparation of Pt paste Platinum black and sponge-like platinum were mixed in a ratio of 2: 1,
A solvent and a binder are added to obtain a Pt paste for electrodes.
（４）TiO2ペーストの調整 大気中１２００℃で１時間仮焼したTiO2粉末に対し、バ
インダーとしてエチルセルロースを添加し、これらをブ
チカルビトール（２−（２−ブトキシエトキシ）エタノ
ールの商品名）中で混合し、TiO2ペーストを得る。この
TiO2ペーストは、感ガス層２０ｅ用の大きい粒径のTiO2
粉末を用いたものと、拡散制限部３０用の細かい粒径の
TiO2粉末を用いたものの２種類調整する。(4) Preparation of TiO 2 paste Ethyl cellulose was added as a binder to TiO 2 powder that was calcined in the air at 1200 ° C. for 1 hour, and these were added to butycarbitol (trade name of 2- (2-butoxyethoxy) ethanol). Mix in to obtain TiO 2 paste. this
The TiO 2 paste is a large particle size TiO 2 for the gas sensitive layer 20e.
One that uses powder and one that has a fine particle size
Two types of TiO 2 powder are prepared.
続いて、以下のようにして空燃比センサを形成する。Then, the air-fuel ratio sensor is formed as follows.
（５）上記ZrO2ペーストからドクターブレード法によ
り、０．８mm厚の板状体１０ａとなるZrO2グリーンシー
トを得る。(5) A ZrO 2 green sheet to be a 0.8 mm-thick plate-shaped body 10a is obtained from the ZrO 2 paste by a doctor blade method.
（６）このZrO2グリーンシートの一方の面に、上記Ｐｔ
ペーストを用いて、第２図に示す多孔質電極１０ｂ，引
出し線１０ｆのパターンをスクリーン印刷で３０μｍ厚
に形成する。そして、上記ZrO2ペーストを用いて多孔質
電極１０ｂの保護層１０ｈを形成し、上記Al2O3ペース
トを用いて引出し線１０ｆの保護層１０ｉを形成する。(6) On one surface of the ZrO 2 green sheet, the Pt
The paste is used to form the pattern of the porous electrode 10b and the lead wire 10f shown in FIG. 2 by screen printing to a thickness of 30 μm. Then, the protective layer 10h of the porous electrode 10b is formed by using the ZrO 2 paste, and the protective layer 10i of the lead wire 10f is formed by using the Al 2 O 3 paste.
（７）ついで、このZrO2グリーンシートの他方の面に、
上記Al2O3ペーストを用いて第２図に示す電気絶縁性セ
ラミック層１０ｃおよび上記ZrO2ペーストを用いて第２
図に示す固体電解質層１０ｄを形成する。(7) Then, on the other side of this ZrO 2 green sheet,
The Al 2 O 3 paste is used for the electrically insulating ceramic layer 10c shown in FIG. 2 and the ZrO 2 paste is used for the second
A solid electrolyte layer 10d shown in the figure is formed.
（８）さらに、この絶縁層１０ｃおよび固体電解質層１
０ｄ上に、上記Ｐｔペーストを用いて第２図に示す多孔
質電極１０ｅ，２０ａ、引出し線１０ｇ，２０ｆおよび
発熱体４０の各パターンをスクリーン印刷で３０μｍ厚
に形成する。(8) Furthermore, the insulating layer 10c and the solid electrolyte layer 1
Each pattern of the porous electrodes 10e, 20a, the lead wires 10g, 20f and the heating element 40 shown in FIG. 2 is formed on the surface 0d by screen printing to a thickness of 30 μm using the Pt paste.
（９）そして、この電極パターンに重ねて、上記Al2O3
ペーストを用いた絶縁層２０ｂ、ZrO2ペーストにより作
成した開口部２０ｄを有するZrO2グリーンシート２０ｃ
を積層圧着する。(9) Then, overlaying on this electrode pattern, the above Al 2 O 3
Insulating layer 20b made of paste, ZrO 2 green sheet 20c having openings 20d made of ZrO 2 paste
Laminate and crimp.
（１０）上記積層体を、３００℃、６時間で樹脂抜きを
行った後、大気中雰囲気中、１５００℃、４時間の条件
で焼成する。(10) After removing the resin from the laminate at 300 ° C. for 6 hours, it is fired in the atmosphere at 1500 ° C. for 4 hours.
（１１）続いて、上記焼成体の開口部２０ｄに、感ガス
層２０ｅとなる上記大きいTiO2粉末を用いたTiO2ペース
トを厚膜印刷技術で充填し、次いで、この充填層に重ね
てガス拡散制限部３０となる上記小さいTiO2粉末を用い
たTiO2ペーストを厚膜印刷技術で充填する。(11) Subsequently, the opening 20d of the fired body is filled with a TiO 2 paste using the large TiO 2 powder to be the gas-sensitive layer 20e by a thick film printing technique, and then the filled layer is overlaid with a gas. The TiO 2 paste using the above-mentioned small TiO 2 powder to be the diffusion limiting portion 30 is filled by a thick film printing technique.
（１２）その後、上記工程を終えた積層体を１２００℃
大気中に１時間放置して焼成して、本実施例の空燃比セ
ンサを得る。(12) Thereafter, the laminated body that has undergone the above steps is heated to 1200 ° C.
The air-fuel ratio sensor of this embodiment is obtained by leaving it in the air for 1 hour and firing it.
以上説明したように、本実施例の空燃比センサは、酸素
ポンプ素子１０の一方の多孔質電極１０ｅを酸素ガス検
出素子２０の一方の多孔質電極としても使用するととも
に、上記酸素ガス検出素子の他方の電極２０ａは、上記
一方の電極１０ｅと酸素ポンプ素子の固体電解質体の表
面上に並べて配置したため、酸素ポンプ素子１０によっ
て酸素ガス濃度が調整される位置と、酸素ガス検出素子
の酸素ガス濃度の検出位置とが一致し、空燃比センサの
応答が速くなると同時に、電極材料の節約ができ、かつ
構成もより簡素化される。As described above, in the air-fuel ratio sensor of the present embodiment, the one porous electrode 10e of the oxygen pump element 10 is also used as one porous electrode of the oxygen gas detection element 20, and the oxygen gas detection element The other electrode 20a is arranged side by side on the one electrode 10e and the surface of the solid electrolyte body of the oxygen pump element, so that the oxygen gas concentration is adjusted by the oxygen pump element 10 and the oxygen gas concentration of the oxygen gas detection element. Coincides with the detection position of, and the response of the air-fuel ratio sensor becomes faster, and at the same time, the electrode material can be saved, and the configuration is further simplified.
また、共通電極１０ｅと酸素ガス検出素子の他方の電極
２０ａとを櫛状とし、上記共通電極１０ｅの櫛歯間に上
記他方の電極２０ａを挿入するようにして感ガス作用性
の電極間部分（４つ）形成を形成したので、より安定し
た出力性能が得られる。In addition, the common electrode 10e and the other electrode 20a of the oxygen gas detection element are formed in a comb shape, and the other electrode 20a is inserted between the comb teeth of the common electrode 10e so that the gas-sensitive interelectrode portion ( 4) Since the formation is performed, more stable output performance is obtained.
また更に、本実施例では、周囲雰囲気に（多孔質ガス拡
散制限部３０を介して）接する側から、感ガス層２０
ｅ，両多孔質電極１０ｅ，２０ａ，固体電解質層１０
ｄ，多孔質電極１０ｂの順に積層されていて、感ガス層
のための多孔質電極１０ｅ，２０ａは、感ガス層２０ｅ
と固体電解質層１０ｄとの間に挟まれた構成となってい
るため、この多孔質電極１０ｅにカーボン等が付着しに
くく、電極の劣化や性能の低下を防止することができ
る。Furthermore, in the present embodiment, the gas-sensitive layer 20 is contacted with the ambient atmosphere (through the porous gas diffusion limiting portion 30).
e, both porous electrodes 10e, 20a, solid electrolyte layer 10
d and the porous electrode 10b are laminated in this order, and the porous electrodes 10e and 20a for the gas sensitive layer are the gas sensitive layer 20e.
Since it is sandwiched between the solid electrolyte layer 10d and the solid electrolyte layer 10d, carbon or the like is less likely to adhere to the porous electrode 10e, and deterioration of the electrode and deterioration of performance can be prevented.
また、両多孔質電極１０ｅ，２０ａの間には、絶縁のた
めに隙間があり、この隙間部分では、感ガス層２０ｅと
固体電解質層１０ｄとが直接に接触するが、感ガス層２
０ｅと固体電解質層１０ｄとは同じセラミックス同士で
あるので、その接合性が良好で接合強度が高い。またそ
の結果、感ガス層２０ｅ多孔質電極１０ｅ，２０ａとの
電気的接触状態も良好に維持される。Further, there is a gap between the two porous electrodes 10e and 20a for insulation, and the gas-sensitive layer 20e and the solid electrolyte layer 10d are in direct contact with each other in this gap, but the gas-sensitive layer 2
Since 0e and the solid electrolyte layer 10d are the same ceramics, their bondability is good and their bond strength is high. As a result, the electrical contact state with the gas-sensitive layer 20e and the porous electrodes 10e and 20a is also favorably maintained.
その上、本実施例の空燃比センサを製造する際には、１
つの基板上に厚膜印刷によって容易に電極１０ｅ，２０
ａ等を形成でき、更にそれを同時焼成することによっ
て、簡単、正確かつ安定強固に空燃比センサを製造でき
るという効果がある。In addition, when manufacturing the air-fuel ratio sensor of this embodiment, 1
The electrodes 10e, 20 can be easily formed on one substrate by thick film printing.
By forming a and the like and further firing them simultaneously, there is an effect that an air-fuel ratio sensor can be manufactured easily, accurately and stably.
第１図は本考案の一実施例の破断斜視図、第２図はその
分解斜視図である。 １０……酸素ポンプ素子、 １０ａ……固体電解質焼結板状体、 １０ｂ……多孔質電極、 １０ｃ……電気絶縁性セラミック層、 １０ｅ……多孔質電極（酸素ガス検出素子の一方の多孔
質電極を兼ねる）、 ２０……酸素ガス検出素子、 ２０ａ……多孔質電極、 ２０ｅ……感ガス層、 ３０……多孔質ガス拡散制限部FIG. 1 is a cutaway perspective view of an embodiment of the present invention, and FIG. 2 is an exploded perspective view thereof. 10 ... Oxygen pump element, 10a ... Solid electrolyte sintered plate, 10b ... Porous electrode, 10c ... Electrically insulating ceramic layer, 10e ... Porous electrode (one porous of the oxygen gas detection element) Also serves as an electrode), 20 ... Oxygen gas detection element, 20a ... Porous electrode, 20e ... Gas sensitive layer, 30 ... Porous gas diffusion limiting section
Claims (3)
を有する酸素ポンプ素子と、周囲の酸素ガス分圧に対応
して抵抗が変化する金属酸化物からなる感ガス層を有
し、上記酸素ポンプ素子に積層された酸素ガス検出素子
と、 該酸素ガス検出素子に積層され、上記酸素ガス検出素子
と周囲雰囲気とを拡散制限的に連通する多孔質層と、 を備えた空燃比センサにおいて、 上記酸素ポンプ素子の一方の電極を櫛状に形成するとと
もに、該櫛状の電極と上記酸素ガス検出素子用の一方の
電極とを共通とし、かつ上記酸素ガス検出素子用の他方
の電極を上記共通の電極の櫛歯間に挿入するように、上
記酸素ポンプ素子の固体電解質体上に電気絶縁性セラミ
ック層を介して積層し、更に、該電気絶縁性セラミック
層の電極積層面と上記共通の電極が積層される面とがほ
ぼ同一平面になるように形成したことを特徴とした空燃
比センサ。1. An oxygen pump element having a pair of porous electrodes on the front and back surfaces of a solid electrolyte body, and a gas sensitive layer made of a metal oxide whose resistance changes according to the partial pressure of oxygen gas in the surroundings. An air-fuel ratio sensor comprising: an oxygen gas detection element laminated on the oxygen pump element; and a porous layer laminated on the oxygen gas detection element and communicating the oxygen gas detection element with the ambient atmosphere in a diffusion-limited manner. In which one electrode of the oxygen pump element is formed in a comb shape, and the comb-shaped electrode and one electrode for the oxygen gas detection element are shared, and the other electrode for the oxygen gas detection element is formed. So as to be inserted between the comb teeth of the common electrode via the electrically insulating ceramic layer on the solid electrolyte body of the oxygen pump element, and further, the electrode laminated surface of the electrically insulating ceramic layer and the above Common electrodes stacked Air-fuel ratio sensors, characterized in that the surface to be is formed to be substantially flush.
実用新案登録請求の範囲第１項記載の空燃比センサ。2. The air-fuel ratio sensor according to claim 1, wherein the solid electrolyte body is a ZrO 2 type solid solution.
2O5，V2O5，Cr2O3，CoO及びNiOから選ばれた１種又は２
種以上からなる実用新案登録請求の範囲第１項または第
２項いずれか記載の空燃比センサ。3. The oxygen gas detecting element comprises SnO 2 , TiO 2 , Nb
1 or 2 selected from 2 O 5 , V 2 O 5 , Cr 2 O 3 , CoO and NiO
The air-fuel ratio sensor according to claim 1 or 2, which comprises at least one kind of utility model.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1987155660U JPH0631423Y2 (en) | 1987-10-12 | 1987-10-12 | Air-fuel ratio sensor |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1987155660U JPH0631423Y2 (en) | 1987-10-12 | 1987-10-12 | Air-fuel ratio sensor |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH0159859U JPH0159859U (en) | 1989-04-14 |
| JPH0631423Y2 true JPH0631423Y2 (en) | 1994-08-22 |
Family
ID=31433485
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP1987155660U Expired - Lifetime JPH0631423Y2 (en) | 1987-10-12 | 1987-10-12 | Air-fuel ratio sensor |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH0631423Y2 (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2009113250A1 (en) * | 2008-03-12 | 2009-09-17 | パナソニック株式会社 | Thin-film electrode, and measuring cell and inspecting device having the electrode |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS61264245A (en) * | 1985-05-17 | 1986-11-22 | Nissan Motor Co Ltd | Oxygen sensor |
| JPS62106355A (en) * | 1985-11-05 | 1987-05-16 | Tech Res Assoc Conduct Inorg Compo | Sensor for controlling combustion |
-
1987
- 1987-10-12 JP JP1987155660U patent/JPH0631423Y2/en not_active Expired - Lifetime
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2009113250A1 (en) * | 2008-03-12 | 2009-09-17 | パナソニック株式会社 | Thin-film electrode, and measuring cell and inspecting device having the electrode |
Also Published As
| Publication number | Publication date |
|---|---|
| JPH0159859U (en) | 1989-04-14 |
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