JPH0410983B2 - - Google Patents
Info
- Publication number
- JPH0410983B2 JPH0410983B2 JP59072238A JP7223884A JPH0410983B2 JP H0410983 B2 JPH0410983 B2 JP H0410983B2 JP 59072238 A JP59072238 A JP 59072238A JP 7223884 A JP7223884 A JP 7223884A JP H0410983 B2 JPH0410983 B2 JP H0410983B2
- Authority
- JP
- Japan
- Prior art keywords
- air
- oxygen
- fuel ratio
- solid electrolyte
- pump
- 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 - Lifetime
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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
-
- 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
- G01N27/4065—Circuit arrangements specially adapted therefor
Landscapes
- 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)
- 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〕
本発明は機関の空燃比センサに係り、特に理論
空燃比以外の空燃比の検出が可能となる空燃比セ
ンサに関する。DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an air-fuel ratio sensor for an engine, and particularly to an air-fuel ratio sensor that is capable of detecting an air-fuel ratio other than the stoichiometric air-fuel ratio.
従来の電気抵抗変化形酸素センサとしては、チ
タニア（TiO2）センサが公知であるが、これは
理論空燃比を境として抵抗値が急変する理論空燃
比センサというべきもので、理論空燃比だけしか
検出できず、広い範囲にわたつての空燃比の検出
ができないという問題があつた。
A titania (TiO 2 ) sensor is well known as a conventional electric resistance variable oxygen sensor, but this sensor is a stoichiometric air-fuel ratio sensor whose resistance value changes suddenly around the stoichiometric air-fuel ratio; There was a problem that the air-fuel ratio could not be detected over a wide range.
このため、特開昭58−148946号公報等に示され
るような空燃比検出器が従来既に提案されてい
る。すなわち、この空燃比検出器は、チタニア等
の遷移金属酸化物の表面に酸素イオン伝導性固体
電解質を電極間に侠んで設け、該酸素イオン導電
性固体電解質層を多孔性によるガス拡散層として
機能させ、その細孔中で酸素を移動させるように
構成するとともに、固体電解質層に電極を介して
電流を流すことで酸素イオンポンプとして機能さ
れることによつて、遷移金属酸化物の酸素分圧を
コントロールし、理論空燃比以外の空燃比、つま
りリーン及びリツチ空燃比の検出を可能としてい
るものであつた。 For this reason, air-fuel ratio detectors such as those disclosed in Japanese Patent Laid-Open No. 58-148946 and the like have already been proposed. That is, in this air-fuel ratio detector, an oxygen ion conductive solid electrolyte is provided on the surface of a transition metal oxide such as titania between electrodes, and the oxygen ion conductive solid electrolyte layer functions as a gas diffusion layer due to its porosity. The oxygen partial pressure of the transition metal oxide is reduced by making the solid electrolyte layer function as an oxygen ion pump by passing an electric current through the solid electrolyte layer through the electrodes. It was possible to control air-fuel ratios other than the stoichiometric air-fuel ratio, that is, to detect lean and rich air-fuel ratios.
しかしながら、上述した構成による空燃比検出
器によれば、酸素イオン導電性固体電解質層を多
孔性ガス拡散層として機能させ、その中に一体化
して形成される細孔中で酸素を、細孔による拡散
律速作用（Knudsen拡散）にて移動させているも
のであり、その細孔の精度や耐久性など、技術的
に困難な点があつた。さらに、上述した細孔によ
る拡散律速作用（Knudsen拡散）では、被測定ガ
ス（排気ガス）側の圧力に比例して影響を受ける
特性を持つており、圧力変動を生じる排気ガスで
の空燃比の検出を行なうにあたつて、精度的に問
題であり、このような問題点を一掃し得る何らか
の対策を講じることが望まれている。
However, according to the air-fuel ratio detector having the above-described configuration, the oxygen ion conductive solid electrolyte layer functions as a porous gas diffusion layer, and oxygen is absorbed into the pores formed integrally therein. It moves by diffusion-limiting action (Knudsen diffusion), and there were technical difficulties such as the precision and durability of the pores. Furthermore, the above-mentioned diffusion-limiting effect (Knudsen diffusion) due to pores has a characteristic that it is affected in proportion to the pressure on the measured gas (exhaust gas) side, and the air-fuel ratio in the exhaust gas, which causes pressure fluctuations, There is a problem with accuracy when performing detection, and it is desired that some kind of countermeasure be taken to eliminate such problems.
このような問題点を解決するために本発明に係
る空燃比センサは、平板状の固体電解質の両側面
に電極を設けることにより構成されている固体電
解質酸素ポンプと、平板状に構成されている電気
抵抗変化形酸素センサとを、微小間隙を介して対
向配置し、この微小間隙内に被測定ガスを導入す
るとともに、この微小間隙内に導入された被測定
ガスの酸素濃度を、酸素ポンプを用いて制御する
手段を備えてなる構成としたものである。
In order to solve these problems, the air-fuel ratio sensor according to the present invention includes a solid electrolyte oxygen pump configured by providing electrodes on both sides of a flat solid electrolyte, and a solid electrolyte oxygen pump configured by providing electrodes on both sides of a flat solid electrolyte. The electric resistance variable oxygen sensor and the oxygen sensor are placed opposite each other through a minute gap, and the gas to be measured is introduced into this minute gap, and the oxygen concentration of the gas to be measured introduced into this minute gap is measured using an oxygen pump. This configuration includes a means for controlling using the control.
本発明によれば、対向配置された平板状固体電
解質酸素ポンプと平板状電気抵抗型酸素センサと
の間の微小間隙内に、排気ガス等の被測定ガスを
導入することにより、この微小間隙内での排気ガ
ス中の酸素分圧を、酸素ポンプの作用で変化させ
ることにより、化学当量点を移動させ、これを排
気ガスの圧力の影響を受けない特性を持つている
微小間隙の拡散律速作用（Molecular拡散）で定
常化することによつて、排気ガス中の酸素濃度を
検出し、理論空燃比以外の空燃比、つまりリーン
及びリツチ空燃比の検出を可能としている。
According to the present invention, by introducing a gas to be measured such as exhaust gas into a minute gap between a flat solid electrolyte oxygen pump and a flat electrical resistance type oxygen sensor that are arranged opposite to each other, By changing the partial pressure of oxygen in the exhaust gas using the action of an oxygen pump, the chemical equivalence point is moved, and this is achieved by the diffusion-limiting effect of a micro gap that has the characteristic of not being affected by the pressure of the exhaust gas. (Molecular diffusion) makes it possible to detect the oxygen concentration in the exhaust gas and detect air-fuel ratios other than the stoichiometric air-fuel ratio, that is, lean and rich air-fuel ratios.
実施例 １
第１図は本発明に係る空燃比センサの一実施例
を示す構成図、第２図は第１図の−線断面図
である。これらの図において、１は機関の排気
管、２は排気管１内に配設された空燃比センサで
ある。この空燃比センサ２は、厚さが約0.5mmの
平板状固体電解質（安定化ジルコニア）３の両側
面に、それぞれ白金電極４および５を設けること
により構成されている固体電解質酸素ポンプ６
と、厚さが約0.5mmの絶縁性の平板８の片面に設
けられた電気抵抗変化形濃度検知体（チタニア；
TiO2）７の両端に、測定用リード線９および１
０を設けることにより構成されている抵抗変化形
酸素センサ１１と、これら酸素ポンプ６と酸素セ
ンサ１１を、0.1mm程度の微小間隙ｄを介して対
向配置するための支持台１２とによつて構成され
ている。１３は前記酸素ポンプ６を動作させて微
小間隙ｄ内の酸素濃度を変化させるためのポンプ
電流制御供給装置、１４は測定端子である。
Embodiment 1 FIG. 1 is a configuration diagram showing an embodiment of an air-fuel ratio sensor according to the present invention, and FIG. 2 is a sectional view taken along the line -- in FIG. In these figures, 1 is an exhaust pipe of the engine, and 2 is an air-fuel ratio sensor disposed within the exhaust pipe 1. This air-fuel ratio sensor 2 includes a solid electrolyte oxygen pump 6 which is constructed by providing platinum electrodes 4 and 5 on both sides of a flat solid electrolyte (stabilized zirconia) 3 with a thickness of approximately 0.5 mm.
An electric resistance variable concentration sensor (titania;
Measurement lead wires 9 and 1 are connected to both ends of TiO 2 )7.
0, and a support base 12 for arranging these oxygen pump 6 and oxygen sensor 11 facing each other with a minute gap d of about 0.1 mm in between. has been done. 13 is a pump current control supply device for operating the oxygen pump 6 to change the oxygen concentration within the minute gap d, and 14 is a measurement terminal.
そして、このような構成による空燃比センサに
よれば、上述したように対向配置されている平板
状固体電解質酸素ポンプ６と平板状電化抵抗型酸
素センサ１１との間の微小間隙ｄ内に、被測定ガ
スとして排気ガスを導入することで、この微小間
隙ｄ内での排気ガス中の酸素分圧を、酸素ポンプ
６の作用で変化させることによつて、化学当量点
を移動させ、これを排気ガスの圧力の影響を受け
ない特性を持つている微小間隙の拡散律速作用
（Molecular拡散）で定常化することにより、排
気ガス中の酸素濃度を検出し、理論空燃比以外の
空燃比、つまりリーン及びリツチ空燃比を検出し
得るものである。 According to the air-fuel ratio sensor having such a configuration, as described above, an air-fuel ratio sensor is provided in the minute gap d between the flat solid electrolyte oxygen pump 6 and the flat electrified resistance type oxygen sensor 11, which are arranged facing each other. By introducing the exhaust gas as the measurement gas, the oxygen partial pressure in the exhaust gas within this minute gap d is changed by the action of the oxygen pump 6, thereby moving the chemical equivalence point, and causing the exhaust gas to move. The oxygen concentration in the exhaust gas is detected by stabilizing it by the diffusion-limiting action (molecular diffusion) of micro gaps that are not affected by gas pressure, and detects air-fuel ratios other than the stoichiometric air-fuel ratio, that is, lean air-fuel ratios. and rich air-fuel ratio.
以上のように構成された本発明に係る空燃比セ
ンサを、たとえば国産乗用車2000c.c.のガソリン機
関に装着して試験した結果を、第３図に示してい
る。 FIG. 3 shows the results of a test in which the air-fuel ratio sensor according to the present invention configured as described above was installed in, for example, a gasoline engine of a domestic passenger car 2000c.c.
ここで、酸素ポンプ６を用いて微小間隙ｄの酸
素をくみ出す動作を行なうと、抵抗変化形酸素セ
ンサ１１の抵抗変化点が、図中ａのように理論空
燃比よりリーン側に移動し、ポンプ電流を増加す
ると、さらに図中ｂのようにリーン側へ移動し
た。一方、これとは逆に酸素をくみ込む動作を行
なうと、抵抗変化点が図中ｃのようにリツチ側へ
移動し、ポンプ電流を増加すると、図中ｄのよう
にさらにリツチ側に移動した。そして、このよう
な特性を利用することにより、上述した機関の運
転空燃比を検知し得ることになる。 Here, when the oxygen pump 6 is used to pump out oxygen from the minute gap d, the resistance change point of the variable resistance oxygen sensor 11 moves to the lean side from the stoichiometric air-fuel ratio, as shown in a in the figure. When the pump current was increased, it further moved to the lean side as shown in b in the figure. On the other hand, when oxygen is pumped in the opposite direction, the resistance change point moves to the rich side as shown in c in the figure, and when the pump current is increased, it moves further to the rich side as shown in d in the figure. . By utilizing such characteristics, the operating air-fuel ratio of the engine described above can be detected.
実施例 ２
第４図は本発明の第２の実施例を示す構成図、
第５図は第４図における−線断面図である。
これらの図において、図中１５は排気管１内に配
設された空燃比センサである。この空燃比センサ
１５は、外気と連通する空気室を持つ平板状固体
電解質（安定化ジルコニア）１６に、白金電極１
７および１８とを設けることにより構成されてい
る固体電解質酸素ポンプ１９と、前述した抵抗変
化形酸素センサ１１と、これら酸素ポンプ１９と
酸素センサ１１とを、0.1mm程度の微小間隙ｄ１
を介して対向配置させるための支持台２０とで構
成されている。なお、１３は上述した酸素ポンプ
１９を動作させて上述した微小間隙ｄ１内の酸素
濃度を変化させるためのポンプ電流制御供給装置
で、また１４は測定端子である。Embodiment 2 FIG. 4 is a configuration diagram showing a second embodiment of the present invention,
FIG. 5 is a sectional view taken along the - line in FIG. 4.
In these figures, reference numeral 15 denotes an air-fuel ratio sensor disposed within the exhaust pipe 1. This air-fuel ratio sensor 15 has a platinum electrode 1 on a flat solid electrolyte (stabilized zirconia) 16 having an air chamber communicating with the outside air.
7 and 18, the aforementioned variable resistance oxygen sensor 11, and the oxygen pump 19 and oxygen sensor 11 are separated by a micro gap d1 of about 0.1 mm.
and a support stand 20 for facing each other via the support stand 20. Note that 13 is a pump current control supply device for operating the oxygen pump 19 mentioned above to change the oxygen concentration in the minute gap d1, and 14 is a measurement terminal.
そして、以上のように構成されたこの酸素セン
サによつても、上述した実施例１と同等の作用結
果が得られることが確認されている。さらに、こ
の実施例での空燃比センサは、空気を酸素供給源
としているので、微小間隙ｄ１内に充分に酸素を
送り込むことが可能となり、前述した実施例１に
よる空燃比センサよりも、より一層空燃比が過濃
度（リツチ）となる空燃比を検知することが可能
となるものであつた。 It has been confirmed that this oxygen sensor configured as described above can also provide the same operational results as in Example 1 described above. Furthermore, since the air-fuel ratio sensor in this embodiment uses air as the oxygen supply source, it is possible to send sufficient oxygen into the minute gap d1, which is even better than the air-fuel ratio sensor according to the first embodiment described above. It was possible to detect an air-fuel ratio at which the air-fuel ratio becomes excessively rich.
すなわち、以上のように抵抗値変化点が移動す
る理由は、微小間隙ｄ，ｄ１内で導入された排気
ガス中の酸素分圧を、前記酸素ポンプ６，１９の
作用で変更することにより化学当量点を移動さ
せ、微小間隙の拡散律速作用（Molecular拡散）
で定常化されていると考えられ、その結果として
抵抗値変化点が移動するものである。 That is, the reason why the resistance value change point moves as described above is that the oxygen partial pressure in the exhaust gas introduced into the minute gaps d and d1 is changed by the action of the oxygen pumps 6 and 19, and the chemical equivalent is changed. By moving the point, the diffusion-limiting effect of microgap (Molecular diffusion)
It is considered that the resistance value is stabilized at , and as a result, the resistance value change point moves.
以上説明したように本発明に係る空燃比センサ
によれば、平板状の固体電解質の両側面に電極を
設けることで構成される固体電解質酸素ポンプ
と、平板状に構成される電気抵抗変化形酸素セン
サとを、微小間隙を介して対向配置し、この微小
間隙内に被測定ガスを導入するとともに、この微
小間隙内に導入された被測定ガスの酸素濃度を、
酸素ポンプを用いて制御する手段を備えてなる構
成としたので、簡単な構成にもかかわらず、微小
間隙内に導入される排気ガス中の酸素分圧を、酸
素ポンプの作用で変化させて、化学当量点を移動
させ、これを排気ガスの圧力の影響を受けない特
性を持つている微小間隙の拡散律速作用
（Molecular拡散）で定常化することにより、排
気ガス中の酸素濃度を検出し、理論空燃比以外の
空燃比、つまりリーン及びリツチ空燃比を適切か
つ確実に検出することが可能となり、これにより
実用性に優れた機関の空燃比センサを安価に得る
ことができるという種々優れた効果がある。特
に、上述した微小間隙の拡散律速作用
（Molecular拡散）は、排気ガスでの圧力の影響
を受けない特性を有しているため、空燃比の検出
精度を、大幅に向上させ得るという利点を奏する
ものである。
As explained above, the air-fuel ratio sensor according to the present invention includes a solid electrolyte oxygen pump configured by providing electrodes on both sides of a flat solid electrolyte, and a variable resistance oxygen pump configured in a flat solid electrolyte. The sensors are arranged opposite to each other through a minute gap, a gas to be measured is introduced into this minute gap, and the oxygen concentration of the gas to be measured introduced into this minute gap is measured.
Since the configuration is equipped with a control means using an oxygen pump, despite the simple configuration, the oxygen partial pressure in the exhaust gas introduced into the micro gap can be changed by the action of the oxygen pump. The oxygen concentration in the exhaust gas is detected by moving the chemical equivalence point and stabilizing it by the diffusion-limiting effect (molecular diffusion) of a micro gap, which has the characteristic of not being affected by the pressure of the exhaust gas. It has become possible to appropriately and reliably detect air-fuel ratios other than the stoichiometric air-fuel ratio, that is, lean and rich air-fuel ratios, and this has various excellent effects such as making it possible to obtain a highly practical engine air-fuel ratio sensor at a low cost. There is. In particular, the above-mentioned diffusion-limiting effect (molecular diffusion) in the microgap has the characteristic that it is not affected by the pressure in the exhaust gas, so it has the advantage of greatly improving the accuracy of detecting the air-fuel ratio. It is something.
第１図は本発明に係る空燃比センサの第１の実
施例を示す構成図、第２図は第１図の−線断
面図、第３図は2000c.c.のガソリン機関を用いて試
験して得られた特性図、第４図は本発明の第２の
実施例を示す構成図、第５図は第４図の−線
断面図である。
１……排気管、６，１９……固体電解質酸素ポ
ンプ、１１……電気抵抗変化形酸素センサ、１３
……ポンプ電流制御供給装置、ｄ，ｄ１……微小
間隙。
Fig. 1 is a configuration diagram showing a first embodiment of the air-fuel ratio sensor according to the present invention, Fig. 2 is a sectional view taken along the line - - of Fig. 1, and Fig. 3 is a test using a 2000 c.c. gasoline engine. FIG. 4 is a configuration diagram showing a second embodiment of the present invention, and FIG. 5 is a cross-sectional view taken along the line -- in FIG. 4. 1... Exhaust pipe, 6, 19... Solid electrolyte oxygen pump, 11... Electric resistance variable oxygen sensor, 13
...Pump current control supply device, d, d1...Minute gap.
Claims (1)
ことにより構成されている固体電解質酸素ポンプ
と、平板状に構成されている電気抵抗変化形酸素
センサとを、微小間隙を介して対向配置し、この
微小間隙内に被測定ガスを導入するように構成す
るとともに、前記微小間隙内に導入された被測定
ガスの酸素濃度を、前記酸素ポンプを用いて制御
する手段を備えたことを特徴とする空燃比セン
サ。 ２ 外気と連通する空気室を持つた平板状の固体
電解質酸素ポンプを備えてなり、空気を酸素供給
源として利用したことを特徴とする特許請求の範
囲第１項記載の空燃比センサ。[Scope of Claims] 1. A solid electrolyte oxygen pump configured by providing electrodes on both sides of a flat solid electrolyte and a variable resistance oxygen sensor configured in a flat plate with a micro gap between them. and a means for controlling the oxygen concentration of the gas to be measured introduced into the microgap using the oxygen pump. An air-fuel ratio sensor characterized by: 2. The air-fuel ratio sensor according to claim 1, comprising a flat solid electrolyte oxygen pump having an air chamber communicating with outside air, and using air as an oxygen supply source.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP59072238A JPS60216251A (en) | 1984-04-11 | 1984-04-11 | Air/fuel ratio sensor |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP59072238A JPS60216251A (en) | 1984-04-11 | 1984-04-11 | Air/fuel ratio sensor |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS60216251A JPS60216251A (en) | 1985-10-29 |
| JPH0410983B2 true JPH0410983B2 (en) | 1992-02-27 |
Family
ID=13483505
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP59072238A Granted JPS60216251A (en) | 1984-04-11 | 1984-04-11 | Air/fuel ratio sensor |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS60216251A (en) |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS61195338A (en) * | 1985-02-25 | 1986-08-29 | Ngk Spark Plug Co Ltd | Air fuel ratio sensor |
| JPS6296559U (en) * | 1985-12-07 | 1987-06-19 | ||
| JPH05852Y2 (en) * | 1985-12-16 | 1993-01-11 |
Family Cites Families (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS4955096U (en) * | 1972-08-23 | 1974-05-15 | ||
| IE43146B1 (en) * | 1975-07-22 | 1980-12-31 | Cpc International Inc | Starch based corrugating adhesives and methods for their preparation |
| JPS58747A (en) * | 1981-06-26 | 1983-01-05 | Fuji Electric Co Ltd | Oxygen sensor |
| JPS58148946A (en) * | 1982-02-27 | 1983-09-05 | Nissan Motor Co Ltd | Detector for air fuel ratio |
| JPS5994051A (en) * | 1982-11-19 | 1984-05-30 | Sogo Jidosha Anzen Kogai Gijutsu Kenkyu Kumiai | Oxygen sensor |
| JPS59190646A (en) * | 1983-04-12 | 1984-10-29 | Mitsubishi Electric Corp | Rich-burn sensor |
-
1984
- 1984-04-11 JP JP59072238A patent/JPS60216251A/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| JPS60216251A (en) | 1985-10-29 |
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