JPH09269313A - Method for measuring concentration of steam by limit current type gas sensor and apparatus therefor - Google Patents
Method for measuring concentration of steam by limit current type gas sensor and apparatus thereforInfo
- Publication number
- JPH09269313A JPH09269313A JP8103190A JP10319096A JPH09269313A JP H09269313 A JPH09269313 A JP H09269313A JP 8103190 A JP8103190 A JP 8103190A JP 10319096 A JP10319096 A JP 10319096A JP H09269313 A JPH09269313 A JP H09269313A
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- Prior art keywords
- water vapor
- sensor
- vapor concentration
- concentration
- output signal
- Prior art date
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- Measuring Oxygen Concentration In Cells (AREA)
Abstract
Description
【０００１】[0001]
【発明の属する技術分野】本発明は、固体電解質を用い
て、その内部を移動するイオンに基づく限界電流値から
水蒸気濃度を検出する限界電流式ガスセンサによる水蒸
気濃度測定方法及びそれを用いた測定装置に属する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for measuring water vapor concentration by a limiting current type gas sensor which detects a water vapor concentration from a limiting current value based on ions moving inside a solid electrolyte, and a measuring apparatus using the same. Belong to.
【０００２】[0002]
【従来の技術】従来より、図９に示すように、ジルコニ
ア等の固体電解質基板３０の表面に陰陽一対の電極３
１，３２を設けるとともに、外気から陰極３２に通じる
気体流入口を微小な孔３３とし、陰極３２に向かう気体
拡散を制限することにより、その制限された気体が陰極
３２表面でイオン化されて固体電解質基板３０内部を移
動する際に生じる限界電流値から、ガス濃度を検出する
センサ（以下、「限界電流式ガスセンサ」という。）が
知られている。2. Description of the Related Art Conventionally, as shown in FIG. 9, a pair of negative and positive electrodes 3 are formed on the surface of a solid electrolyte substrate 30 such as zirconia.
1 and 32 are provided, and the gas inlet port communicating from the outside air to the cathode 32 is made into a minute hole 33 to limit the gas diffusion toward the cathode 32, so that the limited gas is ionized on the surface of the cathode 32 and the solid electrolyte is formed. A sensor (hereinafter, referred to as “limit current type gas sensor”) that detects a gas concentration based on a limit current value generated when the substrate 30 moves inside is known.
【０００３】この限界電流式ガスセンサは、ガス濃度に
応じて正勾配をもって線形的に変化する限界電流を出力
する。従って、水蒸気センサとして利用する場合、既知
の水蒸気濃度とその限界電流値との対応関係を予め把握
しておけば、センサを測定雰囲気においたときの限界電
流値から水蒸気濃度を検出して濃度表示装置に表示する
ことができる。This limiting current type gas sensor outputs a limiting current that linearly changes with a positive gradient according to the gas concentration. Therefore, when used as a water vapor sensor, if the correspondence between the known water vapor concentration and its limiting current value is known in advance, the water vapor concentration is detected from the limiting current value when the sensor is placed in the measurement atmosphere and the concentration is displayed. Can be displayed on the device.
【０００４】ところが、限界電流式ガスセンサを用いた
検出装置において、測定雰囲気によっては長期間使用す
ると、センサの劣化により印加電圧に対する出力が低下
して測定誤差を生じる。すなわち、測定ガスが水蒸気で
あるときは、同一水蒸気濃度に対して限界電流値が低下
することとなり、実際の水蒸気濃度よりも低濃度を表示
する。However, in a detector using the limiting current type gas sensor, if it is used for a long time depending on the measurement atmosphere, the output with respect to the applied voltage is lowered due to the deterioration of the sensor, resulting in a measurement error. That is, when the measurement gas is water vapor, the limiting current value decreases for the same water vapor concentration, and a concentration lower than the actual water vapor concentration is displayed.
【０００５】このように劣化したセンサの出力を補正す
る従来の方法は、次のようなものである。(1)センサを
湿度発生槽等の既知の水蒸気濃度の雰囲気に入れて出力
を補正する。(2)同じ限界電流式ガスセンサを用いて酸
素濃度を測定するときも、同一酸素濃度に対して限界電
流値が低下していることから、表示酸素濃度が大気中の
酸素濃度である２０．８％となるようにアンプの可変抵
抗等を調整することにより出力を補正する（特開平６−
３１７５５９号段落番号００１９）。A conventional method for correcting the output of the sensor thus deteriorated is as follows. (1) Put the sensor in an atmosphere of known water vapor concentration such as a humidity generation tank to correct the output. (2) Even when measuring the oxygen concentration using the same limiting current type gas sensor, the limiting oxygen value decreases for the same oxygen concentration, so the displayed oxygen concentration is 20.8 in the atmosphere. The output is corrected by adjusting the variable resistance of the amplifier so that the ratio becomes% (Japanese Patent Laid-Open No. 6-
317559, paragraph number 0019).
【０００６】[0006]
【発明が解決しようとする課題】しかし、上記(1)の補
正方法では、湿度発生槽等の大がかりな装置が必要であ
るから、センサの取り付け場所で補正することができな
い。また、上記(2)の方法では、濃度対限界電流値の線
形関係を平行移動させることはできるが、勾配を補正す
ることはできない。However, in the correction method of the above (1), since a large-scale device such as a humidity generation tank is required, the correction cannot be performed at the sensor mounting location. Further, in the above method (2), the linear relationship between the concentration and the limiting current value can be translated, but the slope cannot be corrected.
【０００７】それ故、この発明の第１の目的は、限界電
流式ガスセンサを用いて、連続して正確に水蒸気濃度を
測定できる方法とその方法を利用した簡易な測定装置と
を提供することにある。第２の目的は、センサを特性の
異なる別のものと交換した場合でも、センサ取り付け場
所で短時間で出力を補正し継続して水蒸気濃度を測定で
きる方法とその方法を利用した水蒸気濃度測定装置を提
供することにある。Therefore, a first object of the present invention is to provide a method capable of continuously and accurately measuring the water vapor concentration using a limiting current type gas sensor, and a simple measuring apparatus using the method. is there. A second object is a method for correcting the output in a short time and continuously measuring the water vapor concentration at the place where the sensor is attached, and a water vapor concentration measuring apparatus using the method even when the sensor is replaced with another one having different characteristics. To provide.
【０００８】[0008]
【課題を解決するための手段】上記目的を達成するため
に、この発明の限界電流式ガスセンサによる水蒸気濃度
測定方法は、酸素イオン伝導性の固体電解質基板、それ
に密着した陰陽一対の電極及び陰極への気体拡散を制限
する気体拡散制限手段を有するセンサを用い、それら電
極間に直流電圧を印加したときの出力信号に基づいて水
蒸気濃度を測定する方法において、該センサが一定の酸
素濃度ＰOに応じて示す酸素濃度出力信号ＳL1とその後
にセンサが同一酸素濃度ＰOに応じて示す酸素濃度出力
信号ＳL1’との比ＳL1／ＳL1’を求めてそれを酸素濃度
補正係数ｋとし、センサが水蒸気濃度ＰHに応じて示す
水蒸気濃度出力信号ＳL2’に酸素濃度補正係数ｋを乗じ
て補正信号ｋ＊ＳL2’を算出し、水蒸気濃度ＰHと劣化
前のセンサの水蒸気濃度出力信号ＳL2との対応関係ＰH
＝ｆ（ＳL2）［ｆ：関数記号］を参照して補正信号ｋ＊
ＳL2’から水蒸気濃度を演算することを特徴とする。In order to achieve the above object, a method for measuring water vapor concentration by a limiting current type gas sensor according to the present invention is applied to an oxygen ion conductive solid electrolyte substrate, a pair of positive and negative electrodes and a cathode in close contact therewith. using a sensor having a gas diffusion limiting means for limiting the gas diffusion, a method of measuring the water vapor concentration on the basis of the output signal when a DC voltage is applied between the electrodes, the sensor is response to the constant oxygen concentration PO oxygen concentration output signal then the sensor and S L1 is it seeking 'ratio S L1 / S L1 of the' oxygen concentration output signal S L1 and the oxygen concentration correction coefficient k shown in accordance with the same oxygen concentration P O indicating Te, The correction signal k * S L2 'is calculated by multiplying the water vapor concentration output signal S L2 ' shown according to the water vapor concentration P H by the oxygen concentration correction coefficient k, and the water vapor concentration P H and the water vapor concentration of the sensor before deterioration are calculated. Correspondence P H with output signal S L2
= F (S L2 ) [f: function symbol] and the correction signal k *
It is characterized in that the water vapor concentration is calculated from S L2 '.
【０００９】同じく、この発明の水蒸気濃度測定装置
は、酸素イオン伝導性の固体電解質基板、それに密着し
た陰陽一対の電極及び陰極への気体拡散を制限する気体
拡散制限手段を有するセンサと該センサが一定の酸素濃
度ＰOに応じて示す酸素濃度出力信号ＳL1とその後にセ
ンサが同一酸素濃度ＰOに応じて示す酸素濃度出力信号
ＳL1’との比ＳL1／ＳL1’を求めてそれを酸素濃度補正
係数ｋとし、センサが水蒸気濃度ＰHに応じて示す水蒸
気濃度出力信号ＳL2’に酸素濃度補正係数ｋを乗じて補
正信号ｋ＊ＳL2’を算出する出力補正演算手段と、水蒸
気濃度ＰHと劣化前のセンサの水蒸気濃度出力信号ＳL2
との対応関係ＰH＝ｆ（ＳL2）［ｆ：関数記号］を参照
して補正信号ｋ＊ＳL2’から水蒸気濃度を演算する出力
演算手段とを備えたことを特徴とする。Similarly, in the water vapor concentration measuring apparatus of the present invention, the oxygen ion conductive solid electrolyte substrate, a sensor having a pair of negative and positive electrodes and a gas diffusion limiting means for limiting gas diffusion to the cathode, and the sensor are provided. The ratio S L1 / S L1 'of the oxygen concentration output signal S L1 which shows according to the constant oxygen concentration P O and the oxygen concentration output signal S L1 ' which shows afterwards the sensor shows the same oxygen concentration P O is found and calculated. was the oxygen concentration correction coefficient k, and output correction calculation means sensor to calculate the 'corrected signal k * S L2 is multiplied by the oxygen concentration correction factor k' steam concentration output signal S L2 shown in accordance with the water vapor concentration P H, Water vapor concentration P H and water vapor concentration output signal S L2 of the sensor before deterioration
And the output calculation means for calculating the water vapor concentration from the correction signal k * S L2 'with reference to the correspondence P H = f (S L2 ) [f: function symbol].
【００１０】尚、酸素濃度補正係数ｋに代えて、該セン
サが一定の水蒸気濃度ＰHに応じて示す水蒸気濃度出力
信号ＳHとその後にセンサが同一水蒸気濃度ＰHに応じて
示す水蒸気濃度出力信号ＳH’との比ＳH／ＳH’を求め
てそれを補正係数ｋ（この場合は水蒸気濃度補正係数と
なる）とし、センサが水蒸気濃度ＰHに応じて示す水蒸
気濃度出力信号ＳL2’に水蒸気濃度補正係数ｋを乗じて
補正信号ｋ＊ＳL2’を算出してもよいが、水蒸気濃度の
補正の度に一定の水蒸気濃度を設定することはわずらわ
しいので、ｋを酸素濃度補正係数として求めるのが好ま
しい。In place of the oxygen concentration correction coefficient k, a water vapor concentration output signal S H which the sensor indicates in response to a constant water vapor concentration P H and a water vapor concentration output which the sensor subsequently indicates in response to the same water vapor concentration P H signal S seeking 'ratio S H / S H and' H to it with the correction coefficient k (this becomes water vapor concentration correction coefficient in this case), the water vapor concentration output signal S L2 indicating sensor in response to water vapor concentration P H The correction signal k * S L2 'may be calculated by multiplying' by the water vapor concentration correction coefficient k, but it is troublesome to set a constant water vapor concentration each time the water vapor concentration is corrected. Is preferably calculated as
【００１１】本発明者等は、限界電流式ガスセンサの印
加電圧対限界電流値特性において、図５に示すように、
酸素濃度に対し、第１の平坦部Ｆ１に現れる第１の拡散
制限電流値ＩL1と水蒸気濃度に対し、第２の平坦部Ｆ２
に現れる第２の拡散制限電流値ＩL2は、各センサ素子毎
にまたセンサ素子の劣化の程度に応じて異なるものであ
るが、ＩL1／ＩL2比は、同一酸素濃度下で同一温度では
センサあるいはその劣化の程度が異なっても一定であ
り、水蒸気濃度に応じてのみ変化するものであることを
見出し、前記ＩL1／ＩL2比に基づいて水蒸気濃度を求め
ることを提案した（特開平４−５０７６３号公報）。As shown in FIG. 5, the inventors of the present invention have shown the characteristics of applied voltage versus limiting current value of the limiting current type gas sensor as shown in FIG.
With respect to the oxygen concentration, the first diffusion limiting current value I L1 appearing in the first flat portion F1 and the second flat portion F2 with respect to the water vapor concentration.
The second diffusion limiting current value I L2 appearing in the above is different for each sensor element and according to the degree of deterioration of the sensor element, but the I L1 / I L2 ratio is the same at the same oxygen concentration and at the same temperature. It has been found that the sensor or the degree of deterioration thereof is constant even if it is different, and that it changes only in accordance with the water vapor concentration, and it has been proposed to obtain the water vapor concentration based on the I L1 / I L2 ratio (Japanese Patent Laid-Open No. Hei 10-1999) 4-50763).
【００１２】本発明は、ＩL1／ＩL2比が一定である原理
を利用して、さらに例えば大気中の酸素濃度が一定であ
ることを利用し、上記特徴を備えることにより水蒸気濃
度を長期的に正確に測定することを可能にする。すなわ
ち、ＩL1／ＩL2比が一定であるということは、センサの
交換あるいはセンサの劣化に伴って、第１の平坦部Ｆ１
に現れる拡散制限電流値及び第２の平坦部Ｆ２に現れる
拡散制限電流値がそれぞれＩL1’及びＩL2’に変化して
も、その比ＩL1’／ＩL2’は交換前又は劣化前のＩL1／
ＩL2比に等しい。式に表せばＩL1／ＩL2＝ＩL1’／
ＩL2’である。従ってＩL1／ＩL1’＝ＩL2／ＩL2’（＝
ｋ）も常に成り立つ。The present invention utilizes the principle that the I L1 / I L2 ratio is constant, and further utilizes, for example, that the oxygen concentration in the atmosphere is constant. Allows to measure accurately. That is, the fact that the I L1 / I L2 ratio is constant means that the first flat portion F1 is accompanied by the replacement of the sensor or the deterioration of the sensor.
Even if the diffusion limiting current value appearing in the above and the diffusion limiting current value appearing in the second flat portion F2 change to I L1 'and I L2 ', respectively, the ratio I L1 '/ I L2 ' I L1 /
It is equal to the I L2 ratio. Expressed in the formula, I L1 / I L2 = I L1 '/
I L2 '. Therefore, I L1 / I L1 '= I L2 / I L2 ' (=
k) always holds.
【００１３】さて、水蒸気濃度に応じた、劣化センサの
第２の拡散制限電流値ＩL2’を補正する場合、劣化する
前の第２の拡散制限電流値ＩL2を基準にして劣化後のＩ
L2’がどれだけ変化したかを比（α＝ＩL2’／ＩL2）で
求め、このαの逆数を補正係数（ｋ＝１／α）として用
いることもできるが、この補正方法は劣化前のＩL2を測
定したときと同じ測定雰囲気条件（同一水蒸気濃度、同
一温度及び同一酸素濃度）を必要とする。[0013] Now, according to the water vapor concentration, when correcting the second diffusion limit current value I L2 'degradation sensor, after degradation with respect to the second diffusion limit current value I L2 before degradation I
It is also possible to find how much L2 'changes with a ratio (α = I L2 ' / I L2 ) and use the reciprocal of this α as a correction coefficient (k = 1 / α). The same measurement atmosphere conditions (the same water vapor concentration, the same temperature, and the same oxygen concentration) as in the measurement of I L2 are required.
【００１４】一方、本発明においては、劣化センサのＩ
L2’を補正する場合、劣化前の第１の拡散制限電流値Ｉ
L1を基準にして劣化後の第１の拡散制限電流値ＩL1’が
この基準に対してどれだけ変化したかを比（ＩL1’／Ｉ
L1＝１／ｋ）で求め、このｋを補正係数に用いて劣化後
の第２の拡散制限電流値ＩL2’又はＩL2’に関連する水
蒸気濃度（後述のＳL2’）等のデータを補正するもので
あり、有利な点は上述の方法に比べて、同一の水蒸気濃
度を必要としないことにある。On the other hand, in the present invention, the deterioration sensor I
When correcting L2 ', the first diffusion limit current value I before deterioration is
The ratio (I L1 '/ I) of how much the first diffusion limiting current value I L1 ' after deterioration with respect to L1 has changed with respect to this standard.
L1 = 1 / k), and using this k as a correction coefficient, data such as water vapor concentration (S L2 'described later) related to the second diffusion limiting current value I L2 ' or I L2 'after deterioration is obtained. It is a correction and the advantage is that it does not require the same water vapor concentration compared to the method described above.
【００１５】つまり、ＩL1は、水蒸気濃度に対して独立
したパラメータであり、大気中の酸素濃度が２０．８％
と一定であることから、それを基準として水蒸気濃度を
容易且つ確実に補正することができる。That is, I L1 is a parameter independent of the water vapor concentration, and the oxygen concentration in the atmosphere is 20.8%.
Since it is constant, the water vapor concentration can be easily and surely corrected with reference to it.
【００１６】そこで、劣化前のセンサが例えば大気中の
ように既知の酸素濃度ＰOに応じて示す第１の拡散制限
電流値ＩL1と、その後に交換され又は経時的に劣化した
センサが同一酸素濃度ＰOに応じて示す第１の拡散制限
電流値ＩL1’との比ＩL1／ＩL1’を求めてそれを酸素濃
度補正係数ｋとする。ここで、酸素濃度補正係数ｋは、
比であって、各々の拡散制限電流値の絶対値を求めるこ
とは重要ではない。従って、拡散制限電流値の比に限ら
ず、拡散制限電流値を増幅した値の比であっても良い
し、電圧信号やデジタル信号に変換した値の比であって
も良い。よって、ｋを酸素濃度出力信号の比ＳL1／
ＳL1’とする。Therefore, the first diffusion limiting current value I L1 which the sensor before deterioration shows according to a known oxygen concentration P O , such as in the atmosphere, and the sensor which has been replaced or deteriorated with time are the same. The ratio I L1 / I L1 'with the first diffusion limiting current value I L1 ' shown according to the oxygen concentration P O is obtained, and this is used as the oxygen concentration correction coefficient k. Here, the oxygen concentration correction coefficient k is
It is a ratio, and it is not important to obtain the absolute value of each diffusion limiting current value. Therefore, the ratio is not limited to the ratio of the diffusion limiting current value, and may be the ratio of the amplified value of the diffusion limiting current value or the ratio of the values converted into the voltage signal or the digital signal. Therefore, k is the ratio of the oxygen concentration output signal S L1 /
S L1 '
【００１７】そして、交換され又は経時劣化したセンサ
が水蒸気濃度ＰHに応じて示す水蒸気濃度出力信号
ＳL2’に酸素濃度補正係数ｋを乗じて補正信号ｋ＊
ＳL2’を算出する。ここでも水蒸気濃度出力信号ＳL2’
及び後述の水蒸気濃度出力信号ＳL2は、第２の拡散制限
電流値、その増幅値、電圧値及びそれらのデジタル化値
のいずれでもよい。次に、水蒸気濃度ＰHと初期のセン
サの水蒸気濃度出力信号ＳL2との対応関係ＰH＝ｆ（Ｓ
L2）［ｆ：関数記号］を参照する。既述の通りＩL1／Ｉ
L2＝ＳL1／ＳL2＝一定であるから、ＳL2／ＳL2’＝α＝
ｋすなわちＳL2＝ｋ＊ＳL2’となり、補正信号ｋ＊
ＳL2’に基づいて水蒸気濃度を演算することができる。
従って、予めＰH＝ｆ（ＳL2）を求めておけば、センサ
が交換され又は劣化して出力がＳL2からＳL2’に変化し
ても、ＳL2を出力している初期状態と同じ水蒸気濃度が
表示される。Then, the sensor, which has been replaced or deteriorated with time, multiplies the water vapor concentration output signal S L2 'shown according to the water vapor concentration P H by the oxygen concentration correction coefficient k to obtain a correction signal k *.
Calculate S L2 '. Again, the water vapor concentration output signal S L2 '
Further, the water vapor concentration output signal S L2 described later may be any of the second diffusion limiting current value, its amplification value, voltage value and their digitized value. Next, the correspondence relationship between the water vapor concentration P H and the initial sensor water vapor concentration output signal S L2 P H = f (S
L2 ) Refer to [f: Function symbol]. As mentioned above, I L1 / I
Since L2 = S L1 / S L2 = constant, S L2 / S L2 '= α =
k, that is, S L2 = k * S L2 ', and the correction signal k *
The water vapor concentration can be calculated based on S L2 '.
Therefore, in advance if seeking P H = f (S L2) , even if the output sensor is replaced or deteriorated is changed to S L2 'from S L2, the same as the initial state of outputting S L2 The water vapor concentration is displayed.
【００１８】[0018]
【発明の実施の形態】出力補正演算手段及び出力演算手
段は、通常マイコン内にデジタル回路として組まれる
が、アナログ回路でも良い。マイコン内に組むときは、
マイコンの入力側にＡ／Ｄコンバータ、出力側にＤ／Ａ
コンバータを接続する。センサからの出力信号として電
圧信号を用いるときは、センサから出力される電流信号
をプリアンプにて増幅し、電圧信号に変換する。BEST MODE FOR CARRYING OUT THE INVENTION The output correction calculating means and the output calculating means are usually incorporated in a microcomputer as a digital circuit, but may be an analog circuit. When assembled in a microcomputer,
A / D converter on the input side of the microcomputer, D / A on the output side
Connect the converter. When the voltage signal is used as the output signal from the sensor, the current signal output from the sensor is amplified by the preamplifier and converted into the voltage signal.
【００１９】センサは経時的に劣化するから、劣化後の
酸素濃度出力信号ＳL1’及び水蒸気濃度出力信号ＳL2’
も時間とともに変化する。従って、センサには水蒸気濃
度測定用電圧Ｖａ及び酸素濃度測定用電圧Ｖｂのいずれ
かが自在に印加されるようにしておくとともに、センサ
作動スイッチとは別個に出力補正スタートスイッチを設
け、出力補正スタートスイッチをＯＮする度に酸素濃度
測定電圧に基づいて酸素濃度の出力補正を行う出力補正
演算手段により酸素濃度補正係数ｋを更新するようにし
ておくと好ましい。こうすることで、理論的には永久に
正確な水蒸気濃度を測定することができる。また、出力
補正スタートスイッチが測定装置の作動時に自動的に作
動するように回路を構成しても良い。Since the sensor deteriorates with time, the oxygen concentration output signal S L1 'and the water vapor concentration output signal S L2 ' after the deterioration.
Also changes over time. Therefore, either the water vapor concentration measurement voltage Va or the oxygen concentration measurement voltage Vb is freely applied to the sensor, and an output correction start switch is provided separately from the sensor operation switch to start the output correction start. It is preferable that the oxygen concentration correction coefficient k be updated by the output correction calculation means that performs output correction of the oxygen concentration based on the oxygen concentration measurement voltage each time the switch is turned on. By doing so, theoretically, it is possible to permanently and accurately measure the water vapor concentration. Further, the circuit may be configured so that the output correction start switch automatically operates when the measuring device operates.
【００２０】[0020]
【実施例】この発明の限界電流式ガスセンサ（以下、単
に「センサ」という。）による水蒸気濃度測定方法及び
水蒸気濃度測定装置の実施例を図面とともに説明する。
図１は、実施例に係わる限界電流式ガスセンサを示す斜
視図、図２は、図１のＡＡ断面図、図３は、図２の変形
例を示す断面図、図４は、図１のセンサの下部に固着さ
れるセラミックヒータを示す一部破断斜視図である。DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a method for measuring water vapor concentration and a water vapor concentration measuring apparatus using a limiting current type gas sensor (hereinafter, simply referred to as "sensor") of the present invention will be described with reference to the drawings.
1 is a perspective view showing a limiting current type gas sensor according to an embodiment, FIG. 2 is a sectional view taken along the line AA of FIG. 1, FIG. 3 is a sectional view showing a modification of FIG. 2, and FIG. 4 is a sensor shown in FIG. FIG. 3 is a partially cutaway perspective view showing a ceramic heater fixed to the lower part of FIG.
【００２１】センサ１は、板状のセラミックヒータ２０
とその主面に一体的に設けられる酸素イオン伝導性を示
す固体電解質板である安定化ジルコニア板１０とこの安
定化ジルコニア板１０中に並べられて埋設される陽電極
３、陰電極２及びガス出口孔８とを備える。The sensor 1 comprises a plate-shaped ceramic heater 20.
And a stabilized zirconia plate 10 that is a solid electrolyte plate that is integrally provided on the main surface thereof and exhibits oxygen ion conductivity, and a positive electrode 3, a negative electrode 2 and a gas that are arranged and embedded in the stabilized zirconia plate 10. And an outlet hole 8.
【００２２】安定化ジルコニア板１０は酸化ジルコニウ
ムに安定化剤として酸化イットリウムを添加固溶させた
固体電解質であり、本実施例では厚さ０．３ｍｍ、縦５
ｍｍ、横２３ｍｍの大きさで、厚さ方向に貫通した通気
口９が中央に設けられている。なお、セラミックヒータ
２０と安定化ジルコニア板１０とは、ガス出口孔８を除
く他は平面視同一形状で、通気口９に整合する通気口１
５がセラミックヒータ２０にも設けられている。The stabilized zirconia plate 10 is a solid electrolyte in which yttrium oxide as a stabilizer is added to zirconium oxide to form a solid solution. In this embodiment, the thickness is 0.3 mm and the length is 5 mm.
The vent hole 9 has a size of 23 mm and a width of 23 mm and penetrates in the thickness direction at the center. The ceramic heater 20 and the stabilized zirconia plate 10 have the same shape in plan view except for the gas outlet hole 8 and are aligned with the ventilation hole 9 in the ventilation hole 1.
5 is also provided in the ceramic heater 20.
【００２３】陽電極３、陰電極２は多孔質の白金層（厚
さ数十μｍ）であり、一辺約２ｍｍの電極部３ａ，２
ａ、長寸のリード部３ｂ，２ｂ及び取り出し部３ｃ，２
ｃからなる。リード部２ｂは、その中間で白金層が分岐
して安定化ジルコニア板１０の側面に導出しており、ガ
ス導入部６を形成している。そして、リード部２ｂのう
ち、このガス導入部６から陰電極部２ａに至るまでの長
さ分がガス拡散制限部７となる。The positive electrode 3 and the negative electrode 2 are porous platinum layers (thickness: several tens of μm), and the electrode portions 3a, 2 each having a side of about 2 mm.
a, long lead portions 3b, 2b and take-out portions 3c, 2
It consists of c. In the lead portion 2b, a platinum layer branches in the middle and leads to the side surface of the stabilized zirconia plate 10, and forms a gas introduction portion 6. The length of the lead portion 2b from the gas introducing portion 6 to the negative electrode portion 2a becomes the gas diffusion limiting portion 7.
【００２４】ガス出口孔８は、陽電極部３ａの位置に対
応して安定化ジルコニア板１０に設けられた孔であり、
陽電極部３ａと外部とを連通する。なお、ガス出口孔８
は陽電極部３ａと外部とが通じていればどんな形状、大
きさであっても良い。次に、センサ１の製造方法を述べ
る。The gas outlet hole 8 is a hole provided in the stabilized zirconia plate 10 corresponding to the position of the positive electrode portion 3a,
The positive electrode portion 3a communicates with the outside. The gas outlet hole 8
May have any shape and size as long as the positive electrode portion 3a communicates with the outside. Next, a method for manufacturing the sensor 1 will be described.
【００２５】セラミックヒータ２０は、焼成後に通気口
１５となる孔を打ち抜いた無機成分中のアルミナ含有率
が９６重量％のグリーンシートの上面に白金ペーストで
ヒータパターン１２を印刷し、端部に白金端子１３，１
４をのせた後、同質のアルミナグリーンシートを被せ、
これを焼成一体化して製造される（図４）。In the ceramic heater 20, the heater pattern 12 is printed with a platinum paste on the upper surface of a green sheet having a content of alumina in the inorganic component of 96% by weight punched out to form the vent hole 15 after firing, and the end portion of the heater is covered with platinum. Terminals 13, 1
After placing 4, put the same quality alumina green sheet,
It is manufactured by firing and integrating this (FIG. 4).
【００２６】一方、焼成後に通気口９となる孔をあけた
ジルコニア９２モル％及びイットリア８モル％の固体電
解質を含むグリーンシート上に、焼成後に陽電極３、陰
電極２となるように白金ペーストを印刷し、端部に白金
端子４，５をのせた後、同質のグリーンシートを積層
し、約１５００℃で一体焼成することにより、安定化ジ
ルコニア板１０、陰陽電極２，３及び白金端子４，５か
らなるセンサ素子を製造する。２枚のグリーンシート
は、断面を観察しても図２のように一体化して見分けが
つかなくなる。On the other hand, on the green sheet containing 92 mol% of zirconia and 8 mol% of yttria solid electrolyte, which was perforated to form the vent holes 9 after firing, the platinum paste so that the positive electrode 3 and the negative electrode 2 were formed after firing. Is printed, and the platinum terminals 4 and 5 are placed on the ends, and then the same quality green sheets are laminated and integrally fired at about 1500 ° C. to obtain the stabilized zirconia plate 10, the positive and negative electrodes 2 and 3, and the platinum terminals 4. , 5 is manufactured. The two green sheets are integrated and become indistinguishable as shown in FIG. 2 even when the cross section is observed.
【００２７】なお、白金ペーストの印刷されるグリーン
シートは、酸素イオン伝導性固体電解質を主成分とする
ことが必要であるが、その上に積層されるグリーンシー
トは、それに限らず、例えばアルミナを主成分とするも
ののように同様に密封でき焼成できるものであれば良
い。その場合は、断面を観察すると、図３のように両シ
ートの境界線が残る。The green sheet on which the platinum paste is printed needs to contain an oxygen ion conductive solid electrolyte as a main component, but the green sheet laminated thereon is not limited to this, and for example, alumina may be used. Any material that can be similarly sealed and fired, such as the one containing the main component, may be used. In that case, when the cross section is observed, the boundary line between both sheets remains as shown in FIG.
【００２８】センサ素子は、封着ガラス等を用いてセラ
ミックヒータ２０の表面に約８００℃で固着されセンサ
１となる。次にセンサ１の動作を説明する。The sensor element is fixed to the surface of the ceramic heater 20 at about 800 ° C. using sealing glass or the like to form the sensor 1. Next, the operation of the sensor 1 will be described.
【００２９】センサ１を測定ガス中に配置し、各電極部
２ａ，３ａが局所的に約５００℃となるようにセラミッ
クヒータ２０に通電した後、陽電極３と陰電極２の間に
電圧を印加する。すると、陰電極２の陰電極部２ａ内部
の酸素は、イオン化されて酸素イオンとなり、印加電圧
Ｖに応じて陰電極２から陽電極３に輸送される。この
時、安定化ジルコニア板１０のうち陰電極部２ａに隣接
する部分のみが局所的に加熱され、ガス拡散制限部７に
隣接する部分は酸素イオン伝導性を示す程充分に加熱さ
れていないため、ガス導入部６から導入された酸素は安
定化ジルコニア板１０内を伝導することなくガス拡散制
限部７を通って陰電極部２ａ内に拡散する。そして、各
電極部２ａ，３ａの付近のジルコニアは前記の通り充分
に加熱されているので、酸素イオン伝導性を示し、ガス
導入部６から陰電極部２ａに拡散してきた酸素成分をイ
オン化して電極部３ａに輸送し、ガス出口孔８より排出
する。従って、陽電極３−陰電極２間に流れる電流Ｉ
は、図５に示すように変化する。After the sensor 1 is placed in the measurement gas and the ceramic heater 20 is energized so that the respective electrode portions 2a, 3a are locally heated to about 500 ° C., a voltage is applied between the positive electrode 3 and the negative electrode 2. Apply. Then, oxygen inside the negative electrode portion 2a of the negative electrode 2 is ionized into oxygen ions, which are transported from the negative electrode 2 to the positive electrode 3 according to the applied voltage V. At this time, only the portion of the stabilized zirconia plate 10 adjacent to the negative electrode portion 2a is locally heated, and the portion adjacent to the gas diffusion limiting portion 7 is not sufficiently heated to exhibit oxygen ion conductivity. The oxygen introduced from the gas introduction part 6 diffuses into the negative electrode part 2a through the gas diffusion limiting part 7 without conducting in the stabilized zirconia plate 10. Since the zirconia near the electrode portions 2a and 3a is sufficiently heated as described above, it exhibits oxygen ion conductivity and ionizes the oxygen component diffused from the gas introduction portion 6 to the negative electrode portion 2a. It is transported to the electrode portion 3a and discharged from the gas outlet hole 8. Therefore, the current I flowing between the positive electrode 3 and the negative electrode 2
Changes as shown in FIG.
【００３０】印加電圧ＶがＶ１より低いときは印加電圧
Ｖに応じて酸素イオンが伝導するので、電流値もそれに
比例して変化するが、印加電圧Ｖが電圧値Ｖ１〜Ｖ２に
おいては、陰電極部２ａ内への酸素拡散量が陰電極２の
ガス拡散制限部７で制御され、測定ガス中の酸素濃度に
応じた値となるため、それに伴い電流値は制限されて第
１の拡散制限電流値ＩL1となり第１の平坦部Ｆ１として
現れる。印加電圧Ｖが第１の拡散制限電流値ＩL1が得ら
れる電圧値Ｖ２（通常１．２Ｖ）よりさらに高くなる
と、測定ガス中の水蒸気が電気分解され、その分解で生
じた酸素イオンがさらに増加し陽電極３にポンピングさ
れるため、水蒸気も陰電極２のガス導入部６から陰電極
部２ａ内へ拡散し、拡散量に応じて電流値が増大する。When the applied voltage V is lower than V1, oxygen ions conduct according to the applied voltage V, so the current value changes in proportion to it, but when the applied voltage V is the voltage values V1 to V2, the negative electrode is used. The oxygen diffusion amount into the portion 2a is controlled by the gas diffusion limiting portion 7 of the negative electrode 2 and has a value according to the oxygen concentration in the measurement gas, so the current value is limited accordingly and the first diffusion limiting current is reduced. The value becomes I L1 and appears as the first flat portion F1. When the applied voltage V becomes higher than the voltage value V2 (normally 1.2 V) at which the first diffusion limiting current value I L1 is obtained, the water vapor in the measurement gas is electrolyzed and the oxygen ions generated by the decomposition further increase. Since the positive electrode 3 is pumped, the water vapor also diffuses from the gas introduction portion 6 of the negative electrode 2 into the negative electrode portion 2a, and the current value increases in accordance with the amount of diffusion.
【００３１】印加電圧Ｖをさらに高くすると電流値は水
蒸気濃度に応じてさらに増大するが、電圧値Ｖ３〜Ｖ４
に達すると、陰電極２のガス拡散制限部７で水蒸気の拡
散量が制限され、それに伴い電流値も制限され、測定ガ
ス中の水蒸気濃度に応じた第２の拡散制限電流値ＩL2と
なり第２の平坦部Ｆ２を示す。ＩL1／ＩL2比は、測定ガ
スの成分の量が同じであれば原理的に常に一定である。When the applied voltage V is further increased, the current value further increases according to the water vapor concentration, but the voltage values V3 to V4.
When the temperature reaches, the diffusion amount of water vapor is limited by the gas diffusion limiting portion 7 of the negative electrode 2, and the current value is also limited accordingly, and the second diffusion limiting current value I L2 corresponding to the water vapor concentration in the measurement gas is obtained. 2 shows a flat portion F2. In principle, the I L1 / I L2 ratio is always constant if the amounts of the components of the measurement gas are the same.
【００３２】この第２の拡散制限電流値ＩL2は酸素濃度
一定の場合（例えば大気中）、水蒸気濃度に応じて図６
のように右上がりに線形的に変化する。従って、第２の
拡散制限電流値ＩL2又はそれと比例関係にある出力電圧
を検出信号として取り出すことにより、水蒸気濃度を測
定することができる。When the oxygen concentration is constant (for example, in the atmosphere), the second diffusion limiting current value I L2 depends on the water vapor concentration.
It changes linearly to the right as in. Therefore, the water vapor concentration can be measured by taking out the second diffusion limiting current value I L2 or the output voltage proportional to it as the detection signal.
【００３３】このセンサを用いて図７のような回路構成
の検出装置で出力を取り出すようにする。検出装置は、
センサ１と、センサ１の電極２，３間に印加する電圧を
通常計測時に用いる水蒸気濃度測定用電圧Ｖa（約２．
０Ｖ）又は出力補正時に用いる酸素濃度測定用電圧Ｖb
（約１．０Ｖ）に切り換えるセンサ電圧切り換え回路７
１と、センサ１から出力される電流信号を増幅し電圧信
号に変換するプリアンプ７２と、その電圧信号をデジタ
ル化するＡ／Ｄコンバータと、デジタル化された信号を
演算するマイコン７３と、マイコン７３から出されたデ
ータをアナログ化するＤ／Ａコンバータと、アナログ化
された信号を水蒸気濃度表示部７４に送る出力回路７５
と、水蒸気濃度表示部７４を備える。Using this sensor, an output is taken out by a detection device having a circuit configuration as shown in FIG. The detection device is
The voltage applied between the sensor 1 and the electrodes 2 and 3 of the sensor 1 is a vapor concentration measuring voltage Va (about 2.
0V) or the oxygen concentration measurement voltage Vb used for output correction
Sensor voltage switching circuit 7 for switching to (about 1.0 V)
1, a preamplifier 72 that amplifies a current signal output from the sensor 1 and converts it into a voltage signal, an A / D converter that digitizes the voltage signal, a microcomputer 73 that calculates the digitized signal, and a microcomputer 73. D / A converter for analogizing the data output from the device, and an output circuit 75 for sending an analog signal to the water vapor concentration display unit 74.
And a water vapor concentration display unit 74.
【００３４】マイコン７３は、ＣＰＵと、主として出力
演算部及び出力補正演算部の２つのプログラムが格納さ
れたＲＯＭ、ＲＡＭ等のメモリーとからなる。出力演算
部には、予め水蒸気濃度ＰHと製造直後のセンサ１から
水蒸気濃度に応じてプリアンプ７２及びＡ／Ｄコンバー
タを通して入力された水蒸気濃度出力信号ＳL2との対応
関係ＰH＝ｆ（ＳL2）が記憶されており、その後に水蒸
気濃度に応じて入力される水蒸気濃度出力信号ＳL2’を
ＰH＝ｆ（ＳL2）のＳL2に代入して水蒸気濃度ＰHを演算
できるようになっている。The microcomputer 73 is composed of a CPU and a memory such as a ROM and a RAM which mainly stores two programs of an output calculation unit and an output correction calculation unit. The output calculation unit, advance correspondence relationship from the sensor 1 immediately after production and steam concentration P H and steam concentration output signal S L2 inputted through the preamplifier 72 and the A / D converter in accordance with the water vapor concentration P H = f (S L2 ) is stored, and the water vapor concentration output signal S L2 'which is subsequently input according to the water vapor concentration is substituted into S L2 of P H = f (S L2 ) so that the water vapor concentration P H can be calculated. Has become.
【００３５】また、出力補正演算部には予め、製造直後
のセンサ１から酸素濃度ＰOに応じてプリアンプ７２及
びＡ／Ｄコンバータを通して入力された酸素濃度出力信
号の初期値ＳL1が記憶されており、その後に出力補正ス
タートスイッチＯＮの状態で同一酸素濃度ＰOに応じて
酸素濃度出力信号ＳL1’が入力されたとき、（ＳL1／Ｓ
L1’）＝ｋを算出し、さらに上記水蒸気濃度出力信号Ｓ
L2’に酸素濃度補正係数ｋを乗じて補正信号ｋ＊ＳL2’
を算出できるようになっている。そして、酸素濃度補正
係数ｋが算出されたときは、それ以後にマイコンに入力
される水蒸気濃度出力信号ＳL2’は、一旦出力補正演算
部で常に補正信号ｋ＊ＳL2’に補正されてから出力演算
部に戻り、補正信号ｋ＊ＳL2’から水蒸気濃度が演算さ
れる。ただし、酸素濃度補正係数ｋを算出するプログラ
ムは、出力補正スタートスイッチをＯＮする度に実行さ
れ、酸素濃度補正係数ｋが更新される。なお、出荷時は
ｋ＝１に設定されている。Further, the output correction calculation unit stores in advance the initial value S L1 of the oxygen concentration output signal which is input from the sensor 1 immediately after manufacture through the preamplifier 72 and the A / D converter in accordance with the oxygen concentration P O. Then, when the oxygen concentration output signal S L1 'is input according to the same oxygen concentration P O while the output correction start switch is ON, (S L1 / S
L1 ') = k is calculated, and the above water vapor concentration output signal S is calculated.
The correction signal k * S L2 'is obtained by multiplying L2 ' by the oxygen concentration correction coefficient k.
Can be calculated. When the oxygen concentration correction coefficient k is calculated, the water vapor concentration output signal S L2 'after that is input to the microcomputer after being always corrected to the correction signal k * S L2 ' by the output correction calculation unit. Returning to the output calculation unit, the water vapor concentration is calculated from the correction signal k * S L2 '. However, the program for calculating the oxygen concentration correction coefficient k is executed every time the output correction start switch is turned on, and the oxygen concentration correction coefficient k is updated. Note that k = 1 is set at the time of shipment.
【００３６】センサ印加電圧Ｖは、通常測定時には水蒸
気濃度に応じた拡散制限電流値ＩL2の得られるＶａ（＝
Ｖ３〜Ｖ４）に設定される。すると、この拡散制限電流
値ＩL2は、プリアンプ７２にて増幅され電圧信号に変換
され、続いてＡ／Ｄコンバータにてデジタル化されて水
蒸気濃度出力信号ＳL2としてマイコン７３に送られる。
マイコン７３内では入力された水蒸気濃度出力信号ＳL2
を対応関係ＰH＝ｆ（ＳL2）と照合して水蒸気濃度を演
算し、出力する。その出力データはＤ／Ａコンバータに
てアナログ化され、出力回路７５にて水蒸気濃度表示部
７４に送られる。次に上記の水蒸気濃度測定装置におい
てセンサ１が劣化した場合に水蒸気濃度出力を補正する
方法を説明する。The sensor applied voltage V is Va (=) at which the diffusion limiting current value I L2 corresponding to the water vapor concentration can be obtained during normal measurement.
V3 to V4). Then, the diffusion limiting current value I L2 is amplified by the preamplifier 72, converted into a voltage signal, then digitized by the A / D converter, and sent to the microcomputer 73 as a water vapor concentration output signal S L2 .
In the microcomputer 73, the input water vapor concentration output signal S L2
Is compared with the correspondence P H = f (S L2 ) to calculate and output the water vapor concentration. The output data is analogized by the D / A converter and sent to the water vapor concentration display section 74 by the output circuit 75. Next, a method of correcting the water vapor concentration output when the sensor 1 deteriorates in the above water vapor concentration measuring device will be described.
【００３７】先ず、センサ１が劣化する前の初期状態す
なわち製造直後の状態でセンサ印加電圧Ｖを酸素濃度に
応じた第１の拡散制限電流値ＩL1の得られるＶｂ（＝Ｖ
１〜Ｖ２）に設定したとき、濃度表示部が測定ガス中の
酸素濃度（大気中の場合２０．８％）を表示するように
調整しておく。ここで、センサ１の劣化によって、同一
酸素濃度に応じて出力する第１拡散制限電流がＩL1から
ＩL1’に変化したとする（図８(a)）。そのとき、前記
の同一酸素濃度の雰囲気（例えば大気）にセンサ１を配
置し、出力補正スタートスイッチをＯＮにする。センサ
印加電圧はＶａからＶｂに切り替わり、ＩL1’に対応し
た酸素濃度出力信号ＳL1’がマイコン７３に入力され
る。この信号ＳL1’と初期にマイコン７３に記憶されて
いた酸素濃度出力信号ＳL1を基に酸素濃度補正係数ｋが
更新され、マイコン７３に記憶される。First, in the initial state before the sensor 1 deteriorates, that is, in the state immediately after manufacturing, the sensor applied voltage V is Vb (= V) at which the first diffusion limiting current value I L1 corresponding to the oxygen concentration is obtained.
1 to V2), the concentration display unit is adjusted so as to display the oxygen concentration in the measurement gas (20.8% in the atmosphere). Here, it is assumed that the first diffusion limiting current output according to the same oxygen concentration changes from IL1 to IL1 'due to deterioration of the sensor 1 (FIG. 8 (a)). At that time, the sensor 1 is arranged in the atmosphere having the same oxygen concentration (for example, the atmosphere), and the output correction start switch is turned on. The sensor applied voltage is switched from Va to Vb, and the oxygen concentration output signal S L1 'corresponding to I L1 ' is input to the microcomputer 73. The oxygen concentration correction coefficient k is updated based on this signal S L1 ′ and the oxygen concentration output signal S L1 initially stored in the microcomputer 73, and stored in the microcomputer 73.
【００３８】出力補正スタートスイッチをＯＦＦにし
て、センサ印加電圧ＶをＶａに切り換え、通常の水蒸気
濃度を測定する状態に戻す。このときにセンサ１に劣化
があると、水蒸気濃度に応じて出力する第２の拡散制限
電流値がＩL2からＩL2’に変化する（図８(b)）。
ＩL2’に対応した水蒸気濃度出力信号ＳL2’がマイコン
７３に入力され、酸素濃度補正係数ｋが乗じられて、補
正信号ｋ＊ＳL2’がＳL2に代わってＰH＝ｆ（ＳL2）と
照合され、水蒸気濃度が補正演算されて水蒸気濃度表示
部７４に表示される。The output correction start switch is turned off, the sensor applied voltage V is switched to Va, and the normal water vapor concentration measurement state is restored. At this time, if there is a deterioration in the sensor 1, the second diffusion limit current value to be output in accordance with the water vapor concentration is changed to I L2 'from I L2 (Figure 8 (b)).
I L2 'steam density output signal S L2 corresponding to' is inputted to the microcomputer 73, the oxygen concentration correction coefficient k is multiplied by the correction signal k * S L2 'on behalf of the S L2 P H = f (S L2 ), The water vapor concentration is corrected and calculated and displayed on the water vapor concentration display portion 74.
【００３９】既述の通り、ＩL1／ＩL2＝一定であるから
ＳL1／ＳL2＝一定である。従って、ＳL1／ＳL1’＝ＳL2
／ＳL2’＝ｋとなる。こうしてｋ＊ＳL2’＝ＳL2である
から、センサの劣化の程度に係わらず水蒸気濃度出力は
補正されて正しい値となる。As described above, since I L1 / I L2 = constant, S L1 / S L2 = constant. Therefore, S L1 / S L1 '= S L2
/ S L2 '= k. Thus, since k * S L2 '= S L2 , the water vapor concentration output is corrected to a correct value regardless of the degree of deterioration of the sensor.
【００４０】本例では、センサとして図１に示す構造の
ものを用いたが、図９や図１０に示すような他の構造の
センサにも適用可能であることはいうまでもない。図９
に示すセンサは、冒頭で既に説明したが、図１０に示す
センサは、陰極３２を覆う箱体３４自体を多孔質とし
て、これを拡散制限手段に用いるものであり、箱体３４
を図９の微小な孔３３に相当する気体拡散制限孔と兼ね
る構造のものである。In this example, the sensor having the structure shown in FIG. 1 was used, but it goes without saying that the sensor can be applied to sensors having other structures as shown in FIGS. 9 and 10. FIG.
The sensor shown in FIG. 10 has already been described at the beginning, but the sensor shown in FIG. 10 uses the box body 34 itself covering the cathode 32 as a porous body and uses this as diffusion limiting means.
Is also a gas diffusion limiting hole corresponding to the minute hole 33 in FIG.
【図１】実施例の水蒸気濃度測定装置に用いる限界電流
式ガスセンサを示す斜視図である。FIG. 1 is a perspective view showing a limiting current type gas sensor used in a water vapor concentration measuring apparatus of an embodiment.
【図２】図１のＡＡ断面図である。FIG. 2 is a sectional view taken along the line AA of FIG.
【図３】図２の変形例を示す断面図である。FIG. 3 is a cross-sectional view showing a modified example of FIG.
【図４】図１の限界電流式ガスセンサに用いるセラミッ
クヒータを示す一部破断斜視図である。4 is a partially cutaway perspective view showing a ceramic heater used in the limiting current type gas sensor of FIG. 1. FIG.
【図５】限界電流式ガスセンサに印加される電圧対その
センサに流れる電流の特性を示すグラフである。FIG. 5 is a graph showing characteristics of voltage applied to a limiting current type gas sensor versus current flowing through the sensor.
【図６】限界電流式ガスセンサによる水蒸気濃度対第２
の拡散制限電流の関係を示すグラフである。[Fig. 6] Second concentration vs. water vapor concentration by limiting current type gas sensor
4 is a graph showing the relationship of the diffusion limiting current of FIG.
【図７】実施例の水蒸気濃度測定装置の回路システムの
構成を示す図である。FIG. 7 is a diagram showing a configuration of a circuit system of the water vapor concentration measuring apparatus according to the embodiment.
【図８】限界電流式ガスセンサに印加される電圧対その
センサに流れる電流の特性の劣化状況を示すグラフであ
る。FIG. 8 is a graph showing deterioration of characteristics of voltage applied to a limiting current type gas sensor versus current flowing through the sensor.
【図９】この発明に適応可能な他の限界電流式ガスセン
サを示す断面図である。FIG. 9 is a sectional view showing another limiting current type gas sensor applicable to the present invention.
【図１０】この発明に適応可能な他の限界電流式ガスセ
ンサを示す断面図である。FIG. 10 is a sectional view showing another limiting current type gas sensor applicable to the present invention.
１ ガスセンサ ２ 陰電極 ２ａ 陰電極部 ２ｂ リード部 ２ｃ 取り
出し部 ３ 陰電極 ３ａ 陽電極部 ３ｂ リード部 ３ｃ 取り
出し部 ６ ガス導入部 ７ ガス拡散制限部 ４，５，１３，１４ 白金端子 ８ ガス出口孔 ９，１５ 通気孔 １０ 安定化ジルコニア板 ２０ セラミックヒータ1 gas sensor 2 negative electrode 2a negative electrode part 2b lead part 2c lead-out part 3 negative electrode 3a positive electrode part 3b lead part 3c take-out part 6 gas introduction part 7 gas diffusion limiting part 4, 5, 13, 14 platinum terminal 8 gas outlet hole 9,15 Vent hole 10 Stabilized zirconia plate 20 Ceramic heater
Claims (5)
に密着した陰陽一対の電極及び陰極への気体拡散を制限
する気体拡散制限手段を有するセンサを用い、それら電
極間に直流電圧を印加したときの出力信号に基づいて水
蒸気濃度を測定する方法において、 該センサが一定の酸素濃度ＰOに応じて示す酸素濃度出
力信号ＳL1とその後にセンサが同一酸素濃度ＰOに応じ
て示す酸素濃度出力信号ＳL1’との比ＳL1／ＳL1’を求
めてそれを酸素濃度補正係数ｋとし、 センサが水蒸気濃度ＰHに応じて示す水蒸気濃度出力信
号ＳL2’に酸素濃度補正係数ｋを乗じて補正信号ｋ＊Ｓ
L2’を算出し、水蒸気濃度ＰHと劣化前のセンサの水蒸
気濃度出力信号ＳL2との対応関係ＰH＝ｆ（ＳL2）
［ｆ：関数記号］を参照して補正信号ｋ＊ＳL2’から水
蒸気濃度を演算することを特徴とする限界電流式ガスセ
ンサによる水蒸気濃度測定方法。1. A solid electrolyte substrate having oxygen ion conductivity, a pair of Yin-Yo electrodes closely attached thereto, and a sensor having gas diffusion limiting means for limiting gas diffusion to a cathode, when a DC voltage is applied between the electrodes. In the method of measuring the water vapor concentration based on the output signal of the above, the oxygen concentration output signal S L1 indicated by the sensor according to a constant oxygen concentration P O and the oxygen concentration output indicated by the sensor thereafter according to the same oxygen concentration P O it was the oxygen concentration correction coefficient k seeking 'ratio S L1 / S L1 of the' signal S L1, the sensor multiplied by the oxygen concentration correction coefficient k in the steam concentration output signal S L2 'shown in accordance with the water vapor concentration P H Correction signal k * S
L2 'is calculated, and the correspondence relationship between the water vapor concentration P H and the water vapor concentration output signal S L2 of the sensor before deterioration P H = f (S L2 )
A method for measuring water vapor concentration using a limiting current type gas sensor, characterized in that the water vapor concentration is calculated from the correction signal k * S L2 'with reference to [f: function symbol].
に密着した陰陽一対の電極及び陰極への気体拡散を制限
する気体拡散制限手段を有するセンサと該センサが一定
の酸素濃度ＰOに応じて示す酸素濃度出力信号ＳL1とそ
の後にセンサが同一酸素濃度ＰOに応じて示す酸素濃度
出力信号ＳL1’との比ＳL1／ＳL1’を求めてそれを酸素
濃度補正係数ｋとし、センサが水蒸気濃度ＰHに応じて
示す水蒸気濃度出力信号ＳL2’に酸素濃度補正係数ｋを
乗じて補正信号ｋ＊ＳL2’を算出する出力補正演算手段
と、 水蒸気濃度ＰHと劣化前のセンサの水蒸気濃度出力信号
ＳL2との対応関係ＰH＝ｆ（ＳL2）［ｆ：関数記号］を
参照して補正信号ｋ＊ＳL2’から水蒸気濃度を演算する
出力演算手段とを備えたことを特徴とする限界電流式ガ
スセンサによる水蒸気濃度測定装置。2. A sensor having a solid electrolyte substrate having oxygen ion conductivity, a pair of positive and negative electrodes in close contact therewith, and gas diffusion limiting means for limiting gas diffusion to a cathode, and the sensor according to a constant oxygen concentration P O. Thereafter the oxygen concentration output signal S L1 to the sensor it was the oxygen concentration correction coefficient k seeking 'ratio S L1 / S L1 of the' oxygen concentration output signal S L1 shown in accordance with the same oxygen concentration P O shown, sensor An output correction calculation means for calculating a correction signal k * S L2 'by multiplying the water vapor concentration output signal S L2 ' shown according to the water vapor concentration P H by the oxygen concentration correction coefficient k, and the water vapor concentration P H and the sensor before deterioration. the correspondence relationship between the water vapor density output signal S L2 P H = f (S L2): that an output calculating means for calculating a water vapor concentration of with reference to [f function symbol] correction signal k * S L2 ' With a limiting current type gas sensor characterized by The gas concentration measurement device.
きにセンサへの印加電圧を切り換える電圧切り換え手段
を備えた請求項２に記載の水蒸気濃度測定装置。3. The water vapor concentration measuring device according to claim 2, further comprising voltage switching means for switching the voltage applied to the sensor when the oxygen concentration output signal S L1 fluctuates.
に密着した陰陽一対の電極及び陰極への気体拡散を制限
する気体拡散制限手段を有するセンサを用い、それら電
極間に直流電圧を印加したときの出力信号に基づいて水
蒸気濃度を測定する方法において、 該センサが一定の水蒸気濃度ＰHに応じて示す水蒸気濃
度出力信号ＳHとその後にセンサが同一水蒸気濃度ＰHに
応じて示す水蒸気濃度出力信号ＳH’との比ＳH／ＳH’
を求めてそれを水蒸気濃度補正係数ｋとし、 センサが水蒸気濃度ＰHに応じて示す水蒸気濃度出力信
号ＳL2’に水蒸気濃度補正係数ｋを乗じて補正信号ｋ＊
ＳL2’を算出し、水蒸気濃度ＰHと劣化前のセンサの水
蒸気濃度出力信号ＳL2との対応関係ＰH＝ｆ（ＳL2）
［ｆ：関数記号］を参照して補正信号ｋ＊ＳL2’から水
蒸気濃度を演算することを特徴とする限界電流式ガスセ
ンサによる水蒸気濃度測定方法。4. A solid electrolyte substrate having oxygen ion conductivity, a pair of Yin-Yo electrodes closely attached thereto, and a sensor having a gas diffusion limiting unit for limiting gas diffusion to a cathode, when a DC voltage is applied between the electrodes. In the method of measuring the water vapor concentration based on the output signal of the above, the sensor outputs a water vapor concentration output signal S H corresponding to a constant water vapor concentration P H , and thereafter a sensor outputs a water vapor concentration output corresponding to the same water vapor concentration P H. Ratio of signal S H 'S H / S H '
The seeking it as a water vapor concentration correction coefficient k, the sensor is steam concentration P H correction signal is multiplied by the water vapor concentration correction coefficient k in the steam concentration output signal S L2 'shown in accordance with k *
S L2 'is calculated and the correspondence relationship between the water vapor concentration P H and the water vapor concentration output signal S L2 of the sensor before deterioration P H = f (S L2 )
A method for measuring water vapor concentration using a limiting current type gas sensor, characterized in that the water vapor concentration is calculated from the correction signal k * S L2 'with reference to [f: function symbol].
に密着した陰陽一対の電極及び陰極への気体拡散を制限
する気体拡散制限手段を有するセンサと該センサが一定
の水蒸気濃度ＰHに応じて示す水蒸気濃度出力信号ＳHと
その後にセンサが同一水蒸気濃度ＰHに応じて示す水蒸
気濃度出力信号ＳH’との比ＳH／ＳH’を求めてそれを
水蒸気濃度補正係数ｋとし、センサが水蒸気濃度ＰHに
応じて示す水蒸気濃度出力信号ＳL2’に水蒸気濃度補正
係数ｋを乗じて補正信号ｋ＊ＳL2’を算出する出力補正
演算手段と、 水蒸気濃度ＰHと劣化前のセンサの水蒸気濃度出力信号
ＳL2との対応関係ＰH＝ｆ（ＳL2）［ｆ：関数記号］を
参照して補正信号ｋ＊ＳL2’から水蒸気濃度を演算する
出力演算手段とを備えたことを特徴とする限界電流式ガ
スセンサによる水蒸気濃度測定装置。5. A sensor having a solid electrolyte substrate having oxygen ion conductivity, a pair of positive and negative electrodes closely attached thereto, and gas diffusion limiting means for limiting gas diffusion to a cathode, and the sensor according to a constant water vapor concentration P H. then the water vapor concentration output signal S H to the sensor it seeking 'ratio S H / S H of the' water vapor concentration output signal S H and the water vapor concentration correction coefficient k shown in accordance with the same water vapor concentration P H shown, sensor An output correction calculation means for calculating a correction signal k * S L2 'by multiplying a water vapor concentration output signal S L2 ' corresponding to the water vapor concentration P H by a water vapor concentration correction coefficient k, and a water vapor concentration P H and a sensor before deterioration. the correspondence relationship between the water vapor density output signal S L2 P H = f (S L2): that an output calculating means for calculating a water vapor concentration of with reference to [f function symbol] correction signal k * S L2 ' Limiting current type gas sensor characterized by Water vapor concentration measuring device according to.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP10319096A JP3421192B2 (en) | 1996-03-29 | 1996-03-29 | Method for measuring water vapor concentration by limiting current type gas sensor and apparatus for measuring water vapor concentration using the method |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP10319096A JP3421192B2 (en) | 1996-03-29 | 1996-03-29 | Method for measuring water vapor concentration by limiting current type gas sensor and apparatus for measuring water vapor concentration using the method |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH09269313A true JPH09269313A (en) | 1997-10-14 |
| JP3421192B2 JP3421192B2 (en) | 2003-06-30 |
Family
ID=14347610
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP10319096A Expired - Lifetime JP3421192B2 (en) | 1996-03-29 | 1996-03-29 | Method for measuring water vapor concentration by limiting current type gas sensor and apparatus for measuring water vapor concentration using the method |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP3421192B2 (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2014196995A (en) * | 2013-03-08 | 2014-10-16 | ローム株式会社 | Limiting current type gas sensor, method for manufacturing limiting current type gas sensor and sensor network system |
| JP2016194288A (en) * | 2015-04-02 | 2016-11-17 | トヨタ自動車株式会社 | Abnormality diagnosis system for gas sensor |
-
1996
- 1996-03-29 JP JP10319096A patent/JP3421192B2/en not_active Expired - Lifetime
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2014196995A (en) * | 2013-03-08 | 2014-10-16 | ローム株式会社 | Limiting current type gas sensor, method for manufacturing limiting current type gas sensor and sensor network system |
| JP2016194288A (en) * | 2015-04-02 | 2016-11-17 | トヨタ自動車株式会社 | Abnormality diagnosis system for gas sensor |
Also Published As
| Publication number | Publication date |
|---|---|
| JP3421192B2 (en) | 2003-06-30 |
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