JPH1019843A - Apparatus and method for detecting concentration of combustible material - Google Patents
Apparatus and method for detecting concentration of combustible materialInfo
- Publication number
- JPH1019843A JPH1019843A JP8188571A JP18857196A JPH1019843A JP H1019843 A JPH1019843 A JP H1019843A JP 8188571 A JP8188571 A JP 8188571A JP 18857196 A JP18857196 A JP 18857196A JP H1019843 A JPH1019843 A JP H1019843A
- Authority
- JP
- Japan
- Prior art keywords
- oxygen
- concentration
- gap
- combustible substance
- pumping cell
- 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.)
- Pending
Links
Abstract
Description
【０００１】[0001]
【発明の属する技術分野】本発明は、たとえば燃焼器や
内燃機関の排ガス中に含まれる炭化水素（ＨＣ）等の可
燃物質の濃度を検出するために使用される可燃物質濃度
検出器及び可燃物質濃度の検出方法に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a combustible substance concentration detector and a combustible substance used for detecting the concentration of combustible substances such as hydrocarbons (HC) contained in exhaust gas of a combustor or an internal combustion engine. It relates to a method for detecting a concentration.
【０００２】[0002]
【従来の技術】従来より排ガス中に含まれる炭化水素等
の可燃物質は三元触媒により燃焼除去されている。この
触媒の活性劣化は炭化水素等の濃度から推測することが
できるが、その検知方法として、例えば、ＳＡＥ ｐａ
ｐｅｒ Ｎｏ．９４２０５７ｐａｇｅ．１〜４４（１９
９４）に示されているように、２本の酸素センサ（ＥＧ
Ｏセンサ）を用いる方法が提案されている。これは、排
ガス浄化用の触媒の上流側（触媒前）と下流側（触媒
後）にそれぞれ酸素センサを取り付け、上流側の酸素セ
ンサの起電力の最大値と最小値との差（△ｍＶ1）と、
下流側の酸素センサの起電力の最大値と最小値との差
（△ｍＶ2）とから、これらの比（△ｍＶ2／△ｍＶ1）
を求めるものである。この比（△ｍＶ2／△ｍＶ1）がゼ
ロに近いほど触媒活性が高く、触媒が劣化してくると比
（△ｍＶ2／△ｍＶ1）が急激に大きくなることから、触
媒の劣化度合いを検知するというものである。2. Description of the Related Art Conventionally, combustible substances such as hydrocarbons contained in exhaust gas have been burned and removed by a three-way catalyst. The activity deterioration of the catalyst can be inferred from the concentration of hydrocarbons and the like. As a detection method, for example, SAE pa
per No. 942057 page. 1-44 (19
94), two oxygen sensors (EG
O sensor) has been proposed. This is because oxygen sensors are attached to the upstream side (before the catalyst) and the downstream side (after the catalyst) of the exhaust gas purifying catalyst, respectively, and the difference between the maximum value and the minimum value of the electromotive force of the upstream oxygen sensor (△ mV 1 )When,
From the difference (△ mV 2 ) between the maximum value and the minimum value of the electromotive force of the downstream oxygen sensor, these ratios (△ mV 2 / △ mV 1 )
Is what you want. The closer this ratio (△ mV 2 / △ mV 1 ) is to zero, the higher the catalytic activity, and when the catalyst deteriorates, the ratio (△ mV 2 / △ mV 1 ) rapidly increases. Is detected.
【０００３】また、２本の全領域空燃比センサ（ＵＥＧ
Ｏセンサ）を用い、これを触媒の上流側及び下流側にそ
れぞれ取り付け、上流側（触媒前）の空気過剰率λの最
大値と最小値の差（△λ1）と、下流側（触媒後）の空
気過剰率λの最大値と最小値の差（△λ2）とをそれぞ
れ求め、これらの比（△λ2／△λ1）から触媒の劣化度
合いを検知する方法もある。この比（△λ2／△λ1）と
炭化水素の転換率とは、同転換率が４０〜１００％の範
囲において直線関係が得られており、この方法で触媒の
劣化度合いを検知することが開示されている。In addition, two full-range air-fuel ratio sensors (UEG
O sensors), which are attached to the upstream and downstream sides of the catalyst, respectively, and the difference between the maximum value and the minimum value (△ λ 1 ) of the excess air ratio λ on the upstream side (before the catalyst) and the downstream side (after the catalyst). )), The difference (△ λ 2 ) between the maximum value and the minimum value of the excess air ratio λ is determined, and the deterioration degree of the catalyst is detected from the ratio (△ λ 2 / △ λ 1 ). This ratio (△ λ 2 / △ λ 1 ) and the conversion rate of hydrocarbons have a linear relationship in the conversion rate range of 40 to 100%, and the degree of catalyst deterioration can be detected by this method. Is disclosed.
【０００４】ここで用いられる全領域空燃比センサ（Ｕ
ＥＧＯセンサ）としては、例えば図１７に示されるよう
な構造のものが知られている。図１７は従来のＵＥＧＯ
センサの先端部の断面図であり、４１は拡散通路、４２
は空隙部、４３は酸素ポンピングセル、４４は酸素濃度
測定セル、４５は加熱ヒータである。酸素ポンピングセ
ル４３及び酸素濃度測定セル４４は、薄板状ジルコニア
からなる固体電解質層の両面に、多孔質白金又は多孔質
ロジウムからなる電極４３−ａ、４３−ｂ、４４−ａ及
び４４−ｂがそれぞれ設けられている。以下、本明細書
では、酸素ポンピングセルや酸素濃度測定セルを合わせ
て酸素セルと呼ぶこともある。The full-range air-fuel ratio sensor (U
As an EGO sensor, for example, one having a structure as shown in FIG. 17 is known. FIG. 17 shows a conventional UEGO.
It is sectional drawing of the front-end | tip part of a sensor, 41 is a diffusion path, 42
Is a void, 43 is an oxygen pumping cell, 44 is an oxygen concentration measurement cell, and 45 is a heater. In the oxygen pumping cell 43 and the oxygen concentration measuring cell 44, electrodes 43-a, 43-b, 44-a and 44-b made of porous platinum or rhodium are provided on both surfaces of a solid electrolyte layer made of sheet zirconia. Each is provided. Hereinafter, in this specification, the oxygen pumping cell and the oxygen concentration measuring cell may be collectively referred to as an oxygen cell.
【０００５】[0005]
【発明が解決しようとする課題】上記の方法において、
２本の酸素センサ（ＥＧＯセンサ）を使用する方法で
は、酸素貯蔵能力を間接的にモニタリングしているた
め、炭化水素等の濃度を直接的に測定することができ
ず、精度がよくないという問題がある。また、２本の全
領域空燃比センサ（ＵＥＧＯセンサ）を使用する方法で
あっても、炭化水素等の濃度に対するセンサ出力が小さ
いため、高精度な炭化水素等の濃度の検出ができないと
いう問題がある。In the above method,
In the method using two oxygen sensors (EGO sensors), since the oxygen storage capacity is indirectly monitored, the concentration of hydrocarbons or the like cannot be directly measured, resulting in poor accuracy. There is. Further, even in the method using two full-range air-fuel ratio sensors (UEGO sensors), the sensor output with respect to the concentration of hydrocarbons or the like is small, so that the concentration of hydrocarbons or the like cannot be detected with high accuracy. is there.
【０００６】本発明は、被測定ガス中の炭化水素等の可
燃物質濃度を高精度で検出でき、小型で安価な可燃物質
濃度検出器の提供を目的とする。また、本発明は、被測
定ガス中の可燃物質を実用レベルにおいて高精度で検出
可能な可燃物質濃度の検出方法を提供することを目的と
する。さらに、本発明は、自動車排ガス用三元触媒のモ
ニタリングが精度よく可能な触媒装置のモニタリング方
法を提供することを目的とする。An object of the present invention is to provide a small and inexpensive combustible substance concentration detector capable of detecting the concentration of combustible substances such as hydrocarbons in a gas to be measured with high accuracy. Another object of the present invention is to provide a method for detecting a combustible substance concentration capable of detecting a combustible substance in a gas to be measured with high accuracy at a practical level. Further, another object of the present invention is to provide a method for monitoring a catalyst device capable of accurately monitoring a three-way catalyst for automobile exhaust gas.
【０００７】[0007]
【課題を解決するための手段】本発明の請求項１に係る
可燃物質濃度検出器は、薄板状の酸素イオン導電体より
なる固体電解質層を多孔質の電極で挟んでなる第１酸素
ポンピングセル及び酸素濃度測定セルを有する第１空隙
部と、薄板状の酸素イオン導電体よりなる固体電解質層
を多孔質の電極で挟んでなる第２酸素ポンピングセルを
有する第２空隙部と、第１空隙部を被測定ガス側に連通
する第１拡散通路と、第１空隙部を第２空隙部に連通す
る第２拡散通路とを備えてなることを特徴とする。According to a first aspect of the present invention, there is provided a combustible substance concentration detector comprising: a first oxygen pumping cell in which a solid electrolyte layer made of a thin plate-like oxygen ion conductor is sandwiched between porous electrodes; And a first gap having an oxygen concentration measurement cell, a second gap having a second oxygen pumping cell in which a solid electrolyte layer made of a thin plate oxygen ion conductor is sandwiched between porous electrodes, and a first gap. A first diffusion passage communicating the portion with the measured gas side, and a second diffusion passage communicating the first gap with the second gap.
【０００８】本発明の請求項２に係る可燃物質濃度検出
器は、薄板状の酸素イオン導電体よりなる固体電解質層
を多孔質の電極で挟んでなる第１酸素ポンピングセル及
び酸素濃度測定セルを有する第１空隙部と、薄板状の酸
素イオン導電体よりなる固体電解質層を多孔質の電極で
挟んでなる第２酸素ポンピングセルを有する第２空隙部
と、第１空隙部を被測定ガス側に連通する第１拡散通路
と、第１空隙部を第２空隙部に連通する第２拡散通路と
を備える固体電解質層が積層されてなる可燃物質濃度検
出器であって、第１酸素ポンピングセル、酸素濃度測定
セル及び第２酸素ポンピングセルがいずれも互いに異な
る固体電解質層に設けられていることを特徴とする。According to a second aspect of the present invention, there is provided a combustible substance concentration detector comprising a first oxygen pumping cell and an oxygen concentration measurement cell each having a thin plate-like solid electrolyte layer made of an oxygen ion conductor sandwiched between porous electrodes. A first void portion, a second void portion having a second oxygen pumping cell in which a solid electrolyte layer made of a thin plate-like oxygen ion conductor is sandwiched between porous electrodes, and a first void portion facing the gas to be measured. Combustible substance concentration detector comprising a solid electrolyte layer having a first diffusion passage communicating with a first diffusion passage and a second diffusion passage communicating the first gap with the second gap, the first oxygen pumping cell , The oxygen concentration measuring cell and the second oxygen pumping cell are all provided in different solid electrolyte layers.
【０００９】[0009]
【発明実施の形態】前記酸素イオン導電体としてはジル
コニアセラミックスからなる固体電解質が好ましい。ジ
ルコニアセラミックスとしては、ジルコニアとイットリ
アの固溶体やジルコニアとカルシアの固溶体が代表的な
ものであるが、他にハフニアの固溶体、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も使用でき
る。固体電解質の表面に設ける多孔質の電極としては、
触媒機能を有する白金やロジウムあるいはその合金を使
用するのが好ましい。その形成方法は、たとえば白金粉
末に固体電解質と同じ材料の粉末を混合したものをペー
スト状とし、固体電解質層上にスクリーン印刷し、次い
で焼結する厚膜形成方法や溶射による皮膜形成方法があ
る。また、拡散通路には、細い貫通孔を有するセラミッ
クスや通気性のある多孔質セラミックスを使用するのが
好ましい。BEST MODE FOR CARRYING OUT THE INVENTION The oxygen ion conductor is preferably a solid electrolyte made of zirconia ceramics. Representative examples of the zirconia ceramics include a solid solution of zirconia and yttria and a solid solution of zirconia and calcia. In addition, a solid solution of hafnia, a perovskite-type oxide solid solution, and a trivalent metal oxide solid solution can also be used. As a porous electrode provided on the surface of the solid electrolyte,
It is preferable to use platinum, rhodium, or an alloy thereof having a catalytic function. As a forming method, for example, there is a method of forming a thick film by mixing a powder of the same material as a solid electrolyte with platinum powder to form a paste, screen printing on a solid electrolyte layer, and then sintering, or a method of forming a film by thermal spraying. . Further, it is preferable to use ceramics having fine through holes or porous ceramics having air permeability for the diffusion passage.
【００１０】本発明の請求項２に係る可燃物質濃度検出
器においては、特に、第１酸素ポンピングセル、酸素濃
度測定セル及び第２酸素ポンピングセルがいずれも互い
に異なる固体電解質層に設けられていることを特徴とす
る。この特徴によって本発明の可燃物質濃度検出器で
は、酸素濃度測定セルと第２酸素ポンピングセルの電極
間に生じる電流リークが顕著に減少し、第１空隙部内の
酸素濃度の測定精度が向上して第１空隙部内の酸素濃度
を精度よく制御することができる。これによって第１空
隙部内の酸素濃度を可燃物質の燃焼分解に必要な酸素濃
度レベルに安定して制御できるので、微量である排ガス
中の可燃物質濃度の検出精度が顕著に向上する。本発明
による上述の構造を有する可燃物質濃度検出器は、セラ
ミックス多層基板の製造技術をセラミック固体電解質材
料に適用することによって、小型の可燃物質濃度検出器
を生産性よく安価に製造でき、かつ提供できる。[0010] In the combustible substance concentration detector according to claim 2 of the present invention, in particular, the first oxygen pumping cell, the oxygen concentration measuring cell, and the second oxygen pumping cell are all provided on different solid electrolyte layers. It is characterized by the following. Due to this feature, in the combustible substance concentration detector of the present invention, the current leak generated between the electrodes of the oxygen concentration measurement cell and the second oxygen pumping cell is significantly reduced, and the measurement accuracy of the oxygen concentration in the first gap is improved. The oxygen concentration in the first gap can be controlled with high accuracy. As a result, the oxygen concentration in the first gap can be stably controlled to the oxygen concentration level required for the combustion decomposition of the combustible substance, so that the detection accuracy of the concentration of the combustible substance in the minute amount of exhaust gas is remarkably improved. The combustible substance concentration detector having the above-described structure according to the present invention can provide a small-sized combustible substance concentration detector with good productivity and at low cost by applying a ceramic multilayer substrate manufacturing technique to a ceramic solid electrolyte material. it can.
【００１１】また、本発明の好ましい可燃物質濃度検出
器（単に検出器という場合もある。）では、固体電解質
層の間に設けられた絶縁膜又は絶縁層によって、酸素濃
度測定セルの電極が第１酸素ポンピングセル及び第２酸
素ポンピングセルの電極と電気的に絶縁されている。同
じ層の固体電解質に２つ以上の酸素濃度セルが設けられ
ている可燃物質濃度検出器の場合に比べて電極間の完全
な絶縁が可能であり、固体電解質層の間に設けた絶縁膜
又は絶縁層によって電極相互間の電流リークを完全に防
止することができる。上記絶縁膜又は絶縁層としてはセ
ラミックスであることが好ましく、高純度アルミナから
なることは特に好ましい。高純度アルミナは高温下での
絶縁性が良好であり、またジルコニアの固体電解質層と
の同時焼成も可能であり、さらに原料の入手も容易であ
る。Further, in the preferred combustible substance concentration detector of the present invention (sometimes simply referred to as a detector), the electrode of the oxygen concentration measurement cell is formed by an insulating film or an insulating layer provided between the solid electrolyte layers. It is electrically insulated from the electrodes of the first oxygen pumping cell and the second oxygen pumping cell. Compared to the case of a combustible substance concentration detector in which two or more oxygen concentration cells are provided in the same layer of solid electrolyte, complete insulation between the electrodes is possible, and an insulating film provided between the solid electrolyte layers or A current leak between the electrodes can be completely prevented by the insulating layer. The insulating film or the insulating layer is preferably made of ceramics, and is particularly preferably made of high-purity alumina. High-purity alumina has good insulation properties at high temperatures, can be co-fired with a zirconia solid electrolyte layer, and can easily obtain raw materials.
【００１２】このような構成とした可燃物質濃度検出器
では、酸素濃度測定セルの測定精度が向上し、第１空隙
部の酸素濃度を精度よく制御できるので、可燃物質濃度
の検出精度がさらに向上し、低濃度の可燃物質濃度も精
度よく検出できる。絶縁膜はすべての固体電解質層の間
に設けてもよいが、絶縁を必要とする固体電解質層の間
にだけ設けてもよい。また、絶縁膜を設ける代わりに、
酸素セルを設けない固体電解質層をアルミナなどからな
る絶縁層で置き換えてもよい。In the flammable substance concentration detector having such a configuration, the measurement accuracy of the oxygen concentration measuring cell is improved, and the oxygen concentration in the first gap can be controlled with high accuracy, so that the detection accuracy of the flammable substance concentration is further improved. However, even low-concentration combustible substance concentrations can be accurately detected. The insulating film may be provided between all the solid electrolyte layers, or may be provided only between the solid electrolyte layers requiring insulation. Also, instead of providing an insulating film,
The solid electrolyte layer without the oxygen cell may be replaced with an insulating layer made of alumina or the like.
【００１３】本発明の他の好ましい可燃物質濃度検出器
では、第２空隙部が多孔質材料で充填されている。たと
えば、第２拡散通路と第２空隙部に同じ多孔質材料が充
填されており、これによって第２空隙部の有効容積が顕
著に小さくなる。第２空隙部の有効容積が小さくなれ
ば、可燃物質検出器が可燃物質を検知する応答性が顕著
に向上する。この第２空隙部の容積は、０．１ｍｍ3以
下、あるいは第１空隙部の容積の５０％以下とするのが
好ましい。[0013] In another preferred combustible substance concentration detector of the present invention, the second void portion is filled with a porous material. For example, the second diffusion passage and the second gap are filled with the same porous material, so that the effective volume of the second gap is significantly reduced. When the effective volume of the second gap is reduced, the responsiveness of the combustible substance detector to detect the combustible substance is significantly improved. The volume of the second gap is preferably 0.1 mm 3 or less, or 50% or less of the volume of the first gap.
【００１４】本発明の他の好ましい可燃物質濃度検出器
では、第１酸素ポンピングセルの第１空隙部側に設けた
多孔質の電極が白金、ロジウム、パラジウム、イリジウ
ム、レニウムから選ばれるいずれかの金属又はその合金
からなり、他の電極が白金又は白金合金からなるものが
好ましい。特にロジウムを含む多孔質の電極には可燃物
質を燃焼分解する触媒機能があるので、検出器のセンサ
部の温度をそれほど高くしなくても第１空隙部中の可燃
物質を完全に燃焼分解でき、低濃度の可燃物質を第１酸
素ポンピングセルの電流値として検出できる。In another preferred combustible substance concentration detector of the present invention, the porous electrode provided on the first void side of the first oxygen pumping cell is any one selected from platinum, rhodium, palladium, iridium and rhenium. Preferably, the electrode is made of a metal or an alloy thereof, and the other electrode is made of platinum or a platinum alloy. In particular, since the porous electrode containing rhodium has a catalytic function of burning and decomposing the combustible material, the combustible material in the first void portion can be completely burned and decomposed without increasing the temperature of the sensor part of the detector so much. The low-concentration combustible substance can be detected as the current value of the first oxygen pumping cell.
【００１５】また、上記の多孔質の電極は、Ａｇ，Ａ
ｕ，Ｎｉ，Ｃｏ，Ｃｒ，Ｆｅ，Ｍｎ，Ｃｕ，Ｔｉ，Ａ
ｌ，Ｐｂ，Ｚｎ，Ｓｎ，Ｉｎから選ばれる少なくとも１
種を含有するものであってもよい。なお、第２空隙部に
設けた多孔質の電極は特に限定されないが、好ましく
は、白金、ロジウム、パラジウム、イリジウム、レニウ
ムから選ばれるいずれかの金属又はその合金、さらには
これらとＡｇ，Ａｕ，Ｎｉ，Ｃｏ，Ｃｒ，Ｆｅ，Ｍｎ，
Ｃｕ，Ｔｉ，Ａｌ，Ｐｂ，Ｚｎ，Ｓｎ，Ｉｎから選ばれ
る少なくとも１種とを含有するものの中から選択して用
いることができる。Further, the above porous electrode is made of Ag, A
u, Ni, Co, Cr, Fe, Mn, Cu, Ti, A
at least one selected from l, Pb, Zn, Sn, In
It may contain seeds. The porous electrode provided in the second void portion is not particularly limited, but is preferably a metal selected from platinum, rhodium, palladium, iridium, and rhenium or an alloy thereof, and furthermore, Ag, Au, Ni, Co, Cr, Fe, Mn,
It can be selected from those containing at least one selected from Cu, Ti, Al, Pb, Zn, Sn, and In.
【００１６】本発明の他の好ましい可燃物質濃度検出器
では、可燃物質濃度検出器を固体電解質層に垂直な方向
に投影したとき、第１空隙部と第２空隙部とが互いに概
ね重なり合う位置にあり、第１空隙部と第２空隙部の間
の固体電解質層を貫通して固体電解質層に垂直な方向に
伸びる第２拡散通路によって第１空隙部と第２空隙部と
が連通されている。In another preferred combustible substance concentration detector of the present invention, when the combustible substance concentration detector is projected in a direction perpendicular to the solid electrolyte layer, the first gap portion and the second gap portion are located at positions substantially overlapping each other. The first gap and the second gap are communicated with each other by a second diffusion passage extending through the solid electrolyte layer between the first gap and the second gap in a direction perpendicular to the solid electrolyte layer. .
【００１７】この構成の可燃物質濃度検出器では、例え
ば被測定ガスである排ガスが流れる管の管壁に設けた穴
から棒状に形成されたセンサ部を管内に挿入するとき、
センサ部の各酸素セルの管壁からの距離がほぼ等しくな
るので、熱伝導などによって検出器の長手方向に温度勾
配があっても、各酸素セル間に温度差が生じないので検
出値に誤差がもたらされないという利点がある。また、
検出器の第１空隙部内の可燃物質を燃焼分解できるよう
に、検出器をある程度の高温に保持する必要がある。こ
のとき、空隙部が互いに重なり合っているセンサ部構成
を採用することによって、温度保持のために付設する面
状の発熱部を有する加熱ヒータの発熱部を小さくでき、
各酸素セルの管壁からの距離が等しくなるので、管内の
温度分布や検出器を通しての熱伝導による温度差に影響
されにくく、検出器の各酸素セルの温度を一定温度に制
御しやすい。In the flammable substance concentration detector having this configuration, for example, when a rod-shaped sensor section is inserted into a pipe through a hole provided in a pipe wall of the pipe through which the exhaust gas to be measured flows,
Since the distance between the sensor unit and the tube wall of each oxygen cell is almost equal, even if there is a temperature gradient in the longitudinal direction of the detector due to heat conduction, etc., there is no temperature difference between the oxygen cells, so there is an error in the detected value. Is not brought. Also,
The detector needs to be maintained at a certain high temperature so that the combustible material in the first gap portion of the detector can be burned and decomposed. At this time, by adopting a sensor configuration in which the voids overlap each other, the heat generating portion of the heater having a planar heat generating portion attached for maintaining the temperature can be reduced,
Since the distances of the respective oxygen cells from the tube wall become equal, the oxygen cells are hardly affected by the temperature distribution in the tubes and the temperature difference due to heat conduction through the detector, and the temperature of each oxygen cell of the detector can be easily controlled to a constant temperature.
【００１８】本発明の他の好ましい可燃物質濃度検出器
では、積層された固体電解質層に面状の発熱部を有する
加熱ヒータを設けた層が積層され、可燃物質濃度検出器
を固体電解質層に垂直な方向に投影したとき、第１空隙
部、第２空隙部及び面状の発熱部が互いに概ね重なり合
う位置にある。加熱ヒータは、酸素濃度測定セルの温度
を一定値に保持し、第１空隙部の温度を高くしやすいよ
うに、互いに概ね重なり合う位置に積層するのが好まし
い。ここで面状の発熱部というのは、ヒータ線が一平面
上に屈曲して設けられているものを含む。なお、加熱ヒ
ータは１枚でも十分であるが、たとえば２枚用いてセン
サ部をその間に配置するサンドイッチ構造にすることも
できる。なお、加熱ヒータと固体電解質層との間に外気
に通じる外気連絡通路を設ければ、各酸素ポンピングセ
ルにより各空隙部から抜き取った酸素ガスを排出した
り、各空隙部に汲み入れる酸素を供給したりすることが
容易にできる。In another preferred combustible substance concentration detector of the present invention, a layer provided with a heater having a planar heating portion is laminated on the laminated solid electrolyte layer, and the combustible substance concentration detector is connected to the solid electrolyte layer. When projected in the vertical direction, the first gap, the second gap, and the planar heat generating portion are located at positions substantially overlapping each other. The heaters are preferably stacked at positions substantially overlapping each other so that the temperature of the oxygen concentration measurement cell is maintained at a constant value and the temperature of the first gap is easily increased. Here, the planar heat generating portion includes one in which the heater wire is provided to be bent on one plane. Although one heater is sufficient, a sandwich structure in which, for example, two heaters are used and the sensor unit is disposed therebetween may be used. In addition, if an outside air communication passage communicating with the outside air is provided between the heater and the solid electrolyte layer, each oxygen pumping cell discharges the oxygen gas extracted from each gap and supplies oxygen pumped into each gap. Can be easily done.
【００１９】可燃物質濃度検出器に付設する加熱ヒータ
は、通常酸素濃度測定セルの部分の温度を７００℃〜８
５０℃に保持できるものが好ましい。この条件を充たす
加熱ヒータとしては、加熱ヒータの発熱部をセラミック
スと白金又は白金合金の複合材料とし、加熱ヒータのリ
ード部を白金又は白金合金としたものを使用するのが好
ましい。また、加熱ヒータのリード部の常温抵抗値を加
熱ヒータ全体の常温抵抗値の３０％以下とするのが好ま
しい。リード部の抵抗値を小さくすれば、検出器を加熱
するための電気エネルギのロスを少なくできる。The heater attached to the combustible substance concentration detector usually adjusts the temperature of the oxygen concentration measurement cell from 700 ° C. to 8 ° C.
Those which can be maintained at 50 ° C. are preferred. As a heater satisfying this condition, it is preferable to use a heater whose heating part is made of a composite material of ceramics and platinum or a platinum alloy, and whose lead part is made of platinum or a platinum alloy. Further, it is preferable that the normal temperature resistance value of the lead portion of the heater be 30% or less of the normal temperature resistance value of the entire heater. If the resistance value of the lead portion is reduced, the loss of electric energy for heating the detector can be reduced.
【００２０】なお、第１空隙部と第２空隙部とは、必ず
しも薄板状の固体電解質層の厚さ方向に連結して配置さ
れていなくてもよく、固体電解質層の面方向に並置する
形で配置して、その間を拡散通路で連結する構造のもの
であってもよい。The first gap and the second gap may not necessarily be connected to each other in the thickness direction of the thin plate-like solid electrolyte layer, but may be juxtaposed in the plane direction of the solid electrolyte layer. And a structure in which they are connected by a diffusion path.
【００２１】本発明の可燃物質濃度の検出方法は、薄板
状の酸素イオン導電体からなる固体電解質層が多孔質の
電極で挟まれた第１酸素ポンピングセル及び酸素濃度測
定セルを有する第１空隙部と、薄板状の酸素イオン導電
体からなる固体電解質層が多孔質の電極で挟まれた第２
酸素ポンピングセルを有する第２空隙部と、第１空隙部
を被測定ガス側と連通する第１拡散通路と、第１空隙部
を第２空隙部に連通する第２拡散通路とを備えてなる可
燃物質濃度検出器を用い、第１拡散通路を通して第１空
隙部に導入した被測定ガス中の可燃物質を前記多孔質の
電極上で燃焼させ、酸素濃度測定セルで酸素濃度を監視
しつつ第１酸素ポンピングセルにより酸素を導入して第
１空隙部の酸素濃度を制御し、所定の酸素濃度とした被
測定ガスを第２拡散通路を通して第２空隙部に導入し、
第２酸素ポンピングセルに一定電圧を印加して第２空隙
部内の酸素を抜き取り、このとき第１酸素ポンピングセ
ルに流れるポンプ電流Ｉｐ1または第２酸素ポンピング
セルに流れるポンプ電流Ｉｐ2に基いて被測定ガス中の
可燃物質濃度を検出することを特徴とする。According to the method for detecting the concentration of combustible material of the present invention, a first gap having a first oxygen pumping cell and an oxygen concentration measuring cell in which a solid electrolyte layer made of a thin plate of an oxygen ion conductor is sandwiched between porous electrodes. And a solid electrolyte layer made of a thin plate-shaped oxygen ion conductor sandwiched between porous electrodes.
A second gap having an oxygen pumping cell; a first diffusion passage connecting the first gap to the measured gas side; and a second diffusion passage connecting the first gap to the second gap. Using a combustible substance concentration detector, combustible substances in the gas to be measured introduced into the first gap through the first diffusion path are burned on the porous electrode, and the oxygen concentration is monitored by an oxygen concentration measurement cell while monitoring the oxygen concentration. (1) oxygen is introduced by an oxygen pumping cell to control the oxygen concentration in the first gap, and a gas to be measured having a predetermined oxygen concentration is introduced into the second gap through the second diffusion passage;
Extracting oxygen in the second gap portion by applying a constant voltage to the second oxygen pumping cell, the this time based on the pump current Ip 2 flowing through the pump current Ip 1 or the second oxygen pumping cell flowing in the first oxygen pumping cell It is characterized in that the concentration of combustible substances in the measurement gas is detected.
【００２２】すなわち、前述の可燃物質濃度検出器を使
用した可燃物質濃度の検出方法である。まず、一定の酸
素分圧に制御された第１空隙部中に第１拡散通路を通し
て被測定ガスが導入される。ここで被測定ガス中の可燃
物質（一酸化炭素や炭化水素等）が触媒機能を有する多
孔質の電極と接して燃焼分解されると、電極近傍の酸素
濃度が低下するため、その低下分を補うよう第１酸素ポ
ンピングセルにより外部から酸素を第１空隙部に汲み込
む。汲み込まれた酸素を含む被測定ガスを第２拡散通路
を通して第２空隙部に導入し、第２空隙部に設けた第２
酸素ポンピングセルに一定電圧、例えば４５０ｍＶを印
加して第２空隙部内に導入した被測定ガス中の酸素を汲
み出す。That is, there is provided a method for detecting a combustible substance concentration using the above-described combustible substance concentration detector. First, the gas to be measured is introduced through the first diffusion passage into the first void controlled at a constant oxygen partial pressure. Here, if a combustible substance (carbon monoxide, hydrocarbon, etc.) in the gas to be measured comes into contact with a porous electrode having a catalytic function and is decomposed by combustion, the oxygen concentration in the vicinity of the electrode decreases. Oxygen is externally pumped into the first cavity by the first oxygen pumping cell to compensate. The pumped gas to be measured including oxygen is introduced into the second gap through the second diffusion passage, and the second gas provided in the second gap is provided.
A constant voltage, for example, 450 mV is applied to the oxygen pumping cell to pump out the oxygen in the gas to be measured introduced into the second gap.
【００２３】このときの第１酸素ポンピングセルに流れ
る電流値または第２酸素ポンピングセルに流れる電流値
のいずれかを演算処理することにより、被測定ガス中の
可燃物質濃度が求められる。２つの酸素ポンピングセル
に流れる電流（ポンプ電流ともいう）の大きさは、いず
れも可燃物質の濃度に対応したものとなるので、どちら
の電流値を用いてもよい。ただし、第２酸素ポンピング
セルのポンプ電流の方が、ポンピング効果により増幅さ
れて出力されるため、ノイズの影響を受け難く、より高
い精度で可燃物質濃度を検出することができる点で好ま
しい。At this time, the concentration of the combustible substance in the gas to be measured is obtained by calculating either the current value flowing through the first oxygen pumping cell or the current value flowing through the second oxygen pumping cell. Since the magnitudes of the currents (also called pump currents) flowing through the two oxygen pumping cells correspond to the concentrations of the combustible substances, either current value may be used. However, since the pump current of the second oxygen pumping cell is amplified and output by the pumping effect, the pump current is less likely to be affected by noise, and the concentration of the combustible substance can be detected with higher accuracy.
【００２４】なお、第１空隙部中の酸素分圧は、窒素酸
化物（ＮＯｘ）の影響を低減するため、ＮＯｘが分解さ
れる程度の低酸素濃度に一定に制御する必要がある。そ
のためには、酸素濃度測定セルの起電力が一定値（例え
ば２００ｍＶ〜４５０ｍＶ）となるように第１酸素ポン
ピングセルを制御すればよい。このとき、酸素濃度測定
セルの起電力が２００ｍＶの場合の酸素分圧は１０-4ａ
ｔｍ、４５０ｍＶの場合の酸素分圧は１０-9ａｔｍとな
る。It is necessary to control the oxygen partial pressure in the first gap to a low oxygen concentration at which NOx is decomposed in order to reduce the influence of nitrogen oxides (NOx). For that purpose, the first oxygen pumping cell may be controlled so that the electromotive force of the oxygen concentration measurement cell becomes a constant value (for example, 200 mV to 450 mV). At this time, when the electromotive force of the oxygen concentration measuring cell is 200 mV, the oxygen partial pressure is 10 −4 a.
In the case of tm and 450 mV, the oxygen partial pressure is 10 -9 atm.
【００２５】第２酸素ポンピングセルに印加する電圧
は、第２空隙部の温度や第２空隙部内に触媒機能物質が
存在する場合にはその種類、第２酸素ポンピングセルの
電極の種類などによって変化するが、ＣＯ2やＨ2Ｏが分
解しない電圧、たとえば温度が７００℃で電極が多孔質
ロジウム（Ｒｈ）であるとき、安定して酸素のみを汲み
出すことができるように３００〜８００ｍＶとするのが
好ましい。The voltage applied to the second oxygen pumping cell varies depending on the temperature of the second void, the type of the catalytic function substance in the second void if it exists, the type of the electrode of the second oxygen pumping cell, and the like. However, when the voltage is such that CO 2 or H 2 O is not decomposed, for example, when the temperature is 700 ° C. and the electrode is porous rhodium (Rh), the voltage is set to 300 to 800 mV so that only oxygen can be stably pumped out. Is preferred.
【００２６】本発明の可燃物質濃度の検出方法は、従来
の検出方法と比べて酸素濃度測定セルの電極と他の酸素
セルの電極と間の電流リークが僅かであることによっ
て、好ましくは絶縁膜又は絶縁層で電極間が絶縁されて
いて電極間で電流リークがないことによって、酸素濃度
測定セルの測定精度が高い。酸素濃度測定セルの測定精
度が高いことによって、第１空隙部内の当初の酸素濃度
を可燃物質が燃焼分解しない一定の低濃度に精度よく制
御でき、第１酸素ポンピングセルにより外部から汲み込
まれた酸素を含む被測定ガスを第２拡散通路から第２空
隙部に送って被測定ガス中の酸素を第２酸素ポンピング
セルで汲み出すことにより、第１酸素ポンピングセルま
たは第２酸素ポンピングセルに流れる電流値から可燃物
質の燃焼分解に使われた酸素量を介して可燃物質濃度を
精度よく検出できる。この検出方法で得られる検出値
は、被測定ガス中の酸素を除く介在ガスの濃度によって
変動しない。また、被測定ガス中の酸素濃度による変動
はあまり大きくない。The method for detecting the concentration of combustible substances according to the present invention is preferable because the current leak between the electrode of the oxygen concentration measuring cell and the electrode of another oxygen cell is small as compared with the conventional detecting method. Alternatively, since the electrodes are insulated by the insulating layer and there is no current leak between the electrodes, the measurement accuracy of the oxygen concentration measurement cell is high. Due to the high measurement accuracy of the oxygen concentration measurement cell, the initial oxygen concentration in the first gap can be accurately controlled to a constant low concentration at which the combustible substance does not burn and decompose, and is pumped from the outside by the first oxygen pumping cell. The gas to be measured containing oxygen is sent from the second diffusion passage to the second gap, and the oxygen in the gas to be measured is pumped out by the second oxygen pumping cell, so that the gas flows into the first oxygen pumping cell or the second oxygen pumping cell. The concentration of the combustible substance can be accurately detected from the current value through the amount of oxygen used for the combustion decomposition of the combustible substance. The detection value obtained by this detection method does not vary depending on the concentration of the intervening gas other than oxygen in the gas to be measured. Further, the fluctuation due to the oxygen concentration in the gas to be measured is not so large.
【００２７】本発明の他の好ましい可燃物質濃度の検出
方法は、被測定ガス中の酸素濃度が可燃物質濃度の検出
値に及ぼす影響を、あらかじめ酸素濃度と可燃物質濃度
が異なり、かつ既知である標準ガスを用いて測定したデ
ータに基いて補正する。これによって被測定ガス中に含
まれる酸素濃度による検出値の変動を補正することがで
き、可燃物質濃度の検出精度を一層向上させることがで
きる。In another preferred method for detecting the concentration of a combustible substance of the present invention, the effect of the oxygen concentration in the gas to be measured on the detected value of the concentration of the combustible substance is known in advance so that the oxygen concentration and the combustible substance concentration are different. Correct based on data measured using standard gas. This makes it possible to correct the fluctuation of the detection value due to the concentration of oxygen contained in the gas to be measured, and to further improve the detection accuracy of the concentration of the combustible substance.
【００２８】本発明の他の好ましい可燃物質濃度の検出
方法は、前記データが、前記標準ガスを用いて酸素濃度
測定セルで第１空隙部内の酸素濃度を監視しつつ第１酸
素ポンピングセルで第１空隙部内の酸素濃度を可燃物質
が燃焼分解されない程度の低濃度に一定に保つときの被
測定ガス中の酸素濃度（％）と第１酸素ポンピングセル
のポンプ電流Ｉｐ1（μＡ）との関係、可燃物質濃度が
ゼロのときの酸素濃度（％）と第２空隙部から酸素を汲
み出す第２酸素ポンピングセルのポンプ電流Ｉｐ2 O（μ
Ａ）との関係、及び測定対象とする被測定ガスと同レベ
ルの酸素濃度を有し、異なる可燃物質濃度を有する標準
ガスについて求めた可燃物質濃度（ｐｐｍ）と第２酸素
ポンピングセルのポンプ電流Ｉｐ2（μＡ）との関係で
ある。このデータは、検出器の仕様やその製造上のばら
つき、たとえば検出器の設定温度、第１拡散通路や第２
拡散通路の通気性とその比、第１空隙部と第２空隙部の
容積とその比などによって変わるので、各検出器につい
てあらかじめ測定データを求めておくことが好ましい。According to another preferred method of detecting the concentration of combustible material of the present invention, the data is obtained by monitoring the oxygen concentration in the first void by using the standard gas and measuring the oxygen concentration in the first gap by using the standard gas. ( 1 ) Relationship between oxygen concentration (%) in the gas to be measured and pump current Ip 1 (μA) of the first oxygen pumping cell when the oxygen concentration in the gap is kept constant at a low level such that combustible substances are not decomposed by combustion. The oxygen concentration (%) when the combustible substance concentration is zero, and the pump current Ip 2 O (μ) of the second oxygen pumping cell for pumping oxygen from the second gap.
A), and the combustible substance concentration (ppm) obtained for a standard gas having the same level of oxygen concentration as the measured gas to be measured and having a different combustible substance concentration, and the pump current of the second oxygen pumping cell. This is the relationship with Ip 2 (μA). This data is based on the specifications of the detector and its manufacturing variations, such as the set temperature of the detector, the first diffusion path and the second diffusion path.
It depends on the permeability and the ratio of the diffusion passage, the volume of the first gap and the second gap, the ratio thereof, and the like. Therefore, it is preferable to obtain measurement data in advance for each detector.
【００２９】本発明の他の好ましい可燃物質濃度の検出
方法は、被測定ガス中の酸素濃度が変化しても、可燃物
質濃度（ｐｐｍ）とポンプ電流Ｉｐ2（μＡ）との間に
所定の函数関係（例えば直線関係）があると過程し、あ
らかじめマイクロコンピュータのメモリーに蓄積した前
記データに基きマイクロコンピュータで演算して補正し
た可燃物質濃度を求め、ディスプレイに表示又は記録計
に出力する。検出値の補正演算を検出器に付設したマイ
クロコンピュータによって行なえば、補正された精度の
よい検出値をオンタイムで得ることができ、得られた検
出値を表示あるいは記録できる他、内燃機関などの燃焼
装置の制御部にこの検出値をフィードバックして燃焼装
置の運転状態の制御に使用できる。Another preferred method for detecting a combustible substance concentration according to the present invention is that, even when the oxygen concentration in the gas to be measured changes, a predetermined value is set between the combustible substance concentration (ppm) and the pump current Ip 2 (μA). When there is a function relationship (for example, a linear relationship), the microcomputer calculates the corrected combustible substance concentration based on the data stored in the memory of the microcomputer in advance, and displays it on a display or outputs it to a recorder. If the correction calculation of the detected value is performed by a microcomputer attached to the detector, a corrected and accurate detected value can be obtained on-time, and the obtained detected value can be displayed or recorded. The detected value is fed back to the control unit of the combustion device and can be used for controlling the operation state of the combustion device.
【００３０】本発明の自動車排ガス触媒装置のモニタリ
ング方法は、触媒装置の下流側に取り付けられた前記請
求項１〜１５のいずれかに記載の可燃物質濃度検出器
と、前記触媒装置の上流側に取り付けた酸素濃度検出器
とを備え、前記可燃物質濃度検出器により検出される可
燃物質濃度と前記酸素濃度検出器により検出される酸素
濃度とから前記触媒装置の酸素貯蔵能力をモニタリング
することを特徴とする。このモニタリング方法では、従
来の２本のＥＧＯセンサまたはＵＥＧＯセンサを使用す
る方法と異なり、被測定ガス中の可燃物質に対する感度
の高い検出器を使用しており、触媒装置のモニタリング
の精度も高い。A method for monitoring a catalytic converter for automobile exhaust gas according to the present invention, comprising: a detector for detecting the concentration of a combustible substance according to any one of claims 1 to 15 attached downstream of the catalytic converter; An oxygen concentration detector attached, wherein the oxygen storage capacity of the catalyst device is monitored from the combustible substance concentration detected by the combustible substance concentration detector and the oxygen concentration detected by the oxygen concentration detector. And In this monitoring method, unlike the conventional method using two EGO sensors or UEGO sensors, a detector having high sensitivity to combustible substances in the gas to be measured is used, and the monitoring accuracy of the catalyst device is high.
【００３１】なお、本発明の可燃物質濃度検出器は、第
２酸素ポンピングセルの動作を停止させれば、通常の全
領域空燃比センサ（ＵＥＧＯセンサ）としても使用する
ことができる。従って、測定するタイミングをずらすこ
とにより、空燃比（Ａ／Ｆ）または酸素濃度と可燃物質
濃度の両者を一つの検出器で測定することも可能であ
る。この場合、そのようにして測定した酸素濃度に基づ
いて演算処理により酸素濃度補正を行ない、より正確な
可燃物質濃度を測定することもできる。Incidentally, the combustible substance concentration detector of the present invention can be used also as a normal whole area air-fuel ratio sensor (UEGO sensor) if the operation of the second oxygen pumping cell is stopped. Therefore, by shifting the measurement timing, it is possible to measure both the air-fuel ratio (A / F) or the oxygen concentration and the combustible substance concentration with one detector. In this case, the oxygen concentration can be corrected by arithmetic processing based on the oxygen concentration measured in this way, and a more accurate combustible substance concentration can be measured.
【００３２】さらに、第１酸素ポンピングセルの動作を
一時的に変更して、第１空隙部内の酸素を外部へ汲み出
すように作動させることにより、上記の空燃比、可燃物
質濃度とともに、窒素酸化物（ＮＯｘ）の濃度も併せて
測定することが可能である。さらに、各酸素ポンピング
セルの動作設定条件を変えることにより、排ガス中に含
まれるＣＯ2やＨ2Ｏの濃度も測定することができる。Further, by temporarily changing the operation of the first oxygen pumping cell and operating the first oxygen pumping cell so as to pump oxygen in the first gap to the outside, the above-described air-fuel ratio and combustible substance concentration, and nitrogen oxide The concentration of the substance (NOx) can also be measured. Further, by changing the operation setting conditions of each oxygen pumping cell, the concentrations of CO 2 and H 2 O contained in the exhaust gas can be measured.
【００３３】[0033]
【実施例】以下、本発明を実施例の図面に基いて具体的
に説明するが、本発明は以下の実施例に限定されない。 ［実施例１］図１は、本発明の一実施例である可燃物質
濃度検出器の先端部分の縦断面図である。同図におい
て、１は第１拡散通路、２は第１空隙部、３は第２拡散
通路、４は第２空隙部、５−１、５−２、５−３、５−
４、５−５及び５−６は薄板状ジルコニアの固体電解質
層、６は第１酸素ポンピングセル、６−ａ及び６−ｂは
第１酸素ポンピングセルの多孔質電極、７は酸素濃度測
定セル、７−ａ及び７−ｂは酸素濃度測定セルの多孔質
電極、８は第２酸素ポンピングセル、８−ａ及び８−ｂ
は第２酸素ポンピングセルの多孔質電極、９−ａ及び９
−ｂは加熱ヒータである。DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail with reference to the drawings of embodiments, but the present invention is not limited to the following embodiments. [Embodiment 1] FIG. 1 is a longitudinal sectional view of a tip portion of a combustible substance concentration detector according to an embodiment of the present invention. In the figure, 1 is a first diffusion path, 2 is a first gap, 3 is a second diffusion path, 4 is a second gap, 5-1, 5-2, 5-3, 5-
4, 5-5 and 5-6 are thin zirconia solid electrolyte layers, 6 is a first oxygen pumping cell, 6-a and 6-b are porous electrodes of the first oxygen pumping cell, and 7 is an oxygen concentration measuring cell. , 7-a and 7-b are porous electrodes of an oxygen concentration measurement cell, 8 is a second oxygen pumping cell, 8-a and 8-b
Are the porous electrodes of the second oxygen pumping cell, 9-a and 9
-B is a heater.
【００３４】上下に設けられた加熱ヒータ９−ａ、９−
ｂと第１、第２酸素ポンピングセルとの間には、それぞ
れ外気に連通する通路３１が設けられ、各酸素ポンピン
グセルから抜き取った、もしくは外気から汲み入れる酸
素ガスを供給または排出できるようになっている。加熱
ヒータ９−ａ、９−ｂの基部はセメント等の接着層（図
示省略）で各酸素ポンピングセルの基部に装着される。
なお、酸素濃度測定セル７の第１空隙部に対向する側の
電極は内部基準電極をなし、その多孔質電極と多孔質リ
ード部を介して外気に連通される。Heaters 9-a, 9-
A passage 31 communicating with the outside air is provided between b and the first and second oxygen pumping cells, so that oxygen gas extracted from each oxygen pumping cell or pumped from the outside air can be supplied or discharged. ing. The bases of the heaters 9-a and 9-b are attached to the base of each oxygen pumping cell with an adhesive layer (not shown) such as cement.
The electrode of the oxygen concentration measuring cell 7 on the side facing the first void forms an internal reference electrode, and is communicated with the outside air via the porous electrode and the porous lead.
【００３５】図１に示された可燃物質濃度検出器では、
酸素濃度測定セル７と第２酸素ポンピングセル８が異な
る固体電解質層５−３及び５−６にそれぞれ設けられて
いる。本実施例の可燃物質濃度検出器では、酸素セルが
いずれも異なる固体電解質層に設けられているので、各
酸素セルの電極間の電流リークが僅かとなり、酸素濃度
測定セル７によって測定される酸素濃度の精度が高い。
この酸素濃度測定セル７で第１空隙部２中の酸素濃度を
監視しつつ第１空隙部２から第１酸素ポンピングセル６
で酸素を抜き取り、第１空隙部２内の酸素濃度を可燃物
質が燃焼分解しない程度の低い酸素濃度、たとえば１０
-4〜１０-9ａｔｍに制御する。本実施例では多孔質電極
７−ａ及び７−ｂ間に発生する起電力を２００ｍＶ〜４
５０ｍＶの範囲内の一定の値となるように制御してい
る。In the combustible substance concentration detector shown in FIG.
An oxygen concentration measurement cell 7 and a second oxygen pumping cell 8 are provided in different solid electrolyte layers 5-3 and 5-6, respectively. In the combustible substance concentration detector of this embodiment, since the oxygen cells are all provided in different solid electrolyte layers, the current leak between the electrodes of each oxygen cell becomes small, and the oxygen concentration measured by the oxygen concentration measurement cell 7 is reduced. High concentration accuracy.
The oxygen concentration in the first gap 2 is monitored by the oxygen concentration measuring cell 7 while the first oxygen pumping cell 6
To remove oxygen, and reduce the oxygen concentration in the first void portion 2 to a low oxygen concentration such as 10
Control at -4 to 10 -9 atm. In this embodiment, the electromotive force generated between the porous electrodes 7-a and 7-b is 200 mV to 4 mV.
Control is performed so as to be a constant value within a range of 50 mV.
【００３６】次いで酸素濃度の低いこの被測定ガス中に
含まれる可燃物質が触媒機能を有する電極上で燃焼され
るが、その際に第１空隙部２内に僅かに存在する酸素が
消費される。この第１空隙部２内の酸素濃度の変化が酸
素濃度測定セル７で検知され、これを所定の酸素濃度に
維持すべく第１酸素ポンピングセル６により外部より酸
素が汲み入れられる。また、第１空隙部２内の被測定ガ
スは、第２拡散通路３を介して第２空隙部４に送られ、
ここで第２酸素ポンピングセル８により酸素のほとんど
を外部に汲み出す。本実施例では、第２酸素ポンプセル
の多孔質電極８−ａ及び８−ｂ間に４５０ｍＶの定電圧
が印加されている。この印加電圧を微妙に調節すること
によって、可燃物質濃度検出器個体間の出力のばらつき
を調節することができる。Next, a combustible substance contained in the gas to be measured having a low oxygen concentration is burned on the electrode having a catalytic function. At this time, oxygen slightly existing in the first gap 2 is consumed. . The change in the oxygen concentration in the first void portion 2 is detected by the oxygen concentration measuring cell 7, and oxygen is pumped in from the outside by the first oxygen pumping cell 6 to maintain the oxygen concentration at a predetermined oxygen concentration. The gas to be measured in the first gap 2 is sent to the second gap 4 via the second diffusion passage 3,
Here, most of the oxygen is pumped to the outside by the second oxygen pumping cell 8. In this embodiment, a constant voltage of 450 mV is applied between the porous electrodes 8-a and 8-b of the second oxygen pump cell. By finely adjusting the applied voltage, it is possible to adjust the variation in output among the individual combustible substance concentration detectors.
【００３７】第２酸素ポンピングセルによって汲み出さ
れる酸素量は、可燃物質の燃焼反応で消費された酸素
量、すなわち、第１酸素ポンピングセル６により汲み入
れられた酸素量に相当するものとなっている。従って、
第２酸素ポンピングセル８により汲み出される酸素量
は、同セルを流れる電流値から測定することができ、求
めた酸素量から被測定ガス中に含まれていた可燃物質の
濃度を算出することができる。The amount of oxygen pumped by the second oxygen pumping cell corresponds to the amount of oxygen consumed by the combustion reaction of the combustible material, that is, the amount of oxygen pumped by the first oxygen pumping cell 6. I have. Therefore,
The amount of oxygen pumped by the second oxygen pumping cell 8 can be measured from the value of the current flowing through the cell, and the concentration of the combustible substance contained in the gas to be measured can be calculated from the obtained amount of oxygen. it can.
【００３８】この可燃物質濃度の測定方法では、被測定
ガスと第１酸素ポンピングセル６と第２酸素ポンピング
セル８の温度、第１拡散通路１及び第２拡散通路３のガ
ス拡散抵抗、第１空隙部２の設定酸素濃度、第２酸素ポ
ンピングセル３の設定電圧などによって第２酸素ポンピ
ングセル８に流れる電流値が変化するので、あらかじめ
ガス濃度が既知の標準ガスを用いて較正しておく。この
可燃物質濃度検出器の寸法は、たとえば高さ（固定電解
質層に垂直な方向）が１．７ｍｍ、幅３．５ｍｍ、長さ
７ｍｍである。In this method of measuring the combustible substance concentration, the gas to be measured, the temperature of the first oxygen pumping cell 6 and the temperature of the second oxygen pumping cell 8, the gas diffusion resistance of the first diffusion passage 1 and the second diffusion passage 3, the first Since the value of the current flowing through the second oxygen pumping cell 8 changes depending on the set oxygen concentration in the gap 2, the set voltage of the second oxygen pumping cell 3, and the like, calibration is performed using a standard gas whose gas concentration is known in advance. The dimensions of the combustible substance concentration detector are, for example, a height (in a direction perpendicular to the fixed electrolyte layer) of 1.7 mm, a width of 3.5 mm, and a length of 7 mm.
【００３９】［実施例２］図２は、実施例２に係る可燃
物質濃度検出器の平面図である。この検出器の寸法は、
高さ（固体電解質層に垂直な方向）１．５ｍｍ、幅３．
５ｍｍ、長さ５ｍｍである。また、図３は図２における
Ｂ−Ｂ’縦断面図である。第１拡散通路１は、検出器の
先端側でなく検出器の両側にあり、第１空隙部２と第２
空隙部４が上下方向に互いに概ね重なり合って配置され
ている。実施例１と異なる点は、固体電解質層５−１、
５−２、５−３、５−４、５−５及び５−６の各相互間
にそれぞれ絶縁膜１１−１、１１−２、１１−３、１１
−４及び１１−５が配置されており、各酸素セルの電極
は互いに絶縁されている点である。なお、図２では、実
施例１と同じ機能を有する部分には同じ符号を付して説
明を省略した（以下同じ）。Second Embodiment FIG. 2 is a plan view of a combustible substance concentration detector according to a second embodiment. The dimensions of this detector are
2. Height (in the direction perpendicular to the solid electrolyte layer) 1.5 mm, width 3.
5 mm and length 5 mm. FIG. 3 is a vertical sectional view taken along the line BB 'in FIG. The first diffusion passage 1 is not on the tip side of the detector but on both sides of the detector.
The gaps 4 are arranged so as to substantially overlap each other in the vertical direction. The difference from the first embodiment is that the solid electrolyte layer 5-1,
Insulating films 11-1, 11-2, 11-3, and 11 are respectively disposed between 5-2, 5-3, 5-4, 5-5, and 5-6.
-4 and 11-5 are arranged, and the electrode of each oxygen cell is insulated from each other. In FIG. 2, portions having the same functions as those in the first embodiment are denoted by the same reference numerals, and description thereof is omitted (the same applies hereinafter).
【００４０】この実施例２では、厚さ２０〜３０μｍの
高純度アルミナの絶縁膜１１−１、１１−２、１１−
３、１１−４及び１１−５が固体電解質層の間に配置さ
れていることによって酸素濃度測定セル７の電極７−
ａ、７−ｂと、第１酸素ポンピングセル６及び第２酸素
ポンピングセル８の電極６−ａ、６−ｂ及び８−ａ、８
−ｂとの間のリーク電流を完全に防止している。そのた
め、酸素濃度測定セル７の測定精度が高く、第１空隙部
２内の酸素を一定の低濃度に安定して保持でき、可燃物
質濃度が低い場合であっても高い検出精度で可燃物質の
濃度を得ることができる。なお、第２空隙部４には多孔
質材料を充填してもよい。In the second embodiment, the insulating films 11-1, 11-2, 11- made of high-purity alumina having a thickness of 20 to 30 μm are used.
3, 11-4 and 11-5 are arranged between the solid electrolyte layers, so that the electrodes 7-
a, 7-b and the electrodes 6-a, 6-b and 8-a, 8 of the first oxygen pumping cell 6 and the second oxygen pumping cell 8.
-B is completely prevented. Therefore, the measurement accuracy of the oxygen concentration measurement cell 7 is high, the oxygen in the first gap 2 can be stably maintained at a constant low concentration, and even when the concentration of the combustible substance is low, the detection of the combustible substance is performed with high detection accuracy. A concentration can be obtained. The second gap 4 may be filled with a porous material.
【００４１】図３にはさらに、第１酸素ポンピングセル
６の電源部１５と電流計１６、酸素濃度測定セル７のポ
テンショメータ１７、第２酸素ポンピングセル８の電源
部１９と電流計１８及び記録計２１を備えたマイクロコ
ンピュータ２０が付設されている。この検出器の酸素濃
度測定セル７の基準酸素濃度は、電極７−ｂとそのリー
ド線が多孔質であることによって外部の空気に所定の拡
散抵抗を介して連通されている。また、酸素濃度測定セ
ル７に一定の微小電流を流す構成にすれば、電極７−ｂ
を自己生成基準極として使用できる。この自己生成基準
極の利点は基準とする酸素濃度が空気中の酸素濃度の変
化に影響されにくいことである。FIG. 3 further shows a power supply 15 and an ammeter 16 of the first oxygen pumping cell 6, a potentiometer 17 of the oxygen concentration measuring cell 7, a power supply 19 and an ammeter 18 of the second oxygen pumping cell 8, and a recorder. A microcomputer 20 including 21 is provided. The reference oxygen concentration of the oxygen concentration measuring cell 7 of this detector is communicated to the outside air via a predetermined diffusion resistance because the electrode 7-b and its lead wire are porous. In addition, if a constant minute current is applied to the oxygen concentration measuring cell 7, the electrode 7-b
Can be used as a self-generated reference pole. The advantage of this self-generated reference electrode is that the reference oxygen concentration is less susceptible to changes in the oxygen concentration in the air.
【００４２】［実施例３］図４は、本発明の可燃物質濃
度検出器を製造するときのレイアウトの一例を示す斜視
図である。この場合、酸素濃度測定セル７も微少な一定
電流を流せば電極７−ｂを自己生成基準極として使用可
能である。[Embodiment 3] FIG. 4 is a perspective view showing an example of a layout for manufacturing a combustible substance concentration detector of the present invention. In this case, the electrode 7-b can be used as a self-generated reference electrode if a small constant current is applied to the oxygen concentration measurement cell 7 as well.
【００４３】図５は図２や図４の可燃物質濃度検出器に
積層して使用する加熱ヒータであり、この加熱ヒータ２
４は固体電解質層５−７上にスクリーン印刷されたアル
ミナと白金の複合材料からなる発熱部２２と、白金のリ
ード線２３からなる。この加熱ヒータは、たとえば図２
に示された検出器の下方に積層され、一体化される。こ
の発熱部２２は第１空隙部２及び第２空隙部４と固体電
解質層に垂直方向に投影したとき互いに概ね重なり合っ
ている。この例では、加熱ヒータ２４は高純度アルミナ
の絶縁膜１１−６に挟まれており、第２酸素ポンピング
セルの電極とは絶縁されている。FIG. 5 shows a heater laminated on the combustible substance concentration detector shown in FIGS.
Reference numeral 4 denotes a heating section 22 made of a composite material of alumina and platinum screen-printed on the solid electrolyte layer 5-7, and a lead wire 23 of platinum. This heater is shown in FIG.
Are stacked and integrated below the detector shown in FIG. The heat generating portion 22 substantially overlaps with the first gap portion 2 and the second gap portion 4 when projected onto the solid electrolyte layer in the vertical direction. In this example, the heater 24 is sandwiched between insulating films 11-6 of high-purity alumina, and is insulated from the electrodes of the second oxygen pumping cell.
【００４４】［試験例１］実施例１の可燃物質濃度検出
器（図１の構成のもの）を使用し、モデルガス中での各
種可燃物質に対する応答性を調べた結果について以下に
説明する。ＣＯ2を１０％、Ｏ2を５０ｐｐｍ含むＮ2ガ
スを基準ガスとして用い、これにＣＨ4、Ｃ3Ｈ6、Ｃ
Ｏ、ＮＯの各濃度を０ｐｐｍ〜５００ｐｐｍの間で変化
させたものをモデルガスとして用意した。加熱ヒータを
作動させて検出器の温度を７００℃とし、酸素濃度測定
セルの起電力Ｖｓを４５０ｍＶ、第２酸素ポンピングセ
ルの印加電圧を４５０ｍＶにそれぞれ設定した状態で、
上記モデルガスを毎分１２リットルの流量で流しながら
第２ポンピングセルに流れるポンプ電流を測定した。図
６は、第２酸素ポンピングセルに流れるポンプ電流Ｉｐ
2（μＡ）と被測定ガス中の上記各可燃物質の濃度（ｐ
ｐｍ）との関係を示すグラフである。なお、比較例とし
て、従来のＵＥＧＯセンサによる出力結果を図７に示し
た。[Test Example 1] The results of examining the responsiveness to various combustible substances in a model gas using the combustible substance concentration detector of Embodiment 1 (having the configuration shown in FIG. 1) will be described below. N 2 gas containing 10% of CO 2 and 50 ppm of O 2 was used as a reference gas, and CH 4 , C 3 H 6 , C
What changed each concentration of O and NO between 0 ppm and 500 ppm was prepared as a model gas. The heater was operated to set the temperature of the detector at 700 ° C., the electromotive force Vs of the oxygen concentration measurement cell was set at 450 mV, and the applied voltage of the second oxygen pumping cell was set at 450 mV.
The pump current flowing through the second pumping cell was measured while flowing the model gas at a flow rate of 12 liters per minute. FIG. 6 shows the pump current Ip flowing through the second oxygen pumping cell.
2 (μA) and the concentration (p
6 is a graph showing the relationship with the pm). As a comparative example, FIG. 7 shows an output result by a conventional UEGO sensor.
【００４５】炭化水素であるＣＨ4、Ｃ3Ｈ6に対して
は、濃度の増加に対して第２酸素ポンピングセルのポン
プ電流が増加する傾向を示した。ＣＨ4とＣ3Ｈ6とを比
較すると、分子量の小さいＣＨ4に対する出力の方が大
きい。被測定ガス中のＣＯ、ＮＯに対してはほとんどポ
ンプ電流値に変化は見られず、これらのガスが混在して
いても可燃物質の濃度測定には影響しないことが確認さ
れた。特にＮＯガスの影響はほとんど受けていないもの
であった。一方、ＵＥＧＯセンサの場合は、ＣＨ4やＣ3
Ｈ6の濃度に対するポンプ電流の変化が極めて少なく、
本実施例の検出器に比べて感度の低いことが確かめられ
た。For hydrocarbons CH 4 and C 3 H 6 , the pump current of the second oxygen pumping cell tended to increase as the concentration increased. When CH 4 and C 3 H 6 are compared, the output for CH 4 having a small molecular weight is larger. There was almost no change in the pump current value for CO and NO in the gas to be measured, and it was confirmed that the presence of these gases did not affect the measurement of the concentration of combustible substances. In particular, it was hardly affected by NO gas. On the other hand, in the case of the UEGO sensor, CH 4 or C 3
The change of the pump current with respect to the concentration of H 6 is extremely small,
It was confirmed that the sensitivity was lower than that of the detector of this example.
【００４６】［試験例２］実施例１の可燃物質濃度検出
器（図１の構成のもの）を使用し、第２酸素ポンピング
セルへの印加電圧の影響を調べた結果について以下に説
明する。基準ガスは前述の試験例１と同じものを用い、
これにＣＨ4の濃度を０ｐｐｍ〜５００ｐｐｍの間で変
化させたものをモデルガスとして用意した。加熱ヒータ
を作動させて検出器の温度を７００℃とし、酸素濃度測
定セルの起電力Ｖｓを４５０ｍＶに設定した状態で上記
モデルガスを毎分１２リットルの流量で流し、第２酸素
ポンピングセルの印加電圧を２５０ｍＶ、４５０ｍＶ、
６５０ｍＶにそれぞれ変化させた場合における第２酸素
ポンピングセルに流れるポンプ電流を測定した。[Test Example 2] The result of examining the effect of the voltage applied to the second oxygen pumping cell using the combustible substance concentration detector (of the configuration shown in FIG. 1) of Example 1 will be described below. The same reference gas as in Test Example 1 was used.
A gas in which the concentration of CH 4 was changed between 0 ppm and 500 ppm was prepared as a model gas. The model gas is flowed at a flow rate of 12 liters per minute while the heater is operated to set the temperature of the detector at 700 ° C. and the electromotive force Vs of the oxygen concentration measurement cell at 450 mV, and the second oxygen pumping cell is applied. Voltage 250mV, 450mV,
The pump current flowing through the second oxygen pumping cell when each was changed to 650 mV was measured.
【００４７】図８は、第２酸素ポンピングセルに流れる
ポンプ電流Ｉｐ2（μＡ）と被測定ガス中のＣＨ4の濃度
（ｐｐｍ）との関係を示すグラフである。印加電圧を増
加させるとＣＨ4に対する感度が上昇する。この現象を
利用すると、検出器個体間の感度のばらつきを第２酸素
ポンピングセルへの印加電圧によって調整することがで
きる。FIG. 8 is a graph showing the relationship between the pump current Ip 2 (μA) flowing through the second oxygen pumping cell and the concentration (ppm) of CH 4 in the gas to be measured. Increasing the applied voltage sensitivity increases for CH 4. By utilizing this phenomenon, it is possible to adjust the variation in sensitivity among the individual detectors by applying a voltage to the second oxygen pumping cell.
【００４８】［試験例３］実施例１の可燃物質濃度検出
器（図１の構成のもの）を使用し、第１酸素ポンピング
セル及び第２酸素ポンピングセルのそれぞれのポンプ電
流値を比較した結果について以下に説明する。図９は、
前述の試験例１と同じ条件のもとで可燃物質濃度を測定
した場合の、各ポンプ電流値Ｉｐ1とＩｐ2との相関関係
を示したものである。両者は非常によい相関性を示して
おり、いずれのポンプ電流値を用いても可燃物質濃度が
検出可能であることがわかる。[Test Example 3] The results of comparing the pump current values of the first oxygen pumping cell and the second oxygen pumping cell using the combustible substance concentration detector of Example 1 (having the configuration shown in FIG. 1). Will be described below. FIG.
FIG. 9 shows a correlation between each pump current value Ip 1 and Ip 2 when the flammable substance concentration is measured under the same conditions as in Test Example 1 described above. Both show a very good correlation, and it can be seen that the combustible substance concentration can be detected using any of the pump current values.
【００４９】［試験例４］実施例１の可燃物質濃度検出
器（図１の構成のもの）を使用し、第２酸素ポンピング
セルのポンプ電流値に及ぼす酸素濃度の影響を調べた結
果について以下に説明する。図１０は、基準ガスの酸素
濃度以外は前述の試験例１と同じ条件で種々の濃度の可
燃物質（ＣＨ4）に対するポンプ電流値Ｉｐ2を測定し、
基準ガス中の酸素濃度による変化をプロットしたもので
ある。本試験条件のもとでは、酸素濃度が高くなるほど
低濃度のＣＨ4に対する応答性が低下し、酸素濃度が５
００ｐｐｍより高くなると、３００ｐｐｍ以下のＣＨ4
に対する感度が得られなくなることが確認された。すな
わち、可燃物質濃度の検出においては、第１空隙部内の
酸素濃度の制御が重要であるが、本発明の検出器を用い
て検出することにより、高精度に可燃物質の濃度が測定
できることがわかった。Test Example 4 The effect of the oxygen concentration on the pump current value of the second oxygen pumping cell using the combustible substance concentration detector of Example 1 (having the configuration shown in FIG. 1) was examined. Will be described. FIG. 10 shows measurement of the pump current value Ip 2 for various concentrations of combustible substances (CH 4 ) under the same conditions as in Test Example 1 except for the oxygen concentration of the reference gas.
It is a plot of a change due to an oxygen concentration in a reference gas. Under this test condition, as the oxygen concentration becomes higher responsiveness to low concentrations of CH 4 decreases, the oxygen concentration is 5
If it is higher than 00 ppm, CH 4 of 300 ppm or less
It was confirmed that the sensitivity to was no longer obtained. That is, in the detection of the combustible substance concentration, it is important to control the oxygen concentration in the first void portion. However, it can be understood that the detection of the combustible substance concentration can be performed with high accuracy by using the detector of the present invention. Was.
【００５０】［試験例５］本発明の可燃物質濃度検出器
を使用し、実際のガソリン内燃機関の排気系に取り付け
て評価を行なった結果について説明する。図１１は実機
での評価システムの構成を示す模式図である。実施例１
の可燃物質濃度検出器を、ガソリン内燃機関（エンジ
ン）の排ガス管の触媒下流側に設けた穴から挿入し、固
定した。エンジンの運転条件は、排気量：１．５リット
ル、車速：６０ｋｍ／ｈ（２速ギヤ）、エンジン回転
数：３５００ｒｐｍ、空燃比（Ａ／Ｆ）：１４．６、排
ガス温度：５００℃で行なった。この運転条件を一定に
保ったまま、マスフローコントローラよりＣＨ4または
Ｃ3Ｈ6を所定の濃度となるように添加した。また、第２
酸素ポンピングセルのポンプ電流を電圧に変換して出力
するために、図１２に示すような回路を使用した。[Test Example 5] The result of evaluation using the flammable substance concentration detector of the present invention attached to an actual exhaust system of a gasoline internal combustion engine will be described. FIG. 11 is a schematic diagram showing a configuration of an evaluation system in a real machine. Example 1
Was inserted through a hole provided in the exhaust gas pipe of a gasoline internal combustion engine (engine) on the downstream side of the catalyst, and fixed. The engine was operated under the following conditions: displacement: 1.5 liters, vehicle speed: 60 km / h (second gear), engine speed: 3500 rpm, air-fuel ratio (A / F): 14.6, exhaust gas temperature: 500 ° C. Was. With these operating conditions kept constant, CH 4 or C 3 H 6 was added from a mass flow controller to a predetermined concentration. Also, the second
In order to convert the pump current of the oxygen pumping cell into a voltage and output the voltage, a circuit as shown in FIG. 12 was used.
【００５１】図１３は、上記の評価システムを用いて、
ＣＨ4を添加した場合の検出器の出力を示したものであ
る。ＣＨ4の濃度を４４．４ｐｐｍ、２２９ｐｐｍ、４
１１ｐｐｍ、５９２ｐｐｍと変化させると、検出器の出
力（ポンプ電流Ｉｐ2）も、平均値で、１５．７μＡ、
２３．７μＡ、７１．５μＡ、１７０．０μＡと変化
し、実機においても十分に応答性を有することが確かめ
られた。また、この検出器のポンプ電流の出力の平均値
と可燃物質の濃度との関係をプロットしたものを図１４
に示す。ＣＨ4及びＣ3Ｈ6のいずれも濃度の増加に対し
て出力の平均値が増加しており、ＣＨ4に対する出力の
方がＣ3Ｈ6に対する出力よりも大きい。FIG. 13 shows an example using the above evaluation system.
3 shows the output of the detector when CH 4 is added. The concentration of CH 4 was 44.4 ppm, 229 ppm, 4
When it is changed to 11 ppm and 592 ppm, the output of the detector (pump current Ip 2 ) is also 15.7 μA on average,
It changed to 23.7 μA, 71.5 μA, and 170.0 μA, and it was confirmed that the device had sufficient responsiveness even in an actual machine. FIG. 14 is a graph plotting the relationship between the average value of the pump current output of the detector and the concentration of combustible substances.
Shown in In both CH 4 and C 3 H 6 , the average value of the output increases as the concentration increases, and the output for CH 4 is larger than the output for C 3 H 6 .
【００５２】また、この検出器では、検出器を固体電解
質層に垂直な方向に投影したとき、第１空隙部、第２空
隙部及び発熱部が互いに概ね重なり合う位置にあるの
で、排ガス管の壁に設けた穴から検出器の測定部を排ガ
ス管内に挿入して排ガス管内を流れる被測定ガス中の可
燃物質濃度を検出するとき、第１空隙部、第２空隙部及
び酸素濃度測定セルが排ガス管の壁からほぼ等距離にあ
り、排ガス管内の温度分布に起因する温度差がほとんど
発生しないことが分かった。Further, in this detector, when the detector is projected in a direction perpendicular to the solid electrolyte layer, the first gap, the second gap, and the heating section are located at positions substantially overlapping each other. When the measuring part of the detector is inserted into the exhaust gas pipe through the hole provided in the exhaust gas pipe and the concentration of the combustible substance in the gas to be measured flowing in the exhaust gas pipe is detected, the first void, the second void, and the oxygen concentration measuring cell It was found that there was almost no temperature difference due to the temperature distribution in the exhaust gas pipe, which was almost equidistant from the pipe wall.
【００５３】さらに、第１空隙部が細長くない形状とさ
れているので、第１空隙部内における温度差が小さく、
第１空隙部内の酸素濃度を高精度に制御できた。これに
よって所定の低酸素濃度になった状態の被測定ガス中の
可燃物質を、第１酸素ポンピングセルにより酸素を汲み
入れながら燃焼させ、その汲み入れられた酸素量に相当
する量の酸素が第２空隙部より第２酸素ポンピングセル
で汲み出されることとなり、可燃物質濃度を高精度に検
出することができた。また、加熱ヒータの面状の発熱部
が第１空隙部、第２空隙部及び酸素濃度測定セルと投影
図上で重なり合う位置にあるので、検出器のセンサー部
の加熱が容易であり、センサー部の温度を所定値に保持
するのに要する加熱ヒータの消費電力量を節減できるこ
とが分かった。Further, since the first gap is not elongated, the temperature difference in the first gap is small.
The oxygen concentration in the first gap could be controlled with high accuracy. As a result, the combustible substance in the gas to be measured in a state of a predetermined low oxygen concentration is burned while pumping oxygen by the first oxygen pumping cell, and the amount of oxygen corresponding to the pumped oxygen amount is reduced to the second level. It was pumped out from the second gap by the second oxygen pumping cell, and the concentration of combustible substances could be detected with high accuracy. Further, since the planar heating portion of the heater is located on the first gap portion, the second gap portion, and the oxygen concentration measurement cell on the projection view, the sensor portion of the detector is easily heated, and the sensor portion is easily heated. It has been found that the power consumption of the heater required to maintain the temperature of the heater at a predetermined value can be reduced.
【００５４】また、実施例２の図３に示したように、記
録計等を備えるマイクロコンピュータに検出器を接続
し、センサー部の酸素濃度や温度等の測定や制御を行な
うと同時に、出力された第１酸素ポンピングセルのポン
プ電流Ｉｐ1と第２酸素ポンピングセルのポンプ電流Ｉ
ｐ2の値から、あらかじめ標準ガスについて求めたデー
タに基き補正計算をマイクロコンピュータに実行させれ
ば、補正された精度の高い可燃物質濃度の検出値がオン
タイムで得られ、マイクロコンピュータを内燃機関の制
御計と接続すれば内燃機関の運転制御に即使用できるこ
とが分かった。Also, as shown in FIG. 3 of the second embodiment, a detector is connected to a microcomputer having a recorder and the like to measure and control the oxygen concentration and the temperature of the sensor portion, and at the same time, to output a signal. pump current I of the pump current Ip 1 of the first oxygen pumping cell the second oxygen pumping cell has
the value of p 2, advance or as it executes the standard gas correction calculation based on the data obtained for the microcomputer, the detection value of the high corrected accuracy combustible material concentration is obtained on time, the internal combustion engine the microcomputer It was found that if it was connected to the controller, it could be used immediately for operation control of the internal combustion engine.
【００５５】［実施例４］本発明の自動車排ガス触媒装
置のモニタリング方法について説明する。図１５は新し
い三元触媒の場合の、図１６はある期間使用して劣化し
た三元触媒の場合のモニタリングのメカニズムを示した
ものである。酸素センサの出力が大きい場合（すなわ
ち、リッチ域の場合）の可燃物質濃度検出器のポンプ電
流も大きくなり、排ガス中の可燃物質濃度に対応してい
る。触媒が劣化してくると、新品の場合に比べて可燃物
質濃度検出器の出力が大きくなり、触媒装置の劣化の度
合いに対応する。[Embodiment 4] A monitoring method of the automobile exhaust gas catalytic converter of the present invention will be described. FIG. 15 shows the monitoring mechanism in the case of a new three-way catalyst, and FIG. 16 shows the monitoring mechanism in the case of a three-way catalyst deteriorated after being used for a certain period. When the output of the oxygen sensor is large (that is, in the case of the rich region), the pump current of the combustible substance concentration detector also becomes large, and corresponds to the combustible substance concentration in the exhaust gas. When the catalyst deteriorates, the output of the combustible substance concentration detector increases as compared with the case of a new catalyst, which corresponds to the degree of deterioration of the catalyst device.
【００５６】一方、酸素センサの出力が小さい場合（す
なわち、リーン域の場合）の可燃物質濃度検出器のポン
プ電流は、触媒が新しい時はほとんどゼロである。しか
し、劣化してくると、酸素貯蔵能力の低下による酸素の
増加並びに増加した窒素酸化物（ＮＯ）が第１空隙部内
で分解されて生じる酸素の増加のために、第１空隙部内
の酸素濃度が高まる。そして、第１酸素ポンピングセル
がこの酸素を汲み出すために作動するのにともない、第
２拡散通路を介して通じている第２空隙部の第２酸素ポ
ンピングセルでは酸素を汲み入れる方向にポンプ電流が
流れる。すなわち、ポンプ電流Ｉｐ2はマイナス電流と
して出力される。従って、以上のように酸素センサの出
力と可燃物質濃度検出器の出力とを対応させることによ
り、触媒装置の劣化度合いをモニタリングすることがで
きる。On the other hand, when the output of the oxygen sensor is small (that is, in the lean region), the pump current of the combustible substance concentration detector is almost zero when the catalyst is new. However, when the oxygen concentration deteriorates, the oxygen concentration in the first void portion increases due to an increase in oxygen due to a decrease in oxygen storage capacity and an increase in oxygen generated by decomposition of the increased nitrogen oxide (NO) in the first void portion. Increase. Then, as the first oxygen pumping cell operates to pump out this oxygen, the second oxygen pumping cell in the second void portion communicating through the second diffusion passage has a pump current in the direction of pumping oxygen. Flows. That is, the pump current Ip 2 is output as a negative current. Therefore, by associating the output of the oxygen sensor with the output of the combustible substance concentration detector as described above, the degree of deterioration of the catalyst device can be monitored.
【００５７】[0057]
【発明の効果】本発明の可燃物質濃度検出器を使用すれ
ば、可燃物質を燃焼分解させる第１空隙部内の酸素濃度
を高精度に制御できるため、被測定ガス中の可燃物質の
濃度が低いときにも、可燃物質濃度を精度よく実用的レ
ベルにおいて安定して検出できる。特に、酸素濃度測定
セルと酸素ポンピングセルが異なる固体電解質層に設け
られている構造とした場合には、酸素濃度測定セルの電
極と酸素ポンピングセルの電極との間に流れるリーク電
流が僅か又は電極間が絶縁されていることによってリー
ク電流が全く流れないので酸素濃度の測定精度が高ま
り、第１空隙部中の酸素濃度を一層精度よく制御でき
る。これによって、被測定ガス中の可燃物質の濃度が低
い場合であっても、可燃物質濃度を精度よく実用的レベ
ルにおいて安定して検出できる。According to the combustible substance concentration detector of the present invention, the concentration of the combustible substance in the gas to be measured is low because the concentration of oxygen in the first gap for burning and decomposing the combustible substance can be controlled with high accuracy. At times, the concentration of combustible substances can be detected accurately and stably at a practical level. In particular, when the oxygen concentration measurement cell and the oxygen pumping cell are configured to be provided in different solid electrolyte layers, a small amount of leakage current flows between the electrode of the oxygen concentration measurement cell and the electrode of the oxygen pumping cell or the electrode. Since the space is insulated, no leak current flows, so that the measurement accuracy of the oxygen concentration is improved, and the oxygen concentration in the first void portion can be controlled more accurately. Thus, even if the concentration of the combustible substance in the gas to be measured is low, the concentration of the combustible substance can be detected accurately and stably at a practical level.
【００５８】特に、実施例２の可燃物質濃度検出器で
は、酸素濃度測定セルの電極と第２酸素ポンピングセル
の電極との間に電流リークがないので、第１空隙部内の
酸素濃度を精度よく制御でき、これによって第１空隙部
内の酸素濃度を狭い範囲の一定値に制御できる。第１空
隙部内の酸素濃度がばらつくと、ばらつきがそのまま可
燃物質濃度の検出値に影響し、第１空隙部内の酸素濃度
の変動量が即誤差となる。たとえば、第１空隙部内の酸
素濃度が１ｐｐｍ変動したとすると、数ｐｐｍ程度の可
燃物質濃度を検出するときの誤差としては影響が大き
い。実施例２の可燃物質濃度検出器では、第１空隙部内
の酸素濃度のばらつきを±０．０１ｐｐｍ程度以内に制
御できる。また、第２空隙部が多孔質材料で充填されて
いれば、第２空隙部の有効容積が小さく、第２酸素ポン
ピングセルのポンプ電流Ｉｐ2が短時間で平衡値に到達
する。したがって、可燃物質濃度を検出するときの応答
時間が短縮される。In particular, in the combustible substance concentration detector according to the second embodiment, since there is no current leak between the electrode of the oxygen concentration measuring cell and the electrode of the second oxygen pumping cell, the oxygen concentration in the first void portion can be accurately measured. The oxygen concentration in the first gap can be controlled to a constant value in a narrow range. When the oxygen concentration in the first gap varies, the variation directly affects the detected value of the combustible substance concentration, and the amount of change in the oxygen concentration in the first gap immediately becomes an error. For example, assuming that the oxygen concentration in the first void portion fluctuates by 1 ppm, an error when detecting a combustible substance concentration of about several ppm has a large effect. In the combustible substance concentration detector according to the second embodiment, the variation in the oxygen concentration in the first gap can be controlled within about ± 0.01 ppm. The second gap section if it is filled with a porous material, the effective volume of the second cavity portion is small, the pump current Ip 2 of the second oxygen pumping cell reaches an equilibrium value in a short time. Therefore, the response time when detecting the combustible substance concentration is reduced.
【００５９】また、本発明の可燃物質濃度の検出方法に
よれば、被測定ガス中に含まれる酸素濃度による可燃物
質濃度の検出値に対する影響を補正して除くことがで
き、さらに精度の高い検出値を安定して得ることができ
る。また、マイクロコンピュータを可燃物質濃度検出器
に付設しておくことによって、補正された可燃物質濃度
の検出値をオンタイムで得ることができ、内燃機関など
の燃焼機の制御系への接続が容易となる。また、本発明
の自動車排ガス触媒装置のモニタリング方法によれば、
従来の２本のＥＧＯセンサまたはＵＥＧＯセンサを使用
する方法に比べて精度の高いモニタリングが可能であ
る。Further, according to the method for detecting the concentration of combustible substances according to the present invention, the influence of the concentration of oxygen contained in the gas to be measured on the detected value of the concentration of combustible substances can be corrected and removed, and the detection with higher accuracy The value can be obtained stably. In addition, by providing a microcomputer to the combustible substance concentration detector, a corrected detected value of the combustible substance concentration can be obtained on-time, which facilitates connection to a control system of a combustion machine such as an internal combustion engine. Becomes Further, according to the monitoring method of the automobile exhaust gas catalyst device of the present invention,
Higher-precision monitoring is possible as compared with the conventional method using two EGO sensors or UEGO sensors.
【図１】 本発明の可燃物質濃度検出器の一例を示す先
端部の断面図。FIG. 1 is a sectional view of a tip portion showing an example of a combustible substance concentration detector of the present invention.
【図２】 本発明の可燃物質濃度検出器の他の一例を示
す平面図。FIG. 2 is a plan view showing another example of the combustible substance concentration detector of the present invention.
【図３】 図２のＢ−Ｂ’拡大縦断面図に制御系の系統
図を付記した図。FIG. 3 is a diagram in which a system diagram of a control system is added to the BB ′ enlarged longitudinal sectional view of FIG. 2;
【図４】 本発明の可燃物質濃度検出器を製造するとき
のレイアウトの斜視図。FIG. 4 is a perspective view of a layout when the combustible substance concentration detector of the present invention is manufactured.
【図５】 本発明の可燃物質濃度検出器に用いられる加
熱ヒータの平面図。FIG. 5 is a plan view of a heater used in the combustible substance concentration detector of the present invention.
【図６】 第２酸素ポンピングセルに流れるポンプ電流
Ｉｐ2と可燃物質濃度との関係を示すグラフ。FIG. 6 is a graph showing a relationship between a pump current Ip 2 flowing through a second oxygen pumping cell and a combustible substance concentration.
【図７】 比較例であるＵＥＧＯセンサのポンプ電流と
可燃物質濃度との関係を示すグラフ。FIG. 7 is a graph showing a relationship between a pump current and a combustible substance concentration of a UEGO sensor as a comparative example.
【図８】 第２酸素ポンピングセルのポンプ電流Ｉｐ2
に対する印加電圧の影響を示すグラフ。FIG. 8 shows the pump current Ip 2 of the second oxygen pumping cell.
5 is a graph showing the effect of applied voltage on the temperature.
【図９】 ポンプ電流Ｉｐ1とＩｐ2との相関関係を示す
グラフ。FIG. 9 is a graph showing a correlation between pump currents Ip 1 and Ip 2 .
【図１０】 酸素濃度とポンプ電流Ｉｐ2との関係を示
すグラフ。FIG. 10 is a graph showing a relationship between oxygen concentration and pump current Ip 2 .
【図１１】 実機での評価システムの構成を示す模式
図。FIG. 11 is a schematic diagram showing a configuration of an evaluation system in an actual machine.
【図１２】 ポンプ電流を電圧に変換して出力するため
の回路図。FIG. 12 is a circuit diagram for converting a pump current into a voltage and outputting the voltage.
【図１３】 実機評価における検出器の出力例を説明す
るための図。FIG. 13 is a view for explaining an output example of a detector in actual machine evaluation.
【図１４】 実機評価における検出器のポンプ電流と可
燃物質濃度との関係を示すグラフ。FIG. 14 is a graph showing a relationship between a pump current of a detector and a flammable substance concentration in actual machine evaluation.
【図１５】 新しい触媒をモニタリングする場合の検出
器の作動状態を説明するための図。FIG. 15 is a diagram for explaining an operation state of a detector when monitoring a new catalyst.
【図１６】 劣化した触媒をモニタリングする場合の検
出器の作動状態を説明するための図。FIG. 16 is a diagram for explaining an operation state of a detector when monitoring a deteriorated catalyst.
【図１７】 従来のＵＥＧＯセンサの先端部の断面図。FIG. 17 is a cross-sectional view of the tip of a conventional UEGO sensor.
１：第１拡散通路 ２：第１空隙部 ３：第２拡散通路 ４：第２空隙部 ５−１，５−２，‥‥，５−７：固体電解質層 ６：第１酸素ポンピングセル ７：酸素濃度測定セル ８：第２酸素ポンピングセル ９−ａ，９−ｂ：加熱ヒータ １１−１，１１−２，‥‥，１１−５：絶縁膜 １５：第１酸素ポンピングセルの電源部 １６：第１酸素ポンピングセルの電流計 １７：ポテンショメータ １８：第２酸素ポンピングセルの電流計 １９：第２酸素ポンピングセルの電源部 ２０：マイクロコンピュータ ２１：記録計 ２２：発熱部 ２３：白金のリード線 ２４：加熱ヒータ 1: first diffusion passage 2: first gap 3: second diffusion passage 4: second gap 5-1, 5-2, Δ, 5-7: solid electrolyte layer 6: first oxygen pumping cell 7 : Oxygen concentration measuring cell 8: Second oxygen pumping cell 9-a, 9-b: Heater 11-1, 11-2, ‥‥, 11-5: Insulating film 15: Power supply section of first oxygen pumping cell 16 : Ammeter of the first oxygen pumping cell 17: potentiometer 18: ammeter of the second oxygen pumping cell 19: power supply section of the second oxygen pumping cell 20: microcomputer 21: recorder 22: heating section 23: platinum lead wire 24: heater
───────────────────────────────────────────────────── フロントページの続き (72)発明者 黒木 由美 名古屋市瑞穂区高辻町14番18号 日本特殊 陶業株式会社内 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Yumi Kuroki 14-18 Takatsuji-cho, Mizuho-ku, Nagoya Japan Special Ceramics Co., Ltd.
Claims (19)
解質層を多孔質の電極で挟んでなる第１酸素ポンピング
セル及び酸素濃度測定セルを有する第１空隙部と、薄板
状の酸素イオン導電体よりなる固体電解質層を多孔質の
電極で挟んでなる第２酸素ポンピングセルを有する第２
空隙部と、第１空隙部を被測定ガス側に連通する第１拡
散通路と、第１空隙部を第２空隙部に連通する第２拡散
通路とを備えてなる可燃物質濃度検出器。1. A first void having a first oxygen pumping cell and an oxygen concentration measuring cell in which a solid electrolyte layer made of a thin plate oxygen ion conductor is sandwiched between porous electrodes, and a thin plate oxygen ion conductive material. A second oxygen pumping cell comprising a solid electrolyte layer made of a body sandwiched between porous electrodes.
A combustible substance concentration detector comprising: a cavity; a first diffusion passage communicating the first cavity with the gas to be measured; and a second diffusion passage communicating the first cavity with the second cavity.
解質層を多孔質の電極で挟んでなる第１酸素ポンピング
セル及び酸素濃度測定セルを有する第１空隙部と、薄板
状の酸素イオン導電体よりなる固体電解質層を多孔質の
電極で挟んでなる第２酸素ポンピングセルを有する第２
空隙部と、第１空隙部を被測定ガス側に連通する第１拡
散通路と、第１空隙部を第２空隙部に連通する第２拡散
通路とを備える固体電解質層が積層されてなる可燃物質
濃度検出器であって、第１酸素ポンピングセル、酸素濃
度測定セル及び第２酸素ポンピングセルがいずれも互い
に異なる固体電解質層に設けられていることを特徴とす
る可燃物質濃度検出器。2. A first void having a first oxygen pumping cell and an oxygen concentration measuring cell in which a solid electrolyte layer made of a thin plate oxygen ion conductor is sandwiched between porous electrodes; A second oxygen pumping cell comprising a solid electrolyte layer made of a body sandwiched between porous electrodes.
A flammable solid electrolyte layer including a gap, a first diffusion path connecting the first gap to the gas to be measured, and a second diffusion path connecting the first gap to the second gap. A substance concentration detector, wherein the first oxygen pumping cell, the oxygen concentration measurement cell, and the second oxygen pumping cell are all provided in different solid electrolyte layers.
ックスである請求項１または請求項２に記載の可燃物質
濃度検出器。3. The detector according to claim 1, wherein the oxygen ion conductor is zirconia ceramics.
絶縁層によって、酸素濃度測定セルの電極が第１酸素ポ
ンピングセル及び第２酸素ポンピングセルの電極と電気
的に絶縁されている請求項１〜３に記載の可燃物質濃度
検出器。4. An electrode of an oxygen concentration measuring cell is electrically insulated from an electrode of a first oxygen pumping cell and an electrode of a second oxygen pumping cell by an insulating film or an insulating layer provided between the solid electrolyte layers. Item 4. A combustible substance concentration detector according to any one of Items 1 to 3.
項４に記載の可燃物質濃度検出器。5. The detector according to claim 4, wherein the insulating film or the insulating layer is made of ceramic.
請求項４または請求項５に記載の可燃物質濃度検出器。6. The detector according to claim 4, wherein the insulating film or the insulating layer is made of high-purity alumina.
容積の５０％以下である請求項１〜６のいずれかに記載
の可燃物質濃度検出器。7. The combustible substance concentration detector according to claim 1, wherein the effective volume of the second void is 50% or less of the effective volume of the first void.
な方向に投影したとき、第１空隙部と第２空隙部とが互
いに概ね重なり合う位置にあり、第１空隙部と第２空隙
部の間の固体電解質層を貫通して固体電解質層に垂直な
方向に伸びる第２拡散通路によって第１空隙部と第２空
隙部とが連通されている請求項１〜７のいずれかに記載
の可燃物質濃度検出器。8. When the combustible substance concentration detector is projected in a direction perpendicular to the solid electrolyte layer, the first gap and the second gap are located at positions substantially overlapping each other, and the first gap and the second gap are provided. The first void portion and the second void portion are communicated with each other by a second diffusion passage extending through the solid electrolyte layer and extending in a direction perpendicular to the solid electrolyte layer. Combustible substance concentration detector.
請求項１〜８のいずれかに記載の可燃物質濃度検出器。9. The combustible substance concentration detector according to claim 1, wherein the second void portion is filled with a porous material.
ウム、イリジウム、レニウムから選ばれるいずれかの金
属又はその合金からなる請求項１〜９のいずれかに記載
の可燃物質濃度検出器。10. The combustible substance concentration detector according to claim 1, wherein the porous electrode is made of any metal selected from platinum, rhodium, palladium, iridium, and rhenium or an alloy thereof.
金、ロジウム、パラジウム、イリジウム、レニウムから
選ばれるいずれかの金属又はその合金と、Ａｇ，Ａｕ，
Ｎｉ，Ｃｏ，Ｃｒ，Ｆｅ，Ｍｎ，Ｃｕ，Ｔｉ，Ａｌ，Ｐ
ｂ，Ｚｎ，Ｓｎ，Ｉｎから選ばれる少なくとも１種とを
含有する請求項１〜１０のいずれかに記載の可燃物質濃
度検出器。11. A porous electrode provided in the first void portion is made of a metal selected from platinum, rhodium, palladium, iridium, rhenium or an alloy thereof, and Ag, Au,
Ni, Co, Cr, Fe, Mn, Cu, Ti, Al, P
The combustible substance concentration detector according to any one of claims 1 to 10, further comprising at least one selected from b, Zn, Sn, and In.
を有する加熱ヒータを設けた層が積層され、可燃物質濃
度検出器を固体電解質層に垂直な方向に投影したとき第
１空隙部、第２空隙部及び面状の発熱部が互いに概ね重
なり合う位置にある請求項８に記載の可燃物質濃度検出
器。12. A layer provided with a heater having a planar heating portion is laminated on the laminated solid electrolyte layer, and the first void portion is formed when the combustible substance concentration detector is projected in a direction perpendicular to the solid electrolyte layer. 9. The combustible substance concentration detector according to claim 8, wherein the second gap portion and the planar heating portion are located at positions substantially overlapping each other.
された固体電解質層を挟むように配設されている請求項
１２に記載の可燃物質濃度検出器。13. The combustible substance concentration detector according to claim 12, wherein a plurality of layers provided with heaters are provided, and are disposed so as to sandwich the stacked solid electrolyte layers.
電解質層との間に、第１酸素ポンピングセルの第１空隙
部に対向する側の面または第２酸素ポンピングセルの第
２空隙部に対向する側の面と外気とを連通するための外
気連絡通路が設けられている請求項１２に記載の可燃物
質濃度検出器。14. A surface of the first oxygen pumping cell facing the first void or a second void of the second oxygen pumping cell, between the layer provided with the heater and the stacked solid electrolyte layer. 13. The combustible substance concentration detector according to claim 12, further comprising an outside air communication passage for communicating the outside air with a surface on the side opposite to the outside air passage.
金又は白金合金の複合材料からなり、加熱ヒータのリー
ド部が白金又は白金合金からなり、加熱ヒータのリード
部の常温抵抗値が加熱ヒータ全体の常温抵抗値の３０％
以下である請求項１２〜１４のいずれかに記載の可燃物
質濃度検出器。15. A heating part of the heater is made of a composite material of ceramics and platinum or a platinum alloy, a lead part of the heater is made of platinum or a platinum alloy, and a normal temperature resistance value of the lead part of the heater is equal to that of the whole heater. 30% of normal temperature resistance
The combustible substance concentration detector according to any one of claims 12 to 14, wherein:
電解質層が多孔質の電極で挟まれた第１酸素ポンピング
セル及び酸素濃度測定セルを有する第１空隙部と、薄板
状の酸素イオン導電体からなる固体電解質層が多孔質の
電極で挟まれた第２酸素ポンピングセルを有する第２空
隙部と、第１空隙部を被測定ガス側と連通する第１拡散
通路と、第１空隙部を第２空隙部に連通する第２拡散通
路とを備えてなる可燃物質濃度検出器を用い、第１拡散
通路を通して第１空隙部に導入した被測定ガス中の可燃
物質を前記多孔質の電極上で燃焼させ、酸素濃度測定セ
ルで酸素濃度を監視しつつ第１酸素ポンピングセルによ
り酸素を導入して第１空隙部の酸素濃度を制御し、所定
の酸素濃度とした被測定ガスを第２拡散通路を通して第
２空隙部に導入し、第２酸素ポンピングセルに一定電圧
を印加して第２空隙部内の酸素を抜き取り、このとき第
１酸素ポンピングセルに流れるポンプ電流Ｉｐ1または
第２酸素ポンピングセルに流れるポンプ電流Ｉｐ2に基
いて被測定ガス中の可燃物質濃度を検出することを特徴
とする可燃物質濃度の検出方法。16. A first void having a first oxygen pumping cell and an oxygen concentration measuring cell in which a solid electrolyte layer made of a thin plate oxygen ion conductor is sandwiched between porous electrodes, and a thin plate oxygen ion conductive material. A second gap having a second oxygen pumping cell in which a solid electrolyte layer composed of a body is sandwiched between porous electrodes, a first diffusion passage communicating the first gap with the gas to be measured, and a first gap Using a combustible substance concentration detector having a second diffusion passage communicating with the second gap, and using the porous electrode to convert the combustible substance in the gas to be measured introduced into the first gap through the first diffusion passage. The above-mentioned combustion is performed, and while monitoring the oxygen concentration in the oxygen concentration measurement cell, oxygen is introduced by the first oxygen pumping cell to control the oxygen concentration in the first gap, and the measured gas having the predetermined oxygen concentration is converted into the second gas. Introduced into the second gap through the diffusion passage Extracting oxygen in the second gap portion by applying a constant voltage to the second oxygen pumping cell, the this time based on the pump current Ip 2 flowing through the pump current Ip 1 or the second oxygen pumping cell flowing in the first oxygen pumping cell A method for detecting a combustible substance concentration, comprising detecting a combustible substance concentration in a measurement gas.
の検出値に及ぼす影響を、あらかじめ酸素の濃度と可燃
物質の濃度が異なり、かつ既知である標準ガスを用いて
測定したデータに基いて補正する請求項１６に記載の可
燃物質濃度の検出方法。17. The effect of the oxygen concentration in the gas to be measured on the detected value of the flammable substance concentration is determined based on data previously measured using a standard gas in which the concentration of the flammable substance differs from the concentration of the flammable substance. 17. The method for detecting a combustible substance concentration according to claim 16, wherein the correction is performed by correcting the temperature.
可燃物質濃度とポンプ電流Ｉｐ1またはＩｐ2との間に所
定の函数関係があると仮定し、あらかじめマイクロコン
ピュータのメモリーに蓄積したデータに基きマイクロコ
ンピュータで演算して補正した可燃物質濃度を求める請
求項１７に記載の可燃物質濃度の検出方法。18. Even if the oxygen concentration in the gas to be measured changes,
Assuming a predetermined function relationship between the combustible substance concentration and the pump current Ip 1 or Ip 2, finding a combustible material concentration corrected by calculating a microcomputer based on the data stored in advance in the microcomputer memory according Item 18. The method for detecting a combustible substance concentration according to Item 17.
請求項１〜１５のいずれかに記載の可燃物質濃度検出器
と、前記触媒装置の上流側に取り付けた酸素濃度検出器
とを備え、前記可燃物質濃度検出器により検出される可
燃物質濃度と前記酸素濃度検出器により検出される酸素
濃度とから前記触媒装置の酸素貯蔵能力をモニタリング
することを特徴とする自動車排ガス触媒装置のモニタリ
ング方法。19. A flammable substance concentration detector according to any one of claims 1 to 15 attached downstream of a catalyst device, and an oxygen concentration detector attached upstream of the catalyst device. A method for monitoring an automobile exhaust gas catalytic device, comprising: monitoring an oxygen storage capacity of the catalytic device from a combustible substance concentration detected by the combustible substance concentration detector and an oxygen concentration detected by the oxygen concentration detector.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP8188571A JPH1019843A (en) | 1996-06-28 | 1996-06-28 | Apparatus and method for detecting concentration of combustible material |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP8188571A JPH1019843A (en) | 1996-06-28 | 1996-06-28 | Apparatus and method for detecting concentration of combustible material |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH1019843A true JPH1019843A (en) | 1998-01-23 |
Family
ID=16226024
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP8188571A Pending JPH1019843A (en) | 1996-06-28 | 1996-06-28 | Apparatus and method for detecting concentration of combustible material |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH1019843A (en) |
Cited By (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH11148918A (en) * | 1997-09-09 | 1999-06-02 | Ngk Spark Plug Co Ltd | Gas sensor, gas sensor system using the same and production of gas sensor |
| JP2000162175A (en) * | 1998-11-25 | 2000-06-16 | Ngk Spark Plug Co Ltd | Gas sensor, its production, and gas sensor system |
| JP2000171434A (en) * | 1998-12-04 | 2000-06-23 | Ngk Spark Plug Co Ltd | Gas sensor and combustible gas component concentration measuring apparatus using the same |
| KR200456796Y1 (en) | 2009-02-20 | 2011-11-21 | 한국산업안전보건공단 | Organic solvent fume diffusion chamber and concentration measuring device having the same |
| JP2013088119A (en) * | 2011-10-13 | 2013-05-13 | Nippon Soken Inc | Gas sensor element and gas sensor for internal combustion engine |
| CN103511045A (en) * | 2012-06-29 | 2014-01-15 | 现代自动车株式会社 | System for sensing SOF of diesel engine |
| DE112017004028T5 (en) | 2016-08-09 | 2019-05-02 | Ngk Insulators, Ltd. | gas sensor |
| CN113447555A (en) * | 2020-03-25 | 2021-09-28 | 日本碍子株式会社 | Gas sensor and method for controlling operation of gas sensor |
-
1996
- 1996-06-28 JP JP8188571A patent/JPH1019843A/en active Pending
Cited By (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH11148918A (en) * | 1997-09-09 | 1999-06-02 | Ngk Spark Plug Co Ltd | Gas sensor, gas sensor system using the same and production of gas sensor |
| JP2000162175A (en) * | 1998-11-25 | 2000-06-16 | Ngk Spark Plug Co Ltd | Gas sensor, its production, and gas sensor system |
| JP2000171434A (en) * | 1998-12-04 | 2000-06-23 | Ngk Spark Plug Co Ltd | Gas sensor and combustible gas component concentration measuring apparatus using the same |
| KR200456796Y1 (en) | 2009-02-20 | 2011-11-21 | 한국산업안전보건공단 | Organic solvent fume diffusion chamber and concentration measuring device having the same |
| JP2013088119A (en) * | 2011-10-13 | 2013-05-13 | Nippon Soken Inc | Gas sensor element and gas sensor for internal combustion engine |
| CN103511045A (en) * | 2012-06-29 | 2014-01-15 | 现代自动车株式会社 | System for sensing SOF of diesel engine |
| DE112017004028T5 (en) | 2016-08-09 | 2019-05-02 | Ngk Insulators, Ltd. | gas sensor |
| US10845327B2 (en) | 2016-08-09 | 2020-11-24 | Ngk Insulators, Ltd. | Gas sensor |
| CN113447555A (en) * | 2020-03-25 | 2021-09-28 | 日本碍子株式会社 | Gas sensor and method for controlling operation of gas sensor |
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