JP3314439B2 - Air-fuel ratio detection device - Google Patents
Air-fuel ratio detection deviceInfo
- Publication number
- JP3314439B2 JP3314439B2 JP03617093A JP3617093A JP3314439B2 JP 3314439 B2 JP3314439 B2 JP 3314439B2 JP 03617093 A JP03617093 A JP 03617093A JP 3617093 A JP3617093 A JP 3617093A JP 3314439 B2 JP3314439 B2 JP 3314439B2
- Authority
- JP
- Japan
- Prior art keywords
- air
- electric heater
- fuel ratio
- atmosphere
- side electrode
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
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- Measuring Oxygen Concentration In Cells (AREA)
Description
【０００１】[0001]
【産業上の利用分野】本発明は，車両用内燃機関の空燃
比検知装置に関するもので，特に熱効率と応答性とに優
れた電熱ヒータの構造に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an air-fuel ratio detecting device for an internal combustion engine of a vehicle, and more particularly to a structure of an electric heater excellent in thermal efficiency and responsiveness.
【０００２】[0002]
【従来技術】車両用の内燃機関の空燃比が適切でないと
煤の発生による排気汚染，失火による未燃燃料の排出，
出力の低下等の不具合を生ずる。そのため，内燃機関に
おける空燃比の調節は極めて重要であり，そのため，空
燃比の検知が行われる。2. Description of the Related Art If the air-fuel ratio of an internal combustion engine for a vehicle is not appropriate, exhaust pollution due to soot generation, emission of unburned fuel due to misfire,
Problems such as a decrease in output may occur. Therefore, the adjustment of the air-fuel ratio in the internal combustion engine is extremely important, and therefore, the detection of the air-fuel ratio is performed.
【０００３】上記空燃比の検知装置には，酸素イオン伝
導体である固体電解質の両面に電極を設けて電気化学的
セルを構成したものが多く用いられている。そして，電
極の一方に排気ガスを他方に大気を導入して，両者の酸
素濃度差によって生ずる電極間の電位差から内燃機関の
空燃比を検知する。また，広域の空燃比検知する場合に
は，電極間に一定電圧を印加して固体電解質に酸素イオ
ン電流を流し，拡散抵抗層によりその電流を制御して限
界電流を測定する方法が用いられる。As the above-mentioned air-fuel ratio detecting device, a device in which electrodes are provided on both surfaces of a solid electrolyte which is an oxygen ion conductor to constitute an electrochemical cell is often used. Then, exhaust gas is introduced into one of the electrodes and air is introduced into the other, and the air-fuel ratio of the internal combustion engine is detected from the potential difference between the electrodes caused by the difference in oxygen concentration between the two. When detecting a wide range of air-fuel ratio, a method is used in which a constant voltage is applied between the electrodes to flow an oxygen ion current through the solid electrolyte, and the current is controlled by a diffusion resistance layer to measure a limiting current.
【０００４】なお，上記固定電解質において酸素イオン
伝導を発生させるためには高温度（約６５０℃以上）が
必要であり，そのため，電熱ヒータを用いてセルを熱し
ている。例えば，図１０，図１１に示すように，空燃比
検知装置の検出部（セル部）９０は，固体電解質１１の
上下両面１１１，１１２に電極９１，９２を設け，上面
１１１に排気を導入し，下面１１２にはダクト９３を介
して大気５１を導入する。In order to generate oxygen ion conduction in the above fixed electrolyte, a high temperature (about 650 ° C. or higher) is required. Therefore, the cell is heated using an electric heater. For example, as shown in FIGS. 10 and 11, the detection unit (cell unit) 90 of the air-fuel ratio detection device is provided with electrodes 91 and 92 on the upper and lower surfaces 111 and 112 of the solid electrolyte 11, and exhaust gas is introduced into the upper surface 111. The air 51 is introduced into the lower surface 112 through a duct 93.
【０００５】そして，図１０に示すように，ダクト９３
の下面に絶縁部材９４に埋設した電熱ヒータ９５１を配
設する（タイプＡ）。または，図１１に示すように，固
体電解質１１とダクト９３の中間かつ電極９２の側方に
電熱ヒータ９５２を配設する（タイプＢ）。該電熱ヒー
タ９５２も絶縁部材９４に埋設されている。[0005] Then, as shown in FIG.
The electric heater 951 embedded in the insulating member 94 is disposed on the lower surface of the substrate (type A). Alternatively, as shown in FIG. 11, an electric heater 952 is provided between the solid electrolyte 11 and the duct 93 and beside the electrode 92 (type B). The electric heater 952 is also embedded in the insulating member 94.
【０００６】そして，上記図１０，図１１に示す空燃比
検知装置の検出部（セル部）９０は，ステンレス等のカ
バーに収容され（図３参照）エンジンの排気通路に装着
される。なお，車両用の空燃比検知装置においては，エ
ンジンの始動直後からできるだけ早急に空燃比検知装置
を作動させるという必要性があるから，電熱ヒータ９５
１，９５２は上記検出部９０を短時間のうちに加熱する
必要がある。The detecting portion (cell portion) 90 of the air-fuel ratio detecting device shown in FIGS. 10 and 11 is housed in a cover made of stainless steel or the like (see FIG. 3) and mounted on the exhaust passage of the engine. In the air-fuel ratio detecting device for a vehicle, it is necessary to operate the air-fuel ratio detecting device as soon as possible immediately after the start of the engine.
1, 952 needs to heat the detection unit 90 in a short time.
【０００７】[0007]
【解決しようとする課題】しかしながら，上記従来の空
燃比検知装置には次のような問題がある。即ち，従来の
空燃比検知装置においては，電熱ヒータ９５１はダクト
９３を介設して反応部（電極部）を加熱したり（図１０
タイプＡ），電熱ヒータ９５２は反応部（電極部）の側
方から反応部を加熱する（図１１タイプＢ）。However, the above-mentioned conventional air-fuel ratio detecting device has the following problems. That is, in the conventional air-fuel ratio detecting device, the electric heater 951 heats the reaction section (electrode section) through the duct 93 (see FIG. 10).
Type A), the electric heater 952 heats the reaction part from the side of the reaction part (electrode part) (FIG. 11 type B).
【０００８】そのため，熱損失が多くなり，加熱効率が
悪く，消費電力が多いという問題がある。また，消費電
力に比べて相対的に昇温の応答特性が悪く，電源投入後
の空燃比検知装置の立ち上がりが遅くなる。本発明は，
かかる従来の問題点に鑑みて，電熱ヒータの加熱効率が
良好で，電源投入後の立ち上がり時間の短い，内燃機関
の空燃比検知装置を提供しようとするものである。Therefore, there is a problem that heat loss is increased, heating efficiency is poor, and power consumption is large. In addition, the response characteristic of the temperature rise is relatively poor compared to the power consumption, and the rise of the air-fuel ratio detection device after the power is turned on is delayed. The present invention
In view of such a conventional problem, an object of the present invention is to provide an air-fuel ratio detection device for an internal combustion engine, which has a good heating efficiency of an electric heater and a short rise time after power-on.
【０００９】[0009]
【課題の解決手段】本発明は，酸素イオン伝導体である
固体電解質の一面に排気側電極を，それと対向する他の
面に大気側電極を設けて電気化学的セルを形成した内燃
機関の空燃比検知装置であって，大気側電極に対向する
位置には，大気ダクトと連通した大気室を配設し，該大
気室と上記大気側電極との間には，絶縁シートを介して
大気側電極と接する電熱ヒータを配設し，該電熱ヒータ
の大気室側には，さらに別の絶縁シートが設けられてお
り，上記双方の絶縁シートは上記電熱ヒータを回避して
穿設した通気穴を有することを特徴とする内燃機関の空
燃比検知装置にある。According to the present invention, there is provided an internal combustion engine having an electrochemical cell formed by providing an exhaust-side electrode on one surface of a solid electrolyte which is an oxygen ion conductor and an atmospheric-side electrode on another surface facing the solid electrolyte. An air chamber communicating with an air duct is disposed at a position facing the air electrode on the fuel side, and an air chamber is provided between the air chamber and the air electrode via an insulating sheet. It disposed the electric heater in contact with the electrode, electric heater
Another insulating sheet is provided on the atmosphere chamber side of
In addition, in the air-fuel ratio detecting device for an internal combustion engine, both of the insulating sheets have ventilation holes formed to avoid the electric heater.
【００１０】本発明において最も注目すべきことは，大
気側電極には絶縁シートを介して電熱ヒータを配設して
あり，該電熱ヒータの大気室側には，さらに別の絶縁シ
ートが設けられており，上記双方の絶縁シートは上記電
熱ヒータを回避して穿設した通気穴を有するよう構成し
たことである。そして，上記大気側電極に対向する位置
には，大気ダクトと連通した大気室を配設し，上記電熱
ヒータは大気側電極と大気室との間に配設してある。[0010] Most notably in the present invention, the atmosphere-side electrode is Yes and disposed electric heater via an insulating sheet, on the air chamber side of the electric heater, a further insulating sheet
A heat sink is provided, and both of the insulating sheets are configured to have ventilation holes formed so as to avoid the electric heater. An air chamber communicating with the air duct is provided at a position facing the air electrode, and the electric heater is provided between the air electrode and the air chamber.
【００１１】[0011]
【作用及び効果】本発明の空燃比検知装置においては，
電熱ヒータは絶縁シートを介して大気側電極と接してお
り，反応部である大気側電極を間近から加熱する。従っ
て，電熱ヒータは従来装置のように大気側電極の側方
（図１１）やダクト（図１０，符号９３）など余分なも
のを殆ど加熱することなく，大気側電極を直接的に加熱
する。そのため，加熱効率が高い。[Operation and Effect] In the air-fuel ratio detecting device of the present invention,
The electric heater is in contact with the atmosphere-side electrode via an insulating sheet, and heats the atmosphere-side electrode, which is a reaction section, from close up. Therefore, the electric heater directly heats the atmosphere-side electrode without substantially heating extra parts such as the side of the atmosphere-side electrode (FIG. 11) and the duct (FIG. 10, reference numeral 93) unlike the conventional apparatus. Therefore, the heating efficiency is high.
【００１２】また，電熱ヒータと大気側電極との間には
絶縁シートを介設させてあるから両者の間の電気的な絶
縁も確保される。そして，両者間の絶縁の確保のために
は，ごく薄い絶縁シートで充分であるから，大気側電極
はすぐに熱せられる。従って，ごく短時間のうちにセル
を機能させ空燃比検知装置を作動させることができる。
即ち，熱効率と始動応答性の良い空燃比検知装置を得る
ことができる。Further, since an insulating sheet is interposed between the electric heater and the atmosphere-side electrode, electrical insulation between the two is also ensured. Then, since an extremely thin insulating sheet is sufficient to ensure insulation between the two, the atmosphere-side electrode is immediately heated. Therefore, the cell can be operated and the air-fuel ratio detecting device can be operated in a very short time.
That is, it is possible to obtain an air-fuel ratio detection device having good thermal efficiency and start-up response.
【００１３】なお，上記絶縁シートには通気穴を穿設し
てあるから，大気は該通気穴を通して大気側電極に導入
することができる。上記のように，本発明によれば，電
熱ヒータの加熱効率が良好で，電源投入後の立ち上がり
時間の短い内燃機関の空燃比検知装置を提供することが
できる。Since the insulating sheet is provided with a ventilation hole, the atmosphere can be introduced into the atmosphere-side electrode through the ventilation hole. As described above, according to the present invention, it is possible to provide an air-fuel ratio detecting device for an internal combustion engine having a good heating efficiency of an electric heater and a short rise time after power-on.
【００１４】[0014]
実施例１ 本発明の実施例に係る空燃比検知装置につき，図１〜図
９を用いて説明する。本例は，図１に示すように，酸素
イオン伝導体である固体電解質１１の一面である上面１
１１に排気側電極１３を，それと対向する他の面である
下面１１２に大気側電極１２を設けて電気化学的セルで
ある検出部１０を形成した車両用内燃機関の空燃比検知
装置１（図３）である。Embodiment 1 An air-fuel ratio detecting device according to an embodiment of the present invention will be described with reference to FIGS. In this example, as shown in FIG. 1, an upper surface 1 which is one surface of a solid electrolyte 11 which is an oxygen ion conductor is used.
An air-fuel ratio detecting device 1 for an internal combustion engine for a vehicle, in which an exhaust-side electrode 13 is provided on a lower surface 11 and an atmosphere-side electrode 12 is provided on a lower surface 112 opposite to the exhaust-side electrode 13 to form a detector 10 as an electrochemical cell (FIG. 3).
【００１５】そして，上記検出部１０の大気側電極１２
に対向する位置には，大気ダクト３８と連通した大気室
３２を配設し，該大気室３２と上記大気側電極１２との
間には，電気的な絶縁シート３０を介して大気側電極１
２と接する電熱ヒータ２０を配設し，該電熱ヒータの大
気室側には，さらに別の絶縁シートが設けられており，
上記双方の絶縁シートは電熱ヒータ２０を回避して穿設
した通気穴３１を有している。上記双方の絶縁シートの
一方は図１にかかる絶縁シート３０，もう一方は絶縁板
３５である。 The atmosphere-side electrode 12 of the detection unit 10
An atmosphere chamber 32 communicating with an atmosphere duct 38 is provided at a position facing the atmosphere side electrode 12, and between the atmosphere chamber 32 and the atmosphere side electrode 12 via an electric insulating sheet 30.
The electric heater 20 in contact with 2 disposed, large the electric heater
Another insulating sheet is provided on the air chamber side.
Both of the insulating sheets have ventilation holes 31 formed to avoid the electric heater 20. Both of the above insulation sheets
One is the insulating sheet 30 according to FIG. 1 and the other is the insulating plate
35.
【００１６】以下それぞれについて詳説する。本例は，
図３に示すように，ハウジング４０の内部に検出部１０
を収容し，該検出部１０と接続したリード線４１を有す
る空燃比検知装置１である。ハウジング４０は略中央部
にフランジ４３を設けた胴部４２を有し，該胴部４２の
下方には排気通路に挿入される排気カバー４４を有し，
胴部４２の上方には大気と接する大気カバー４５を有し
ている。Hereinafter, each of them will be described in detail. In this example,
As shown in FIG.
Is an air-fuel ratio detection device 1 having a lead wire 41 connected to the detection unit 10. The housing 40 has a body 42 provided with a flange 43 at a substantially central portion, and an exhaust cover 44 inserted into an exhaust passage below the body 42.
Above the body 42, there is an air cover 45 in contact with the air.
【００１７】排気カバー４４は，図３に示すように，ス
テンレス製の内部カバー４４１と外部カバー４４２とを
有し，両カバー４４１，４４２には排気口４４３，４４
４を設けてある。一方，大気カバー４５は，胴部４２に
取り付けられたメインカバー４５１と，該メインカバー
４５１の後端部を被うサブカバー４５２とを有してお
り，それぞれのカバー４５１，４５２には大気口４５
３，４５４が設けてある。As shown in FIG. 3, the exhaust cover 44 has an inner cover 441 and an outer cover 442 made of stainless steel, and the two covers 441 and 442 have exhaust ports 443 and 44, respectively.
4 are provided. On the other hand, the air cover 45 has a main cover 451 attached to the body 42 and a sub-cover 452 covering the rear end of the main cover 451. Each of the covers 451 and 452 has an air port. 45
3,454 are provided.
【００１８】上記大気口４５３，４５４は後述する検出
部１０の大気ダクト３８と連通している。そして両大気
口４５３，４５４の間には，防水用の撥水フィルタ４６
が挿入されている。そして，検出部１０は，絶縁部材４
２１に挟持されて上記胴部４２に収容されている。ま
た，検出部１０に接続されたリード線４１はセル起電力
を取り出す一対の信号線と電熱ヒータに電力を供給する
一対のヒータ線とからなる。The atmosphere ports 453 and 454 communicate with an atmosphere duct 38 of the detection unit 10 described later. A water-repellent filter 46 for waterproofing is provided between the air ports 453 and 454.
Is inserted. Then, the detecting unit 10 includes the insulating member 4
21 and housed in the body 42. The lead wire 41 connected to the detection unit 10 includes a pair of signal lines for extracting cell electromotive force and a pair of heater lines for supplying electric power to the electric heater.
【００１９】本例の空燃比検知装置１の検出部１０は，
図１に示すように，固体電解質１１であるジルコニアシ
ートの上面１１１に白金の排気側電極１３を，下面１１
２に白金の大気側電極１２を設けてある。そして，固体
電解質１１の下部には，熱伝導率の低いジルコニアもし
くはムライトからなる大気ダクト３８が配設されてお
り，大気室３２が形成されている。また，固体電解質１
１の下面１１２には絶縁シート３０とさらに別の絶縁シ
ートである絶縁板３５とに挟持された電熱ヒータ２０が
取り付けられている。The detection unit 10 of the air-fuel ratio detection device 1 of the present embodiment
As shown in FIG. 1, a platinum exhaust side electrode 13 is provided on an upper surface 111 of a zirconia sheet which is a solid electrolyte 11, and a lower surface 11 is provided.
2, an atmosphere-side electrode 12 made of platinum is provided. An air duct 38 made of zirconia or mullite having a low thermal conductivity is provided below the solid electrolyte 11, and an air chamber 32 is formed. In addition, solid electrolyte 1
The lower surface 112 of the first insulating sheet 30 and another insulating sheet
An electric heater 20 sandwiched between an insulating plate 35 serving as a heat exchanger is attached.
【００２０】絶縁板３５は，図２に示すように２０μｍ
以上の厚さを有するアルミナ等のセラミックシートであ
り，その上面に白金属金属ペーストを印刷した電熱ヒー
タ２０が形成されている。そして，電熱ヒータ２０の上
面には，厚さ２０μｍ以上のアルミナ等のセラミックの
絶縁シート３０を貼着してある。The insulating plate 35 has a thickness of 20 μm as shown in FIG.
It is a ceramic sheet made of alumina or the like having the above thickness, and an electric heater 20 having a white metal paste printed thereon is formed on the upper surface thereof. A ceramic insulating sheet 30 such as alumina having a thickness of 20 μm or more is adhered to the upper surface of the electric heater 20.
【００２１】そして，電熱ヒータ２０を避けながら上記
絶縁板３５と絶縁シート３０とを貫通する通気穴３１が
多数穿設されている。上記通気穴３１は検知ガスが分子
拡散律速となるよう１００μｍ以上の外径を有する円柱
状の通気穴であり，大気室３２の大気５１（図１）を大
気側電極１２に接触させている。A large number of ventilation holes 31 penetrating the insulating plate 35 and the insulating sheet 30 while avoiding the electric heater 20 are formed. The vent hole 31 is a cylindrical vent hole having an outer diameter of 100 μm or more so that the detection gas is controlled by molecular diffusion. The vent 51 of the atmosphere chamber 32 (FIG. 1) is brought into contact with the atmosphere electrode 12.
【００２２】大気側電極１２と排気側電極１３とは，図
２に示すように，幅広の反応部１２１，１３１と前記リ
ード線４１の信号線と接続される細長い線状部１２２，
１３２とを有している。また，電熱ヒータ２０は，前記
リード線４１のヒータ線と接続される幅広のリード部２
０１と細線状の発熱部２０２とを有している。As shown in FIG. 2, the atmosphere-side electrode 12 and the exhaust-side electrode 13 have wide reaction portions 121 and 131 and elongated linear portions 122 connected to the signal lines of the lead wires 41.
132. The electric heater 20 has a wide lead 2 connected to the heater wire of the lead wire 41.
01 and a thin linear heating section 202.
【００２３】なお，上記大気側電極１２の反応部１２１
の面積Ｓ1 と電熱ヒータ２０の発熱部２０２の面積Ｓ2
との間には０．１Ｓ1 ≦Ｓ2 ≦０．５Ｓ1 なる関係があ
る。即ち発熱部２０２の面積Ｓ2 は大気側電極１２１の
反応部１２１面積Ｓ1 の１０％から５０％の間にある。The reaction section 121 of the atmosphere side electrode 12
Area S 1 and the area of the heat generating portion 202 of the electric heater 20 S 2
Has a relationship of 0.1 S 1 ≦ S 2 ≦ 0.5S 1 . That is, the area S 2 of the heat generating section 202 is between 10% and 50% of the area S 1 of the reaction section 121 of the atmosphere-side electrode 121.
【００２４】その理由は通気穴３１を穿設し，必要な電
気抵抗を得るためには上記発熱部２０２の面積Ｓ2 は反
応部１２１の面積Ｓ1 の５０％以下にしないと絶縁板３
５上に発熱部２０２を形成することが困難となるからで
ある。The reason is that in order to obtain the required electric resistance, the area S 2 of the heating section 202 must be 50% or less of the area S 1 of the reaction section 121 in order to obtain the required electric resistance.
This is because it becomes difficult to form the heat-generating portion 202 on the surface 5.
【００２５】一方，上記発熱部２０２の面積Ｓ2 が小さ
くなりすぎると，温度分布が不均一となると共に，絶縁
部材である絶縁シート３０と絶縁板３５で失われる熱が
大きくなり，電熱ヒータ２０の大気側電極１２の加熱効
率が低下する。それ故，上記面積Ｓ2 は大気側電極１２
の反応部１２１の面積Ｓ1 の１０％以上は必要である。On the other hand, if the area S 2 of the heat generating portion 202 is too small, the temperature distribution becomes non-uniform, and the heat lost by the insulating sheet 30 and the insulating plate 35 as insulating members increases, and the electric heater 20 , The heating efficiency of the atmosphere-side electrode 12 decreases. Therefore, the area S 2 is equal to the atmospheric electrode 12.
More than 10% of the area S 1 of the reaction unit 121 is required.
【００２６】また，発熱部２０２の固体電解質１１への
投影図の幅は，上記反応部１２１の幅よりも小さくして
ある。これによって，反応部１２１以外の部分を加熱す
ることによる加熱ロスを少なくすることができるからで
ある。The width of the projected view of the heating section 202 onto the solid electrolyte 11 is smaller than the width of the reaction section 121. Thereby, a heating loss due to heating of a portion other than the reaction section 121 can be reduced.
【００２７】また，通気穴３１の大気側電極１２との接
触面積の総和Ｓ3 は，上記大気側電極１２の反応部１２
１の面積Ｓ1 に対して２０％以上で５０％以下であるこ
とが好ましい（０．２Ｓ1 ≦Ｓ3 ≦０．５Ｓ1 ）。その
理由は次の通りである。まず，電熱ヒータ２０の発熱部
２０２の面積Ｓ2 と上記通気穴３１の面積Ｓ3の和（Ｓ
2 ＋Ｓ3 ）は，これらが大気側電極１２の反応部と重な
っていないと無駄であるから，反応部面積Ｓ1 以下であ
る（Ｓ2 ＋Ｓ3 ≦Ｓ1 ）。一方，前記のように発熱部面
積Ｓ2 は，最大で反応部面積Ｓ1 の５０％であるから，
このときを基準にすれば通気穴面積Ｓ3 は反応部面積Ｓ
1 の５０％以下である（Ｓ3 ≦１／２Ｓ1 ）。The sum S 3 of the contact area of the ventilation hole 31 with the atmosphere-side electrode 12 is determined by the reaction area 12 of the atmosphere-side electrode 12.
It is preferred for one of the area S 1 is 50% or less at 20% or more (0.2S 1 ≦ S 3 ≦ 0.5S 1). The reason is as follows. First, the sum of the area S 2 of the heating portion 202 of the electric heater 20 and the area S 3 of the ventilation hole 31 (S
2 + S 3 ) is useless unless they overlap with the reaction part of the atmosphere-side electrode 12, and is therefore not more than the reaction part area S 1 (S 2 + S 3 ≦ S 1 ). On the other hand, as described above, the heat generating area S 2 is 50% of the reaction area S 1 at the maximum.
Based on this time, the vent hole area S 3 is the reaction area S
1 % or less (S 3 ≦ 1 / 2S 1 ).
【００２８】また，通気穴３１の面積Ｓ3 が小さくなり
すぎると，大気が接する面積すなわちセルの反応面積が
小さくなり，セルの電流容量が低下しセルから検出信号
を取り出したときの検出エラーが大きくなる。それ故，
通気穴面積Ｓ3 は反応部面積Ｓ1 の２０％以上は必要で
ある（Ｓ3 ≧１／５Ｓ1 ）。On the other hand, if the area S 3 of the ventilation hole 31 is too small, the area in contact with the atmosphere, that is, the reaction area of the cell is reduced, and the current capacity of the cell is reduced. growing. Therefore,
The area S 3 of the vent hole needs to be at least 20% of the area S 1 of the reaction part (S 3 ≧ 1 / 5S 1 ).
【００２９】なお，電熱ヒータ２０の発熱部２０２及び
通気穴３１の形状には，各種の形状が考えられる。例え
ば，図４に示すように，発熱部２０２を前後方向につづ
ら折りに形成し，通気穴３１を均一な円形断面形状とす
る。また，図５に示すように，通気穴３１の断面形状を
長円形としてもよい。Various shapes are conceivable for the shape of the heat generating portion 202 and the ventilation hole 31 of the electric heater 20. For example, as shown in FIG. 4, the heat generating portion 202 is formed in a zigzag manner in the front-rear direction, and the vent hole 31 has a uniform circular cross-sectional shape. Further, as shown in FIG. 5, the cross-sectional shape of the ventilation hole 31 may be an oval.
【００３０】また，図６に示すように，発熱部２０２を
右左方向に蛇行するように形成し，通気穴３１の断面形
状を大小の異なった大きさの円形形状としてもよい。ま
た，図７に示すように，通気穴３１の断面形状を方形と
することもできる。また，通気穴３１の断面形状は三角
形や五角以上の多角形でもよい。As shown in FIG. 6, the heat generating portion 202 may be formed so as to meander right and left, and the cross-sectional shape of the ventilation hole 31 may be a circular shape having different sizes. In addition, as shown in FIG. 7, the cross-sectional shape of the ventilation hole 31 can be square. Further, the cross-sectional shape of the ventilation hole 31 may be a triangle or a polygon having five or more angles.
【００３１】次に本例の検出部１０の製法について述べ
る。まず，アルミナグリーンシートからなる絶縁板３５
上にスクリーン印刷等の方法により白金を主成分とする
ペーストを塗布し，乾燥して電熱ヒータ２０を形成す
る。Next, a method of manufacturing the detection unit 10 of this embodiment will be described. First, an insulating plate 35 made of alumina green sheet is used.
A paste containing platinum as a main component is applied thereon by screen printing or the like, and dried to form the electric heater 20.
【００３２】次に，アルミナグリーンシートからなる絶
縁シート３０を絶縁板３５の電熱ヒータ２０形成面上に
貼り合わせて一体化する。続いて一体化した絶縁シート
３０と絶縁板３５とを貫通する通気穴３１をパンチング
マシーンを用いて穿設し，ヒータユニットとして完成す
る。Next, an insulating sheet 30 made of an alumina green sheet is bonded on the surface of the insulating plate 35 on which the electric heater 20 is formed to be integrated. Subsequently, a ventilation hole 31 penetrating the integrated insulating sheet 30 and insulating plate 35 is formed by using a punching machine to complete a heater unit.
【００３３】一方，大気ダクト３８はジルコニアもしく
はムライトを主成分として，射出成形又はプレス成形等
によって形成する。また，ジルコニア系固体電解質１１
のグリーンシートの両面には白金を主成分とするペース
トをスクリーン印刷等の方法により塗布し乾燥させて大
気側電極１２と排気側電極１３とを形成しセルユニット
を完成する。On the other hand, the air duct 38 is made of zirconia or mullite as a main component by injection molding or press molding. The zirconia-based solid electrolyte 11
A paste containing platinum as a main component is applied to both surfaces of the green sheet by a method such as screen printing and dried to form an atmosphere-side electrode 12 and an exhaust-side electrode 13, thereby completing a cell unit.
【００３４】次に，上記大気ダクト３８の上端部に，上
記ヒータユニットをバインダを用いて貼り合わせる。さ
らにその上に上記セルユニットをバインダを介して積層
させて，全体を同時焼成する。Next, the heater unit is bonded to the upper end of the air duct 38 using a binder. Further, the cell units are stacked thereon via a binder, and the whole is simultaneously fired.
【００３５】そして，白金線を埋め込んで，前記大気側
電極１２及び排気側電極１３の線状部１２２，１３２及
び電熱ヒータ２０のリード部２０１と接続し，リード線
４１との接続部を形成する。または，上記線状部１２
２，１３２及びリード部２０１を延長させてリード線４
１との接続部を形成する方法もある。Then, a platinum wire is embedded and connected to the linear portions 122 and 132 of the atmosphere-side electrode 12 and the exhaust-side electrode 13 and the lead portion 201 of the electric heater 20 to form a connection portion with the lead wire 41. . Alternatively, the linear portion 12
2, 132 and the lead portion 201 to extend the lead wire 4
There is also a method of forming a connection portion with the first.
【００３６】次に，本例の空燃比検知装置１の作用効果
について述べる。本例の空燃比検知装置１においては，
検出部１０における電熱ヒータ２０は絶縁シート３０を
介して大気側電極１２と接している。そして，絶縁シー
ト３０は極めて薄く，電熱ヒータ２０が大気側電極１２
を間近から加熱するから余分なものに熱を奪われること
が少なく加熱効率が良好である。Next, the operation and effect of the air-fuel ratio detecting device 1 of this embodiment will be described. In the air-fuel ratio detection device 1 of this example,
The electric heater 20 in the detection unit 10 is in contact with the atmosphere-side electrode 12 via the insulating sheet 30. The insulating sheet 30 is extremely thin, and the electric heater 20 is connected to the atmosphere side electrode 12.
Is heated from a short distance, so that heat is not deprived by extra materials and the heating efficiency is good.
【００３７】また，薄い絶縁シート３０を介して大気側
電極１２を直接熱するから極めて短時間のうちちに大気
側電極１２部の温度を上昇させることができる。図８は
本例を従来装置のタイプＡ（図１０）とタイプＢ（図１
１）と比較して電熱ヒータの加熱効率を図示したもので
ある。図８から知られるように，本例の加熱効率は従来
装置より２〜３倍に上昇した。Further, since the atmosphere-side electrode 12 is directly heated via the thin insulating sheet 30, the temperature of the atmosphere-side electrode 12 can be increased in a very short time. FIG. 8 shows this example of a conventional device of type A (FIG. 10) and type B (FIG. 1).
2 illustrates the heating efficiency of the electric heater in comparison with 1). As can be seen from FIG. 8, the heating efficiency of the present example was increased two to three times as compared with the conventional apparatus.
【００３８】また，本例の空燃比検知装置の昇温特性
は，図９に示すように，従来装置のタイプＡ（図１０）
及びタイプＢ（図１１）に比べて昇温時間が１／３〜１
／５に短縮された。上記のように，本例によれば，電熱
ヒータの加熱効率が良好で，電源投入後の立ち上がり時
間の短い内燃機関の空燃比検知装置を提供することがで
きる。Further, as shown in FIG. 9, the temperature rise characteristics of the air-fuel ratio detecting device of this embodiment are of the type A (FIG. 10) of the conventional device.
And the heating time is 1/3 to 1 as compared with the type B (FIG. 11).
/ 5. As described above, according to the present embodiment, it is possible to provide an air-fuel ratio detection device for an internal combustion engine having a good heating efficiency of the electric heater and a short rise time after the power is turned on.
【図１】実施例の空燃比検知装置の検出部の断面図。FIG. 1 is a sectional view of a detection unit of an air-fuel ratio detection device according to an embodiment.
【図２】図１に示す検出部の分解斜視図。FIG. 2 is an exploded perspective view of the detection unit shown in FIG.
【図３】実施例の空燃比検知装置の断面図。FIG. 3 is a cross-sectional view of the air-fuel ratio detection device according to the embodiment.
【図４】実施例にかかる電熱ヒータ及び通気穴の形状と
配置例を示す説明図。FIG. 4 is an explanatory diagram showing examples of shapes and arrangements of an electric heater and a ventilation hole according to the embodiment.
【図５】実施例にかかる電熱ヒータ及び通気穴の形状と
配置例を示す他の説明図。FIG. 5 is another explanatory diagram showing examples of shapes and arrangements of the electric heater and the ventilation hole according to the embodiment.
【図６】実施例にかかる電熱ヒータ及び通気穴の形状と
配置例を示す他の説明図。FIG. 6 is another explanatory diagram showing examples of shapes and arrangements of the electric heater and the vent hole according to the embodiment.
【図７】実施例にかかる電熱ヒータ及び通気穴の形状と
配置例を示す他の説明図。FIG. 7 is another explanatory diagram showing examples of shapes and arrangements of the electric heater and the ventilation hole according to the embodiment.
【図８】実施例及び従来例の空燃比検知装置の電熱ヒー
タの熱効率比較図。FIG. 8 is a graph showing a comparison between the thermal efficiency of the electric heater of the air-fuel ratio detecting apparatus of the embodiment and the conventional example.
【図９】実施例及び従来例の空燃比検知装置の昇温特性
比較図。FIG. 9 is a graph showing a comparison between the temperature rise characteristics of the air-fuel ratio detecting device of the embodiment and the conventional example.
【図１０】従来例の空燃比検知装置（タイプＡ）の検出
部断面図。FIG. 10 is a sectional view of a detection section of a conventional air-fuel ratio detection device (type A).
【図１１】他の従来例の空燃比検知装置（タイプＢ）の
検出部断面図。FIG. 11 is a cross-sectional view of a detection section of another conventional air-fuel ratio detection device (type B).
１．．．空燃比検知装置， １０．．．検出部， １１．．．固体電解質， １２．．．大気側電極， １３．．．排気側電極， ２０．．．電熱ヒータ， ３０．．．絶縁シート， ３１．．．通気穴， ３２．．．大気室， ３８．．．大気ダクト， ４１．．．リード線， 1. . . 9. Air-fuel ratio detector, . . Detection unit, 11. . . Solid electrolyte, 12. . . 12. atmosphere side electrode, . . Exhaust-side electrode, 20. . . Electric heater, 30. . . Insulating sheet, 31. . . Vent holes, 32. . . Atmosphere chamber, 38. . . Atmospheric duct, 41. . . Lead,
───────────────────────────────────────────────────── フロントページの続き (72)発明者 鈴木 雅寿 愛知県刈谷市昭和町１丁目１番地 日本 電装株式会社内 (56)参考文献 特開 昭55−125448（ＪＰ，Ａ) (58)調査した分野(Int.Cl.7，ＤＢ名) G01N 27/409 ────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Masahisa Suzuki 1-1-1 Showa-cho, Kariya-shi, Aichi Japan Inside Denso Co., Ltd. (56) References JP-A-55-125448 (JP, A) (58) Survey Field (Int.Cl. 7 , DB name) G01N 27/409
Claims (1)
面に排気側電極を，それと対向する他の面に大気側電極
を設けて電気化学的セルを形成した内燃機関の空燃比検
知装置であって， 大気側電極に対向する位置には，大気ダクトと連通した
大気室を配設し，該大気室と上記大気側電極との間に
は，絶縁シートを介して大気側電極と接する電熱ヒータ
を配設し，該電熱ヒータの大気室側には，さらに別の絶
縁シートが設けられており， 上記双方の絶縁シートは上記 電熱ヒータを回避して穿設
した通気穴を有することを特徴とする内燃機関の空燃比
検知装置。1. An air-fuel ratio detecting device for an internal combustion engine, comprising: an exhaust-side electrode provided on one surface of a solid electrolyte which is an oxygen ion conductor; and an atmosphere-side electrode provided on another surface facing the exhaust electrode. An air chamber communicating with the air duct is provided at a position facing the air electrode, and an electric heater in contact with the air electrode via an insulating sheet is provided between the air chamber and the air electrode. A further insulation is provided on the atmosphere side of the electric heater.
An air-fuel ratio detecting device for an internal combustion engine, wherein an edge sheet is provided, and both of the insulating sheets have ventilation holes formed to avoid the electric heater.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP03617093A JP3314439B2 (en) | 1993-02-01 | 1993-02-01 | Air-fuel ratio detection device |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP03617093A JP3314439B2 (en) | 1993-02-01 | 1993-02-01 | Air-fuel ratio detection device |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH06229976A JPH06229976A (en) | 1994-08-19 |
| JP3314439B2 true JP3314439B2 (en) | 2002-08-12 |
Family
ID=12462282
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP03617093A Expired - Lifetime JP3314439B2 (en) | 1993-02-01 | 1993-02-01 | Air-fuel ratio detection device |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP3314439B2 (en) |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5874664A (en) * | 1996-01-30 | 1999-02-23 | Denso Corporation | Air fuel ratio sensor and method for assembling the same |
| DE19950999B4 (en) * | 1999-10-22 | 2013-07-25 | Robert Bosch Gmbh | Planar sensor element |
| DE102006014248A1 (en) * | 2006-03-28 | 2007-10-04 | Robert Bosch Gmbh | Sensor unit e.g. wideband oxygen sensor, for determining oxygen content in exhaust gas of internal combustion engine, has heater with insulation that surrounds heating unit, where heating unit exhibits meandering profile |
-
1993
- 1993-02-01 JP JP03617093A patent/JP3314439B2/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| JPH06229976A (en) | 1994-08-19 |
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