JPH0248055B2 - - Google Patents
Info
- Publication number
- JPH0248055B2 JPH0248055B2 JP58109770A JP10977083A JPH0248055B2 JP H0248055 B2 JPH0248055 B2 JP H0248055B2 JP 58109770 A JP58109770 A JP 58109770A JP 10977083 A JP10977083 A JP 10977083A JP H0248055 B2 JPH0248055 B2 JP H0248055B2
- Authority
- JP
- Japan
- Prior art keywords
- detection
- substrate
- electrodes
- smoke
- temperature compensation
- 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
Links
- 238000001514 detection method Methods 0.000 claims description 53
- 239000000779 smoke Substances 0.000 claims description 44
- 239000000758 substrate Substances 0.000 claims description 36
- 238000010438 heat treatment Methods 0.000 claims description 20
- 239000011247 coating layer Substances 0.000 claims description 6
- 239000011810 insulating material Substances 0.000 claims description 2
- BASFCYQUMIYNBI-UHFFFAOYSA-N platinum Substances [Pt] BASFCYQUMIYNBI-UHFFFAOYSA-N 0.000 description 7
- 239000000843 powder Substances 0.000 description 6
- 238000010586 diagram Methods 0.000 description 4
- 239000000463 material Substances 0.000 description 4
- 238000000034 method Methods 0.000 description 4
- 229910052697 platinum Inorganic materials 0.000 description 4
- 229910052799 carbon Inorganic materials 0.000 description 3
- 238000000465 moulding Methods 0.000 description 3
- LTPBRCUWZOMYOC-UHFFFAOYSA-N Beryllium oxide Chemical compound O=[Be] LTPBRCUWZOMYOC-UHFFFAOYSA-N 0.000 description 2
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 2
- CPLXHLVBOLITMK-UHFFFAOYSA-N Magnesium oxide Chemical compound [Mg]=O CPLXHLVBOLITMK-UHFFFAOYSA-N 0.000 description 2
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 2
- MCMNRKCIXSYSNV-UHFFFAOYSA-N Zirconium dioxide Chemical compound O=[Zr]=O MCMNRKCIXSYSNV-UHFFFAOYSA-N 0.000 description 2
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 description 2
- 238000002485 combustion reaction Methods 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 238000010304 firing Methods 0.000 description 2
- 238000004519 manufacturing process Methods 0.000 description 2
- 229910052581 Si3N4 Inorganic materials 0.000 description 1
- -1 acrylic ester Chemical class 0.000 description 1
- 230000007423 decrease Effects 0.000 description 1
- 230000003247 decreasing effect Effects 0.000 description 1
- 230000006866 deterioration Effects 0.000 description 1
- 239000002270 dispersing agent Substances 0.000 description 1
- 238000007606 doctor blade method Methods 0.000 description 1
- 238000010292 electrical insulation Methods 0.000 description 1
- 239000012777 electrically insulating material Substances 0.000 description 1
- 238000003912 environmental pollution Methods 0.000 description 1
- 238000002474 experimental method Methods 0.000 description 1
- 229910052737 gold Inorganic materials 0.000 description 1
- 239000003779 heat-resistant material Substances 0.000 description 1
- 238000009413 insulation Methods 0.000 description 1
- 239000010410 layer Substances 0.000 description 1
- 239000000395 magnesium oxide Substances 0.000 description 1
- 229910052751 metal Inorganic materials 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 238000002156 mixing Methods 0.000 description 1
- 229910052750 molybdenum Inorganic materials 0.000 description 1
- 229910000510 noble metal Inorganic materials 0.000 description 1
- 229910052763 palladium Inorganic materials 0.000 description 1
- 239000002245 particle Substances 0.000 description 1
- 239000004014 plasticizer Substances 0.000 description 1
- 238000000746 purification Methods 0.000 description 1
- 239000011347 resin Substances 0.000 description 1
- 229920005989 resin Polymers 0.000 description 1
- 229910052703 rhodium Inorganic materials 0.000 description 1
- 238000004904 shortening Methods 0.000 description 1
- 239000000377 silicon dioxide Substances 0.000 description 1
- HQVNEWCFYHHQES-UHFFFAOYSA-N silicon nitride Chemical compound N12[Si]34N5[Si]62N3[Si]51N64 HQVNEWCFYHHQES-UHFFFAOYSA-N 0.000 description 1
- 229910052709 silver Inorganic materials 0.000 description 1
- 239000002002 slurry Substances 0.000 description 1
- 239000002904 solvent Substances 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- 229910052715 tantalum Inorganic materials 0.000 description 1
- 229910052721 tungsten Inorganic materials 0.000 description 1
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N27/00—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means
- G01N27/02—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating impedance
- G01N27/04—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating impedance by investigating resistance
- G01N27/06—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating impedance by investigating resistance of a liquid
- G01N27/07—Construction of measuring vessels; Electrodes therefor
Landscapes
- Chemical & Material Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Electrochemistry (AREA)
- Physics & Mathematics (AREA)
- Health & Medical Sciences (AREA)
- Life Sciences & Earth Sciences (AREA)
- Analytical Chemistry (AREA)
- Biochemistry (AREA)
- General Health & Medical Sciences (AREA)
- General Physics & Mathematics (AREA)
- Immunology (AREA)
- Pathology (AREA)
- Investigating Or Analyzing Materials By The Use Of Electric Means (AREA)
- Exhaust Silencers (AREA)
Description
本発明はデイーゼル機関などの内燃機関の排気
中に残在する微粒炭素（以下「スモーク」とい
う）を検出するスモークセンサに関するものであ
る。
不完全燃焼時のデイーゼル機関の排気中には、
一般にスモークと呼ばれる微粒炭素が存在し、こ
れが環境汚染の原因となつていることは知られて
いる。この様な有害物質を除去するために各種排
気浄化装置及びこれらと連動するガスセンサやス
モークセンサが提案されている。本発明者等も、
先に出願した特願昭58−73586号（特開昭59−
197847号公報参照）発明「スモークセンサ」の明
細書において、基板表面及び裏面にそれぞれ電極
及び発熱体を形成し、電極間にスモークが堆積す
ることによつて生じる抵抗値の変化を検出する一
方、堆積スモークを発熱体への通電によつて除去
し得るスモークセンサを提案した。しかしなが
ら、上記スモークセンサの場合、基板の抵抗温度
依存性により、検出部となつている電極間の抵抗
がスモークの堆積量のみならず排気温度の変化や
発熱体への通電量にも依存するため、基板温度が
高く且つスモーク濃度の低い条件での使用は不向
きであつた。
本発明は、検出用電極の近傍に温度補償用電極
を形成することによつて上記の難点を克服するこ
とのできたもので、その要旨とするところは、耐
熱性及び電気絶縁性を有する基板又は二以上の基
板からなる多層基板において、基板の表面に電極
間を検出部とする一対の検出用電極が形成され、
前記表面の前記電極と異なる部分、前記基板の裏
面又は前記基板と異なる他の基板の表面に電極間
を温度補償部とする一対の温度補償用電極が形成
され、前記検出部及び前記温度補償部の近傍に発
熱体を形成し、該発熱体により前記検出部を400
℃以上で且つ600℃以下に加熱し、前記検出部を
含む面及び温度補償部を含め、少なくとも検出部
を除く全面に気密な絶縁物質からなる被覆層を設
けることによつて検出部を露出させていることを
特徴とするスモーク濃度センサに存する。
以下図に示す実施例とともに説明する。
第１図は本発明スモークセンサの一実施例を示
す正面図、第２図は第１図Ａ−Ａ線断面図であ
る。４枚の基板からなる多層基板において、上か
ら二段目の平板状基板１の表面の一端に櫛歯状の
検出用電極２ａ，２ｂを形成し、電極間を検出部
３とし、他端に設けた検出用端子４ａ，４ｂと接
続する。第１図では示さないが、基板１の裏面に
は検出用電極２ａ，２ｂと同一形状で電極間を温
度補償部とする温度補償用電極５が形成され、他
端に設けた温度補償用端子６と接続する。本発明
スモーク濃度センサは検出部３にスモークが堆積
することによつて生じる電極間抵抗の変化を検出
するものであるが、スモークが検出部３以外の部
分に付着し、その部分の短縮による検出精度の劣
化を防止するため、基板１の検出部３、検出用電
極２ａ，２ｂ及び検出用端子４ａ，４ｂを除く表
面に被覆層７が積層されている。
第２図の最下段の基板８の表面には発熱体９が
蛇行型に形成され、上下貫通孔１０を経由して基
板８の裏面に設けた発熱体用端子１１と接続して
いる。温度補償用電極５と発熱体９の間を絶縁す
るために基板１と基板８の間に基板１２が挟まれ
るいる。
基板材料及び被覆層は、基板１、基板８、基板
１２及び被覆層７のすべてが同材質である場合が
工程上最も簡単であるが、電気絶縁性耐熱材料で
ある限り必ずしも同材質に限定されることはな
く、アルミナ、窒化珪素、ジルコニア、ベリリア
等の材料から選択し得る。基板の成形には加圧成
形法及びシート成形法のどちらも適用可能である
が、センサの小型化軽量化が要求される場合には
シート成形法が望ましい。
電極及び発熱体は、Pt、Rh、Au、Ag及びPd
などの貴金属粉又はＷ、Ta及びMoなどの耐熱金
属粉を含むペーストを生シート又は焼成基板上に
厚膜印刷したものが好適である。電極形状は、検
出部３にスモークが堆積した際に生じる電気抵抗
の変化を通常の電子回路により容易に検出できる
程度となるように使用態様に応じて線間隔及び線
長を考慮しなければならないが、線間隔が0.05mm
に満たないと電極間の絶縁抵抗が小さいため上記
抵抗変化を検出するのが困難となり、他方線間隔
が３mmを超えると一旦付着したスモークを除くの
が困難となるので線間隔は0.05mm〜３mmが望まし
い。
発熱体は検出部３に堆積したスモークを焼き切
ることを目的として設けられるものであるので、
検出部３が400〜600℃となるように膜厚及び線密
度を選定するのが望ましい。検出部の温度が400
℃に満たないとスモークを焼き切ることが困難に
なり、600℃を超えると電極間の抵抗変化が小さ
くなり、これを検出するのが困難になるからであ
る。
第３図は第１図及び第２図に示したスモークセ
ンサの製作工程の一例を示す斜視図である。
平均粒径1μｍのアルミナ粉末90重量％、シリ
カ５重量％、マグネシア５重量％、全無機粉末に
対し10重量部のアクリル酸エステル樹脂、同８重
量部の可塑剤及び同少量の分散剤を有機溶剤中で
混合し泥漿とし、ドクターブレード法によつて成
形することによつて生シートS1、同S8、同S7及び
同S12を製作した。生シートS1の表面に白金ペー
ストを用いて、焼成収縮後の線巾及び線間隔が共
に1.0mmとなるよう櫛歯状パターンP1、P2と端子
用パターンT1、T2とを印刷し、次いで上記表面
と全く同様に図示しない裏面にも印刷を施す。他
方生シートS8の表面には上記白金ペーストを用い
て発熱体９とする蛇行状パターンＨを印刷し、同
時に白金ペーストを貫通孔Q1，Q2に流れ込ませ
て、図示しない裏面に印刷した発熱体用端子１１
とする端子用パターンと連通させ、焼成後に発熱
体９と発熱体用端子１１とが導通するようにして
おく。次に生シートS1、S8、S7及びS12を熱圧着
し、大気中温度1600℃、保持時間１時間の条件で
焼成することによつてスモークセンサを製作し
た。このようにして得られたスモークセンサの電
気回路図を第４図に示す。Ｈは発熱体９の抵抗、
R1及びR2はそれぞれ検出用電極２ａ，２ｂ及び
温度補償用電極５の電極間抵抗、VHは発熱体用
入力電圧、VOはセンサ入力電圧、Ｖはセンサ出
力電圧である。これらにはＶ／VO＝R2／（R1＋
R2）という関係があるが、本実施例では検出用
電極と温度補償用電極とを同一基板の表裏面に同
一形状に形成したので、センサが清浄大気に晒さ
れている限りR1＝R2なる関係は温度に依存する
ことなく保持され、Ｖ／VO値が一定となる。と
ころがセンサがスモークを含む排気に晒される
と、検出部３にはスモークが堆積するが裏面の温
度補償部には堆積しないので、温度一定の条件下
ではその堆積量に応じてR1の値のみが減少し、
Ｖ／VO値が増加する。例えば検出部３の温度が
600℃になるように発熱体９に通電するとセンサ
が大気中に晒されている間はR1＝R2＝3000（ｋ
Ω）であつたが、センサをスモーク量５％の排気
に晒すとR1＝1000（ｋΩ）に低下した。従つて、
温度補償部を付設していないスモークセンサを用
いて未知のスモーク濃度を検出するためには、こ
のようなR1の抵抗変化を測定しなければならな
かつたので、十分な検出精度が得られなかつた
が、本発明によれば入力電圧VOをD.C.14（Ｖ）と
すると大気中ではR1＝R2＝3000（ｋΩ）より出力
電圧Ｖは７（Ｖ）となり、スモーク含有排気中で
はR1＝1000（ｋΩ）、R2＝3000（ｋΩ）より出力電
圧Ｖは10.5（Ｖ）となるので、このような出力電
圧Ｖの変化を測定することによつてスモーク濃度
を正確に検出することができるのである。
次に、更に、表１に示すスモーク濃度及び検出
部温度に於ける、このセンサの検出性能を確認す
る実験を行つた。その結果は表１に示す様に、検
出部の温度が400℃ないし550℃において、スモー
ク濃度を０％ないし60％の排気ガスに晒してセン
サの出力電圧を測定した処、スモーク濃度の変化
による検出用電極間の抵抗変化よりも、検出部温
度の変化による検出用電極間の抵抗変化が大きい
にもかかわらず、センサの出力電圧は、スモーク
濃度に対応した出力電圧が得られた。
The present invention relates to a smoke sensor that detects particulate carbon (hereinafter referred to as "smoke") remaining in the exhaust gas of an internal combustion engine such as a diesel engine. In the exhaust of a diesel engine during incomplete combustion,
It is known that particulate carbon, commonly called smoke, exists and is a cause of environmental pollution. In order to remove such harmful substances, various exhaust purification devices and gas sensors and smoke sensors that work with these devices have been proposed. The inventors also
Patent Application No. 73586 (1982) filed earlier
(Refer to Publication No. 197847) In the specification of the invention "smoke sensor", electrodes and heating elements are formed on the front and back surfaces of the substrate, respectively, and changes in resistance value caused by smoke deposited between the electrodes are detected. We have proposed a smoke sensor that can remove accumulated smoke by energizing a heating element. However, in the case of the above-mentioned smoke sensor, due to the temperature dependence of the resistance of the substrate, the resistance between the electrodes serving as the detection part depends not only on the amount of smoke accumulated, but also on changes in the exhaust temperature and the amount of current applied to the heating element. However, it was not suitable for use under conditions where the substrate temperature was high and the smoke concentration was low. The present invention has been able to overcome the above-mentioned difficulties by forming a temperature compensation electrode near the detection electrode. In a multilayer substrate consisting of two or more substrates, a pair of detection electrodes is formed on the surface of the substrate, with a detection portion between the electrodes,
A pair of temperature compensation electrodes is formed on a portion of the front surface different from the electrode, on the back surface of the substrate, or on a surface of another substrate different from the substrate, and a pair of temperature compensation electrodes is formed between the electrodes as a temperature compensation section, and the detection section and the temperature compensation section are formed. A heating element is formed near the detector, and the heating element causes the detection unit to
℃ or above and below 600℃, and expose the detection section by providing a coating layer made of an airtight insulating material on the entire surface including the detection section and the temperature compensation section, but excluding at least the detection section. The invention resides in a smoke density sensor characterized by: This will be explained below along with the embodiments shown in the figures. FIG. 1 is a front view showing an embodiment of the smoke sensor of the present invention, and FIG. 2 is a sectional view taken along the line A--A in FIG. In a multilayer substrate consisting of four substrates, comb-shaped detection electrodes 2a and 2b are formed at one end of the surface of the flat plate-like substrate 1 in the second stage from the top, a detection section 3 is formed between the electrodes, and a detection section 3 is formed at the other end. Connect to the provided detection terminals 4a and 4b. Although not shown in FIG. 1, a temperature compensation electrode 5 having the same shape as the detection electrodes 2a and 2b and having a temperature compensation portion between the electrodes is formed on the back surface of the substrate 1, and a temperature compensation terminal provided at the other end. Connect with 6. The smoke density sensor of the present invention detects a change in interelectrode resistance caused by smoke accumulating on the detection part 3, but smoke adheres to a part other than the detection part 3 and detection is caused by shortening of that part. In order to prevent deterioration of accuracy, a coating layer 7 is laminated on the surface of the substrate 1 except for the detection portion 3, the detection electrodes 2a, 2b, and the detection terminals 4a, 4b. A heating element 9 is formed in a meandering shape on the surface of the substrate 8 at the bottom of FIG. A substrate 12 is sandwiched between the substrate 1 and the substrate 8 to insulate the temperature compensation electrode 5 and the heating element 9. Regarding the substrate material and the coating layer, the process is easiest if the substrate 1, substrate 8, substrate 12, and coating layer 7 are all made of the same material, but they are not necessarily limited to the same material as long as they are electrically insulating and heat-resistant materials. It can be selected from materials such as alumina, silicon nitride, zirconia, beryllia, etc. Both a pressure molding method and a sheet molding method can be applied to mold the substrate, but the sheet molding method is preferable when the sensor is required to be smaller and lighter. Electrodes and heating elements are Pt, Rh, Au, Ag and Pd
It is preferable to print a thick film of a paste containing noble metal powder such as or heat-resistant metal powder such as W, Ta, and Mo on a raw sheet or fired substrate. Regarding the electrode shape, the line spacing and line length must be considered according to the mode of use so that the change in electrical resistance that occurs when smoke accumulates on the detection part 3 can be easily detected by a normal electronic circuit. However, the line spacing is 0.05mm
If the wire spacing is less than 3 mm, it will be difficult to detect the above resistance change due to the small insulation resistance between the electrodes, and on the other hand, if the wire spacing exceeds 3 mm, it will be difficult to remove smoke once it has adhered, so the wire spacing should be 0.05 mm to 3 mm. is desirable. Since the heating element is provided for the purpose of burning off the smoke accumulated on the detection part 3,
It is desirable to select the film thickness and linear density so that the temperature of the detection part 3 is 400 to 600°C. The temperature of the detection part is 400
This is because if the temperature is less than 600°C, it will be difficult to burn off the smoke, and if it exceeds 600°C, the resistance change between the electrodes will become small, making it difficult to detect. FIG. 3 is a perspective view showing an example of the manufacturing process of the smoke sensor shown in FIGS. 1 and 2. FIG. 90% by weight of alumina powder with an average particle size of 1 μm, 5% by weight of silica, 5% by weight of magnesia, 10 parts by weight of acrylic ester resin, 8 parts by weight of plasticizer, and the same amount of dispersant based on the total inorganic powder. Green sheets S 1 , S 8 , S 7 and S 12 were produced by mixing in a solvent to form a slurry and forming it by a doctor blade method. Using platinum paste on the surface of the raw sheet S 1 , comb-shaped patterns P 1 and P 2 and terminal patterns T 1 and T 2 are printed so that the line width and line spacing after shrinkage after firing are both 1.0 mm. Then, the back side (not shown) is also printed in the same manner as the front side. On the other hand, a serpentine pattern H serving as a heating element 9 was printed on the surface of the green sheet S 8 using the platinum paste, and at the same time, the platinum paste was flowed into the through holes Q 1 and Q 2 to print on the back surface (not shown). Heating element terminal 11
The heating element 9 and the heating element terminal 11 are made to communicate with each other after firing. Next, the raw sheets S 1 , S 8 , S 7 and S 12 were thermocompressed and fired in the atmosphere at a temperature of 1600° C. for a holding time of 1 hour to produce a smoke sensor. FIG. 4 shows an electrical circuit diagram of the smoke sensor thus obtained. H is the resistance of the heating element 9,
R 1 and R 2 are the interelectrode resistances of the detection electrodes 2a, 2b and the temperature compensation electrode 5, respectively, VH is the input voltage for the heating element, V O is the sensor input voltage, and V is the sensor output voltage. These include V/V O = R 2 / (R 1 +
In this example, the detection electrode and the temperature compensation electrode are formed in the same shape on the front and back surfaces of the same substrate, so as long as the sensor is exposed to clean air, R 1 = R. The relationship 2 is maintained regardless of temperature, and the V/V O value remains constant. However, when the sensor is exposed to exhaust gas containing smoke, smoke accumulates on the detection part 3 but does not accumulate on the temperature compensation part on the back side. Therefore, under conditions of constant temperature, the value of R 1 only changes depending on the amount of smoke accumulated. decreases,
V/V O value increases. For example, if the temperature of the detection part 3 is
When the heating element 9 is energized so that the temperature reaches 600℃, R 1 = R 2 = 3000 (k) while the sensor is exposed to the atmosphere.
Ω), but when the sensor was exposed to exhaust gas with a smoke amount of 5%, R 1 decreased to 1000 (kΩ). Therefore,
In order to detect an unknown smoke concentration using a smoke sensor that is not equipped with a temperature compensation section, it is necessary to measure the resistance change of R 1 , so it is difficult to obtain sufficient detection accuracy. However, according to the present invention, when the input voltage V O is DC14 (V), the output voltage V is 7 (V) in the atmosphere because R 1 = R 2 = 3000 (kΩ), and in the exhaust gas containing smoke, R 1 = 1000 (kΩ) and R 2 = 3000 (kΩ), the output voltage V is 10.5 (V), so by measuring the change in the output voltage V, it is possible to accurately detect the smoke density. It can be done. Next, an experiment was conducted to confirm the detection performance of this sensor at the smoke concentration and detection part temperature shown in Table 1. The results are shown in Table 1. When the temperature of the detection part was 400°C to 550°C, the output voltage of the sensor was measured by exposing it to exhaust gas with a smoke concentration of 0% to 60%. Even though the resistance change between the detection electrodes due to a change in the detection part temperature was larger than the resistance change between the detection electrodes, an output voltage corresponding to the smoke concentration was obtained as the output voltage of the sensor.
【表】
上記実施例では、温度補償用電極を表面に検出
用電極が形成されている基板の裏面に形成した
が、温度補償用電極の位置はこれに限定されるも
のではなく、第４図に示した電気回路図において
室温〜600℃、大気中VO＝一定の条件下では温度
に依存することなく常にＶが一定に保持され、セ
ンサをスモーク含有排気に晒した場合にのみＶが
変化するように配置されておれば良い。従つて、
温度補償用電極を検出用電極が形成されている基
板と異なる他の基板に形成する場合も上記の如く
配置されている限り、上記実施例と同様の効果を
奏する。
また、温度補償用電極を検出用電極に隣接する
場合も、被覆層として電気絶縁性及び耐熱性に優
れた無機質粉末を含む生シートを圧着すること、
又は被覆層として同粉末を含むペーストを印刷す
ることによつて温度補償部が外気から遮断され、
R2の変化がスモーク量に依存しないようにすれ
ば上記実施例と同様の効果を奏する。
本発明スモークセンサは、第４図に示したセン
サ回路を通常の車載用程度の検出回路と接続する
ことによつて十分検出機能を果たすものである
が、検出回路のインピーダンスが特に高い場合で
も、第５図に示すように一定抵抗R3をセンサ回
路ＡのR2と並列になるように検出回路Ｂに備え
ることによつて、検出機能を果たすことのできる
ものである。
尚、排気温度が高いために発熱体に通電しなく
ても検出部の温度が400℃以上となる条件下での
み使用する場合は、その温度で堆積したスモーク
を焼き切ることができるので、発熱体を必要とし
ない。
以上のように本発明スモークセンサを用いれば
排気温度や発熱体への通電量に依存することなく
排気中のスモーク濃度を正確に検出することがで
きる。[Table] In the above embodiment, the temperature compensation electrode was formed on the back side of the substrate on which the detection electrode was formed, but the position of the temperature compensation electrode is not limited to this. In the electrical circuit diagram shown in the figure, at room temperature to 600°C, in the atmosphere, V O = Under certain conditions, V is always held constant regardless of temperature, and V changes only when the sensor is exposed to smoke-containing exhaust gas. It would be good if it was arranged so that Therefore,
Even when the temperature compensation electrodes are formed on a substrate different from the substrate on which the detection electrodes are formed, the same effects as in the above embodiments can be achieved as long as they are arranged as described above. Also, when the temperature compensation electrode is placed adjacent to the detection electrode, a raw sheet containing an inorganic powder with excellent electrical insulation and heat resistance may be bonded as a covering layer.
Or, by printing a paste containing the same powder as a coating layer, the temperature compensation part is isolated from the outside air,
If the change in R 2 is made not to depend on the amount of smoke, the same effects as in the above embodiment can be achieved. The smoke sensor of the present invention sufficiently performs the detection function by connecting the sensor circuit shown in FIG. 4 to a normal automotive-grade detection circuit. As shown in FIG. 5, the detection function can be achieved by providing the detection circuit B with a constant resistor R 3 in parallel with R 2 of the sensor circuit A. In addition, if the exhaust temperature is high and the temperature of the detection part is 400℃ or higher even if the heating element is not energized, the temperature of the detection part will be 400℃ or higher. does not require. As described above, by using the smoke sensor of the present invention, the smoke concentration in the exhaust gas can be accurately detected without depending on the exhaust gas temperature or the amount of current applied to the heating element.
第１図は本発明スモークセンサの一実施例を示
す正面図、第２図は第１図Ａ−Ａ線断面図、第３
図は第１図及び第２図で示したスモークセンサの
製作工程の一例を示す斜視図、第４図は本発明ス
モークセンサの回路図、第５図は本発明スモーク
センサに一定抵抗R3を接続したところを示す回
路図である。
１，８，１２……基板、２ａ，２ｂ……検出用
電極、３……検出部、５……温度補償用電極、７
……被覆板。
FIG. 1 is a front view showing an embodiment of the smoke sensor of the present invention, FIG. 2 is a sectional view taken along line A-A in FIG. 1, and FIG.
The figure is a perspective view showing an example of the manufacturing process of the smoke sensor shown in FIGS. 1 and 2, FIG. 4 is a circuit diagram of the smoke sensor of the present invention, and FIG. 5 is a constant resistance R 3 in the smoke sensor of the present invention. FIG. 3 is a circuit diagram showing connections. 1, 8, 12...Substrate, 2a, 2b...Detection electrode, 3...Detection section, 5...Temperature compensation electrode, 7
...Covering board.
Claims (1)
上の基板からなる多層基板において、基板の表面
に電極間を検出部とする一対の検出用電極が形成
され、前記表面の前記電極と異なる部分、前記基
板の裏面又は前記基板と異なる他の基板の表面に
電極間を温度補償部とする一対の温度補償用電極
が形成され、前記検出部及び前記温度補償部の近
傍に発熱体を形成し、該発熱体により前記検出部
を400℃以上で且つ600℃以下に加熱し、前記検出
部を含む面及び温度補償部を含め、少なくとも検
出部を除く全面に気密な絶縁物質からなる被覆層
を設けることによつて検出部を露出させているこ
とを特徴とするスモーク濃度センサ。1. In a heat-resistant and electrically insulating substrate or a multilayer substrate consisting of two or more substrates, a pair of detection electrodes is formed on the surface of the substrate, with a detection portion between the electrodes, and a portion of the surface different from the electrodes, A pair of temperature compensation electrodes are formed on the back surface of the substrate or the surface of another substrate different from the substrate, and a temperature compensation section is formed between the electrodes, and a heating element is formed near the detection section and the temperature compensation section, The detection section is heated to 400° C. or higher and 600° C. or lower by the heating element, and a coating layer made of an airtight insulating material is provided on the entire surface including the detection section and the temperature compensation section, at least excluding the detection section. A smoke concentration sensor characterized in that a detection part is exposed.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP10977083A JPS601546A (en) | 1983-06-17 | 1983-06-17 | Smoke sensor |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP10977083A JPS601546A (en) | 1983-06-17 | 1983-06-17 | Smoke sensor |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS601546A JPS601546A (en) | 1985-01-07 |
| JPH0248055B2 true JPH0248055B2 (en) | 1990-10-23 |
Family
ID=14518784
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP10977083A Granted JPS601546A (en) | 1983-06-17 | 1983-06-17 | Smoke sensor |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS601546A (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2008547032A (en) * | 2005-06-28 | 2008-12-25 | ジーメンス ヴィディーオー オートモーティヴ アクチエンゲゼルシャフト | Sensor and method of operation for detecting soot |
| JP2012150028A (en) * | 2011-01-20 | 2012-08-09 | Denso Corp | Detection device |
| WO2013030930A1 (en) * | 2011-08-29 | 2013-03-07 | トヨタ自動車株式会社 | Microparticle sensor and method for manufacturing microparticle sensor |
Families Citing this family (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP3992400B2 (en) * | 1999-05-14 | 2007-10-17 | 本田技研工業株式会社 | Coking sensor for internal combustion engine |
| JP4512658B2 (en) * | 2008-07-04 | 2010-07-28 | 日本碍子株式会社 | Particulate matter detector |
| JP2011247650A (en) | 2010-05-24 | 2011-12-08 | Denso Corp | Particulate matter detection sensor, and particulate matter detection sensor unit |
| US8928338B2 (en) * | 2010-11-17 | 2015-01-06 | Delphi Technologies, Inc. | Self diagnostics of a particulate matter sensor |
| JP6964038B2 (en) * | 2018-04-12 | 2021-11-10 | 株式会社Soken | Particulate matter detector |
| KR102125393B1 (en) * | 2018-06-15 | 2020-06-23 | 세종공업 주식회사 | Particulater matter detection sensor |
Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS57147043A (en) * | 1981-03-09 | 1982-09-10 | Nissan Motor Co Ltd | Detector for deposition amount of soot |
-
1983
- 1983-06-17 JP JP10977083A patent/JPS601546A/en active Granted
Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS57147043A (en) * | 1981-03-09 | 1982-09-10 | Nissan Motor Co Ltd | Detector for deposition amount of soot |
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2008547032A (en) * | 2005-06-28 | 2008-12-25 | ジーメンス ヴィディーオー オートモーティヴ アクチエンゲゼルシャフト | Sensor and method of operation for detecting soot |
| JP4773517B2 (en) * | 2005-06-28 | 2011-09-14 | ジーメンス ヴィディーオー オートモーティヴ アクチエンゲゼルシャフト | Sensor and method of operation for detecting soot |
| JP2012150028A (en) * | 2011-01-20 | 2012-08-09 | Denso Corp | Detection device |
| WO2013030930A1 (en) * | 2011-08-29 | 2013-03-07 | トヨタ自動車株式会社 | Microparticle sensor and method for manufacturing microparticle sensor |
| JPWO2013030930A1 (en) * | 2011-08-29 | 2015-03-23 | トヨタ自動車株式会社 | Fine particle sensor and method for producing fine particle sensor |
Also Published As
| Publication number | Publication date |
|---|---|
| JPS601546A (en) | 1985-01-07 |
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