JPH0552797A - Dielectric constant detection device - Google Patents
Dielectric constant detection deviceInfo
- Publication number
- JPH0552797A JPH0552797A JP3216840A JP21684091A JPH0552797A JP H0552797 A JPH0552797 A JP H0552797A JP 3216840 A JP3216840 A JP 3216840A JP 21684091 A JP21684091 A JP 21684091A JP H0552797 A JPH0552797 A JP H0552797A
- Authority
- JP
- Japan
- Prior art keywords
- fuel
- winding coil
- dielectric constant
- layer winding
- temperature
- 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
Landscapes
- Measurement Of Resistance Or Impedance (AREA)
- Investigating Or Analyzing Materials By The Use Of Electric Means (AREA)
Abstract
Description
【0001】[0001]
【産業上の利用分野】この発明は、燃焼器などに供給さ
れる燃料の誘電率を非接触で検知して燃料の性状を判別
する装置に関し、特に自動車等エンジンに用いられるア
ルコール混合燃料中のアルコール含有率を測定する誘電
率検知装置に関するものである。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a device for detecting the permittivity of fuel supplied to a combustor or the like in a non-contact manner to determine the property of the fuel. The present invention relates to a dielectric constant detection device for measuring alcohol content.
【0002】[0002]
【従来の技術】近年、米国や欧州などの各国で、石油の
消費量の低減と、自動車排気ガスによる大気汚染の低減
を図るため、ガソリン中にアルコールを混合した燃料が
自動車用として導入されつつある。このようなアルコー
ル混合燃料をガソリン燃料の空燃比にマッチングされた
エンジンにそのまま用いると、アルコールがガソリンに
比べ理論空燃比が小さいため空燃比がリーン化して運転
が困難となるため、アルコール混合燃料中のアルコール
含有率を検出して、この検出値に応じて空燃比、点火時
期などを調整している。2. Description of the Related Art In recent years, in countries such as the United States and Europe, in order to reduce the consumption of petroleum and the air pollution caused by automobile exhaust gas, fuel mixed with alcohol in gasoline is being introduced for automobiles. is there. If such an alcohol mixed fuel is used as it is in an engine that matches the air-fuel ratio of gasoline fuel, the stoichiometric air-fuel ratio of alcohol is smaller than that of gasoline, making the air-fuel ratio lean and making operation difficult. The alcohol content rate of is detected, and the air-fuel ratio, ignition timing, etc. are adjusted according to the detected value.
【0003】従来、上記のようなアルコール含有率の検
出にはアルコール混合燃料の誘電率を検出する方法と、
屈折率を検出する方法が主に提案されている。これらの
方法のうち本発明出願人は誘電率を検出する方法として
例えば特願平3−22488号を出願している。以下こ
の方法を図を用いて説明する。Conventionally, a method of detecting the dielectric constant of an alcohol-mixed fuel has been used to detect the alcohol content as described above,
A method of detecting the refractive index has been mainly proposed. Among these methods, the applicant of the present invention has filed, for example, Japanese Patent Application No. 3-22488 as a method for detecting the dielectric constant. This method will be described below with reference to the drawings.
【0004】図12は特願平3−22488号で示した
一実施例である。図においてCはセンサ部であり、1は
セラミック、耐油性プラスチック等の絶縁体で形成さ
れ、内部に燃料が導かれる有底の円筒状絶縁管、3はこ
の円筒状絶縁管1の内側に設けられ、その外周面が絶縁
管1の壁面と略平行で且つ絶縁管1と同軸の円筒状の導
電性電極であり、4は絶縁管1外側の前記導電性電極3
と対向する位置に巻回された単層巻コイル、4a,4b
は単層巻コイル4のリード、2は単層巻コイル4の内周
面と絶縁管1の管壁を隔てて導電性電極3の外周面との
間に形成された燃料通路、5は導電性電極3が取り付け
られ絶縁管1と燃料シール7を介して結合されて全体で
燃料容器を形成するフランジで、ここでは導電性電極3
と一体に形成された例を示しており、6は燃料通路2に
燃料を導くニップルである。FIG. 12 shows an embodiment shown in Japanese Patent Application No. 3-22488. In the figure, C is a sensor portion, 1 is a cylindrical insulating tube with a bottom, which is made of an insulator such as ceramic or oil-resistant plastic, and into which fuel is guided, and 3 is provided inside this cylindrical insulating tube 1. Is a cylindrical conductive electrode whose outer peripheral surface is substantially parallel to the wall surface of the insulating tube 1 and is coaxial with the insulating tube 1, and 4 is the conductive electrode 3 outside the insulating tube 1.
Single-layer winding coil wound at a position opposed to 4a, 4b
Is a lead of the single-layer winding coil 4, 2 is a fuel passage formed between the inner peripheral surface of the single-layer winding coil 4 and the outer peripheral surface of the conductive electrode 3 across the tube wall of the insulating tube 1, and 5 is a conductive path. With a conductive electrode 3 attached to the insulating tube 1 via a fuel seal 7 to form a fuel container as a whole, in this case the conductive electrode 3
6 shows a nipple that guides fuel to the fuel passage 2.
【0005】Bは検知回路部を示しており、10は単層
巻コイル4のリード4aに接続されて直列回路を成す直
列抵抗Rs、11はこの抵抗Rs10の両端の信号が接
続された0°位相比較器、12は位相比較器11の出力
が接続された低域通過フィルタ、13は低域フィルタ1
2の出力と位相0°に相当する所定基準電圧Vrefが
接続された比較積分器、14は比較積分器13の出力が
接続された電圧制御発振器、15は電圧制御発振器14
の出力増幅器であり、その出力は前記直列回路に接続さ
れる。16は前記電圧制御発振器14の出力周波数の分
周器である。Reference numeral B denotes a detection circuit section, 10 is a series resistor Rs which is connected to the lead 4a of the single-layer winding coil 4 to form a series circuit, and 11 is 0 ° to which signals at both ends of the resistor Rs10 are connected. A phase comparator, 12 is a low-pass filter to which the output of the phase comparator 11 is connected, and 13 is a low-pass filter 1.
2 is connected to a comparison integrator to which a predetermined reference voltage Vref corresponding to a phase of 0 ° is connected, 14 is a voltage controlled oscillator to which the output of the comparison integrator 13 is connected, and 15 is a voltage controlled oscillator 14
Output amplifier connected to the series circuit. Reference numeral 16 is a frequency divider for the output frequency of the voltage controlled oscillator 14.
【0006】次にこの装置の動作について説明する。図
12におけるセンサ部cは図3のcに示したような等価
回路で概略与えられる。図3において、Lは単層巻コイ
ル4のインダクタンス、Cfは燃料通路2中の燃料の誘
電率εに応じて変化する単層巻コイル4と導電性電極3
との間に生ずる静電容量、Csは単層巻コイル4を燃料
から保護する絶縁管1の絶縁物質を誘電体とする容量、
Cpはリード4aに寄生する浮遊容量や0°位相比較器
11の入力容量等、燃料の誘電率εとは無関係の容量で
ある。ここで、図12におけるセンサ部のリード4aに
印加する周波数を変化させると並列LC共振を示す。即
ち、このときの並列共振周波数fは次式で示される。Next, the operation of this device will be described. The sensor section c in FIG. 12 is roughly given by an equivalent circuit as shown in c of FIG. In FIG. 3, L is the inductance of the single-layer winding coil 4, and Cf is the single-layer winding coil 4 and the conductive electrode 3 that change according to the dielectric constant ε of the fuel in the fuel passage 2.
And Cs is a capacitance that uses the insulating material of the insulating tube 1 that protects the single-layer winding coil 4 from fuel as a dielectric,
Cp is a capacitance irrelevant to the permittivity ε of the fuel, such as a stray capacitance parasitic on the lead 4a and an input capacitance of the 0 ° phase comparator 11. Here, parallel LC resonance is exhibited when the frequency applied to the lead 4a of the sensor unit in FIG. 12 is changed. That is, the parallel resonance frequency f at this time is shown by the following equation.
【0007】 f=1/〔2π√{L(Cp+1/(1/Cs+1/Cf))}〕 =K/√{a+b*ε(t)} ・・・(1) ここで、K、a、bはセンサ部の形状によって決まる定
数である。例えば、絶縁管1の径や肉厚、絶縁管1の材
料の誘電率、導電性電極3と単層巻コイル4の間隔、単
層巻コイル4の自己インダクタンスなどによる。共振周
波数fは(1)式に示したように燃料の誘電率εに依存
するため、燃料の誘電率εが大なる程共振周波数は低く
なる。また、メタノールとガソリンとの任意の混合燃料
においては、メタノールの含有率に応じて、図13に示
したような共振周波数fの変化を示した。即ち、この共
振周波数fに対応する信号を検知することにより燃料の
誘電率ε、ひいてはメタノール混合燃料中のメタノール
含有率を検知できる。F = 1 / [2π√ {L (Cp + 1 / (1 / Cs + 1 / Cf))] = K / √ {a + b * ε (t)} (1) where K, a, b is a constant determined by the shape of the sensor unit. For example, it depends on the diameter and thickness of the insulating tube 1, the dielectric constant of the material of the insulating tube 1, the distance between the conductive electrode 3 and the single-layer winding coil 4, the self-inductance of the single-layer winding coil 4, and the like. Since the resonance frequency f depends on the permittivity ε of the fuel as shown in the equation (1), the resonance frequency becomes lower as the permittivity ε of the fuel increases. In addition, in an arbitrary mixed fuel of methanol and gasoline, the resonance frequency f changes as shown in FIG. 13 according to the content ratio of methanol. That is, by detecting the signal corresponding to the resonance frequency f, the permittivity ε of the fuel, and thus the methanol content in the methanol mixed fuel, can be detected.
【0008】図12における回路部Bは前記共振周波数
fを検知するように構成されており、以下この回路部B
の説明を続ける。燃料通路2にメタノール混合燃料を流
した状態で増幅器15より抵抗Rs10と単層巻コイル
4の直列回路に高周波信号が与えられ、抵抗Rs10の
両端、即ち前記直列回路に印加される高周波電圧信号
と、単層巻コイル4に印加される高周波電圧信号が位相
比較器11に入力され両者の位相が比較される。今、前
記共振周波数fと同じ周波数の高周波電圧信号が前記直
列回路に印加されたとするとセンサ部Cの、電流電圧位
相は0°となるので、抵抗Rs10の両端の高周波電圧
の位相差は0°となる。一方、前記共振周波数fより低
い周波数の高周波電圧信号が前記直列回路に印加された
とすると、センサ部Cの電流電圧位相は0°より進んで
いるので、抵抗Rs10の両端の高周波電圧の位相差は
前記直列回路に印加する高周波信号の位相を基準にする
と0°より大となる。The circuit section B in FIG. 12 is constructed so as to detect the resonance frequency f.
Continue to explain. A high frequency signal is applied from the amplifier 15 to the series circuit of the resistor Rs10 and the single-layer winding coil 4 with the methanol mixed fuel flowing in the fuel passage 2, and the high frequency voltage signal applied to both ends of the resistor Rs10, that is, the series circuit. The high frequency voltage signal applied to the single-layer winding coil 4 is input to the phase comparator 11 and the phases of the both are compared. Now, assuming that a high frequency voltage signal having the same frequency as the resonance frequency f is applied to the series circuit, the current-voltage phase of the sensor unit C becomes 0 °, so the phase difference of the high frequency voltages across the resistor Rs10 is 0 °. Becomes On the other hand, if a high-frequency voltage signal having a frequency lower than the resonance frequency f is applied to the series circuit, the current-voltage phase of the sensor unit C leads 0 °, so that the phase difference of the high-frequency voltage across the resistor Rs10 is When the phase of the high frequency signal applied to the series circuit is used as a reference, it becomes larger than 0 °.
【0009】従って、位相比較器11の出力を低域フィ
ルタ12を介して位相差に相当する直流電圧に変換し、
前記直流電圧と位相差0°に相当する直流電圧Vref
とを比較積分器12に入力して、両者の差を積分し、比
較積分器12の出力を前記直列回路に抵抗Rs10を介
して高周波信号を印加している電圧制御発振器に入力す
ることにより、位相同期ループが形成される。電圧制御
発振器13は前記位相同期ループにより、抵抗Rs10
の両端の高周波電圧信号間の位相差が0°となるように
制御するので、電圧制御発振器13の発振周波数は常に
前記並列共振周波数fとなる。よって、電圧制御発振器
12の出力周波数を分周器16を介して適当な周波数に
分周して並列共振周波数fに対応する周波数出力fou
tが得られる。また、電圧制御発振器13の発振周波数
と制御入力電圧とが一対一に対応することに注目する
と、低域通過フィルタ11の出力が電圧出力Voutと
して取り出せる。Therefore, the output of the phase comparator 11 is converted into a DC voltage corresponding to the phase difference via the low pass filter 12,
DC voltage Vref corresponding to the DC voltage and a phase difference of 0 °
Are input to the comparison integrator 12, the difference between the two is integrated, and the output of the comparison integrator 12 is input to the voltage controlled oscillator applying a high frequency signal to the series circuit via the resistor Rs10. A phase locked loop is formed. The voltage controlled oscillator 13 has a resistor Rs10 by the phase locked loop.
Since the phase difference between the high-frequency voltage signals at both ends of is controlled to be 0 °, the oscillation frequency of the voltage controlled oscillator 13 is always the parallel resonance frequency f. Therefore, the output frequency of the voltage controlled oscillator 12 is divided into an appropriate frequency via the frequency divider 16, and the frequency output foo corresponding to the parallel resonance frequency f is obtained.
t is obtained. Further, noting that the oscillation frequency of the voltage controlled oscillator 13 and the control input voltage have a one-to-one correspondence, the output of the low pass filter 11 can be taken out as the voltage output Vout.
【0010】[0010]
【発明が解決しようとする課題】しかしながらこの従来
装置では、メタノール含有率が変化しないにもかかわら
ず燃料の温度変化によって、燃料の誘電率及び絶縁管1
の誘電率が変化し、図13の一点鎖線や破線で示すよう
に周波数出力foutが大きく変化し、正確なメタノー
ル含有率の検出が困難になるといった問題点があった。However, in this conventional device, the dielectric constant of the fuel and the insulating tube 1 are changed due to the temperature change of the fuel even though the methanol content does not change.
There is a problem in that the dielectric constant of No. 1 changes and the frequency output fout greatly changes as indicated by the alternate long and short dash line in FIG. 13, making it difficult to accurately detect the methanol content.
【0011】この発明は上記のような問題点を解消する
ためになされたもので、アルコール含有燃料の温度変化
に対する誘電率検知を精度よく検知できる誘電率検知装
置を得ることを目的とする。The present invention has been made to solve the above problems, and an object of the present invention is to provide a dielectric constant detecting device capable of accurately detecting dielectric constant with respect to temperature change of alcohol-containing fuel.
【0012】[0012]
【課題を解決するための手段】この発明に係る誘電率検
知装置は、導電性電極と、導電性電極に所定間隔離して
絶縁層で覆われたコイル柱面が対向配置された単層巻コ
イルと、導電性電極と単層巻コイルとの間に燃料が導入
される燃料通路と、単層巻コイルの共振周波数を検出す
る手段を備え、共振周波数が燃料の誘電率に相当するよ
うに構成された燃料の誘電率検知装置であって、燃料の
温度変化を検知できる位置に温度補償コンデンサを設け
ると共に、単層巻コイルと並列に接続し、共振周波数の
温度特性を温度補償コンデンサによって相殺するように
したものである。SUMMARY OF THE INVENTION A dielectric constant sensing device according to the present invention is a single layer winding coil in which a conductive electrode and a coil pillar surface which is separated from the conductive electrode by a predetermined distance and is covered with an insulating layer are arranged to face each other. And a fuel passage through which fuel is introduced between the conductive electrode and the single-layer winding coil, and means for detecting the resonance frequency of the single-layer winding coil. The resonance frequency corresponds to the dielectric constant of the fuel. A device for detecting the permittivity of fuel, which is provided with a temperature compensating capacitor at a position where the temperature change of the fuel can be detected, and is connected in parallel with the single-layer winding coil to cancel the temperature characteristic of the resonance frequency by the temperature compensating capacitor. It was done like this.
【0013】[0013]
【作用】この発明における誘電率検知装置は、燃料の誘
電率を共振周波数により測定すると共に、温度補償コン
デンサにより、温度による共振周波数の変化を相殺し、
装置の温度変化にかかわらず常に正確なメタノール含有
率を検出するものである。In the dielectric constant detecting device according to the present invention, the dielectric constant of the fuel is measured by the resonance frequency, and the temperature compensation capacitor cancels the change in the resonance frequency due to the temperature.
It always detects an accurate methanol content regardless of the temperature change of the device.
【0014】[0014]
【実施例】以下、この発明の係る誘電率検知装置の一実
施例を図とともに詳細に説明する。図1はこの発明に係
る燃料の誘電率検知装置の一実施例を示す構成図、図2
はこの一実施例のセンサ部の構造図、図3及び図4はセ
ンサ部の等価回路図とその構成図、図5は具体的回路例
を用いた実施例での出力特性図、図6は温度に対する燃
料の誘電率特性図、図7及び図8は温度に対する各種静
電容量特性図、図9は温度に対する従来例と実施例の並
列共振周波数特性図である。DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the dielectric constant detecting device according to the present invention will be described in detail below with reference to the drawings. FIG. 1 is a configuration diagram showing an embodiment of a fuel dielectric constant detecting device according to the present invention, FIG.
Is a structural diagram of the sensor portion of this embodiment, FIGS. 3 and 4 are equivalent circuit diagrams and configuration diagrams of the sensor portion, FIG. 5 is an output characteristic diagram of an embodiment using a concrete circuit example, and FIG. FIG. 7 and FIG. 8 are various capacitance characteristic diagrams with respect to temperature, and FIG. 9 is a parallel resonance frequency characteristic diagram of the conventional example and the example with respect to temperature.
【0015】図において、検出回路は従来例と同一であ
るがセンサ部Aが異っているので、センサ部Aについて
説明する。1はセラミック、耐油性プラスチック等の絶
縁体で形成され内部に燃料が導かれる有底円筒状絶縁
管、3はこの円筒状絶縁管1の内側に設けられ、絶縁管
1の外周面が絶縁管1の壁面と略平行でかつ絶縁管1と
同軸の円筒状の導電性電極で、チタン、ステンレス、表
面がアルマイト処理されたアルミニウム等が燃料に対す
る耐性上好ましい。4は絶縁管1の外側の導電性電極3
と対向する位置に巻回された単層巻コイル、4a,4b
は単層巻コイル4のリード、2は単層巻コイル4の内周
面と絶縁管1の管壁を隔てて導電性電極3の外周面との
間に形成された燃料通路、5は導電性電極3が取り付け
られた絶縁管1と燃料シール7を介して結合されて全体
で燃料容器を形成するフランジで、ここでは導電性電極
3が一体に形成された例を示しており、6は燃料通路2
に燃料を導くニップル、9は燃料温度が検知できる位置
に設けると共に単層巻コイル4に並列に接続された温度
補償コンデンサである。In the figure, the detection circuit is the same as that of the conventional example, but the sensor section A is different. Therefore, the sensor section A will be described. Reference numeral 1 denotes a bottomed cylindrical insulating tube made of an insulator such as ceramic or oil-resistant plastic, into which fuel is guided, and 3 is provided inside the cylindrical insulating tube 1, and the outer peripheral surface of the insulating tube 1 is an insulating tube. 1 is a cylindrical conductive electrode substantially parallel to the wall surface of 1 and coaxial with the insulating tube 1. Titanium, stainless steel, aluminum whose surface is anodized, or the like is preferable in terms of resistance to fuel. 4 is a conductive electrode 3 outside the insulating tube 1.
Single-layer winding coil wound at a position opposed to 4a, 4b
Is a lead of the single-layer winding coil 4, 2 is a fuel passage formed between the inner peripheral surface of the single-layer winding coil 4 and the outer peripheral surface of the conductive electrode 3 across the tube wall of the insulating tube 1, and 5 is a conductive path. A flange that is connected to an insulating tube 1 to which a conductive electrode 3 is attached via a fuel seal 7 to form a fuel container as a whole. Here, an example in which the conductive electrode 3 is integrally formed is shown. Fuel passage 2
A nipple 9 for guiding the fuel to is provided at a position where the fuel temperature can be detected, and a temperature compensating capacitor connected in parallel to the single-layer winding coil 4.
【0016】図3及び図4はセンサ部Aを簡易的にあら
わした等価回路図とその構成図で、Cpは単層巻コイル
4に生ずる線間容量及び入力容量、Csは単層巻コイル
4を燃料から保護する絶縁管1の絶縁物質を誘電体とす
る容量、Cfは燃料の誘電体とする容量、Ctは温度補
償コンデンサの容量とすると、並列共振周波数fは次式
で表される。3 and 4 are an equivalent circuit diagram and a configuration diagram showing the sensor section A in a simple manner. Cp is a line capacitance and an input capacitance generated in the single-layer winding coil 4, and Cs is a single-layer winding coil 4. The parallel resonance frequency f is represented by the following equation, where Cf is a capacity of a fuel dielectric and Ct is a capacity of a temperature compensation capacitor.
【0017】 f=1/〔2 π√{L(Ct(t)+Cp+1/(1/Cs(t)+1/Cf( ε,t)))}〕・・・(2) 並列共振周波数fは燃料の誘電率εに依存し、誘電率ε
が大なるほど低下する。しかも図6に示すように、燃料
の誘電率εは燃料の温度変化に依存し温度上昇とともに
単調減少する。F = 1 / [2π√ {L (Ct (t) + Cp + 1 / (1 / Cs (t) + 1 / Cf (ε, t)))}] ... (2) Parallel The resonance frequency f depends on the permittivity ε of the fuel, and the permittivity ε
Becomes larger, it decreases. Moreover, as shown in FIG. 6, the permittivity ε of the fuel depends on the temperature change of the fuel, and monotonously decreases as the temperature rises.
【0018】次に、上記(2)式について、センサ部の
温度依存性を示す直列合成容量は、次式となる。Next, with respect to the above equation (2), the series combined capacitance showing the temperature dependence of the sensor portion is given by the following equation.
【0019】 1/C(t)=1/Cs(t)+1/Cf(t) =a/εs(t)+b/εf(t) ・・・(3) ここで、a,bは絶縁体の材質及びセンサ形状によって
決まるもので、aはCsの幾何容量、bはCfの幾何容
量であり、単に誘電率の変化で決まるものではなく、そ
れぞれの幾何容量が係数としてかかってくる。燃料の誘
電率は温度と共に単調減少し、逆に絶縁体の誘電率は温
度と共に単調増加するため、これらの誘電率の対応する
静電容量の直列接続では温度依存性は打ち消される方向
となる。燃料の誘電率の温度に対する影響は燃料の含有
率によって多少異なった温度係数を示すが、絶縁体によ
る温度係数の影響が大きい。センサ形状を固定し、絶縁
体を変更した場合の温度特性を直列合成容量の形で、図
7及び図8に示した。ここで、図7及び図8の違いは絶
縁体が変わったときの様子を示したもので、aはナイロ
ン、bはPPSである。Csは前述のように絶縁体の材
質によりバラツクものであるが、耐油性を考慮すると絶
縁体の材質の選択にも限界がある。このとき、燃料温度
が検知できる位置に温度補償コンデンサを設けて単層巻
コイルに並列に接続した場合の合成容量は、次式とな
る。1 / C (t) = 1 / Cs (t) + 1 / Cf (t) = a / εs (t) + b / εf (t) (3) where a and b are insulators A is a geometric capacitance of Cs, b is a geometric capacitance of Cf, and is not simply determined by a change in the dielectric constant, but each geometric capacitance acts as a coefficient. Since the permittivity of fuel monotonically decreases with temperature, and conversely, the permittivity of insulator monotonically increases with temperature, the temperature dependence tends to be canceled in the series connection of the corresponding capacitances of these permittivities. The influence of the permittivity of the fuel on the temperature shows a slightly different temperature coefficient depending on the fuel content, but the influence of the temperature coefficient of the insulator is large. The temperature characteristics when the sensor shape is fixed and the insulator is changed are shown in FIGS. 7 and 8 in the form of series combined capacitance. Here, the difference between FIG. 7 and FIG. 8 shows the state when the insulator is changed, where a is nylon and b is PPS. Although Cs varies depending on the material of the insulator as described above, there is a limit to the selection of the material of the insulator in consideration of oil resistance. At this time, when a temperature compensation capacitor is provided at a position where the fuel temperature can be detected and the temperature compensation capacitor is connected in parallel to the single-layer winding coil, the combined capacity is given by the following equation.
【0020】 C=Ct(t)+1/(1/Cs(t)+1/Cf(t)) ・・・(4) センサの材質と形状、すなわち幾何容量の値が決定した
段階で、上記(4)式が温度によらない関数となるよう
温度補償コンデンサの容量及び温度係数、温度係数許容
差を決定する。また、以上の結果より並列共振周波数の
温度特性を従来例と比較したものを図9に示した。この
ように従来例に比べ並列共振周波数の温度特性が補償さ
れるものである。C = Ct (t) + 1 / (1 / Cs (t) + 1 / Cf (t)) (4) At the stage when the material and shape of the sensor, that is, the value of the geometrical capacitance is determined, the above ( The capacity and temperature coefficient of the temperature compensation capacitor and the temperature coefficient tolerance are determined so that the equation 4) becomes a function independent of temperature. From the above results, FIG. 9 shows a comparison of the temperature characteristic of the parallel resonance frequency with that of the conventional example. Thus, the temperature characteristic of the parallel resonance frequency is compensated for as compared with the conventional example.
【0021】図5は従来例と同様図12の検知回路によ
って、前記図1のかかる装置の実施例のアルコール混合
ガソリンにおけるアルコール含有率に対する周波数出力
foutを概略示したもので、メタノール含有率が増加
し、誘電率εが大となるとともに燃料の温度変化によら
ず単調に出力が低下する特性になる。FIG. 5 schematically shows the frequency output fout with respect to the alcohol content rate in the alcohol blended gasoline of the embodiment of the apparatus of FIG. 1 by the detection circuit of FIG. 12 as in the conventional example, in which the methanol content rate increases. However, the dielectric constant ε becomes large and the output monotonously decreases regardless of the temperature change of the fuel.
【0022】上記実施例ではセンサ部Aの単層巻コイル
と導電性電極が同軸の例を示したが、必ずしも同軸でな
く、単層巻コイルと導電性電極の間に燃料による静電容
量が存在するようにすればよい。In the above embodiment, the single layer winding coil of the sensor portion A and the conductive electrode are coaxial, but they are not necessarily coaxial, and the electrostatic capacitance due to the fuel is present between the single layer winding coil and the conductive electrode. Just make it exist.
【0023】また図10はこの発明の他の実施例を示す
もので、温度補償コンデンサ9を、単層巻コイル4を燃
料から保護するための絶縁層の中にモールドすると共
に、温度補償コンデンサ9の端子を単層巻コイル4端子
近傍で接続したものである。かかる構造では温度補償コ
ンデンサ9のリード等の付加容量が小さくでき、補償が
より正確になる効果がある。さらに図11のように単層
巻コイル4と導電性電極3の配置を逆にし、単層巻コイ
ル4を絶縁管1でモールドすると共に温度補償コンデン
サ9も絶縁管1でモールドし、絶縁管内で端子を接続す
ることで、単層巻コイル共々外乱より保護できる効果が
ある。FIG. 10 shows another embodiment of the present invention, in which the temperature compensating capacitor 9 is molded in an insulating layer for protecting the single-layer winding coil 4 from the fuel, and the temperature compensating capacitor 9 is used. The terminals are connected near the four terminals of the single-layer winding coil. With such a structure, the additional capacitance such as the lead of the temperature compensating capacitor 9 can be reduced, and the effect is that the compensation becomes more accurate. Further, as shown in FIG. 11, the arrangement of the single-layer winding coil 4 and the conductive electrode 3 is reversed, and the single-layer winding coil 4 is molded with the insulating tube 1 and the temperature compensation capacitor 9 is also molded with the insulating tube 1, and inside the insulating tube. By connecting the terminals, the single-layer winding coil can be effectively protected from disturbance.
【0024】なお、上記実施例では本装置をメタノール
燃料中のメタノール含有率の検知に用いた場合を示した
が、他の液体中の誘電率検出用として広く適用が可能で
ある。In the above-mentioned embodiment, the case where the present apparatus is used for detecting the methanol content in the methanol fuel is shown, but it can be widely applied for detecting the dielectric constant in other liquids.
【0025】[0025]
【発明の効果】以上説明したようにこの発明によれば、
燃料通路の途中に燃料を挟んで導電性電極と絶縁層で覆
われた単層巻コイルを設け、単層巻コイルと並列に温度
補償コンデンサを接続し、燃料温度変化による共振周波
数を補償したため、常に精度よくアルコール含有率を検
知できる。As described above, according to the present invention,
A single-layer winding coil covered with a conductive electrode and an insulating layer was provided in the middle of the fuel passage with a fuel sandwiched between them, and a temperature compensation capacitor was connected in parallel with the single-layer winding coil to compensate for the resonance frequency due to fuel temperature changes. The alcohol content can always be detected accurately.
【図1】この発明による燃料の誘電率検知装置の一実施
例を示す構成図である。FIG. 1 is a configuration diagram showing an embodiment of a fuel dielectric constant detection device according to the present invention.
【図2】この発明の一実施例のセンサ部の一部破断斜視
図である。FIG. 2 is a partially cutaway perspective view of a sensor unit according to an embodiment of the present invention.
【図3】この発明の一実施例のセンサ部の等価回路図で
ある。FIG. 3 is an equivalent circuit diagram of a sensor unit according to an embodiment of the present invention.
【図4】この発明の一実施例のセンサ部の等価回路の構
成図である。FIG. 4 is a configuration diagram of an equivalent circuit of a sensor unit according to an embodiment of the present invention.
【図5】この発明における具体的回路例での出力特性図
である。FIG. 5 is an output characteristic diagram of a specific circuit example according to the present invention.
【図6】この発明における温度に対する燃料の誘電率特
性図である。FIG. 6 is a dielectric constant characteristic diagram of fuel with respect to temperature in the present invention.
【図7】温度に対する各種静電容量特性図である。FIG. 7 is a capacitance characteristic diagram with respect to temperature.
【図8】温度に対する各種静電容量特性図である。FIG. 8 is a capacitance characteristic diagram with respect to temperature.
【図9】温度に対する従来例と実施例の並列共振周波数
特性図である。FIG. 9 is a parallel resonance frequency characteristic diagram of a conventional example and an example with respect to temperature.
【図10】この発明の他の実施例の誘電率検知装置のセ
ンサ部の構成図である。FIG. 10 is a configuration diagram of a sensor unit of a dielectric constant detection device according to another embodiment of the present invention.
【図11】この発明のさらに他の実施例の誘電率検知装
置のセンサ部の構成図である。FIG. 11 is a configuration diagram of a sensor unit of a dielectric constant detection device according to still another embodiment of the present invention.
【図12】従来の燃料の誘電率検知装置を示す構成図で
ある。FIG. 12 is a configuration diagram showing a conventional fuel dielectric constant detection device.
【図13】従来の誘電率検知装置での出力特性図であ
る。FIG. 13 is an output characteristic diagram of a conventional dielectric constant detection device.
1 絶縁管 2 燃料通路 3 導電性電極 4 単層巻コイル 4a,4b リード 9 温度補償コンデンサ 10 直列抵抗Rs 11 0°位相比較器 12 低域通過フィルタ 13 比較積分器 14 電圧制御発振器 15 増幅器 16 分周器 DESCRIPTION OF SYMBOLS 1 Insulation tube 2 Fuel passage 3 Conductive electrode 4 Single layer winding coil 4a, 4b Lead 9 Temperature compensation capacitor 10 Series resistance Rs 11 0 ° Phase comparator 12 Low pass filter 13 Comparator / integrator 14 Voltage controlled oscillator 15 Amplifier 16 minutes Circulator
Claims (1)
隔離して絶縁層で覆われたコイル柱面が対向配置された
単層巻コイルと、前記導電性電極と前記単層巻コイルと
の間に燃料が導入される燃料通路と、前記単層巻コイル
の共振周波数を検出する手段を備え、前記共振周波数が
燃料の誘電率に相当するように構成された燃料の誘電率
検知装置であって、燃料の温度変化を検知できる位置に
温度補償コンデンサを設けると共に、前記単層巻コイル
と並列に接続し、前記共振周波数の温度特性を前記温度
補償コンデンサによって相殺するようにしたことを特徴
とする誘電率検知装置。1. A conductive electrode, a single-layer winding coil in which a coil pillar surface which is isolated from the conductive electrode by a predetermined distance and is covered with an insulating layer is arranged to face the conductive electrode, and the conductive electrode and the single-layer winding coil. A fuel dielectric constant detection device having a fuel passage through which fuel is introduced, and means for detecting the resonance frequency of the single-layer winding coil, wherein the resonance frequency corresponds to the dielectric constant of the fuel. Therefore, a temperature compensation capacitor is provided at a position where the temperature change of the fuel can be detected, and it is connected in parallel with the single-layer winding coil so that the temperature characteristic of the resonance frequency is canceled by the temperature compensation capacitor. Permittivity detector.
Priority Applications (5)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP3216840A JPH0552797A (en) | 1991-08-28 | 1991-08-28 | Dielectric constant detection device |
KR1019920014786A KR960010689B1 (en) | 1991-08-28 | 1992-08-17 | Sensor |
DE4228737A DE4228737C2 (en) | 1991-08-28 | 1992-08-28 | Device for determining the dielectric constant of fuel |
US08/279,550 US5543722A (en) | 1991-08-28 | 1994-07-25 | Channel forming fuel permittivity sensor with automatic temperature compensation |
US08/487,515 US5592098A (en) | 1991-08-28 | 1995-06-07 | Channel forming fuel permittivity sensor with automatic temperature compensation |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP3216840A JPH0552797A (en) | 1991-08-28 | 1991-08-28 | Dielectric constant detection device |
Publications (1)
Publication Number | Publication Date |
---|---|
JPH0552797A true JPH0552797A (en) | 1993-03-02 |
Family
ID=16694727
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
JP3216840A Pending JPH0552797A (en) | 1991-08-28 | 1991-08-28 | Dielectric constant detection device |
Country Status (1)
Country | Link |
---|---|
JP (1) | JPH0552797A (en) |
Cited By (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2003532080A (en) * | 2000-04-20 | 2003-10-28 | ミレニウム センサーズ リミテッド | Windshield dual moisture sensor |
JP2018128472A (en) * | 2018-05-23 | 2018-08-16 | シーエル計測工業株式会社 | Object detection sensor |
JP2018128474A (en) * | 2018-05-23 | 2018-08-16 | シーエル計測工業株式会社 | Object detection sensor |
JP2018128473A (en) * | 2018-05-23 | 2018-08-16 | シーエル計測工業株式会社 | Object detection sensor |
JP2018146592A (en) * | 2018-05-23 | 2018-09-20 | シーエル計測工業株式会社 | Object detection sensor |
-
1991
- 1991-08-28 JP JP3216840A patent/JPH0552797A/en active Pending
Cited By (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2003532080A (en) * | 2000-04-20 | 2003-10-28 | ミレニウム センサーズ リミテッド | Windshield dual moisture sensor |
JP2018128472A (en) * | 2018-05-23 | 2018-08-16 | シーエル計測工業株式会社 | Object detection sensor |
JP2018128474A (en) * | 2018-05-23 | 2018-08-16 | シーエル計測工業株式会社 | Object detection sensor |
JP2018128473A (en) * | 2018-05-23 | 2018-08-16 | シーエル計測工業株式会社 | Object detection sensor |
JP2018146592A (en) * | 2018-05-23 | 2018-09-20 | シーエル計測工業株式会社 | Object detection sensor |
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