JPH0520979Y2 - - Google Patents
Info
- Publication number
- JPH0520979Y2 JPH0520979Y2 JP4388986U JP4388986U JPH0520979Y2 JP H0520979 Y2 JPH0520979 Y2 JP H0520979Y2 JP 4388986 U JP4388986 U JP 4388986U JP 4388986 U JP4388986 U JP 4388986U JP H0520979 Y2 JPH0520979 Y2 JP H0520979Y2
- Authority
- JP
- Japan
- Prior art keywords
- flow rate
- bridge circuit
- temperature
- voltage
- resistor
- 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
- 239000012530 fluid Substances 0.000 claims description 15
- 238000010586 diagram Methods 0.000 description 3
- 230000007423 decrease Effects 0.000 description 2
- BASFCYQUMIYNBI-UHFFFAOYSA-N platinum Chemical compound [Pt] BASFCYQUMIYNBI-UHFFFAOYSA-N 0.000 description 2
- 238000006243 chemical reaction Methods 0.000 description 1
- 238000002485 combustion reaction Methods 0.000 description 1
- 229910052697 platinum Inorganic materials 0.000 description 1
- 230000035945 sensitivity Effects 0.000 description 1
Landscapes
- Details Of Flowmeters (AREA)
- Measuring Volume Flow (AREA)
Description
【考案の詳細な説明】
〈産業上の利用分野〉
本考案は、感度抵抗を利用した感温式流量測定
装置に関する。[Detailed Description of the Invention] <Industrial Application Field> The present invention relates to a temperature-sensitive flow rate measuring device using a sensitive resistor.
〈従来の技術〉
この種の感温式流量測定装置は、自動車用内燃
機関において吸入空気流量を測定するもの等に使
用され、例えば第３図に示すようなものがある
（実開昭59−78926号参照）。<Prior art> This type of temperature-sensitive flow rate measuring device is used to measure the intake air flow rate in internal combustion engines for automobiles, and there is, for example, one shown in Fig. (See No. 78926).
図を参照して概要を説明すると、機関の吸気通
路中に配設される白金からなる感温抵抗RHと抵
抗RK，R1，R2，R3とによりブリツジ回路が形成
され、このブリツジ回路へバツテリＢから抵抗
R4を介して供給される電流は、抵抗R2の端子電
圧と抵抗R3の端子電圧との差、即ちブリツジ回
路の非平衡電圧に基づき、差動増幅器OP及びト
ランジスタTrを介して制御されるようになつて
いる。例えば吸入空気流量が増大すると、感度抵
抗PHがより冷却されることによりその抵抗値が
減少するが、このとき抵抗R3の端子電圧が増大
して差動増幅器OPの出力が低下し、トランジス
タTrのベース電流が増大してコレクタ電流が増
大するため、ブリツジ回路への供給電流Ｉが増大
する。つまり、流量の変化に対し、感温抵抗RH
の端子電圧を一定に保つように供給電流を変化さ
せ、抵抗R3の端子電圧UmをＡ／Ｄ（アナログ・
デジタル）変換器１を介してマイクロコンピユー
タ２に入力させ、マイクロコンピユータ２により
端子電圧Umに対応する流量を演算して測定する
ようにしている。 To explain the outline with reference to the figure, a bridge circuit is formed by a temperature-sensitive resistor R H made of platinum and resistors R K , R 1 , R 2 , and R 3 arranged in the intake passage of the engine. Resistor from battery B to bridge circuit
The current supplied via R4 is controlled via the differential amplifier OP and the transistor Tr based on the difference between the terminal voltage of the resistor R2 and the terminal voltage of the resistor R3 , that is, the unbalanced voltage of the bridge circuit. It is becoming more and more common. For example, when the intake air flow rate increases, the sensitivity resistor P H is cooled further and its resistance value decreases, but at this time, the terminal voltage of the resistor R 3 increases and the output of the differential amplifier O P decreases. Since the base current of the transistor Tr increases and the collector current increases, the current I supplied to the bridge circuit increases. In other words, the temperature-sensitive resistance R H
The supply current is changed to keep the terminal voltage of resistor R3 constant, and the terminal voltage Um of resistor R3 is changed by A/D (analog).
The flow rate corresponding to the terminal voltage Um is calculated and measured by the microcomputer 2 through the digital) converter 1.
また、この種の感温式流量測定装置において
は、感温抵抗RHと共に吸気通路中に配置した温
度補償抵抗RKによつて吸入空気流量の温度変化
による流量特性の変動を補償する一方、エンジン
ルーム側に配置した他の抵抗R1，R2，R3の抵抗
温度係数α1〜α3を適当に選ぶことにより、エンジ
ンルーム内の温度変化による流量特性の変動を補
償するようにしている。 In addition, in this type of temperature-sensitive flow rate measuring device, fluctuations in the flow rate characteristics due to temperature changes in the intake air flow rate are compensated for by a temperature-compensating resistor RK placed in the intake passage along with a temperature-sensitive resistor RH . By appropriately selecting the resistance temperature coefficients α 1 to α 3 of the other resistors R 1 , R 2 , and R 3 placed on the engine room side, fluctuations in flow characteristics due to temperature changes in the engine room can be compensated for. There is.
具体的には、温度変化があつてもブリツジ回路
の非平衡電圧を一定に保つようにしているわけで
ある。 Specifically, the unbalanced voltage of the bridge circuit is kept constant even when the temperature changes.
〈考案が解決しようとする問題点〉
しかしながら、このようにしてブリツジ回路の
非平衡電圧を一定に保つようにしても、ブリツジ
回路への供給電流Ｉは一定に保てるが、流体流量
（吸入空気流量）として取り出される抵抗R3の端
子電圧Umは、エンジンルーム温度がΔT変化す
ると、Um＝R3（１＋α・ΔT）・Ｉとなるため
R3・α・ΔTの誤差を生じる（αは抵抗R3の抵抗
温度係数）。<Problems to be solved by the invention> However, even if the unbalanced voltage of the bridge circuit is kept constant in this way, the supply current I to the bridge circuit can be kept constant, but the fluid flow rate (intake air flow rate ), the terminal voltage Um of the resistor R3 , which is taken out as
This causes an error of R3・α・ΔT (α is the temperature coefficient of resistance of resistor R3 ).
本考案は、上記の従来の実状に鑑みなされたも
ので、温度変化による流体流量の測定誤差を可及
的に減少できるようにした感温式流量測定装置を
提供することを目的とする。 The present invention was developed in view of the above-mentioned conventional situation, and an object of the present invention is to provide a temperature-sensitive flow rate measuring device that can reduce as much as possible errors in measuring fluid flow rate due to temperature changes.
〈問題点を解決するための手段〉
このため、本考案は、流体通路中に配置した感
温抵抗と複数の抵抗とにより形成したブリツジ回
路と、前記感温抵抗の流体流量に応じた抵抗値の
変化により変化するブリツジ回路の非平衡電圧に
基づいてブリツジ回路への供給電流を制御する制
御回路とを備え、前記供給電流に対応する流体流
量を測定すると共に、ブリツジ回路を形成する各
抵抗の抵抗温度係数特性を周辺温度変化に対して
ブリツジ回路の非平衡電圧を略一定に保つように
設定してなる感温式流量測定装置において、前記
ブリツジ回路の非平衡電圧を増幅する増幅回路を
設け、該増幅回路の出力電圧に基づいて流体流量
を測定するように構成する。<Means for Solving the Problems> For this reason, the present invention provides a bridge circuit formed by a temperature-sensitive resistor and a plurality of resistors arranged in a fluid passage, and a resistance value of the temperature-sensitive resistor depending on the fluid flow rate. a control circuit that controls the supply current to the bridge circuit based on the unbalanced voltage of the bridge circuit that changes due to changes in the bridge circuit, and measures the fluid flow rate corresponding to the supply current, and also measures the fluid flow rate of each resistor forming the bridge circuit. In a temperature-sensitive flow rate measuring device in which the resistance temperature coefficient characteristic is set to keep the non-balanced voltage of the bridge circuit substantially constant against changes in ambient temperature, an amplifier circuit is provided to amplify the non-balanced voltage of the bridge circuit. , configured to measure fluid flow rate based on the output voltage of the amplifier circuit.
かかる構成において、ブリジツ回路を形成する
抵抗の抵抗値が、周囲温度の変化により変化した
場合でも、各抵抗の抵抗温度係数の設定によりブ
リツジ回路の非平衡電圧は周囲温度変化には影響
されず略一定に保たれている。したがつて、ブリ
ツジ回路の非平衡電圧は流体流量のみにより一義
的に定まる。但し、非平衡電圧は微小値であるた
め、これを増幅回路によつて増幅し、増幅された
電圧に基づいて流体流量が測定される。 In such a configuration, even if the resistance values of the resistors forming the bridge circuit change due to changes in ambient temperature, the unbalanced voltage of the bridge circuit will not be affected by changes in ambient temperature due to the setting of the resistance temperature coefficient of each resistor. is kept constant. Therefore, the unbalanced voltage of the bridge circuit is uniquely determined only by the fluid flow rate. However, since the unbalanced voltage is a minute value, it is amplified by an amplifier circuit, and the fluid flow rate is measured based on the amplified voltage.
この結果、ブリツジ回路の周辺温度に影響され
ることなく、流体流量を可及的に高制度に測定で
きる。 As a result, the fluid flow rate can be measured with as high precision as possible without being affected by the ambient temperature of the bridge circuit.
〈実施例〉
以下、本考案の実施例を図面に基づいて説明す
る。<Example> Hereinafter, an example of the present invention will be described based on the drawings.
一実施例を示す第１図において、感温抵抗RH
と抵抗RK，R1，R2，R3とからなるブリツジ回路
と、バツテリＢ、抵抗R4、差動増幅器OP及びト
ランジスタTrからなる制御回路の構成は従来同
様である。 In FIG. 1 showing one embodiment, temperature-sensitive resistor R H
The configuration of the bridge circuit consisting of the resistors R K , R 1 , R 2 and R 3 and the control circuit consisting of the battery B, the resistor R 4 , the differential amplifier OP and the transistor Tr is the same as the conventional one.
次に、本考案にかかる部分の構成を説明する。 Next, the configuration of the parts according to the present invention will be explained.
前記差動増幅器OPに抵抗R5，R6を介して入力
されるブリツジ回路の非平衡電圧ΔVが抵抗R11，
R12を介して第２の差動増幅器OP1にも入力され
る。該差動増幅器OP1と入力抵抗R11，R12，R13
及び帰還抵抗R14が本考案に係る増幅回路を構成
する。 The unbalanced voltage ΔV of the bridge circuit inputted to the differential amplifier OP via the resistors R 5 and R 6 is connected to the resistors R 11 ,
It is also input to the second differential amplifier O P1 via R12 . The differential amplifier O P1 and input resistances R 11 , R 12 , R 13
and feedback resistor R14 constitute an amplifier circuit according to the present invention.
前記差動増幅器OP1により非平衡電圧ΔVを増
幅した出力電圧Vsは、Ａ／Ｄ変換器１１に入力
されてAS／Ｄ変換され、そのデジタル信号がマ
イクロコンピユータ１２に入力される。 The output voltage Vs obtained by amplifying the unbalanced voltage ΔV by the differential amplifier O P1 is input to the A/D converter 11 and subjected to AS/D conversion, and the digital signal thereof is input to the microcomputer 12.
マイクロコンピユータ１２は、出力電圧Vsの
デジタル値に対応する吸入空気流量を演算して測
定するようになつている。 The microcomputer 12 is configured to calculate and measure the intake air flow rate corresponding to the digital value of the output voltage Vs.
ここにおいて、制御回路は従来例で説明したよ
うに、吸入空気流量の変化に対して感温抵抗RH
の抵抗値を一定に保つように制御する。換言すれ
ば、流量が増大する程ブリツジ回路への供給電流
Ｉを増大するように制御され、そのために非平衡
電圧ΔVは増大する。 Here, as explained in the conventional example, the control circuit uses a temperature-sensitive resistor R H to respond to changes in the intake air flow rate.
control to keep the resistance value constant. In other words, as the flow rate increases, the current I supplied to the bridge circuit is controlled to increase, and therefore the unbalanced voltage ΔV increases.
このように、吸入空気流量Ｑに対して非平衡電
圧ΔVは第２図に示すように一義的に定まり、し
かも抵抗R1，R2，R3はエンジンルームの温度変
化に対して非平衡電圧Ｖを略一定に保つように設
定されているため、温度変化に影響されることな
く吸入空気流量Ｑを高制度に測定できるのであ
る。 In this way, the non-equilibrium voltage ΔV with respect to the intake air flow rate Q is uniquely determined as shown in Figure 2, and the resistances R 1 , R 2 , and R 3 change the non-equilibrium voltage with respect to engine room temperature changes. Since V is set to be kept substantially constant, the intake air flow rate Q can be measured with high accuracy without being affected by temperature changes.
〈考案の効果〉
以上説明したように、本考案によれば、流体流
量を温度変化に影響されることなく可及的に高制
度に測定できるという効果が得られる。<Effects of the Invention> As explained above, according to the present invention, it is possible to obtain the effect that the fluid flow rate can be measured with as high precision as possible without being affected by temperature changes.
第１図は本考案の一実施例を示す回路図、第２
図は非平衡電圧に対する吸入空気流量特性を示す
線図、第３図は従来例を示す回路図である。
１１……Ａ／Ｄ変換器、１２……マイクロコン
ピユータ、OP……差動増幅器（制御回路用）、
OP1……差動増幅器（増幅回路用）、R1，R2，R3，
RK……抵抗（ブリツジ回路用）、RH……感温抵
抗、R11，R12，R13，R14……抵抗（増幅回路
用）、Tr……トランジスタ、Ｂ……バツテリ。
Figure 1 is a circuit diagram showing one embodiment of the present invention;
The figure is a diagram showing intake air flow rate characteristics with respect to unbalanced voltage, and FIG. 3 is a circuit diagram showing a conventional example. 11...A/D converter, 12...Microcomputer, O P ...Differential amplifier (for control circuit),
O P1 ... Differential amplifier (for amplifier circuit), R 1 , R 2 , R 3 ,
R K ...Resistor (for bridge circuit), R H ...Temperature-sensitive resistor, R11 , R12 , R13 , R14 ...Resistor (for amplifier circuit), Tr...Transistor, B...Battery.
Claims (1)
により形成したブリツジ回路と、前記感温抵抗の
流体流量に応じた抵抗値の変化により変化するブ
リツジ回路の非平衡電圧に基づいてブツリジ回路
への供給電流を制御する制御回路とを備え、前記
供給電流に対応する流体流量を測定すると共に、
ブリツジ回路を形成する各抵抗の抵抗温度係数特
性を周辺温度変化に対してブリツジ回路の非平衡
電圧を略一定に保つように設定してなる感温式流
量測定装置において、前記ブリツジ回路の非平衡
電圧を増幅する増幅回路を設け、該増幅回路の出
力電圧に基づいて流体流量を測定するように構成
したことを特徴とする感温式流量測定装置。 A bridge circuit is formed by a temperature-sensitive resistor placed in a fluid passage and a plurality of resistors, and a bridge circuit is connected to the bridge circuit based on an unbalanced voltage of the bridge circuit that changes due to a change in the resistance value of the temperature-sensitive resistor according to the fluid flow rate. a control circuit that controls a supply current of the supply current, and measures a fluid flow rate corresponding to the supply current;
In a temperature-sensitive flow rate measuring device in which the temperature coefficient of resistance of each resistor forming a bridge circuit is set so as to keep the unbalanced voltage of the bridge circuit approximately constant against changes in ambient temperature, the unbalanced voltage of the bridge circuit is 1. A temperature-sensitive flow rate measuring device, comprising: an amplifier circuit for amplifying voltage; and a fluid flow rate measured based on the output voltage of the amplifier circuit.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP4388986U JPH0520979Y2 (en) | 1986-03-27 | 1986-03-27 |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP4388986U JPH0520979Y2 (en) | 1986-03-27 | 1986-03-27 |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS62156832U JPS62156832U (en) | 1987-10-05 |
| JPH0520979Y2 true JPH0520979Y2 (en) | 1993-05-31 |
Family
ID=30861177
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP4388986U Expired - Lifetime JPH0520979Y2 (en) | 1986-03-27 | 1986-03-27 |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH0520979Y2 (en) |
-
1986
- 1986-03-27 JP JP4388986U patent/JPH0520979Y2/ja not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| JPS62156832U (en) | 1987-10-05 |
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