JPS59162431A - Pressure detecting circuit - Google Patents
Pressure detecting circuitInfo
- Publication number
- JPS59162431A JPS59162431A JP3595983A JP3595983A JPS59162431A JP S59162431 A JPS59162431 A JP S59162431A JP 3595983 A JP3595983 A JP 3595983A JP 3595983 A JP3595983 A JP 3595983A JP S59162431 A JPS59162431 A JP S59162431A
- Authority
- JP
- Japan
- Prior art keywords
- output
- comparator
- bridge
- bridge circuit
- pressure
- 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
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01L—MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE
- G01L9/00—Measuring steady of quasi-steady pressure of fluid or fluent solid material by electric or magnetic pressure-sensitive elements; Transmitting or indicating the displacement of mechanical pressure-sensitive elements, used to measure the steady or quasi-steady pressure of a fluid or fluent solid material, by electric or magnetic means
- G01L9/02—Measuring steady of quasi-steady pressure of fluid or fluent solid material by electric or magnetic pressure-sensitive elements; Transmitting or indicating the displacement of mechanical pressure-sensitive elements, used to measure the steady or quasi-steady pressure of a fluid or fluent solid material, by electric or magnetic means by making use of variations in ohmic resistance, e.g. of potentiometers, electric circuits therefor, e.g. bridges, amplifiers or signal conditioning
- G01L9/06—Measuring steady of quasi-steady pressure of fluid or fluent solid material by electric or magnetic pressure-sensitive elements; Transmitting or indicating the displacement of mechanical pressure-sensitive elements, used to measure the steady or quasi-steady pressure of a fluid or fluent solid material, by electric or magnetic means by making use of variations in ohmic resistance, e.g. of potentiometers, electric circuits therefor, e.g. bridges, amplifiers or signal conditioning of piezo-resistive devices
Landscapes
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Measuring Fluid Pressure (AREA)
Abstract
Description
【発明の詳細な説明】
〔発明の利用分野〕
本発明は、圧力検出器に係シ、特に、空燃比（Ａ／Ｆ）
の高度補正に適した大気圧を検出する圧力検出器に関す
る。DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to pressure detectors, and in particular to air-fuel ratio (A/F) sensors.
This invention relates to a pressure detector that detects atmospheric pressure suitable for altitude correction.
自動車は常に理論空燃比で走行できるように制御する。 The vehicle is controlled so that it always runs at the stoichiometric air-fuel ratio.
この理論空燃比（１４，７）で走行するのが最も良いわ
けである。この理論空燃比で走行していても、大気圧の
変化によってその値は変動する。すなわち、７６０ｍＨ
Ｈのとき理論空燃比１４．７であっても、山岳地帯を走
行すると、その気圧の変化によって第１図の如く空燃比
（Ａ／Ｆ）はリッチ側になってくる。これは、燃料量を
吸入空気量Ｑａによって定めており、吸入空気量９人に
対して適正な“燃料が噴射されていても、大気圧の低い
ところでは酸素濃度（０２濃度）が低いため、全体とし
て酸素量に対する燃料量が太くなるのに基づくものであ
る。そこで、この空燃比を補正する必要がある。この空
燃比の補正は、通常吸入空気量ＱＡを補正してやること
によって行われる。この補正を加える時期はめる大気圧
よシ下ったときを基準としている。この気圧を検出する
自動車用圧力検出器としては、圧力に比例した出力を得
るアナログ出力方式と、一定圧力にて出力がオン・オフ
するスイッチング出力方式とが要求される。後者のスイ
ッチング方式のための圧力検出器としては、ベローフラ
ムナ接点といった機械式のものが主流である。このよう
な従来の機械式は、摺動部を有するため、特性の経時変
化が大きく、信頼性に劣り、また外形寸法も大きくなる
という欠点を有している。It is best to run at this stoichiometric air-fuel ratio (14,7). Even when the vehicle is running at this stoichiometric air-fuel ratio, its value fluctuates due to changes in atmospheric pressure. That is, 760mH
Even if the stoichiometric air-fuel ratio is 14.7 at H, when driving in a mountainous area, the air-fuel ratio (A/F) becomes richer as shown in FIG. 1 due to changes in atmospheric pressure. This is because the amount of fuel is determined by the amount of intake air Qa, and even if the appropriate amount of fuel is injected for nine people, the oxygen concentration (02 concentration) is low in areas with low atmospheric pressure. This is based on the fact that the amount of fuel relative to the amount of oxygen increases as a whole. Therefore, it is necessary to correct this air-fuel ratio. Correction of this air-fuel ratio is usually performed by correcting the intake air amount QA. The timing for correction is based on when the atmospheric pressure has dropped below atmospheric pressure.Automotive pressure detectors that detect this atmospheric pressure are available in two types: an analog output method that produces an output proportional to the pressure, and an analog output method that outputs an output proportional to the pressure. A switching output method that turns OFF is required.Pressure detectors for the latter switching method are mainly mechanical types such as bellow flamner contacts.Such conventional mechanical types have a sliding part. Therefore, it has the drawbacks of large changes in characteristics over time, poor reliability, and large external dimensions.
本発明の目的は、スイッチのノ１ンテングを生じさせる
ことなく特性の経時変化が少ない圧力検出回路を提供す
ることにある。SUMMARY OF THE INVENTION An object of the present invention is to provide a pressure detection circuit whose characteristics change less over time without causing switch tension.
本発明は、半導体歪ゲージでブリッジ回路を形成し、そ
のブリッジ中点出力を比較器で比較し、スイッチング出
力を得る敵、比較器の出力をブリッジ駆動端子にフィー
ドバックすることによってヒステリシスを設け、スイッ
チングの出カッ）ンテングを生じさせることなく、特性
の経時変化を少なくしようというものである。The present invention forms a bridge circuit using semiconductor strain gauges, compares the midpoint output of the bridge with a comparator, and provides hysteresis by feeding back the output of the comparator to the bridge drive terminal to obtain the switching output. The aim is to reduce changes in characteristics over time without causing any deterioration.
以■、本発明の実施例について説明する。 Hereinafter, embodiments of the present invention will be described.
第２図には、本発明の一実施例が示されている。FIG. 2 shows an embodiment of the invention.
図において、電＃ＥＲには、サーミスタ１と抵抗２との
直列回路と、抵抗３との並列回路を介して抵抗４と抵抗
５が接続されている。この抵抗４の他端は抵抗６を介し
てアースされており、抵抗５の他端は抵抗７を介してア
ースされている。この抵抗４、抵抗５、抵抗６、抵抗７
ば、いずれもシリコンダイヤスラムに形成したピエゾ抵
抗であシ、ブリッジＧが構成されている。抵抗５と抵抗
７の接続点には、抵抗８を介して比較器１０の（十）入
力端子が接続されている。また、抵抗４と抵抗６の接続
端子には比較器１０の（−）入力端子が接続されている
。この比較器１０は、ブリッジＧの出力電圧ＶＩ Ｖ２
を比較するものであり、ブリッジＧの出力電圧Ｖ、は（
＋）入力端子に、ブリッジＧの出力電圧Ｖ２は（−）入
力端子にそれぞれ入力される。この比較器１０の（十）
入力端子は、抵抗９を介して接地されている。この比較
器１０の出力端子には、出力端子Ｅｏと、抵抗１１を介
してブリッジの入力端にフィードバックされている。In the figure, a resistor 4 and a resistor 5 are connected to the voltage #ER via a series circuit of a thermistor 1 and a resistor 2, and a parallel circuit of a resistor 3. The other end of this resistor 4 is grounded via a resistor 6, and the other end of the resistor 5 is grounded via a resistor 7. This resistance 4, resistance 5, resistance 6, resistance 7
In both cases, the bridge G is composed of a piezoresistor formed on a silicon diamond slum. The (10) input terminal of a comparator 10 is connected to the connection point between the resistors 5 and 7 via a resistor 8. Further, the (-) input terminal of the comparator 10 is connected to the connection terminal between the resistors 4 and 6. This comparator 10 calculates the output voltage VI V2 of the bridge G
The output voltage V of the bridge G is (
The output voltage V2 of the bridge G is input to the +) input terminal, and the output voltage V2 of the bridge G is input to the (-) input terminal, respectively. This comparator 10 (10)
The input terminal is grounded via a resistor 9. The output terminal of the comparator 10 is fed back to the input terminal of the bridge via the output terminal Eo and the resistor 11.
このように構成されるものであるから、シリコンダイヤ
フラムに圧力が印加されると１ピエゾ抵抗４．７は、圧
力に対し抵抗増加、ピエゾ抵抗５゜６は圧力に対し抵抗
減少の抵抗変化を生ずる。したがって、ブリッジＧの中
点電圧ｖ、ｌ Ｖ２は第３図に示す如く、圧力Ｐに比例
し、ｖｌは増加、ｖ２は減少する。Since it is constructed in this way, when pressure is applied to the silicon diaphragm, 1 piezoresistor 4.7 causes a resistance change in response to pressure, and a piezoresistance 5.6 causes a resistance change in which resistance increases and resistance decreases in response to pressure. . Therefore, the midpoint voltage v, l V2 of the bridge G is proportional to the pressure P, as shown in FIG. 3, with vl increasing and v2 decreasing.
したがって、第１図図示比較器１０の（＋）入力端子に
は、ブリッジ中点電圧Ｖｌの抵抗８，９による分割電圧
Ｖ、が、
なる呟になって印加されている。また、比較器１０の（
−）入力端子にはブリッジ中点電圧■２が入力され、（
＋）入力端子に入力される電圧■２と比較される。この
２つの電圧値ＶＯとｖ２のが一致したとき、すなわち、
第３図に示される交点Ｐ１において比較器１０よシ第４
図囚に示す如きＨＩＧＨレベルの信号が出力される。Therefore, the voltage V divided by the resistors 8 and 9 of the bridge midpoint voltage Vl is applied to the (+) input terminal of the comparator 10 shown in FIG. Also, the comparator 10 (
−) The bridge midpoint voltage ■2 is input to the input terminal, and (
+) is compared with the voltage ■2 input to the input terminal. When these two voltage values VO and v2 match, that is,
At the intersection point P1 shown in FIG.
A HIGH level signal as shown in the figure is output.
このＨＩＧＨレベル出力信号によって、吸入空気量の補
正量が変化するため、空燃比（Ａ／Ｆ）が第５図Ａに示
す如く、大気圧ＰＩ （本実施しＵでは６６０ｍＨｇ
）のときに変化（本実施例では１６）する。これによ、
ってエンジン内の燃料がリッチになシすぎることを防止
できる。This HIGH level output signal changes the correction amount of the intake air amount, so that the air-fuel ratio (A/F) changes to atmospheric pressure PI (660mHg in this implementation U), as shown in Figure 5A.
) (16 in this example). With this,
This prevents the fuel in the engine from becoming too rich.
また、比較器１０から第４図囚に示す如きＨＩＧＨレベ
ルの信号が出力されると、抵抗１１を介してブリッジＧ
の入力端にフィードバックされている。このフィードバ
ック電圧によってブリッジＧの入力端の電圧が増加され
るため、ブリッジＧからの出力電圧を入力すΣ比奴器１
０の入力電圧Ｖ、、ｖ２は、第３図図示ｖ、’ 、ｖ、
’の如く変化する。このため、この■ｏ′と■２′との
交点Ｐ２は、フィードバックされる前の電圧特性の交点
Ｐ１よシも大気圧の大きい位置となっている。この帰還
量は抵抗１１によって定まる。これによって、大気圧が
、設定値ＰＩ よシも低く下っても、大気圧Ｐ２までこ
ないと、比較器１０からの出力はＬＯＷにならない。し
たがって、設定気圧Ｐ１．よシ大気圧Ｐ２まで第４図（
Ｂｔに示す如くヒステリシスを有することになる。これ
によって比較器ｌＯから出力される信号のハンチング現
象を防止することができる。Furthermore, when a HIGH level signal as shown in FIG. 4 is output from the comparator 10, the bridge G
is fed back to the input end. Since the voltage at the input terminal of the bridge G is increased by this feedback voltage, the Σ ratio controller 1 which inputs the output voltage from the bridge G
The input voltages V, , v2 of 0 are as shown in FIG.
It changes like '. Therefore, the intersection P2 between ①o' and ②2' is at a position where the atmospheric pressure is higher than the intersection P1 of the voltage characteristics before being fed back. This amount of feedback is determined by the resistor 11. As a result, even if the atmospheric pressure drops to a level lower than the set value PI, the output from the comparator 10 will not become LOW until the atmospheric pressure reaches P2. Therefore, the set atmospheric pressure P1. Figure 4 until atmospheric pressure P2 (
It has hysteresis as shown in Bt. This can prevent the hunting phenomenon of the signal output from the comparator IO.
このように、第４図（ト）のｔのヒステリシス（本実施
例では、７．５ｙａＨｇ ）が働いている間、空燃比（
Ａ／Ｆ ）は第５図Ｂの如くなシ、大気圧が６６７．５
随Ｈｇのところで吸入窒気量Ｑムの補正量が元に戻る。In this way, while the hysteresis of t (in this example, 7.5 yaHg) in FIG.
A/F) is as shown in Figure 5B, and the atmospheric pressure is 667.5.
The correction amount of the intake nitrogen amount Qmu returns to the original value when the amount of Hg is reached.
したがって、本実施列によれば、比較器からの出力にヒ
ステリシスが設けられているから、ハンチングを生ずる
ことがない。Therefore, according to this embodiment, since hysteresis is provided in the output from the comparator, hunting does not occur.
葦た、本実施例によれば、機械式の如き接点を有してい
ないため、接点の摩耗といったことがなく、圧力検出器
の経時変化を生ずることがない。According to this embodiment, since there is no contact such as a mechanical type, there is no wear of the contact and no deterioration of the pressure sensor over time.
以上説明したように、本発明によれば、スイッチのハン
チングを生じさせることなく特性の経時変化を少なくす
ることができる。As described above, according to the present invention, changes in characteristics over time can be reduced without causing switch hunting.
第１図は従来の空燃比の大気圧特性図、第２図は本発明
の実施例を示す回路図、第３図は第２図図示比較器人力
酸圧特性図、第４図（８）は大気圧が下っていったとき
の比較器からの出力波形図、第４図（ト）は大気圧がよ
っていったときの比較器からの出力波形図、第５図は第
２図図示比較器からの出力信号に基づいて変化する空燃
比特性図である。
４．５，６．７・・・ピエゾ抵抗、ｌＯ・・・比較器、
業１９
人□人気圧
第２ 目
華３ 囚
茅４−目Fig. 1 is a conventional air-fuel ratio atmospheric pressure characteristic diagram, Fig. 2 is a circuit diagram showing an embodiment of the present invention, Fig. 3 is a comparator human acid pressure characteristic diagram shown in Fig. 2, and Fig. 4 (8). is a diagram of the output waveform from the comparator when the atmospheric pressure is decreasing, Figure 4 (G) is a diagram of the output waveform from the comparator when the atmospheric pressure is decreasing, and Figure 5 is a comparison shown in Figure 2. FIG. 4 is an air-fuel ratio characteristic diagram that changes based on an output signal from the device. 4.5, 6.7... Piezoresistance, lO... Comparator,
Work 19 Person □Popular Pressure 2 Meka 3 Prisoner 4-Eye
Claims (1)
ッジに一定電出を供給する回路と、前記ブリッジの一方
の出力と他方の出力を２つの抵抗によって分圧した値と
を比較する比較器と、前記比較器の出力端子と前記ブリ
ッジの入力端子との間に挿入接続される抵抗とによって
構成したことを特徴とする圧力検出回路。 ２、特許請求の範囲第１項記載の発明において、上記歪
ゲージは、シリコンダイヤフラムに拡散によシ形成され
るピエゾ抵抗であることを特徴とする圧力検出回路。[Claims] 1. A bridge constituted by a strain gauge, a circuit that supplies a constant voltage to the bridge, and a value obtained by dividing one output and the other output of the bridge by two resistors. A pressure detection circuit comprising: a comparator for comparison; and a resistor inserted and connected between an output terminal of the comparator and an input terminal of the bridge. 2. The pressure detection circuit according to claim 1, wherein the strain gauge is a piezoresistor formed in a silicon diaphragm by diffusion.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP3595983A JPS59162431A (en) | 1983-03-07 | 1983-03-07 | Pressure detecting circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP3595983A JPS59162431A (en) | 1983-03-07 | 1983-03-07 | Pressure detecting circuit |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPS59162431A true JPS59162431A (en) | 1984-09-13 |
Family
ID=12456502
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP3595983A Pending JPS59162431A (en) | 1983-03-07 | 1983-03-07 | Pressure detecting circuit |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS59162431A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6799451B2 (en) * | 2001-03-05 | 2004-10-05 | Delphi Technologies, Inc. | Spark generating apparatus having strain gage cylinder pressure measurement feature |
-
1983
- 1983-03-07 JP JP3595983A patent/JPS59162431A/en active Pending
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6799451B2 (en) * | 2001-03-05 | 2004-10-05 | Delphi Technologies, Inc. | Spark generating apparatus having strain gage cylinder pressure measurement feature |
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