JP3060861B2 - Intake air amount measurement device for internal combustion engine - Google Patents
Intake air amount measurement device for internal combustion engineInfo
- Publication number
- JP3060861B2 JP3060861B2 JP6284778A JP28477894A JP3060861B2 JP 3060861 B2 JP3060861 B2 JP 3060861B2 JP 6284778 A JP6284778 A JP 6284778A JP 28477894 A JP28477894 A JP 28477894A JP 3060861 B2 JP3060861 B2 JP 3060861B2
- Authority
- JP
- Japan
- Prior art keywords
- flow rate
- output signal
- detection unit
- internal combustion
- combustion engine
- Prior art date
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- Combined Controls Of Internal Combustion Engines (AREA)
Description
【０００１】[0001]
【産業上の利用分野】本発明は、内燃機関の吸入空気量
測定装置に係り、特に逆流検知に好適な内燃機関の吸入
空気量測定装置に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a device for measuring the amount of intake air of an internal combustion engine, and more particularly to a device for measuring the amount of intake air of an internal combustion engine suitable for detecting backflow.
【０００２】[0002]
【従来の技術】従来より自動車などの内燃機関の電子制
御燃料噴射装置に設けられ吸入空気量を測定する空気流
量計として、熱線式のものが質量空気量を直接検知でき
ることから主流となってきており、ＳＡＥ paper 800
468，830615 に記載のものが実用化されている。また、
４気筒以下のエンジンの低回転数，重負荷時のように、
吸入空気量の脈動振幅が大きく一部逆流を伴う脈動流の
場合、従来の熱線式空気流量計では精度が低下するた
め、特開昭62−821 号公報に記載のもの、特開昭62−73
124 号公報に記載のもの等が考案されている。2. Description of the Related Art Conventionally, as an air flow meter provided in an electronically controlled fuel injection device of an internal combustion engine such as an automobile for measuring an intake air amount, a hot wire type air flow meter has become mainstream since it can directly detect a mass air amount. Ori, SAE paper 800
468, 830615 have been put to practical use. Also,
As with low engine speeds and heavy loads for engines with four or less cylinders,
In the case of a pulsating flow in which the pulsating amplitude of the intake air amount is large and a partial backflow occurs, the accuracy of the conventional hot-wire air flow meter is reduced. 73
No. 124 has been devised.
【０００３】[0003]
【発明が解決しようとする課題】上記従来技術は、脈動
時に逆流と呼ばれる吸気弁がオーバーラップしていると
きはピストン上昇に伴って排気弁側から正圧で吸気弁側
に戻る空気の吹き返し現象を、従来の熱線式空気流量計
で測定すると、その信号は順流，逆流の流れの方向に関
係なく流速の絶対値に対応した正の信号を出力する。従
って逆流時にあたかも順流のような信号となるので、真
の平均空気流量よりも大きい信号を出力することにな
る。このときの測定誤差は３０〜１００％に達するとい
う問題があった。また、順流，逆流を別々に高速で検出
できる特殊な熱線プローブを用いれば、順流，逆流の空
気流量の差より方向を検出し、方向に応じて空気流量を
出力することで平均空気流量の誤差を少なくすることが
できる。しかし、順流，逆流を別々に高速で検出できる
特殊な熱線プローブを必要とするため、プローブの製造
コストが増大し、信頼性が低下する等の問題があった。According to the above prior art, when the intake valves overlap each other when the intake valves are overlapped, the air returns to the intake valves with a positive pressure from the exhaust valves as the piston rises. Is measured by a conventional hot-wire type air flow meter, the signal outputs a positive signal corresponding to the absolute value of the flow velocity regardless of the direction of the forward or backward flow. Therefore, the signal becomes like a forward flow at the time of the backward flow, so that a signal larger than the true average air flow rate is output. There is a problem that the measurement error at this time reaches 30 to 100%. In addition, if a special hot-wire probe that can separately detect the forward flow and the reverse flow at a high speed is used, the direction is detected from the difference between the air flow of the forward flow and the reverse flow, and the air flow is output according to the direction. Can be reduced. However, since a special hot-wire probe capable of separately detecting the forward flow and the reverse flow at a high speed is required, there have been problems such as an increase in probe manufacturing cost and a decrease in reliability.
【０００４】本発明の目的は、精度良く逆流検知をする
ことができる内燃機関の吸入空気量測定装置を提供する
ことにある。[0004] It is an object of the present invention to provide an apparatus for measuring the amount of intake air of an internal combustion engine, which can accurately detect backflow.
【０００５】[0005]
【課題を解決するための手段】上記目的は、前記検出部
と前記流量演算部との間に前記検出部からの出力信号の
振幅を変えて出力する変調手段を設けることによって達
成される。The above object is achieved by providing modulation means for changing the amplitude of an output signal from the detection section and outputting the output signal between the detection section and the flow rate calculation section.
【０００６】[0006]
【作用】応答遅れを内包した熱線信号をイコライザ回路
で電気的に応答遅れを回復させ、検知した方向信号を基
に、応答遅れを回復した順逆２つの熱線信号出力を切り
替えて出力することにより、真の空気流量そのものに近
い逆流補正した熱線信号を得ることが出来、平均空気流
量の誤差を非常に小さくすることができる。A hot-wire signal containing a response delay is electrically recovered by an equalizer circuit, and based on the detected directional signal, two hot-wire signal outputs in which the response delay is recovered are switched and output. It is possible to obtain a backflow-corrected hot-wire signal close to the true air flow rate itself, and it is possible to greatly reduce the error in the average air flow rate.
【０００７】[0007]
【実施例】以下、本発明の実施例を図１により説明す
る。熱線駆動回路１，２はそれぞれ独立した回路であ
り、電源１０に接続され別々に空気流量に応じた出力を
する。熱線駆動回路１は発熱抵抗体１１，温度補償抵抗
１２，抵抗１３，１４からなるホイーストンブリッジ回
路により、ブリッジ中点の電位差がゼロになるように差
動増幅器１５，トランジスタ１６によって発熱抵抗体１
１に流れる電流を調整するように構成されている。この
構成により空気流速によらず発熱抵抗体１１の抵抗値は
一定に、すなわち温度が一定値になるように制御され
る。このとき、発熱抵抗体１１による空気流速に対応す
る信号は、図中Ａ点の電位である。また熱線駆動回路２
の発熱抵抗体２１も同様であり、発熱抵抗体２１による
空気流速に対応する信号は、図中Ｂ点の電位である。An embodiment of the present invention will be described below with reference to FIG. The hot-wire drive circuits 1 and 2 are independent circuits and are connected to the power supply 10 and output separately according to the air flow rate. The hot-wire drive circuit 1 has a Wheatstone bridge circuit composed of a heating resistor 11, a temperature compensation resistor 12, and resistors 13 and 14, and a differential amplifier 15 and a transistor 16 so that the potential difference at the bridge midpoint becomes zero.
1 is configured to adjust the current flowing through the first element. With this configuration, the resistance of the heating resistor 11 is controlled to be constant, that is, the temperature is kept constant, regardless of the air flow velocity. At this time, the signal corresponding to the air flow velocity by the heating resistor 11 is the potential at point A in the figure. Heat wire drive circuit 2
Similarly, the signal corresponding to the air flow velocity by the heating resistor 21 is the potential at point B in the drawing.
【０００８】ここで発熱抵抗体１１，２１は、例えばセ
ラミックなどの熱伝導性の良い絶縁材料で作られた円筒
状または円柱状のボビンの表面に、発熱体として白金や
タングステンの熱線が巻かれており、被覆材としてガラ
スやセラミックスがコーティングされたものである。発
熱抵抗体１１，２１は板型のガラスやセラミックなどの
基盤上に、発熱体として白金やタングステンの薄膜や厚
膜が形成されたものであっても良い。Here, the heating resistors 11 and 21 are formed by winding a heating wire of platinum or tungsten as a heating element on the surface of a cylindrical or cylindrical bobbin made of an insulating material having good heat conductivity such as ceramic. And coated with glass or ceramic as a coating material. The heating resistors 11 and 21 may be formed by forming a thin film or a thick film of platinum or tungsten as a heating element on a base made of a plate-shaped glass or ceramic.
【０００９】発熱抵抗体１１，２１は自動車等の内燃機
関の吸気通路内に設けられ、例えば吸気上流側には発熱
抵抗体１１が、吸気下流側には発熱抵抗体２１が設けら
れ、近接して平行に配置される。発熱抵抗体１１，２１
の温度は、通常の定温度型熱線流速計と同様に、空気温
度との差が空気流速に関係なく一定値になるように熱線
駆動回路１，２により電気加熱される。まず、吸気上流
側から下流側の順方向に空気が流れるときは、発熱抵抗
体１１は２１に比べて空気流による冷却が大であるの
で、熱線駆動回路１からの供給電流は発熱抵抗体１１の
方が２１より大となる。一方、吸気下流側から上流側の
逆方向に空気が流れるときは、空気流による冷却は前と
逆に発熱抵抗体２１の方が大となり、熱線駆動回路２か
らの供給電流は発熱抵抗体２１の方が１１より大とな
る。従って発熱抵抗体１１，２１への供給電流の大小の
差により、空気流の方向を検知することができる。しか
し、吸気通路内に空気の脈動が生じ、発熱抵抗体１１，
２１の熱応答特性を要因として熱線駆動回路１，２に応
答遅れが生じると空気流の方向の検知が遅れ、平均空気
流量の検出に誤差が生ずる。The heating resistors 11 and 21 are provided in the intake passage of an internal combustion engine such as an automobile. For example, a heating resistor 11 is provided on the upstream side of the intake and a heating resistor 21 is provided on the downstream of the intake. Are arranged in parallel. Heating resistors 11, 21
Is heated by the hot-wire drive circuits 1 and 2 so that the difference from the air temperature becomes a constant value irrespective of the air flow velocity, similarly to a normal constant-temperature hot-wire anemometer. First, when air flows in the forward direction from the intake upstream side to the downstream side, the heating resistor 11 is more cooled by the air flow than the heating resistor 21. Is larger than 21. On the other hand, when air flows in the reverse direction from the downstream side of the intake air to the upstream side, cooling by the air flow is larger in the heating resistor 21, and the supply current from the heating wire driving circuit 2 Is larger than 11. Therefore, the direction of the air flow can be detected based on the difference between the supply currents to the heating resistors 11 and 21. However, air pulsation occurs in the intake passage, and the heating resistor 11,
If a response delay occurs in the hot-wire drive circuits 1 and 2 due to the thermal response characteristic of 21, the detection of the direction of the air flow is delayed, and an error occurs in the detection of the average air flow rate.
【００１０】本実施例では、発熱抵抗体１１，２１のそ
れぞれの空気流量に応じた出力を、イコライザ回路３，
４により電気的に周波数応答性を改善し、電圧比較器５
によりイコライザ回路３，４の出力の大小の差により空
気流の方向を検知するとともに、スイッチ回路６により
イコライザ回路３，４の出力を切り替えて逆流誤差の少
ない流量信号として出力する。スイッチ回路６では逆流
側のイコライザ回路４の出力信号を反転回路６１で反転
することにより、イコライザ回路３，４の出力を切り替
えるものである。この場合、方向信号を外部に出力しな
くても、出力信号のみでエンジンコントロールユニット
とのインターフェイスが可能となる。ここで使用される
スイッチ回路６は、例えばＣＭＯＳプロセスで作られた
アナログスイッチや、バイポーラプロセスで作られたト
ランジスタを用いたアナログスイッチ等であり特に限定
されるものではない。In this embodiment, the outputs according to the respective air flow rates of the heating resistors 11 and 21 are output to the equalizer circuits 3 and 3.
4 to improve the electrical frequency response electrically,
Thus, the direction of the air flow is detected based on the difference between the outputs of the equalizer circuits 3 and 4, and the output of the equalizer circuits 3 and 4 is switched by the switch circuit 6 to be output as a flow signal with a small backflow error. The switch circuit 6 switches the outputs of the equalizer circuits 3 and 4 by inverting the output signal of the equalizer circuit 4 on the reverse flow side by the inverting circuit 61. In this case, it is possible to interface with the engine control unit using only the output signal without outputting the direction signal to the outside. The switch circuit 6 used here is, for example, an analog switch manufactured by a CMOS process or an analog switch using a transistor manufactured by a bipolar process, and is not particularly limited.
【００１１】次に、図２によりイコライザ回路３，４を
用いた場合の詳細の動作を説明する。ここで熱線信号
は、全て空気流量に換算して表示している。一般に空気
流量は、４気筒以下のエンジンの低回転数，重負荷時の
場合、吸入空気量の脈動振幅が大きく図２（１）に示す
ように、逆流と呼ぶ負の空気流量を伴う正弦波に近い波
形となる。これは例えば、エンジン回転数が１０００rp
m の場合は約３３Ｈｚの脈動周波数となる。このような
現象は、エンジンの燃焼室形状，吸排気管形状およびエ
アークリーナ形状などによって異なった形態を示す。Next, the detailed operation when the equalizer circuits 3 and 4 are used will be described with reference to FIG. Here, all the hot-wire signals are converted into air flow rates and displayed. Generally, in the case of an engine having four cylinders or less at a low rotational speed and a heavy load, the pulsation amplitude of the intake air amount is large, and as shown in FIG. Waveform. This means, for example, that the engine speed is 1000 rp
In the case of m, the pulsation frequency is about 33 Hz. Such a phenomenon has a different form depending on the shape of the combustion chamber, the shape of the intake and exhaust pipes, the shape of the air cleaner, and the like of the engine.
【００１２】この逆流を伴った脈動流を、応答性の速い
計測機器に用いられる特殊な熱線プローブを抵抗発熱体
として用いて測定すると、図２（２）に示すように順
流，逆流の方向に関係なく流速の絶対値に対応した正の
信号を出力する。流量に対する応答性がよいため、順流
と逆流の切り替え時には熱線信号はほぼゼロに近くな
る。このような高速応答が可能な特殊な熱線プローブを
２個用いて、順流，逆流の方向を検出して波形を合成す
れば、真の空気流量に最も近い熱線信号を得ることがで
きる。しかし、応答性の速い計測機器に用いられる特殊
な熱線プローブは高価であり、信頼性の点からも自動車
のエンジンなどの振動の大きな機械に定常的に使用する
のは難しい。When the pulsating flow accompanied by the backflow is measured using a special hot-wire probe used in a measuring device having a high response as a resistance heating element, as shown in FIG. Regardless of this, a positive signal corresponding to the absolute value of the flow velocity is output. Since the response to the flow rate is good, the hot-wire signal becomes almost zero when switching between forward flow and reverse flow. If two special hot-wire probes capable of such a high-speed response are used to detect the directions of the forward flow and the reverse flow and synthesize a waveform, a hot-wire signal closest to the true air flow rate can be obtained. However, a special hot-wire probe used for a measurement device with high response is expensive, and it is difficult to constantly use it for a machine with large vibration such as an engine of an automobile from the viewpoint of reliability.
【００１３】そこで、従来より自動車の空気流量の測定
に用いられている、信頼性は高いが応答性は特別速くな
い熱線プローブを２個平行に並べて発熱抵抗体１１，２
１として用いると、図２（３）に示すように順流，逆流
の方向に関係なく流速の絶対値に対応した正の信号を出
力する。この場合、応答遅れが生じることから順流と逆
流の切り替え時において熱線信号はゼロとならない。ま
た吸気上流側に配置された発熱抵抗体１１の出力Ａは、
順流時は大きく逆流時は小さい。逆に吸気下流側に配置
された発熱抵抗体２１の出力Ｂは、逆流時は大きく順流
時は小さい。これら２つの信号を電圧比較器５で比較し
た結果は、図２（４）に示すような順流を示す高電位レ
ベル（Ｈｉ），逆流を示す低電位レベル（Ｌｏｗ）を繰
り返す。スイッチ回路６によって、方向信号を用いて順
逆の切り替えをして逆流補正した熱線信号は、図２
（５）に示すような逆流を伴う合成波形となる。ただ
し、真の空気流量に対して位相がずれ、空気流量がゼロ
付近での波形に飛びが生じるため、平均空気流量を比較
すると、ただ方向信号を用いて合成しただけでは誤差が
生ずることになる。In view of this, two heating wire probes which have been used in the past to measure the air flow rate of an automobile and which have high reliability but not particularly fast response are arranged in parallel and the heating resistors 11 and 12 are arranged.
When used as 1, a positive signal corresponding to the absolute value of the flow velocity is output irrespective of the direction of the forward flow or the backward flow as shown in FIG. In this case, since a response delay occurs, the hot-wire signal does not become zero when switching between the forward flow and the reverse flow. The output A of the heating resistor 11 disposed on the upstream side of the intake air is:
It is large at the time of forward flow and small at the time of reverse flow. Conversely, the output B of the heating resistor 21 arranged on the downstream side of the intake air is large during the reverse flow and small during the forward flow. As a result of comparing these two signals by the voltage comparator 5, a high potential level (Hi) indicating a forward flow and a low potential level (Low) indicating a reverse flow as shown in FIG. 2D are repeated. The hot-wire signal that has been back-flow-corrected by switching forward and reverse using the direction signal by the switch circuit 6 is shown in FIG.
A composite waveform with a backflow as shown in (5) is obtained. However, since the phase shifts with respect to the true air flow rate and the air flow rate jumps near zero, when comparing the average air flow rate, an error will occur if only the synthesis is performed using the direction signal. .
【００１４】本実施例では、図２（３）の応答遅れを内
包した熱線信号を、前記イコライザ回路３，４で電気的
に応答遅れを回復させており、これを図２（６）に示
す。応答遅れを回復した順逆２つの熱線信号出力Ａ２，
Ｂ２は、位相と振幅が真の空気流量に近くなるよう、イ
コライザ回路３，４で調整されている。この新たな信号
Ａ２，Ｂ２を用いて、新たに方向信号を発生させて出力
を切り替え合成することで、図２（７）に示すような真
の空気流量そのものに近い逆流補正した熱線信号を得る
ことが出来、平均空気流量の誤差を非常に小さくするこ
とが出来る。In this embodiment, the response delay of the hot-wire signal including the response delay of FIG. 2 (3) is electrically recovered by the equalizer circuits 3 and 4, as shown in FIG. 2 (6). . Two forward and reverse hot-wire signal outputs A2,
B2 is adjusted by the equalizer circuits 3 and 4 so that the phase and the amplitude are close to the true air flow rate. By using these new signals A2 and B2, a new direction signal is generated and the output is switched and synthesized, a backflow corrected hot-wire signal close to the true air flow rate itself as shown in FIG. 2 (7) is obtained. Therefore, the error of the average air flow rate can be made very small.
【００１５】図３に前記イコライザ回路３，４の周波数
特性の一例を示す。これは、ある一定流速における発熱
抵抗体１１，２１を含む熱線駆動回路１，２の電気的な
周波数応答性を表したものである。熱線駆動回路の応答
性は、カットオフがおおよそ数十Ｈｚと１００Ｈｚ以下
である。例えばエンジン回転数が１０００rpm から２０
００rpm における空気流量の場合は、約３３Ｈｚから約
６６Ｈｚの脈動周波数が発生するため、熱線駆動回路の
カットオフに影響を受け、空気流量の検出値に応答遅れ
が生じる。しかし、例えば図３に示すような位相進み要
素を持たせたイコライザの特性を加えると、合成した応
答性は例えば数百Ｈｚと、熱線駆動回路のみの応答性に
対し一桁速い応答性を実現することが出来る。この場
合、合成した応答性のゲイン特性はフラットなまま周波
数のみが延びる様な特性にすることが望ましい。その結
果、空気流量の検出遅れをなくすことが出来る。FIG. 3 shows an example of the frequency characteristics of the equalizer circuits 3 and 4. This represents the electrical frequency response of the hot-wire drive circuits 1 and 2 including the heating resistors 11 and 21 at a certain constant flow velocity. The response of the hot-wire drive circuit has a cutoff of approximately several tens of Hz and 100 Hz or less. For example, if the engine speed is 1000 rpm to 20
In the case of the air flow rate at 00 rpm, a pulsation frequency of about 33 Hz to about 66 Hz is generated, which is affected by the cut-off of the hot wire drive circuit, and a response delay occurs in the detected value of the air flow rate. However, when the characteristics of an equalizer having a phase lead element as shown in FIG. 3, for example, are added, the combined response is several hundred Hz, for example, which is one order of magnitude faster than the response of the hot wire drive circuit alone. You can do it. In this case, it is desirable that the combined gain characteristic of the response is such that only the frequency is extended while being flat. As a result, detection delay of the air flow rate can be eliminated.
【００１６】前記イコライザ回路３，４を具体的に電気
回路で実現した場合の一実施例を図４に示す。これは差
動増幅器３１を用い、抵抗３３，３４，３６，３８で入
出力ゲインを決定し、抵抗３７，コンデンサ３２，３５
で位相進み要素の周波数特性を決めるものである。FIG. 4 shows an embodiment in which the equalizer circuits 3 and 4 are specifically realized by electric circuits. This uses a differential amplifier 31 to determine the input / output gain with resistors 33, 34, 36, 38, and a resistor 37, capacitors 32, 35
Is used to determine the frequency characteristics of the phase lead element.
【００１７】以上のイコライザ回路を用いた本実施例に
よれば、簡単な回路で特殊な熱線プローブを抵抗発熱体
として用いずとも簡単に応答性を改善することが出来、
平均空気流量の測定精度を比較的容易に向上することが
できる。また、熱線駆動回路の応答性が電気的に改善さ
れるために、電源の起動時の立ち上がり特性を従来より
も速めることができるといった効果もある。According to the present embodiment using the above equalizer circuit, the responsiveness can be easily improved with a simple circuit without using a special hot wire probe as a resistance heating element.
The measurement accuracy of the average air flow rate can be relatively easily improved. In addition, since the responsiveness of the hot-wire drive circuit is electrically improved, there is also an effect that the rising characteristic at the time of starting the power supply can be made faster than before.
【００１８】本発明第２の実施例を図５により説明す
る。本実施例は、図１に示す実施例において、反転回路
をなくし出力信号と方向信号とを用いて順流，逆流の判
定をエンジンコントロールユニット側ですることにより
逆流を考慮した真の流量を計測することができる。本実
施例によれば、出力信号の順流，逆流のダイナミックレ
ンジが大きくとれるため、エンジン制御ユニットでのＡ
／Ｄコンバータによる検出精度が向上する。A second embodiment of the present invention will be described with reference to FIG. In the present embodiment, a true flow rate in consideration of the backflow is measured by eliminating the inversion circuit and using the output signal and the direction signal to determine the forward flow or the backflow on the engine control unit side in the embodiment shown in FIG. be able to. According to the present embodiment, the dynamic range of the forward flow and the reverse flow of the output signal can be widened, so that A
The detection accuracy by the / D converter is improved.
【００１９】本発明の第３の実施例を図６により説明す
る。例えば、エンジンの燃焼室形状，吸排気管形状およ
びエアークリーナ形状により、吸入空気量の脈動振幅が
比較的小さいが逆流を生じてる様な場合においては、応
答遅れによる空気流量振幅の誤差よりも、応答遅れによ
る順流，逆流の方向信号の検出の遅れによる誤差の方が
問題になる場合がある。本実施例では、熱線駆動回路
１，２の出力にイコライザ回路３，４を設けて電圧比較
器５のみに入力し、方向信号の検出専用とするととも
に、空気流量は熱線駆動回路１，２の出力信号Ａ，Ｂを
スイッチ回路６で切り替えて逆流補正した流量出力信号
とする。本実施例の場合、イコライザ回路３，４の出力
を流量出力信号に直接用いていないため、イコライザ回
路３，４の振幅特性を熱線駆動回路１，２に合わせて厳
密に校正せずとも、空気流量の検出に直接影響しない。
また、振幅特性を気にしなければイコライザ回路３，４
は、前記図４の様な差動増幅器等の能動形の部品でな
く、抵抗とコンデンサ等の受動形の部品によっても位相
進み要素を簡単に構成できる。ここで、受動型の部品を
用いたイコライザ回路の実施例を図７により説明する。
これは、抵抗４１，コンデンサ４２からなる低域通過フ
ィルタ（ローパスフィルタ）に、抵抗４３，４４，４
６，コンデンサ４５からなる位相進み回路を持たせて、
交流振幅特性を改善するものである。本実施例では直流
ゲインが低下するが、交流振幅特性のみを変えること
で、特に方向検出用のイコライザ回路として用いること
ができる。A third embodiment of the present invention will be described with reference to FIG. For example, when the pulsation amplitude of the intake air amount is relatively small due to the shape of the combustion chamber, the shape of the intake / exhaust pipe, and the shape of the air cleaner, but a backflow occurs, the response of the air flow amplitude is more than the error of the air flow amplitude due to the response delay. In some cases, the error due to the delay in detecting the forward and backward direction signals due to the delay is more problematic. In the present embodiment, equalizer circuits 3 and 4 are provided at the outputs of the hot-wire driving circuits 1 and 2 and input to only the voltage comparator 5 to detect the direction signal only. The output signals A and B are switched by the switch circuit 6 to be flow output signals corrected for backflow. In the case of the present embodiment, since the outputs of the equalizer circuits 3 and 4 are not directly used for the flow rate output signals, the amplitude characteristics of the equalizer circuits 3 and 4 need not be strictly calibrated in accordance with the hot-wire drive circuits 1 and 2, and the air quality can be reduced. Does not directly affect flow rate detection.
If the amplitude characteristics are not considered, the equalizer circuits 3, 4
The phase lead element can be easily formed by passive components such as resistors and capacitors instead of active components such as the differential amplifier shown in FIG. Here, an embodiment of an equalizer circuit using passive components will be described with reference to FIG.
This is because a low-pass filter (low-pass filter) composed of a resistor 41 and a capacitor 42 is connected to the resistors 43, 44 and 4.
6, with a phase lead circuit consisting of a capacitor 45,
This is to improve the AC amplitude characteristics. In this embodiment, the DC gain is reduced, but by changing only the AC amplitude characteristic, it can be used particularly as an equalizer circuit for direction detection.
【００２０】本実施例によれば、順流，逆流の方向信号
の検出の遅れによる誤差をより低減するため、イコライ
ザ回路３，４の振幅特性を、真の空気流量の振幅よりも
大きくして、逆流時の方向信号の検出感度を高くするこ
とも可能である。本実施例によれば、特に空気流量の脈
動や逆流が小さい場合でも感度よく逆流が検出でき、よ
り正確な空気流量の測定が可能となる。また、イコライ
ザ回路３，４の時定数の設定が容易で、時定数を決める
抵抗やコンデンサの精度を下げることが出来、余分な調
整を必要としない。According to the present embodiment, the amplitude characteristics of the equalizer circuits 3 and 4 are made larger than the amplitude of the true air flow rate in order to further reduce the error due to the delay in detection of the forward and backward flow direction signals. It is also possible to increase the detection sensitivity of the direction signal at the time of backflow. According to this embodiment, the backflow can be detected with high sensitivity even when the pulsation or the backflow of the air flow is small, and the air flow can be measured more accurately. Further, the time constants of the equalizer circuits 3 and 4 can be easily set, the precision of the resistors and capacitors that determine the time constants can be reduced, and no extra adjustment is required.
【００２１】本発明の第４の実施例を図８により説明す
る。例えば、吸入空気量の逆流は少ないが脈動振幅が比
較的大きく、逆流発生による空気流量の誤差よりも脈動
振幅による吸入空気量の平均値の誤差の方が特に問題に
なる場合がある。本実施例では、熱線駆動回路１，２の
出力を電圧比較器５に入力して方向信号を検出し、空気
流量は熱線駆動回路１，２の出力信号Ａ，Ｂをスイッチ
回路６で切り替えて逆流補正した後、第２のイコライザ
回路７を介して脈動振幅を補正して改めて流量出力信号
とする。本実施例の場合、第２のイコライザ回路７を用
いることで脈動振幅の自由な設定が可能なため、平均空
気流量の補正は正負に対してすることが出来る。A fourth embodiment of the present invention will be described with reference to FIG. For example, the backflow of the intake air amount is small, but the pulsation amplitude is relatively large, and the error in the average value of the intake air amount due to the pulsation amplitude may be more problematic than the error in the air flow due to the backflow. In this embodiment, the outputs of the hot-wire drive circuits 1 and 2 are input to the voltage comparator 5 to detect the direction signal, and the air flow rate is changed by switching the output signals A and B of the hot-wire drive circuits 1 and 2 by the switch circuit 6. After the backflow correction, the pulsation amplitude is corrected via the second equalizer circuit 7 to obtain a flow rate output signal again. In the case of the present embodiment, since the pulsation amplitude can be freely set by using the second equalizer circuit 7, the correction of the average air flow rate can be made positive or negative.
【００２２】図９に第２のイコライザ回路７の周波数特
性の一例を示す。これは、ある一定流速における発熱抵
抗体１１，２１を含む熱線駆動回路１，２の電気的な周
波数応答性を表したものである。ここで、熱線駆動回路
の応答性に対し第２のイコライザの周波数特性は、例え
ば図９に示すような位相進み要素を、熱線駆動回路の応
答性がフラットなうちから徐々に加えると、合成した応
答性は例えば数十Ｈｚからゲインが徐々に増加し、かつ
カットオフ周波数が１００Ｈｚ以上となるような応答性
を得ることができる。第２のイコライザ回路７を用いる
と、空気流量に脈動が発生した場合の応答遅れによる脈
動時の振幅の低下を、ゲイン特性を変えることで振幅を
回復させることができ、空気流量を平均値でみた場合の
測定誤差を低減することができる。FIG. 9 shows an example of the frequency characteristic of the second equalizer circuit 7. This represents the electrical frequency response of the hot-wire drive circuits 1 and 2 including the heating resistors 11 and 21 at a certain constant flow velocity. Here, the frequency characteristics of the second equalizer with respect to the responsiveness of the hot-wire drive circuit were synthesized by gradually adding a phase lead element as shown in FIG. 9 while the responsiveness of the hot-wire drive circuit was flat. For example, the response can be obtained such that the gain gradually increases from several tens of Hz and the cutoff frequency becomes 100 Hz or more. When the second equalizer circuit 7 is used, a decrease in amplitude at the time of pulsation due to a response delay when a pulsation occurs in the air flow rate can be recovered by changing the gain characteristic, and the air flow rate can be averaged. In this case, measurement errors can be reduced.
【００２３】第２のイコライザ回路７を具体的に電気回
路で実現した場合の一実施例を図１０に示す。これは、
図４で説明した前記のイコライザ回路３の回路に、入出
力ゲインを変えるためのネットワーク抵抗９１，９２，
９３，９４とコンデンサ９５，９６を加えたものであ
る。抵抗９３の値を調整することで、第２のイコライザ
回路７のゲイン特性を変えることができる。回路そのも
のの基本特性は、差動増幅器７１を用い、抵抗７３，７
４，７６，７８で入出力ゲインを決定し、抵抗７７，コ
ンデンサ７２，７５で位相進み要素の周波数特性を決め
るものである。FIG. 10 shows an embodiment in which the second equalizer circuit 7 is specifically realized by an electric circuit. this is,
The circuit of the equalizer circuit 3 described with reference to FIG.
93 and 94 and capacitors 95 and 96 are added. By adjusting the value of the resistor 93, the gain characteristic of the second equalizer circuit 7 can be changed. The basic characteristics of the circuit itself are as follows.
The input / output gain is determined by 4, 76 and 78, and the frequency characteristics of the phase lead element are determined by the resistor 77 and the capacitors 72 and 75.
【００２４】本実施例では特に第２のイコライザ回路７
を用いれば、少ない回路構成でスロットル開度に対する
空気流量の関係を単調増加性が確保できるように調整で
き、自動車のエンジン制御ユニットとのマッチングが向
上するといった効果がある。本発明の第５の実施例を図
１１により説明する。例えば、吸入空気量の脈動振幅と
逆流がともに大きく、かつ脈動に高調波成分が多く含ま
れる場合、熱線駆動回路１，２の応答遅れによる吸入空
気量の検出誤差が特に大きくなる場合がある。In this embodiment, in particular, the second equalizer circuit 7
Is used, the relationship between the throttle opening and the air flow rate can be adjusted with a small circuit configuration so as to ensure monotonous increase, and the matching with the engine control unit of the vehicle is improved. A fifth embodiment of the present invention will be described with reference to FIG. For example, when the pulsation amplitude and the backflow of the intake air amount are both large and the pulsation contains many harmonic components, the detection error of the intake air amount due to the response delay of the hot wire drive circuits 1 and 2 may be particularly large.
【００２５】本実施例では、熱線駆動回路１，２の出力
をイコライザ回路３，４を設けて電圧比較器５のみに入
力し、方向信号の検出専用とするとともに、空気流量は
熱線駆動回路１，２の出力信号Ａ，Ｂをスイッチ回路６
で切り替えて逆流補正した後、第２のイコライザ回路７
を介して脈動振幅を補正して改めて流量出力信号とす
る。本実施例の場合、逆流発生時の逆流検出の応答遅れ
はイコライザ回路３，４で対応し検出感度を高くでき、
また脈動発生時の応答遅れによる脈動振幅の低下を、第
２のイコライザ回路７を用いることで対応し脈動振幅を
回復し、吸入空気量の検出誤差を総合的に低減すること
が可能となる。In this embodiment, the outputs of the hot-wire drive circuits 1 and 2 are provided only to the voltage comparator 5 by providing equalizer circuits 3 and 4 so as to be used exclusively for detecting the direction signal, and the air flow rate is controlled by the hot-wire drive circuit 1. , 2 from the switch circuit 6
The second equalizer circuit 7 is switched after switching to correct the backflow.
The pulsation amplitude is corrected via, and a flow rate output signal is newly obtained. In the case of this embodiment, the response delay of the backflow detection at the time of occurrence of the backflow can be handled by the equalizer circuits 3 and 4, and the detection sensitivity can be increased.
Further, the use of the second equalizer circuit 7 can cope with a decrease in the pulsation amplitude due to a response delay when the pulsation occurs, thereby recovering the pulsation amplitude and comprehensively reducing the detection error of the intake air amount.
【００２６】本実施例によれば、特に空気流量の脈動や
逆流が大きく乱れた場合でも感度よく逆流が検出でき、
より正確な空気流量の測定が可能となる。逆流と脈動の
感度を別々に設定できるため、エンジンとの組み合わせ
による調整が容易である。According to this embodiment, the backflow can be detected with high sensitivity even if the pulsation of the air flow rate or the backflow is significantly disturbed.
More accurate measurement of the air flow rate becomes possible. Since the sensitivity of the backflow and the pulsation can be set separately, adjustment by the combination with the engine is easy.
【００２７】本発明の第６の実施例を図１２により説明
する。本実施例では、熱線駆動回路１，２におけるブリ
ッジ回路の発熱抵抗体１１，２１を接地側に配置し、温
度補償回路８を設けることで、２つのブリッジ回路を１
個の温度補償抵抗のみで構成することができる。温度補
償回路８は、発振器８９とそのクロック信号で動作する
スイッチ回路８８，８４，８６により、ブリッジ回路の
片側となる温度補償抵抗８１，抵抗８２を、熱線駆動回
路１，２にそれぞれクロックに同期して時分割に切り替
えて動作するものである。この際、スイッチ回路８８で
切り替えた熱線駆動回路１，２内の、トランジスタ１
６，２６のエミッタ側の電位の切り替えによる電圧変動
を少なくするため、差動増幅器８７をバッファとして用
い、接地側の温度補償抵抗８１と直列に接続された抵抗
８２に接続し電流を供給している。温度補償抵抗８１の
出力は、スイッチ回路８４，８６とコンデンサ８３，８
５によって構成されたサンプルホールド回路により、熱
線駆動回路１，２内の差動増幅器１５，２５に連続的に
入力され、それぞれ独立したブリッジ回路として動作す
る。熱線駆動回路１，２の動作を安定にするには、発熱
抵抗体１１，２１と並列に、コンデンサ１７，２７を設
けることが望ましい。A sixth embodiment of the present invention will be described with reference to FIG. In this embodiment, the heating resistors 11 and 21 of the bridge circuits in the hot-wire drive circuits 1 and 2 are arranged on the ground side, and the temperature compensation circuit 8 is provided, so that the two bridge circuits can be connected to one another.
It can be composed of only temperature compensation resistors. The temperature compensating circuit 8 synchronizes the temperature compensating resistors 81 and 82 on one side of the bridge circuit with the clocks of the hot-wire driving circuits 1 and 2 by using an oscillator 89 and switch circuits 88, 84 and 86 operated by the clock signal. It operates by switching to time division. At this time, the transistor 1 in the hot-wire drive circuits 1 and 2 switched by the switch circuit 88
In order to reduce the voltage fluctuation due to the switching of the potentials of the emitters 6 and 26, the differential amplifier 87 is used as a buffer and connected to a resistor 82 connected in series with the temperature compensation resistor 81 on the ground side to supply a current. I have. The output of the temperature compensation resistor 81 is connected to switch circuits 84 and 86 and capacitors 83 and 8.
The sample-and-hold circuit constituted by 5 continuously inputs the differential amplifiers 15 and 25 in the hot-wire drive circuits 1 and 2 and operates as independent bridge circuits. In order to stabilize the operation of the hot wire drive circuits 1 and 2, it is desirable to provide the capacitors 17 and 27 in parallel with the heating resistors 11 and 21.
【００２８】また、熱線駆動回路１，２の出力を電圧比
較器５に入力して方向信号を検出し、空気流量は熱線駆
動回路１，２の出力信号Ａ，Ｂをスイッチ回路６で切り
替えて逆流補正することで流量出力信号を得ることがで
きる。本実施例では、熱線駆動回路の出力にイコライザ
回路を用いない例で説明したが、種々のイコライザ回路
を方向信号の切り替えや、流量出力信号等に組み合わせ
て用いてもかまわない。The outputs of the hot-wire drive circuits 1 and 2 are input to a voltage comparator 5 to detect a direction signal, and the air flow rate is switched by switching output signals A and B of the hot-wire drive circuits 1 and 2 by a switch circuit 6. By performing the backflow correction, a flow rate output signal can be obtained. In this embodiment, an example in which the equalizer circuit is not used for the output of the hot-wire drive circuit has been described. However, various equalizer circuits may be used in combination with the switching of the direction signal, the flow rate output signal, and the like.
【００２９】本実施例によれば、通常吸気通路内に２つ
の発熱抵抗体とともに設けられる比較的高価な温度補償
抵抗を、１個に減らすことができるため原価低減が図れ
る。また、２つのブリッジ回路の温度調整箇所が１ヶ所
ですむため、温度補償抵抗が１個になったことと合わせ
て製造時の組立工数が低減でき、量産時の生産コストが
低減できる。According to the present embodiment, the number of relatively expensive temperature compensating resistors normally provided in the intake passage together with the two heating resistors can be reduced to one, so that the cost can be reduced. Further, since only one temperature adjustment portion is required for the two bridge circuits, the number of assembly steps during manufacturing can be reduced together with the use of only one temperature compensation resistor, and the production cost during mass production can be reduced.
【００３０】本発明の第７の実施例を図１３により説明
する。本実施例では、熱線駆動回路１，２の出力をイコ
ライザ回路３，４を設けて電圧比較器５に入力し、方向
信号の検出専用とするとともに、空気流量は、熱線駆動
回路１，２の出力を第２のイコライザ回路で個々に応答
遅れを回復し、その信号をスイッチ回路６で切り替えて
流量出力信号とする。本実施例の場合、個々のセンサの
周波数応答の違いを個々に調整できるのでより精度が向
上する。A seventh embodiment of the present invention will be described with reference to FIG. In this embodiment, the outputs of the hot-wire drive circuits 1 and 2 are provided to equalizer circuits 3 and 4 and input to a voltage comparator 5 to be used exclusively for detecting a direction signal. The output delay is individually recovered by a second equalizer circuit, and the signal is switched by a switch circuit 6 to be used as a flow rate output signal. In the case of the present embodiment, the difference in the frequency response of each sensor can be individually adjusted, so that the accuracy is further improved.
【００３１】本発明の第８の実施例を図１４により説明
する。本実施例では、イコライザ回路３により熱線駆動
回路１の出力信号の応答遅れを回復させ、その信号を流
量演算部９９に出力する。本実施例の場合、前記検出部
と前記流量演算部との間にイコライザ回路を設けたこと
により空気流量の精度を比較的容易に向上することがで
きる。An eighth embodiment of the present invention will be described with reference to FIG. In the present embodiment, the response delay of the output signal of the hot-wire drive circuit 1 is recovered by the equalizer circuit 3, and the signal is output to the flow rate calculator 99. In the case of the present embodiment, the accuracy of the air flow rate can be relatively easily improved by providing an equalizer circuit between the detection section and the flow rate calculation section.
【００３２】[0032]
【発明の効果】本発明によれば、空気流量が逆流や脈動
流を伴う、通常の熱線プローブを用いた熱線式空気流量
計では測定誤差が増大する場合であっても、平均空気流
量の測定精度を比較的容易に向上することができるとい
った効果がある。また、スロットル開度に対する空気流
量の単調増加性が確保でき、自動車の電子制御燃料噴射
装置に用いるエンジン制御ユニットとのマッチングが向
上するといった効果もある。According to the present invention, the average air flow rate can be measured even when the measurement error increases in a hot-wire type air flow meter using a normal hot-wire probe, in which the air flow rate involves a backflow or a pulsating flow. There is an effect that accuracy can be relatively easily improved. In addition, the monotonous increase of the air flow rate with respect to the throttle opening can be ensured, and the matching with the engine control unit used in the electronically controlled fuel injection device of the vehicle is improved.
【図１】本発明の実施例によるイコライザ回路を用いた
熱線駆動回路図。FIG. 1 is a diagram of a hot-wire drive circuit using an equalizer circuit according to an embodiment of the present invention.
【図２】吸入空気流が逆流を伴った脈動流の場合の動作
波形図。FIG. 2 is an operation waveform diagram in a case where the intake air flow is a pulsating flow accompanied by a reverse flow.
【図３】熱線駆動回路図及びイコライザ回路の周波数特
性図。FIG. 3 is a diagram of a hot-wire drive circuit and a frequency characteristic diagram of an equalizer circuit.
【図４】イコライザ回路の実施例。FIG. 4 is an embodiment of an equalizer circuit.
【図５】本発明の実施例によるイコライザ回路を用いた
熱線駆動回路図。FIG. 5 is a diagram of a hot-wire drive circuit using an equalizer circuit according to an embodiment of the present invention.
【図６】本発明の実施例によるイコライザ回路を用いた
熱線駆動回路図。FIG. 6 is a hot-wire drive circuit diagram using an equalizer circuit according to an embodiment of the present invention.
【図７】イコライザ回路の実施例。FIG. 7 is an embodiment of an equalizer circuit.
【図８】本発明の実施例による第２のイコライザ回路を
用いた熱線駆動回路図。FIG. 8 is a hot-wire drive circuit diagram using a second equalizer circuit according to an embodiment of the present invention.
【図９】熱線駆動回路図及び第２のイコライザ回路の周
波数特性図。FIG. 9 is a diagram of a hot-wire drive circuit and a frequency characteristic diagram of a second equalizer circuit.
【図１０】第２のイコライザ回路の実施例。FIG. 10 shows an embodiment of a second equalizer circuit.
【図１１】本発明の実施例による第１と第２のイコライ
ザ回路を用いた熱線駆動回路図。FIG. 11 is a diagram of a hot-wire drive circuit using first and second equalizer circuits according to an embodiment of the present invention.
【図１２】本発明の実施例による温度補償抵抗を１個に
した熱線駆動回路図。FIG. 12 is a diagram of a hot-wire drive circuit with one temperature compensation resistor according to an embodiment of the present invention.
【図１３】本発明の実施例による温度補償抵抗を１個に
した熱線駆動回路図。FIG. 13 is a hot-wire drive circuit diagram with one temperature compensation resistor according to an embodiment of the present invention.
【図１４】本発明の実施例によるイコライザ回路を用い
た熱線駆動回路図。FIG. 14 is a hot-wire drive circuit diagram using an equalizer circuit according to an embodiment of the present invention.
１，２…熱線駆動回路、３，４…イコライザ回路、５…
電圧比較器、６，８４，８６，８８…スイッチ回路、７
…第２のイコライザ回路、８…温度補償回路、１０…電
源、１１，２１…発熱抵抗体、１２，２２，８１…温度
補償抵抗、１３，１４，２３，２４，３３，３４，３
６，３７，３８，７３，７４，７６，７７，７８，９
１，９２，９３，９４…抵抗、１５，２５，８７…差動
増幅器、１６，２６…トランジスタ、１７，２７，３
２，３５，７２，７５，８３，８５，９５，９６…コン
デンサ、８９…発振器、９９…流量演算部。1, 2,... Hot-wire drive circuit, 3, 4,.
Voltage comparator, 6, 84, 86, 88: switch circuit, 7
... second equalizer circuit, 8 ... temperature compensation circuit, 10 ... power supply, 11, 21 ... heating resistor, 12, 22, 81 ... temperature compensation resistor, 13, 14, 23, 24, 33, 34, 3
6,37,38,73,74,76,77,78,9
1, 92, 93, 94: resistor, 15, 25, 87: differential amplifier, 16, 26: transistor, 17, 27, 3
2, 35, 72, 75, 83, 85, 95, 96: condenser, 89: oscillator, 99: flow rate calculation unit.
───────────────────────────────────────────────────── フロントページの続き (72)発明者 内山 薫 茨城県ひたちなか市大字高場2520番地 株式会社 日立製作所 自動車機器事業 部内 (56)参考文献 特開 昭56−108909（ＪＰ，Ａ) 特開 昭63−302320（ＪＰ，Ａ) 特開 昭62−812（ＪＰ，Ａ) 特開 昭62−73124（ＪＰ，Ａ) (58)調査した分野(Int.Cl.7，ＤＢ名) G01F 1/68 F02D 35/00 F02D 45/00 366 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Kaoru Uchiyama 2520 Oaza Takaba, Hitachinaka-shi, Ibaraki Automobile Equipment Division, Hitachi, Ltd. (56) References JP-A-56-108909 (JP, A) JP-A Sho 63-302320 (JP, A) JP-A-62-812 (JP, A) JP-A-62-73124 (JP, A) (58) Fields investigated (Int. Cl. 7 , DB name) G01F 1/68 F02D 35/00 F02D 45/00 366
Claims (12)
の出力信号に基づき空気流量を算出する流量演算部とを
備えた内燃機関の吸入空気量測定装置において、前記検
出部と前記流量演算部との間に、前記検出部からの信号
の振幅を変えて出力する変調手段を設けたことを特徴と
する内燃機関の吸入空気量測定装置。1. An intake air amount measuring device for an internal combustion engine, comprising: a detecting section including a heating resistor; and a flow rate calculating section for calculating an air flow rate based on an output signal from the detecting section. A device for measuring the amount of intake air of an internal combustion engine, further comprising a modulating means for changing and outputting the amplitude of the signal from the detecting unit between the calculating unit and the calculating unit.
イザ回路であることを特徴とする内燃機関の吸入空気量
測定装置。2. An apparatus according to claim 1, wherein said modulation means is an equalizer circuit.
差動増幅器を用い、抵抗器（３３，３４，３６，３８）
で入出力ゲインを決定し、抵抗器（３７）とコンデンサ
で位相進み要素を設定し、前記入出力ゲインの周波数特
性を決定することを特徴とする内燃機関の吸入空気量測
定装置。3. The equalizer circuit according to claim 2, wherein said equalizer circuit uses a differential amplifier, and includes a resistor (33, 34, 36, 38).
An input / output gain is determined by using a resistor (37) and a capacitor to set a phase lead element, and a frequency characteristic of the input / output gain is determined.
は、抵抗器(４１)とコンデンサ(４１)によって構成され
た低域通過フィルタと前記低域通過フィルタの出力を入
力とする抵抗器（４３，４４，４６）とコンデンサ（４
５）で構成された位相進み回路により、前記イコライザ
回路の入出力ゲインと周波数特性が決定されることを特
徴とする内燃機関の吸入空気量測定装置。4. The equalizer circuit according to claim 2, wherein the equalizer circuit includes a low-pass filter including a resistor (41) and a capacitor (41), and a resistor (43, 44, 46) and capacitor (4
The input / output gain and frequency characteristics of the equalizer circuit are determined by the phase lead circuit configured in 5).
回路であることを特徴とする内燃機関の吸入空気量測定
装置。5. An apparatus according to claim 1, wherein said detecting section is a bridge circuit.
つの検出部と前記検出部からの出力信号に基づき空気流
量を算出する流量演算部とを備えた内燃機関の吸入空気
量測定装置において、前記検出部と前記流量演算部との
間に、前記検出部からの出力信号の周波数成分の振幅を
変えて出力する変調手段を個々に設けたことを特徴とす
る内燃機関の吸入空気量測定装置。6. A bridge circuit comprising a heat generating resistor.
An intake air amount measurement device for an internal combustion engine, comprising: a detection unit; and a flow rate calculation unit that calculates an air flow rate based on an output signal from the detection unit, wherein the detection is performed between the detection unit and the flow rate calculation unit. An intake air amount measuring device for an internal combustion engine, wherein modulation means for changing and outputting the amplitude of the frequency component of the output signal from the section are provided individually.
つの検出部と前記検出部からの出力信号に基づき空気流
量を算出する流量演算部とを備えた内燃機関の吸入空気
量測定装置において、前記検出部と前記流量演算部との
間に、前記検出部からの出力信号の周波数成分の位相を
変えて出力する変調手段を個々に設けたことを特徴とす
る内燃機関の吸入空気量測定装置。7. A bridge circuit comprising a heat-generating resistor.
An intake air amount measurement device for an internal combustion engine, comprising: a detection unit; and a flow rate calculation unit that calculates an air flow rate based on an output signal from the detection unit, wherein the detection is performed between the detection unit and the flow rate calculation unit. An intake air amount measuring device for an internal combustion engine, wherein modulation means for changing and outputting the phase of a frequency component of an output signal from a section are provided individually.
つの検出部と前記検出部からの出力信号に基づき空気流
量を算出する流量演算部とを備えた内燃機関の吸入空気
量測定装置において、前記検出部と前記流量演算部との
間に前記検出部からの出力信号を変調するイコライザ回
路を個々に設け、前記イコライザ回路により変調された
個々の出力信号から空気の流れ方向を検出する手段を設
け、検出した前記空気の流れ方向に基づき、前記イコラ
イザ回路の出力を切り替えて前記流量演算部に出力する
手段を設けたことを特徴とする内燃機関の吸入空気量測
定装置。8. A bridge circuit comprising a heating resistor, wherein the bridge circuit includes a heating resistor.
An intake air amount measurement device for an internal combustion engine, comprising: a detection unit; and a flow rate calculation unit that calculates an air flow rate based on an output signal from the detection unit, wherein the detection unit is disposed between the detection unit and the flow rate calculation unit. An equalizer circuit for modulating an output signal from the controller, and a means for detecting a flow direction of air from each output signal modulated by the equalizer circuit, wherein the equalizer circuit is provided based on the detected flow direction of the air. Means for switching the output of the internal combustion engine and outputting the output to the flow rate calculation unit.
つの検出部と前記検出部からの出力信号に基づき空気流
量を算出する流量演算部とを備えた内燃機関の吸入空気
量測定装置において、前記検出部と前記流量演算部との
間に前記検出部からの出力信号を変調するイコライザ回
路を個々に設け、前記イコライザ回路により変調された
個々の出力信号から空気の流れ方向を検出する手段を設
け、検出した前記空気の流れ方向に基づき、前記ブリッ
ジ回路の出力を切り替えて前記流量演算部に出力する手
段を設けたことを特徴とする内燃機関の吸入空気量測定
装置。9. A bridge circuit comprising a heating resistor.
An intake air amount measurement device for an internal combustion engine, comprising: a detection unit; and a flow rate calculation unit that calculates an air flow rate based on an output signal from the detection unit, wherein the detection unit is disposed between the detection unit and the flow rate calculation unit. An equalizer circuit that modulates an output signal from the individual is provided, and means for detecting a flow direction of air from each output signal modulated by the equalizer circuit is provided.Based on the detected flow direction of the air, the bridge circuit is provided. Means for switching the output of the internal combustion engine and outputting the output to the flow rate calculation unit.
２つの検出部と前記検出部からの出力信号に基づき空気
流量を算出する流量演算部とを備えた内燃機関の吸入空
気量測定装置において、前記検出部と前記流量演算部と
の間に前記検出部からの出力信号を変調する第１のイコ
ライザ回路と第２のイコライザ回路を個々に設け、前記
第１のイコライザ回路により変調された個々の出力信号
から空気の流れ方向を検出する手段を設け、検出した前
記空気の流れ方向に基づき、前記第２のイコライザ回路
の出力を切り替えて前記流量演算部に出力する手段を設
けたことを特徴とする内燃機関の吸入空気量測定装置。10. An intake air amount measuring apparatus for an internal combustion engine, comprising: two detection units each including a bridge circuit including a heating resistor; and a flow rate calculation unit that calculates an air flow rate based on an output signal from the detection unit. A first equalizer circuit and a second equalizer circuit for modulating an output signal from the detection unit are separately provided between the detection unit and the flow rate calculation unit, and the individual equalizer circuits modulated by the first equalizer circuit are provided. A means for detecting a flow direction of air from an output signal is provided, and a means for switching an output of the second equalizer circuit and outputting the output to the flow rate calculation unit based on the detected flow direction of air is provided. For measuring the amount of intake air of an internal combustion engine.
２つの検出部と前記検出部からの出力信号に基づき空気
流量を算出する流量演算部とを備えた内燃機関の吸入空
気量測定装置において、前記検出部と前記流量演算部と
の間に、前記ブリッジ回路の出力信号から空気の流れ方
向を検出する検出手段と、前記検出手段によって検出さ
れた空気の流れ方向に基づき、前記ブリッジ回路の出力
を切り替える切替手段と、前記切替手段によって切り替
えられた前記ブリッジ回路の出力信号を変調するイコラ
イザ回路とを設けたことを特徴とする内燃機関の吸入空
気量測定装置。11. An intake air amount measuring device for an internal combustion engine, comprising: two detection units each including a bridge circuit including a heating resistor; and a flow rate calculation unit that calculates an air flow rate based on an output signal from the detection unit. Detecting means for detecting a flow direction of air from an output signal of the bridge circuit between the detection section and the flow rate calculation section; and an output of the bridge circuit based on the flow direction of air detected by the detection means. And an equalizer circuit for modulating an output signal of the bridge circuit switched by the switching means.
２つの検出部と前記検出部からの出力信号に基づき空気
流量を算出する流量演算部とを備えた内燃機関の吸入空
気量測定装置において、前記検出部と前記流量演算部と
の間に、前記検出部からの出力信号を変調する各々のイ
コライザ回路と前記イコライザ回路により変調された個
々の出力信号から空気の流れ方向を検出する検出手段
と、検出された空気の流れ方向に基づき、前記ブリッジ
回路の出力を切り替える切替手段と、前記切替手段によ
って切り替えられた前記ブリッジ回路の出力信号を変調
するイコライザ回路とを有することを特徴とする内燃機
関の吸入空気量測定装置。12. An intake air amount measuring device for an internal combustion engine, comprising: two detection units each including a bridge circuit including a heating resistor; and a flow rate calculation unit that calculates an air flow rate based on an output signal from the detection unit. Between the detection unit and the flow rate calculation unit, each equalizer circuit that modulates an output signal from the detection unit, and a detection unit that detects a flow direction of air from individual output signals modulated by the equalizer circuit. An internal combustion engine comprising: switching means for switching the output of the bridge circuit based on the detected flow direction of air; and an equalizer circuit for modulating an output signal of the bridge circuit switched by the switching means. Intake air volume measurement device.
Priority Applications (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP6284778A JP3060861B2 (en) | 1994-11-18 | 1994-11-18 | Intake air amount measurement device for internal combustion engine |
| US08/560,981 US5681989A (en) | 1994-11-18 | 1995-11-20 | Intake air amount measuring apparatus for internal combustion engines |
| DE19543236A DE19543236C2 (en) | 1994-11-18 | 1995-11-20 | Intake air quantity measuring device for internal combustion engines |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP6284778A JP3060861B2 (en) | 1994-11-18 | 1994-11-18 | Intake air amount measurement device for internal combustion engine |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH08145754A JPH08145754A (en) | 1996-06-07 |
| JP3060861B2 true JP3060861B2 (en) | 2000-07-10 |
Family
ID=17682898
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP6284778A Expired - Fee Related JP3060861B2 (en) | 1994-11-18 | 1994-11-18 | Intake air amount measurement device for internal combustion engine |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP3060861B2 (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2017090322A (en) * | 2015-11-13 | 2017-05-25 | 日立オートモティブシステムズ株式会社 | Airflow measurement device |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP7168340B2 (en) * | 2018-04-11 | 2022-11-09 | 日立Astemo株式会社 | thermal flow meter |
-
1994
- 1994-11-18 JP JP6284778A patent/JP3060861B2/en not_active Expired - Fee Related
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2017090322A (en) * | 2015-11-13 | 2017-05-25 | 日立オートモティブシステムズ株式会社 | Airflow measurement device |
Also Published As
| Publication number | Publication date |
|---|---|
| JPH08145754A (en) | 1996-06-07 |
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