JP2000002568A - Air flow rate measuring apparatus - Google Patents
Air flow rate measuring apparatusInfo
- Publication number
- JP2000002568A JP2000002568A JP10169818A JP16981898A JP2000002568A JP 2000002568 A JP2000002568 A JP 2000002568A JP 10169818 A JP10169818 A JP 10169818A JP 16981898 A JP16981898 A JP 16981898A JP 2000002568 A JP2000002568 A JP 2000002568A
- Authority
- JP
- Japan
- Prior art keywords
- resistor
- temperature
- air
- heating resistor
- air flow
- 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
- Measuring Volume Flow (AREA)
Abstract
Description
【０００１】[0001]
【発明の属する技術分野】本発明は、発熱抵抗体式の流
量計測装置に係り、特に内燃機関の吸入空気流量計測用
として好適な空気流量測定装置に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heating resistor type flow measuring device, and more particularly to an air flow measuring device suitable for measuring an intake air flow of an internal combustion engine.
【０００２】[0002]
【従来の技術】発熱抵抗体式の流量測定装置では、一般
に計測すべき流体の通路に流量検出素子となる発熱抵抗
体と、温度検出素子となる感温抵抗体の２個の抵抗体を
設置する必要がある。そこで、従来の発熱抵抗体式流量
測定装置では、図１２に示すように、空気通路Ａ内の計
測すべき空気の流通方向Ｆに対して発熱抵抗体１を前方
に、感温抵抗体２は後方に配置し、且つ、このとき、こ
れら発熱抵抗体１と感温抵抗体２は、空気流通方向Ｆの
中心の流線ＬC の両側にある異なった流線ＬA 、ＬB 上
に位置するようにして、空気通路６の中に設置してい
た。この図１２で、３は発熱抵抗体１の支持ピン、４は
感温抵抗体２の支持ピン、５は吸入空気通路部材を表わ
す。なお、Ｄは各抵抗体に形成された塵埃などの堆積物
を表わすが、詳しい説明は後述する。2. Description of the Related Art In a heating resistor type flow measuring device, two resistors, a heating resistor serving as a flow detecting element and a temperature sensing resistor serving as a temperature detecting element, are generally provided in a passage of a fluid to be measured. There is a need. Therefore, in the conventional heating resistor type flow rate measuring device, as shown in FIG. 12, the heating resistor 1 is located forward and the temperature sensing resistor 2 is located backward with respect to the flow direction F of the air to be measured in the air passage A. placed, and, at this time, these heat-generating resistor 1 and the temperature sensitive resistor 2, streamlines differently on each side of the flow line L C of the center of the air flow direction F L a, located on L B Thus, it was installed in the air passage 6. In FIG. 12, reference numeral 3 denotes a support pin of the heating resistor 1, 4 denotes a support pin of the temperature-sensitive resistor 2, and 5 denotes an intake air passage member. D represents a deposit such as dust formed on each resistor, and will be described in detail later.
【０００３】このような発熱抵抗体式流量測定装置の従
来技術としては、例えば特開平１−４３８８４号公報の
開示を挙げることができる。なお、この公報に開示の装
置では、内燃機関の吸入空気が流入する主通路から吸入
空気の一部が流入する副通路を分岐させ、この副通路内
に発熱抵抗体と感温抵抗体を設けるようにした、いわゆ
るバイパス方式になっている。[0003] As a prior art of such a heating resistor type flow rate measuring device, for example, the disclosure of Japanese Patent Application Laid-Open No. 1-43884 can be mentioned. In the device disclosed in this publication, a sub-passage into which a part of the intake air flows from the main passage into which the intake air of the internal combustion engine flows flows, and a heating resistor and a temperature-sensitive resistor are provided in the sub-passage. This is the so-called bypass method.
【０００４】[0004]
【発明が解決しようとする課題】上記従来技術は、発熱
抵抗体に生じる塵埃の堆積についての配慮がされておら
ず、使用中での計測精度低下の問題があった。一般に、
大気中から空気を取り込んだ場合、その中には粉塵や埃
の存在がほとんど不可避であり、特に路上を走行する自
動車では、内燃機関の吸入空気への塵埃の混入が著し
い。In the above prior art, no consideration is given to the accumulation of dust generated on the heating resistor, and there has been a problem of a decrease in measurement accuracy during use. In general,
When air is taken in from the atmosphere, the presence of dust and dust is almost inevitable. Especially in automobiles running on roads, dust is significantly mixed into the intake air of the internal combustion engine.
【０００５】発熱抵抗体式の流量測定装置では、その検
出素子となる発熱抵抗体が、計測すべき空気流中に直接
さらされているため、それに塵埃が付着し易く、上記し
た図１２に示すように、発熱抵抗体１と感温抵抗体２の
表面に、時間の経過とともに徐々に塵埃などの堆積物Ｄ
が形成されてしまい、この結果、流量測定特性が変化
し、計測精度が低下してしまうのである。In the heating resistor type flow rate measuring device, since the heating resistor serving as the detecting element is directly exposed to the airflow to be measured, dust easily adheres to the heating resistor, as shown in FIG. In addition, a deposit D such as dust is gradually formed on the surfaces of the heating resistor 1 and the temperature-sensitive resistor 2 with the passage of time.
Is formed, and as a result, the flow rate measurement characteristics change, and the measurement accuracy decreases.
【０００６】特に、従来技術では、発熱抵抗体１から空
気流Ａへの熱の伝達が、空気流Ａが発熱抵抗体１に最初
に接触する正面方向の極く僅かな部分からの熱伝達に大
きく依存しているため、この部分、すなわち空気の流通
方向Ｆに向かっている正面部分に、図１２に示すよう
に、堆積物Ｄが生成されると、たとえそれが僅かであっ
ても発熱抵抗体１から空気流Ａへの熱伝達量が大きく変
化してしまい、空気流量測定誤差の著しい増大をもたら
してしまう。In particular, in the prior art, the transfer of heat from the heating resistor 1 to the airflow A is limited to the heat transfer from a very small portion in the front direction where the airflow A first contacts the heating resistor 1. As shown in FIG. 12, when the deposit D is generated in this portion, that is, in the front portion facing the air flow direction F, even if the deposit is small, the heat generation resistance The amount of heat transferred from the body 1 to the air flow A changes greatly, resulting in a significant increase in air flow measurement errors.
【０００７】なお、この塵埃などの堆積物Ｄは、図示の
ように感温抵抗体２にも生じるが、この感温抵抗体２の
機能は空気の温度検知にあるので、堆積物Ｄが形成され
ても影響はほとんど無く、問題になることもほとんどな
い。[0007] The deposits D such as dust are also generated on the temperature-sensitive resistor 2 as shown in the figure. However, since the function of the temperature-sensitive resistor 2 is to detect the temperature of air, the deposit D is formed. This has little effect and is unlikely to cause a problem.
【０００８】ところで、この塵埃の堆積の問題について
対処した従来技術としては、発熱抵抗体と感温抵抗体の
表面にコーティングを施し、塵埃を滑り易くする方法が
あった。しかし、この従来技術では、それほど塵埃の堆
積を抑えることができず、不十分であった。[0008] As a conventional technique for dealing with the problem of the accumulation of dust, there has been a method of coating the surfaces of the heating resistor and the temperature-sensitive resistor to make the dust slippery. However, this conventional technique cannot sufficiently suppress the accumulation of dust, and is insufficient.
【０００９】一方、この問題に対処した従来技術として
は、発熱抵抗体の前方に障害物を配置する方法があっ
た。発熱抵抗体の前方に障害物を設置すると、空気流は
最初に障害物に接触し、このとき、障害物を基点として
流れの方向に対して垂直な方向に流線が分岐し、分岐し
た空気流はそのまま下流に流れるようになる。On the other hand, as a prior art which addresses this problem, there is a method of disposing an obstacle in front of a heating resistor. When an obstacle is installed in front of the heating resistor, the air flow first contacts the obstacle, and at this time, the streamline branches off in a direction perpendicular to the flow direction with the obstacle as the base point, and the branched air The stream will flow downstream as it is.
【００１０】そこで、この空気流が分岐した部分に発熱
抵抗体を配置してやれば、発熱抵抗体の前面に対する直
接的な空気流の接触は無くなり、小さいカルマン渦が接
触するだけとなる。しかして、この場合には、発熱抵抗
体の前面に対して斜め方向から空気が接触する状態にな
るので、塵埃は発熱抵抗体の表面で滑ってしまい、堆積
が抑えられるのである。Therefore, if a heating resistor is arranged at a portion where the airflow branches, direct contact of the airflow with the front surface of the heating resistor is lost, and only a small Karman vortex comes into contact. In this case, air comes into contact with the front surface of the heating resistor from an oblique direction, so that dust slides on the surface of the heating resistor and deposition is suppressed.
【００１１】しかしながら、この従来技術では、発熱抵
抗体を保持するピンと感温抵抗体を保持するピンの他
に、更に障害物を保持するピンも必要になり、部品点数
の増加による設置スペースの増大を招き、装置のコンパ
クト化が阻害され、エンジンルーム内での取り付け自由
度が低下してまう。そして、このことは、特に、上記し
た副通路方式に適用した場合に著しく、副通路が狭いた
め、ほとんど適用できなくなってしまう。However, in this prior art, a pin for holding an obstacle is required in addition to a pin for holding a heating resistor and a pin for holding a temperature-sensitive resistor, and the installation space is increased due to an increase in the number of parts. This hinders downsizing of the device and reduces the degree of freedom in installation in the engine room. This is particularly remarkable when applied to the above-described sub-passage system. The sub-passage is so narrow that it is hardly applicable.
【００１２】また、溶接などによるピンに対する組付け
に際しても、２個の抵抗体の他に、更に障害物の取付も
必要になるので、各部の寸法関係を維持した状態での組
立作業が極めて困難になり、大きなコスト上昇が避けら
れない。Also, when assembling to the pin by welding or the like, it is necessary to mount an obstacle in addition to the two resistors, so that it is extremely difficult to perform an assembling operation while maintaining the dimensional relationship of each part. And a large increase in cost is inevitable.
【００１３】本発明の目的は、発熱抵抗体と感温抵抗体
以外に余分な機構を要せず、長期間にわたって塵埃の堆
積が抑えられ、常に高精度の流量検出が得られるように
した発熱抵抗体式の空気流量測定装置を提供することに
ある。An object of the present invention is to provide a heat generating device which does not require an extra mechanism other than a heat generating resistor and a temperature sensing resistor, suppresses accumulation of dust for a long period of time, and always obtains a highly accurate flow rate detection. An object of the present invention is to provide a resistor type air flow measuring device.
【００１４】[0014]
【課題を解決するための手段】上記目的は、流量を計測
すべき空気が通流される通路の中に、該通路内での空気
の流通方向の前後に並んで配置した発熱抵抗体と感温抵
抗体を備えた発熱抵抗式の空気流量測定装置において、
前記発熱抵抗体と前記感温抵抗体が、前記感温抵抗体が
前記通路内の空気の流れの前方に位置し、前記発熱抵抗
体が前記通路内の空気の流れの後方に位置するようにし
て、前記空気の流れの同一流線上に揃えて平行に配置さ
れ、前記発熱抵抗体に対する塵埃の堆積を防止するため
の障害物としての働きが、前記感温抵抗体により得られ
るようにして達成される。SUMMARY OF THE INVENTION It is an object of the present invention to provide a heating element having a heating resistor arranged in a passage through which air whose flow rate is to be measured is arranged in front and rear of the passage of air in the passage. In a heating resistance type air flow measuring device equipped with a resistor,
The heating resistor and the temperature-sensitive resistor are arranged such that the temperature-sensitive resistor is located in front of the airflow in the passage, and the heating resistor is located behind the airflow in the passage. The temperature-sensitive resistor is arranged so as to be arranged in parallel on the same streamline of the air flow and function as an obstacle for preventing the accumulation of dust on the heating resistor. Is done.
【００１５】[0015]
【発明の実施の形態】以下、本発明による空気流量測定
装置について、図示の実施形態により詳細に説明する。
図３と図４は、本発明をバイパス式の空気流量測定装置
に適用した場合の一実施形態を模式的に示した図で、６
は流量測定装置のボディ、７は主空気通路、８は副空気
通路部材、９は副空気通路(バイパス通路)、１０は駆動
回路(流量検出回路)であり、その他、発熱抵抗体１、感
温抵抗体２、ピン３、４などは、図１２の従来技術と同
じである。DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an air flow measuring device according to the present invention will be described in detail with reference to the illustrated embodiments.
FIGS. 3 and 4 are diagrams schematically showing an embodiment in which the present invention is applied to a bypass type air flow measuring device.
, A main air passage; 8, a sub air passage member; 9, a sub air passage (bypass passage); 10, a drive circuit (flow detection circuit); The thermal resistor 2, the pins 3, 4 and the like are the same as in the prior art of FIG.
【００１６】ピン３、４はテンレスなどの耐蝕性の材料
で作られ、発熱抵抗体１と感温抵抗体２をを副空気通路
９内に保持し、且つ、駆動回路１０に対する電気的接続
路を確保する働きをするもので、このため、これらのピ
ン３、４は、それぞれ発熱抵抗体１と感温抵抗体２から
駆動回路１０にまで伸ばされている。The pins 3 and 4 are made of a corrosion-resistant material such as stainless steel. The pins 3 and 4 hold the heating resistor 1 and the temperature-sensitive resistor 2 in the auxiliary air passage 9 and provide an electrical connection to the drive circuit 10. Therefore, these pins 3 and 4 are extended from the heating resistor 1 and the temperature-sensitive resistor 2 to the driving circuit 10, respectively.
【００１７】ボディ６は、例えば内燃機関の吸入空気通
路の一部を構成するもので、金属、又は合成樹脂で作ら
れ、全吸入空気流量が流入する主空気通路７と、吸入空
気流量の一部が流入する副空気通路９を形成し、且つ、
駆動回路１０を保持しする働きをする。The body 6 constitutes, for example, a part of an intake air passage of an internal combustion engine, and is made of metal or synthetic resin. Forming a sub air passage 9 into which the section flows, and
It functions to hold the drive circuit 10.
【００１８】副空気通路部材８は、主として合成樹脂で
作られ、主空気通路７から一部の空気をバイパスして流
し込み、再び主空気通路７に戻る副空気通路９を形成す
る働きをするもので、この副空気通路９内に発熱抵抗体
１と感温抵抗体２が設置されている。The auxiliary air passage member 8 is mainly made of a synthetic resin, and has a function of forming a sub air passage 9 which bypasses a part of air from the main air passage 7 and flows back to the main air passage 7 again. The heating resistor 1 and the temperature-sensitive resistor 2 are provided in the auxiliary air passage 9.
【００１９】次に、この発熱抵抗体１と感温抵抗体２を
用いた空気流量測定装置の動作原理について簡単に説明
する。発熱抵抗体１は、空気温度を計測する感温抵抗体
１と常に一定の温度差に保たれるように、駆動回路１０
内のフィードバック回路により常時加熱され、定温度制
御されている。この発熱抵抗体１は空気流の中に設置さ
れ、その空気流に接している表面部分が放熱面、つまり
熱伝達面となり、このときの熱伝達量は、空気流の速度
の関数になる。Next, the operation principle of the air flow measuring device using the heating resistor 1 and the temperature-sensitive resistor 2 will be briefly described. The driving circuit 10 is provided so that the heating resistor 1 is always kept at a constant temperature difference from the temperature-sensitive resistor 1 for measuring the air temperature.
It is constantly heated by a feedback circuit inside, and is controlled at a constant temperature. The heating resistor 1 is installed in an air flow, and a surface portion in contact with the air flow serves as a heat radiation surface, that is, a heat transfer surface, and the amount of heat transfer at this time is a function of the speed of the air flow.
【００２０】そこで、この熱伝達により空気流に奪われ
る熱量を、発熱抵抗体１の加熱に必要な電力として捉
え、電気的信号に変換することにより空気流量を計測す
るのである。このとき、感温抵抗体２は、空気の温度を
電気抵抗の変化として捉え、温度補償を行ない、質量流
量による空気流量が正確に計測できるようにする。Therefore, the amount of heat taken by the air flow due to the heat transfer is regarded as electric power necessary for heating the heating resistor 1 and converted into an electric signal to measure the air flow rate. At this time, the temperature-sensitive resistor 2 captures the temperature of the air as a change in electric resistance, performs temperature compensation, and accurately measures the air flow rate based on the mass flow rate.
【００２１】図５は発熱抵抗体１と感温抵抗体２の一実
施形態例で、まず、外径が０．３〜０．９ｍｍφで、長
さが２〜３ｍｍ程度の、アルミナ等の安価な汎用無機材
からなる小さな円筒状部材１１を用い、この円筒状部材
１１の両端から孔の中に直径０．２ｍｍφ程度の金属線
を挿入し、接合材１３により溶着固定してリード線１２
とする。FIG. 5 shows an embodiment of the heating resistor 1 and the temperature-sensitive resistor 2. First, an inexpensive material such as alumina having an outer diameter of 0.3 to 0.9 mm and a length of about 2 to 3 mm is used. Using a small cylindrical member 11 made of a general-purpose inorganic material, a metal wire having a diameter of about 0.2 mmφ is inserted into a hole from both ends of the cylindrical member 11, and is welded and fixed with a bonding material 13 to form a lead wire 12.
And
【００２２】このリード線１２としては、白金線、白金
合金線、或いは非貴金属材料の線材の表面に貴金属材料
をクラッドした線が使用されることが多く、接合材１３
としては、ガラス系の無機物が使用される場合が多い。As the lead wire 12, a platinum wire, a platinum alloy wire, or a wire in which a noble metal material is clad on the surface of a non-noble metal material is often used.
In many cases, a glass-based inorganic material is used.
【００２３】次に、白金などの細い線を用意し、その端
部を一方のリード線１２に溶接し、これを基点にして円
筒状部材１１の表面にヘリカル(蔓巻き)状に巻回し、所
定の抵抗値になったところで他方のリード線１２に溶接
し、所定の抵抗値をもった抵抗体部分１４とする。最後
に、この抵抗体部分１４を保護するため、ガラスなどの
コーティング１５を施して発熱抵抗体１又は感温抵抗体
２とするのである。Next, a thin wire made of platinum or the like is prepared, and its end is welded to one of the lead wires 12, and is wound helically (wound) around the surface of the cylindrical member 11 with this as a base point. When the resistance value reaches a predetermined value, it is welded to the other lead wire 12 to form a resistor portion 14 having a predetermined resistance value. Finally, in order to protect the resistor portion 14, a coating 15 such as glass is applied to form the heating resistor 1 or the temperature-sensitive resistor 2.
【００２４】図６は発熱抵抗体１と感温抵抗体２の他の
一実施形態例で、図５の実施形態における白金細線を巻
回した抵抗部分１４に代えて、円筒状部材１１の端面と
円周面に、リード線１２の一部も含めて白金などの薄膜
を形成し、この薄膜の表面をヘリカル状にレーザートリ
ミングすることにより、所定の抵抗値を有する抵抗体部
分１６としたものであり、他の構成は図５の実施形態と
同じである。FIG. 6 shows another embodiment of the heat-generating resistor 1 and the temperature-sensitive resistor 2, wherein an end face of a cylindrical member 11 is used instead of the resistor portion 14 wound with a platinum thin wire in the embodiment of FIG. A thin film of platinum or the like including a part of the lead wire 12 is formed on the circumferential surface, and the surface of the thin film is laser-trimmed into a helical shape to form a resistor portion 16 having a predetermined resistance value. The other configuration is the same as the embodiment of FIG.
【００２５】図７は、空気流量測定装置の具体的な使用
態様の一例を模式的に示した図で、自動車用内燃機関の
空気流量測定装置に適用した場合を示してあり、内燃機
関のエアクリーナ１７とエアクリーナダクト１８の間に
空気流量測定装置のボディ６を配置したものである。エ
アクリーナ２０の空気取り入れ口から流入した空気Ａは
エアクリーナエレメント１７Ｅにより清浄化され、空気
流量測定装置のボディ６に流入する。そして、空気Ａの
一部の流れが副空気通路８に流れ込み、発熱抵抗体１及
び感温抵抗体２を通過することにより空気流量が計測さ
れ、流量が計測された空気がエアクリーナダクト２１を
介して内燃機関のシリンダに吸入されることになる。FIG. 7 is a diagram schematically showing an example of a specific use mode of the air flow measuring device, and shows a case where the air flow measuring device is applied to an air flow measuring device of an internal combustion engine for a vehicle. The body 6 of the air flow measuring device is arranged between the air cleaner 17 and the air cleaner duct 18. The air A flowing from the air intake of the air cleaner 20 is cleaned by the air cleaner element 17E and flows into the body 6 of the air flow measuring device. Then, a part of the flow of the air A flows into the auxiliary air passage 8 and passes through the heating resistor 1 and the temperature-sensitive resistor 2, whereby the air flow rate is measured, and the air having the measured flow rate passes through the air cleaner duct 21. As a result, it is sucked into the cylinder of the internal combustion engine.
【００２６】この結果、駆動回路１０から内燃機関の制
御装置に空気流量を計測した信号が供給され、この流量
計測信号と、回転数センサなどの他のセンサからの信号
に基いて、制御装置のマイクロコンピュータが燃料供給
量を演算し、内燃機関を制御する。そしてこのとき、こ
の発熱抵抗体式の空気流量測定装置によれば、直接、質
量流量が計測できるという特長があり、この結果、多く
の内燃機関制御システムに採用されている。As a result, a signal obtained by measuring the air flow rate is supplied from the drive circuit 10 to the control device of the internal combustion engine. The microcomputer calculates the fuel supply amount and controls the internal combustion engine. At this time, the heating resistor type air flow measuring device has a feature that the mass flow can be directly measured, and as a result, it is adopted in many internal combustion engine control systems.
【００２７】ここで、図３と図４の実施形態に戻り、本
発明が特徴とする構成について説明する。これらの図
３、図４の実施形態では、図１で詳細に示してあるよう
に、発熱抵抗体１と感温抵抗体２が、何れも流量を計測
すべき空気Ａの流通方向Ｆに沿った同一の流線ＬC 上に
揃って設置してあり、しかも、このとき、感温抵抗体２
が発熱抵抗体１の前に設置してある。この図１は、発熱
抵抗体１と感温抵抗体２の設置状態を詳細に示すため
に、図３の副空気通路８の一部を拡大して示したもの
で、この図を、従来技術を表わす図１２と対比してみれ
ば、両者の違いを明瞭に知ることができる。Here, returning to the embodiment of FIGS. 3 and 4, a configuration characteristic of the present invention will be described. In the embodiments shown in FIGS. 3 and 4, as shown in detail in FIG. 1, both the heating resistor 1 and the temperature-sensitive resistor 2 move along the flow direction F of the air A whose flow rate is to be measured. were Yes installed aligned on the same flow line L C, moreover, at this time, the temperature sensitive resistor 2
Is provided in front of the heating resistor 1. FIG. 1 is an enlarged view of a part of the sub air passage 8 of FIG. 3 in order to show the installation state of the heating resistor 1 and the temperature sensitive resistor 2 in detail. The difference between the two can be clearly understood by comparing with FIG.
【００２８】次に、図２は、感温抵抗体２として、その
直径が、発熱抵抗体１の直径よりも小さいものを用いた
場合の本発明の一実施形態を示したもので、この実施形
態でも、発熱抵抗体１と感温抵抗体２が、何れも流量を
計測すべき空気Ａの流通方向Ｆに沿った同一の流線ＬC
上に揃って設置してあり、しかも、このとき、感温抵抗
体２が発熱抵抗体１の前に設置してあることが特徴とな
っている。Next, FIG. 2 shows an embodiment of the present invention in which a temperature-sensitive resistor 2 whose diameter is smaller than the diameter of the heat-generating resistor 1 is used. Also in the embodiment, both the heating resistor 1 and the temperature-sensitive resistor 2 have the same flow line L C along the flow direction F of the air A whose flow rate is to be measured.
It is characterized in that the temperature-sensitive resistor 2 is installed in front of the heating resistor 1 at this time.
【００２９】以下、本発明の構成による特有の動作につ
いて、説明する。この実施形態のような発熱抵抗体式の
空気流量測定装置では、その発熱抵抗体１と感温抵抗体
２は、必ず流量を計測すべき空気の中にさらされる。一
方、特に内燃機関の吸入空気には、たとえ図７に示すよ
うに、エアクリーナ１７を介したとしても、或る程度以
下の微細な塵埃の除去は事実上不可能で、微細な塵埃の
混入が常時避けられず、このため、発熱抵抗体１と感温
抵抗体２の表面には、内燃機関の運転時間の経過と共に
徐々に塵埃が堆積されてしまう。Hereinafter, a specific operation according to the configuration of the present invention will be described. In the heating resistor type air flow measuring device as in this embodiment, the heating resistor 1 and the temperature sensitive resistor 2 are always exposed to the air whose flow rate is to be measured. On the other hand, in particular, as shown in FIG. 7, it is practically impossible to remove fine dust having a certain degree or less from the intake air of the internal combustion engine, even through the air cleaner 17, and the fine dust is not mixed. As a result, dust is gradually deposited on the surfaces of the heating resistor 1 and the temperature-sensitive resistor 2 as the operation time of the internal combustion engine elapses.
【００３０】ここで、このときの塵埃が堆積する仕組み
(メカニズム)について説明する。発熱抵抗体１(感温抵
抗体２も同じ)に空気流が接触(衝突と表現した方が的確
かもしれない)した際、塵埃は、発熱抵抗体１の表面に
含まれた長さ方向の直線部分で、流線ＬC に沿って最前
部にある直線部分から、すなわち、図１で点Ｐを通って
流線ＬC と垂直になって発熱抵抗体１の表面に含まれた
直線部分から堆積し始める。Here, the mechanism of accumulation of dust at this time
(Mechanism) will be described. When the airflow comes into contact with the heating resistor 1 (the same is true for the temperature-sensitive resistor 2) (it may not be more appropriate to describe the collision as dust), dust is generated in the length direction included on the surface of the heating resistor 1 From the straight line portion at the forefront along the stream line L C , that is, a straight line included in the surface of the heating resistor 1 perpendicular to the stream line L C through the point P in FIG. Begin to deposit from the part.
【００３１】これは、塵埃を含んだ空気流が発熱抵抗体
１又は感温抵抗体２に接触した際、塵埃が充分に微細で
あると、これらの表面と塵埃との間にファンデルワーズ
力が作用し、空気中の塵埃を引き寄せる作用が発生する
ためと考えられている。This is because when the dust-containing airflow contacts the heating resistor 1 or the temperature-sensitive resistor 2, if the dust is sufficiently fine, a van der Waals force is generated between the surface and the dust. It is believed that the effect of the above is to act to attract dust in the air.
【００３２】このように、塵埃が発熱抵抗体１又は感温
抵抗体２の表面に引き寄せられたとき、発熱抵抗体１又
は感温抵抗体２の上記直線上の部分は、微視的には平面
となり、この平面部から塵埃が堆積し始める。対して、
発熱抵抗体１又は感温抵抗体２の側面から後方に向かう
部分では、表面に引き寄せられた塵埃は、この部分の表
面が円周状に収縮してゆく状態になっているため、表面
で滑ってしまって、発熱抵抗体１又は感温抵抗体２には
付着し難く、このため、図１２の従来技術で示したよう
に、空気流に逆らって前方に向かう形で堆積物Ｄが生成
されてしまうのである。As described above, when the dust is attracted to the surface of the heating resistor 1 or the temperature-sensitive resistor 2, the linear portion of the heating resistor 1 or the temperature-sensitive resistor 2 is microscopically observed. It becomes a flat surface, and dust starts to accumulate from this flat surface. for,
In a portion of the heat-generating resistor 1 or the temperature-sensitive resistor 2 extending rearward from the side surface, the dust attracted to the surface slides on the surface because the surface of this portion is contracted circumferentially. As a result, the deposits D hardly adhere to the heating resistor 1 or the temperature-sensitive resistor 2, and therefore, as shown in the prior art of FIG. It will be.
【００３３】本発明では、図１と図２の実施形態に示し
たように、発熱抵抗体１の前方に感温抵抗体２を配置す
ることにより、上記した障害物を用いた従来技術の利点
を生かしつつコンパクトな構造にでき、バイパス式の空
気流量測定装置にも容易に適用し得るようにしたもので
ある。According to the present invention, as shown in the embodiment of FIGS. 1 and 2, the temperature-sensitive resistor 2 is disposed in front of the heating resistor 1 to obtain the advantage of the prior art using the above-mentioned obstacle. This makes it possible to make a compact structure while taking advantage of the fact that it can be easily applied to a bypass type air flow measuring device.
【００３４】図１及び図２に戻り、まず、図１の実施形
態では、副空気通路８内で、同一の空気流線ＬC 上に前
後して配置される発熱抵抗体１と感温抵抗体２が、同一
寸法の抵抗素子で構成されている。この場合、前方の感
温抵抗体２と後方の発熱抵抗体１の間隔が近すぎると、
感温抵抗体２により分岐し、膨らんだ空気流がそのまま
で発熱抵抗体１に達してしまい、そのまま通過してしま
うようになってしまうため、発熱抵抗体１に接触する空
気流が不安定となる。[0034] Returning to Figures 1 and 2, firstly, in the embodiment of FIG. 1, in the bypass passage 8, a heating resistor 1 and the temperature sensitive resistor are arranged one behind on the same air flow line L C The body 2 is composed of resistance elements having the same dimensions. In this case, if the distance between the front temperature sensing resistor 2 and the rear heating resistor 1 is too small,
Since the air flow branched by the temperature-sensitive resistor 2 and swelling reaches the heating resistor 1 as it is and passes through the heating resistor 1 as it is, the air flow in contact with the heating resistor 1 becomes unstable. Become.
【００３５】反対に、離れすぎると、障害物による空気
流の分岐効果が得られ無くなって、塵埃の堆積を抑える
ことができなくなってしまう。発熱抵抗体１の直径をｄ
１、感温抵抗体２の直径をｄ２、間隔をＬとすると、 Ｌ≧（ｄ１＋ｄ２)／２ と定義するのが好適である。On the other hand, if the distance is too large, the effect of branching off the air flow due to the obstacles cannot be obtained, and the accumulation of dust cannot be suppressed. Let the diameter of the heating resistor 1 be d
1. If the diameter of the temperature-sensitive resistor 2 is d2 and the interval is L, it is preferable to define L ≧ (d1 + d2) / 2.
【００３６】次に、図２の実施形態では、感温抵抗体２
の直径が、発熱抵抗体１の直径よりも小さくしてある。
これは、障害物の機能を兼ねた感温抵抗体２の寸法を小
さくすることにより、障害物による塵埃の堆積を抑制す
る機能を損なわずに、発熱抵抗体１が空気流に接触する
面積、すなわち空気流に対する有効伝熱面積を増大し、
伝熱促進が促されるようにするためであり、従って、こ
の実施形態は、より一層の精度向上を図るのに有効であ
る。Next, in the embodiment shown in FIG.
Is smaller than the diameter of the heating resistor 1.
This is because, by reducing the size of the temperature-sensitive resistor 2 which also functions as an obstacle, the area where the heating resistor 1 comes into contact with the airflow without impairing the function of suppressing the accumulation of dust due to the obstacle, That is, the effective heat transfer area for the air flow is increased,
This is to promote heat transfer, and therefore, this embodiment is effective for further improving accuracy.
【００３７】ここで、発熱抵抗体１の直径をｄ１、感温
抵抗体２の直径をｄ２、直径比をαとすると、 α＝ｄ１／ｄ２＞１ と定義することが好適である。Here, if the diameter of the heating resistor 1 is d1, the diameter of the temperature sensing resistor 2 is d2, and the diameter ratio is α, it is preferable to define α = d1 / d2> 1.
【００３８】また、副空気通路８内の吸入空気の同一流
線ＬC 上に配置される感温抵抗体２と発熱抵抗体１にお
いて、感温抵抗体２の中心線を規準とした際、発熱抵抗
体１の流線ＬC からの位置のばらつきは±１ｍｍ以内に
することが好ましい。When the temperature-sensitive resistor 2 and the heating resistor 1 disposed on the same flow line L C of the intake air in the sub air passage 8 are set with respect to the center line of the temperature-sensitive resistor 2, It is preferable that the variation of the position of the heating resistor 1 from the streamline L C be within ± 1 mm.
【００３９】次に、本発明により得られた塵埃の堆積抑
制結果について、従来技術と比較しながら説明する。い
ま、従来技術による流量測定装置に、ある割合で塵埃を
含んだ空気を所定時間通流させたとき、発熱抵抗体１と
感温抵抗体２に生じる塵埃の堆積物Ｄを観察し、スケッ
チした結果が図１２に示すようになったとき、図２に示
した本発明の一実施形態による流量測定装置に、同じく
空気を通流させたときには、発熱抵抗体１と感温抵抗体
２に生じる塵埃の堆積物Ｄは、図８に示すようになっ
た。Next, the result of suppressing the accumulation of dust obtained by the present invention will be described in comparison with the prior art. Now, when air containing dust at a certain rate is passed through a conventional flow rate measuring device for a predetermined time, a deposit D of dust generated on the heating resistor 1 and the temperature-sensitive resistor 2 was observed and sketched. When the result is as shown in FIG. 12, when the air flows through the flow rate measuring apparatus according to the embodiment of the present invention shown in FIG. 2, the heating resistor 1 and the temperature-sensitive resistor 2 are generated. The dust deposit D was as shown in FIG.
【００４０】図１２に示した従来技術では、発熱抵抗体
１と感温抵抗体２の双方に塵埃の堆積物Ｄが形成されし
ている。しかして、本発明の実施形態では、図８に示す
ように、感温抵抗体２には塵埃の堆積物Ｄが形成されて
いるが、発熱抵抗体１には塵埃が堆積することはなく、
明らかに塵埃の堆積が抑制できることが判る。既に説明
したように、感温抵抗体２は吸気温度補償用であり、塵
埃が堆積しても空気温度の測定にはほとんど影響を受け
ないので、空気流量測定精度を悪化させる虞れはない。In the prior art shown in FIG. 12, a deposit D of dust is formed on both the heating resistor 1 and the temperature-sensitive resistor 2. Thus, in the embodiment of the present invention, as shown in FIG. 8, the dust deposit D is formed on the temperature-sensitive resistor 2, but the dust is not deposited on the heating resistor 1.
It is clear that the accumulation of dust can be suppressed. As described above, the temperature-sensitive resistor 2 is used for compensating the intake air temperature. Even if dust accumulates, the measurement of the air temperature is hardly affected.
【００４１】次に、図９は、図１２に示した従来技術に
よる空気流量測定装置の特性(耐塵埃性)測定結果と、図
２に示した本発明の実施形態による空気流量測定装置の
特性測定結果を、それぞれ特性Ｘ(一点鎖線)と特性Ｙ
(実線)で示したもので、各特性Ｘ、Ｙは、通流させた空
気量に対する誤差の大きさを表わしている。Next, FIG. 9 shows the measurement results of the characteristics (dust resistance) of the air flow measuring device according to the prior art shown in FIG. 12 and the characteristics of the air flow measuring device according to the embodiment of the present invention shown in FIG. The measurement results are shown as a characteristic X (dot-dash line) and a characteristic Y
The characteristics X and Y are shown by (solid lines), and represent the magnitude of the error with respect to the flowed air amount.
【００４２】この図９から明らかなように、従来技術で
は、通流させた空気量の増加につれ堆積物Ｄの形成が進
むので、誤差は大きく変化してしまう。例えば、図示の
場合では、特性Ｙに示すように、空気通過量の増加に伴
ってプラスの誤差からマイナスの誤差に著しく大きく変
化してしまうので、常に誤差を最小値に抑えることはで
きない。As is clear from FIG. 9, in the prior art, the formation of the deposit D progresses with an increase in the amount of flowing air, so that the error greatly changes. For example, in the case shown in the figure, as shown by the characteristic Y, the error significantly changes from a positive error to a negative error with an increase in the amount of air passing, so that the error cannot always be suppressed to the minimum value.
【００４３】これに対して、本発明の実施形態では、空
気の通過量が増加していっても、誤差にはほとんど変化
が現れず、特性Ｘに示すように、ほぼ一定値に保たれ、
従って、本発明の実施形態によれば、塵埃による発熱抵
抗体１への堆積物Ｄの形成が確実に抑えられていること
が判り、この結果、常に最小の誤差に抑えることができ
る。On the other hand, in the embodiment of the present invention, even if the amount of air passing increases, the error hardly changes, and as shown by the characteristic X, the error is kept almost constant.
Therefore, according to the embodiment of the present invention, it can be seen that the formation of the deposit D on the heating resistor 1 due to dust is reliably suppressed, and as a result, the error can always be suppressed to the minimum.
【００４４】次に、本発明によれば、更に別の観点から
も、空気流量測定精度の向上が得られるものであり、以
下、この点について説明する。通常、空気流は、そのレ
イノルズ数が４０００以下では層流となり、以上では乱
流となる。そして、層流と乱流とが入り混じった状態は
遷移域と呼ぶ。そして、この遷移域では、空気の流れが
安定しにくいため、空気流がばらついてノイズが増大す
るので、空気流量測定精度が悪化する。Next, according to the present invention, the air flow measurement accuracy can be improved from still another viewpoint. This will be described below. Normally, the air flow becomes laminar when the Reynolds number is 4000 or less, and becomes turbulent when the Reynolds number is 4000 or more. A state in which laminar flow and turbulent flow are mixed is called a transition region. In this transition region, since the air flow is difficult to stabilize, the air flow varies and noise increases, so that the air flow measurement accuracy deteriorates.
【００４５】本発明では、図１と図２の実施形態に示し
たように、同一流線ＬC 上の前方に感温抵抗体２を配置
し、発熱抵抗体１を後方に揃えて配置することにより、
感温抵抗体２が発熱抵抗体１に対する障害物として働く
ようにしてあり、この結果、以下に説明するように、発
熱抵抗体１の近傍で空気流が遷移域になるのが抑えら
れ、低空気流量から高空気流量に至るまでの領域で、常
に強制的に乱流状態とすることができ、従って、空気流
量測定精度の悪化が抑えられるばかりか、その向上が得
られる。According to the present invention, as shown in the embodiment of FIGS. 1 and 2, the temperature-sensitive resistor 2 is disposed in front of the same streamline L C , and the heating resistor 1 is arranged rearward. By doing
The temperature-sensitive resistor 2 acts as an obstacle to the heating resistor 1. As a result, as described below, the transition of the airflow near the heating resistor 1 to the transition region is suppressed, In the region from the air flow rate to the high air flow rate, a turbulent state can always be forcibly generated. Therefore, not only the deterioration of the air flow measurement accuracy is suppressed, but also the improvement is obtained.
【００４６】発熱抵抗体１の前方に配置された感温抵抗
体２は、空気流に対する障害物として働き、ここで空気
流が層流状態になっていたときでも、感温抵抗体２との
接触により乱流にされ、そのまま後方にある発熱抵抗体
１に接触する。一方、空気流が感温抵抗体２に接触した
とき、乱流になっていた場合には、そのまま後方に流れ
てゆくので、やはり乱流のまま発熱抵抗体１に接触す
る。The temperature-sensitive resistor 2 disposed in front of the heat-generating resistor 1 acts as an obstacle to the airflow, and even when the airflow is in a laminar flow state, the temperature-sensitive resistor 2 is in contact with the temperature-sensitive resistor 2. The turbulent flow is generated by the contact, and the turbulent flow comes into contact with the heating resistor 1 at the rear as it is. On the other hand, when the airflow comes into contact with the temperature-sensitive resistor 2 and becomes turbulent, it flows backward as it is, so that the airflow again contacts the heating resistor 1 in a turbulent flow.
【００４７】従って、この実施形態によれば、空気流が
遷移域になる虞れがなく、発熱抵抗体１には、常に乱流
状態にある空気流だけが接触することになり、この結
果、空気流量測定精度が安定し、精度向上が得られるの
である。Therefore, according to this embodiment, there is no possibility that the air flow will be in the transition region, and only the turbulent air flow will be in contact with the heating resistor 1 at all times. The air flow measurement accuracy is stable, and the accuracy can be improved.
【００４８】次に、本発明により得られる空気流量測定
精度向上について、更に具体的に説明する。まず、図１
１は、図１２に示した従来技術における発熱抵抗体１と
感温抵抗体２の近傍における空気の流れを示したもの
で、この場合、感温抵抗体２と発熱抵抗体１の後方に
は、いずれも障害物が無い。Next, the improvement of the air flow measurement accuracy obtained by the present invention will be described more specifically. First, FIG.
Numeral 1 indicates the flow of air in the vicinity of the heating resistor 1 and the temperature-sensitive resistor 2 in the prior art shown in FIG. There are no obstacles.
【００４９】この結果、空気流がそれぞれ感温抵抗体２
と発熱抵抗体１に接触して、それぞれ両側に分流した
後、直ちに合流されるようになるが、この場合には、図
示のように、双子渦と呼称される２対の渦２０が発生し
易く、この双子渦２０は、一旦生成されると、空気流が
層流の場合には、発熱抵抗体１の後方まで対流しつづけ
るため、発熱抵抗体１の後方部分では、空気に対する熱
伝達はほとんど行われなくなってしまい、発熱抵抗体１
の前方の部分２１だけで空気に対する熱伝達が行なわれ
るだけになってしまう。As a result, each of the airflows is
After contacting with the heating resistor 1 and diverging to both sides, respectively, they are immediately merged. In this case, two pairs of vortices 20 called twin vortices are generated as shown in the figure. Once the twin vortex 20 is generated, once the air flow is laminar, it continues to convect to the rear of the heating resistor 1, so that heat transfer to the air at the rear portion of the heating resistor 1 does not occur. It is hardly performed, and the heating resistor 1
Only the heat transfer to the air is carried out only in the front part 21.
【００５０】従って、従来技術では、この双子渦２０の
発生により、発熱抵抗体１の空気流に対する熱伝達部分
が極く一部の部分２１に限定されてしまうことになり、
検出感度が充分に得られなくなって、精度保持が困難に
なってしまうことになる。Therefore, in the prior art, due to the generation of the twin vortex 20, the heat transfer portion of the heating resistor 1 to the air flow is limited to a very small portion 21.
The detection sensitivity cannot be sufficiently obtained, and it becomes difficult to maintain the accuracy.
【００５１】次に、図１０は、図２に示した本発明の一
実施形態の場合で、このときは、空気流は、まず障害物
を兼ねた感温抵抗体２に接触する。この場合、感温抵抗
体２の後方の同一流線ＬC に発熱抵抗体１があるため、
感温抵抗体２で分流された空気流は直ちに合流せず、分
流されたまま流れるので、双子渦が発生することなく、
代りに小さなカルマン渦２２が発生し、この状態で発熱
抵抗体１に接触し、カルマン渦２２を伴ったままで後方
に流れ込むようになる。Next, FIG. 10 shows the case of the embodiment of the present invention shown in FIG. 2. In this case, the air flow first contacts the temperature-sensitive resistor 2 which also serves as an obstacle. In this case, since the heating resistor 1 is located at the same streamline L C behind the temperature-sensitive resistor 2,
The air flows split by the temperature-sensitive resistor 2 do not immediately merge but flow while being split, so that twin vortices do not occur,
Instead, a small Karman vortex 22 is generated. In this state, the Karman vortex 22 comes into contact with the heating resistor 1 and flows backward with the Karman vortex 22.
【００５２】カルマン渦２２は、空気流が一定の状態に
あるときは充分に安定であり、発熱抵抗体１の熱伝達に
ばらつきをもたらす虞れ無く、むしろ双子渦の発生を抑
えるように働く。The Karman vortex 22 is sufficiently stable when the air flow is in a constant state, and there is no possibility that the heat transfer of the heating resistor 1 will vary, but rather, it acts to suppress the generation of twin vortices.
【００５３】また、このように、感温抵抗体２により分
流された結果、空気流は広がった状態で発熱抵抗体１に
接触するため、図示のように、発熱抵抗体１の全周を覆
うような流線を描いて発熱抵抗体１の後方にも流れ込む
ため、発熱抵抗体１のほぼ全周が空気流に対する伝熱面
２３として得られる。As described above, since the air flow contacts the heating resistor 1 in a spread state as a result of being divided by the temperature sensing resistor 2, the entire circumference of the heating resistor 1 is covered as shown in the figure. Since such a flow line is drawn and flows into the rear of the heating resistor 1, almost the entire circumference of the heating resistor 1 is obtained as the heat transfer surface 23 for the air flow.
【００５４】従って、空気流に対する伝熱促進が促さ
れ、安定した空気との熱伝達のやりとりを行うことがで
き、この結果、高い検出感度が容易に与えられ、高精度
の流量計測を確実に得ることができる。Accordingly, heat transfer to the air flow is promoted, and stable heat transfer with the air can be performed. As a result, high detection sensitivity is easily provided, and high-precision flow measurement can be reliably performed. Obtainable.
【００５５】なお、このような空気流中に配置された物
体に対して、その前方に障害物を配置することによる伝
熱促進の向上機能に関しては、日本機械学会学会論文集
５０−４５４、５１−４６７、５２−４７３、６１−５
８６(防衛大：五十嵐教授の論文)に詳細に報告されてお
り、従って、上記本発明の実施形態による効果は、充分
に実証されているものである。The function of enhancing the heat transfer by arranging an obstacle in front of such an object placed in the air flow is described in the Transactions of the Society of Mechanical Engineers of Japan 50-454, 51. -467, 52-473, 61-5
86 (Patent of Defense: Prof. Igarashi), and the effects of the embodiment of the present invention have been sufficiently demonstrated.
【００５６】[0056]
【発明の効果】本発明によれば、検出素子に対する塵埃
の堆積を確実に抑えることができるので、吸入空気流量
測定精度の経時変化の虞れがなく、検出誤差を常に最小
値に保つことができ、信頼性に優れた高精度の空気流量
測定装置を容易に提供することができる。According to the present invention, since the accumulation of dust on the detecting element can be reliably suppressed, there is no fear that the accuracy of measuring the intake air flow rate changes over time, and the detection error can always be kept at a minimum value. It is possible to easily provide a highly accurate and accurate air flow measuring device.
【図１】本発明による空気流量測定装置の一実施形態に
おける感温抵抗体と発熱抵抗体の配置状態を示す説明図
である。FIG. 1 is an explanatory diagram showing an arrangement state of a temperature-sensitive resistor and a heating resistor in an embodiment of an air flow measuring device according to the present invention.
【図２】本発明による空気流量測定装置の他の一実施形
態における感温抵抗体と発熱抵抗体の配置状態を示す説
明図である。FIG. 2 is an explanatory diagram showing an arrangement state of a temperature-sensitive resistor and a heating resistor in another embodiment of the air flow measuring device according to the present invention.
【図３】本発明による空気流量測定装置の一実施形態を
示す断面図である。FIG. 3 is a sectional view showing an embodiment of an air flow measuring device according to the present invention.
【図４】本発明による空気流量測定装置の一実施形態を
示す正面図である。FIG. 4 is a front view showing an embodiment of an air flow measuring device according to the present invention.
【図５】本発明による空気流量測定装置の一実施形態で
使用する発熱抵抗体と感温抵抗体の一例を示す断面図で
ある。FIG. 5 is a sectional view showing an example of a heating resistor and a temperature-sensitive resistor used in an embodiment of the air flow measuring device according to the present invention.
【図６】本発明による空気流量測定装置の一実施形態で
使用する発熱抵抗体と感温抵抗体の他の一例を示す断面
図である。FIG. 6 is a sectional view showing another example of a heating resistor and a temperature-sensitive resistor used in an embodiment of the air flow measuring device according to the present invention.
【図７】本発明による空気流量測定装置の一実施形態の
実装状態を示す説明図である。FIG. 7 is an explanatory diagram showing a mounted state of an embodiment of an air flow measuring device according to the present invention.
【図８】本発明の一実施形態による塵埃の堆積状態を示
す説明図である。FIG. 8 is an explanatory diagram showing a dust accumulation state according to an embodiment of the present invention.
【図９】本発明の実施形態の特性を従来技術の特性と比
較して示した特性図である。FIG. 9 is a characteristic diagram showing characteristics of the embodiment of the present invention in comparison with characteristics of the related art.
【図１０】本発明の一実施形態における空気流の状態を
示す説明図である。FIG. 10 is an explanatory diagram showing a state of an airflow in one embodiment of the present invention.
【図１１】従来技術における空気流の状態を示す説明図
である。FIG. 11 is an explanatory diagram showing a state of an air flow in the related art.
【図１２】従来技術における塵埃の堆積状態を示す説明
図である。FIG. 12 is an explanatory view showing a state of accumulation of dust in a conventional technique.
１ 発熱抵抗体 ２ 感温抵抗体 ３、４ ピン(支持用) ６ ボディ ７ 主空気通路 ８ 副空気通路 ９ 副空気通路部材 １０ 駆動回路(流量検出回路) １１ 円筒状部材(パイプ) １２ リード線 １３ 接合材 １４ 抵抗体部分 １５ コーティング １６ 抵抗体部分 １７ エアクリーナ １８ エアクリーナダクト ２０ 双子渦 ２１ 従来技術での発熱抵抗体の熱伝達面 ２２ カルマン渦 ２３ 本発明の実施形態での発熱抵抗体の熱伝達面 Ｄ 堆積物 DESCRIPTION OF SYMBOLS 1 Heating resistor 2 Temperature sensitive resistor 3 and 4 pins (for support) 6 Body 7 Main air passage 8 Sub air passage 9 Sub air passage member 10 Drive circuit (flow rate detection circuit) 11 Cylindrical member (pipe) 12 Lead wire DESCRIPTION OF SYMBOLS 13 Joining material 14 Resistor part 15 Coating 16 Resistor part 17 Air cleaner 18 Air cleaner duct 20 Twin vortex 21 Heat transfer surface of heating resistor in prior art 22 Karman vortex 23 Heat transfer of heating resistor in the embodiment of the present invention Surface D sediment
Claims (5)
の中に、該通路内での空気の流通方向の前後に配置した
発熱抵抗体と感温抵抗体を備えた発熱抵抗式の空気流量
測定装置において、 前記発熱抵抗体と前記感温抵抗体が、前記感温抵抗体が
前記通路内の空気の流れの前方に位置し、前記発熱抵抗
体が前記通路内の空気の流れの後方に位置するようにし
て、前記空気の流れの同一流線上に揃えて平行に配置し
たことを特徴とする空気流量測定装置。1. A heating resistor type air having a heating resistor and a temperature sensing resistor disposed before and after in a flow direction of air in a passage through which air whose flow rate is to be measured flows. In the flow rate measuring device, the heating resistor and the temperature-sensitive resistor may be arranged such that the temperature-sensitive resistor is located in front of the flow of air in the passage, and the heating resistor is located behind the flow of air in the passage. Wherein the air flow measuring device is arranged in parallel on the same streamline of the air flow.
量を計測すべき空気が通流される主空気通路の中に形成
されている副空気通路で構成されていることを特徴とす
る空気流量測定装置。2. The sub-air according to claim 1, wherein the passage in which the heating resistor and the temperature-sensitive resistor are arranged is formed in a main air passage through which air whose flow rate is to be measured flows. An air flow measuring device comprising a passage.
ｄ２としたとき、これら発熱抵抗体と感温抵抗体との間
隔Ｌについて、 Ｌ≧(ｄ１＋ｄ２)／２ の関係が成立するように構成したことを特徴とする空気
流量測定装置。3. The distance between the heating resistor and the temperature-sensitive resistor according to claim 1 or 2, wherein the diameter of the heating resistor is d1 and the diameter of the temperature-sensitive resistor is d2. An air flow measurement device, wherein L is configured to satisfy a relationship of L ≧ (d1 + d2) / 2.
径をｄ２としたとき、これら発熱抵抗体と感温抵抗体の
直径の比αについて、 α＝ｄ１／ｄ２＞１ の関係が成立するように構成したことを特徴とする空気
流量測定装置。4. The diameter of the heating resistor and the temperature-sensitive resistor according to claim 1 or 2, wherein the diameter of the heating resistor is d1, and the diameter of the temperature-sensitive resistor is d2. An air flow rate measuring device characterized in that the relationship α = d1 / d2> 1 is satisfied for the ratio α.
配置される感温抵抗体と発熱抵抗体において前記感温抵
抗体を規準とした際、発熱抵抗体の高さ方向の位置ばら
つきを±１ｍｍ以内にした構造を特徴とする空気流量測
定装置。5. The method according to claim 1, wherein the temperature-sensitive resistor and the heat-generating resistor arranged on the same streamline have a positional variation in the height direction of the heat-generating resistor when the temperature-sensitive resistor is used as a reference. An air flow measurement device characterized by a structure within ± 1 mm.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP10169818A JP2000002568A (en) | 1998-06-17 | 1998-06-17 | Air flow rate measuring apparatus |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP10169818A JP2000002568A (en) | 1998-06-17 | 1998-06-17 | Air flow rate measuring apparatus |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JP2000002568A true JP2000002568A (en) | 2000-01-07 |
Family
ID=15893476
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP10169818A Pending JP2000002568A (en) | 1998-06-17 | 1998-06-17 | Air flow rate measuring apparatus |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2000002568A (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2003014520A (en) * | 2001-07-04 | 2003-01-15 | Denso Corp | Air cleaner with built-in air flowmeter and adjusting method therefor |
| JP2009198248A (en) * | 2008-02-20 | 2009-09-03 | Denso Corp | Thermal type air flow meter |
-
1998
- 1998-06-17 JP JP10169818A patent/JP2000002568A/en active Pending
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2003014520A (en) * | 2001-07-04 | 2003-01-15 | Denso Corp | Air cleaner with built-in air flowmeter and adjusting method therefor |
| JP2009198248A (en) * | 2008-02-20 | 2009-09-03 | Denso Corp | Thermal type air flow meter |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| EP0023970B1 (en) | Air flow meter | |
| KR100251025B1 (en) | Flow rate detector | |
| US7775104B2 (en) | Thermal flowmeter in which relationship among length of heat resistor, heating temperature for the heat resistor, and power supplied to the heat resistor is prescribed | |
| US6253606B1 (en) | Thermosensitive flow rate sensor | |
| JP2001027558A (en) | Thermal type flowrate sensor | |
| JP3240733B2 (en) | Thermal air flow meter | |
| US4300391A (en) | Hot wire anemometer for measuring the flow velocity of gases and liquids (II) | |
| JP3484372B2 (en) | Thermal flow sensor | |
| JP3919829B2 (en) | Measuring device for measuring the mass of a medium flowing in a conduit | |
| JP3770369B2 (en) | Flow rate and flow rate measuring device | |
| JP2010181354A (en) | Airflow rate measuring device | |
| US6170327B1 (en) | Air mass meter | |
| JP2000002568A (en) | Air flow rate measuring apparatus | |
| JP3671393B2 (en) | Thermal flow sensor | |
| JP2002530244A (en) | An improved probe for measuring physical parameters of fluid flow. | |
| US7051589B2 (en) | Heating resistor flow rate measuring instrument | |
| US4761995A (en) | Direct-heated flow measuring apparatus having improved sensitivity and response speed | |
| US4434656A (en) | Mass air flow sensor | |
| JP5542614B2 (en) | Flow measuring device | |
| JP5272801B2 (en) | Air flow measurement device | |
| JP4909561B2 (en) | Heating resistor type air flow measuring device | |
| JP3064128B2 (en) | Air flow meter | |
| JP3378833B2 (en) | Heating resistor type air flow measurement device | |
| JP2002005710A (en) | Bypass type measuring device for flow and flow velocity in pipe of small diameter | |
| JP2533479B2 (en) | Heating resistance type air flow meter |