JP4968267B2 - Air flow measurement device - Google Patents

Air flow measurement device Download PDF

Info

Publication number
JP4968267B2
JP4968267B2 JP2009001510A JP2009001510A JP4968267B2 JP 4968267 B2 JP4968267 B2 JP 4968267B2 JP 2009001510 A JP2009001510 A JP 2009001510A JP 2009001510 A JP2009001510 A JP 2009001510A JP 4968267 B2 JP4968267 B2 JP 4968267B2
Authority
JP
Japan
Prior art keywords
sub
flow
air
flow rate
channel
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.)
Active
Application number
JP2009001510A
Other languages
Japanese (ja)
Other versions
JP2010160013A (en
Inventor
昇 北原
信一 神谷
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Denso Corp
Original Assignee
Denso Corp
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Denso Corp filed Critical Denso Corp
Priority to JP2009001510A priority Critical patent/JP4968267B2/en
Priority to DE102010000692.0A priority patent/DE102010000692B4/en
Publication of JP2010160013A publication Critical patent/JP2010160013A/en
Application granted granted Critical
Publication of JP4968267B2 publication Critical patent/JP4968267B2/en
Active legal-status Critical Current
Anticipated expiration legal-status Critical

Links

Images

Classifications

    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01F—MEASURING VOLUME, VOLUME FLOW, MASS FLOW OR LIQUID LEVEL; METERING BY VOLUME
    • G01F1/00—Measuring the volume flow or mass flow of fluid or fluent solid material wherein the fluid passes through a meter in a continuous flow
    • G01F1/68—Measuring the volume flow or mass flow of fluid or fluent solid material wherein the fluid passes through a meter in a continuous flow by using thermal effects
    • G01F1/684—Structural arrangements; Mounting of elements, e.g. in relation to fluid flow
    • G01F1/6842—Structural arrangements; Mounting of elements, e.g. in relation to fluid flow with means for influencing the fluid flow
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01F—MEASURING VOLUME, VOLUME FLOW, MASS FLOW OR LIQUID LEVEL; METERING BY VOLUME
    • G01F1/00—Measuring the volume flow or mass flow of fluid or fluent solid material wherein the fluid passes through a meter in a continuous flow
    • G01F1/68—Measuring the volume flow or mass flow of fluid or fluent solid material wherein the fluid passes through a meter in a continuous flow by using thermal effects
    • G01F1/684—Structural arrangements; Mounting of elements, e.g. in relation to fluid flow
    • G01F1/688—Structural arrangements; Mounting of elements, e.g. in relation to fluid flow using a particular type of heating, cooling or sensing element
    • G01F1/69—Structural arrangements; Mounting of elements, e.g. in relation to fluid flow using a particular type of heating, cooling or sensing element of resistive type
    • G01F1/692—Thin-film arrangements

Landscapes

  • Physics & Mathematics (AREA)
  • Fluid Mechanics (AREA)
  • General Physics & Mathematics (AREA)
  • Measuring Volume Flow (AREA)

Description

本発明は、ダクトの内部を流れる空気の一部を取り込む副流路と、この副流路を流れる空気の一部を取り込む副副流路とを有し、この副副流路に配設される流量センサによって空気流量を測定する空気流量測定装置に関する。   The present invention has a sub-flow channel that takes in part of the air flowing inside the duct and a sub-sub-flow channel that takes in part of the air flowing through the sub-flow channel, and is arranged in the sub-sub flow channel. The present invention relates to an air flow rate measuring apparatus that measures an air flow rate with a flow rate sensor.

従来、自動車用エンジンの吸入空気量を測定するエアフロメータには、半導体基板の表面に薄膜抵抗体で形成された発熱体を設けた薄膜式の流量センサを用いたものが知られている。この薄膜式の流量センサは、空気中に含まれるダスト等の衝突によって基板上の薄膜抵抗体（発熱体）がダメージを受ける恐れがある。
そこで、特許文献１に開示される従来技術では、図３に示す様に、ダクト１００の内部に配置されるセンサボディ１１０に空気の一部を取り込む副流路１２０を形成し、さらに、副流路１２０を流れる空気の一部を取り込む副副流路１３０を形成して、この副副流路１３０に流量センサ１４０を配設している。この構成によれば、センサボディ１１０の上流から流れてくる空気中にダストが含まれている場合でも、そのダストの多くが副流路１２０を通り抜けてセンサボディ１１０の下流側へ流れるため、副流路１２０から副副流路１３０へダストが流れ込むことを抑制できる。これにより、流量センサ１４０にダストが衝突することを抑制できるので、流量センサ１４０に設けられる発熱体（薄膜抵抗体）がダメージを受けることを回避できる。 2. Description of the Related Art Conventionally, an air flow meter that measures an intake air amount of an automobile engine uses a thin film type flow sensor in which a heating element formed of a thin film resistor is provided on the surface of a semiconductor substrate. In this thin film type flow sensor, the thin film resistor (heating element) on the substrate may be damaged by the collision of dust or the like contained in the air.
Therefore, in the prior art disclosed in Patent Document 1, as shown in FIG. 3, a sub-flow channel 120 that takes in a part of air is formed in the sensor body 110 arranged inside the duct 100, and the sub-flow A sub-sub-flow channel 130 that takes in part of the air flowing through the passage 120 is formed, and a flow sensor 140 is disposed in the sub-sub-channel 130. According to this configuration, even when dust is contained in the air flowing from the upstream side of the sensor body 110, most of the dust flows through the secondary flow path 120 to the downstream side of the sensor body 110. The dust can be prevented from flowing from the flow channel 120 to the sub-sub flow channel 130. Thereby, since it can suppress that dust collides with the flow sensor 140, it can avoid that the heat generating body (thin film resistor) provided in the flow sensor 140 receives damage.

ところで、上記のエアフロメータは、流量センサ１４０の発熱体が配線を介して回路部１５０と電気的に接続されている。回路部１５０は、発熱体への通電電流を制御すると共に、流量センサ１４０で測定される空気流量を流量信号として出力する働きを有している。しかし、この回路部１５０は、外部との電気的接続を行うコネクタと一体に設けられてダクト１００の外側に配置されている。このため、特許文献１に開示されたエアフロメータは、ダクト１００の外部に突き出る部分が大きくなり、エンジンルーム内でのスペース確保が困難となる。
そこで、例えば、図４に示す様に、センサボディ１１０の内部に回路部１５０を組み込んだエアフロメータが提案されている（特許文献２参照）。このエアフロメータは、ダクト１００の外側にコネクタ１６０だけを配置すれば良いので、エンジンルーム内でのスペース確保を容易にできる。 By the way, in the air flow meter described above, the heating element of the flow sensor 140 is electrically connected to the circuit unit 150 via wiring. The circuit unit 150 has a function of controlling an energization current to the heating element and outputting an air flow rate measured by the flow rate sensor 140 as a flow rate signal. However, the circuit unit 150 is provided integrally with a connector for electrical connection with the outside, and is disposed outside the duct 100. For this reason, the air flow meter disclosed in Patent Document 1 has a large portion protruding to the outside of the duct 100, making it difficult to secure a space in the engine room.
Therefore, for example, as shown in FIG. 4, an air flow meter in which a circuit unit 150 is incorporated in the sensor body 110 has been proposed (see Patent Document 2). In this air flow meter, since only the connector 160 needs to be disposed outside the duct 100, it is possible to easily secure a space in the engine room.

特開２００５−１４０７５３号公報Japanese Patent Laying-Open No. 2005-140753 特開２００２−３３２９０７号公報JP 2002-332907 A

しかし、図４に示すエアフロメータでは、センサボディ１１０の内部に回路部１５０を配設するための専用のスペースを設ける必要があるため、センサボディ１１０の体格が大きくなってしまう。この場合、センサボディ１１０をダクト１００の内部へ挿入するためにダクト１００に開けられる孔の内径を大きくする必要が生じるため、従来のダクトをそのまま（孔の内径を変えることなく）使用することはできない。また、孔の内径を大きくすると、ダクト１００の長さにも影響するため、ダクト１００の接続や取り回しが困難になる。   However, in the air flow meter shown in FIG. 4, it is necessary to provide a dedicated space for disposing the circuit unit 150 inside the sensor body 110, so that the size of the sensor body 110 becomes large. In this case, in order to insert the sensor body 110 into the duct 100, it is necessary to increase the inner diameter of the hole opened in the duct 100. Therefore, using the conventional duct as it is (without changing the inner diameter of the hole) Can not. Further, if the inner diameter of the hole is increased, the length of the duct 100 is also affected, so that the connection and handling of the duct 100 becomes difficult.

さらには、センサボディ１１０の内部に回路部１５０を組み込むことで、副流路１２０の他に副副流路１３０を形成することが困難となり、図４に示すエアフロメータでは、副流路１２０のみが形成されている。このため、副流路１２０に配置される流量センサにダストが衝突することを回避することは困難であり、特に、薄膜式の流量センサを用いた場合は、発熱体（薄膜抵抗体）がダメージを受けるという問題がある。
本発明は、上記事情に基づいて成されたもので、その目的は、センサボディの内部に回路部を組み込んだ構成であって、センサボディの体格が大型化することなく、且つ、流量センサにダストが衝突することを抑制できる空気流量測定装置を提供することにある。 Furthermore, by incorporating the circuit unit 150 in the sensor body 110, it becomes difficult to form the sub-sub-channel 130 in addition to the sub-channel 120. In the air flow meter shown in FIG. Is formed. For this reason, it is difficult to avoid dust from colliding with the flow rate sensor disposed in the sub-flow channel 120. In particular, when a thin film type flow rate sensor is used, the heating element (thin film resistor) is damaged. There is a problem of receiving.
The present invention has been made on the basis of the above circumstances, and its purpose is a configuration in which a circuit unit is incorporated in the sensor body, and the flow sensor is not increased in size and without increasing the size of the sensor body. An object of the present invention is to provide an air flow rate measuring device capable of suppressing dust from colliding.

（請求項１の発明）
本発明は、ダクトの内部を流れる空気の一部を取り込む副流路と、この副流路を流れる空気の一部を取り込む副副流路と、通電によって発熱する発熱抵抗体を有し、この発熱抵抗体により生じる温度分布を基に副副流路を流れる空気流量を測定する流量センサと、発熱抵抗体への通電電流を制御する働きを有する回路部とを備え、この回路部が副副流路に配設され、副副流路を流れる空気の流れに晒されていることを特徴とする。
上記の構成によれば、センサボディの内部に回路部を配設するための専用のスペースを設ける必要がないので、センサボディの体格が大型化することはない。また、センサボディの内部に副副流路を形成するためのスペースが減少することもない。その結果、副副流路の流路損失が増大することもなく、副副流路を流れる空気流量を精度良く測定できる。 さらに、副副流路に回路部を配設することにより、副副流路を流れる空気によって回路部を冷却できるため、回路部に対する放熱性が向上する。 (Invention of Claim 1)
The present invention has a sub-flow channel that takes in a part of the air flowing inside the duct, a sub-sub-flow channel that takes in a part of the air flowing through the sub-flow channel, and a heating resistor that generates heat when energized. A flow rate sensor that measures the flow rate of air flowing through the auxiliary and sub-channels based on the temperature distribution generated by the heating resistor, and a circuit unit that functions to control the current flowing to the heating resistor. It is arrange | positioned at a flow path and is exposed to the flow of the air which flows through a sub-sub-flow path, It is characterized by the above-mentioned.
According to the above configuration, there is no need to provide a dedicated space for arranging the circuit portion inside the sensor body, so that the size of the sensor body does not increase. Further, the space for forming the sub-sub channel in the sensor body is not reduced. As a result, the flow rate of the air flowing through the sub-sub-channel can be accurately measured without increasing the channel loss of the sub-sub-channel. Furthermore, since the circuit unit can be cooled by the air flowing through the sub-sub channel by disposing the circuit unit in the sub-sub channel, the heat dissipation performance for the circuit unit is improved.

（請求項２の発明）
請求項１に記載した空気流量測定装置において、流量センサは、半導体基板の表面上に発熱抵抗体が薄膜抵抗体で形成されていることを特徴とする。
本発明に係る空気流量測定装置は、副副流路に流量センサを配設しているので、空気中にダストが含まれている場合でも、副流路から副副流路へダストが流れ込むことを抑制できる。これにより、発熱抵抗体を薄膜抵抗体で形成した薄膜式の流量センサを用いた場合でも、その流量センサにダストが衝突することを抑制できるので、発熱体（薄膜抵抗体）がダメージを受けることを回避できる。 (Invention of Claim 2)
In the air flow rate measuring apparatus according to claim 1, the flow rate sensor is characterized in that the heating resistor is formed of a thin film resistor on the surface of the semiconductor substrate.
In the air flow rate measuring device according to the present invention, since the flow sensor is disposed in the sub-sub-flow channel, even if dust is contained in the air, the dust flows into the sub-sub-flow channel. Can be suppressed. As a result, even when a thin film type flow sensor in which the heating resistor is formed of a thin film resistor is used, it is possible to suppress dust from colliding with the flow sensor, so that the heating element (thin film resistor) is damaged. Can be avoided.

（請求項３の発明）
請求項１または２に記載した空気流量測定装置において、流量センサは、副副流路の回路部より上流側に配置されていることを特徴とする。
副副流路を流れる空気の流れ方向において、回路部の方が流量センサより上流側に配置されていると、副流路から副副流路に取り込まれた空気が回路部を通過する際に、空気の流れに乱れが生じて、流量センサでの流量測定に悪影響を生じる恐れがある。
これに対し、本発明では、流量センサの方が回路部より上流側に配置されているので、副流路から副副流路に取り込まれた空気の流れが大きく乱れることはなく、流量センサの測定精度を向上できる。 (Invention of Claim 3)
The air flow rate measuring device according to claim 1 or 2, wherein the flow rate sensor is arranged on the upstream side of the circuit portion of the sub-sub-flow channel.
When the circuit part is arranged upstream of the flow rate sensor in the flow direction of the air flowing through the sub-sub-flow path, when the air taken into the sub-sub-flow path from the sub-flow path passes through the circuit part. The air flow may be disturbed, and the flow rate measurement by the flow rate sensor may be adversely affected.
On the other hand, in the present invention, since the flow sensor is arranged on the upstream side of the circuit unit, the flow of air taken from the sub-flow path to the sub-sub-flow path is not greatly disturbed, and the flow sensor Measurement accuracy can be improved.

（ａ）エアフロメータの断面図、（ｂ）同エアフロメータのＡ−Ａ断面図である。(A) It is sectional drawing of an air flow meter, (b) It is AA sectional drawing of the air flow meter. （ａ）流量センサの断面図、（ｂ）流量センサの平面図、（ｃ）流量センサに発生する温度分布図である。(A) Cross-sectional view of flow sensor, (b) Plan view of flow sensor, (c) Temperature distribution generated in flow sensor. 従来技術に係るエアフロメータの断面図である。It is sectional drawing of the air flow meter which concerns on a prior art. 従来技術に係るエアフロメータの断面図である。It is sectional drawing of the air flow meter which concerns on a prior art.

本発明を実施するための最良の形態を以下の実施例により詳細に説明する。   The best mode for carrying out the present invention will be described in detail with reference to the following examples.

実施例１に示す空気流量測定装置は、例えば、自動車用エンジンの吸入空気量を測定するエアフロメータ１であり、エアクリーナ（図示せず）のアウトレットパイプ（以下ダクト２と呼ぶ）にプラグイン方式によって着脱可能に取り付けられている。このエアフロメータ１は、以下に説明するセンサボディ３、流量センサ４、および回路部５等より構成される。
センサボディ３は、図１に示す様に、ダクト２に形成された取付け孔よりダクト２の内部に挿入され、Ｏリング６によって取付け孔との間が気密にシールされている。このセンサボディ３には、図１（ａ）に示す様に、ダクト２の内部を図示左側から右側に向かって流れる空気、つまり、エアクリーナで濾過されてエンジンに吸入される空気の一部を取り込む副流路７と、この副流路７を流れる空気の一部を取り込む副副流路８とが形成されている。 The air flow measuring device shown in the first embodiment is, for example, an air flow meter 1 that measures the intake air amount of an automobile engine, and is plugged into an outlet pipe (hereinafter referred to as a duct 2) of an air cleaner (not shown). Removably attached. The air flow meter 1 includes a sensor body 3, a flow rate sensor 4, a circuit unit 5, and the like described below.
As shown in FIG. 1, the sensor body 3 is inserted into the duct 2 through an attachment hole formed in the duct 2, and is hermetically sealed with the O-ring 6. As shown in FIG. 1A, the sensor body 3 takes in the air flowing in the duct 2 from the left side to the right side, that is, a part of the air filtered by the air cleaner and sucked into the engine. A sub-channel 7 and a sub-channel 8 that takes in part of the air flowing through the sub-channel 7 are formed.

副流路７は、センサボディ３の先端部において、センサボディ３の上流端面に開口する入口７ａから、センサボディ３の下流端面に開口する出口７ｂまで、センサボディ３の内部を横幅方向に貫通して形成されている。つまり、副流路７は、ダクト２の内部を流れる空気の流れ方向と略平行に形成されている。
副副流路８は、センサボディ３の内部を上下方向に延びて形成され、且つ、センサボディ３の上部に空気の流れ方向が１８０度変化するＵターン部を有している。すなわち、Ｕターン部より上流側の流路（流入路と呼ぶ）と、Ｕターン部より下流側の流路（流出路と呼ぶ）とを有し、流入路の上流端が副流路７に連通して形成され、流出路の下流端が、センサボディ３の両側面に形成される出口３ａに連通して形成されている。従って、副流路７を流れる空気の一部は、副流路７から流入路を流れてＵターン部で折り返した後、流出路を流れて出口３ａより流出する。 The auxiliary flow path 7 penetrates the inside of the sensor body 3 in the lateral width direction from the inlet 7a that opens to the upstream end face of the sensor body 3 to the outlet 7b that opens to the downstream end face of the sensor body 3 at the distal end of the sensor body 3. Is formed. That is, the sub flow path 7 is formed substantially parallel to the flow direction of the air flowing inside the duct 2.
The sub-sub flow channel 8 is formed extending in the vertical direction inside the sensor body 3, and has a U-turn portion at the top of the sensor body 3 where the air flow direction changes by 180 degrees. That is, it has a flow path upstream of the U-turn part (referred to as an inflow path) and a flow path downstream of the U-turn part (referred to as an outflow path). The downstream end of the outflow passage is formed in communication with outlets 3 a formed on both side surfaces of the sensor body 3. Accordingly, a part of the air flowing through the sub-flow channel 7 flows from the sub-flow channel 7 through the inflow path and is folded at the U-turn portion, then flows through the outflow path and flows out from the outlet 3a.

流量センサ４は、副副流路８のＵターン部より上流側、つまり、流入路の途中に配設されている。この流量センサ４は、図２（ａ）に示す様に、例えば、シリコン基板４０の表面上に空気の流れ方向と略平行に設けられる絶縁膜４１と、この絶縁膜４１の表面上に形成される発熱抵抗体４２と、絶縁膜４１の表面上で発熱抵抗体４２の上流側に設けられる上流側検出抵抗４３および発熱抵抗体４２の下流側に設けられる下流側検出抵抗４４とを有し、この発熱抵抗体４２と上流側検出抵抗４３および下流側検出抵抗４４の上部が保護膜４５（例えば、窒化シリコン層）によって覆われている。
シリコン基板４０には、例えば、異方性エッチングにより、シリコン基板４０の裏面から絶縁膜４１との境界面まで、シリコン基板４０の一部が除去されて、空洞部４０ａが形成されている。 The flow rate sensor 4 is disposed on the upstream side of the U-turn portion of the sub-sub channel 8, that is, in the middle of the inflow path. As shown in FIG. 2A, the flow sensor 4 is formed, for example, on the surface of the silicon substrate 40 and the insulating film 41 provided substantially in parallel with the air flow direction, and on the surface of the insulating film 41. A heating resistor 42, an upstream detection resistor 43 provided on the upstream side of the heating resistor 42 on the surface of the insulating film 41, and a downstream detection resistor 44 provided on the downstream side of the heating resistor 42, Upper portions of the heating resistor 42, the upstream detection resistor 43, and the downstream detection resistor 44 are covered with a protective film 45 (for example, a silicon nitride layer).
In the silicon substrate 40, for example, a part of the silicon substrate 40 is removed from the back surface of the silicon substrate 40 to the boundary surface with the insulating film 41 by anisotropic etching to form a cavity 40a.

絶縁膜４１は、例えば、窒化シリコン層によって形成され、シリコン基板４０の表面にスパッタ法あるいはＣＶＤ法等により設けられている。
発熱抵抗体４２と上流側検出抵抗４３および下流側検出抵抗４４は、例えば、絶縁膜４１の表面に白金等の感熱抵抗膜を真空蒸着法等により堆積させた後、エッチング処理により不要な部分が除去されて、それぞれ、図２（ｂ）に示す様に、所定の形状に形成されている。この発熱抵抗体４２と上流側検出抵抗４３および下流側検出抵抗４４は、回路部５と電気的に接続され、回路部５より発熱抵抗体４２が通電されて加熱制御される。上流側検出抵抗４３と下流側検出抵抗４４は、それぞれ、温度に応じて抵抗値が変化する。 The insulating film 41 is formed of, for example, a silicon nitride layer, and is provided on the surface of the silicon substrate 40 by sputtering or CVD.
The heating resistor 42, the upstream detection resistor 43, and the downstream detection resistor 44 have unnecessary portions formed by, for example, etching after depositing a heat sensitive resistance film such as platinum on the surface of the insulating film 41 by a vacuum deposition method or the like. As shown in FIG. 2B, they are removed and formed into predetermined shapes. The heating resistor 42, the upstream detection resistor 43, and the downstream detection resistor 44 are electrically connected to the circuit unit 5, and the heating resistor 42 is energized from the circuit unit 5 to be heated. The resistance values of the upstream detection resistor 43 and the downstream detection resistor 44 change according to the temperature.

この流量センサ４による空気流量の測定方法について説明する。
発熱抵抗体４２が通電されて発熱すると、例えば、図２（ｂ）に示す絶縁膜４１の表面上の固定軸Ｘにおいて、図２（ｃ）に示す様に、空気の流れ方向に沿った温度分布が形成される。これにより、固定軸Ｘと交差する上流側検出抵抗４３の交差部Ｘ１と、固定軸Ｘと交差する下流側検出抵抗４４の交差部Ｘ２との間に、温度に関して差分δが発生する。この差分δを図示長手方向に平均化して、上流側検出抵抗４３と下流側検出抵抗４４との間の検出差分Δが得られ、この検出差分Δに基づいて空気流量が検出される。 A method for measuring the air flow rate by the flow sensor 4 will be described.
When the heating resistor 42 is energized to generate heat, for example, the temperature along the air flow direction as shown in FIG. 2C at the fixed axis X on the surface of the insulating film 41 shown in FIG. A distribution is formed. As a result, a difference δ is generated with respect to the temperature between the intersection X1 of the upstream detection resistor 43 intersecting the fixed axis X and the intersection X2 of the downstream detection resistor 44 intersecting the fixed axis X. This difference δ is averaged in the illustrated longitudinal direction to obtain a detection difference Δ between the upstream detection resistor 43 and the downstream detection resistor 44, and the air flow rate is detected based on the detection difference Δ.

回路部５は、発熱抵抗体４２を加熱制御すると共に、上流側検出抵抗４３と下流側検出抵抗４４との間に得られる検出差分Δを流量信号として、例えば、電圧あるいは周波数等に変換して出力する機能を有している。この回路部５は、図１（ａ）に示す様に、副副流路８のＵターン部より下流側、つまり、流出路の途中に配設され、ダクト２の外部に取り出されるコネクタ９にターミナル５ａを介して接続されている。また、回路部５は、図１（ｂ）に示す様に、流出路の幅方向（図示左右方向）の中央部に配置され、回路部５の両側を空気が流れることができる。すなわち、流出路を流れる空気は、図示矢印で示す様に、回路部５の両側を通り抜けて出口３ａより流出する。なお、流量センサ４と回路部５は、両者が一体化されてサブアセンブリとして構成されている。   The circuit unit 5 controls the heating of the heating resistor 42 and converts the detection difference Δ obtained between the upstream detection resistor 43 and the downstream detection resistor 44 into, for example, a voltage or a frequency as a flow signal. It has a function to output. As shown in FIG. 1A, the circuit portion 5 is disposed downstream of the U-turn portion of the sub-sub-flow channel 8, that is, in the middle of the outflow path, and is connected to the connector 9 taken out of the duct 2. It is connected via the terminal 5a. Moreover, the circuit part 5 is arrange | positioned in the center part of the width direction (illustration left-right direction) of an outflow channel, as shown in FIG.1 (b), and air can flow the both sides of the circuit part 5. FIG. That is, the air flowing through the outflow passage passes through both sides of the circuit portion 5 and flows out from the outlet 3a as shown by the arrows in the drawing. The flow sensor 4 and the circuit unit 5 are integrated as a subassembly.

（実施例１の作用および効果）
なお、エアフロメータ１の作動は従来周知の通りであり、説明を省略する。
本実施例のエアフロメータ１は、回路部５をセンサボディ３の内部に組み込んでいるので、ダクト２の外側に回路部５を取り出して配置する必要はない。これにより、ダクト２の外側にコネクタ９だけを配置すれば良いので、エンジンルーム内でのスペース確保を容易にできる。
また、回路部５は、副副流路８の流出路に配設しているので、センサボディ３の内部に回路部５を配設するための専用のスペースを設ける必要はなく、センサボディ３の体格が大型化することはない。その結果、ダクト２に開ける取付け孔の内径を大きくする必要がないので、従来のダクトをそのまま使用できる。 (Operation and Effect of Example 1)
The operation of the air flow meter 1 is well known in the art and will not be described.
Since the air flow meter 1 of the present embodiment incorporates the circuit unit 5 inside the sensor body 3, it is not necessary to take out and arrange the circuit unit 5 outside the duct 2. As a result, only the connector 9 needs to be disposed outside the duct 2, so that it is easy to secure a space in the engine room.
Further, since the circuit unit 5 is arranged in the outflow path of the sub-sub channel 8, there is no need to provide a dedicated space for arranging the circuit unit 5 inside the sensor body 3, and the sensor body 3 The physique will not increase in size. As a result, since it is not necessary to increase the inner diameter of the mounting hole opened in the duct 2, the conventional duct can be used as it is.

本実施例のエアフロメータ１は、センサボディ３の内部に回路部５を組み込む構成であっても、センサボディ３の内部に副副流路８を形成するためのスペースが減少することはない。つまり、回路部５を副副流路８の流出路に配設するので、上記の如く、センサボディ３の内部に回路部５を配設するための専用のスペースを設ける必要はない。このため、回路部５の配置によって副副流路８の形状が影響を受けることはない。これにより、副副流路８の流路損失が増大することはないので、副副流路８を流れる空気流量を流量センサ４によって精度良く測定できる。
さらに、本実施例の回路部５は、流出路の幅方向の中央部に配設されるので、流出路を空気が流れる際に、回路部５の両側を空気が通り抜けて出口３ａより流出できる。すなわち、回路部５は、流出路を流れる空気の流れに晒されているので、その流出路を流れる空気によって回路部５を効果的に冷却できるため、回路部５に対する放熱性が向上する。 Even if the air flow meter 1 of the present embodiment is configured to incorporate the circuit unit 5 in the sensor body 3, the space for forming the sub-sub flow channel 8 in the sensor body 3 is not reduced. That is, since the circuit unit 5 is disposed in the outflow path of the sub-sub-channel 8, there is no need to provide a dedicated space for disposing the circuit unit 5 inside the sensor body 3 as described above. For this reason, the shape of the secondary / sub-channel 8 is not affected by the arrangement of the circuit unit 5. As a result, the flow loss of the auxiliary / sub-channel 8 does not increase, and the flow rate of air flowing through the auxiliary / sub-channel 8 can be accurately measured by the flow sensor 4.
Furthermore, since the circuit unit 5 of the present embodiment is disposed at the center portion in the width direction of the outflow path, when air flows through the outflow path, the air passes through both sides of the circuit section 5 and can flow out from the outlet 3a. . That is, since the circuit unit 5 is exposed to the flow of air flowing through the outflow path, the circuit unit 5 can be effectively cooled by the air flowing through the outflow path, so that the heat dissipation to the circuit unit 5 is improved.

本実施例のエアフロメータ１は、副流路７を流れる空気の一部を取り込む副副流路８が設けられ、この副副流路８が副流路７に対し略直交して形成されている。この構成によれば、ダクト２の内部を流れる空気中にダストが含まれている場合、つまり、エアクリーナで除去できなかったダストが空気中に含まれる場合でも、そのダストの多くは、ダクト２の軸心方向に沿って形成される副流路７を通り抜けるため、副流路７から副副流路８へダストが流れ込むことを抑制できる。これにより、副副流路８に配設された流量センサ４にダストが衝突することを抑制できるので、流量センサ４がダメージを受けることを回避できる。
また、本実施例の流量センサ４は、副副流路８を流れる空気の流れ方向において、回路部５より上流側に配置されているので、副流路７から副副流路８に取り込まれた空気の流れが大きく乱れることはなく、流量センサ４の測定精度を向上できる。 The air flow meter 1 of the present embodiment is provided with a sub-sub flow channel 8 that takes in part of the air flowing through the sub-flow channel 7, and the sub-sub flow channel 8 is formed substantially orthogonal to the sub-flow channel 7. Yes. According to this configuration, even when dust is contained in the air flowing inside the duct 2, that is, when dust that could not be removed by the air cleaner is contained in the air, most of the dust is in the duct 2. Since it passes through the auxiliary flow path 7 formed along the axial direction, it is possible to suppress dust from flowing from the auxiliary flow path 7 into the auxiliary auxiliary flow path 8. Thereby, since it can suppress that a dust collides with the flow sensor 4 arrange | positioned in the sub-sub-flow path 8, it can avoid that the flow sensor 4 receives a damage.
Further, since the flow sensor 4 of the present embodiment is disposed upstream of the circuit unit 5 in the flow direction of the air flowing through the sub-sub-flow channel 8, it is taken into the sub-sub-channel 8 from the sub-channel 7. The air flow is not significantly disturbed, and the measurement accuracy of the flow sensor 4 can be improved.

１ エアフロメータ（空気流量測定装置）
２ ダクト
４ 流量センサ
５ 回路部
７ 副流路
８ 副副流路
４２ 発熱抵抗体 1 Air flow meter (air flow measuring device)
2 Duct 4 Flow sensor 5 Circuit part 7 Sub flow path 8 Sub sub flow path 42 Heating resistor

Claims (3)

ダクトの内部を流れる空気の一部を取り込む副流路と、
この副流路を流れる空気の一部を取り込む副副流路と、
通電によって発熱する発熱抵抗体を有し、この発熱抵抗体により生じる温度分布を基に前記副副流路を流れる空気流量を測定する流量センサと、
前記発熱抵抗体への通電電流を制御する働きを有する回路部とを備え、この回路部が前記副副流路に配設され、前記副副流路を流れる空気の流れに晒されていることを特徴とする空気流量測定装置。 A sub-flow channel that takes in part of the air flowing inside the duct;
A sub-sub-passage that takes in part of the air flowing through the sub-passage;
A flow sensor that has a heating resistor that generates heat when energized, and that measures the flow rate of air flowing through the sub-sub-flow path based on a temperature distribution generated by the heating resistor;
A circuit unit having a function of controlling an energization current to the heating resistor, the circuit unit being disposed in the sub-sub-flow channel and exposed to the air flow flowing through the sub-sub-flow channel. An air flow rate measuring device characterized by. 請求項１に記載した空気流量測定装置において、
前記流量センサは、半導体基板の表面上に前記発熱抵抗体が薄膜抵抗体で形成されていることを特徴とする空気流量測定装置。 In the air flow rate measuring device according to claim 1,
The air flow rate measuring device according to claim 1, wherein the heating resistor is formed of a thin film resistor on a surface of a semiconductor substrate. 請求項１または２に記載した空気流量測定装置において、
前記流量センサは、前記副副流路の前記回路部より上流側に配設されていることを特徴とする空気流量測定装置。 In the air flow rate measuring device according to claim 1 or 2,
The air flow rate measuring device, wherein the flow rate sensor is disposed upstream of the circuit portion of the sub-sub-flow channel.
JP2009001510A 2009-01-07 2009-01-07 Air flow measurement device Active JP4968267B2 (en)

Priority Applications (2)

Application Number Priority Date Filing Date Title
JP2009001510A JP4968267B2 (en) 2009-01-07 2009-01-07 Air flow measurement device
DE102010000692.0A DE102010000692B4 (en) 2009-01-07 2010-01-05 air flow measuring device

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP2009001510A JP4968267B2 (en) 2009-01-07 2009-01-07 Air flow measurement device

Publications (2)

Publication Number Publication Date
JP2010160013A JP2010160013A (en) 2010-07-22
JP4968267B2 true JP4968267B2 (en) 2012-07-04

Family

ID=42371859

Family Applications (1)

Application Number Title Priority Date Filing Date
JP2009001510A Active JP4968267B2 (en) 2009-01-07 2009-01-07 Air flow measurement device

Country Status (2)

Country Link
JP (1) JP4968267B2 (en)
DE (1) DE102010000692B4 (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US11353350B2 (en) 2017-09-29 2022-06-07 Hitachi Astemo, Ltd. Physical quantity detection device

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2018138967A1 (en) 2017-01-26 2018-08-02 日立オートモティブシステムズ株式会社 Thermal flowmeter

Family Cites Families (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2846518B2 (en) 1992-03-18 1999-01-13 株式会社日立製作所 Air flow detector and engine control device using the same
DE19815654A1 (en) * 1998-04-08 1999-10-14 Bosch Gmbh Robert Measuring device for measuring the mass of a medium flowing in a line
JP3716163B2 (en) * 2000-06-16 2005-11-16 株式会社日立製作所 Air flow measurement device
JP3785338B2 (en) * 2001-07-25 2006-06-14 株式会社日立製作所 Thermal flow meter
JP3866995B2 (en) 2002-03-18 2007-01-10 株式会社日立製作所 Thermal air flow meter for internal combustion engines
JP2005140753A (en) 2003-11-10 2005-06-02 Mitsubishi Electric Corp Apparatus for measuring quantity of air sucked in internal combustion engine
DE102004021304B4 (en) 2004-04-29 2018-12-13 Abb Ag Flowmeter

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US11353350B2 (en) 2017-09-29 2022-06-07 Hitachi Astemo, Ltd. Physical quantity detection device
DE112018003394B4 (en) 2017-09-29 2024-09-05 Hitachi Astemo, Ltd. Detection device for physical quantities

Also Published As

Publication number Publication date
DE102010000692B4 (en) 2022-10-13
JP2010160013A (en) 2010-07-22
DE102010000692A1 (en) 2010-09-02

Similar Documents

Publication Publication Date Title
JP3553422B2 (en) Flow sensor
JP5445535B2 (en) Air flow measurement device
JP5182314B2 (en) Air flow measurement device
JP5170209B2 (en) Flow measuring device
US6079264A (en) Thermal flow sensor supporting element having a gradually increased portion between its distal ends
JPH116752A (en) Thermal-type air flow-rate sensor
WO2012014956A1 (en) Thermal flow meter
JP6073489B2 (en) Air mass flow meter with sensor element
US10371076B2 (en) Intake air flow rate measuring device
JP4752472B2 (en) Air flow measurement device
JP4968267B2 (en) Air flow measurement device
JP5223708B2 (en) Air flow measurement device
JP4166705B2 (en) Air flow measurement device
JP2010204005A (en) Thermal flowmeter
JP5455848B2 (en) Thermal flow sensor
JP4089654B2 (en) Air flow measurement device
JP6136239B2 (en) Flow measuring device
JP5024272B2 (en) Air flow measurement device
US7051589B2 (en) Heating resistor flow rate measuring instrument
JP5477446B2 (en) Air flow measurement device
JP6507804B2 (en) Air flow measuring device
JP2007155533A (en) Apparatus for measuring air flow rate
WO2020202721A1 (en) Physical quantity measurement device
JP5218384B2 (en) Air flow measurement device
JP5852978B2 (en) Thermal flow meter

Legal Events

Date Code Title Description
A621 Written request for application examination

Free format text: JAPANESE INTERMEDIATE CODE: A621

Effective date: 20100426

A977 Report on retrieval

Free format text: JAPANESE INTERMEDIATE CODE: A971007

Effective date: 20120228

TRDD Decision of grant or rejection written
A01 Written decision to grant a patent or to grant a registration (utility model)

Free format text: JAPANESE INTERMEDIATE CODE: A01

Effective date: 20120306

A01 Written decision to grant a patent or to grant a registration (utility model)

Free format text: JAPANESE INTERMEDIATE CODE: A01

A61 First payment of annual fees (during grant procedure)

Free format text: JAPANESE INTERMEDIATE CODE: A61

Effective date: 20120319

FPAY Renewal fee payment (event date is renewal date of database)

Free format text: PAYMENT UNTIL: 20150413

Year of fee payment: 3

R151 Written notification of patent or utility model registration

Ref document number: 4968267

Country of ref document: JP

Free format text: JAPANESE INTERMEDIATE CODE: R151

FPAY Renewal fee payment (event date is renewal date of database)

Free format text: PAYMENT UNTIL: 20150413

Year of fee payment: 3

R250 Receipt of annual fees

Free format text: JAPANESE INTERMEDIATE CODE: R250

R250 Receipt of annual fees

Free format text: JAPANESE INTERMEDIATE CODE: R250

R250 Receipt of annual fees

Free format text: JAPANESE INTERMEDIATE CODE: R250

R250 Receipt of annual fees

Free format text: JAPANESE INTERMEDIATE CODE: R250

R250 Receipt of annual fees

Free format text: JAPANESE INTERMEDIATE CODE: R250

R250 Receipt of annual fees

Free format text: JAPANESE INTERMEDIATE CODE: R250

R250 Receipt of annual fees

Free format text: JAPANESE INTERMEDIATE CODE: R250

R250 Receipt of annual fees

Free format text: JAPANESE INTERMEDIATE CODE: R250

R250 Receipt of annual fees

Free format text: JAPANESE INTERMEDIATE CODE: R250

R250 Receipt of annual fees

Free format text: JAPANESE INTERMEDIATE CODE: R250