JPH089612Y2 - Intake air flow rate measuring device for internal combustion engine - Google Patents
Intake air flow rate measuring device for internal combustion engineInfo
- Publication number
- JPH089612Y2 JPH089612Y2 JP1987139325U JP13932587U JPH089612Y2 JP H089612 Y2 JPH089612 Y2 JP H089612Y2 JP 1987139325 U JP1987139325 U JP 1987139325U JP 13932587 U JP13932587 U JP 13932587U JP H089612 Y2 JPH089612 Y2 JP H089612Y2
- Authority
- JP
- Japan
- Prior art keywords
- passage
- flow rate
- throttle body
- bypass passage
- 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.)
- Expired - Lifetime
Links
Landscapes
- Measuring Volume Flow (AREA)
Description
【考案の詳細な説明】 〈産業上の利用分野〉 本考案は、内燃機関の吸入空気流量を計測する吸入空
気流量計測装置に関し、特に吸入空気流をバイパス通路
により分流してバイパス通路における空気流量を熱線式
流量計により計測する装置に関する。DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to an intake air flow rate measuring device for measuring an intake air flow rate of an internal combustion engine, and particularly to an intake air flow rate divided by a bypass passage to divide the intake air flow rate into the bypass passage. The present invention relates to a device for measuring a temperature with a hot wire type flow meter.
〈従来の技術〉 この種の吸入空気流量計測装置は、例えば第４図に示
すようなシングルポイントインジェクション方式の燃料
供給装置において使用されている。<Prior Art> This kind of intake air flow rate measuring device is used, for example, in a single point injection type fuel supply device as shown in FIG.
これについて説明すると、スロットルボディ１の主吸
気通路２には下流側にスロットル弁３が設けられ、上流
側には取付部４を介して燃料噴射弁５が設けられてい
る。この燃料噴射弁５は図示しない燃料ポンプから燃料
供給通路６を介して供給された燃料をスロットル弁３に
向けて噴射する。７はアイドル回転数制御用の補助空気
弁である。To explain this, a throttle valve 3 is provided on the downstream side of the main intake passage 2 of the throttle body 1, and a fuel injection valve 5 is provided on the upstream side via a mounting portion 4. The fuel injection valve 5 injects fuel supplied from a fuel pump (not shown) through the fuel supply passage 6 toward the throttle valve 3. Reference numeral 7 is an auxiliary air valve for idle speed control.
ここにおいて、スロットルボディ１の上流側端面に主
吸気通路２に対し隔壁８により隔てられたバイパス通路
９を開口させてある。そして、燃料噴射弁取付部４の外
周壁とこれを囲む主吸気通路２の内周壁とによってベン
チュリ10を形成し、そのスロート部10aにバイパス通路
９の出口を開口させて、スロート部10aに生じる負圧に
より、バイパス通路９への吸入空気流の分流を確保する
ようにしてある。そして、バイパス通路９の途中に熱線
式流量計11を介装し、バイパス通路９を流れる空気流量
を計測するようにしてある。Here, a bypass passage 9 separated from the main intake passage 2 by a partition wall 8 is opened at the upstream end surface of the throttle body 1. Then, the venturi 10 is formed by the outer peripheral wall of the fuel injection valve mounting portion 4 and the inner peripheral wall of the main intake passage 2 that surrounds the fuel injection valve mounting portion 4, and an outlet of the bypass passage 9 is opened in the throat portion 10a so that the venturi 10 is formed in the throat portion 10a. The negative pressure ensures that the intake air flow is divided into the bypass passage 9. A hot wire type flow meter 11 is provided in the middle of the bypass passage 9 to measure the flow rate of air flowing through the bypass passage 9.
従って、主吸気通路２を流れる空気流量とバイパス通
路９を流れる空気流量との分流比が一定である限り、こ
のバイパス通路９を流れる空気流量を熱線式流量計11に
より計測することで、全吸入空気流量が間接的に計測さ
れることになり、この計測された空気流量に基づき所定
混合比の混合気が得られるように燃料噴射弁５からの燃
料噴射量が制御される。Therefore, as long as the shunt ratio between the air flow rate flowing through the main intake passage 2 and the air flow rate passing through the bypass passage 9 is constant, the air flow rate flowing through the bypass passage 9 is measured by the hot-wire flow meter 11 so that the total intake The air flow rate is indirectly measured, and the fuel injection amount from the fuel injection valve 5 is controlled so that the air-fuel mixture having a predetermined mixing ratio is obtained based on the measured air flow rate.
〈考案が解決しようとする問題点〉 ところで、このようなバイパス式の吸入空気流量計測
装置において、スロットルボディ１の主吸気通路２及び
バイパス通路９の開口部の上流側が直管の場合には、低
流量から高流量まで、面積比に従って、分流比が一定と
なり、計測上何ら問題はない。<Problems to be Solved by the Invention> By the way, in such a bypass type intake air flow rate measuring device, when the upstream side of the opening of the main intake passage 2 of the throttle body 1 and the bypass passage 9 is a straight pipe, From low flow rate to high flow rate, the diversion ratio becomes constant according to the area ratio, and there is no problem in measurement.
しかし、第４図に示すようにスロットルボディ１の上
流側端面にエアクリーナ12を直接装着する場合、あるい
はエアクリーナからの吸気ダクトを直角に曲げて接続す
る場合など、エアクリーナ12側の吸気通路がスロットル
ボディ１の主吸気通路２及びバイパス通路９に対しほぼ
直角に接続される場合は、吸入空気がスロットルボディ
１の主吸気通路２及びバイパス通路９に対し斜めに流入
する（第５図及び第６図参照）。そして、この傾向は空
気流量が大きい程顕著となる。However, as shown in FIG. 4, when the air cleaner 12 is directly attached to the upstream end surface of the throttle body 1, or when the intake duct from the air cleaner is bent at a right angle to be connected, the intake passage on the air cleaner 12 side has a throttle body. When the intake air is connected to the main intake passage 2 and the bypass passage 9 at substantially right angles, the intake air obliquely flows into the main intake passage 2 and the bypass passage 9 of the throttle body 1 (FIGS. 5 and 6). reference). And this tendency becomes remarkable as the air flow rate increases.
このような斜め方向の流れに対しては、バイパス通路
９の有効面積が小さくなり、これにより高流量域で分流
比の低下により、第７図に示すように計測誤差を生じ、
また流量計出力が同一でも吸入空気流量が２値をとるよ
うな事態を生じる。With respect to such an oblique flow, the effective area of the bypass passage 9 becomes small, which causes a decrease in the diversion ratio in the high flow rate region, causing a measurement error as shown in FIG.
Further, even if the flowmeter output is the same, a situation occurs in which the intake air flow rate takes two values.
これを解決するため、実開昭60-35222号公報に示され
ているように、バイパス通路の入口にエアクリーナ側の
吸気通路における流れ方向と一致させた入口を有する案
内通路を設けるようにしたものもあるが、この案内通路
がスロットルボディの上流側端面より吐出することにな
るため、組立製造時においてアッセンブリ状態で取扱わ
れる際に破損等を生じ易く、また部品点数の増大により
コスト高となる不具合がある。In order to solve this, as disclosed in Japanese Utility Model Laid-Open No. 60-35222, a guide passage having an inlet matching the flow direction in the intake passage on the air cleaner side is provided at the inlet of the bypass passage. However, since this guide passage discharges from the upstream end surface of the throttle body, damage is likely to occur when it is handled in the assembled state during assembly and manufacturing, and the cost increases due to an increase in the number of parts. There is.
本考案は、このような不具合を生じることなく、分流
比を一定に保ち得て計測精度を向上させることができる
ようにすることを目的とする。An object of the present invention is to make it possible to keep the diversion ratio constant and improve the measurement accuracy without causing such a problem.
〈問題点を解決するための手段〉 このため、本考案は、主吸気通路とバイパス通路との
間の隔壁を、主吸気通路内に燃料噴射弁取付部によって
形成されるベンチュリの狭窄開始点であるスロットルボ
ディの上流側端面からベンチュリの狭窄開始点より下流
側位置まで切欠く構成としたものである。<Means for Solving Problems> Therefore, according to the present invention, the partition wall between the main intake passage and the bypass passage is formed at the start point of the constriction of the venturi formed by the fuel injection valve mounting portion in the main intake passage. It is configured such that a notch extends from an upstream end surface of a throttle body to a downstream position from a venturi constriction start point.
〈作用〉 上記の構成においては、斜め方向の流れに対してもバ
イパス通路の有効面積は大となり、高流量域での分流比
の低下が無く、計測誤差の発生はほとんど無くなる。<Operation> In the above-described configuration, the effective area of the bypass passage is large even in the diagonal flow, the diversion ratio is not reduced in the high flow rate region, and the measurement error is hardly generated.
〈実施例〉 以下に本考案の一実施例を第１図〜第３図に基づいて
説明する。但し、従来例と同一部分には同一符号を付し
て異なる部分についてのみ説明する。<Embodiment> An embodiment of the present invention will be described below with reference to FIGS. However, the same parts as those of the conventional example are denoted by the same reference numerals and only different parts will be described.
異なる部分は、主吸気通路２とバイパス通路９とを隔
てる隔壁８に、ベンチュリ10の狭窄開始点であるスロッ
トルボディ１の上流側端面から、それより下流側位置ま
で、切欠き部8aを形成してある。The different part is that a notch 8a is formed in the partition wall 8 that separates the main intake passage 2 and the bypass passage 9 from the upstream end surface of the throttle body 1 which is the start point of the constriction of the venturi 10 to the position downstream thereof. There is.
この切欠き部8aの巾方向の大きさ（Ｗ）は、隔壁８の
巾すなわち断面長円形のバイパス通路９の長径とほぼ同
じ大きさとし、高さ方向の大きさ（Ｈ）は、主吸気通路
２の径の約1/9以上とする。The size (W) of the notch portion 8a in the width direction is substantially the same as the width of the partition wall 8, that is, the major axis of the bypass passage 9 having an oval cross section, and the size (H) in the height direction is the main intake passage. It is about 1/9 or more of the diameter of 2.
かかる構成によれば、高流量域で吸入空気の流れが斜
めになると、第３図に示すようにバイパス通路９の有効
面積が大となり、高流量域での分流比の低下が無くな
り、計測誤差を生じることが無くなって、吸入空気流量
の変化に対し熱線式流量計11の出力が直線的に変化する
ようになる。According to this configuration, when the intake air flow becomes slanted in the high flow rate region, the effective area of the bypass passage 9 becomes large as shown in FIG. 3, and the diversion ratio in the high flow rate region does not decrease, resulting in a measurement error. Is eliminated, and the output of the hot wire type flow meter 11 changes linearly with respect to the change of the intake air flow rate.
また、本実施例では、エアクリーナ12のフィルターエ
レメント12aを円錐状に形成することによって吸入空気
流を早めに曲げてスムーズに分流するようにしている。Further, in the present embodiment, the filter element 12a of the air cleaner 12 is formed in a conical shape so that the intake air flow is bent earlier and smoothly divided.
〈考案の効果〉 以上説明したように本考案によれば、高流量域にてス
ロットルボディに対し吸入空気が斜めに流入する場合で
もバイパス通路への分流比をほぼ一定にすることがで
き、高流量域での分流比の低下が無く、計測精度を向上
できる。また、隔壁に切欠きを設ける構成であって、ス
ロットルボディから部品を突出させたり、スロットルボ
ディ自体を大型化しないので、取扱いの不便もなく、ま
たコスト高となることもない利点がある。<Effect of device> As described above, according to the present invention, even when intake air obliquely flows into the throttle body in the high flow rate range, the diversion ratio to the bypass passage can be made substantially constant, and a high flow rate can be achieved. There is no decrease in the diversion ratio in the flow rate range, and the measurement accuracy can be improved. Further, since the notch is provided in the partition wall, no parts are projected from the throttle body and the throttle body itself is not enlarged, which is advantageous in that there is no inconvenience in handling and no increase in cost.
第１図は本考案の一実施例を示す断面図、第２図は同上
実施例の概略平面図、第３図は同上実施例の概略断面
図、第４図は従来例を示す断面図、第５図は同上従来例
の概略平面図、第６図は同上従来例の概略断面図、第７
図は従来における熱線式流量計の出力特性図である。 １……スロットルボディ、２……主吸気通路、３……ス
ロットル弁、４……取付部、５……燃料噴射弁、８……
隔壁、8a……切欠き部、９……バイパス通路、10……ベ
ンチュリ、10a……スロート部、11……熱線式流量計、1
2……エアクリーナ、12a……フィルターエレメントFIG. 1 is a sectional view showing an embodiment of the present invention, FIG. 2 is a schematic plan view of the same embodiment, FIG. 3 is a schematic sectional view of the same embodiment, and FIG. 4 is a sectional view showing a conventional example. FIG. 5 is a schematic plan view of the above conventional example, and FIG. 6 is a schematic sectional view of the above conventional example.
The figure is an output characteristic diagram of a conventional hot wire type flow meter. 1 ... Throttle body, 2 ... Main intake passage, 3 ... Throttle valve, 4 ... Mounting part, 5 ... Fuel injection valve, 8 ...
Partition wall, 8a ... Notch portion, 9 ... Bypass passage, 10 ... Venturi, 10a ... Throat portion, 11 ... Hot wire type flow meter, 1
2 …… Air cleaner, 12a …… Filter element
Claims (1)
スロットル弁を設ける一方、上流側にその中心に位置さ
せた取付部により保持して燃料噴射弁を設けて、燃料噴
射弁取付部の外周壁とこれを囲む主吸気通路の内周壁と
によってスロットルボディの上流側端面から下流側に向
かって次第に狭窄するベンチュリを形成し、スロットル
ボディの上流側端面に主吸気通路に対し隔壁により隔て
られて吸入空気を分流するバイパス通路を開口させ、こ
のバイパス通路の出口を前記ベンチュリのスロート部に
開口させ、このバイパス通路の途中に熱線式流量計を介
装してなる内燃機関の吸入空気流量計測装置であって、 スロットルボディの上流側にてエアクリーナ側の吸気通
路がスロットルボディの主空気通路及びバイパス通路に
対してほぼ直角に接続されるものにおいて、 主吸気通路とバイパス通路との間の隔壁を前記ベンチュ
リの狭窄開始点であるスロットルボディの上流側端面か
ら前記ベンチュリの狭窄開始点より下流側位置まで切欠
いたことを特徴とする内燃機関の吸入空気流量計測装
置。1. A throttle valve is provided on the downstream side of a main intake passage of a throttle body, and a fuel injection valve is provided on the upstream side by a mounting portion located at the center thereof. The wall and the inner peripheral wall of the main intake passage surrounding the wall form a venturi that gradually narrows from the upstream end surface of the throttle body toward the downstream side, and is separated from the main intake passage by a partition wall on the upstream end surface of the throttle body. An intake air flow rate measuring device for an internal combustion engine, in which a bypass passage for dividing intake air is opened, an outlet of the bypass passage is opened in a throat portion of the venturi, and a hot wire type flow meter is interposed in the middle of the bypass passage. In addition, the intake passage on the air cleaner side on the upstream side of the throttle body is substantially perpendicular to the main air passage and the bypass passage of the throttle body. In the connection, the partition wall between the main intake passage and the bypass passage is notched from the upstream end surface of the throttle body, which is the start point of the constriction of the venturi, to a position downstream from the start point of the constriction of the venturi. Intake air flow rate measuring device for internal combustion engine.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1987139325U JPH089612Y2 (en) | 1987-09-14 | 1987-09-14 | Intake air flow rate measuring device for internal combustion engine |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1987139325U JPH089612Y2 (en) | 1987-09-14 | 1987-09-14 | Intake air flow rate measuring device for internal combustion engine |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS6444421U JPS6444421U (en) | 1989-03-16 |
| JPH089612Y2 true JPH089612Y2 (en) | 1996-03-21 |
Family
ID=31402475
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP1987139325U Expired - Lifetime JPH089612Y2 (en) | 1987-09-14 | 1987-09-14 | Intake air flow rate measuring device for internal combustion engine |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH089612Y2 (en) |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5676012A (en) * | 1979-11-27 | 1981-06-23 | Hitachi Ltd | Measuring device of suction air quantity |
| JPS59142164A (en) * | 1983-02-02 | 1984-08-15 | Matsushita Electric Ind Co Ltd | Dot printer |
-
1987
- 1987-09-14 JP JP1987139325U patent/JPH089612Y2/en not_active Expired - Lifetime
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5676012A (en) * | 1979-11-27 | 1981-06-23 | Hitachi Ltd | Measuring device of suction air quantity |
| JPS59142164A (en) * | 1983-02-02 | 1984-08-15 | Matsushita Electric Ind Co Ltd | Dot printer |
Also Published As
| Publication number | Publication date |
|---|---|
| JPS6444421U (en) | 1989-03-16 |
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