JPH0524189Y2 - - Google Patents
Info
- Publication number
- JPH0524189Y2 JPH0524189Y2 JP1987071776U JP7177687U JPH0524189Y2 JP H0524189 Y2 JPH0524189 Y2 JP H0524189Y2 JP 1987071776 U JP1987071776 U JP 1987071776U JP 7177687 U JP7177687 U JP 7177687U JP H0524189 Y2 JPH0524189 Y2 JP H0524189Y2
- Authority
- JP
- Japan
- Prior art keywords
- hot film
- film element
- pair
- intake air
- leads
- 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
- 239000000428 dust Substances 0.000 claims description 34
- 230000002265 prevention Effects 0.000 claims description 20
- 238000011144 upstream manufacturing Methods 0.000 claims description 10
- 238000013459 approach Methods 0.000 claims description 4
- 238000002485 combustion reaction Methods 0.000 claims description 3
- 239000011248 coating agent Substances 0.000 claims description 2
- 238000000576 coating method Methods 0.000 claims description 2
- 239000002184 metal Substances 0.000 claims 1
- 230000007423 decrease Effects 0.000 description 4
- 230000017525 heat dissipation Effects 0.000 description 4
- BASFCYQUMIYNBI-UHFFFAOYSA-N platinum Chemical compound [Pt] BASFCYQUMIYNBI-UHFFFAOYSA-N 0.000 description 4
- 238000001514 detection method Methods 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 238000005259 measurement Methods 0.000 description 2
- 229910052697 platinum Inorganic materials 0.000 description 2
- 238000005219 brazing Methods 0.000 description 1
- 239000012141 concentrate Substances 0.000 description 1
- 238000001816 cooling Methods 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 239000011521 glass Substances 0.000 description 1
- 238000009434 installation Methods 0.000 description 1
- 230000000087 stabilizing effect Effects 0.000 description 1
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測定する
ホツトフイルム式流量計に関し、特にホツトフイ
ルム素子のリードに塵が付着することを防止する
ための技術に関する。[Detailed description of the invention] <Industrial field of application> The present invention relates to a hot film flowmeter for measuring the intake air flow rate of an internal combustion engine, and is particularly designed to prevent dust from adhering to the leads of the hot film element. Regarding technology.
〈従来の技術〉
この種のホツトフイルム式流量計としては第２
図〜第４図に示すようなものがある（実開昭61−
108930号公報等参照）。<Prior art> This is the second hot film flowmeter of this type.
There is something like the one shown in Fig.
(See Publication No. 108930, etc.)
第２図及び第３図において、ホツトフイルム素
子１は円筒体の表面にホツトフイルムとして機能
する白金が被膜され、その上からガラスコーテイ
ングしてあり、その両端からそれぞれリード１
ａ，１ｂを突き出した構成となつており、該リー
ド１ａ，１ｂを機関吸気通路に装着されたプラグ
２の開口部２ａの底壁に立設された一対の端子３
ａ，３ｂにロー付けして接続される。プラグ２の
開口部２ａには、この他温度補償抵抗４が両端を
開口部２ａに立設された一対の端子５ａ，５ｂに
把持して接続され、更にプラグ２の一端部にはコ
イル状の基準抵抗６が巻回されている。 In FIGS. 2 and 3, a hot film element 1 has a cylindrical body whose surface is coated with platinum that functions as a hot film, and a glass coating is applied on top of the platinum, and leads 1 are formed from each end of the cylindrical body.
The leads 1a and 1b are connected to a pair of terminals 3 erected on the bottom wall of the opening 2a of the plug 2 installed in the engine intake passage.
Connected to a and 3b by brazing. In addition, a temperature compensating resistor 4 is connected to the opening 2a of the plug 2 by gripping both ends to a pair of terminals 5a and 5b set up in the opening 2a, and furthermore, a coil-shaped resistor 4 is connected to the opening 2a of the plug 2. A reference resistor 6 is wound.
そして、第４図に示すようにこれらホツトフイ
ルム素子１、温度補償抵抗４、基準抵抗６と吸気
通路外部に設けられる２つの固定抵抗７，８とに
よりブリツジ回路が構成されている。 As shown in FIG. 4, a bridge circuit is constituted by the hot film element 1, temperature compensation resistor 4, reference resistor 6, and two fixed resistors 7 and 8 provided outside the intake passage.
このブリツジ回路のホツトフイルム素子１及び
基準抵抗６が直列に接続されている側の分圧点ａ
の電位US（基準抵抗６の端子電圧）と、温度補償
抵抗４、固定抵抗７，８が直列に接続されている
側の分圧点ｂの電位（固定抵抗８の端子電圧）と
が差動増幅器９に入力さるうようになつており、
この差動増幅器９とトランジスタ１０，１１とに
よりブリツジ回路への供給電流が補正される。 The voltage dividing point a on the side where the hot film element 1 and the reference resistor 6 of this bridge circuit are connected in series.
There is a difference between the potential US (terminal voltage of the reference resistor 6) and the potential at the voltage dividing point b (terminal voltage of the fixed resistor 8) on the side where the temperature compensation resistor 4 and fixed resistors 7 and 8 are connected in series. It is designed to be input to amplifier 9,
The differential amplifier 9 and transistors 10 and 11 correct the current supplied to the bridge circuit.
従つて、ブリツジ回路が平衡している状態にお
いて、機関の吸入空気流量が例えば増大すると、
ホツトフイルム素子１がこの吸気流によつてより
冷却されてその抵抗値が減少し、ブリツジ回路が
非平衡となり、基準抵抗６の端子電圧USが増大
して、差動増幅器９の出力が増大する。これによ
り、トランジスタ１０，１１によつて制御される
ブリツジ回路への供給電流が増大し、ホツトフイ
ルム素子１が加熱されてその抵抗値が増大してブ
リツジ回路の平衡条件が回復される。 Therefore, if the intake air flow rate of the engine increases, for example, when the bridge circuit is in equilibrium,
The hot film element 1 is further cooled by this intake air flow, its resistance value decreases, the bridge circuit becomes unbalanced, the terminal voltage US of the reference resistor 6 increases, and the output of the differential amplifier 9 increases. . This increases the current supplied to the bridge circuit controlled by transistors 10 and 11, heats the hot film element 1, increases its resistance value, and restores the equilibrium condition of the bridge circuit.
ここで、吸入空気温度が例えば低下すると、ホ
ツトフイルム素子１が冷却されてその抵抗値が減
少するが、ホツトフイルム素子１と同一雰囲気に
ある温度補償抵抗４も同時に冷却され、その抵抗
値が減少するから、ブリツジ回路へ供給される電
流値が吸入空気温度の変化により変化するのが抑
制される。 Here, when the intake air temperature decreases, for example, the hot film element 1 is cooled and its resistance value decreases, but the temperature compensation resistor 4, which is in the same atmosphere as the hot film element 1, is also cooled at the same time and its resistance value decreases. Therefore, changes in the current value supplied to the bridge circuit due to changes in intake air temperature are suppressed.
即ち、吸入空気流量とブリツジ回路への供給電
流とが吸入空気温度に無関係に対応することにな
り、例えば、基準抵抗６の端子電圧USを検出す
ることにより機関の吸入空気流量が測定されるも
のである。 In other words, the intake air flow rate and the current supplied to the bridge circuit correspond to each other regardless of the intake air temperature.For example, the intake air flow rate of the engine is measured by detecting the terminal voltage US of the reference resistor 6. It is.
〈考案が解決しようとする問題点〉
ところで、かかるホツトフイルム式流量計にあ
つては、ホツトフイルム素子１やリード１ａ，１
ｂの吸気上流側表面に吸気中の塵が付着し、また
エアクリーナに含まれているオイルやブローバイ
ガスが媒体となつてこの塵の付着が加速されるこ
ともある。<Problems to be solved by the invention> By the way, in such a hot film type flowmeter, the hot film element 1 and the leads 1a, 1
Dust in the intake air adheres to the upstream surface of the intake air, and the adhesion of this dust may be accelerated by the oil or blow-by gas contained in the air cleaner serving as a medium.
ホツトフイルム素子１の表面温度は、白金被膜
への通電によつてオイル等が燃え易い温度（200
〜300℃）にまで高められているため、塵付着量
の増大を抑制できるが、リード１ａ，１ｂの表面
温度は低い（100〜150℃）ため、オイルが付着し
て塵が比較的短期間に付着堆積する。このように
して塵がリード１ａ，１ｂに付着堆積すると、ホ
ツトフイルム素子１の放熱特性が変化する（付着
堆積した塵が吸気流によるリード１ａ，１ｂの冷
却を妨げる）ため、ホツトフイルム素子の放熱特
性がこれに影響されて吸入空気流量の測定精度が
悪化してしまうという問題があつた。 The surface temperature of the hot film element 1 is the temperature at which oil, etc. is easily flammable (200
However, since the surface temperature of leads 1a and 1b is low (100 to 150°C), the oil adheres and the dust remains for a relatively short period of time. It is deposited on the surface. When dust adheres and accumulates on the leads 1a and 1b in this way, the heat dissipation characteristics of the hot film element 1 change (the accumulated dust prevents the cooling of the leads 1a and 1b by the intake air flow). There was a problem in that the characteristics were affected by this and the measurement accuracy of the intake air flow rate deteriorated.
本考案は上記問題点に鑑みなされたものであ
り、ホツトフイルム素子のリードに塵が付着堆積
することを防止して素子の放熱特性が変化するこ
とを回避できるホツトフイルム式流量計を提供す
ることを目的とする。 The present invention has been devised in view of the above-mentioned problems, and an object of the present invention is to provide a hot film type flowmeter that can prevent dust from adhering and accumulating on the leads of a hot film element, thereby avoiding changes in the heat dissipation characteristics of the element. With the goal.
〈問題点を解決するための手段〉
そのため本考案では、ホツトフイルム素子の軸
方向に対して直交する方向に延設され、一対のリ
ードを吸気通路上流側に近接してそれぞれ覆う一
対の塵付着防止部材を設けると共に、該一対の塵
付着防止部材の相対面を、上流側から下流側に向
けて徐々に近接する円弧状に形成した構成とす
る。<Means for Solving the Problems> Therefore, in the present invention, a pair of dust-adhering leads are installed in a direction perpendicular to the axial direction of the hot film element and cover a pair of leads close to the upstream side of the intake passage. A prevention member is provided, and the opposing surfaces of the pair of dust adhesion prevention members are formed into arc shapes that gradually approach each other from the upstream side to the downstream side.
〈作用〉
かかる構成によると、ホツトフイルム素子のリ
ードは、塵付着防止部材によつて吸気流の陰に位
置することになるため、オイルや塵はこの塵付着
防止部に付着し、リードへの付着を効果的に防止
できる。また、前記一対の塵付着防止部材が、ホ
ツトフイルム素子の軸方向に対して直交する方向
に延設され、かつ、その相対面が上流側から下流
側に向けて徐々に近接する円弧状に形成されてい
るから、この一対の塵付着防止部材によつて素子
部に吸気流が集められるようになつている。<Function> According to this configuration, the leads of the hot film element are positioned in the shadow of the intake air flow by the dust adhesion prevention member, so oil and dust adhere to this dust adhesion prevention member and are prevented from reaching the leads. Adhesion can be effectively prevented. Further, the pair of dust adhesion prevention members extend in a direction perpendicular to the axial direction of the hot film element, and the opposing surfaces thereof are formed in an arc shape that gradually approaches each other from the upstream side to the downstream side. Therefore, the pair of dust adhesion prevention members allows the intake air flow to be collected at the element portion.
〈実施例〉
以下に本考案の一実施例を図面に基づいて説明
する。尚、第２図及び第３図に示した従来例と同
一要素には同一符号を付してある。<Example> An example of the present invention will be described below based on the drawings. Incidentally, the same elements as those in the conventional example shown in FIGS. 2 and 3 are given the same reference numerals.
一実施例を示す第１図において、ホツトフイル
ム素子１は、その両端から突出させた一対のリー
ド１ａ，１ｂを、プラグ２の開口部２ａ底壁に立
設された端子３ａ，３ｂにロー付けにより接続し
て取り付けられることは従来と同様である。ここ
で、本考案に係る構成として、プラグ２が装着さ
れる吸気通路の内周壁の一側から他側へ掛け渡す
ようにして一対の塵付着防止部材２０ａ，２０ｂ
を吸気通路壁と一体に形成してあり、この塵付着
防止部材２０ａ，２０ｂはリード１ａ，１ｂを吸
気通路上流側に近接して覆うようにしてある。ま
た、上記塵付着防止部材２０ａ，２０ｂは、吸気
流れの障害とならず、かつホツトフイルム素子１
に対して吸気を集めるように、相対面が上流側か
ら下流側に向けて徐々に近接するようにそれぞれ
円弧状に形成してある。 In FIG. 1 showing one embodiment, a hot film element 1 has a pair of leads 1a, 1b protruding from both ends thereof, which are brazed to terminals 3a, 3b erected on the bottom wall of an opening 2a of a plug 2. The connection and installation are the same as in the conventional case. Here, as a configuration according to the present invention, a pair of dust adhesion prevention members 20a and 20b are provided so as to span from one side to the other side of the inner circumferential wall of the intake passage where the plug 2 is attached.
are formed integrally with the intake passage wall, and the dust adhesion prevention members 20a, 20b cover the leads 1a, 1b close to the upstream side of the intake passage. In addition, the dust adhesion prevention members 20a and 20b do not obstruct the intake air flow and prevent the hot film element 1
The opposing surfaces are each formed in an arcuate shape so as to gradually approach each other from the upstream side to the downstream side so as to collect intake air.
かかる構成とすれば、リード１ａ，１ｂは塵付
着防止部材２０ａ，２０ｂによつて吸気流の陰と
なり、吸気中に含まれるオイルや塵は塵付着防止
部材２０ａ，２０ｂの上流側端縁に付着すること
によつてリード１ａ，１ｂへの付着を防止でき
る。また、本実施例のように塵付着防止部材２０
ａ，２０ｂを吸気上流側に向けて先細りとなる形
状にしてあれば、塵付着防止部材２０ａ，２０ｂ
に対する塵の付着も極力抑えることができる。 With this configuration, the leads 1a and 1b are shaded from the intake air flow by the dust adhesion prevention members 20a and 20b, and oil and dust contained in the intake air adhere to the upstream edges of the dust adhesion prevention members 20a and 20b. By doing so, adhesion to the leads 1a and 1b can be prevented. In addition, as in this embodiment, the dust adhesion prevention member 20
If a and 20b are tapered toward the intake upstream side, the dust adhesion prevention members 20a and 20b
It is also possible to suppress the adhesion of dust to the surface as much as possible.
また、端子３ａ，３ｂは、従来と同様にその端
面が吸気流と平行になるような板状であるため、
その端縁に塵が付着することはあるものの、リー
ド１ａ，１ｂ（ホツトフイルム素子１）の放熱特
性に影響を与えるほど塵が付着堆積することはな
い。また、塵付着防止部材２０ａ，２０ｂが、素
子１に対して吸気を集中させるような形状に形成
されているから、吸気流の乱れの影響を抑止し
て、流量検出精度を高めることができる。 In addition, since the terminals 3a and 3b are plate-shaped with their end surfaces parallel to the intake air flow, as in the conventional case,
Although dust may adhere to the edges, the dust does not accumulate to the extent that it affects the heat dissipation characteristics of the leads 1a, 1b (hot film element 1). Further, since the dust adhesion prevention members 20a and 20b are formed in a shape that concentrates the intake air on the element 1, it is possible to suppress the influence of turbulence in the intake air flow and improve the accuracy of flow rate detection.
更に、塵付着防止部材２０ａ，２０ｂは吸気通
路壁と一体に形成してあるため、部品点数の増加
や組み立て工数の増加を招くことがなく、簡便な
構成でリード１ａ，１ｂへの塵付着を防止でき
る。 Furthermore, since the dust adhesion prevention members 20a and 20b are formed integrally with the intake passage wall, there is no increase in the number of parts or assembly man-hours, and a simple configuration prevents dust from adhering to the leads 1a and 1b. It can be prevented.
〈考案の効果〉
以上説明したように本考案によると、吸気通路
壁と一体に設けた塵付着防止部材によつてホツト
フイルム素子のリードに塵が付着することを防止
でき、塵の付着堆積によるホツトフイルム素子の
放熱特性変化を回避して、吸入空気流量の測定精
度が長期に亘つて安定化するという効果がある。
また、一対の塵付着防止部材によつて素子部に吸
気流を集中させることがでるから、検出精度を向
上させることができる。<Effects of the invention> As explained above, according to the invention, the dust adhesion prevention member provided integrally with the intake passage wall can prevent dust from adhering to the leads of the hot film element, and prevent dust from accumulating. This has the effect of avoiding changes in the heat dissipation characteristics of the hot film element and stabilizing the measurement accuracy of the intake air flow rate over a long period of time.
Further, since the pair of dust adhesion prevention members allows the intake air flow to be concentrated on the element portion, detection accuracy can be improved.
第１図は本考案の一実施例を示すホツトフイル
ム素子の取り付け部斜視図、第２図は従来のホツ
トフイルム式流量計の概略構成を示す正面図、第
３図は従来のホツトフイルム素子の取り付け部を
示す斜視図、第４図はホツトフイルム式流量計の
回路図である。
１……ホツトフイルム素子、１ａ，１ｂ……リ
ード、３ａ，３ｂ……端子、２０ａ，２０ｂ……
塵付着防止部材。
Fig. 1 is a perspective view of a mounting portion of a hot film element showing an embodiment of the present invention, Fig. 2 is a front view showing a schematic configuration of a conventional hot film flow meter, and Fig. 3 is a perspective view of a conventional hot film element. FIG. 4 is a perspective view showing the mounting portion and a circuit diagram of the hot film flowmeter. 1... Hot film element, 1a, 1b... Lead, 3a, 3b... Terminal, 20a, 20b...
Dust adhesion prevention member.
Claims (1)
ードを突出させてなるホツトフイルム素子を、機
関の吸気通路に装着されたプラグの開口部に立設
された一対の端子に前記一対のリードを接続して
取り付け、該ホツトフイルム素子と抵抗とにより
形成したブリツジ回路に供給する電流を、機関の
吸入空気流量に応じたホツトフイルム素子の抵抗
値変化に伴つて制御することにより、機関の吸入
空気流量を測定するようにした内燃機関用ホツト
フイルム式流量計において、前記ホツトフイルム
素子の軸方向に対して直交する方向に延設され、
前記一対のリードを吸気通路上流側に近接してそ
れぞれ覆う一対の塵付着防止部材を設けると共
に、該一対の塵付着防止部材の相対面を、上流側
から下流側に向けて徐々に近接する円弧状に形成
したことを特徴とする内燃機関用ホツトフイルム
式流量計。 A hot film element having a metal coating applied to the surface of a cylindrical body and having leads protruding from both ends is connected to a pair of terminals set upright at the opening of a plug installed in the intake passage of an engine. By connecting and installing the hot film element and controlling the current supplied to the bridge circuit formed by the hot film element and the resistor as the resistance value of the hot film element changes depending on the flow rate of the engine's intake air, the intake air of the engine can be controlled. In a hot film flow meter for an internal combustion engine configured to measure a flow rate, the hot film element extends in a direction perpendicular to the axial direction of the hot film element,
A pair of dust adhesion prevention members are provided that respectively cover the pair of leads close to the upstream side of the intake passage, and the opposing surfaces of the pair of dust adhesion prevention members are arranged in circles that gradually approach each other from the upstream side toward the downstream side. A hot film flowmeter for internal combustion engines characterized by an arcuate shape.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1987071776U JPH0524189Y2 (en) | 1987-05-15 | 1987-05-15 |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1987071776U JPH0524189Y2 (en) | 1987-05-15 | 1987-05-15 |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS63181923U JPS63181923U (en) | 1988-11-24 |
| JPH0524189Y2 true JPH0524189Y2 (en) | 1993-06-21 |
Family
ID=30914639
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP1987071776U Expired - Lifetime JPH0524189Y2 (en) | 1987-05-15 | 1987-05-15 |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH0524189Y2 (en) |
Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS59190624A (en) * | 1983-04-13 | 1984-10-29 | Hitachi Ltd | Intake air flowmeter |
-
1987
- 1987-05-15 JP JP1987071776U patent/JPH0524189Y2/ja not_active Expired - Lifetime
Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS59190624A (en) * | 1983-04-13 | 1984-10-29 | Hitachi Ltd | Intake air flowmeter |
Also Published As
| Publication number | Publication date |
|---|---|
| JPS63181923U (en) | 1988-11-24 |
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