JPH10220300A - Intake device for internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To form a porous member in a small size, increase an absorbing fuel rate, and prevent absorbing fuel rate from flowing out by rapidly accelerating operation in one breath by forming the inner diameter of the porous member smaller than that of an intake passage pipe. SOLUTION: A large diameter cylindrical part 37 is formed on an inlet end part of an intake passage pipe 5 provided with an intake passage 34, and a porous member 36 is inserted thereto, which is held between carburetor main body 15 and the cylindrical part 37. A circulating hole 36a having an inner diameter smaller than that of an intake passage 34 is arranged on the porous member 36. Since fuel bypassing the porous member 36 becomes fine fuel grains, gasification of fuel is facilitated. Since the temperature of the intake passage pipe 5 is reduced by gasifying fuel, temperature raising of a carburetor 6 is suppressed. If an engine is inclined during idling operation, fuel absorbed on the porous member 36 not flow into an engine in one breath, and thereby, engine stop is not caused so as to provide stable rotation.

Description

【発明の詳細な説明】DETAILED DESCRIPTION OF THE INVENTION

【０００１】[0001]

【発明の属する技術分野】本発明は携帯作業機に搭載さ
れる内燃機関の吸気装置、特に膜型気化器から機関の吸
気ポートに至る吸気路に配設され、機関の姿勢変化で機
関へ供給される燃料量が異常に急増するのを抑えるよう
にしたり、急加速運転で機関へ供給される燃料量が薄す
ぎるのを抑えるようにした内燃機関の吸気装置に関し、
特に４行程機関において効果が大なる内燃機関の吸気装
置に関するものである。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an intake device for an internal combustion engine mounted on a portable work machine, and more particularly, to an intake path from a membrane carburetor to an intake port of the engine. In regard to an intake device of an internal combustion engine, which suppresses an abnormally rapid increase in the amount of fuel to be supplied, or suppresses an excessively small amount of fuel supplied to the engine in sudden acceleration operation.
More particularly, the present invention relates to an intake device for an internal combustion engine, which has a great effect in a four-stroke engine.

【０００２】[0002]

【従来の技術】動力鋸、刈払機などの携帯作業機の機関
には、小型、軽量、高出力で、全姿勢での運転が可能な
ものが要求される。このため、一般には膜型気化器を備
えた空冷２行程機関が採用されているが、近年は排ガス
対策のために４行程機関も利用されるようになつた。機
関の運転中は周囲温度が非常に高くなるので、気化器の
燃料の蒸発を抑えるために、気化器と機関の吸気ポート
との間には、金属よりも断熱性に優れた合成樹脂製の吸
気路管が接続される。2. Description of the Related Art Engines for portable working machines such as power saws and brush cutters are required to be small, light, high-output, and capable of operating in all postures. For this reason, an air-cooled two-stroke engine equipped with a film-type vaporizer is generally employed, but in recent years, a four-stroke engine has also been used for exhaust gas control. During operation of the engine, the ambient temperature becomes very high.In order to suppress evaporation of the fuel in the carburetor, a synthetic resin made of synthetic resin, which has better heat insulation properties than metal, is placed between the carburetor and the intake port of the engine. An intake pipe is connected.

【０００３】ところで、従来の機関の吸気装置では機関
の冷間始動時やアイドル運転時、燃料の霧化ないし気化
が十分でないため、気化器の吸気路へ吸引された燃料
が、液状のまま吸気路管の内部に溜つてしまうことがあ
る。吸気路管の内部に溜つた多量の燃料が、携帯作業機
の姿勢変化に伴つて機関へ急激に供給されると、混合気
が濃すぎて機関が停止することがある。In the conventional intake system for an engine, when the engine is cold started or idling, the fuel is not sufficiently atomized or vaporized. Therefore, the fuel sucked into the intake passage of the carburetor is in a liquid state. It may accumulate inside the duct. If a large amount of fuel accumulated inside the intake pipe is rapidly supplied to the engine due to a change in the posture of the portable work machine, the mixture may be too rich and the engine may stop.

【０００４】２行程機関の低速運転特性を改善するため
に、実公昭53-53011号公報に開示されるように、吸気路
に区画された低速吸気路を排気または冷却水により加熱
し、燃料の気化を促すものが知られているが、軽負荷で
運転されることがあまりなく、作業中は全負荷で運転さ
れる携帯作業機の機関では、運転姿勢の変化に伴う燃料
の流れの停滞や乱れを改善することが難しい。特に、４
行程機関では混合気が直接燃焼室へ吸入されるので、こ
の傾向が強い。[0004] In order to improve the low-speed operation characteristics of a two-stroke engine, as disclosed in Japanese Utility Model Publication No. 53-53011, a low-speed intake passage defined by an intake passage is heated by exhaust or cooling water to reduce fuel consumption. Although it is known that it promotes vaporization, it is not often operated at light load, and in a portable work machine engine operated at full load during work, stagnation of fuel flow due to change in driving posture and It is difficult to improve turbulence. In particular, 4
This tendency is strong in a stroke engine because the air-fuel mixture is directly sucked into the combustion chamber.

【０００５】図４に示すように、実開昭59-28660号公報
に開示される内燃機関の吸気装置では、（ａ）多孔質部
材５６の容積を増大しにくいので、極く短い時間しか効
果を維持できない。多孔質部材５６の容積を増大するた
めには、多孔質部材５６の外径を大きくしなければなら
ず、吸気路管５が大きくなる。（ｂ）吸気路に直交して
開口する表面がなく、速やかに予剰燃料を吸収すること
ができない。……などの理由から、上述の構成では十分
に効果を発揮できない。As shown in FIG. 4, in the intake system of an internal combustion engine disclosed in Japanese Utility Model Laid-Open Publication No. 59-28660, (a) it is difficult to increase the volume of the porous member 56, so that only a very short time is effective. Cannot be maintained. In order to increase the volume of the porous member 56, the outer diameter of the porous member 56 must be increased, and the size of the intake pipe 5 increases. (B) There is no surface that opens perpendicular to the intake path, and it is not possible to quickly absorb the surplus fuel. For the reasons such as..., The above-described configuration cannot provide a sufficient effect.

【０００６】実開昭59-28660号公報の第４図に開示され
る内燃機関の吸気装置では、多孔質部材が吸気路管の内
面の全面に亘つて設けられているので吸着燃料量が増加
し、アイドル運転時の傾斜性は向上するが、急加速運転
で吸着燃料が多孔質部材の表面から一気に機関へ吸入さ
れ、却つて加速性が悪くなり、排ガスが汚くなるなどの
問題がある。また、個々の機関に最適な多孔質部材の表
面積を決めなければならず、多孔質部材の表面積の設定
が難しい。In the intake device for an internal combustion engine disclosed in FIG. 4 of Japanese Utility Model Laid-Open Publication No. 59-28660, the amount of adsorbed fuel increases because the porous member is provided over the entire inner surface of the intake pipe. However, the inclination during the idling operation is improved, but there is a problem that the adsorbed fuel is sucked into the engine from the surface of the porous member at once in the rapid acceleration operation, and the acceleration is deteriorated and the exhaust gas becomes dirty. In addition, it is necessary to determine the optimum surface area of the porous member for each engine, and it is difficult to set the surface area of the porous member.

【０００７】[0007]

【発明が解決しようとする課題】本発明の課題は上述の
問題に鑑み、多孔質部材が小形で吸着燃料量が多く、急
加速運転などで吸着燃料が一気に流出することがない、
内燃機関の吸気装置を提供することにある。SUMMARY OF THE INVENTION In view of the above-mentioned problems, the object of the present invention is to reduce the size of the porous member and the amount of adsorbed fuel so that the adsorbed fuel does not flow out at once in a sudden acceleration operation.
An intake device for an internal combustion engine is provided.

【０００８】[0008]

【課題を解決するための手段】上記課題を解決するため
に、本発明の構成は気化器の吸気路を機関の吸気ポート
へ接続する吸気路管の内周壁に多孔質部材を配設したも
のにおいて、前記多孔質部材の内径を吸気路管の内径よ
りも小さくしたものである。In order to solve the above-mentioned problems, a configuration of the present invention is such that a porous member is disposed on an inner peripheral wall of an intake passage pipe connecting an intake passage of a carburetor to an intake port of an engine. In the above, the inner diameter of the porous member is smaller than the inner diameter of the intake pipe.

【０００９】[0009]

【発明の実施の形態】本発明では環状の多孔質部材が吸
気路管の内部へ突出して設けられるので、多孔質部材の
吸着表面積が広くなり、燃料が吸着されやすく、多孔質
部材を経由した燃料は気化しやすくなる。機関の始動時
は多孔質部材の吸着燃料が一気に流出し、濃い混合気が
機関へ供給されるということはないので、始動不良を防
ぐことができる。また、多孔質部材に吸着された燃料が
徐々に機関へ吸引されるので、初爆時間が延び、暖気運
転も容易になる。BEST MODE FOR CARRYING OUT THE INVENTION In the present invention, since an annular porous member is provided so as to protrude into the intake passage pipe, the adsorption surface area of the porous member is widened, fuel is easily adsorbed, and the fuel passes through the porous member. The fuel becomes easier to vaporize. At the time of starting the engine, the adsorbed fuel of the porous member flows out at a stretch, and a rich mixture is not supplied to the engine, so that poor starting can be prevented. Further, since the fuel adsorbed by the porous member is gradually sucked into the engine, the initial explosion time is extended and the warm-up operation is facilitated.

【００１０】アイドル運転では吸気路管を流れる吸気の
流速が遅いので、多孔質部材の突出部分に燃料が吸着さ
れやすい。多孔質部材を通る燃料は極く細かい燃料粒に
なるので燃料の気化が容易になり、また、燃料の気化は
吸気路管の温度を下げるので、気化器の温度上昇が抑え
られ、機関の安定した回転が得られる。In idling operation, the flow rate of the intake air flowing through the intake passage pipe is low, so that the fuel is easily adsorbed on the protruding portion of the porous member. The fuel passing through the porous member becomes extremely fine fuel particles, which facilitates the vaporization of the fuel.Furthermore, the vaporization of the fuel lowers the temperature of the intake pipe, thereby suppressing the temperature rise of the vaporizer and stabilizing the engine. Rotation is obtained.

【００１１】アイドル運転で機関が傾斜しても、多孔質
部材に吸着された燃料が一気に機関へ流れ込むことはな
いので、機関停止は起こらず、安定した回転が得られ
る。[0011] Even if the engine is tilted during idling, the fuel adsorbed by the porous member does not flow into the engine at a stretch, so that the engine does not stop and stable rotation can be obtained.

【００１２】[0012]

【実施例】図１に示すように、機関の吸気ポート４に
は、断熱性の吸気路管（インシユレータ）５を介して膜
型気化器６が接続される。気化器６はベンチユリ吸気路
１６を有する本体１５の上部に燃料ポンプＡを構成され
る一方、下部に燃料定量機構Ｂを構成される。すなわ
ち、燃料ポンプＡは本体１５の上端部に膜１０を挟んで
カバー１４を結合し、膜１０の下側にポンプ室１２を区
画する。燃料ポンプＡは２行程機関ではクランク室５５
の脈動圧を、４行程機関では吸気管負圧を、入口８から
膜１０の上側の室９へ導入することにより、図示してな
い燃料槽の燃料を入口４０、逆止弁７を経てポンプ室１
２へ吸引し、逆止弁１３を経て通路１７へ吐き出す。DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS As shown in FIG. 1, a membrane carburetor 6 is connected to an intake port 4 of an engine via an adiabatic intake pipe (insulator) 5. In the carburetor 6, a fuel pump A is formed at an upper portion of a main body 15 having a bench lily intake passage 16, and a fuel metering mechanism B is formed at a lower portion. That is, in the fuel pump A, the cover 14 is connected to the upper end of the main body 15 with the membrane 10 interposed therebetween, and the pump chamber 12 is partitioned below the membrane 10. Fuel pump A is a crankcase 55 for a two-stroke engine.
Of the fuel tank (not shown) through the inlet 40 and the non-return valve 7 by introducing the pulsating pressure of the fuel into the chamber 9 above the membrane 10 from the inlet 8 in the four-stroke engine. Room 1
2 and is discharged through the check valve 13 into the passage 17.

【００１３】燃料定量機構Ｂは本体１５の下部に膜２４
を挟んでカバー２０を結合し、定圧燃料室２３と大気室
２５を区画する。定圧燃料室２３の内部にレバー１９が
軸２１により回動可能に支持される。レバー１９の一端
部は流入弁１８に係合され、流入弁１８がばね２２の力
を受けて通路１７の端部の弁座へ当接するように構成さ
れる。レバー１９の他端部は膜２４へ当接可能とされ、
膜２４の下面に作用する大気圧の力がばね２２の力より
も大きくなると、レバー１９が時計方向へ回動して流入
弁１８が開き、通路１７から燃料が定圧燃料室２３へ補
給され、こうして、定圧燃料室２３は所定量の燃料を所
定圧力に保持する。定圧燃料室２３の燃料は低速燃料計
量針弁２６、低速燃料噴孔２８を経て吸気路１６へ供給
される。また、定圧燃料室２３の燃料は逆止弁２９、高
速燃料計量針弁３０、高速燃料噴孔３１を経て吸気路１
６へ供給される。The fuel metering mechanism B has a membrane 24
, The cover 20 is connected, and the constant pressure fuel chamber 23 and the atmosphere chamber 25 are partitioned. A lever 19 is rotatably supported by a shaft 21 inside the constant-pressure fuel chamber 23. One end of the lever 19 is engaged with the inflow valve 18, and the inflow valve 18 is configured to abut a valve seat at the end of the passage 17 under the force of the spring 22. The other end of the lever 19 can contact the membrane 24,
When the atmospheric pressure acting on the lower surface of the membrane 24 becomes greater than the force of the spring 22, the lever 19 rotates clockwise to open the inflow valve 18, and fuel is supplied from the passage 17 to the constant pressure fuel chamber 23, Thus, the constant pressure fuel chamber 23 holds a predetermined amount of fuel at a predetermined pressure. The fuel in the constant pressure fuel chamber 23 is supplied to the intake passage 16 through the low speed fuel metering needle valve 26 and the low speed fuel injection hole 28. The fuel in the constant pressure fuel chamber 23 passes through a check valve 29, a high-speed fuel metering needle valve 30, and a high-speed fuel injection hole 31,
6.

【００１４】吸気路１６は弁軸１１により絞り弁２７を
回動可能に支持する。絞り弁２７は吸気路１６を開閉す
る円板状のものであり、ボルトにより弁軸１１へ結合さ
れ、周縁に切欠を形成される。絞り弁２７の前記切欠は
機関のアイドル運転時、低速燃料噴孔２８に接近され
る。The intake passage 16 rotatably supports the throttle valve 27 by the valve shaft 11. The throttle valve 27 is a disc-shaped one that opens and closes the intake passage 16, is connected to the valve shaft 11 by a bolt, and has a notch formed in the periphery. The notch of the throttle valve 27 approaches the low-speed fuel injection hole 28 when the engine is idling.

【００１５】このような膜型気化器は例えば特開昭59-2
0551号公報により公知であり、機関のいかなる姿勢（例
えば横転された状態）でも、燃料ポンプＡにより定圧燃
料室２３へ送られた燃料が、機関の吸気負圧により低速
燃料噴孔２８と高速燃料噴孔３１を経て吸気路１６へ供
給される。Such a film-type vaporizer is disclosed in, for example,
No. 0551, the fuel sent to the constant-pressure fuel chamber 23 by the fuel pump A in the low-pressure fuel injection hole 28 and the high-speed fuel The gas is supplied to the intake passage 16 through the injection hole 31.

【００１６】本発明によれば、機関の姿勢変化や急加速
運転で、機関へ供給される燃料量が異常に急増するのを
抑えるために、機関の吸気ポート４と気化器６との間に
接続される吸気路管５に、燃料を一時的に保留する発泡
樹脂、焼結金属などからなる多孔質部材３６が配設され
る。According to the present invention, in order to prevent the amount of fuel supplied to the engine from increasing abnormally due to a change in the attitude of the engine or a sudden acceleration operation, the engine is connected between the intake port 4 of the engine and the carburetor 6. A porous member 36 made of a foamed resin, a sintered metal, or the like that temporarily holds fuel is disposed in the connected intake passage pipe 5.

【００１７】図１，２に示すように、吸気路３４を有す
る吸気路管５の入口端部に大径円筒部３７を形成し、該
大径円筒部３７に環状の多孔質部材３６を嵌挿し、かつ
気化器本体１５との間に挟持する。多孔質部材３６には
吸気路３４の内径よりも小さい通孔３６ａが設けられ
る。換言すれば、多孔質部材３６の一部は吸気路管５か
ら吸気路３４の内部へ突出して配設される。As shown in FIGS. 1 and 2, a large-diameter cylindrical portion 37 is formed at the inlet end of the intake passage pipe 5 having the intake passage 34, and an annular porous member 36 is fitted into the large-diameter cylindrical portion 37. It is inserted and held between the carburetor body 15. The porous member 36 is provided with a through hole 36 a smaller than the inner diameter of the intake path 34. In other words, a part of the porous member 36 is disposed so as to protrude from the intake passage pipe 5 into the intake passage 34.

【００１８】なお、図２に示す気化器６は、公知のロー
タリ絞り弁式のものであり、吸気路１６と直交する円筒
部１５ａが本体１５に形成され、該円筒部１５ａに絞り
孔４５ｂを有する絞り弁４５が回動可能かつ昇降可能に
嵌挿される。絞り弁４５から上方へ突出する弁軸４５ａ
に絞り弁レバーが結合され、該絞り弁レバーと本体１５
との間のカム機構により、絞り弁４５をばねの力に抗し
て加速方向へ回動すると、絞り孔４５ｂが吸気路１６と
連通する開度が増加し、また、絞り弁４５から絞り孔４
５ｂへ突出しかつ燃料供給管４７へ嵌挿するニードル弁
４６が、燃料供給管４７の燃料噴孔４７ａから上昇し、
燃料噴孔４７ａの開度が増加する。不動の燃料供給管４
７は図示してない逆止弁を経て、図１に示すものと同様
の燃料定量機構Ｂの定圧燃料室２３へ連通される。The carburetor 6 shown in FIG. 2 is of a known rotary throttle valve type. A cylindrical portion 15a orthogonal to the intake passage 16 is formed in the main body 15, and a throttle hole 45b is formed in the cylindrical portion 15a. The throttle valve 45 is rotatably and vertically inserted. A valve shaft 45a projecting upward from the throttle valve 45
The throttle valve lever is connected to the
When the throttle valve 45 is rotated in the acceleration direction against the force of the spring, the opening degree at which the throttle hole 45b communicates with the intake passage 16 increases. 4
The needle valve 46 projecting to the fuel supply pipe 47 rises from the fuel injection hole 47a of the fuel supply pipe 47,
The opening of the fuel injection hole 47a increases. Immobile fuel supply pipe 4
Numeral 7 is connected through a check valve (not shown) to a constant-pressure fuel chamber 23 of a fuel metering mechanism B similar to that shown in FIG.

【００１９】次に、本発明による機関の吸気装置の作動
について説明する。機関のアイドル運転時、絞り弁２７
は図１に示す状態にあり、吸気路１６へ吸引された空気
の大部分は、絞り弁２７の切欠を経て低速燃料噴孔２８
に沿つて流れ、特に流速が速い絞り弁２７の下流側の低
速燃料噴孔２８から燃料を吸引し、吸気路管５へ流れ
る。Next, the operation of the intake system for an engine according to the present invention will be described. During idle operation of the engine, the throttle valve 27
1 is in the state shown in FIG. 1, and most of the air sucked into the intake passage 16 passes through the notch of the throttle valve 27,
In particular, fuel is sucked from the low-speed fuel injection holes 28 on the downstream side of the throttle valve 27 having a high flow velocity, and flows to the intake passage pipe 5.

【００２０】機関の始動時、吸気路管５を流れる吸気の
流速は遅いので、多孔質部材３６の吸気路３４への突出
部分に燃料が吸着されやすい。しかし、多孔質部材３６
に吸着された燃料が、機関の震動や姿勢変化に伴つて一
気に流出し、濃い混合気が機関へ供給されることはない
ので、始動不良を防ぐことができる。なぜなら、吸気の
流れに基づく静圧が作用する多孔質部材３６の表面積
（吸気路３４の中心軸方向の表面積）が小さいので、多
孔質部材３６に吸着された燃料が徐々に機関へ吸引さ
れ、このことから初爆時間が延び、暖気運転も容易にな
る。When the engine is started, the flow rate of the intake air flowing through the intake passage pipe 5 is low, so that the fuel is likely to be adsorbed to the protruding portion of the porous member 36 toward the intake passage 34. However, the porous member 36
The fuel adsorbed on the engine flows out at once with the vibration and attitude change of the engine, and a rich air-fuel mixture is not supplied to the engine. Because the surface area of the porous member 36 on which the static pressure based on the flow of the intake air acts (the surface area in the central axis direction of the intake passage 34) is small, the fuel adsorbed by the porous member 36 is gradually sucked into the engine, This extends the initial bombing time and facilitates warm-up operation.

【００２１】機関のアイドル運転でも、吸気路管５を流
れる吸気の流速が遅いので、多孔質部材３６の突出部分
に燃料が吸着されやすい。多孔質部材３６を通る燃料は
極く細かい燃料粒になるので燃料の気化が容易になり、
また、燃料の気化は吸気路管５の温度を下げるので、気
化器６の温度上昇が抑えられ、機関の安定した回転が得
られる。アイドル運転中に機関が傾斜しても、多孔質部
材３６に吸着された燃料が一気に機関へ流れ込むことは
ないので、機関停止は起こらず、安定した回転が得られ
る。Even when the engine is idling, the flow rate of the intake air flowing through the intake pipe 5 is low, so that the protruding portion of the porous member 36 tends to adsorb the fuel. Since the fuel passing through the porous member 36 becomes extremely fine fuel particles, the fuel is easily vaporized,
Further, since the vaporization of the fuel lowers the temperature of the intake passage pipe 5, the temperature rise of the carburetor 6 is suppressed, and stable rotation of the engine is obtained. Even if the engine is tilted during idling operation, the fuel adsorbed by the porous member 36 does not flow into the engine at a stretch, so that the engine does not stop and stable rotation can be obtained.

【００２２】機関の加速運転で、絞り弁２７を急に開く
と、空気は多孔質部材３６の中心を流れるが、この時多
孔質部材３６の通孔３６ａがベンチユリ効果を発揮し、
多孔質部材３６に吸着されている燃料が、一気に機関へ
吸引されることはない。つまり、多孔質部材３６に吸着
されている燃料は、徐々に少しずつ機関へ吸引されるの
で、空燃比が濃すぎることはなく、加速ポンプと同様の
作用効果を発揮する。さらに、絞り弁２７を全開で運転
を続けると、燃料噴孔２８，３１からの燃料の大部分が
空気とともに多孔質部材３６の中心の通孔３６ａを経て
機関へ吸引され、多孔質部材３６に吸着される燃料はご
く僅かである。したがつて、燃料の一部が多孔質部材３
６に吸着されることにより空燃比が薄くなることはな
い。When the throttle valve 27 is suddenly opened during the acceleration operation of the engine, air flows through the center of the porous member 36. At this time, the through hole 36a of the porous member 36 exhibits a bench lily effect.
The fuel adsorbed by the porous member 36 is not sucked into the engine at once. That is, since the fuel adsorbed by the porous member 36 is gradually sucked into the engine little by little, the air-fuel ratio does not become too rich, and the same operation and effects as those of the acceleration pump are exhibited. Further, when the throttle valve 27 is continuously operated with the throttle valve 27 fully opened, most of the fuel from the fuel injection holes 28 and 31 is sucked into the engine through the center through hole 36a of the porous member 36 together with the air, and Very little fuel is adsorbed. Therefore, a part of the fuel is
The air-fuel ratio is not reduced by being adsorbed by the air-fuel ratio 6.

【００２３】図２に示す吸気装置でも、図１のものと同
様に作動し、同様の作用効果が得られる。The operation of the intake device shown in FIG. 2 is the same as that of FIG.

【００２４】図３に示す変更実施例では、内燃機関の吸
気装置として、気化器６の吸気路１６の出口端部に大径
円筒部３８を形成し、大径円筒部３８に多孔質部材３６
を嵌合するとともに、吸気路管５と気化器本体１５との
間に挟んだものであり、図１のものと同様に作動し、同
様の作用効果が得られる。In the modified embodiment shown in FIG. 3, a large-diameter cylindrical portion 38 is formed at the outlet end of the intake passage 16 of the carburetor 6 as an intake device for an internal combustion engine.
Are fitted and sandwiched between the intake pipe 5 and the carburetor body 15, and operate in the same manner as in FIG. 1 to obtain the same operation and effect.

【００２５】[0025]

【発明の効果】本発明は上述のように、気化器の吸気路
を機関の吸気ポートへ接続する吸気路管の内周壁に多孔
質部材を配設したものにおいて、前記多孔質部材の内径
を吸気路管の内径よりも小さくしたものであり、環状の
多孔質部材が吸気路管の内部へ突出して設けられている
ので、多孔質部材が小形ながら吸着表面積が広くなり、
燃料が吸着されやすく、特に、多孔質部材の吸気路管の
内部へ突出する部分に、燃料が迅速に吸着される。つま
り、多孔質部材の外径を大きくしなくても、多孔質部材
の容積を増加でき、機関の始動時、初爆時間が延び、機
関の安定した運転が得られ、暖機運転が容易になる。According to the present invention, as described above, a porous member is disposed on the inner peripheral wall of an intake passage pipe connecting an intake passage of a carburetor to an intake port of an engine. It is smaller than the inner diameter of the intake pipe, and the annular porous member is provided so as to protrude into the intake pipe, so the adsorption surface area is increased while the porous member is small,
The fuel is easily adsorbed, and particularly, the fuel is quickly adsorbed on the portion of the porous member protruding into the intake pipe. In other words, the volume of the porous member can be increased without increasing the outer diameter of the porous member, the initial explosion time is increased at the start of the engine, the engine can be operated stably, and the warm-up operation can be easily performed. Become.

【００２６】多孔質部材が小形で燃料の吸着容量が大き
いので、機関が傾斜した時に過剰な燃料が急に機関へ流
入するのを防止できる。Since the porous member is small and has a large fuel adsorption capacity, it is possible to prevent excessive fuel from suddenly flowing into the engine when the engine is tilted.

【００２７】機関の運転中に多孔質部材を経由した燃料
は気化しやすくなり、気化性の向上により燃費が向上
し、また燃料の気化熱により吸気路管が冷却されるの
で、吸入効率が向上する。During the operation of the engine, the fuel passing through the porous member is easily vaporized, the fuel efficiency is improved by improving the vaporization property, and the intake passage pipe is cooled by the heat of vaporization of the fuel, so that the suction efficiency is improved. I do.

【００２８】機関の加速運転で絞り弁を急に開いた時
に、多孔質部材に吸着された燃料が少しずつ吸気路へ流
れ、加速ポンプと同様の作用をする。つまり、多孔質部
材のベンチユリ効果により、吸気が通孔へ集中して通過
するので、多孔質部材に吸着された燃料が一気に機関へ
供給されることがなく、排ガスの清浄化が期待でき、急
加速時に空燃比が濃すぎて機関が停止することもない。When the throttle valve is suddenly opened during the acceleration operation of the engine, the fuel adsorbed by the porous member flows into the intake passage little by little, and acts similarly to the acceleration pump. In other words, the intake air is intensively passed through the through hole by the bench lily effect of the porous member, so that the fuel adsorbed by the porous member is not supplied to the engine at once, so that the exhaust gas can be expected to be purified. The engine does not stop because the air-fuel ratio is too rich during acceleration.

【００２９】吸気路管の内部へ環状の多孔質部材を突出
して配設するだけの構造であり、構成が簡単であり、多
孔質部材を気化器の内部に設ければ、機関部分の変更は
一切不要になる。This is a structure in which an annular porous member is simply protruded and disposed inside the intake passage pipe. The structure is simple. If the porous member is provided inside the carburetor, the engine portion can be changed. It becomes completely unnecessary.

【００３０】機関の高速運転での多孔質部材による吸入
効率の低下はごく僅かである。In the high-speed operation of the engine, the decrease in the suction efficiency due to the porous member is very small.

【図面の簡単な説明】[Brief description of the drawings]

【図１】本発明に係る内燃機関の吸気装置の側面断面図
である。FIG. 1 is a side sectional view of an intake device for an internal combustion engine according to the present invention.

【図２】同吸気装置の要部を拡大して示す側面断面図で
ある。FIG. 2 is an enlarged side sectional view showing a main part of the intake device.

【図３】本発明の変更実施例に係る吸気装置の要部を拡
大して示す側面断面図である。FIG. 3 is an enlarged side sectional view showing a main part of an intake device according to a modified embodiment of the present invention.

【図４】従来の内燃機関の吸気装置の側面断面図であ
る。FIG. 4 is a side sectional view of a conventional intake device for an internal combustion engine.

【符号の説明】[Explanation of symbols]

Ａ：燃料ポンプ Ｂ：燃料定量機構 ４：吸気ポート
５：吸気路管 ６：気化器 ７：逆止弁 ８：入口
９：脈動圧室 １０：膜 １１：弁軸 １２：ポンプ室
１３：逆止弁 １４：カバー １５：本体 １５ａ：
円筒部 １６：吸気路 １７：通路 １８：流入弁 １
９：レバー ２０：カバー ２１：軸 ２２：ばね ２
３：定圧燃料室 ２４：膜 ２５：大気室 ２６：低速
燃料計量針弁 ２７：絞り弁 ２８：低速燃料噴孔 ２９：逆止弁 ３
０：高速燃料計量針弁 ３１：高速燃料噴孔 ３４：吸気路 ３６：多孔質部材
３６ａ：通孔 ３７：大径円筒部 ３８：大径円筒部
４０：燃料入口 ４５：絞り弁 ４５ａ：弁軸 ４
６：ニードル弁 ４５ｂ：絞り孔 ４７：燃料供給管
４７ａ：燃料噴孔 ５５：クランク室A: Fuel pump B: Fuel metering mechanism 4: Intake port
5: Intake path pipe 6: Vaporizer 7: Check valve 8: Inlet
9: Pulsating pressure chamber 10: Membrane 11: Valve shaft 12: Pump chamber 13: Check valve 14: Cover 15: Main body 15a:
Cylindrical part 16: Intake path 17: Passage 18: Inflow valve 1
9: lever 20: cover 21: shaft 22: spring 2
3: constant pressure fuel chamber 24: membrane 25: atmosphere chamber 26: low speed fuel metering needle valve 27: throttle valve 28: low speed fuel injection hole 29: check valve 3
0: high-speed fuel metering needle valve 31: high-speed fuel injection hole 34: intake path 36: porous member 36a: through hole 37: large-diameter cylindrical portion 38: large-diameter cylindrical portion 40: fuel inlet 45: throttle valve 45a: valve shaft 4
6: needle valve 45b: throttle hole 47: fuel supply pipe
47a: Fuel injection hole 55: Crank chamber

Claims (2)

【特許請求の範囲】[Claims] 【請求項１】気化器の吸気路を機関の吸気ポートへ接続
する吸気路管の内周壁に多孔質部材を配設したものにお
いて、前記多孔質部材の内径を吸気路管の内径よりも小
さくしたことを特徴とする内燃機関の吸気装置。A porous member disposed on an inner peripheral wall of an intake path pipe connecting an intake path of a carburetor to an intake port of an engine, wherein an inner diameter of the porous member is smaller than an inner diameter of the intake path pipe. An intake device for an internal combustion engine, comprising: 【請求項２】気化器の吸気路の出口端部に大径円筒部を
形成し、該大径円筒部に環状の前記多孔質部材を嵌合す
るとともに、前記吸気路管と前記気化器との間に挟ん
だ、請求項１に記載の内燃機関の吸気装置。2. A large-diameter cylindrical portion is formed at an outlet end of an intake passage of a carburetor, and the annular porous member is fitted into the large-diameter cylindrical portion. The intake device for an internal combustion engine according to claim 1, which is interposed between the intake devices.