JPS6198954A - Diaphragm type carburetor - Google Patents

Abstract

PURPOSE:To prevent air from infiltrating into a fuel chamber and improve reliability by simplified further low priced constitution, by providing a main nozzle and a low speed port respectively branching from a single fuel passage extended from the fuel chamber regulating the pressure of fuel almost to a fixed level. CONSTITUTION:A barrel 2 having an intake path 1 additionally provides a fuel pump 3 in one side further a pressure control part 4 in an opposite side. And the pressure control part 4 connects with its fuel chamber 10 a single fuel passage 15, further the fuel passage 15 successively provides a main jet 17, equipping a controllable needle valve 16, and a port chamber 18. Here a carburetor, opening both a main nozzle 20 to the narrowest part of a Venturi 19 in the intake path 1 and a low speed port 22 to the side of a throttle valve 21 in its closing position, connects the nozzle 20 and the port 22 respectively with the port chamber 18. In this way, a main and a low speed fuel system is constituted by the single fuel passage 15 and its branching main nozzle 20 and low speed port 22.

Description

【発明の詳細な説明】 産業上の利用分野 本発明は主としてｎ業用、園芸用の機械。[Detailed description of the invention] Industrial applications The present invention is mainly a machine for industrial use and gardening.

小形ａ両などの小形の汎用エンジンに燃料を供給する膜
式気化器に関するものである。This invention relates to a membrane carburetor that supplies fuel to small general-purpose engines such as small A-cars.

膜の受圧力に応じて燃料弁を開閉し燃料室の燃料圧力を
ほぼ一定に維持することによって吸気路へ吸出される燃
料を制御する形式の膜式気化器は、自動車用エンジンの
浮子式気化器と比較して著しく小形で枯造がｆｌ　、＠
であるばかりか、任意の姿勢で使用可能であるという特
徴なもっている。The membrane type carburetor is a type that controls the fuel sucked into the intake passage by opening and closing the fuel valve according to the pressure received by the membrane and maintaining the fuel pressure in the fuel chamber almost constant. It is noticeably smaller than the pottery, and the karezo is fl.
Not only that, but it also has the characteristic of being able to be used in any position.

ところで、このような模式気化ｉ！ｉは燃料系に主系統
と低連系統とを具えるのが普通であって、これら二つの
系統の燃料通路は燃料室から各別に独立して設けられて
いる。By the way, such a model vaporization i! Normally, the fuel system of the i is equipped with a main system and a low connection system, and the fuel passages for these two systems are provided separately from the fuel chamber.

このため、エンジンのアイドリンク時に主ノズルから主
系統を通って燃料室に空気が入り燃料圧力を狂わせ、従
ってアイドリンク時に低速系統によって供給される燃料
を不正確としまた低速燃料から主燃料への切換えを不円
滑とするなどの問題を生じる。その対策として、第３図
に示したように主ノズル２１の前方に逆上弁２２を設け
、アイドリング時にベンチュリ２３を流れる空気が主惺
料通路２４を通って燃料室２５に入らないようにするこ
とが行われているが、構造が複雑となり且つ価格もそれ
だけ高価になるばかりか、逆止弁の開き遅れにより主燃
料の噴出開始時期が遅れることがあるという欠点を伴う
、 本発明は前記のような開明を解決し、きわめて簡単な柳
成で空気が燃料室へ入ることのない膜式気化器を提供す
るものであって、燃料圧力をほぼ一定に調整する燃料室
から延びる凰−の燃′＃＋通路に主ノズルと低速ボート
とをそれぞれ分岐させて設けたことによって前記間頓点
を解決するための手段とした、実　　施　　例 本発明の実杓例を図面に基いて説明オろと。For this reason, when the engine is idle, air enters the fuel chamber from the main nozzle through the main system and disturbs the fuel pressure, thus making the fuel supplied by the slow system inaccurate during engine idle, and causing the flow from slow fuel to main fuel to be inaccurate. This causes problems such as unsmooth switching. As a countermeasure, a reverse valve 22 is provided in front of the main nozzle 21 as shown in FIG. 3 to prevent the air flowing through the venturi 23 during idling from entering the fuel chamber 25 through the main fuel passage 24. However, the structure is complicated and the price is correspondingly high, and the main fuel injection start timing may be delayed due to the delay in opening of the check valve. The purpose of this invention is to solve this problem and provide a membrane type carburetor that does not allow air to enter the fuel chamber with an extremely simple configuration. A practical example of the present invention will be explained based on the drawings, in which the main nozzle and the low-speed boat are provided separately in the passageway to solve the above-mentioned problem. and.

吸気路１を有する胴体２の一つの側面に燃料ポンプ３が
附設されているとともに反対の側面に調圧部４が附設さ
れている。A fuel pump 3 is attached to one side of a body 2 having an intake passage 1, and a pressure regulating section 4 is attached to the opposite side.

燃料ポンプ３はエンジンのクランクケースに発生する脈
動圧力がパルス室５に導入されて膜６を往復動させるこ
とによって燃料の吸込み、吐出を行うもので、ポンプ室
７から吐出された燃料に送出Ａ路８から燃料弁９を経て
調圧部４の燃料室１０に送り込まれる。The fuel pump 3 sucks and discharges fuel by introducing pulsating pressure generated in the engine crankcase into a pulse chamber 5 and reciprocating a membrane 6. The fuel is sent from the passage 8 to the fuel chamber 10 of the pressure regulating section 4 via the fuel valve 9.

調圧部４は燃料室１０．大気室１１．１１！ｉ￥１２．
腕１３を具え、燃料室１００慾料が減少すると膜１２が
燃料室１０の方へ移動して腕１３を回動しその先端に接
触係合した燃料弁９をばね１４０弾性力に抗して開弁さ
せ、燃料が一定以上に送り込まれると膜１２が大気室１
１の方へ移動して燃料弁９を閉弁させることによって燃
料室１０の燃料圧力をほぼ一定に調整するもので、これ
は従来の膜式気化器と同じである。The pressure regulating section 4 has a fuel chamber 10. Atmospheric chamber 11.11! i￥12.
The membrane 12 moves toward the fuel chamber 10, rotates the arm 13, and presses the fuel valve 9, which is in contact with the tip of the arm 13, against the elastic force of the spring 140. When the valve is opened and fuel is fed above a certain level, the membrane 12 enters the atmospheric chamber 1.
1 and closes the fuel valve 9, the fuel pressure in the fuel chamber 10 is adjusted to a substantially constant level, which is the same as in the conventional membrane type carburetor.

前記燃料室１０には融−Ｃ−Ｐ、料通路１５が接続され
て居り、この・燃料通路１５は可調整の針弁１６を具え
た主ジェツト１７とボート室１８とを順に有し、吸気路
１のペンチュＩＪ１９の最狭部に開口した主ノズル２０
および閉弁位置の絞り弁２１の側方に開口した低速ボー
ト２２が前記ボート室１８に接続して設けられている。A fuel passage 15 is connected to the fuel chamber 10, and the fuel passage 15 has a main jet 17 equipped with an adjustable needle valve 16 and a boat chamber 18 in order. Main nozzle 20 opened at the narrowest part of Pentu IJ19 on Route 1
A low-speed boat 22 is connected to the boat chamber 18 and is open to the side of the throttle valve 21 in the closed position.

第２図の実施例では燃料Ａ路１５の主ジェツト１７とボ
ート室１８との間に主ノズル２０を接続しボート室１８
に低速ボート２２を接続した。In the embodiment shown in FIG.
Low-speed boat 22 was connected to.

このような槽底の二つの実施例において。In two embodiments of such tank bottoms.

絞り弁２１の一度が大きいときは主ノズル２０に作用す
る高いベンチュリ負圧によってＰ料が主ノズル２０から
吸気路１に吸出され、管り弁２１がアイドル開度のとき
はその下流側に開口した低速ボート２２から燃料が吸気
路１に吸出される。アイドリング時にはベンチュリ負圧
がぎわめて弱く主ノズル２０から生気が燃料通路１５へ
向って吸込まれるか、この空気は高負圧が作用している
低速ボート２２へ向って流れ。When the opening of the throttle valve 21 is large, the high venturi negative pressure acting on the main nozzle 20 causes the P material to be sucked out from the main nozzle 20 into the intake passage 1, and when the pipe valve 21 is at the idle opening, the P material is opened on the downstream side thereof. Fuel is sucked out into the intake passage 1 from the low-speed boat 22 that has been driven. During idling, the venturi negative pressure is extremely weak and fresh air is sucked from the main nozzle 20 toward the fuel passage 15, or this air flows toward the low-speed boat 22 where high negative pressure is applied.

低速燃料のブリード空気として働く。Acts as a slow fuel bleed air.

本発明によると、・黙料糸の主系統と低速系統とを蛛−
の燃料通路およびこれより分岐した主ノズル、低速ボー
トによって構成したので、燃料系の構成が著しく簡単な
ものとなｐ。According to the present invention, the main system and the slow system of the silent thread are connected to each other.
The fuel system consists of a fuel passage, a main nozzle branching from this, and a low-speed boat, making the fuel system extremely simple.

またアイドリンク時に主ノズルから吸込まれた空気は低
速８料のブリード空気となって低速ボートから吸気路へ
吸出されるので燃料室へ逆流することがなく、従って空
気吸込み防止の逆上弁を主ノズルに設ける必要がな（な
るととも恍アイドリング時の安定した燃料供給と低速ｅ
科から主燃料への円滑な切換えとが期待されるものでろ
る。In addition, the air sucked in from the main nozzle during idle link becomes low-speed 8-fuel bleed air and is sucked out from the low-speed boat to the intake passage, so it does not flow back into the fuel chamber. There is no need to install it in the nozzle (it also improves stable fuel supply during idling and low speed e).
It is expected that there will be a smooth transition from fuel to primary fuel.

【図面の簡単な説明】[Brief explanation of the drawing]

第１図は本発明の実施例の縦断面図、第２図は異なる実
施例の縦断面部分図、第３図は従来例の縦断面部分図で
ある。 １・・・・・吸気路、４・・・・・・調圧部、９・・・
・・・燃５弁、１０・・・・・・燃料室、１２・・曲・
椀、１５・・・・・・燃料通路、２０・・・・・・主ノ
ズル、２２・・・・・・低速ボート。FIG. 1 is a vertical cross-sectional view of an embodiment of the present invention, FIG. 2 is a partial vertical cross-sectional view of a different embodiment, and FIG. 3 is a partial vertical cross-sectional view of a conventional example. 1...Intake path, 4...Pressure regulating section, 9...
...Fuel valve 5, 10...Fuel chamber, 12...Song...
Bowl, 15... Fuel passage, 20... Main nozzle, 22... Low speed boat.

Claims (3)

【特許請求の範囲】[Claims] （１）燃料圧力をほぼ一定に調整する燃料室から延びる
単一の燃料通路に主ノズルと低速ポ ートとをそれぞれ分岐させて設けたことを 特徴とする膜式気化器。(1) A membrane carburetor characterized in that a main nozzle and a low-speed port are branched into a single fuel passage extending from a fuel chamber that adjusts fuel pressure to a substantially constant level. （２）主ノズルおよび低速ポートが燃料通路のポート室
に接続して設けられている特許請求 の範囲（１）に記載の膜式気化器。(2) The membrane carburetor according to claim (1), wherein the main nozzle and the low-speed port are connected to a port chamber of the fuel passage. （３）主ノズルが燃料通路の主ノズルとポート室との間
に接続して設けられ、低速ポートが 前記ポート室に接続して設けられている特 許請求の範囲（１）に記載の膜式気化器。(3) The membrane type according to claim (1), wherein the main nozzle is connected between the main nozzle of the fuel passage and the port chamber, and the low-speed port is connected to the port chamber. vaporizer.