JPS60138260A - Carburettor - Google Patents

Abstract

PURPOSE:To prevent the running ability of an engine from being deteriorated due to discharge of unnecessary fuel, by disposing a change-over valve in an inner vent passage communicating between the inlet port and the float chamber in a carburettor so that the change-over valve is opened only when supercharged pressure is abnormally raised, to introduce the atmospheric pressure into the float chamber. CONSTITUTION:When the pressure PT of intake-air in a carburettor 1 is high just before deceleration of a vehicle, a throttle valve 2 is abruptly closed to increase the pressure PIM of intake-air pipe so that the pressure PA in a venturi section 3 is abruptly lowered. However, since a float chamber 4 is communicated to the outside thereof through constriction given by a main jet 5 and an acceleration pump nozzle 6, the pressure of the float chamber 4 is maintained high for a while. Further, in the inner vent passage 13 there is provided a change-over valve mechanism composed of a valve seat 14 and a valve element 15 so that the valve side outlet port thereof is opened to the passage 13 and as well the other end thereof is opened to the atmospheric side. With this arrangement if supercharged pressure which is effected from the inlet port of the carburettor 1 exceeds a predetermined value, the valve 15 is opened so that the pressure of the float chamber 4 is made near to the atmospheric pressure.

Description

【発明の詳細な説明】 〔発明の利用分野〕 本発明は、過給機付エンジン用気化器に係り、特に、高
過給運転後の減速時における走行性の向上を達成できる
気化器の提供に関する。[Detailed Description of the Invention] [Field of Application of the Invention] The present invention relates to a carburetor for a supercharged engine, and in particular, to provide a carburetor that can improve running performance during deceleration after highly supercharged operation. Regarding.

〔発明の背景〕[Background of the invention]

従来、特開昭５６−６６４４３号公報にあるような過給
機用気化器においては高過給運転後の減速時に、気化器
のメインノズルや加速ポンプノズルより不必要な燃料が
吐出し、走行性を阻害するという現象があった。Conventionally, in a turbocharger carburetor such as that disclosed in Japanese Patent Application Laid-Open No. 56-66443, unnecessary fuel is discharged from the main nozzle of the carburetor or the acceleration pump nozzle during deceleration after high-supercharging operation, causing the engine to run. There was a phenomenon that inhibited sexuality.

この現象は、車輛の減速時、その初期において、減速直
前の高い過給圧が過給機の慣性動作により気イ鴫器吸気
筒内に作用する時、気化器のベンチュリ一部圧力より浮
子室内の圧力が異常に高くなるために、浮子室とベンチ
ュリ一部との圧力差によって、浮子室の燃料がメインノ
ズルや加速ポンプノズルより吐出するものである。この
圧力差の発生原因は、ベンチュリ一部の圧力は絞弁周囲
の隙間の存在で吸入負圧が作用するため、短時間で大気
圧に近ずくが、浮子室内の圧力は、出口がメインジェッ
トや加速ポンプノズルで絞られているため、比較的長い
時間、高圧（減速初期の過給圧に近い値）を保持するこ
ととなり、ここで成る時間ベンチュリ一部と浮子室間に
大きな圧力差が生ずるためである。This phenomenon occurs when the vehicle decelerates, and at the beginning of the deceleration, when the high supercharging pressure just before deceleration acts on the air intake cylinder due to the inertia of the supercharger, the partial pressure of the venturi of the carburetor causes Because the pressure in the float chamber becomes abnormally high, the fuel in the float chamber is discharged from the main nozzle or the acceleration pump nozzle due to the pressure difference between the float chamber and a portion of the venturi. The cause of this pressure difference is that the pressure in the venturi reaches close to atmospheric pressure in a short time due to the presence of a gap around the throttle valve and negative suction pressure, but the pressure in the float chamber is Because it is throttled by the accelerator pump nozzle, a high pressure (close to the supercharging pressure at the beginning of deceleration) is maintained for a relatively long time, and during this time a large pressure difference occurs between the venturi part and the float chamber. It's for a reason.

〔発明の目的〕[Purpose of the invention]

本発明の目的はかかる不具合現象を解消した燃料が過剰
に供給されない気化器を得ることにある。An object of the present invention is to provide a carburetor which eliminates such troubles and prevents fuel from being excessively supplied.

〔発明の概要〕[Summary of the invention]

本発明の特徴は減速時に浮子室に大気圧を導入し、浮子
室圧力をベンチュリ一部の圧力以下になるように構成し
たものである。A feature of the present invention is that atmospheric pressure is introduced into the float chamber during deceleration, so that the pressure in the float chamber is lower than the pressure of a part of the venturi.

〔発明の実施例〕[Embodiments of the invention]

第１図において気化器入口と浮子室を結ぶ、いわゆるイ
ンナーベント通路の途中に、１方向切換弁を設け、該弁
は開放状態では浮子室と大気圧と気化器入口の３方向が
同時に連通するように構成されている。過給が必要な通
常の運転時は気化器入口の圧力は０．４〜０．５　Ｋｇ
　／　ｃ、ｒＡ程度であるのに対し、減速時は、０．７
〜０．８　Ｋ９／　ｃｄなる。従来構造ではこの１寺、
前述の如く、メインノズル熔から栄分な燃料か吐出され
るか、ここで、前記切換弁の開弁圧ｉ　０．５１ソ／　
ｃｒ１以上に設定すれは、高い過給圧は大気圧側へ抜け
、浮子室の圧力を高めるととｅまない。又、この切換弁
として電磁弁を使用し、車輛の減速状態を検出するスイ
ッチ等の組み合せで、減速時のみ開弁することでも、前
記と同等の効果を出すことが出来る。In Fig. 1, a one-way switching valve is installed in the middle of the so-called inner vent passage that connects the carburetor inlet and the float chamber, and when the valve is open, the float chamber, atmospheric pressure, and the carburetor inlet communicate at the same time. It is configured as follows. During normal operation when supercharging is required, the pressure at the carburetor inlet is 0.4 to 0.5 Kg.
/ c, rA, while during deceleration it is 0.7
~0.8 K9/cd. In the conventional structure, this one temple,
As mentioned above, when the rich fuel is discharged from the main nozzle melt, the opening pressure i of the switching valve is 0.51 so/
If it is set to cr1 or more, the high supercharging pressure will escape to the atmospheric pressure side, increasing the pressure in the float chamber. Furthermore, the same effect as described above can be achieved by using a solenoid valve as the switching valve and opening the valve only when decelerating by combining it with a switch that detects the deceleration state of the vehicle.

発明の実施例とその効果 以下、本発明の実施例を図により説明する。Examples of the invention and its effects Embodiments of the present invention will be described below with reference to the drawings.

第１図において、車軸の減速直前に、気化器１の吸気圧
ＰＴが商い時、次に絞弁２が急激に閉じ、吸気管負圧Ｐ
！Ｍが高くなると、ベンチュリ一部３の圧力ＰＡは急激
に低くなるが、浮子室４に作用する圧力Ｐ　ｒ　ｌ’ｊ
：　、外部との連通がメインジェット５、加速ポンプノ
ズル６により紋られているため、急激な圧力低下が望め
ず、しばらくは大きな圧力を保持した１−である。この
場会、本発明に関する切換弁構造が存在しない状態では
、ベンチュリ一部圧力ＰＡと浮子室内圧力ＰＦとの差圧
のため、浮子室燃料はメインジェットを通りメイン燃料
通路８を経由して、メインノズル９より吸気筒内へ吐出
されたり、加速ポンプ室１１から、加速燃料通路１２を
経由して、加速ポンプノズルより吸気筒内に吐出される
。In Fig. 1, immediately before the axle decelerates, when the intake pressure PT of the carburetor 1 is low, the throttle valve 2 suddenly closes, and the intake pipe negative pressure P
! As M increases, the pressure PA in the venturi part 3 decreases rapidly, but the pressure acting on the float chamber 4 P r l'j
: Since communication with the outside is blocked by the main jet 5 and the acceleration pump nozzle 6, a rapid pressure drop cannot be expected, and the high pressure is maintained for a while. At this time, in a state where the switching valve structure according to the present invention does not exist, due to the pressure difference between the venturi partial pressure PA and the float chamber pressure PF, the float chamber fuel passes through the main jet and the main fuel passage 8. The fuel is discharged from the nozzle 9 into the intake cylinder, or from the acceleration pump chamber 11 via the acceleration fuel passage 12 and discharged from the acceleration pump nozzle into the intake cylinder.

一方、本発明に係る構造を附加した状態においては、イ
ンナーベント通路１３の途中に、弁座１４、弁１５、バ
ネ部材１６より構成される切換弁機構を設け、該切換弁
の弁座側出口はインナーベント通路に開口し、他端は大
気圧側に開口するように構成されているため、気化器入
口から作用する過給圧が所定値より高くなると、バネ部
材の閉弁力に抗して、弁が押され、弁座部が開放される
の゛で、浮子室の圧力は大気圧に近すくことになる。On the other hand, in a state where the structure according to the present invention is added, a switching valve mechanism composed of a valve seat 14, a valve 15, and a spring member 16 is provided in the middle of the inner vent passage 13, and an outlet on the valve seat side of the switching valve is provided. is configured to open to the inner vent passage and the other end to the atmospheric pressure side, so if the supercharging pressure acting from the carburetor inlet becomes higher than a predetermined value, the valve will resist the closing force of the spring member. Then, the valve is pushed and the valve seat is opened, so the pressure in the float chamber approaches atmospheric pressure.

又、他の実施例を第２図で説明すると、切換弁として電
磁弁１７を使用し、該電磁弁は、減速状態を検知するス
イッチ類１８．１９等の組み合せによる信号を受けて、
減速時に開弁し、第１の実施例と同様に、減速初期の高
過給圧時、浮子室の圧力を大気圧に近づけることができ
る。Another embodiment will be described with reference to FIG. 2, in which a solenoid valve 17 is used as the switching valve, and the solenoid valve receives a signal from a combination of switches 18, 19, etc. that detect the deceleration state, and
The valve opens during deceleration, and as in the first embodiment, the pressure in the float chamber can be brought close to atmospheric pressure when the boost pressure is high at the beginning of deceleration.

〔発明の効果〕〔Effect of the invention〕

以上により、本発明の効果としては、いかなる減速運転
においても、浮子室の圧力が異常に畠くなることで、不
必要な燃料が吸気筒内に吐出することがなく、運転性の
良好な気化器を提供できる。As described above, the effect of the present invention is that the pressure in the float chamber becomes abnormally high during any deceleration operation, so that unnecessary fuel is not discharged into the intake cylinder, and the vaporization with good drivability is achieved. We can provide equipment.

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

第１図は、本発明の第１実施例を示す気化器の　□断面
図、第２図は、本発明の第２実施例を示す、気化器の部
分図と回路図である。 １・・・気化器、２・・・絞弁、３・・・ベンチュリＴ
ｆＶ’、４・・・浮子室、５・・・メインジェット、６
・・・加速ポンプノズル、８・・・メイン燃料通路、９
・・・メインノズル、１０・・・吸気筒、１１・・・加
速ポンプ室、１２・・・加速燃料通路、１３・・・イン
ナーベント通路、１４・・・弁座、１５・・・弁、１６
・・・バネ部材、１７・・・電磁弁、１８・・・スイッ
チ、１９・・・スイッチ。 代理人　弁理士　高橋明夫FIG. 1 is a sectional view of a carburetor according to a first embodiment of the present invention, and FIG. 2 is a partial diagram and circuit diagram of a carburetor according to a second embodiment of the present invention. 1... Carburetor, 2... Throttle valve, 3... Venturi T
fV', 4... Float chamber, 5... Main jet, 6
...Acceleration pump nozzle, 8...Main fuel passage, 9
Main nozzle, 10 Intake cylinder, 11 Acceleration pump chamber, 12 Acceleration fuel passage, 13 Inner vent passage, 14 Valve seat, 15 Valve, 16
...Spring member, 17...Solenoid valve, 18...Switch, 19...Switch. Agent Patent Attorney Akio Takahashi

Claims (1)

【特許請求の範囲】 １、過給機付エンジン用で過給機の下流に気化器が配設
された構成のものにおいて、気化器入口と浮子室間を連
通ずるインナーベント通路の途中に、切替弁を設置し、
過給圧の異常上昇時のみ該切替弁が開弁作動し、浮子室
に大気圧が作用するように構成したことを特徴とする気
化器。 ２、特許請求の範囲第１項において、前記切替弁は、１
個の弁体と１個のバネ部材とで構成され、気化器入口圧
力の大きさによって、開弁するように構成された気化器
。 ３、特許請求の範囲第１項において、前記切替弁は電磁
弁で構成され、減速時などの条件を検出するスイッチの
組合せにより、所定の条件の時のみ電磁弁に通電し、開
弁するように構成された気化器[Claims] 1. In a supercharged engine with a carburetor disposed downstream of the supercharger, in the middle of the inner vent passage communicating between the carburetor inlet and the float chamber, Install a switching valve,
A carburetor characterized in that the switching valve is opened only when boost pressure increases abnormally, and atmospheric pressure acts on the float chamber. 2. In claim 1, the switching valve comprises 1
This carburetor is constructed of two valve bodies and one spring member, and is configured to open depending on the magnitude of the carburetor inlet pressure. 3. In claim 1, the switching valve is constituted by a solenoid valve, and the solenoid valve is energized and opened only under a predetermined condition by a combination of switches that detect conditions such as deceleration. vaporizer configured with