JPH11315722A - Two-cycle engine - Google Patents

Two-cycle engine

Info

Publication number
JPH11315722A
JPH11315722A JP13419398A JP13419398A JPH11315722A JP H11315722 A JPH11315722 A JP H11315722A JP 13419398 A JP13419398 A JP 13419398A JP 13419398 A JP13419398 A JP 13419398A JP H11315722 A JPH11315722 A JP H11315722A
Authority
JP
Japan
Prior art keywords
scavenging
cylinder
passage
gas
port
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.)
Granted
Application number
JP13419398A
Other languages
Japanese (ja)
Other versions
JP3404288B2 (en
Inventor
Kinichi Kato
欽一 加藤
Shigetoshi Ishida
茂敏 石田
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Tanaka Kogyo Co Ltd
Original Assignee
Tanaka Kogyo Co Ltd
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Tanaka Kogyo Co Ltd filed Critical Tanaka Kogyo Co Ltd
Priority to JP13419398A priority Critical patent/JP3404288B2/en
Publication of JPH11315722A publication Critical patent/JPH11315722A/en
Application granted granted Critical
Publication of JP3404288B2 publication Critical patent/JP3404288B2/en
Anticipated expiration legal-status Critical
Expired - Fee Related legal-status Critical Current

Links

Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02F—CYLINDERS, PISTONS OR CASINGS, FOR COMBUSTION ENGINES; ARRANGEMENTS OF SEALINGS IN COMBUSTION ENGINES
    • F02F3/00—Pistons 
    • F02F3/24—Pistons  having means for guiding gases in cylinders, e.g. for guiding scavenging charge in two-stroke engines
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02F—CYLINDERS, PISTONS OR CASINGS, FOR COMBUSTION ENGINES; ARRANGEMENTS OF SEALINGS IN COMBUSTION ENGINES
    • F02F1/00—Cylinders; Cylinder heads 
    • F02F1/18—Other cylinders
    • F02F1/22—Other cylinders characterised by having ports in cylinder wall for scavenging or charging
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02B—INTERNAL-COMBUSTION PISTON ENGINES; COMBUSTION ENGINES IN GENERAL
    • F02B75/00—Other engines
    • F02B75/02—Engines characterised by their cycles, e.g. six-stroke
    • F02B2075/022—Engines characterised by their cycles, e.g. six-stroke having less than six strokes per cycle
    • F02B2075/025—Engines characterised by their cycles, e.g. six-stroke having less than six strokes per cycle two

Landscapes

  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Combustion Methods Of Internal-Combustion Engines (AREA)
  • Cylinder Crankcases Of Internal Combustion Engines (AREA)

Abstract

PROBLEM TO BE SOLVED: To increase the rate of fuel consumption, while decreasing hydrocarbon in the exhaust gas greatly by circulating the scavenge gas of a proper concentration from the scavenging port to the combustion chamber of the cylinder head effectively without leaking out of unburnt gas from the exhaust port. SOLUTION: In the scavenging gas passage of this turning scavenging type two-cycle engine, the scavenge gas in a crankcase 7 is sent off via a narrow and horizontal scavenge gas release passage 11 over the crank case into the bottom of a scavenging passage of a cylinder 1 from the side of an exhaust port 4. Accordingly, the scavenge gas is separated into a thick gas comprising fuel particles having a large mass and a thin gas comprising fuel particles having a small mass before the gas is introduced to the scavenge port 5 located in the upper part. The scavenge gas thus introduced into the cylinder 1 is lifted in a loop from the inner wall opposite to an exhaust port 4 toward the cylinder head by a deflector 14 at the piston top. As a result, leaking out of unburnt gas from the exhaust port 4 is eliminated, and combustion efficiency in a combustion chamber 18 is improved.

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、反転掃気式２サイ
クルエンジン、詳細には、掃気通路を改良した反転掃気
式２サイクルエンジンの構成に関するものである。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a reversing scavenging two-cycle engine, and more particularly, to a reversing scavenging two-cycle engine having an improved scavenging passage.

【０００２】[0002]

【従来の技術】従来より、この種の反転掃気式２サイク
ルエンジンとしては、シュニーレ式２サイクルエンジン
がよく知られている。このエンジンでは、混合気が、気
化器から吸気ポートを介してクランクケース内に送り込
まれ、クランクケース内で上方のピストンが下降するこ
とに伴う圧縮力を与えられてから、クランクケースとシ
リンダの壁面内に設けられた通路を通して、掃気ガスと
してシリンダの掃気ポートよりシリンダ内へ送り込まれ
る。2. Description of the Related Art A chenille two-stroke engine is well known as a reversing scavenging two-stroke engine of this type. In this engine, an air-fuel mixture is sent from a carburetor through an intake port into a crankcase, and is given a compressive force caused by a descending upper piston in the crankcase. The gas is sent into the cylinder as a scavenging gas from a scavenging port of the cylinder through a passage provided therein.

【０００３】掃気ガスをシリンダ内へ送り込む掃気ポー
トは、その口の開く方向がシリンダ内における排気ポー
トと反対側の壁面の方向に向けられている。そのため前
記掃気ポートからシリンダ内へ送り込まれた掃気ガス
は、前記排気ポートと反対側の壁面に沿ってループ状に
上昇しながらシリンダヘッドの方向へ導かれ、ピストン
の上昇により圧縮されたところで点火される。[0003] The scavenging port for sending scavenging gas into the cylinder has its opening directed toward the wall surface opposite to the exhaust port in the cylinder. Therefore, the scavenging gas sent into the cylinder from the scavenging port is guided toward the cylinder head while rising in a loop along the wall surface opposite to the exhaust port, and is ignited when compressed by the rise of the piston. You.

【０００４】掃気ガスの燃焼によりピストンが下降する
と、排気ガスは排気ポートからシリンダ外へ排出される
が、そのとき掃気ポートからシリンダ内へ次の新しい掃
気ガスが送り込まれるため、シリンダ内に完全に排出し
きれずに残っていた排気ガスの一部は排気ポートからシ
リンダ外へ排出される。When the piston descends due to the combustion of the scavenging gas, the exhaust gas is discharged from the exhaust port to the outside of the cylinder. At that time, the next new scavenging gas is sent from the scavenging port into the cylinder, so that the exhaust gas completely enters the cylinder. A part of the exhaust gas remaining without being exhausted is exhausted from the exhaust port to the outside of the cylinder.

【０００５】[0005]

【発明が解決すべき課題】このシュニーレ式２サイクル
エンジンでは、掃気ポートからシリンダ内へ送り込まれ
た掃気ガスを、排気ポートと反対側の壁面に沿ってシリ
ンダヘッドの方向へループ状に上昇させて、掃気作用を
行うことができるという利点をもつ反面、掃気ガスが掃
気ポートからシリンダ内に送り込まれた直後に未燃状態
のまま排気ポートから直接外部へ漏出してしまうことが
あり、この未燃状態のガスはハイドロカーボン（ＨＣ）
であるため公害の原因となっている。In the Schnille type two-cycle engine, scavenging gas sent from the scavenging port into the cylinder is raised in a loop toward the cylinder head along the wall surface opposite to the exhaust port. Although it has the advantage of being able to perform a scavenging action, the scavenging gas may leak out of the exhaust port directly to the outside in an unburned state immediately after being sent into the cylinder from the scavenging port. The gas in the state is hydrocarbon (HC)
Therefore, it causes pollution.

【０００６】シュニーレ式２サイクルエンジンが上記の
ような問題が発生する理由は、この方式のエンジンで
は、掃気ポートからシリンダ内へ送り込まれた掃気ガス
を、排気ポートと反対側の壁面に沿ってシリンダヘッド
の方向へループ状に流すことで、効率のよい掃気作用を
得るために、ピストンの上端面を凹凸のない平面とし
て、掃気ポートからシリンダ内へ送り込まれた掃気ガス
が排気ポートと反対側の壁面方向へ円滑に流れるように
していることに起因している。The reason that the above problem occurs in the Schnille type two-cycle engine is that, in this type of engine, scavenging gas sent from the scavenging port into the cylinder is transferred to the cylinder along the wall surface opposite to the exhaust port. In order to obtain an efficient scavenging action by flowing in a loop toward the head, the scavenging gas sent into the cylinder from the scavenging port and the scavenging gas on the opposite side to the exhaust port is used as the top surface of the piston is a flat surface without unevenness. This is due to the smooth flow toward the wall surface.

【０００７】ピストンの上端面が凹凸のない平面である
と、掃気ポートから送り込まれる掃気ガスは、掃気ポー
トが向けられた方向へ放出されるが、シリンダ内に放出
された瞬間に拡散されるため、シリンダの内壁面に沿っ
て長い距離をループ状に流出する層と、この層の内側、
即ちシリンダ内の中心部方向へ流出する層とができて、
このシリンダ内の中心部方向へ流出する層が排気ポート
から未燃状態のガスのまま外部に漏出してしまうことに
なる。If the upper end surface of the piston is a flat surface without irregularities, the scavenging gas sent from the scavenging port is discharged in the direction in which the scavenging port is directed, but is diffused at the moment when the scavenging gas is discharged into the cylinder. A layer that flows in a loop over a long distance along the inner wall surface of the cylinder, and the inside of this layer,
That is, there is a layer flowing out toward the center of the cylinder,
The layer flowing toward the center of the cylinder leaks out of the exhaust port to the outside as unburned gas.

【０００８】このような、シリンダ内に送り込まれた掃
気ガスの一部が未燃状態のガスのまま排気ポートから外
部へ漏出するという問題を解消するための手段として、
掃気ポートからシリンダ内へ送り込まれる掃気ガスを、
シリンダの内壁面に沿ってシリンダヘッド方向へループ
状に流すのではなく、ピストンの真上からシリンダ内の
中心部分を通って直接シリンダヘッドの方向へ流すよう
にした掃気方式が実開昭５９−２８６２８号により知ら
れている。As a means for solving such a problem that a part of the scavenging gas sent into the cylinder leaks from the exhaust port to the outside as unburned gas,
The scavenging gas sent from the scavenging port into the cylinder is
The scavenging method in which the gas flows directly from the top of the piston to the cylinder head through the central portion of the cylinder instead of flowing in a loop along the inner wall surface of the cylinder in the direction of the cylinder head has been proposed. No. 28628 is known.

【０００９】この掃気方式では、ピストンの上端部に、
該ピストンの上端部の側面から上面に通ずるような掃気
案内通路を設けて、掃気ガスをシリンダの内壁面に開口
した掃気ポートからこの掃気案内通路を通して、ピスト
ンの上面に開口した実質的な掃気ポートとしての該掃気
案内通路出口から直接上方のシリンダヘッドの方向へ送
り込む。In this scavenging method, the upper end of the piston is
A scavenging guide passage extending from the side surface of the upper end of the piston to the upper surface, and a scavenging gas opening the upper surface of the piston from the scavenging port opened to the inner wall surface of the cylinder through the scavenging guide passage. From the outlet of the scavenging guide passage, and is fed in the direction of the upper cylinder head.

【００１０】しかしながら、この方式は、掃気ガスが、
ピストンの上面に開口した掃気ポートとしての掃気案内
通路の出口から、シリンダ内の中心部分を通ってシリン
ダヘッドの方向へ流れるので、掃気ガスをシリンダヘッ
ドの方向へ効率よく誘導することには適しているとして
も、掃気ガスが爆発燃焼した後に生ずる排気ガスを全て
確実に排気ポートから排気させることができず、排気ガ
スの一部がシリンダ内に残留するという問題を有してい
る。However, in this method, the scavenging gas is
From the outlet of the scavenging guide passage as a scavenging port opened on the upper surface of the piston, it flows toward the cylinder head through the central part in the cylinder, so it is suitable for efficiently guiding scavenging gas toward the cylinder head. However, there is a problem that all the exhaust gas generated after the explosive combustion of the scavenging gas cannot be exhausted from the exhaust port, and a part of the exhaust gas remains in the cylinder.

【００１１】また、この方式では、ピストンの上端部に
側面から上面にかけて掃気案内通路としての穴を設ける
ために、穴の分だけピストンの上端面の表面積が増大
し、シリンダヘッドとの間に形成される燃焼室の容積が
大きくなって、シリンダ内の圧縮比が上がらず、穴の中
の掃気ガスも熱がピストンに逃げて充分に燃焼しないの
で燃焼効率もよくはなかった。Further, in this method, since a hole as a scavenging guide passage is provided at the upper end of the piston from the side surface to the upper surface, the surface area of the upper end surface of the piston is increased by the amount of the hole, and the piston is formed between the piston and the cylinder head. The volume of the combustion chamber is large, the compression ratio in the cylinder does not increase, and the scavenging gas in the hole also loses heat to the piston and does not burn sufficiently, so that the combustion efficiency is not good.

【００１２】さらに、前記実開昭５９−２８６２８号に
は、掃気ポートからシリンダ内へ送り込んだ掃気ガスを
シリンダ内で効率よくループ状に流動させる別の手段と
して、ピストンの上端面周縁に平面から見てＶ字形に削
り取られた窪みを設けて、掃気ポートからシリンダ内へ
送り込まれた掃気ガスが、ピストンの上端面周縁のＶ字
形の窪みに案内されて排気ポートと反対側の壁面方向に
流れるようにした掃気方式の構成が開示されている。Furthermore, Japanese Utility Model Application Laid-Open No. 59-28628 discloses another means for efficiently flowing a scavenging gas sent from a scavenging port into a cylinder in a loop shape in a cylinder. A scavenging gas cut into a V-shape is provided, and scavenging gas sent from the scavenging port into the cylinder is guided by the V-shaped recess at the periphery of the upper end surface of the piston and flows toward the wall surface opposite to the exhaust port. A configuration of such a scavenging method is disclosed.

【００１３】しかし、この掃気方式も、掃気ポートから
シリンダ内へ送り込まれた掃気ガスを、Ｖ字形の窪みに
よって強制的に排気ポートと反対側の壁面方向へ案内す
るので、掃気ガスをシリンダ内で効率よくループ状に流
動させることはできるとしても、ピストンの上端面周縁
に設けたＶ字形の窪みの容積分だけ、シリンダヘッドと
の間に形成される燃焼室の容積が大きくなり、シリンダ
内の圧縮比が上がらず、燃焼効率もよくないという問題
点を有している。However, also in this scavenging method, the scavenging gas sent from the scavenging port into the cylinder is forcibly guided toward the wall surface on the side opposite to the exhaust port by the V-shaped recess, so that the scavenging gas is transferred inside the cylinder. Even though the fluid can be efficiently made to flow in a loop, the volume of the combustion chamber formed between the cylinder head and the cylinder head is increased by the volume of the V-shaped recess provided on the peripheral edge of the upper end surface of the piston. There is a problem that the compression ratio does not increase and the combustion efficiency is not good.

【００１４】[0014]

【課題を解決するための手段】本発明は、従来における
上記のような反転掃気式２サイクルエンジンの問題点に
鑑み、クランクケース内からシリンダの掃気ポートへ到
る掃気ガスの掃気通路と、シリンダヘッドの燃焼室とを
改善することにより、掃気ポートから送り込まれる適正
な濃度の掃気ガスをシリンダヘッドの燃焼室内へ効率よ
く流動させて、排気ポートからの素通り漏出をなくし、
燃料消費率の向上と排気ガス中のハイドロカーボンの大
幅な低減を期待できる反転掃気式２サイクルエンジンの
提供を目的としたものである。SUMMARY OF THE INVENTION The present invention has been made in consideration of the above-described problems of the conventional reversing scavenging two-stroke engine, and has a scavenging passage for scavenging gas from a crankcase to a scavenging port of the cylinder. By improving the combustion chamber of the head, scavenging gas of an appropriate concentration sent from the scavenging port is efficiently flown into the combustion chamber of the cylinder head, eliminating leakage through the exhaust port,
It is an object of the present invention to provide a reversible scavenging two-cycle engine that can be expected to improve the fuel consumption rate and greatly reduce the amount of hydrocarbons in exhaust gas.

【００１５】本発明の２サイクルエンジンは、そのため
の具体的手段として、反転掃気式２サイクルエンジンに
おけるクランクケースの掃気通路とシリンダの掃気通路
との間に、掃気ガスをシリンダ掃気通路底部内へ排気方
向と反対側から送り出す水平な放出通路を有し、前記シ
リンダの掃気通路は、前記通路底部の上方に縦向きに設
けた隔壁により、前記放出通路から送り出される掃気ガ
スのうち該通路底部の内奥まで達する質量の大きい燃料
粒子からなる濃い掃気ガスを上方の掃気ポートの方向へ
上昇させる通路と、通路の内奥まで達しない質量の小さ
い燃料粒子からなる薄い掃気ガスを上方の掃気ポートの
方向へ上昇させる通路とに区画されていることを特徴と
する。The two-stroke engine of the present invention, as a specific means for this purpose, discharges scavenging gas into the cylinder scavenging passage bottom between the scavenging passage of the crankcase and the scavenging passage of the cylinder in the reversing scavenging two-cycle engine. A scavenging passage of the cylinder, wherein a scavenging passage of the cylinder is formed by a partition provided vertically above the bottom of the passage, and a scavenging gas sent out of the scavenging gas out of the passage bottom is formed in the passage bottom. A passage that raises the dense scavenging gas composed of large-mass fuel particles reaching the back toward the upper scavenging port, and a thin scavenging gas composed of small-mass fuel particles that do not reach the inside of the passage toward the upper scavenging port. And a passage for ascending.

【００１６】上記の反転掃気式２サイクルエンジンは、
ピストン上端面にＵ字形の凸条が突出するような形状の
ディフレクターが、平面から見てＵ字を構成する２つの
凸条間の開口部がシリンダの排気ポート側に位置するよ
うな向きに設けられている。The above-mentioned reversing scavenging two-stroke engine has the following features:
A deflector shaped such that a U-shaped ridge protrudes from the upper end surface of the piston is provided in such a direction that the opening between the two ridges forming the U-shape is located on the exhaust port side of the cylinder when viewed from above. Have been.

【００１７】また、反転掃気式２サイクルエンジンは、
シリンダヘッドの燃焼室に、前記ピストンのＵ字形ディ
フレクターが嵌め込まれる嵌合部を備えている。Further, the reversing scavenging two-cycle engine is
A fitting portion is provided in the combustion chamber of the cylinder head, in which the U-shaped deflector of the piston is fitted.

【００１８】シリンダに開口する掃気ポートは、掃気ガ
ス中の質量の大きい燃料粒子からなる濃い掃気ガスと質
量の小さい燃料粒子からなる薄い掃気ガスとを排気ポー
トの反対側のシリンダ壁面方向へ放出するための、Ｕ字
形ディフレクターの凸条とほぼ平行な向きをもつた隔壁
により仕切られるような構成とすることが好ましい。The scavenging port opening to the cylinder discharges a dense scavenging gas composed of large-mass fuel particles and a thin scavenging gas composed of small-mass fuel particles in the scavenging gas toward the cylinder wall surface opposite to the exhaust port. For this purpose, it is preferable to adopt a configuration in which the partition is separated by a partition wall having a direction substantially parallel to the ridge of the U-shaped deflector.

【００１９】クランクケース内の掃気ガスをクランクケ
ースの掃気通路からシリンダの掃気通路に導入するため
の水平な放出通路と、前記シリンダの掃気通路の底部と
は、クランクケースの上面に設けられた凹溝により一連
に形成されていて、該掃気通路底部の上方にシリンダの
掃気通路が連続して形成されているような構成とするこ
とが好ましい。A horizontal discharge passage for introducing scavenging gas in the crankcase from the scavenging passage of the crankcase to the scavenging passage of the cylinder, and a bottom of the scavenging passage of the cylinder are formed by a concave portion provided on an upper surface of the crankcase. It is preferable that the scavenging passage of the cylinder be continuously formed above the bottom of the scavenging passage by a series of grooves.

【００２０】また、クランクケース内の掃気ガスをクラ
ンクケースの掃気通路からシリンダの掃気通路に導入す
るための放出通路の断面積は、シリンダの掃気通路の断
面積の１／１０〜１／２０であることが好ましく、さら
に、シリンダの掃気通路を二つの通路に区画する縦向き
の隔壁の下端が、クランクケースの上面に接続するシリ
ンダの取付け面とほぼ同一高さ位置に設定されているこ
とが好ましい。The cross-sectional area of the discharge passage for introducing scavenging gas in the crankcase from the scavenging passage of the crankcase to the scavenging passage of the cylinder is 1/10 to 1/20 of the cross-sectional area of the scavenging passage of the cylinder. It is preferable that the lower end of the vertical partition that divides the scavenging passage of the cylinder into two passages is set at substantially the same height as the mounting surface of the cylinder connected to the upper surface of the crankcase. preferable.

【００２１】ディフレクターを形成するＵ字形の凸条
は、高さが排気ポートの高さの１／２程度で、内外両側
面がピストンの上端面に対してほぼ垂直な壁面を形成す
るように断面が正方形または縦長の長方形であることが
好ましい。The U-shaped ridge forming the deflector has a cross section such that the height thereof is about の of the height of the exhaust port, and both inner and outer side surfaces form a wall surface substantially perpendicular to the upper end surface of the piston. Is preferably a square or a vertically long rectangle.

【００２２】シリンダヘッドの燃焼室は、ピストン上端
面におけるＵ字形ディフレクターの嵌め込まれる嵌合部
と、この嵌合部の上方に設けられたシリンダの吸気側壁
面方向から斜め上方に延びる傾斜面及びシリンダの排気
側壁面の上方に位置する垂直面をもった点火プラグ装着
孔と接続する掃気ガス導入凹部とかにより構成すること
が好ましい。The combustion chamber of the cylinder head has a fitting portion on the upper end surface of the piston in which the U-shaped deflector is fitted, an inclined surface extending obliquely upward from the direction of the intake side wall surface of the cylinder provided above the fitting portion. And a scavenging gas introduction recess connected to an ignition plug mounting hole having a vertical surface located above the exhaust side wall surface.

【００２３】[0023]

【発明の実施の形態】本発明に係る２サイクルエンジン
の構成を、図面に示す実施例について説明すると、この
エンジンは、図１に示すように、シリンダ１に混合気を
吸入する吸気ポート３と、燃料ガスを排出する排気ポー
ト４とを有し、ピストン２が上昇した段階で吸気ポート
３からシリンダ１内へ導入された混合気（掃気ガス）
は、クランクケース７の室６内へ送り込まれて、下降す
るピストン２によってクランクケース室６内で圧縮され
る。DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The structure of a two-stroke engine according to the present invention will be described with reference to an embodiment shown in the drawings. As shown in FIG. And an exhaust port 4 for discharging fuel gas, and a mixture (scavenging gas) introduced into the cylinder 1 from the intake port 3 when the piston 2 rises.
Is sent into the chamber 6 of the crankcase 7 and is compressed in the crankcase chamber 6 by the descending piston 2.

【００２４】クランクケース７には、一方の側壁面内に
クランク室６の底部から上方に延びる縦向きの掃気通路
８が設けられていると共に、クランクケース７の上端面
には前記縦向き掃気通路８の上端と接続する水平の掃気
通路９が設けられている。また、シリンダ１には、図７
に示すように、クランクケース７の前記水平の掃気通路
９と通ずる位置からシリンダ１の両側壁面内を通って上
方へ垂直に延びるような掃気通路１０が設けられてい
て、これらの掃気通路８，９，１０の上端が前記シリン
ダ１の両側壁面に開口した掃気ポート５に通じている。A vertical scavenging passage 8 extending upward from the bottom of the crank chamber 6 is provided in one side wall surface of the crankcase 7, and the vertical scavenging passage 8 is provided at an upper end surface of the crankcase 7. A horizontal scavenging passage 9 connected to the upper end of 8 is provided. FIG. 7 shows the cylinder 1.
As shown in FIG. 2, a scavenging passage 10 is provided which extends vertically upward from the position communicating with the horizontal scavenging passage 9 of the crankcase 7 through the inside of both side wall surfaces of the cylinder 1. The upper ends of 9 and 10 communicate with scavenging ports 5 opened on both side walls of the cylinder 1.

【００２５】クランクケース７の側壁面内に設けられる
前記縦向き掃気通路８は、図６に示すように、クランク
ケース７を構成する一対の対称的なケース部材７ａ，７
ｂの縦方向に沿った接合面に、クランク室６の底部から
上方へ延びるように設けた対称的な一対の凹溝８ａ，８
ｂによって形成されている。As shown in FIG. 6, the vertical scavenging passage 8 provided in the side wall surface of the crankcase 7 has a pair of symmetric case members 7a, 7a constituting the crankcase 7.
b, a pair of symmetrical grooves 8a, 8 provided on the joint surface along the longitudinal direction of b to extend upward from the bottom of the crank chamber 6.
b.

【００２６】前記縦向き掃気通路８の上端と接続する水
平の掃気通路９は、図６に示すように、シリンダ１の下
端面と接合するクランクケース７の上端面に、クランク
ケース７の両側方向へ分岐するように設けられた一対の
凹溝からなっていて、これらの凹溝の先端部は、シリン
ダ１の吸気ポート３と排気ポート４とを結ぶ中心線Ａ−
Ａとシリンダ１の中心点で直角に交差するＢ−Ｂ線の上
にまで、前記中心線Ａ−Ａとほぼ平行な向きに水平に延
びており、この先端部に、シリンダ１の両側壁面内を通
って上方へ垂直に延びる前記掃気通路１０の下端を形成
する通路底部１０ａと、これらのシリンダ掃気通路底部
１０ａの手前側に該通路底部１０ａの長さ方向と平行な
向きをもつ水平な放出通路１１とが設けられている。As shown in FIG. 6, a horizontal scavenging passage 9 connected to the upper end of the vertical scavenging passage 8 is provided on the upper end surface of the crankcase 7 joined to the lower end surface of the cylinder 1 in the opposite directions of the crankcase 7. And a pair of concave grooves provided so as to branch to a center line A- connecting the intake port 3 and the exhaust port 4 of the cylinder 1.
A extends horizontally in a direction substantially parallel to the center line AA up to a line BB which intersects at right angles at the center point of the cylinder 1, and at the front end thereof, on both side wall surfaces of the cylinder 1. A bottom 10a forming the lower end of the scavenging passage 10 extending vertically upward through the cylinder scavenging passage 10, and a horizontal discharge having a direction parallel to the longitudinal direction of the passage bottom 10a in front of these cylinder scavenging passage bottoms 10a. A passage 11 is provided.

【００２７】更に、図６に示すように、前記シリンダ掃
気通路１０の下端を形成する通路底部１０ａは、その太
さが水平掃気通路９および放出通路１１の太さより大き
く、かつ長さも放出通路１１より大きくなっていて、こ
の掃気通路底部１０ａの手前に設けられる前記放出通路
１１の平面方向からみた断面積が、前記シリンダ掃気通
路底部１０ａの平面方向からみた断面積の１／１０〜１
／２０程度の大きさになっている。Further, as shown in FIG. 6, a passage bottom portion 10a forming the lower end of the cylinder scavenging passage 10 has a thickness larger than that of the horizontal scavenging passage 9 and the discharge passage 11 and has a length larger than that of the discharge passage 11. The cross-sectional area of the discharge passage 11 provided in front of the scavenging passage bottom 10a when viewed from the plane is 1/10 to 1/10 of the cross-sectional area of the cylinder scavenging passage bottom 10a when viewed from the plane.
/ 20 size.

【００２８】また、シリンダ１の両側壁面内を通って上
方へ垂直に延びる前記掃気通路１０は、図７に示すよう
に、クランクケース７の上端面に設けられた一対の凹溝
の先端部における通路底部１０ａの上面と接続する細長
い断面形状の穴が、シリンダ１の両側壁面内に設けられ
ていて、これらの掃気通路１０の先端がシリンダ１の両
側壁面に開口した掃気ポート５に通じている。As shown in FIG. 7, the scavenging passage 10 extending vertically upward through both side wall surfaces of the cylinder 1 is provided at a tip end of a pair of concave grooves provided on an upper end surface of the crankcase 7. Elongated cross-sectional holes connected to the upper surface of the passage bottom 10 a are provided in both side walls of the cylinder 1, and the tips of these scavenging passages 10 communicate with the scavenging ports 5 opened on both side walls of the cylinder 1. .

【００２９】前記の上方へ垂直に延びるシリンダ掃気通
路１０には、長さ方向に沿った中央部に縦向きの隔壁１
２が設けられていて、この隔壁１２の下端はクランクケ
ース７の上面に接続するシリンダ１の下端取付け面とほ
ぼ同一高さ位置、つまり、前記シリンダ掃気通路１０の
下端を形成する通路底部１０ａの上方に位置しており、
一方、前記隔壁１２の上端は前記掃気ポート５にまで達
していて、図２のように、掃気ポート５が隔壁１２によ
り二つの口に区画されている。The vertically extending cylinder scavenging passage 10 has a longitudinally extending partition wall 1 at a central portion along the longitudinal direction.
The lower end of the partition wall 12 is located at substantially the same height as the lower end mounting surface of the cylinder 1 connected to the upper surface of the crankcase 7, that is, the lower end of the passage bottom 10a forming the lower end of the cylinder scavenging passage 10. Located above,
On the other hand, the upper end of the partition wall 12 reaches the scavenging port 5, and the scavenging port 5 is divided into two ports by the partition wall 12, as shown in FIG.

【００３０】また、前記掃気ポート５は、図２に示すよ
うに、開口面が前記隔壁１２により二つの口に区画され
て、前記シリンダ掃気通路１０内より送られてくる掃気
ガス２４を夫々該掃気ポート５から排気ポート４と反対
側の内壁面１３の方向へ放出するようになっている。As shown in FIG. 2, the scavenging port 5 has an opening surface divided into two ports by the partition wall 12, and receives scavenging gas 24 sent from the cylinder scavenging passage 10, respectively. The air is discharged from the scavenging port 5 in the direction of the inner wall surface 13 opposite to the exhaust port 4.

【００３１】図２及び図４に示すように、シリンダ１内
のピストン２の上端面には、前記掃気ポート５から導入
された掃気ガス２４をシリンダ１内の排気ポート４と反
対側の内壁面１３の方向へ送り込むためのディフレクタ
ー１４が設けられている。このディフレクター１４はピ
ストン２の上端面に、平面から見てＵ字形をなすように
突出させた凸条１５からなっていて、Ｕ字を構成する２
つの凸条１５の開口部１５ａがシリンダ１の排気ポート
４側に位置するような向きに設けられている。As shown in FIGS. 2 and 4, on the upper end surface of the piston 2 in the cylinder 1, scavenging gas 24 introduced from the scavenging port 5 is provided on the inner wall surface opposite to the exhaust port 4 in the cylinder 1. A deflector 14 for feeding in the direction of 13 is provided. The deflector 14 is formed on the upper end surface of the piston 2 by a ridge 15 projecting so as to form a U-shape when viewed from a plane.
The openings 15 a of the two ridges 15 are provided in such a direction as to be located on the exhaust port 4 side of the cylinder 1.

【００３２】なお、このディフレクター１４は、Ｕ字を
構成する２つの凸条１５の中間部がＵの字のような大き
な円弧の湾曲面１５ｂにより連結されていると共に、２
つの凸条１５の両端がＶの字のように若干傾斜した形状
であることが好ましい。The deflector 14 has an intermediate portion between two ridges 15 forming a U-shape connected by a large arcuate curved surface 15b like a U-shape.
It is preferable that both ends of the two ridges 15 have a shape slightly inclined like a V-shape.

【００３３】ピストン２の３端面は、このディフレクタ
ー１４が設けられることで、Ｕ字を構成する２つの凸条
１５によって囲まれた内側エリア１６ａと２つの凸条１
５の外側エリア１６ｂとに区画される。The three end faces of the piston 2 are provided with the deflector 14 so that the inner area 16a surrounded by the two ridges 15 forming a U-shape and the two ridges 1
5 outside area 16b.

【００３４】Ｕ字形のディフレクター１４を形成する前
記凸条１５は、内外両側面がピストン２の上端面に対し
てほぼ垂直な壁面を形成するように、断面が正方形また
は縦長の長方形になっている。図４に示すように、前記
凸条１５は、その高さ１５ｈが排気ポート４の縦方向の
長さ４ｈの１／２程度であることが好ましい。The ridges 15 forming the U-shaped deflector 14 have a square or vertically long rectangular cross section so that both inner and outer side surfaces form a wall surface substantially perpendicular to the upper end surface of the piston 2. . As shown in FIG. 4, it is preferable that the height 15 h of the ridge 15 is about 程度 of the vertical length 4 h of the exhaust port 4.

【００３５】また、前記凸条１５はＵ字を構成する２つ
の凸条１５の外側面が、いずれも図２の矢印に示すよう
に、掃気ポート５から導入される掃気ガス２４の流路の
内側に配置されて、導入される掃気ガス２４が夫々の凸
条１５に沿って外側エリア１６ｂの上を流れながらシリ
ンダ１内の排気ポート４と反対側の内壁面１３の方向へ
案内されるようになっている。As shown by arrows in FIG. 2, each of the ridges 15 has an outer surface of the two ridges 15 constituting a U-shape, as shown by arrows in FIG. Arranged on the inside, the scavenging gas 24 to be introduced is guided in the direction of the inner wall surface 13 opposite to the exhaust port 4 in the cylinder 1 while flowing over the outer area 16b along the respective ridges 15. It has become.

【００３６】一方、前記ディフレクター１４を設けたピ
ストン２の上端面と対向するシリンダヘッド１７には、
ピストン２の上端面の前記ディフレクター１４と、この
ディフレクター１４の２つの凸条１５によって囲まれた
内側エリア１６ａとが嵌まり込む形状の燃焼室１８と、
ディフレクター１４の外側エリア１６ｂのピストン上端
面とが当接する天井面１９とを有している。On the other hand, a cylinder head 17 facing the upper end surface of the piston 2 provided with the deflector 14 is provided with:
A combustion chamber 18 having a shape into which the deflector 14 on the upper end surface of the piston 2 and an inner area 16a surrounded by the two ridges 15 of the deflector 14 are fitted;
It has a ceiling surface 19 with which the piston upper end surface of the outer area 16b of the deflector 14 abuts.

【００３７】図１及び図４に示すように、前記燃焼室１
８は、該燃焼室１８の内周面においてディフレクター１
４の外側面と上面との形状に適合し、ディフレクター１
４の内側エリア１６ａを内側に嵌め込む嵌合部１８ａ
と、この嵌合部１８ａの上方にシリンダ１の排気ポート
４と反対側の内壁面１３方向から斜め上方に延びるよう
に設けられた傾斜面２１及びシリンダ１の排気ポート４
側の内壁面の上方に位置する垂直面２２をもった掃気ガ
ス導入凹部２０とからなっている。As shown in FIGS. 1 and 4, the combustion chamber 1
8 is a deflector 1 on the inner peripheral surface of the combustion chamber 18.
4 conforms to the shape of the outer surface and the upper surface, and the deflector 1
The fitting portion 18a which fits the inside area 16a of the inside 4 inside.
And an inclined surface 21 provided above the fitting portion 18a so as to extend obliquely upward from the direction of the inner wall surface 13 opposite to the exhaust port 4 of the cylinder 1 and the exhaust port 4 of the cylinder 1.
And a scavenging gas introduction recess 20 having a vertical surface 22 located above the inner wall surface on the side.

【００３８】燃焼室１８の上端に取り付けられる点火プ
ラグ２３は、その軸線方向がシリンダ１の排気ポート４
と反対側の内壁面１３方向から、前記傾斜面２１に沿っ
て流動してくる掃気ガス２４と対向するような方向へ傾
斜して設けられていて、点火位置が前記ピストン２のデ
ィフレクター１４により囲まれた内側エリア１６ａの中
心部分に対応するように取り付けられている。The ignition plug 23 attached to the upper end of the combustion chamber 18 has an axial direction
From the direction of the inner wall surface 13 on the opposite side to the direction facing the scavenging gas 24 flowing along the inclined surface 21, and the ignition position is surrounded by the deflector 14 of the piston 2. It is attached so as to correspond to the central portion of the inside area 16a.

【００３９】吸気ポート３から吸い込まれた混合気（掃
気ガス）は、ピストン２の下降により生ずるクランク室
６内の圧力によってクランクケース７の細い掃気通路８
から上方の水平掃気通路９に向けて送られる。前記掃気
通路８を通過する掃気ガス２４はクランクケース７の熱
で暖められて一部が気化してガス化されるが、その態様
は実質的に気体というよりは、液体燃料の粒子と空気の
混合物である飛沫（ミスト）の状態、つまり未だ液体の
粒子が多い状態である。The air-fuel mixture (scavenging gas) sucked from the intake port 3 is supplied to the narrow scavenging passage 8 of the crankcase 7 by the pressure in the crank chamber 6 caused by the lowering of the piston 2.
To the horizontal scavenging passage 9 above. The scavenging gas 24 passing through the scavenging passage 8 is heated by the heat of the crankcase 7 and partially vaporized to be gasified. In this embodiment, the liquid fuel particles and the air are not substantially gas. It is in the state of a droplet (mist) that is a mixture, that is, a state in which there are still many liquid particles.

【００４０】前記掃気ガス２４は、縦方向の掃気通路８
から上方の水平方向の掃気通路９に入る部分を除けば大
きく曲がる箇所が少ないので、通過する掃気ガス２４
は、図７に示すように、大きな抵抗を受けることなく先
端部分の水平な放出通路１１を通って排気ポート４側か
ら吸気ポート３側の方向へ向けてシリンダ掃気通路底部
１０ａ内へ勢いよく送り込まれたのちシリンダ掃気通路
１０の壁に沿って上昇する。The scavenging gas 24 is transferred to the scavenging passage 8 in the vertical direction.
Except for the part entering the horizontal scavenging passage 9 above, there are few sharp bends, so the scavenging gas 24
As shown in FIG. 7, as shown in FIG. 7, the fuel is rushed into the cylinder scavenging passage bottom 10 a from the exhaust port 4 side toward the intake port 3 side through the horizontal discharge passage 11 at the tip end without receiving a large resistance. After that, it rises along the wall of the cylinder scavenging passage 10.

【００４１】前記放出通路１１は水平でシリンダ掃気通
路底部１０ａよりも細いので、掃気ガス２４は細い放出
通路１１から比較的断面積の広い掃気通路底部１０ａ内
へ勢いよく流入することになり、比較的質量の大きい液
体の粒子が水平方向の運動エネルギーにより対向する通
路内奥の垂直な壁１０ｂ付近まで達し、更に大きな液体
の粒子が壁１０ｂに衝突する。つまり質量の大きい液体
粒子からなる濃い掃気ガス２４ａが排気ポート４側から
遠く離れた通路内奥の壁１０ｂに衝突してからシリンダ
掃気通路１０内を上昇し、図２に示した掃気ポート５の
排気ポート４と遠く離れた口から内壁面１３の方向へ吹
き出される。Since the discharge passage 11 is horizontal and narrower than the cylinder scavenging passage bottom 10a, the scavenging gas 24 flows from the narrow discharge passage 11 into the scavenging passage bottom 10a having a relatively large sectional area. The liquid particles having a large target mass reach the vicinity of the vertical wall 10b deep inside the opposed passage due to the kinetic energy in the horizontal direction, and the larger liquid particles collide with the wall 10b. In other words, the dense scavenging gas 24a composed of large liquid particles collides with the inner wall 10b far away from the exhaust port 4 side, and then rises in the cylinder scavenging passage 10, and the scavenging port 5 shown in FIG. It is blown out from the port far away from the exhaust port 4 in the direction of the inner wall surface 13.

【００４２】一方、放出通路１１から送り出される掃気
ガス２４のうち、比較的質量の小さい液体の粒子とガス
化した掃気ガス、つまり質量の小さい液体粒子からなる
薄い掃気ガス２４ｂは、運動エネルギーが小さいので通
路内奥の垂直な壁１０ｂにまで達することができず、シ
リンダ掃気通路１０内の排気ポート４に近い側の部分を
縦向きの隔壁１２に沿って上昇し、図２に示した掃気ポ
ート５の排気ポート４に近い側の口からシリンダ１内へ
送り出される。縦向きの隔壁１２の下端がシリンダ掃気
通路底部１０ａの上方に位置していることは、質量の小
さい薄い掃気ガス２４ｂを上方の掃気ポート５の方向へ
案内することに役立つ。On the other hand, of the scavenging gas 24 sent out from the discharge passage 11, the thin scavenging gas 24b composed of relatively small-mass liquid particles and gasified scavenging gas, that is, small-mass liquid particles, has small kinetic energy. Therefore, the scavenging port shown in FIG. 2 cannot rise to the vertical wall 10b deep inside the passage, but rises along the vertical partition 12 in the portion near the exhaust port 4 in the cylinder scavenging passage 10. 5 is discharged into the cylinder 1 from the port near the exhaust port 4. The fact that the lower end of the vertical partition wall 12 is located above the cylinder scavenging passage bottom 10 a helps to guide the thin mass scavenging gas 24 b toward the scavenging port 5 above.

【００４３】掃気ポート５は、図２に示すように、開口
面がＵ字形ディフレクターの凸条１５とほぼ平行な向き
に傾斜する隔壁１２により二つに仕切られているので、
シリンダ掃気通路１０内より送られてくる掃気ガス２４
ａ，２４ｂを該掃気ポート５から排気ポート４と反対側
の内壁面１３の方向へ送り出す。As shown in FIG. 2, the scavenging port 5 is divided into two by a partition wall 12 whose opening surface is inclined in a direction substantially parallel to the ridge 15 of the U-shaped deflector.
Scavenging gas 24 sent from the cylinder scavenging passage 10
a and 24b are sent from the scavenging port 5 in the direction of the inner wall surface 13 opposite to the exhaust port 4.

【００４４】掃気ポート５から送り出された掃気ガス２
４ａ，２４ｂは、ピストン２の上端のディフレクターの
凸条１５の外側面にぶつかって、該凸条１５の内側エリ
ア１６ａ方向への流入を阻止され、外側エリア１６ｂの
上を流れながらシリンダ１内の排気ポート４と反対側の
内壁面１３の方向へ案内されてからシリンダヘッドの方
向へ流れる。Scavenging gas 2 sent out from scavenging port 5
4a and 24b hit against the outer surface of the ridge 15 of the deflector at the upper end of the piston 2 and are prevented from flowing in the direction of the inner area 16a of the ridge 15, and flow inside the cylinder 1 while flowing on the outer area 16b. It is guided in the direction of the inner wall surface 13 opposite to the exhaust port 4 and then flows in the direction of the cylinder head.

【００４５】そのためシリンダ１内の掃気ガス２４ａ，
２４ｂは、掃気ポート５から排気ポート４の方向へ直接
素通りして外部へ漏出することが抑えられて、シリンダ
１内の排気ポート４と反対側の内壁面１３に沿ってルー
プ状に流れる層だけが形成され、シリンダ１内の中心部
方向への流れも発生しないので、燃焼される前に排気ポ
ート４へ素通りして外部へ漏出する未燃ガスの量を大幅
に抑制することができる。Therefore, the scavenging gas 24a,
24b is only a layer which is prevented from leaking to the outside through the scavenging port 5 in the direction of the exhaust port 4 and directly flowing in a loop along the inner wall surface 13 opposite to the exhaust port 4 in the cylinder 1. Is formed, and no flow toward the central portion in the cylinder 1 is generated, so that the amount of unburned gas leaking to the outside through the exhaust port 4 before burning can be greatly reduced.

【００４６】燃焼室１８は、ディフレクター１４の外側
面と上面との形状に適合し、ディフレクター１４の内側
エリア１６ａを内側に嵌め込む嵌合部１８ａと、この嵌
合部１８ａの上方にシリンダ１の排気ポート４と反対側
の内壁面１３方向から斜め上方に延びるような傾斜面２
１をもった掃気ガス導入凹部２０とからなっているの
で、内壁面１３に沿って上昇する掃気ガス２４が流れ込
み易く、流れ込んだ掃気ガス２４を点火プラグ２３の下
面で確実に捕捉して燃焼することができる。The combustion chamber 18 has a fitting portion 18a which fits the shape of the outer surface and the upper surface of the deflector 14 and fits the inner area 16a of the deflector 14 inside, and the cylinder 1 above the fitting portion 18a. Inclined surface 2 extending obliquely upward from the direction of inner wall surface 13 opposite to exhaust port 4
Since the scavenging gas introduction recess 20 having the shape 1 is provided, the scavenging gas 24 rising along the inner wall surface 13 easily flows in, and the scavenging gas 24 that has flowed in is reliably captured by the lower surface of the ignition plug 23 and burned. be able to.

【００４７】また、掃気ガス導入凹部２０にはシリンダ
１の排気ポート４側の内壁面の上方に垂直面２２を有し
ているので、流れ込まれる掃気ガス２４の運動エネルギ
ーを点火プラグ２３の下面で減少すると共に、掃気ガス
２４が爆発燃焼したのちに発生する排気ガスを次に送り
込まれる掃気ガス２４によって、下方の排気ポート４の
方向へ効率よく案内するように押し出して適切に排気す
る。また、送り込まれる掃気ガス２４は、掃気ガス導入
凹部２０で運動エネルギーを減少して速度を落とされる
ので、送り込まれた掃気ガス自体が排気ポート４から出
てしまうことを抑制することができる。Since the scavenging gas introduction recess 20 has a vertical surface 22 above the inner wall surface on the exhaust port 4 side of the cylinder 1, the kinetic energy of the scavenging gas 24 flowing into the scavenging gas 24 is reduced by the lower surface of the spark plug 23. The exhaust gas generated after the scavenging gas 24 explodes and combusts is pushed out by the scavenging gas 24 to be sent next so as to be efficiently guided toward the lower exhaust port 4 and is appropriately exhausted. Further, the scavenging gas 24 to be sent is reduced in kinetic energy by the scavenging gas introduction recess 20 and its speed is reduced, so that the sent scavenging gas itself can be suppressed from coming out of the exhaust port 4.

【００４８】[0048]

【発明の効果】上記のように、本発明の２サイクルエン
ジンでは、クランクケース７内に導入された掃気ガス２
４を、上方の水平掃気通路９における細い放出通路１１
を通して排気ポート４側からシリンダ掃気通路１０の底
部１０ａ内へ勢いよく噴出すことで、同じ速度で水平に
移動する燃料粒子と空気の混合物は、粒子の大きさによ
り到達できる距離が異なることを利用して、質量の大き
い粒子からなる濃い掃気ガス２４ａはシリンダ掃気通路
１０の内奥の壁１０ｂにまで達した位置で該通路内を上
昇させ、質量の小さい粒子からなる薄い掃気ガス２４ｂ
はシリンダ掃気通路１０の内奥の壁１０ｂにまで達しな
い位置で該通路内を上昇させることができる。As described above, in the two-stroke engine of the present invention, the scavenging gas 2 introduced into the crankcase 7
4 to the narrow discharge passage 11 in the upper horizontal transfer passage 9
Through the exhaust port 4 side into the bottom 10a of the cylinder scavenging passage 10 through the exhaust port 4 so that the mixture of fuel particles and air moving horizontally at the same speed can reach different distances depending on the size of the particles. The dense scavenging gas 24a composed of particles having a large mass rises in the cylinder scavenging passage 10 at a position reaching the inner wall 10b of the cylinder scavenging passage 10, and the thin scavenging gas 24b composed of particles having a small mass is removed.
Can be raised in the cylinder scavenging passage 10 at a position that does not reach the inner wall 10b.

【００４９】その結果、掃気ガス２４は濃淡に分離さ
れ、質量の大きい粒子からなる濃い掃気ガス２４ａを、
排気ポート４から遠く離れた位置から掃気通路壁１０ｂ
に沿って上方の掃気ポート５より直接シリンダ１内の排
気ポート４と反対側の内壁面１３の方向へ案内すること
ができ、また、質量の小さい粒子からなる薄い掃気ガス
２４ｂは、排気ポート４に近い位置から隔壁１２に沿っ
て上方の掃気ポート５より放出された位置でディフレク
ター１４の凸条１５によって前記内壁面１３の方向へ案
内されるので、濃い掃気ガス２４ａはもとより薄い掃気
ガス２４ｂも排気ポート４と反対側の内壁面１３の方向
へ案内でき、未燃ガスが掃気ポート５から排気ポート４
の方向へ素通りして漏出する現象を防止し、有効な掃気
作用を果たすことができる。As a result, the scavenging gas 24 is separated into dark and light, and the dense scavenging gas 24a composed of large mass particles is
Scavenging passage wall 10b from a position far from exhaust port 4
Can be guided directly from the upper scavenging port 5 toward the inner wall surface 13 on the opposite side of the exhaust port 4 in the cylinder 1, and the thin scavenging gas 24 b composed of particles having a small mass is discharged from the exhaust port 4. Is guided toward the inner wall surface 13 by the ridge 15 of the deflector 14 at a position discharged from the upper scavenging port 5 along the partition wall 12 from a position close to the partition wall 12, so that not only the thick scavenging gas 24a but also the thin scavenging gas 24b The unburned gas can be guided from the scavenging port 5 to the exhaust port 4 in the direction of the inner wall 13 opposite to the exhaust port 4.
The phenomenon of leaking out in the direction of 素 can be prevented, and an effective scavenging action can be achieved.

【００５０】なお、上記掃気ポート５からシリンダ１内
へ送り込まれる掃気ガスのうち、排気ポート４に近い側
から送り込まれる掃気ガスの一部が、掃気ポート５から
出た直後に排気ポート４へ素通りしてしまうことがあっ
たとしても、本発明では、掃気ガス２４を予め掃気ポー
ト５の手前の掃気通路１０で、質量の大きい粒子からな
る濃い掃気ガス２４ａと質量の小さい粒子からなる薄い
掃気ガス２４ｂとに分離しているので、前記のように掃
気ポート５の排気ポート４に近い側から送り込まれた直
後に排気ポート４へ素通りしてしまうような掃気ガス
は、質量の小さい粒子からなる薄い掃気ガス２４ｂであ
るため、排気ガス中のハイドロカーボン（ＨＣ）の濃度
に対する影響をきわめて少なくすることができる。勿
論、質量の大きい粒子からなる濃い掃気ガス２４ａは、
排気ポート４から遠い側から送り出されるので排気ポー
ト４へ素通りすることはない。Note that, of the scavenging gas sent from the scavenging port 5 into the cylinder 1, a part of the scavenging gas sent from the side near the exhaust port 4 passes through the exhaust port 4 immediately after leaving the scavenging port 5. However, in the present invention, the scavenging gas 24 is supplied to the scavenging passage 10 in front of the scavenging port 5 in advance by the scavenging gas 24a composed of large particles and the thin scavenging gas composed of small particles. 24b, the scavenging gas which passes through the exhaust port 4 immediately after being sent from the side of the scavenging port 5 close to the exhaust port 4 as described above is a thin gas consisting of small particles. Because of the scavenging gas 24b, the influence on the concentration of hydrocarbon (HC) in the exhaust gas can be extremely reduced. Of course, the dense scavenging gas 24a composed of large particles is
Since the air is sent out from the side far from the exhaust port 4, it does not pass through to the exhaust port 4.

【００５１】また、シリンダヘッド１７には、ピストン
上端面のディフレクター１４の外側エリア１６ｂが当接
する天井面１９と、ディフレクター１４の凸条１５によ
って囲まれた内側エリア１６ａとが嵌まり込む形状の燃
焼室１８とを有しているので、ピストン２が上昇する
と、排気ポート４と反対側の内壁面１３方向から流入す
る掃気ガス２４を、上方の燃焼室１８内へ押し込むよう
なタービュレンスを与えるスキッシュゾーンが形成さ
れ、、次いでディフレクター１４が燃焼室１８内に嵌ま
り込むことによって、ディフレクター１４の外側面と燃
焼室１８の内周縁とが無駄なく嵌合し、掃気ガス２４を
燃焼室１８とディフレクター１４の内側エリア１６ａと
の間に形成される空間内に確実に閉じ込めて圧縮比を高
めることができ、点火に伴う火炎伝播の距離を短くし
て、燃焼効率を良好にし、高い出力を得ることができ
る。Further, the cylinder head 17 has a combustion surface having a shape in which a ceiling surface 19 at which the outer area 16b of the deflector 14 at the upper end face of the piston abuts and an inner area 16a surrounded by the protruding ridge 15 of the deflector 14 are fitted. When the piston 2 rises, the scavenging gas 24 flowing from the direction of the inner wall surface 13 opposite to the exhaust port 4 is squished to give turbulence to push the scavenging gas 24 into the upper combustion chamber 18. A zone is formed, and then the deflector 14 is fitted into the combustion chamber 18 so that the outer surface of the deflector 14 and the inner periphery of the combustion chamber 18 are fitted without waste, and the scavenging gas 24 is transferred to the combustion chamber 18 and the deflector. 14 can be reliably confined in the space formed between it and the inner area 16a to increase the compression ratio. By shortening the distance of flame propagation caused by improving the combustion efficiency, it is possible to obtain a high output.

【００５２】本発明の２サイクルエンジンでは、上記の
ように、従来の反転掃気式２サイクルエンジンの欠点と
されていた掃気ガスの排気ポートへの素通りによる漏出
を確実に防止して、燃料室での燃焼効率を高めることが
できるので、排気ガス中のハイドロカーボン（ＨＣ）成
分を５０％以上減少することができるだけでなく、燃料
消費率も３０％減少することができた。In the two-stroke engine of the present invention, as described above, the leakage of the scavenging gas through the exhaust port, which is a drawback of the conventional reversing scavenging two-stroke engine, is surely prevented, and the two-stroke engine is disposed in the fuel chamber. Since the combustion efficiency of the fuel can be increased, not only the hydrocarbon (HC) component in the exhaust gas can be reduced by 50% or more, but also the fuel consumption rate can be reduced by 30%.

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

【図１】本発明に係る２サイクルエンジンのピストン上
昇時における全体縦断面図。FIG. 1 is an overall longitudinal sectional view of a two-stroke engine according to the present invention when a piston is raised.

【図２】図１のＩＩ−ＩＩ線における断面図。FIG. 2 is a sectional view taken along line II-II in FIG.

【図３】ピストンヘッドに設けられるディフレクターの
形状を示すピストンの斜視図。FIG. 3 is a perspective view of a piston showing a shape of a deflector provided in the piston head.

【図４】掃気ポートから送り出される掃気ガスの、シリ
ンダ内における流れの方向を示すシリンダの縦断面図。FIG. 4 is a longitudinal sectional view of the cylinder showing a flow direction of scavenging gas sent from a scavenging port in the cylinder.

【図５】図１のＶ−Ｖ線における断面図。FIG. 5 is a sectional view taken along line VV in FIG. 1;

【図６】図１のＶＩ−ＶＩ線における断面図。FIG. 6 is a sectional view taken along line VI-VI in FIG. 1;

【図７】クランクケースとシリンダとの間の掃気通路の
形状を示す部分拡大縦断面図。FIG. 7 is a partially enlarged longitudinal sectional view showing a shape of a scavenging passage between a crankcase and a cylinder.

【符号の説明】[Explanation of symbols]

１：シリンダ ２：ピストン ３：吸気ポート ４：排気ポート ５：掃気ポート ６：クランクケース室 ７：クランクケース ８：クランク掃気通路 ９：水平掃気通路 １０：シリンダ掃気通路 １０ａ：シリンダ掃気通路底部 １１：放出通路 １２：隔壁 １３：シリンダ内壁面 １４：ディフレクター １５：凸条 １６ａ：内側エリア １６ｂ：外側エリア １７：シリンダヘッド １８：燃焼室 １８ａ：嵌合部 １９：天井面 ２０：掃気ガス導入凹部 ２１：傾斜面 ２２：垂直面 ２３：点火プラグ ２４：掃気ガス 1: Cylinder 2: Piston 3: Intake port 4: Exhaust port 5: Scavenging port 6: Crankcase chamber 7: Crankcase 8: Crank scavenging passage 9: Horizontal scavenging passage 10: Cylinder scavenging passage 10a: Cylinder scavenging passage bottom 11: Release passage 12: Partition wall 13: Cylinder inner wall surface 14: Deflector 15: Convex 16a: Inner area 16b: Outer area 17: Cylinder head 18: Combustion chamber 18a: Fitting portion 19: Ceiling surface 20: Scavenging gas introduction recess 21: Inclined surface 22: Vertical surface 23: Spark plug 24: Scavenging gas

───────────────────────────────────────────────────── フロントページの続き (51)Int.Cl.6 識別記号 ＦＩ Ｆ０２Ｆ 3/24 Ｆ０２Ｆ 3/24 ──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. 6 Identification code FI F02F 3/24 F02F 3/24

Claims (9)

【特許請求の範囲】[Claims] 【請求項１】 反転掃気式２サイクルエンジンにおける
クランクケースの掃気通路とシリンダの掃気通路との間
に、掃気ガスをシリンダ掃気通路底部内へ排気方向と反
対側から送り出す水平な放出通路を有し、前記シリンダ
の掃気通路は、前記通路底部の上方に縦向きに設けた隔
壁により、前記放出通路から送り出される掃気ガスのう
ち該通路底部の内奥まで達する質量の大きい燃料粒子か
らなる濃い掃気ガスを上方の掃気ポートの方向へ上昇さ
せる通路と、通路の内奥まで達しない質量の小さい燃料
粒子からなる薄い掃気ガスを上方の掃気ポートの方向へ
上昇させる通路とに区画されていることを特徴とする２
サイクルエンジン。1. A horizontal discharge passage for discharging scavenging gas into a bottom of a cylinder scavenging passage from a side opposite to an exhaust direction between a scavenging passage of a crankcase and a scavenging passage of a cylinder in a reversing scavenging two-cycle engine. The scavenging passage of the cylinder is a scavenging gas composed of fuel particles having a large mass reaching the inside of the bottom of the passage, out of the scavenging gas sent out from the discharge passage by a partition wall provided vertically above the bottom of the passage. And a passage for raising thin scavenging gas composed of fuel particles having a small mass that does not reach the inside of the passage toward the upper scavenging port. 2
Cycle engine. 【請求項２】 反転掃気式２サイクルエンジンのピスト
ン上端面に、Ｕ字形の凸条が突出するような形状のディ
フレクターを、平面から見てＵ字を構成する２つの凸条
間の開口部がシリンダの排気ポート側に位置するような
向きに設けたことを特徴とする２サイクルエンジン。2. A deflector having a shape such that a U-shaped ridge protrudes from an upper end surface of a piston of a reversing scavenging two-stroke engine, and an opening between two ridges forming a U-shape when viewed from a plane. A two-stroke engine characterized by being provided so as to be located on an exhaust port side of a cylinder. 【請求項３】 シリンダヘッドの燃焼室に、前記ピスト
ンのＵ字形ディフレクターが嵌め込まれる嵌合部を備え
ていることを特徴とする２サイクルエンジン。3. The two-stroke engine according to claim 1, further comprising a fitting portion into which a U-shaped deflector of said piston is fitted in a combustion chamber of a cylinder head. 【請求項４】 シリンダに開口する掃気ポートが、質量
の大きい燃料粒子からなる濃い掃気ガスと質量の小さい
燃料粒子からなる薄い掃気ガスとを排気ポートの反対側
のシリンダ内壁面方向へ放出するための隔壁により仕切
られている請求項１の２サイクルエンジン。4. A scavenging port opened to a cylinder for discharging a dense scavenging gas composed of large-mass fuel particles and a thin scavenging gas composed of small-mass fuel particles toward a cylinder inner wall surface opposite to the exhaust port. 2. The two-stroke engine according to claim 1, wherein said two-stroke engine is partitioned by said partition wall. 【請求項５】 クランクケース内の掃気ガスをクランク
ケースの掃気通路からシリンダの掃気通路に導入するた
めの放出通路と、前記シリンダの掃気通路の底部とが、
クランクケースの上面に設けられた凹溝により一連に形
成されており、該掃気通路底部の上方にシリンダの掃気
通路が連続して形成されている請求項１の２サイクルエ
ンジン。5. A discharge passage for introducing scavenging gas in a crankcase from a scavenging passage of a crankcase to a scavenging passage of a cylinder, and a bottom portion of the scavenging passage of the cylinder,
2. The two-stroke engine according to claim 1, wherein the two-stroke engine is formed by a series of concave grooves provided on the upper surface of the crankcase, and the scavenging passage of the cylinder is continuously formed above the bottom of the scavenging passage. 【請求項６】 クランクケース内の掃気ガスをクランク
ケースの掃気通路からシリンダの掃気通路に導入するた
めの放出通路の断面積が、シリンダの掃気通路の断面積
の１／１０〜１／２０である請求項１の２サイクルエン
ジン。6. A cross-sectional area of a discharge passage for introducing scavenging gas in the crankcase from a scavenging passage of the crankcase to a scavenging passage of the cylinder is 1/10 to 1/20 of a cross-sectional area of the scavenging passage of the cylinder. The two-stroke engine of claim 1. 【請求項７】 シリンダの掃気通路を二つの通路に区画
する隔壁の下端が、クランクケースの上面に接続するシ
リンダの取付け面とほぼ同一高さ位置に設定されている
請求項１の２サイクルエンジン。7. The two-stroke engine according to claim 1, wherein the lower end of the partition partitioning the scavenging passage of the cylinder into two passages is set at substantially the same height as the mounting surface of the cylinder connected to the upper surface of the crankcase. . 【請求項８】 ディフレクターを形成するＵ字形の凸条
は、高さが排気ポートの高さの１／２程度で、内外両側
面がピストンの上端面に対してほぼ垂直な壁面を形成す
るように断面が正方形または縦長の長方形である請求項
２の２サイクルエンジン。8. The U-shaped ridge forming the deflector has a height of about の of the height of the exhaust port, and both inner and outer side surfaces form a wall surface substantially perpendicular to the upper end surface of the piston. 3. The two-stroke engine according to claim 2, wherein the cross section is a square or a vertically long rectangle. 【請求項９】 シリンダヘッドの燃焼室が、ピストン上
端面におけるＵ字形ディフレクターの嵌め込まれる嵌合
部と、この嵌合部の上方に設けられたシリンダの吸気側
壁面方向から斜め上方に延びる傾斜面及びシリンダの排
気側壁面の上方に位置する垂直面をもった点火プラグ装
着孔と接続する掃気ガス導入凹部とからなっている請求
項３の２サイクルエンジン。9. The combustion chamber of the cylinder head has a fitting portion at the upper end surface of the piston in which the U-shaped deflector is fitted, and an inclined surface extending obliquely upward from the direction of the intake side wall surface of the cylinder provided above the fitting portion. 4. The two-stroke engine according to claim 3, further comprising a scavenging gas introduction recess connected to an ignition plug mounting hole having a vertical surface located above the exhaust side wall surface of the cylinder.
JP13419398A 1998-04-30 1998-04-30 2 cycle engine Expired - Fee Related JP3404288B2 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP13419398A JP3404288B2 (en) 1998-04-30 1998-04-30 2 cycle engine

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP13419398A JP3404288B2 (en) 1998-04-30 1998-04-30 2 cycle engine

Publications (2)

Publication Number Publication Date
JPH11315722A true JPH11315722A (en) 1999-11-16
JP3404288B2 JP3404288B2 (en) 2003-05-06

Family

ID=15122618

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* Cited by examiner, † Cited by third party
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FR2840023A1 (en) * 2002-05-24 2003-11-28 Stihl Ag & Co Kg Andreas Two-stroke motor for a hand-held tool such as a power saw or brush cutter comprises transfer ports connected to an air duct at different times during operation of the motor
JP2007309128A (en) * 2006-05-16 2007-11-29 Tanaka Kogyo Kk Stratified scavenging 2-cycle engine
WO2009093310A1 (en) * 2008-01-23 2009-07-30 Shindaiwa Corporation Two-stroke engine
CN101839167A (en) * 2009-03-17 2010-09-22 日立工机株式会社 Two stroke engine and the power tool that is equipped with two stroke engine
EP2278137A2 (en) 2009-07-24 2011-01-26 Yamabiko Corporation Two-stroke internal combustion engine
EP2278136A2 (en) 2009-07-24 2011-01-26 Yamabiko Corporation Two-stroke internal combustion engine
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US6895910B2 (en) 2002-05-24 2005-05-24 Andreas Stihl Ag & Co. Kg Two-cycle engine having scavenging
US9816431B2 (en) 2006-05-16 2017-11-14 Hitachi Koki Co., Ltd. Stratified scavenging two-cycle engine
EP2017446A1 (en) * 2006-05-16 2009-01-21 Nikko Tanaka Engineering Co., Ltd. Laminar-scavenging two-cycle engine
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JP2007309128A (en) * 2006-05-16 2007-11-29 Tanaka Kogyo Kk Stratified scavenging 2-cycle engine
EP2378095A1 (en) 2006-05-16 2011-10-19 Hitachi Koki Co., Ltd. Laminar-scavenging two-cycle engine
US8181611B2 (en) 2006-05-16 2012-05-22 Nikko Tanaka Engineering Co., Ltd. Stratified scavenging two-cycle engine
WO2009093310A1 (en) * 2008-01-23 2009-07-30 Shindaiwa Corporation Two-stroke engine
CN101839167A (en) * 2009-03-17 2010-09-22 日立工机株式会社 Two stroke engine and the power tool that is equipped with two stroke engine
JP2010216394A (en) * 2009-03-17 2010-09-30 Hitachi Koki Co Ltd Two-stroke cycle engine and engine work machine equipped with the same
DE102010011726A1 (en) 2009-03-17 2010-12-30 Hitachi Koki Co., Ltd. Two-stroke engine and engine with this two-stroke engine
US8550043B2 (en) 2009-03-17 2013-10-08 Hitachi Koki Co., Ltd. Two-stroke engine and motorized implement equipped with the two-stroke engine
EP2278136A2 (en) 2009-07-24 2011-01-26 Yamabiko Corporation Two-stroke internal combustion engine
US8353262B2 (en) 2009-07-24 2013-01-15 Yamabiko Corporation Two-stroke internal combustion engine
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CN103339355A (en) * 2011-02-03 2013-10-02 富世华智诺株式会社 Stratified scavenging two-stroke engine
WO2012104919A1 (en) * 2011-02-03 2012-08-09 Husqvarna Zenoah Co., Ltd. Stratified scavenging two-stroke engine
JP2014508876A (en) * 2011-02-03 2014-04-10 ハスクバーナ・ゼノア株式会社 Stratified scavenging two-stroke engine
US8833316B2 (en) 2011-02-03 2014-09-16 Husqvarna Zenoah Co., Ltd. Stratified scavenging two-stroke engine
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