JPH04127839U - 2-stroke internal combustion engine - Google Patents
2-stroke internal combustion engineInfo
- Publication number
- JPH04127839U JPH04127839U JP3248291U JP3248291U JPH04127839U JP H04127839 U JPH04127839 U JP H04127839U JP 3248291 U JP3248291 U JP 3248291U JP 3248291 U JP3248291 U JP 3248291U JP H04127839 U JPH04127839 U JP H04127839U
- Authority
- JP
- Japan
- Prior art keywords
- internal combustion
- combustion engine
- piston
- stroke internal
- fresh air
- 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.)
- Withdrawn
Links
- 238000002485 combustion reaction Methods 0.000 title claims abstract description 20
- 230000002000 scavenging effect Effects 0.000 abstract description 6
- 230000000694 effects Effects 0.000 description 2
- 230000006835 compression Effects 0.000 description 1
- 238000007906 compression Methods 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 230000002401 inhibitory effect Effects 0.000 description 1
- 230000000630 rising effect Effects 0.000 description 1
Landscapes
- Combustion Methods Of Internal-Combustion Engines (AREA)
Abstract
(57)【要約】
【目的】 ２サイクル内燃機関において、掃気性向上を
企図する。
【構成】 ピストン１３の上面３１を、吸気弁１８の下
部から排気弁１７の下部に亘り凹状の円筒面の一部の状
態に形成し、新気が押し込まれた際の新気及び排気をピ
ストン１３の上面３１に案内させて縦回りのＵ字状の流
れにし、タンブル流を増加させて排気ガスを確実に排出
し、掃気性向上を図る。
(57) [Summary] [Purpose] To improve the scavenging performance in a two-stroke internal combustion engine. [Structure] The upper surface 31 of the piston 13 is formed as a part of a concave cylindrical surface extending from the lower part of the intake valve 18 to the lower part of the exhaust valve 17, and when fresh air is pushed in, the fresh air and exhaust gas are transferred to the piston. 13 to form a vertical U-shaped flow, the tumble flow is increased, the exhaust gas is reliably discharged, and the scavenging performance is improved.
Description
【０００１】0001
本考案は２サイクル内燃機関に関し、掃気性の向上を企図したものである。 The present invention relates to a two-stroke internal combustion engine and is intended to improve scavenging performance.
【０００２】0002
シリンダヘッドに吸気（新気）弁及び排気弁を有するオープンチャンバ型２サ イクル内燃機関は、ピストンが下死点にあるときに吸気弁と排気弁とがほぼ同時 に開き、吸気弁から流入した新気は下向きに指向され、ピストン頂面で反転して 、シリンダ内で縦回りのＵ字状の流れを形成するようになっている。新気と排気 の境界面は、最初、吸気弁の近くにあり、次いでシリンダ内の下方中央部になり 、そして排気弁の近くへと移動し、シリンダ内の全体で排気と新気とが置き換わ るようになっている。 Open chamber type 2 cylinder type with intake (fresh air) valve and exhaust valve in the cylinder head. In an internal combustion engine, when the piston is at bottom dead center, the intake valve and exhaust valve open at almost the same time. The fresh air flowing in from the intake valve is directed downward, and is reversed at the top of the piston. , a vertical U-shaped flow is formed within the cylinder. fresh air and exhaust The interface is first near the intake valve and then in the lower middle part of the cylinder. , and moves closer to the exhaust valve, replacing exhaust and fresh air throughout the cylinder. It has become so.
【０００３】0003
従来の２サイクル内燃機関では、ピストンの上面形状が平面となっているので 、縦回りのＵ字状の流れに様々な乱れが生じ、排気と新気の入れ換えが十分に行 なえない場合があった。シリンダ内に多量の排気が残留すると、新気をシリンダ ヘッドの点火プラグの近傍に集めることができず、着火や火炎核の発生が阻害さ れたり、火炎伝播速度の低下による失火が生じる虞があり、燃焼が安定しにくか った。 In conventional two-stroke internal combustion engines, the top surface of the piston is flat. , various turbulence occurs in the vertical U-shaped flow, and sufficient exchange of exhaust air and fresh air occurs. There were times when I couldn't sag. If a large amount of exhaust gas remains in the cylinder, fresh air may be removed from the cylinder. It cannot collect near the spark plug of the head, inhibiting ignition and the generation of a flame kernel. There is a risk of misfire due to a decrease in the flame propagation speed, and combustion may be difficult to stabilize. It was.
【０００４】0004
上記課題を解決するための本考案の構成は、シリンダヘッドに吸気弁及び排気 弁を備えた２サイクル内燃機関において、ピストンの上面を、吸気弁の下部から 排気弁の下部に亘り凹状の円筒面の一部の状態に形成したことを特徴とする。 The structure of the present invention to solve the above problem is that the cylinder head has an intake valve and an exhaust valve. In a two-stroke internal combustion engine equipped with a valve, the top surface of the piston is separated from the bottom of the intake valve. It is characterized in that it is formed in a part of a concave cylindrical surface extending over the lower part of the exhaust valve.
【０００５】[0005]
燃焼室内の新気及び排気の流れは、ピストン上面の形状に案内されて縦回りの Ｕ字状に流れ、タンブル流（縦過流）が増加する。 The flow of fresh air and exhaust gas in the combustion chamber is guided by the shape of the top surface of the piston and flows vertically. It flows in a U-shape, and tumble flow (vertical overflow) increases.
【０００６】[0006]
図１には本考案の一実施例に係る２サイクル内燃機関の概略構成を示してある 。 FIG. 1 shows a schematic configuration of a two-stroke internal combustion engine according to an embodiment of the present invention. .
【０００７】 ２サイクル内燃機関の本体１０はシリンダブロック１１とシリンダヘッド１２ により構成され、ピストン１３の上方に燃焼室１４が形成される。シリンダヘッ ド１２には排気通路１５と新気供給系としての吸気通路１６が設けられている。 排気通路１５及び吸気通路１６にはポペット弁からなる排気弁１７及び吸気弁１ ８が設けられ、シリンダヘッド１２には排気ポート１９と吸気ポート２０とが形 成される。燃焼室１４の略中央には点火プラグ２１が設けられている。[0007] A main body 10 of a two-stroke internal combustion engine includes a cylinder block 11 and a cylinder head 12. A combustion chamber 14 is formed above the piston 13. cylinder head The door 12 is provided with an exhaust passage 15 and an intake passage 16 as a fresh air supply system. The exhaust passage 15 and the intake passage 16 are provided with an exhaust valve 17 and an intake valve 1 made of poppet valves. 8 is provided, and the cylinder head 12 is formed with an exhaust port 19 and an intake port 20. will be accomplished. An ignition plug 21 is provided approximately at the center of the combustion chamber 14 .
【０００８】 ピストン１３の上面３１は、吸気弁１８の下部から排気弁１７の下部に亘り凹 状の円筒面の一部の状態に形成されている。燃焼室１４内に新気が流入すると、 排気及び新気はピストン１３の上面３１の円筒面に案内されてタンブル流となっ て流れる（図中矢印で示す）。[0008] The upper surface 31 of the piston 13 is concave from the lower part of the intake valve 18 to the lower part of the exhaust valve 17. It is formed in the state of a part of a cylindrical surface. When fresh air flows into the combustion chamber 14, Exhaust air and fresh air are guided by the cylindrical surface of the upper surface 31 of the piston 13 and become a tumble flow. (indicated by the arrow in the figure).
【０００９】 上述した２サイクル内燃機関の作用を説明する。この２サイクル内燃機関は、 ピストン１３が上死点ＴＤＣから下死点ＢＤＣへ下降していく膨張行程と、下死 点ＢＤＣから上死点ＴＤＣへ上昇していく圧縮行程の２行程からなり、排気と吸 気はこの２行程の間に下死点ＢＤＣの近くで行なわれる。吸気通路１６から押し 込まれた新気が排気ガスを押し出しつつガス交換（掃気）を行なう。[0009] The operation of the above-mentioned two-stroke internal combustion engine will be explained. This two-stroke internal combustion engine is The expansion stroke in which the piston 13 descends from the top dead center TDC to the bottom dead center BDC, and the bottom dead center It consists of two strokes, the compression stroke rising from point BDC to top dead center TDC, and the exhaust and intake strokes. Ki is performed near the bottom dead center BDC during these two strokes. Push from the intake passage 16 Gas exchange (scavenging) is performed while the introduced fresh air pushes out exhaust gas.
【００１０】 膨張行程時に新気が押し込まれると、新気及び排気ガスの流れはピストン１３ の上面の円筒面に案内されて縦回りのＵ字状の流れとなり、タンブル流が増加す る。このため、掃気が充分に行なわれる。0010 When fresh air is forced in during the expansion stroke, the flow of fresh air and exhaust gas is directed to the piston 13. The flow is guided by the cylindrical surface on the top and forms a vertical U-shaped flow, increasing the tumble flow. Ru. Therefore, sufficient scavenging is performed.
【００１１】[0011]
【考案の効果】 本考案の２サイクル内燃機関は、ピストンの上面を、吸気弁の下部から排気弁 の下部に亘り凹状の円筒面の一部の状態に形成したので、新気が押し込まれた際 の新気及び排気がピストンの上面に案内されて縦回りのＵ字状の流れを形成し、 タンブル流が増加する。この結果、排気ガスが確実に排出され、掃気性向上が図 れる。[Effect of the idea] The two-stroke internal combustion engine of this invention moves the upper surface of the piston from the lower part of the intake valve to the exhaust valve. Since it is formed as part of a concave cylindrical surface across the lower part of the Fresh air and exhaust gas are guided to the top surface of the piston to form a vertical U-shaped flow, Tumble flow increases. As a result, exhaust gas is reliably discharged and scavenging performance is improved. It will be done.
【図１】本考案の一実施例に係る２サイクル内燃機関の
概略構成図。FIG. 1 is a schematic configuration diagram of a two-stroke internal combustion engine according to an embodiment of the present invention.
１０ 本体 １１ シリンダブロック １２ シリンダヘッド １３ ピストン １４ 燃焼室 １５ 排気通路 １６ 吸気通路 １７ 排気弁 １８ 吸気弁 ２１ 点火プラグ ３１ 上面 10 Main body 11 Cylinder block 12 Cylinder head 13 Piston 14 Combustion chamber 15 Exhaust passage 16 Intake passage 17 Exhaust valve 18 Intake valve 21 Spark plug 31 Top surface
Claims (1)
えた２サイクル内燃機関において、ピストンの上面を、
吸気弁の下部から排気弁の下部に亘り凹状の円筒面の一
部の状態に形成したことを特徴とする２サイクル内燃機
関。Claim 1: In a two-stroke internal combustion engine equipped with an intake valve and an exhaust valve in the cylinder head, the upper surface of the piston is
A two-stroke internal combustion engine characterized in that a part of a concave cylindrical surface is formed extending from the lower part of the intake valve to the lower part of the exhaust valve.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP3248291U JPH04127839U (en) | 1991-05-10 | 1991-05-10 | 2-stroke internal combustion engine |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP3248291U JPH04127839U (en) | 1991-05-10 | 1991-05-10 | 2-stroke internal combustion engine |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH04127839U true JPH04127839U (en) | 1992-11-20 |
Family
ID=31915412
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP3248291U Withdrawn JPH04127839U (en) | 1991-05-10 | 1991-05-10 | 2-stroke internal combustion engine |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH04127839U (en) |
-
1991
- 1991-05-10 JP JP3248291U patent/JPH04127839U/en not_active Withdrawn
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| A300 | Application deemed to be withdrawn because no request for examination was validly filed |
Free format text: JAPANESE INTERMEDIATE CODE: A300 Effective date: 19950810 |