JPH03182620A - Two-cycle engine - Google Patents
Two-cycle engineInfo
- Publication number
- JPH03182620A JPH03182620A JP32006389A JP32006389A JPH03182620A JP H03182620 A JPH03182620 A JP H03182620A JP 32006389 A JP32006389 A JP 32006389A JP 32006389 A JP32006389 A JP 32006389A JP H03182620 A JPH03182620 A JP H03182620A
- Authority
- JP
- Japan
- Prior art keywords
- crank chamber
- piston
- volume
- scavenging port
- 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.)
- Pending
Links
- 230000002000 scavenging effect Effects 0.000 claims abstract description 24
- 238000005086 pumping Methods 0.000 abstract description 7
- 230000006835 compression Effects 0.000 abstract description 5
- 238000007906 compression Methods 0.000 abstract description 5
- 238000002485 combustion reaction Methods 0.000 abstract description 3
- 230000007423 decrease Effects 0.000 abstract description 3
- 239000000446 fuel Substances 0.000 description 7
- 235000014676 Phragmites communis Nutrition 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- NINIDFKCEFEMDL-UHFFFAOYSA-N Sulfur Chemical compound [S] NINIDFKCEFEMDL-UHFFFAOYSA-N 0.000 description 1
- 238000007664 blowing Methods 0.000 description 1
- 230000003247 decreasing effect Effects 0.000 description 1
- 230000006866 deterioration Effects 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 238000002347 injection Methods 0.000 description 1
- 239000007924 injection Substances 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- 229910052717 sulfur Inorganic materials 0.000 description 1
- 239000011593 sulfur Substances 0.000 description 1
- 238000010408 sweeping Methods 0.000 description 1
Classifications
-
- 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
- Supercharger (AREA)
Abstract
Description
【発明の詳細な説明】
（産業上の利用分野）
本発明は、シリンダ掃気のためにクランク室で圧縮され
た新式を利用する２ストロークエンノンに関する。DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a two-stroke ennon that utilizes a new type of compressed air in the crankcase for cylinder scavenging.
（従来の技術およびその課題〉
ピストンの下降に伴ってクランク室で圧縮される空気を
シリンダの掃気に用いる２ストロークエンジンは基本的
に掃ス流を圧送する過給機等が不要となる（例えば実開
昭６０−３９７３１号公報参照）。(Prior art and its problems) A two-stroke engine that uses air compressed in the crank chamber as the piston descends to scavenge the cylinder basically eliminates the need for a supercharger or the like to forcefully feed the scavenging flow (for example, (Refer to Utility Model Application Publication No. 60-39731).
従来、このようにクランク室で圧縮空気をつくるタイプ
の２ストロークエンジンでは、クランク室の容積をでき
るだけ小さくして、掃気ポートからシリンダ内に流入す
る空気の流速を高めようとする傾向があった。Conventionally, in two-stroke engines that generate compressed air in the crank chamber, there has been a tendency to reduce the volume of the crank chamber as much as possible to increase the flow velocity of air flowing into the cylinder from the scavenging port.
しかしながら、クランク室の容積をあまり小さくすると
、クランク室の圧縮に伴うピストンのボンピングロスが
増大し、燃費や出力の悪化を招くという問題点が生じた
。However, if the volume of the crank chamber is made too small, piston pumping loss due to compression of the crank chamber increases, resulting in a problem of deterioration of fuel efficiency and output.
本発明は、こうした従来の問題点に着目して、クランク
室の容積を適正にするものである。The present invention focuses on these conventional problems and optimizes the volume of the crank chamber.
（問題点を解決するための手段）
本発明では、シリンダの途中に掃気ポートが閉口し、こ
の掃気ポートをクランク室に連通し、ピストンの往復動
によってクランク室で圧縮された空気を掃気ポートを通
してシリンダ内に流入させる２ストロークエンジンにお
いて、行程容積に討してピストンが下死点にあるときの
クランク室側の容積の比率を略３．５に設定した。(Means for Solving Problems) In the present invention, a scavenging port is closed in the middle of the cylinder, this scavenging port is communicated with the crank chamber, and air compressed in the crank chamber by the reciprocating motion of the piston is passed through the scavenging port. In a two-stroke engine that allows air to flow into the cylinder, the ratio of the volume on the crank chamber side when the piston is at the bottom dead center relative to the stroke volume is set to approximately 3.5.
（作用）
上記構成に基づき、ピストンによるクランク室の圧縮を
過剰に高めることがなく、ピストンによるクランク室の
圧縮に伴うボンピングロスを増大させることを抑制する
とともに、掃気ポートの開通初期にクランク室から圧送
される新気が燃焼行程を迎えることなく排気ポートに吹
き抜けることを抑制し、新式の充填効率を高められる。(Function) Based on the above configuration, the compression of the crank chamber by the piston is not increased excessively, and the increase in the pumping loss due to the compression of the crank chamber by the piston is suppressed. This suppresses the pressure-fed fresh air from blowing into the exhaust port without undergoing the combustion process, increasing the new type's charging efficiency.
また、ピストンによるクランク室の圧縮が不足すること
がなく、必要な掃気量を確保して残留〃スを十分に低減
できる。Further, the compression of the crank chamber by the piston will not be insufficient, and the necessary amount of scavenging air can be secured and residual gas can be sufficiently reduced.
（実施例）
以下、本発明の実施例を添付図面ｌこ基づいて説明する
。(Embodiments) Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.
第１図に示すように、２ストロークエンジン１はシリン
ダ２の壁面にクランク室３と連通する掃気ポート４が閉
口するとともに、排気ポート５が閉口する。この排気ポ
ート５と掃気ポート４はそれぞれピストン８の往復動に
より開閉され、下死点（ＢＤＣ）を挾んで対称な所定の
クランク角度でそれぞれ開き、既燃焼がスを排気ポート
５から排出しつつ、クランク室３から掃気ポート４を通
して新気を送り込むようになっている。As shown in FIG. 1, in a two-stroke engine 1, a scavenging port 4 communicating with a crank chamber 3 on a wall surface of a cylinder 2 is closed, and an exhaust port 5 is closed. The exhaust port 5 and the scavenging port 4 are opened and closed by the reciprocating movement of the piston 8, respectively, and open at a predetermined crank angle symmetrical to the bottom dead center (BDC), thereby exhausting the burned gas from the exhaust port 5. , fresh air is sent from the crank chamber 3 through the scavenging port 4.
クランク室３には吸六口６が閉口し、図示しないエアク
リーナ、スａットルバルプおよび気化器等を経て作られ
る混合気がリードバルブ７を介して流入する上うになっ
ている。A six-port intake 6 is closed in the crank chamber 3, and an air-fuel mixture created through an air cleaner, a throttle valve, a carburetor, etc. (not shown) flows into the crank chamber 3 via a reed valve 7.
なお、図中９は燃料噴射弁、１０は点火プラグ、１１は
クランク軸である。In addition, in the figure, 9 is a fuel injection valve, 10 is a spark plug, and 11 is a crankshaft.
本発明は、ピストン下死点時におけるクランク室３のピ
ストン８の背面とリードバルブ７およびクランクケース
１３等に画成されるクランク室容積を■３、掃気ポート
４の容積を■いシリンダ２とピストン８のボア、ストロ
ークより画成される行程容積（シリンダ側容積）をＶ２
とすると、クランク室３側の容積比Ｃ＝ （Ｖ ｓ 十
Ｖ ４ ） ／ Ｖ ２の値を限定するものである。In the present invention, the volume of the crank chamber defined by the back surface of the piston 8 of the crank chamber 3, the reed valve 7, the crank case 13, etc. at the time of piston bottom dead center is 3, and the volume of the scavenging port 4 is 2. The stroke volume (cylinder side volume) defined by the bore and stroke of the piston 8 is V2.
Then, the value of the volume ratio C=(V s +V 4 )/V 2 on the crank chamber 3 side is limited.
ｖ＆２図は上記クランク室３＠の容積比Ｃを変数として
エンジン１の発生トルクに当たる平均有効圧を測定した
実験結果を示すが、平均有効圧は容積比Ｃが３以下の領
域で大きく低下し、また容積比Ｃｈｔ ４以上の領域で
も徐々に低下しており、容積比Ｃが３．５付近で最も高
い値が得られた。Figure v & 2 shows the experimental results of measuring the average effective pressure corresponding to the torque generated by the engine 1 using the volume ratio C of the crank chamber 3 as a variable, but the average effective pressure decreases significantly in the region where the volume ratio C is 3 or less, Moreover, it gradually decreased even in the region where the volume ratio Cht was 4 or more, and the highest value was obtained when the volume ratio C was around 3.5.
第３図はクランク室３＠の容積比Ｃを変数としてエンノ
ン１の所定運転条件で燃料消費率を測定した実験結果を
示すが、燃料消費率は容積比Ｃが３以下の領域で大きく
増大し、また容積比Ｃが４以上の領域でも徐々に増大し
ており、容積比Ｃが３．５付近で最も低い値が得られた
。Figure 3 shows the experimental results of measuring the fuel consumption rate under specified operating conditions of Ennon 1 using the volume ratio C of the crank chamber 3@ as a variable.The fuel consumption rate greatly increases in the region where the volume ratio C is 3 or less. , and also gradually increased in the region where the volume ratio C was 4 or more, and the lowest value was obtained when the volume ratio C was around 3.5.
なお、第２図、第３図において、破線で示す図示値と実
線で示す正味値の差はクランク室３側の容積比Ｃが３以
下の領域でそれぞれ大幅に増大し、４：の領域でボンピ
ングロス等の損失が増大していることがわかる。In addition, in Figs. 2 and 3, the difference between the indicated value shown by the broken line and the net value shown by the solid line increases significantly in the region where the volume ratio C on the crank chamber 3 side is 3 or less, and in the region of 4:. It can be seen that losses such as bombing loss are increasing.
第４図はクランク室３側の容積比Ｃを変数としてエンジ
ン１の所定運転条件でシリンダに吸入される空只量を無
次元化した給気比を測定した実験結果を示すが、給気比
は燃料消費率を小さくする程増大するが、容積比Ｃが３
．５付近で十分に高い値が得られた。Fig. 4 shows the experimental results of measuring the air supply ratio, which is the dimensionless amount of air taken into the cylinder under predetermined operating conditions of the engine 1, using the volume ratio C on the side of the crank chamber 3 as a variable. increases as the fuel consumption rate decreases, but when the volume ratio C is 3
．． A sufficiently high value was obtained around 5.
本発明は、これらの実験結果に基づいてクランク室３の
容積比Ｃ＝ （Ｖ ：ｌ＋ Ｖ ４）／Ｖ ２を略３．
５に設定する。Based on these experimental results, the present invention sets the volume ratio C=(V:l+V4)/V2 of the crank chamber 3 to approximately 3.
Set to 5.
第５図はクランク室３１１Ｉｌの容積比Ｃを０．８０．
３．０２．６．００と変えて、エンジン１の所定運転条
件でクランク室３の圧力変化を測定した実験結果を示す
が、容積比Ｃを小さくする程、圧力変化の巾が大きくな
り、ボンピングロスが増大することがわかる。FIG. 5 shows the volume ratio C of the crank chamber 311Il as 0.80.
3.02.6.00, and measured the pressure change in the crank chamber 3 under the specified operating conditions of the engine 1. As the volume ratio C becomes smaller, the width of the pressure change becomes larger. It can be seen that the grossness increases.
クランク室３側の容積が過剰に大きい場合、例えば容積
比Ｃが６．００の場合は、第６図に示すように、クラン
ク室３のボンピング作用が小さくなり、十分な掃Ｘｔが
得られず、残留がスが生じる原因になった。If the volume on the crank chamber 3 side is excessively large, for example, if the volume ratio C is 6.00, the pumping action of the crank chamber 3 becomes small, as shown in Fig. 6, and sufficient sweeping Xt cannot be obtained. , the residue caused the occurrence of sulfur.
クランク室３ｇａの有効容積が過剰に小さい場合、例え
ば容積比Ｃが０．８０の場合は、第７図に示すように、
クランク室３のボンピング作用が大きくなり、掃気ポー
ト４の開通直後のクランク室３の圧力が高くなるため、
掃気ポート４の開通初期にクランク室３から圧送される
新式が燃焼行程を迎えることなく徘ヌポート５に吹き抜
けるため、充填効率の向上に結び付かない。If the effective volume of the crank chamber 3ga is excessively small, for example, if the volume ratio C is 0.80, as shown in FIG.
The pumping effect of the crank chamber 3 increases, and the pressure in the crank chamber 3 increases immediately after the scavenging port 4 opens.
Since the new type that is pressure-fed from the crank chamber 3 at the beginning of the opening of the scavenging port 4 blows through to the wandering port 5 without undergoing a combustion stroke, it does not lead to improvement in charging efficiency.
これに対して、第８図に示すように、本発明に基づいて
容積比Ｃを３．０２とした場合は、掃気ポート４の開通
直後のクランク室３の圧力の上昇が抑えられるため、掃
気ポート４がら徘スポート５に吹き抜ける新式の流出を
防止して、充填効率の向上がはかれる。さらに、掃気ポ
ート４の開通直後からピストン下死点付近に渡って新式
の流量を十分に確保して、掃気を促すことがでさる。On the other hand, as shown in FIG. 8, when the volume ratio C is set to 3.02 based on the present invention, the rise in pressure in the crank chamber 3 immediately after the scavenging port 4 is opened is suppressed, so that the scavenging The new type of outflow from the port 4 to the wandering port 5 is prevented, and the filling efficiency is improved. Furthermore, the new type of flow rate can be sufficiently ensured from immediately after the opening of the scavenging port 4 to near the bottom dead center of the piston to promote scavenging.
（発明の効果）
以−にの通り本発明によれば、ピストンの往ｍ動によっ
てクランク室で圧縮された空気を掃気ポートを通してシ
リンダ内に流入させる２ストロークエンジンにおいて、
行程容積に対してピストンが下死点にあるときにクラン
ク室側の容積の比率を略３．５に設定したため、ボンピ
ングロスの低減と充填効率の増大を両立し、２ストロー
クエンジンの燃費および発生トルクを改善することがで
きる。(Effects of the Invention) As described above, according to the present invention, in a two-stroke engine in which air compressed in the crank chamber by the forward movement of the piston flows into the cylinder through the scavenging port,
The ratio of the volume on the crank chamber side when the piston is at the bottom dead center to the stroke volume is set to approximately 3.5, which reduces pumping loss and increases charging efficiency, resulting in improved fuel efficiency and generation of 2-stroke engines. Torque can be improved.
第１図は本発明の実施例を示すエンノンの断面図、第２
図〜＠８図はそれぞれ実験結果を示す線図である。
１・・・２ストロークエンジン、２・・・シリンダ、３
・・・クランク室、４・・・掃気ポート、５・・・排ス
ポート、８・・・ピストン。Fig. 1 is a sectional view of an ennon showing an embodiment of the present invention;
Figures ~@8 are diagrams showing experimental results, respectively. 1... 2-stroke engine, 2... cylinder, 3
...Crank chamber, 4...Scavenging port, 5...Exhaust port, 8...Piston.
Claims (1)
をクランク室に連通し、ピストンの往復動によってクラ
ンク室で圧縮された空気を掃気ポートを通してシリンダ
内に流入させる２ストロークエンジンにおいて、行程容
積に対してピストンが下死点にあるときのクランク室側
の容積の比率を略３．５に設定したことを特徴とする２
ストロークエンジン。In a two-stroke engine, a scavenging port closes in the middle of the cylinder, communicating this scavenging port with the crank chamber, and allowing air compressed in the crank chamber by the reciprocating motion of the piston to flow into the cylinder through the scavenging port. The ratio of the volume on the crank chamber side when the piston is at the bottom dead center is set to approximately 3.5.
stroke engine.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP32006389A JPH03182620A (en) | 1989-12-08 | 1989-12-08 | Two-cycle engine |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP32006389A JPH03182620A (en) | 1989-12-08 | 1989-12-08 | Two-cycle engine |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH03182620A true JPH03182620A (en) | 1991-08-08 |
Family
ID=18117307
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP32006389A Pending JPH03182620A (en) | 1989-12-08 | 1989-12-08 | Two-cycle engine |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH03182620A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE4447215A1 (en) * | 1994-02-23 | 1995-08-24 | Daihatsu Motor Co Ltd | Two-stroke IC engine |
Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS54106723A (en) * | 1978-02-10 | 1979-08-22 | Nippon Soken Inc | 2-cycle engine |
-
1989
- 1989-12-08 JP JP32006389A patent/JPH03182620A/en active Pending
Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS54106723A (en) * | 1978-02-10 | 1979-08-22 | Nippon Soken Inc | 2-cycle engine |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE4447215A1 (en) * | 1994-02-23 | 1995-08-24 | Daihatsu Motor Co Ltd | Two-stroke IC engine |
| US5490483A (en) * | 1994-02-23 | 1996-02-13 | Daihatsu Motor Co., Ltd. | Two-cycle internal combustion engine |
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