JPH0223688B2 - - Google Patents
Info
- Publication number
- JPH0223688B2 JPH0223688B2 JP56023527A JP2352781A JPH0223688B2 JP H0223688 B2 JPH0223688 B2 JP H0223688B2 JP 56023527 A JP56023527 A JP 56023527A JP 2352781 A JP2352781 A JP 2352781A JP H0223688 B2 JPH0223688 B2 JP H0223688B2
- Authority
- JP
- Japan
- Prior art keywords
- intake passage
- reed valve
- valve
- timing
- intake
- 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.)
- Expired - Lifetime
Links
Classifications
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
- F01L—CYCLICALLY OPERATING VALVES FOR MACHINES OR ENGINES
- F01L7/00—Rotary or oscillatory slide valve-gear or valve arrangements
- F01L7/12—Rotary or oscillatory slide valve-gear or valve arrangements specially for two-stroke engines
-
- 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)
- Mechanical Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Supercharger (AREA)
Description
【発明の詳細な説明】
この発明は２サイクルエンジンの吸気装置に関
し、リード弁を設けた吸気通路の該リード弁より
気化器側において、該吸気通路より分岐し、途中
に回転弁を介してクランク室と連通する補助吸気
通路を設けることによつて、効率のよいエンジン
を得るようにしたものである。DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an intake system for a two-stroke engine, and relates to an intake passage provided with a reed valve, which branches from the intake passage on the side of the carburetor from the reed valve, and connects the intake passage to the crankshaft via a rotary valve in the middle. By providing an auxiliary intake passage communicating with the chamber, an efficient engine can be obtained.
クランク室予圧縮型２サイクルエンジンにおい
て、吸気の吹き返しを防ぐ手段として吸気通路に
リード弁を設けることがよく行われているが、リ
ード弁を利用した場合の特有の問題として、ある
回転域において、リード弁の固有振動による共振
や排気脈動による影響がマイナスに作用し、出力
特性に谷部（出力低下）が生ずる。この谷部はリ
ード弁の場合には吸気タイミングを遅らせること
によつて出力特性を全体的に低下させれば出力谷
が緩和されて円滑な出力特性の得られることが実
験の結果確認された。しかし、この場合にはエン
ジンの出力が全体的に下がる事態を招く結果とな
る。 In a two-stroke engine with precompression in the crank chamber, a reed valve is often installed in the intake passage as a means of preventing intake air from blowing back. However, a particular problem when using a reed valve is that Resonance due to the natural vibration of the reed valve and the effects of exhaust pulsation have a negative effect, causing a trough (lower output) in the output characteristics. Experiments have confirmed that in the case of a reed valve, if the intake timing is delayed to lower the output characteristics as a whole, the output valleys can be alleviated and smooth output characteristics can be obtained. However, in this case, the overall output of the engine is reduced.
本発明は、吸気通路の途中にリード弁を設けた
２サイクルエンジンにおいて、上記吸気通路の上
記リード弁より気化器側から分岐してクランク室
へ連通する補助吸気通路を設け、該補助吸気通路
に上記リード弁の機能を補助する回転弁を設け、
上記リード弁の開タイミングを最高出力発生タイ
ミングより遅く設定するとともに、上記回転弁の
開、閉タイミングのそれぞれを上記リード弁の
開、閉タイミングより早く設定したことを特徴と
している。 The present invention provides a two-stroke engine in which a reed valve is provided in the middle of an intake passage, and an auxiliary intake passage is provided that branches from the reed valve of the intake passage on the carburetor side and communicates with the crank chamber. A rotary valve is installed to assist the function of the reed valve mentioned above.
It is characterized in that the opening timing of the reed valve is set later than the maximum output generation timing, and the opening and closing timings of the rotary valve are respectively set earlier than the opening and closing timings of the reed valve.
ここで、本発明における最高出力発生タイミン
グとは、そのエンジンの特性に応じて異なるため
実験等で求める必要があるが、要は、出力が最大
になるタイミングであり、従来のエンジンはこの
タイミングに設定されている。そして一般にこの
最高出力発生タイミングに設定すると、例えば中
速域で出力の谷部が発生する。 Here, the maximum output generation timing in the present invention differs depending on the characteristics of the engine, so it needs to be determined through experiments, etc., but the important point is the timing at which the output is maximum, and conventional engines do not reach this timing. It is set. Generally, when the maximum output timing is set, a trough in the output occurs, for example, in the middle speed range.
また本発明において、最高出力発生タイミング
より遅く設定する場合の程度は、これもエンジン
特性によつて異なることから実験等によつて求め
る必要があるが、要は、上述の最高出力発生タイ
ミングの場合に生じる出力谷を実用上支障のない
範囲まで軽減できる程度に遅らせればよい。 In addition, in the present invention, the degree to which the maximum output generation timing is set later than the maximum output generation timing needs to be determined through experiments etc. as this also differs depending on the engine characteristics, but the point is that when the maximum output generation timing is set as described above, It is only necessary to delay the output trough that occurs in the output to a level that does not pose a practical problem.
本発明によれば、リード弁側の吸気タイミング
を従来のものより遅らせたので出力谷が緩和され
る。一方、このタイミング遅れによる出力特性の
全体的ダウンは回転弁側で補われる。その結果、
従来のリード弁方式と同等あるいはそれ以上の出
力も確保することが可能となる。 According to the present invention, the intake timing on the reed valve side is delayed compared to the conventional one, so that the output valley is alleviated. On the other hand, the overall decrease in output characteristics due to this timing delay is compensated for on the rotary valve side. the result,
It is also possible to secure an output equal to or greater than that of the conventional reed valve system.
この発明の実施例を図面について説明すると、
２サイクルエンジンＥのシリンダ５の吸気通路１
０にリード弁１を設け、該リード弁１の外側には
下側に分岐吸気通路３1を設けた吸気管２の一端
を取付け、該吸気管２の他端には気化器９を連結
する。一方、前記分岐吸気通路３1はシリンダ部
分の通路３2、クランクケース部の通路３3とで補
助吸気通路としての下側吸気通路３を構成してク
ランク室と連通しその途中にはスリーブ４が設け
られる。該スリーブ弁４はクランク軸に同期して
第１図矢印方向に回転するもので、その周壁上に
は180゜離れて２個の開口４1，４2が形成されてお
り、ピストンが下死点から上死点に移動する上昇
工程時のみ前記下側吸気通路３の上、下流を連通
させクランク軸が360゜回転して再び第１図のよう
な位置に来たとき、スリーブ弁４は180゜回転して
開口４1と４2が入れかわり、再びピストンの下死
点から上死点に亘つて前記下側吸気通路３に連通
するようにクランク軸の1/2の速さで回転する。
なお、６はピストン、７はクランクケースであ
り、８はシリンダヘツドである。 An embodiment of this invention will be explained with reference to the drawings.
Intake passage 1 of cylinder 5 of 2-cycle engine E
A reed valve 1 is provided at the reed valve 1, one end of an intake pipe 2 having a branch intake passage 31 on the lower side is attached to the outside of the reed valve 1, and a carburetor 9 is connected to the other end of the intake pipe 2. . On the other hand, the branch intake passage 3 1 constitutes a lower intake passage 3 as an auxiliary intake passage with a passage 3 2 in the cylinder portion and a passage 3 3 in the crankcase portion, and communicates with the crank chamber. is provided. The sleeve valve 4 rotates in the direction of the arrow shown in FIG. The sleeve valve 4 communicates between the upper and downstream parts of the lower intake passage 3 only during the ascending process of moving from the point to the top dead center, and when the crankshaft rotates 360 degrees and returns to the position shown in Fig. The openings 4 1 and 4 2 are swapped by rotating 180 degrees, and the piston rotates at 1/2 the speed of the crankshaft so that it communicates with the lower intake passage 3 from the bottom dead center to the top dead center of the piston. do.
Note that 6 is a piston, 7 is a crankcase, and 8 is a cylinder head.
第２図はピストンの各位置に対するスリーブ弁
４の回転位置を示したものであり、ピストンが下
死点（BDC）を過ぎると直ちにスリーブ弁４の
開口４1，４2は下側吸気通路３に開口し上、下流
を連通させ、上死点（TDC）に達すると閉じて
次の下死点まで閉の状態が続く。この間スリーブ
弁４は180゜回転する。再び下死点から上死点にか
けては今度はスリーブ弁４の開口４1，４2が入れ
かわつた形となつて下側吸気通路３に開口するこ
とになる。以上の作動を吸気通路１０の吸気タイ
ミングとの関係で表わしたものが第３図で、吸気
通路１０はピストンによつて下死点後90゜より上
死点後90゜迄に亘つて開くように構成される。吸
気通路開の前後に点線で示した部分は従来のリー
ド弁方式の場合の吸気通路開の作動範囲を示した
ものである。従つて、本発明の場合には、その分
だけ従来より吸気タイミングを遅らせていること
になる。第４図は従来のリード弁方式、従来の
リード弁方式において吸気タイミングを遅らせた
場合、この発明のもののそれぞれのエンジン
回転数に対する出力特性の実験結果を表わしたも
のである。図中Ｐは従来のリード弁方式におけ
る出力谷を表わしている。 FIG. 2 shows the rotational position of the sleeve valve 4 with respect to each position of the piston, and as soon as the piston passes the bottom dead center (BDC), the openings 4 1 and 4 2 of the sleeve valve 4 open the lower intake passage 3. It opens to connect the top and downstream, and when it reaches top dead center (TDC), it closes and remains closed until the next bottom dead center. During this time, the sleeve valve 4 rotates 180 degrees. From the bottom dead center to the top dead center again, the openings 4 1 and 4 2 of the sleeve valve 4 are switched and open to the lower intake passage 3. Figure 3 shows the above operation in relation to the intake timing of the intake passage 10.The intake passage 10 is opened by the piston from 90 degrees after bottom dead center to 90 degrees after top dead center. It is composed of The portions shown by dotted lines before and after opening the intake passage indicate the operating range of opening the intake passage in the case of the conventional reed valve system. Therefore, in the case of the present invention, the intake timing is delayed by that much compared to the conventional method. FIG. 4 shows the experimental results of the conventional reed valve system, the conventional reed valve system with delayed intake timing, and the output characteristics of the present invention with respect to engine speed. P in the figure represents the output valley in the conventional reed valve system.
以上の構成により、エンジンを作動させピスト
ン６が下死点を通過すると、クランク室内が負圧
になると共に、スリーブ弁４が下側吸気通路３の
上下流を連通させるので、新気が該下側吸気通路
３からクランク室内に吸入され、続いて排気孔が
ピストンによつて閉ざされる下死点後90゜の位置
（第１図に二点鎖線で示した位置でピストンスカ
ート部の開口がリード弁側の吸気通路に達する）
でリード弁よりの新気もクランク室内に吸入され
ることになる。 With the above configuration, when the engine is operated and the piston 6 passes the bottom dead center, the inside of the crank chamber becomes negative pressure, and the sleeve valve 4 connects the upper and lower sides of the lower intake passage 3, so fresh air flows between the lower and lower intake passages. Air is drawn into the crank chamber from the side intake passage 3, and then the exhaust hole is closed by the piston at a position 90 degrees after bottom dead center (the opening of the piston skirt is at the position shown by the two-dot chain line in Figure 1). (reaches the intake passage on the valve side)
Fresh air from the reed valve is also sucked into the crank chamber.
この発明は以上説明したような構成を有するこ
とによつて、リード弁からの吸気タイミングが従
来のものより遅らされているので、従来問題とな
つていた出力谷が緩和される。一方、吸気タイミ
ングの遅れによるリード弁からの吸気量の減少分
は補助吸気通路からの吸気が補うので、出力も従
来のリード弁方式と同等あるいはそれ以上確保で
き、エンジンの全回転数に亘つて優れた出力特性
を有することが可能となる。 By having the configuration as described above, the present invention allows the intake timing from the reed valve to be delayed compared to the conventional one, thereby alleviating the output trough that has been a problem in the prior art. On the other hand, the decrease in the amount of intake air from the reed valve due to the delay in intake timing is compensated for by the intake from the auxiliary intake passage, so the output can be maintained at the same level or higher than the conventional reed valve system, and the output is maintained over the entire engine speed. It becomes possible to have excellent output characteristics.
第１図ないし第４図は本発明の一実施例の２サ
イクルエンジンを説明するための図であり、第１
図は断面図、第２図はスリーブ弁の作動位置を示
した説明図、第３図はリード弁およびスリーブ弁
の作動範囲を示した説明図であり、第４図は各弁
方式におけるエンジン回転数に対する出力特性の
実験結果を表わしたものである。
１……リード弁、２……吸気管、３……下側吸
気通路（補助吸気通路）、４……スリーブ弁、５
……シリンダ、６……ピストン、７……クランク
室、１０……吸気通路。
Figures 1 to 4 are diagrams for explaining a two-stroke engine according to an embodiment of the present invention.
The figure is a sectional view, Figure 2 is an explanatory diagram showing the operating position of the sleeve valve, Figure 3 is an explanatory diagram showing the operating range of the reed valve and sleeve valve, and Figure 4 is an explanatory diagram showing the operating range of the reed valve and sleeve valve. This figure shows the experimental results of output characteristics with respect to numbers. 1...Reed valve, 2...Intake pipe, 3...Lower intake passage (auxiliary intake passage), 4...Sleeve valve, 5
...Cylinder, 6...Piston, 7...Crank chamber, 10...Intake passage.
Claims (1)
ルエンジンにおいて、上記吸気通路の上記リード
弁より気化器側から分岐してクランク室へ連通す
る補助吸気通路を設け、該補助吸気通路に上記リ
ード弁の機能を補助する回転弁を設け、上記リー
ド弁の開タイミングを最高出力発生タイミングよ
り遅く設定するとともに、上記回転弁の開、閉タ
イミングのそれぞれを上記リード弁の開、閉タイ
ミングより早く設定したことを特徴とする２サイ
クルエンジン。1. In a two-stroke engine in which a reed valve is provided in the middle of the intake passage, an auxiliary intake passage is provided that branches from the carburetor side of the intake passage and communicates with the crank chamber, and the auxiliary intake passage is provided with the reed valve in the auxiliary intake passage. A rotary valve is provided to assist the function, and the opening timing of the reed valve is set later than the maximum output generation timing, and the opening and closing timings of the rotary valve are respectively set earlier than the opening and closing timings of the reed valve. A 2-stroke engine with the following characteristics.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2352781A JPS57137611A (en) | 1981-02-19 | 1981-02-19 | Two-cycle engine |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2352781A JPS57137611A (en) | 1981-02-19 | 1981-02-19 | Two-cycle engine |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS57137611A JPS57137611A (en) | 1982-08-25 |
| JPH0223688B2 true JPH0223688B2 (en) | 1990-05-25 |
Family
ID=12112912
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP2352781A Granted JPS57137611A (en) | 1981-02-19 | 1981-02-19 | Two-cycle engine |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS57137611A (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| SE8305846A0 (en) * | 1983-10-25 | 1985-04-26 | Liebst Staffan | Intake system for two stroke engine |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS56163624U (en) * | 1980-05-06 | 1981-12-04 |
-
1981
- 1981-02-19 JP JP2352781A patent/JPS57137611A/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| JPS57137611A (en) | 1982-08-25 |
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