JP2762122B2 - Exhaust control valve device for parallel multi-cylinder two-cycle engine - Google Patents
Exhaust control valve device for parallel multi-cylinder two-cycle engineInfo
- Publication number
- JP2762122B2 JP2762122B2 JP1207916A JP20791689A JP2762122B2 JP 2762122 B2 JP2762122 B2 JP 2762122B2 JP 1207916 A JP1207916 A JP 1207916A JP 20791689 A JP20791689 A JP 20791689A JP 2762122 B2 JP2762122 B2 JP 2762122B2
- Authority
- JP
- Japan
- Prior art keywords
- cylinder
- exhaust
- control valve
- exhaust control
- valve
- 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 - Fee Related
Links
Classifications
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02D—CONTROLLING COMBUSTION ENGINES
- F02D13/00—Controlling the engine output power by varying inlet or exhaust valve operating characteristics, e.g. timing
- F02D13/02—Controlling the engine output power by varying inlet or exhaust valve operating characteristics, e.g. timing during engine operation
- F02D13/028—Controlling the engine output power by varying inlet or exhaust valve operating characteristics, e.g. timing during engine operation for two-stroke engines
- F02D13/0284—Variable control of exhaust valves only
-
- 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
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
- Y02T10/00—Road transport of goods or passengers
- Y02T10/10—Internal combustion engine [ICE] based vehicles
- Y02T10/12—Improving ICE efficiencies
Landscapes
- Engineering & Computer Science (AREA)
- Chemical & Material Sciences (AREA)
- Combustion & Propulsion (AREA)
- Mechanical Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Output Control And Ontrol Of Special Type Engine (AREA)
- Combustion Methods Of Internal-Combustion Engines (AREA)
- Control Of Throttle Valves Provided In The Intake System Or In The Exhaust System (AREA)
Description
【発明の詳細な説明】 （産業上の利用分野） 本発明は、排気ポートの上縁付近に臨んで排気ポート
の開タイミングを可変とする排気制御弁を備えた並列多
気筒２サイクルエンジンの排気制御弁装置に関するもの
である。DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to an exhaust of a parallel multi-cylinder two-stroke engine provided with an exhaust control valve that faces the upper edge of an exhaust port and varies the opening timing of the exhaust port. The present invention relates to a control valve device.
（発明の背景） ２サイクルエンジンにおいては、排気ポートの開タイ
ミングを早くすることにより高回転域での高出力化が図
れるが、この時には低中速域での掃気が悪化して不整燃
焼が発生したり新気の吹き抜けにより燃費の悪化を招
く。そこで排気ポートの上縁付近に進退して排気ポート
の開タイミングを可変とする排気制御弁を設け、後続時
に開タイミングを早め、低中速時に遅らせるようにした
ものが実用化されている。(Background of the Invention) In a two-stroke engine, increasing the opening timing of the exhaust port can increase the output in a high rotation speed range, but at this time, scavenging in a low to middle speed range deteriorates and irregular combustion occurs. The fuel consumption is worsened by dripping or fresh air. Therefore, an exhaust control valve which moves forward and backward near the upper edge of the exhaust port and makes the opening timing of the exhaust port variable is provided, and the opening timing is advanced at the subsequent time and delayed at low to medium speeds.
一方２サイクルエンジンではシリンダに排気通路や掃
気通路が設けられるため、並列多気筒化する場合にシリ
ンダ間隔が拡大し、エンジンが大型化するという不都合
がある。そこで、各気筒のシリンダ中心を通る平面（シ
リンダ中心面）に直交しかつ各気筒のシリンダ中心軸を
通る各平面に対して、各気筒の排気通路を同一方向に傾
けることが考えられる。この場合、各気筒の排気制御弁
を共通１本の弁軸に設けて排気制御弁の駆動機構を簡単
にすることが考えられる。しかしこうすると排気制御弁
の弁軸は、排気ポート中心とシリンダ中心とを通る平面
に直交しなくなる。このためピストンが実質的に排気ポ
ートを最初に開き始める位置が、排気制御弁の開閉によ
ってシリンダに直交する平面上で変動する。すなわち排
気制御弁の開度によって、排気が始まる位置が変動する
ことになる。排気ポートの位置や点火栓の位置、あるい
は燃料噴射方式の場合における燃料の噴射位置は固定さ
れているから、排気が始まる位置が変動すると、掃気・
排気・燃焼条件などが変化することになり、好ましくな
い。On the other hand, in a two-cycle engine, since an exhaust passage and a scavenging passage are provided in a cylinder, there is a disadvantage that the cylinder interval is increased when the number of cylinders is increased and the engine is enlarged. Therefore, it is conceivable to incline the exhaust passage of each cylinder in the same direction with respect to each plane passing through the cylinder center axis of each cylinder and orthogonal to the plane passing through the cylinder center of each cylinder (cylinder center plane). In this case, it is conceivable to simplify the drive mechanism of the exhaust control valve by providing the exhaust control valve of each cylinder on one common valve shaft. However, in this case, the valve axis of the exhaust control valve is not perpendicular to a plane passing through the center of the exhaust port and the center of the cylinder. Therefore, the position at which the piston first starts to open the exhaust port substantially fluctuates on a plane orthogonal to the cylinder by opening and closing the exhaust control valve. That is, the position at which the exhaust starts is varied depending on the opening degree of the exhaust control valve. Since the position of the exhaust port, the position of the spark plug, and the position of the fuel injection in the case of the fuel injection system are fixed, if the position where the exhaust starts changes, the scavenging
Exhaust and combustion conditions change, which is not preferable.
（発明の目的） 本発明はこのような事情に鑑みなされたものであり、
各気筒の排気通路を、シリンダ中心面に直交しかつ各気
筒のシリンダ中心を通る平面に対して、同一方向に傾け
てエンジンの小型化を図る一方、各気筒の排気制御弁の
弁軸を共通な直線上に配置してこれらの駆動機構を簡素
化する場合において、排気制御弁の開度変化による排気
が始まる位置の変動が少なくなり、掃気・排気・燃焼条
件等の変動が少なく常に安定した運転を可能にする並列
多気筒２サイクルエンジンの排気制御弁装置を提供する
ことを目的とする。(Object of the Invention) The present invention has been made in view of such circumstances,
The exhaust passage of each cylinder is inclined in the same direction with respect to a plane perpendicular to the cylinder center plane and passing through the cylinder center of each cylinder to reduce the size of the engine, while sharing the valve shaft of the exhaust control valve of each cylinder. When these drive mechanisms are simplified by arranging them on a straight line, fluctuations in the position at which exhaust starts due to changes in the opening degree of the exhaust control valve are reduced, and fluctuations in scavenging, exhaust, combustion conditions, etc. are reduced and stable. An object of the present invention is to provide an exhaust control valve device for a parallel multi-cylinder two-cycle engine that enables operation.
（発明の構成） 本発明によればこの目的は、各気筒のシリンダ中心軸
を含むシリンダ中心面の一側に各気筒の排気通路が互い
に平行に設けられ、各排気通路の排気ポート上縁付近に
臨んで排気ポートの開くタイミングを可変とする排気制
御弁を備えた並列多気筒２サイクルエンジンにおいて、
各気筒のシリンダ中心を通りかつ前記シリンダ中心面に
直交する各平面に対して、前記各排気通路を同一方向に
傾け、前記各排気制御弁の弁軸部を前記シリンダ中心面
に平行な直線上で互いに連結する一方、前記排気ポート
の上縁を上方へ凸としてその中心付近を最も高く形成す
ると共に、この排気ポートの上縁外側に前記排気制御弁
の全開時に排気制御弁の下縁が排気ポートの上縁よりも
高くなるように進入する弁室を形成し、前記排気制御弁
の排気ポートに望む下縁を上方へ凸な略弧状として排気
制御弁の全閉時または半開時に排気制御弁の下縁中央付
近が最も高くなるようにしたことを特徴とする並列多気
筒２サイクルエンジンの排気制御弁装置、により達成さ
れる。(Constitution of the Invention) According to the present invention, an object of the present invention is to provide, in one side of a cylinder center plane including a cylinder center axis of each cylinder, exhaust passages of each cylinder provided in parallel with each other, and near an upper edge of an exhaust port of each exhaust passage. In a parallel multi-cylinder two-stroke engine equipped with an exhaust control valve that makes the opening timing of the exhaust port variable
Each exhaust passage is inclined in the same direction with respect to each plane passing through the cylinder center of each cylinder and orthogonal to the cylinder center plane, and the valve shafts of the respective exhaust control valves are aligned on a straight line parallel to the cylinder center plane. While the upper edge of the exhaust port is convex upward and the vicinity of the center thereof is formed highest, and the lower edge of the exhaust control valve is exhausted to the outside of the upper edge of the exhaust port when the exhaust control valve is fully opened. A valve chamber which enters so as to be higher than an upper edge of the port is formed, and a lower edge desired for an exhaust port of the exhaust control valve is formed to have a substantially arc shape convex upward, and the exhaust control valve is fully closed or half-open when the exhaust control valve is fully opened. And the center of the lower edge is set to be the highest.
（実施例） 第１図は本発明の一実施例である３気筒エンジンの平
断面図、第２図はそのII−II線で断面したエンジン全体
の断面図である。なお第１図は第２図におけるＩ−Ｉ線
で断面したものである。また第3A、3B、3C図は燃焼室側
から見た排気ポートの形状を示す図であって、第3A図は
本発明の実施例ではない高速重視のものを、第3B図と第
3C図はそれぞれ本発明の実施例である中速および高速重
視のものと、低速および高速重視のものを示す。(Embodiment) FIG. 1 is a plan sectional view of a three-cylinder engine according to an embodiment of the present invention, and FIG. 2 is a sectional view of the entire engine taken along the line II-II. FIG. 1 is a cross-sectional view taken along the line II in FIG. 3A, 3B, and 3C are diagrams showing the shape of the exhaust port as viewed from the combustion chamber side, and FIG. 3A is a diagram of a high-speed emphasis which is not an embodiment of the present invention, and FIG. 3B and FIG.
FIG. 3C shows an example of the present invention emphasizing medium speed and high speed and an example emphasizing low speed and high speed, respectively.
第２図において符号10はシリンダボデー、12はクラン
クケース、14はシリンダヘッドであり、３つの気筒のシ
リンダ中心線Ａ、Ｂ、Ｃ（第１図）は１つの平面すなわ
ちシリンダ中心面Ｄ上に位置している。第２図で16はク
ランク軸、18はピストン、20はコンロッドである。クラ
ンクケース12のクランク室22へはリード弁24を介して空
気が吸入され、ピストン18の下降により圧縮されたクラ
ンク室22内の空気は各気筒の３つの掃気通路26（26a、
ｂ、ｃ）に導かれて掃気ポート28（28a、ｂ、ｃ）から
燃焼室30に流入する。32は排気通路であり、中央の掃気
ポート28aに対向する排気ポート34に連通する。ここに
各気筒の掃気ポート28および排気ポート34は、第１図に
示すように、隣接する気筒の排気通路32および掃気通路
26が干渉しないようにシリンダ中心軸Ａ、Ｂ、Ｃ上で同
一方向にそれぞれ同一角度回転された位置にある。すな
わち掃・排気通路26、32は、各気筒のシリンダ中心軸
Ａ、Ｂ、Ｃを通りかつシリンダ中心面Ｄに直交する３つ
の平面Ｅ、Ｆ、Ｇに対して、同一方向すなわち第１図で
時計方向に同一角度傾いている。In FIG. 2, reference numeral 10 denotes a cylinder body, 12 denotes a crankcase, 14 denotes a cylinder head, and the cylinder center lines A, B, and C of the three cylinders (FIG. 1) are on one plane, that is, the cylinder center plane D. positioned. In FIG. 2, 16 is a crankshaft, 18 is a piston, and 20 is a connecting rod. Air is sucked into the crank chamber 22 of the crank case 12 via a reed valve 24, and the air in the crank chamber 22 compressed by the lowering of the piston 18 is supplied to the three scavenging passages 26 (26a,
b, c) and flows into the combustion chamber 30 from the scavenging port 28 (28a, b, c). An exhaust passage 32 communicates with an exhaust port 34 facing the scavenging port 28a at the center. Here, the scavenging port 28 and the exhaust port 34 of each cylinder are connected to the exhaust passage 32 and the scavenging passage of the adjacent cylinder as shown in FIG.
26 are positioned at the same angle on the cylinder center axes A, B and C in the same direction so as not to interfere. That is, the sweep / exhaust passages 26 and 32 are in the same direction, that is, in FIG. 1 with respect to three planes E, F and G passing through the cylinder center axes A, B and C of each cylinder and orthogonal to the cylinder center plane D. It is inclined at the same angle clockwise.
36は排気制御弁である。この排気制御弁36の弁軸部38
は各気筒の排気通路32の上壁側に位置し、弁36の回動端
は排気ポート34の上縁付近で上下に移動する。すなわち
排気ポート34の上縁外側には第２、3A〜Ｃ図に示す弁室
40が形成され、弁軸部38を第２図で反時計方向に回動す
れば弁36の回動端はこの弁室40内に入って行き、第3A〜
Ｃ図に二点鎖線で示すように弁36の下縁は排気ポート34
の上縁の上方に位置する。この時排気ポート34の開タイ
ミングは最も早くなる。また弁軸部38を時計方向に回動
すれば弁36の回動端は弁室40から下方に退出して行き、
弁36の下縁は排気ポート34上縁より大きく下降し、第3A
〜Ｃ図に一点鎖線で示す位置に来る。このため実質的に
排気ポート34の開タイミングが最も遅れる。36 is an exhaust control valve. The valve shaft 38 of the exhaust control valve 36
Is located on the upper wall side of the exhaust passage 32 of each cylinder, and the rotating end of the valve 36 moves up and down near the upper edge of the exhaust port 34. That is, the valve chamber shown in FIGS.
When the valve shaft 38 is rotated counterclockwise in FIG. 2, the rotating end of the valve 36 enters the valve chamber 40, and the third shaft 40 is formed.
As shown by the two-dot chain line in FIG.
Is located above the upper edge of the At this time, the opening timing of the exhaust port 34 is the earliest. If the valve shaft 38 is rotated clockwise, the rotating end of the valve 36 retreats downward from the valve chamber 40,
The lower edge of the valve 36 descends more than the upper edge of the exhaust port 34,
ＣC to the position indicated by the alternate long and short dash line. Therefore, the opening timing of the exhaust port 34 is delayed most substantially.
ここに弁36の弁軸部38はシリンダ中心面Ｄと平行であ
り、弁36の回動端の下縁は上方に向って凸となるように
ほぼ弧状に形成されている。この下縁の形状は、高速用
エンジンの場合には、第3A図に示すように、弁36の開い
た高速時に排気ポート34の上縁にほぼ一致し、ピストン
が最初に開く位置αがポートの左右方向の中央に位置す
るように設定される。中速重視のエンジンでは、第3B図
に三点鎖線36aで示すように、弁36の半開時にピストン
が最初に開く位置βがポートの左右方向中央に位置する
ように設定される。さらに低速重視のエンジンでは、第
3C図に示すように、弁36の下降した低速時においてピス
トンが最初に開く位置γがポートの左右方向の中央に位
置するように設定される。この結果、弁36の回動により
ピストンがポートを最初に開く位置の変動範囲は、それ
ぞれla、lb、lcのように小さくなる。Here, the valve shaft portion 38 of the valve 36 is parallel to the cylinder center plane D, and the lower edge of the rotating end of the valve 36 is formed in a substantially arc shape so as to protrude upward. In the case of a high-speed engine, the shape of the lower edge substantially coincides with the upper edge of the exhaust port 34 when the valve 36 is open at a high speed, as shown in FIG. Is set to be located at the center in the left-right direction. In an engine that emphasizes medium speed, as shown by a three-dot chain line 36a in FIG. 3B, the position β at which the piston first opens when the valve 36 is half-opened is set at the center in the left-right direction of the port. In low-speed engines,
As shown in FIG. 3C, the position γ at which the piston first opens when the valve 36 is lowered at a low speed is set so as to be located at the center of the port in the left-right direction. As a result, the fluctuation range of the position where the piston first opens the port due to the rotation of the valve 36 is reduced to l a , l b , and l c , respectively.
以上の構成は各気筒に対して同一である。 The above configuration is the same for each cylinder.
各気筒の弁軸部38、38、38、は第１図に示すように、
シリンダ中心面Ｄと平行な直線上で連結されている。す
なわち第４図に示すように、弁軸部38にはその一端から
軸体38Aが貫挿され、この軸体38Aの先端が弁軸部38を貫
通して他端側の他の軸体38Bに嵌入されている。ここに
軸体38A、38Bと弁軸部38との対向面には、互いに係合し
て回転を伝えるための凸部38a、38bおよび凹部38c、38d
が形成されている。従って第１図に示すように各弁36の
弁軸部38は、順に軸体38A、38B、38C、38Dの間に挾持さ
れ、これらは一体に回動する。最上部の軸体38Aはシリ
ンダボデー10から上へ突出し、ここにプーリ42が固定さ
れている。このプーリ42はサーボモータ44に固定された
プーリ46にワイヤ48によって連動する。As shown in FIG. 1, the valve shaft portions 38, 38, 38 of each cylinder
They are connected on a straight line parallel to the cylinder center plane D. That is, as shown in FIG. 4, a shaft 38A is inserted through one end of the valve shaft 38, and the tip of the shaft 38A penetrates the valve shaft 38 and the other shaft 38B on the other end. It is inserted in. Here, on the opposing surfaces of the shaft bodies 38A, 38B and the valve shaft part 38, convex parts 38a, 38b and concave parts 38c, 38d for engaging with each other and transmitting rotation are provided.
Are formed. Therefore, as shown in FIG. 1, the valve shaft 38 of each valve 36 is sandwiched between the shafts 38A, 38B, 38C and 38D in order, and these rotate integrally. The uppermost shaft body 38A protrudes upward from the cylinder body 10, and a pulley 42 is fixed thereto. The pulley 42 is linked with a pulley 46 fixed to a servomotor 44 by a wire 48.
第２図において50は点火栓、52は電磁式燃料空気噴射
弁である。点火栓50の着火部50Aは、第１図に示すよう
に、排気ポート34の中心とシリンダ中心Ａとを結ぶ線よ
りも下方、すなわち排気通路32の傾き方向と反対方向に
偏位して点火と燃焼の向上が図られている。この噴射弁
52は燃料インジエクタ54から供給される燃料と、空気流
入口56から供給される高圧空気とを所定の混合比に混合
して燃焼室30内に噴射するものであり、噴射タイミング
は電磁ソレノイド58の励磁により制御される。In FIG. 2, reference numeral 50 denotes an ignition plug, and reference numeral 52 denotes an electromagnetic fuel air injection valve. As shown in FIG. 1, the ignition portion 50A of the ignition plug 50 is displaced below a line connecting the center of the exhaust port 34 and the cylinder center A, that is, in a direction opposite to the direction in which the exhaust passage 32 is inclined. And improvement of combustion is aimed at. This injection valve
Numeral 52 is for mixing the fuel supplied from the fuel injector 54 and the high-pressure air supplied from the air inlet 56 at a predetermined mixing ratio and injecting the mixture into the combustion chamber 30. Controlled by excitation.
次に動作を説明する。クランク軸16の回転により空気
がクランク室22内に吸入されピストン18の下降によりク
ランク室22内の空気が予圧される。ピストン18が掃気ポ
ート28を開くとクランク室22内の空気が燃焼室30内に流
入する。ピストン18の上昇により燃焼室30内が加圧さ
れ、その後所定のタイミングでソレノイド58が励磁さ
れ、燃料と空気の混合流が燃焼室30内に噴射される。そ
して所定タイミングに点火栓50により点火される。爆発
行程でピストン18が下降して行きピストン18が排気ポー
ト34を開くと、排気は排気通路32に導かれる。Next, the operation will be described. Air is sucked into the crank chamber 22 by the rotation of the crankshaft 16, and the air in the crank chamber 22 is pre-pressed by the lowering of the piston 18. When the piston 18 opens the scavenging port 28, the air in the crank chamber 22 flows into the combustion chamber 30. The inside of the combustion chamber 30 is pressurized by the rise of the piston 18, and then the solenoid 58 is excited at a predetermined timing, and a mixed flow of fuel and air is injected into the combustion chamber 30. Then, ignition is performed by the ignition plug 50 at a predetermined timing. When the piston 18 descends during the explosion stroke and the piston 18 opens the exhaust port 34, the exhaust is guided to the exhaust passage 32.
排気制御弁36はサーボモータ44によってその開度が制
御される。すなわち高速時には弁36は第3A〜Ｃ図の二点
鎖線の位置とされ、実質的に排気ポート34の開タイミン
グを早める。また低速時には弁36はそれぞれ一点鎖線の
位置とされて実質的に排気ポート34の開タイミングを遅
らせる。この結果全ての運転条件下で望ましい性能を得
ることができる。The opening of the exhaust control valve 36 is controlled by a servomotor 44. That is, at a high speed, the valve 36 is set to the position indicated by the two-dot chain line in FIGS. Also, at low speeds, the valves 36 are each set to the position indicated by the dashed line, and substantially delay the opening timing of the exhaust port 34. As a result, desired performance can be obtained under all operating conditions.
この実施例では、弁36の弁軸は弁軸部38とこれを挟む
軸体38A〜Ｄとで形成されるが、この弁軸の構造は種々
のものが可能であり、例えば断面多角形の軸を弁軸部38
に形成した断面同形上の挿通孔に嵌合するものなどでも
よい。In this embodiment, the valve shaft of the valve 36 is formed by a valve shaft portion 38 and shaft members 38A to 38D sandwiching the valve shaft portion. The structure of the valve shaft can be various, for example, a polygonal cross section. Shaft to valve stem 38
It may be one that fits into an insertion hole having the same cross-section formed in the above.
（発明の効果） 本発明は以上のように、各気筒の排気通路を、シリン
ダ中心を通りかつシリンダ中心面Ｄに直交する各平面
Ｅ、Ｆ、Ｇに対し同一方向に傾ける一方、排気制御弁の
弁軸をシリンダ中心面に平行としたから、隣接する気筒
の排気通路や掃気通路を干渉されることなく気筒間隔を
狭くしてエンジンの小型化を図り、また各排気制御弁の
駆動機構を非常に簡単にすることができる。また排気ポ
ートの上縁を上方へ凸としてその中央付近を最も高くす
る一方、この排気ポート上縁外側に排気制御弁の全開時
に排気制御弁の下縁が排気ポートの上縁よりも高くなる
ように進入する弁室を形成し、排気制御弁の下縁を上方
へ凸な略弧状として排気制御弁の全閉時または半開時に
排気制御弁の下縁中央付近が最も高くなるようにしたも
のであるから、排気制御弁の回動に伴い、ピストンが排
気ポートを最初に開く位置が変動する範囲が小さくな
る。このため点火栓位置や掃気・排気ポート位置、ある
いは燃料噴射方式の場合にはその噴射位置等により決ま
る好ましい掃気・排気・燃焼条件を全ての運転条件にお
いて得ることができる。(Effects of the Invention) As described above, the present invention inclines the exhaust passage of each cylinder in the same direction with respect to each of the planes E, F, and G passing through the center of the cylinder and orthogonal to the cylinder center plane D. The valve shaft is parallel to the cylinder center plane, so that the exhaust passages and scavenging passages of adjacent cylinders can be narrowed without interference between the cylinders without interference, and the drive mechanism of each exhaust control valve is Can be very easy. In addition, the upper edge of the exhaust port is made to protrude upward so that the vicinity of the center is the highest, and the lower edge of the exhaust control valve is higher than the upper edge of the exhaust port when the exhaust control valve is fully opened outside the upper edge of the exhaust port. The lower edge of the exhaust control valve is formed in a substantially arcuate shape convex upward so that the center of the lower edge of the exhaust control valve becomes highest when the exhaust control valve is fully closed or half-opened. Therefore, the range in which the position where the piston first opens the exhaust port fluctuates with the rotation of the exhaust control valve is reduced. Therefore, favorable scavenging, exhausting, and burning conditions determined by the position of the spark plug, the position of the scavenging / exhaust port, or in the case of the fuel injection system, the injection position, etc., can be obtained under all operating conditions.
第１図は本発明の一実施例である３気筒エンジンの平断
面図、第２図はそのII−II線で断面したエンジン全体の
断面図である。なお第１図は第２図におけるＩ−Ｉ線で
断面したものである。また第3A、3B、3C図は燃焼室側か
ら見た排気ポートの形状を示す図であり、第3A図は本発
明の実施例でない高速重視のものを、第3B図と第3C図は
それぞれ本発明の実施例であって中速および高速重視の
ものと低速および高速重視のものを示す。また第４図は
排気制御弁の連結構造を示す分解斜視図である。 10……シリンダボデー、32……排気通路、 34……排気ポート、36……排気制御弁、 38……弁軸部、38A〜Ｄ……軸体、 40……弁室 42……プーリ、 Ａ、Ｂ、Ｃ……シリンダ中心軸、 Ｄ……シリンダ中心面。FIG. 1 is a plan sectional view of a three-cylinder engine according to an embodiment of the present invention, and FIG. 2 is a sectional view of the entire engine taken along the line II-II. FIG. 1 is a cross-sectional view taken along the line II in FIG. 3A, 3B, and 3C are diagrams showing the shape of the exhaust port as viewed from the combustion chamber side, and FIG. 3A is for a high-speed one that is not an embodiment of the present invention, and FIGS. 3B and 3C are respectively. Embodiments of the present invention are shown with emphasis on medium speed and high speed and with emphasis on low speed and high speed. FIG. 4 is an exploded perspective view showing a connection structure of the exhaust control valve. 10 ... Cylinder body, 32 ... Exhaust passage, 34 ... Exhaust port, 36 ... Exhaust control valve, 38 ... Valve shaft part, 38A-D ... Shaft, 40 ... Valve chamber 42 ... Pulley, A, B, C: Central axis of cylinder, D: Central plane of cylinder.
───────────────────────────────────────────────────── フロントページの続き (58)調査した分野(Int.Cl.6，ＤＢ名) F02B 25/20──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. 6 , DB name) F02B 25/20
Claims (1)
心面の一側に各気筒の排気通路が互いに平行に設けら
れ、各排気通路の排気ポート上縁付近に臨んで排気ポー
トの開くタイミングを可変とする排気制御弁を備えた並
列多気筒２サイクルエンジンにおいて、 各気筒のシリンダ中心を通りかつ前記シリンダ中心面に
直交する各平面に対して、前記各排気通路を同一方向に
傾け、前記各排気制御弁の弁軸部を前記シリンダ中心面
に平行な直線上で互いに連結する一方、前記排気ポート
の上縁を上方へ凸としてその中央付近を最も高く形成す
ると共に、この排気ポートの上縁外側に前記排気制御弁
の全開時に排気制御弁の下縁が排気ポートの上縁よりも
高くなるように進入する弁室を形成し、前記排気制御弁
の排気ポートに望む下縁を上方へ凸な略弧状として排気
制御弁の全閉時または半開時に排気制御弁の下縁中央付
近が最も高くなるようにしたことを特徴とする並列多気
筒２サイクルエンジンの排気制御弁装置。An exhaust passage for each cylinder is provided in parallel with one side of a cylinder center plane including a cylinder center axis of each cylinder, and the opening timing of the exhaust port is set near the upper edge of the exhaust port of each exhaust passage. In a parallel multi-cylinder two-stroke engine provided with a variable exhaust control valve, each exhaust passage is inclined in the same direction with respect to each plane passing through the cylinder center of each cylinder and orthogonal to the cylinder center plane. The valve stems of the exhaust control valves are connected to each other on a straight line parallel to the center plane of the cylinder, while the upper edge of the exhaust port is formed to protrude upward to form the highest part near the center thereof, and the upper edge of the exhaust port is formed. On the outside, a valve chamber is formed to enter so that the lower edge of the exhaust control valve is higher than the upper edge of the exhaust port when the exhaust control valve is fully opened, and the lower edge desired for the exhaust port of the exhaust control valve is projected upward. An exhaust control valve device for a parallel two-cylinder two-stroke engine, wherein the exhaust control valve has a substantially arcuate shape, and the vicinity of the center of the lower edge of the exhaust control valve becomes highest when the exhaust control valve is fully closed or half-open.
Priority Applications (4)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1207916A JP2762122B2 (en) | 1989-08-14 | 1989-08-14 | Exhaust control valve device for parallel multi-cylinder two-cycle engine |
| US07/566,967 US5063887A (en) | 1989-08-14 | 1990-08-13 | Exhaust control valve system for parallel multi-cylinder two-cycle engine |
| EP90115602A EP0413316B1 (en) | 1989-08-14 | 1990-08-14 | Exhaust control valve system for parallel multi-cylinder two-cycle engine |
| DE69030034T DE69030034T2 (en) | 1989-08-14 | 1990-08-14 | Exhaust valve control device for a parallel multi-cylinder two-stroke engine |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1207916A JP2762122B2 (en) | 1989-08-14 | 1989-08-14 | Exhaust control valve device for parallel multi-cylinder two-cycle engine |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH0374519A JPH0374519A (en) | 1991-03-29 |
| JP2762122B2 true JP2762122B2 (en) | 1998-06-04 |
Family
ID=16547688
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP1207916A Expired - Fee Related JP2762122B2 (en) | 1989-08-14 | 1989-08-14 | Exhaust control valve device for parallel multi-cylinder two-cycle engine |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2762122B2 (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR100257949B1 (en) * | 1991-07-02 | 2000-06-01 | 톰 바스코비치 | Multicylinder two stroke cycle engine |
| JPH10274039A (en) * | 1997-03-31 | 1998-10-13 | Honda Motor Co Ltd | Two-cycle engine |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS57179327A (en) * | 1981-04-28 | 1982-11-04 | Sanshin Ind Co Ltd | Two-stroke-cycle internal-combustion engine |
| JPH01116221A (en) * | 1987-10-29 | 1989-05-09 | Honda Motor Co Ltd | Exhaust control device for two stroke cycle engine |
-
1989
- 1989-08-14 JP JP1207916A patent/JP2762122B2/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| JPH0374519A (en) | 1991-03-29 |
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| Date | Code | Title | Description |
|---|---|---|---|
| R250 | Receipt of annual fees |
Free format text: JAPANESE INTERMEDIATE CODE: R250 |
|
| LAPS | Cancellation because of no payment of annual fees |