JPS60219413A - Blow-bye preventive device of two-cycle engine - Google Patents

Blow-bye preventive device of two-cycle engine

Info

Publication number
JPS60219413A
JPS60219413A JP59077018A JP7701884A JPS60219413A JP S60219413 A JPS60219413 A JP S60219413A JP 59077018 A JP59077018 A JP 59077018A JP 7701884 A JP7701884 A JP 7701884A JP S60219413 A JPS60219413 A JP S60219413A
Authority
JP
Japan
Prior art keywords
engine
exhaust port
blow
bye
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.)
Granted
Application number
JP59077018A
Other languages
Japanese (ja)
Other versions
JPH0550573B2 (en
Inventor
Kazuyoshi Sano
一義 佐野
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.)
Yamaha Motor Co Ltd
Original Assignee
Yamaha Motor 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 Yamaha Motor Co Ltd filed Critical Yamaha Motor Co Ltd
Priority to JP59077018A priority Critical patent/JPS60219413A/en
Publication of JPS60219413A publication Critical patent/JPS60219413A/en
Publication of JPH0550573B2 publication Critical patent/JPH0550573B2/ja
Granted legal-status Critical Current

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
    • F02B25/00—Engines characterised by using fresh charge for scavenging cylinders
    • F02B25/20—Means for reducing the mixing of charge and combustion residues or for preventing escape of fresh charge through outlet ports not provided for in, or of interest apart from, subgroups F02B25/02 - F02B25/18
    • 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)
  • Characterised By The Charging Evacuation (AREA)
  • Output Control And Ontrol Of Special Type Engine (AREA)

Abstract

PURPOSE:To prevent blow-bye action of an engine further improve its scavenging efficiency, by providing a valve, whose protruded distance is controlled, in the bottom edge of an exhaust port of the two-cycle engine so as to control an opening area of the exhaust port in accordance with an operational condition of the engine. CONSTITUTION:A two-cycle engine, having in its cylinder 1 an air intake port 3, scavenging port 5 and an exhaust port 4, provides a swivellable control valve 8 in a bottom edge of the exhaust port 4. An actuator, not shown in the drawing, turns the control valve 8, controlling its turning degree by a control device assisted by a microcomputer in accordance with an engine speed or the like. When the engine is driven at a low speed, a blow-bye preventive device prevents the engine from causing its blow-bye action by increasing the turning degree of the control valve 8 so as to protrude its end 4a in a large distance and decrease an opening area of the exhaust port. And the device promotes the improvement of scavenging efficiency by decreasing a protruding distance in the end 4a of the valve 8 and increasing the opening area of the exhaust port in accordance with an increase of the engine speed.

Description

【発明の詳細な説明】 「産業上の利用分野」 この発明は、ユサイクルエンジンの吹抜は防止装置に関
する。DETAILED DESCRIPTION OF THE INVENTION "Field of Industrial Application" The present invention relates to a blow-out prevention device for a U-cycle engine.

［従来技術」 ユサイクルエンジンには、シリンダの内周壁にピストン
によって開閉される排気〇七掃気Ｏが形成されている。[Prior Art] In the U-cycle engine, an exhaust gas (07) and a scavenging air (0) are formed on the inner circumferential wall of the cylinder, which are opened and closed by a piston.

掃気Ｏかも送り込まれる新気により既燃ガスを排気０か
も排出せんとするものがある。There is also a scavenging system that uses fresh air to be sent in to exhaust burned gas.

この種の２サイクルエンジンにあつては、掃気の際に新
気の一部が排気口から排出される吹抜けが発生するので
、排気口縁部には従来から、制御弁を設けて排気Ｏの開
Ｏ面横を可変とし、吹抜ける新気量の軽減をせ九として
いる　（たとえば実公昭５６−５４１３３６号公報）。In this type of two-stroke engine, a blow-by occurs in which part of the fresh air is discharged from the exhaust port during scavenging, so a control valve has traditionally been provided at the edge of the exhaust port to control exhaust O. The side of the opening O surface is made variable to reduce the amount of fresh air flowing through (for example, Publication of Utility Model Publication No. 56-541336).

しかしながら、従来のこの種の制御弁は排気口上縁に設
け、エンジン回転数が低い場合には、この弁の先端を下
縁側に突出することにより行うものである。However, this type of conventional control valve is provided at the upper edge of the exhaust port, and when the engine speed is low, the tip of the valve is protruded toward the lower edge.

従りて、排気口の開口面積を調整する機能は果すものの
、エンジンの圧縮ストローク長さもこれに伴うで変化す
ることになり、その結果、エンジンの借速回転時は圧縮
比が大きくなり、高出力が望まれるエンジンの高回転時
は圧縮比が小さくなる。Therefore, although it functions to adjust the opening area of the exhaust port, the compression stroke length of the engine also changes accordingly, and as a result, when the engine is running at borrow speed, the compression ratio increases and the When the engine rotates at high speeds where output is desired, the compression ratio becomes smaller.

一般に、エンジンの最高出力の向上を図る場合、圧縮比
を高く設定することは一つの手段であるが、このような
場合、この構成によると、エンジンが肩口 高出力を生じる場番転時の圧縮比が低回転時の圧、　縮
比に左右され、あまり高められず不利である。Generally, one way to improve the maximum output of an engine is to set a high compression ratio. The ratio depends on the pressure and compression ratio at low revolutions, which is disadvantageous as it cannot be increased much.

「発明の目的」 この発明は、このような事情により為されたもので、こ
の種のユサイクルエンジンぜこお（Ｓて、前述の圧縮比
の変動要因を除き９つ、新気の吹抜（すを防止すること
を目的とする。``Purpose of the Invention'' This invention was made under these circumstances, and it has been found that this type of U-cycle engine (S) has nine factors, excluding the aforementioned compression ratio fluctuation factors, and a new air vent ( The purpose is to prevent

「発明の構成」 この目的は、この種のユサイクｌレニンジンの排気口の
下縁に制御弁を配置することζこより達成できる。``Structure of the Invention'' This object can be achieved by arranging a control valve at the lower edge of the exhaust port of this type of Ucycl Rengin.

「実施例」 以下、この発明のクランク室予圧縮式ユサイクルエンジ
ンにおける実施例を図面により説明スル・１はシリンダ
、２はピストンである。シ＋７ンダ１の内周壁には吸気
口３．排気口４．掃気口５力（それぞれ開口されている
。Embodiments Hereinafter, embodiments of a crank chamber precompression type U-cycle engine of the present invention will be explained with reference to the drawings. 1 is a cylinder, and 2 is a piston. The inner peripheral wall of the cylinder +7 cylinder 1 has an intake port 3. Exhaust port 4. 5 scavenging ports (each opened.

第１図は、ピストン２が下死点に位置する状態を示し、
同図中仮想線Ｘで示す上死点までの間をピストン２が往
復動するに伴い、これらの開口（まピストン２の側面に
より開閉される。吸気０３１ま気化ｕ６を経る吸気通路
の末端の開口であって、混合気（新気）をエンジンに供
給する。この実施例では、図示の下死点の位置からピス
トン２が上動して開口したとき、ピストン２の下方の空
間を経て、図示しないクランク室内に流入し、ピストン
２の下動に伴ってクランク室内の新気は予圧縮される。FIG. 1 shows a state in which the piston 2 is located at the bottom dead center,
As the piston 2 reciprocates up to the top dead center indicated by the virtual line X in the figure, these openings (are opened and closed by the side surface of the piston 2). It is an opening and supplies air-fuel mixture (fresh air) to the engine.In this embodiment, when the piston 2 moves upward from the bottom dead center position shown in the figure and opens, it passes through the space below the piston 2. Fresh air flows into a crank chamber (not shown) and is precompressed as the piston 2 moves downward.

ピストン２の上死点からの下動に伴い、まず排気０４が
開口し、ここから高圧の既燃ガスの排出が開始する。次
いで掃気口５が開０し、図示しないクランク室で予圧縮
された新気が掃気通路７を経で掃気口５かもシリンダー
内に流入しく図中矢印Ａ）、この流入した新気が既燃か
スをシリンダ外に押し出す。この場合、第１■に矢印（
Ｂ’　）で示すように流入した新気の一部は大きく開い
た排気口４かもシリンダ外に流出して、いわゆる吹抜に けが生じる。特に、ニシジン回転が低速の場合、排気０
４が開放している時間が長くなるので、シリンダー内に
流入した新気に対する吹抜は量の割合が多くなる。As the piston 2 moves downward from the top dead center, the exhaust 04 first opens, and the high-pressure burnt gas begins to be discharged from there. Next, the scavenging port 5 opens, and fresh air precompressed in the crank chamber (not shown) flows into the cylinder via the scavenging passage 7 (arrow A in the figure), and this fresh air flows into the cylinder after being burned. Push the scum out of the cylinder. In this case, the first ■ is the arrow (
As shown in B'), a portion of the fresh air flowing in flows out of the cylinder through the widely opened exhaust port 4, causing damage to the so-called atrium. In particular, when the rotation speed is low, the exhaust gas is 0.
4 is open for a longer period of time, the ratio of the amount of air vented to the fresh air flowing into the cylinder increases.

そのため、この実施例では本発明の８着に基づき次に述
べるように吹抜は防止装置を構成してなる。Therefore, in this embodiment, based on the eighth aspect of the present invention, the atrium constitutes a prevention device as described below.

８は揺動弁で、排気０４の下縁４ａに沿わせて配置し、
排気口下縁４ａからの揺動弁８の上方への突出によつて
、前述の吹抜けを軽減するも・ので、本発明でいう制御
弁に該当する。この揺動弁８は次のように駆動されて排
気口下縁４ａからの突出量（図示Ｌ）が調整されて新気
の吹抜は防止を行う。8 is a swing valve, arranged along the lower edge 4a of the exhaust 04,
The upward protrusion of the swinging valve 8 from the lower edge 4a of the exhaust port reduces the above-mentioned blow-through, and thus corresponds to a control valve in the present invention. The swing valve 8 is driven as follows to adjust the amount of protrusion from the lower edge 4a of the exhaust port (L in the figure) to prevent fresh air from blowing out.

１１はタコメータなどのエンジンの回転速度センサ、１
２はマイクロコンピュータなどの制御装置ｆ〜１３はサ
ーボモータである０回転速度センサ１１かも得たエンジ
ンの回転速度信号は、制御装ｆｆ１１２に入力され、演
算されて、制御装置１２はサーボモータ１３に出力信号
を送る。11 is an engine rotational speed sensor such as a tachometer;
The engine rotational speed signal obtained from the rotational speed sensor 11 is input to the control device ff112 and calculated, and the control device 12 outputs the signal to the servomotor 13. Send output signal.

この出力信号は制御装置１またるマイクロコンピュータ
にあらかじめ記憶させたニシジン回転数と好ましい突出
量りとの関係に従うものである。This output signal is in accordance with the relationship between the rotational speed and the preferred protrusion scale, which is stored in advance in the microcomputer included in the control device 1.

サーボモータ１３は、この制御装置１２の出力信号によ
り適宜駆動する七、揺動弁８はこのサーボモータ１３と
の閏をボーデンワイヤ１４により連結されているので、
揺動弁８が揺動して突出量りの調整がエンジン回転速度
に応じてなされる。The servo motor 13 is appropriately driven by the output signal of the control device 12.The swing valve 8 is connected to the servo motor 13 by a Bowden wire 14, so that
The swing valve 8 swings to adjust the amount of protrusion in accordance with the engine speed.

すなわち、エンジン回転速度が低い場合には、突出量す
を大きくすることによつて排気口４の開Ｏ面積を小さく
して新気の吹抜けを防止し、エンジン回転速度が高い場
合には突出量りを小さくして排気口４の開口面積を拡大
して短時間の排気口の開すでの掃気効率の向上を図る。That is, when the engine rotation speed is low, the protrusion amount is increased to reduce the opening area of the exhaust port 4 to prevent fresh air from blowing through, and when the engine rotation speed is high, the protrusion amount is increased. The opening area of the exhaust port 4 is enlarged by reducing the size of the exhaust port 4, thereby improving the scavenging efficiency when the exhaust port is opened for a short time.

モして、このとき、揺動弁８が排気口４の下縁４ａに沿
つて配置されており１締４ｂには殴けられていないので
、この揺動弁８の突出量ムの変化は圧縮比には影響しな
い。At this time, since the swing valve 8 is arranged along the lower edge 4a of the exhaust port 4 and is not punched by the first clamp 4b, the change in the protrusion amount of the swing valve 8 is Does not affect compression ratio.

尚、以上説明した実施例では制御弁として揺動弁８を用
いたものであるが、本発明ではこれに限らず、たとえば
摺動弁等の他の形式のものでありでもよい。In the embodiment described above, the swing valve 8 is used as the control valve, but the present invention is not limited to this, and other types such as a slide valve may be used.

「発明の効果」 この発明は、以上説明したように、排気口の開０面積を
調整する制御弁を排気Ｏの下縁に沿わせで配置したもの
である。従つて、この制御弁による排気口の開口面ＭＲ
調整は、エンジンの圧縮比を決定する排気口の１峰位置
の変動を来たさず行われ〜圧縮比の変動要因を除去して
新気の吹抜けを防止することができる。"Effects of the Invention" As explained above, in the present invention, a control valve for adjusting the open area of the exhaust port is arranged along the lower edge of the exhaust gas. Therefore, the opening surface MR of the exhaust port by this control valve
The adjustment is performed without causing a change in the peak position of the exhaust port, which determines the compression ratio of the engine, and it is possible to eliminate the causes of fluctuations in the compression ratio and prevent fresh air from blowing through.

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

図面は、この発明の実施例に関し、 第１図は、クランク室予圧縮式ユサイクルエンジンの縦
断面図、 第２図はＩＩ−工Ｉ矢視図、。 第３図はＸＩＸ　−ＩＩＩ矢視図である。 １・・・・シリンダ ２・・・・ピストン ４・・・・排気口 ４ａ・・下縁 ８・・・・制御弁 特許出願人　ヤマハ発動機株式会社 代　理　人　弁理士　野末　祐司 第２図 ８１３ 第３図The drawings relate to embodiments of the present invention; FIG. 1 is a longitudinal sectional view of a crank chamber precompression type Ucycle engine; FIG. 2 is a view taken along the arrow II-I; FIG. 3 is a view taken along arrows XIX-III. 1... Cylinder 2... Piston 4... Exhaust port 4a... Lower edge 8... Control valve Patent applicant Yamaha Motor Co., Ltd. Representative Patent attorney Yuji Nozue Figure 2 813 Figure 3

Claims (1)

【特許請求の範囲】[Claims] シリンダの内周壁にピストンによって開閉される排気口
を有し、この排気０にその開口面積を調整する制御弁を
設けたものにおいて、この制御弁を〜排気口の下縁に沿
わせて配置してなるコサイクルエンジンの吹抜は防止装
置。In a cylinder that has an exhaust port that is opened and closed by a piston on the inner circumferential wall of the cylinder, and a control valve that adjusts the opening area of the exhaust port is provided, this control valve is arranged along the lower edge of the exhaust port. The atrium of the cocycle engine is a prevention device.
JP59077018A 1984-04-16 1984-04-16 Blow-bye preventive device of two-cycle engine Granted JPS60219413A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP59077018A JPS60219413A (en) 1984-04-16 1984-04-16 Blow-bye preventive device of two-cycle engine

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP59077018A JPS60219413A (en) 1984-04-16 1984-04-16 Blow-bye preventive device of two-cycle engine

Publications (2)

Publication Number Publication Date
JPS60219413A true JPS60219413A (en) 1985-11-02
JPH0550573B2 JPH0550573B2 (en) 1993-07-29

Family

ID=13622013

Family Applications (1)

Application Number Title Priority Date Filing Date
JP59077018A Granted JPS60219413A (en) 1984-04-16 1984-04-16 Blow-bye preventive device of two-cycle engine

Country Status (1)

Country Link
JP (1) JPS60219413A (en)

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5627014A (en) * 1979-08-09 1981-03-16 Yamaha Motor Co Ltd Exhaust valve device of two-cycle engine

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5627014A (en) * 1979-08-09 1981-03-16 Yamaha Motor Co Ltd Exhaust valve device of two-cycle engine

Also Published As

Publication number Publication date
JPH0550573B2 (en) 1993-07-29

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