JPS61175224A - Structure of combustion chamber in two-cycle engine - Google Patents

Structure of combustion chamber in two-cycle engine

Info

Publication number
JPS61175224A
JPS61175224A JP60015101A JP1510185A JPS61175224A JP S61175224 A JPS61175224 A JP S61175224A JP 60015101 A JP60015101 A JP 60015101A JP 1510185 A JP1510185 A JP 1510185A JP S61175224 A JPS61175224 A JP S61175224A
Authority
JP
Japan
Prior art keywords
recess
combustion chamber
cylinder head
squish
piston
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
Application number
JP60015101A
Other languages
Japanese (ja)
Inventor
Toshinori Takeyama
竹山　敏範
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 JP60015101A priority Critical patent/JPS61175224A/en
Publication of JPS61175224A publication Critical patent/JPS61175224A/en
Pending legal-status Critical Current

Links

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
    • F02B23/00—Other engines characterised by special shape or construction of combustion chambers to improve operation
    • F02B23/08—Other engines characterised by special shape or construction of combustion chambers to improve operation with positive ignition
    • 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
    • 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
    • F02B2075/026—Engines characterised by their cycles, e.g. six-stroke having less than six strokes per cycle three
    • 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)
  • Combustion Methods Of Internal-Combustion Engines (AREA)

Abstract

PURPOSE:To avoid abruptly rising the pressure in an engine cylinder upon combustion to reduce the burning sound of an engine, by setting the inclination of the inner peripheral surface of a recess forming a combustion chamber which creates a squish steam. CONSTITUTION:A combustion chamber 10 is formed between the top surface of a piston 4 and the lower surface of a cylinder head 6. Further, a squish surface 12 is formed by the diametrically outside area of top surface of the piston 4 and the lower surface of the cylinder head 6 in the area opposing the former. Further, a recess 13 is formed in the lower surface of the cylinder head 6 in the area opposing the diametrically inside area of top surface of the piston 4. In this arrangement, the inclination of the inner peripheral surface of the recess 13 is set, with respect to the axis of the recess 13, at delta which is determined by the equation delta=H/{(D-d)/2}>=1, where D is the diameter of the imaginary circle which is defined by the crossing line between the lower surface of the cylinder head 6 in the squish surface 12 and the inner peripheral surface of the recess 13, (d) is the diameter of the ceiling surface of the recess 13 and H is the distance from the above-mentioned imaginary circle to the ceiling surface.

Description

【発明の詳細な説明】 （産業上の利用分野） この発明は、燃焼音を低減させるようにした自動二輪車
等に用いられる２サイクルエンジンの燃焼室構造に関す
る。DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a combustion chamber structure of a two-stroke engine used in a motorcycle or the like, which is designed to reduce combustion noise.

（従来の技術） エンジンから生じる騒音はできるだけ低い方が好ましい
。(Prior Art) It is preferable that the noise generated from the engine be as low as possible.

ところで、従来より、例えば特開昭５１−２９６２２号
公報で示されているように、２サイクルエンジンの燃焼
室は」二死点付近におけるピストン頂面とシリンダヘッ
ドの下面との間に形成されており、エンジンから生じる
騒音はこの燃焼室の構造に影響されて大きくなったり、
小さくなったりするものである。By the way, conventionally, as shown in Japanese Patent Laid-Open No. 51-29622, the combustion chamber of a two-stroke engine is formed between the top surface of the piston near the second dead center and the bottom surface of the cylinder head. , the noise generated from the engine is affected by the structure of this combustion chamber and becomes louder.
It may become smaller.

（発明が解決しようとする問題点） しかし、従来、騒音低減のための燃焼室構造の改良は十
分ではなく、特に燃焼速度を速めるためにスキッシュ流
を生じさせるようにした燃焼室の構造では燃焼音が大き
くなり、この結果、エンジンからの騒音の発生が大きく
なるという不都合がある。(Problem to be solved by the invention) However, conventional improvements in combustion chamber structures for noise reduction have not been sufficient, and in particular, combustion chamber structures that generate squish flow to increase the combustion speed There is a disadvantage that the sound becomes louder and, as a result, the noise generated from the engine becomes louder.

（発明の目的） この発明は、上記のような事情に注目してなされたもの
で、エンジンの燃焼音を低減させ、エンジンからの騒音
の発生を抑制することを目的とする。(Objective of the Invention) The present invention has been made in view of the above-mentioned circumstances, and an object of the present invention is to reduce engine combustion noise and suppress generation of noise from the engine.

（発明の構成） −１−記目的を達成するためのこの発明の特徴とすると
ころは、スキッシュ流を生じさせるようにした燃焼室を
有する２サイクルエンジンにおいて、燃焼室を形成する
凹所内周面の傾きを大きくしてシリンダ内の燃焼時の圧
力が急激に」二列しないようにした点にある。(Structure of the Invention) -1- The present invention is characterized in that, in a two-stroke engine having a combustion chamber configured to generate a squish flow, the inner circumferential surface of a recess forming the combustion chamber is The reason is that the slope of the cylinder is increased to prevent the pressure in the cylinder during combustion from suddenly increasing.

（実施例） 以下、この発明の実施例を図面により説明する。(Example) Embodiments of the present invention will be described below with reference to the drawings.

第１図から第４図は第１実施例を示している。1 to 4 show a first embodiment.

図において、１は２サイクルエンジンで、このエンジン
１のシリンダ２はシリンダブロック３と、このシリンダ
ブロック３内に挿入されるピストン４と、同」ニジリン
ダブロック３の上面に取り伺けられるシリンダヘッド６
とを有している。そして、シリンダブロック３には掃気
ポート７か形成され、ピストン４はコネクティングロッ
ド８を介して図示しないクランクシャフトに連結されて
いる。In the figure, 1 is a two-stroke engine, and the cylinder 2 of this engine 1 includes a cylinder block 3, a piston 4 inserted into the cylinder block 3, and a cylinder head that can be seen on the top surface of the cylinder block 3. 6
It has A scavenging port 7 is formed in the cylinder block 3, and the piston 4 is connected to a crankshaft (not shown) via a connecting rod 8.

上記ピストン４が」二死点付近にある場合に、このピス
トン４の頂面とシリンダヘッド６の下面とで燃焼室１０
が形成される。そして、この燃焼室１０に臨むようにシ
リンダヘンドロに点火プラグ１１が取り付けられる。When the piston 4 is near the second dead center, the combustion chamber 10 is formed between the top surface of the piston 4 and the bottom surface of the cylinder head 6.
is formed. A spark plug 11 is attached to the cylinder cylinder so as to face this combustion chamber 10.

上記シリンダ２内での混合気の流動を促進して燃焼速度
を速くさせるために、−上記燃焼室１０は圧縮行程にお
けるピストン運動によってスキッシュ流を生じさせる構
造とされる。In order to promote the flow of the air-fuel mixture within the cylinder 2 and increase the combustion speed, the combustion chamber 10 is structured to generate a squish flow by piston movement during the compression stroke.

即ち、上死点付近におけるピストン４頂面の径方向外部
側との面と、この面に対面するシリンダヘッド６下面と
で間隙の狭いスキッシュ面１２が形成される。また、同
上ピストン４頂面の径方向内部側の面に対面するシリン
ダヘッド６下面に平面断面が円形の凹所１３が形成され
る。That is, a squish surface 12 with a narrow gap is formed between the radially outer surface of the top surface of the piston 4 near the top dead center and the lower surface of the cylinder head 6 facing this surface. Further, a recess 13 having a circular planar cross section is formed on the lower surface of the cylinder head 6 facing the radially inner surface of the top surface of the piston 4 .

そして、圧縮行程においてピストン４が」−昇するとき
、スキッシュ面１２で圧縮された混合気が凹所１３内に
向って勢いよく押し出され（第２図中矢印Ａ）、凹所１
３内での混合気の流動が促進されて燃焼速度が速められ
る。When the piston 4 moves upward during the compression stroke, the air-fuel mixture compressed by the squish surface 12 is forcefully pushed out into the recess 13 (arrow A in FIG. 2), and
The flow of the air-fuel mixture within the combustion chamber 3 is promoted and the combustion rate is increased.

４−記構成において、凹所１３の軸方向に対するその内
周面１３ａの傾き（δ）は第１図を参照して、 として示される。4- In the configuration described above, the inclination (δ) of the inner circumferential surface 13a of the recess 13 with respect to the axial direction is shown as follows with reference to FIG.

但し、」−記りはスキッシュ面１２におけるシリンダヘ
ッド６下面の仮想延長面と、凹所１３の内周面１３ａの
仮想延長面との交線により形成される仮想円の直径とさ
れる。However, "-" is the diameter of an imaginary circle formed by the intersection line of the imaginary extension surface of the lower surface of the cylinder head 6 on the squish surface 12 and the imaginary extension surface of the inner peripheral surface 13a of the recess 13.

また、」二記ｄは凹所１３の天井面１３ｂの直径とされ
、Ｈは上記仮想円から天井面１３ｂに至るまでの長さと
されている。Furthermore, d is the diameter of the ceiling surface 13b of the recess 13, and H is the length from the virtual circle to the ceiling surface 13b.

そして、」−記凹所１３の内周面１３ａはその傾き（δ
）が　１．８以上となるように形成される。The inner circumferential surface 13a of the recess 13 has an inclination (δ
) is 1.8 or more.

即ち、δ≧　１．８とされる。That is, δ≧1.8.

第４図は燃焼室１０に関する第２実施例を示している。FIG. 4 shows a second embodiment of the combustion chamber 10.

図中凹所１３の内周面１３ａはその軸方向断面が円弧面
に形成され、この円弧面の中心は上記仮想円のほぼ中心
点−Ｉ−とされ、その円弧面の半径はＲで示されている
。The inner circumferential surface 13a of the recess 13 in the figure has an axial cross section formed into an arcuate surface, the center of this arcuate surface is approximately the center point -I- of the virtual circle, and the radius of the arcuate surface is indicated by R. has been done.

そして、この場合、Ｄ≧２Ｒであれば、とされる。In this case, if D≧2R.

他の構成は第１実施例と同様である。The other configurations are the same as in the first embodiment.

第５図は燃焼室１０に関する第３実施例を示している。FIG. 5 shows a third embodiment of the combustion chamber 10.

図中凹所１３の内周面１３ａはその断面が円弧面に形成
され、この円弧面の中心は天井面１３ｂから寸法り下っ
た位置とされている。In the figure, the inner circumferential surface 13a of the recess 13 has an arcuate cross section, and the center of the arcuate surface is located at a position below the ceiling surface 13b.

そして、この場合、Ｄ＜２Ｒであれば、として、δ≧　
１．８とすることがより好ましい。In this case, if D<2R, then δ≧
It is more preferable to set it to 1.8.

他の構成は第２実施例と同様である。The other configurations are the same as in the second embodiment.

第６図から第８図は」二記傾き（δ）を３．１３にした
場合（図中実線図示）と、０，８２にした場合（図中点
線図示）とを比較した実測値のグラフ図である。Figures 6 to 8 are graphs of actual measured values comparing the slope (δ) of 3.13 (shown by the solid line in the figure) and 0.82 (shown by the dotted line in the figure). It is a diagram.

第６図においぞ、クランク角度に対するシリンダ内圧の
変化には両者にほとんど差異はみられない。また、第７
図におけるＰ−ｖ線図においても　。In FIG. 6, there is almost no difference in the change in cylinder internal pressure with respect to the crank angle. Also, the seventh
Also in the P-v diagram in the figure.

両者にほとんど差異はなく、よって、傾き（δ）をδ≧
　１．８の範囲にしてもエンジン性能が低下するという
不都合はない。There is almost no difference between the two, so the slope (δ) is δ≧
Even if it is in the range of 1.8, there is no inconvenience that the engine performance deteriorates.

第８図において、クランク角度が上死点付近にあるとき
の圧力上昇率は傾き（δ）を３．１３にした方が相当低
くなり、これによって燃焼音が低減される。In FIG. 8, the pressure increase rate when the crank angle is near top dead center is considerably lower when the slope (δ) is set to 3.13, thereby reducing combustion noise.

第９図は傾き（δ）を種々に設定した場合におけるエン
ジン騒音の実測値を示したもので、これによれば、傾き
（δ）を１．８以−ヒにするとエンジンの騒音が急激に
低下する。Figure 9 shows the actual measured values of engine noise when the slope (δ) is set variously. According to this figure, when the slope (δ) is set to 1.8 or more, the engine noise suddenly increases. descend.

なお、この場合のエンジン１は排気量が５０ｃｃの単気
筒でエンジン回転数は５０００ｒ、ｐ、ｍであり、測定
位置をシリンダ２の側方５０＋ｎｍとしたものである。Note that the engine 1 in this case is a single cylinder with a displacement of 50 cc, the engine rotational speed is 5000 r, p, m, and the measurement position is 50+nm to the side of the cylinder 2.

（発明の効果） この発明によれば、スキッシュ流を生じさせる燃焼室を
有する２サイクルエンジンにおいて、凹所の内周面の傾
きが１．８以上とされてシリンダ内の燃焼時の圧力が急
激に上昇しないようにされたため、この燃焼音が低減さ
れ、よって、エンジンからの騒音の発生が抑制される。(Effects of the Invention) According to the present invention, in a two-stroke engine having a combustion chamber that generates a squish flow, the slope of the inner circumferential surface of the recess is set to be 1.8 or more, so that the pressure during combustion in the cylinder suddenly increases. Since the combustion noise is prevented from increasing, this combustion noise is reduced, and the generation of noise from the engine is thereby suppressed.

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

図はこの発明の実施例を示し、第１図から第３図は第１
実施例で第１図は燃焼室の簡略断面図、第２図はシリン
ダの側面断面図、第３図は第２図の■−ｍ線矢視図、第
４図は第２実施例を示す燃焼室の簡略断面図、第５図は
第３実施例を示す燃焼室の簡略断面図、第６図から第９
図は各種実測イ（白を示すグラフ図である。 １φ争エンジン、２＠・シリンダ゛、４・・ピストン、
６拳・シリンダヘッド、１０・・燃焼室、１２・・スキ
ッシュ面、１３−・凹所、１３ａ・・内周面、１３ｂ・
・天井面。The figures show embodiments of the invention, and Figures 1 to 3 are
In the example, Fig. 1 is a simplified sectional view of the combustion chamber, Fig. 2 is a side sectional view of the cylinder, Fig. 3 is a view taken along the line ■-m in Fig. 2, and Fig. 4 shows the second embodiment. A simplified sectional view of the combustion chamber, FIG. 5 is a simplified sectional view of the combustion chamber showing the third embodiment, and FIGS. 6 to 9
The figure is a graph showing various actual measurements (white). 1φ engine, 2 cylinders, 4 pistons,
6. Cylinder head, 10. Combustion chamber, 12. Squish surface, 13. Recess, 13a. Inner peripheral surface, 13b.
・Ceiling surface.

Claims (1)

【特許請求の範囲】 １、上死点付近におけるピストン頂面の径方向外部側の
面と、この面に対面するシリンダヘッド下面とでスキッ
シュ面を形成し、かつ、同上ピストン頂面の径方向内部
側の面に対面するシリンダヘッド下面に平面断面が円形
の凹所を形成した２サイクルエンジンの燃焼室構造にお
いて、上記凹所の軸方向に対するその内周面の傾き（δ
）を、δ＝Ｈ／［（Ｄ−ｄ）／２］≧１．８ 但し、Ｄはスキッシュ面におけるシリンダヘッド下面の
仮想延長面と、凹所内周面の仮想延長面との交線により
形成される仮想円の直径、 ｄは凹所の天井面の直径、 Ｈは上記仮想円から天井面に至る長さ、 としたことを特徴とする２サイクルエンジンの燃焼室構
造。[Claims] 1. A squish surface is formed by the radially outer surface of the piston top surface near the top dead center and the lower surface of the cylinder head facing this surface, and the radial direction of the piston top surface In a two-stroke engine combustion chamber structure in which a recess with a circular planar cross section is formed on the lower surface of the cylinder head facing the inner surface, the inclination of the inner peripheral surface of the recess with respect to the axial direction (δ
), δ=H/[(D-d)/2]≧1.8 However, D is formed by the intersection line of the imaginary extension surface of the lower surface of the cylinder head on the squish surface and the imaginary extension surface of the inner peripheral surface of the recess. d is the diameter of the ceiling surface of the recess; H is the length from the virtual circle to the ceiling surface.
JP60015101A 1985-01-29 1985-01-29 Structure of combustion chamber in two-cycle engine Pending JPS61175224A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP60015101A JPS61175224A (en) 1985-01-29 1985-01-29 Structure of combustion chamber in two-cycle engine

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP60015101A JPS61175224A (en) 1985-01-29 1985-01-29 Structure of combustion chamber in two-cycle engine

Publications (1)

Publication Number Publication Date
JPS61175224A true JPS61175224A (en) 1986-08-06

Family

ID=11879445

Family Applications (1)

Application Number Title Priority Date Filing Date
JP60015101A Pending JPS61175224A (en) 1985-01-29 1985-01-29 Structure of combustion chamber in two-cycle engine

Country Status (1)

Country Link
JP (1) JPS61175224A (en)

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5851385U (en) * 1981-09-30 1983-04-07 オ−テツク電子株式会社 Tension detection type warning device

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5851385U (en) * 1981-09-30 1983-04-07 オ−テツク電子株式会社 Tension detection type warning device

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