JP2003056321A - Combustion chamber for four-stroke engine - Google Patents
Combustion chamber for four-stroke engineInfo
- Publication number
- JP2003056321A JP2003056321A JP2001246599A JP2001246599A JP2003056321A JP 2003056321 A JP2003056321 A JP 2003056321A JP 2001246599 A JP2001246599 A JP 2001246599A JP 2001246599 A JP2001246599 A JP 2001246599A JP 2003056321 A JP2003056321 A JP 2003056321A
- Authority
- JP
- Japan
- Prior art keywords
- valve
- intake
- intake valve
- combustion chamber
- exhaust
- 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
Landscapes
- Cylinder Crankcases Of Internal Combustion Engines (AREA)
Abstract
Description
【0001】[0001]
【産業上の利用分野】この発明は自動二輪車や乗用車な
ど、車両用の高性能4行程エンジンに好適な燃焼室のう
ち、シリンダヘッドに吸気通路と排気通路とを開閉する
ポペット弁を設けた、いわゆる頭上弁式のものに関す
る。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention provides a cylinder head with a poppet valve for opening and closing an intake passage and an exhaust passage in a combustion chamber suitable for a high-performance four-stroke engine for vehicles such as motorcycles and passenger cars. It relates to the so-called overhead valve type.
【0002】[0002]
【従来の技術】一般に、4行程エンジンの頭上弁式の燃
焼室は、シリンダ孔とそこに嵌挿されたピストンの頂
面、およびシリンダ孔の上部開口を閉じるシリンダヘッ
ドの下面に形成される燃焼凹部とによって形成される燃
焼空間によって構成されている。また、前記燃焼空間に
は吸気通路と排気通路とが開口させてあり、それらはそ
れぞれ吸気弁と排気弁とによって開閉可能に閉じられて
いる。そして、この形式の燃焼室は燃焼効率がよく、高
速回転が得られるため自動二輪車、あるいは乗用車用と
して慣用されている。2. Description of the Related Art Generally, an overhead valve type combustion chamber of a four-stroke engine is a combustion chamber formed on a top surface of a cylinder hole and a piston fitted therein and a bottom surface of a cylinder head that closes an upper opening of the cylinder hole. It is constituted by a combustion space formed by the recess. An intake passage and an exhaust passage are opened in the combustion space, and they are closed by an intake valve and an exhaust valve, respectively. Since this type of combustion chamber has high combustion efficiency and high-speed rotation, it is commonly used for motorcycles or passenger cars.
【0003】従来、上記頭上弁式の燃焼室では、エンジ
ンの性能を向上させるべく、燃焼室に設けた吸気弁と排
気弁とを可及的に大径に設定することが知られている
が、排気弁に比して直径の大きい吸気弁の慣性重量によ
ってエンジンの回転速度の上限が規制された。そこで、
このような不具合を解消すべく、吸気弁の数を排気弁よ
り多くした3弁式、あるいは5弁式のエンジンも提案さ
れている。また、吸排気弁を中空にして軽量化する技術
も提案されている(例えば、特開平11−315356
号公報)。Conventionally, in the above-mentioned overhead valve type combustion chamber, it is known that the intake valve and the exhaust valve provided in the combustion chamber are set to have the largest possible diameter in order to improve the performance of the engine. The upper limit of the engine speed is regulated by the inertial weight of the intake valve, which has a larger diameter than the exhaust valve. Therefore,
In order to eliminate such a problem, a three-valve or five-valve engine in which the number of intake valves is larger than that of exhaust valves has been proposed. In addition, a technique for making the intake / exhaust valve hollow to reduce the weight has been proposed (for example, JP-A-11-315356).
Issue).
【0004】また、吸気弁は吸気行程で流入する気流に
よって冷却されるが、排気弁は排気行程で既燃ガスによ
りさらに加熱される。吸気弁と排気弁との間の温度勾配
が大きく、それによりシリンダヘッドに生じる熱ひずみ
も大きくなる。Further, while the intake valve is cooled by the airflow flowing in during the intake stroke, the exhaust valve is further heated by the burnt gas during the exhaust stroke. The temperature gradient between the intake valve and the exhaust valve is large, so that the thermal strain generated in the cylinder head is also large.
【0005】[0005]
【発明が解決しようとする課題】しかしながら、吸気弁
の数を増やすについても、近年、多用されている各2個
の吸排気弁を備えた、いわゆる、4弁式の燃焼室にさら
に、1個の吸気弁を増そうとしても燃焼室の形状が扁平
になり、逆に、火炎伝播速度を低下させて出力向上の妨
げとなることがあった。また、ポペット弁のステムを中
空にしてナトリウムを充填する技術も製造コストが高い
ため、多弁式の燃焼室を構成する多数の吸排気弁に適用
することは困難であった。However, in order to increase the number of intake valves, a so-called four-valve type combustion chamber equipped with two intake and exhaust valves, which has been widely used in recent years, has a further one. Even if an attempt was made to increase the number of intake valves, the shape of the combustion chamber became flat, and conversely, the flame propagation speed was decreased, which sometimes hindered the improvement of output. Further, the manufacturing cost of the technique for filling the sodium of the poppet valve with the hollow stem is high, and thus it is difficult to apply it to a large number of intake / exhaust valves constituting a multi-valve combustion chamber.
【0006】[0006]
【課題を解決するための手段】上記した課題は、シリン
ダの内面とそこに嵌挿されたピストンの頂面、およびシ
リンダ孔の上部開口を閉じるシリンダヘッドとによって
区画して形成された燃焼空間を有し、その空間をなすシ
リンダヘッドの下面に開く吸気通路と排気通路とを吸気
弁と排気弁とによって開閉可能に閉じるとともに、前記
吸気弁と排気弁とを形成するフレア部とステム部とを薄
肉の管材によって一体的に形成し、前記吸気弁の内面を
前記燃焼空間内に開口させることによって解決できる。
そこでは、前記吸気弁はステム部側の端部が端部部材に
よって閉じられ、ステム部に連続するフレア部の端部を
燃焼室内に向けて開放させるのがよい。また、前記排気
弁はフレア部とステム部との端部を端部部材によって閉
じて中空に形成するとともに、その内部にナトリウムを
封入することが好ましい。SUMMARY OF THE INVENTION The above-mentioned problems are solved by a combustion space defined by an inner surface of a cylinder, a top surface of a piston fitted therein, and a cylinder head closing an upper opening of a cylinder hole. An intake passage and an exhaust passage that open to the lower surface of the cylinder head that forms the space are openably and closably closed by an intake valve and an exhaust valve, and a flare portion and a stem portion that form the intake valve and the exhaust valve are provided. The problem can be solved by integrally forming the thin pipe material and opening the inner surface of the intake valve into the combustion space.
In this case, it is preferable that the end portion of the intake valve on the side of the stem portion be closed by an end member, and the end portion of the flare portion continuous with the stem portion be opened toward the combustion chamber. Further, it is preferable that the exhaust valve is formed into a hollow by closing an end portion of the flare portion and the stem portion by an end member, and sodium is enclosed in the hollow portion.
【0007】[0007]
【作用】吸気弁と排気弁とは、ともにステムが管状をな
し、内部が中空であるため軽量に構成される。両弁のう
ち排気によって過熱し易い排気弁は内部にナトリウムを
詰めて伝熱性を向上させ、吸気によって冷却される吸気
弁はフレア部を通してステム部内を燃焼空間へ開放して
燃焼ガスを導入し積極的に加熱される。The intake valve and the exhaust valve both have a tubular stem and a hollow interior, so they are lightweight. Of the two valves, the exhaust valve that easily overheats due to exhaust is filled with sodium to improve heat transfer, and the intake valve that is cooled by intake opens the inside of the stem to the combustion space through the flare and actively introduces combustion gas. Is heated.
【0008】[0008]
【発明の実施の態様】以下、本願発明の実施の一形態を
説明する。図1中、10はこの発明に係る4行程エンジ
ンである。4行程エンジン10は燃焼室11を有する。
燃焼室11はシリンダブロック12に形成されたシリン
ダ孔13と、そこへ摺動可能に嵌挿されたピストン1
4、およびシリンダ孔13の端部を閉じるシリンダヘッ
ド15とによって囲まれた伸縮可能な燃焼空間をなして
いる。BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will be described below. In FIG. 1, 10 is a four-stroke engine according to the present invention. The four-stroke engine 10 has a combustion chamber 11.
The combustion chamber 11 has a cylinder hole 13 formed in a cylinder block 12 and a piston 1 slidably fitted therein.
4 and a cylinder head 15 that closes the end of the cylinder hole 13 forms an expandable and contractible combustion space.
【0009】前記シリンダヘッド15の下面には燃焼室
11の壁面をなす燃焼凹部15aが形成されている。そ
の燃焼凹部15aには吸気通路16と、排気通路17と
が開口しており、それら通路16、17の開口は、吸気
弁18と排気弁19とによってそれぞれ開閉可能に閉じ
られている。On the lower surface of the cylinder head 15, there is formed a combustion recess 15a forming a wall surface of the combustion chamber 11. An intake passage 16 and an exhaust passage 17 are opened in the combustion concave portion 15a, and the openings of the passages 16 and 17 are openably and closably closed by an intake valve 18 and an exhaust valve 19, respectively.
【0010】吸気弁18と排気弁19とは、図3、図4
で示すように、それぞれステンレス材を塑性加工して作
られた薄肉の管材からなるステム部21と、その一端に
一体的に形成された傘状のフレア部22とを有し、その
フレア部22の周縁外面に円錐面からなる弁部23が形
成されている。24は弁座24であり、前記弁部23を
着座させるべくシリンダヘッド15に焼き嵌めして固定
してある。The intake valve 18 and the exhaust valve 19 are shown in FIGS.
As shown in FIG. 3, each has a stem portion 21 made of a thin pipe material formed by plastically working a stainless material, and an umbrella-shaped flare portion 22 integrally formed at one end thereof. A valve portion 23 formed of a conical surface is formed on the outer surface of the peripheral edge of the. Reference numeral 24 denotes a valve seat 24, which is shrink-fitted and fixed to the cylinder head 15 to seat the valve portion 23.
【0011】ステム部21の他端には軸状の端部部材2
5が嵌合され摩擦溶接して固定してある。端部部材25
にはコッタ溝が形成されており、吸気弁18と排気弁1
9とは従来と同様に弁コッタ26を介してリテーナ27
に連結され、このリテーナ27を介して弁バネ28によ
り閉じ方向へ付勢されている。29は動弁カムである。
なお、排気弁19についてはフレア部22の燃焼空間側
端面が端板31によって閉じられ、内部にナトリウムが
封入されている。At the other end of the stem portion 21, a shaft-shaped end member 2 is provided.
5 are fitted and fixed by friction welding. End member 25
A cotter groove is formed in the intake valve 18 and the exhaust valve 1
9 is a retainer 27 via a valve cotter 26 as in the conventional case.
, And is urged in the closing direction by a valve spring 28 via the retainer 27. Reference numeral 29 is a valve operating cam.
Regarding the exhaust valve 19, an end surface of the flare portion 22 on the combustion space side is closed by an end plate 31, and sodium is enclosed inside.
【0012】上記態様で実施される燃焼室11には、シ
リンダヘッド15の下面が管状に作られたステム部21
から弁部23を設けたフレア部22へ至る間が薄板状に
作られた吸気弁18と、ナトリウムを封入した中空弁か
らなる排気弁19によって構成される。よって、吸気弁
18が従来のポペット弁やナトリウム封入形の中空弁に
比して一層軽量であり、慣性重量を増すことなく大径と
することができている。また、フレア部22もステム部
21に続く板状に作られているから、燃焼熱によって温
度が上がりやすくなり、本来的に高温となる排気弁19
との間の温度勾配が少なくなる。In the combustion chamber 11 implemented in the above-described mode, the lower portion of the cylinder head 15 has a tubular stem portion 21.
From the flare portion 22 provided with the valve portion 23 to the flare portion 22 is constituted by an intake valve 18 formed in a thin plate and an exhaust valve 19 formed of a hollow valve enclosing sodium. Therefore, the intake valve 18 is lighter than the conventional poppet valve and the sodium-filled hollow valve, and can have a large diameter without increasing the inertial weight. Further, since the flare portion 22 is also formed in a plate shape following the stem portion 21, the temperature is likely to rise due to combustion heat, and the exhaust valve 19 that is naturally high in temperature is generated.
There is less temperature gradient between and.
【0013】さらに排気弁19は、ナトリウム封入形中
空弁であるから、伝熱性のよいナトリウムの特性を利用
して軽量に作られている。Further, since the exhaust valve 19 is a hollow sodium valve, the exhaust valve 19 is made light by utilizing the characteristic of sodium having good heat conductivity.
【0014】次に、4行程エンジン10が運転される
と、ピストン14の下降に伴い、まず、吸気弁18が開
いて吸気通路16から吸気が流入する。ピストン14が
反転上昇すると燃焼室11内の吸気は圧縮され、その一
部は吸気弁18のフレア部22を通してステム部21へ
進入する。Next, when the four-stroke engine 10 is operated, as the piston 14 descends, first, the intake valve 18 opens and intake air flows from the intake passage 16. When the piston 14 reverses and rises, the intake air in the combustion chamber 11 is compressed, and a part thereof enters the stem portion 21 through the flare portion 22 of the intake valve 18.
【0015】圧縮された吸気が点火栓により着火される
と、吸気中の燃料が爆発的に燃焼して燃焼室11内の圧
力が急上昇するから、ピストン14は高圧の燃焼ガスの
作用を受けて下方へ押し下げられる。この燃焼行程中、
高熱の燃焼ガスは吸気弁18と排気弁19に接触し加熱
させるとともに、前記フレア部22とステム部21へ進
入した一部の吸気に含まれる燃料も燃焼し加熱するほ
か、両弁18、19は燃焼室11内の高熱を受けて加熱さ
れる。When the compressed intake air is ignited by the spark plug, the fuel in the intake air explosively burns and the pressure in the combustion chamber 11 rises sharply. Therefore, the piston 14 receives the action of high-pressure combustion gas. It is pushed down. During this combustion process,
The combustion gas of high heat comes into contact with the intake valve 18 and the exhaust valve 19 to heat them, and at the same time, the fuel contained in a part of the intake air that has entered the flare portion 22 and the stem portion 21 also burns and heats. Are heated by the high heat in the combustion chamber 11.
【0016】ピストン14が上昇に転じ排気弁19が開
いて排気行程が始まると、既燃ガスが排気通路17へ流
出する。この間、排気弁19は流動する既燃ガスの中に
あるため高熱に加熱されるが、伝熱性の優れたナトリウ
ムの作用で良好に冷却され、過熱から保護される。ま
た、吸気弁18は引き続く吸気行程中、流入する気流に
よって冷却されるため高温状態が長く保持されることは
なく、同様に過熱から保護される。このように、エンジ
ンの高出力化を図るとともに、吸気弁と排気弁の温度勾
配を減ずることができるから、熱移動は減少し熱効率が
向上する。When the piston 14 goes up and the exhaust valve 19 opens to start the exhaust stroke, the burned gas flows into the exhaust passage 17. During this time, the exhaust valve 19 is heated to high heat because it is in the flowing burnt gas, but it is well cooled by the action of sodium having excellent heat conductivity and is protected from overheating. Further, since the intake valve 18 is cooled by the inflowing airflow during the subsequent intake stroke, the high temperature state is not maintained for a long time and is similarly protected from overheating. Thus, the engine output can be increased and the temperature gradient between the intake valve and the exhaust valve can be reduced, so that the heat transfer is reduced and the thermal efficiency is improved.
【0017】[0017]
【発明の効果】請求項1の発明によれば、4行程エンジ
ンの最大回転速度を高く設定することができ、かつ高出
力運転しても吸排気弁の過熱がない。請求項2の発明に
よれば、吸気弁はステム部に続くフレア部が板状をなし
ているから軽量に作られる他、熱容量が小さくなり排気
弁との間の温度勾配が少なくなるからシリンダヘッドの
熱ひずみを少なくすることができる。請求項3の発明に
よれば、排気弁をナトリウム封入の中空形としたから、
軽量でかつ、放熱がよくすぐれた耐久性が得られる。な
どの効果がある。According to the first aspect of the present invention, the maximum rotation speed of the four-stroke engine can be set high, and the intake / exhaust valve is not overheated even at high output operation. According to the invention of claim 2, since the flare portion following the stem portion has a plate shape, the intake valve is made lightweight, and the heat capacity becomes small and the temperature gradient between the intake valve and the exhaust valve becomes small, so that the cylinder head is made. The thermal strain of can be reduced. According to the invention of claim 3, since the exhaust valve is a hollow type with sodium sealed,
It is lightweight and has good heat dissipation and excellent durability. And so on.
【図1】本願発明の一実施態様を示す4行程エンジンの
要部を示すもので、図2中のI−I断面相当の断面図で
ある。1 is a cross-sectional view showing a main part of a four-stroke engine showing an embodiment of the present invention, and is a cross-sectional view corresponding to a cross-section taken along line I-I in FIG. 2;
【図2】図1中のII−II断面図である。FIG. 2 is a sectional view taken along line II-II in FIG.
【図3】吸気弁の一部を断面した側面図である。FIG. 3 is a side view in which a part of an intake valve is sectioned.
【図4】排気弁の一部を断面した側面図である。FIG. 4 is a side view in which a part of an exhaust valve is sectioned.
10・・・・4行程エンジン 11・・・・燃焼室 12・・・・シリンダブロック 13・・・・シリンダ孔 14・・・・ピストン 15・・・・シリンダヘッド 15a・・・燃焼凹部 16・・・・吸気通路 17・・・・排気通路 18・・・・吸気弁 19・・・・排気弁 21・・・・ステム部 22・・・・フレア部 23・・・・弁部 24・・・・弁座 25・・・・端部部材 26・・・・弁コッタ 27・・・・リテーナ 28・・・・弁バネ 29・・・・動弁カム 30・・・・端板 10 ... 4 stroke engine 11 ... Combustion chamber 12 ... Cylinder block 13 ... Cylinder hole 14 ... Piston 15 ... Cylinder head 15a ... Burning recess 16 ... Intake passage 17 ... Exhaust passage 18 ... Intake valve 19 ... Exhaust valve 21 ... ・ Stem part 22 ... Flare section 23 ... Valve 24 ... 25 ... End members 26 ... Valve cotter 27 ... Retainer 28 ... Valve spring 29 ... Valve cam 30 ... End plates
───────────────────────────────────────────────────── フロントページの続き Fターム(参考) 3G024 AA02 AA06 AA14 AA15 DA01 DA03 DA06 DA10 DA18 FA03 FA13 ─────────────────────────────────────────────────── ─── Continued front page F term (reference) 3G024 AA02 AA06 AA14 AA15 DA01 DA03 DA06 DA10 DA18 FA03 FA13
Claims (3)
ンの頂面、およびシリンダ孔の上部開口を閉じるシリン
ダヘッドとによって区画して形成された燃焼空間を有
し、その空間をなすシリンダヘッドの下面に開く吸気通
路と排気通路とを吸気弁と排気弁とによって開閉可能に
閉じるとともに、前記吸気弁と排気弁とを形成するフレ
ア部とステム部とを薄肉の管材によって一体的に形成
し、前記吸気弁の内面を前記燃焼空間内に開口させてな
る4行程エンジンの燃焼室。1. A cylinder head having a combustion space defined by an inner surface of a cylinder, a top surface of a piston fitted therein, and a cylinder head closing an upper opening of a cylinder hole, and forming the space. The intake passage and the exhaust passage open to the lower surface of the are closed so as to be openable and closable by the intake valve and the exhaust valve, and the flare portion and the stem portion forming the intake valve and the exhaust valve are integrally formed by a thin pipe material. , A combustion chamber of a four-stroke engine in which the inner surface of the intake valve is opened into the combustion space.
側の端部が端部部材によって閉じられ、ステム部に連続
するフレア部の端部を燃焼室内に向けて開放させてなる
4行程エンジンの燃焼室。2. The four-stroke engine according to claim 1, wherein the intake valve has a stem-side end closed by an end member, and an end of a flare continuous with the stem is opened toward the combustion chamber. Engine combustion chamber.
とステム部との端部を端部部材によって閉じて中空に形
成するとともに、その内部にナトリウムを封入してなる
4行程エンジンの燃焼室。3. The combustion system for a four-stroke engine according to claim 1, wherein the exhaust valve is formed by closing the ends of the flare portion and the stem portion with end members to form a hollow and enclosing sodium therein. Room.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP2001246599A JP2003056321A (en) | 2001-08-15 | 2001-08-15 | Combustion chamber for four-stroke engine |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP2001246599A JP2003056321A (en) | 2001-08-15 | 2001-08-15 | Combustion chamber for four-stroke engine |
Publications (1)
Publication Number | Publication Date |
---|---|
JP2003056321A true JP2003056321A (en) | 2003-02-26 |
Family
ID=19076111
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
JP2001246599A Pending JP2003056321A (en) | 2001-08-15 | 2001-08-15 | Combustion chamber for four-stroke engine |
Country Status (1)
Country | Link |
---|---|
JP (1) | JP2003056321A (en) |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2006233910A (en) * | 2005-02-25 | 2006-09-07 | Toyota Motor Corp | Valve gear of internal combustion engine |
-
2001
- 2001-08-15 JP JP2001246599A patent/JP2003056321A/en active Pending
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2006233910A (en) * | 2005-02-25 | 2006-09-07 | Toyota Motor Corp | Valve gear of internal combustion engine |
JP4513598B2 (en) * | 2005-02-25 | 2010-07-28 | トヨタ自動車株式会社 | Valve mechanism of internal combustion engine |
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