JPH0320568B2 - - Google Patents
Info
- Publication number
- JPH0320568B2 JPH0320568B2 JP2969689A JP2969689A JPH0320568B2 JP H0320568 B2 JPH0320568 B2 JP H0320568B2 JP 2969689 A JP2969689 A JP 2969689A JP 2969689 A JP2969689 A JP 2969689A JP H0320568 B2 JPH0320568 B2 JP H0320568B2
- Authority
- JP
- Japan
- Prior art keywords
- intake
- intake valves
- sides
- valves
- camshaft
- 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
Links
- 238000002485 combustion reaction Methods 0.000 claims description 21
- 230000006835 compression Effects 0.000 description 3
- 238000007906 compression Methods 0.000 description 3
- 230000000694 effects Effects 0.000 description 1
- 230000002452 interceptive effect Effects 0.000 description 1
- 230000001360 synchronised effect Effects 0.000 description 1
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
- F01L1/00—Valve-gear or valve arrangements, e.g. lift-valve gear
- F01L1/26—Valve-gear or valve arrangements, e.g. lift-valve gear characterised by the provision of two or more valves operated simultaneously by same transmitting-gear; peculiar to machines or engines with more than two lift-valves per cylinder
- F01L1/265—Valve-gear or valve arrangements, e.g. lift-valve gear characterised by the provision of two or more valves operated simultaneously by same transmitting-gear; peculiar to machines or engines with more than two lift-valves per cylinder peculiar to machines or engines with three or more intake valves per cylinder
-
- 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
- F02B2275/00—Other engines, components or details, not provided for in other groups of this subclass
- F02B2275/18—DOHC [Double overhead camshaft]
Landscapes
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Valve-Gear Or Valve Arrangements (AREA)
- Combustion Methods Of Internal-Combustion Engines (AREA)
Description
【発明の詳細な説明】
［産業上の利用分野］
この発明は１気筒当り３つの吸気バルブと２つ
の排気バルブを有する４サイクルエンジンに関す
るものである。DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] This invention relates to a four-stroke engine having three intake valves and two exhaust valves per cylinder.
［従来の技術］
１気筒当り３つの吸気バルブ及び３つの排気バ
ルブを有し、シリンダ中央部に点火プラグを備
え、前記吸気バルブのうち中間の吸気バルブをそ
の両側の吸気バルブよりもシリンダの軸線に対す
る傾きを小さくして燃焼室に臨ませるようにした
エンジンは、例えば英国特許第296125号明細書に
示すように公知である。[Prior Art] One cylinder has three intake valves and three exhaust valves, and a spark plug is provided in the center of the cylinder, and the middle intake valve is located closer to the axis of the cylinder than the intake valves on both sides. An engine in which the combustion chamber is exposed to the engine at a small angle is known, for example, as shown in British Patent No. 296125.
また、１気筒当り３つの吸気バルブ及び２つの
排気バルブを有するエンジンも英国特許第687528
号明細書に示すように公知である。 Also, an engine with three intake valves and two exhaust valves per cylinder is covered by British Patent No. 687528.
It is publicly known as shown in the specification of No.
［発明が解決しようとする課題］
ところで、前記公知の前者のエンジンにおいて
は、１気筒当り３つの吸気バルブを該気筒の略1/
２の箇所を利用して配置しているが、シリンダ中
央部の点火プラグを中心として、吸気バルブ部と
排気バルブ部とはＶ字形に大きく開かれてそれぞ
れ独立して配置されているため、３つの吸気バル
ブの軸線とシリンダ軸線とのなす角度が大きくな
つて結果的には燃焼室容積を大きくせざるを得な
くなり、圧縮比が高められない。また、後者のエ
ンジンにおいては、吸気バルブ傘径と排気バルブ
傘径が同じであるから、点火プラグと両側の吸気
バルブが近付くことになるため、両側の吸気バル
ブを閉方向に付勢するスプリングをカム軸方向に
見てプラグタワーとオーバーラツプするように配
設すると点火プラグが必然的に小さくならざるを
得ず、従つて高出力のエンジンを得るのには不向
きである。[Problems to be Solved by the Invention] Incidentally, in the known former engine, three intake valves per cylinder are arranged at approximately 1/1/2 of the cylinder.
However, the intake valve part and exhaust valve part are widely opened in a V-shape and are arranged independently, centering on the spark plug in the center of the cylinder. The angle between the axes of the two intake valves and the cylinder axis becomes large, and as a result, the volume of the combustion chamber has to be increased, making it impossible to increase the compression ratio. In addition, in the latter engine, the diameter of the intake valve and the diameter of the exhaust valve are the same, so the spark plug and the intake valves on both sides are close to each other, so the spring that biases the intake valves on both sides in the closing direction is If the spark plug is arranged so as to overlap with the plug tower when viewed in the direction of the camshaft, the spark plug must inevitably become smaller, and is therefore unsuitable for obtaining a high-output engine.
という問題点を有していた。There was a problem.
この発明は、従来技術の有するこのような問題
点に鑑みてなされたものであり、その目的とする
ところは、吸気バルブの傾きと傘径及びスプリン
グ等の位置を適正にすることによつて、燃焼室容
積を小さくして圧縮比を高めることができる高出
力のエンジンを提供しようとするものである。 This invention was made in view of the problems of the prior art, and its purpose is to correct the inclination of the intake valve, the diameter of the valve, and the position of the spring, etc. The aim is to provide a high-output engine that can reduce the volume of the combustion chamber and increase the compression ratio.
［課題を解決するための手段］
上記目的を達成するために、この発明における
４サイクルエンジンは、
カム軸により駆動される３つの吸気バルブと２
つの排気バルブを各気筒毎に備え、これら吸排気
バルブを燃焼室の中心を通りカム軸に平行な中心
線の一側と他側に振り分けて配置し、プラグタワ
ーに囲まれた点火プラグを燃焼室の略中央に臨ま
せた４サイクルエンジンにおいて、前記吸気バル
ブのうち中間の吸気バルブを前記中心線に対して
プラグタワーの外側に、両側の吸気バルブをプラ
グタワーのカム軸方向両側に位置させ、両側の吸
気バルブのシリンダ軸線に対する傾きが中間の吸
気バルブのそれよりも大きく、かつカム軸方向に
見て両側の吸気バルブと中間の吸気バルブの軸線
の延長線が吸気バルブの上方にて交差するように
両側の吸気バルブを傾斜させ、両側の吸気バルブ
の傘径を排気バルブの傘径よりも小さくすると共
に、両側の吸気バルブを閉方向に付勢するスプリ
ングをカム軸方向に見てプラグタワーとオーバー
ラツプするように配設したことを特徴とする、
ものである。[Means for Solving the Problems] In order to achieve the above object, the four-stroke engine of the present invention has three intake valves driven by a camshaft and two intake valves driven by a camshaft.
Two exhaust valves are provided for each cylinder, and these intake and exhaust valves are distributed to one side and the other side of the center line that passes through the center of the combustion chamber and is parallel to the camshaft, and the spark plug surrounded by the plug tower burns. In a four-stroke engine facing approximately the center of the chamber, the middle intake valve among the intake valves is located outside the plug tower with respect to the center line, and the intake valves on both sides are located on both sides of the plug tower in the cam axis direction. , the inclination of the intake valves on both sides with respect to the cylinder axis is larger than that of the middle intake valve, and the extended lines of the axes of both intake valves and the middle intake valve intersect above the intake valve when viewed in the camshaft direction. The intake valves on both sides are tilted so that the diameters of the intake valves on both sides are smaller than the diameters of the exhaust valves, and the springs that bias the intake valves on both sides in the closing direction can be seen in the direction of the camshaft. It is characterized by being placed so that it overlaps with the tower.
［作用］
両側の吸気バルブの傘径を排気バルブの傘径よ
りも小さくしたので、両側の吸気バルブをカム軸
方向においてプラグタワーから離して配置するこ
とができ、また両側の吸気バルブのスプリングを
カム軸方向に見てプラグタワーとオーバーラツプ
するように配設したので、３つの吸気バルブの軸
線とシリンダ軸線とのなす角度を小さく抑えるこ
とができる。[Function] Since the diameter of the intake valves on both sides is smaller than the diameter of the exhaust valve, the intake valves on both sides can be placed away from the plug tower in the camshaft direction, and the springs of the intake valves on both sides can be Since it is arranged so as to overlap with the plug tower when viewed in the camshaft direction, the angle between the axes of the three intake valves and the cylinder axis can be kept small.
［実施例］
この発明の実施例を以下図面を参照して説明す
る。[Example] An example of the present invention will be described below with reference to the drawings.
図面は４サイクルエンジンの１気筒を示してお
り、図中ａはシリンダ、ｂはシリンダヘツド、１
は吸気通路、２は排気通路である。 The drawing shows one cylinder of a four-stroke engine, where a is the cylinder, b is the cylinder head, and 1
2 is an intake passage, and 2 is an exhaust passage.
３は前記シリンダヘツドｂ下面に形成された燃
焼室であり、吸気通路１及び排気通路２が開口し
ている。 A combustion chamber 3 is formed on the lower surface of the cylinder head b, and an intake passage 1 and an exhaust passage 2 are open therein.
４は点火プラグ取付用のネジ孔であり、前記燃
焼室３上面の中心部に開口している。 Reference numeral 4 denotes a screw hole for attaching a spark plug, which opens at the center of the upper surface of the combustion chamber 3.
５は前記吸気通路１を開閉する吸気バルブ、６
は排気通路２を開閉する排気バルブである。 5 is an intake valve that opens and closes the intake passage 1; 6;
is an exhaust valve that opens and closes the exhaust passage 2.
これら排気バルブ５及び排気バルブ６は夫々そ
の下端の傘部が燃焼室３に臨んで吸気通路１及び
排気通路２の開口に対応し、中間部がガイド５ａ
及び６ａを介してシリンダヘツドｂの壁面に摺動
自在に支持されている。 These exhaust valves 5 and 6 have umbrella portions at their lower ends facing the combustion chamber 3 and correspond to the openings of the intake passage 1 and the exhaust passage 2, respectively, and the middle portion thereof is a guide 5a.
and 6a, and is slidably supported on the wall surface of the cylinder head b.
７，８は前記バルブ５，６の上端に連設された
リフタであり、このリフタ７，８を介して両バル
ブ５，６がその直上に対応するカム軸９，１０に
連繋し、該軸９，１０によつて駆動されるように
なつている。 Reference numerals 7 and 8 indicate lifters connected to the upper ends of the valves 5 and 6, and through these lifters 7 and 8, both valves 5 and 6 are connected to the corresponding camshafts 9 and 10 directly above the lifters 7 and 8. 9 and 10.
１１，１１′及び１２は吸気バルブ５及び排気
バルブ６を閉弁方向に付勢するスプリングであ
る。 Spring 11, 11' and 12 bias the intake valve 5 and exhaust valve 6 in the valve closing direction.
一方、前記カム軸９，１０はシリンダヘツドｂ
の上方においてカムキヤリア１３及びカムキヤツ
プ１４，１５を介して回動自在に保持されてい
る。 On the other hand, the camshafts 9 and 10 are connected to the cylinder head b.
It is rotatably held above the cam carrier 13 and cam caps 14 and 15.
１６は前記カム軸９，１０及びカムキヤツプ１
４，１５を覆うカバーであり、カムキヤリア１３
の上端に連設されている。 16 is the camshaft 9, 10 and the cam cap 1;
It is a cover that covers 4 and 15, and the cam carrier 13
It is connected to the top of the .
そして、この４サイクルエンジンはその出力性
能を向上させるため１気筒当りの吸気バルブ５が
３つと排気バルブ６が２つ設けられ、これら吸排
気バルブ５，６は燃焼室３の中心を通りカム軸
９，１０に平行な中心線１3の一側と他側に振り
分けて配置されている。 In order to improve its output performance, this four-stroke engine is provided with three intake valves 5 and two exhaust valves 6 per cylinder, and these intake and exhaust valves 5 and 6 pass through the center of the combustion chamber 3, They are arranged on one side and the other side of the center line 13 parallel to lines 9 and 10.
また、吸気バルブ５の配置構造は、中間の吸気
バルブが両側の吸気バルブよりもシリンダａの軸
線１1に対する傾きを小さくして燃焼室３に臨ま
されている。 Further, the arrangement structure of the intake valves 5 is such that the middle intake valve faces the combustion chamber 3 with a smaller inclination with respect to the axis 11 of the cylinder a than the intake valves on both sides.
即ち、中間の吸気バルブ５の傾斜角度をα1と
し、両側の吸気バルブ５の傾斜角度をα2とすれば
α1＞α2となる。 That is, if the inclination angle of the middle intake valve 5 is α 1 and the inclination angle of the intake valves 5 on both sides is α 2 , then α 1 >α 2 .
更に、前記吸気バルブ５は夫々その軸線１2が
カム軸９の軸芯０1を通るようになつている。即
ち、カム軸９方向に見て両側の吸気バルブ５と中
間の吸気バルブ５の軸線１2の延長線が吸気バル
ブ５の上方にて交差するようになつている。 Further, each of the intake valves 5 has its axis 1 2 passing through the axis 0 1 of the camshaft 9 . That is, when viewed in the direction of the camshaft 9, extensions of the axes 12 of the intake valves 5 on both sides and the intermediate intake valve 5 intersect above the intake valves 5.
そして、前記吸気バルブ５の各リフタ７は、第
１，４図に示す如く点火プラグを囲むように設け
られたプラグタワー１４の吸気カム軸９側外側面
に位置し、該リフタ７は前記プラグタワー１７の
一部を構成するカムキヤリア１３に一体的に形成
したガイド部１８によつて摺動自在にガイドされ
るようになつている。しかも、両側の吸気バルブ
５を閉方向に付勢するスプリング１１′は第１図
のようにカム軸９方向に見て前記プラグタワー１
７とオーバーラツプするように配設されている。 Each lifter 7 of the intake valve 5 is located on the outer surface of the intake camshaft 9 side of the plug tower 14 provided so as to surround the spark plug, as shown in FIGS. It is configured to be slidably guided by a guide portion 18 that is integrally formed with the cam carrier 13 that constitutes a part of the tower 17. Moreover, the springs 11' that bias the intake valves 5 on both sides in the closing direction are connected to the plug tower 11' when viewed from the direction of the camshaft 9 as shown in FIG.
It is arranged so as to overlap with 7.
このように、吸気バルブ５の各リフタ７はカム
キヤリア１３に一体的に形成したガイド部１８に
よつて正確にガイドされるのでその作動は確実と
なると共に、中間の吸気バルブ５のリフタ７をプ
ラグタワー１７に近付けることができ、また、両
側の吸気バルブ５のスプリング１１′をカム軸方
向に見てプラグタワー１７とオーバーラツプする
ように配設したので、３つの吸気バルブ５の軸線
とシリンダ軸線１1とのなす角度を小さく抑える
ことができ、これによつて各バルブ５をシリンダ
中心に近付けて設置することが可能となつて燃焼
室はコンパクトなものとなる。 In this way, each lifter 7 of the intake valve 5 is accurately guided by the guide portion 18 formed integrally with the cam carrier 13, so that its operation is reliable, and the lifter 7 of the intermediate intake valve 5 can be plugged. The springs 11' of the intake valves 5 on both sides are arranged so as to overlap with the plug tower 17 when viewed in the camshaft direction, so that the axes of the three intake valves 5 and the cylinder axis 1 1 can be kept small, thereby making it possible to install each valve 5 close to the center of the cylinder, resulting in a compact combustion chamber.
更に、第２図に示す如く両側の吸気バルブ５の
傘径ｄを排気バルブ６の傘径Ｄよりも小さくした
ので、両側の吸気バルブ５をカム軸９方向におい
てプラグタワー１７から離して配置することがで
き、スプリング１１′とプラグタワー１７とのオ
ーバーラツプを大きくしながらも大容量の点火プ
ラグを採用することが可能となる。 Furthermore, as shown in FIG. 2, since the diameter d of the intake valves 5 on both sides is made smaller than the diameter D of the exhaust valve 6, the intake valves 5 on both sides are placed away from the plug tower 17 in the direction of the camshaft 9. This makes it possible to use a large-capacity spark plug while increasing the overlap between the spring 11' and the plug tower 17.
また、該第１，４図に示すように吸気バルブ５
の各リフタ７をガイドするガイド部１８を一体的
に形成したカムキヤリア１３を、シリンダヘツド
ｂと別体に構成することによつて、吸気バルブ５
をシリンダヘツドｂに取り付けるにあたつてスプ
リング１１，１１′を圧縮させる作業はカムキヤ
リア１３を取り外して行えばよく、吸気バルブ５
を３つとしたことにより小径となつたリフタ７の
ガイド部１８を取り外して作業ができるのでその
作業性が向上する。しかもカムキヤリア１３には
全吸気バルブ５のリフタ７のガイド部１８が一体
に設けられているので、カムキヤリア１３を取り
外せばバルブスプリング１１，１１′の上方が大
きく開放し、前記作業性が一段と向上する。 In addition, as shown in FIGS. 1 and 4, the intake valve 5
By configuring the cam carrier 13, in which the guide portion 18 for guiding each lifter 7 is formed separately from the cylinder head b, the intake valve 5
The work of compressing the springs 11, 11' when attaching the cam carrier 13 to the cylinder head b can be done by removing the cam carrier 13.
By reducing the number of lifters to three, the guide portion 18 of the lifter 7, which has a small diameter, can be removed to perform the work, thereby improving work efficiency. Moreover, since the guide portion 18 of the lifter 7 of the full intake valve 5 is integrally provided on the cam carrier 13, when the cam carrier 13 is removed, the upper part of the valve springs 11, 11' is largely opened, further improving the workability. .
一方、排気バルブ６は２つ設けられ、燃焼室３
内において前記中心線１3と平行な線１4上に配置
されている。 On the other hand, two exhaust valves 6 are provided, and the combustion chamber 3
It is arranged on a line 14 parallel to the center line 13 within the center.
また、排気バルブ６はその軸線１5が夫々カム
軸１０の軸芯０2を通り、シリンダａの軸線１1に
対する傾斜角度α3が等しく設定されている。 Further, the axes 1 5 of the exhaust valves 6 each pass through the axis 0 2 of the camshaft 10, and the inclination angle α 3 of the cylinder a with respect to the axis 1 1 is set to be equal.
そして、該排気バルブ６は２つであるからそれ
らを燃焼室３内で直列的に配置しても干渉し合う
ことがないと共に、カム軸１０に連繋させる手段
としてリフター８以外のものを新たに必要としな
い。 Since there are two exhaust valves 6, they will not interfere with each other even if they are arranged in series in the combustion chamber 3, and as a means for connecting them to the camshaft 10, a new device other than the lifter 8 is used. do not need.
なお、該実施例において、両側の吸気バルブ５
を開閉するカムのカムノーズ１９を中間の吸気バ
ルブ５を開閉するカムのカムノーズ２０に対して
吸気カム９の軸芯０1を中心として一方向（第１，
４図で時計方向）に多少回転させた位置に配置し
たことによつて、前記３つの吸気バルブ５の開閉
タイミングを合わせることができる。 In this embodiment, the intake valves 5 on both sides
The cam nose 19 of the cam that opens and closes the intermediate intake valve 5 with respect to the cam nose 20 of the cam that opens and closes the intermediate intake valve 5 in one direction (first,
By arranging the intake valves 5 at a position slightly rotated clockwise in FIG. 4, the opening and closing timings of the three intake valves 5 can be synchronized.
［発明の効果］
この発明では、カム軸により駆動される３つの
吸気バルブと２つの排気バルブを各気筒毎に備
え、これら吸排気バルブを燃焼室の中心を通りカ
ム軸に平行な中心線の一側と他側に振り分けて配
置し、プラグタワーに囲まれた点火プラグを燃焼
室の略中央に臨ませ、前記吸気バルブのうち中間
の吸気バルブをその両側の吸気バルブよりもシリ
ンダの軸線に対する傾きを小さくして燃焼室に臨
ませたエンジンであるから、３つの吸気バルブを
互いに干渉することなく配置することができるこ
とは勿論のこと、このようなエンジンにおいて両
側の吸気バルブを閉方向に付勢するスプリングを
カム軸方向に見てプラグタワーとオーバーラツプ
するように配設したので、３つの吸気バルブの軸
線とシリンダ軸線とのなす角度を小さく抑えるこ
とができ、これによつて燃焼室はコンパクトなも
のとなり、圧縮比を高くして総合的に高出力のエ
ンジンが得られる。しかその際、両側の吸気バル
ブの傘径を排気バルブの傘径よりも小さくしたの
で、両側の吸気バルブをカム軸方向においてプラ
グタワーから離して配置することができ、スプリ
ングとプラグタワーとのオーバーラツプを大きく
しながらも高出力エンジンに適した大容量の点火
プラグを配設することができる。[Effect of the invention] In this invention, each cylinder is provided with three intake valves and two exhaust valves driven by a camshaft, and these intake and exhaust valves are arranged along a center line that passes through the center of the combustion chamber and is parallel to the camshaft. The spark plugs surrounded by the plug towers are arranged on one side and the other side, and the spark plugs surrounded by the plug towers face approximately the center of the combustion chamber. Since the engine has a small inclination that faces the combustion chamber, it goes without saying that the three intake valves can be arranged without interfering with each other. The springs that actuate are arranged so that they overlap with the plug tower when viewed in the direction of the camshaft, so the angle between the axes of the three intake valves and the cylinder axis can be kept small, resulting in a compact combustion chamber. This increases the compression ratio and provides an engine with overall high output. However, since the diameter of the intake valves on both sides was made smaller than the diameter of the exhaust valve, it was possible to locate the intake valves on both sides away from the plug tower in the camshaft direction, thereby reducing the overlap between the spring and the plug tower. It is possible to install a large-capacity spark plug suitable for a high-output engine while increasing the size of the engine.
第１図はこの発明に係るエンジンの実施例の縦
断面図、第２図は第１図の−線断面図、第３
図は第１図の−線断面図、第４図は第２図の
−線断面図を示す。
ａ……シリンダ、ｄ……両側の吸気バルブの傘
径、Ｄ……排気バルブの傘径、３……燃焼室、５
……吸気バルブ、６……排気バルブ、９，１０…
…カム軸、１１，１１′……スプリング、１７…
…プラグタワー、１1……シリンダの軸線、１2…
…吸気バルブの軸線、１3……燃焼室の中心を通
りカム軸に平行な中心線、α1……中間の吸気バル
ブの傾斜角度、α2……両側の吸気バルブの傾斜角
度。
FIG. 1 is a longitudinal cross-sectional view of an embodiment of the engine according to the present invention, FIG. 2 is a cross-sectional view taken along the - line in FIG.
The figure shows a cross-sectional view taken along the line -- in FIG. 1, and FIG. 4 shows a cross-sectional view taken along the line -- in FIG. a... Cylinder, d... Cap diameter of both intake valves, D... Cap diameter of exhaust valve, 3... Combustion chamber, 5
...Intake valve, 6...Exhaust valve, 9,10...
...Camshaft, 11, 11'...Spring, 17...
...Plug tower, 1 1 ...Cylinder axis, 1 2 ...
...Axis of the intake valve, 1 3 ...Center line passing through the center of the combustion chamber and parallel to the camshaft, α 1 ...Inclination angle of the middle intake valve, α 2 ...Inclination angle of the intake valves on both sides.
Claims (1)
２つの排気バルブを各気筒毎に備え、これら吸排
気バルブを燃焼室の中心を通りカム軸に平行な中
心線の一側と他側に振り分けて配置し、プラグタ
ワーに囲まれた点火プラグを燃焼室の略中央に臨
ませた４サイクルエンジンにおいて、前記吸気バ
ルブのうち中間の吸気バルブを前記中心線に対し
てプラグタワーの外側に、両側の吸気バルブをプ
ラグタワーのカム軸方向両側に位置させ、両側の
吸気バルブのシリンダ軸線に対する傾きが中間の
吸気バルブのそれよりも大きく、かつカム軸方向
に見て両側の吸気バルブと中間の吸気バルブの軸
線の延長線が吸気バルブの上方にて交差するよう
に両側の吸気バルブを傾斜させ、両側の吸気バル
ブの傘径を排気バルブの傘径よりも小さくすると
共に、両側の吸気バルブを閉方向に付勢するスプ
リングをカム軸方向に見てプラグタワーとオーバ
ーラツプするように配設したことを特徴とする４
サイクルエンジン。1 Each cylinder has three intake valves and two exhaust valves driven by a camshaft, and these intake and exhaust valves are distributed to one side and the other side of a center line that passes through the center of the combustion chamber and is parallel to the camshaft. In a four-cycle engine in which a spark plug surrounded by a plug tower faces approximately the center of the combustion chamber, the middle intake valve of the intake valves is placed outside the plug tower with respect to the center line, and the spark plugs are placed on both sides of the combustion chamber. The intake valves are located on both sides of the plug tower in the camshaft direction, and the inclination of the intake valves on both sides with respect to the cylinder axis is larger than that of the middle intake valve, and the intake valves on both sides and the middle intake valve are arranged so that the inclination of the intake valves on both sides with respect to the cylinder axis is larger than that of the middle intake valve. The intake valves on both sides are tilted so that the extended lines of the axes intersect above the intake valves, the diameters of the intake valves on both sides are made smaller than the diameter of the exhaust valve, and the intake valves on both sides are tilted in the closing direction. 4. The spring biasing the plug tower is arranged so as to overlap the plug tower when viewed in the direction of the camshaft.
cycle engine.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2969689A JPH01257707A (en) | 1989-02-10 | 1989-02-10 | Four-cycle engine |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2969689A JPH01257707A (en) | 1989-02-10 | 1989-02-10 | Four-cycle engine |
Related Parent Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP6184381A Division JPS57176311A (en) | 1981-04-22 | 1981-04-22 | Four-cycle engine |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH01257707A JPH01257707A (en) | 1989-10-13 |
| JPH0320568B2 true JPH0320568B2 (en) | 1991-03-19 |
Family
ID=12283273
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP2969689A Granted JPH01257707A (en) | 1989-02-10 | 1989-02-10 | Four-cycle engine |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH01257707A (en) |
-
1989
- 1989-02-10 JP JP2969689A patent/JPH01257707A/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| JPH01257707A (en) | 1989-10-13 |
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