JP2716802B2 - V-type two-cycle two-cylinder engine for motorcycles - Google Patents
V-type two-cycle two-cylinder engine for motorcyclesInfo
- Publication number
- JP2716802B2 JP2716802B2 JP1162092A JP16209289A JP2716802B2 JP 2716802 B2 JP2716802 B2 JP 2716802B2 JP 1162092 A JP1162092 A JP 1162092A JP 16209289 A JP16209289 A JP 16209289A JP 2716802 B2 JP2716802 B2 JP 2716802B2
- Authority
- JP
- Japan
- Prior art keywords
- cylinder
- engine
- type
- intake
- vehicle
- 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
- F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
- F02M35/00—Combustion-air cleaners, air intakes, intake silencers, or induction systems specially adapted for, or arranged on, internal-combustion engines
- F02M35/10—Air intakes; Induction systems
- F02M35/1015—Air intakes; Induction systems characterised by the engine type
- F02M35/1019—Two-stroke engines; Reverse-flow scavenged or cross scavenged engines
-
- 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
- F02B75/16—Engines characterised by number of cylinders, e.g. single-cylinder engines
- F02B75/18—Multi-cylinder engines
- F02B75/22—Multi-cylinder engines with cylinders in V, fan, or star arrangement
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
- F02M35/00—Combustion-air cleaners, air intakes, intake silencers, or induction systems specially adapted for, or arranged on, internal-combustion engines
- F02M35/10—Air intakes; Induction systems
- F02M35/10242—Devices or means connected to or integrated into air intakes; Air intakes combined with other engine or vehicle parts
- F02M35/10275—Means to avoid a change in direction of incoming fluid, e.g. all intake ducts diverging from plenum chamber at acute angles; Check valves; Flame arrestors for backfire prevention
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
- F02M35/00—Combustion-air cleaners, air intakes, intake silencers, or induction systems specially adapted for, or arranged on, internal-combustion engines
- F02M35/10—Air intakes; Induction systems
- F02M35/104—Intake manifolds
- F02M35/116—Intake manifolds for engines with cylinders in V-arrangement or arranged oppositely relative to the main shaft
-
- 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
- F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
- F02M35/00—Combustion-air cleaners, air intakes, intake silencers, or induction systems specially adapted for, or arranged on, internal-combustion engines
- F02M35/16—Combustion-air cleaners, air intakes, intake silencers, or induction systems specially adapted for, or arranged on, internal-combustion engines characterised by use in vehicles
- F02M35/162—Motorcycles; All-terrain vehicles, e.g. quads, snowmobiles; Small vehicles, e.g. forklifts
Landscapes
- Engineering & Computer Science (AREA)
- Chemical & Material Sciences (AREA)
- Combustion & Propulsion (AREA)
- Mechanical Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Cylinder Crankcases Of Internal Combustion Engines (AREA)
Description
【発明の詳細な説明】 〔産業上の利用分野〕 本発明は、例えば自動二輪車に好適のＶ型２サイクル
２気筒エンジンの吸気装置に関し、特に気筒間ピッチを
狭くしながらリードバルブ面積を充分に確保できるよう
にしたリードバルブ取付用吸気口の形状の改善に関す
る。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an intake device for a V-type two-stroke two-cylinder engine suitable for, for example, a motorcycle, and more particularly, to a sufficient reed valve area while reducing a pitch between cylinders. The present invention relates to an improvement in a shape of a reed valve mounting intake port that can be secured.
２サイクル２気筒エンジンにおいてエンジンの一次振
動の原因になる左，右気筒間の偶力を軽減させるために
は、気筒間ピッチを小さくする必要がある。この気筒間
ピッチは、一般には、クランク軸の中央を支持するセ
ンタベアリング及び左，右気筒間をシールするオイルシ
ールの幅、左，右気筒の内側クランクウェブの厚さ、
コンロッド大端部の幅の和によって決定される。従っ
て従来の２サイクル２気筒エンジンでは、気筒間ピッチ
を狭小化するために上記〜の幅を狭くするための工
夫がなされている。In a two-cycle two-cylinder engine, in order to reduce the couple between the left and right cylinders that causes primary vibration of the engine, it is necessary to reduce the pitch between the cylinders. The pitch between the cylinders is generally the width of a center bearing that supports the center of the crankshaft and the width of an oil seal that seals between the left and right cylinders, the thickness of the inner crank webs of the left and right cylinders,
It is determined by the sum of the widths of the large ends of the connecting rods. Therefore, in the conventional two-stroke two-cylinder engine, a contrivance has been made to reduce the above widths in order to narrow the inter-cylinder pitch.
ところでクランクケースに、クランク室と直接連通す
る吸気口を形成し、該吸気口内にリードバルブを配設し
たクランクケースリードバルブ方式のエンジンの場合、
性能向上を図るには上記リードバルブの面積を充分に確
保するために、吸気口の開口面積をできるだけ大きくす
る必要がある。ところがＶ型２サイクル２気筒エンジン
の場合は、左，右の気筒間ピッチをそのままにして吸気
口面積を拡大すると左，右の吸気口同士が干渉すること
となり、これを避けるために気筒間ピッチを拡げざるを
得ない。従って結局、Ｖ型２サイクル２気筒エンジンの
場合は、上記〜よりもむしろ吸気口形状によって気
筒間ピッチの狭小化に限界が生じている。By the way, in the case of a crankcase reed valve type engine in which an intake port directly communicating with a crank chamber is formed in a crankcase and a reed valve is disposed in the intake port,
In order to improve the performance, it is necessary to increase the opening area of the intake port as much as possible in order to secure a sufficient area of the reed valve. However, in the case of a V-type two-cycle two-cylinder engine, if the intake port area is enlarged while keeping the left and right cylinder pitches as they are, the left and right intake ports interfere with each other. I have to expand. Therefore, in the case of the V-type two-cycle two-cylinder engine, the narrowing of the inter-cylinder pitch is limited by the shape of the intake port rather than the above.
本発明は、上記従来の問題点に鑑みてなされたもの
で、気筒間ピッチを狭くしながら所要の吸気口面積、ひ
いてはリードバルブ面積を確保できる自動二輪車用Ｖ型
２サイクル２気筒エンジンの吸気装置を提供することを
目的としている。SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned conventional problems, and is an intake apparatus for a V-type two-stroke two-cylinder engine for a motorcycle, which can secure a required intake port area and a reed valve area while reducing a pitch between cylinders. It is intended to provide.
本発明は、左，右一対の気筒を所定角度のバンクをな
すよう配置してなり、該バンクが車両前方を向くように
車体フレームに搭載された自動二輪車用Ｖ型２サイクル
２気筒エンジンに混合気を供給する吸気装置において、
クランクケースの上記バンク内部分に左，右のクランク
室に連通する左，右一対の吸気口を車幅方向に隣接する
ように形成し、該各吸気口のクランク室内側にリードバ
ルブを、クランク室外側に気化器をそれぞれ配設し、上
記各吸気口の幅方向中心を左，右の気筒の中心線より外
側に偏位させるとともに、上記各気化器を車両前側の間
隔が広くなるよう斜め外側に向けて配置したことを特徴
としている。According to the present invention, a pair of left and right cylinders are arranged so as to form a bank having a predetermined angle, and the bank is mixed with a V-type two-cycle two-cylinder engine for a motorcycle mounted on a body frame such that the bank faces forward of the vehicle. In the intake device that supplies air,
A pair of left and right intake ports communicating with the left and right crank chambers are formed adjacent to each other in the width direction of the vehicle in a portion of the bank inside the bank of the crankcase. A carburetor is disposed on the outside of the vehicle, and the center in the width direction of each of the intake ports is deviated outside the center line of the left and right cylinders. It is characterized by being arranged outward.
ここで本発明において気化器とは、フロート室内のガ
ソリンをベンチュリ負圧で吸引して霧化する通常の気化
器だけでなく、ベンチュリ管内に燃料噴射弁及び絞り弁
を配設してなる燃料噴射装置も含む概念である。Here, in the present invention, the carburetor is not only a normal carburetor that sucks and atomizes gasoline in a float chamber with a Venturi negative pressure, but also a fuel injection valve in which a fuel injection valve and a throttle valve are arranged in a Venturi pipe. This is a concept that also includes devices.
本発明に係る自動二輪車用Ｖ型２サイクル２気筒エン
ジンの吸気装置によれば、吸気口の中心を気筒中心より
車幅方向外側に偏位させたので、この吸気口の幅寸法が
気筒間ピッチを規制することはなく、逆に吸気口面積が
気筒間ピッチに規制されることもない。従って上述の
〜の幅寸法を狭くすることによって気筒間ピッチを狭
小化でき、かつ上記偏位量を適宜設定することによって
充分な吸気口面積、ひいてはリードバルブ面積を確保で
きる、 また、左，右の気化器を車両前側の間隔が広くなるよ
うに斜め外方に向けて配置したので、走行風を気化器に
導入する際に前輪が邪魔になることがなく、この点から
もエンジン性能を向上でき、さらにまた左，右の気化器
を外側に向けて配置したので、該各気化器が相手側シリ
ンダ，及びシリンダヘッド等と干渉するのを回避でき
る。According to the intake device for a V-type two-stroke two-cylinder engine for a motorcycle according to the present invention, the center of the intake port is displaced outward from the center of the cylinder in the vehicle width direction. Is not regulated, and conversely, the intake port area is not regulated by the inter-cylinder pitch. Therefore, the inter-cylinder pitch can be narrowed by narrowing the width dimension of the above-mentioned (1), and a sufficient intake port area and, consequently, a reed valve area can be ensured by appropriately setting the deviation amount. The carburetor is positioned obliquely outward so as to increase the distance between the front side of the vehicle, so that the front wheels do not hinder the introduction of traveling wind to the carburetor, and this also improves engine performance In addition, since the left and right carburetors are arranged facing outward, it is possible to prevent the respective carburetors from interfering with the mating cylinder, the cylinder head, and the like.
以下、本発明の実施例を図について説明する。 Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
第１図ないし第10図は本発明の一実施例による自動二
輪車用Ｖ型２サイクル２気筒エンジンを説明するための
図である。1 to 10 are views for explaining a V-type two-stroke two-cylinder engine for a motorcycle according to one embodiment of the present invention.
図において、１は本実施例エンジンが搭載された自動
二輪車であり、これの車体フレーム２はヘッドパイプ2a
に左，右一対の横断面長方形の筒状のメインフレーム2b
の前端を溶接接続し、該各メインフレーム2bの後端に溶
接接続されたリヤアームブラケット2c同士をクロスパイ
プ（図示せず）で接続した構成となっている。上記ヘッ
ドパイプ2aによって、下端で前輪３を軸支する前フォー
ク４が左右に操向自在に軸支されており、上記リヤアー
ムブラケット2cによって、後端で後輪５を軸支するリヤ
アーム６が上下に揺動自在に軸支されている。なお、７
は燃料タンク等を覆うタンクカバー、８はシートであ
る。In the figure, reference numeral 1 denotes a motorcycle on which the engine of this embodiment is mounted, and a body frame 2 of the motorcycle 1 has a head pipe 2a.
The left and right pair of rectangular main frame 2b with a rectangular cross section
Are connected by welding, and the rear arm brackets 2c, which are connected by welding to the rear end of each main frame 2b, are connected by a cross pipe (not shown). A front fork 4 that supports the front wheel 3 at the lower end is supported by the head pipe 2a so as to be steerable left and right. A rear arm 6 that supports the rear wheel 5 at the rear end is vertically moved by the rear arm bracket 2c. It is pivotally supported by the shaft. Note that 7
Is a tank cover for covering the fuel tank and the like, and 8 is a seat.
上記左，右のメインフレーム2bの左，右下方部分及び
ヘッドパイプ2aの前方部分は、カウリング９で囲まれて
おり、該カウリング９内に水冷式Ｖ型２サイクル２気筒
のエンジンユニット10が懸架支持されている。このエン
ジンユニット10は、前，後２分割式クランクケース11の
前部に形成された接続開口11cに、上側シリンダ12a,上
側ヘッド12bを斜め上方に向けて積層し、ヘッドボルト1
4で結合するとともに、接続開口11dに下側シリンダ13a,
下側ヘッド13bを上記上側シリンダ12aと90度をなすよう
斜め下方に向けて積層し、ヘッドボルト14で結合した構
成となっている。なお、車両前方から見て（以下全て同
じ）左側に上側シリンダ12aが、右側に下側シリンダ13b
が位置している。The left and right lower parts of the left and right main frames 2b and the front part of the head pipe 2a are surrounded by a cowling 9, in which a water-cooled V-type two-stroke two-cylinder engine unit 10 is suspended. Supported. The engine unit 10 has an upper cylinder 12a and an upper head 12b stacked diagonally upward on a connection opening 11c formed at the front of a front and rear split crankcase 11, and a head bolt 1
4, and the lower cylinder 13a,
The lower head 13b and the upper cylinder 12a are stacked obliquely downward so as to form 90 degrees with each other, and are connected by head bolts 14. When viewed from the front of the vehicle (the same applies hereinafter), the upper cylinder 12a is on the left and the lower cylinder 13b is on the right.
Is located.
上記クランクケース11の前，後分割面（ケース合面）
にクランク軸15が配設されている。このクランク軸15
は、第１〜第３クランク16〜18からなる３分割式のもの
で、第1,第３クランク16,18は主軸部16a,18aの内方端に
外側ウェブ16b,18bを一体形成してなり、第２クランク1
7は主軸部17aの両端に内側ウェブ17bを一体形成してな
る。またこの内側ウェブ17bのコンロッド接続側と反対
側には重錘17dが圧入固定されており、これは該クラン
ク軸15のアンバランス量を確保して一次振動を軽減する
ためのものである。そしてこの第１〜第３クランク16〜
18は、第２クランク17の内側ウェブ17bの反重錘側に一
体形成されたクランクピン17cを上記外側ウェブ16b,18b
に圧入することによって組み立てられている。上記左，
右の内側，外側ウェブ17b,16b及び17b,18bは、それぞれ
クランクケース11内に形成された左，右のクランク室11
a,11b内に収容配置されている。また上記第1,第３クラ
ンク16,18は端部転がり軸受19a,19bで軸支され、第２ク
ランク17は中央転がり軸受19cで軸支されている。Front and rear split surfaces of the above crankcase 11 (case mating surface)
The crankshaft 15 is disposed at the center. This crankshaft 15
Is a three-split type comprising first to third cranks 16 to 18. The first and third cranks 16, 18 are formed by integrally forming outer webs 16b, 18b at the inner ends of the main shaft portions 16a, 18a. And the second crank 1
7 is formed by integrally forming inner webs 17b at both ends of a main shaft portion 17a. In addition, a weight 17d is press-fitted and fixed to the inner web 17b on the side opposite to the connecting rod connection side, in order to secure an imbalance amount of the crankshaft 15 and reduce primary vibration. And these first to third cranks 16 ~
The crank pin 17c formed integrally with the inner web 17b of the second crank 17 on the opposite side of the weight is connected to the outer webs 16b and 18b.
It is assembled by press-fitting. Above left,
The right inner and outer webs 17b, 16b and 17b, 18b are respectively formed in the left and right crank chambers 11 formed in the crankcase 11.
a, 11b. The first and third cranks 16 and 18 are supported by end rolling bearings 19a and 19b, and the second crank 17 is supported by a central rolling bearing 19c.
そして上記第２クランク17の主軸部17aには、両クラ
ンク室11a,11b間をシールするためのシールラビリンス2
0が中央軸受19cに隣接するよう配設されている。このシ
ールラビリンス20は、リング状のバックアップ部材20a
の内面にシール部材20bを固着してなる二分割構造のも
のであり、ノックピン20fで位置決めするとともに、ボ
ルト20eで固定するようになっている。上記シール部材2
0bの内面及び側面にはシールリップ20c,20dが形成され
ており、シールリップ20cは主軸部17aに摺接し、シール
リップ20dは内側ウェブ17bに摺接している。The main shaft portion 17a of the second crank 17 has a seal labyrinth 2 for sealing between the two crank chambers 11a and 11b.
0 is disposed adjacent to the central bearing 19c. The seal labyrinth 20 has a ring-shaped backup member 20a.
It has a two-part structure in which a seal member 20b is fixed to the inner surface of the device, and is positioned by a knock pin 20f and fixed by a bolt 20e. The above sealing member 2
Seal lips 20c and 20d are formed on the inner surface and side surfaces of 0b, and the seal lip 20c is in sliding contact with the main shaft portion 17a, and the seal lip 20d is in sliding contact with the inner web 17b.
また上記各クランクピン17cにはニードル軸受23を介
してコンロッド24の大端部が連結されており、該コンロ
ッド24の小端部にはピストンピン25aを介してピストン2
5が接続されている。なお、21はバランサ軸であり、こ
れは上記クランク軸15に伝動ギヤ22a,22bを介して連結
されている。A large end of a connecting rod 24 is connected to each of the crank pins 17c via a needle bearing 23, and a small end of the connecting rod 24 is connected to a piston 2 via a piston pin 25a.
5 is connected. Reference numeral 21 denotes a balancer shaft, which is connected to the crankshaft 15 via transmission gears 22a and 22b.
そして上記クランクケース11の、上記上側，下側シリ
ンダ12a,13a間部分には、上記左，右のクランク室11a,1
1bに直接連通する左，右一対の吸気口26,27が形成され
ている。この吸気口26,27は横長の長方形状をなしてお
り、正面から見ると、そのエンジン幅方向の中心線M1,M
2は各気筒中心線L1,L2より、幅方向外側にＤだけ偏位し
ている。なお、この偏位量Ｄは、必要な吸気口面積と、
主としてバンク角によって決定される吸気口高さとから
適宜設定される。また吸気口26,27は側面から見ると、
該各吸気口26,27の取付座（外端面）26a,27aは、上記上
側，下側の気筒中心線L1,L2の２等分線Ａよりそれぞれ
θ１だけ下方，上方を向いている。The upper and lower cylinders 12a, 13a of the crankcase 11 are provided between the left and right crank chambers 11a, 1a.
A pair of left and right intake ports 26 and 27 that directly communicate with 1b are formed. The intake ports 26 and 27 have a horizontally-long rectangular shape, and when viewed from the front, center lines M1 and M in the engine width direction are provided.
Reference numeral 2 deviates from the cylinder center lines L1 and L2 by D outward in the width direction. Note that this deviation amount D is determined by the required intake port area and
It is set as appropriate mainly from the intake port height determined mainly by the bank angle. Also, when the inlets 26 and 27 are viewed from the side,
The mounting seats (outer end surfaces) 26a, 27a of the intake ports 26, 27 are respectively directed downward and upward by θ1 from the bisector A of the upper and lower cylinder center lines L1, L2.
上記左，右の吸気口26,27の内方には、同一形状の
左，右のリードバルブ28,28が上，下逆向きに配設され
ている。このリードバルブ28,28は、側面から見ると、
その中心線ｌが、上記取付座26a,又は27aと直角な直線
ｌ′（２分割線Ａとの交差角θ１の直線）よりさらに上
方，下方を向くように、つまりバルブ中心線ｌと気筒中
心線L1,L2とのなす角度θ２がより鋭角に近くなるよう
に取り付けられている。このリードバルブ28は、横断面
三角形筒状（第４図参照）の本体28aの二側壁に吐出口2
8bを、一側壁に吸入口28dを形成してなり、該吐出口28b
は、薄板状の弁板28cで開閉可能となっている。なお、2
8eは弁板28cのストッパである。Inside the left and right intake ports 26, 27, left and right reed valves 28, 28 of the same shape are arranged in the opposite directions, ie, upside down. When viewed from the side, the reed valves 28, 28
The center line l is directed further upward and downward from a straight line l '(a straight line having an intersection angle θ1 with the dividing line A) perpendicular to the mounting seat 26a or 27a, that is, the valve center line l and the cylinder center. It is attached so that the angle θ2 between the lines L1 and L2 is closer to an acute angle. The reed valve 28 has a discharge port 2 on two side walls of a main body 28a having a triangular cross section (see FIG. 4).
8b, a suction port 28d is formed on one side wall, and the discharge port 28b
Can be opened and closed by a thin valve plate 28c. Note that 2
8e is a stopper for the valve plate 28c.
上記各吸気口26,27の外側には、同一形状のキャブジ
ョイント30,30を介して同じく同一形状の気化器31,31が
接続されている。上記各キャブジョイント30も上，下逆
に取り付けられており、その中心線は、側面から見る
と、上記直線ｌ′方向に延びた後、上記２等分線Ａと平
行に延びており、平面から見ると車幅方向外側に湾曲し
ている。またこのキャブジョイント30の下流端にはガイ
ド部30cが形成されており、該ガイド部30cはリードバル
ブ28の左，右側壁に沿って内方に延び（第７図参照）、
かつ上，下の吐出口28bに混合気を案内するためにその
縁部が薄肉になるよう曲面状に形成されている（第８図
参照）。Outside the intake ports 26 and 27, carburetors 31 and 31 having the same shape are connected via cab joints 30 and 30 having the same shape. Each of the cab joints 30 is also mounted upside down, and its center line extends in the direction of the straight line l 'when viewed from the side, and then extends in parallel with the bisector A. It is curved outward in the vehicle width direction when viewed from above. A guide portion 30c is formed at the downstream end of the cab joint 30, and the guide portion 30c extends inward along the left and right side walls of the reed valve 28 (see FIG. 7).
In order to guide the air-fuel mixture to the upper and lower discharge ports 28b, the air-fuel mixture is formed into a curved surface so that its edge is thin (see FIG. 8).
そして上記キャブジョイント30の上流端の接続口30e
に上記各気化器31が接続されているのであるが、上述の
ように各キャブジョイント30が上，下逆に接続されてい
ることから、上側シリンダ12a用気化器31は上記２等分
線Ａに対してH1だけ下方に、下側シリンダ13a用気化器3
1は２等分線Ａに対してH2だけ上方に偏位している。ま
た、平面から見ると各気化器31は左，右外方に向いてお
り、該各気化器31の近傍には上記カウリング９に一体形
成された導入ダクト9bの吐出口9cが位置している。この
導入ダクト9bの吸込口9aはカウリング９の前端の左，右
コーナ部に開口している。And the connection port 30e at the upstream end of the cab joint 30
The carburetors 31 are connected to the upper cylinder 12a. Since the carb joints 30 are connected upside down as described above, the carburetor 31 for the upper cylinder 12a is connected to the bisector A , The carburetor 3 for the lower cylinder 13a
1 is shifted upward by H2 with respect to the bisector A. When viewed from a plane, each carburetor 31 faces left and right outwards, and a discharge port 9c of an introduction duct 9b integrally formed with the cowling 9 is located near each carburetor 31. . The inlet 9a of the introduction duct 9b is open at the left and right corners of the front end of the cowling 9.
次に本実施例の作用効果について説明する。 Next, the operation and effect of this embodiment will be described.
本実施例では、走行風がカウリング９の導入ダクト9b
を介して各気化器31の周囲に導入される。またエンジン
ユニット10では、ピストン25の上昇に伴ってクランク室
11a,11b内が負圧になると、各リードバルブ28の弁板28c
が吐出口28bを開き、気化器31からの混合気がこのリー
ドバルブ28を介してクランク室11a,11b内に吸入され
る。この場合に、エンジン性能を向上させるには、リー
ドバルブ面積を拡大する必要があるが、Ｖ型２サイクル
２気筒エンジンにおいて、左，右の気筒の軸線と、吸気
口の軸線とが一致した構造の場合、吸気口面積の拡大に
伴って気筒間ピッチも大きくなる。これに対して本実施
例では、左，右の上側，下側シリンダ12a,13aの軸線L1,
L2に対して、吸気口26,27の中心線M1,M2を幅方向外側に
Ｄだけ偏位させたので、気筒間ピッチを拡げることなく
必要な吸気口面積、ひいてはリードバルブ面積を確保で
き、エンジン性能を向上できる。In the present embodiment, the traveling wind is the introduction duct 9 b of the cowling 9.
And is introduced around each vaporizer 31 through. In the engine unit 10, the crank chamber
When the inside of 11a, 11b becomes negative pressure, the valve plate 28c of each reed valve 28
Opens the discharge port 28b, and the air-fuel mixture from the vaporizer 31 is sucked into the crank chambers 11a and 11b via the reed valve 28. In this case, in order to improve the engine performance, it is necessary to enlarge the reed valve area. However, in a V-type two-stroke two-cylinder engine, a structure in which the axes of the left and right cylinders coincide with the axis of the intake port In the case of, the inter-cylinder pitch increases with an increase in the intake port area. On the other hand, in the present embodiment, the left and right upper and lower cylinders 12a, 13a have axes L1,
With respect to L2, the center lines M1 and M2 of the intake ports 26 and 27 are deviated by D outward in the width direction, so that the necessary intake port area and, consequently, the reed valve area can be secured without increasing the cylinder pitch. Engine performance can be improved.
ここで本実施例では、吸気口の幅によって気筒間ピッ
チが制約を受けることがないから、上述の〜に示し
た幅寸法の内、例えば内側ウェブの幅を狭くすることに
よって気筒間ピッチをより狭小化できる。即ち、本実施
例では、クランク軸15を第１〜第３クランク16〜18から
なる３分割構造にするとともに、第２クランク17の両内
側ウェブ17bに一体形成したクランクピン17c,17cを外側
ウェブ16b,18bに圧入する構造としたので、この内側ウ
ェブ17bの厚さを薄くでき、それだけ気筒間ピッチを狭
くできる。ちなみに従来のクランク軸では、例えば第２
クランク17の主軸部17aを内側ウェブ17bに圧入する構造
のものが一般的であったが、この場合は結合剛性を確保
するために、内側ウェブ17bを厚くする必要があり、そ
れだけ気筒間ピッチが大きくなる問題があった。Here, in the present embodiment, the inter-cylinder pitch is not restricted by the width of the intake port. Can be narrowed. That is, in the present embodiment, the crankshaft 15 has a three-part structure including the first to third cranks 16 to 18 and the crank pins 17c, 17c integrally formed on both inner webs 17b of the second crank 17 are connected to the outer webs. Since the structure is such that the inner web 17b is press-fitted into the 16b and 18b, the thickness of the inner web 17b can be reduced, and the pitch between cylinders can be narrowed accordingly. By the way, in the conventional crankshaft, for example, the second
In general, the main shaft portion 17a of the crank 17 is press-fitted into the inner web 17b, but in this case, the inner web 17b needs to be thickened in order to secure the coupling rigidity, and the inter-cylinder pitch is accordingly reduced. There was a growing problem.
また本実施例では、上側シリンダ12a用気化器31につ
いては下側にH1だけ偏位させるとともに、下側シリンダ
13a用気化器31については上側にH2だけ偏位させたの
で、気化器とシリンダとが干渉しにくくなり、それだけ
各気化器をクランク軸15側に、つまり車両後方に寄せて
接続でき、エンジンユニットの前後長を全体として短縮
できる。これによりエンジンユニットの搭載位置上の自
由度を拡大でき、軸間距離（ホイルベース）を従来のま
まにしてエンジンユニットを車両前側に寄せて搭載すれ
ば、前輪荷重を増加させて操縦安定性を向上できる。勿
論、軸間距離を短縮して車両全体を小型化することもで
きる。In this embodiment, the carburetor 31 for the upper cylinder 12a is displaced downward by H1 and the lower cylinder
Since the carburetor 31 for 13a is displaced upward by H2, the carburetor and the cylinder are less likely to interfere with each other, so that each carburetor can be connected to the crankshaft 15 side, that is, closer to the rear of the vehicle, and connected to the engine unit. Can be shortened as a whole. As a result, the degree of freedom in the mounting position of the engine unit can be expanded, and if the engine unit is mounted closer to the front side of the vehicle while keeping the center distance (wheel base) as it is, the front wheel load is increased and steering stability is improved. it can. Of course, it is also possible to reduce the distance between the shafts to reduce the size of the entire vehicle.
また、本実施例では、同一形状のリードバルブ28,キ
ャブジョイント30を、上記２等分線Ａに対して対称にな
るよう上，下逆に接続したので、各部品の共用化を実現
でき、しかもリードバルブ28については気筒中心線L1,L
2となす角θ２をより鈍角に近くして混合気の吸入をよ
り円滑化できる。Further, in the present embodiment, the reed valve 28 and the cab joint 30 having the same shape are connected upside down and upside down so as to be symmetrical with respect to the bisector A, so that each part can be shared. Moreover, for the reed valve 28, the cylinder center lines L1, L
By setting the angle θ2 to 2 closer to an obtuse angle, the intake of the air-fuel mixture can be more smoothly performed.
さらにまた、左，右の気化器31,31を車両前側の間隔
が広くなるように斜め外方に向けて配置したので、走行
風を気化器に導入する際に前輪３が邪魔になることがな
く、この点からもエンジン性能を向上でき、また該各気
化器31,31が相手側シリンダ，及びシリンダヘッド等と
干渉するのを防止できる。Furthermore, since the left and right carburetors 31 and 31 are arranged obliquely outward so as to increase the distance between the front side of the vehicle, the front wheels 3 may become obstructive when the traveling wind is introduced into the carburetor. In addition, the engine performance can be improved from this point, and the carburetors 31, 31 can be prevented from interfering with the mating cylinder, the cylinder head, and the like.
以上のように本発明に係る自動二輪車用Ｖ型２サイク
ル２気筒エンジンの吸気装置によれば、リードバルブを
装着する吸気口を、気筒中心線に対して車幅方向外側に
偏位させたので、気筒間ピッチを狭小化しながら吸気口
面積，ひいてはリードバルブ面積を充分に確保でき、エ
ンジン性能を向上できる効果があり、また左，右の気化
器を車両前側の間隔が広くなるように斜め外方に向けて
配置したので、走行風を気化器に導入する際に前輪が邪
魔になることがなく、この点からもエンジン性能を向上
でき、さらにまた左，右の気化器を外側に向けて配置し
たので、該各気化器が相手側シリンダ，及びシリンダヘ
ッド等と干渉するのを回避できる効果がある。As described above, according to the intake device for a V-type two-stroke two-cylinder engine for a motorcycle according to the present invention, the intake port for mounting the reed valve is deviated outward in the vehicle width direction with respect to the cylinder center line. In addition, it is possible to secure the intake port area and, consequently, the reed valve area while narrowing the inter-cylinder pitch, thereby improving the engine performance. The front wheels are not obstructed when the wind is introduced into the carburetor, so the engine performance can be improved from this point, and the left and right carburetors face outward. Since they are arranged, there is an effect that each carburetor can be prevented from interfering with the other cylinder, the cylinder head, and the like.
第１図ないし第10図は本発明の一実施例によるＶ型２サ
イクル２気筒エンジンの吸気装置を説明するための図で
あり、第１図はその気筒中心線と吸気口中心との関係を
示す正面図、第２図はエンジン全体の正面図、第３図は
該エンジンの内部構造を示す断面正面図、第４図はその
一部断面側面図、第５図は該エンジンの配置状態を示す
平面図、第６図シリンダボディ，吸気口の平面図、第７
図はリードバルブ部分の断面平面図、第８図は第７図の
VIII−VIII線断面図、第９図はシールラビリンスの断面
図、第10図は本実施例エンジンを搭載した自動二輪車の
左側面図である。 図において、２は車体フレーム、10はＶ型２サイクル２
気筒エンジン、11はクランクケース、12a,13aは上側，
下側シリンダ（左，右の気筒）、26,27は左，右の吸気
口、28はリードバルブ、31は気化器、Ｄは偏位量、L1,L
2は気筒中心線、M1,M2は吸気口の中心線である。1 to 10 are views for explaining an intake device of a V-type two-stroke two-cylinder engine according to one embodiment of the present invention. FIG. 1 shows the relationship between the cylinder center line and the center of the intake port. FIG. 2 is a front view of the entire engine, FIG. 3 is a cross-sectional front view showing the internal structure of the engine, FIG. 4 is a partial cross-sectional side view thereof, and FIG. FIG. 6 is a plan view showing the cylinder body and the intake port, FIG.
The figure is a cross-sectional plan view of the reed valve part, and FIG.
FIG. 9 is a sectional view of the seal labyrinth, and FIG. 10 is a left side view of the motorcycle equipped with the engine of this embodiment. In the figure, 2 is a body frame, 10 is a V-type 2 cycle 2
Cylinder engine, 11 is the crankcase, 12a and 13a are the upper side,
Lower cylinders (left and right cylinders), 26 and 27 are left and right intakes, 28 is a reed valve, 31 is a carburetor, D is displacement, L1, L
2 is the cylinder center line, and M1 and M2 are the center lines of the intake port.
Claims (1)
すよう配置してなり、該バンクが車両前方を向くように
車体フレームに搭載された自動二輪車用Ｖ型２サイクル
２気筒エンジンに混合気を供給する吸気装置において、
クランクケースの上記バンク内部分に左，右のクランク
室に連通する左，右一対の吸気口を車幅方向に隣接する
ように形成し、該各吸気口のクランク室内側にリードバ
ルブを、クランク室外側に気化器をそれぞれ配設し、上
記各吸気口の幅方向中心を左，右の気筒の中心線より外
側に偏位させるとともに、上記各気化器を車両前側の間
隔が広くなるよう斜め外側に向けて配置したことを特徴
とする自動二輪車用Ｖ型２サイクル２気筒エンジンの吸
気装置。1. A V-type two-stroke two-cylinder engine for a motorcycle mounted on a body frame such that a pair of left and right cylinders are arranged so as to form a bank of a predetermined angle, and the banks face forward of the vehicle. In an intake device for supplying an air-fuel mixture,
A pair of left and right intake ports communicating with the left and right crank chambers are formed adjacent to each other in the width direction of the vehicle in a portion of the bank inside the bank of the crankcase. A carburetor is disposed on the outside of the vehicle, and the center in the width direction of each of the intake ports is deviated outside the center line of the left and right cylinders. An intake device for a V-type two-cycle two-cylinder engine for a motorcycle, wherein the intake device is arranged to face outward.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1162092A JP2716802B2 (en) | 1989-06-23 | 1989-06-23 | V-type two-cycle two-cylinder engine for motorcycles |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1162092A JP2716802B2 (en) | 1989-06-23 | 1989-06-23 | V-type two-cycle two-cylinder engine for motorcycles |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH0326822A JPH0326822A (en) | 1991-02-05 |
| JP2716802B2 true JP2716802B2 (en) | 1998-02-18 |
Family
ID=15747923
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP1162092A Expired - Fee Related JP2716802B2 (en) | 1989-06-23 | 1989-06-23 | V-type two-cycle two-cylinder engine for motorcycles |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2716802B2 (en) |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5946324A (en) * | 1982-10-29 | 1984-03-15 | Honda Motor Co Ltd | V-type internal-comustion engine for motorcycle |
| JP2525394B2 (en) * | 1987-02-28 | 1996-08-21 | スズキ株式会社 | V-type 2-cycle engine intake system |
-
1989
- 1989-06-23 JP JP1162092A patent/JP2716802B2/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| JPH0326822A (en) | 1991-02-05 |
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