JPS5835227A - Spark-ignition 2-cycle engine - Google Patents

Abstract

PURPOSE:To improve intake and scavenge efficiency, by injecting high pressure water into a working chamber in an explosion stroke, and discharging blowing gas from a pressure ring in the explosion stroke from exhaust ports in the lower part of a cylinder wall. CONSTITUTION:A water injection port 14 and exhaust ports 12 are provided respectively in upper and lower walls of a cylinder 1 in a uniflow overhead valve intake-scavenge type engine, while plural relief holes 17 extended through under a pressure ring 18, are provided in the periphery of a piston 2 and connected to relief grooves 16 in a skirt wall surface of the piston 2. Further a particular bowl-shaped combustion and swirl forming chamber 7 formed between an expansion chamber 8 and intake and scavenge valves 4, is formed with the wall surface fully to a circular arc surface, while the opening is formed to a slightly reduced long and narrow shape. In this way, high pressure water can be injected immediately after reaction of combustion, and the internal pressure in the cylinder 1 can be increased by the steam pressure, then the exhaust ports 12 can be located to the lower part, thus a longer effective stroke can be obtained.

Description

【発明の詳細な説明】 本発明は高渦流、高速燃焼室を有する火花点火式２サイ
クル機関に関する。DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a spark-ignited two-stroke engine having a high vortex, high velocity combustion chamber.

近年世界的なエネルギー不足などにより原油などのａｌ
ｌや代替エネルギー開発が深刻化しており、省エネルギ
ー化が大きな社会ｒＩＲＩｌｉになっている。そして、
自動車等ではより熱効率の高いエンジンが要求されるよ
うになっている。In recent years, due to global energy shortages, crude oil and other alkaline
The development of l and alternative energy is becoming more and more serious, and energy conservation has become a major social issue. and,
Engines with higher thermal efficiency are increasingly required for automobiles and the like.

一方自動ｎ■の排ガスによる公害が社会問題化し、汎用
の４サイクル機関では排ガスを浄化するために、一般使
用時には成るべく燃料を薄くして排ガス中の未燃成分を
減らしているのが大勢をしめるようになってきている。On the other hand, pollution caused by exhaust gas from automatic engines has become a social problem, and in order to purify the exhaust gas of general-purpose four-stroke engines, many people use as thin a fuel as possible during general use to reduce unburned components in the exhaust gas. It's starting to get tighter.

このように空燃比を薄くした場合、火炎伝播速度が遅（
なる。そこで、吸気時にスワール（回転流）を加えたり
、副燃焼室を設けて副燃焼室からでる噴出流やスキッシ
ュ゛等で出来るだけ速く撹拌燃焼をさせたり、ｔＭ焼室
における火炎伝播距離を短かくするような燃焼室形状を
工夫したりして燃費の向上等を図っており、これにより
かなりの効果を上げることに成功してい　、る。− ところが、４サイクル機、１ｍ！Ｉの場合、ピストン速
度が速いため、燃焼工程＃闇が短かく、点火時期を早め
なければならず、排気バルブの開き始め時期が甲く、（
平均で約下死点前５５°前後が多い）コンロッドの慣性
も大きいなど、４サイクル機関では特有の欠点がある。When the air-fuel ratio is made lean in this way, the flame propagation speed is slow (
Become. Therefore, we added a swirl (rotating flow) during intake, created a sub-combustion chamber and used the jet flow and squish coming out of the sub-combustion chamber to stir combustion as quickly as possible, and shortened the flame propagation distance in the tM combustion chamber. Efforts have been made to improve fuel efficiency by devising the shape of the combustion chamber to make it more efficient, and have succeeded in achieving considerable results. - However, a 4-cycle machine is 1m! In the case of I, the piston speed is high, the combustion process #darkness is short, the ignition timing has to be advanced, and the timing at which the exhaust valve starts opening is fast.
4-cycle engines have their own drawbacks, such as the high inertia of the connecting rod (often around 55 degrees before bottom dead center on average).

またディーゼル機関の場合は燃焼が緩慢なために、ピス
トン往復機関の理想である上死点付近で早く燃焼させる
という点で欠ける所がある。Also, in the case of diesel engines, combustion is slow, so they lack the ability to burn quickly near top dead center, which is the ideal of piston reciprocating engines.

その証明として回転を上げると不完全燃焼を起こすこと
が判明している。　。As proof of this, it has been found that increasing the speed causes incomplete combustion. .

２サイクル機関の場合は４・サイクル機関のように独立
した排気行程を持たないため、その掃気効率が性能に太
き（影響する。Two-cycle engines do not have an independent exhaust stroke like four-stroke engines, so their scavenging efficiency has a large effect on performance.

掃気方法としては大別してループ掃気方式、クロス掃気
方式、それにユニフロ掃気方式があげられ、ループ掃気
方式及びクロス掃気方式では排気孔をシリンダーの比較
的高い位置に設けなければならないところから、ピスト
ン有効行程が短かくなりやすい欠点がある。Scavenging methods can be roughly divided into loop scavenging, cross scavenging, and uniflow scavenging. In loop scavenging and cross scavenging, the exhaust hole must be installed at a relatively high position in the cylinder, so the effective stroke of the piston is It has the disadvantage that it tends to be short.

一方、ユニフロ掃気方式には排気がシリンダー頭部の弁
から排出され、新気がシリンダー下部壁の掃気孔から供
給される弁排気型と、また反対にシリンダー頭部の弁か
ら新気が供給され、排気をシリンダ一孔から排出させる
弁婚気型があり、弁排気型では高温の排気により弁が加
熱され弁が傷みやすく、また多量の排ガスを頭上弁を通
して排出しなければならないところから、新気容量に比
べ排気容量が大きく大型の弁、または弁数を増やす必要
がある。On the other hand, in the Uniflow scavenging system, exhaust gas is discharged from a valve in the cylinder head, and fresh air is supplied from a scavenging hole in the lower wall of the cylinder. There is a valve exhaust type in which the exhaust gas is discharged from a single hole in the cylinder.In the valve exhaust type, the valve is easily damaged by heating due to the high temperature exhaust gas, and a large amount of exhaust gas must be discharged through an overhead valve, so it is a new type. It is necessary to use a large valve with a large exhaust capacity compared to the air capacity, or to increase the number of valves.

この点弁棉気型は排気孔がピストンによって開かれるた
め、孔面積が急激に増加し理想的な排気噴出が行われ、
また頭上弁は新気によって冷却されて加熱の心配はない
のであるが、弁の下部に掃気流の影を生じるので渦流の
ため新気、排気の混合を生じＩＭ気効率を低下させる欠
点がある。Since the exhaust hole of this point valve cotton air type is opened by a piston, the hole area increases rapidly and an ideal exhaust blowout is achieved.
In addition, overhead valves are cooled by fresh air and there is no need to worry about heating, but since the shadow of the scavenging air flow is created at the bottom of the valve, there is a disadvantage that the vortex creates a mixture of fresh air and exhaust air, reducing IM air efficiency. .

本発明は上述のように汎用のエンジンの欠点とするとこ
ろを改善し、かつ各エンジンめ利点とするところを極力
取り入れた優秀なエンジンを提供しようとするものであ
る。The present invention aims to improve the drawbacks of general-purpose engines as described above, and to provide an excellent engine that incorporates the advantages of each engine as much as possible.

本発明のエンジンは基本的にはユニフロ頭上弁吸掃気式
の火花点火式２サイクル機関である。The engine of the present invention is basically a spark ignition two-stroke engine with a Uniflow overhead valve intake and scavenge type.

ユニフロ掃気方式の弁掃気型において押下側の掃気流の
影を生ずる渦のために掃排気が混合　５するのを頭上吸
怖気弁下部に形設の特殊形状の燃焼室により解消し、ま
た火花点火式とし、４サイクル機関の半分の回転数で作
動させるものであり、２サイクル機関でありながら各行
程の時間を長く取ることができて効率よく作動させるよ
うにし、圧縮比は上死点手前近くで燃料が層状噴射させ
られるため圧縮熱で自発火を起さない程度に畠圧縮比と
することができ、また回転数が低いことと、排気孔面積
が大きくとれることによって排気孔の位置が低く設定で
きるために吸掃気効率が高く有効行程が最大限に長く設
定でき、また水噴射によって高温既燃ガスの濃度を下げ
る代りに蒸気化の圧力を利用しピストンを押し下げるこ
とになり、更にディーゼル機関と同じ（給気を絞らない
構成のため部分負荷の低速時においてもトルクが大きく
、乗用車、バス、トラックをはじめ広範囲にわたって使
用できるようにしたものである。In the valve scavenging type of the Uniflow scavenging system, the mixing of scavenging and exhaust air due to vortices that create a shadow of the scavenging air flow on the push-down side is eliminated by a specially shaped combustion chamber formed at the bottom of the overhead intake air valve, and spark ignition is also avoided. It operates at half the rotation speed of a 4-cycle engine, and although it is a 2-cycle engine, it can take a long time for each stroke and operate efficiently, and the compression ratio is close to top dead center. Since the fuel is injected in layers, the compression ratio can be set to a level that does not cause spontaneous ignition due to the heat of compression, and the low rotational speed and large exhaust hole area allow the exhaust hole to be located low. This allows for high intake and scavenging air efficiency, allowing the effective stroke to be set as long as possible.Also, instead of reducing the concentration of high-temperature burnt gas by water injection, the pressure of vaporization is used to push down the piston, which further improves the efficiency of diesel engines. (The structure does not throttle the air supply, so it has large torque even at low speeds under partial load, making it suitable for use in a wide range of vehicles, including passenger cars, buses, and trucks.)

以下、本発明の実施例を図面について説明゛する。Embodiments of the present invention will be described below with reference to the drawings.

１はシリンダー、２はピストン、３はシリンダーヘッド
のスキッシュ部で、このスキッシュ部３には吸掃気弁４
が設けられる。1 is a cylinder, 2 is a piston, 3 is a squish part of the cylinder head, and this squish part 3 has an intake and scavenge valve 4.
is provided.

吸１気弁４は通常スプリングにより弁座５に圧着され、
吸掃気管６から膨張室８に進入する吸掃気を制御する。The intake valve 4 is normally pressed onto the valve seat 5 by a spring.
The scavenging air entering the expansion chamber 8 from the scavenging air pipe 6 is controlled.

７は吸掃気弁４と膨張室８間に形成した特殊碗型の燃焼
室兼渦流形成室で、その壁面全体が円弧面で開口が若干
絞り形状で細長形にできている。９はこの燃焼室兼渦流
形成室７゛に通じて設けた燃料供給通路で、この通路９
内に燃料噴射弁１０とその下部に点火プラグ１１を装着
する。７１２はシリンダー下部壁に設けた排気孔で、排
気管１３に連通している。Reference numeral 7 designates a special bowl-shaped combustion chamber/vortex forming chamber formed between the intake and scavenge valve 4 and the expansion chamber 8. The entire wall surface of the chamber is an arcuate surface, and the opening is slightly constricted and elongated. 9 is a fuel supply passage provided to communicate with this combustion chamber/vortex forming chamber 7';
A fuel injection valve 10 and a spark plug 11 are installed below it. Reference numeral 712 denotes an exhaust hole provided in the lower wall of the cylinder, which communicates with the exhaust pipe 13.

１４はシリンダー１の上部壁に開口させた水噴射孔で、
水噴射弁１５を設置し、高圧水噴射源ニ連結すれる。１
６はピストン２の外周面に設けた吹き抜はガス逃し手段
で、排気孔に対応して設けられ、圧力リング１８の下を
潜り抜はピストン壁面に開口する複数個の逃げ穴１７と
、この逃げ穴１７に連結したピストンスカート部壁面長
手方向に凹設した逃げ溝１６とよりなる。14 is a water injection hole opened in the upper wall of cylinder 1;
A water injection valve 15 is installed and connected to a high pressure water injection source. 1
Reference numeral 6 denotes gas relief means provided on the outer peripheral surface of the piston 2, which is provided corresponding to the exhaust hole, and includes a plurality of relief holes 17 that go under the pressure ring 18 and open in the piston wall surface. It consists of an escape groove 16 connected to an escape hole 17 and recessed in the longitudinal direction of the piston skirt wall surface.

本発明は上記の如く構成したものであり、次に作用を説
明する。The present invention is constructed as described above, and its operation will be explained next.

本発明は火花点火式４サイクル機関の半分の速度で作動
させるものであり、第４図に示す行程図に基づいて、そ
の圧縮行程から説明すると、圧縮行程の後期に燃料噴射
弁１０を開いて燃料噴射が行われる。ここで燃料は通路
９を介して先ず渦流形成室７に噴出し層状になって膨張
室８に向う。燃料噴射弁１０が閉じ燃料噴射直接の上死
点手前で点火プラグ１１により火花点火が行なわれて＾
圧縮及び高渦流やスキッシュ等で急速層状燃焼となる。The present invention operates at half the speed of a spark-ignition four-stroke engine, and will be explained from the compression stroke based on the stroke diagram shown in FIG. Fuel injection takes place. Here, the fuel is first injected into the vortex forming chamber 7 through the passage 9 and then flows into the expansion chamber 8 in the form of a layer. The fuel injection valve 10 closes and spark ignition is performed by the spark plug 11 directly before the top dead center of fuel injection.
Rapid stratified combustion occurs due to compression, high vortices, squish, etc.

そしてピストン２が下降を開始し、水噴射孔１４位置を
通過したところで水噛射弁１５が開き適量の高圧水噴射
を行なう。この水噴射は時期的に燃焼反応が終った直後
になされ、従って第４図に示すように高温既燃ガスに対
する水噴射で水の蒸発がおこり、気化熱によってガス温
度を下げる代りにシリンダー内圧は蒸気圧により高めら
れてピストンを押し下げるカを倍加する。ここで排気孔
１２が開かれる間、ピストン周りから吹き抜ける蒸気及
びガスは吹き抜はガス逃し孔１７及び逃し溝１６を経て
排気孔１２に誘導排出される。そして、ピストン２によ
って排出孔１２が開かれると排気は一気にシリンダー外
に排出されることになり、その少し後、頭上吸掃気弁４
が燃焼室兼渦流形成室７の半分程の位置まで開かれ、燃
焼室兼渦流形成室７において渦流をともなった掃気新気
入替が排気孔１２が閉じるまで行われ、排気口１２が閉
じて後、若干の過給を行（１＠掃気弁４を閉じＩｆ縮行
程へ移り、前に！同様の′Ｖイクルを繰り返す。Then, the piston 2 starts descending, and when it passes the water injection hole 14 position, the water injection valve 15 opens and sprays an appropriate amount of high-pressure water. This water injection is performed immediately after the combustion reaction has finished, and therefore, as shown in Figure 4, water evaporation occurs when water is injected into the high-temperature burnt gas, and instead of lowering the gas temperature due to the heat of vaporization, the cylinder internal pressure decreases. Increased by steam pressure, it doubles the force pushing down the piston. While the exhaust hole 12 is opened, steam and gas blowing from around the piston are guided and discharged into the exhaust hole 12 through the gas relief hole 17 and the relief groove 16. Then, when the exhaust hole 12 is opened by the piston 2, the exhaust gas is discharged out of the cylinder at once, and a little later, the overhead air intake and scavenge valve 4
is opened to about half of the combustion chamber/vortex forming chamber 7, scavenging fresh air is exchanged with a vortex in the combustion chamber/vortex forming chamber 7 until the exhaust port 12 is closed, and after the exhaust port 12 is closed, , perform a slight supercharging (1@ Close the scavenging valve 4, move to the contraction stroke, and repeat the same 'V cycle as before).

ところで、従来より吸入空気、燃料、または混合気に水
を添加することによって、排ガス中の有害成分とくにＮ
Ｏｘを抑制し、かつ燃焼効率の向上という効果もあるこ
とが知ら１ている。By the way, by adding water to intake air, fuel, or mixture, it has been possible to reduce harmful components in exhaust gas, especially N.
It is known that it has the effect of suppressing Ox and improving combustion efficiency1.

しかし、ここでの水噴射については、はとんどが点火爆
発前に水が供給されるために気化熱により燃焼温度が低
下し燃焼速度が遅く水噴射の供給利用の限界が低いこと
が実験などで分っている。また水蒸気がピストン側面か
らクランク室に入り、クランクオイルを乳化させたり、
クランク室の錆の原因になるなど実用上の難点が多いも
のとされている。However, with regard to water injection here, experiments have shown that because the water is supplied before the ignition explosion, the combustion temperature decreases due to the heat of vaporization, the combustion speed is slow, and the limit of water injection supply utilization is low. It is known from such things. Also, water vapor enters the crank chamber from the side of the piston and emulsifies the crank oil.
It is said to have many practical drawbacks, such as causing rust in the crank chamber.

本発明の場合は、燃焼反応の終ったガスに向って水を噴
射するため多量の水噴射ができ、また蒸気の吹き抜けは
、ピストン側面に形設した逃し穴から逃し溝を通って排
気孔へと外部′に排出されるもので、オイル劣化、発錆
などの原因を尽く解決できたものである。In the case of the present invention, a large amount of water can be injected because water is injected toward the gas that has completed the combustion reaction, and the steam blows through from the relief hole formed on the side of the piston to the exhaust hole through the relief groove. The cause of oil deterioration, rusting, etc. has been completely resolved.

またシリンダーヘッドの部分には特殊碗型の燃焼室兼渦
流形成室を設けて、燃料噴射及び点火もこの渦流形成室
を介して行うようにしたから、急速層状燃焼を実現して
理想的燃焼をなさしめ、更にこの燃焼反応が終了した時
点でシリンダー壁に設けた水噴射孔からシリンダー内に
多量の水噴射を行い燃焼ガスの熱をうばって水の蒸発に
よりシリンダー内圧を高めるようにしだから、燃料の発
生熱が有効に利用できて高温燃焼ガスの滞留時間が短く
、シリンダー壁との温度差も少なくなり輻射熱損失も減
少し熱効率を極限まで高めることができ、排ガス浄化上
からも有効なものであり、また掃気新気入替時にも渦流
形成室で新気の積極的渦流を生起して掃気作用をなし、
新気排気の混合が少なく、しかも給気を絞らない構成の
ため、部分負荷の低速時においてもトルクが大きく、ま
た高温高圧縮比であるため、多種類の燃料が使用可能で
あり、更に回転数が低くピストンコンロッドの慣性によ
る機械的損失ら少ない等の帰れたすくけた効果を奏する
。In addition, a special bowl-shaped combustion chamber and vortex forming chamber is installed in the cylinder head, and fuel injection and ignition are also performed through this vortex forming chamber, achieving rapid stratified combustion and ideal combustion. Furthermore, when this combustion reaction is completed, a large amount of water is injected into the cylinder from the water injection hole provided in the cylinder wall to dissipate the heat of the combustion gas and increase the pressure inside the cylinder through water evaporation. The generated heat can be used effectively, the residence time of high-temperature combustion gas is shortened, the temperature difference with the cylinder wall is reduced, radiant heat loss is also reduced, and thermal efficiency can be maximized, and it is also effective in purifying exhaust gas. Also, when exchanging fresh air for scavenging, an active vortex of fresh air is generated in the vortex forming chamber to perform a scavenging effect.
Because the mixture of fresh air exhaust is small and the supply air is not throttled, the torque is large even at low speeds under partial load.The high temperature and high compression ratio means that many types of fuel can be used, and even higher rotation speeds are achieved. Since the number of piston connecting rods is small, mechanical loss due to inertia of the piston connecting rod is also small, and other benefits are achieved.

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

図面は本発明の実施例を示し、第１図はシリンダーの縦
断面図、第２図はシリンダーヘッド部正面図、第３図は
ピストンの部分断面図、第４図は行程線図、第５図はシ
リンダー内圧力変化および温度変化図である。 １・・・シリンダ、　　　　　２・・・ピストン、３・
・・スキッシュ部、　　４・・・吸撞気弁、５・・・弁
座、　　　　　　６−・・吸掃気管、７・・・燃焼室兼
渦流形成室、８・・・膨張室、９・・・燃料供給通路、
　１０・・・燃料噴射弁、１１・・・点火プラグ、　　
１２・・・排気孔、　。 １３・・・排気管。　　　　１４・・・水噴射孔１５・
・・水噴射弁、　　　１６・・・逃し溝、１７・・・逃
し孔、　　　　　１８・・・圧力リング、１９・・・オ
イルリング。 俸２図 館３ｖＲ ｆＩ！−１ｍｌ 体５１１ 手続補正書（自発） 昭和５６年ｌＯ月　５　日 特許庁長官島田要衝　殿 １、事件の表示　昭和５６　年　特　許　願第１８３８
７８　号２、発明の名称　　火花点火式２サイクル機関
３、補正をする者事件との関係　特　　許　出願人４、
　代　　理　　人　　〒６５０ ５、補正指令の日付　昭和　　年　　月　　日６・　補
正（７）対象　　明細書中発明の詳細な説明の欄手続補
正書（方幻 昭和６７年　２’ｎＢＬｌ 特許庁長官島田要衝　殿 ２、発明の名称　　火花点火式２サイクル機閤３、補正
をする者事件との関係　特　　許　出願人４、　代　　
理　　人　　〒６５０ □−The drawings show an embodiment of the present invention; FIG. 1 is a longitudinal sectional view of the cylinder, FIG. 2 is a front view of the cylinder head, FIG. 3 is a partial sectional view of the piston, FIG. 4 is a stroke diagram, and FIG. The figure is a diagram of pressure changes and temperature changes within the cylinder. 1...Cylinder, 2...Piston, 3...
... Squish portion, 4... Air intake valve, 5... Valve seat, 6-... Air intake and scavenging pipe, 7... Combustion chamber/vortex forming chamber, 8... Expansion chamber, 9...・Fuel supply passage,
10...Fuel injection valve, 11...Spark plug,
12...Exhaust hole. 13...Exhaust pipe. 14... Water injection hole 15.
... Water injection valve, 16 ... Relief groove, 17 ... Relief hole, 18 ... Pressure ring, 19 ... Oil ring. Salary 2 Museum 3vR fI! -1ml Body 511 Procedural amendment (spontaneous) October 5, 1980 Yoko Shimada, Commissioner of the Japan Patent Office 1, Indication of the case 1983 Patent Application No. 1838
78 No. 2, Title of the invention Spark ignition two-cycle engine 3, Relationship with the case of the person making the amendment Patent Applicant 4.
Agent 〒650 5, Date of amendment order: Showa year, month, day 6, Subject of amendment (7): Detailed explanation of the invention in the specification Procedural amendment (Hogen, 1986 2'nBLl Mr. Yosho Shimada, Commissioner of the Japan Patent Office) 2. Title of the invention Spark ignition two-cycle machine 3. Relationship with the case of the person making the amendment Patent Applicant 4.
Person 〒650 □−

Claims (1)

【特許請求の範囲】[Claims] 高圧縮比、＾温、かつ高渦流で急速層状燃焼を起させ、
燃焼反応を♀く終らせるユニフロ非対称捧気形式頭上吸
捧気＃型２サイクル機関において、−発工程にある作動
室を構成するシリンダ壁に水噴射弁を含む高圧水噴射手
段を設け、また爆発行程に於いて圧力リングを通過した
吹き抜はガスをシリンダ壁下部に開設の排気口に排出す
べくピストン外周面にガス逃し手段を設けたことを特徴
とする火花点火式２サイクル機関。Rapid stratified combustion is caused by high compression ratio, temperature, and high vortex flow.
In the UNIFLO asymmetrical air intake type #2-cycle engine, which completes the combustion reaction quickly, a high-pressure water injection means including a water injection valve is installed on the cylinder wall constituting the working chamber during the combustion process, and the explosion A spark ignition two-stroke engine characterized in that a gas relief means is provided on the outer circumferential surface of the piston so that the gas that has passed through the pressure ring during the stroke is discharged to an exhaust port provided at the bottom of the cylinder wall.