JP2009133296A

JP2009133296A - Oxygen injection type four-cycle internal combustion engine

Info

Publication number: JP2009133296A
Application number: JP2007341729A
Authority: JP
Inventors: Shuichi Kitamura; 修一北村
Original assignee: Individual
Current assignee: Individual
Priority date: 2007-11-28
Filing date: 2007-11-28
Publication date: 2009-06-18

Abstract

<P>PROBLEM TO BE SOLVED: To remarkably improve thermal efficiency by completely preventing generation of NOx by not making the air a working fluid, preventing output decline even in the case an expansion ratio to compression is increased for improvement of the thermal efficiency, reducing pump loss and friction loss, and reducing cooling loss by lowering the maximum combustion temperature. <P>SOLUTION: The four-cycle internal combustion engine comprises a poppet valve for circulation and blockage of a burned gas to a cylinder head, having steps of intake, compression, expansion and exhaustion of a working fluid. It comprises an oxygen supply container 15, an oxygen jetting valve 38 for jetting the oxygen from the oxygen supply container 15 and a fuel jetting valve 37 for jetting a fuel, and a cooling device 29 for cooling the burned gas discharged from the inside of the cylinder via the poppet valve 21. The burned gas cooled down by the cooling device 29 is introduced into the cylinder via the poppet valve 25. By changing the valve closing time of the poppet valve 25 by a variable valve gear 4 according to the operation state of the engine, the real compression ratio is changed. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

Detailed Description of the Invention

Industrial application fields

本発明は空気を吸入する代りに酸素供給容器からの酸素をシリンダー内に噴射する酸素噴射式４サイクル内燃機関に関する。 The present invention relates to an oxygen injection type four-cycle internal combustion engine in which oxygen from an oxygen supply container is injected into a cylinder instead of sucking air.

一般に４サイクル内燃機関では空気を作動流体として使っている為、ＮＯｘの発生は避けられず、大気汚染の元凶となっていた。
又、４サイクルディーゼル機関では圧縮比が高い事による摩擦損失が大であり、最高燃焼温度が高い事による冷却損失も大で、これらの理由により熱効率の改善が困難であった。一方、４サイクル火花点火式内燃機関でも最高燃焼温度が高い事による冷却損失が大であり、シリンダー内に吸入される空気を絞って出力を制御する事によるポンプ損失が大で、これらの理由により熱効率の改善が困難であった。更には前記４サイクルディーゼル機関及び４サイクル火花点火式機関では圧縮比に対して膨張比を大として高膨張比化すると、有効吸入行程の減少により出力低下となり、この為、熱効率の改善が困難であった。In general, in a four-cycle internal combustion engine, air is used as a working fluid, so generation of NOx is unavoidable and has become a cause of air pollution.
Further, in a 4-cycle diesel engine, the friction loss due to the high compression ratio is large, and the cooling loss due to the high maximum combustion temperature is also large. For these reasons, it is difficult to improve the thermal efficiency. On the other hand, the four-cycle spark ignition type internal combustion engine has a large cooling loss due to the high maximum combustion temperature, and the pump loss due to the control of the output by restricting the air sucked into the cylinder is large. Improvement of thermal efficiency was difficult. Furthermore, in the 4-cycle diesel engine and the 4-cycle spark ignition engine, if the expansion ratio is increased with respect to the compression ratio and the expansion ratio is increased, the output is reduced due to a decrease in the effective intake stroke, which makes it difficult to improve the thermal efficiency. there were.

Problems to be solved by the invention

本発明の目的は空気を作動流体としない事によってＮＯｘの発生を根源から断ち切る事であり、熱効率の改善の為に圧縮比に対し膨張比を大として高膨張比化しても、出力の低下を招かない様にすることである。更にはポンプ損失や摩擦損失を減らし、最高燃焼温度を下げて冷却損失を減らし、以って熱効率の大幅改善を図ることである。 The object of the present invention is to cut off the generation of NOx from the source by not using air as a working fluid. Even if the expansion ratio is increased with respect to the compression ratio to improve the thermal efficiency, the output is reduced. Do not invite them. Furthermore, the pump loss and friction loss are reduced, the maximum combustion temperature is lowered, the cooling loss is reduced, and the thermal efficiency is greatly improved.

Means to solve the problem

本発明は上記目的を達成する為、作動流体の吸気・圧縮・膨張・排気の各行程を有し、シリンダーヘッドに既燃ガスの流通及び遮断を司どるポペット弁を備えた４サイクル内燃機関において、酸素供給容器を備え、前記酸素供給容器からの酸素を噴射する酸素噴射弁と燃料を噴射する燃料噴射弁とを備え、更にシリンダー内からポペット弁を介して排出された既燃ガスを冷却する冷却器を備えてこの冷却器により冷却された既燃ガスをポペット弁を介してシリンダー内に導入する様にし、機関の運転状態に応じてポペット弁の閉弁時期を可変動弁装置により変化させて実圧縮比を可変化する様に構成した。 In order to achieve the above object, the present invention provides a four-cycle internal combustion engine having intake, compression, expansion, and exhaust strokes of a working fluid and a poppet valve that controls the flow and shutoff of burned gas in a cylinder head. An oxygen supply container, an oxygen injection valve for injecting oxygen from the oxygen supply container and a fuel injection valve for injecting fuel, and further cooling the burned gas discharged from the cylinder through the poppet valve A combustor is provided so that the burned gas cooled by the cooler is introduced into the cylinder via the poppet valve, and the valve closing timing of the poppet valve is changed by a variable valve operating system according to the operating state of the engine. The actual compression ratio is made variable.

図１（イ）は本発明による酸素噴射式４サイクル内燃機関の一実施例で（ここではディーゼル機関とする）、１はその本体を示し、通常は多気筒機関であり、その一断面を図１（ロ）に、図１（ロ）を上方から見て図１（ハ）にポペット弁２１、２５、燃料噴射弁３７、酸素噴射弁３８等のレイアウトを示す。酸素供給容器１５（例えば３５０気圧程度に圧縮された酸素が充填された酸素ボンベから成る）からの酸素はプレッシャーレギュレーター１６によって一定圧力に調整された後にサージタンク１７に到り、更に酸素噴射弁３８からシリンダー内へ噴射される。この場合、酸素噴射弁３８は吸入通路３２に配置しても良い。
サージタンク１７には圧力センサー１８が取り付けられ、酸素噴射弁３８へ供給する酸素圧力を検出する手段として用いられる。シリンダーヘッドには燃料を噴射する燃料噴射弁３７が備えられ、更に作動流体（既燃ガス、酸素など）の流通及び遮断を司どるポペット弁２１、２５が備えられている。ポペット弁２１は排気用、ポペット弁２５は吸気用で、各々２個づつ備えられている。この場合、ポペット弁２１、２５は大部分がピストン１９に形成された燃焼室２０の範囲内に収まる様にしてピストン１９との干渉を回避するバルブリセス部を小さくする様に工夫する（図１（ニ）の様にポペット弁２１′、２５′が１個づつの場合は燃焼室２０′は楕円形とするのが良い）。３８は酸素噴射弁で、シリンダー内に酸素を噴射する。ポペット弁２１はカム軸２２に形成されたカム２３により駆動され、ポペット弁２５は同じくカム軸２２に形成された図示しないカムによりロッカーアーム２４を介して駆動される。燃料噴射弁３７を含む燃料噴射装置としては例えばコモンレール方式（蓄圧室方式）を用いる事ができる。
排気行程（ピストン１９は上昇）ではポペット弁２１は開いており、シリンダー内の既燃ガスはポペット弁２１、排出通路２６（各気筒毎に備えられる）を介してサージタンク３１の方へ流れ、少量の部分が放出通路２８の方に流れる様になっている（大気中に放出）。続く吸気行程（ピストン１９は下降）ではポペット弁２１は閉じ、ポペット弁２５が開いて連絡通路３０を介してサージタンク３１に導入された既燃ガスが吸入通路３２（各気筒毎に備えられる）、ポペット弁２５を介してシリンダー内に吸入され、圧縮行程（ピストン１９は上昇）ではポペット弁２１、２５は閉じ、シリンダー内に閉じ込められた既燃ガスがピストン１９によって圧縮され、更に圧縮行程中の適当な時期に酸素噴射弁３８から酸素が噴射され（酸素噴射弁３８を吸入通路３２に備える場合は吸気行程中に酸素を噴射する）、上死点又はその付近の適当なクランク角度で酸素を含む燃焼室２０内の圧縮された高温の気体中に燃料噴射弁３７から燃料を噴射して着火・燃焼を行なわせる様にしている。この後、膨張行程に移り、ピストン１９は下降により燃焼室２０内の高温・高圧の燃焼ガスが膨張し、かくしてクランク軸２回転毎に１回の膨張仕事が得られる。冷却器２９は排出通路２６、サージタンク２７からの既燃ガスが通る多数のパイプを有し、その周囲をクーラントが取り囲む構造で、この既燃ガスをクーラントとの熱交換により冷却して吸入通路３２の方へ送る為のもので（クーラントや吸収した熱は最終的にラジエターから大気中に放出される）、冷却器２９をバイパスするバイパス通路３６及び制御弁３３（冷却器２９の入口部３０′に備えられている）、３４が備えられ、制御弁３３、３４の開度を各々調整する事によって吸入通路３２、ポペット弁２５を介してシリンダー内に吸入される既燃ガスの温度を制御する様にしている。
即ち、制御弁３３、３４はリンク機構等により互いに連動し合い（カムを介して連動させても良い）、制御弁３３の開度を大とし、制御弁３４の開度を小とする程、ポペット弁２５を介してシリンダー内に吸入される既燃ガスの温度は低下する、制御弁３３、３４は後述する様にエンジン負荷、回転速度、冷却水温度等によってその開度が最適制御されるが、これは制御弁３４を駆動する電動アクチュエーター３５（モーター）によって為され、電子制御ユニット１４（以後ＥＣＵ１４）は予め与えられた所定の特性に基づいて制御弁３４の開度を演算し、電動アクチュエーター３５の回転角を制御する、尚、冷却器２９により冷却されると言ってもポペット弁２５を介してシリンダー内に吸入される既燃ガスの温度は空気を吸入する場合に比し十分に高いから、低圧縮比化は可能であり、従って前記シリンダー内に吸入される既燃ガスの温度を制御する制御弁３３、３４、バイパス通路３６は必要不可欠なものではない、制御弁３４、３３については図１（ホ）の如く１つの制御弁３９により同じ効果をもたらす事ができる（構造簡単）、４は可変動弁装置としての、開弁期間は変えずにポペット弁２１、２５の開閉時期を変化させる公知のバルブタイミング可変装置を示し、ハウジング６とローター７とから成り、ハウジング６はプーリー５（又はスプロケット）とボルトにより結合、一体化され、ローター７はカム軸２２とボルトにより結合、一体化されており、プーリー５はクランク軸２によりベルト３（又はチェーン）を介して回転比１／２に減速して駆動される。ハウジング６及びローター７により進角室８と遅角室９とが形成され、油圧制御弁１０からの作動油が供給される。
油圧制御弁１０は図示しない油圧ポンプから油圧が供給され、後述するＥＣＵ１４からの出力信号により軸方向への移動量が電磁ソレノイドにより駆動制御されるプランジャー１１と、スプール弁１２とバネ１３とを有しており、バネ１３の反発力とプランジャー１１の押圧力とが均衡する位置でスプール弁１２が位置決めされる様になっている。ＥＣＵ１４には所定のクランク角毎にクランク角信号を出力するクランク角センサーからの信号、所定のカム角毎にカム角信号を出力するカム角センサーからの信号が入力される。ＥＣＵ１４はカム角センサーから出力される回転角パルスとクランク角センサーから出力されるクランク角パルスとの間の出力位相差に基づきカム位相角を検出する事ができる。ＥＣＵ１４はローター７の、即ちカム軸２２のクランク軸２に対する位相角が目標値となる様に油圧制御弁１０に制御信号を出力する。ＥＣＵ１４は検出したカム位相角をフィードバック信号として取り込み、その制御上の目標位相角との間の偏差に応じて油圧制御弁１０の駆動デューティ比率をフィードバック制御する。油圧制御弁１０はＥＣＵ１４から指示されるデューティ比率に応じて電磁ソレノイドを駆動して進角室８、遅角室９に対する油圧の給排を調整し、カム軸２２を目標位相角まで進角又は遅角、或いは中立に保持する（任意のカム位相角に固定）。
ＥＣＵ１４はＲＯＭ、ＲＡＭ、ＣＰＵ、入力ポート、出力ポート等から成るマイクロコンピューターを中心として構成され、これらは双方向性バスによって相互に接続されている。ＥＣＵ１４にはエンジンの運転状態の把握に必要なパラメーター用の各種センサー、例えば所定のクランク角毎にクランク角信号を出力するクランク角センサー、所定のカム角毎にカム角信号を出力するカム角センサー、アクセル開度を検出するアクセルセンサー、エンジン冷却水温を検出する水温センサー、大気圧センサー、サージタンク１７内の酸素圧力を検出する圧力センサー１８、排ガス中に酸素濃度を検出するＯ_２センサー、ノックセンサー等からの各出力信号が対応するＡ／Ｄコンバーターを介して入力ポートに送信される。尚、エンジン回転速度は前記クランク角センサーからの信号により知る事ができる。又、出力ポートは燃料噴射弁３７、酸素噴射弁３８、プレッシャーレギュレーター１６、油圧制御弁１０、電動アクチュエーター３５（４０）等に各々に対応する駆動回路を介して接続され、各々の制御信号を送信する。ＲＯＭには燃料噴射弁３７、酸素噴射弁３８の噴射量や噴射時期を決定する為の制御ルーチン等のエンジンを制御する為の制御ルーチン（図７の場合は点火プラグ５３への通電時間を制御する為の制御ルーチンも）やそれらに用いられる制御値を含むマップが記憶されている。ＲＡＭには上記センサーからの出力信号やＣＰＵの演算結果が記憶されている。ＲＡＭに記憶されている各々のデーターはエンジン回転速度センサーが信号を出力する毎に最新のデータに書き換えられる。ＣＰＵはＲＯＭに記憶されたアプリケーションプログラムに従って動作し、燃料や酸素の噴射制御（図７の場合は点火時期制御も）等を実行する。FIG. 1 (a) shows an embodiment of an oxygen injection type four-cycle internal combustion engine according to the present invention (here, a diesel engine). Reference numeral 1 denotes a main body, which is usually a multi-cylinder engine, and shows a cross section thereof. FIG. 1 (b) shows the layout of the poppet valves 21 and 25, the fuel injection valve 37, the oxygen injection valve 38, and the like as viewed from above. Oxygen from the oxygen supply container 15 (for example, consisting of an oxygen cylinder filled with oxygen compressed to about 350 atm) is adjusted to a constant pressure by the pressure regulator 16 and then reaches the surge tank 17, and further the oxygen injection valve 38. Is injected into the cylinder. In this case, the oxygen injection valve 38 may be disposed in the suction passage 32.
A pressure sensor 18 is attached to the surge tank 17 and is used as means for detecting the oxygen pressure supplied to the oxygen injection valve 38. The cylinder head is provided with a fuel injection valve 37 for injecting fuel, and further provided with poppet valves 21 and 25 for controlling the flow and blocking of the working fluid (burned gas, oxygen, etc.). Two poppet valves 21 are provided for exhaust, and two poppet valves 25 are provided for intake. In this case, the poppet valves 21 and 25 are devised so that most of the poppet valves 21 and 25 are within the range of the combustion chamber 20 formed in the piston 19 so as to reduce the valve recess portion that avoids interference with the piston 19 (FIG. 1 ( When the poppet valves 21 'and 25' are one by one as in (d), the combustion chamber 20 'may be elliptical). An oxygen injection valve 38 injects oxygen into the cylinder. The poppet valve 21 is driven by a cam 23 formed on the cam shaft 22, and the poppet valve 25 is driven via a rocker arm 24 by a cam (not shown) formed on the cam shaft 22. As a fuel injection device including the fuel injection valve 37, for example, a common rail method (accumulation chamber method) can be used.
In the exhaust stroke (the piston 19 is raised), the poppet valve 21 is open, and the burned gas in the cylinder flows toward the surge tank 31 via the poppet valve 21 and the discharge passage 26 (provided for each cylinder) A small portion flows toward the discharge passage 28 (released into the atmosphere). In the subsequent intake stroke (piston 19 descends), the poppet valve 21 is closed, the poppet valve 25 is opened, and the burned gas introduced into the surge tank 31 through the communication passage 30 is provided in the intake passage 32 (provided for each cylinder). In the compression stroke (piston 19 is lifted), the poppet valves 21 and 25 are closed and the burned gas trapped in the cylinder is compressed by the piston 19 and further during the compression stroke. Oxygen is injected from the oxygen injection valve 38 at an appropriate time (if the oxygen injection valve 38 is provided in the intake passage 32, oxygen is injected during the intake stroke), and oxygen is supplied at an appropriate crank angle at or near top dead center. The fuel is injected from the fuel injection valve 37 into the compressed high-temperature gas in the combustion chamber 20 including the ignition and combustion. Thereafter, the process proceeds to an expansion stroke, and the piston 19 descends, whereby the high-temperature and high-pressure combustion gas in the combustion chamber 20 expands. Thus, one expansion work is obtained for every two rotations of the crankshaft. The cooler 29 has a large number of pipes through which the burned gas from the discharge passage 26 and the surge tank 27 passes, and a coolant surrounds the periphery of the pipe. The intake passage is cooled by heat exchange with the coolant. 32 (the coolant and absorbed heat are finally released from the radiator into the atmosphere), and a bypass passage 36 that bypasses the cooler 29 and a control valve 33 (an inlet 30 of the cooler 29). 34), and the temperature of burned gas sucked into the cylinder via the suction passage 32 and the poppet valve 25 is controlled by adjusting the opening degree of the control valves 33 and 34, respectively. I try to do it.
That is, the control valves 33 and 34 are interlocked with each other by a link mechanism or the like (may be interlocked via a cam), the larger the opening degree of the control valve 33 and the smaller the opening degree of the control valve 34, The temperature of the burned gas sucked into the cylinder through the poppet valve 25 is decreased. The opening degree of the control valves 33 and 34 is optimally controlled by the engine load, the rotational speed, the cooling water temperature and the like as will be described later. However, this is done by an electric actuator 35 (motor) that drives the control valve 34, and the electronic control unit 14 (hereinafter referred to as ECU 14) calculates the opening degree of the control valve 34 based on predetermined characteristics given in advance. The rotation angle of the actuator 35 is controlled. Note that the temperature of the burned gas sucked into the cylinder via the poppet valve 25 is the same as that when the air is sucked. However, since the compression ratio is sufficiently high, it is possible to reduce the compression ratio. Therefore, the control valves 33 and 34 and the bypass passage 36 for controlling the temperature of the burned gas sucked into the cylinder are not indispensable. 1 and 3 can provide the same effect (one structure is simple) as shown in FIG. 1 (e) (simple structure), 4 is a variable valve operating device without changing the valve opening period, 25 shows a known valve timing variable device for changing the opening and closing timing of 25, which comprises a housing 6 and a rotor 7. The housing 6 is coupled and integrated by a pulley 5 (or sprocket) and a bolt, and the rotor 7 is connected to a camshaft 22. The pulley 5 is coupled and integrated by a bolt, and the pulley 5 is driven by the crankshaft 2 through the belt 3 (or chain) at a speed reduction of 1/2. An advance chamber 8 and a retard chamber 9 are formed by the housing 6 and the rotor 7, and hydraulic oil is supplied from the hydraulic control valve 10.
The hydraulic control valve 10 is supplied with hydraulic pressure from a hydraulic pump (not shown), and includes a plunger 11 that is driven and controlled by an electromagnetic solenoid in accordance with an output signal from an ECU 14 (to be described later), a spool valve 12 and a spring 13. The spool valve 12 is positioned at a position where the repulsive force of the spring 13 and the pressing force of the plunger 11 are balanced. The ECU 14 receives a signal from a crank angle sensor that outputs a crank angle signal for each predetermined crank angle, and a signal from a cam angle sensor that outputs a cam angle signal for each predetermined cam angle. The ECU 14 can detect the cam phase angle based on the output phase difference between the rotation angle pulse output from the cam angle sensor and the crank angle pulse output from the crank angle sensor. The ECU 14 outputs a control signal to the hydraulic control valve 10 so that the phase angle of the rotor 7, that is, the camshaft 22 with respect to the crankshaft 2 becomes a target value. The ECU 14 takes in the detected cam phase angle as a feedback signal, and feedback-controls the drive duty ratio of the hydraulic control valve 10 according to the deviation from the control target phase angle. The hydraulic control valve 10 drives an electromagnetic solenoid according to the duty ratio instructed from the ECU 14 to adjust the supply / discharge of the hydraulic pressure to the advance chamber 8 and the retard chamber 9 and advance the camshaft 22 to the target phase angle. Hold retarded or neutral (fixed to any cam phase angle).
The ECU 14 is mainly configured by a microcomputer including a ROM, a RAM, a CPU, an input port, an output port, and the like, and these are connected to each other by a bidirectional bus. The ECU 14 includes various sensors for parameters necessary for grasping the operating state of the engine, for example, a crank angle sensor that outputs a crank angle signal at every predetermined crank angle, and a cam angle sensor that outputs a cam angle signal at every predetermined cam angle. Accelerator sensor for detecting accelerator opening, water temperature sensor for detecting engine coolant temperature, atmospheric pressure sensor, pressure sensor 18 for detecting oxygen pressure in surge tank 17, O ₂ sensor for detecting oxygen concentration in exhaust gas, knock Each output signal from a sensor or the like is transmitted to an input port via a corresponding A / D converter. The engine speed can be known from a signal from the crank angle sensor. The output port is connected to the fuel injection valve 37, the oxygen injection valve 38, the pressure regulator 16, the hydraulic control valve 10, the electric actuator 35 (40), etc. via the corresponding drive circuits, and transmits the respective control signals. To do. In the ROM, a control routine for controlling the engine, such as a control routine for determining the injection amount and injection timing of the fuel injection valve 37 and the oxygen injection valve 38 (in the case of FIG. 7, the energization time to the spark plug 53 is controlled. And a map including control values used for them is stored. The RAM stores an output signal from the sensor and a calculation result of the CPU. Each data stored in the RAM is rewritten to the latest data every time the engine speed sensor outputs a signal. The CPU operates in accordance with an application program stored in the ROM, and executes fuel and oxygen injection control (in the case of FIG. 7, ignition timing control is also performed).

図２はポペット弁２５、２１の開閉時期変化を示す図で（クランク角で示してある）、ポペット弁２５は吸気用、ポペット弁２１は排気用であり、４サイクル機関であるから各々クランク軸２回転に１回の開閉動作を繰り返し、同一のバルブタイミング可変装置４により駆動されるから、位相変化は各々同一である。エンジンアイドル状態では図２（イ）の如くポペット弁２５（吸気用）は上死点前１０℃Ａで開、下死点後６２℃Ａで閉として実圧縮比（ポペット２５の閉時での圧縮比）を１６程度とし、他方ポペット弁２１（排気用）は下死点前６２℃Ａで開、上死点前１０℃Ａで閉として実膨張比（ポペット弁２１の開時での膨張比）を１６程度とする。一方、制御弁３４は全開又はほぼ全開、制御弁３３は全閉又は若干開く様に電動アクチュエーター３５により制御されている。従って、シリンダー内から排出された排ガスは全部又は殆どバイパス通路３６を通って（冷却器２９を全く又は殆ど通らず）吸入通路３２の方へ送られるから、高温に保たれたままポペット弁２５を介して導入され、かつポペット弁２５の閉弁時において多量にシリンダー内に閉じ込められるから、圧縮端温度（圧縮上死点における燃焼室２０内のガス温度）は低圧縮比ながら十分に高まり、燃料噴射弁３７から噴射された燃料を良好に着火・燃焼させる事ができる。エンジン低負荷域では燃料噴射量も多くなって排ガス温度が高まり、制御弁３４の開度は小さく、制御弁３３の開度が大となる様に制御されるから、吸入通路３２の方へ送られる排ガスは高温ではあるが、冷却器２９により冷却されて適温に保たれ、従って図２（ロ）の如くポペット弁２５の閉弁時期を遅らせて実圧縮比を１４程度としても（この時、ポペット弁２１の開弁時期も遅角し、実膨張比は１７．６位となる）低圧縮比ながら圧縮端温度は十分に高く、噴射された燃料を良好に着火・燃焼させる事ができる。
実圧縮比に対し実膨張比の方が高い為、熱効率の向上が期待できる。エンジン中・高負荷域では燃料噴射量が更に増して排ガスも一層高温となるが、制御弁３４は全閉（又はほぼ全閉）、制御弁３３は全開（又はほぼ全開）となる様に制御されるので、冷却器２９により十分に冷却され、高温ではあるが、適温に保たれて吸入通路３２の方へ送られる。この為、図２（ハ）の如くポペット弁２５の閉弁時期を遅らせて実圧縮比を１２程度としても（この時、ポペット弁２１の開弁時期も遅角し、実膨張比は１８．７位になる――これは冷却器２９の入口部の排ガス温度低下につながる）低圧縮比ながら圧縮端温度は十分に高く、噴射された燃料を良好に着火・燃焼させる事ができる。実圧縮比に対し実膨張比が１８．７位と高い為、熱効率向上幅が大となる。従来では実圧縮比に対し実膨張比を大とすると有効吸入行程減少の為に出力低下となるが、本発明では酸素噴射弁３８から噴射される酸素量を増量し、それに見合った燃料を噴射すれば良いので、出力低下はない。本発明ではポペット弁２５の閉時でシリンダー内に多量の既燃ガスが閉じ込められ、従来の様に吸入行程で冷たい空気を吸入する事もないので、低圧縮比ながら圧縮端温度は十分に高まり、エンジンアイドル状態でも低負荷域でも良好な燃焼を行なわせる事ができる。
燃料の燃焼に必要なものは酸素だけであるから、その必要分を――多少過剰気味とするが――噴射すれば良い。エンジン冷態時ではポペット弁２５の開閉時期を図２（イ）の状態としても良いが、図２（ニ）の如く進めて（早めて）実圧縮比を１８程度（この時、実膨張比は１３．２位となる――これは排ガス温度上昇につながる）とすると、それだけ排ガス温度や圧縮端温度が高まり、エンジン暖機運転期間が短縮する（排ガス浄化用触媒コンバーター付のものではそれだけ早く活性化温度に達する）。エンジン冷態時でも負荷が増大すれば、ポペット弁２５の開閉時期を遅らせて実圧縮比を下げる様に制御する事は言うまでもない。尚、図２において実圧縮比を可変化する為に、ポペット弁２５（吸気用）の下死点後の閉弁時期を変化させていたが、下死点前の閉弁時期を変化させても良く、同じ効果が得られる。
例えば図２（イ）においてはポペット弁２５の閉弁時期を下死点後６２℃Ａとして、実圧縮比を１６としていたが、図３の如く下死点前６２℃Ａとしても同じ実圧縮比１６が得られれる。図２（ロ）、（ハ）、（ニ）の場合も同様である。これは図１（イ）のバルブタイミング可変装置４では困難であるが、後に述べる立体カムを用いてこれを軸方向にスライドさせたり、図５の電磁式可変動弁装置を用いれば容易に実施できる。この方式によればポペット弁２５の開弁時期をも自由に設定できる（例えば開弁時期をほぼ一定とするる）利点がある。ポペット弁２１（排気用）についても同様とする事ができる。FIG. 2 is a graph showing changes in the opening / closing timing of the poppet valves 25 and 21 (indicated by the crank angle). Since the poppet valve 25 is for intake and the poppet valve 21 is for exhaust and is a four-cycle engine, Since the opening / closing operation is repeated once every two rotations and driven by the same variable valve timing device 4, the phase changes are the same. In the engine idle state, the poppet valve 25 (for intake) is opened at 10 ° C. A before top dead center and closed at 62 ° C. after bottom dead center as shown in FIG. The compression ratio is about 16, and the poppet valve 21 (for exhaust) is opened at 62 ° C. A before bottom dead center and closed at 10 ° C. before top dead center, and the actual expansion ratio (expansion when the poppet valve 21 is opened). The ratio is about 16. On the other hand, the control valve 34 is controlled by the electric actuator 35 so that the control valve 34 is fully open or almost fully open, and the control valve 33 is fully closed or slightly opened. Accordingly, the exhaust gas discharged from the cylinder is sent to the suction passage 32 through the bypass passage 36 (all or little through the cooler 29), so that the poppet valve 25 is kept at a high temperature. And when the poppet valve 25 is closed, a large amount is trapped in the cylinder, so that the compression end temperature (the gas temperature in the combustion chamber 20 at the compression top dead center) is sufficiently increased with a low compression ratio. The fuel injected from the injection valve 37 can be ignited and burned well. In the engine low load region, the fuel injection amount increases, the exhaust gas temperature increases, the opening degree of the control valve 34 is small, and the opening degree of the control valve 33 is controlled to be large. Although the exhaust gas to be produced is at a high temperature, it is cooled by the cooler 29 and maintained at an appropriate temperature. Therefore, even when the closing timing of the poppet valve 25 is delayed as shown in FIG. The opening timing of the poppet valve 21 is also retarded, and the actual expansion ratio is 17.6). Although the compression ratio is low, the compression end temperature is sufficiently high, and the injected fuel can be ignited and burned well.
Since the actual expansion ratio is higher than the actual compression ratio, an improvement in thermal efficiency can be expected. In the middle / high load range of the engine, the fuel injection amount further increases and the exhaust gas becomes even hotter, but the control valve 34 is fully closed (or almost fully closed) and the control valve 33 is fully opened (or almost fully open). Therefore, it is sufficiently cooled by the cooler 29 and is sent to the suction passage 32 while being kept at an appropriate temperature although it is hot. Therefore, as shown in FIG. 2C, even if the closing timing of the poppet valve 25 is delayed and the actual compression ratio is about 12, the opening timing of the poppet valve 21 is also retarded and the actual expansion ratio is 18. 7th place (this leads to a decrease in exhaust gas temperature at the inlet of the cooler 29) Despite the low compression ratio, the compression end temperature is sufficiently high, and the injected fuel can be ignited and burned well. Since the actual expansion ratio is as high as 18.7 with respect to the actual compression ratio, the range of improvement in thermal efficiency becomes large. Conventionally, if the actual expansion ratio is increased with respect to the actual compression ratio, the output decreases due to a decrease in the effective intake stroke. However, in the present invention, the amount of oxygen injected from the oxygen injection valve 38 is increased, and fuel commensurate with that is injected. There is no decrease in output. In the present invention, when the poppet valve 25 is closed, a large amount of burned gas is trapped in the cylinder, and cold air is not sucked in the suction stroke as in the conventional case, so that the compression end temperature is sufficiently increased while the compression ratio is low. Good combustion can be performed even in an engine idle state or in a low load range.
Since all that is needed to burn the fuel is oxygen, it may be injected—although a little overkill—to inject it. When the engine is cold, the opening and closing timing of the poppet valve 25 may be set to the state shown in FIG. 2 (a), but the actual compression ratio is about 18 (at this time, the actual expansion ratio is advanced as shown in FIG. 2 (d)). Will be ranked 13.2-this will lead to a rise in exhaust gas temperature), and the exhaust gas temperature and compression end temperature will increase accordingly, and the engine warm-up operation period will be shortened (with the exhaust gas purification catalyst converter that much faster) Reach the activation temperature). It goes without saying that if the load increases even when the engine is cold, the poppet valve 25 is controlled to delay the opening and closing timing to lower the actual compression ratio. In FIG. 2, the valve closing timing after the bottom dead center of the poppet valve 25 (for intake) is changed to vary the actual compression ratio. However, the valve closing timing before the bottom dead center is changed. The same effect can be obtained.
For example, in FIG. 2 (a), the closing timing of the poppet valve 25 is set to 62 ° C. after bottom dead center and the actual compression ratio is set to 16, but the same actual compression is set to 62 ° C. before bottom dead center as shown in FIG. A ratio of 16 is obtained. The same applies to FIGS. 2B, 2C, and 2D. This is difficult with the variable valve timing device 4 of FIG. 1 (a), but it can be easily carried out by sliding it in the axial direction using a solid cam described later, or using the electromagnetic variable valve device of FIG. it can. This method has an advantage that the opening timing of the poppet valve 25 can be freely set (for example, the opening timing is made substantially constant). The same applies to the poppet valve 21 (for exhaust).

次に図４において本発明における各種実施例について説明する。先ず図４（１）はピストンを断熱構造としたもので、燃焼室２０の壁面４１をセラミックなどの熱伝導率の低い部材で形成し、空気層４２を介してピストン本体に接続させたもので、この構造により冷却損失が減少して熱効率が向上する。シリンダーヘッド側もポペット弁２１，２５をセラミックなどの熱伝導率の低い部材で作って断熱構造とする事が望ましい。但し、シリンダー内壁面は潤滑の為に断熱構造とはしない。この様な断熱構造とすると、従来ではシリンダー内充填空気量が減少して出力低下となるが、本発明では酸素噴射弁３８により強制的に必要量の酸素を噴射するので、出力低下はない。図４（ロ）はポペット弁２５（既燃ガスを吸入する図１と同じもの）とは別系統で空気をシリンダー内に吸入する空気導入弁４３を備えたもので、所定量（少量とする）の空気をシリンダー内に導入する事により酸素供給容器１５の小型化を図ったものである。４４はエァフローメーターで、エンジン回転速度によりシリンダー内に導入される空気量（酸素量）が知れるから、この分を差し引いて酸素噴射弁３８は酸素を噴射する。
図４（ハ）、（ニ）はポペット弁２５（吸気用）の役割をポペット弁２１（排気用）に持たせたものに相当する実施例を示し（図４（ハ）は図４（ニ）を上方から見てポペット弁４５、燃料噴射弁３７、酸素噴射弁３８等のレイアウトを示す図である）、ポペット弁４５は下死点前の所定のクランク角度で開いて既燃ガスを排出し、下死点から上死点に到る排気行程でも、更にはこの上死点から下死点へ到る吸気行程でも開き続け、下死点後の所定のクランク角度で閉じる様になっている（但し、上死点付近ではピストンとの干渉を避ける為、ポペット弁４５のリフト量は小さい――上死点付近でポペット弁４５を一旦閉じても良い）。ガス流通路２６′、２６″は図１の排出通路２６に相当し、各気筒毎に設けられ、冷却器２９′も各気筒毎に設けられている。
従ってシリンダー内から排出された排ガスはガス流通路２６′を通って冷却器２９′に到り、ここで冷却された後にガス流通路２６″を通ってサージタンク２７′（各気筒に共通）に到るが、この排ガスは吸気行程中の気筒があればその気筒のガス流通路２６″、冷却器２９′、ガス流通路２６′を通ってその気筒のシリンダー内に十分に冷却されて吸入される事になる。
燃料噴射弁３７からの燃料噴射及び酸素噴射弁３８からの酸素噴射は図１と同様に行なわれる。冷却器２９′により冷却されてシリンダー内に吸入されると言っても、冷たい空気を吸入するよりは温度が高いから、低圧縮比ながら良好な燃焼が得られる。図４（ニ）の場合、図４（ホ）の様にガス流通路２６′と２６″とをバイパスするバイパス通路３６′を設け、制御弁３９′（各気筒毎に設ける）により冷却器２９′を通る排ガス量とバイパス通路３６′を通る排ガス量とを調整すれば、エンジン負荷に応じてシリンダー内に吸入されるガス温度を制御できるから、図４（ニ）よりは一層良好な燃焼を得る事ができる。尚、図４（ハ）、（ニ）、（ホ）に示す実施例では図４（ロ）と同様に空気導入弁４３を備えて、酸素供給容器１５の小型化を図っても良い。Next, various embodiments of the present invention will be described with reference to FIG. First, FIG. 4 (1) shows a piston with a heat insulating structure, in which the wall surface 41 of the combustion chamber 20 is formed of a member having a low thermal conductivity such as ceramic and connected to the piston body via an air layer 42. This structure reduces the cooling loss and improves the thermal efficiency. On the cylinder head side, it is desirable that the poppet valves 21 and 25 are made of a material having low thermal conductivity such as ceramic to have a heat insulating structure. However, the inner wall of the cylinder is not heat-insulated for lubrication. With such a heat insulating structure, conventionally, the amount of air charged in the cylinder decreases and the output decreases. However, in the present invention, the oxygen injection valve 38 forcibly injects the required amount of oxygen, so there is no decrease in output. FIG. 4 (b) is a system different from the poppet valve 25 (same as FIG. 1 for sucking burned gas) and is provided with an air introduction valve 43 for sucking air into the cylinder. ) Is introduced into the cylinder to reduce the size of the oxygen supply container 15. 44 is an air flow meter, and since the amount of air (oxygen amount) introduced into the cylinder is known by the engine speed, the oxygen injection valve 38 injects oxygen by subtracting this amount.
4 (c) and 4 (d) show an embodiment corresponding to the poppet valve 21 (for exhaust) having the role of the poppet valve 25 (for intake) (FIG. 4 (c) is similar to FIG. 4 (d). ) Is a view showing the layout of the poppet valve 45, the fuel injection valve 37, the oxygen injection valve 38, etc.) from above, and the poppet valve 45 opens at a predetermined crank angle before bottom dead center and discharges burned gas. In the exhaust stroke from the bottom dead center to the top dead center, and in the intake stroke from the top dead center to the bottom dead center, the valve opens continuously and closes at a predetermined crank angle after the bottom dead center. (However, in order to avoid interference with the piston near the top dead center, the poppet valve 45 lift is small—the poppet valve 45 may be closed once near the top dead center). The gas flow passages 26 'and 26 "correspond to the discharge passage 26 of FIG. 1, and are provided for each cylinder, and a cooler 29' is also provided for each cylinder.
Accordingly, the exhaust gas discharged from the cylinder reaches the cooler 29 'through the gas flow passage 26', and after being cooled there, passes through the gas flow passage 26 "to the surge tank 27 '(common to each cylinder). However, if there is a cylinder in the intake stroke, the exhaust gas is sufficiently cooled and sucked into the cylinder of the cylinder through the gas flow passage 26 ″, the cooler 29 ′, and the gas flow passage 26 ′ of the cylinder. It will be.
Fuel injection from the fuel injection valve 37 and oxygen injection from the oxygen injection valve 38 are performed in the same manner as in FIG. Even if it is cooled by the cooler 29 'and sucked into the cylinder, the temperature is higher than that of sucking cold air, so that good combustion can be obtained with a low compression ratio. In the case of FIG. 4 (d), as shown in FIG. 4 (e), a bypass passage 36 'for bypassing the gas flow passages 26' and 26 "is provided, and a cooler 29 is provided by a control valve 39 '(provided for each cylinder). By adjusting the amount of exhaust gas passing through ′ and the amount of exhaust gas passing through the bypass passage 36 ′, the gas temperature sucked into the cylinder can be controlled according to the engine load. Therefore, better combustion than in FIG. 4 (C), (D), and (E), the air supply valve 43 is provided in the same manner as in FIG. May be.

ところで本発明ではポペット弁２１，２５，（４５）の開弁時期や閉弁時期を変化させて実圧縮比や実膨張比を可変化しているが、図１に示したものの他に多くの公知の可変動弁装置を用いる事ができる。例えば特開平８−１７７４３４号公報にはヘリカルスプラインを軸方向に移動させてカム位相角を変えるものが開示され、電磁式又は電動式にカム位相角を変えるものが特開２００１−１６４９５１号公報、特開２００３−２７８５１４号公報、特開２００７−１００６８１号公報に開示されている。これらはいずれも図１と同様に開弁期間は変えずにポペット弁２１，２５，（４５）の開閉時期を変えるものである。更には立体カム（通常の平面カムを多段に並べたものも含む）を用い、これを油圧式又は電磁式アクチュエーターによりＥＣＵ１４からの制御信号によって軸方向にスライドさせ、位置制御する方法も考えられる（公知の技術である）。図５は電磁式可変動弁装置を示すもので、ハウジング４６にはリング状に形成された電磁石４８，４９がポペット弁２５（２１）の弁軸と一体となったプランジャー４７を挟んで対向した状態で配置されている。電磁石４８，４９の各々の中空部にはバネ５０，５１がプランジャー４７を挟む様に取り付けられ、この為、ポペット弁２５（２１）はバネ５０，５１の力の釣り合いにより弁リフトの中間位置に静止する、電磁石４８が磁励されるとプランジャー４７が上方へ引き付けられ、ポペット弁２５（２１）は閉弁し、電磁石４９が磁励されるとプランジャー４７が下方へ引き付けられ、開弁する。ドライバー５２はポペット弁２５（２１）の開閉時期を指定するＥＣＵ１４からの制御信号に応じて電磁石４８，４９に交互に励磁電流を供給する。これによりポペット弁２５（２１）はＥＣＵ１４が指示した時期に開閉駆動される。これによるとポペット弁２１，２５の開弁時期や閉弁時期を互いに独立的に設定できるから、自由度が増す。例えば、実膨張比を同一としたまま実圧縮比のみを変えるなどである。何よりも応答遅れがないのが大きな特長である。 By the way, in the present invention, the actual compression ratio and the actual expansion ratio are made variable by changing the valve opening timing and the valve closing timing of the poppet valves 21, 25 (45). A known variable valve operating device can be used. For example, Japanese Patent Application Laid-Open No. 8-177434 discloses a device that changes a cam phase angle by moving a helical spline in the axial direction, and a device that changes the cam phase angle electromagnetically or electrically is disclosed in Japanese Patent Application Laid-Open No. 2001-164951, It is disclosed in Japanese Patent Application Laid-Open Nos. 2003-278514 and 2007-1000068. In either case, the opening / closing timing of the poppet valves 21, 25, (45) is changed without changing the valve opening period as in FIG. Furthermore, a method of controlling the position by using a three-dimensional cam (including a normal flat cam arranged in multiple stages) and sliding it in the axial direction by a control signal from the ECU 14 by a hydraulic or electromagnetic actuator is also conceivable (see FIG. This is a known technique). FIG. 5 shows an electromagnetic variable valve operating apparatus. Electromagnets 48 and 49 formed in a ring shape are opposed to the housing 46 with a plunger 47 integrated with the valve shaft of the poppet valve 25 (21) interposed therebetween. It is arranged in the state. The springs 50 and 51 are attached to the hollow portions of the electromagnets 48 and 49 so that the plunger 47 is sandwiched between them. Therefore, the poppet valve 25 (21) is positioned at an intermediate position of the valve lift by the balance of the forces of the springs 50 and 51. When the electromagnet 48 is magnetized, the plunger 47 is attracted upward, the poppet valve 25 (21) is closed, and when the electromagnet 49 is magnetized, the plunger 47 is attracted downward and opened. I speak. The driver 52 alternately supplies an excitation current to the electromagnets 48 and 49 in accordance with a control signal from the ECU 14 that designates the opening / closing timing of the poppet valve 25 (21). As a result, the poppet valve 25 (21) is driven to open and close at a time designated by the ECU 14. According to this, since the opening timing and closing timing of the poppet valves 21 and 25 can be set independently of each other, the degree of freedom increases. For example, only the actual compression ratio is changed while keeping the actual expansion ratio the same. The biggest feature is that there is no response delay.

次に本発明ではポペット弁２１の開弁時期を固定したままポペット弁２５の閉弁時期を変え、即ち実膨張比を固定したまま実圧縮比のみを可変化しても良く、これは既に述べた立体カムを用いたり、図５の電磁式可動弁装置を用いる事により可能である。しかしながら本発明ではポペット弁２１，２５の開弁時期や閉弁時期を互いに独立的に設定する事がより望ましい（図１ではポペット弁２５の閉弁時期により実圧縮比を設定すると、ポペット弁２１の開弁時期が一義的に定まり、実膨張比も一義的に定まる）。
これも立体カムや図５の電磁式可変動弁装置により可能となるが、バルブタイミング可変装置（例えば図１のもの）を用いた実施例を図６に示す。即ち図６において図１のポペット弁２１はカム軸２２Ａで、駆動され、図１のポペット弁２５はカム軸２２Ｂで、駆動され、ポペット弁２１，２５はバルブタイミング可変装置４Ａ，４Ｂにより各々の開閉時期を互いに独立的に設定できる様に構成され、これにより実圧縮比、実膨張比を互いに独立的に設定する事ができ、自由度が増す。例えば実膨張比を固定したまま実圧縮比のみを変える、図２（イ）で実膨張比を１７にするなどである。１０Ａ，１０Ｂは各々のバルブタイミング可変装置４Ａ，４Ｂに油圧を供給する油圧制御弁で、ＥＣＵ１４からの制御信号により駆動される。Next, in the present invention, the closing timing of the poppet valve 25 may be changed while the opening timing of the poppet valve 21 is fixed, that is, only the actual compression ratio may be varied while the actual expansion ratio is fixed. This is possible by using a solid cam or by using the electromagnetic movable valve device shown in FIG. However, in the present invention, it is more desirable to set the opening timing and closing timing of the poppet valves 21 and 25 independently of each other (in FIG. 1, when the actual compression ratio is set by the closing timing of the poppet valve 25, the poppet valve 21 The valve opening timing is uniquely determined, and the actual expansion ratio is also uniquely determined).
This can also be achieved by the three-dimensional cam or the electromagnetic variable valve actuating device shown in FIG. 5, but FIG. That is, in FIG. 6, the poppet valve 21 in FIG. 1 is driven by the cam shaft 22A, the poppet valve 25 in FIG. 1 is driven by the cam shaft 22B, and the poppet valves 21 and 25 are respectively driven by the valve timing variable devices 4A and 4B. The open / close timing can be set independently of each other, whereby the actual compression ratio and the actual expansion ratio can be set independently of each other, and the degree of freedom is increased. For example, only the actual compression ratio is changed while the actual expansion ratio is fixed, or the actual expansion ratio is set to 17 in FIG. 10A and 10B are hydraulic control valves that supply hydraulic pressures to the variable valve timing devices 4A and 4B, and are driven by control signals from the ECU 14.

本発明は酸素噴射式４サイクル内燃機関であり、図１ではディーゼル機関として説明したが、次に図７において火花点火機関としての説明をする。即ち、図７（イ）の１断面を図７（ロ）に、図７（ロ）を上方から見て図７（ハ）にポペット弁２１，２５，燃料噴射弁３７，酸素噴射弁３８，点火プラグ５３などのレイアウトを示す。図７（イ）は図１（イ）と同一、図７（ロ）は図１（ロ）と同一で、図７と図１との違いは点火プラグ５３の有無である（細かく言えば燃料噴射弁３７の噴射時期（圧縮上死点よりかなり早い時期に噴射、更には吸気行程中に噴射など）や取り付け位置（吸入通路３２に取り付けても良い）、燃焼室２０の形状などに違いはあるが）。本発明ではポペット弁２５が閉弁した時点でシリンダー内に多量の既燃ガスが内部ＥＧＲとして閉じ込められる為、図７ではエンジンアイドル状態を含む低負荷域では点火プラグ５３による点火・燃焼が困難である。これに対処するには超希薄混合気でも点火・燃焼可能な水素を燃料とする事が考えられる（水素であれば空気過剰率１０でも点火可能である）。但し、燃焼速度が遅い為、熱効率上は問題があるので、酸素噴射弁３８から酸素をかなり過剰に噴射して燃焼を活発化させ、燃焼速度を増す様に工夫する。幸いな事に本発明ではシリンダー内から排出される排ガスは冷却器２９により十分に冷却された後にポペット弁２５を介してシリンダー内に吸入される為、排ガスの体積縮小が起り、シリンダー内から排出される排ガスの殆どをシリンダー内に再吸入する事ができる（この観点からは制御弁３３，３４，バイパス通路３６は不要である）。従って、前述の様にかなり過剰の酸素を噴射しても、その殆どをシリンダー内に再吸入して回収する事ができ、酸素消費量は殆ど増えない特長がある（これは図１でも同一であり、かなり過剰の酸素を噴射して、ＰＭの発生をなくす事ができる）。更に燃焼速度を増す手段として実圧縮比を高くする、スキッシュを強化するなどの手法がある。
図７に示す本発明では水素以外の燃料、例えばガソリンの様なものでは点火プラグ５３による点火・燃焼が困難であるから、この様な場合は燃料を早期に噴射して予め混合気として形成しておき、ピストンの上昇行程によって圧縮して圧縮（自己）着火させる予混合圧縮着火燃焼法を用いる事が望ましい（過剰の酸素を噴射する必要もなくなる）。本発明では次の理由によりこの予混合圧縮着火燃焼の領域を大幅に拡大する事ができる。即ち、本発明ではポペット弁２５の閉時に多量の高温既燃ガスが内部ＥＧＲとして閉じ込められること、従来の様に冷たい空気を吸入しない事によるシリンダー内ガス冷却がないこと、更には実圧縮比を自在に可変化（必要なだけ高める）できることなどから、圧縮端温度を大幅に高め、燃料の自己着火温度（ガソリンの場合では約１０００°Ｋ）に到達させる事ができる。この為、エンジンアイドル時や低負荷域ではポペット弁２５，２１の開閉時期を図２（イ）、（ロ）の如く制御して実圧縮比を高めると共に（数値そのものは異なるが）、制御弁３４を全開（又はほぼ全開）、制御弁３３を全閉（又は若干開く）として、吸入通路３２からシリンダー内へ吸入される既燃ガスを（殆ど）冷却しない様にし、圧縮端温度を十分に高められるから、予混合圧縮着火燃焼を行なわせる事ができる。
燃料によってはエンジンアイドル状態では予混合圧縮着火燃焼が起らない事もあるから、この場合は図２（ニ）の如く実膨張比を低く（排ガス温度が高まり、シリンダー内に吸入される既燃ガスの温度が高まる）、実圧縮比を高くして対処する、エンジン中負荷域や高負荷域ではポペット弁２５，２１の開閉時期を図２（ハ）の如く制御して実膨張比を高め（排気ガス温度が低下してシリンダー内に吸入される既燃ガスの温度が低下する）、実圧縮比を低くするので（１０又はそれ以下、例えば７位に下げても良い――実膨張比の方は却って高まる）、圧縮端温度は適正に保たれ、従来では発生したノックを回避する事ができる。
エンジン低・中・高負荷域でも回転速度が高い程、燃料の自己着火の発現が相対的に遅れるから、ポペット弁２５，２１の開閉時期を制御して実圧縮比を高める様にする。制御弁３４はエンジン負荷の増大に従って閉じる様に制御し（制御弁３３は逆に開く様に制御）、高負荷域では全閉とする（制御弁３３は全開）。エンジンの始動及び暖機がある程度進むまでは通常の火花点火燃焼とし、暖機がある程度進んだらポペット弁２５，２１の開閉時期を図２（ニ）の如く制御して、実膨張比を下げ（排ガス温度が高まる）、実圧縮比を高めるので、圧縮端温度は十分に高められ、予混合圧縮着火燃焼を行なわせる事ができる（もちろん制御弁３４は全開、制御弁３３は全閉とする）。前述の如くエンジンの始動及びある程度進むまでは通常の火花点火燃焼とするが、この場合、かなり過剰の酸素を噴射して燃焼を活発化させる手法も講ずると良い。エンジンの暖機が完了したらポペット弁２５，２１の開閉時期は図２（イ）、（ロ）、（ハ）の状態に戻す。
この様に本発明では圧縮端温度を自在に制御できるから、予混合圧縮着火燃焼の運転領域を大幅に拡大できるが、高負荷域ではノックの発生から限界がある。そこでこの場合は、通常の点火プラグ５３による火花点火燃焼に切り換える（この時は燃焼条件も良好なので、点火プラグによる点火・燃焼に何ら問題はない）。ＥＣＵ１４はエンジン負荷、回転速度などの運転条件により図８を参照して予混合圧縮着火燃焼と火花点火燃焼とを切り換える様にしている。以上の予混合圧縮着火燃焼は図１の場合にも所定の運転領域において行なわせる事ができる（同様にエンジン負荷、回転速度などの運転条件により燃焼方式を切り換える）。尚、図７に示す本発明では図５，６，４で説明した各実施例を適用できる事は言うまでもない。The present invention is an oxygen injection type four-cycle internal combustion engine, which has been described as a diesel engine in FIG. 1, but will be described as a spark ignition engine in FIG. That is, one section of FIG. 7 (a) is shown in FIG. 7 (b), FIG. 7 (b) is viewed from above, and FIG. 7 (c) is a poppet valve 21, 25, fuel injection valve 37, oxygen injection valve 38, The layout of the spark plug 53 etc. is shown. FIG. 7 (a) is the same as FIG. 1 (a), FIG. 7 (b) is the same as FIG. 1 (b), and the difference between FIG. 7 and FIG. There are differences in the injection timing of the injection valve 37 (injection at a time much earlier than the compression top dead center, injection in the intake stroke, etc.), the attachment position (may be attached to the intake passage 32), the shape of the combustion chamber 20, etc. There is.) In the present invention, when the poppet valve 25 is closed, a large amount of burned gas is confined as internal EGR in the cylinder. Therefore, in FIG. 7, ignition and combustion by the spark plug 53 is difficult in a low load region including the engine idle state. is there. In order to cope with this, it is conceivable to use hydrogen that can be ignited and combusted even in an ultra-lean mixture (if it is hydrogen, it can be ignited even with an excess air ratio of 10). However, since the combustion speed is slow, there is a problem in thermal efficiency, so that oxygen is considerably excessively injected from the oxygen injection valve 38 to increase the combustion speed so as to increase the combustion speed. Fortunately, in the present invention, the exhaust gas discharged from the cylinder is sufficiently cooled by the cooler 29 and then sucked into the cylinder through the poppet valve 25, so that the volume of the exhaust gas is reduced and discharged from the cylinder. Most of the exhaust gas to be discharged can be re-inhaled into the cylinder (the control valves 33 and 34 and the bypass passage 36 are unnecessary from this viewpoint). Therefore, even if a large excess of oxygen is injected as described above, most of the oxygen can be re-inhaled into the cylinder and recovered, and the oxygen consumption is hardly increased (this is the same as in FIG. 1). Yes, it is possible to eliminate the generation of PM by injecting a considerable excess of oxygen). Further, as means for increasing the combustion speed, there are techniques such as increasing the actual compression ratio and strengthening the squish.
In the present invention shown in FIG. 7, it is difficult to ignite and burn with a spark plug 53 in a fuel other than hydrogen, such as gasoline, so in such a case, fuel is injected early to form an air-fuel mixture in advance. In addition, it is desirable to use a premixed compression ignition combustion method in which compression is performed by the upward stroke of the piston and compression (self) ignition is performed (there is no need to inject excess oxygen). In the present invention, the premixed compression ignition combustion region can be greatly expanded for the following reason. That is, in the present invention, when the poppet valve 25 is closed, a large amount of high temperature burned gas is confined as internal EGR, there is no gas cooling in the cylinder by not sucking cold air as in the prior art, and further, the actual compression ratio is increased. Since it can be freely varied (increased as much as necessary), the compression end temperature can be significantly increased, and the fuel self-ignition temperature (about 1000 ° K. in the case of gasoline) can be reached. For this reason, at the time of engine idling or in a low load region, the opening and closing timing of the poppet valves 25 and 21 is controlled as shown in FIGS. 2 (a) and 2 (b) to increase the actual compression ratio (although the numerical value itself is different), 34 is fully opened (or almost fully opened) and the control valve 33 is fully closed (or slightly opened) so that the burned gas sucked into the cylinder from the suction passage 32 is not cooled, and the compression end temperature is sufficiently increased. Therefore, premixed compression ignition combustion can be performed.
Depending on the fuel, premixed compression ignition combustion may not occur in the engine idle state. In this case, the actual expansion ratio is low as shown in FIG. (The temperature of the gas is increased), and the actual compression ratio is increased. In the middle load range and high load range of the engine, the poppet valves 25 and 21 are controlled to open and close as shown in FIG. (The exhaust gas temperature decreases and the temperature of the burned gas sucked into the cylinder decreases.) Since the actual compression ratio is lowered (10 or less, for example, it may be lowered to 7th place-the actual expansion ratio) On the other hand, the compression end temperature is maintained properly, and knocks that have conventionally occurred can be avoided.
Since the self-ignition of the fuel is relatively delayed as the rotational speed increases even in the engine low, medium and high load regions, the actual compression ratio is increased by controlling the opening and closing timing of the poppet valves 25 and 21. The control valve 34 is controlled to close as the engine load increases (the control valve 33 is controlled to open in reverse), and is fully closed in the high load range (the control valve 33 is fully opened). Until the engine starts and warms up to some extent, normal spark ignition combustion is performed. When the warmup progresses to some extent, the opening / closing timing of the poppet valves 25 and 21 is controlled as shown in FIG. Since the exhaust gas temperature is increased), the actual compression ratio is increased, so that the compression end temperature is sufficiently increased and premixed compression ignition combustion can be performed (of course, the control valve 34 is fully opened and the control valve 33 is fully closed). . As described above, normal spark ignition combustion is performed until the engine starts and progresses to some extent, but in this case, it is preferable to take a method of injecting a considerably excessive oxygen to activate combustion. When engine warm-up is completed, the opening and closing timing of the poppet valves 25 and 21 is returned to the states shown in FIGS. 2 (a), (b) and (c).
As described above, the compression end temperature can be freely controlled in the present invention, so that the operation range of the premixed compression ignition combustion can be greatly expanded. However, there is a limit in the high load range from the occurrence of knock. Therefore, in this case, switching to the spark ignition combustion by the normal spark plug 53 is performed (the combustion conditions are good at this time, so there is no problem with the ignition / combustion by the spark plug). The ECU 14 switches between premixed compression ignition combustion and spark ignition combustion with reference to FIG. 8 according to operating conditions such as engine load and rotation speed. The above premixed compression ignition combustion can be performed in a predetermined operation region also in the case of FIG. 1 (similarly, the combustion method is switched depending on the operation conditions such as the engine load and the rotational speed). In the present invention shown in FIG. 7, it goes without saying that the embodiments described with reference to FIGS.

ところで図７においてＥＣＵ１４はエンジン負荷、回転速度、冷却水温等のパラメーターによりバルブタイミング可変装置４が最適制御される様に油圧制御弁１０に制御信号を出力するが、エンジンの急激な過渡期においてはバルブタイミング可変装置４の制御が遅れ、即ち実圧縮比や実膨張比の制御が遅れ、予混合圧縮着火燃焼の領域において失火や燃焼未完結、更にはノックを生じる事がある。図９はこれらの不具合を未然に防ぐ為の制御ルーチンを示す。先ずステップＳ_１では予混合圧縮着火燃焼を行なわせる運転領域か否かを判定する。これはエンジン負荷、回転速度等の運転状態を検出するパラメーターに基づき図８を参照して決定する。そして予混合圧縮着火燃焼を行なわせる運転領域であれば（ＹＥＳ）ステップＳ_２へ進み、現在のカム軸２２のカム位相角をを検出する。続いてステップＳ_３に進み、この現在のカム位相角が制御上の目標値との位相差において所定値以上に遅角しているか否かを判別する。そして所定値以上に遅角していれば（ＹＥＳ）ステップＳ_４に進み、失火を含む不安定燃焼回避手段として、例えば酸素噴射弁３８からの酸素噴射量を通常より増量させてルーチンを抜ける。通常より増量させて酸素噴射を行なう事により燃料と酸素との酸化反応が活発化し、予混合圧縮着火燃焼における失火や燃焼未完結を未然に防ぐ事ができる。この他の不安定燃焼回避手段としては、制御弁３４の開度を瞬時に大とし、制御弁３３の開度を瞬時に小とする方法がある（制御弁３４，３３の全閉から全開までの作動角が小さくなる様に取り付け状態を工夫すれば――全閉状態の取り付けを排ガスの流れの方向にできる限り寝かせる様に取り付ける――瞬時にその開度を大とし、又は小とする事ができる）。こうするとシリンダー内へ吸入される既燃ガスの温度が高まるので、同様の効果がある。ステップＳ_３で判定が不成立（ＮＯ）の場合はステップＳ_５に進み、ステップＳ_２で検出した現在のカム位相角が制御上の目標値との位相差において所定値以上に進角しているか否かを判別する。所定値以上に進角していなければ（ＮＯ）、ここでルーチンを抜ける。そして所定値以上に進角していれば（ＹＥＳ）ステップＳ_６へ進み、ノック回避手段として例えば燃料噴射弁３７の燃料噴射時期を遅角させてルーチンを抜ける。圧縮行程中の燃料噴射時期を遅角すると燃料の着火時期を遅らせる事ができ、燃料室内圧力ピーク位置も遅角して圧力ピークが下がり、ノックの発生を回避する事ができる。この場合、燃料噴射を２回に分けて噴射しても良い。ノック回避手段としては酸素噴射弁３８の酸素噴射時期を遅角する事も考えられ（もちろん燃料の方を先に噴射する）、これにより燃料の着火時期を遅らせ、ノックを回避する事ができる。In FIG. 7, the ECU 14 outputs a control signal to the hydraulic control valve 10 so that the valve timing variable device 4 is optimally controlled by parameters such as engine load, rotation speed, and cooling water temperature. Control of the valve timing variable device 4 is delayed, that is, control of the actual compression ratio and actual expansion ratio is delayed, and misfire, incomplete combustion, and knocking may occur in the premixed compression ignition combustion region. FIG. 9 shows a control routine for preventing these problems. Determines whether the operation region where first to perform step S ₁ in homogeneous charge compression ignition combustion. This is determined with reference to FIG. 8 on the basis of parameters for detecting operating conditions such as engine load and rotational speed. And, if the operating area to perform the HCCI combustion process proceeds to (YES) Step S _2, it detects a cam phase angle for the current camshaft 22. Then the process proceeds to step S _3, the current cam phase angle is determined whether or not retarded than the predetermined value in the phase difference between the target value of the control. And if the retarded than the predetermined value, the process proceeds to (YES) Step S _4, the combustion instability avoiding means including misfire, exits the routine, for example, the oxygen injection amount from the oxygen injector 38 is increased than usual. By performing oxygen injection with the amount increased than usual, the oxidation reaction between fuel and oxygen is activated, and misfires and incomplete combustion in premixed compression ignition combustion can be prevented. As another unstable combustion avoiding means, there is a method in which the opening degree of the control valve 34 is instantaneously increased and the opening degree of the control valve 33 is instantaneously reduced (from fully closed to fully opened control valves 34 and 33). If the installation state is devised so that the operating angle of the valve becomes smaller-Install the fully closed installation so that it lays down as much as possible in the direction of exhaust gas flow-Instantaneously increase or decrease its opening Can do). This increases the temperature of the burned gas that is sucked into the cylinder, and has the same effect. If the determination in step S ₃ is not satisfied (NO) the process proceeds to step S _5, whether the current cam phase angle detected in step S ₂ is advanced to a predetermined value or more in the phase difference between the target value for control Determine whether or not. If the advance is not greater than the predetermined value (NO), the routine is exited. And if the advanced more than a predetermined value, the process proceeds to (YES) step S _6, exits the routine was retarded fuel injection timing, for example, the fuel injection valve 37 as a knock avoidance means. If the fuel injection timing during the compression stroke is retarded, the fuel ignition timing can be retarded, the pressure peak position in the fuel chamber is also retarded, the pressure peak is lowered, and knocking can be avoided. In this case, the fuel injection may be divided into two. As a knock avoiding means, it is conceivable to delay the oxygen injection timing of the oxygen injection valve 38 (of course, the fuel is injected first), so that the ignition timing of the fuel can be delayed and the knock can be avoided.

本発明における酸素供給容器１５には予め３５０気圧程度に圧縮した高圧酸素を充填させておくのが一般的であるが、図１０の如く酸素濃度富化装置５４により空気中の酸素を濃化して圧縮機５６により圧縮し、これを酸素供給容器１５へ送り込む様にしても良い（５〜１０気圧程度の圧力で良い）。この場合、できる限り酸素濃度を高めて窒素含有率を少なくする事が必要である。酸素濃度富化装置５４は酸素透過膜５５（例えばシリコン柔ゴム膜、ポリブタジエンなどを材質とする）を有し、圧力差を与えて酸素と窒素との溶解速度の差により酸素を多く透過させるものである。この他、合成ゼオライトに窒素を吸着させる窒素吸着法による酸素濃度富化装置も考えられる。
尚、本発明では酸素噴射弁３８の噴射時期をポペット弁２１の閉弁前とし、酸素噴射により若干のシリンダーが掃気を行っても良い。The oxygen supply container 15 according to the present invention is generally filled with high-pressure oxygen that has been compressed to about 350 atm in advance, but oxygen in the air is concentrated by an oxygen concentration enrichment device 54 as shown in FIG. You may make it compress with the compressor 56 and send this to the oxygen supply container 15 (the pressure of about 5-10 atmospheres may be sufficient). In this case, it is necessary to increase the oxygen concentration as much as possible to reduce the nitrogen content. The oxygen concentration enrichment device 54 has an oxygen permeable membrane 55 (for example, made of silicon soft rubber membrane, polybutadiene, etc.), which gives a pressure difference and allows a large amount of oxygen to permeate due to a difference in dissolution rate between oxygen and nitrogen. It is. In addition, an oxygen concentration enrichment apparatus using a nitrogen adsorption method in which nitrogen is adsorbed on a synthetic zeolite is also conceivable.
In the present invention, the injection timing of the oxygen injection valve 38 may be set before the poppet valve 21 is closed, and some cylinders may scavenge by oxygen injection.

The invention's effect

本発明では空気を作動流体として使っていない為、ＮＯｘの発生は根源から断ち切られ、排出は０である。もちろん図４（ロ）の如く少量の空気を導入して酸素供給容器１５の小型化を図る場合もあるが、常に多量の内部ＥＧＲが為されている為、ＮＯｘの発生は殆ど０である。又、本発明ではポペット弁２５の閉弁時に多量の高温既燃ガスが内部ＥＧＲとして閉じ込められること、従来の様に冷たい空気を吸入しないことによるシリンダー内ガス冷却がないこと、更には実圧縮比を自在に可変化（必要なだけ高める）できることなどから、圧縮端温度を大幅に高める事ができる為、エンジンアイドル状態を含む低負荷域でも予混合圧縮着火燃焼を行なわせる事ができる（自己着火温度が高い燃料を使用する場合は、この領域でも図２（ニ）の如く実膨張比を低くし、実圧縮比を高くして、圧縮端温度を更に高める手法も可能である）。エンジン高負荷域では制御弁３４，３３を制御して冷却器２９により排ガスを十分に冷却してシリンダー内に吸入させ、かつ実圧縮比も低く制御するので（実膨張比は高くなり、これは排ガス温度の低下につながる）、ノックの発生を回避し、かくして予混合圧縮着火燃焼の運転領域を大幅に拡大する事ができる。この予混合圧縮着火燃焼法は燃焼室内の各部が一斉に燃焼を開始し、燃焼室内ガス温度勾配がない急速低温燃焼であり、超希薄混合気でも確実に燃焼させる事ができる燃焼法である。従って、スロットル弁により吸気を絞って制御する必要がないから、従来の火花点火燃焼法の様なポンプ損失がなく、かつ燃焼最高温度が低く抑える事ができるから、冷却損失が少なく、以上の理由により熱効率の大幅改善が可能である。更に従来では実圧縮比に対し実膨張比を大として高膨張比化すると、有効吸入行程の減少により出力低下となるが、本発明によれば有効吸入行程の減少に拘らず酸素噴射量とこれに見合った燃料とを増量して噴射すれば良いから、出力低下はなく、思い切り高膨張比化して熱効率を更に向上させる事ができる。加えて、従来ではピストン、シリンダーヘッドなどを断熱構造とすると吸入空気量の減少により出力低下を招くが、本発明では酸素噴射量とこれに見合った燃料を増量して噴射すれば良いから、出力低下はなく（酸素噴射量を増量して酸素濃度を増しても、多量の内部ＥＧＲによりノックは発生しない）、冷却損失の低域が可能である。又、ディーゼル機関としての本発明では多量の内部ＥＧＲにより圧縮端温度を高める事ができるから、低圧縮比化により摩擦損失を減らす事ができ、以上から熱効率の飛躍的な改善が可能である。次に本発明の大きな特長として、シリンダー内から排出される既燃ガスを冷却器２９により十分に冷却した後にシリンダー内に再吸入させるから、排ガスの体積縮小が起り、シリンダー内から排出される既燃ガスの殆どをシリンダー内に再吸入させる事ができる点が挙げられる。従って排ガス中の有害成分であるＨＣ，ＣＯ，更にはディーゼル機関ではＰＭもあるが、これらを殆ど再吸入して再燃焼させる事ができるから、大気中に放出される有害成分は殆ど０で、これらを浄化させるべき触媒コンバーターを不要とする事ができる。更にはシリンダー内から排出される排ガスを殆どシリンダー内に再吸入できるから、過剰の酸素を噴射してもその殆どを回収する事ができ、シリンダー内酸素量を思い切り高めて酸素高過剰燃焼させても酸素消費量は増加しない。
この為、ディーゼル機関としての本発明ではＰＭの発生は燃焼過程でも殆どなく、火花点火機関としての本発明でもエンジンアイドル状態を含む低負荷域では内部ＥＧＲが為されているにも拘らず燃焼が活発化し、点火プラグによる点火・燃焼が良好に行なわれる（燃焼速度が大で、不整燃焼も発生しない）。この場合、酸素高過剰燃焼を行なわせるには、常時多量の酸素を噴射し続ける必要はなく、最初のサイクルで多量の酸素を噴射して酸素高過剰燃焼を行なわせ、次のサイクルからは燃料の燃焼に必要な分を（多少過剰気味とはするが）噴射すれば良いのである。水素は超希薄混合気でも点火プラグによる火花点火燃焼が可能であるが、燃焼速度が小さくなる欠点がある。しかし、本発明によれば前述の如く酸素高過剰燃焼させても酸素消費量が増加しない為、エンジンアイドル状態を含む低負荷域でこの酸素高過剰燃焼を行なわせる事により点火プラグによる点火・着火性が良好な燃焼速度の大きな燃焼を行なわせる事ができ（予混合圧縮着火燃焼に頼る事なく通常の火花点火燃焼により可能である）、ポンプ損失がない事と合わせて熱効率の大幅改善が可能である。シリンダー内から排出される排ガスを冷却器２９により１００℃以下に冷却すれば水分の凝縮が起るから、全部回収可能とは言わないまでもほぼ１００％回収可能であり、事実上、排ガス量は０である。更に水素を酸素と同様に高圧の水素供給容器から供給する様にすると、エンジン高負荷域では実圧縮比を低くしても水素及び酸素の噴射によりシリンダー内圧力が相当高まる為、低圧縮比ながら圧縮端圧力は高く（高圧縮比の場合と同様に高い）、高膨張比化と合わせて熱効率の飛躍的改善が可能である（これはピストンの圧縮仕事を減らす事になり、水素や酸素を圧縮して供給容器内に貯蔵するに要した圧縮動力を一部回収した事になる）。以上の様に本発明は水素を燃料とする火花点火機関としても大きな潜在力を持つものである。Since air is not used as a working fluid in the present invention, the generation of NOx is cut off from the source and the discharge is zero. Of course, as shown in FIG. 4 (b), a small amount of air may be introduced to reduce the size of the oxygen supply container 15, but since a large amount of internal EGR is always performed, NOx generation is almost zero. Further, in the present invention, when the poppet valve 25 is closed, a large amount of high-temperature burned gas is confined as internal EGR, there is no gas cooling in the cylinder by not inhaling cold air as in the prior art, and the actual compression ratio Since the compression end temperature can be greatly increased because it can be freely changed (increased as much as necessary), premixed compression ignition combustion can be performed even in a low load range including the engine idle state (self-ignition). In the case of using a fuel having a high temperature, a method in which the actual expansion ratio is lowered and the actual compression ratio is increased to further increase the compression end temperature as shown in FIG. In the engine high load range, the control valves 34 and 33 are controlled to sufficiently cool the exhaust gas by the cooler 29 and sucked into the cylinder, and the actual compression ratio is also controlled to be low (the actual expansion ratio becomes high. This leads to a decrease in exhaust gas temperature), avoids the occurrence of knocks, and thus greatly expands the operating range of premixed compression ignition combustion. This premixed compression ignition combustion method is a rapid low temperature combustion in which each part in the combustion chamber starts combustion all at once, and there is no gas temperature gradient in the combustion chamber, and can be surely combusted even with an ultra lean mixture. Therefore, there is no need to control the intake air with a throttle valve, so there is no pump loss as in the conventional spark ignition combustion method, and the maximum combustion temperature can be kept low. Can greatly improve the thermal efficiency. Furthermore, in the past, when the actual expansion ratio is increased with respect to the actual compression ratio and the expansion ratio is increased, the output decreases due to the decrease in the effective intake stroke. Therefore, there is no reduction in output, and the thermal efficiency can be further improved by increasing the expansion ratio. In addition, if the piston, cylinder head, etc. have a heat insulating structure in the past, the output will be reduced due to the reduction in the intake air amount, but in the present invention, the oxygen injection amount and the fuel corresponding to this may be increased and injected. There is no reduction (even if the oxygen injection amount is increased to increase the oxygen concentration, knocking does not occur due to a large amount of internal EGR), and a low cooling loss is possible. Further, in the present invention as a diesel engine, the compression end temperature can be increased by a large amount of internal EGR. Therefore, the friction loss can be reduced by reducing the compression ratio, and the thermal efficiency can be drastically improved. Next, as a major feature of the present invention, the burned gas discharged from the cylinder is sufficiently cooled by the cooler 29 and then re-inhaled into the cylinder. The point is that most of the fuel gas can be re-inhaled into the cylinder. Therefore, HC and CO, which are harmful components in exhaust gas, and PM in diesel engines are also available. However, since these can be re-inhaled and re-burned, almost no harmful components are released into the atmosphere. It is possible to eliminate the need for a catalytic converter for purifying them. Furthermore, since most of the exhaust gas discharged from the cylinder can be re-inhaled into the cylinder, most of it can be recovered even if excessive oxygen is injected. But oxygen consumption does not increase.
For this reason, in the present invention as a diesel engine, PM is hardly generated in the combustion process, and in the present invention as a spark ignition engine, combustion is performed despite internal EGR being performed in a low load region including an engine idle state. It is activated and ignition and combustion by the spark plug are performed well (the combustion speed is high and irregular combustion does not occur). In this case, in order to perform high oxygen excess combustion, it is not necessary to continuously inject a large amount of oxygen. In the first cycle, a large amount of oxygen is injected to perform high oxygen excess combustion. It is sufficient to inject the amount necessary for combustion (although it is somewhat excessive). Hydrogen can be ignited by spark plugs even with an ultra-lean mixture, but has the disadvantage of a low combustion rate. However, according to the present invention, as described above, oxygen consumption does not increase even when high oxygen excess combustion is performed. Therefore, by performing this high oxygen excess combustion in a low load range including an engine idle state, ignition / ignition by an ignition plug is performed. It is possible to perform combustion with good combustion speed and high combustion speed (possible by ordinary spark ignition combustion without relying on premixed compression ignition combustion), and it is possible to greatly improve thermal efficiency together with the absence of pump loss It is. If the exhaust gas discharged from the cylinder is cooled to 100 ° C. or less by the cooler 29, condensation of moisture occurs. Therefore, it is possible to recover almost 100% even if not all can be recovered. 0. Furthermore, if hydrogen is supplied from a high-pressure hydrogen supply container in the same manner as oxygen, the pressure in the cylinder is considerably increased by injection of hydrogen and oxygen even if the actual compression ratio is lowered in the high engine load range. The compression end pressure is high (as high as in the case of a high compression ratio), and in combination with a high expansion ratio, it is possible to dramatically improve the thermal efficiency (this reduces the compression work of the piston and reduces hydrogen and oxygen This means that part of the compression power required to compress and store in the supply container has been recovered). As described above, the present invention has great potential as a spark ignition engine using hydrogen as a fuel.

本発明による酸素噴射式４サイクル内燃機関を示す図。The figure which shows the oxygen injection type 4 cycle internal combustion engine by this invention. ポペット弁の開閉時期変化を示す図。The figure which shows the opening-and-closing time change of a poppet valve. ポペット弁の開閉時期変化を示す図。The figure which shows the opening-and-closing time change of a poppet valve. 本発明における各種実施例を示す図。The figure which shows the various Examples in this invention. 電磁式可変動弁装置を示す図。The figure which shows an electromagnetic variable valve operating apparatus. ポペット弁２１，２５の開弁時期や閉弁時期を互いに独立的に制御する実施例の図。The figure of the Example which controls the valve-opening timing and valve-closing timing of the poppet valves 21 and 25 mutually independently. 本発明が火花点火機関である場合の実施例を示す図。The figure which shows the Example in case this invention is a spark ignition engine. 予混合圧縮着火燃焼が成立する運転領域を示す図。The figure which shows the operation area | region where premixing compression ignition combustion is materialized. 不安定燃焼やノックを回避する為の制御ルーチンを示す図。The figure which shows the control routine for avoiding unstable combustion and knock. 酸素濃度富化装置を有する酸素供給容器を示す図。The figure which shows the oxygen supply container which has an oxygen concentration enrichment apparatus.

Explanation of symbols

１は機関本体、２はクランク軸、３はベルト（チェーン）、４は可変動弁装置、５はプーリー（スプロケット）、６はハウジング、７はローター、８は進角室、９は遅角室、１０は油圧制御弁、１１はプランジャー、１２はスプール弁、１３はバネ、１４は電子制御ユニット、１５は酸素供給容器、１６はプレッシャーレギュレーター、１７はサージタンク、１８は圧力センサー、１９はピストン、２０・２１′は燃焼室、２１・２５・２１′・２５′・４５はポペット弁、２２はカム軸、２３はカム、２４はロッカーアーム、２６は排出通路、２７・３１はサージタンク、２８は放出通路、２９・２９′は冷却器、３０は連絡通路、３２は吸入通路、３３・３４は制御弁、３５・４０は電動アクチュエーター、３６はバイパス通路、３７は燃料噴射弁、３８は酸素噴射弁、３９は制御弁、４１は燃焼室の壁面、４２は空気層、４３は空気導入弁、４４はエァフローメーター、４６はハウジング、４７はプランジャー、４８・４９は電磁石、５０・５１はバネ、５２はドライバー、５３は点火プラグ、５４は酸素濃度富化装置、５５は酸素透過膜、５６は圧縮機、２２Ａ・２２Ｂはカム軸、４Ａ・４Ｂは可変動弁装置、１０Ａ・１０Ｂは油圧制御弁、２６′・２６″はガス流通路、２７′はサージタンク、３０′は冷却器の入口部、３６′はバイパス通路、３９′は制御弁である。 1 is an engine body, 2 is a crankshaft, 3 is a belt (chain), 4 is a variable valve gear, 5 is a pulley (sprocket), 6 is a housing, 7 is a rotor, 8 is an advance chamber, and 9 is a retard chamber. 10 is a hydraulic control valve, 11 is a plunger, 12 is a spool valve, 13 is a spring, 14 is an electronic control unit, 15 is an oxygen supply container, 16 is a pressure regulator, 17 is a surge tank, 18 is a pressure sensor, 19 is Pistons, 20 and 21 'are combustion chambers, 21, 25, 21', 25 'and 45 are poppet valves, 22 is a camshaft, 23 is a cam, 24 is a rocker arm, 26 is a discharge passage, 27 and 31 are surge tanks , 28 is a discharge passage, 29 and 29 'are coolers, 30 is a communication passage, 32 is a suction passage, 33 and 34 are control valves, 35 and 40 are electric actuators, 36 is a bypass passage, 37 is The fuel injection valve, 38 is an oxygen injection valve, 39 is a control valve, 41 is a combustion chamber wall, 42 is an air layer, 43 is an air introduction valve, 44 is an air flow meter, 46 is a housing, 46 is a plunger, 48 · 49 is an electromagnet, 50 and 51 are springs, 52 is a driver, 53 is a spark plug, 54 is an oxygen concentration enrichment device, 55 is an oxygen permeable membrane, 56 is a compressor, 22A and 22B are camshafts, and 4A and 4B are acceptable Fluctuating valve device, 10A and 10B are hydraulic control valves, 26 'and 26 "are gas flow passages, 27' is a surge tank, 30 'is an inlet of a cooler, 36' is a bypass passage, and 39 'is a control valve. .

Claims

In a four-cycle internal combustion engine having intake, compression, expansion, and exhaust strokes of the working fluid, and a poppet valve that controls the flow and shutoff of burned gas in the cylinder head, the oxygen supply container is provided, and the oxygen supply An oxygen injection valve that injects oxygen from the container and a fuel injection valve that injects fuel, and further includes a cooler that cools the burned gas discharged from the cylinder through the poppet valve, and is cooled by this cooler. The burned gas is introduced into the cylinder via the poppet valve, and the actual compression ratio is made variable by changing the closing timing of the poppet valve with a variable valve system according to the operating state of the engine. A featured oxygen injection type 4-cycle internal combustion engine.

2. The oxygen injection type four-cycle internal combustion engine according to claim 1, wherein the engine is a diesel engine that injects fuel into a compressed high-temperature gas containing oxygen to ignite and burn.

The oxygen injection type four-stroke internal combustion engine according to claim 1, which is a spark ignition type internal combustion engine in which a compressed hot gas containing oxygen and fuel is ignited by a spark plug and burned.

The oxygen according to any one of claims 1 to 3, wherein a flow rate of burned gas that bypasses the cooler is controlled by a control valve, thereby controlling a temperature of burned gas sucked into the cylinder. Injection type 4-cycle internal combustion engine.

The oxygen injection type four-cycle internal combustion engine according to any one of claims 1 to 4, wherein air is introduced into the cylinder via an air introduction valve.

6. The oxygen injection type four-cycle internal combustion engine according to claim 1, wherein premixed compression ignition combustion is performed in a predetermined operating region of the engine.