EP0781898A1 - Improvement to internal combustion engines - Google Patents

Improvement to internal combustion engines Download PDF

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Publication number
EP0781898A1
EP0781898A1 EP96490045A EP96490045A EP0781898A1 EP 0781898 A1 EP0781898 A1 EP 0781898A1 EP 96490045 A EP96490045 A EP 96490045A EP 96490045 A EP96490045 A EP 96490045A EP 0781898 A1 EP0781898 A1 EP 0781898A1
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EP
European Patent Office
Prior art keywords
valve
seat
valves
cylinder
exhaust valve
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EP96490045A
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German (de)
French (fr)
Inventor
Maurice-André Tacquet
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Individual
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Individual
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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01L—CYCLICALLY OPERATING VALVES FOR MACHINES OR ENGINES
    • F01L1/00—Valve-gear or valve arrangements, e.g. lift-valve gear
    • F01L1/28—Valve-gear or valve arrangements, e.g. lift-valve gear characterised by the provision of coaxial valves; characterised by the provision of valves co-operating with both intake and exhaust ports
    • F01L1/285—Coaxial intake and exhaust valves
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01L—CYCLICALLY OPERATING VALVES FOR MACHINES OR ENGINES
    • F01L9/00—Valve-gear or valve arrangements actuated non-mechanically
    • F01L9/10—Valve-gear or valve arrangements actuated non-mechanically by fluid means, e.g. hydraulic
    • F01L9/11—Valve-gear or valve arrangements actuated non-mechanically by fluid means, e.g. hydraulic in which the action of a cam is being transmitted to a valve by a liquid column
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01L—CYCLICALLY OPERATING VALVES FOR MACHINES OR ENGINES
    • F01L1/00—Valve-gear or valve arrangements, e.g. lift-valve gear
    • F01L1/02—Valve drive
    • F01L1/04—Valve drive by means of cams, camshafts, cam discs, eccentrics or the like
    • F01L1/08—Shape of cams

Definitions

  • the present invention relates to an internal combustion reciprocating engine cylinder head equipped with an intake valve and an exhaust valve per cylinder.
  • the valves are concentric with each other and the cylinder.
  • the exhaust valve is housed inside the intake valve and rests on it to ensure gas tightness of the cylinder.
  • the exhaust valve of annular shape, slides on a central post which is used as housing for the fuel injector for diesel engines or the spark plug for "otto" engines.
  • the displacement of the two valves is obtained by means of a single cam per cylinder and by means of a volume of oil supplied under pressure.
  • the invention generally relates to reciprocating internal combustion engines operating according to the 4-stroke cycle equipped with cylinder heads comprising intake valves and exhaust valves.
  • cylinder heads fitted with an intake valve and an exhaust valve per cylinder and the exhaust valve of which is concentric with the intake valve and housed therein.
  • the control of the two valves can be obtained by a single cam.
  • the intake and exhaust valves are separate and are supported by seats housed in the cylinder head. The movements of the intake and exhaust valves are controlled separately.
  • a camshaft fitted with one cam per cylinder pushes a "hydraulic control piston” which actuates the valves via a "volume of control oil supplied under pressure.
  • Part of the stroke of the control piston corresponds to the movement of the valve assembly while the other part of the stroke of the piston controls the movement of the exhaust valve alone, the intake valve then resting on its seat .
  • the parts exposed to combustion as well as the rubbing parts are cooled by an oil circulation.
  • the metal return spring is cooled by a flow of air taken from the charge air supply.
  • the exhaust valve is pressed against its seat by oil pressure.
  • the inside diameter of the exhaust seat is smaller than the guide diameter of the valve so that the higher the gas pressure in the cylinder, the higher the contact pressure of the exhaust valve on his seat.
  • the return spring has sufficient force to overcome the force which results from the pressure of the gases in the cylinder at the end of the rebound stroke.
  • the exhaust valve lift law is fast, because as soon as the valve is lifted off, the gas pressure adds to the force of the spring.
  • the space between the exterior of the exhaust valve and the interior of the intake valve forms the exhaust duct.
  • the section of this duct is made in such a way that it constitutes a diffuser which optimizes the flow of gases.
  • the single cam per cylinder actuates the two valves via a "hydraulic control piston” and a “control oil volume”.
  • This piston is also provided with a metal return spring. It has an end stop which allows to create a clearance between the piston, the roller and the cam when the exhaust valve is in the fully open position.

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Valve Device For Special Equipments (AREA)
  • Valve-Gear Or Valve Arrangements (AREA)

Abstract

The cylinder head includes, for each cylinder, two annular valves concentric between them and the cylinder. The inlet valve ensures sealing of gas by a valve seat in the cylinder, and has a return system which tends to maintain the valve on its seat in the open or closed position under the effect of hydraulic pressure which is applied to the exit valve. The exit valve is located at the interior of the inlet valve and resting on it, and ensures the sealing by use of a valve seat which is located on the inlet valve. It has a return mechanism which tends to lift it from the seat, and is opened and closed by a cam, a piston and a volume of oil. The position of the hydraulic piston which corresponds with the closure of the two valves puts the volume of oil in connection with a source of pressure such that the pressure applied on the exit valve is sufficient to assure the sealing on its seat, but insufficient for opening the inlet valve. A part of the course of the hydraulic piston controls the opening and closing of the exit valve, and the other part of its course controls the displacement of the assembly of two valves and hence the opening and closing of the inlet valves. The displacement of the two valves is controlled by a single cam by cylinder.

Description

La présente invention concerne une culasse de moteur alternatif à combustion interne équipée d'une soupape d'admission et d'une soupape d'échappement par cylindre. Les soupapes sont concentriques entre elles et le cylindre.The present invention relates to an internal combustion reciprocating engine cylinder head equipped with an intake valve and an exhaust valve per cylinder. The valves are concentric with each other and the cylinder.

La soupape d'échappement est logée à l'intérieur de la soupape d'admission et s'appuie sur celle-çi pour assurer l'étanchéité aux gaz du cylindre.The exhaust valve is housed inside the intake valve and rests on it to ensure gas tightness of the cylinder.

La soupape d'échappement, de forme annulaire, coulisse sur un poteau central qui sert de logement à l'injecteur de combustible pour les moteurs diesel ou à la bougie d'allumage pour les moteurs "otto".The exhaust valve, of annular shape, slides on a central post which is used as housing for the fuel injector for diesel engines or the spark plug for "otto" engines.

Le déplacement des deux soupapes est obtenu à l'aide d'une seule came par cylindre et par l'intermédiaire d'un volume d'huile alimenté sous pression.The displacement of the two valves is obtained by means of a single cam per cylinder and by means of a volume of oil supplied under pressure.

Domaine de l'invention.Field of the invention.

L'invention concerne en général des moteurs alternatifs à combustion interne fonctionnant selon le cycle à 4 temps équipés de culasses comportant des soupapes d'admission et des soupapes d'échappement.The invention generally relates to reciprocating internal combustion engines operating according to the 4-stroke cycle equipped with cylinder heads comprising intake valves and exhaust valves.

En particulier, elle concerne des culasses équipées d'une soupape d'admission et d'une soupape d'échappement par cylindre et dont la soupape d'échappement est concentrique à la soupape d'admission et logée à l'intérieur de celle-çi. La commande des deux soupapes pouvant être obtenue par une seule came.In particular, it relates to cylinder heads fitted with an intake valve and an exhaust valve per cylinder and the exhaust valve of which is concentric with the intake valve and housed therein. . The control of the two valves can be obtained by a single cam.

Technique antérieure.Prior art.

Dans la quasi totalité des moteurs alternatifs à combustion interne en cours de production et fonctionnant selon le cycle à 4 temps, les soupapes d'admission et d'échappement sont séparées et s'appuient sur des sièges logés dans la culasse. Les déplacements des soupapes d'admission et d'échappement sont commandés séparément.In almost all of the internal combustion reciprocating engines in production and operating according to the 4-stroke cycle, the intake and exhaust valves are separate and are supported by seats housed in the cylinder head. The movements of the intake and exhaust valves are controlled separately.

Cette disposition pose des problèmes concernant :

  • la dissymétrie des déformations mécaniques et thermiques.
  • la difficulté à orienter les flux de gaz dans le cylindre.
  • la difficulté à maitriser une stratification des gaz dans le cylindre.
  • la forme de la tête du piston par rapport au déplacement des soupapes.
  • les pertes de chaleur par les parois.
This provision poses problems concerning:
  • the asymmetry of mechanical and thermal deformations.
  • difficulty directing gas flows in the cylinder.
  • the difficulty in mastering a stratification of the gases in the cylinder.
  • the shape of the piston head relative to the displacement of the valves.
  • heat losses through the walls.

Tous ces problèmes sont simplifiés grâce à la présente invention.All of these problems are simplified by the present invention.

Avantages de l'invention :Advantages of the invention:

  • * L'ensemble cylindre, soupapes, chambre de combustion est axisymétrique et offre peu de surface refroidie. Les contraintes mécaniques et thermiques sont plus uniformes et créent donc moins de distorsions mécaniques et de concentrations de contraintes. Les pertes de chaleur par les parois sont réduites, ce qui améliore le rendement global du moteur. La forme du conduit d'admission peut engendrer un mouvement tournant de l'air qui est admis dans le cylindre. L'air frais, plus dense que les gaz de combustion qui peuvent rester dans le cylindre, aura tendance à lécher les parois extérieures par effet de centrifugation, limitant ainsi les pertes de calories aux parois. A la fin de la course de compression, les gaz chauds résiduels à faible teneur en oxygène, formeront un noyau chaud central favorable à la rapidité de la combustion et à la réduction de production de NOx.* The cylinder, valves, combustion chamber assembly is axisymmetric and offers little cooled surface. Mechanical and thermal stresses are more uniform and therefore create less mechanical distortion and stress concentrations. The heat losses through the walls are reduced, which improves the overall efficiency of the engine. The shape of the intake duct can generate a rotating movement of the air which is admitted into the cylinder. The fresh air, denser than the combustion gases which can remain in the cylinder, will tend to lick the external walls by centrifugal effect, thus limiting the losses of calories to the walls. At the end of the compression stroke, the residual hot gases with a low oxygen content will form a central hot core favorable to the speed of combustion and the reduction of NOx production.
  • * La section du conduit d'échappement situé entre le diamètre extérieur de la soupape d'échappement et le diamètre intérieur de la soupape d'admission peut constituer un diffuseur qui optimise l'écoulement des gaz.* The section of the exhaust duct located between the outside diameter of the exhaust valve and the inside diameter of the intake valve can constitute a diffuser which optimizes the flow of gases.
  • * La disposition de la soupape d'échappement est telle que sa fermeture peut être retardée après le point mort haut sans qu'il soit nécessaire de creuser un logement dans la tête de piston. Il devient ainsi possible d'augmenter la quantité de gaz brûlés qui resteront dans le cylindre et, en particulier, sur les moteurs à 2,4,8,16 cylindres pour lesquels une disposition appropriée des conduits d'échappement permettra d'utiliser les pulsations de pression dûes au bouffées d'échappement d'autres cylindres. Cette augmentation de la quantité de gaz recyclés est favorable à la réduction de la production de NOx.* The arrangement of the exhaust valve is such that its closing can be delayed after top dead center without it being necessary to dig a housing in the piston head. It thus becomes possible to increase the quantity of burnt gases which will remain in the cylinder and, in particular, on 2,4,8,16 cylinder engines for which an appropriate arrangement of the exhaust ducts will make it possible to use the pulsations. pressure due to exhaust puffs from other cylinders. This increase in the quantity of recycled gas is favorable to the reduction of NOx production.
  • * Cette disposition des soupapes convient bien à des moteurs sur lesquels l'arbre à cames serait muni d'un système de variation de calage angulaire en cours de fonctionnement Ce système permet d'obtenir un taux de compression élevé au démarrage et un taux de compression réduit pour le fonctionnement à forte puissance.* This arrangement of the valves is suitable for engines on which the camshaft would be provided with a system of variation of angular setting during operation. This system makes it possible to obtain a high compression ratio at start-up and a compression ratio. reduced for high power operation.
Description du fonctionnement. ( voir fig n° 1 ) Description of operation. (see fig n ° 1)

Un arbre à cames muni d'une came par cylindre pousse un " piston hydraulique de commande " qui actionne les soupapes par l'intermédiaire d'un "volume d'huile de commande alimenté sous pression.A camshaft fitted with one cam per cylinder pushes a "hydraulic control piston" which actuates the valves via a "volume of control oil supplied under pressure.

Une partie de la course du piston de commande correspond au déplacement de l'ensemble des soupapes tandis que l'autre partie de la course du piston commande le déplacement de la soupape d'échappement seule, la soupape d'admission reposant alors sur son siège.Part of the stroke of the control piston corresponds to the movement of the valve assembly while the other part of the stroke of the piston controls the movement of the exhaust valve alone, the intake valve then resting on its seat .

Lorsque le piston de commande se trouve dans la position qui correspond à la fermeture des deux soupapes, ( c'est la position représentée par la figure n° 1 ) celui-çi découvre une alimentation en huile sous pression qui a pour but de compenser les fuites éventuelles du circuit, et surtout d'engendrer une force d'appui sur la soupape d'échappement suffisante pour assurer l'étanchéité du siège sans pour autant décoller la soupape d'admission du sien. Cette alimentation fait également office de compensation des dilatations et des usures des pièces.When the control piston is in the position which corresponds to the closing of the two valves, (it is the position represented by figure n ° 1) this one discovers a supply of pressurized oil which aims to compensate for the possible leaks from the circuit, and above all to generate a pressing force on the exhaust valve sufficient to seal the seat without taking off the intake valve from its own. This power supply also acts as compensation for expansions and wear of the parts.

La figure n° 1 représente les soupapes en position fermées prêtes pour la combustion et la détente.

  • 1) Compression, combustion, détente motrice.
    La soupape d'admission est appuyée sur son siège grâce à un système de rappel ( ressort mécanique ou pneumatique ).
    La soupape d'échappememt est appuyée sur la soupape d'admission qui lui sert de siège. La force d'appui est assurée par une alimentation en huile sous pres sion qui engendre une force suffisante pour assurer l'étanchéité sans excéder la force de rappel de la soupape d'admission.
    Dans cette position, les positions respectives du piston de commande et de la soupape d'échappement sont déconnectées. ll y a rattrapage automatique des dilatations et des usures.
  • 2) Ouverture de la soupape d'échappement.
    Le piston de commande suit le profil de la came et isole le volume d'huile de commande de l'alimentation sous pression. La pression de l'huile de commande chute et la soupape d'échappement se soulève de son siège par l'effet du système de rappel de la soupape d'échappement ( ressort mécanique ou pneumatique ) et de la pression des gaz dans le cylindre.
    Lorsque le piston de commande atteint sa butée de fin de course, la soupape d'échappement est complétement levée. Les efforts sur le galet et la came sont annulés par un jeu qui facilite le renouvellement des films d'huile.
  • 3) Fermeture de la soupape d'échappement et ouverture de la soupape d'admission.
    La came repousse le piston de commande. Dans la première partie de sa course, le piston de commande repousse la soupape d'échappement jusqu'au moment où il met le volume d'huile de commande en communication avec l'alimentation sous pression. La soupape d'échappement s'appuie sur la soupape d'admission qui lui sert de siège. En poursuivant sa course, le piston de commande ferme à nouveau la communication avec l'alimentation en huile sous pression et provoque ainsi l'ouverture de la soupape d'admission, la soupape d'échappement étant évidemment toujours en contact avec la soupape d'admission.
  • 4) Fermeture de la soupape d'admission.
    Lorsque le profil de la came permet au piston de commande de reculer, le système de rappel de la soupape d'admission repousse l'ensemble des deux soupapes jusqu'à la position initiale : soupapes fermées. Le piston de commande peut être muni d'un système de rappel mécanique ou pneumatique qui a pour effet de limiter les efforts de rappel des soupapes.
Figure 1 shows the valves in the closed position ready for combustion and expansion.
  • 1) Compression, combustion, motor relaxation.
    The intake valve is supported on its seat thanks to a return system (mechanical or pneumatic spring).
    The exhaust valve is supported on the intake valve which serves as its seat. The supporting force is ensured by an oil supply under pres sion which generates sufficient force to seal without exceeding the return force of the intake valve.
    In this position, the respective positions of the control piston and the exhaust valve are disconnected. There is automatic catching up of expansions and wear.
  • 2) Opening the exhaust valve.
    The control piston follows the cam profile and isolates the volume of control oil from the pressure supply. The pressure of the control oil drops and the exhaust valve lifts from its seat by the effect of the return system of the exhaust valve (mechanical or pneumatic spring) and the pressure of the gases in the cylinder.
    When the control piston reaches its end stop, the exhaust valve is completely lifted. The forces on the roller and the cam are canceled by a play which facilitates the renewal of the oil films.
  • 3) Closing the exhaust valve and opening the intake valve.
    The cam pushes back the control piston. In the first part of its stroke, the control piston pushes the exhaust valve until it puts the volume of control oil in communication with the pressurized supply. The exhaust valve rests on the intake valve which serves as its seat. By continuing its stroke, the control piston again closes the communication with the pressurized oil supply and thus causes the opening of the intake valve, the exhaust valve obviously being always in contact with the admission.
  • 4) Closing of the intake valve.
    When the profile of the cam allows the control piston to move back, the return system of the intake valve pushes all of the two valves back to the initial position: valves closed. The control piston can be provided with a mechanical or pneumatic return system which has the effect of limiting the valve return forces.

Description de la réalisation préférée :Description of the preferred embodiment:

Selon un mode préféré de réalisation représenté par la figure n° 1,

  • La soupape d'admission de forme annulaire est rappellée sur son siège par un ressort métallique. Le siège de la soupape est une pièce rapportée qui comporte le passage d'arrivée d'air muni d'ailettes directionnelles, cette pièce pouvant être obtenue par un procédé de fonderie de précision. Un refroidissement et une lubrification des segments d'étanchéité entre les gaz d'échappement et l'air d'admission sont assurés par une circulation d'huile mise en vitesse par des gicleurs tangentiels. La soupape d'admission comporte un siège sur lequel s'appuie la soupape d'échappement.
  • La soupape d'échappement de forme annulaire coulisse sur un poteau central qui comporte en son centre un logement pour l'injecteur d'un moteur diesel ou diesel-gaz ou pour une bougie d'allumage pour un moteur "otto".
According to a preferred embodiment represented by FIG. 1,
  • The ring-shaped intake valve is returned to its seat by a metal spring. The seat of the valve is an added part which includes the air inlet passage provided with directional fins, this part being obtainable by a precision casting process. Cooling and lubrication of the sealing rings between the exhaust gases and the intake air are ensured by an oil circulation speeded up by tangential nozzles. The intake valve has a seat on which the exhaust valve rests.
  • The annular-shaped exhaust valve slides on a central post which has in its center a housing for the injector of a diesel or diesel-gas engine or for a spark plug for an "otto" engine.

Les parties exposées à la combustion ainsi que les parties frottantes sont refroidies par une circulation d'huile. Le ressort métallique de rappel est refroidi par un débit d'air prélevé sur l'alimentation en air de suralimentation. La soupape d'échappement est appuyée sur son siège par une pression d'huile. Le diamètre intérieur du siège d'échappement est plus petit que le diamètre de guidage de la soupape de telle façon que, plus la pression des gaz dans le cylindre est élevée, plus forte est la pression d'appui de la soupape d'échappement sur son siège.The parts exposed to combustion as well as the rubbing parts are cooled by an oil circulation. The metal return spring is cooled by a flow of air taken from the charge air supply. The exhaust valve is pressed against its seat by oil pressure. The inside diameter of the exhaust seat is smaller than the guide diameter of the valve so that the higher the gas pressure in the cylinder, the higher the contact pressure of the exhaust valve on his seat.

Le ressort de rappel a une force suffisante pour vaincre la force qui résulte de la pression des gaz dans le cylindre à la fin de la course de détente. La loi de levée de la soupape d'échappement est rapide, car dès le décollement de la soupape, la pression des gaz s'ajoute à la force du ressort.The return spring has sufficient force to overcome the force which results from the pressure of the gases in the cylinder at the end of the rebound stroke. The exhaust valve lift law is fast, because as soon as the valve is lifted off, the gas pressure adds to the force of the spring.

L'espace situé entre l'extérieur de la soupape d'échappement et l'intérieur de la soupape d'admission forme le conduit d'échappement. La section de ce conduit est réalisée de telle façon qu'il constitue un diffuseur qui optimise l'écoulement des gaz.The space between the exterior of the exhaust valve and the interior of the intake valve forms the exhaust duct. The section of this duct is made in such a way that it constitutes a diffuser which optimizes the flow of gases.

L'unique came par cylindre actionne les deux soupapes par l'intermédiaire d'un "piston hydraulique de commande" et d'un "volume d'huile de commande". Ce piston est lui aussi muni d'un ressort métallique de rappel. ll a une butée de fin de course qui permet de créer un jeu entre le piston, le galet et la came lorsque la soupape d'échappement est en position d'ouverture maximum.The single cam per cylinder actuates the two valves via a "hydraulic control piston" and a "control oil volume". This piston is also provided with a metal return spring. It has an end stop which allows to create a clearance between the piston, the roller and the cam when the exhaust valve is in the fully open position.

Lorsque la levée du piston de commande correspond à la fermeture des deux soupapes, (ce qui est le cas dans la figure n° 1), le piston met le volume de commande en communication avec un circuit d'alimentation en huile sous pression. Cette pression est suffisante pour assurer l'étanchéité initiale de la soupape d'échappement, mais reste insuffisante pour vaincre la force du ressort de rappel de la soupape d'admission.When the lift of the control piston corresponds to the closing of the two valves, (which is the case in figure n ° 1), the piston puts the control volume in communication with a pressurized oil supply circuit. This pressure is sufficient to ensure the initial tightness of the exhaust valve, but remains insufficient to overcome the force of the return spring of the intake valve.

Description de variantes :Description of variants:

  • * Dans une variante représentée par la figure n° 2, les rappels des soupapes sont réalisés par une pression d'air. Cette pression d'air peut être rendue proportionnelle au déplacement des soupapes et du piston si les volumes de rappel sont munis de clapets anti-retour. Le rappel du piston de commande est obtenu par la pression du circuit d'alimentation d'huile du circuit de commande.* In a variant represented by FIG. 2, the valve recalls are produced by air pressure. This air pressure can be made proportional to the movement of the valves and the piston if the return volumes are fitted with non-return valves. The return of the control piston is obtained by the pressure of the oil supply circuit of the control circuit.
  • * Dans une variante représentée par la figure n° 3, le diamètre intérieur de la soupape d'échappement est plus grand que le diamètre de guidage de la soupape de telle façon la pression des gaz dans le cylindre a toujours tendance à décoller la soupape de son siège. Dans cette configuration, la pression d'alimentation en huile doit être suffisamment élevée pour assurer l'étanchéité aux gaz, même à la pression maximale de combustion. La force de rappel de la soupape d'admission doit donc être augmentée en conséquence. Etant donné que la pression des gaz du cylindre a toujours tendance à ouvrir la soupape d'échappement, il pourra être envisagé, dans certains cas, de ne pas munir cette soupape de système de rappel.* In a variant represented by figure n ° 3, the inside diameter of the exhaust valve is larger than the guide diameter of the valve so that the gas pressure in the cylinder always tends to take off the valve. his seat. In this configuration, the oil supply pressure must be high enough to ensure gas tightness, even at the maximum combustion pressure. The return force of the intake valve must therefore be increased accordingly. Since the pressure of the cylinder gases always tends to open the exhaust valve, it may be envisaged, in certain cases, not to provide this valve with a return system.
  • * Dans une variante représentée par la figure n° 4, l'arbre à cames est situé au dessus de la culasse. Cette variante peut être équipée de ressorts mécaniques ou pneumatiques.* In a variant shown in Figure 4, the camshaft is located above the cylinder head. This variant can be fitted with mechanical or pneumatic springs.

Claims (3)

Culasse de moteur alternatif à combustion interne fonctionnant selon le cycle à 4 temps caractérisée en ce qu'elle comporte, pour chaque cylindre, deux soupapes de forme annulaire, concentriques entre elles et le cylindre. La soupape d'admission assure l'étanchéité aux gaz par un siège logé dans la culasse, est munie d'un système de rappel qui tend à la ramener sur son siège, s'ouvre et se ferme sous l'effet d'une pression hydraulique qui s'applique sur la soupape d'échappement. La soupape d'échappement, logée à l'intérieur de la soupape d'admission, assure l'étanchéité aux gaz par un siège logé sur la soupape d'admission, est munie d'un rappel qui tend à la soulever de son siège, s'ouvre et se ferme par l'intermédiaire d'une came, d'un piston et d'un volume d'huile. la position du piston hydraulique qui correspond à la fermeture des deux soupapes met le volume d'huile de commande en liaison avec une alimentation sous pression telle que la pression appliquée sur la soupape d'échappement soit suffisante pour assurer l'étanchéité sur son siège, mais insuffisante pour ouvrir la soupape d'admission. Une partie de la course du piston hydraulique commande l'ouverture et la fermeture de la soupape d'échappement tandis que l'autre partie de sa course commande le déplacemnt de l'ensemble des deux soupapes, c'est à dire l'ouverture et la fermeture de la soupape d'admission.Le déplacement des deux soupapes est commandé par une seule came par cylindre.Cylinder head of reciprocating internal combustion engine operating according to the 4-stroke cycle characterized in that it comprises, for each cylinder, two valves of annular shape, concentric between them and the cylinder. The intake valve ensures gas tightness by a seat housed in the cylinder head, is provided with a return system which tends to bring it back on its seat, opens and closes under the effect of pressure hydraulically applied to the exhaust valve. The exhaust valve, housed inside the intake valve, ensures gas tightness by a seat housed on the intake valve, is provided with a return which tends to lift it from its seat, opens and closes via a cam, a piston and an oil volume. the position of the hydraulic piston which corresponds to the closing of the two valves places the volume of control oil in connection with a pressurized supply such that the pressure applied to the exhaust valve is sufficient to ensure the seal on its seat, but insufficient to open the intake valve. Part of the stroke of the hydraulic piston controls the opening and closing of the exhaust valve while the other part of its stroke controls the movement of the assembly of the two valves, that is to say the opening and closing the intake valve. The movement of the two valves is controlled by a single cam per cylinder. Dispositif selon la revendication n° 1 caractérisé en ce que le piston de commande hydraulique a une butée de fin de course qui correspond à l'ouverture maximale de la soupape d'échappement.Device according to Claim 1, characterized in that the hydraulic control piston has an end-of-travel stop which corresponds to the maximum opening of the exhaust valve. Dispositif selon les revendications n° 1 et 2 caractérisé en ce que le siège de la soupape d'admission est réalisé en une pièce rapportée dans la culasse et comporte le conduit de passage de l'air d'admission ainsi que des ailettes directionnelles. Cette pièce pouvant être obtenue par un procédé de fonderie de précision.Device according to Claims 1 and 2, characterized in that the seat of the intake valve is produced in an attached part in the cylinder head and comprises the duct for the passage of the intake air as well as directional fins. This part can be obtained by a precision foundry process.
EP96490045A 1995-11-29 1996-11-20 Improvement to internal combustion engines Withdrawn EP0781898A1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
FR9514507 1995-11-29
FR9514507A FR2741668B1 (en) 1995-11-29 1995-11-29 IMPROVEMENTS ON INTERNAL COMBUSTION ALTERNATIVE ENGINES, THOSE INCLUDING CONCENTRIC VALVE HEADS

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EP0781898A1 true EP0781898A1 (en) 1997-07-02

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Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2000058609A1 (en) * 1999-03-23 2000-10-05 Igors Pancakovs Gas distributor for internal combustion engine
CZ303732B6 (en) * 2011-05-03 2013-04-10 Knob Engines S.R.O. Cylinder head with ring-shaped valve for internal combustion engine

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE200793C (en) *
GB416496A (en) * 1933-03-15 1934-09-17 Charles Edward Maclea March Improvements in or relating to valves for fluid pressure engines
FR852101A (en) * 1939-03-25 1940-01-24 For a gas engine cylinder head with combined, refrigerated, single-control valves and discharge gas reserve chamber
WO1995008052A1 (en) * 1993-09-13 1995-03-23 S.N.C. Melchior Technologie Improvements to internal combustion engines

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE200793C (en) *
GB416496A (en) * 1933-03-15 1934-09-17 Charles Edward Maclea March Improvements in or relating to valves for fluid pressure engines
FR852101A (en) * 1939-03-25 1940-01-24 For a gas engine cylinder head with combined, refrigerated, single-control valves and discharge gas reserve chamber
WO1995008052A1 (en) * 1993-09-13 1995-03-23 S.N.C. Melchior Technologie Improvements to internal combustion engines

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FR2741668A1 (en) 1997-05-30
FR2741668B1 (en) 1998-03-20

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