EP3408513A1 - Variable compression ratio internal combustion engine with two mixing zones, notably for a motor vehicle, and method of injection for such a vehicle - Google Patents

Variable compression ratio internal combustion engine with two mixing zones, notably for a motor vehicle, and method of injection for such a vehicle

Info

Publication number
EP3408513A1
EP3408513A1 EP17700172.4A EP17700172A EP3408513A1 EP 3408513 A1 EP3408513 A1 EP 3408513A1 EP 17700172 A EP17700172 A EP 17700172A EP 3408513 A1 EP3408513 A1 EP 3408513A1
Authority
EP
European Patent Office
Prior art keywords
fuel
compression ratio
bowl
piston
internal combustion
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP17700172.4A
Other languages
German (de)
French (fr)
Inventor
Gaetano DE PAOLA
Jean-Marc Zaccardi
Philippe DEGEILH
Stéphane CHEVILLARD
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
IFP Energies Nouvelles IFPEN
Original Assignee
IFP Energies Nouvelles IFPEN
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by IFP Energies Nouvelles IFPEN filed Critical IFP Energies Nouvelles IFPEN
Publication of EP3408513A1 publication Critical patent/EP3408513A1/en
Withdrawn legal-status Critical Current

Links

Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02B—INTERNAL-COMBUSTION PISTON ENGINES; COMBUSTION ENGINES IN GENERAL
    • F02B23/00—Other engines characterised by special shape or construction of combustion chambers to improve operation
    • F02B23/02—Other engines characterised by special shape or construction of combustion chambers to improve operation with compression ignition
    • F02B23/06—Other engines characterised by special shape or construction of combustion chambers to improve operation with compression ignition the combustion space being arranged in working piston
    • F02B23/0678—Unconventional, complex or non-rotationally symmetrical shapes of the combustion space, e.g. flower like, having special shapes related to the orientation of the fuel spray jets
    • F02B23/0693—Unconventional, complex or non-rotationally symmetrical shapes of the combustion space, e.g. flower like, having special shapes related to the orientation of the fuel spray jets the combustion space consisting of step-wise widened multiple zones of different depth
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02B—INTERNAL-COMBUSTION PISTON ENGINES; COMBUSTION ENGINES IN GENERAL
    • F02B23/00—Other engines characterised by special shape or construction of combustion chambers to improve operation
    • F02B23/02—Other engines characterised by special shape or construction of combustion chambers to improve operation with compression ignition
    • F02B23/06—Other engines characterised by special shape or construction of combustion chambers to improve operation with compression ignition the combustion space being arranged in working piston
    • F02B23/0645—Details related to the fuel injector or the fuel spray
    • F02B23/0648—Means or methods to improve the spray dispersion, evaporation or ignition
    • F02B23/0651—Means or methods to improve the spray dispersion, evaporation or ignition the fuel spray impinging on reflecting surfaces or being specially guided throughout the combustion space
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02B—INTERNAL-COMBUSTION PISTON ENGINES; COMBUSTION ENGINES IN GENERAL
    • F02B23/00—Other engines characterised by special shape or construction of combustion chambers to improve operation
    • F02B23/02—Other engines characterised by special shape or construction of combustion chambers to improve operation with compression ignition
    • F02B23/06—Other engines characterised by special shape or construction of combustion chambers to improve operation with compression ignition the combustion space being arranged in working piston
    • F02B23/0645—Details related to the fuel injector or the fuel spray
    • F02B23/0666—Details related to the fuel injector or the fuel spray having a single fuel spray jet per injector nozzle
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02B—INTERNAL-COMBUSTION PISTON ENGINES; COMBUSTION ENGINES IN GENERAL
    • F02B23/00—Other engines characterised by special shape or construction of combustion chambers to improve operation
    • F02B23/02—Other engines characterised by special shape or construction of combustion chambers to improve operation with compression ignition
    • F02B23/06—Other engines characterised by special shape or construction of combustion chambers to improve operation with compression ignition the combustion space being arranged in working piston
    • F02B23/0645—Details related to the fuel injector or the fuel spray
    • F02B23/0669—Details related to the fuel injector or the fuel spray having multiple fuel spray jets per injector nozzle
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02B—INTERNAL-COMBUSTION PISTON ENGINES; COMBUSTION ENGINES IN GENERAL
    • F02B23/00—Other engines characterised by special shape or construction of combustion chambers to improve operation
    • F02B23/02—Other engines characterised by special shape or construction of combustion chambers to improve operation with compression ignition
    • F02B23/06—Other engines characterised by special shape or construction of combustion chambers to improve operation with compression ignition the combustion space being arranged in working piston
    • F02B23/0672—Omega-piston bowl, i.e. the combustion space having a central projection pointing towards the cylinder head and the surrounding wall being inclined towards the cylinder center axis
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02B—INTERNAL-COMBUSTION PISTON ENGINES; COMBUSTION ENGINES IN GENERAL
    • F02B75/00—Other engines
    • F02B75/04—Engines with variable distances between pistons at top dead-centre positions and cylinder heads
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02D—CONTROLLING COMBUSTION ENGINES
    • F02D15/00—Varying compression ratio
    • F02D15/02—Varying compression ratio by alteration or displacement of piston stroke
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
    • Y02T10/00—Road transport of goods or passengers
    • Y02T10/10—Internal combustion engine [ICE] based vehicles
    • Y02T10/12—Improving ICE efficiencies

Definitions

  • the present invention relates to an internal combustion engine with direct injection of fuel with variable compression ratio, in particular for a motor vehicle, and to an injection method for such an engine.
  • the combustion systems of internal combustion engines must meet the demands of reducing pollutant emissions, increasing torque and specific power, and reducing combustion noise, while remaining compatible with the performance criteria. endurance.
  • the compression ratio of an engine is the ratio between the volume of the combustion chamber when the piston is in the bottom dead center position and the volume of this chamber when in the neutral position. high, says dead volume.
  • some of these devices offer the possibility of changing the compression ratio of this engine by changing the dead volume of the combustion chamber at the top dead center of the piston. For this, simply change the final position of the piston relative to the cylinder head when it is at its top dead center.
  • this type of engine generally comprises a cylinder, a piston comprising a pin disposed in a concave bowl and sliding in this cylinder in a reciprocating rectilinear movement, admission means of an oxidizer, means for exhausting burnt gases, means for varying the position of the top dead center of the piston, and injection means for injecting a fuel into the combustion chamber of this engine.
  • the fuel injection means comprise an injector with two rows of superimposed injection ports for injecting the fuel in the form of one or two layers of fuel jets. superimposed.
  • the fuel is injected in a single layer of jets and, for a low compression ratio, the fuel is injected at the two ply angles.
  • This type of engine therefore requires a multi-layer fuel injector which is complex in design and must necessarily be associated with a sophisticated control device to make operational one and / or the other ply of fuel jets.
  • the present invention proposes to remedy these drawbacks with a motor which comprises a conventional injector with a single ply of fuel jets which injects the fuel into combustion and combustion zones of the combustion chamber, whatever the rate compressor used for the engine.
  • the present invention relates to a variable compression ratio direct injection internal combustion engine comprising at least one cylinder, a cylinder head carrying a fuel injection means projecting fuel in a single layer of fuel jets, a sliding piston in this cylinder, and a combustion chamber delimited on one side by the upper face of the piston having a pin extending towards the cylinder head and disposed in the center of a concave bowl, characterized in that the combustion chamber comprises at least two mixing zones in which the fuel jets are injected, one of the zones being used for a maximum compression ratio and the other of the zones being used for a minimum compression ratio.
  • One of the zones may be associated with the other zones for the minimum compression ratio.
  • the mixing zones can be located axially one above the other.
  • the mixing zones may be delimited from one another by a radial projection.
  • One of the mixing zones may include a concave surface connected to a convex surface to form the bottom portion of a toric volume.
  • the other of the mixing zones may comprise a concave surface connected to a convex surface to form a barrier.
  • the engine may comprise a piston with a bowl which has a bowl diameter BD, a neck diameter GD, a low bend diameter ID1, a top bend diameter ID2, a height H of teat, a height L of the bowl , a height L1 of the inflection diameter ID1, an inclination angle a3, a radius R for the rounded concave surface of the torus and a radius R2 for the concave rounded surface, the dimensions of the bowl being able to satisfy at least one of following conditions:
  • the ratio BD / L is substantially between 1, 3 and 1, 8,
  • the ratio GD / BD is substantially between 0.9 and 0.95 for the aerodynamics of the torus and the recovery of the fuel jets
  • the ratio H / L is substantially less than 0.6 and substantially greater than 0.5 to minimize the volume of oxidant between the nose of the injector and the nipple,
  • the ratio L / L1 is substantially between 1, 15 and 1, 7
  • the ratio R2 / R is substantially between 0.25 and 1,
  • the ratio GD / ID is substantially between 0.65 and 0.9
  • A3 is substantially between 50 and 70 °
  • ⁇ BD bowl diameter is smaller than ID2 diameter.
  • the invention also relates to a fuel injection method for a variable compression ratio direct injection internal combustion engine comprising at least one cylinder, a cylinder head carrying a fuel injection means throwing fuel in a single layer of fuel. jets of fuel, a piston sliding in this cylinder, and a combustion chamber delimited on one side by the upper face of the piston having a pin extending in the direction of the cylinder head and disposed in the center of a concave bowl, characterized in that, for a maximum compression ratio, the fuel is injected into a mixing zone of the combustion chamber and, for a minimum compression ratio, the fuel is injected into another mixing zone of said combustion chamber. For the minimum compression ratio, the fuel can be injected into the two mixing zones.
  • FIG. 1 which shows an internal combustion engine with a variable compression ratio according to the invention, in a configuration for a compression ratio
  • FIG. 2 which is another view of the engine of FIG. 1 for another compression ratio
  • FIG. 3 which is a partial large-scale local view of the profile of the bowl of FIGS. 1 and 2.
  • FIGS. 1 and 2 illustrate, in a nonlimiting manner, an internal combustion engine with variable compression ratio and with direct injection of fuel.
  • This engine is advantageously a compression ignition engine using a diesel type fuel.
  • any other fuel having the physicochemical characteristics allowing the operation of a compression ignition type engine including a direct injection system can be used, such as kerosene.
  • This engine comprises at least one cylinder 10, a cylinder head 12 closing the cylinder in the upper part, fuel injection means 14 carried by the cylinder head and a piston 1 6 XX axis sliding in the cylinder in a reciprocating rectilinear motion.
  • This engine also comprises a flue exhaust means 18 with at least one exhaust pipe 20 whose opening can be controlled by any means, such as for example an exhaust valve 22 and an intake means 24.
  • an oxidizer with at least one intake manifold 26 whose opening can be controlled by any means, such as an intake valve 28.
  • oxidizer it includes air at ambient pressure or supercharged air or a mixture of air (supercharged or not) with flue gas.
  • the injection means comprise a fuel injector 30, preferably arranged in the axis XX of the piston, whose nose comprises a multiplicity of orifices through which the fuel is sprayed and projected towards the combustion chamber 32 of the piston. engine. It is from this injector that the projected fuel forms a single layer
  • nappe angle it is understood the angle at the top that forms the cone of jets coming from the injector and whose imaginary peripheral wall passes through all the axes 38 of the fuel jets 36.
  • the combustion chamber 32 is delimited by the internal face of the cylinder head 40 opposite the piston, the circular inner wall 41 of the cylinder 10 and the upper face 42 of the piston 1 6.
  • This upper face of the piston comprises a concave bowl 44, here of axis coincident with that of the cylinder, whose concavity is turned towards the cylinder head and which houses a pin 46 located substantially in the center of the bowl, which rises towards the cylinder head 12 , preferably being coaxial with the axis of the fuel jet web.
  • the stud 46 of generally frustoconical shape, has an apex 48 preferably rounded, continuing, deviating symmetrically from the axis XX towards the outside of the piston, by an inclined surface 50 substantially rectilinear to arrive at a bottom 52 of the bowl.
  • the bottom of this bowl is rounded with a curved rounded concave surface 54, called the inner rounded surface, connected to the bottom of the inclined sidewall and another concave rounded surface 56 in an arc of a circle, said surface outer rounded, connected at one end to the low end of the inner rounded surface and the other of its ends to a side wall 58, here substantially rounded towards the axis XX, thereby forming a radial projection 59 in the direction of the stud.
  • the two rounded surfaces 54 and 56 thus delimit the lower part of a toric volume 60 (or torus) delimited at the top by the seam 59.
  • the rounded side wall 58 continues, always away from the axis XX, by a concave rounded surface 62 which is continued by an outer convex surface 64 which arrives at a flat surface 66 advancing to the vicinity of the wall 41 of the cylinder.
  • the surfaces 62 and 64 then forming a barrier 67 whose role will be explained in the following description.
  • the combustion chamber thus comprises two distinct zones Z1 and Z2 which ensure the mixing between the oxidant they contain (air [supercharged or not] or mixture of air and recirculated flue gas) and the fuel coming from the injector, as well as the combustion of the carbureted mixture thus formed when the physicochemical conditions of this mixture are ensured to ensure such combustion.
  • the zone Z1 which is delimited by the pin 46, the torus 60 of the bottom of the bowl and the radial projection 59, forms the lower zone of the combustion chamber.
  • the engine of FIGS. 1 and 2 is a variable compression ratio engine with a change in compression ratio by modifying the dead volume of the combustion chamber at the top dead center of the piston by modifying the final position of the piston. relative to the breech.
  • This engine is associated with a computer (not shown), said engine calculator, containing engine operation maps according to various parameters, such as the engine speed or load, to determine the appropriate compression ratio, and fuel injection management means according to the compression ratio with which the engine is operating.
  • the computer controls the variation device of the compression ratio so that the piston is in PMH Tm ax-
  • the computer controls the fuel injection parameters so that the fuel jets 36 are sent into the mixing zone Z1 of the combustion chamber.
  • the fuel jets of the web 34 directly target the torus 60 by performing a path according to the arrow F1 for a better air / fuel mixture and allowing almost complete combustion in this torus.
  • the computer controls the variation device of the compression ratio so that the piston is in PMH Tm ini (FIG. 2).
  • the computer controls the fuel injection parameters so as to control the introduction of the jets of fuel 36 in the mixing zone Z2 of the combustion chamber so that they come to impact the concave surface 62 and develops along the arrow F2.
  • this injection can be performed in such a way that the fuel jets impinge on the outer edge of the projection 59 closest to the stud.
  • the fuel jets separate into two streams of fuel, one of the streams being introduced into the zone Z1 and the other flows in the zone Z2, as illustrated by the arrows F1 and F2 of Figure 2 , so that the combustion takes place in these two zones.
  • FIG. 3 illustrates, on a larger scale and without limitation, a portion of the bowl profile described above.
  • the bowl includes:
  • a bowl diameter BD with a radius considered near the bottom of the bowl and corresponding to a distance taken between the axis XX and the point furthest from the concave surface 56 by contributing to this axis
  • the dimensions of the bowl may satisfy at least one of the following conditions:
  • the ratio BD / L is substantially between 1, 3 and 1, 8,
  • the ratio GD / BD is substantially between 0.9 and 0.95 for the aerodynamics of the torus and the recovery of the fuel jets
  • the ratio H / L is substantially less than 0.6 and substantially greater than 0.5 to minimize the volume of oxidant between the nose of the injector and the nipple,
  • the ratio L / L1 is substantially between 1, 15 and 1, 7
  • the ratio R2 / R is substantially between 0.25 and 1,
  • the ratio GD / ID is substantially between 0.65 and 0.9
  • A3 is substantially between 50 and 70 °
  • the bowl diameter BD is smaller than the inflection diameter high ID2.
  • the combustion of the fuel / oxidant mixture for the maximum compression ratio takes place essentially in the volume of the torus while the combustion of the fuel / oxidant mixture for the minimum compression ratio takes place essentially in the upper zone and above the piston, and preferably in the volume of the torus as well as in the upper zone and above the piston.

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  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Dispersion Chemistry (AREA)
  • Combustion Methods Of Internal-Combustion Engines (AREA)
  • Output Control And Ontrol Of Special Type Engine (AREA)

Abstract

Variable compression ratio direct-injection internal combustion engine comprising at least one cylinder (10), a cylinder head (12) bearing a fuel injection means (14) spraying fuel in a single layer (34) of fuel jets (36), a piston (16) sliding in this cylinder, and a combustion chamber (32) delimited on one side by the top face (42) of the piston comprising a pip (46) rising up toward the cylinder head and arranged at the centre of a concave bowl (44). According to the invention, the combustion chamber comprises at least two mixing zones (Z1, Z2) into which the fuel jets (36) are injected, one of the zones (Z1) being used for a maximum compression ratio (Tmax) and the other (Z2) of the zones being used for a minimum compression ratio (Tmin).

Description

Moteur à combustion interne à taux de compression variable avec deux zones de mélange, notamment pour véhicule automobile et procédé d'injection pour un tel moteur. La présente invention se rapporte à un moteur à combustion interne à injection directe de carburant avec taux de compression variable, notamment pour véhicule automobile, et à un procédé d'injection pour un tel moteur.  Internal combustion engine with variable compression ratio with two mixing zones, especially for a motor vehicle and injection method for such an engine. The present invention relates to an internal combustion engine with direct injection of fuel with variable compression ratio, in particular for a motor vehicle, and to an injection method for such an engine.
Les systèmes de combustion des moteurs à combustion interne doivent répondre aux demandes de réduction des émissions de polluants, d'augmentation du couple et de la puissance spécifique ainsi que de la réduction du bruit de combustion, tout en restant compatibles avec les critères de tenue en endurance. The combustion systems of internal combustion engines must meet the demands of reducing pollutant emissions, increasing torque and specific power, and reducing combustion noise, while remaining compatible with the performance criteria. endurance.
Pour pouvoir répondre à cette demande, il est possible de modifier le taux de compression du moteur à combustion en fonction de la demande de puissance. To meet this demand, it is possible to change the compression ratio of the combustion engine according to the power demand.
Comme cela est généralement admis, le taux de compression d'un moteur est le rapport entre le volume de la chambre de combustion lorsque le piston est en position de point mort bas et le volume de cette chambre lorsqu'il est en position de point mort haut, dit volume mort. As is generally accepted, the compression ratio of an engine is the ratio between the volume of the combustion chamber when the piston is in the bottom dead center position and the volume of this chamber when in the neutral position. high, says dead volume.
De nombreux dispositifs permettent de modifier la position spatiale du piston dans le cylindre. Numerous devices make it possible to modify the spatial position of the piston in the cylinder.
Plus particulièrement, certains de ces dispositifs offrent la possibilité de changer le taux de compression de ce moteur en modifiant le volume mort de la chambre de combustion au point mort haut du piston. Pour cela, il suffit de modifier la position finale du piston par rapport à la culasse lorsqu'il est à son point mort haut.  More particularly, some of these devices offer the possibility of changing the compression ratio of this engine by changing the dead volume of the combustion chamber at the top dead center of the piston. For this, simply change the final position of the piston relative to the cylinder head when it is at its top dead center.
Ainsi pour un taux de compression minimal (volume mort maximal), la distance entre le haut du piston et la culasse est plus grande que celle relative à un taux de compression maximal (volume mort minimal). Cependant de tels moteurs avec taux de compression variable (VCR en anglais pour "Variable Compression Ratio") présentent des inconvénients non négligeables. En effet comme mieux décrit dans la demande FR 2 891 867, ce type de moteur comprend généralement un cylindre, un piston comprenant un téton disposé dans un bol concave et coulissant dans ce cylindre en un mouvement rectiligne alternatif, des moyens d'admission d'un comburant, des moyens d'échappement de gaz brûlés, des moyens pour faire varier la position du point mort haut du piston, et des moyens d'injection pour injecter un carburant dans la chambre de combustion de ce moteur. Thus for a minimum compression ratio (maximum dead volume), the distance between the top of the piston and the cylinder head is greater than that relative to a maximum compression ratio (minimum dead volume). However, such engines with variable compression ratio (VCR in English for "Variable Compression Ratio") have significant disadvantages. Indeed, as better described in the application FR 2 891 867, this type of engine generally comprises a cylinder, a piston comprising a pin disposed in a concave bowl and sliding in this cylinder in a reciprocating rectilinear movement, admission means of an oxidizer, means for exhausting burnt gases, means for varying the position of the top dead center of the piston, and injection means for injecting a fuel into the combustion chamber of this engine.
Comme détaillé dans ce document de l'art antérieur, les moyens d'injection de carburant comprennent un injecteur avec deux rangées d'orifices d'injection superposées permettant d'injecter le carburant sous la forme d'une ou deux nappes de jets de carburant superposées. As detailed in this document of the prior art, the fuel injection means comprise an injector with two rows of superimposed injection ports for injecting the fuel in the form of one or two layers of fuel jets. superimposed.
Ainsi, pour un taux de compression élevé, le carburant est injecté selon une seule nappe de jets et, pour un taux de compression faible, le carburant est injecté selon les deux angles de nappes.  Thus, for a high compression ratio, the fuel is injected in a single layer of jets and, for a low compression ratio, the fuel is injected at the two ply angles.
Ce type de moteur nécessite donc un injecteur multi nappes de carburant qui est d'élaboration complexe et qui doit obligatoirement être associé avec un dispositif de contrôle sophistiqué pour rendre opérationnel l'une et/ou l'autre nappe de jets de carburant. This type of engine therefore requires a multi-layer fuel injector which is complex in design and must necessarily be associated with a sophisticated control device to make operational one and / or the other ply of fuel jets.
De plus, ce type de moteur avec taux de compression variable par une variation de la distance piston/culasse a un inconvénient géométrique majeur.  In addition, this type of engine with variable compression ratio by a variation of the piston / cylinder head distance has a major geometric disadvantage.
En effet, par la modification de la distance piston/culasse, le positionnement relatif de l'injecteur et des jets de carburant est modifié par rapport au bol du piston.  Indeed, by changing the piston / cylinder head distance, the relative positioning of the injector and fuel jets is changed relative to the piston bowl.
De ce fait, on modifie donc profondément la répartition du carburant dans la chambre ainsi que tout le processus de combustion puisqu'un bol n'est généralement optimisé que pour des conditions géométriques « fixes », c'est-à- dire avec une position fixe du piston au point mort haut. Ainsi, pour optimiser un tel moteur à taux de compression variable, il est nécessaire de redéfinir une forme de bol de piston qui puisse être totalement insensible à la position relative de l'injecteur, ou tout du moins efficace quelle que soit cette position de l'injecteur. As a result, the distribution of the fuel in the chamber and the entire combustion process are substantially altered since a bowl is generally only optimized for "fixed" geometrical conditions, ie with a position fixed piston at the top dead center. Thus, to optimize such a variable compression ratio engine, it is necessary to redefine a piston bolt shape that can be totally insensitive to the relative position of the injector, or at least effective regardless of this position of the piston. 'injector.
La présente invention se propose de remédier à ces inconvénients avec un moteur qui comprend un injecteur conventionnel avec une seule nappe de jets de carburant qui injecte le carburant dans des zones de mélanges et de combustion de la chambre de combustion et cela quel que soit le taux de compression utilisé pour le moteur. The present invention proposes to remedy these drawbacks with a motor which comprises a conventional injector with a single ply of fuel jets which injects the fuel into combustion and combustion zones of the combustion chamber, whatever the rate compressor used for the engine.
A cet effet, la présente invention concerne un moteur à combustion interne à injection directe à taux de compression variable comprenant au moins un cylindre, une culasse portant un moyen d'injection de carburant projetant du carburant selon une seule nappe de jets de carburant, un piston coulissant dans ce cylindre, et une chambre de combustion délimitée sur un côté par la face supérieure du piston comportant un téton s'érigeant en direction de la culasse et disposé au centre d'un bol concave, caractérisé en ce que la chambre de combustion comprend au moins deux zones de mélange dans lesquelles sont injectés les jets de carburant, l'une des zones étant utilisée pour un taux de compression maximal et l'autre des zones étant utilisée pour un taux de compression minimal. For this purpose, the present invention relates to a variable compression ratio direct injection internal combustion engine comprising at least one cylinder, a cylinder head carrying a fuel injection means projecting fuel in a single layer of fuel jets, a sliding piston in this cylinder, and a combustion chamber delimited on one side by the upper face of the piston having a pin extending towards the cylinder head and disposed in the center of a concave bowl, characterized in that the combustion chamber comprises at least two mixing zones in which the fuel jets are injected, one of the zones being used for a maximum compression ratio and the other of the zones being used for a minimum compression ratio.
L'une des zones peut être associée à l'autre des zones pour le taux de compression minimal. One of the zones may be associated with the other zones for the minimum compression ratio.
Les zones de mélange peuvent être situées axialement l'une au-dessus de l'autre. The mixing zones can be located axially one above the other.
Les zones de mélange peuvent être délimitées l'une de l'autre par une saillie radiale. The mixing zones may be delimited from one another by a radial projection.
L'une des zones de mélange peut comprendre une surface concave raccordée à une surface convexe pour former la partie basse d'un volume torique. L'autre des zones de mélange peut comprendre une surface concave raccordée à une surface convexe pour former une barrière. One of the mixing zones may include a concave surface connected to a convex surface to form the bottom portion of a toric volume. The other of the mixing zones may comprise a concave surface connected to a convex surface to form a barrier.
Le moteur peut comprendre un piston avec un bol qui comporte un diamètre de bol BD, un diamètre de col GD, un diamètre d'inflexion bas ID1 , un diamètre d'inflexion haut ID2, une hauteur H de téton, une hauteur L du bol, une hauteur L1 du diamètre d'inflexion ID1 , un angle d'inclinaison a3, un rayon R pour la surface arrondie concave du tore et un rayon R2 pour la surface arrondie concave, les dimensions du bol pouvant satisfaire à au moins l'une des conditions suivantes : The engine may comprise a piston with a bowl which has a bowl diameter BD, a neck diameter GD, a low bend diameter ID1, a top bend diameter ID2, a height H of teat, a height L of the bowl , a height L1 of the inflection diameter ID1, an inclination angle a3, a radius R for the rounded concave surface of the torus and a radius R2 for the concave rounded surface, the dimensions of the bowl being able to satisfy at least one of following conditions:
· le rapport BD/L est sensiblement compris entre 1 ,3 et 1 ,8,  The ratio BD / L is substantially between 1, 3 and 1, 8,
• le rapport GD/BD est sensiblement compris entre 0,9 et 0,95 pour l'aérodynamique du tore et la remontée des jets de carburant, The ratio GD / BD is substantially between 0.9 and 0.95 for the aerodynamics of the torus and the recovery of the fuel jets,
• le rapport H/L est sensiblement inférieur à 0,6 et sensiblement supérieur à 0,5 pour minimiser le volume de comburant entre le nez de l'injecteur et le téton, The ratio H / L is substantially less than 0.6 and substantially greater than 0.5 to minimize the volume of oxidant between the nose of the injector and the nipple,
• le rapport L/L1 est sensiblement compris entre 1 , 15 et 1 ,7  The ratio L / L1 is substantially between 1, 15 and 1, 7
• le rapport R2/R est sensiblement compris entre 0,25 et 1 ,  The ratio R2 / R is substantially between 0.25 and 1,
• le rapport GD/ID est sensiblement compris entre 0,65 et 0,9, The ratio GD / ID is substantially between 0.65 and 0.9,
• a3 est sensiblement compris entre 50 et 70°, A3 is substantially between 50 and 70 °,
· le diamètre de bol BD est plus petit que le diamètre ID2.  · BD bowl diameter is smaller than ID2 diameter.
L'invention concerne également un procédé d'injection de carburant pour un moteur à combustion interne à injection directe à taux de compression variable comprenant au moins un cylindre, une culasse portant un moyen d'injection de carburant projetant du carburant selon une seule nappe de jets de carburant, un piston coulissant dans ce cylindre, et une chambre de combustion délimitée sur un côté par la face supérieure du piston comportant un téton s'érigeant en direction de la culasse et disposé au centre d'un bol concave, caractérisé en ce que, pour un taux de compression maximal, on injecte le carburant dans une zone de mélange de la chambre de combustion et, pour un taux de compression minimal, on injecte le carburant dans une autre zone de mélange de ladite chambre de combustion. Pour le taux de compression minimal, on peut injecter le carburant dans les deux zones de mélange. The invention also relates to a fuel injection method for a variable compression ratio direct injection internal combustion engine comprising at least one cylinder, a cylinder head carrying a fuel injection means throwing fuel in a single layer of fuel. jets of fuel, a piston sliding in this cylinder, and a combustion chamber delimited on one side by the upper face of the piston having a pin extending in the direction of the cylinder head and disposed in the center of a concave bowl, characterized in that that, for a maximum compression ratio, the fuel is injected into a mixing zone of the combustion chamber and, for a minimum compression ratio, the fuel is injected into another mixing zone of said combustion chamber. For the minimum compression ratio, the fuel can be injected into the two mixing zones.
Les autres caractéristiques et avantages de l'invention vont apparaître maintenant à la lecture de la description qui va suivre, donnée à titre uniquement illustratif et non limitatif, et à laquelle sont annexées : The other features and advantages of the invention will now appear on reading the following description, given solely by way of illustration and not limitation, and to which are appended:
- la figure 1 qui montre un moteur à combustion interne avec un taux de compression variable selon l'invention, dans une configuration pour un taux de compression,  FIG. 1, which shows an internal combustion engine with a variable compression ratio according to the invention, in a configuration for a compression ratio,
- la figure 2 qui est une autre vue du moteur de la figure 1 pour un autre taux de compression, et  FIG. 2 which is another view of the engine of FIG. 1 for another compression ratio, and
- la figure 3 qui est une vue locale partielle à grande échelle du profil du bol des figures 1 et 2. Les figures 1 et 2 illustrent, de manière non limitative, un moteur à combustion interne avec taux de compression variable et à injection directe de carburant.  FIG. 3 which is a partial large-scale local view of the profile of the bowl of FIGS. 1 and 2. FIGS. 1 and 2 illustrate, in a nonlimiting manner, an internal combustion engine with variable compression ratio and with direct injection of fuel.
Ce moteur est avantageusement un moteur à allumage par compression utilisant un carburant de type Diesel.  This engine is advantageously a compression ignition engine using a diesel type fuel.
Bien entendu tout autre carburant ayant les caractéristiques physicochimiques permettant le fonctionnement d'un moteur de type allumage par compression incluant un système d'injection directe peut être utilisé, comme du kérosène. Ce moteur comprend au moins un cylindre 10, une culasse 12 fermant le cylindre en partie haute, des moyens d'injection de carburant 14 portés par la culasse et un piston 1 6 d'axe XX coulissant dans le cylindre en un mouvement rectiligne alternatif.  Of course, any other fuel having the physicochemical characteristics allowing the operation of a compression ignition type engine including a direct injection system can be used, such as kerosene. This engine comprises at least one cylinder 10, a cylinder head 12 closing the cylinder in the upper part, fuel injection means 14 carried by the cylinder head and a piston 1 6 XX axis sliding in the cylinder in a reciprocating rectilinear motion.
Ce moteur comprend également un moyen d'échappement 18 des gaz brûlés avec au moins une tubulure d'échappement 20 dont l'ouverture peut être contrôlée par tous moyens, comme par exemple une soupape d'échappement 22 et un moyen d'admission 24 d'un comburant avec au moins une tubulure d'admission 26 dont l'ouverture peut être contrôlée par tous moyens, comme par exemple une soupape d'admission 28. Par le terme comburant, il est compris de l'air à pression ambiante ou de l'air suralimenté ou encore un mélange d'air (suralimenté ou non) avec des gaz brûlés. Les moyens d'injection comprennent un injecteur de carburant 30, de préférence disposé dans l'axe XX du piston, dont le nez comporte une multiplicité d'orifices au travers desquels le carburant est pulvérisé et projeté en direction de la chambre de combustion 32 du moteur. C'est à partir de cet injecteur que le carburant projeté forme une seule nappeThis engine also comprises a flue exhaust means 18 with at least one exhaust pipe 20 whose opening can be controlled by any means, such as for example an exhaust valve 22 and an intake means 24. an oxidizer with at least one intake manifold 26 whose opening can be controlled by any means, such as an intake valve 28. By the term oxidizer, it includes air at ambient pressure or supercharged air or a mixture of air (supercharged or not) with flue gas. The injection means comprise a fuel injector 30, preferably arranged in the axis XX of the piston, whose nose comprises a multiplicity of orifices through which the fuel is sprayed and projected towards the combustion chamber 32 of the piston. engine. It is from this injector that the projected fuel forms a single layer
34 de jets de carburant 36 d'angle de nappe A1 qui, dans l'exemple montré, a un axe général confondu avec celui du piston XX. 34 of fuel jets 36 of lap angle A1 which, in the example shown, has a general axis coincides with that of the piston XX.
Par angle de nappe, il est entendu l'angle au sommet que forme le cône de jets issu de l'injecteur et dont la paroi périphérique fictive passe par tous les axes 38 des jets de carburant 36.  By nappe angle, it is understood the angle at the top that forms the cone of jets coming from the injector and whose imaginary peripheral wall passes through all the axes 38 of the fuel jets 36.
La chambre de combustion 32 est délimitée par la face interne de la culasse 40 en vis à vis du piston, la paroi interne circulaire 41 du cylindre 10 et la face supérieure 42 du piston 1 6. The combustion chamber 32 is delimited by the internal face of the cylinder head 40 opposite the piston, the circular inner wall 41 of the cylinder 10 and the upper face 42 of the piston 1 6.
Cette face supérieure du piston comporte un bol concave 44, ici d'axe confondu avec celui du cylindre, dont la concavité est tournée vers la culasse et qui loge un téton 46 situé sensiblement au centre du bol, qui s'élève vers la culasse 12, en étant de préférence coaxial avec l'axe de la nappe de jets de carburant.  This upper face of the piston comprises a concave bowl 44, here of axis coincident with that of the cylinder, whose concavity is turned towards the cylinder head and which houses a pin 46 located substantially in the center of the bowl, which rises towards the cylinder head 12 , preferably being coaxial with the axis of the fuel jet web.
Comme mieux illustré sur les figures, le téton 46, de forme générale tronconique, comporte un sommet 48 de préférence arrondi, se poursuivant, en s'écartant symétriquement de l'axe XX vers l'extérieur du piston, par une surface inclinée 50 sensiblement rectiligne pour arriver à un fond 52 du bol. As best illustrated in the figures, the stud 46, of generally frustoconical shape, has an apex 48 preferably rounded, continuing, deviating symmetrically from the axis XX towards the outside of the piston, by an inclined surface 50 substantially rectilinear to arrive at a bottom 52 of the bowl.
Dans l'exemple des figures, le fond de ce bol est arrondi avec une surface arrondie concave 54 en arc de cercle, dite surface arrondie interne, raccordée au bas du flanc incliné et une autre surface arrondie concave 56 en arc de cercle, dite surface arrondie externe, raccordée par une de ses extrémités à l'extrémité basse de la surface arrondie interne et par l'autre de ses extrémités à une paroi latérale 58, ici sensiblement arrondie en direction de l'axe XX, en formant ainsi une saillie radiale 59 en direction du téton. In the example of the figures, the bottom of this bowl is rounded with a curved rounded concave surface 54, called the inner rounded surface, connected to the bottom of the inclined sidewall and another concave rounded surface 56 in an arc of a circle, said surface outer rounded, connected at one end to the low end of the inner rounded surface and the other of its ends to a side wall 58, here substantially rounded towards the axis XX, thereby forming a radial projection 59 in the direction of the stud.
Les deux surfaces arrondies 54 et 56 délimitent ainsi la partie basse d'un volume torique 60 (ou tore) délimité en partie haute par la saille 59.  The two rounded surfaces 54 and 56 thus delimit the lower part of a toric volume 60 (or torus) delimited at the top by the seam 59.
La paroi latérale arrondie 58 se poursuit, toujours en s'écartant de l'axe XX, par une surface arrondie concave 62 qui se continue par une surface convexe externe 64 qui arrive à une surface plane 66 s'avançant jusqu'au voisinage de la paroi 41 du cylindre. Les surfaces 62 et 64 formant alors une barrière 67 dont le rôle sera explicité dans la suite de la description.  The rounded side wall 58 continues, always away from the axis XX, by a concave rounded surface 62 which is continued by an outer convex surface 64 which arrives at a flat surface 66 advancing to the vicinity of the wall 41 of the cylinder. The surfaces 62 and 64 then forming a barrier 67 whose role will be explained in the following description.
La chambre de combustion comprend ainsi deux zones distinctes Z1 et Z2 qui assurent le mélange entre le comburant qu'elles contiennent (air [suralimenté ou non] ou mélange d'air et de gaz brûlés recirculés) et le carburant provenant de l'injecteur, ainsi que la combustion du mélange carburé ainsi formé lorsque les conditions physico-chimiques de ce mélange sont assurées pour assurer une telle combustion. The combustion chamber thus comprises two distinct zones Z1 and Z2 which ensure the mixing between the oxidant they contain (air [supercharged or not] or mixture of air and recirculated flue gas) and the fuel coming from the injector, as well as the combustion of the carbureted mixture thus formed when the physicochemical conditions of this mixture are ensured to ensure such combustion.
La zone Z1 , qui est délimitée par le téton 46, le tore 60 du fond du bol et la saillie radiale 59, forme la zone basse de la chambre de combustion. La zone Z2, qui est délimitée à partir de la saillie 59 par la surface concave 62, la surface convexe 64, la surface plane 66, la paroi interne périphérique du cylindre et la face interne 40 de la culasse 12 constitue la zone haute de cette chambre qui est placée au-dessus de la zone basse. The zone Z1, which is delimited by the pin 46, the torus 60 of the bottom of the bowl and the radial projection 59, forms the lower zone of the combustion chamber. The zone Z2, which is delimited from the projection 59 by the concave surface 62, the convex surface 64, the flat surface 66, the peripheral inner wall of the cylinder and the inner face 40 of the cylinder head 12 constitutes the upper zone of this zone. room that is placed above the low area.
Comme mentionné plus haut, le moteur des figures 1 et 2 est un moteur à taux de compression variable avec un changement de taux de compression par modification du volume mort de la chambre de combustion au point mort haut du piston en modifiant la position finale du piston par rapport à la culasse. As mentioned above, the engine of FIGS. 1 and 2 is a variable compression ratio engine with a change in compression ratio by modifying the dead volume of the combustion chamber at the top dead center of the piston by modifying the final position of the piston. relative to the breech.
De nombreux dispositifs bien connus de l'homme du métier permettent d'arriver à un tel résultat, comme la mise en place d'un excentrique entre le maneton du vilebrequin et la tête de la bielle, tel que cela est mieux décrit dans le brevet français N° 2 801 932. Ainsi, pour un taux de compression maximal Tmax avec un volume mort minimal (figure 1 ), le piston est au point mort haut (PMHTmax) avec une distance ÛTmax entre le haut du piston et la face 40 de la culasse. Pour un taux de compression minimal Tmini avec un volume mort maximal (figure 2), le piston est au point mort haut (PMHTmini) avec une distance DTmini, entre le haut du piston et la face 40 de la culasse, qui est plus grande que DTmax- Many devices well known to those skilled in the art can achieve such a result, such as the establishment of an eccentric between the crank pin and the head of the rod, as is better described in the patent French No. 2,801,932. Thus, for a maximum compression ratio Tmax with a minimum dead volume (FIG. 1), the piston is at the top dead center ( Tm ax) with a distance τTmax between the top of the piston and the face 40 of the cylinder head. For a minimum compression ratio Tmini with a maximum dead volume (FIG. 2), the piston is at the top dead center ( Tm ini) with a distance D Tm ini, between the top of the piston and the face 40 of the cylinder head, which is larger than D Tm ax-
Ce moteur est associé à un calculateur (non représenté), dit calculateur moteur, contenant des cartographies de fonctionnement du moteur en fonction de différents paramètres, tels que le régime ou la charge de ce moteur, pour déterminer le taux de compression adéquat, et des moyens de gestion de l'injection du carburant en fonction du taux de compression avec lequel le moteur est en fonctionnement. This engine is associated with a computer (not shown), said engine calculator, containing engine operation maps according to various parameters, such as the engine speed or load, to determine the appropriate compression ratio, and fuel injection management means according to the compression ratio with which the engine is operating.
En cas de fonctionnement du moteur avec un taux de compression maximal (figure 1 ), le calculateur contrôle le dispositif de variation du taux de compression de manière à ce que le piston se trouve en PMHTmax-In the case of engine operation with a maximum compression ratio (FIG. 1), the computer controls the variation device of the compression ratio so that the piston is in PMH Tm ax-
Pour cette position du piston, le calculateur contrôle les paramètres d'injection du carburant de façon à ce que les jets de carburant 36 soient envoyés dans la zone de mélange Z1 de la chambre de combustion. For this position of the piston, the computer controls the fuel injection parameters so that the fuel jets 36 are sent into the mixing zone Z1 of the combustion chamber.
Grâce à ce paramétrage, les jets de carburant de la nappe 34 ciblent directement le tore 60 en réalisant un cheminement selon la flèche F1 pour un meilleur mélange air/carburant et permettant une combustion quasiment complète dans ce tore.  With this parameterization, the fuel jets of the web 34 directly target the torus 60 by performing a path according to the arrow F1 for a better air / fuel mixture and allowing almost complete combustion in this torus.
De plus, grâce à la présence de la saillie radiale 59, le carburant ne peut remonter dans la partie haute du piston et la combustion se produit pour l'essentiel dans la zone Z1 . Pour un taux de compression minimal (figure 2), le calculateur contrôle le dispositif de variation du taux de compression de manière à ce que le piston se trouve en PMHTmini (figure 2). In addition, thanks to the presence of the radial projection 59, the fuel can not go up in the upper part of the piston and the combustion occurs essentially in the zone Z1. For a minimum compression ratio (FIG. 2), the computer controls the variation device of the compression ratio so that the piston is in PMH Tm ini (FIG. 2).
Pour cette position du piston, le calculateur contrôle les paramètres d'injection du carburant de façon à commander l'introduction des jets de carburant 36 dans la zone de mélange Z2 de la chambre de combustion pour qu'ils viennent impacter la surface concave 62 et se développe selon la flèche F2. For this position of the piston, the computer controls the fuel injection parameters so as to control the introduction of the jets of fuel 36 in the mixing zone Z2 of the combustion chamber so that they come to impact the concave surface 62 and develops along the arrow F2.
Par cela la combustion se réalise en partie haute de la chambre de combustion et les surfaces 62 et 64 forment une barrière qui empêche la dispersion du carburant vers la paroi interne 41 du cylindre, et permet ainsi de limiter le transfert de matière charbonneuse résultant de la combustion dans l'huile recouvrant la paroi 41 . De manière préférentielle, pour le taux de compression minimal, cette injection peut être réalisée d'une telle manière que les jets de carburant viennent impacter le bord externe de la saillie 59 la plus proche du téton. Suite à cela, les jets de carburant se séparent en deux flux de carburant, l'un des flux étant introduit dans la zone Z1 et l'autre des flux dans la zone Z2, comme illustré par les flèches F1 et F2 de la figure 2, pour que la combustion se réalise dans ces deux zones.  By this combustion is carried out in the upper part of the combustion chamber and the surfaces 62 and 64 form a barrier which prevents the dispersion of the fuel towards the inner wall 41 of the cylinder, and thus makes it possible to limit the transfer of carbonaceous material resulting from the burning in oil covering the wall 41. Preferably, for the minimum compression ratio, this injection can be performed in such a way that the fuel jets impinge on the outer edge of the projection 59 closest to the stud. Following this, the fuel jets separate into two streams of fuel, one of the streams being introduced into the zone Z1 and the other flows in the zone Z2, as illustrated by the arrows F1 and F2 of Figure 2 , so that the combustion takes place in these two zones.
On se réfère maintenant à la figure 3 qui illustre, à plus grande échelle et de manière non limitative, une partie du profil du bol décrit plus haut. Referring now to Figure 3 which illustrates, on a larger scale and without limitation, a portion of the bowl profile described above.
Dans cette configuration, le bol comprend : In this configuration, the bowl includes:
- un diamètre de bol BD avec un rayon considéré au voisinage du fond du bol et correspondant à une distance prise entre l'axe XX et le point le plus éloigné de la surface concave 56 par apport à cet axe,  a bowl diameter BD with a radius considered near the bottom of the bowl and corresponding to a distance taken between the axis XX and the point furthest from the concave surface 56 by contributing to this axis,
- un diamètre de col GD avec un rayon qui correspond à la distance entre l'axe XX et l'extrémité de saillie radiale 59 la proche du téton et qui délimite ainsi la section de sortie de la zone Z1 de ce bol,  a neck diameter GD with a radius which corresponds to the distance between the axis XX and the radial projection end 59 near the stud and which thus delimits the outlet section of the zone Z1 of this bowl,
- un diamètre d'inflexion bas ID1 avec un rayon qui correspond à la distance entre l'axe XX et le point d'inflexion entre la paroi 58 de la saillie 59 et la surface concave 62,  a low inflection diameter ID1 with a radius corresponding to the distance between the axis XX and the point of inflection between the wall 58 of the projection 59 and the concave surface 62,
- un diamètre d'inflexion haut ID2 avec un rayon qui correspond à la distance entre l'axe XX et le point d'inflexion entre la surface convexe 64 et la surface plane 66,  a high inflection diameter ID2 with a radius corresponding to the distance between the axis XX and the point of inflection between the convex surface 64 and the plane surface 66,
- une hauteur H de téton entre le fond du bol jusqu'au sommet du téton 46, - une hauteur L du bol entre le fond du bol jusqu'à la surface plane 66,a height H of stud between the bottom of the bowl to the top of the pin 46, a height L of the bowl between the bottom of the bowl and the flat surface 66,
- une hauteur L1 pour le diamètre ID1 considérée entre le point d'inflexion entre la paroi 58 de la saillie 59 et la surface concave 62 et le fond du bol, a height L1 for the ID1 diameter considered between the point of inflection between the wall 58 of the projection 59 and the concave surface 62 and the bottom of the bowl,
- un angle d'inclinaison a3, angle que fait la surface inclinée 50 du téton par rapport à une verticale,  an angle of inclination a3, an angle made by the inclined surface 50 of the stud relative to a vertical,
- un rayon R pour la surface arrondie concave 56 du tore 60,  a radius R for the concave rounded surface 56 of the torus 60,
- un rayon R2 pour la surface arrondie concave 62.  a radius R2 for the concave rounded surface 62.
Les dimensions du bol peuvent satisfaire à au moins l'une des conditions suivantes : The dimensions of the bowl may satisfy at least one of the following conditions:
• le rapport BD/L est sensiblement compris entre 1 ,3 et 1 ,8,  The ratio BD / L is substantially between 1, 3 and 1, 8,
• le rapport GD/BD est sensiblement compris entre 0,9 et 0,95 pour l'aérodynamique du tore et la remontée des jets de carburant, The ratio GD / BD is substantially between 0.9 and 0.95 for the aerodynamics of the torus and the recovery of the fuel jets,
• le rapport H/L est sensiblement inférieur à 0,6 et sensiblement supérieur à 0,5 pour minimiser le volume de comburant entre le nez de l'injecteur et le téton, The ratio H / L is substantially less than 0.6 and substantially greater than 0.5 to minimize the volume of oxidant between the nose of the injector and the nipple,
• le rapport L/L1 est sensiblement compris entre 1 , 15 et 1 ,7  The ratio L / L1 is substantially between 1, 15 and 1, 7
• le rapport R2/R est sensiblement compris entre 0,25 et 1 ,  The ratio R2 / R is substantially between 0.25 and 1,
• le rapport GD/ID est sensiblement compris entre 0,65 et 0,9, The ratio GD / ID is substantially between 0.65 and 0.9,
• a3 est sensiblement compris entre 50 et 70° A3 is substantially between 50 and 70 °
• le diamètre de bol BD est plus petit que le diamètre d'inflexion haut ID2.  • the bowl diameter BD is smaller than the inflection diameter high ID2.
Ainsi, grâce à ce paramétrage du bol, la combustion du mélange combustible/comburant pour le taux de compression maximal se déroule essentiellement dans le volume du tore alors que la combustion du mélange combustible/comburant pour le taux de compression minimal se déroule essentiellement dans la zone supérieure et au-dessus du piston, et préférentiellement dans le volume du tore ainsi que dans la zone supérieure et au-dessus du piston. Thus, thanks to this parameterization of the bowl, the combustion of the fuel / oxidant mixture for the maximum compression ratio takes place essentially in the volume of the torus while the combustion of the fuel / oxidant mixture for the minimum compression ratio takes place essentially in the upper zone and above the piston, and preferably in the volume of the torus as well as in the upper zone and above the piston.

Claims

REVENDICATIONS
1 ) Moteur à combustion interne à injection directe à taux de compression variable comprenant au moins un cylindre (10), une culasse (12) portant un moyen d'injection de carburant (14) projetant du carburant selon une nappe (34) de jets de carburant (36), un piston (1 6) coulissant dans ce cylindre, et une chambre de combustion (32) délimitée sur un côté par la face supérieure (42) du piston comportant un téton (46) s'érigeant en direction de la culasse et disposé au centre d'un bol concave (44), caractérisé en ce que la chambre de combustion comprend au moins deux zones de mélange (Z1 , Z2) dans lesquelles sont injectés les jets de carburant (36), l'une (Z1 ) des zones étant utilisée pour un taux de compression maximal (Tmax) et l'autre (Z2) des zones étant utilisée pour un taux de compression minimal (Tmini). 2) Moteur à combustion interne selon la revendication 1 , caractérisé en ce que l'une (Z1 ) des zones est associée à l'autre des zones (Z2) pour le taux de compression minimal (Tmini). 1) Direct injection internal combustion engine with a variable compression ratio comprising at least one cylinder (10), a cylinder head (12) carrying a fuel injection means (14) throwing fuel according to a ply (34) of jets fuel (36), a piston (1 6) sliding in this cylinder, and a combustion chamber (32) delimited on one side by the upper face (42) of the piston having a pin (46) erected in the direction of the cylinder head and arranged at the center of a concave bowl (44), characterized in that the combustion chamber comprises at least two mixing zones (Z1, Z2) into which the fuel jets (36) are injected, one (Z1) areas being used for a maximum compression ratio (Tmax) and the other (Z2) areas being used for a minimum compression ratio (Tmini). 2) Internal combustion engine according to claim 1, characterized in that one (Z1) of the zones is associated with the other of the zones (Z2) for the minimum compression ratio (Tmini).
3) Moteur à combustion interne selon la revendication 1 ou 2, caractérisé en ce que les zones de mélange (Z1 , Z2) sont situées axialement l'une au-dessus de l'autre. 3) Internal combustion engine according to claim 1 or 2, characterized in that the mixing zones (Z1, Z2) are located axially one above the other.
4) Moteur à combustion interne selon la revendication 3, caractérisé en ce que les zones de mélange (Z1 , Z2) sont délimitées l'une de l'autre par une saillie radiale (59). 4) Internal combustion engine according to claim 3, characterized in that the mixing zones (Z1, Z2) are delimited from one another by a radial projection (59).
5) Moteur à combustion interne selon l'une des revendications précédentes, caractérisé en ce que l'une (Z1 ) des zones de mélange comprend une surface concave (54) raccordée à une surface convexe (56) pour former la partie basse d'un volume torique (60). 5) Internal combustion engine according to one of the preceding claims, characterized in that one (Z1) of the mixing zones comprises a concave surface (54) connected to a convex surface (56) to form the lower part of a toric volume (60).
6) Moteur à combustion interne selon l'une des revendications précédentes, caractérisé en ce que l'autre (Z2) des zones de mélange comprend une surface concave (62) raccordée à une surface convexe (64) pour former une barrière (67). 7) Moteur selon l'une des revendication précédentes dans lequel le bol comprend un diamètre de bol BD, un diamètre de col GD, un diamètre d'inflexion bas ID1 , un diamètre d'inflexion haut ID2, une hauteur H de téton, une hauteur L du bol, une hauteur L1 du diamètre d'inflexion ID1 , un angle d'inclinaison a3, un rayon R pour la surface arrondie concave (56) du tore (60) et un rayon R2 pour la surface arrondie concave (62), caractérisé en ce que les dimensions du bol satisfont à au moins l'une des condition suivantes : 6) Internal combustion engine according to one of the preceding claims, characterized in that the other (Z2) mixing zones comprises a concave surface (62) connected to a convex surface (64) to form a barrier (67) . 7) Motor according to one of the preceding claim wherein the bowl comprises a bowl diameter BD, a neck diameter GD, a low inflection diameter ID1, a high inflection diameter ID2, a height H of pin, a height L of the bowl, a height L1 of the inflection diameter ID1, an inclination angle a3, a radius R for the concave rounded surface (56) of the torus (60) and a radius R2 for the concave rounded surface (62) characterized in that the dimensions of the bowl satisfy at least one of the following conditions:
• le rapport BD/L est sensiblement compris entre 1 ,3 et 1 ,8,  The ratio BD / L is substantially between 1, 3 and 1, 8,
« le rapport GD/BD est sensiblement compris entre 0,9 et 0,95 pour l'aérodynamique du tore et la remontée des jets de carburant, The ratio GD / BD is substantially between 0.9 and 0.95 for the torus aerodynamics and the rise of the fuel jets,
• le rapport H/L est sensiblement inférieur à 0,6 et sensiblement supérieur à 0,5 pour minimiser le volume de comburant entre le nez de l'injecteur et le téton, The ratio H / L is substantially less than 0.6 and substantially greater than 0.5 to minimize the volume of oxidant between the nose of the injector and the nipple,
« le rapport L/L1 est sensiblement compris entre 1 , 15 et 1 ,7  The ratio L / L1 is substantially between 1, 15 and 1, 7
• le rapport R2/R est sensiblement compris entre 0,25 et 1 ,  The ratio R2 / R is substantially between 0.25 and 1,
• le rapport GD/ID est sensiblement compris entre 0,65 et 0,9  • the ratio GD / ID is substantially between 0.65 and 0.9
• a3 est sensiblement compris entre 50 et 70°,  A3 is substantially between 50 and 70 °,
• le diamètre de bol BD est plus petit que le diamètre ID2.  • BD bowl diameter is smaller than ID2 diameter.
8) Procédé d'injection de carburant pour un moteur à combustion interne à injection directe à taux de compression variable comprenant au moins un cylindre (10), une culasse (12) portant un moyen d'injection de carburant (14) projetant du carburant selon une nappe (34) de jets de carburant (36), un piston (1 6) coulissant dans ce cylindre, et une chambre de combustion (32) délimitée sur un côté par la face supérieure (42) du piston comportant un téton (46) s'érigeant en direction de la culasse et disposé au centre d'un bol concave (44), caractérisé en ce que, pour un taux de compression maximal (Tmax), on injecte le carburant dans une zone de mélange (Z1 ) de la chambre de combustion et, pour un taux de compression minimal (Tmini), on injecte le carburant dans une autre zone de mélange (Z2) de ladite chambre de combustion. 9) Procédé d'injection selon la revendication 8, caractérisé en ce que, pour le taux de compression minimal (Tmini), on injecte le carburant dans les deux zones de mélange (Z1 , Z2). 8) Fuel injection method for a variable compression ratio direct injection internal combustion engine comprising at least one cylinder (10), a cylinder head (12) carrying a fuel injection means (14) throwing fuel according to a ply (34) of fuel jets (36), a piston (1 6) sliding in this cylinder, and a combustion chamber (32) delimited on one side by the upper face (42) of the piston comprising a stud ( 46) in the direction of the cylinder head and arranged in the center of a concave bowl (44), characterized in that, for a maximum compression ratio (Tmax), the fuel is injected into a mixing zone (Z1) of the combustion chamber and, for a minimum compression ratio (Tmini), the fuel is injected into another mixing zone (Z2) of said combustion chamber. 9) Injection method according to claim 8, characterized in that, for the minimum compression ratio (Tmini), the fuel is injected into the two mixing zones (Z1, Z2).
EP17700172.4A 2016-01-26 2017-01-09 Variable compression ratio internal combustion engine with two mixing zones, notably for a motor vehicle, and method of injection for such a vehicle Withdrawn EP3408513A1 (en)

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FR1650592A FR3047043B1 (en) 2016-01-26 2016-01-26 INTERNAL COMBUSTION ENGINE WITH VARIABLE COMPRESSION RATE WITH TWO MIXING ZONES, ESPECIALLY FOR A MOTOR VEHICLE AND INJECTION METHOD FOR SUCH AN ENGINE.
PCT/EP2017/050328 WO2017129386A1 (en) 2016-01-26 2017-01-09 Variable compression ratio internal combustion engine with two mixing zones, notably for a motor vehicle, and method of injection for such a vehicle

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Families Citing this family (9)

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Publication number Priority date Publication date Assignee Title
CN108252794A (en) * 2018-02-09 2018-07-06 中国第汽车股份有限公司 A kind of natural gas engine special-shaped surfaces combustion chamber
JP7155679B2 (en) * 2018-07-06 2022-10-19 マツダ株式会社 Diesel engine fuel injection controller
JP7124733B2 (en) * 2019-01-29 2022-08-24 マツダ株式会社 Compression ignition engine controller
JP7124731B2 (en) * 2019-01-29 2022-08-24 マツダ株式会社 Compression ignition engine controller
JP2021011843A (en) * 2019-07-05 2021-02-04 三菱重工エンジン＆ターボチャージャ株式会社 Piston of internal combustion engine and internal combustion engine
CN111022210B (en) * 2019-11-13 2021-08-03 哈尔滨工业大学（威海） High-turbulence piston combustion chamber for diesel oil and natural gas dual fuel
JP2021181765A (en) * 2020-05-19 2021-11-25 株式会社小松製作所 Piston for diesel engine and diesel engine
CN114412652B (en) * 2022-03-29 2022-06-24 潍柴动力股份有限公司 Engine combustion system control method and engine combustion system
CN115853632B (en) * 2023-02-27 2023-06-23 潍柴动力股份有限公司 Combustion chamber and gas engine

Family Cites Families (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2801932B1 (en) 1999-11-10 2002-02-15 Michel Alain Leon Marchisseau METHOD AND DEVICE FOR MODIFYING AND TAKING ACCOUNT OF THE COMPRESSION RATE TO OPTIMIZE THE OPERATION OF RECIPROCATING PISTON ENGINES
US6752105B2 (en) * 2002-08-09 2004-06-22 The United States Of America As Represented By The Administrator Of The United States Environmental Protection Agency Piston-in-piston variable compression ratio engine
CN100398793C (en) * 2003-04-16 2008-07-02 韦斯特波特动力股份有限公司 Internal combustion engine with injection of gaseous fuel
CN100476180C (en) * 2003-10-09 2009-04-08 Avl里斯脱有限公司 Method for operating an internal combustion engine
FR2891867B1 (en) * 2005-10-10 2012-04-20 Peugeot Citroen Automobiles Sa DIRECT INJECTION DIESEL ENGINE WITH VARIABLE COMPRESSION VOLUMETRIC RATIO
BE1016961A3 (en) * 2006-01-23 2007-11-06 Avermaete Gilbert IMPROVEMENTS IN THE ENGINE WITH VARIABLE VOLUMETRIC RATIO.
JP2008309024A (en) * 2007-06-13 2008-12-25 Toyota Motor Corp Variable compression ratio internal combustion engine
KR101262577B1 (en) * 2011-07-18 2013-05-08 현대자동차주식회사 Diesel Engine Piston
FR3012522B1 (en) * 2013-10-25 2018-08-24 IFP Energies Nouvelles COMBUSTION ENGINE WITH DIRECT INJECTION OF COMPRESSION IGNITION FUEL AND FUEL INJECTION METHOD FOR SUCH ENGINE.
FR3017421B1 (en) * 2014-02-10 2018-03-16 IFP Energies Nouvelles INTERNAL COMBUSTION ENGINE WITH INJECTION OF TWO DIFFERENTIATED FLOW FUEL TANKS AND FUEL INJECTION METHOD FOR SUCH A MOTOR.
FR3018550B1 (en) * 2014-03-14 2019-04-12 IFP Energies Nouvelles METHOD FOR CONTROLLING FUEL INJECTION OF AN INTERNAL COMBUSTION ENGINE WITH DIRECT INJECTION, ESPECIALLY COMPRESSION IGNITION, AND ENGINE USING SUCH A METHOD

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