EP3025038A1 - Method for controlling a two-stroke internal combustion engine - Google Patents

Method for controlling a two-stroke internal combustion engine

Info

Publication number
EP3025038A1
EP3025038A1 EP14755865.4A EP14755865A EP3025038A1 EP 3025038 A1 EP3025038 A1 EP 3025038A1 EP 14755865 A EP14755865 A EP 14755865A EP 3025038 A1 EP3025038 A1 EP 3025038A1
Authority
EP
European Patent Office
Prior art keywords
pressure
engine
intake air
piston
cylinder
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Withdrawn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
EP14755865.4A
Other languages
German (de)
French (fr)
Inventor
Guillaume LABEDAN
Hugues Denis JOUBERT
Norbert Lartigue
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.)
Societe Motorisations Aeronautiques SA
Original Assignee
Societe Motorisations Aeronautiques SA
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 Societe Motorisations Aeronautiques SA filed Critical Societe Motorisations Aeronautiques SA
Publication of EP3025038A1 publication Critical patent/EP3025038A1/en
Withdrawn legal-status Critical Current

Links

Classifications

    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02BINTERNAL-COMBUSTION PISTON ENGINES; COMBUSTION ENGINES IN GENERAL
    • F02B25/00Engines characterised by using fresh charge for scavenging cylinders
    • F02B25/20Means for reducing the mixing of charge and combustion residues or for preventing escape of fresh charge through outlet ports not provided for in, or of interest apart from, subgroups F02B25/02 - F02B25/18
    • F02B25/22Means for reducing the mixing of charge and combustion residues or for preventing escape of fresh charge through outlet ports not provided for in, or of interest apart from, subgroups F02B25/02 - F02B25/18 by forming air cushion between charge and combustion residues
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02BINTERNAL-COMBUSTION PISTON ENGINES; COMBUSTION ENGINES IN GENERAL
    • F02B25/00Engines characterised by using fresh charge for scavenging cylinders
    • F02B25/02Engines characterised by using fresh charge for scavenging cylinders using unidirectional scavenging
    • F02B25/04Engines having ports both in cylinder head and in cylinder wall near bottom of piston stroke
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02BINTERNAL-COMBUSTION PISTON ENGINES; COMBUSTION ENGINES IN GENERAL
    • F02B25/00Engines characterised by using fresh charge for scavenging cylinders
    • F02B25/20Means for reducing the mixing of charge and combustion residues or for preventing escape of fresh charge through outlet ports not provided for in, or of interest apart from, subgroups F02B25/02 - F02B25/18
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02BINTERNAL-COMBUSTION PISTON ENGINES; COMBUSTION ENGINES IN GENERAL
    • F02B75/00Other engines
    • F02B75/02Engines characterised by their cycles, e.g. six-stroke
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02BINTERNAL-COMBUSTION PISTON ENGINES; COMBUSTION ENGINES IN GENERAL
    • F02B75/00Other engines
    • F02B75/02Engines characterised by their cycles, e.g. six-stroke
    • F02B2075/022Engines characterised by their cycles, e.g. six-stroke having less than six strokes per cycle
    • F02B2075/025Engines characterised by their cycles, e.g. six-stroke having less than six strokes per cycle two

Definitions

  • the present invention relates to a control method of a two-stroke internal combustion engine and a two-stroke internal combustion engine to be controlled according to the control method according to the invention.
  • a control method of a two-stroke internal combustion engine and a two-stroke internal combustion engine to be controlled according to the control method according to the invention.
  • Such a motor and such a control method can be advantageously implemented in the aeronautical field.
  • An exhaust port located at one end of the engine cylinder for exhausting the flue gases
  • Such an internal combustion two-stroke engine is characterized by a driving time for each crankshaft revolution.
  • the piston contained in the engine only contributes to the compression and expansion of the gases contained in the engine cylinder, the evacuation of the burnt gases and the filling of the engine cylinder in air being achieved by other mechanisms. More particularly, a source of compressed air at the bottom dead center of the engine ensures the air filling of the engine cylinder by simultaneously pushing the flue gases towards the exhaust port. The opening of the exhaust port allows the evacuation of burnt gases.
  • the invention therefore aims to overcome the disadvantages of the state of the art.
  • the present invention aims to provide a method for controlling an internal combustion two-stroke engine having an optimized combustion efficiency.
  • the invention relates to a method for controlling an internal combustion two-stroke engine, said engine comprising:
  • said driving method comprising the following steps:
  • a stratification layer is understood to mean a layer of air admitted into the cylinder that is not mixed with the flue gases.
  • This layer of air (also called layer of air stratification) comprises only introduced air unmixed with burnt gases contained in the engine cylinder.
  • the intake air is introduced before the opening of the exhaust port, the pressure of the intake air being greater than the pressure of the flue gases, which allows to stratify the air admitted inside the cylinder.
  • the action of the intake air slightly overpressure compared to the flue gas combined with the rise of the piston after the bottom dead point, flushes the flue gases while avoiding a mixture of air admitted with the flue gases.
  • the intake air is not ejected outside the engine cylinder.
  • control method of a two-stroke internal combustion engine according to the invention may also have one or more of the following characteristics, considered individually or in any technically feasible combination.
  • the adjustment of the flue gas pressure to a value lower than said intake air pressure is achieved via the opening of a restricted flow relief valve.
  • the method according to the invention comprises a step of closing the discharge valve as soon as the flue gases have a pressure lower than the intake air pressure.
  • the method comprises a step of opening the exhaust port, the introduction of pressurized intake air into the engine cylinder continuing.
  • the adjustment of the pressure of the flue gases to a value lower than the intake air pressure is achieved by opening the exhaust port and creating a back pressure at the beginning. said opening of the exhaust port to limit the exhaust flow of the burnt gases.
  • This back pressure can be generated by reflection of acoustic waves in the exhaust pipes (not shown).
  • the exhaust sees flushes of gas that creates Acoustic waves of pressure and vacuum in the exhaust pipes.
  • the lengths of the pipes and positions of the junctions between the exhausts of each cylinder are defined so as to reflect an overpressure at the exhaust port to limit the rate of gas discharge at the beginning of its opening.
  • the method according to the invention comprises a step of closing the exhaust port when all the burnt gases are evacuated.
  • the adjusted flue gas pressure is at least 150 mbar lower than the intake air pressure, or for example of the order of 150 mbar.
  • the invention also relates to an internal combustion two-stroke engine comprising:
  • At least one intake port of pressurized air into said engine cylinder At least one intake port of pressurized air into said engine cylinder.
  • the engine further comprises a pressure regulator adapted to adjust the pressure of the burnt gases contained in said engine cylinder to a value lower than said intake air pressure.
  • the pressure regulator is formed by a restricted flow relief valve, the opening of which enables the pressure of the flue gases contained in said engine cylinder to be adjusted to a value lower than the air pressure. 'admission.
  • FIG. 1 illustrates a nonlimiting example embodiment of a two-stroke internal combustion engine according to the invention
  • FIG. 2 illustrates a block diagram of the steps of a possible implementation of a control method of a two-stroke internal combustion engine according to the invention
  • FIGS. 3A, 3B, 3C and 3D schematically illustrate various steps of the method for controlling an internal combustion two-stroke engine according to the invention detailed in support of FIG. 2.
  • FIG. 1 illustrates a nonlimiting example embodiment of a two-stroke internal combustion engine 1 according to the invention.
  • the two-stroke internal combustion engine 1 illustrated in FIG. 1 comprises:
  • a driving cylinder 2 having a longitudinal axis X
  • a pressure regulator 7 (formed by a restricted flow relief valve) adapted to adjust the pressure of the burnt gases 8 contained in the engine cylinder 2 to a value less than the intake air pressure.
  • This relief valve 7 is also located at the top dead center of the engine 1.
  • the restricted flow relief valve 7 is opened before the opening of the exhaust valve 4 in order to reduce the difference between the intake pressure and the pressure of the burnt gases of the engine cylinder 2. This decrease in pressure difference makes it possible to control the inlet air speed of the inlet air in the engine cylinder 2.
  • the two-stroke internal combustion engine 1 illustrated in FIG. 1 comprises a single exhaust valve 4 and a single discharge valve 7, but it is understood that the engine 1 according to the invention is not limited to such an embodiment. and it may comprise a plurality of discharge valves 7 and / or a plurality of exhaust valves 4.
  • the exhaust port is located near the bottom dead center of the engine and the intake port, for example controlled by a valve, is located near from the top dead center of the engine.
  • FIG. 2 illustrates a block diagram of the steps of a possible implementation of a control method 100 of a two-stroke internal combustion engine 1 according to the invention
  • FIGS. 3A, 3B, 3C and 3D illustrate schematically certain steps of the control method 100 according to the invention detailed in support of Figure 2.
  • control method 100 of a two-stroke internal combustion engine 1 comprises the following steps.
  • the control method 100 comprises a longitudinal displacement step 101 of the piston 3 in a direction X-opposite to the exhaust port 4 (FIG. 3A), the displacement being generated by the expansion of burned gases in the engine cylinder 2 and continuing until the piston 3 unclogs the intake ports 6. Simultaneously with the longitudinal displacement in the direction X- of the piston 3, the control method 100 comprises a step of pressurizing the intake air 102.
  • the control method 100 comprises an additional step 103 of adjusting the pressure of the burnt gases contained in the engine cylinder 2 to a value lower than the pressurized intake air pressure during the previous step 102.
  • the adjusted flue gas pressure is 150 mbar lower than the intake air pressure.
  • the adjustment of the flue gas pressure to a value lower than the intake air pressure is achieved via the opening of the restricted flow relief valve 7 ( Figure 3B). The opening of the relief valve 7 precedes the unclogging of the intake ports 6 by the piston 3.
  • the closure 104 of the relief valve 7 is triggered.
  • the piloting method 100 comprises a step of introducing pressurized admission air 105 into the engine cylinder 2, the intake air forming a layer laminating layer 9 covering the top 10 of the piston 3.
  • the lamination layer 9 formed of pressurized intake air forms a layer separating the top 10 of the piston 3 of the burnt gases 8.
  • this layer 9 lamination repels the burnt gases 8 towards the exhaust port 4.
  • the piston 3 discovers the intake ports 6 allowing the arrival of the intake air to form the lamination layer 9.
  • the burned gases 8 are then pushed up the engine cylinder 2.
  • the exhaust port 4 remains closed during this phase, the cylinder pressure is restored to the value of the intake air pressure.
  • the control method 100 comprises an opening step the exhaust port 106 ( Figure 3D), the introduction of pressurized intake air continuing.
  • the exhaust port 4 to open the exhaust port 4, the exhaust valve is opened.
  • the lifting of the valve exhaust 4 is adapted to allow to control the maximum exhaust flow by maintaining the cylinder pressure close to the intake pressure.
  • control method 100 includes a step of moving the piston 107 in the X + direction of the exhaust port 4 causing the escape of the burnt gases 8 via the exhaust valve 4 while the engine cylinder 2 fills with air from the exhaust port 4. admission to the rear of the laminated layer 9, in other words between the top 10 of the piston 2 and the laminated layer 9.
  • the mixture between the intake air and the flue gas is almost non-existent because of the low speed of movement of the these, the low pressure difference of the latter and the low speed of movement of the piston 3.
  • the intake ports are formed by intake ports.
  • the intake flow during the exhaust phase of the burnt gases can be adapted by the shape of the intake ports to prevent the gas column, which moves upwards in the engine cylinder 2, from entering in oscillation.
  • the inlet ports are oriented to feed the cylinder tangentially, giving the flow a vortex movement (well known as English swirl). The expected advantages are a better stability of the stratified layer of fresh air during the movement of the piston and greater robustness to turbulence, which may appear in particular at the exhaust valve.
  • the control method 100 includes a closing step 108 of the exhaust valve 4.
  • the displacement of the piston 3 in the X + direction of the exhaust port 4 is continued until the intake ports 6 are closed by the piston 3 ( Figure 3D).
  • the skirt 11 of the piston obstructs the intake ports 6 when the piston 3 is at top dead center. This feature prevents the escape of fresh air to the crankcase.
  • the piston 3 may comprise a sealing segment at the bottom of the skirt 11 in order to limit the loss of air under pressure towards the housing.
  • the opening and closing of the intake port 6 can be controlled, for example, by a bushel or spinning liner.
  • the role of the exhaust valve 4 is to evacuate most of the flue gas 8, while controlling the exhaust rate of the flue gas 8 throughout the piston sweeping. This makes it possible to limit the amount of air introduced into the exhaust and to limit the turbulence and therefore the mixing between the intake air and the flue gases.
  • This exhaust valve is defined to limit the distortion of the burnt gas velocity field in the exhaust zone, and thus avoid disturbing the stratified air layer created on the piston head.
  • the almost non-existence of a mixture between the intake air and the flue gases makes it possible to limit the residual portion of flue gases during each engine cycle. Therefore, the proportion of available oxygen is greater to increase the pressure and the engine cycle temperature, and therefore its performance.
  • the invention makes it possible to reduce the dilution of the exhaust gases by the air admitted during the engine cycle.
  • the temperature of the exhaust gas is therefore higher than in a conventional engine, which makes it possible to increase the proportion of energy recoverable in the exhaust on a turbine for example.
  • the solution requires the use of an air pressurization, typically performed by a compressor driven by the crankshaft or a turbocharger.
  • the supercharging increases the air and fuel masses at each cycle, so the power / displacement ratio.

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

Abstract

The invention relates to a method for controlling (100) a two-stroke internal combustion engine (1), said control method (100) comprising the following steps: longitudinal movement of a piston (3) in the direction of the bottom dead centre of an engine (101), said movement (101) being triggered by the expansion of burned gases (8) in the master cylinder (2), during said longitudinal displacement (101) of said piston (3), there is a step of admission air pressurisation (102), adjustment of the pressure of said burned gases to a value lower than said admission air pressure (103), and introduction of pressurised admission air (105) into said cylinder, the air introduced forming a stratification layer (9) redirecting said burned gases (8) towards said exhaust port (4).

Description

PROCEDE DE PILOTAGE D'UN MOTEUR DEUX-TEMPS A COMBUSTION  METHOD FOR CONTROLLING A COMBUSTION TWO-STROKE ENGINE
INTERNE  INTERNAL
DOMAINE TECHNIQUE TECHNICAL AREA
La présente invention concerne un procédé de pilotage d'un moteur deux- temps à combustion interne ainsi qu'un moteur deux-temps à combustion interne destiné à être piloté conformément au procédé de pilotage selon l'invention. Un tel moteur et un tel procédé de pilotage peuvent être avantageusement mis en œuvre dans le domaine aéronautique.  The present invention relates to a control method of a two-stroke internal combustion engine and a two-stroke internal combustion engine to be controlled according to the control method according to the invention. Such a motor and such a control method can be advantageously implemented in the aeronautical field.
ETAT DE LA TECHNIQUE ANTERIEUR STATE OF THE PRIOR ART
On connaît les moteurs deux-temps à combustion interne de type équicourant, de tels moteurs comportant :  Equivalent two-stroke internal combustion engines are known, such engines comprising:
• un cylindre moteur présentant un axe longitudinal X,  • a motor cylinder having a longitudinal axis X,
• un piston disposé dans le cylindre moteur, le piston étant apte à effectuer un déplacement selon l'axe longitudinal X,  A piston disposed in the engine cylinder, the piston being capable of moving along the longitudinal axis X,
• un port d'échappement localisé à une extrémité du cylindre moteur permettant l'échappement des gaz brûlés, et  An exhaust port located at one end of the engine cylinder for exhausting the flue gases, and
• un port d'admission d'air dans le cylindre moteur.  • an air intake port in the engine cylinder.
Un tel moteur deux-temps à combustion interne se caractérise par un temps moteur pour chaque tour de vilebrequin. Le piston que comporte le moteur participe uniquement à la compression et la détente des gaz contenus dans le cylindre du moteur, l'évacuation des gaz brûlés et le remplissage du cylindre moteur en air se réalisant par d'autres mécanismes. Plus particulièrement, une source d'air comprimé, au point mort bas du moteur, assure le remplissage en air du cylindre moteur en repoussant simultanément les gaz brûlés en direction du port d'échappement. L'ouverture du port d'échappement permet l'évacuation des gaz brûlés.  Such an internal combustion two-stroke engine is characterized by a driving time for each crankshaft revolution. The piston contained in the engine only contributes to the compression and expansion of the gases contained in the engine cylinder, the evacuation of the burnt gases and the filling of the engine cylinder in air being achieved by other mechanisms. More particularly, a source of compressed air at the bottom dead center of the engine ensures the air filling of the engine cylinder by simultaneously pushing the flue gases towards the exhaust port. The opening of the exhaust port allows the evacuation of burnt gases.
Afin de favoriser le remplissage du cylindre moteur, il est nécessaire de réaliser une dépression dans le cylindre moteur. Cependant, une telle dépression augmente la vitesse d'entrée de l'air comprimé dans le cylindre et génère un phénomène de mixtion de l'air comprimé et des gaz brûlés. Le mélange de l'air comprimé et des gaz brûlés est d'autant plus élevé que la turbulence est importante dans le cylindre. Le mélange de l'air introduit et des gaz brûlés entraîne, d'une part, une perte d'une partie de l'air introduit vers l'échappement sans que celle-ci participe à la combustion, et d'autre part, une pollution de l'air introduit par des gaz brûlés et chauds dans le cylindre réduisant de facto le rendement de la combustion. To promote the filling of the engine cylinder, it is necessary to achieve a vacuum in the engine cylinder. However, such a depression increases the rate of entry of compressed air into the cylinder and generates a phenomenon of mixing compressed air and flue gases. The mixing of the compressed air and the flue gas is all the higher as the turbulence is important in the cylinder. The mixture of the introduced air and the burnt gases causes, on the one hand, a loss of a part of the air introduced towards the exhaust without this one participating in the combustion, and on the other hand, a air pollution introduced by hot and flammable gases into the cylinder reducing the efficiency of combustion de facto.
De façon conventionnelle, la mise au point du moteur consiste à assurer l'échappement de la totalité des gaz brûlés, ce qui implique en contrepartie qu'une partie d'air introduit, due au phénomène de mélange, soit perdue directement à l'échappement.  Conventionally, the development of the engine is to ensure the escape of all the flue gas, which implies in return that a portion of air introduced, due to the phenomenon of mixing, is lost directly to the exhaust .
EXPOSE DE L'INVENTION SUMMARY OF THE INVENTION
L'invention a donc pour objectif de remédier aux inconvénients de l'état de la technique. Dans ce contexte, la présente invention a pour but de fournir un procédé de pilotage d'un moteur deux-temps à combustion interne présentant un rendement de combustion optimisé.  The invention therefore aims to overcome the disadvantages of the state of the art. In this context, the present invention aims to provide a method for controlling an internal combustion two-stroke engine having an optimized combustion efficiency.
A cette fin, l'invention porte sur un procédé de pilotage d'un moteur deux- temps à combustion interne, ledit moteur comportant :  To this end, the invention relates to a method for controlling an internal combustion two-stroke engine, said engine comprising:
• un cylindre moteur présentant un axe longitudinal X,  • a motor cylinder having a longitudinal axis X,
• un piston disposé dans ledit cylindre moteur, ledit piston étant apte à effectuer un déplacement selon ledit axe longitudinal X,  A piston disposed in said engine cylinder, said piston being able to move along said longitudinal axis X,
• un port d'échappement comportant au moins une soupape d'échappement,  An exhaust port having at least one exhaust valve,
• un port d'admission d'air dans ledit cylindre moteur,  An air intake port in said engine cylinder,
ledit procédé de pilotage comportant les étapes suivantes : said driving method comprising the following steps:
• déplacement longitudinal dudit piston en direction du point mort bas dudit moteur, ledit déplacement étant engendré par la détente de gaz brûlés dans ledit cylindre moteur, au cours dudit déplacement longitudinal dudit piston le procédé comporte une étape de pressurisation d'air d'admission,  • longitudinal displacement of said piston towards the bottom dead center of said engine, said displacement being generated by the expansion of burnt gases in said engine cylinder, during said longitudinal displacement of said piston the process comprises a step of pressurizing intake air,
• ajustement de la pression desdits gaz brûlés à une valeur inférieure à ladite pression d'air d'admission,  Adjusting the pressure of said flue gases to a value lower than said intake air pressure,
• introduction dans ledit cylindre d'air admission pressurisé, l'air admis formant une couche de stratification repoussant lesdits gaz brûlés en direction dudit port d'échappement. On entend pour la suite de la description par couche de stratification une couche d'air admis dans le cylindre non mélangée aux gaz brûlés. Cette couche d'air (nommée également couche d'air de stratification) comporte uniquement de l'air introduit non mélangé avec des gaz brûlés que contient le cylindre moteur. Introduction into said pressurized admission air cylinder, the intake air forming a lamination layer pushing said flue gases towards said exhaust port. For the rest of the description, a stratification layer is understood to mean a layer of air admitted into the cylinder that is not mixed with the flue gases. This layer of air (also called layer of air stratification) comprises only introduced air unmixed with burnt gases contained in the engine cylinder.
Grâce à l'invention, l'air d'admission est introduit avant l'ouverture du port d'échappement, la pression de l'air d'admission étant supérieure à la pression des gaz brûlés, ce qui permet de stratifier l'air admis à l'intérieur du cylindre. Une fois le port d'échappement ouvert, l'action de l'air d'admission en légère surpression par rapport au gaz brûlés combinée à la remontée du piston après le point mort bas, chasse les gaz brûlés tout en évitant un mélange de l'air admis avec les gaz brûlés. En outre, comme aucun mélange n'est réalisé, l'air admis n'est pas éjecté en dehors du cylindre moteur.  Thanks to the invention, the intake air is introduced before the opening of the exhaust port, the pressure of the intake air being greater than the pressure of the flue gases, which allows to stratify the air admitted inside the cylinder. Once the exhaust port is open, the action of the intake air slightly overpressure compared to the flue gas combined with the rise of the piston after the bottom dead point, flushes the flue gases while avoiding a mixture of air admitted with the flue gases. In addition, since no mixing is performed, the intake air is not ejected outside the engine cylinder.
Le procédé de pilotage d'un moteur deux-temps à combustion interne selon l'invention peut également présenter une ou plusieurs des caractéristiques ci-après, considérées individuellement ou selon toutes les combinaisons techniquement réalisables.  The control method of a two-stroke internal combustion engine according to the invention may also have one or more of the following characteristics, considered individually or in any technically feasible combination.
Dans une réalisation non limitative, l'ajustement de la pression des gaz brûlés à une valeur inférieure à ladite pression d'air d'admission est réalisé via l'ouverture d'une soupape de décharge à débit restreint.  In a non-limiting embodiment, the adjustment of the flue gas pressure to a value lower than said intake air pressure is achieved via the opening of a restricted flow relief valve.
Dans une réalisation non limitative, le procédé selon l'invention comporte une étape de fermeture de la soupape de décharge dès lors que les gaz brûlés ont une pression inférieure à la pression d'air d'admission.  In a non-limiting embodiment, the method according to the invention comprises a step of closing the discharge valve as soon as the flue gases have a pressure lower than the intake air pressure.
Dans une réalisation non limitative, dès lors que la pression contenue dans le cylindre formée par la couche de stratification et les gaz brûlés est sensiblement égale à la valeur de la pression d'air d'admission, le procédé comporte une étape d'ouverture du port d'échappement, l'introduction d'air d'admission pressurisé dans le cylindre moteur se poursuivant.  In a non-limiting embodiment, since the pressure contained in the cylinder formed by the lamination layer and the flue gases is substantially equal to the value of the intake air pressure, the method comprises a step of opening the exhaust port, the introduction of pressurized intake air into the engine cylinder continuing.
Dans une réalisation non limitative, l'ajustement de la pression des gaz brûlés à une valeur inférieure à la pression d'air d'admission est réalisé par l'ouverture du port d'échappement et la création d'une contre-pression en début de ladite ouverture du port d'échappement afin de limiter le débit d'échappement des gaz brûlés. Cette contre-pression peut être générée par réflexion d'ondes acoustiques dans les tubulures d'échappement (non représentées). Dans les moteurs alternatifs, l'échappement voit passer des bouffées de gaz qui crée des ondes acoustiques de surpression et de dépression dans les tubulures d'échappement. Dans cette configuration particulière de la solution, les longueurs des tubulures et positions des jonctions entre échappements de chaque cylindre sont définis de façon à réfléchir une surpression au port d'échappement pour limiter la vitesse de vidange des gaz au début de son ouverture. In a non-limiting embodiment, the adjustment of the pressure of the flue gases to a value lower than the intake air pressure is achieved by opening the exhaust port and creating a back pressure at the beginning. said opening of the exhaust port to limit the exhaust flow of the burnt gases. This back pressure can be generated by reflection of acoustic waves in the exhaust pipes (not shown). In alternative engines, the exhaust sees flushes of gas that creates Acoustic waves of pressure and vacuum in the exhaust pipes. In this particular configuration of the solution, the lengths of the pipes and positions of the junctions between the exhausts of each cylinder are defined so as to reflect an overpressure at the exhaust port to limit the rate of gas discharge at the beginning of its opening.
Dans une réalisation non limitative, le procédé selon l'invention comporte une étape de fermeture du port d'échappement lorsque la totalité des gaz brûlés est évacuée.  In a non-limiting embodiment, the method according to the invention comprises a step of closing the exhaust port when all the burnt gases are evacuated.
Dans une réalisation non limitative, la pression des gaz brûlés ajustée est d'au moins 150 mbar inférieure à la pression d'air d'admission, ou par exemple de l'ordre de 150 mbar.  In a non-limiting embodiment, the adjusted flue gas pressure is at least 150 mbar lower than the intake air pressure, or for example of the order of 150 mbar.
L'invention porte également sur un moteur deux-temps à combustion interne comportant :  The invention also relates to an internal combustion two-stroke engine comprising:
• un cylindre moteur présentant un axe longitudinal X,  • a motor cylinder having a longitudinal axis X,
• un piston disposé dans ledit cylindre moteur, ledit piston étant apte à effectuer un déplacement selon ledit axe longitudinal X,  A piston disposed in said engine cylinder, said piston being able to move along said longitudinal axis X,
• un port d'échappement comportant au moins une soupape d'échappement,  An exhaust port having at least one exhaust valve,
• des moyens de pressurisation d'air d'admission,  • intake air pressurization means,
• au moins un port d'admission d'air pressurisé dans ledit cylindre moteur.  At least one intake port of pressurized air into said engine cylinder.
Le moteur comporte en outre un régulateur de pression adapté pour ajuster la pression des gaz brûlés contenus dans ledit cylindre moteur à une valeur inférieure à ladite pression d'air d'admission.  The engine further comprises a pressure regulator adapted to adjust the pressure of the burnt gases contained in said engine cylinder to a value lower than said intake air pressure.
Dans une réalisation non limitative, le régulateur de pression est formé par une soupape de décharge à débit restreint dont l'ouverture permet l'ajustement de la pression des gaz brûlés contenus dans ledit cylindre moteur à une valeur inférieure à la pression d'air d'admission.  In a non-limiting embodiment, the pressure regulator is formed by a restricted flow relief valve, the opening of which enables the pressure of the flue gases contained in said engine cylinder to be adjusted to a value lower than the air pressure. 'admission.
BREVE DESCRIPTION DES FIGURES BRIEF DESCRIPTION OF THE FIGURES
D'autres caractéristiques et avantages de l'invention rassortiront clairement de la description qui en est donnée ci-dessous, à titre indicatif et nullement limitatif, en référence aux figures annexées, parmi lesquelles : - la figure 1 illustre un exemple non limitatif de réalisation d'un moteur deux-temps à combustion interne conforme à l'invention, Other features and advantages of the invention will clearly be described in the description given below, by way of indication and in no way limitative, with reference to the appended figures, among which: FIG. 1 illustrates a nonlimiting example embodiment of a two-stroke internal combustion engine according to the invention,
- la figure 2 illustre un synoptique des étapes d'une mise en œuvre possible d'un procédé de pilotage d'un moteur deux-temps à combustion interne selon l'invention, et  FIG. 2 illustrates a block diagram of the steps of a possible implementation of a control method of a two-stroke internal combustion engine according to the invention, and
- les figures 3A, 3B, 3C et 3D illustrent de façon schématique différentes étapes du procédé de pilotage d'un moteur deux-temps à combustion interne selon l'invention détaillé à l'appui de la figure 2.  FIGS. 3A, 3B, 3C and 3D schematically illustrate various steps of the method for controlling an internal combustion two-stroke engine according to the invention detailed in support of FIG. 2.
Pour des raisons de clarté, seuls les éléments utiles pour la compréhension de l'invention ont été représentés et ceci, sans respect de l'échelle et de manière schématique. En outre, les éléments similaires situés sur différentes figures comportent des références identiques.  For the sake of clarity, only the elements useful for understanding the invention have been shown and this, without respect for the scale and schematically. In addition, the similar elements in different figures have identical references.
DESCRIPTION DETAILLEE D'AU MOINS UN MODE DE REALISATION DE L'INVENTION DETAILED DESCRIPTION OF AT LEAST ONE EMBODIMENT OF THE INVENTION
La figure 1 illustre un exemple non limitatif de réalisation d'un moteur deux-temps à combustion interne 1 conforme à l'invention. Le moteur deux- temps à combustion interne 1 illustré sur la figure 1 comporte :  FIG. 1 illustrates a nonlimiting example embodiment of a two-stroke internal combustion engine 1 according to the invention. The two-stroke internal combustion engine 1 illustrated in FIG. 1 comprises:
- un cylindre moteur 2 présentant un axe longitudinal X,  a driving cylinder 2 having a longitudinal axis X,
- un piston 3 disposé dans le cylindre moteur 2, le piston 3 étant apte à effectuer un mouvement de va-et-vient dans le cylindre moteur 2 selon l'axe longitudinal X,  a piston 3 disposed in the engine cylinder 2, the piston 3 being capable of reciprocating in the engine cylinder 2 along the longitudinal axis X,
- un port d'échappement 4 formé par une soupape d'échappement, le port d'échappement 4 étant localisé au point mort haut du moteur 1 ,  an exhaust port 4 formed by an exhaust valve, the exhaust port 4 being located at the top dead center of the engine 1,
- des moyens de pressurisation d'air d'admission 5,  intake air pressurization means 5,
- deux ports d'admission d'air pressurisé 6 dans le cylindre moteur 2, les deux ports d'admission 6 étant situés au niveau du point mort bas du moteur 1, et  two pressurized air intake ports 6 in the engine cylinder 2, the two intake ports 6 being located at the bottom dead center of the engine 1, and
- un régulateur de pression 7 (formé par une soupape de décharge à débit restreint) adapté pour ajuster la pression des gaz brûlés 8 contenus dans le cylindre moteur 2 à une valeur inférieure à la pression d'air d'admission. Cette soupape de décharge 7 est également située au point mort haut du moteur 1. Ainsi, le moteur deux-temps à combustion interne 1 selon l'invention est muni de deux types de soupapes dont l'ouverture est séquencée afin d'optimiser le débit d'évacuation des gaz brûlés contenus dans le cylindre moteur 2. - A pressure regulator 7 (formed by a restricted flow relief valve) adapted to adjust the pressure of the burnt gases 8 contained in the engine cylinder 2 to a value less than the intake air pressure. This relief valve 7 is also located at the top dead center of the engine 1. Thus, the two-stroke internal combustion engine 1 according to the invention is provided with two types of valves whose opening is sequenced in order to optimize the discharge rate of the burnt gases contained in the engine cylinder 2.
Dans une mise en œuvre particulièrement intéressante mais non limitative, la soupape de décharge 7 à débit restreint est ouverte avant l'ouverture de la soupape d'échappement 4 afin de diminuer la différence entre la pression d'admission et la pression des gaz brûlés du cylindre moteur 2. Cette diminution de différence de pression permet de contrôler la vitesse d'entée de l'air d'admission dans le cylindre moteur 2.  In a particularly advantageous but non-limiting implementation, the restricted flow relief valve 7 is opened before the opening of the exhaust valve 4 in order to reduce the difference between the intake pressure and the pressure of the burnt gases of the engine cylinder 2. This decrease in pressure difference makes it possible to control the inlet air speed of the inlet air in the engine cylinder 2.
Le moteur deux-temps à combustion interne 1 illustré sur la figure 1 comporte une unique soupape d'échappement 4 et une unique soupape de décharge 7 mais il est entendu que le moteur 1 selon l'invention n'est pas limité à une telle réalisation et il peut comporter plusieurs soupapes de décharge 7 et/ou plusieurs soupapes d'échappement 4.  The two-stroke internal combustion engine 1 illustrated in FIG. 1 comprises a single exhaust valve 4 and a single discharge valve 7, but it is understood that the engine 1 according to the invention is not limited to such an embodiment. and it may comprise a plurality of discharge valves 7 and / or a plurality of exhaust valves 4.
Dans une autre réalisation non illustrée du moteur deux-temps à combustion interne selon l'invention, le port d'échappement est situé près du point mort bas du moteur et le port d'admission, par exemple commandé par une soupape, est situé près du point mort haut du moteur. Cette réalisation permet de profiter de l'inertie des gaz brûlés lors de la détente pour l'échappement de ces derniers.  In another non-illustrated embodiment of the two-stroke internal combustion engine according to the invention, the exhaust port is located near the bottom dead center of the engine and the intake port, for example controlled by a valve, is located near from the top dead center of the engine. This embodiment makes it possible to take advantage of the inertia of the gases burned during the relaxation for the exhaust of the latter.
La figure 2 illustre un synoptique des étapes d'une mise en œuvre possible d'un procédé de pilotage 100 d'un moteur deux-temps à combustion interne 1 selon l'invention, et les figures 3A, 3B, 3C et 3D illustrent de façon schématique certaines étapes du procédé de pilotage 100 selon l'invention détaillée à l'appui de la figure 2.  FIG. 2 illustrates a block diagram of the steps of a possible implementation of a control method 100 of a two-stroke internal combustion engine 1 according to the invention, and FIGS. 3A, 3B, 3C and 3D illustrate schematically certain steps of the control method 100 according to the invention detailed in support of Figure 2.
Dans une mise en œuvre non limitative, le procédé de pilotage 100 d'un moteur deux-temps à combustion interne 1 comporte les étapes suivantes.  In a nonlimiting implementation, the control method 100 of a two-stroke internal combustion engine 1 comprises the following steps.
Le procédé de pilotage 100 comporte une étape de déplacement longitudinal 101 du piston 3 dans une direction X- opposée au port d'échappement 4 (figure 3A), le déplacement étant engendré par la détente de gaz brûlés dans le cylindre moteur 2 et se poursuivant jusqu'à ce que le piston 3 désobstrue les ports d'admission 6. Simultanément au déplacement longitudinal selon la direction X- du piston 3, le procédé de pilotage 100 comporte une étape de pressurisation d'air d'admission 102. The control method 100 comprises a longitudinal displacement step 101 of the piston 3 in a direction X-opposite to the exhaust port 4 (FIG. 3A), the displacement being generated by the expansion of burned gases in the engine cylinder 2 and continuing until the piston 3 unclogs the intake ports 6. Simultaneously with the longitudinal displacement in the direction X- of the piston 3, the control method 100 comprises a step of pressurizing the intake air 102.
Le procédé de pilotage 100 comporte une étape supplémentaire d'ajustement 103 de la pression des gaz brûlés contenus dans le cylindre moteur 2 à une valeur inférieure à la pression d'air d'admission pressurisé lors de l'étape précédente 102. Par exemple, la pression des gaz brûlés ajustée est de 150 mbar inférieure à la pression d'air d'admission. Dans une mise en œuvre non limitative, l'ajustement de la pression des gaz brûlés à une valeur inférieure à la pression d'air d'admission est réalisé via l'ouverture de la soupape de décharge à débit restreint 7 (figure 3B). L'ouverture de la soupape de décharge 7 précède la désobstruction des ports d'admission 6 par le piston 3.  The control method 100 comprises an additional step 103 of adjusting the pressure of the burnt gases contained in the engine cylinder 2 to a value lower than the pressurized intake air pressure during the previous step 102. For example, the adjusted flue gas pressure is 150 mbar lower than the intake air pressure. In a nonlimiting implementation, the adjustment of the flue gas pressure to a value lower than the intake air pressure is achieved via the opening of the restricted flow relief valve 7 (Figure 3B). The opening of the relief valve 7 precedes the unclogging of the intake ports 6 by the piston 3.
Dans une mise en œuvre non limitative, dès lors que les gaz brûlés ont une pression inférieure à la pression d'air d'admission, la fermeture 104 de la soupape de décharge 7 est déclenchée.  In a nonlimiting implementation, since the flue gases have a lower pressure than the intake air pressure, the closure 104 of the relief valve 7 is triggered.
Dès lors que les ports d'admission 6 sont désobstrués (Figure 3C) par le piston 3, le procédé de pilotage 100 comporte une étape d'introduction d'air admission pressurisé 105 dans le cylindre moteur 2, l'air admis formant une couche de stratification 9 recouvrant le sommet 10 du piston 3. La couche de stratification 9 formée d'air d'admission pressurisé forme une couche séparant le sommet 10 du piston 3 des gaz brûlés 8. Ainsi, cette couche de stratification 9 repousse les gaz brûlés 8 en direction du port d'échappement 4.  As soon as the intake ports 6 are unobstructed (FIG. 3C) by the piston 3, the piloting method 100 comprises a step of introducing pressurized admission air 105 into the engine cylinder 2, the intake air forming a layer laminating layer 9 covering the top 10 of the piston 3. The lamination layer 9 formed of pressurized intake air forms a layer separating the top 10 of the piston 3 of the burnt gases 8. Thus, this layer 9 lamination repels the burnt gases 8 towards the exhaust port 4.
En d'autres termes, le piston 3 découvre les ports d'admission 6 autorisant l'arrivée de l'air d'admission pour constituer la couche de stratification 9. Les gaz brûlés 8 sont alors repoussés vers le haut du cylindre moteur 2. Comme le port d'échappement 4 reste fermé pendant cette phase, la pression cylindre se rétablie à la valeur de la pression d'air d'admission.  In other words, the piston 3 discovers the intake ports 6 allowing the arrival of the intake air to form the lamination layer 9. The burned gases 8 are then pushed up the engine cylinder 2. As the exhaust port 4 remains closed during this phase, the cylinder pressure is restored to the value of the intake air pressure.
Dès lors que la pression contenue dans le cylindre moteur 2 formée par la couche de stratification 9 et les gaz brûlés 8 est sensiblement égale à la valeur de la pression d'air d'admission, le procédé de pilotage 100 comporte une étape d'ouverture du port d'échappement 106 (figure 3D), l'introduction d'air d'admission pressurisé se poursuivant. Dans notre exemple, pour ouvrir le port d'échappement 4, on ouvre la soupape d'échappement. La levée de la soupape d'échappement 4 est adaptée pour permettre de piloter le débit d'échappement maximal en maintenant la pression cylindre proche de la pression d'admission. As soon as the pressure contained in the engine cylinder 2 formed by the lamination layer 9 and the flue gases 8 is substantially equal to the value of the intake air pressure, the control method 100 comprises an opening step the exhaust port 106 (Figure 3D), the introduction of pressurized intake air continuing. In our example, to open the exhaust port 4, the exhaust valve is opened. The lifting of the valve exhaust 4 is adapted to allow to control the maximum exhaust flow by maintaining the cylinder pressure close to the intake pressure.
Puis le procédé de pilotage 100 comporte une étape de déplacement du piston 107 en direction X+ du port d'échappement 4 entraînant l'échappement des gaz brûlés 8 via la soupape d'échappement 4 tandis que le cylindre moteur 2 se remplit d'air d'admission à l'arrière de la couche stratifiée 9, autrement dit entre le sommet 10 du piston 2 et la couche stratifiée 9. Le mélange entre l'air admis et les gaz brûlés est quasi inexistant en raison de la faible vitesse de déplacement de ces derniers, de la faible différence de pression de ces derniers et de la faible vitesse de déplacement du piston 3.  Then the control method 100 includes a step of moving the piston 107 in the X + direction of the exhaust port 4 causing the escape of the burnt gases 8 via the exhaust valve 4 while the engine cylinder 2 fills with air from the exhaust port 4. admission to the rear of the laminated layer 9, in other words between the top 10 of the piston 2 and the laminated layer 9. The mixture between the intake air and the flue gas is almost non-existent because of the low speed of movement of the these, the low pressure difference of the latter and the low speed of movement of the piston 3.
Dans un mode de réalisation non limitatif, les ports d'admission sont formés par des lumières d'admission. Ainsi, le débit d'admission pendant la phase d'échappement des gaz brûlés peut être adapté par la forme des lumières d'admission pour éviter que la colonne de gaz, qui se met en mouvement ascendant dans le cylindre moteur 2, n'entre en oscillation. Dans une autre réalisation de l'invention, les lumières d'admission sont orientés de façon à alimenter le cylindre de façon tangentielle, donnant à l'écoulement un mouvement de tourbillon (bien connu sous la dénomination anglais swirl). Les avantages attendus sont une meilleure stabilité de la couche stratifiée d'air frais pendant le déplacement du piston et une plus grande robustesse aux turbulences, susceptibles d'apparaître notamment au niveau de la soupape d'échappement.  In a non-limiting embodiment, the intake ports are formed by intake ports. Thus, the intake flow during the exhaust phase of the burnt gases can be adapted by the shape of the intake ports to prevent the gas column, which moves upwards in the engine cylinder 2, from entering in oscillation. In another embodiment of the invention, the inlet ports are oriented to feed the cylinder tangentially, giving the flow a vortex movement (well known as English swirl). The expected advantages are a better stability of the stratified layer of fresh air during the movement of the piston and greater robustness to turbulence, which may appear in particular at the exhaust valve.
Lorsque la totalité des gaz brûlés 8 est évacuée, le procédé de pilotage 100 comporte une étape de fermeture 108 de la soupape d'échappement 4. Le déplacement du piston 3 en direction X+ du port d'échappement 4 est poursuivi jusqu'à ce que les ports d'admission 6 soient obturés par le piston 3 (Figure 3D). Dans cette réalisation, la jupe 11 du piston obstrue les ports d'admission 6 lorsque le piston 3 est au point mort haut. Cette particularité permet d'empêcher la fuite d'air frais vers le carter moteur. Dans cette réalisation, le piston 3 peut comporter un segment d'étanchéité en bas de la jupe 11 afin de limiter la perte d'air sous pression vers le carter. Dans une autre réalisation non illustrée, pour limiter la perte d'air sous pression vers le carter, l'ouverture et la fermeture du port d'admission 6 peuvent être commandées, par exemple, par une distribution à boisseau ou à chemise louvoyante. When all the burned gases 8 is evacuated, the control method 100 includes a closing step 108 of the exhaust valve 4. The displacement of the piston 3 in the X + direction of the exhaust port 4 is continued until the intake ports 6 are closed by the piston 3 (Figure 3D). In this embodiment, the skirt 11 of the piston obstructs the intake ports 6 when the piston 3 is at top dead center. This feature prevents the escape of fresh air to the crankcase. In this embodiment, the piston 3 may comprise a sealing segment at the bottom of the skirt 11 in order to limit the loss of air under pressure towards the housing. In another embodiment not illustrated, to limit the loss of air under pressure to the housing, the opening and closing of the intake port 6 can be controlled, for example, by a bushel or spinning liner.
Par ailleurs, il convient de noter que le rôle de la soupape d'échappement 4 est d'évacuer la plus grande partie des gaz brûlés 8, tout en contrôlant la vitesse d'échappement des gaz brûlés 8 tout au long du balayage du piston. Ceci permet de limiter la part d'air introduit à l'échappement et de limiter la turbulence donc le mélange entre l'air admis et les gaz brûlés. Cette soupape d'échappement est définie pour limiter la distorsion du champ de vitesse des gaz brûlés dans la zone d'échappement, et donc éviter de perturber la couche d'air stratifiée créée sur la tête du piston.  Furthermore, it should be noted that the role of the exhaust valve 4 is to evacuate most of the flue gas 8, while controlling the exhaust rate of the flue gas 8 throughout the piston sweeping. This makes it possible to limit the amount of air introduced into the exhaust and to limit the turbulence and therefore the mixing between the intake air and the flue gases. This exhaust valve is defined to limit the distortion of the burnt gas velocity field in the exhaust zone, and thus avoid disturbing the stratified air layer created on the piston head.
Le procédé ainsi que le moteur selon l'invention permettent avantageusement :  The method and the motor according to the invention advantageously allow:
- une amélioration du rendement moteur, en effet : an improvement in engine efficiency, in fact:
o La quasi-inexistence de mélange entre l'air admis et les gaz brûlés permet de limiter la part résiduelle de gaz brûlés à chaque cycle moteur. Par conséquent, la proportion d'oxygène disponible est plus importante permettant d'augmenter la pression et la température de cycle moteur, et par conséquent son rendement. o L'invention permet de diminuer la dilution des gaz d'échappement par l'air admis lors du cycle moteur. La température des gaz d'échappement est donc plus élevée que dans un moteur conventionnel, ce qui permet d'augmenter la part d'énergie récupérable à l'échappement sur une turbine par exemple.  o The almost non-existence of a mixture between the intake air and the flue gases makes it possible to limit the residual portion of flue gases during each engine cycle. Therefore, the proportion of available oxygen is greater to increase the pressure and the engine cycle temperature, and therefore its performance. The invention makes it possible to reduce the dilution of the exhaust gases by the air admitted during the engine cycle. The temperature of the exhaust gas is therefore higher than in a conventional engine, which makes it possible to increase the proportion of energy recoverable in the exhaust on a turbine for example.
- une augmentation de la puissance spécifique :  - an increase in the specific power:
o Une moindre part d'air d'admis (donc comburant) est perdue directement à l'échappement, ce qui permet de réduire le besoin en air du moteur, et donc la cylindrée.  o A smaller part of the intake air (thus combustive) is lost directly to the exhaust, which reduces the need for engine air, and therefore the engine capacity.
o La solution nécessite l'utilisation d'une pressurisation d'air, typiquement réalisée par un compresseur entraîné par le vilebrequin ou un turbocompresseur. La suralimentation permet d'augmenter les masses d'air et de carburant à chaque cycle, donc le ratio puissance/cylindrée.  o The solution requires the use of an air pressurization, typically performed by a compressor driven by the crankshaft or a turbocharger. The supercharging increases the air and fuel masses at each cycle, so the power / displacement ratio.

Claims

REVENDICATIONS 1 . Procédé de pilotage (100) d'un moteur deux-temps à combustion interne (1 ), ledit moteur (1 ) comportant :  CLAIMS 1. A method of controlling (100) an internal combustion two-stroke engine (1), said engine (1) comprising:
- un cylindre moteur (2) présentant un axe longitudinal (X),  a driving cylinder (2) having a longitudinal axis (X),
- un piston (3) disposé dans ledit cylindre moteur (2), ledit piston (3) étant apte à effectuer un déplacement selon ledit axe longitudinal (X),  a piston (3) disposed in said driving cylinder (2), said piston (3) being able to move along said longitudinal axis (X),
- un port d'échappement (4) de gaz brûlés (8),  an exhaust port (4) for burnt gases (8),
- un port d'admission d'air (6) dans ledit cylindre moteur (2), ledit procédé de pilotage (100) comportant les étapes suivantes :  an air intake port (6) in said engine cylinder (2), said control method (100) comprising the following steps:
déplacement longitudinal dudit piston en direction du point mort bas dudit moteur (101 ), ledit déplacement (101 ) étant engendré par la détente de gaz brûlés (8) dans ledit cylindre moteur (2), au cours dudit déplacement longitudinal (101 ) dudit piston (3) le procédé (100) comporte une étape de pressurisation d'air d'admission (102),  longitudinal displacement of said piston towards the bottom dead center of said engine (101), said displacement (101) being generated by the expansion of burnt gases (8) in said engine cylinder (2), during said longitudinal displacement (101) of said piston (3) the method (100) includes an intake air pressurization step (102),
ajustement de la pression desdits gaz brûlés à une valeur inférieure à ladite pression d'air d'admission (103),  adjusting the pressure of said flue gases to a value lower than said intake air pressure (103),
introduction dans ledit cylindre d'air admission pressurisé (105), le port d'échappement (4) restant fermé pendant cette phase d'introduction d'air d'admission (105), l'air admis formant une couche de stratification (9) repoussant lesdits gaz brûlés (8) en direction dudit port d'échappement (4).  introduction into said pressurized admission air cylinder (105), the exhaust port (4) remaining closed during this intake air introduction phase (105), the intake air forming a lamination layer (9) ) pushing said burnt gases (8) towards said exhaust port (4).
2. Procédé de pilotage (100) selon la revendication 1 précédente caractérisé en ce que l'ajustement de la pression desdits gaz brûlés à une valeur inférieure à ladite pression d'air d'admission (103) est réalisé via l'ouverture d'une soupape de décharge à débit restreint (7). 2. Control method (100) according to claim 1, characterized in that the adjustment of the pressure of said flue gases to a value lower than said intake air pressure (103) is achieved via the opening of a restricted flow relief valve (7).
3. Procédé de pilotage (100) selon la revendication 2 précédente caractérisé en ce qu'il comporte une étape de fermeture de la soupape de décharge (104) dès lors que les gaz brûlés (8) ont une pression inférieure à la pression d'air d'admission. 3. Control method (100) according to claim 2, characterized in that it comprises a step of closing the discharge valve (104) when the flue gases (8) have a pressure lower than the pressure of intake air.
4. Procédé de pilotage (100) selon l'une quelconque des revendications 1 à 3 précédentes caractérisé en ce que dès lors que la pression contenue dans ledit cylindre moteur (2) formée par la couche de stratification (9) et les gaz brûlés (8) est sensiblement égale à la valeur de la pression d'air d'admission, le procédé comporte une étape d'ouverture du port d'échappement (106), l'introduction d'air d'admission pressurisé dans le cylindre moteur (2) se poursuivant. 4. Control method (100) according to any one of claims 1 to 3, characterized in that since the pressure contained in said engine cylinder (2) formed by the lamination layer (9) and the flue gases ( 8) is substantially equal to the value of the intake air pressure, the method comprises a step of opening the exhaust port (106), the introduction of pressurized intake air into the engine cylinder ( 2) continuing.
5. Procédé de pilotage (100) selon la revendication 1 caractérisé en ce que l'ajustement de la pression des gaz brûlés à une valeur inférieure à la pression d'air d'admission (103) est réalisé par l'ouverture du port d'échappement (4) et la création d'une contre-pression en début de ladite ouverture du port d'échappement (4) afin de limiter le débit d'échappement des gaz brûlés. 5. Control method (100) according to claim 1 characterized in that the adjustment of the pressure of the burned gases to a value lower than the intake air pressure (103) is achieved by opening the port of exhaust (4) and the creation of a back-pressure at the beginning of said opening of the exhaust port (4) in order to limit the exhaust flow rate of the burnt gases.
6. Procédé de pilotage (100) selon l'une quelconque des revendications 4 ou 5 précédentes caractérisé en ce qu'il comporte l'étape supplémentaire de fermeture du port d'échappement (108) lorsque la totalité des gaz brûlés (8) est échappée du cylindre moteur (2). 6. Control method (100) according to any one of claims 4 or 5 preceding characterized in that it comprises the additional step of closing the exhaust port (108) when all the burnt gases (8) is escaping from the driving cylinder (2).
7. Procédé de pilotage (100) selon l'une quelconque des revendications précédentes caractérisé en ce que la pression des gaz brûlés ajustée est de l'ordre de 150 mbar inférieure à la pression d'air d'admission. 7. A control method (100) according to any one of the preceding claims characterized in that the adjusted flue gas pressure is of the order of 150 mbar less than the intake air pressure.
8. Moteur deux-temps à combustion interne (1 ) comportant : 8. Two-stroke internal combustion engine (1) comprising:
- un cylindre moteur (2) présentant un axe longitudinal X,  a driving cylinder (2) having a longitudinal axis X,
- un piston (3) disposé dans ledit cylindre moteur (2), ledit piston (3) étant apte à effectuer un déplacement selon ledit axe longitudinal X, a piston (3) disposed in said driving cylinder (2), said piston (3) being able to move along said longitudinal axis X,
- un port d'échappement (4) des gaz brûlés, an exhaust port (4) for the flue gases,
- des moyens de pressurisation d'air d'admission (5),  - Intake air pressurizing means (5),
- un port d'admission (6) d'air pressurisé dans ledit cylindre moteur (2), ledit moteur (1 ) étant caractérisé en ce qu'il comporte en outre une soupape de décharge (7) à débit restreint dont l'ouverture permet l'ajustement de la pression des gaz brûlés contenus dans ledit cylindre moteur à une valeur inférieure à la pression d'air d'admission. an intake port (6) of pressurized air in said engine cylinder (2), said engine (1) being characterized in that it further comprises a discharge valve (7) with a restricted flow rate, the opening of which allows adjusting the pressure of the burnt gases contained in said engine cylinder to a value lower than the intake air pressure.
EP14755865.4A 2013-07-23 2014-07-21 Method for controlling a two-stroke internal combustion engine Withdrawn EP3025038A1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
FR1357218A FR3009025B1 (en) 2013-07-23 2013-07-23 METHOD FOR CONTROLLING AN INTERNAL COMBUSTION TWO-STROKE ENGINE
PCT/FR2014/051877 WO2015011390A1 (en) 2013-07-23 2014-07-21 Method for controlling a two-stroke internal combustion engine

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US3707952A (en) * 1970-08-20 1973-01-02 A Knebel Compression release mechanism for two stroke engines used to brake a vehicle
US4732124A (en) * 1986-06-12 1988-03-22 Toyota Jidosha Kabushiki Kaisha Two-cycle internal combustion engine
US4993372A (en) * 1989-10-19 1991-02-19 Constantin Mott Two stroke internal combustion engine with decompression valve
US5870982A (en) * 1997-11-12 1999-02-16 Strawz; Frank T. Intake valve of a supercharged two stroke engine
US8893672B2 (en) * 2008-11-16 2014-11-25 Dana R. Allen Internal-combustion engine with reduced pollutants
WO2013130661A1 (en) * 2012-02-27 2013-09-06 Sturman Digital Systems, Llc Variable compression ratio engines and methods for hcci compression ignition operation

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FR3009025B1 (en) 2017-12-29
US20160177812A1 (en) 2016-06-23
CA2919141A1 (en) 2015-01-29
FR3009025A1 (en) 2015-01-30
WO2015011390A1 (en) 2015-01-29

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