EP0786045A1 - Two-stroke engine comprising an enhanced injection device and associated injection method - Google Patents

Two-stroke engine comprising an enhanced injection device and associated injection method

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Publication number
EP0786045A1
EP0786045A1 EP95924382A EP95924382A EP0786045A1 EP 0786045 A1 EP0786045 A1 EP 0786045A1 EP 95924382 A EP95924382 A EP 95924382A EP 95924382 A EP95924382 A EP 95924382A EP 0786045 A1 EP0786045 A1 EP 0786045A1
Authority
EP
European Patent Office
Prior art keywords
valve
opening
pressure
cylinder
capacity
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.)
Granted
Application number
EP95924382A
Other languages
German (de)
French (fr)
Other versions
EP0786045B1 (en
Inventor
Pierre Duret
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 EP0786045A1 publication Critical patent/EP0786045A1/en
Application granted granted Critical
Publication of EP0786045B1 publication Critical patent/EP0786045B1/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
    • F02M69/00—Low-pressure fuel-injection apparatus ; Apparatus with both continuous and intermittent injection; Apparatus injecting different types of fuel
    • F02M69/08—Low-pressure fuel-injection apparatus ; Apparatus with both continuous and intermittent injection; Apparatus injecting different types of fuel characterised by the fuel being carried by compressed air into main stream of combustion-air
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01L—CYCLICALLY OPERATING VALVES FOR MACHINES OR ENGINES
    • F01L9/00—Valve-gear or valve arrangements actuated non-mechanically
    • F01L9/10—Valve-gear or valve arrangements actuated non-mechanically by fluid means, e.g. hydraulic
    • F01L9/16—Pneumatic means
    • 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
    • F02B33/00—Engines characterised by provision of pumps for charging or scavenging
    • F02B33/02—Engines with reciprocating-piston pumps; Engines with crankcase pumps
    • F02B33/04—Engines with reciprocating-piston pumps; Engines with crankcase pumps with simple crankcase pumps, i.e. with the rear face of a non-stepped working piston acting as sole pumping member in co-operation with the crankcase
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
    • F02M67/00—Apparatus in which fuel-injection is effected by means of high-pressure gas, the gas carrying the fuel into working cylinders of the engine, e.g. air-injection type
    • F02M67/02—Apparatus in which fuel-injection is effected by means of high-pressure gas, the gas carrying the fuel into working cylinders of the engine, e.g. air-injection type the gas being compressed air, e.g. compressed in pumps
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
    • F02M69/00—Low-pressure fuel-injection apparatus ; Apparatus with both continuous and intermittent injection; Apparatus injecting different types of fuel
    • F02M69/10—Low-pressure fuel-injection apparatus ; Apparatus with both continuous and intermittent injection; Apparatus injecting different types of fuel peculiar to scavenged two-stroke engines, e.g. injecting into crankcase-pump chamber

Definitions

  • the present invention relates to the field of two-stroke engines with controlled pneumatic injection.
  • the present invention relates to the command and control of pneumatic fuel injection, in two-stroke single-cylinder or multi-cylinder engines.
  • a conventional way of controlling pneumatic injection is to connect the valves to a camshaft.
  • This purely mechanical solution is not very flexible to use since each cam requires a precise movement of a valve and moreover, the camshaft supporting several cams, it is a given general movement which is imposed from the outset of all the cams.
  • This technology therefore generates a general command common to all the valves of the camshaft. Adjustment is difficult and a problem with one of the cams and / or the valves can have repercussions on all the other parts involved.
  • More flexible control systems are known, based in particular on pressure variations between different chambers cooperating with the movement of the valve.
  • French patents FR 2 656 653 and FR 2 656 656 describe two-stroke multi-cylinder engines in which the pneumatic fuel injection is carried out by means of pressure differences between different chambers.
  • This prior art specifically relates to engines having several cylinders since the pressure differences are created thanks to the angular offset existing between the cycles of the different cylinders.
  • the objective of the present invention is to simplify this technology and above all to be able to apply it to single-cylinder engines, which the above-mentioned prior art in no way allows.
  • each cylinder operates, as far as its pneumatic injection is concerned, independently, autonomously, without particular connections between cylinders.
  • a multi-cylinder engine according to the invention must therefore be considered as an engine having juxtaposed autonomous cylinders.
  • the object of the invention is to use the different pressure variations inherent in the operation of a cylinder to actuate automatically a pneumatic fuel injection device in this cylinder.
  • a control means mechanical such as a camshaft.
  • the present invention relates to a two-stroke engine comprising at least:
  • a cylinder in which a piston moves and one end of which communicates with a pump housing through which the engine crankshaft passes, - a pressurized capacity opening at one end into the combustion chamber of the cylinder, at least one valve ensuring intermittent sealing between the chamber and the capacity, - means intended to carburize the gas passing through said capacity,
  • the engine according to the invention further comprises:
  • the capacity opens at its other end into an opening in the pump housing, a means for controlling said opening being also provided.
  • the motor according to the invention may further comprise means intended to intermittently seal said connecting means in order to delay the pressure drop in the connecting means, that is to say the opening of the valve.
  • said intermittent sealing means may comprise a flange placed in the pump housing, linked in rotation to the crankshaft of the engine and comprising at least one peripheral recess.
  • the engine may further comprise control means related to the closing of the valve.
  • said control means comprise a means of connection between the other of said chambers and said pump housing, said means being arranged so that it is intermittently closed on the pump housing side, said means alternately making it possible to amplify the opening of the valve and to assist in its closing.
  • connection means opens out through an opening in the lower part of the cylinder so as to be alternately covered and uncovered by the piston.
  • the intermittent closure of the connection means is produced by a specific flange linked to the crankshaft.
  • the engine may further comprise an elastic return element of the valve on its seat, which cooperates with said flexible membrane.
  • the present invention relates to a method for controlling the opening of a fuel mixture injection valve in an engine as defined above, which consists in controlling the opening of said valve as soon as possible when the pressure P ⁇ in a connection between the chamber and the pump housing becomes lower than the pressure Ps in a capacity.
  • FIG. 1 is a sectional view of an assisted valve that can operate according to the invention
  • FIG. 2 is a simplified longitudinal section of a cylinder of a two-stroke engine according to an embodiment of the invention
  • FIG. 3 is a diagram showing the different control pressures of a valve according to a first embodiment of the invention, as a function of the angle of rotation of the crankshaft;
  • FIG. 4 is a diagram showing the different control pressures of a valve according to another mode of operation of the invention, as a function of the angle of rotation of the crankshaft;
  • FIG. 5 is a simplified longitudinal section of a cylinder of a two-stroke engine according to yet another embodiment of the invention.
  • FIG. 6 is a diagram showing the different control pressures of a valve in an engine according to Figure 5, depending on the angle of rotation of the crankshaft.
  • FIG. 1 shows a device for controlling injection into a cylinder of a two-stroke engine, generally designated by the reference 82.
  • Such an injection device of the assisted automatic valve type can in particular be associated with each of the cylinders of a two-stroke engine as shown in FIGS. 2 and 4.
  • the device d 'assisted automatic valve injection 82 is fixed to the cylinder head of the engine at the level of the corresponding cylinder.
  • the injection device 82 includes a fuel supply air (or gas) channel 84 machined in the cylinder head 83 and opening, through an opening 85, into the interior volume of the cylinder.
  • the channel 84 is connected to a pipe 87 into which the end of a metering and / or fuel injection means 88 opens.
  • the valve 86 for closing the end of the channel 84 opening into the cylinder has a head that comes to bear, in the valve closed position as shown in FIG. 1, in the opening 85 constituting a valve seat.
  • the stem (not referenced) of the valve 86 is connected at its other end to a flexible membrane 89 fixed along its entire periphery and sealingly, between two parts of the wall of a casing 90 of the injection means 82.
  • the casing 90 consists of an upper hollow half-casing 90a and a lower half-casing 90b connected together and at the periphery of the membrane 89 by means of external flanges constituting assembly flanges of the casing 90.
  • the upper part 90a of the casing 90 has a pipe 91 opening into its internal volume and the lower part 90b of the casing 90 which is tightly fixed on the cylinder head 83 above the opening 85 of the channel 84 has a duct 92 opening in its interior volume.
  • a return spring 93 is preferably interposed between the flexible membrane 89 or the end of the valve stem 86 and the upper surface of the cylinder head 83.
  • An assisted control valve injection device as shown in FIG. 1 is known from the prior art and makes it possible to ensure the opening and closing control of the valve determining the start and the end of the injection. in the cylinder, by adjusting the differential pressure between the chambers 95a and 95b delimited in the casing 90 by the membrane 89.
  • the pipes 91 and 92 can be connected to pressure-regulated gas supply devices making it possible to ensure the opening or closing of the valve 86 by differential pressure in the chambers 95a and 95b as well as by differential pressure between chamber 84 and the cylinder.
  • Figure 2 shows an embodiment of the invention according to which the injection device 82 is part of an engine including a cylinder 1 1 1 is shown in longitudinal section.
  • the cylinder 1 1 1 comprises a combustion chamber 1 13 in which a piston 1 12 moves, communicating at its lower part with a pump casing 115.
  • the pump housing 1 15 comprises, conventionally, an air intake nozzle 1 19 on which a valve 120 is placed.
  • the fresh air introduced into the casing 1 15 and compressed by the piston 1 12 is injected into the combustion chamber 1 13 of the cylinder 1 11, by means of transfer conduits such as 121 opening into the cylinder chamber through openings 122.
  • the burnt gases are evacuated from the chamber 1 13 by a pipe 123.
  • the conduit 87 is pressurized either by an external source or by the fact that this conduit opens at its end 127 opposite to that which opens into the injection device 82, directly into the pump housing 1 15.
  • the opening 127 is preferably controlled by a non-return valve or any other means capable of closing this opening as soon as the pressure in the pump housing 1 becomes less than the pressure in the conduit 87 which is therefore used as a capacity for pressure storage.
  • the pipe 92 which communicates by one of its ends with the chamber 95b of the injection device 82, opens according to the invention into the pump housing 1 15 by its other end. Therefore, the pressure P ⁇ in the chamber 95b follows the pressure variations in the pump housing 1 15 of the cylinder 1 1 1.
  • the pressure PA in chamber 95a can be atmospheric pressure or another rather constant pressure.
  • the cylinder pressure PI is always greater than the pressure Ps in the capacity 87.
  • the valve 86 therefore does not open.
  • valve 86 should open if the engine was not in accordance with the invention. This would therefore involve opening the valve and starting injection as soon as the transfers open, that is to say very early in the cycle.
  • the presence of the pipe 92 according to the invention allows the chamber 95b to remain at a pressure P ⁇ greater than the pressure PS for another approximately 30 ° crankshaft.
  • the opening of the valve 86 will be delayed at least until the time when the casing pressure P ⁇ becomes lower than the capacity pressure PS -
  • the injection I therefore begins, according to this configuration and under the operating conditions of the engine of FIG. 3, towards
  • the invention therefore makes it possible to significantly delay the start of the injection of fuel mixture, in a simple and reliable manner.
  • the operation of the engine is improved since said delay makes it possible to limit the unburnt fuel directly discharged to the exhaust.
  • FIG 2 further appears a flange 1 16 linked to the crankshaft.
  • This element which is not necessarily present in the pump housing 1 15, however, makes it possible to obtain the following additional characteristic: a selective closure of the connection 92.
  • the flange 1 16 is cut at the periphery so that only a given angular sector closes the orifice 92a of the connection 92, therefore during a certain angular range given to a motor cycle.
  • the pressure P ⁇ in the conduit 92 and the chamber 95b is stored at a given value taken before the pressure drop in the pump housing, that is to say taken for example at the time opening of OT transfers.
  • the flange 116 here makes it possible to close the orifice 92a until the desired moment to trigger the opening of the valve, that is to say for example up to the PMB according to FIG. 4. Selective sealing of the conduit 92 allows therefore store the casing pressure P ⁇ for a period of time determined by the value of the angular sector of the flange 1 16.
  • the delay in opening the valve is greater here than in the previous case since the opening begins around 180 ° crankshaft, while in the previous case
  • this opening was around 165 crankshaft; it should be recalled that without the invention the valve is opened when the pressure in the cylinder becomes lower than the pressure in the conduit 87, that is to say in the case envisaged, around 130 ° crankshaft.
  • the flange 1 16 allows better control of the opening of the valve 86 since, as it appears in particular in FIG. 4, the opening of the conduit 92 being frank, the pressure drop is just as much so that the opening is also better controlled since it no longer depends on the decrease in the pressure in the pump housing, a decrease which is not always as rapid depending on the load conditions and engine speed, According to this embodiment of the invention, the opening of the valve simply depends on the opening of the conduit 92 by the flange 1 16.
  • Another improvement of the present invention can consist in communicating, intermittently, the chamber 95a with the pump housing 1 15.
  • such an embodiment of the invention makes it possible in particular to obtain faster opening by amplifying the movement of the valve, as well as '' an improvement in the closing of the valve.
  • a certain inertia of the automatic valve has sometimes been observed, which slows down its opening.
  • FIG. 5 shows an embodiment similar to the previous ones but according to which the motor further comprises a connection 91 between the chamber 95a and the pump housing 1 15.
  • the connection 91 opens out through a light 91a located in the part lower of the cylinder, just above the pump housing.
  • the connection 91 is put in communication with the pump casing when the piston 1 12 passes above said light 9 1 a, that is to say intermittently.
  • connection 91 which is therefore controlled by the piston skirt can be closed from the opening of the transfer lights 122 until the closing of these same lights, that is to say symmetrically with respect to the bottom dead center .
  • another phasing can be obtained, for example an opening and a closing which are not symmetrical with respect to the bottom dead center, thanks to a flange linked to the crankshaft. This flange may or may not be the same as that which controls the connection 92.
  • FIG. 6 illustrates the operation of this embodiment of the invention.
  • the valve 86 is then held in its seat by the difference between the pressure PI in cylinder 1 13 and pressure Ps in capacity 87, possibly assisted by a return spring.
  • the light 92a can optionally be closed simultaneously by the flange 116 as shown in Figure 6, but this is not mandatory.
  • the start of the valve opening control is located as soon as the pressure P ⁇ becomes lower than the pressure Ps in the capacity.
  • the pressure drop P ⁇ can occur either naturally, that is to say without the flange 1 16, or at the opening of the light 92a by the flange 1 16.
  • the pressure PA which becomes higher than the pressure P ⁇ makes it possible to amplify the force necessary for the opening of the valve by means of an adequate ratio between the surface of the membrane 89 and that of the valve 86.
  • the opening of the valve 86 is therefore faster and its amplitude can also be increased thanks to this effect.

Abstract

PCT No. PCT/FR95/00866 Sec. 371 Date Mar. 10, 1997 Sec. 102(e) Date Mar. 10, 1997 PCT Filed Jun. 28, 1995 PCT Pub. No. WO96/07817 PCT Pub. Date Mar. 14, 1996The present invention relates to a two-stroke engine comprising at least: a cylinder (111) in which a piston (112) moves and one end of which communicates with a pump crankcase (115) crossed through by the crankshaft (114) of the engine, a capacity under pressure (87) opening at one end into the combustion chamber (113) of the cylinder (111), at least one valve (86) ensuring an intermittent sealing between the chamber (113) and the capacity (87), a means (88) intended for carburetting the gas passing in said capacity (87), a means for controlling the opening of said valve (86) comprising a supple membrane (89) separating two chambers (95a, 95b) and connected to the rod of the valve. The engine according to the invention further comprises a liking means (92) between one (95b) of said chambers and the pump crankcase (115) of said cylinder, allowing notably the opening of the valve (86) to be activated as soon as possible when the pressure PB in the chamber (95b) becomes lower than the pressure PS in said capacity (87).

Description

MOTEUR DEUX TEMPS À DIS POSITIF D 'INJECTION AMÉLIORÉ ET PROCÉDÉ D'INJECTION ASSOCIÉIMPROVED TWO STROKE ENGINE WITH INJECTION AND INJECTION METHOD THEREOF
La présente invention concerne le domaine des moteurs à deux temps à injection pneumatique commandée.The present invention relates to the field of two-stroke engines with controlled pneumatic injection.
Plus précisément la présente invention a trait à la commande et au contrôle de l'injection pneumatique de carburant, dans des moteurs deux temps monocylindre ou multicylindres. Une façon conventionnelle de commander l'injection pneumatique consiste à relier les soupapes à un arbre à came. Cette solution purement mécanique s'avère d'utilisation peu souple puisque chaque came impose un mouvement précis d'une soupape et de plus, l'arbre à came supportant plusieurs cames, c'est un mouvement général donné qui est imposé dès l'origine de l'ensemble des cames. Cette technologie génère donc une commande générale commune à toutes les soupapes de l'arbre à came. Le réglage est difficile et un problème sur l'une des cames et/ou des soupapes peut avoir des répercutions sur l'ensemble des autres pièces mises en jeu.More specifically, the present invention relates to the command and control of pneumatic fuel injection, in two-stroke single-cylinder or multi-cylinder engines. A conventional way of controlling pneumatic injection is to connect the valves to a camshaft. This purely mechanical solution is not very flexible to use since each cam requires a precise movement of a valve and moreover, the camshaft supporting several cams, it is a given general movement which is imposed from the outset of all the cams. This technology therefore generates a general command common to all the valves of the camshaft. Adjustment is difficult and a problem with one of the cams and / or the valves can have repercussions on all the other parts involved.
Des systèmes de commande plus souples sont connus, basés notamment sur des variations de pressions entre différentes chambres coopérant avec le mouvement de la soupape.More flexible control systems are known, based in particular on pressure variations between different chambers cooperating with the movement of the valve.
Ainsi, les brevets français FR 2 656 653 et FR 2 656 656 décrivent des moteurs deux temps multicylindre dans lesquels l'injection pneumatique de carburant est réalisée grâce à des différences de pression entre différentes chambres. Cet art antérieur concerne spécifiquement des moteurs ayant plusieurs cylindres puisque les différences de pression sont créées grâce au décalage angulaire existant entre les cycles des différents cylindres.Thus, French patents FR 2 656 653 and FR 2 656 656 describe two-stroke multi-cylinder engines in which the pneumatic fuel injection is carried out by means of pressure differences between different chambers. This prior art specifically relates to engines having several cylinders since the pressure differences are created thanks to the angular offset existing between the cycles of the different cylinders.
L'objectif de la présente invention est de simplifier cette technologie et surtout de pouvoir l'appliquer à des moteurs monocylindre, ce que ne permet nullement l'art antérieur précité.The objective of the present invention is to simplify this technology and above all to be able to apply it to single-cylinder engines, which the above-mentioned prior art in no way allows.
La présente invention peut cependant s'appliquer à des moteurs multi-cylindre mais à la différence de l'art antérieur, dans ce cas l'injection fonctionne indépendamment dans chaque cylindre. Autrement dit selon la présente invention, chaque cylindre fonctionne, pour ce qui concerne son injection pneumatique, d'une façon indépendante , autonome, sans connections particulières entre cylindres . Un moteur multicylindre selon l'invention doit donc être considéré comme un moteur ayant des cylindres autonomes juxtaposés.The present invention can however be applied to multi-cylinder engines but unlike the prior art, in this case the injection works independently in each cylinder. In other words according to the present invention, each cylinder operates, as far as its pneumatic injection is concerned, independently, autonomously, without particular connections between cylinders. A multi-cylinder engine according to the invention must therefore be considered as an engine having juxtaposed autonomous cylinders.
Enoncé d'une façon générale, l'objet de l'invention est d'utiliser les différentes variations de pression inhérentes au fonctionnement d'un cyli ndre pour actionner de façon automatique un dispositif d'injection pneumatique de carburant dans ce cylindre. En d'autres termes il s'agit, selon l'invention, de commander l'ouverture et la fermeture d'une soupape de façon automatique à chaque tour moteur, à des instants précis et déterminés, sans avoir recours à un moyen de commande mécanique tel qu'un arbre à cames.Generally stated, the object of the invention is to use the different pressure variations inherent in the operation of a cylinder to actuate automatically a pneumatic fuel injection device in this cylinder. In other words, it is a question, according to the invention, of controlling the opening and closing of a valve automatically at each engine revolution, at precise and determined times, without resorting to a control means. mechanical such as a camshaft.
Il ressort de ce qui précède que le réglage et la commande de l'injection selon l'invention est individuel, au niveau de chaque cylindre, ce qui simplifie la solution conventionnelle multicylindre.It emerges from the above that the adjustment and control of the injection according to the invention is individual, at the level of each cylinder, which simplifies the conventional multicylinder solution.
Ainsi la présente invention concerne un moteur à deux temps comportant au moins :Thus the present invention relates to a two-stroke engine comprising at least:
- un cylindre dans lequel se déplace un piston et dont l'une des extrémités communique avec un carter-pompe traversé par le vilebrequin du moteur, - une capacité sous pression débouchant à une extrémité dans la chambre de combustion du cylindre, au moins une soupape assurant l'obturation intermittente entre la chambre et la capacité, - un moyen destiné à carburer le gaz passant dans ladite capacité,- a cylinder in which a piston moves and one end of which communicates with a pump housing through which the engine crankshaft passes, - a pressurized capacity opening at one end into the combustion chamber of the cylinder, at least one valve ensuring intermittent sealing between the chamber and the capacity, - means intended to carburize the gas passing through said capacity,
- un moyen de commande de l'ouverture de ladite soupape comprenant une membrane souple séparant deux chambres et reliée à la tige de la soupape, Le moteur selon l'invention comprend en outre :a means for controlling the opening of said valve comprising a flexible membrane separating two chambers and connected to the valve stem, the engine according to the invention further comprises:
- un moyen de liaison entre l'une desdites chambres et le carter- pompe dudit cylindre, permettant notamment de déclencher l'ouverture de la soupape au plus tôt quand la pression Pβ dans la chambre devient inférieure à la pression Ps dans ladite capacité.a means of connection between one of said chambers and the crankcase pump of said cylinder, making it possible in particular to trigger the opening of the valve as soon as possible when the pressure Pβ in the chamber becomes lower than the pressure Ps in said capacity.
Préférentiellement, la capacité débouche par son autre extrémité dans une ouverture du carter-pompe, un moyen de contrôle de ladite ouverture étant par ailleurs prévu.Preferably, the capacity opens at its other end into an opening in the pump housing, a means for controlling said opening being also provided.
De façon particulière, le moteur selon l'invention peut comprendre en outre, un moyen destiné à obturer de façon intermittente ledit moyen de liaison afin de retarder la chute de pression dans le moyen de liaison c'est-à-dire l'ouverture de la soupape.In particular, the motor according to the invention may further comprise means intended to intermittently seal said connecting means in order to delay the pressure drop in the connecting means, that is to say the opening of the valve.
Plus précisément ledit moyen d'obturation intermittente peut comprendre un flasque placé dans le carter-pompe, lié en rotation au vilebrequin du moteur et comprenant au moins un évidement périphérique.More precisely, said intermittent sealing means may comprise a flange placed in the pump housing, linked in rotation to the crankshaft of the engine and comprising at least one peripheral recess.
Conformément à l'une de ses caractéristiques, le moteur peut comprendre en outre des moyens de contrôle liés à la fermeture de la soupape.According to one of its characteristics, the engine may further comprise control means related to the closing of the valve.
Avantageusement, lesdits moyens de contrôle comprennent un moyen de connection entre l'autre desdites chambres et ledit carter-pompe, ledit moyen étant agencé de telle sorte qu'il est obturé de façon intermittente coté carter-pompe, ledit moyen permettant alternativement d'amplifier l'ouverture de la soupape et d'aider à sa fermeture.Advantageously, said control means comprise a means of connection between the other of said chambers and said pump housing, said means being arranged so that it is intermittently closed on the pump housing side, said means alternately making it possible to amplify the opening of the valve and to assist in its closing.
Selon un mode de réalisation de l'invention ledit moyen de connection débouche par une ouverture dans la partie inférieure du cylindre de façon à être alternativement couverte et découverte par le piston.According to one embodiment of the invention, said connection means opens out through an opening in the lower part of the cylinder so as to be alternately covered and uncovered by the piston.
Selon l'autre mode de réalisation de l'invention l'obturation intermittente du moyen de connection est réalisé par un flasque spécifique lié au vilebrequin. Sans sortir du cadre de l'invention, le moteur peut comprendre en outre un élément élastique de rappel de la soupape sur son siège, qui coopère avec ladite membrane souple.According to the other embodiment of the invention, the intermittent closure of the connection means is produced by a specific flange linked to the crankshaft. Without departing from the scope of the invention, the engine may further comprise an elastic return element of the valve on its seat, which cooperates with said flexible membrane.
La présente invention concerne un procédé de contrôle de l'ouverture d'une soupape d'injection de mélange carburé dans un moteur tel que défini ci-avant, qui consiste à commander l'ouverture de ladite soupape au plus tôt lorsque la pression Pβ dans une liaison chambre-carter pompe devient inférieure à la pression Ps dans une capacité.The present invention relates to a method for controlling the opening of a fuel mixture injection valve in an engine as defined above, which consists in controlling the opening of said valve as soon as possible when the pressure Pβ in a connection between the chamber and the pump housing becomes lower than the pressure Ps in a capacity.
La présente invention sera mieux comprise, ses caractéristiques, avantages et modes de réali sation seront davantage compris à la lecture de la description qui va suivre, faite à titre illustratif et nullement limitatif en référence aux figures annexées selon lesquelles :The present invention will be better understood, its characteristics, advantages and embodiments will be better understood on reading the description which follows, given by way of illustration and in no way limiting with reference to the appended figures according to which:
- La figure 1 est en vue en coupe d'une soupape assistée pouvant fonctionner selon l'invention;- Figure 1 is a sectional view of an assisted valve that can operate according to the invention;
- La figure 2 est une coupe longitudinale simplifiée d'un cylindre d'un moteur à deux temps selon un mode de réalisation de l'invention;- Figure 2 is a simplified longitudinal section of a cylinder of a two-stroke engine according to an embodiment of the invention;
- La figure 3 est un diagramme montrant les différentes pressions de commande d'une soupape selon un premier mode de réalisation de l'invention, en fonction de l'angle de rotation du vilebrequin;- Figure 3 is a diagram showing the different control pressures of a valve according to a first embodiment of the invention, as a function of the angle of rotation of the crankshaft;
- La figure 4 est un diagramme montrant les différentes pressions de commande d'une soupape selon un autre mode de fonctionnement de l'invention, en fonction de l'angle de rotation du vilebrequin;- Figure 4 is a diagram showing the different control pressures of a valve according to another mode of operation of the invention, as a function of the angle of rotation of the crankshaft;
- La figure 5 est une coupe longitudinale simplifiée d'un cylindre d'un moteur à deux temps selon encore un autre mode de réalisation de l'invention;- Figure 5 is a simplified longitudinal section of a cylinder of a two-stroke engine according to yet another embodiment of the invention;
- La figure 6 est un diagramme montran t les différentes pressions de commande d'une soupape dans un moteur selon la figure 5, en fonction de l'angle de rotation du vilebrequin.- Figure 6 is a diagram showing the different control pressures of a valve in an engine according to Figure 5, depending on the angle of rotation of the crankshaft.
Sur la figure 1 est représenté un dispositif de commande d'injection dans un cylindre d'un moteur à deux temps, désigné de manière générale par le repère 82.FIG. 1 shows a device for controlling injection into a cylinder of a two-stroke engine, generally designated by the reference 82.
Un tel dispositif d'injection du type à soupape automatique assistée peut notamment être associé à chacun des cylindres d'un moteur à deux temps tel que représenté sur les figures 2 et 4. Sur les figures 2 et 4, on voit que le dispositif d'injection à soupape automatique assistée 82 est fixé sur la culasse du moteur au niveau du cylindre correspondant.Such an injection device of the assisted automatic valve type can in particular be associated with each of the cylinders of a two-stroke engine as shown in FIGS. 2 and 4. In FIGS. 2 and 4, it can be seen that the device d 'assisted automatic valve injection 82 is fixed to the cylinder head of the engine at the level of the corresponding cylinder.
Comme il est visible sur la figure 1 , le dispositif d'injection 82 comporte un canal 84 d'alimentation en air (ou gaz) carburé usiné dans la culasse 83 et débouchant, par une ouverture 85, dans le volume intérieur du cylindre. Le canal 84 est relié à une canalisation 87 dans laquelle débouche l'extrémité d'un moyen de dosage et/ou d'injection de carburant 88.As can be seen in FIG. 1, the injection device 82 includes a fuel supply air (or gas) channel 84 machined in the cylinder head 83 and opening, through an opening 85, into the interior volume of the cylinder. The channel 84 is connected to a pipe 87 into which the end of a metering and / or fuel injection means 88 opens.
La soupape 86 de fermeture de l'extrémité du canal 84 débouchant dans le cylindre comporte une tête venant en appui, dans la position de fermeture de la soupape comme représenté sur la figure 1 , dans l'ouverture 85 constituant un siège de soupape. La tige (non référencée) de la soupape 86 est reliée à son autre extrémité à une membrane souple 89 fixée suivant toute sa périphérie et de manière étanche, entre deux parties de la paroi d'un carter 90 du moyen d'injection 82.The valve 86 for closing the end of the channel 84 opening into the cylinder has a head that comes to bear, in the valve closed position as shown in FIG. 1, in the opening 85 constituting a valve seat. The stem (not referenced) of the valve 86 is connected at its other end to a flexible membrane 89 fixed along its entire periphery and sealingly, between two parts of the wall of a casing 90 of the injection means 82.
De manière préférentielle, le carter 90 est constitué d'une demi-enveloppe creuse supérieure 90a et d'une demi-enveloppe inférieure 90b reliées entre elles et à la périphérie de la membrane 89 par l'intermédiaire de rebords externes constituant des flasques d'assemblage du carter 90.Preferably, the casing 90 consists of an upper hollow half-casing 90a and a lower half-casing 90b connected together and at the periphery of the membrane 89 by means of external flanges constituting assembly flanges of the casing 90.
La partie supérieure 90a du carter 90 comporte une conduite 91 débouchant dans son volume intérieur et la partie inférieure 90b du carter 90 qui est fixée de manière étanche sur la culasse 83 au-dessus de l'ouverture 85 du canal 84 comporte une canalisation 92 débouchant dans son volume intérieur.The upper part 90a of the casing 90 has a pipe 91 opening into its internal volume and the lower part 90b of the casing 90 which is tightly fixed on the cylinder head 83 above the opening 85 of the channel 84 has a duct 92 opening in its interior volume.
Un ressort de rappel 93 est préférentiellement intercalé entre la membrane souple 89 ou l'extrémité de la tige de la soupape 86 et la surface supérieure de la culasse 83.A return spring 93 is preferably interposed between the flexible membrane 89 or the end of the valve stem 86 and the upper surface of the cylinder head 83.
Un dispositif d'injection à soupape à commande assistée tel que représenté sur la figure 1 est connu de l'art antérieur et permet d'assurer la commande d'ouverture et de fermeture de la soupape déterminant le début et la fin de l'injection dans le cylindre, par réglage de la pression différentielle entre les chambres 95a et 95b délimitées dans le carter 90 par la membrane 89.An assisted control valve injection device as shown in FIG. 1 is known from the prior art and makes it possible to ensure the opening and closing control of the valve determining the start and the end of the injection. in the cylinder, by adjusting the differential pressure between the chambers 95a and 95b delimited in the casing 90 by the membrane 89.
Pour cela, les conduites 91 et 92 peuvent être reliées à des dispositifs d'alimentation en gaz à pression réglée permettant d'assurer l'ouverture ou la fermeture de la soupape 86 par pression différentielle dans les chambres 95a et 95b ainsi que par pression différentielle entre la chambre 84 et le cylindre.For this, the pipes 91 and 92 can be connected to pressure-regulated gas supply devices making it possible to ensure the opening or closing of the valve 86 by differential pressure in the chambers 95a and 95b as well as by differential pressure between chamber 84 and the cylinder.
Selon l'invention, dans le cas d'un moteur à deux temps ayant un ou plusieurs cylindres et à injection pneumatique, la pression de commande dans l'une au moins des chambres 95a etAccording to the invention, in the case of a two-stroke engine having one or more cylinders and with pneumatic injection, the control pressure in at least one of the chambers 95a and
95b est produite par mise en communication de cette chambre avec le volume intérieur du carter-pompe du même cylindre du moteur.95b is produced by placing this chamber in communication with the interior volume of the pump housing of the same engine cylinder.
La figure 2 montre un mode de réalisation de l'invention selon lequel le dispositif d'injection 82 fait partie d'un moteur dont un cylindre 1 1 1 est représenté en coupe longitudinale.Figure 2 shows an embodiment of the invention according to which the injection device 82 is part of an engine including a cylinder 1 1 1 is shown in longitudinal section.
De façon classique, le cylindre 1 1 1 comporte une chambre de combustion 1 13 dans laquelle se déplace un piston 1 12 communiquant à sa partie inférieure avec un carter-pompe 115. Le carter-pompe 1 15 comporte, de manière classique un ajutage d'admission d'air 1 19 sur lequel est placé un clapet 120.Conventionally, the cylinder 1 1 1 comprises a combustion chamber 1 13 in which a piston 1 12 moves, communicating at its lower part with a pump casing 115. The pump housing 1 15 comprises, conventionally, an air intake nozzle 1 19 on which a valve 120 is placed.
L'air frais introduit dans le carter 1 15 et comprimé par le piston 1 12 est injecté dans la chambre de combustion 1 13 du cylindre 1 11 , par l'intermédiaire de conduits de transfert tels que 121 débouchant dans la chambre de cylindre par des ouvertures 122. Les gaz brûlés sont évacués de la chambre 1 13 par une conduite 123.The fresh air introduced into the casing 1 15 and compressed by the piston 1 12 is injected into the combustion chamber 1 13 of the cylinder 1 11, by means of transfer conduits such as 121 opening into the cylinder chamber through openings 122. The burnt gases are evacuated from the chamber 1 13 by a pipe 123.
Selon l'invention, le conduit 87 est mis sous pression soit par une source extérieure soit par le fait que ce conduit débouche par son extrémité 127 opposée à celle débouchant dans le dispositif 82 d'injection, directement dans le carter-pompe 1 15.According to the invention, the conduit 87 is pressurized either by an external source or by the fact that this conduit opens at its end 127 opposite to that which opens into the injection device 82, directly into the pump housing 1 15.
L'ouverture 127 est préférentiellement contrôlée par un clapet anti-retour ou tout autre moyen capable d'obturer cette ouverture dès que la pression dans le carter-pompe 1 15 devient inférieure à la pression dans le conduit 87 qui est donc utilisé comme capacité de stockage de pression.The opening 127 is preferably controlled by a non-return valve or any other means capable of closing this opening as soon as the pressure in the pump housing 1 becomes less than the pressure in the conduit 87 which is therefore used as a capacity for pressure storage.
Par ailleurs la conduite 92, qui communique par l'une de ses extrémités avec la chambre 95b du dispositif d'njection 82, débouche selon l'invention dans le carter-pompe 1 15 par son autre extrémité. De ce fait, la prssion Pβ dans la chambre 95b suit les variations de pression dans le carter-pompe 1 15 du cylindre 1 1 1 .Furthermore, the pipe 92, which communicates by one of its ends with the chamber 95b of the injection device 82, opens according to the invention into the pump housing 1 15 by its other end. Therefore, the pressure Pβ in the chamber 95b follows the pressure variations in the pump housing 1 15 of the cylinder 1 1 1.
Selon un premier mode de réalisation de l'invention, la pression PA dans chambre 95a peut être la pression atmosphérique ou une autre pression plutôt constante.According to a first embodiment of the invention, the pressure PA in chamber 95a can be atmospheric pressure or another rather constant pressure.
Le fonctionnement du dispositif d'injection selon l'invention va maintenant être expliqué en relation avec la figure 3 sur laquelle figurent en fonction de l'angle de rotation du vilebrequin les variations :The operation of the injection device according to the invention will now be explained in relation to FIG. 3 in which the variations appear as a function of the angle of rotation of the crankshaft:
- de la pression PI dans le cylindre 1 1 1 , pression représentée en trait plein,- the pressure PI in the cylinder 1 1 1, pressure shown in solid lines,
- de la pression Ps dans la capacité 87 et la chambre 84, pression représentée en traits mixtes, - de la pression Pβ dans le carter-pompe 1 15, la conduite 92 et la chambre 95b pression représentée en traits pointillés.- of the pressure Ps in the capacity 87 and the chamber 84, pressure shown in dashed lines, - Pβ pressure in the pump housing 1 15, the pipe 92 and the pressure chamber 95b shown in dotted lines.
Ainsi, selon ce mode de réalisation de l'invention, du point mort haut (PMH angle vilebrequin nul) jusqu'au voisinage (OT) de l'ouverture des lumières de transfert, la pression cylindre PI est toujours supérieure à la pression Ps dans la capacité 87. La soupape 86 ne s'ouvre donc pas.Thus, according to this embodiment of the invention, from top dead center (TDC zero crankshaft angle) to the vicinity (OT) of the opening of the transfer lights, the cylinder pressure PI is always greater than the pressure Ps in the capacity 87. The valve 86 therefore does not open.
A partir du moment où la pression cylindre Pi devient inférieure à la pression Ps , la soupape 86 devrait s'ouvrir si le moteur n'était pas conforme à l'invention . Ceci impliquerait donc une ouverture de la soupape et un début d'injection dès l'ouverture des transferts c'est-à-dire très tôt dans le cycle.From the moment when the cylinder pressure Pi becomes lower than the pressure Ps, the valve 86 should open if the engine was not in accordance with the invention. This would therefore involve opening the valve and starting injection as soon as the transfers open, that is to say very early in the cycle.
La présence de la conduite 92 selon l'invention permet à la chambre 95b de rester à une pression Pβ supérieure à la pression PS pendant encore environ 30° vilebrequin.The presence of the pipe 92 according to the invention allows the chamber 95b to remain at a pressure Pβ greater than the pressure PS for another approximately 30 ° crankshaft.
L'effet de la pression Pβ sera alors prédominant par rapport à celui de la pression Ps (si l'on considère les sections de la membrane 89 et de la soupape 86 comme équivalentes).The effect of the pressure Pβ will then be predominant compared to that of the pressure Ps (if we consider the sections of the membrane 89 and of the valve 86 as equivalent).
Ainsi, avec un tel dimensionnement, l'ouverture de la soupape 86 sera retardée au moins jusqu'au moment où la pression carter Pβ devient inférieure à la pression capacité PS -Thus, with such a dimensioning, the opening of the valve 86 will be delayed at least until the time when the casing pressure Pβ becomes lower than the capacity pressure PS -
Si la membrane 89 présente une section supérieure, l'ouverture de la soupape sera encore retardée.If the membrane 89 has an upper section, the opening of the valve will be further delayed.
L'injection I débute donc, selon cette configuration et dans les conditions de fonctionnement du moteur de la figure 3, versThe injection I therefore begins, according to this configuration and under the operating conditions of the engine of FIG. 3, towards
165° vilebrequin, pour finir quand la pression cylindre P l devient supérieure à la pression capacité Ps , c'est-à-dire aux environ de 270° vilebrequin.165 ° crankshaft, to finish when the cylinder pressure P l becomes higher than the capacity pressure Ps, that is to say around 270 ° crankshaft.
L'invention permet donc de retarder de façon significative le début de l'injection de mélange carburé, et ce d'une façon simple et fiable. Le fonctionnement du moteur se trouve amélioré puisque ledit retard permet de limiter le carburant imbrûlé directement rejeté à l'échappement.The invention therefore makes it possible to significantly delay the start of the injection of fuel mixture, in a simple and reliable manner. The operation of the engine is improved since said delay makes it possible to limit the unburnt fuel directly discharged to the exhaust.
Sur la figure 2 apparaît en outre un flasque 1 16 lié au vilebrequin. Cet élément, qui n'est pas obligatoirement présent dans le carter-pompe 1 15 , permet cependant d'obtenir la caractéristique additionnelle suivante : une obturation sélective de la connection 92.In Figure 2 further appears a flange 1 16 linked to the crankshaft. This element, which is not necessarily present in the pump housing 1 15, however, makes it possible to obtain the following additional characteristic: a selective closure of the connection 92.
En effet le flasque 1 16 est découpé en périphérie de telle façon que seul un secteur angulaire donné obture l'orifice 92a de la connection 92, donc pendant une certaine plage angulaire donnée à d'un cycle moteur.Indeed, the flange 1 16 is cut at the periphery so that only a given angular sector closes the orifice 92a of the connection 92, therefore during a certain angular range given to a motor cycle.
Comme on le voit sur la figure 4, la pression Pβ dans le conduit 92 et la chambre 95b est stockée à une valeur donnée prise avant la chute de pression dans le carter-pompe, c'est-à- dire prise par exemple au moment de l'ouverture des transferts OT. Le flasque 116 permet ici de fermer l'orifice 92a jusqu'au moment souhaité pour déclencher l'ouverture de la soupape c'est-à-dire par exemple jusqu'au PMB selon la figure 4. L'obturation sélective du conduit 92 permet donc de stocker la pression carter Pβ pendant une durée déterminée par la valeur du secteur angulaire du flasque 1 16.As can be seen in FIG. 4, the pressure Pβ in the conduit 92 and the chamber 95b is stored at a given value taken before the pressure drop in the pump housing, that is to say taken for example at the time opening of OT transfers. The flange 116 here makes it possible to close the orifice 92a until the desired moment to trigger the opening of the valve, that is to say for example up to the PMB according to FIG. 4. Selective sealing of the conduit 92 allows therefore store the casing pressure Pβ for a period of time determined by the value of the angular sector of the flange 1 16.
Le retard de l'ouverture de la soupape est ici plus grand que dans le cas précédent puisque l'ouverture débute aux environs de 180° vilebrequin, alors que dans le cas précédentThe delay in opening the valve is greater here than in the previous case since the opening begins around 180 ° crankshaft, while in the previous case
(sans flasque) cette ouverture se situait autour de 165 vilebrequin ; rappelons que sans l'invention l'ouverture de la soupape s'effectue quand la pression dans le cylindre devient inférieure à la pression dans le conduit 87, soit pour le cas de figure envisagé, autour de 130° vilebrequin.(without flange) this opening was around 165 crankshaft; it should be recalled that without the invention the valve is opened when the pressure in the cylinder becomes lower than the pressure in the conduit 87, that is to say in the case envisaged, around 130 ° crankshaft.
Par ailleurs la flasque 1 16 selon l'invention permet de mieux contrôler l'ouverture de la soupape 86 puisque comme il apparaît notamment sur la figure 4 l'ouverture du conduit 92 étant franche, la chute de pression l'est tout autant de sorte que l'ouverture est aussi mieux contrôlée puisqu'elle ne dépend plus de la diminution de la pression dans le carter-pompe, diminution qui n'est pas toujours aussi rapide suivant les conditions de charge et régime du moteur, Selon ce mode de réalisation de l'invention, l'ouverture de la soupape dépend simplement de l'ouverture du conduit 92 par le flasque 1 16. Une autre amélioration de la présente invention peut consister à mettre en communication, de façon intermittente, la chambre 95a avec le carter-pompe 1 15.Furthermore, the flange 1 16 according to the invention allows better control of the opening of the valve 86 since, as it appears in particular in FIG. 4, the opening of the conduit 92 being frank, the pressure drop is just as much so that the opening is also better controlled since it no longer depends on the decrease in the pressure in the pump housing, a decrease which is not always as rapid depending on the load conditions and engine speed, According to this embodiment of the invention, the opening of the valve simply depends on the opening of the conduit 92 by the flange 1 16. Another improvement of the present invention can consist in communicating, intermittently, the chamber 95a with the pump housing 1 15.
Comme il va être expliqué plus en détail ci-après, en relation avec les figures 5 et 6, un tel mode de réalisation de l'invention permet notamment d'obtenir une ouverture plus rapide par une amplification du mouvement de la soupape, ainsi qu'une amélioration au niveau de la fermeture de la soupape. En effet, dans les modes de réalisation précédents, une certaine inertie de la soupape automatique a parfois pu être constatée, ce qui ralentit son ouverture.As will be explained in more detail below, in relation to FIGS. 5 and 6, such an embodiment of the invention makes it possible in particular to obtain faster opening by amplifying the movement of the valve, as well as '' an improvement in the closing of the valve. In fact, in the previous embodiments, a certain inertia of the automatic valve has sometimes been observed, which slows down its opening.
Ainsi, la figure 5 montre un mode de réalisation semblable aux précédents mais selon lequel le moteur comprend en outre une connection 91 entre la chambre 95a et le carter-pompe 1 15. Préférentiellement, la connection 91 débouche par une lumière 91a située dans la partie inférieure du cylindre, juste au- dessus du carter-pompe. Ainsi la connection 91 est mise en communication avec le carter-pompe quand le piston 1 12 passe au dessus de ladite lumière 9 1 a, c'est-à-dire de façon intermittente.Thus, FIG. 5 shows an embodiment similar to the previous ones but according to which the motor further comprises a connection 91 between the chamber 95a and the pump housing 1 15. Preferably, the connection 91 opens out through a light 91a located in the part lower of the cylinder, just above the pump housing. Thus the connection 91 is put in communication with the pump casing when the piston 1 12 passes above said light 9 1 a, that is to say intermittently.
Ainsi la connection 91 qui est donc contrôlée par la jupe de piston peut être fermée depuis l'ouverture des lumières de transfert 122 jusqu'à la fermeture de ces mêmes lumières c'est- à-dire de façon symétrique par rapport au point mort bas. Sans sortir du cadre de l'invention un autre phasage peut être obtenu, par exemple une ouverture et une fermeture non symétriques par rapport au point mort bas, grâce à un flasque lié au vilebrequin. Ce flasque peut ou non être le même que celui qui contrôle la connection 92. La figure 6 illustre le fonctionnement de ce mode de réalisation de l'invention .Thus the connection 91 which is therefore controlled by the piston skirt can be closed from the opening of the transfer lights 122 until the closing of these same lights, that is to say symmetrically with respect to the bottom dead center . Without departing from the scope of the invention, another phasing can be obtained, for example an opening and a closing which are not symmetrical with respect to the bottom dead center, thanks to a flange linked to the crankshaft. This flange may or may not be the same as that which controls the connection 92. FIG. 6 illustrates the operation of this embodiment of the invention.
La pression PA dans la chambre 95a, la pression Pβ dans la chambre 95b restent toutes deux égales à la pression dans le carter-pompe jusqu'à l'ouverture des transferts OT. La soupape 86 est alors maintenue sur son siège par la différence entre la pression PI dans le cylindre 1 13 et la pression Ps dans la capacité 87, aidé éventuellement d'un ressort de rappel .The pressure PA in the chamber 95a, the pressure Pβ in the chamber 95b both remain equal to the pressure in the pump casing until the transfers OT open. The valve 86 is then held in its seat by the difference between the pressure PI in cylinder 1 13 and pressure Ps in capacity 87, possibly assisted by a return spring.
Puis la lumière 91a est fermée par le piston.Then the light 91a is closed by the piston.
La lumière 92a peut éventuellement être fermée simultanément par le flasque 1 16 comme montré sur la figure 6, mais ceci n'est pas obligatoire.The light 92a can optionally be closed simultaneously by the flange 116 as shown in Figure 6, but this is not mandatory.
Le début de la commande de l'ouverture de la soupape se situe dès que la pression Pβ devient inférieure à la pression Ps dans la capacité. La chute de pression Pβ peut se produire soit naturellement c'est-à-dire sans le flasque 1 1 6, soit à l'ouverture de la lumière 92a par le flasque 1 16.The start of the valve opening control is located as soon as the pressure Pβ becomes lower than the pressure Ps in the capacity. The pressure drop Pβ can occur either naturally, that is to say without the flange 1 16, or at the opening of the light 92a by the flange 1 16.
A ce moment, la pression PA qui devient supérieure à la pression Pβ permet d'amplifier la force nécessaire à l'ouverture de la soupape moyennant un rapport adéquate entre la surface de la membrane 89 et celle de la soupape 86. L'ouverture de la soupape 86 est donc plus rapide et son amplitude peut aussi être augmentée grâce à cet effet.At this time, the pressure PA which becomes higher than the pressure Pβ makes it possible to amplify the force necessary for the opening of the valve by means of an adequate ratio between the surface of the membrane 89 and that of the valve 86. The opening of the valve 86 is therefore faster and its amplitude can also be increased thanks to this effect.
Par ailleurs, lorsque la lumière 91 a se trouve découverte par le piston (au voisinage de la fermeture des transferts FT selon la figure 6), alors la pression PA dans la chambre 91 a chute brutalement ce qui amorce la fermeture de la soupape 86, vus les différences de pression P] , PA , Pβ . PA et Pβ suivent dès lors les variations de la pression dans le carter-pompe, pression nettement inférieure à la pression Pi dans le cylindre. Comme il a déjà été dit, un ressort de rappel taré 93 peut équiper la tige de la soupape. Ce ressort sera choisi plus raide dans la dernière configuration car la force nécessaire à l'ouverture de la soupape est alors plus élevée que dans les cas précédents . La forte raideur du ressort 93 aidera à la fermeture, qui s'en trouve facilitée.Furthermore, when the light 91 a is found by the piston (in the vicinity of the closing of the transfers FT according to FIG. 6), then the pressure PA in the chamber 91 drops suddenly which initiates the closing of the valve 86, seen the pressure differences P], PA, Pβ. PA and Pβ therefore follow the variations in the pressure in the pump housing, a pressure much lower than the pressure Pi in the cylinder. As already mentioned, a calibrated return spring 93 can be fitted to the valve stem. This spring will be chosen stiffer in the last configuration because the force required to open the valve is then higher than in the previous cases. The strong stiffness of the spring 93 will help the closure, which is thereby facilitated.
Il est possible, selon ce mode de réalisation de l'invention, de limiter la course de la soupape par des moyens appropriés tels que des butées (non représentées). It is possible, according to this embodiment of the invention, to limit the stroke of the valve by suitable means such as stops (not shown).

Claims

REVENDICATIONS
1) Moteur à deux temps comportant au moins1) Two-stroke engine with at least
- un cylindre ( 1 1 1 ) dans lequel se déplace un piston ( 112) et dont l'une des extrémités communique avec un carter-pompe- a cylinder (1 1 1) in which a piston (112) moves and one end of which communicates with a pump housing
( 1 15) traversé par le vilebrequin ( 1 14) du moteur,(1 15) crossed by the crankshaft (1 14) of the engine,
- une capacité sous pression (87) débouchant à une extrémité dans la chambre de combustion ( 1 13 ) du cylindre ( 1 1 1 ), au moins une soupape (86) assurant l'obturation intermittente entre la chambre (113) et la capacité (87),- a pressurized capacity (87) opening at one end into the combustion chamber (1 13) of the cylinder (1 1 1), at least one valve (86) ensuring intermittent obturation between the chamber (113) and the capacity (87),
- un moyen (88) destiné à carburer le gaz passant dans ladite capacité (87),a means (88) intended to carburize the gas passing through said capacity (87),
- un moyen de commande de l'ouverture de ladite soupape (86) comprenant une membrane sou ple (89 ) séparant deux chambres (95a, 95b) et reliée à la tige de la soupape, caractérisé en ce qu'il comprend en outre- A means for controlling the opening of said valve (86) comprising a flexible membrane (89) separating two chambers (95a, 95b) and connected to the valve stem, characterized in that it further comprises
- un moyen de liaison (92) entre l'une (95b) desdites chambres et le carter-pompe ( 1 15) dudit cylindre, permettant notamment de déclencher l'ouverture de la soupape (86) au plus tôt quand la pression Pβ dans la chambre (95b) devient inférieure à la pression PS dans ladite capacité (87).- A connecting means (92) between one (95b) of said chambers and the pump housing (1 15) of said cylinder, allowing in particular to trigger the opening of the valve (86) at the earliest when the pressure Pβ in the chamber (95b) becomes lower than the pressure PS in said capacity (87).
2) Moteur selon la revendication 1 , caractérisé en ce que ladite capacité (87) débouche par son autre extrémité dans une ouverture (127) du carter-pompe ( 1 15) et en ce qu'il comprend en outre un moyen de contrôle de ladite ouverture ( 127) de ladite capacité (87) au niveau du carter-pompe (1 15) du cylindre2) Motor according to claim 1, characterized in that said capacity (87) opens at its other end into an opening (127) of the pump housing (1 15) and in that it further comprises a means of controlling said opening (127) of said capacity (87) at the pump housing (1 15) of the cylinder
( 1 1 1 ),(1 1 1),
3) Moteur selon l'une quelconque des revendications 1 ou 2, caractérisé en ce qu'il comprend en outre, un moyen destiné à obturer de façon intermittente ledit moyen de liaison (92) afin de retarder la chute de pression dans le moyen de liaison (92) c'est- à-dire l'ouverture de la soupape (86).3) Motor according to any one of claims 1 or 2, characterized in that it further comprises, means intended to intermittently seal said connecting means (92) in order to delay the pressure drop in the means of link (92), that is to say the opening of the valve (86).
4) Moteur selon la revendication 2, caractérisé en ce que ledit moyen d'obturation intermittente comprend un flasque (1 16) placé dans le carter-pompe ( 1 1 5 ), lié en rotation au vilebrequin du moteur et comprenant au moins un évidement périphérique.4) Motor according to claim 2, characterized in that said intermittent shutter means comprises a flange (1 16) placed in the pump housing (1 1 5), linked in rotation to the engine crankshaft and comprising at least one peripheral recess.
5) Moteur selon l'une quelconque des revendications précédentes, caractérisé en ce qu'i l comprend en outre des moyens de contrôle liés à la fermeture de la soupape.5) Engine according to any one of the preceding claims, characterized in that it further comprises control means related to the closing of the valve.
6) Moteur selon la revendication 4, caractérisé en ce que lesdits moyens comprennent un moyen de connection (91 ) entre l'autre desdites chambres (95a) et ledit carter-pompe ( 1 15), ledit moyen étant agencé de telle sorte qu'il est obturé de façon intermittente coté carter-pompe ( 1 15), ledit moyen permettant alternativement d'amplifier l'ouverture de la soupape et d'aider à sa fermeture.6) Motor according to claim 4, characterized in that said means comprise a connection means (91) between the other of said chambers (95a) and said pump housing (1 15), said means being arranged so that it is intermittently closed on the pump housing side (1 15), said means alternately making it possible to amplify the opening of the valve and to assist in its closing.
7) Moteur selon l'une quelconque des revendications précédentes, caractérisé en ce qu'il comprend en outre un élément élastique de rappel (93) de la soupape (86) sur son siège7) Motor according to any one of the preceding claims, characterized in that it further comprises an elastic return element (93) of the valve (86) on its seat
(85), qui coopère avec ladite membrane souple (89).(85), which cooperates with said flexible membrane (89).
8) Moteur selon la revendication 5, caractérisé en ce que ledit moyen de connection (91 ) débouche par une ouverture (91 a) dans la partie inférieure du cylindre de façon à être alternativement couverte et découverte par le piston ( 1 12).8) Engine according to claim 5, characterized in that said connection means (91) opens through an opening (91 a) in the lower part of the cylinder so as to be alternately covered and uncovered by the piston (1 12).
9) Moteur selon la revendication 5 , caractérisé en ce que l'obturation intermittente du moyen de connection (91 ) est réalisée par un flasque spécifique lié au vilebrequin.9) Engine according to claim 5, characterized in that the intermittent sealing of the connection means (91) is achieved by a specific flange linked to the crankshaft.
10) Moteur selon l'une quelconque des revendications précédentes, caractérisé en ce qu'il comporte en outre une butée limitant l'amplitude d'ouverture de la soupape (86).10) Engine according to any one of the preceding claims, characterized in that it further comprises a stop limiting the opening amplitude of the valve (86).
1 1 ) Procédé de contrôle de l'ouverture d'une soupape d'injection de mélange carburé dans un moteur à combustion interne selon l'une quelconque des revendications précédentes, caractérisé en ce qu'il consiste à commander ladite ouverture au plus tôt lorsque la pression Pβ dans la liaison devient inférieure à la pression Ps dans la capacité (87). 1 1) A method of controlling the opening of a fuel mixture injection valve in an internal combustion engine according to any one of the preceding claims, characterized in that it consists in controlling said opening as soon as possible when the pressure Pβ in the connection becomes lower than the pressure Ps in the capacity (87).
EP95924382A 1994-09-09 1995-06-28 Two-stroke engine comprising an enhanced injection device and associated injection method Expired - Lifetime EP0786045B1 (en)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
FR9410782A FR2724415B1 (en) 1994-09-09 1994-09-09 TWO-STROKE ENGINE WITH IMPROVED INJECTION DEVICE AND INJECTION METHOD THEREOF
FR9410782 1994-09-09
PCT/FR1995/000866 WO1996007817A1 (en) 1994-09-09 1995-06-28 Two-stroke engine comprising an enhanced injection device and associated injection method

Publications (2)

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EP0786045A1 true EP0786045A1 (en) 1997-07-30
EP0786045B1 EP0786045B1 (en) 2000-03-08

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US (1) US5809949A (en)
EP (1) EP0786045B1 (en)
JP (1) JPH10505147A (en)
KR (1) KR970705706A (en)
CN (1) CN1073199C (en)
AT (1) ATE190381T1 (en)
AU (1) AU704865B2 (en)
DE (1) DE69515499T2 (en)
FR (1) FR2724415B1 (en)
TW (1) TW347437B (en)
WO (1) WO1996007817A1 (en)

Families Citing this family (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2724415B1 (en) * 1994-09-09 1996-12-20 Inst Francais Du Petrole TWO-STROKE ENGINE WITH IMPROVED INJECTION DEVICE AND INJECTION METHOD THEREOF
FR2744764B1 (en) * 1996-02-12 1998-04-17 Inst Francais Du Petrole TWO STROKE MOTOR WITH A MEANS OF CONTROL OF THE MOVEMENT OF THE VALVE
US6079379A (en) * 1998-04-23 2000-06-27 Design & Manufacturing Solutions, Inc. Pneumatically controlled compressed air assisted fuel injection system
US6591792B2 (en) * 1999-11-12 2003-07-15 Maruyama Mfg. Co., Inc. Two-cycle engine
US7270110B2 (en) * 2000-04-24 2007-09-18 Frank Keoppel Four stroke internal combustion engine with inlet air compression chamber
US20040007192A1 (en) * 2000-04-24 2004-01-15 Frank Keoppel Four stroke internal combustion engine with isolated crankcase
US6536384B1 (en) 2000-04-24 2003-03-25 Frank Keoppel Two-stroke internal combustion engine with isolated crankcase
KR100545110B1 (en) * 2000-12-02 2006-01-24 김경환 Cross flow engine
US6889636B2 (en) * 2003-09-03 2005-05-10 David S. W. Yang Two-cycle engine
KR20080027926A (en) * 2005-07-15 2008-03-28 한스-알민 올만 Two-stroke internal combustion engine with enhanced scavenging
WO2009044412A2 (en) * 2007-10-05 2009-04-09 Indian Institute Of Technology An air-fuel injection system for two stroke internal combustion engines
CN103104368A (en) * 2012-01-18 2013-05-15 摩尔动力(北京)技术股份有限公司 Leakproof thermomotor

Family Cites Families (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS55137313A (en) * 1979-04-14 1980-10-27 Yamaha Motor Co Ltd Two-stroke cycle engine
JPS5791317A (en) * 1980-11-26 1982-06-07 Tokyo Gas Co Ltd Two-cycle internal combustion engine
US4619228A (en) * 1984-10-11 1986-10-28 Textron Inc. Automatic compression release for two-cycle engine
US4865002A (en) * 1988-02-24 1989-09-12 Outboard Marine Corporation Fuel supply system for internal combustion engine
FR2641336B1 (en) * 1988-12-30 1994-05-20 Institut Francais Petrole DEVICE AND METHOD FOR INTRODUCING A FUEL MIXTURE INTO A CHAMBER OF A TWO-STROKE ENGINE
FR2656656B1 (en) * 1989-12-29 1994-05-20 Institut Francais Petrole TWO - STROKE ENGINE WITH PNEUMATIC INJECTION CONTROLLED.
DE4000864A1 (en) * 1990-01-13 1991-07-18 Fichtel & Sachs Ag Pneumatically controlled decompression unit - is for IC engine and uses membrane to create two separate pressure zones
JP2656656B2 (en) * 1990-09-17 1997-09-24 株式会社日立製作所 Laser processing device, alignment device used for the same, and processing head
JPH07310554A (en) * 1993-03-31 1995-11-28 Mitsubishi Heavy Ind Ltd Crank case compression type two-cycle engine
FR2724415B1 (en) * 1994-09-09 1996-12-20 Inst Francais Du Petrole TWO-STROKE ENGINE WITH IMPROVED INJECTION DEVICE AND INJECTION METHOD THEREOF

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
See references of WO9607817A1 *

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Publication number Publication date
ATE190381T1 (en) 2000-03-15
WO1996007817A1 (en) 1996-03-14
KR970705706A (en) 1997-10-09
DE69515499D1 (en) 2000-04-13
AU1511397A (en) 1998-01-29
CN1157646A (en) 1997-08-20
FR2724415A1 (en) 1996-03-15
CN1073199C (en) 2001-10-17
DE69515499T2 (en) 2000-11-23
TW347437B (en) 1998-12-11
EP0786045B1 (en) 2000-03-08
US5809949A (en) 1998-09-22
JPH10505147A (en) 1998-05-19
FR2724415B1 (en) 1996-12-20
AU704865B2 (en) 1999-05-06

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