EP0346188A1 - Device and method for the introduction of a pressurized air-fuel mixture into the cylinder of an engine - Google Patents

Abstract

The present invention relates to a method and a device for the introduction of a pressurised air-fuel mixture into a first cylinder of an internal-combustion engine, this engine comprising at least one other cylinder having a pump housing. The device according to the invention is characterised in that it has a connecting pipe (15) between the housing (14) and the first cylinder (1), in that there is an non-zero angular offset between the cycle of each of the cylinders, and in that at least one of the ports for the transfer of gas between the said other cylinder and its pump housing is positioned so that a return flow occurs during part of the cycle, <IMAGE>

Description

The present invention relates to a method and devices improving the introduction under pressure of a fuel mixture at the end of air sweeping in a 2-stroke engine cylinder. According to the present invention, the pressure source used is supplied by the pressure prevailing in the cylinder crankcase which is 120 ^o behind the crankshaft (case of an engine 3, 6, ..., 3n cylinders) or by the crankcase of the cylinder 90 ^o behind the crankshaft (4, 8, ..., 4n cylinders engine) with respect to the cylinder considered where the fuel mixture takes place, as well as by the return flow (generally designated by the Anglo-Saxon term of "back-flow") which is caused in a transfer duct of the late cylinder, this transfer duct connecting this cylinder to its pump casing (back-flow cylinder-casing ).

The introduction of a fuel mixture under pressure occurs on the arrival of gases from this pressure source in the cylinder considered during its end of sweeping phase. The arrival of gas from the pump housing into a fuel metering device prepares a fuel mixture which can be introduced into the cylinder through an orifice.

According to the present invention, the introduction and optionally the preparation of the fuel mixture into the cylinder in question is prolonged and improved by the use of return gases in the transfer duct coming from the lagging cylinder and which are at a high pressure level. .

The use of these gases in return can be made directly. Under these conditions there will be a direct connection between the transfer duct and the fuel metering device or directly by performing a transit through the pump housing of the late cylinder.

The opening for introducing the fuel mixture into the cylinder in question may preferably be opened only during the arrival of the gases coming from the pump housing of the late cylinder and of the late cylinder itself. This hole can be in the cylinder head.

In this case, the device may include a valve controlled to open during the arrival of the gases from this pressure source, or an automatic valve (non-return valve type), the opening of which is controlled by the difference between the pressure from the pressure source and the pressure of the cylinder considered.

The hole can also be in the cylinder. Its opening can then be controlled by the movement of the piston (in the case of a light) combined with a non-return device of the valve type (or with a rotary plug).

For example, one embodiment of this type may consist in connecting the cylinder housing delayed by an angle of 120 or 90 ^o of the crankshaft relative to the cylinder in question, via a connection conduit opening on the side opposite to the exhaust in the cylinder in question (conduit generally called rear transfer conduit).

Insofar as the fuel metering location (upstream of the injection orifice opening into the cylinder) is not under a pressure higher than ambient pressure for all the time outside the period of introduction of fuel mixture, this metering can be carried out using '' low pressure injectors, but also using simpler devices, such as, for example, a carburetor of the type used for the intake of a two-stroke engine.

In general, the present invention relates to a device for introducing under pressure the fuel mixture into a first cylinder of an internal combustion engine, this engine comprising at least one other cylinder having a pump housing. The device according to the invention is characterized in that it comprises a connecting pipe between said pump housing and the first cylinder, in that there is a non-zero angular offset between the cycle of each of said cylinders and in that 'at least one of the gas transfer lights between said other cylinder and its pump housing is positioned so that there is a return flow during part of the cycle.

This angular offset can be 120 ^o and the cycle of the first cylinder can precede the cycle of the other cylinder by 120 ^o .

Likewise, this angular offset may be 90 ^o and the cycle of the first cylinder may precede by 90 ^o the cycle of the other cylinder.

The device according to the invention applies in particular to engines comprising a number of cylinders multiple of 3 or 4.

The pipeline may open into the first cylinder in the vicinity of the cylinder head of the engine.

Likewise, the pipeline may open into the first cylinder on the side wall of this cylinder, substantially at the bottom of this cylinder.

The device according to the invention may include a shutter member placed between the pipe and the first cylinder, substantially in the vicinity of the latter.

The shutter member may be a valve controlled by a cam, or a rotating plug.

Likewise, the shutter member may be automatic and be adapted to act like a valve.

The pipeline may include a fuel introduction and metering device.

This fuel introduction device may be a low pressure injector, just as it may include a venturi nozzle associated with said low pressure injector.

The fuel introduction device may be a carburetor.

The control of this carburetor can be coupled with a control that controls the amount of gas introduced into the pump housing of the first cylinder.

The device according to the invention may comprise between the carburetor and the pipe a non-return element such as a valve.

It will not depart from the scope of the present invention if the fuel introduction and metering member comprises a diaphragm pump actuated by the pressure pulses of a pump housing.

The outlet duct of this diaphragm pump which connects the latter to the pipeline, may include a system for adjusting its passage section. This system may include a needle and control means taking into account the average pressure of a casing.

Said connecting pipe may advantageously have a common part with the transfer duct which connects the pump housing with said lumen.

An aerodynamic profiled part may be placed at the interconnection of the connecting pipe, said transfer duct and said transfer lumen.

A non-return valve may be placed on said transfer duct, said valve not allowing flow back to the pump housing.

The piston of said other cylinder may be bevelled or scalloped over a part of its surface to allow a return flow through at least one transfer lumen in order to facilitate the return flow.

The lumen where the back flow occurs may be positioned so that said flow occurs only after at least one exhaust lumen of said other cylinder has been discovered by said piston of said other cylinder.

The present invention also relates to a method of introducing under pressure the fuel mixture into a first cylinder of an internal combustion engine, this engine comprising at least one other cylinder having a pump housing, this pump housing communicating with said other cylinder. by at least one transfer light. This method is characterized in that the pressure of the gases contained in said pump housing is used as a source of pressure to inject the fuel mixture into the other cylinder and in that a backward flow is caused through said transfer light for temporarily increasing the pressure in said casing or in a transfer.

When the present invention is applied to a multi-cylinder engine in which each cylinder comprises a pump housing, each of the cylinders may be connected, directly or not, to a pump housing of another cylinder angularly delayed with respect to the cylinder considered.

Thus, in the case of a three-cylinder engine each having a pump-housing, each cylinder may be in connection with the pump-housing of the cylinder which is 120 ^o behind the crankshaft relative to the cylinder in question.

• - la figure 1 illustre les courbes de pression régnant dans le carter du cylindre en retard et dans le cylindre en retard,
• - la figure 2 illustre les courbes de pression dans le conduit de transfert du cylindre en retard et dans le cylindre considéré,
• - la figure 3 est relative au cas d'une introduction retardée de 120^o Vilebrequin du mélange carburé dans la chambre de combustion du cylindre considéré, via une soupape commandée,
• - la figure 4 montre le cas d'une introduction retardée de 120^o vilebrequin du mélange carburé dans la chambre de combustion du cylindre considéré, via une soupape automatique,
• - la figure 5 illustre le cas d'une introduction retardée de 120^o vilebrequin du mélange carburé par une lumière arrière du cylindre considéré, via un clapet anti-retour,
• - la figure 6 est relative au cas d'une introduction retardée de 120^o vilebrequin de mélange carburé par une lumière arrière du cylindre considéré, via un boisseau rotatif,
• - la figure 7 montre le cas d'une introduction retardée de 90^o vilebrequin de mélange carburé dans une lumière arrière du cylindre considéré,
• - la figure 8 illustre un dispositif de dosage et d'introduction du carburant par la pression régnant dans le carter,
• - la figure 9 est semblable à la figure 8, mais avec le perfectionnement du dispositif de dosage en fonction de la charge du moteur,
• - la figure 10 montre le cas d'une introduction de mélange carburé préalablement admis via un carburateur classique,
• - la figure 11 représente la mise en place d'un déflecteur profilé, ou pièce aérodynamique,
• - la figure 12 illustre un mode de réalisation particulier dans lequel le conduit de transfert comporte un clapet, et
• - la figure 13 montre le cas où le piston comporte une échancrure au déflecteur permettant de libérer plus tôt une lumière de transfert relativement à d'autres lumières de transfert de ce même cylindre.

The invention will be clearly understood on reading the following description of exemplary embodiments, illustrated by the appended figures, among which:

• FIG. 1 illustrates the pressure curves prevailing in the case of the late cylinder and in the late cylinder,
• FIG. 2 illustrates the pressure curves in the transfer duct of the late cylinder and in the considered cylinder,
• FIG. 3 relates to the case of a delayed introduction of 120 ^o Crankshaft of the fuel mixture into the combustion chamber of the cylinder in question, via a controlled valve,
• FIG. 4 shows the case of a delayed introduction of 120 ^o crankshaft of the fuel mixture into the combustion chamber of the cylinder in question, via an automatic valve,
• FIG. 5 illustrates the case of a delayed introduction of 120 ^o crankshaft of the fuel mixture by a rear light of the cylinder in question, via a non-return valve,
• FIG. 6 relates to the case of a delayed introduction of 120 ^o crankshaft of fuel mixture by a rear light of the cylinder in question, via a rotary plug,
• FIG. 7 shows the case of a delayed introduction of 90 ^o crankshaft of fuel mixture into a rear light of the cylinder considered,
• FIG. 8 illustrates a device for metering and introducing fuel by the pressure prevailing in the crankcase,
• FIG. 9 is similar to FIG. 8, but with the improvement of the metering device as a function of the engine load,
• FIG. 10 shows the case of an introduction of a fuel mixture previously admitted via a conventional carburetor,
• FIG. 11 represents the installation of a profiled deflector, or aerodynamic part,
• FIG. 12 illustrates a particular embodiment in which the transfer duct comprises a valve, and
• - Figure 13 shows the case where the piston has a notch in the deflector to release earlier a transfer light relative to other transfer lights of the same cylinder.

Figure 1 shows in solid lines with the reference P1, the pressure variation curve as a function of the angle of rotation of the crankshaft in a cylinder of a two-stroke engine, near the bottom dead center corresponding to a crankshaft angle 180 ^o .

The curve of variation of the pressure of the casing equipping this cylinder is indicated in dotted lines, and bears the reference P2 According to the present invention at least one of the transfer ports which connects this cylinder to the pump housing of this cylinder via a transfer conduit is positioned high enough to open before the pressure of the housing -pump is greater than or equal to the pressure in the cylinder. Thus there is a flow in the opposite direction to that generally accepted in the transfer conduits. It is this reverse flow, or return, which is the source of the pressure peak 101 in FIG. 1.

This pressure peak can therefore make it possible to extend the duration of the introduction of fuel mixture during the whole part of the operating cycle of the cylinder considered where the pressure difference is sufficient to allow the introduction of fuel into the cylinder. By the choice and the design of the mode of introduction adopted: controlled valve, automatic valve, light more valve, or light more rotary valve, it is possible to control more or less the most favorable moment for the introduction of this mixture carbide.

Figure 2 shows the pressure curve P3 in the cylinder considered as a function of the degree of rotation of the crankshaft, with a pressure source P4 coming from a transfer duct of a cylinder lagging 120 ^o crankshaft relative to the cylinder considered . This corresponds in particular to the case of an engine comprising three cylinders.

The pressure curves P2 and P4 are close to each other since one P4 is taken in a transfer duct and the other P2 in the pump housing connected to this transfer duct. In FIG. 2, the pressure peak 102 which corresponds to the pressure peak 101, allows the fuel injection pressure to accompany for a sufficiently long time the pressure curve P3 in the cylinder. It is thus possible to improve the injection.

Thus, the pressure peak 102 can be chosen to occur during the end of the injection period, at the moment when the cylinder pressure increases (start of compression) and therefore a higher injection pressure is necessary to continue l introduction of the injected mixture in the direction of injection member towards cylinder and avoid reversal of direction at the end of injection, such inversion may be responsible for a loss of compression and cylinder filling.

In the case of a multi-cylinder engine, the connection conduit between the two external "cylinders" being longer, this disadvantage can be overcome, if necessary, by placing, in the cylinder, the transfer light supplying the connection conduit between the two external cylinders higher than the other transfer lights which supply the connection conduits of the other cylinders.

Figures 3, 4, 5, 6, 7 show in solid lines the cylinder considered 1 with its piston 2 at the end of scanning, its exhaust 3, its exhaust light 4 which is about to be closed, its lights lateral transfer 5, and rear transfer 6, its casing 7 with an air intake only, for example by valves 8, its spark plug 9, the rod-crank system 10.

In dashed lines is shown the cylinder 11 having a piston 2R whose movement is angularly delayed by 120 ^o by means of the rod-crank system 13, relative to the piston 2 of the cylinder considered 1. The piston 2R is in the expansion phase in the cylinder 11 and at the same time of compression in the pump housing 14.

The pump casing 14 whose movement of the piston 2R is angularly delayed by 120 ^o supplies the source of pressure through the conduit 15.

The transfer light 6R of the cylinder 11 is positioned high enough for there to be a return flow.

It has been assumed in FIG. 3 that the cylinder 1 in turn serves as a source of pressure for another cylinder. Thus, the cylinder 1 is identical in its configuration to the cylinder 11 with regard in particular to the positioning of the lights.

The flow back into the casing 7 is allowed by the fact that the rear transfer light 6 is raised from what should be its normal height so that there is no reverse flow. This normal height is represented by the position of the lateral transfer lumen 5.

As shown in Figure 3, there is a DH1 offset between the top of the rear lights 6 and 5. However, in the case shown in Figure 3, the rear transfer light 6 opens later than the light exhaust 4. The distance between the top of the light 6 and the exhaust light 4 is the reference DH2.

In the case of FIGS. 3 and 4, the duct 15 is connected to the combustion chamber 16 of the cylinder considered 1.

The introduction of the pressurized air from the pump housing 14 into the chamber 16 takes place through an orifice 18, the opening of which is controlled by a valve 19. Upstream of the valve is a device for introducing and low-pressure fuel metering 20.

This device can be a low-pressure injector that is commercially available, or a fuel pump actuated by the successive pressures and depressions of a pump housing. A diagram of this latter device will be specified in FIG. 8. The introduction of the liquid fuel can take place in the duct 15, both during the whole time when the valve 19 is closed and during that when it is open.

This fuel metering and introduction device 20 can be associated with a venturi nozzle 21 placed in the duct 15, just upstream from the valve 19 and the orifice 18, in accordance with patent EP-189,714, in order to improve the spraying of fuel with air from the pressure source (pump housing 14).

Just downstream of the orifice 18, it is also advantageously possible to place a deflector 22, or device for orienting the jet of mixture introduced into the cylinder. This device forming part of the cylinder head or attached to the cylinder head is for example of the type described in patent EP-189,715.

In the particular case of FIG. 3, the valve 19 is controlled mechanically, for example by a cam 23 driven in rotation at the speed of the motor. This cam controls the movement of the valve 19 by means of a pusher 24. The valve 19 is returned by a spring 25. It will not depart from the scope of the present invention if this valve is controlled by another means, such as electromagnetic means.

In the particular case of FIG. 4 which illustrates another variant, the valve 19 is not controlled. It is simply fitted with a return spring 25. It is left free to move as a function of the upstream and downstream pressure differences. It then acts like a flap or automatic valve.

In the case of the two figures 3 and 4, when the pressure in the casing 14 is higher than the pressure in the cylinder 1 considered, the introduction of fuel mixture can occur in the cylinder 1, either at the selected controlled time (FIG. 3), or automatically during this period of pressure difference, between casing 14 and cylinder 1 (Fig. 4). In both cases, the movement of the piston 2 is such that it closes the exhaust port 4 before the fuel can escape from the cylinder 1 in the exhaust 3, through this same port 4.

In the case of FIGS. 5 and 6, the duct 15 coming from the source of compressed air 14 is connected to an injection light opening into the walls of the cylinder and preferably to a rear injection light 6, so called because it is substantially opposite to the exhaust light. Near the light 6 and downstream from it, a non-return valve 26 prevents the gases from the cylinder 1 from entering the casing 14 during the vacuum phase of the latter.

Upstream of the valve, there is the device 27 for metering and introducing low-pressure fuel. This fuel introduction can take place at any time during the cycle, even when the light 6 is closed by the piston 2.

This fuel metering and introduction device 27 can be a low-pressure injector that is commercially available, or a fuel pump actuated by the successive pressures and depressions of a pump housing (Fig. 8) , or a conventional carburetor actuated by the air flow passing through it. In the latter case, a second external air intake circuit should be provided, for example through this carburetor and through the duct 15. A schematic representation is made of it in FIG. 10.

The notch 12 makes it possible to direct the mixture injected into the cylinder 1 as well as to define the timing of the injection. This can also be obtained by making a bevel or a notch on the part of the piston which cooperates with the injection port.

Of course, the cylinder 1 of FIG. 5 may include a rear transfer light and a rear transfer duct (not represented).

In all cases, the spraying of the fuel mixture may be advantageously improved by a nozzle-venturi type device 28 placed just upstream of the valve 26 in accordance with patent FR-2,575,521.

In the case of FIG. 6, the valve 6 is replaced by a rotary plug 29 driven by the rotation of the motor and thus preferably controlling the opening of the light 6.

Figure 7 shows the case of Figure 6 where the pressure source is provided by the movement in the pump housing 14 of a piston 2R angularly delayed 90 ^o crankshaft relative to the movement of the piston 2 of the cylinder considered 1. It It is obvious that the cases of FIGS. 3, 4, 5 could also be described in the same way with this delay of 90 ^o crankshaft instead of 120 ^o .

FIG. 8 shows a schematic representation of a fuel metering device which can be used in place of the devices 20 or 27.

This device pumps the fuel from the tank 30 via the non-return valve 31 to the duct 34, through the non-return valve 33. The membrane 32 acts as a fuel pump. On the one hand it is in contact with the fuel it pumps. On the other side, its reciprocating movement which allows this pump role is actuated by the pressure pulses coming from a pump casing which can be either casing 7 or casing 14 and which is connected to this side of the membrane via conduit 35.

During the intake phase of the pump crankcase, the latter is under vacuum and therefore controls the diaphragm 32 so as to increase the volume 36 thereby sucking fuel through the valve 31 which opens. Then, during the compression phase of the crankcase, the movement of the diaphragm 32 reduces the volume 36 and therefore pumps the fuel into the duct 34 via the valve 33.

This device therefore acts as a pump and fuel metering. It is slaved to engine speed, since it provides one pump movement per revolution, and it is also slaved to load, since the amplitude of the pressure pulses in the crankcase is proportional to the load.

In the case where it is used alone, without additional finer metering means, the pipe 34 is then directly connected to the location in the pipe 15 where the fuel is introduced.

In the case where a finer adjustment of the fuel flow rate relative to the load is necessary, the opening of the duct 34 is adjusted as a function of the load by a needle 37 which can be actuated either directly or indirectly by a lever 38 connected to another membrane 39. The other side of the membrane 39 is again in communication with the pressure of a motor crankcase via a conduit 40.

The inertia of the assembly constituted by the needle 37, the lever 38 and the membrane 39 is chosen such that it does not allow movement of the membrane 39 according to the pulsations of instantaneous pressure of a casing. It must be studied in order to be controlled only by the average pressure of a crankcase, a pressure which is directly representative of the engine load. This results in a position of the metering needle directly representative of the engine load. At the point of the needle, the fuel thus dosed is guided by the pipe 41 to the place of introduction into the pipe 15.

Figure 10 shows another particularly simple embodiment of the metering device.

The pressure source of the casing 14 through the conduit 15 which serves for the introduction of fuel mixture into the cylinder 1, also serves during its vacuum phase for the suction of very rich fuel mixture via a conventional carburetor 42 and a device non-return valve 43. The carburetor is for example a carburetor of the conventional type for 2-stroke engine, with plug and needle correcting the nozzle nozzle with the load.

The assembly then forms a true second very rich mixture intake circuit, separated from the intake via the air valve 8 only.

The length of the conduit 15 may be studied so as not to allow the fuel mixture thus admitted into this conduit to reach the pump housing 14 before being pushed back into the cylinder 1 by the pressure of the pump housing 14 returned to the compression phase. .

Another very advantageous advantage lies in the fact that, in the case of a multi-cylinder engine whose set of cylinders operates according to the principle of the invention, with the suitable combinations of conduits 15, a single carburetor 42 can be used for all of the cylinders. Downstream of the carburetor, the different conduits 44 can be separated to end up at the different cylinders, in order to be able to supply with fuel mixture their respective conduits 15 through their respective valves 43.

The carburetor device of FIG. 10, a variant of the case of FIG. 5, can also be adapted to the case of FIGS. 3, 4 and 6.

In FIGS. 3, 5 and 10, the duct 15 connects the transfer duct 17R of the overdue cylinder 11 to the fuel supply orifice of the cylinder in question, the transfer duct 17R being that in which the flow occurs in return. Such an arrangement makes it possible to take better advantage of the pressure effects of the flow in return. However, it will not depart from the scope of the present invention if the conduit 15 is connected to the pump housing so that the effects of the return flow pass through the pump housing.

Figures 11 and 12 show the interconnection between the conduit 15, the rear transfer conduit 17R and the rear transfer lumen 6R.

A valve 45 (Fig. 12) may be installed in the transfer duct 17R in order to minimize the effects of the flow back from the cylinder 2R to the casing 14 while keeping the advantages of injection at the injection level. cited above. A system having the same purpose can be achieved by playing only on the aerodynamics of the conduits by the interposition of a profiled part 46 (FIG. 11).

This profiled part has an edge 47 which is flush with the cylinder 11 at the level of the rear transfer lumen 6R in which the return flow takes place.

This edge 47 divides the orifice 6R into two parts, an upper part and a lower part.

When the piston 2R descends and as long as it has not discovered the light 6R, the flow takes place from the pump housing 14 via the rear transfer duct 17R, supplies gases under pressure to the duct 15.

When the piston 2R discovers the orifice 6R, it discovers the upper part first while the pressure of the cylinder 2R is higher than that of the casing 14. As a result, there is a return flow which should be directed towards the conduit 15 and this is the role of the surface 48 of the profiled part 46.

When the piston continues its downward stroke, the return flow ceases and gives way to a flow in the direction pump casing 14 towards cylinder 11 and in this case, it is surface 49.

The orifice 51 serves to facilitate the passage of the gases coming from the conduit 17R.

In FIG. 13, the piston 2R is bevelled at 52 so as to make it possible to anticipate the opening of the light 6R so that a return flow occurs there.

Thus, it is possible to easily adapt the device according to the invention to an already existing motor, the height of the transfer lights of which had not been provided for return flows.

Without departing from the scope of the present invention, it is possible to adapt a system making it possible to vary the level of the transfer light serving as a pressure source and this as a function of one or more parameters (for example as a function of the speed, of the charge...).

Claims (25)

1. - Device for introducing the fuel mixture under pressure into a first cylinder of an internal combustion engine, this engine comprising at least one other cylinder having a pump casing, characterized in that it comprises a connecting pipe ( 15) between said pump housing (14) and the first cylinder (1), in that there is a non-zero angular offset between the cycles of said cylinders and in that at least one of the gas transfer ports between said another cylinder and its pump housing is positioned so that there is a return flow during part of the cycle. 2. - Device according to claim 1, characterized in that said angular offset is 120 ^o and in that the cycle of the first cylinder precedes by 120 ^o the cycle of the other cylinder. 3. - Device according to claim 1, characterized in that said angular offset is 90 ^o and in that the cycle of the first cylinder precedes by 90 ^o the cycle of the other cylinder. 4. - Device according to claim 2, characterized in that said engine comprises a number of cylinders multiple of 3. 5. - Device according to claim 4, characterized in that said engine comprises a number of cylinders multiple of 4. 6. - Device according to claim 1, characterized in that said pipe (15) opens into the first cylinder in the vicinity of the cylinder head of the engine. 7. - Device according to claim 1, characterized in that said pipe (15) opens into the first cylinder (1) on the wall side of this cylinder, substantially at the bottom of this cylinder. 8. - Device according to claim 1, characterized in that it comprises a shutter member (19, 26, 29) placed between said pipe (15) and said first cylinder (1), substantially in the vicinity of the latter. 9. - Device according to claim 8, characterized in that said shutter member is a valve (19) controlled by a cam (23) or electromagnetically. 10. - Device according to claim 8, characterized in that said shutter member is automatic and is adapted to act in the manner of a valve. 11. - Device according to claim 8, characterized in that said shutter member is a rotating plug (29). 12. - Device according to claim 1, characterized in that said pipe comprises a fuel introduction and metering member (20, 27, 42). 13. - Device according to claim 12, characterized in that said fuel introduction device is a low pressure injector. 14. - Device according to claim 13, characterized in that it comprises a venturi nozzle (21, 28) associated with said low pressure injector. 15. - Device according to claim 12, characterized in that said fuel introduction device is a carburetor (42). 16. - Device according to claim 15, characterized in that the control of said carburetor is coupled with a control which controls the amount of gas introduced into the pump housing of said first cylinder. 17. - Device according to claim 15, characterized in that it comprises between the carburetor (42) and said pipe a non-return element, such as a valve (26). 18. - Device according to claim 12, characterized in that said fuel introduction and metering member comprises a diaphragm pump (32) actuated by the pressure pulses of a pump housing. 19. - Device according to claim 18, characterized in that the outlet conduit (34) of said diaphragm pump which connects the latter to said pipe (15), comprises a system for adjusting its passage section, this system comprising a needle (37) and control means taking into account the average pressure of a casing. 20. - Device according to claim 1, characterized in that said connecting pipe (15) has a common part with the transfer duct (17R) which connects said pump housing with said lumen. 21. - Device according to claim 20, characterized in that it comprises an aerodynamic profiled part at the interconnection of said pipe, said transfer duct and said transfer lumen. 22. - Device according to claim 20, characterized in that it comprises a non-return valve on said transfer duct, said valve not allowing flow back to the pump housing. 23. - Device according to claim 1, characterized in that said piston is beveled or indented on a part of its surface to allow a return flow through at least one transfer lumen. 24. - Device according to one of the preceding claims, characterized in that said light where said return flow occurs is positioned so that said flow occurs only after at least one exhaust light from said other cylinder has been discovered by said piston of said other cylinder. 25. - Method of introducing under pressure the fuel mixture into a first cylinder of an internal combustion engine, this engine comprising at least one other cylinder having a pump housing, said pump housing communicating with said other cylinder by at least a transfer light, characterized in that the pressure of the gases contained in said pump housing is used as a pressure source for injecting the fuel mixture into the other cylinder, and in that a return flow is caused through said transfer lumen to momentarily increase pressure in said housing or in a transfer conduit.

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