FR3098858A1 - HYDRAULIC CAM INJECTION SYSTEM - Google Patents

Abstract

CAM HYDRAULIC INJECTION SYSTEM The cam hydraulic injection system (100) comprises an injection valve (50) housed in a tubular injection nozzle (54) with a space left between a valve stem (51 ) of said valve (50) and the internal surface of the tubular injection nozzle (54) for allowing an injectable fluid (58) to flow from pressurizing means (10) while a receiving piston (62) integral with of said valve (50) receives on the one hand, the pressure of the injectable fluid (58) to keep said valve (50) closed, and on the other hand, the pressure of a hydraulic fluid (60) to open said valve ( 50), an injection cam (67) being able to set in motion said receiver piston (62) via a transmitter piston (69) and said hydraulic fluid (60). Figure for the abstract: Fig. 1

Description

HYDRAULIC CAM INJECTION SYSTEM

The subject of the present invention is a hydraulic cam injection system provided, among other things, for injecting a pilot charge consisting of a mixture of air and easily flammable fuel into a reed valve ignition prechamber or, more incidentally, into a prechamber formed by a shuttle electrode spark plug.

When said pilot charge is ignited by a spark, said prechamber ejects hot gas flares into the combustion chamber of an internal combustion heat engine in order to ignite a main charge contained in said chamber.

We know the French patent application N FR 17 50264 of January 12, 2017 relating to a valve ignition prechamber, published on July 13, 2018 under No. 3 061 743. We also know the French patent relating to a spark plug shuttle electrode ignition published on May 17, 2019 under N 3 060 222. The two said applications belong to the applicant.

Said application and said patent were jointly the subject of two French patent applications for improvement which also belong to the applicant. The first so-called application dated September 10, 2018 was registered under No. 18 58111 and relates to a magnetic valve return device. The second said request was registered on May 13, 2019 under No. 1904961 and concerns an ignition insert with an active prechamber.

The inventions relating to the aforementioned patent applications and patents apply primarily to any spark-ignition reciprocating engine of any type whatsoever whose main charge is highly diluted with fresh air or with previously cooled recirculated exhaust gases. .

Subject to stable, rapid and sufficiently complete combustion, said highly diluted main charge increases the average and/or maximum thermodynamic efficiency of said engine which receives it compared to that of spark-ignition engines alone and therefore reduces fuel consumption. of fuel from said engine at the same work produced.

It is to achieve this objective of a stable, rapid, and sufficiently complete combustion that the said inventions are intended to produce a powerful, stable and safe ignition without which the expected reduction in fuel consumption cannot be obtained.

It is noted that the inventions relating to the patent and patent applications which have just been cited require an injector which injects directly into the prechamber a mixture of air and fuel, the latter having been pressurized beforehand by a compressor.

It is noted that said injector must be as compact as possible in order to be able to be integrated into the cylinder head of any spark-ignition reciprocating engine without interfering unduly with the intake ducts, with the exhaust ducts, or with the water chambers cooling that includes said cylinder head.

In addition to being compact, it can be seen on reading French patent application No. 1904961 that said injector should advantageously have a nozzle of great length and small diameter. This particular configuration is necessary so that said injector can be integrated into the cylinder head of any spark-ignition reciprocating internal combustion engine without interfering in a prohibitive manner with the functional components and volumes of said cylinder head. This implies in particular to provide an injector provided with a very long needle whose high mass requires a powerful actuator.

The injector in question must also offer high dynamics and permeability. These qualities are necessary to be able to inject the pilot charge into the pre-chamber in the allotted time, whatever the speed and load of the internal combustion engine, and despite the pressure of the air and fuel mixture planned relatively low at the inlet of said injector.

Indeed, reciprocating internal combustion engines with spark ignition are mostly cooled by a water circuit whose temperature is maintained at around one hundred degrees Celsius. It follows from this that preferably, the air and fuel mixture injector provided for by the inventions of French patent application No. FR 17 50264 and of French patent No. 3,060,222 must also be maintained at a temperature n not exceeding one hundred degrees Celsius, in order to avoid any additional device for heating said injector.

However, by way of non-limiting example, if the temperature of the injector does not exceed one hundred degrees Celsius and if the richness of the air-petrol mixture which it injects is 1.2 or 1.3, the pressure said mixture at the inlet of said injector must not exceed fifty bars.

Indeed, beyond this limit pressure, part of the fuel contained in the mixture would condense on the internal walls of the injector and would change from the gaseous state to the liquid state. As a result of exceeding this saturated vapor pressure limit, the fraction of the pilot charge remaining in the gaseous state would be of lower richness, would possibly be difficult to ignite, and its combustion would be potentially unstable. Furthermore, the highly reactive chemical species that result from the combustion of a rich mixture would no longer be produced in the desired quantities, and the flare ignition of the main charge would become less efficient.

Taking into account what has just been said, in order to be able to inject an air-petrol mixture with a richness of 1.2 to 1.3 maintained at one hundred degrees Celsius, the inlet pressure of the injector which is loaded must not to inject the pilot charge into the prechamber described in French patent application No. FR 17 50264 and in French patent No. 3,060,222 exceeds fifty bars. This relatively low pressure must be compensated by a high injector permeability.

To obtain said high permeability, it is not possible to excessively increase the diameter of the injector because the latter would become too bulky. The most appropriate solution consists in significantly increasing the stroke of the injector needle, compared to that of a direct automotive gasoline injector which is around fifty to sixty micrometers.

The problem is that increasing the stroke of the needle requires more than proportionally increasing the size and power of the solenoid actuator that moves said needle. Indeed, raising the needle more in the same time increases the average speed of raising and lowering said needle. This increase in lifting and lowering speed has even more impact on the sizing of the solenoid actuator as the reciprocating internal combustion engine itself rotates at high speed.

In addition, an increased stroke of said needle moves the solenoid vane which actuates said needle away from the stator with which said vane cooperates. As the force exerted by said pallet on said needle decreases approximately due to the square of the distance which separates said pallet from said stator, the constituent coil of the solenoid actuator must produce a very strong magnetic field. This is all the more true as the needle moves far away from its seat, it is necessary to provide a powerful return spring, capable of bringing said needle back to its seat in the allotted time.

Increasing the stroke of the needle therefore leads to an actuator coil whose electrical current requirement penalizes the efficiency of the internal combustion engine, and whose bulk and weight are hardly compatible with the allocatable space in the cylinder head of said engine. In addition, the cost price of such an actuator coil will be potentially incompatible with the economic constraints of large-scale automotive production.

In addition, the high resting speeds of said needle on its seat would produce an excessive power shock which would compromise the durability of said needle and of said seat. The damage caused by said impact would be all the greater if the injector injects a low-density gas mixture whose lubricating properties are practically non-existent.

• De réaliser un injecteur de charge pilote doté d’une buse de grande longueur et de petit diamètre, facilement intégrable à la culasse d’un moteur alternatif à combustion interne ;
• De prévoir une grande levée d’aiguille d’injecteur qui confère à l’injecteur de charge pilote et malgré son petit diamètre une section de passage et une perméabilité de plusieurs dizaines de fois supérieure à celle d’un injecteur direct d’essence conventionnel, de sorte que ledit injecteur de charge pilote assure le remplissage de la préchambre sur toute la plage de fonctionnement du moteur alternatif à combustion interne malgré une pression limitée - par exemple à cinquante bars - du mélange d’air et de carburant en entrée dudit injecteur ;
• De réaliser un injecteur de charge pilote à longue durée de vie malgré une grande levée d’aiguille et malgré que ledit injecteur injecte un mélange gazeux de faible densité aux propriétés lubrifiantes pratiquement inexistantes ;
• De réaliser un injecteur de charge pilote dont le prix de revient est notamment compatible avec la production en grande série automobile ;
• De réduire drastiquement le poids et l’encombrement de l’actionneur qui déplace l’aiguille de l’injecteur de charge pilote, de sorte que ledit actionneur soit aisément logeable à l’intérieur ou à proximité de la culasse de tout moteur alternatif à combustion interne.

It is to solve these various problems that the hydraulic cam injection system according to the invention, in relation to the inventions of French patent application No. FR 17 50264 and of French patent No. 3,060,222 and according to a particular embodiment, allows:

• To produce a pilot charge injector equipped with a nozzle of great length and small diameter, easily integrated into the cylinder head of a reciprocating internal combustion engine;
• To provide a large injector needle lift which gives the pilot charge injector, despite its small diameter, a passage section and a permeability several tens of times greater than that of a conventional direct gasoline injector, so that said pilot charge injector fills the prechamber over the entire operating range of the reciprocating internal combustion engine despite a limited pressure - for example at fifty bars - of the air and fuel mixture at the inlet of said injector;
• To produce a long-life pilot charge injector despite a large needle lift and despite the fact that said injector injects a low-density gas mixture with practically non-existent lubricating properties;
• To produce a pilot charge injector whose cost price is particularly compatible with mass production of automobiles;
• To drastically reduce the weight and bulk of the actuator which moves the needle of the pilot charge injector, so that said actuator can easily be housed inside or near the cylinder head of any reciprocating combustion engine internal.

The applications of the hydraulic cam injection system according to the invention are moreover not limited solely to the inventions relating to French patent application N FR 17 50264 and to French patent N° 3 060 222.

The hydraulic cam injection system according to the invention can in particular inject gas or liquid into any active prechamber with or without a valve, or replace any direct or indirect injector according to the state of the art injecting a gas and / or a pure or compound liquid, whether said injector is implemented in a heat engine of any type whatsoever, or in any other machine with no limit of application.

• Au moins une soupape d’injection qui comprend une queue de soupape et qui se termine par une tulipe, cette dernière exposant une portée d’étanchéité de soupape, ladite soupape étant en tout ou partie logée dans une buse d'injection tubulaire terminée par un siège de soupape d’injection sur lequel peut reposer de façon étanche la portée d’étanchéité de soupape tandis qu’un espace est laissé entre la queue de soupape et la surface interne de la buse d'injection tubulaire pour laisser circuler un fluide injectable mis sous pression par des moyens de mise en pression ;
• Au moins un orifice d’entrée de buse aménagé dans la buse d'injection tubulaire et par lequel le fluide injectable est introduit à l’intérieur de ladite buse ;
• Au moins un cylindre récepteur qui est directement ou indirectement solidaire de l’extrémité de la buse d'injection tubulaire ;
• Au moins un piston récepteur solidaire de la queue de soupape et logé dans le cylindre récepteur, ledit piston pouvant se mouvoir en translation longitudinale dans ledit cylindre et présentant une face axiale côté fluide injectable qui communique avec le volume intérieur de la buse d'injection tubulaire, et une face axiale côté fluide hydraulique qui forme, avec le cylindre récepteur une chambre réceptrice de volume variable remplie d’un fluide hydraulique ;
• Au moins un dispositif d’alimentation en fluide hydraulique relié à la chambre réceptrice et qui permet d’actionner le piston récepteur via le fluide hydraulique par l’intermédiaire d’un conduit hydraulique d'action.

The hydraulic cam injection system includes:

• At least one injection valve which comprises a valve stem and which ends in a tulip, the latter exposing a valve sealing surface, said valve being wholly or partly housed in a tubular injection nozzle terminated by a injection valve seat on which the valve sealing surface can rest sealingly while a space is left between the valve stem and the internal surface of the tubular injection nozzle to allow an injected fluid to circulate under pressure by pressurizing means;
• At least one nozzle inlet orifice provided in the tubular injection nozzle and through which the injectable fluid is introduced inside said nozzle;
• At least one receiver cylinder which is directly or indirectly attached to the end of the tubular injection nozzle;
• At least one receiver piston secured to the valve stem and housed in the receiver cylinder, said piston being able to move in longitudinal translation in said cylinder and having an axial face on the injectable fluid side which communicates with the interior volume of the tubular injection nozzle , and an axial face on the hydraulic fluid side which forms, with the receiving cylinder, a receiving chamber of variable volume filled with a hydraulic fluid;
• At least one hydraulic fluid supply device connected to the receiving chamber and which makes it possible to actuate the receiving piston via the hydraulic fluid via a hydraulic action conduit.

The hydraulic cam injection system according to the present invention comprises a receiver piston return spring which tends to bring the receiver piston closer to a receiver cylinder head .

The hydraulic cam injection system according to the present invention comprises permeable guide means which are directly or indirectly integral with the injection valve and/or the tubular injection nozzle, said means keeping the injection valve approximately centered in the tubular injection nozzle .

The hydraulic cam injection system according to the present invention comprises a hydraulic fluid supply device which consists of an injection cam which has at least one cam profile held directly or indirectly in contact with an axial face of action exhibited by an emitter piston housed in an emitter cylinder, said piston having - opposite the axial action face - an axial face for emitting hydraulic fluid which forms an emitting chamber with the emitter cylinder, while the cam profile can move the transmitter piston in longitudinal translation in the master cylinder when the injection cam is rotated by a driving source.

The hydraulic cam injection system according to the present invention comprises a hydraulic action conduit which connects the emitting chamber to the receiving chamber, said conduit, the emitting chamber and the receiving chamber being filled with hydraulic fluid.

The hydraulic cam injection system according to the present invention comprises a cam profile which comprises at least one angular lifting sector which moves the transmitter piston when said sector is in contact with the axial action face and the cam injection is in rotation, and at least one circular holding angular sector centered on the axis of rotation of said injection cam which immobilizes the transmitter piston when said sector is in contact with the axial action face and this, despite the injection cam is rotating.

The hydraulic cam injection system according to the present invention comprises a cam profile which is kept in contact with the axial action face by means of a rocker arm which bears directly or indirectly on a cam casing in which turns the injection cam.

The hydraulic cam injection system according to the present invention comprises a rocker arm bearing on the cam casing via a movable tipping point whose position between the cam profile and the axial action face can be modified by an injector lift actuator .

The hydraulic cam injection system according to the present invention comprises a displaceable tipping point which consists of a displaceable support roller which can roll on a displacement track provided in the cam housing, said roller cooperating with a track tipping arranged on the back of the rocker arm .

The hydraulic cam injection system according to the present invention comprises a movable support roller which receives at each of its ends an orientation pinion, said pinions being integral in rotation, while each said pinion cooperates with a rack of orientation integral with the cam housing .

The hydraulic cam injection system according to the present invention comprises a movable support roller which receives a worm wheel cooperating with a worm whose axial position is fixed relative to the cam housing, said screw being able to be rotated by the injector lift actuator .

The hydraulic cam injection system according to the present invention comprises an injection cam phase shifter which is interposed between the injection cam and the driving source .

The cam hydraulic injection system according to the present invention comprises a tubular injection nozzle, the end of which terminates in the injection valve seat and is capped with a perforated diffuser .

The hydraulic cam injection system according to the present invention comprises a perforated diffuser of which at least part of its internal wall is cylindrical and leaves a small clearance between itself and the external peripheral surface of the socket so that said diffuser forms the permeable guide means.

The cam hydraulic injection system according to the present invention comprises a boost pump which tends to introduce hydraulic fluid into the hydraulic action conduit via a boost non-return valve, said hydraulic fluid coming from a fluid tank hydraulics .

The description which follows with regard to the appended drawings and given by way of non-limiting examples will make it possible to better understand the invention, the characteristics which it presents, and the advantages which it is likely to provide:

is a schematic sectional view of the hydraulic cam injection system according to the invention such that it can be installed in the cylinder head of an internal combustion engine equipped with a valve ignition prechamber according to the patent application French No. FR 17 50264, and an active pre-chamber ignition insert according to French patent application N 3 060 222.

is a schematic sectional view which shows the angular lifting and holding sectors such that the cam profile of the hydraulic cam injection system according to the invention can receive them.

[Fig. 3 to 5] are schematic cross-sectional views illustrating the operation of the injection cam and of the emitter piston of the cam-operated hydraulic injection system according to the invention, said cam cooperating with a rocker arm whose lever arm can vary depending on the invention. depending on the position of a movable support roller, said position being controlled by an electric stepper motor via a worm screw and a worm wheel.

is a three-dimensional view of the injection cam of the hydraulic cam injection system according to the invention, and of the main functional components shown in FIGS. 3 to 5 with which said cam cooperates.

DESCRIPTION OF THE INVENTION

Figures 1 to 6 show the hydraulic cam injection system 100 according to the invention, various details of its components, its variants, and its accessories.

As shown in Figure 1, cam hydraulic injection system 100 includes at least one injection valve 50 which includes a valve stem 51, and which terminates in a bell that exposes a valve sealing surface.

It is noted in Figure 1 that the valve 50 is wholly or partly housed in a tubular injection nozzle 54 terminated by an injection valve seat on which the valve sealing surface can rest in a leaktight manner, while a space is left between the valve stem 51 and the inner surface of the tubular injection nozzle 54 to allow an injectable fluid 58 to circulate, pressurized by pressurizing means 10. particular embodiment of the cam hydraulic injection system according to the invention, the valve sealing face may be truncated while the injection valve seat is conical.

It will be noted that the hydraulic cam injection system 100 provides permeable guide means which are directly or indirectly integral with the injection valve 50 and/or the tubular injection nozzle 54. Said means keep the valve from injection 50 approximately centered in the tubular injection nozzle 54 regardless of the axial position of said valve 50 relative to said nozzle 54.

It is noted that the permeable guide means may comprise at least one gas passage channel which allows the injectable fluid 58 to circulate between the injection valve 50 and the tubular injection nozzle 54.

It is noted that the hydraulic cam injection system 100 comprises a nozzle inlet orifice arranged in the tubular injection nozzle 54 and through which the injectable fluid 58 is introduced inside said nozzle 54 after having been conveyed via an injectable fluid supply conduit 66 which connects the pressurizing means 10 to said orifice.

It is noted that the connection between the injectable fluid supply conduit 66 and the nozzle inlet orifice can be made by welding, crimping, by means of a "banjo" connector known per se, or by resorting to a connection block of any type.

In addition, the injectable fluid supply duct 66 can receive heating means by electrical resistance, by external circulation of a heat transfer fluid such as water or oil, or by any other means. Said heating means advantageously make it possible to accelerate the rise in temperature of the injectable fluid supply conduit 66 during the start-up of the hydraulic cam injection system 100 according to the invention in a low-temperature environment.

Said means or similar means can also be applied to the hydraulic action conduit 78 and/or to the tubular injection nozzle 54.

As shown particularly in Figure 8, the hydraulic cam injection system 100 comprises at least one slave cylinder which is directly or indirectly integral with the end of the tubular injection nozzle 54 which is located opposite the end of said nozzle 54 which receives the injection valve seat, said receiver cylinder being positioned in the extension of said nozzle 54.

Also, the figures show that the hydraulic cam injection system 100 comprises at least one receiving piston 62 integral with the valve stem 51 and housed in the receiving cylinder, said piston 62 being able to move in longitudinal translation in said cylinder and having an axial face on the injection fluid side which communicates with the interior volume of the tubular injection nozzle 54, and an axial face on the hydraulic fluid side which forms, with the receiver cylinder and a receiver cylinder head which terminates said cylinder, a receiver chamber 71 of volume variable.

It is noted that the receiver piston 62 can be made in one or more parts, and that it can receive a seal of any type whatsoever and in particular, a composite seal having a low coefficient of friction and a high resistance to abrasion. This particular configuration can also be applied to the transmitter piston 69.

In FIGS. 1 to 6, it is noted that the hydraulic cam injection system 100 comprises a hydraulic fluid supply device consisting of at least one injection cam 67 which has at least one cam profile 68 maintained directly or indirectly in contact with an axial action face 75 presented by an emitter piston 69 housed in an emitter cylinder 70.

It is noted, particularly in Figures 3 to 6, that said piston 69 has - opposite the axial face of action 75 - an axial face of hydraulic fluid emission 76 which forms an emitting chamber 72 with the emitter cylinder 70 and a master cylinder head 77 which terminates said cylinder 70, while the cam profile 68 can move the master piston 69 in longitudinal translation in the master cylinder 70 when the injection cam 67 is rotated by a driving source 73.

The driving source 73 can take the form of an electric motor, a hydraulic motor, the crankshaft of an internal combustion engine 2, or any other driving source 73 to which the injection cam 67 is connected by any transmission type whether it is a shaft, a toothed belt or not, a chain, or sprockets.

It will be noted that if the injection cam 67 is driven by the crankshaft of an internal combustion engine 2, it can be integral with the camshaft of said engine 2, or placed at the end of the central shaft of a air compressor which forms the pressurizing means 10, or receive its own pulley which is driven by the timing belt of said engine 2.

It is noted in Figure 1 that the hydraulic cam injection system 100 comprises at least one hydraulic action conduit 78 which connects the emitting chamber 72 to the receiving chamber 71, said conduit 78, the emitting chamber 72 and the receiving chamber 71 being filled with a hydraulic fluid 60.

A receiver piston return spring may be provided which tends to bring the receiver piston 62 closer to the receiver cylinder head, which has the effect of tending to maintain the valve sealing surface in contact with the injection valve seat.

Said spring can for example be housed in the slave cylinder and/or in the tubular injection nozzle 54 and be helical, formed by a stack of spring washers or be of any type known to those skilled in the art. Note that a similar return spring can tend to bring the transmitter piston 69 closer to the transmitter cylinder head 77.

As clearly illustrated in FIG. 2, the cam profile 68 may comprise at least one angular lifting sector 15 which moves the transmitter piston 69 when said sector 15 is in contact with the axial action face 75 and the cam d injection 67 is rotating, and at least one angular holding sector 16 is circular and centered on the axis of rotation of said injection cam 67 which immobilizes emitter piston 69 when said sector 16 is in contact with the axial face of action 75 and this, despite that the injection cam 67 is rotating.

It will be noted that the difference in radius of the cam profile 68 between that found at the level of the angular sector of maintenance 16 and that maximum found at the level of the angular sector of lift 15 determines the lift L produced by the injection cam 67 at the level of the cam profile 68. Taking into account any mechanical and/or hydraulic lever arms, said value L corresponds to a higher or lower lift of the injection valve 50.

As an alternative embodiment of the hydraulic cam injection system 100 according to the invention shown in FIG. 1 and in FIGS. 3 to 6, the cam profile 68 can be kept in contact with the axial action face 75 by the intermediary of a rocker arm 80 which bears directly or indirectly on a cam housing 81 in which the injection cam 67 rotates.

It is noted in FIG. 1 and in FIGS. 3 to 6 that, advantageously, the rocker arm 80 can be kept in contact with the cam profile 68 by means of a latch roller 86 known per se which limits friction losses to the interface between said rocker arm 80 and said cam profile 68.

It is also noted in FIG. 1 and in FIGS. 3 to 6 that according to a particular embodiment of the hydraulic cam injection system 100 according to the invention, the rocker arm 80 can be maintained in contact either with the cam profile 68, or with the axial action face 75 by a rocker arm return spring 14.

In addition, the rocker arm 80 can cooperate with guide means not shown arranged in the cam housing 81 so that said rocker arm 80 cannot rotate around an axis perpendicular to its operational tilting axis.

In FIG. 1 and in FIGS. 3 to 6, it will be noted that the rocker arm 80 can bear on the cam housing 81 via a movable tipping point 82 whose position between the cam profile 68 and the axial face action 75 can be changed by an injector lift actuator 83.

As can easily be deduced from FIG. 1 and FIGS. 3 to 6, for the same cam profile 68, the position of the displaceable tipping point 82 determines the amplitude of displacement of the axial action face 75 and therefore, the lift height of the injection valve 50 relative to the injection valve seat with which it cooperates.

Consequently, if the tubular injection nozzle 54 opens into a volume at constant pressure, for a given speed of rotation of the injection cam 67 and for a given pressure of the injectable fluid 58 in the conduit for supplying injectable fluid 66, the greater the height of lift of the injection valve 50, the greater the quantity of injectable fluid 58 expelled from the tubular injection nozzle 54 via the passage left between the valve sealing surface and the valve seat injection is important.

FIG. 1 and FIGS. 3 to 6 show that, advantageously, the displaceable tipping point 82 can consist of a displaceable support roller 84 which can roll on a displacement track 85 provided in the cam housing 81, said roller 84 cooperating with a tilting track 87 arranged on the back of the rocker arm 80.

It can be seen in FIG. 1 and in FIGS. 3 to 6 that, advantageously, the rocker arm 80 can be articulated around a ball joint 88 secured to the axial action face 75. As a refinement, the latch roller 86 can have barrel-shaped exterior. According to this particular configuration, the displacement track 85 and the tilting track 87 can be perfectly flat and the movable support roller 84 perfectly cylindrical. This non-limiting configuration makes it possible to avoid any hyperstatic relationship between the various parts 84, 85, 86, 87 which have just been listed, while avoiding having to produce a cam profile 68 whose outer axial surface is curved. .

Figure 6 clearly shows that the movable support roller 84 can receive at each of its ends an orientation pinion 89, said pinions 89 being integral in rotation, while each said pinion 89 cooperates with an orientation rack 90 integral of the cam housing 81.

This particular configuration makes it possible to keep the movable support roller 84 perpendicular to the displacement track 85 with which it cooperates, and this regardless of the position of said roller 84 with respect to said track 85.

Figure 6 also clearly shows that the movable support roller 84 can receive a worm wheel 91 which cooperates with a worm 92 whose axial position is fixed relative to the cam housing 81. In this case, said screw 92 can be rotated by the injector lift actuator 83 which can be, as shown in Figure 1 and Figures 3 to 6, a stepper electric motor 93 with or without a reduction gear of any type and driven by an ECU.

It will be noted that the stepper electric motor 93 just like any injector lift actuator 83 can be connected to the endless screw 92 directly or via a transmission by belt, chain, sprockets , or any type known to those skilled in the art.

Thus, when the injector lift actuator 83 rotates the worm screw 92, the movable support roller 84 moves relative to the displacement track 85 with which it cooperates, which has the effect of moving the position of the displaceable tipping point 82 with respect to the cam housing 81. This makes it possible to regulate the quantity of injectable fluid 58 expelled from the tubular injection nozzle 54.

It will be noted that the same movable support roller 84 can cooperate with several rocker arms 80 to simultaneously vary the lever arm thereof, just as the same electric stepper motor 93 can move several movable support rollers 84.

In FIG. 1, it has been shown that an injection cam phase shifter 96 can be interposed between the injection cam 67 and the driving source 73, said phase shifter 96 making it possible to advance or retard angularly with respect to the source. drive 73 the movement imparted by the injection cam 67 to the transmitter piston 69, for example when said source 73 consists of the crankshaft of an engine with an internal combustion engine 2.

It will be noted that the principle of the injection cam phase shifter 96 may be similar to that of the hydraulic or electric camshaft phase shifters of automobile internal combustion engines.

It has been shown that the end of the tubular injection nozzle 54 which terminates in the injection valve seat can be capped with a perforated diffuser which forces the injectable fluid 58 expelled from the tubular injection nozzle 54 via the passage left between the valve sealing surface and the injection valve seat to pass through one or more ejection orifices so as to create jets of injectable fluid 58.

According to this variant of the hydraulic cam injection system 100 according to the invention, at least part of the internal wall of the perforated diffuser can be cylindrical and leave a small clearance between itself and the external peripheral surface of the so that said diffuser forms the permeable guide means.

Finally, FIG. 1 shows that a booster pump 7 can be provided which tends to introduce hydraulic fluid 60 into the hydraulic action conduit 78 via a booster non-return valve 8, said hydraulic fluid 60 coming from a hydraulic fluid tank 11.

It is noted that according to a particular embodiment of the hydraulic cam injection system 100 according to the invention, the booster pump 7 may consist of the lubricating pump of an internal combustion engine 2 while the fluid tank 11 consists of the oil sump of said engine 2. It should also be noted that the hydraulic action duct 78 may comprise a pressure limiter and purge devices known per se.

OPERATION OF THE INVENTION:

The operation of the hydraulic cam injection system 100 according to the invention is easily understood.

To detail the operation of said system 100, we apply it here to the valve ignition prechamber which was the subject of French patent application No. FR 17 50264, said prechamber receiving on the one hand, the magnetic valve return object of French patent application No. 18 58111, and on the other hand, the ignition insert with active prechamber object of French patent application No. 1904961.

FIG. 1 shows the hydraulic cam injection system 100 which, according to this non-limiting example, equips an internal combustion engine 2 which notably comprises a cylinder 4 capped with a cylinder head 3, said cylinder 4 and said cylinder head 3 forming, with a piston 31, a combustion chamber 5.

In Figure 1 we see the valve ignition prechamber 1 arranged in an active prechamber ignition insert 6 housed in the cylinder head 3. We also note in said Figure 1 that the tubular injection nozzle 54 and the valve injection 50 open into the valve ignition prechamber 1 in order to be able to introduce therein an injectable fluid 58 which, according to this example, consists of an AF mixture of air and easily flammable gasoline.

Said AF mixture forms a pilot charge 9 which is intended to be ignited by a spark plug 12 which opens into the valve ignition prechamber 1. Once ignited, said pilot charge 9 will be ejected via orifices ejection of the gases 24 into the combustion chamber 5, in the form of high temperature gas flares. Said torches are provided to ignite a main load 30 contained in said combustion chamber 5.

In Figure 1, it is noted that the valve ignition prechamber 1 and the combustion chamber 5 are separated by a valve 13 which is returned to its seat by a permanent magnet 49 which is part of the valve magnetic return device 42 as described in French patent application No. 18 58111 belonging to the applicant. Said valve 13 allows the gases contained in the valve ignition prechamber 1 to go into the combustion chamber 5 but it prevents the gases contained in the said chamber 5 from entering the valve ignition prechamber 1.

When it is closed, the valve 13 makes the valve ignition prechamber 1 a closed volume in which there is a pressure and a temperature lower than those prevailing in the combustion chamber 5. This eliminates any risk of self-ignition. of the pilot load 9 in said prechamber 1.

The valve 13 being closed, the tubular injection nozzle 54 can inject into the valve ignition prechamber 1 the necessary easily flammable pilot charge 9 without risk of mixing the latter with the main charge 30 which, on the contrary being difficult to ignite, must be brought to a higher pressure and temperature to allow and promote ignition.

Note that the particular configuration shown in Figure 1 of the cylinder head 3 and the ignition insert with active prechamber 6 requires a tubular injection nozzle 54 of great length. The latter is incompatible with the technological and production constraints of the compact and economical injectors usually used in automobiles. However, said great length does not pose any particular problem if the cam-operated hydraulic injection system 100 according to the invention is used.

We will make the assumption here that the pressure of the injectable fluid 58 supplied to the tubular injection nozzle 54 by the pressurizing means 10 is fifty bars. This pressure must not be exceeded because the injectable fluid 58 consists of a gaseous mixture of air and gasoline AF. Indeed, the injectable fluid 58 is maintained at a temperature of one hundred degrees Celsius. Said temperature is imposed by the water which circulates in the cooling water chambers 41 of the cylinder head 3 of the internal combustion engine 2. However, if at such a temperature the pressure of the injectable fluid 58 exceeded fifty bars, part of the gasoline constituting the gas mixture AF would inevitably condense.

Recall that the tubular injection nozzle 54 injects the injectable fluid 58 into the valve ignition prechamber 1 to form the pilot charge 9 during the compression stroke of the internal combustion engine 2, taking care that the pressure in said prechamber 1 always remains lower than the pressure in the combustion chamber 5.

This constraint leads to a duration of injection of the pilot charge 9 limited for example to forty degrees of crankshaft of the internal combustion engine 2.

The constraints of length, temperature and pressure which have just been described give all its interest to the hydraulic cam injection system 100 according to the invention. Indeed, said system 100 makes it possible to produce a long and compact tubular injection nozzle 54, capable of injecting in less than forty crankshaft degrees the pilot charge 9 necessary in the reed valve ignition prechamber 1, this despite a upstream pressure of the injectable fluid 58 limited to fifty bars due to its temperature limited to one hundred degrees Celsius.

To achieve this result, it is noted that the section exposed to the pressure of the injectable fluid 58 of the axial face on the injectable fluid side of the receiving piston 62 is provided greater than the section exposed by the tulip of the injection valve 50 to said pressure when said valve 50 rests on the injection valve seat with which it cooperates.

Consequently, the pressure which prevails in the tubular injection nozzle 54 tends to press the valve sealing face against the injection valve seat, and to maintain the injection valve 50 closed, aided in this by the slave piston return spring. This significant return force produced by the pressure of the injectable fluid 58 makes it possible to avoid having to resort to a high-power receiver piston return spring which would be heavy and cumbersome.

It will be assumed, in relation to FIG. 1, that the booster pump 7 which supplies the hydraulic action conduit 78 with hydraulic fluid 60 via the booster non-return valve 8 is none other than the engine lubrication pump. internal combustion 2 while the hydraulic fluid tank 11 consists of the oil sump of said engine 2.

In this context, advantageously, the force produced by the receiver piston return spring is provided to be substantially greater than the force produced by the pressure generated by the lubrication pump of the internal combustion engine 2 on the receiver piston 62.

We also note in Figure 1 that the injection fluid supply conduit 66 is here fitted directly into the foundry of the cylinder head 3 while the injection cam 67 is driven by the camshaft of the internal combustion engine 2.

It will be assumed here that, as shown in FIG. 1 and in FIGS. 3 to 6, the cam profile 68 of the injection cam 67 is kept in contact with the axial action face 75 of the emitter piston 69 by means of a rocker arm 80, the latter being held in contact with the cam profile 68 by means of a latch roller 86.

As illustrated in Figure 1 and Figures 3 to 6, it will also be assumed that the rocker arm 80 bears on the cam housing 81 via a movable support roller 84 which can roll on a displacement track 85 provided in the cam housing 81, said roller 84 cooperating with a tilting track 87 arranged on the back of the rocker arm 80.

In Figures 1 and in Figures 3 to 6, it is noted that advantageously the displacement track 85 is perfectly perpendicular to the axis of the transmitter piston 69. In addition, in Figures 1, 3, 5 and 6, it is noted that when the latch roller 86 is in contact with angular holding sector 16 and that transmitter piston 69 pushes on rocker arm 80 via its axial action face 75 to press said rocker arm 80 onto displacement track 85 via the movable support roller 84, the tilting track 87 of said rocker arm 80 remains parallel to the displacement track 85 whatever the position of the movable support roller 84.

It is noted in this respect that it is possible to provide a screw or cam adjustment device or any other adjustment means which makes it possible to adjust the perpendicularity of the displacement track 85 with respect to the axis of the transmitter piston 69 and/or the displacement of the displacement track 85 relative to the injection cam 67 along an axis parallel to that of the emitter piston 69.

To counter any inaccuracy of the settings which have just been described, provision may advantageously be made for a little hydraulic fluid 60 to escape directly or indirectly from the hydraulic action conduit 78 at each opening cycle of the injection valve. 50. This can take place for example via the emitter piston 69, the sealing of which is imperfect, or via a nozzle of very small section placed at any point of the circuit which connects the emitter chamber 72 to the receiver chamber 71, said nozzle escaping some hydraulic fluid 60 which returns to the hydraulic fluid reservoir 11.

It is noted, particularly in Figure 6, that the movable support roller 84 receives at each of its ends an orientation pinion 89, said pinions 89 being integral in rotation, while each said pinion 89 cooperates with an orientation rack 90 integral with the cam housing 81.

It is also noted that the movable support roller 84 receives a worm wheel 91 which cooperates with a worm 92 whose axial position is fixed relative to the cam housing 81, said screw 92 being driven in rotation by the injector lift actuator 83 which, according to this non-limiting example, consists of a stepper electric motor 93.

It will be noted that advantageously, the diameter of the pitch circle of the orientation pinions 89 and that of the worm wheel 91 are identical.

Thus, when the stepper electric motor 93 rotates the worm 92, the movable support roller 84 moves relative to the displacement track 85 with which it cooperates, which has the effect of moving the position of the displaceable tilting point 82 with respect to the cam housing 81.

This makes it possible to adjust the quantity of injectable fluid 58 expelled from the tubular injection nozzle 54 towards the valve ignition prechamber 1.

When the internal combustion engine 2 is running, the injection valve 50 is for example first kept closed by the receiver piston 62 due to the pressure which prevails in the tubular injection nozzle and, to a lesser extent, by the slave piston return spring. This situation is illustrated by figures 1, 3 and 6.

As shown in Figure 4, with the internal combustion engine 2 continuing to rotate, the cam profile 68 pushes on the rocker arm 80. The latter tilts and moves the transmitter piston 69 which, in turn, forces hydraulic fluid 60 to pass from the emitting chamber 72 to the receiving chamber 71. This has the effect of moving the receiving piston 62 and moving the valve sealing surface away from the injection valve seat, which has the consequence of transferring injectable fluid 58 from the tubular injection nozzle 54 to the valve ignition prechamber 1.

Figure 5 shows for its part that to adjust the height of lift of the injection valve 50, the stepper electric motor 93 can bring the movable support roller 84 closer or further from the transmitter piston 69 via of the endless screw 92, this to modify the lever arm of the rocker arm 80 and therefore, the displacement ratio between that of the transmitter piston 69 and that of the receiver piston 62.

In practice, the displacement ratio between the displacement of the transmitter piston 69 and the effective lift of the injection valve 50 depends on the lever arm formed by the rocker arm 80, but also on the compressibility of the hydraulic fluid 60 contained in the chamber. transmitter 72, the receiver chamber 71 and the hydraulic action conduit 78.

The force that the rocker arm 80 must apply to the axial action face 75 of the emitter piston 69 is in particular dependent on the pressure of the injectable fluid 58 which prevails in the tubular injection nozzle 54 and on the ratio between the section exposed to the pressure of the injectable fluid 58 by the axial face on the injectable fluid side and the section exposed to said pressure by the socket.

To a lesser extent, said force is also dependent on the force produced by the receiver piston return spring. Added to this is the inertia of the various moving parts and the energy losses they produce by rubbing against each other, and the pressure drops produced by the hydraulic fluid 60 by circulating in particular in the hydraulic action conduit 78.

However, at each operating point of the internal combustion engine 2 there corresponds a position of the stepper electric motor 93 which makes it possible to introduce into the reed valve ignition prechamber 1 the quantity of pilot charge 9 most favorable to efficiency. thermodynamics of said motor 2. Finding the existing relationship between the position of the stepper electric motor 93 and the quantity of pilot load 9 can be carried out on the test bench for each operating point of the internal combustion engine 2, which avoids developing a predictive numerical model, useless in this context.

Consequently, the position of the stepper electric motor 93 is provided to vary according to the needs, and in particular according to the speed, the load, and the dilution of the main load 30 of the internal combustion engine 2. With regard to said dilution, it is noted that the more the main charge 30 is diluted with fresh air or with recirculated exhaust gases, the more it is resistant to ignition, and the more the energy contained in the charge pilot 9 must be large relative to that contained in the main load 30.

Furthermore, to introduce the same quantity of pilot charge 9, the faster the internal combustion engine 2 rotates, the higher the lift of the injection valve 50 must be. Indeed, for the same position of the movable support roller 84, the faster said motor 2 rotates, the shorter the absolute duration of the lifting of the injection valve 50, this to inject the same mass of injectable fluid 58 into the reed valve ignition prechamber 1. The reduction in the injection duration must therefore be compensated by an increase in the passage section left between the valve sealing face and the injection valve seat and therefore, by an increase in the lift height of the injection valve 50.

It is also noted that the internal combustion engine 2 rotating quickly, the effects of the compressibility of the hydraulic fluid 60 are more marked due to the increased acceleration of the parts to be moved and the increase in the peak pressure reached by said fluid 60 resulting. This effect is also to be compensated by an appropriate position of the movable support roller 84 via the stepper electric motor 93.

The map of the ideal position of the stepper electric motor 93 taking into account the operating conditions of the internal combustion engine 2 is stored in the memory of the computer 48, corrected or not by algorithms taking into account the contextual operating parameters such as temperature or aging.

It will be noted that when the internal combustion engine 2 starts at very low temperature - for example minus thirty degrees Celsius - the pressure of the injectable fluid 58 prevailing in the injectable fluid supply conduit 66 and in the tubular injection nozzle 54 must be drastically reduced, for example to five bars instead of fifty bars.

This lower pressure makes it possible not to condense the petrol constituting the air-petrol mixture AF, and to keep its nominal richness in said mixture. It follows from this that during the temperature rise phase of the internal combustion engine 2, the maximum load of the latter is limited to approximately ten bars of average effective pressure, which makes any motor vehicle equipped with it immediately usable.

A few seconds later, the rapid rise in temperature of the pressurizing means 10, of the injectable fluid supply conduit 66, and of the tubular injection nozzle 54 allows normal operation to be regained with a pressure of the injectable fluid 58 in the tubular injection nozzle 54 reaching approximately fifty bars.

The example of operation which has just been given of the hydraulic cam injection system 100 according to the invention is in no way limiting. Indeed, said system is capable of allowing the direct or indirect injection of natural gas, heavy fuel oil, diesel or gasoline into any internal combustion engine 2, whatever the principle.

In general, the hydraulic cam injection system 100 according to the invention is capable of allowing the injection of any gas and/or any liquid into any machine requiring such injection, whether or not controlled by a lift actuator. injector 83.

Also, the possibilities of the hydraulic cam injection system 100 according to the invention are not limited to the applications which have just been described and it must moreover be understood that the preceding description has only been given 'by way of example and that it does not in any way limit the field of said invention from which one would not leave by replacing the details of execution described by any other equivalent.

Claims (15)

Cam hydraulic injection system (100),characterized in that'He understands :

• At least one injection valve (50) which comprises a valve stem (51) and which ends in a bell, the latter exposing a valve sealing surface, said valve (50) being wholly or partly housed in a tubular injection nozzle (54) terminated by an injection valve seat on which the valve sealing face can be seated while a space is left between the valve stem (51) and the surface inside the tubular injection nozzle (54) to allow an injectable fluid (58) to circulate, pressurized by pressurizing means (10);
• At least one bus inlet orifice provided in the tubular injection nozzle (54) and through which the injectable fluid (58) is introduced inside said nozzle (54);
• At least one slave cylinder which is directly or indirectly attached to the end of the tubular injection nozzle (54);
• At least one receiver piston (62) secured to the valve stem (51) and housed in the receiver cylinder, said piston (62) being able to move in longitudinal translation in said cylinder and having an axial face on the injection fluid side which communicates with the internal volume of the tubular injection nozzle (54), and an axial face on the hydraulic fluid side which forms, with the receiving cylinder, a receiving chamber (71) of variable volume filled with a hydraulic fluid (60);
• At least one hydraulic fluid supply device connected to the receiving chamber (71) and which makes it possible to actuate the receiving piston (62) via the hydraulic fluid (60) via a hydraulic action conduit ( 78).

Hydraulic cam injection system according to Claim 1, characterized in that a receiver piston return spring tends to bring the receiver piston (62) closer to a receiver cylinder head. Hydraulic cam injection system according to Claim 1, characterized in that permeable guide means are directly or indirectly attached to the injection valve (50) and/or to the tubular injection nozzle (54), said means keeping the injection valve (50) approximately centered in the tubular injection nozzle (54) . Hydraulic cam injection system according to claim 1,characterized in thatTHE hydraulic fluid supply device consists of an injection cam (67) which has at least one cam profile (68) held directly or indirectly in contact with an axial action face (75) which a piston has emitter (69) housed in an emitter cylinder (70), said piston (69) having - opposite the axial action face (75) - an axial face for emitting hydraulic fluid (76) which forms a emitter chamber (72) with the emitter cylinder (70) while the cam profile (68) can move the emitter piston (69) in longitudinal translation in the emitter cylinder (70) when the injection cam (67) is set in rotation by a motive source (73). Hydraulic cam injection system according to any one of Claims 1 to 4, characterized in that the hydraulic action conduit (78) connects the emitting chamber (72) to the receiving chamber (71), the said conduit (78 ), the emitter chamber (72) and the receiver chamber (71) being filled with the hydraulic fluid (60). Hydraulic cam injection system according to Claim 4, characterized in that the cam profile (68) comprises at least one angular sector of lift (15) which moves the transmitter piston (69) when the said sector (15) is at contact with the axial action face (75) and that the injection cam (67) is rotating, and at least one angular holding sector (16) that is circular and centered on the axis of rotation of said injection (67) which immobilizes the transmitter piston (69) when said sector (16) is in contact with the axial action face (75) and this, despite that the injection cam (67) is rotating. Hydraulic cam injection system according to Claim 4, characterized in that the cam profile (68) is kept in contact with the axial action face (75) by means of a rocker arm (80) which takes directly or indirectly bearing on a cam housing (81) in which the injection cam (67) rotates. Hydraulic cam injection system according to Claim 7, characterized in that the rocker arm (80) bears on the cam housing (81) via a displaceable tilting point (82) whose position between the cam profile (68) and the axial action face (75) can be modified by an injector lift actuator (83) . Hydraulic cam injection system according to Claim 8, characterized in that the displaceable tipping point (82) consists of a displaceable support roller (84) which can roll on a displacement track (85) provided in the cam housing (81), said roller (84) cooperating with a tilting track (87) arranged on the back of the rocker arm (80) . Hydraulic cam injection system according to Claim 9, characterized in that the movable support roller (84) receives at each of its ends an orientation pinion (89), the said pinions (89) being integral in rotation, while each said pinion (89) cooperates with an orientation rack (90) secured to the cam housing (81) . Hydraulic cam injection system according to Claim 10, characterized in that the movable support roller (84) receives a worm wheel (91) which cooperates with a worm (92) whose axial position is fixed relative to the cam housing (81), said screw (92) being rotatable by the injector lift actuator (83) . Hydraulic cam injection system according to Claim 4, characterized in that an injection cam phase shifter (96) is interposed between the injection cam (67) and the driving source (73) . Hydraulic cam injection system according to Claim 1, characterized in that the end of the tubular injection nozzle (54) which terminates in the injection valve seat is capped with a perforated diffuser . Hydraulic cam injection system according to Claim 13, characterized in that at least part of the internal wall of the perforated diffuser is cylindrical and leaves a small clearance between itself and the external peripheral surface of the socket so that said diffuser forms the permeable guide means. Hydraulic cam injection system according to Claim 1, characterized in that a booster pump (7) tends to introduce hydraulic fluid (60) into the hydraulic action conduit (78) via a non-return valve of feeding (8), said hydraulic fluid (60) coming from a hydraulic fluid tank (11) .