CN114051554A

CN114051554A - Hydraulic cam injection system

Info

Publication number: CN114051554A
Application number: CN202080045699.7A
Authority: CN
Inventors: V·拉比
Original assignee: V labi
Current assignee: V labi
Priority date: 2019-07-18
Filing date: 2020-07-16
Publication date: 2022-02-15
Also published as: FR3098868A1; JP2022541109A; AU2020315180A1; FR3098868B1; CA3144505A1; FR3098857B1; KR20220034796A; FR3098857A1; EP3999734A1; FR3098858A1; WO2021009466A1; FR3098858B1

Abstract

Hydraulic cam injection system (100) comprising an injection valve (50) housed in a tubular injection nozzle (54), leaving a gap between a valve stem (51) of said valve (50) and an inner surface of said tubular injection nozzle (54) to allow an injectable fluid (58) to flow from a pressurized member (10), whereas on the one hand a housing piston (62) rigidly connected to said valve (50) houses the pressure of said injectable fluid (58) to keep said valve (50) closed and on the other hand said housing piston houses the pressure of a hydraulic fluid (60) to open said valve (50), an injection cam (67) being able to move said housing piston (62) through a transmission piston (69) and said hydraulic fluid (60).

Description

Hydraulic cam injection system

The object of the present invention is a hydraulic injection system with a cam, designed in particular to inject a pilot charge consisting of a mixture of air and combustible fuel into a valve ignition prechamber or, by the way, into a prechamber formed by a spark plug with a shuttle-shaped electrode.

When the pilot charge is ignited by a spark, the pre-chamber ejects a flame of hot gases into a combustion chamber of an internal combustion engine so as to ignite a main charge contained in the chamber.

French patent application No. FR 1750264, published at 3061743, 7/13, 2018, on 12/1, 2017, relating to a valve ignition prechamber, is known. French patent relating to a shuttle-electrode spark plug, published in 2019 on 5, 17 and 3060222, is also known. Both applications belong to the applicant.

Said application and said patent are together the subject of two french improved patent applications also belonging to the present applicant. The first said application, dated 2018, 9/10, registered No. 1858111 and related to a magnetic circuit device for a valve. The second said application was registered at 13.5.2019 under 1904961 and relates to an ignition insert with an active prechamber.

The inventions related to the above patent applications and patents are primarily applicable to any type of reciprocating spark ignition engine where the main charge is heavily diluted with fresh air or pre-cooled recirculated exhaust gas.

The highly diluted main charge improves the average and/or maximum thermodynamic efficiency of the engine housing the main charge compared to the average and/or maximum thermodynamic efficiency of an engine using spark ignition alone, and thus reduces the fuel consumption of the engine for the same work produced, with stable, rapid and fully complete combustion.

It is to achieve this goal of stable, rapid and fully complete combustion that the described invention is designed to produce a robust, stable and safe ignition that would otherwise not achieve the desired reduction in fuel consumption.

It can be seen that the inventions related to the above patents and patent applications require injectors that inject a mixture of air and fuel directly into the pre-chamber, the fuel being pre-pressurized by the compressor.

It should be noted that the injector must be as compact as possible in order to be integrated into the head of any reciprocating spark-ignition engine without excessively disturbing the intake ducts, the exhaust ducts or the cooling water chamber contained in the head.

In addition to being compact, it can be seen from french patent application No. 1904961 that the injector must advantageously have a nozzle with a large length and a small diameter. This particular configuration is necessary so that the injector can be integrated into the head of any reciprocating internal combustion engine with spark ignition, without inefficiently interfering with the functional mechanics and volume of the head. In particular, this means providing an injector provided with an injector needle of large length, which requires a powerful actuator.

The injectors in question must also provide high dynamic properties and permeability. These qualities are necessary in order to be able to inject the pilot charge into the prechamber within a given time, regardless of the speed and load of the internal combustion engine and despite the relatively low pressure of the air and fuel mixture at the injector inlet provided.

This is because most reciprocating internal combustion engines with spark ignition are cooled by a water circuit, the temperature of which is kept at about one hundred degrees celsius. It is therefore preferred that the air and fuel mixture injector provided in the inventions of french patent application FR 1750264 and french patent 3060222 must also be maintained at a temperature not exceeding one hundred degrees celsius to avoid any additional means for heating the injector.

However, as a non-limiting example, if the temperature of the injector does not exceed one hundred degrees celsius, and if the richness of the air-fuel mixture it injects is 1.2 or 1.3, the pressure of said mixture at the inlet of said injector must not exceed fifty bars.

In fact, beyond this limit pressure, a portion of the fuel contained in the mixture will condense on the inner walls of the injector and pass from the gaseous state to the liquid state. As a result of this saturated vapour limit pressure being exceeded, the richness of the fraction of the pilot charge that remains in the gaseous state will decrease, it will likely be difficult to ignite, and its combustion may be unstable. In addition, the highly reactive chemicals produced by the rich mixture combustion will no longer be produced in the desired amount and the main charge flame ignition will become less effective.

In view of what has just been said, the pressure at the inlet of the injector, described in french patent application N ° FR 1750264 and french patent No. 3060222, which must inject the pilot charge into the pre-chamber, must not exceed fifty bars in order to be able to inject an air-fuel mixture with a richness of 1.2 to 1.3 kept at one hundred degrees celsius. This relatively low pressure must be compensated by the high permeability of the ejector.

To achieve such a high permeability it is not possible to increase the diameter of the injector too much, since this would make the injector too bulky. The most suitable solution is to significantly increase the stroke of the injector needle compared to the stroke of a direct gasoline injector, which is about fifty to sixty microns.

The problem is that increasing the needle stroke requires more than just a proportional increase in the size and power of the solenoid actuator that moves the needle. In fact, further raising the needle during the same period of time increases the average speed of raising and lowering the needle. This increase in lift and rest speed has a greater impact on the sizing of the solenoid actuator that the reciprocating internal combustion engine itself operates at high speeds.

In addition, the increased travel of the needle moves a solenoid blade that actuates the needle away from a stator that cooperates with the blade. Because the force exerted by the blade on the needle is reduced approximately as the square of the distance between the blade and the stator, the constituent coils of a solenoid actuator must produce a very strong magnetic field. This is especially true when the needle is removed from its seat, and a strong return spring must be provided that is capable of bringing the needle back to its seat in a given time.

Thus, increasing the stroke of the needle can result in the current demand of the actuator coil being detrimental to the efficiency of the internal combustion engine, and its size and weight are nearly incompatible with the available clearance in the cylinder head of the engine. Furthermore, the cost price of such actuator coils may be incompatible with the economic constraints of mass production of automobiles.

Furthermore, the high resting speed of the needle on its seat generates an excessive dynamic impact which impairs the durability of the needle and of the seat. The damage caused by such an impact is greater since the lubricating properties of the low-density gaseous mixture injected by the injector are almost non-existent.

In order to solve these different problems, the hydraulic injection system with cams according to the invention related to the invention disclosed in french patent application FR 1750264 and french patent 3060222 and according to a particular implementation makes it possible to:

● creating a pilot charge injector with a long length and small diameter nozzle that is easy to integrate into the cylinder head of a reciprocating internal combustion engine;

●, which provides a large injector needle lift that, despite its small diameter, makes the channel cross-section and permeability of the pilot charge injector several tens of times greater than those of a conventional direct gasoline injector, so that the pilot charge injector ensures filling of the pre-chamber throughout the operating range of a reciprocating internal combustion engine, despite the limited pressure of the air and fuel mixture at the inlet of the injector, for example at fifty bar;

● produce a pilot charge injector with long service life despite high needle lift and despite the fact that the low density gaseous mixture injected by the injector does not have lubricating properties;

● lead charge injectors with cost price particularly compatible with mass production in the automotive industry;

● greatly reduce the weight and size of the actuator moving the pilot charge injector needle so that it can be easily housed in or near the cylinder head of any reciprocating internal combustion engine.

The application of the hydraulic injection system with cam according to the present invention is not limited to the inventions related to french patent application No. FR 1750264 and french patent No. 3060222.

The hydraulic injection system with cams according to the present invention can in particular inject gas or liquid into any active prechamber with or without valves, or replace any direct or indirect injector according to the prior art that injects pure or complex gases and/or liquids, whether for any type of heat engine or for any other machine without application limitations.

A hydraulic injection system with a cam includes:

● at least one injection valve comprising a valve stem and terminating in an enlarged portion or funnel forming a valve sealing surface, the valve being wholly or partially housed in a tubular injection nozzle terminating in an injection valve seat on which the valve sealing surface can sealingly rest whilst forming a gap between the valve stem and an inner surface of the tubular injection nozzle to allow the flow of an injectable fluid pressurised by a pressurising member;

● at least one nozzle inlet port disposed in the tubular spray nozzle and through which the sprayable fluid is introduced into the nozzle;

● at least one receiver cylinder fixed directly or indirectly relative to an end of the tubular spray nozzle;

● at least one receiver piston fixed relative to the valve stem and housed in the receiver cylinder, the piston being movable in longitudinal translation in the cylinder and having an axial face on the side of the injectable fluid communicating with the internal volume of the tubular injection nozzle and an axial face on the side of the hydraulic fluid forming with the receiver cylinder a receiver chamber of variable volume filled with hydraulic fluid;

● connected to the receiver chamber and enabling the receiver piston to be actuated by the hydraulic fluid via an active hydraulic conduit.

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

The hydraulic injection system with cam according to the invention comprises a permeable guide member which is fixed directly or indirectly relative to the injection valve and/or the tubular injection nozzle, said member keeping the injection valve substantially centered in the tubular injection nozzle.

The hydraulic injection system with cam according to the invention comprises a hydraulic fluid supply consisting of an injection cam having at least one cam profile which is held in direct or indirect contact with an active axial face provided by an emitter piston housed in an emitter cylinder, the piston having an axial hydraulic fluid emitting face opposite the active axial face, the emitting face forming an emitting chamber with the emitter cylinder, the cam profile being able to move the emitter piston in the emitter cylinder in longitudinal translation when the injection cam is rotated by a drive source.

The hydraulic injection system with cam according to the present invention comprises an active hydraulic conduit connecting the emitter chamber to the receiver chamber, the conduit, the emitter chamber and the receiver chamber being filled with hydraulic fluid.

The hydraulic injection cam system according to the invention comprises a cam profile comprising at least one angular lifting sector which moves the emitter piston when the sector is in contact with the active axial face and when the injection cam rotates, and at least one angular retention sector which is circular and centered on the axis of rotation of the injection cam, which fixes the emitter piston when the sector is in contact with the active axial face and which does so despite the injection cam being rotated.

The hydraulic injection system with cam according to the invention comprises a cam profile which is held in contact with the active axial face by means of a rocker arm which is supported directly or indirectly on a cam housing in which the injection cam rotates.

The hydraulic injection system with a cam according to the invention comprises a rocker arm which is supported on the cam housing by means of a movable rocker point, the position of which rocker point between the cam contour and the active axial face can be varied by means of an injector lift actuator.

The hydraulic injection system with cam according to the present invention comprises a movable rocker point consisting of a movable pressure roller that can roll or slide on a displacement track provided in the cam housing, the pressure roller cooperating with a rocker arm track provided on the back of the rocker arm.

The hydraulic injection system with cam according to the present invention comprises a movable pressure roller which houses at each of its ends a directional pinion, the rotation of which is fixed, each of which cooperates with a directional rack fixed on the cam housing.

The hydraulic injection system with cam according to the present invention comprises a movable pressure roller housing a worm wheel cooperating with a worm whose axial position is fixed with respect to the cam housing, the worm being rotatably driven by the injector lift actuator.

The hydraulic injection system with cam according to the invention comprises a movable pressure roller provided with an internal thread in which the injector lift actuator can rotate a displacement screw fixed in position with respect to the cam housing but free to rotate about its longitudinal axis.

The hydraulic injection system with a cam according to the present invention includes an injection cam phaser interposed between the injection cam and the drive source.

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

The hydraulic injection system with cam according to the invention comprises a perforated diffuser, the inner wall of which is at least partially cylindrical and forms a small gap between itself and the outer peripheral surface of the funnel, so that the diffuser forms the permeable guide member.

The hydraulic injection system with cam according to the present invention comprises a charge pump apt to introduce hydraulic fluid, coming from a hydraulic fluid tank, to the active hydraulic conduit through a feed one-way valve.

The hydraulic injection system with cam according to the invention comprises at least one discharge orifice connected to a discharge conduit and opening into the receiver cylinder, the axial face of the jettable fluid side and the axial face of the hydraulic fluid side remaining axially positioned on either side of the orifice at all times, regardless of the position of the receiver piston.

The hydraulic injection system with cam according to the present invention includes a receiver piston having a drain groove in communication with the drain orifice.

The hydraulic injection cam system according to the present invention includes a receiver piston that is constituted by a first body that receives the axial surface on the ejectable fluid side and is fixed relative to the valve stem, and a second body that may or may not be fixed relative to the first body and that receives the axial surface on the hydraulic fluid side, an outer shoulder that forms a discharge groove provided on one, the other, or both of the bodies.

The hydraulic injection system with cam according to the invention comprises that the maximum displacement range of the movable rocker point between the cam profile and the active axial face is determined by at least one end-of-travel stop.

The hydraulic injection system with cam according to the present invention comprises a displacement track fixedly connected to the cam housing by at least one track-oriented ball joint.

The hydraulic injection system with cam according to the present invention comprises a receiver piston constituted by at least one first body that receives the axial face on the side of the jettable fluid and is fixed with respect to the valve stem, and by at least one second body that may or may not be fixed with respect to the first body and that receives the axial face on the side of the hydraulic fluid.

The hydraulic injection system with cam according to the present invention comprises a receiver piston comprising an external shoulder arranged on one, the other or both bodies, said shoulder forming a discharge groove communicating with at least one discharge orifice arranged within the receiver cylinder and connected to a discharge conduit.

The following description, together with the accompanying drawings, provided as a non-limiting example, will give a better understanding of the invention, its nature and the advantages it may provide:

fig. 1 is a schematic cross-sectional view of a hydraulic injection system with a cam according to the invention, which can be installed in the cylinder head of an internal combustion engine equipped with a valve ignition prechamber according to french patent application FR 1750264 and an ignition insert with an active prechamber according to french patent application 3060222.

Fig. 2 is a schematic cross-sectional view showing an angular lift and hold sector that a cam profile of a hydraulic injection system having a cam according to the present invention can accommodate.

Fig. 3 to 5 are schematic sectional views illustrating the operation of an injection cam and an emitter piston of a hydraulic injection system with a cam according to the present invention, the cam cooperating with a rocker arm whose lever arm can be varied depending on the position of a movable platen, the position being controlled by a step motor through a worm and a worm wheel.

Fig. 6 is a three-dimensional view of an injection cam of a hydraulic injection system with cam according to the invention and the main functional components shown in fig. 3 to 5 cooperating with the cam.

Fig. 7 is a three-dimensional view of the tubular spray nozzle of the hydraulic spray system with cam and the main components it houses or cooperates with, according to the invention.

Fig. 8 is a three-dimensional cross-sectional view of a tubular spray nozzle of a hydraulic spray system with a cam and the main components that it houses or cooperates with, according to the present invention.

Fig. 9 is a three-dimensional view of an injection valve of a hydraulic injection system with a cam according to the present invention, which is equipped with a receiver piston and a receiver piston return spring.

Fig. 10 is a three-dimensional view of a perforated diffuser according to the present invention that can be arranged to end in the injection nozzles of a hydraulic injection system with cams.

Fig. 11 is a schematic cross-sectional view of a tubular injection nozzle of a hydraulic injection system with cam according to the invention and its main components housed or cooperating therewith, which can be installed in the head of an internal combustion engine equipped with a valve ignition prechamber according to french patent application FR 1750264 and an ignition insert with an active prechamber according to french patent application 3060222.

Fig. 12 is a three-dimensional perspective view of an injection cam of a hydraulic injection system having a cam, the movable pressure roller of which is provided with an internal thread, in which the injector lift actuator can rotate the displacement screw, according to the present invention.

Detailed Description

Fig. 1 through 12 illustrate various details of a hydraulic jetting system 100 with a cam, its components, variations, and accessories, in accordance with the present invention.

As shown in fig. 1 and 7-11, a cam-equipped hydraulic injection system 100 includes at least one injection valve 50 including a valve stem 51 and terminating in an enlarged end portion or funnel 52 forming a valve sealing surface 53.

As can be seen in fig. 1 and 7 to 11, the valve 50 is wholly or partially housed in a tubular spray nozzle 54 which terminates in a spray valve seat 55 on which a valve sealing surface 53 can be sealingly seated, with a clearance formed between the valve stem 51 and the inner surface of the tubular spray nozzle 54 to allow the flow of a sprayable fluid 58 pressurized by the pressurizing member 10. It is further noted that, according to a particular method of manufacturing a hydraulic injection system with a cam according to the present invention, the valve sealing surface 53 may be frusto-spherical while the injection valve seat 55 is conical.

In fig. 8, 9, 10 and 11, it can be seen that a hydraulic injection system 100 with a cam provides a permeable guide member 56 that is fixed directly or indirectly relative to injection valve 50 and/or tubular injection nozzle 54. Said member 56 keeps the injection valve 50 substantially centred in the tubular injection nozzle 54, irrespective of the axial position of said valve 50 with respect to said nozzle 54.

In fig. 8, 9, 10 and 11, it should be noted that the permeable guide member 56 may comprise at least one gas channel 57 that allows the jettable fluid 58 to flow between the injection valve 50 and the tubular injection nozzle 54.

In fig. 7, 8 and 11, it is noted that the hydraulic injection system 100 with cam comprises a nozzle inlet port 59 which is arranged in the tubular injection nozzle 54 and through which the injectable fluid 58 is introduced into said nozzle 54 after being conveyed through the injectable fluid supply conduit 66 connecting the pressurizing member 10 to said port 59.

It should be noted that the connection between the sprayable fluid supply conduit 66 and the nozzle inlet port 59 may be achieved by welding, crimping, by means of a "butt joint" fitting known per se, or by using any type of connecting block.

In addition, the ejectable fluid supply conduit 66 may be equipped with a heating means for heating by electrical resistance, external circulation of a heat transfer fluid such as water or oil, or by any other means. The heating member makes it possible to favorably accelerate the temperature increase of the ejectable fluid supply conduit 66 during the start-up of the hydraulic injection system 100 with cam according to the present invention in a low-temperature environment.

These or similar components may also be applied to the hydraulic conduit 78 and/or the tubular spray nozzle 54.

As shown in fig. 8 and 11, the hydraulic injection system with cam 100 comprises at least one receiver cylinder 61, fixed directly or indirectly with respect to the end of the tubular injection nozzle 54 opposite to the end of the nozzle 54 receiving the injection valve seat 55, said receiver cylinder cover 61 being positioned in extension of said nozzle 54.

Furthermore, fig. 1, 8, 9 and 11 show that the hydraulic injection system 100 with cam comprises at least one receiver piston 62 fixed with respect to the valve stem 51 and housed in a receiver cylinder 61, said piston 62 being movable in longitudinal translation in said cylinder 61 and having an axial face 63 on the side of the injectable fluid communicating with the internal volume of the tubular injection nozzle 54 and an axial face 64 on the side of the hydraulic fluid forming a receiver chamber 71 of variable volume with the receiver cylinder 61 and with the receiver cylinder cap 74 terminating at said cylinder 61.

It should be noted that the receiver piston 62 may be made of one or more pieces and may receive any type of seal, in particular a composite seal having a low coefficient of friction and high wear resistance. This particular configuration may also be applied to the emitter piston 69.

In fig. 1 to 6 and 12, it can be seen that a hydraulic injection system 100 with a cam comprises a hydraulic fluid supply 65 consisting of at least one injection cam 67 having at least one cam profile 68 which is held in contact, directly or indirectly, with an active axial face 75 of an emitter piston 69 accommodated in an emitter cylinder 70.

In particular, in fig. 3 to 6 and 12, it should be noted that the piston 69 has an axial hydraulic fluid emission surface 76 opposite the active axial surface 75, which forms an emission chamber 72 with the emission cylinder 70 and an emission cylinder cover 77 ending in said cylinder 70, whereas the cam profile 68 can move the emission piston 69 in a longitudinal translational manner in the emission cylinder 70 when the injection cam 67 is rotated by the drive source 73.

The drive source 73 may be an electric motor, a hydraulic motor, a crankshaft of the combustion engine 2 or any other drive source 73 to which the injection cam 67 is connected by any type of transmission, whether it be a shaft, a belt or a toothed belt, a chain or a sprocket.

It should be noted that if the injection cam 67 is driven by the crankshaft of the internal combustion engine 2, it may be fixed with respect to the camshaft of said engine 2, or placed at the end of the central shaft of the air compressor forming the pressing member 10, or house a dedicated pulley driven by the timing belt of said engine 2.

In particular in fig. 1, it can be seen that the hydraulic injection system 100 with cam comprises at least one active hydraulic conduit 78 connecting the emitter chamber 72 to the receiver chamber 71, said conduit 78, emitter chamber 72 and receiver chamber 71 being filled with hydraulic fluid 60.

Fig. 8, 9 and 11 illustrate that a receiver piston return spring 79 may be provided which tends to move the receiver piston 62 closer to the receiver cylinder head 74, thereby tending to maintain the valve seal seat 53 in contact with the injection valve seat 55.

The spring 79 may be housed, for example, in the receiver cylinder 61 or in the tubular spray nozzle 54 and is helical, or formed by a stack of spring washers or of any other type known to the skilled person. It should be noted that a similar return spring may tend to move the launcher piston 69 closer to the launcher cylinder head 77.

As clearly shown in fig. 2, the cam profile 68 comprises at least one angular lifting sector 15, which moves the launcher piston 69 when said sector 15 is in contact with the axial action face 75 and the injection cam 67 rotates, and at least one angular retention sector 16, which is circular and centred on the axis of rotation of said injection cam 67, which fixes the launcher piston 69 when said sector 16 is in contact with the action axial face 75 and which does so despite the injection cam 67 being rotated.

It should be noted that the difference between the radius of the cam profile 68 at the retention angular sector 16 and the maximum radius at the lifting angular sector 15 determines the lift L generated by the injection cam 67 at the level of the cam profile 68. A higher or lower lift of the injection valve 50 corresponds to the L value, taking into account possible mechanical and/or hydraulic lever arms.

In the variant embodiment of the hydraulic injection system 100 according to the invention with cam shown in fig. 1, 3 to 6 and 12, the cam profile 68 can be held in contact with the active axial face 75 by means of a rocker arm 80, which is directly or indirectly supported on a cam housing 81 in which the injection cam 67 rotates.

In fig. 1, 3 to 6 and 12, it should be noted that advantageously the rocker arm 80 can be kept in contact with the cam profile 68 by means of a compression roller 86, known per se, which limits the friction losses at the interface between said rocker arm 80 and said cam profile 68.

In fig. 1, 3 to 6 and 12, it is further noted that according to a particular embodiment of the hydraulic injection system 100 with cam according to the present invention, the rocker arm 80 can be kept in contact with the cam profile 68 or the active axial face 75 by means of the rocker arm return spring 14.

In addition, the rocker arm 80 may cooperate with a guide member, not shown, arranged in the cam housing 81 in such a way that said rocker arm 80 cannot rotate about an axis perpendicular to its operative rocking axis.

In fig. 1, 3 to 6 and 12, it can be seen that the rocker arm 80 can be supported on the cam housing 81 by means of a movable rocker point 82, the position of which between the cam contour 68 and the active axial face 75 can be changed by means of an injector lift actuator 83.

As can be easily inferred from fig. 1, 3 to 6 and 12, for the same cam profile 68, the position of the movable rocker point 82 determines the displacement of the active axial face 75 and thus the lift height of the injection valve 50 relative to the injection valve seat 55 with which it cooperates.

Thus, if tubular injection nozzle 54 opens to a certain volume at a constant pressure for a given rotational speed of injection cam 67 and a given pressure of injectable fluid 58 in injectable fluid supply conduit 66, the greater the lift height of injection valve 50, the greater the amount of injectable fluid 58 that is discharged from tubular injection nozzle 54 through the passage formed between valve sealing surface 53 and injection valve seat 55.

Fig. 1, 3 to 6 and 12 show that the movable rocker point 82 can advantageously be formed by a movable pressure roller 84 which can roll or slide on a displacement track 85 formed in the cam housing 81, said pressure roller 84 cooperating with a rocker arm track 87 on the back of the rocker arm 80.

As can be seen in fig. 1, 3 to 6 and 12, the rocker arm 80 can advantageously be articulated about a ball joint 88 fixed relative to the active axial face 75. As a refinement, the bearing rollers 86 may have an outer barrel shape. According to this particular configuration, the displacement rail 85 and the inclined rail 87 can be completely flat, and the movable roller 84 is completely cylindrical. This non-limiting configuration makes it possible to avoid any of the above-listed ultra-static relationships between the

various features

84, 85, 86, 87, while avoiding the need to create a cam profile 68 in which the outer axial surface is curved.

Fig. 6 clearly shows that the movable pressure roller 84 houses, at each of its ends, an orientation pinion 89, the rotation of said pinions 89 being fixed, while each of said pinions 89 cooperates with an orientation rack 90 fixed with respect to the cam housing 81.

This particular configuration makes it possible for the movable pressure roller 84 to remain perpendicular to the displacement track 85 with which it cooperates, and this independently of the position of said roller 84 with respect to said track 85.

Fig. 6 also clearly shows that the movable pressure 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, the worm 92 may be rotated by an injector lift actuator 83, as shown in fig. 1 and 3 to 6, which may be an electric stepper motor 93 with or without any type of gearbox and controlled by an ECU.

It should be noted that the electric stepper motor 93, as well as any injector lift actuators 83, may be connected to the worm 92 directly or through a belt, chain, sprocket, or any other type known to those skilled in the art.

Therefore, when the injector lift actuator 83 rotates the worm 92, the movable pressure roller 84 moves relative to the displacement rail 85 in cooperation therewith, thereby displacing the position of the movable rocker point 82 relative to the cam housing 81. This makes it possible to adjust the amount of the jettable fluid 58 discharged from the tubular jet nozzle 54.

It should be noted that one and the same movable pressure roller 84 may cooperate with multiple rocker arms 80 to change the lever arm simultaneously, or one and the same electric stepper motor 93 may move several movable pressure rollers 84.

Alternatively, as shown in fig. 12, the movable pressure roller 84 may be provided with a threaded hole in which the injector lift actuator 83 may rotate the displacement screw 17, which is fixed in position relative to the cam housing 81 but is free to rotate about its longitudinal axis, thereby sliding the movable pressure roller 84 on the displacement rail 85.

In fig. 1, it has been shown that an injection cam phaser 96 may be interposed between injection cam 67 and drive source 73, for example, when source 73 is comprised of the crankshaft of internal combustion engine 2, phaser 96 may enable injection cam 67 to be angularly advanced or retarded relative to drive source 73 to impart movement to firing piston 69.

It should be noted that the principles of the injection cam phaser 96 may be similar to those of a hydraulic or electric camshaft phaser of an automotive internal combustion engine.

In fig. 10, it has been shown that the tubular spray nozzle 54 terminating at the spray valve seat 55 may be capped with a perforated diffuser 94 that forces the sprayable fluid 58 discharged from the tubular spray nozzle 54 through the passage formed between the valve sealing surface 53 and the spray valve seat 55 through one or more spray orifices 95 in order to generate a spray of the sprayable fluid 58.

According to this variant of the hydraulic injection system with cam 100 of the invention, at least a portion of the inner wall of the perforated diffuser 94 is cylindrical and forms a small clearance between itself and the outer peripheral surface of the funnel 52, so that said diffuser 94 forms the permeable guide member 56.

Finally, fig. 1 shows that a charging pump 7 may be provided, which tends to introduce the hydraulic fluid 60, said hydraulic fluid 60 coming from the hydraulic fluid tank 11, through the charging check valve 8 into the active hydraulic conduit 78.

It should be noted that according to a particular embodiment of the hydraulic injection system 100 with cam according to the present invention, the charge pump 7 may be constituted by the lubrication pump of the internal combustion engine 2, while the hydraulic oil tank 11 is constituted by the oil pan of said engine 2. It should further be noted that the active hydraulic conduit 78 may comprise a pressure limiter and a purging device known per se.

As shown in fig. 11, it can be seen that a hydraulic injection system 100 with a cam according to the present invention may house at least one discharge orifice 97 connected to a discharge conduit 99 and leading to the receiver cylinder 61. It will be appreciated that in this case, regardless of the position of the receiver piston 62, the jettable fluid side axial face 63 and the hydraulic fluid side axial face 64 remain axially positioned on either side of the orifice 97 at all times.

According to this particular configuration, the receiver piston 62 has a discharge groove 98 communicating with the discharge orifice 97, said groove 98 collecting, on the one hand, the ejectable fluid 58 leaking from the ejectable fluid side axial face 63 between the receiver piston 62 and the receiver cylinder 61, and, on the other hand, the hydraulic fluid 60 and/or air leaking from the hydraulic fluid side axial face 64 between said piston 62 and said cylinder 61, so that said ejectable fluid 58, said hydraulic fluid 60 and/or said air can be discharged through the discharge conduit 99.

It should be noted that the drain groove 98, drain port 97 and drain conduit 99 thereby permanently remove any air in the active hydraulic conduit 78 that is detrimental to the normal operation of the hydraulic injection system 100 with cams in accordance with the present invention.

In fig. 11, it can be seen that the receiver piston 62 may be comprised of an outer shoulder 20 forming a drain groove 98 provided on one, the other or both of the bodies, a first body that receives the jettable fluid side axial face 63 and is fixed relative to the valve stem 51, and a second body that may or may not be fixed relative to the first body and receives the hydraulic fluid side axial face 64.

It is noted in fig. 12 that the maximum displacement range of the movable rocker point 82 between the cam profile 68 and the active axial face 75 can be advantageously determined by at least one end-of-stroke stop 19, which constitutes in particular a geometric reference position that the injector lift actuator 83 can use to readjust the position of the movable rocker point 82 and to adjust the correct amount of the injectable fluid 58 that is ejected from the tubular injection nozzle 54 through the passage formed between the valve sealing surface 53 and the injection valve seat 55.

Fig. 12 also illustrates that the displacement track 85 may be fixed relative to the cam housing 81 by at least one track-oriented ball joint 18 that allows the track 85 to conform to the orientation of the rocker arm 80 imposed by the geometric environment of the rocker arm 80.

As shown in fig. 12, according to a variant embodiment of the hydraulic injection system with cam 100 of the present invention, the axial position of the orbital ball joint 18 in the cam housing 81 can be adjusted by adjusting the screw 21.

The invention has the following operation:

the operation of the hydraulic injection system 100 with cam according to the present invention is easily understood from fig. 1 to 12.

To elaborate the operation of the system 100, a valve ignition prechamber is applied here, which is the subject of french patent application FR 1750264, which prechamber on the one hand houses a valve magnetic return device as the subject of french patent application 1858111 and on the other hand an active prechamber ignition insert as the subject of french patent application 1904961.

Fig. 1 and 11 show a hydraulic injection system 100 with cam, equipped according to this non-limiting example with an internal combustion engine 2, in particular comprising a cylinder 4 topped by a head 3, said cylinder 4 and said head 3, said head forming, together with a piston 31, a combustion chamber 5.

In fig. 1 and 11, a valve ignition prechamber 1 is shown, which is arranged in an ignition insert with an active prechamber 6 accommodated in the cylinder head 3. Fig. 1 and 11 also show that tubular injection nozzle 54 and injection valve 50 open into valve ignition prechamber 1 for introducing an injectable fluid 58, which according to this example consists of a highly combustible AF mixture of air and gasoline.

The AF mixture forms a pilot charge 9 intended to be ignited by a spark plug 12 that enters the flap ignition prechamber 1. Once ignited, the pilot charge 9 will be injected through the gas injection orifices 24 into the combustion chamber 5 in the form of a high temperature gas flame. The flame is intended to ignite a main charge 30 contained in the combustion chamber 5.

In fig. 1 and 11, the valve ignition prechamber 1 and the combustion chamber 5 are separated by a valve member 13 which is returned to its seat by a permanent magnet 49 which is part of a valve magnetic return device 42 as described in french patent application No. 1858111, which belongs to the applicant. Said valve member 13 allows the gas contained in the valve prechamber 1 to flow into the combustion chamber 5, but prevents the gas contained in said combustion chamber 5 from entering the valve ignition prechamber 1.

When closed, the valve member 13 brings the valve ignition prechamber 1 into a closed volume, the pressure and temperature of which are lower than the pressure and temperature in the combustion chamber 5. This thereby prevents any risk of auto-ignition of the pilot charge 9 in the prechamber 1.

With valve 13 closed, tubular injection nozzle 54 can inject the required highly combustible pilot charge 9 into valve ignition prechamber 1 without any risk of pilot charge 9 mixing with main charge 30, which is difficult to ignite and must be placed at higher pressures and temperatures to allow and promote its ignition.

It should be noted that the particular configuration of the head 3 and of the active prechamber ignition insert 6 shown in fig. 1 and 11 requires a tubular injection nozzle 54 having a large length. The latter is incompatible with the technical and manufacturing limitations of compact and economical injectors commonly used in motor vehicles. However, if the hydraulic injection system 100 having a cam according to the present invention is used, the large length does not cause any particular problem.

It is assumed here that the pressure of the ejectable fluid 58 supplied by the pressing member 10 to the tubular ejection nozzle 54 is fifty bars. This pressure must not be exceeded because the injectable fluid 58 consists of an AF gaseous mixture of air and gasoline. In fact, the jettable fluid 58 should be maintained at a temperature of one hundred degrees Celsius. This temperature is applied by water circulating in the cooling water chamber 41 of the cylinder head 3 of the internal combustion engine 2. However, if the pressure of the injectable fluid 58 at this temperature exceeds fifty bar, some gasoline in the AF gaseous mixture will inevitably condense.

It should be remembered that during the compression stroke of the internal combustion engine 2, the tubular injection nozzle 54 injects an injectable fluid 58 into the valve ignition prechamber 1 to form the pilot charge 9, so as to be careful to ensure that the pressure in the prechamber 1 is always lower than the pressure in the combustion chamber 5.

This constraint results in the injection duration of the pilot charge 9 being limited to, for example, forty degrees of the crankshaft of the internal combustion engine 2.

The above length, temperature and pressure constraints make the hydraulic injection system 100 with cams according to the present invention particularly interesting. In fact, system 100 can produce a long and compact tubular injection nozzle 54 capable of injecting the necessary pilot charge 9 into the valve ignition prechamber 1 at a crankshaft degree of less than forty degrees, although the upstream pressure of the injectable fluid 58 is limited to fifty bar due to its temperature being limited to one hundred degrees celsius.

To achieve this result, it can be seen in fig. 8 and 11 that the cross section of the jettable fluid-side axial face 63 of the receiver piston 62 exposed to the pressure of the jettable fluid 58 is designed to be larger than the cross section of the funnel 52 of the injection valve 50 exposed to said pressure when said valve 50 rests on the injection valve seat 55 cooperating therewith.

Thus, with the additional action of the receiver piston return spring 79, the pressure in the tubular injection nozzle 54 tends to press the valve sealing surface 53 against the injection valve seat 55 and keep the injection valve 50 closed. This high return force, generated by the pressure of the jettable fluid 58, makes it possible to avoid the need for a heavy and bulky high force receiver piston return spring 79.

In connection with fig. 1, it is assumed that the charge pump 7, which supplies hydraulic fluid 60 to the working hydraulic conduit 78 through the charge check valve 8, is a lubrication pump of the internal combustion engine 2, while the hydraulic fluid tank 11 consists of the oil pan of the internal combustion engine 2.

In this case, the force of the receiver piston return spring 79 is advantageously set to be significantly greater than the force of the pressure generated by the lubrication pump of the internal combustion engine 2 on the receiver piston 62.

As can also be seen from fig. 1 and 11, in this case the injectable fluid supply conduit 66 is arranged directly in the cylinder head housing 3, while the injection cam 67 is driven by the camshaft of the internal combustion engine 2.

As shown in fig. 1, 3 to 6 and 12, it is assumed here that the cam profile 68 of the injection cam 67 is held in contact with the active axial face 75 of the launcher piston 69 by means of a rocker arm 80, the latter being held in contact with the cam profile 68 by means of a pressure roller 86.

As shown in fig. 1, 3 to 6, and 12, it is also assumed that the rocker arm 80 is supported on the cam housing 81 by a movable pressure roller 84 that can roll or slide on a displacement rail 85 provided in the cam housing 81, the pressure roller 84 cooperating with an inclined rail 87 provided on the back surface of the rocker arm 80.

In fig. 1, 3 to 6 and 12, it can be seen that the displacement track 85 is advantageously completely perpendicular to the axis of the firing piston 69. In addition, in fig. 1, 3, 5, 6 and 12, it can be seen that when the pressing roller 86 is in contact with the angle maintaining sector 16 and the firing piston 69 pushes the rocker arm 80 through its acting axial face 75 to press the rocker arm 80 onto the displacement track 85 by the movable pressing roller 84, the inclined track 87 of the rocker arm 80 is kept parallel to the displacement track 85 regardless of the position of the movable pressing roller 84.

In this respect it should be noted that it is possible to provide screw or cam adjustment means or any other adjustment means which make it possible to adjust the perpendicularity of the displacement track 85 with respect to the axis of the launching piston 69 and/or the distance of the displacement track 85 from the injection cam 67 along an axis parallel to the axis of the launching piston 69. As can be seen from fig. 12, the adjusting device can be designed as an adjusting screw 21.

To avoid any inaccuracies in the above-described arrangement, it is advantageous to allow a small amount of hydraulic fluid 60 to escape directly or indirectly from the apply hydraulic conduit 78 during each opening cycle of the injection valve 50. This may be done, for example, by an emitter piston 69 that is not completely sealed, or by a very small cross-section nozzle placed at any point in the circuit connecting the emitter chamber 72 and the receiver chamber 71 that allows some hydraulic fluid 60 to escape and return to the hydraulic fluid tank 11.

In particular in fig. 6, it can be seen that the movable pressure roller 84 houses, at each of its ends, an orientation pinion 89, the rotation of said pinions 89 being fixed, while each of said pinions 89 cooperates with an orientation rack 90 integral with the cam housing 81.

It is also noted that the movable pressure roller 84 houses a worm wheel 91, which cooperates with a worm 92, the axial position of which is fixed with respect to the cam housing 81, said worm 92 being rotatably driven by an injector lift actuator 83, which, according to a non-limiting example, consists of an electric stepper motor 93.

It should be noted that advantageously, the pitch diameter of the orienting pinion 89 is the same as that of the worm gear 91, without excluding the possibility of their difference.

Therefore, when the electric stepping motor 93 rotates the worm gear 92, the movable pressure roller 84 moves relative to the displacement rail 85 cooperating therewith, so that the position of the movable rocker point 82 moves relative to the cam housing 81.

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

When the internal combustion engine 2 is running, the injection valve 50 is held closed, for example, initially by the receiver piston 62 due to the pressure in the nozzle pipe and to a lesser extent by the receiver piston return spring 79. This is illustrated in fig. 1 and 11 and is caused, for example, by any of the angular positions of the injection cam 67 shown in fig. 1, 3, 5 or 6.

As shown in fig. 4, with the internal combustion engine 2 still running, the cam profile 68 pushes the rocker arm 80. The rocker arm 80 tilts and moves the launcher piston 69, which in turn forces the hydraulic fluid 60 to flow from the launcher chamber 72 to the receiver chamber 71. This displaces the receiver piston 62 and moves the valve sealing surface 53 away from the injection valve seat 55, resulting in a transfer of the injectable fluid 58 from the tubular injection nozzle 54 to the valve ignition prechamber 1.

Fig. 5 shows that, to adjust the lift height of the injection valve 50, the stepper motor 93 can move the movable pressure roller 84 closer to or away from the launcher piston 69 via the worm 92 in order to change the lever arm of the rocker arm 80 and thereby change the displacement ratio between the launcher piston 69 and the receiver piston 62.

In fact, the displacement ratio between the displacement of the launcher piston 69 and the effective lift of the injection valve 50 depends on the lever arm of the rocker arm 80, and also on the compressibility of the hydraulic fluid 60 in the launcher chamber 72, the receiver chamber 71 and the working hydraulic conduit 78.

The force applied by the rocker arm 80 to the active axial face 75 of the launcher piston 69 depends in particular on the pressure of the ejectable fluid 58 in the tubular ejection nozzle 54 and the ratio between the cross section exposed to the pressure of the ejectable fluid 58 via the axial face 63 on the ejectable fluid side and the cross section exposed to this pressure via the funnel 52.

To a lesser extent, the force also depends on the force generated by the receiver piston return spring 79. In addition to this, there are also the inertia of the various moving elements and their energy losses through mutual friction, and in particular the pressure losses generated by the hydraulic fluid 60 flowing in the working hydraulic conduit 78.

However, for each operating point of the internal combustion engine 2 there is a position of the electric stepping motor 93 which allows a pilot charge 9 which is most favorable for the thermodynamic efficiency of the internal combustion engine 2 to be introduced into the valve ignition prechamber 1. The existing relationship between the position of the stepper motor 93 and the pilot charge 9 can be found on the test bench for each operating point of the internal combustion engine 2, thereby avoiding the development of a predictive numerical model that would not be useful in this case.

Therefore, the position of the electric stepping motor 93 is designed to vary as needed, specifically, as a function of the speed, load, and dilution of the main load 30 of the internal combustion engine 2. Regarding the degree of dilution, it should be noted that the more diluted the main charge 30 is with fresh air or recirculated exhaust gas, the less easily it ignites, and the greater the energy contained in the pilot charge 9 must be in relation to the energy contained in the main charge 30.

Furthermore, the faster the internal combustion engine 2 is operated, the higher the lift of the injection valve 50 must be in order to introduce the same amount of pilot charge 9. In fact, the faster the engine 2 runs, the shorter the absolute duration of the injection valve lift 50, for the same position of the movable pressure roller 84, in order to inject the same mass of injectable fluid 58 into the valve ignition prechamber 1. Therefore, the reduction in injection duration must be compensated for by increasing the flow cross section existing between the valve sealing surface 53 and the injection valve seat 55, and thus by increasing the injection valve lift 50.

It can also be seen that, since the internal combustion engine 2 operates very quickly, the influence of the compressibility of the hydraulic fluid 60 is more pronounced, since the acceleration of the element to be displaced increases and thus leads to an increase in the peak pressure reached by the fluid 60. This effect will also be compensated for by the proper position of the movable pressure roller 84 of the electric stepping motor 93.

A map of the ideal position of the electric stepper motor 93, taking into account the operating conditions of the internal combustion engine 2, is stored in the memory of the computer 48, with or without correction by an algorithm taking into account contextual operating parameters, such as temperature or ageing.

It should be noted that when the internal combustion engine 2 is started at a very low temperature, e.g., thirty degrees celsius below zero, the pressure of the injectable fluid 58 in the injectable fluid supply conduit 66 and the tubular injection nozzle 54 must be drastically reduced, e.g., five bar instead of fifty bar.

This lower pressure ensures that the gasoline in the AF gasoline/air mixture does not condense and ensures that the nominal concentration of the AF gasoline/air mixture is maintained. As a result, during the warm-up phase of the internal combustion engine 2, the maximum load of the engine is limited to an average effective pressure of about ten bar, which makes it possible for any motor vehicle equipped with an engine to be used immediately.

After a few seconds, the rapid heating up of the pressurizing member 10, the injectable fluid supply conduit 66 and the tubular injection nozzle 54 allows to resume normal operation, the pressure of the injectable fluid 58 in the tubular injection nozzle 54 reaching about fifty bars.

The above-described operation example of the hydraulic injection system 100 with cam according to the present invention is by no means limitative. In fact, the system can allow the injection of natural gas, heavy fuel oil, diesel oil or petrol, directly or indirectly, into any internal combustion engine 2, whatever its principle.

In general, the hydraulic injection system 100 with cam according to the present invention is able to allow any gas and/or any liquid to be injected into any machine requiring such injection, whether or not controlled by the injector lift actuator 83.

Moreover, the possibility of a hydraulic injection system 100 with cam according to the present invention is not limited to the above-mentioned applications, moreover it must be understood that the foregoing description is given by way of example only and that it does not in any way limit the field of invention, the details of execution of which are described by replacing any other equivalent without departing from this field.

Claims

1. A hydraulic injection system (100) having a cam, characterized in that the hydraulic injection system comprises:

● at least one injection valve (50) comprising a valve stem (51) and terminating in an enlarged portion or funnel (52) forming a valve sealing seat (53), the valve (50) being wholly or partially housed in a tubular injection nozzle (54) terminating in an injection valve seat (55) on which the valve sealing surface (53) can sealingly rest with a clearance formed between the valve stem (51) and an inner surface of the tubular injection nozzle (54) to allow the flow of an injectable fluid (58) pressurized by a pressurizing member (10);

● at least one nozzle inlet port (59) disposed in the tubular spray nozzle (54) and through which the sprayable fluid (58) is introduced into the nozzle (54);

● at least one receiver cylinder (61) fixed directly or indirectly relative to an end of the tubular spray nozzle (54);

● at least one receiver piston (62) fixed relative to the valve stem (51) and housed in the receiver cylinder (61), the piston (62) being movable in longitudinal translation in the cylinder (61) and having an axial face (63) on the jettable fluid side communicating with the internal volume of the tubular injection nozzle (54) and an axial face (64) on the hydraulic fluid side forming a receiver chamber (71) of variable volume filled with hydraulic fluid (60) with the receiver cylinder (61);

● connected to the receiver chamber (71) and enabling actuation of the receiver piston (62) by the hydraulic fluid (60) via an active hydraulic conduit (78).

2. The hydraulic injection system with cam of claim 1, characterized by a receiver piston return spring (79) tending to move the receiver piston (62) closer to a receiver cylinder head (74).

3. Hydraulic injection system with cam according to claim 1, characterized in that a permeable guiding member (56) is fixed directly or indirectly with respect to the injection valve (50) and/or the tubular injection nozzle (54), said member (56) keeping the injection valve (50) substantially centered in the tubular injection nozzle (54).

4. Hydraulic injection system with cam according to claim 1, characterized in that the hydraulic fluid supply means (65) consist of an injection cam (67) having at least one cam profile (68) directly or indirectly in contact with an active axial face (75) of an emitter piston (69) housed in an emitter cylinder (70), the piston (69) having an axial hydraulic fluid emitting face (76) opposite the active axial face (75) forming an emitting chamber (72) with the emitter cylinder (70), the cam profile (68) being able to move the emitter piston (69) in longitudinal translation in the emitter cylinder (70) when the injection cam (67) is rotated by a drive source (73).

5. The hydraulic jetting system with cam of claim 4, characterized in that the active hydraulic conduit (78) connects the emitter chamber (72) to the receiver chamber (71), the conduit (78), the emitter chamber (72) and the receiver chamber (71) being filled with hydraulic fluid (60).

6. Hydraulic injection system with cam according to claim 4, characterized in that the cam profile (68) comprises at least one angular lifting sector (15) which moves the launcher piston (69) when the sector (15) is in contact with the axial active face (75) and when the injection cam (67) rotates, and at least one angular retention sector (16) which is circular and centered on the axis of rotation of the injection cam (67), which fixes the launcher piston (69) when the sector (16) is in contact with the active axial face (75) and does so despite the injection cam (67) being rotated.

7. Hydraulic injection system with cam according to claim 4, characterized in that the cam profile (68) is held in contact with the active axial face (75) by means of a rocker arm (80) which is supported directly or indirectly on a cam housing (81) in which the injection cam (67) rotates.

8. Hydraulic injection system with cam according to claim 7, characterized in that the rocker arm (80) is supported on the cam housing (81) by a movable rocker point (82), the position of which between the cam profile (68) and the axial active face (75) can be changed by an injector lift actuator (83).

9. The hydraulic jetting system with cam of claim 8, characterized in that the movable rocker point (82) consists of a movable roller (84) that can roll or slide on a displacement track (85) provided in the cam housing (81), the roller (84) cooperating with a rocker track (87) provided on the back of the rocker arm (80).

10. Hydraulic jetting system with cam, according to claim 9, characterised in that the movable pressure roller (84) at each of its ends houses an orientation pinion (89), the rotation of the pinions (89) being fixed, while each pinion (89) cooperates with an orientation rack (90) fixed on the cam housing (81).

11. Hydraulic injection system with cam according to claim 10, characterized in that the movable pressure roller (84) houses a worm wheel (91) cooperating with a worm screw (92) whose axial position is fixed with respect to the cam housing (81), the worm screw (92) being rotatably driven by the injector lift actuator (83).

12. Hydraulic injection system with cam according to claim 10, characterized in that the movable pressure roller (84) is provided with an internal thread in which the injector lift actuator (83) is able to rotate a displacement screw (17) which is fixed in position with respect to the cam housing (81) but is free to rotate about its longitudinal axis.

13. The hydraulic injection system with cam according to claim 4, characterized in that an injection cam phaser (96) is interposed between the injection cam (67) and the drive source (73).

14. Hydraulic injection system with cam according to claim 1, characterized in that the end of the tubular injection nozzle (54) ending in the injection valve seat (55) is covered by a perforated diffuser (94).

15. The hydraulic jetting system with cam of claim 14, characterized in that at least a portion of an inner wall of the perforated diffuser (94) is cylindrical and forms a small gap between itself and an outer peripheral surface of the funnel (52) such that the diffuser (94) forms the permeable guide member (56).

16. Hydraulic injection system with cam according to claim 1, characterised in that a charge pump (7) tends to introduce hydraulic fluid (60) into the active hydraulic conduit (78) through a charge one-way valve (8), the hydraulic fluid (60) coming from a hydraulic fluid tank (11).

17. The hydraulic injection cam system according to claim 1, characterized in that at least one discharge orifice (97) connected to a discharge conduit (99) opens into the receiver cylinder (61), the axial face (63) on the ejectable fluid side and the axial face (64) on the hydraulic fluid side remaining axially positioned on either side of the orifice (97) at all times, regardless of the position of the receiver piston (62).

18. The hydraulic jetting system with cam of claim 17, characterized in that the receiver piston (62) has a drain groove (98) in communication with the drain orifice (97).

19. The hydraulic injection cam system of claim 18, characterized in that the receiver piston (62) is constituted by a first body that receives the axial face (63) on the ejectable fluid side and is fixed relative to the valve stem (51), and a second body that may or may not be fixed relative to the first body and that receives the axial face (64) on the hydraulic fluid side, an outer shoulder (20) provided on one, the other, or both of the bodies that forms the discharge groove (98).

20. Hydraulic injection system with cam according to claim 8, characterised in that the maximum displacement range of the movable rocker point (82) between the cam profile (68) and the active axial face (75) is determined by at least one end-of-stroke stop (19).

21. Hydraulic injection system with cam according to claim 9, characterized in that the displacement track (85) is fixedly connected to the cam housing (81) by means of at least one track-oriented ball joint (18).

22. The hydraulic injection cam system according to claim 1, characterized in that the receiver piston (62) is constituted by at least one first body that receives the axial face (63) on the ejectable fluid side and is fixed relative to the valve stem (51), and by at least one second body that may or may not be fixed relative to the first body and that receives the axial face (64) on the hydraulic fluid side.

23. The hydraulic injection cam system of claim 22, characterized in that the receiver piston (62) includes an external shoulder (20) disposed on one body, the other body, or both bodies, the shoulder (20) forming a drain groove (98) in communication with at least one drain orifice (97) disposed within the receiver cylinder (61) and connected to a drain conduit (99).