Ignition pre-chamber with oriented valve

Abstract

IGNITION PRE-CHAMBER WITH ORIENTED VALVE The ignition pre-chamber with an oriented valve (1) comprises a stratification conduit (7) which opens into a combustion chamber (3) via a non-magnetic pre-chamber nose (62) in which is fixedly mounted a friction insert for an oriented valve (60), a valve with a guide pin (50) formed of a main valve body (8) and an orientation pin (15) that can translate within said insert (60) while said valve (50) has an external circular peripheral valve body guide bearing (64) and an external circular peripheral pin guide bearing bearing (66) which cooperate respectively with an internal valve body guide cylinder (63) and an internal orientation pin guide cylinder (65) provided in the friction insert for an oriented valve (60). Figure for the abbreviation: Fig. 1

Description

Title of the invention: Ignition pre-chamber with oriented flap

[0001] The present invention relates to an ignition pre-chamber with an oriented flap which forms an improvement of the ignition pre-chamber with a flap which is the subject of patent No. FR 3 061 743 published on August 16, 2019 and belonging to the applicant.

[0002] The pre-chamber ignition with oriented valve according to the present invention combines advantageously with the improvements of the pre-chamber ignition with valve according to patent FR 3 061 743, said improvements having been the subject of several patent applications.

[0003] Among the said improvements, we note the "magnetic valve return device" which is the subject of French patent application No. 3 085 718 published on March 13, 2020, or the "ignition insert with active pre-chamber" for which French patent application was filed on May 13, 2019 under No. 1904961, or the "ignition pre-chamber with valve in reverse combustion direction" which was the subject of French patent application No. 2001508 of February 14, 2020, or even the patent entitled "valve with guide pin" published under No. WO2022079367.

[0004] These patents and patent applications have in common that they present, as do most state-of-the-art torch ignition devices intended for reciprocating internal combustion engines, an ignition pre-chamber formed by a stratification cavity provided in the cylinder head of an internal combustion engine.

[0005] The strategy served by said patents, patent applications, and devices, is notably known by the Anglo-Saxon term "Turbulent Jet Ignition".

[0006] According to said patents and patent applications, the stratification cavity is, on the one hand, connected to the combustion chamber of the internal combustion engine by a stratification conduit, and on the other hand, receives a stratification injector which can inject into said cavity a pilot charge previously pressurized by compression means, said charge being made up of an oxidizer-fuel mixture easily ignited by means of a spark.

[0007] It is noted that the combustion chamber receives a main charge which can be either undiluted or diluted with air or with recirculated exhaust gases, dilution in particular allowing to maximize the energy efficiency of the internal combustion engine.

[0008] The said patents and patent applications belonging to the applicant differ from the prior art in that the stratification duct exposes a valve sealing seat on which a stratification valve can rest to close said duct. In so doing, said valve isolates the stratification cavity from the combustion chamber of the internal combustion engine.

[0009] When, on the other hand, said valve is moved away from said seat to rest on a valve stop on the chamber side directly or via a damping chamber as described in French patent application No. 3 085 718, said valve forms with the lamination conduit a torch ignition pre-chamber which communicates simultaneously, on the one hand, with the lamination cavity, and on the other hand, with the combustion chamber via gas ejection ports.

[0010] This particular configuration allows a pilot charge to be introduced into the stratification cavity, which remains perfectly flammable regardless of the nature and composition of the main charge formed in the combustion chamber. Indeed, said main charge and said pilot charge can no longer mix because the two charges are hermetically sealed by the stratification valve.

[0011] This advantage is decisive, because the composition, pressure and temperature of the pilot charge can be radically different from those of the main charge.

[0012] The stratification valve thus makes it possible to avoid one of the main pitfalls of torch pre-chambers which can be described as "open", that is to say without a stratification valve, which, according to the state of the art, imply that if a gaseous mixture which is difficult to ignite forms the main charge, said mixture also forms, in part and as a consequence of a mixture undergone, the pilot charge in the ignition pre-chamber even if said charge has been introduced into said pre-chamber by an injector in the form of a pre-prepared oxidizer-fuel gaseous mixture, or has been formed in said pre-chamber by injection of an additional liquid or gaseous fuel.

[0013] Indeed, in the case of "open" pre-chambers, the result of the mixing between the main charge and the pilot charge is that the latter is less able to deliver a high ignition power as the ignition of the main charge requires a high ignition power.

[0014] Conversely, and still in the case of "open" pre-chambers, when the main charge is formed of a slightly diluted and very reactive mixture which requires only a low ignition power in order to avoid the combustion of said charge generating excessively high pressure gradients and noise in the main chamber, the pilot charge is too energetic because it is partly formed of the mixture constituting the main charge from which it inherits the pressure and temperature.

[0015] In other words, without the stratification valve which, according to patent No. FR 3 061 743, allows the stratification duct to be closed, the pilot charge is necessarily formed partly from the mixture constituting the main charge and therefore, said pilot charge inherits partly the susceptibility to ignition and to the combustion of said main charge, and its energy content is directly related to the pressure imposed on it by said main charge, which is contrary to the need.

[0016] Indeed, the less reactive the main charge, the more powerful the pilot charge must be. Conversely, the more easily and quickly the main charge is flammable, the less energetic the pilot charge must be to prevent excessively rapid combustion of said main charge.

[0017] This is why the valve ignition pre-chamber of patent FR 3 061 743 forms an autonomous torch ignition device whose power can be freely adjusted, in order to find the best compromise between efficiency, pollutant emissions, and acoustic emissions of the internal combustion engine which receives it.

[0018] Having stated this, it can be seen in the figures of patent WO2022079367 that, advantageously, an orientation lug emerges from the axial opening face of the main body of the stratification valve, to form a guide lug valve.

[0019] The orienting pin cooperates with an axial guide orifice in which it is housed with minimal radial clearance, said orifice passing through a valve stop on the chamber side. Thus, said pin can slide longitudinally within said orifice without ever fully exiting it. In doing so, said pin orients the guide pin valve within the stratification conduit.

[0020] Upon reading patent WO2022079367, it is also noted that the guide nipple valve has a peripheral centering surface arranged around the periphery of its main valve body, said surface being able to come into contact with the internal wall of the stratification conduit to center said body in said conduit.

[0021] In patent WO2022079367, a valve damping chamber is formed by the stratification conduit, by an axial opening face, and by a chamber-side valve stop, the volume of said chamber being maximum when an axial obturation face of the guide-nipple valve rests on a conduit obturation seat of the stratification conduit, and minimum when the axial opening face rests on the chamber-side valve stop.

[0022] Patent WO2022079367 also states that the guide nipple valve can advantageously be coated in whole or in part with a material with a low coefficient of friction resistant to abrasive wear such as a "Diamond Like Coating" or a physical vapor phase deposition such as "Lonbond ® 90" developed by the "Lonbond ®" company of the "IHI" group, while the internal surfaces of the lamination conduit which come into contact with said valve are for example coated with low phosphorus electro-nickel.

[0023] As can be seen in the figures of patent WO2022079367, the lamination conduit includes a non-magnetic pre-chamber nose made of copper or stainless steel, coated or not with a highly abrasion-resistant anti-friction material.

[0024] The non-magnetic character of the constitutive material of the pre-chamber nose is necessary for the magnetic valve return device which is the subject of French patent application No. 3 085 718, without which the guide pin valve cannot close sufficiently quickly, particularly when said valve is applied to high-speed motors such as those used in automobiles.

[0025] In the figures of patent WO2022079367, it is noted that the pre-chamber nose is mounted shrink-fitted astride a gas ejection tube and an added non-magnetic sleeve, said nose receiving the valve stop on the chamber side and the axial guide orifice which houses the orientation pin with little clearance.

[0026] The non-magnetic attached sleeve can receive a conduit sealing seat which cooperates with an axial sealing face provided on the main valve body to seal the lamination conduit, said seat being able to receive a hard treatment resistant to abrasion and shocks such as "Tribobond ® 15".

[0027] It is noted that the non-magnetic pre-chamber nose must be made of a material which is not only non-magnetic to be compatible with the magnetic valve return device which is the subject of French patent application No. 3 085 718, but which also has high thermal conductivity, such as copper, so as to prevent the temperature of said nose from becoming excessive, the latter being directly exposed to the hot gases present in the combustion chamber of the internal combustion engine.

[0028] Indeed, if the non-magnetic pre-chamber nose is too hot, it can cause the untimely auto-ignition of the main charge contained in the combustion chamber, which could lead to the destruction of the internal combustion engine.

[0029] The problem is that the copper or copper alloy from which the non-magnetic pre-chamber nose can be made is a ductile and malleable material which needs to be covered with a hard coating to make it resistant to the abrasive wear induced by its friction with the peripheral centering surface of the guide pin valve on the one hand, and to that induced by the friction of the orientation pin with the axial guide orifice on the other hand.

[0030] Coating copper or copper alloy is not, however, suitable for the functional context of the guide pin valve when it is necessary to guarantee a long service life of the prechamber with guide pin valve which results from the combination of patents No. FR 3 061 743 and No. WO2022079367.

[0031] Indeed, the torch ignition pre-chamber is subjected to a high thermal load when ignition torches are ejected from said pre-chamber via gas ejection ports, at temperatures exceeding two thousand degrees Celsius.

[0032] For example, the chemical nickel coating is compatible with high mechanical strength copper alloys such as "C17500", but said coating is not sufficiently resistant to temperature and abrasion to meet the functional specifications of the prechamber with guide pin valve according to patent No. WO2022079367.

[0033] Indeed, in practice, the chemical nickel coating rapidly loses its mechanical properties with temperature, and it is repelled by the lamination flap, or even deposits itself on said flap by a succession of micro-fusions.

[0034] The problem is that copper cannot receive coatings resistant to very high temperatures which are ordinarily applied at temperatures between five hundred and eight hundred degrees Celsius.

[0035] One solution could be to replace the copper with non-magnetic stainless steel, but the thermal conductivity of said steel is insufficient.

[0036] It is therefore in order to resolve the various problems which have just been described and the resulting dilemmas that according to the ignition pre-chamber with oriented valve according to the invention and according to a particular embodiment of said pre-chamber, the stratification valve and the orientation nipple which form the valve with guide nipple are no longer guided directly by the constitutive material of the non-magnetic pre-chamber nose, but by means of guide means made of a hard material, resistant to abrasion, and compatible with the most effective anti-friction coatings which are generally deposited at high temperature.

[0037] In this respect, the ignition pre-chamber with a valve oriented according to the invention results in a pre-chamber with a valve: • Whose non-magnetic pre-chamber nose can be made with a non-magnetic material with high thermal conductivity such as copper, without prejudice to the mechanical strength and service life of said nose; • Whose lifespan is compatible with that of a mass-produced automotive engine, and whose operation remains stable during said lifespan, guaranteeing the internal combustion engine that receives it optimal efficiency and operation throughout its lifespan; • Whose mass production presents no particular difficulty; • Whose cost price is compatible with the economic constraints of the market for automobiles produced in very large series.

[0038] It is understood that the ignition pre-chamber with oriented valve according to the invention can not only be applied to the pre-chamber with guide pin valve according to patent No. WO2022079367, but also to any other application similar in its concept and principle which could advantageously take advantage of the characteristics and functionalities of said pre-chamber.

[0039] The pre-chamber ignition chamber with an oriented valve according to the invention is arranged in an internal combustion engine cylinder head which covers a combustion chamber, said pre-chamber comprising a stratification cavity into which ignition means and a stratification injector open, said cavity being connected to the combustion chamber by a stratification conduit which opens into said chamber in the form of a non-magnetic pre-chamber nose in which a stratification valve can translate which comprises a main valve body the latter comprising, on the side of the stratification cavity, an axial sealing face which can cooperate with a conduit sealing seat arranged in the stratification conduit to close the latter while said valve is oriented by an orientation pin which emerges from the main valve body and which can slide in an axial guide orifice arranged in said nose,said body and said nipple together forming a guide nipple valve, while the non-magnetic pre-chamber nose forms with said valve, and when the latter does not obstruct the stratification duct, a torch ignition pre-chamber which connects the stratification cavity to the combustion chamber via at least one gas ejection orifice, and comprises: , • A friction insert for an oriented valve which is fixedly mounted in the nose of the non-magnetic pre-chamber and which houses all or part of the guide pin valve, said insert replacing the nose of the non-magnetic pre-chamber to house the axial guide orifice. • At least one external peripheral circular guide bearing for the valve body, projecting outwards and on the external periphery of the main valve body, said bearing being, at least in part, resistant to abrasive wear; • At least one external peripheral circular bearing surface for guiding the nipple, projecting outwards and on the external periphery of the orientation nipple, said bearing surface being resistant to abrasive wear; • At least one internal valve body guide cylinder, which is provided in the friction insert for the oriented valve and which houses, in whole or in part, the main valve body, the latter being able to translate within said cylinder, in which it is guided by the external peripheral circular valve body guide bearing, the internal diameter of said cylinder being substantially greater than the outer diameter of said bearing while the inner surface of said cylinder is, at least in part, resistant to abrasive wear. • At least one internal orientation pin guide cylinder which has the axial guide orifice and which houses in whole or in part the orientation pin, the latter being able to translate in said cylinder in which it is guided by the external peripheral circular pin guide bearing, the internal diameter of said cylinder being substantially greater than the external diameter of said bearing while the internal surface of said cylinder is, at least in part, resistant to abrasive wear.

[0040] The pre-ignition chamber with oriented valve according to the invention includes a friction insert for oriented valve which is made of a non-magnetic material with high thermal and mechanical resistance.

[0041] The pre-ignition chamber with oriented valve according to the invention comprises a friction insert for oriented valve which forms, with an axial opening face oriented towards the combustion chamber that the main valve body presents on the one hand, and with the orientation nipple on the other hand, a valve damping chamber.

[0042] The pre-ignition chamber with oriented valve according to the invention comprises an axial guide orifice which has a damping counterbore at its end which opens into the valve damping chamber, said counterbore cooperating with a damping shoulder which comprises the orientation pin.

[0043] The pre-ignition chamber with oriented valve according to the invention includes a damping groove which is directly or indirectly connected to the combustion chamber by at least one depressurization conduit.

[0044] The ignition pre-chamber with oriented valve according to the invention comprises a main valve body which includes in its external periphery a secondary sealing collar in the extension of the external peripheral circular bearing surface for guiding the valve body, the external diameter of said collar being less than the external diameter of said bearing surface.

[0045] The ignition pre-chamber with oriented valve according to the invention comprises a friction insert for oriented valve which is fixedly mounted in the nose of the non-magnetic pre-chamber by means of an elastic washer held in place in the nose of the non-magnetic pre-chamber by a circular retaining ring housed in a retaining ring groove provided in said nose.

[0046] The pre-ignition chamber with oriented valve according to the invention comprises an axial face of the circular stop ring which is in contact with the elastic washer which has a locking shoulder which can come into contact with the periphery of said washer, said shoulder preventing said stop ring from coming out of the stop ring groove.

[0047] The ignition pre-chamber with oriented valve according to the invention comprises a friction insert for oriented valve which is screwed into the nose of the non-magnetic pre-chamber by means of an insert thread which is present in said insert, said thread cooperating with a pre-chamber nose thread which is present in the nose of the non-magnetic pre-chamber.

[0048] The pre-ignition chamber with oriented valve according to the invention comprises a friction insert for oriented valve which is divided into three insert parts, the first insert part receiving the internal guide cylinder of the valve body, the second insert part forming an insert mounting body, and the third insert part receiving the internal guide cylinder of the orientation pin.

[0049] The pre-ignition chamber with an oriented valve according to the invention comprises a stratification conduit which forms a gas ejection tube at the end of which is provided the conduit sealing seat while a magnetic field source induces a magnetic field in said tube, said field attracting the stratification valve towards said tube and tending to bring said valve back into contact with the conduit sealing seat.

[0050] The pre-ignition chamber with an oriented valve according to the invention comprises a gas ejection tube which receives a non-magnetic attached sleeve on which the conduit sealing seat is provided.

[0051] The pre-ignition chamber with an oriented valve according to the invention includes a magnetic flux channeling groove which is provided on the periphery of the gas ejection tube (25) and in the vicinity of the conduit sealing seat.

[0052] The following description, with reference to the attached drawings given by way of non-limiting examples, will allow for a better understanding of the invention, its features, and the advantages it is likely to provide:

[0053] [Fig-1] is a partial schematic cross-sectional view of the ignition pre-chamber with oriented valve according to the invention, said view being centered on the friction insert for oriented valve which is fixedly mounted in the nose of the non-magnetic pre-chamber by means of an elastic washer itself held in place by a circular stop ring housed in a stop ring groove provided in said nose, the guide pin valve being closed, i.e. blocking the stratification channel while the volume of the valve damping chamber is at its maximum.

[0054] [Fig.2] is a partial schematic cross-sectional view of the oriented valve ignition pre-chamber according to the invention and according to the variant shown in [Fig.1], the guide pin valve being open and its axial opening face resting on the valve stop on the chamber side, said valve forming with the non-magnetic pre-chamber nose a torch ignition pre-chamber while the stratification conduit is connected with the combustion chamber and the volume of the valve damping chamber is minimal.

[0055] [Fig.3] is a schematic cross-sectional view of the ignition pre-chamber at oriented valve according to the invention and according to the variant shown in [Fig.1], in the environment of an internal combustion engine which receives said pre-chamber, the friction insert for oriented valve taking place at the end of an ignition insert with active pre-chamber as described in French patent application No. 1904961 belonging to the applicant, and cooperating with a spark plug and an electromechanically controlled stratification injector.

[0056] [Fig.4] is a three-dimensional view of the oriented valve ignition pre-chamber following the invention in the environment of an internal combustion engine, made from the schematic cross-section shown in [Fig.3].

[0057] [Fig.5] is an exploded three-dimensional view of the valve ignition pre-chamber oriented according to the invention and according to the variant and environment shown in figures 1 to 4, but without the internal combustion engine.

[0058] [Fig.6] is a partial schematic cross-sectional view of the ignition pre-chamber with an oriented valve according to the invention, said view being centered on the friction insert for oriented valve which is screwed into the nose of non-magnetic pre-chamber by means of an insert thread and a pre-chamber nose thread, while the guide pin valve is open to form with the non-magnetic pre-chamber nose a torch ignition pre-chamber, the volume of the valve damping chamber being minimal.

[0059] [Fig.7] is a partial schematic cross-sectional view of the ignition pre-chamber at oriented valve according to the invention, said view being centered on the friction insert for oriented valve which is divided into three insert parts, the first receiving the internal guide cylinder of valve body, the second forming an insert mounting body, and the third receiving the internal guide cylinder of orientation pin, while the valve with guide pin is open to form with the non-magnetic pre-chamber nose a torch ignition pre-chamber, the volume of the valve damping chamber being minimal.

[0060] DESCRIPTION OF THE INVENTION:

[0061] Figures 1 to 7 show the pre-chamber ignition with oriented valve 1 according to the invention, various details of its components, its variants, and its accessories.

[0062] As shown in Figures 1 to 4 and Figures 6 and 7, the pre-ignition chamber with oriented valve 1 is mainly intended to be fitted in an internal combustion engine cylinder head 2 which covers a combustion chamber 3, said pre-chamber 1 comprising a stratification cavity 4 into which ignition means 5 and a stratification injector 6 open.

[0063] As can be seen in figures 1 to 7, the stratification cavity 4 is connected to the combustion chamber 3 by a stratification conduit 7 which opens into said chamber 3 in the form of a non-magnetic pre-chamber nose 62.

[0064] It is noted in figures 1 to 7 that a stratification valve 61 can translate in the nose of the non-magnetic prechamber 62, said valve 61 comprising a main valve body 8 which has, on the side of the stratification cavity 4, an axial obturation face 10, the latter being able to cooperate with a conduit obturation seat 11 arranged in the stratification conduit 7 to obturation the latter 7.

[0065] It is noted in figures 1 to 7 that the stratification flap 61 is oriented by an orientation pin 15 which emerges from the main flap body 8 and which can slide in an axial guide orifice 17 provided in said nose 62, said body 8 and said pin 15 together forming a flap with guide pin 50.

[0066] As has been shown particularly visibly in figures 2, 6 and 7, the non-magnetic prechamber nose 62 forms with the guide pin valve 50, when the latter does not close the stratification conduit 7, a torch ignition prechamber 9 which puts the stratification cavity 6 in relation with the combustion chamber 3 by way of at least one gas ejection orifice 16.

[0067] Figures 1 to 7 show that the ignition pre-chamber with oriented valve 1 according to the invention comprises a friction insert for oriented valve 60, made of a single piece as shown in Figures 1 to 6 or which is formed of several pieces assembled as shown in [Fig.7], said insert 60 being fixedly mounted in the nose of the non-magnetic pre-chamber 62.

[0068] It is noted that the friction insert for the oriented valve 60 could be, as an alternative not shown, formed of two separate parts included in the non-magnetic pre-chamber nose 62, the first part forming the internal guide cylinder of the valve body 63 while the second forms the internal guide cylinder of the orientation pin 65.

[0069] The friction insert for the oriented valve 60 shown in Figures 1 to 7 houses in all or part of the guide nipple valve 50, said insert 60 replacing the non-magnetic pre-chamber nose 62 to house the axial guide orifice 17.

[0070] Particularly visible in figures 1, 2, 6 and 7, it is noted that the pre-ignition chamber with oriented valve 1 according to the invention also includes at least one external peripheral circular valve body guide bearing 64 arranged in projection and on the external periphery of the main valve body 8, said bearing 64 being, at least in part, resistant to abrasive wear.

[0071] As illustrated in figures 1, 2, 6 and 7, the external peripheral circular guide bearing of the valve body 64 may advantageously have a convex axial profile which prevents said bearing 64 from exposing a sharp edge.

[0072] Similarly, the pre-ignition chamber with oriented valve 1 according to the invention also includes at least one external peripheral circular bearing surface for guiding a nipple 66 arranged in projection and on the external periphery of the orientation nipple 15, said bearing surface 66 being resistant to abrasive wear.

[0073] It can be seen in figures 1, 2, 6 and 7 that the external peripheral circular bearing surface for guiding the nipple 66 can also advantageously have a convex axial profile which prevents said bearing 66 from exposing a sharp edge.

[0074] Figures 1, 2, 6 and 7 also illustrate that the pre-ignition chamber with oriented valve 1 according to the invention also includes at least one internal valve body guide cylinder 63 which is arranged in the friction insert for oriented valve 60 and which houses all or part of the main valve body 8.

[0075] It is noted that the main valve body 8 can translate in the internal valve body guide cylinder 63 in which it is guided by the external peripheral circular valve body guide bearing 64, the internal diameter of said cylinder 63 being substantially greater than the external diameter of said bearing 64 while the internal surface of said cylinder 63 is, at least in part, resistant to abrasive wear.

[0076] Figures 1, 2, 6 and 7 also show that the pre-ignition chamber with oriented valve 1 according to the invention also includes at least one internal cylinder for guiding the orientation pin 65 which is present in the axial guide orifice 17 and which houses in whole or in part the orientation pin 15.

[0077] It is noted that the orientation stud 15 can translate in the internal orientation stud guide cylinder 65 in which it is guided by the external peripheral circular stud guide bearing 66, the internal diameter of said cylinder 65 being substantially greater than the external diameter of said bearing 66 while the internal surface of said cylinder 65 is, at least in part, resistant to abrasive wear.

[0078] It is noted that according to the pre-ignition chamber with oriented valve 1 according to the invention, the friction insert for oriented valve 60 can advantageously be made of a non-magnetic material with high thermal and mechanical resistance.

[0079] As a variant of the pre-ignition chamber with oriented valve 1 according to the invention, particularly visible in figures 1, 2, 6 and 7, the friction insert for oriented valve 60 can form, with an axial opening face 13 oriented towards the combustion chamber 3 presented by the main valve body 8 on the one hand, and with the orientation stud 15 on the other hand, a valve damping chamber 18.

[0080] Thus, when the guide pin valve 50 opens to form a torch ignition pre-chamber 9 with the non-magnetic pre-chamber nose 62, the valve damping chamber 18 dampens any potential shock that may occur between the axial opening face 13 of said valve 50 and a valve stop on the chamber side 14 which stops said valve 50 in its travel towards the combustion chamber 3, said stop 14 being none other than the bottom of the valve damping chamber 18.

[0081] In this case, the axial guide orifice 17 may advantageously have a damping counterbore 47 at its end which opens into the valve damping chamber 18, said counterbore 47 cooperating with a damping shoulder 46 which comprises the orientation pin 15.

[0082] It is noted that the damping counterbore 47 and the damping shoulder 46 are positioned so that the guide pin valve 50 can travel the first part of its stroke towards the valve stop on the chamber side 14 with the least possible braking by the valve damping chamber 18.

[0083] Indeed, as long as the damping shoulder 46 has not reached the level of the damping counterbore 47, the gases 19 contained in the damping chamber of the valve 18 can freely exit the latter towards the combustion chamber 3, via the gap left between said shoulder 46 and said counterbore 47, and then via the depressurization conduits 48.

[0084] When the damping shoulder 46 reaches the level of the damping counterbore 47, the gases 19 are strongly compressed by the passage restriction thus formed, so that during the second part of its stroke towards the valve stop on the chamber side 14, the guide pin valve 50 is braked, which reduces the power of any shock that may occur between the axial opening face 13 and the valve stop on the chamber side 14.

[0085] This particular configuration of the friction insert for the oriented valve 60 and the guide pin valve 50 gives the ignition pre-chamber with oriented valve 1 according to the invention a long service life

[0086] According to this last variant, it can be seen in figures 1, 2, 6 and 7 that the damping counterbore 47 can be directly or indirectly connected to the combustion chamber 3 by at least one depressurization conduit 48.

[0087] Figures 1, 2, 6 and 7 illustrate that according to another embodiment of the oriented valve ignition pre-chamber 1 according to the invention, the main valve body 8 may include in its outer periphery a secondary sealing collar 73 in the extension of the outer peripheral circular guide surface of the valve body 64, the outer diameter of said collar 73 being less than the outer diameter of said surface 64.

[0088] It is noted that the secondary sealing collar 73 forms a labyrinth or a baffle which opposes resistance to the passage of gas 19 which enters or leaves the damping chamber of the valve 18.

[0089] As another embodiment of the pre-ignition chamber with oriented valve 1 according to the invention, particularly visible in Figures 1, 2 and 5, the friction insert for The oriented valve 60 can be fixedly mounted in the nose of the non-magnetic pre-chamber 62 by means of an elastic washer 51 for example of the "Belleville" type known per se, held in place in the nose of the non-magnetic pre-chamber 62 by a circular stop ring 52 housed in a stop ring groove 54 provided in said nose 62.

[0090] In this case, the circular retaining ring 52 and the elastic washer 51 can advantageously be made of a stainless, non-magnetic metal, retaining high mechanical resistance at high temperatures such as "Inconel ®".

[0091] In this case, the axial face of the circular retaining ring 52 which is in contact with the elastic washer 51 may advantageously include a locking shoulder 53 which can come into contact with the periphery of said washer 51, said shoulder 53 preventing said retaining ring 52 from coming out of the retaining ring groove 54.

[0092] It is noted in [Fig.7] that the gas ejection ports 16 can each receive an inlet chapel 29 which is arranged in the nose of the non-magnetic pre-chamber 62 and which is interposed between the torch ignition pre-chamber 9 and the gas ejection port 16 with which it cooperates.

[0093] This particular configuration of the ignition pre-chamber with oriented valve 1 according to the invention allows the gas ejection orifices 16 to form a very closed angle with the longitudinal axis of the non-magnetic pre-chamber nose 62.

[0094] In figures 6 and 7, it has been shown that according to the ignition pre-chamber with oriented valve 1 according to the invention, the friction insert for oriented valve 60 can be screwed in whole or in part into the nose of non-magnetic pre-chamber 62 by means of an insert thread 34 which is present in said insert 60, said thread 34 cooperating with a pre-chamber nose thread 35 which is present in the nose of non-magnetic pre-chamber 62.

[0095] It is noted that the insert thread 34 can be male and the prechamber nose thread 35 female, or vice versa.

[0096] Regardless of the screwed configuration, the friction insert for the oriented valve 60 can, once screwed into or around the non-magnetic pre-chamber nose 62, be stopped from rotating by non-represented stopping means such as at least one tab, the folding of a part of the constituent material of the non-magnetic pre-chamber nose 62 into at least one housing or slot provided in the insert thread 34, at least one pin, or by any other stopping means known to those skilled in the art.

[0097] Fig. 7 shows that the friction insert for the oriented valve 60 can be divided into three insert parts 37, 38, 39, the first insert part 37 receiving the internal guide cylinder of the valve body 63, the second insert part 38 forming an insert mounting body 36, while the third insert part 39 receives the internal guide cylinder of the orientation pin 65.

[0098] This particular configuration of the ignition pre-chamber with oriented valve 1 according to the invention allows each part of insert 37, 38, 39 to be made of one or more materials that are as suitable as possible for the function assigned to each said part 37, 38, 39.

[0099] Fig. 7 also shows that the stratification conduit 7 can form a gas ejection tube 25 at the end of which is provided the conduit sealing seat 11 while a magnetic field source 23 induces a magnetic field in said tube 25, said field attracting the stratification valve 61 towards said tube 25 and tending to bring said valve 61 back into contact with the conduit sealing seat 11.

[0100] As shown in figures 1, 2, 5, 6 and 7, the gas ejection tube 25 can receive an added non-magnetic sleeve 26 on which the conduit sealing seat 11 is provided.

[0101] Nevertheless, whatever the configuration chosen for the gas ejection tube 25, a magnetic flux channeling groove 28 can be provided on the periphery of the gas ejection tube 25 and in the vicinity of the conduit sealing seat 11, said groove 28 allowing to increase the effectiveness of the magnetic field produced by the magnetic field source 23 in attracting the stratification valve 61 and in returning the latter to contact with the conduit sealing seat 11.

[0102] It should be noted that the magnetic flux channeling throat 28 can adopt any shape imaginable by a person skilled in the art, without restriction.

[0103] OPERATION OF THE INVENTION:

[0104] The operation of the pre-ignition chamber with oriented valve 1 according to the invention can be easily understood from the view of figures 1 to 7.

[0105] Figures 3 and 4 show the environment of the invention which is mainly made up of the cylinder head of an internal combustion engine 2 of an internal combustion engine 79 the latter comprising a piston 80 and a cylinder 81 which together with said cylinder head 2 form a combustion chamber 3.

[0106] It has been shown, particularly in Figures 1 to 4 and in Figures 6 and 7, that the lamination conduit 7 has a gas ejection tube 25 made, according to this example, of stainless steel with high magnetic permeability and low magnetic remanence, said conduit 7 also being able to include, according to the variants particularly visible in Figures 1, 2 and 6, an added non-magnetic sleeve 26 which is made for example of "Inconel ® 718", which is shrink-fitted onto the gas ejection tube 25, and which receives the conduit sealing seat 11, the latter being able to receive a hard treatment resistant to abrasion and shock such as "Tribobond ® 15".

[0107] According to a particular configuration, the non-magnetic insert sleeve 26 can be made of high-hardness through-hardness hardened magnetic steel such as "Caldie®" from the company "Uddeholm", said steel being coated with a low coefficient layer friction and even harder and more resistant to abrasion and impacts such as "Tribobond ® 15".

[0108] Fig. 7 shows that the stratification conduit 7 may not receive an added non-magnetic sleeve 26, the conduit sealing seat 11 being in this case arranged directly at the end of the gas ejection tube 25.

[0109] If the non-magnetic added sleeve 26 is, according to a particular embodiment of the pre-ignition chamber with oriented valve 1 according to the invention, made of magnetic steel of any kind, said sleeve 26 can receive a magnetic flux channeling groove 28 like that shown in [Fig.7], said groove 28 being provided directly on the periphery of the gas ejection tube 25.

[0110] The magnetic flux channeling groove 28 allows the shape of the magnetic field to be distorted at the level of the conduit sealing seat 11, which has the effect of amplifying the magnetic return force of the guide pin valve 50 on the conduit sealing seat 11 with which it cooperates.

[0111] In figures 1 to 4 and in figures 6 and 7, it can be seen that the stratification conduit 7 opens into the combustion chamber 3 in the form of a non-magnetic pre-chamber nose 62 made of copper alloy, for example a Copper-Beryllium-Cobalt of type “C17500”.

[0112] The “C17500” alloy has the advantage of being non-magnetic, in addition to offering a good compromise between high thermal conductivity on the one hand, and acceptable mechanical resistance at high temperatures on the other.

[0113] In figures 1, 4 and 6, it has been shown that the non-magnetic pre-chamber nose 62 can be mounted shrink-fitted astride the gas ejection tube 25 and the non-magnetic added sleeve 26, whereas in [Fig.7], said nose 62 is directly mounted on the gas ejection tube 25.

[0114] Figures 1 to 7 show that the non-magnetic pre-chamber nose 62 made of copper alloy houses a friction insert for an oriented valve 60 which is made of a non-magnetic material with high thermal and mechanical resistance such as "Inconel ® 718".

[0115] In figures 1 to 5, said insert 60 is fixedly mounted in the nose of the non-magnetic pre-chamber 62 by means of an elastic washer 51 held in place by a circular retaining ring 52 housed in a retaining ring groove 54 provided in said nose 62, while in figures 6 and 7, it has been shown that said insert 60 can be screwed into said nose 62.

[0116] In general, it should be noted that the operation of the guide pin valve 50 in the friction insert for oriented valve 60 is analogous to that described in patent No. WO2022079367, the objective of said friction insert 60 not being to modify said operation, but rather to ensure that the latter and the valve ignition pre-chamber 1 as a whole have great stability over time, and great durability.

[0117] As has been shown particularly visibly in figures 1, 2 and 6, the friction insert for oriented valve 60 can be fixedly mounted in the nose of non-magnetic prechamber 62 by means of an elastic washer 51 which is here and by way of example of the "Belleville" type, said washer 51 being held in place in said nose 62 by a circular retaining ring 52 housed in a retaining ring groove 54 provided in said nose 62.

[0118] By way of another non-limiting example, the elastic washer 51 and the circular retaining ring 52 can advantageously be made of "Inconel ®", a stainless and non-magnetic metal which retains high mechanical resistance at high temperatures.

[0119] Regardless of the method of attachment in the non-magnetic pre-chamber nose 62, the friction insert for the oriented valve 60 can be mounted, at least locally, clamped in the non-magnetic pre-chamber nose 62 to ensure maximum thermal cohesion between said insert 60 and said nose 62 so that during the combustion of a main charge 27 in the combustion chamber 3, the heat received by the friction insert for the oriented valve 60 from the hot gases 19 with which it is in contact can be efficiently dissipated by conduction via the non-magnetic pre-chamber nose 62

[0120] An alternative may consist, on the contrary, of mounting the friction insert for the oriented valve 60 in the non-magnetic pre-chamber nose 62 with a slight play, this to avoid any creeping movement of said insert 60 in said nose 62 resulting from the slight shocks induced by the operation of the guide pin valve 50.

[0121] In [Fig. 1], the guide pin valve 50 has been shown in the "fully closed" position, i.e. with its axial sealing face 10 in contact with the sealing seat of the conduit 11, so that the stratification conduit 7 is sealed and no gas 19 can flow from the stratification cavity 4 to the combustion chamber 3 or vice versa, the volume of the valve damping chamber 18 being maximum.

[0122] Figures 2, 6 and 7 show the guide pin valve 50 in the "fully open" position, i.e. with its axial opening face 13 in contact with a valve stop on the chamber side 14 presented by the friction insert for the oriented valve 60, so that the stratification conduit 7 is also fully open.

[0123] The guide pin valve 50 being in said position shown in figures 2, 6 and 7, it forms with the non-magnetic pre-chamber nose 62 a torch ignition pre-chamber 9 through which the gases 19 can flow from the stratification cavity 4 to the combustion chamber 3, the volume of the valve damping chamber 18 being minimal.

[0124] In figures 1, 2, 6 and 7, it can be seen that an external peripheral circular guide bearing for the valve body 64 is provided in projection and on the external periphery of the main valve body 8, said bearing 64 being made resistant to abrasive wear for example by applying a surface coating such as "Lonbond ® 90".

[0125] It is noted that the external peripheral circular guide bearing of the valve body 64 cooperates with an internal valve body guide cylinder 63 which is arranged in the friction insert for the oriented valve 60 and which largely houses the main valve body 8, whether its axial sealing face 10 is in contact with the sealing seat of the conduit 11 or not.

[0126] Thus, the guide nipple valve 50 can translate in the internal guide cylinder of the valve body 63 in which it is guided by its external peripheral circular guide bearing of the valve body 64.

[0127] To avoid any jamming whether the internal combustion engine 79 is hot or cold, the inner diameter of the inner guide cylinder of the valve body 63 is always substantially greater than the outer diameter of the outer peripheral circular guide bearing of the valve body 64, while the inner surface of said cylinder 63 is made resistant to abrasive wear, for example by means of a surface coating such as "Lonbond ® 90".

[0128] Similarly, it can be seen in Figures 1, 2, 6 and 7 that an external peripheral circular bearing surface for guiding the lug 66 is provided in projection and on the external periphery of the orientation lug 15, said bearing surface 66 being made resistant to abrasive wear for example by also applying to it a surface coating such as "Lonbond ® 90".

[0129] Similarly, the external peripheral circular bearing for guiding the nipple 66 cooperates with an internal orientation nipple guide cylinder 65 arranged inside the friction insert for the oriented valve 60, said cylinder 65 housing almost entirely, according to the embodiment of the oriented valve ignition pre-chamber 1 according to the invention shown in figures 1, 2, 6 and 7, the orientation nipple 15, and this, whether the axial sealing face 10 of the main valve body 8 is in contact with the conduit sealing seat 11, or is away from said seat 11.

[0130] Thus, the orientation stud 15 can translate in the internal orientation stud guide cylinder 65 in which it is guided by the external peripheral circular stud guide bearing 66.

[0131] To prevent any jamming whether the internal combustion engine 79 is hot or cold, the inner diameter of the inner guide cylinder of the orientation pin 65 is always substantially larger than the outer diameter of the outer peripheral circular bearing surface of the pin guide 66, while the inner surface of said cylinder 65 is made resistant to abrasive wear, for example by means of a surface coating such as "Lonbond ® 90".

[0132] It can be seen in figures 1, 2, 6 and 7 that the external peripheral circular bearing surface for guiding the valve body 64 and the external peripheral circular bearing surface for guiding the nipple 66 are barrel-shaped with a large radius, these bearing surfaces having here, respectively and by way of non-limiting example, a longitudinal radius of eight and twenty millimeters.

[0133] These large radii lead to low contact pressures exerted during the operation of the internal combustion engine 79 by said bearings 64, 65 on their respective cylinders 63, 65.

[0134] Furthermore, the particular configuration of the guide pin valve 50 according to the oriented valve ignition pre-chamber 1 according to the invention allows for simple and lower cost mass production of said valve 50 compared to a solution which would provide for example a first valve body guide means made protruding inside a friction insert fixed in the nose of the non-magnetic pre-chamber 62 the main valve body 8 being cylindrical, and a second orientation pin guide means made protruding inside said insert, the orientation pin 15 also being cylindrical.

[0135] Because indeed, the external rectification of the guide pin valve 50 of the ignition prechamber with oriented valve 1 according to the invention remains simple and industrially accessible, even if the external peripheral circular guide surface of the valve body 64 and the external peripheral circular guide surface of the pin 66 are not cylindrical, and even if the manufacturing tolerances are tight, by only a few microns.

[0136] The same applies to the internal cylindrical grinding necessary to finish the internal guide cylinder of the valve body 63 and the internal guide cylinder of the orientation pin 65 of the friction insert for the oriented valve 60 of the ignition pre-chamber with oriented valve 1 according to the invention, said grinding remaining simple given the simplicity of the shapes to be machined.

[0137] It is also noted that, insofar as, as provided for in the pre-ignition chamber with oriented valve 1 according to the invention, the orientation pin 15 has an external peripheral circular bearing surface for guiding the pin 66, projecting from its outer periphery, the section exposed by said pin 15 to the pressure difference between that prevailing in the combustion chamber 3 of the internal combustion engine 79 and that prevailing in the torch pre-ignition chamber 9 when the guide pin valve 50 is open applies to a larger section, which allows said pressure difference to exert a greater closing force on said valve 50, which gives the latter more efficient operation when the internal combustion engine 79 operates at high rotational speeds.

[0138] It is noted, particularly in figures 1, 2, 6 and 7, that the orientation pin 15 has a damping shoulder 46 which cooperates with a damping counterbore 47 arranged at the entrance of the axial guide orifice 17, said counterbore 47 opening into the damping chamber of the valve 18.

[0139] This particular configuration of the friction insert for the oriented valve 60 and the guide pin valve 50 allows the latter to travel the first part of its stroke towards the valve stop on the chamber side 14 with the least possible braking by the valve damping chamber 18.

[0140] Indeed, as long as the damping shoulder 46 has not reached the level of the damping counterbore 47, the gases 19 contained in the damping chamber of the valve 18 can freely exit the latter towards the combustion chamber 3, via the gap left between said shoulder 46 and said counterbore 47, and then via the depressurization conduits 48.

[0141] When the damping shoulder 46 reaches the level of the damping counterbore 47, the gases 19 are strongly compressed by the passage restriction thus formed, so that during the second part of its stroke towards the valve stop on the chamber side 14, the guide pin valve 50 is braked, which reduces the power of any shock that may occur between the axial opening face 13 and the valve stop on the chamber side 14.

[0142] This particular configuration of the guide pin valve 50 gives the latter a long service life.

[0143] Figures 3 to 5 show the presence of a permanent return magnet 24, which forms a "magnetic return device for the flap" as described in French patent application No. 3 085 718.

[0144] The permanent return magnet 24 forms a source of magnetic field 23 and ensures the closing of the guide pin valve 50 after the latter has been opened by the rise in pressure of the gases 19 which occurred in the stratification cavity 4, this after a pilot charge 31 has been introduced into said cavity 4 by the stratification injector 6 which is here electromechanically controlled, and then ignited by a spark plug 33.

[0145] In figures 3 to 5, the electromechanically controlled stratification injector 6 is shown, which includes an injector needle 75 which, when lifted from its seat under the action of an electromagnetic injector actuator 76, introduces a pilot charge 31 into the stratification cavity 4.

[0146] When the electromagnetic injector actuator 76 ceases to be supplied with electrical current, the injector needle 75 is returned to its seat by a spring of needle return 77, the latter being isolated from the gases 19 constituting the pilot charge 31 by a spring isolation seal 78.

[0147] As illustrated in Figures 3 to 5, the position of the injector needle 75 is continuously returned to a computer not represented by an injector needle position sensor 82, the latter enabling said computer to precisely adjust the mass of the pilot charge 31 which is introduced into the stratification cavity 4 by the electromechanically controlled stratification injector 6.

[0148] For this purpose, said computer executes software which determines, continuously and from the lift of the injector needle 75 read by the injector needle position sensor 82, the mass of the pilot charge 31 which is introduced into the stratification cavity 4, said software correcting, where appropriate, said lift so that the mass of pilot charge 31 actually introduced into the stratification cavity 4 corresponds to that required for the optimal operation of the internal combustion engine 79.

[0149] Figures 3 to 5 show that the stratification cavity 4 is arranged in an active pre-chamber ignition insert 42 similar to that described in French patent application No. 1904961 of May 13, 2019 belonging to the applicant, said insert 42 being held fixedly in the cylinder head of the internal combustion engine 2 by insert clamping means 43.

[0150] As seen previously, the operation of the guide pin valve 50 in the context of the ignition prechamber with oriented valve 1 according to the invention is comparable to that described in patent No. WO2022079367.

[0151] However, contrary to said patent No. WO2022079367 and to what is shown in the initial patent FR 3 061 743 relating to a valve ignition pre-chamber, and contrary to what is shown in the improvement patents arising from said initial patent, there is no longer direct contact between the guide pin valve 50 and the non-magnetic pre-chamber nose 62, but via the friction insert for oriented valve 60.

[0152] This new configuration avoids having to coat the inside of the non-magnetic prechamber nose 62 with any coating whatsoever, because in fact, coatings which remain sufficiently hard and resistant to abrasion at high temperatures are notoriously incompatible with the copper alloy of which the non-magnetic prechamber nose 62 is made, due to the high temperature at which said coatings are applied, and due to the insufficient underlayer hardness of the substrate which is the copper alloy whatever its grade.

[0153] Advantageously, the guide insert for the oriented valve 60 can be made of a material such as "Inconel®", which is, under certain conditions, hard throughout so as to form a more favorable substrate for hard coatings, and which is resistant to high temperatures so as to be able to receive a wide range of hard coatings of the type “DLC”, “PVD” or of any type known to those skilled in the art, and in particular to receive a coating of type “Lonbond ® 90”.

[0154] It is noted that the "Inconel ®" from which, for example, the guide insert for oriented valve 60 is made can advantageously be hardened to a depth of between ten and thirty microns by a carbonitriding of the "Kolsterising ®" type, this treatment being notoriously mastered by the company "Bodycote".

[0155] Advantageously, the guide pin valve 50 being itself made of a material retaining high mechanical resistance at high temperature such for example as the chrome-molybdenum-vanadium magnetic steel "Caldie ®" from the company "Uddeholm", said valve 50 can also be covered with any type of anti-abrasion coating such as "Lonbond ® 90".

[0156] It follows from the above that the guide insert for the oriented valve 60 which comprises the ignition pre-chamber with oriented valve 1 according to the invention allows the choice of coatings compatible with each other, said coatings conferring a long service life both to the guide insert for the oriented valve 60, and to the guide pin valve 50 with which it cooperates.

[0157] To give the valve stop on the chamber side 14 which forms the bottom of the valve damping chamber 18 a high resistance to hammering, said stop 14 can advantageously be part of the guide insert for oriented valve 60 as has been clearly shown in figures 1, 2, 6 and 7, and benefits from the same mechanical strength and the same resistance to abrasion as any other part of said insert 60.

[0158] Thus, the core and high-temperature surface mechanical characteristics of the constituent material of the guide insert for the oriented valve 60 benefit all the functional surfaces of said insert 60 which cooperate with the guide pin valve 50.

[0159] Knowing that the guide pin valve 50 moves within the guide insert for the oriented valve 60 in almost permanent contact with the latter without benefiting from any lubrication, the person skilled in the art cannot fail to understand the decisive advantage that the guide insert for the oriented valve 60 according to the invention represents in the implementation and the durable operation of the guide pin valve 50, in addition to the geometric and functional characteristics favorable to mass production at a lower cost and to the most efficient possible valve closing return, as explained above.

[0160] Indeed, the guide pin valve 50 moves "dry" in the guide insert for the oriented valve 60, and is subjected to abrasive aggression that is all the more significant as foreign bodies such as mineral or carbonaceous particles can become lodged at high temperature between said valve 50 and said insert 60, whether between the circular bearing external peripheral guide for valve body 64 and internal guide for valve body 63, between the external peripheral circular guide for nipple 66 and the internal guide for orientation nipple 65, at the level of the duct sealing seat 11, or at the level of the valve stop on the chamber side 14.

[0161] It should be noted, however, that the carbon deposits which form on the rubbing surfaces of the guide pin valve 50 and the guide insert for oriented valve 60 can, on the contrary, protect said surfaces, by wearing away in place of the latter, while regenerating during the operation of the internal combustion engine 79.

[0162] It should be noted that the example of embodiment of the oriented valve ignition pre-chamber 1 according to the invention which has just been described is not limiting and that said pre-chamber 1 can be applied to other fields than only internal combustion engines.

[0163] Said pre-chamber 1 can for example be applied to gas nailers, firearms, or any device requiring the ignition of a main charge by means of a pilot charge with the best possible efficiency.

[0164] The possibilities of the pre-ignition chamber with oriented flap 1 according to the invention are not limited to the applications which have just been described and it must also be understood that the preceding description has been given only by way of example and that it does not in any way limit the field of said invention which would not be exceeded by replacing the execution details described by any other equivalent.

Claims

1. Demands Ignition pre-chamber with an oriented valve (1) arranged in an internal combustion engine cylinder head (2) which covers a combustion chamber (3), said pre-chamber (1) comprising a stratification cavity (4) into which ignition means (5) and a stratification injector (6) open, said cavity (4) being connected to the combustion chamber (3) by a stratification conduit (7) which opens into said chamber (3) in the form of a non-magnetic pre-chamber nose (62) in which a stratification valve (61) can translate, which includes a main valve body (8), the latter comprising, on the side of the stratification cavity (4),an axial sealing face (10) which can cooperate with a conduit sealing seat (11) provided in the stratification conduit (7) to seal the latter (7), whereas said valve (61) is oriented by an orientation pin (15) which emerges from the main valve body (8) and which can slide in an axial guide orifice (17), said body (8) and said pin (15) together forming a guide pin valve (50), while the non-magnetic pre-chamber nose (62) forms with said valve (50), and when the latter does not seal the stratification conduit (7), a torch ignition pre-chamber (9) which connects the stratification cavity (6) with the combustion chamber (3) via at least one gas ejection orifice (16), characterized in that it comprises:,

2. • A friction insert for an oriented valve (60) which is fixedly mounted in the nose of the non-magnetic pre-chamber (62) and which houses in whole or in part the guide pin valve (50) and the axial guide orifice (17); • At least one external peripheral circular guide bearing for the valve body (64) provided in projection and on the external periphery of the main valve body (8), said bearing (64) being, at least in part, resistant to abrasive wear; • At least one external peripheral circular bearing surface for guiding the nipple (66) arranged in projection and on the external periphery of the orientation nipple (15), said bearing surface (66) being resistant to abrasive wear; • At least one internal valve body guide cylinder (63) which is provided in the friction insert for oriented valve (60) and which houses all or part of the main valve body (8), the latter being able to translate in said cylinder (63) in which it is guided by the external peripheral circular valve body guide bearing (64), the internal diameter of said cylinder (63) being substantially greater than the external diameter of said bearing (64) while the internal surface of said cylinder (63) is, at least in part, resistant to abrasive wear; • At least one internal orientation pin guide cylinder (65) which has the axial guide orifice (17) and which houses in whole or in part the orientation pin (15), the latter being able to translate in said cylinder (65) in which it is guided by the external peripheral circular pin guide bearing (66), the internal diameter of said cylinder (65) being substantially greater than the external diameter of said bearing (66) while the internal surface of said cylinder (65) is, at least in part, resistant to abrasive wear. Ignition pre-chamber with oriented valve according to claim 1, characterized in that the friction insert for oriented valve (60) is made of a non-magnetic material with high thermal and mechanical resistance.

3. Pre-ignition chamber with oriented valve according to claim 1, characterized in that the friction insert for oriented valve (60) forms, with an axial opening face (13) oriented towards the combustion chamber (3) which is present in the main valve body (8) on the one hand, and with the orientation stud (15) on the other hand, a valve damping chamber (18).

4. Pre-ignition chamber with oriented valve according to claim 3, characterized in that the axial guide orifice (17) has a damping counterbore (47) at its end which opens into the valve damping chamber (18), said counterbore (47) cooperating with a damping shoulder (46) which comprises the orientation pin (15).

5. Pre-ignition chamber with oriented valve according to claim 4, characterized in that the damping counterbore (47) is directly or indirectly connected to the combustion chamber (3) by at least one depressurization conduit (48).

6. Ignition pre-chamber with oriented valve according to claim 1, characterized in that the main valve body (8) comprises in its external periphery a secondary sealing collar (73) in the extension of the external peripheral circular bearing surface for guiding valve body (64), the external diameter of said collar (73) being less than the external diameter of said bearing surface (64).

7. Ignition pre-chamber with oriented valve according to claim 1, characterized in that the friction insert for oriented valve (60) is fixedly mounted in the nose of non-magnetic pre-chamber (62) by means of an elastic washer (51) held in place in the nose of non-magnetic pre-chamber (62) by a circular retaining ring (52) housed in a retaining ring groove (54) provided in said nose (62).

8. Pre-ignition chamber with oriented valve according to claim 7, characterized in that the axial face of the circular stop ring (52) which is in contact with the elastic washer (51) has a locking shoulder (53) which can come into contact with the periphery of said washer (51), said shoulder (53) preventing said ring (52) from coming out of the stop ring groove (54).

9. Ignition pre-chamber with oriented valve according to claim 1, characterized in that the friction insert for oriented valve (60) is screwed into the nose of non-magnetic pre-chamber (62) by means of an insert thread (34) which is present in said insert (60), said thread (34) cooperating with a pre-chamber nose thread (35) which is present in the nose of non-magnetic pre-chamber (62).

10. Pre-chamber ignition with oriented valve according to claim 1, characterized in that the friction insert for oriented valve (60) is divided into three insert parts (37, 38, 39), the first insert part (37) receiving the internal guide cylinder of valve body (63), the second insert part (38) forming an insert mounting body (36), and the third insert part (39) receiving the internal guide cylinder of orientation pin (65).

11. Pre-ignition chamber with oriented valve according to claim 1, characterized in that the stratification conduit (7) forms a gas ejection tube (25) at the end of which is provided the conduit sealing seat (11) while a magnetic field source (23) induces a magnetic field in said tube (25), said field attracting the stratification valve (61) towards said tube (25) and tending to bring said valve (61) back into contact with the conduit sealing seat (11).

12. Pre-ignition chamber with oriented valve according to claim 11, characterized in that the gas ejection tube (25) receives a non-magnetic attached sleeve (26) on which the conduit sealing seat (11) is provided.

13. Pre-ignition chamber with oriented valve according to claim 11 or 12, characterized in that a magnetic flux channeling groove (28) is provided on the periphery of the gas ejection tube (25) and in the vicinity of the conduit sealing seat (11).

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