ENGINE WITH AN IGNITION INSERT WITH ACTIVE PRE-CHAMBER

Description

[0001] The present invention relates to an ignition insert with an active pre-chamber which makes it possible to house an active pre-chamber in a small and minimally intrusive manner in the cylinder head of an internal combustion engine.

[0002] There are many concepts of active pre-chambers, the latter being used as an ignition means to ignite a main charge contained in the combustion chamber of an internal combustion engine.

[0003] The term "active" pre-chamber is usually used to refer to pre-chambers into which, in addition to an electric spark plug known per se, at least one fuel injector, whether or not associated with an air injector, or at least one air and fuel mixture injector, opens.

[0004] For example, we know the pre-chamber concept known as "Turbulent Jet Ignition", patented and developed by the company "Mahle". Said concept - which was notably the subject of patent EP 3 001 008 A1 published on March 30, 2016 - provides a pre-chamber into which an electric spark plug on the one hand, and a fuel injector on the other hand, opens. Said pre-chamber is essentially intended to ignite main charges highly diluted with air, that is to say lean in gasoline and rich in oxygen.

[0005] Also known are patent application No. FR 3 061 743 published on July 13, 2018, relating to a valve-operated ignition pre-chamber, and that No. FR 3 060 222 published on June 15, 2018, relating to a spark plug with a shuttle electrode. These two applications belong to the applicant and have the particularity of separating the pre-chamber from the main chamber by means of a valve or a shuttle electrode. This innovative configuration offers numerous possibilities compared to conventional pre-chambers which communicate permanently with the engine's combustion chamber.

[0006] It should be noted that patent applications No. FR 3 061 743 and No. FR 3 060 222 were the subject of an improvement patent application No. 18 58111 dated September 10, 2018. This latter application belongs to the applicant and relates to the magnetic return of the valve or the shuttle electrode.

[0007] From the teaching described and illustrated in patent DE10016558, a method is known which consists of using a remotely initiated pilot chamber ignition device in a main combustion chamber of an internal combustion engine.

[0008] Generally speaking, all pre-chamber ignition devices provide that a pilot charge primarily composed of air and fuel is first introduced into said pre-chamber. Then, said pilot charge is ignited by a spark plug. As it burns, the pilot charge sees its pressure increased to the point that it is ejected at high temperature and high speed in the form of torches of burning gas into the three-dimensional space of the engine's combustion chamber. By passing through the volume of said chamber, said torches ignite the main charge it contains.

[0009] Compared to a simple spark plug, the much higher ignition power of torches combined with the formation of high-intensity, short-lived local turbulence allows for the rapid combustion of highly diluted main air and fuel charges with additional atmospheric air or with preferably pre-cooled recirculated exhaust gases.

[0010] The combination of powerful ignition and highly diluted charges allows the pre-ignition chambers by troche to significantly reduce the fuel consumption of spark-ignition internal combustion engines, in particular by limiting pumping losses and heat losses at the walls. The main charge being highly diluted and its combustion being rapid, said charge is also not very sensitive to knocking which makes it possible to provide for the engine which receives it a high volumetric ratio and an optimal ignition advance, these two particularities making it possible to confer a high efficiency to the thermodynamic cycle implemented.

[0011] One of the difficulties in implementing active ignition pre-chambers is the space occupied by the spark plug and the injector that the said pre-chambers receive, and which open into the very small volume of the said pre-chambers.

[0012] Furthermore, it is preferable to avoid any connecting conduit between the pre-chamber and the injector nozzle as illustrated by patent application No. FR 3 061 743. It is in fact difficult to propagate the flame previously initiated in the pre-chamber by the spark plug in such a conduit, the latter being cold, blocking the flame, forming a trap for unburned fuel, and strongly cooling the pilot charge due to the large internal surface area that it exposes in relation to its volume.

[0013] Active pre-chambers thus pose a problem of integration in internal combustion engines because in general, the spark plug and the injector are juxtaposed or almost juxtaposed as shown for example by patent EP 3 001 008 A1.

[0014] This arrangement results in a substantial radial bulk of the assembly consisting of the pre-chamber, the spark plug and the injector. In addition, said arrangement makes it difficult to produce pre-chambers of very small volume without the internal surface / volume ratio of said pre-chambers being very high and excessively promotes the cooling of the pilot charge gases once the latter have been brought to a high temperature.

[0015] It should also be noted that the significant bulk of the various components of the active pre-chamber reduces the space available for housing the water chambers which cool the cylinder head, the intake and exhaust ducts of the internal combustion engine, and the camshafts of said engine.

[0016] Furthermore, cooling the pre-chamber becomes potentially difficult to ensure if it is not in direct contact with the cooling water circulating in the water chambers of the cylinder head.

[0017] It should also be noted that installing an active pre-chamber in a pre-existing engine requires extensive modification of the cylinder head, which cannot accommodate the pre-chamber without undergoing substantial modifications. It is therefore necessary to support heavy investments to modify the cylinder head and to ensure its industrial production.

[0018] It is to resolve these various problems and drawbacks inherent in the installation of active pre-chambers in reciprocating internal combustion engines with controlled or compression ignition that, according to the invention and according to a particular embodiment, the active pre-chamber ignition insert allows: To house an active pre-chamber in the spark plug or injector well of practically any spark-ignition or diesel engine, that is to say by minimizing the modifications to which the cylinder head must be subjected; To cool said pre-chamber by putting the external surface directly in contact with the cooling water which circulates in the water chambers of the cylinder head which receives it; To produce active pre-chambers of very small volume and which offer a small surface / volume ratio, so that the heat exchanges between the gases contained in said pre-chambers and the internal wall of said pre-chambers remain limited;

[0019] Taking into account the above, the active pre-chamber ignition insert according to the invention makes it possible to meet an unmet need to be able to efficiently and inexpensively install an active pre-chamber on any type of reciprocating internal combustion engine.

[0020] The active pre-chamber ignition insert according to the invention is intended to be inexpensive to manufacture in large series, in order to remain compatible with the economic constraints of most of the applications for which it is intended, including automobiles.

[0021] It is understood that the active pre-chamber ignition insert according to the invention can be applied to any rotary or reciprocating internal combustion engine, whatever the type, whatever the gaseous, liquid or solid fuel it consumes, and whether its main charge is diluted with cooled or uncooled EGR, with a neutral gas of any nature whatsoever, or with a gas rich in oxygen or any other oxidant.

[0022] It is also understood that the pilot charge intended to ignite the main charge of any spark-ignition engine which receives the active pre-chamber ignition insert according to the invention may contain a fuel and / or an oxidant different from the fuel and / or oxidant which constitutes said main charge.

[0023] The internal combustion engine comprises a cylinder head which covers a cylinder to form with a piston a combustion chamber into which a main charge can be introduced, said cylinder head housing an ignition pre-chamber into which a spark plug and an injector nose of at least one injector open and into which a pilot charge can be introduced, said pre-chamber being able to communicate with the combustion chamber successively via a gas ejection duct and via at least one gas ejection orifice which opens into said chamber via a pre-chamber nose, said internal combustion engine comprising an ignition insert with active pre-chamber comprising: At least one insert well arranged in the cylinder head and having fixing means, said well opening on the one hand, outside the cylinder head via a large diameter insert introduction orifice, and on the other hand, into the combustion chamber via a pre-chamber nose orifice of smaller diameter, the two said diameters being connected to each other by at least one insert support shoulder; At least one cylindrical insert body consisting of one or more parts and in which are arranged in particular the ignition pre-chamber and the gas ejection duct, said body being housed with little play in the insert well, being indexed in rotation relative to the cylinder head, and ending with the pre-chamber nose which passes through the pre-chamber nose orifice, while said body has an insert support surface which rests directly or indirectly on the insert support shoulder;At least one insert spark plug well arranged in the cylindrical insert body, parallel to the axis of said body or forming a closed angle with respect to said axis and at the center or close to the center of said body, said spark plug well opening on the one hand, at the end of the cylindrical insert body which is axially opposite the pre-chamber nose, and on the other hand, into the ignition pre-chamber, said spark plug well receiving the spark plug or the injector nose; At least one radial injector orifice arranged radially in the cylindrical insert body but not necessarily perpendicular to the latter and in which the end of the injector nose or the spark plug is housed, said orifice connecting the ignition pre-chamber and / or the gas ejection duct with the external surface of the cylindrical insert body;At least one lateral injector well arranged in the cylinder head, said well receiving the body of the injector nose or the spark plug and connecting the exterior of the cylinder head with the insert well while the radial injector orifice is aligned with said well so that the end of the injector nose or the spark plug opens into the ignition pre-chamber and / or the gas ejection duct by successively passing through the lateral injector well and the radial injector orifice;Clamping means cooperating with the fixing means in order to directly or indirectly maintain the insert bearing surface of the cylindrical insert body pressed against the insert bearing shoulder. said pre-chamber nose housing a stratification valve which is pressed either against the end of the gas ejection duct to close the latter in a sealed manner, or against a valve surface on the chamber side to form with the gas ejection duct a torch ignition pre-chamber which communicates simultaneously on the one hand with the ignition pre-chamber via the gas ejection duct, and on the other hand with the combustion chamber via the gas ejection orifice;At least one magnetic field source (44) which is positioned on the cylindrical insert body (70), said source producing a magnetic field which tends to keep the stratification valve (13) pressed against the end of the gas ejection duct (76), the latter being made of a magnetic material (43) and forming at its contact with the stratification valve (13) a gas ejection tube (89) whose external diameter is smaller than that of said valve (13), said tube (89) being enclosed in a non-magnetic sleeve (85) made of a non-magnetic material (50). ;

[0024] The internal combustion engine according to the present invention comprises a pre-chamber nose which consists of an added nose which covers the gas ejection duct, the gas ejection orifice being arranged in said added nose.

[0025] The internal combustion engine according to the present invention comprises a space forming an insert cooling water chamber which is left between the cylindrical insert body and the insert well.

[0026] The internal combustion engine according to the present invention comprises a lateral injector well which consists of an openwork or non-continuous bore which communicates along its length with at least one cylinder head cooling water chamber which the cylinder head comprises.

[0027] The internal combustion engine according to the present invention comprises an insert clamping ferrule which bears on the ferrule clamping face by means of a restraining spring.

[0028] The internal combustion engine according to the present invention comprises clamping means which consist of at least one insert clamping ferrule having an external ferrule thread cooperating with the insert well fixing means which consist of an internal well thread, said ferrule being pierced in its center to allow the spark plug to pass through.

[0029] The internal combustion engine according to the present invention comprises an insert bearing surface which directly or indirectly forms a ball joint with the insert bearing shoulder while the cylindrical insert body directly or indirectly forms a ball joint with the clamping means.

[0030] The internal combustion engine according to the present invention comprises clamping means which bear on the cylindrical insert body by means of a sliding-swivel washer which can move radially either relative to the cylindrical insert body or relative to the clamping means.

[0031] The internal combustion engine according to the present invention comprises a sliding-swivel washer which is flexible and which forms a restraining spring.

[0032] The internal combustion engine according to the present invention comprises an injector nose which is held pressed in the radial injector orifice and against the cylindrical insert body by elastic clamping means which bear on the one hand on the injector, and on the other hand on the cylinder head.

[0033] The internal combustion engine according to the present invention comprises elastic clamping means which consist of a flange which bears on the injector on the one hand, and which is connected to the cylinder head by at least one flange screw on the other hand.

[0034] The following description, with reference to the attached drawings given as non-limiting examples, will enable a better understanding of the invention, the characteristics it presents, and the advantages it is likely to provide: [ Fig. 1 ] is a schematic sectional view of the active pre-chamber ignition insert according to the invention as it can be installed in the cylinder head of an internal combustion engine, said insert receiving as a variant a stratification valve held pressed against the end of the gas ejection duct by a magnetic field produced by a permanent magnet. Fig. 2] is a schematic sectional view framed on the cylindrical insert body of the active pre-chamber ignition insert according to the invention and according to the variant illustrated in figure 1 . [ Fig. 3 ] is an exploded three-dimensional view of the cylindrical insert body of the pre-chamber ignition insert according to the invention and of the main components with which said body cooperates, this according to the embodiment variant illustrated in figure 1 which provides a stratification valve and a permanent magnet. Fig. 4 ] is a three-dimensional cutaway view of the cylindrical insert body of the pre-chamber ignition insert according to the invention and of the main components with which said body cooperates, this according to the embodiment variant illustrated in figure 1 which provides a stratification valve and a permanent magnet. Fig. 5] is a schematic sectional view of the cylindrical insert body of the active pre-chamber ignition insert according to the invention as it can be installed in the cylinder head of an internal combustion engine, the insert bearing surface forming a ball joint with the insert bearing shoulder while the cylindrical insert body forms a ball joint with the clamping means by means of a sliding-ball joint washer. Fig. 6 ] is a schematic sectional view from above of the Figure 5 . DESCRIPTION OF THE INVENTION :

[0035] It was shown in figures 1 to 6 the active pre-chamber ignition insert 1 according to the invention, various details of its components, its variants, and its accessories.

[0036] The active pre-chamber ignition insert 1 is particularly intended for an internal combustion engine 2, the latter comprising a cylinder head 3 which covers a cylinder 4 to form, with a piston 31, a combustion chamber 5 into which a main charge 30 can be introduced.

[0037] As seen in figures 1 , 2 , 5 And 6 , the cylinder head 3 houses an ignition pre-chamber 71 into which a spark plug 12 and an injector nose 16 of at least one injector 8 open and into which a pilot charge 9 can be introduced, said pre-chamber 71 being able to communicate with the combustion chamber 5 successively via a gas ejection duct 76 and via at least one gas ejection orifice 24 which opens into said chamber 5 via a pre-chamber nose 75.

[0038] In figures 1 , 2 , 5 And 6, it has been shown that the active pre-chamber ignition insert 1 according to the invention comprises at least one insert well 72 arranged in the cylinder head 3. Said insert well 72 comprises fixing means which consist of an internal well thread 82 over part of its length. In addition, said well 72 opens on the one hand, outside the cylinder head 3 via a large diameter insert introduction orifice 78, and on the other hand, into the combustion chamber 5 via a smaller diameter pre-chamber nose orifice 77, the two said diameters being connected to each other by at least one insert support shoulder 79 which may for example be flat or conical.

[0039] In figures 1 to 6 , we see that the ignition insert with active pre-chamber 1 according to the invention has at least one cylindrical insert body 70 consisting of one or more parts and in which are in particular arranged the ignition pre-chamber 71 and the gas ejection duct 76.

[0040] The cylindrical insert body 70 is housed with little play in the insert well 72, is indexed in rotation relative to the cylinder head 3, and ends with the pre-chamber nose 75 which passes through the pre-chamber nose orifice 77. The cylindrical insert body 70 also has an insert bearing surface 80 which rests directly or indirectly on the insert bearing shoulder 79.

[0041] It is noted that when the cylindrical insert body 70 is introduced into the insert well 72 through the insert introduction orifice 78, said body 70 is stopped in its movement when the insert support shoulder 79 comes into contact with the insert support surface 80.

[0042] It is noted that a support seal 25 may be provided between the insert support surface 80 and the insert support shoulder 79 which provides a seal between the insert well 72 and the combustion chamber 5. Said seal 25 may be metallic such as annealed copper or be of any other type known to those skilled in the art.

[0043] As we see particularly in figures 2 , 4 And 5, the active pre-chamber ignition insert 1 according to the invention has at least one insert spark plug well 83 arranged in the cylindrical insert body 70, parallel to the axis of said body 70 or forming a closed angle with respect to said axis and at the center or close to the center of said body 70, said spark plug well 83 opening on the one hand, at the end of the cylindrical insert body 70 which is axially opposite the pre-chamber nose 75, and on the other hand, into the ignition pre-chamber 71. The insert spark plug well 83 receives the spark plug 12 or the injector nose 16.

[0044] We notice, particularly in figures 2 to 4 , that the active pre-chamber ignition insert 1 according to the invention comprises at least one radial injector orifice 88 arranged radially in the cylindrical insert body 70 but not necessarily perpendicular to the latter and in which the end of the injector nose 16 or the spark plug 12 is housed.

[0045] Said orifice 88 connects the ignition pre-chamber 71 and / or the gas ejection duct 76 with the external surface of the cylindrical insert body 70 while a seal can be provided between the radial injector orifice 88 and the injector nose 16 which takes the form of a segment, a seal or any other means known to those skilled in the art, and which prevents any leakage of liquid or gas between the ignition pre-chamber 71 and / or the gas ejection duct 76 and the external surface of the cylindrical insert body 70.

[0046] It will also be noted that the radial injector orifice 88 and the injector nose 16 can constitute a ball joint allowing a small angular movement between said orifice 88 and said nose 16.

[0047] In figures 1 , 2 , 5 And 6, it has been shown that the active pre-chamber ignition insert 1 according to the invention comprises at least one lateral injector well 73 arranged in the cylinder head 3 in one or more parts depending on the arrangement of the constituent material of the cylinder head 3 crossed.

[0048] Said well 73 receives the body of the injector nose 16 and, as the case may be, all or part of the other components of the injector 8, or the spark plug 12. Said well 73 connects the exterior of the cylinder head 3 - that is to say, for example, the intake ducts of the internal combustion engine 2 - with the insert well 72.

[0049] It is noted that the radial injector orifice 88 is aligned with the lateral injector well 73 so that the end of the injector nose 16 or of the spark plug 12 opens into the ignition pre-chamber 71 and / or the gas ejection duct 76 by successively passing through the lateral injector well 73 and the radial injector orifice 88.

[0050] It is noted that the cylindrical insert body 70 is deemed to be correctly indexed in rotation relative to the cylinder head 3 when the injector nose 16 is simultaneously housed in the lateral injector well 73 and in the radial injector orifice 88.

[0051] It is also noted that a seal may advantageously be provided between the lateral injector well 73 and the injector nose 16, said seal taking the form of a segment, a seal or any other means known to those skilled in the art, and said seal isolating all or part of the interior of the lateral injector well 73 from the exterior of the cylinder head 3.

[0052] It will also be noted that the lateral injector well 73 on the one hand, and the body of the injector nose 16 or any other constituent part of the injector 8 on the other hand, can constitute a ball joint connection allowing a small angular movement between said lateral well 73 and said injector 8.

[0053] We notice in figures 1 , 5 And 6 that the injector side well 73 can be housed in the casting of the cylinder head 3 at the level of the intake ports of the internal combustion engine 2. This location is slightly disruptive to the flow of gases but advantageous in terms of architecture.

[0054] In this case, the inlet of the injector side well 73 can be provided deep enough in the cylinder head so that only the body of the injector nose 16 passes through the intake ports.

[0055] In figures 1 to 5 , it has been shown that the active pre-chamber ignition insert 1 according to the invention comprises clamping means which consist of at least one insert clamping ferrule 74 which has an external ferrule thread 81 which cooperates with the internal well thread 82.

[0056] The insert clamping ferrule 74 bears directly or indirectly on a ferrule clamping face 84 presented to it by the cylindrical insert body 70 in order to directly or indirectly maintain the insert bearing surface 80 of said body 70 pressed against the insert bearing shoulder 79.

[0057] As shown by the figures 1 to 5 , the insert clamping ferrule 74 is drilled in its center to allow the spark plug 12 to pass through.

[0058] It will be noted that the insert clamping ferrule 74 can advantageously provide a key grip allowing it to be rotated for the purpose of tightening it, said key grip being able to consist of notches, orifices, or a female or male shape of any geometry whatsoever complementary to a shape presented by a tightening key.

[0059] As shown by the figures 1 to 5, the pre-chamber nose 75 can accommodate a stratification valve 13 which is pressed either against the end of the gas ejection duct 76 to close the latter in a sealed manner, or against a valve surface on the chamber side 21 to form with the gas ejection duct 76 a torch ignition pre-chamber 23 which communicates simultaneously on the one hand with the ignition pre-chamber 71 via the gas ejection duct 76, and on the other hand with the combustion chamber 5 via the gas ejection orifice 24.

[0060] As explained in patent application No. FR 3 061 743 published on July 13, 2018 belonging to the applicant, it is noted that the stratification valve 13 is pressed against the end of the gas ejection duct 76 when the pressure prevailing in the combustion chamber 5 is higher than the pressure prevailing in the ignition pre-chamber 71.

[0061] According to this particular configuration of the active pre-chamber ignition insert 1 according to the invention, a magnetic field source 44 can be positioned on the cylindrical insert body 70 to produce a magnetic field which tends to keep the stratification valve 13 pressed against the end of the gas ejection duct 76 as disclosed in patent application No. 18 58111 dated September 10, 2018 belonging to the applicant. In this case, the cylindrical insert body 70 is advantageously made in whole or in part of a magnetic material 43.

[0062] As shown by the Figure 1 to 5 , the magnetic field source 44 may take the form of a permanent magnet 53 which may not be fixed by any mechanical means to the cylindrical insert body 70 and may only remain in position on the latter due to its magnetic bonding.

[0063] Alternatively, the magnetic field source 44 may consist of a coil of conductive wire which produces a magnetic field when said wire is crossed by an electric current. This particular configuration makes it possible, for example, not to recall the stratification valve 13 pressed against the end of the gas ejection duct 76 during cold starting of the internal combustion engine 2, which makes it possible to supply the ignition pre-chamber 71 with fuel mixture not by means of the injector 8, but directly through the gas ejection orifices 24 via the gas ejection duct 76, said mixture coming from the combustion chamber 5.

[0064] As illustrated by the figures 1 to 5, the gas ejection conduit 76 may be made of a magnetic material 43 and form at the level of its contact with the stratification valve 13 a gas ejection tube 89 whose external diameter is less than that of said valve 13, said tube 89 being enclosed in a non-magnetic sleeve 85 made of a non-magnetic material 50.

[0065] The non-magnetic sleeve 85 prevents the stratification valve 13 from becoming crooked in its housing by forcing the magnetic flux produced by the magnetic field source 44 to generate field lines which are non-parallel to the stratification valve 13 at the periphery of the latter.

[0066] It is noted that the non-magnetic sleeve 85 can be mainly made of copper which has a high thermal conductivity, and be mounted tightly by shrinking around the gas ejection tube 89 to ensure maximum thermal cohesion between itself and said tube 89.

[0067] It is further noted that the stratification valve 13 may be flat to form with the end of the gas ejection duct a flat sealed contact which avoids locating said valve 13 radially unlike a conical seat.

[0068] Said flat contact also has the advantage of leaving a maximum section for the passage of gases at the same valve lift 13 when the latter is open 76, that is to say when it rests on the valve surface on the chamber side 21 with which it cooperates.

[0069] In addition, the periphery of the stratification valve 13 can advantageously be truncated and not cylindrical, which makes it possible to prevent any jamming of said valve in its housing, whatever its orientation relative to the gas ejection tube 89 with which it cooperates.

[0070] As seen in figures 1 to 5, the stratification flap 13 can be flat on both sides so that its manufacture is simplified.

[0071] As shown in figures 1 to 5 , the pre-chamber nose 75 may consist of an added nose 90 which covers the gas ejection duct 76, the gas ejection orifice 24 being arranged in said added nose 90.

[0072] It is noted that the added nose 90 allows, if necessary, the introduction of a stratification valve 13 into the pre-chamber nose 75 as provided for in patent application No. FR 3 061 743.

[0073] In the case where said valve 13 is recalled by a magnetic field source 44 as described in patent application No. 18 58111, it is possible to choose for the added nose 90 a non-magnetic material 50 such as copper which also has high thermal conductivity.

[0074] It is noted that the added nose 90 can be mounted tightly by shrinking around the gas ejection tube 89 to ensure maximum thermal cohesion between itself and said tube 89, or around said tube 89 already enclosed in a non-magnetic sleeve 85 as shown in the figures 1 , 2 , 4 And 5 .

[0075] We also notice in figures 3 And 4 that the added nose 90 may have a support collar 91 which is held tight between the insert support surface 80 and the insert support shoulder 79 when the cylindrical insert body 70 is correctly placed in the insert well 72.

[0076] According to a variant of the active pre-chamber ignition insert 1 according to the invention which is particularly understandable in figures 1 , 2 , 5 And 6, a space forming an insert cooling water chamber 86 may be left between the cylindrical insert body 70 and the insert well 72, cooling water coming for example from the cylinder head 3 being able to circulate in said water chamber 86.

[0077] We notice in figures 1 to 5 that at least one well seal 26 may be provided placed between the cylindrical insert body 70 and the insert well 72 which prevents cooling water from escaping outside the cylinder head 3 while at least one other seal prevents said water from entering the combustion chamber 5.

[0078] It is also noted that the lateral injector well 73 may consist of an openwork or non-continuous bore which communicates along its length with at least one cylinder head cooling water chamber 41 which the cylinder head 3 comprises. This particular configuration allows the insert well 72 to communicate with said water chamber 41.

[0079] In this case and as shown by the figures 1 , 2 , 5 And 6, the body of the injector nose 16 is immersed for part of its length in the cooling water contained in said water chamber 41. According to this particular variant embodiment of the ignition insert with active pre-chamber according to the invention, the diameter of the lateral injector well 73 can advantageously be provided to be significantly larger than that of the injector nose 16 which it houses so that the cooling water can pass freely around said nose 16 to enter the insert well 72 or to exit the latter.

[0080] It is noted in this respect that advantageously, the lateral injector well 73 can pass right through the insert well 72 to allow cooling water to circulate between said well 72 and at least two cylinder head cooling water chambers 41 that the cylinder head 3 comprises.

[0081] As another variant of the active pre-chamber ignition insert 1 according to the invention, particularly visible in figures 2 to 5 , the insert clamping ferrule 74 can bear on the ferrule clamping face 84 by means of a restraining spring 87, the latter guaranteeing on the one hand, an approximately constant force for maintaining the insert bearing surface 80 on the insert bearing shoulder 79 and on the other hand, a good seal between said surface 80 and said shoulder 79, in all circumstances.

[0082] It is noted that advantageously, the restraining spring 87 can take the form of at least one “Belleville” washer known per se, or at least one corrugated spring washer.

[0083] It is also noted that the restraining spring 87 can allow the internal thread of the well 82 and the external thread of the ferrule 81 to be replaced by a simple groove arranged in the insert well 72 and in which a stop ring is housed, said ring bearing on the one hand in said groove and on the other hand, on the insert clamping ferrule 74.

[0084] It will be noted that such an assembly requires a press to compress the retaining spring 87 during assembly of the retaining ring.

[0085] In Figure 5 , it has been shown that the insert bearing surface 80 can directly or indirectly form a ball joint with the insert bearing shoulder 79 while the cylindrical insert body 70 directly or indirectly forms a ball joint with the clamping means 74.

[0086] This particular configuration of the active pre-chamber ignition insert 1 according to the invention allows the cylindrical insert body 70 to freely orient itself relative to the cylinder head 2.

[0087] As shown in Figure 5 , the insert bearing surface 80 may for example be truncated in relief while the insert bearing shoulder 79 may be conical in hollow.

[0088] There Figure 5 also illustrates that the clamping means 74 can bear on the cylindrical insert body 70 by means of a sliding-swivel washer 92 which can move radially either relative to the cylindrical insert body 70 or relative to the clamping means 74.

[0089] According to a particular embodiment of the active pre-chamber ignition insert 1 according to the invention also shown in Figure 5, the sliding-swivel washer 92 can expose on the one hand, to the cylindrical insert body 70 a flat contact face, and on the other hand, to the clamping means 74 a hollow conical housing which cooperates with a raised frusto-spherical shape presented by said means 74, said conical housing and said frusto-spherical shape forming a ball joint.

[0090] As shown in Figure 5 and as an alternative embodiment of the active pre-chamber ignition insert 1 according to the invention, the sliding-swivel washer 92 can be flexible and form a restraining spring 87 which prevents the loosening of the clamping means 74 and guarantees the force of pressing the insert bearing surface 80 onto the insert bearing shoulder 79 regardless of the thermal expansion differences between the cylindrical insert body 70 and the insert well 72 which houses it.

[0091] It is noted that it is the axial compression, torsion and radial expansion of the sliding-swivel washer 92 which gives the latter the attributes of a restraining spring 87.

[0092] We will also note in Figure 5 that the pre-chamber nose 75 may comprise a pre-chamber nose seal 93 made for example of elastomer material, said seal 93 providing a seal between the combustion chamber 5 and the insert cooling water chamber 86, said seal 93 being able to be protected from the flames and hot gases present in the combustion chamber 5 by a pre-chamber nose fire segment 94.

[0093] In figures 5 And 6, it has also been shown that the injector nose 16 can be held pressed in the radial injector orifice 88 and against the cylindrical insert body 70 by elastic clamping means 95 which bear on the one hand on the injector 8, and on the other hand on the cylinder head 3.

[0094] According to this particular configuration, the end of the injector nose 16 can advantageously be frusto-spherical and rest in a conical bearing surface made in the cylindrical insert body 70, at the level of the radial injector orifice 88.

[0095] As a particular embodiment of the active pre-chamber ignition insert 1 according to the invention illustrated in figure 6 , the elastic clamping means 95 may consist of a flange 96 which bears on the injector 8 on the one hand, and which is connected to the cylinder head 3 by at least one flange screw 97 on the other hand.

[0096] On the said figure 6, it is noted that flange springs 98 can advantageously be interposed between the flange 96 and the head of the flange screws 97, said springs 98 being able to be “Belleville” washers known per se, be helical springs, or be of any type known to those skilled in the art. HOW THE INVENTION WORKS :

[0097] The operation of the active pre-chamber ignition insert 1 according to the invention is easily understood from the view of the figures 1 to 6 , which set out a non-limiting example of embodiment of the invention, other variants being possible.

[0098] As seen in figure 1 , 2 And 5 , the cylindrical insert body 70 of the active pre-chamber ignition insert 1 is mounted in the insert well 72, the latter having been provided in place of the spark plug well of the cylinder head of a conventional spark ignition engine.

[0099] Here, an insert well 72 has been produced, the diameter of which at the level of the cylindrical insert body 70 is twenty-four millimeters. It will be noted that this assembly can also be provided in place of the injector well of a conventional Diesel engine.

[0100] According to the non-limiting example set out in figures 1 to 5 , the spark plug is deliberately compact. It can, for example, be an "Iridium Performance IY24" type spark plug from the company "Denso" which has an eight millimeter diameter thread and a thirteen millimeter Allen key socket.

[0101] We notice in figures 1 to 5 that as a variant, the active pre-chamber ignition insert 1 according to the invention receives a stratification valve 13 kept pressed at rest against the end of the gas ejection duct 76 by a magnetic field produced by a magnetic field source 44.

[0102] To arrive at the assembly shown in figures 1, 2 , 4 And 5 , the cylindrical insert body 70 received a non-magnetic sleeve 85 which was shrink-fitted by temperature difference onto the gas ejection tube 89, then the assembly was topped with an added nose 90 also mounted by shrink-fitting, the stratification valve 13 having been previously introduced into said nose 90.

[0103] This done, the cylindrical insert body 70 was introduced into the insert well 72 shown in the figures 1 , 2 And 5until its insert bearing surface 80 comes into contact with the insert bearing shoulder 79 via the bearing seal 25 and, according to this non-limiting example embodiment, via a bearing collar 91 presented by the added nose 90. Then, said body 70 was rotated along its longitudinal axis until the radial injector orifice 88 which it presents is aligned with the lateral injector well 73 arranged in the cylinder head 3.

[0104] Then, the injector nose 16 was introduced into the lateral injector well 73 until said nose 16 opened into the ignition pre-chamber 71 at the desired depth.

[0105] It is noted that according to the example embodiment of the active pre-chamber ignition insert 1 according to the invention shown figures 1 to 6, the lateral injector well 73 is oriented perpendicular to the axis of the cylindrical insert body 70. This orientation is given here only as an example. Indeed, the lateral injector well 73 and the radial injector orifice 88 with which it cooperates can be freely oriented relative to the axis of the cylindrical insert body 70 so that said well 73 does not interfere or interferes as little as possible with the essential components of the cylinder head 3, and does not disturb or disturbs as little as possible the operation of said components.

[0106] Once these elements were in place, the restraining spring 87 was placed in the insert well 72 followed by the insert clamping ferrule 74, the latter having been screwed to a predetermined torque to ensure the desired contact pressure between the insert bearing surface 80 and the insert bearing shoulder 79, via the bearing seal 25 and the bearing collar 91.

[0107] We notice on the figures 1 , 2 , 5 And 6 the insert cooling water chamber 86 formed by the space left between the cylindrical insert body 70 and the insert well 72. Said chamber 86 makes it possible - according to a particular embodiment of the active pre-chamber ignition insert 1 according to the invention - to cool the cylindrical insert body 70.

[0108] Indeed, the combustion of the pilot charge 9 in the ignition pre-chamber releases heat which heats the cylindrical insert body 70. In the absence of sufficient cooling, the temperature of said body 70 could become excessive while thanks to the insert cooling water chamber 86, said temperature is maintained at an acceptable value.

[0109] Moreover, the insert cooling water chamber 86 also cools the gas ejection duct 76, the gas ejection tube 89, the non-magnetic sleeve 85, and the insert nose 90. For this purpose, the non-magnetic sleeve 85 and the insert nose 90 can advantageously be made of alloyed copper, this material offering high thermal conductivity. Thus, and thanks to said high conductivity, the heat is efficiently exported from the pre-chamber nose 75 in which the gas ejection orifices 24 are arranged to the insert cooling water chamber 86.

Claims

1. An internal combustion engine (2) comprising a cylinder head (3) which caps a cylinder (4) to form with a piston (31) a combustion chamber (5) into which a main charge (30) can be introduced, said cylinder head (3) housing an ignition prechamber (71) into which open out a spark plug (12) and an injector tip (16) of at least one injector (8) and into which a pilot charge (9) can be introduced, said prechamber (71) being able to communicate with the combustion chamber (5) successively via a gas ejection duct (76) and via at least one gas ejection orifice (24) which opens out into said chamber (5) by means of a prechamber tip (75), comprising an ignition insert (1) with active prechamber, comprising: • at least one insert well (72) provided in the cylinder head (3) and having fixing means (82), said well (72) opening out, on the one hand, to the outside of the cylinder head (3) via an insert introduction orifice (78) of large diameter, and, on the other hand, into the combustion chamber (5) via a prechamber tip orifice (77) of smaller diameter, said two diameters being connected to each other by an insert bearing shoulder (79); • at least one cylindrical insert body (70) consisting of one or more parts and in which in particular the ignition prechamber (71) and the gas ejection duct (76) are arranged, said body (70) being housed with little clearance in the insert well (72), being indexed in rotation relative to the cylinder head (3), and ending with the prechamber tip (75) which passes through the prechamber tip orifice (77), while said body (70) has an insert bearing surface (80) which bears directly or indirectly on the insert bearing shoulder (79), • at least one insert spark plug well (83) arranged in the cylindrical insert body (70), parallel to the axis of said body (70) or forming a closed angle with respect to said axis and at the centre or close to the centre of said body (70), said spark plug well (83) opening out, on the one hand, at the end of the cylindrical insert body (70) which is axially opposite the prechamber tip (75), and, on the other hand, into the ignition prechamber (71), said spark plug well (83) receiving the ignition spark plug (12) or the injector tip (16); • at least one radial injector orifice (88) arranged radially in the cylindrical insert body (70) but not necessarily perpendicular to the latter and in which the end of the injector tip (16) or the spark plug 12 is housed, said orifice (88) connecting the ignition prechamber (71) and / or the gas ejection duct (76) with the external surface of the cylindrical insert body (70); • at least one injector side well (73) provided in the cylinder head (3), said well (73) receiving the body of the injector tip (16) or the spark plug 12 and connecting the outside of the cylinder head (3) with the insert well (72) while the radial injector orifice (88) is aligned with said well (73) so that the end of the injector tip (16) or the spark plug 12 opens into the ignition prechamber (71) and / or the gas ejection duct (76) by successively passing through the injector side well (73) and the radial injector orifice (88); • clamping means (74) cooperating with the fixing means (82) in order to hold directly or indirectly the insert bearing surface (80) of the cylindrical insert body (70) pressed against the insert bearing shoulder (79); • characterised in that the prechamber tip (75) houses a lamination valve (13) which is pressed either against the end of the gas ejection duct (76) to seal the latter, or against a valve seat (21) on the chamber side to form, with the gas ejection duct (76), a torch ignition prechamber (23) which simultaneously communicates, on the one hand, with the ignition prechamber (71) via the gas ejection duct (76), and, on the other hand, with the combustion chamber (5) via the gas ejection orifice (24); • and in that it further comprises at least one magnetic field source (44) which is positioned on the cylindrical insert body (70), said source producing a magnetic field which tends to keep the lamination valve (13) pressed against the end of the gas ejection duct (76), the latter consisting of a magnetic material (43) and forming at its contact with the lamination valve (13) a gas ejection tube (89) the outer diameter of which is less than that of said valve (13), said tube (89) being enclosed in a non-magnetic sleeve (85) consisting of a non-magnetic material (50).

2. The internal combustion engine (2) according to claim 1, characterised in that the prechamber tip (75) consists of an added tip (90) which caps the gas ejection duct (76), the gas ejection orifice (24) being arranged in said added tip (90).

3. The internal combustion engine (2) according to claim 1, characterised in that a space forming an insert cooling water chamber (86) is left between the cylindrical insert body (70) and the insert well (72).

4. Internal combustion engine (2) according to claim 1, characterised in that the injector side well (73) consists of a perforated or non-continuous bore which communicates over its length with at least one cylinder head cooling water chamber (41) comprised in the cylinder head (3).

5. The internal combustion engine (2) according to claim 1, characterised in that the clamping means consist of at least one insert clamping ferrule (74) which has an outer ferrule thread (81) cooperating with the insert well fixing means (72) which consist of an inner well thread (82), said ferrule (74) being pierced in its centre to allow the spark plug (12) to pass through.

6. The internal combustion engine (2) according to claim 5, characterised in that the insert clamping ferrule (74) is supported on a ferrule clamping face (84) by means of a compression spring (87).

7. The internal combustion engine (2) according to claim 1, characterised in that the insert bearing surface (80) directly or indirectly forms a ball joint with the insert bearing shoulder (79) while the cylindrical insert body (70) directly or indirectly forms a ball joint with the clamping means (74).

8. The internal combustion engine (2) according to claim 7, characterised in that the clamping means (74) bear on the cylindrical insert body (70) by means of a sliding-swiveling washer (92) which can move radially either with respect to the cylindrical insert body (70) or with respect to the clamping means (74).

9. The internal combustion engine (2) according to claim 8, characterised in that the sliding-swiveling washer (92) is flexible and forms a compression spring (87).

10. The internal combustion engine (2) according to claim 1, characterised in that the injector tip (16) is held pressed in the radial injector orifice (88) and against the cylindrical insert body (70) by elastic clamping means (95) which bear, on the one hand, on the injector (8) and, on the other hand, on the cylinder head (3).

11. The internal combustion engine (2) according to claim 10, characterised in that the elastic clamping means (95) consist of a flange (96) which bears on the injector (8) on the one hand, and which is connected to the cylinder head (3) by at least one flange screw (97) on the other hand. 1.