HYDROGEN-POWERED INTERNAL COMBUSTION ENGINE WITH GAS TRANSFER UNIT

Description

DESCRIPTION of the industrial invention entitled: “Hydrogen-powered internal combustion engine with gas leakage transfer group” by: Stellantis Europe SpA, Italian nationality, Corso Giovanni Agnelli 200, 10135 Turin TO Designated Inventors: DI CAPRIO Francesco; ROBIGLIO Alberto; OLIVERO Oddone; D'ANNA Carmelo; GEMELLI Emilio; BONO Amos Filed on: May 31, 2024 **** DESCRIPTION TEXT Field of invention The present invention relates to engines internal combustion. The invention was developed with reference to internal combustion engines powered by hydrogen and of the spark ignition type having architecture derived from an internal combustion engine compression ignition. Known technique The current trend towards massive reduction of carbon dioxide emissions into the atmosphere invests in various levels the automotive industry supply chain and requires each of these levels to adopt solutions - a time generally not traveled - in order to return in the increasingly stringent rules both at a national level both nationally and at community level. The proposed reduction of carbon dioxide emissions carbon dioxide up to total elimination requires, among other things, to resort to self-propulsion systems that do not include combustion (such as those that equip vehicles electric), or to use fuels free of harmful substances carbon, as is the case with hydrogen. Among the salient features of combustion of hydrogen include resistance to detonation very high and a much higher flame front velocity high compared to fuel combustion containing carbon. These characteristics lead to a high pressure peak during combustion and therefore require an engine with a structure capable of resist the resulting mechanical stresses. The creation of hydrogen engines using architectures derived from diesel cycle engines, or in general compression ignition, it turns out to be particularly advantageous since these engines are generally sized to withstand stresses higher mechanical performance than the equivalent engines controlled ignition, thus allowing to maximize thermodynamic efficiency during combustion hydrogen. However, the choice to power a hydrogen engine It is not free from technical problems. Among these, a problem of primary importance concerns the accumulation of combustion gas leaks (including hydrogen unburned and related combustion products) in niches of the engine or cavities of its components, such as for example niches present in the base or cavities of the pistons, with consequent saturation and the associated risks of detonation, destructive for the engine 1. This problem is closely linked to the characteristics of hydrogen, which It is an extremely light and highly flammable gas, and to the combustion of it: all this gives rise to an accumulation of gas leaks to a much greater extent than to the accumulation that takes place in the original engine of which it is borrowed the architecture, in which the fuel is the diesel fuel. As a result, the fuel recovery circuit gas leaks – so-called blow-by circuit – results have insufficient sizing compared to the disposal needs arising from combustion of hydrogen. As is known, the blow-by circuit includes a plurality of channels obtained internally crankcase and engine head, and an adjustment of the same to changed – and in particular increased – needs in terms of gas leakage disposal It would therefore require a redesign of the entire engine. Purpose of the invention The purpose of the present invention is to resolve the previously mentioned technical issue. In particular, the purpose of the invention is to provide an internal combustion engine powered by hydrogen, which in particular borrows its architecture from a internal combustion engine with ignition compression, in which it is possible to dispose of a flow rate of gaseous leaks generated during operation of the engine without an engine redesign for to accommodate a new sizing of the blow-circuit by. Summary of the invention The purpose of the present invention is achieved by a internal combustion engine having the characteristics forming the subject of the following claims, which form an integral part of the technical teaching here administered in connection with the invention. Brief description of the figures The invention will now be described with reference to the attached figures, provided purely for illustrative purposes only limiting, and in which: - Figure 1 is a perspective view of a internal combustion according to the invention, - Figure 2 is an isolated view of an assembly of components indicated by an arrow II in figure 1, - Figure 3 is an isolated view of a component indicated by an arrow III in figure 2, and - figure 4 is a partial sectional view according to a trace IV-IV of figure 1. Detailed description The reference number 1 in figure 1 indicates in complex an internal combustion engine powered by hydrogen according to the invention. In the exemplified case, the engine 1 borrows its architecture from a known type of engine, in in particular a compression ignition engine diesel powered. The engine 1 comprises a crankcase 2 comprising a aligned arrangement of cylinders, in which the reference CY identifies a direction of alignment of the cylinders same. In a way known per se, each cylinder comprises a cylinder axis orthogonal to the CY direction along the which is a piston that moves with reciprocating motion. Always in known way, inside the base a shaft elbows are mounted rotatable around a parallel X2 axis to the CY direction. The crankshaft is not visible in figure 1, but a FW flywheel connected in rotation is visible to it at a first end of the base coinciding with a first end of the aligned arrangement of cylinders. A CL clutch is also visible for manual transmission installed on the FW flywheel. Clearly it is possible to foresee other configurations (depending on the type of transmission), such as a flex plate at the place of the FW flywheel and a torque converter instead of the CL clutch. A 4 cylinder head is arranged to fill the crankcase 2 defining with the cylinders of it respective chambers combustion. Cylinder head 4 includes an arrangement of at least one intake valve, at least one corresponding intake duct, at least one valve exhaust and at least one corresponding exhaust duct associated with each cylinder. in a way known per se, the head 4 comprises a plurality of flame plates (in generally one for each cylinder C), here preferably made recessed with respect to a surface of coupling of cylinder head 4 with crankcase 2. Each flame plate is associated with a corresponding cylinder and in correspondence with it faces – towards the cylinder itself - the corresponding arrangement of at least an intake valve, at least one corresponding intake duct, at least one exhaust valve and at least one corresponding exhaust duct. In the preferred embodiment illustrated here the head 4 has layered construction including a module of flow 5 arranged directly coupled to the base 2 and including the provision of at least one relief valve suction, at least one corresponding duct intake, at least one exhaust valve and at least one corresponding exhaust duct associated with each cylinder, and a cam module 6 arranged to surmount the flow module (which is thus in position (between the base and the cam module) and including – rotatably supported – at least one shaft camshafts for actuating the intake valves and / or of exhaust. In the preferred embodiment here illustrated head 4 is of the double camshaft type with cam-to-cam drive, and includes a camshaft suction rotating around an ICS axis of rotation (parallel to the CY direction) and configured for the actuation of the intake valves, and a crankshaft exhaust cam rotating around an axis of rotation ECS (parallel to CY direction) and configured for the operation of the exhaust valves. They are naturally possible alternative constructions – all known in themselves – in which the flow module 5 and the cam module 6 are made in one piece and / or in which in place of the cam-to-cam drive there is a wheel of timing for each camshaft. Still referring to figure 1, on one side of the head 4 (or “suction side”) oriented along the aligned arrangement of cylinders is arranged a manifold of suction 8 with inlet 10 at the which is arranged a butterfly valve, and exits corresponding to the positions of the intake ducts on flow module 5. Preferably, on the same side there is also a BS casing of a separator, particularly a gas / liquid cyclonic separator, of a engine blow-by circuit 1. In the preferred embodiment illustrated here, the intake manifold 10 is made in one piece with head 4 (with flow module 5 in the case of layered construction of the head 4), and in particular it is integrally fused with head 4 (or with module 5 in this case). On an opposite side (or “exhaust side”) of head 4, always oriented along the aligned arrangement of cylinders, an exhaust manifold is arranged (not visible, but known in itself) with corresponding entrances of the exhaust ducts and an exit at an inlet of a centripetal turbine of a supercharging group (centripetal turbine-compressor centrifugal) TC. In the preferred embodiment here illustrated the exhaust manifold is a separate element compared to head 4, and is mechanically coupled to it. According to the invention, the engine 1 comprises a gaseous leakage transfer group identified by the reference 12 and including a transfer duct 14 configured to carry a flow rate of leaks gaseous exhaust from engine 1 from an outlet made on the crankcase 2 with an inlet provided on the cylinder head 4 in position corresponding to an access hole 16 positioned in correspondence with a camshaft of the cylinder head 4 itself. The transfer duct 14 includes a 14_IN input mouth in communication with fluid with the outlet obtained on the base (2), the outlet being in turn in fluid communication with a internal volume of the said crankcase (or crankcase volume) which is located on an opposite side of the piston of each cylinder with respect to the corresponding chamber combustion, and a 14_OUT outlet in communication of fluid with the cylinder head 4 through the hole access 16 and connected to the cylinder head 4 in correspondence of the hole 16 itself. as known, the volume of crankcase 2 is in fluid communication with a engine blow-by circuit 1. In the preferred embodiment, with reference to in figure 4, the access hole 16 is arranged in position corresponding to the intake camshaft, preferably coaxial to the ICS axis. It is naturally it is possible that the entrance is achieved through an analogue access hole at the camshaft exhaust, if the head has a twin-cam configuration. For heads single-tree access is at the only tree cam. The access hole 16 in question is a hole normally present on cylinder head 4, in particular on the flow module, for axial introduction along the ICS axis of the intake camshaft in phase of engine assembly 1. So the transfer group 12 uses an access hole already present on the head cylinders 4, and normally closed with a plug. Hole 16 overlooks an environment in fluid communication with the blow-by circuit of engine 1, in particular a environment that collects a flow of gaseous leaks rising from crankcase 2 towards cylinder head 4 through the internal passages of the base 2 which create part of the blow-by circuit itself. The excess flow not disposable by the blow-by circuit is therefore disposed of by the transfer group 12, which thanks to the duct of transfer leads directly to cylinder head 4, in especially in a position close to the entry into the BS separator, the flow rate of gas leakage in question. With reference to figures 2 to 4, in a form of preferred execution the transfer group 12 comprises, in addition to the above-mentioned transfer duct 14, a collector 18 and a fluid connection 20, in which the collector 18 provides fluid communication between the inlet 14_IN of the transfer duct 14 and the outlet obtained on the base 2, and in which the fluid connection 20 It creates fluid communication between the outlet mouth 14_OUT of the transfer duct 14 and the access hole 16. The manifold 18 includes a plenum 21 in communication with fluid with a crankcase volume inside the crankcase 2, in particular a volume between the pistons and a cup of OP lubricant collection, in which it is also immersed the engine's connecting rods. It is therefore a volume into which leaks are continuously introduced gaseous during engine operation. The fluid communication between collector 18 and base 2 is made by one or more mouths of entrances 22, 24 arranged in derivation with respect to the plenum 21, and fitted into corresponding holes of the base 2 which they define the exit facing the crankcase volume. An outlet port 26 of the plenum 21 connects the plenum 21 (and the collector 18, consequently) at the mouth of 14_IN input of the transfer duct 14. The manifold 18 It therefore receives the flow of gas leaks coming out from base 2. At the opposite end of the transfer duct 14 is find the outlet 14_OUT which is in communication with fluid with the entrance defined by hole 16 by means of the fluidic connection 20. The fluidic connection 20 comprises a collar 28 which fits inside hole 16. In particular, the collar 28 fits with interference inside of hole 16 by interposing a gasket ring S28 between the outer (plus) diameter of the collar 28 and hole 16 itself, acting as a quick coupling element (the S28 gasket also acts as a sealing function fluid). The collar 28 is made in one piece with a tubular element 30 in fluid communication with the mouth 14_OUT. Preferably, the fluid communication between the tubular element 30 and the mouth 14_OUT is made by means of a tubular elbow element 32 coupled in fluid communication to the tubular element 30, and therefore connected in fluid communication with the mouth of output 14_OUT. Preferably the tubular element elbow 32 snap-fit ​​on tubular element 30 (in particular at one end opposite to the collar 28) by means of a collar 34 and an interposed annular gasket S34 between the collar 34 and an external surface of the element tubular 30. Collar 28 has a larger external diameter than an external diameter of the tubular element 30, and is shaped for this purpose so as to define a sail R which fluid-tightly occludes the circular crown between the tubular element 30 and the outer diameter (plus) of the collar 28 itself, so as to avoid fluid leaks. Yes also note that in forms of execution alternatively it is possible to omit the collector 18 and connect the 14_IN mouth to the base 2 using a fluid connection similar to connection 20, creating therefore a double quick coupling solution. Again, it is it is possible to connect the 14_IN mouth directly to the base 2, by means of a threaded fluid connection conventional installed at the mouth 14_IN itself. As already noted, thanks to the invention – particularly at transfer group 12 - it is possible to dispose of the excess flow rate that cannot be disposed of by the blow-by circuit inside the crankcase 2 and the cylinder head 4 of the engine 1 without significant changes to the engine structure 1, except for the openings on the base in correspondence of which the mouths 22, 24 (or in general the openness that establishes communication fluid between the internal environment of the base 2 and the mouth 14_IN of the transfer duct 14. Alternatively, in the preferred form of execution the object of the invention is the transfer group conveniently connected to the cylinder head with a quick-connect system provided by the fluidic fitting 20, to the full advantage of the ease of assembly already in establishment. Of course, the manufacturing details and the forms of execution may be widely varied compared to what is described and illustrated without this to go beyond the scope of the present invention as defined by the attached claims.

Claims

1. Hydrogen-fuelled spark-ignition internal combustion engine (1), comprising: - a crankcase (2) comprising an aligned arrangement (CY) of cylinders, wherein a piston is reciprocating in each cylinder along a respective cylinder axis, - a cylinder head (4) arranged to fill the crankcase (2) and defining with the cylinders thereof respective combustion chambers, wherein the cylinder head (4) comprises an arrangement of at least one intake valve, at least one corresponding intake duct, at least one exhaust valve and at least one corresponding exhaust duct associated with each cylinder, wherein the cylinder head (4) comprises at least one camshaft rotatable about a respective rotation axis (ICS, ECS) and configured to operate the at least one intake valve and / or the at least one exhaust valve of each cylinder,and wherein the cylinder head (4) comprises an access hole (16) at one end of said at least one camshaft (ICS, ECS), the internal combustion engine (1) further comprising a gaseous leak transfer assembly (12) including a transfer duct (14) having an inlet port in fluid communication with an outlet provided in said crankcase (2), the outlet being in turn in fluid communication with an internal volume of said crankcase which is located on an opposite side of the piston of each cylinder with respect to the corresponding combustion chamber, and an outlet port connected to the cylinder head at said access hole (16)., 2. Internal combustion engine (1) according to claim 1, wherein the access hole (16) is configured for installation of the camshaft in said cylinder head (4).

3. Internal combustion engine (1) according to claim 1 or claim 2, wherein the transfer assembly (12) further comprises a manifold (18) and a fluid connection (20), the manifold (18) providing fluid communication between the inlet (14_IN) of the transfer duct (14) and the outlet made on said base (2), and the fluid connection (20) providing fluid communication between the outlet port (14_OUT) of the transfer duct and the access hole (16).

4. Internal combustion engine (1) according to claim 3, wherein the manifold (18) comprises a plenum (21) in fluid communication with said internal volume of the crankcase (2) by means of one or more inlet ports (22, 24) arranged in derivation with respect to the plenum (21), the manifold (18) further comprising an outlet port (26) which connects the plenum (21) to the inlet port (14_IN) of the transfer duct (14).

5. Internal combustion engine (1) according to claim 3 or claim 4, wherein said fluid connection (20) comprises a collar (28) which fits inside said access hole (16), said collar (28) being made in one piece with a tubular element (30) in fluid communication with the outlet port (14_OUT) of the transfer duct (14).

6. Internal combustion engine (1) according to claim 5, to said tubular element (30) is - 13 coupled in fluid communication an elbow tubular element (32), the elbow tubular element (32) being connected in fluid communication with the outlet mouth (14_OUT) of the transfer duct (14).

7. Internal combustion engine according to claim 5 or claim 6, wherein said collar (28) has an external diameter greater than an external diameter of said tubular element (30), and is shaped so as to define a sail (R) which fluid-tightly occludes a circular crown included between the tubular element (30) and the external diameter of the collar (28) itself.

8. Internal combustion engine (1) according to claim 6 or claim 7, wherein said elbow tubular element (32) snaps onto said tubular element (30).

9. Internal combustion engine (1) according to claim 7 or claim 8, wherein said collar (28) fits in an interference fit inside the access hole (16) by interposing an annular gasket (S28) between the external diameter of the collar (28) and said access hole (16).

10. Internal combustion engine (1) according to any of the preceding claims, wherein said cylinder head comprises an intake camshaft and an exhaust camshaft rotatable about respective rotation axes (ICS, ECS) parallel to said aligned arrangement of cylinders (CY), wherein said access hole is located in a position corresponding to said intake camshaft, in particular in a position coaxial to the respective rotation axis (ICS).