HYDROGEN-POWERED SPARK-IGNITION INTERNAL COMBUSTION ENGINE

Description

DESCRIPTION of the industrial invention entitled: “Internal combustion engine with spark ignition and fuel supply hydrogen" by: Stellantis Europe SpA, of Italian nationality, Corso Giovanni Agnelli 200, 10135 Turin Designated Inventors: Alberto ROBIGLIO; Francesco DICAPRIO; and D'ANNA Carmelo; OLIVERO Oddone; GEMELLI Emilio. Filed on: July 23, 2024 **** DESCRIPTION TEXT Field of invention The present invention relates to internal combustion engines with hydrogen fuel. In particular, the invention was developed with reference to hydrogen-fueled internal combustion engines with ignition controlled, whose architecture is borrowed from an internal combustion engine compression ignition diesel powered. Known technique The current trend towards massive reductions in carbon dioxide emissions carbon emissions in the atmosphere affect the automotive industry at various levels and requires at each of these levels the adoption of solutions - once generally not travelled - in order to comply with the increasingly stringent rules both at the both nationally and at community level. The projected reduction of carbon dioxide emissions up to total demolition requires, among other things, the use of self-propelled vehicles which do not involve combustion (such as those fitted to electric vehicles), or to use carbon-free fuels, as is the case with hydrogen. Among the salient features of hydrogen combustion are a very high detonation resistance and a very high flame front velocity higher than the combustion of carbon-containing fuels. These characteristics lead to a high pressure peak during combustion and therefore require an engine with a structure capable of withstanding the consequent mechanical stresses. The realization of hydrogen engines using architectures derived from diesel engines, or in general compression ignition engines, are be particularly advantageous since such engines are generally sized to withstand higher mechanical stresses than the similar spark ignition engines, thus allowing maximize thermodynamic efficiency during hydrogen combustion. On the other hand, increasingly stringent regulations on emissions (for example example Nox) which must be respected during the approval of vehicles equipped with internal combustion engines increasingly carry the side effect of an increase in the size of the exhaust gas after-treatment system, and in general of the equipment of accessories and sensors on board the engine. The technical problem in question is further aggravated by the upcoming introduction of the Euro 7 standard regarding emission thresholds combustion products and acoustics. In this sense, the consequence immediate is the ever decreasing availability of space to allocate and fix the engine components, even essential ones, inside the engine compartment. Diesel engines, or compression ignition engines in general, they are typically equipped with a gas leak recovery circuit, known as blow-by gases. Such gases, which contain finely chopped oil particles nebulized, they develop inside the engine crankcase due to the imperfect seal between cylinder walls and piston rings. By means of the above circuit, which is commonly configured for the oil vapor recovery, a fluid communication is established between the crankcase and the engine intake. The circuit normally provides for the passage of exhaust gases blow-by through a separator device, configured to facilitate the condensation of suspended oil particles present in the blow-by gases, for their subsequent reintroduction into the crankcase. Via a vent, the air separated from the oil is then sent to the intake manifold, after its transit through the engine intake system air filter. Hydrogen-powered internal combustion engines generate a quantity of blow-by gas higher than that of other fuels, and particularly diesel fuel typically used in diesel engines. This phenomenon can be attributed to several factors: - properties of hydrogen: hydrogen is a light gas with small molecular size; therefore, it tends to leak more easily through spaces between the pistons and the cylinder walls; - combustion pressures: hydrogen engines operate at pressures higher combustion temperatures than diesel engines. High pressures can increase the amount of gas that leaks through the piston rings; - stoichiometric mixtures and compression ratios: hydrogen can be used with a wider range of air-fuel mixtures and variable compression ratios. These operating conditions can influence the volume of blow-by gas produced; - combustion temperatures: combustion temperatures hydrogen fuels are generally higher than diesel fuel, which can cause increased thermal expansion of engine components and affect sealing between the pistons and the cylinders. The hydrogen fueling of the engine therefore leads to the tendency to accumulate combustible vapors in the various niches normally present in the base, and also inside the pistons, with the risk of saturation of the fumes and their consequences. For this reason it is necessary to introduce fresh air into the crankcase, so as to dilute the accumulations of unburned hydrogen. At the same time, the amount of air introduced into the crankcase it transforms into a high flow of oil vapors generated from moving parts, especially the rotation of the crankshaft. This high flow of oil vapors, so-called blow-by vapors, must be expelled from the engine crankcase to avoid pressure increases resulting in leaks of the rotating sealing gaskets. Subsequently the blow-by vapours enter into a separator associated with the cylinder head where the oil is separated from the air and conveyed back into the crankcase. The air, free of oil vapors, is then conveyed into the compressor of the air supply system engine combustion. In the case of a hydrogen engine borrowed from a petrol-powered engine diesel fuel there is therefore a need to improve the efficiency of the blow-by circuit by, in particular to increase the condensation capacity of oil particles suspended in gaseous leaks, for the purpose of their subsequent re- injection into the crankcase. Furthermore, it is essential to increase the flow rate of blow-by gases to be separated to ensure efficient engine operation. However, this need clashes with the problems indicated above in in relation to the ever decreasing availability of space to allocate components of the engine, inside the engine compartment. Purpose and summary of the invention The purpose of the present invention is to solve the above mentioned problem efficiently and compatible with the high amount of blow- vapors by produced by a hydrogen-powered engine, increasing both the efficiency of oil separation, both the flow rate of blow-by vapors to be separated in an engine hydrogen-powered combustion, while minimizing fuel consumption of space. According to the present invention this object is achieved, in accordance with claim 1, thanks to the fact that the engine comprises both a blow-by circuit, which includes a blow-by separator associated with the head cylinders and including a blow-by outlet, as well as an additional blow-by separator, in where the additional blow-by separator is a dynamic cyclone separator; the engine It also includes a bracket fixed to the support body and to which it is fixed the dynamic cyclonic blow-by separator so that the blow-by separator dynamic cyclonic is arranged near the blow-by outlet of the separator blow-by associated with the cylinder head. Thanks to this solution idea it is possible to increase both the efficiency of separation of blow-by gases and their flow rate with a solution that integrates in the engine so as to minimize space consumption and the addition of additional components. In one embodiment of the engine according to the invention, the bracket dynamic cyclonic blow-by separator support includes a flat base for attachment to the engine support body having at least one hole for passage of at least one threaded fastening means engaged within a threaded stud of the support body, and a post protruding vertically from the attachment base for fixing the dynamic cyclonic blow-by separator. In one embodiment the dynamic cyclonic blow-by separator comprises a cylindrical body comprising a base and a lid, and two pairs of opposite tangential cylindrical compasses, obtained perpendicularly to the casing, for the passage of respective threaded fastening means, and the upright of the support bracket includes two pairs of studs or threaded holes for the use of threaded fastening means for fixing the additional separator to the stirrup. In a further embodiment according to the invention, the upright of the support bracket includes a pair of holes for the passage of respective threaded fastening means engaged within a pair of already threaded studs present in the support body. In a further embodiment the support bracket comprises a reinforcing rib extending from the flat base to the upper end of the upright between the pairs of threaded holes. In a further embodiment the cyclonic blow-by separator dynamic includes: a connector for a blow-by gas inlet pipe arranged in a lower portion of the cylindrical body, in which the blow-by gas inlet tube is in fluid communication with the blow-by outlet of the associated blow-by separator to the cylinder head, a connector for an air outlet tube arranged in a portion top of the cylindrical body in which the air outlet pipe tube is in fluid communication with the air supply system compressor combustion located on the cylinder head of the engine, and a connector for an oil drain pipe arranged in the lower base of the cylindrical body, in which the oil drain pipe is in fluid communication with the base. Brief description of the drawings The invention will now be described in detail with reference to the drawings. annexes, provided purely by way of non-limiting example, in which: - Figure 1 is a schematic perspective view of part of an engine with hydrogen fuel according to the invention comprising a head cylinders; - Figure 2 is a schematic perspective view of part of the head engine cylinders in figure 1; - Figure 3 is a larger-scale schematic perspective view of a detail of figure 2 seen from a different angle; - Figure 4 is a perspective view of the separator support bracket cyclonic blow-by of the engine according to the invention; and - Figure 5 is a larger-scale schematic perspective view of the Figure 1 with the cyclonic blow-by separator removed from the support bracket. Detailed description of the invention Referring to figure 1, 1 generally indicates the upper part of an internal combustion engine powered by hydrogen, borrowed from a compression ignition internal combustion engine powered by diesel fuel. The engine 1 comprises in a manner known per se a crankcase B which includes an aligned arrangement of cylinders and a crankshaft at one end of which a drive pulley or gear wheel, not illustrated, is fitted. Even in a way known in itself, the engine 1 is provided with a top a 2 cylinder head, two enlargements of which are visible in figures 2 and 3, which encloses an arrangement of intake valves, intake ducts, exhaust valves and exhaust pipes associated with each cylinder. Engine 1 known to include a combustion air supply system which includes a compressor 3 and a throttle body 4. The head 2 includes a support body 5 in which, in a manner known per se, two distribution shafts are mounted side by side in a rotating manner, not visible in the drawings, one of which is driven in rotation by the crankshaft of engine 1, through a pulley, and in turn controls the rotation of the other shaft distribution by means of a pair of gear wheels, not visible, arranged inside the head 2. The two distribution shafts are designed to control in opening and closing the intake and exhaust valves of engine 1 in such a way conventional. Head 2 also includes a first blow-by separator 6 which comprises a blow-by output 7 visible in figure 2. Since, as mentioned, the blow-by flow rate of the hydrogen engine 1 is greater than that of the diesel engine from which it is derived, the outgoing gas from the first separator 6 still has a significant amount of oil that has not been separate. According to the peculiar feature of the invention, the engine internal combustion 1 powered by hydrogen according to the invention comprises an additional or second blow-by separator 8, in particular a blow-by separator by dynamic cyclonic 8 which includes a cylindrical casing 9 including, in a manner conventional, a plurality of rotating blades and provided with a base 15 and a cover 21. This blow-by separator 8 is fixed to a bracket 10 coupled on the support body 5 of engine 1 and which will be discussed. The mating position of the bracket 10 on the support body 5 of the engine 1 and its conformation are such that the second blow-by separator 8 is arranged in proximity to the blow-by outlet 7 of the first blow-by separator 6. A further aim of the invention is in fact to reduce as much as possible the connection distance between the first 6 and the second 8 blow-by separator, so as to to create a flow as direct as possible from one to the other by increasing overall efficiency. Conveniently according to the invention, the additional blow-by separator 8 It is a dynamic cyclonic separator that uses centrifugal force to separate the residual oil particles from the blow-by gas flow escaping from the first separator 6. Referring to figure 2, the blow by gases exiting the first blow-by separator 6 are conveyed inside the second separator 8 through an inlet pipe 11 and the inlet connector 12 arranged in a lower portion of the cylindrical casing 9 of the separator 8, where such gases are rotated inside a cylindrical chamber inside the separator 8. This cyclonic movement creates a centrifugal force that pushes the oil particles towards the walls of the separator 8. The separated oil then slides onto the bottom of the separator 8 where it is channeled into an oil outlet connector 13 arranged on the base 15 of the separator 8 and, subsequently, in a tube 14 for the oil outlet. This oil outlet pipe 14 is in fluid communication with the crankcase B so that the separated oil can return to the engine 1. The purified gases, free of most of the oil particles, are expelled from the separator by means of an air outlet tube 16 which is connected, at one end to a connector 17 arranged in an upper portion of the cylindrical casing 9 of the separator 8, and at the other end to the compressor 3 of the combustion air supply system to the engine 1. The dynamic cyclonic blow-by separator 8 offers numerous advantages, among which such as a high efficiency of separation of oil particles, obtained thanks to the centrifugal force, and a high flow rate of gases to be separated. This allows manage the increased production of blow by gases in the hydrogen engine 1 compared to to the diesel engine from which it is derived. Referring to figures 3,4,5, the support bracket 10 of the dynamic cyclonic blow-by separator 8 includes a flat attachment base 18 to the support body 5 of the engine 1 comprising a protruding ear 28 provided with a hole 19, visible in figure 4, for the passage of a means of threaded fixing 20 engaged within a threaded stud provided on the body of engine support 5 1. Perpendicular to one end of the base 15 of the support bracket 10 extends a vertical upright 22 which includes two pairs of studs threaded 23, for the engagement of threaded fastening means 24 for the fastening of the dynamic cyclonic blow-by separator 8 to bracket 10. The vertical upright 22 It also includes a lower appendage 26, protruding from the side of the ear 28 of the flat base 18, on which a pair of holes 25 is obtained, visible in the figure 4, for the passage of respective threaded fastening means 27 engaged within a pair of threaded studs of the support body 5. As visible in figures 1 and 3, tangentially and perpendicularly to the cylindrical casing 9 of the dynamic cyclonic blow-by separator 8, are form two pairs of cylindrical compasses 29 aligned and opposite for the passage of the threaded fastening means 24 of the blow-by separator 8 for its fastening to the upright 22 of the support bracket 10. With reference to figures 3 and 4, the support bracket 10 also comprises a tapered reinforcing rib 30 extending from the flat base 18 at the upper end of the upright 22 between the pairs of threaded studs 23. Thanks to the arrangement described above, the placement of the separator dynamic cyclonic 8 according to the invention is located on the support body 5 of engine 1, near the blow-by separator 6 associated with the cylinder head 2, advantageously solving the problem of its positioning in other areas no longer available as they are occupied by other auxiliary equipment of the motor 1 or too far from output 7 of the first separator 6. Naturally the construction details and the forms of implementation may vary widely from those described and illustrated, without thereby departing from the scope of the present invention.

Claims

CLAIMS 1. A hydrogen-fuelled spark-ignition internal combustion engine (1), comprising: a crankcase (B), with an aligned arrangement of cylinders, and a cylinder head (2) arranged to fill said crankcase (B), and including: a support body (5) for at least one camshaft, a combustion air supply system comprising a compressor (3) and a throttle body (4), wherein the engine (1) comprises a blow-by circuit, which includes a blow-by separator (6) associated with the cylinder head (2) and comprising a blow-by outlet (7), characterised in that it comprises a further blow-by separator (8), said further blow-by separator (8) being a dynamic cyclonic separator,and from the fact that the engine (1) comprises a support bracket (10) fixed to said support body (5) and to which said dynamic cyclonic blow-by separator (8) is fixed wherein said dynamic cyclonic blow-by separator (8) is arranged in proximity to said blow-by outlet (7) of said blow-by separator (6) associated with the cylinder head (2)., 2. Engine (1) according to claim 1, characterised in that said support bracket (10) of the dynamic cyclonic blow-by separator (8) comprises a flat base (18) for attachment to the support body (5) of the engine (1), said flat base (18) including a protruding ear (28) on which at least one hole (19) is made for the passage of a threaded fastening means (20) engaged within a threaded boss of said support body (5) and an upright (22) protruding vertically from the base (18) for the fixing of said dynamic cyclonic blow-by separator (8).

3. Engine (1) according to claim 1 or 2, characterised in that said dynamic cyclonic blow-by separator (8) comprises a cylindrical casing (9) including a base (15) and a cover (21), in which tangentially to said cylindrical casing (9) are formed two pairs of cylindrical bushings (29) - 10 - aligned and opposite for the passage of respective threaded fixing means (24), and in that said vertical upright (22) of said support bracket (10) comprises two pairs of threaded studs (23) for the engagement of said threaded fixing means (24).

4. Engine (1) according to claim 2 or 3, characterised in that said vertical upright (22) of said support bracket (10) comprises a lower appendage (26), protruding from the side of said ear (28) of the flat base (18), on which a pair of holes (25) is obtained for the passage of respective threaded fastening means (27) engaged within a pair of threaded studs of said support body (5).

5. Engine (1) according to one of the preceding claims, characterised in that said support bracket (10) comprises a tapered reinforcing rib (30) extending from said flat base (18) to the upper end of said upright (22) between said pairs of threaded studs (23).

6. Engine (1) according to one of the preceding claims, characterised in that said dynamic cyclonic blow-by separator (8) comprises: an inlet connector (12) for a pipe (11) for the inlet of blow-by gases arranged in a lower portion of said cylindrical casing (9), wherein said pipe (11) for the inlet of blow-by gases into said cyclonic separator (8) is in fluid communication with said blow-by outlet (7) of the blow-by separator (6) associated with the cylinder head (2), a connector (17) for a pipe (16) for the air outlet arranged in an upper portion of said cylindrical casing (9), wherein said pipe (16) for the air outlet from said cyclonic separator (8) is in fluid communication with said compressor (3) of the combustion air supply system of the engine (1), and an oil outlet connector (13) for a pipe (14) for the oil outlet arranged in said base (15). of the cylindrical casing (9),wherein said oil outlet tube (14) is in fluid communication with said crankcase (B).,