Drive unit with a turbocharged combustion engine and an electrical energy recovery system

Abstract

Drive unit (1) with: a turbocharged internal combustion engine (2) with: a longitudinally oriented crankshaft (6), a crankcase (3), a plurality of cylinders (4) arranged in a "V" shape with an angle of 90° between the two cylinder banks of the cylinders (4), two cylinder heads (7) coupled to the crankcase (3) and forming the roof of the cylinders (4), a plurality of pistons (5), an intake system (12) comprising a main intake line (21) and two intake manifolds (33), each coupled to a cylinder bank of the cylinders (4), an exhaust system (13) with an exhaust pipe (19), and a turbocharger (17) having a turbine (18) arranged along the exhaust pipe (19) and a compressor (20) arranged along the main intake line (21); a system (27) for storing electrical energy; a first reversible electric machine (25) which is mechanically connected to the crankshaft (6) via a gear transmission; a first controller (26) configured to control the first electric machine (25) and coupled to the storage system (27); a second reversible electric machine (28) mechanically coupled to the turbocharger (17); a second controller (29) configured to control the second electric machine (28) and coupled to the storage system (27), and a control unit (54); wherein each cylinder (4) comprises a fuel injection system (15) which cyclically injects the fuel directly into the cylinder (4) and a spark plug (16); wherein the turbocharger (17) comprises a single shaft (39) which is oriented longitudinally like the crankshaft (6) and connects the turbine (18), the compressor (20) and the second electric machine (28) to one another; Drive unit (1) characterized in that: the second electric machine (28) is arranged next to the compressor (20) on the side opposite the turbine (18); an air inlet pipe (42) is provided which has an inlet opening which receives the air from an air inlet (31) and is arranged radially to the axis of rotation of the compressor (20) and has an outlet opening which is aligned axially to the axis of rotation of the compressor (20) and is coupled to an inlet of the compressor (20); an end piece of the inlet pipe (42) has the shape of a ring which comprises and surrounds a part of the second electrical machine (28) such that the electrical machine (28) is located centrally in the inlet pipe (42) and is pneumatically isolated from the interior of the inlet pipe (42); the compressor (20) and the second electric machine (28) are arranged between the cylinder banks; the turbine (18) is arranged on the outside of the cylinder banks, offset longitudinally relative to the crankcase (3); and the two intake manifolds (33) are arranged above the compressor (20) and above the second electric machine (28).

Description

TECHNICAL AREA

[0001] The present invention relates to a drive unit with a turbocharged internal combustion engine and an electrical system for energy recovery. STATE OF THE ART

[0002] Currently, Formula 1 vehicles use a power unit with a turbocharged internal combustion engine with six cylinders arranged in a V shape in two cylinder banks of three cylinders each.

[0003] In addition, the drive unit includes an electrical system with a first electrical machine (called "MGU-K" ie "Motor Generator Unit, Kinetic"), which is mechanically connected to the crankshaft and is used as a generator for generating electrical energy when the vehicle is to be braked, or as a motor to increase the torque acting on the crankshaft. The electrical system also includes a second electrical machine (called "MGU-H" ie "Motor Generator Unit, Heat"), which is mechanically connected to the turbocharger and, by utilizing the kinetic energy of the exhaust gases, is used as a generator for generating electrical energy or as a drive for accelerating the response of the turbocharger at the beginning of an acceleration phase (ieto help the compressor return to optimal speed when the driver demands power from the combustion engine, minimizing turbocharger lag and maximizing performance).

[0004] In Formula 1 racing, there is an operational limit on the fuel flow that can be introduced into the combustion engine, which effectively limits the chemical energy introduced for the same fuel specification. DESCRIPTION OF THE INVENTION

[0005] The aim of the present invention is to provide a drive unit with a turbocharged internal combustion engine and an electrical energy recovery system, with which extremely high performance can be achieved in conjunction with high energy efficiency (i.e. reduced fuel consumption).

[0006] According to the invention, a drive unit with a turbocharged internal combustion engine and an electrical energy recovery system is provided according to the appended claims.

[0007] The claims describe preferred embodiments of the present invention and are part of this description. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] The present invention will now be described with reference to the accompanying drawings, which more or less schematically and demonstratively represent a non-limiting embodiment; in which: • Fig. 1 a schematic view of a drive unit according to the invention with a turbocharged internal combustion engine and an electrical system for energy recovery; • Fig. 2-5 different views of the drive unit from Fig. 1, where parts have been omitted and simplified for clarity; • Fig. 6 a schematic view of a cylinder of the turbocharged internal combustion engine of the drive unit of Fig. 1; • Fig. 7 a plan view and with parts omitted for clarity of a top land of the cylinder of Fig. 6; • Fig. 8 a sectional drawing along the line VIII-VIII of the top land from Fig. 7; • Fig. 9 a schematic view in section of a cylinder head from Fig. 6; • Fig. 10 is a schematic and enlarged view of a pre-chamber of the cylinder head of Fig. 6; • Fig. 11 a perspective view of an end piece of an intake system of the turbocharged internal combustion engine of the drive unit of Fig. 1; • Fig. 12 and Fig. 13 Two perspective views with parts removed for clarity and in two different working configurations of the intake system from Fig. 11; • Fig. 14 a schematic view of a turbocharger and an associated electric machine of the turbocharged internal combustion engine of the drive unit from Fig. 1; • Fig. 15 and Fig. 16 two different views with parts of the turbocharger omitted for clarity Fig. 14; • Fig. 17 a schematic view of a power storage system of the drive unit from Fig. 1; and • Fig. 18 a schematic view of a control of an electric machine of the drive unit from Fig. 1. PREFERRED EMBODIMENTS OF THE INVENTION

[0009] In the Fig. 1-5, 1 designates a drive unit with a turbocharged four-stroke internal combustion engine 2.

[0010] As is clearer in Fig. 6, the internal combustion engine 2 comprises a crankcase 3 in which several cylinders 4 are formed (in Fig. 2 only one of them is shown); in detail, there are six cylinders 4 "V" shaped and with an angle of 90° between the two cylinder banks of the cylinders 4. Each cylinder 4 has a combustion chamber and a corresponding piston 5, which is mechanically connected to a crankshaft 6 in order to transmit the power generated by combustion to the crankshaft 6. Coupled (connected) to the crankcase 3 are two cylinder heads 7, which represent the headliner of the cylinders 4 (i.e. the upper end of the cylinders 4 with the so-called "fire land").

[0011] The internal combustion engine 2 is configured to be arranged longitudinally (aligned), i.e., the crankshaft 6 is arranged longitudinally (aligned). Furthermore, the internal combustion engine 2 is configured to be arranged centrally, i.e., the internal combustion engine 2 is arranged behind the cockpit and located between the front and rear wheels.

[0012] Each cylinder 4 includes two intake valves 8 controlled by a camshaft 9 driven by the crankshaft 6. In addition, each cylinder 4 includes two exhaust valves 10 controlled by a camshaft 11 driven by the crankshaft 6.

[0013] The internal combustion engine 2 comprises an intake system 12 that draws in outside air and directs it into the cylinders 4 (the air intake into the cylinders 4 is controlled by the intake valves 8). The internal combustion engine 2 comprises an exhaust system 13 that discharges the exhaust gases from the cylinders 4 to the outside.

[0014] Each piston 5 is mechanically connected to the crankshaft 6 via a corresponding connecting rod 14 so that the force generated by combustion is transmitted to the crankshaft 6.

[0015] Each cylinder 4 includes a fuel injector 15 that cyclically injects fuel directly into the cylinder 4 and is located centrally between the two exhaust valves 10. Each cylinder 4 also includes a spark plug 16 that is cyclically actuated to ignite the air (oxidizer)-fuel mixture in the combustion chamber after the compression phase.

[0016] According to the presentation in Fig. 1, the internal combustion engine 2 comprises a supercharging system with a single turbocharger 17, which includes a turbine 18 arranged along an exhaust pipe 19 and receives the exhaust gases from both cylinder banks of the cylinders 4 to rotate at high speed under the pressure of the exhaust gases expelled from the cylinders 4, and a compressor 20 arranged along a main intake line 21 to increase the air pressure (the overpressure generated by the compressor 20 can reach 5-6 bar and more). A single intercooler 22 (common to both cylinder banks of the cylinders 4) is arranged along the main intake line 21 and downstream of the compressor 20.

[0017] According to the presentation in Fig. 1, the crankshaft 6 of the internal combustion engine 2 is cascaded to a gearbox 23 arranged longitudinally and from which two drive shafts extend, which are connected to the two rear drive wheels 24.

[0018] The drive unit 1 comprises a reversible electric machine 25 (i.e., it can operate both as an electric motor by absorbing electrical energy and generating mechanical drive torque, and as a power generator by absorbing mechanical energy and generating electrical energy) and is mechanically connected to the crankshaft 6 via a gear transmission, which includes, among other things, a planetary gear. The electric machine 25 can be operated as an electric motor to provide additional drive torque for the crankshaft 6, or as a power generator for regenerative braking by absorbing mechanical energy (i.e., the vehicle's kinetic energy) to generate electrical energy. The electric machine 25 is controlled by a control device 26 (in particular, an electronic AC / DC converter, i.e., an "inverter") coupled to an electrochemical energy storage device 27 with batteries.In this application, the control device 26 is bidirectional and includes a DC side connected to the storage system 27 and a three-phase AC side connected to the electric machine 25.

[0019] The drive unit 1 comprises a reversible electric machine 28 (i.e., it can operate both as an electric motor by absorbing electrical energy and generating mechanical drive torque, and as a power generator by absorbing mechanical energy and generating electrical energy) and is mechanically connected to the turbocharger 17. The electric machine 28 can operate as an electric motor to generate drive torque that accelerates the compressor 20 to increase the rotational speed of the compressor 20 more quickly, or it can operate as a power generator to utilize the energy of the exhaust gases, which rotate the turbine 18 to generate electricity. The electric machine 28 is controlled by a control device 29 (specifically, an electronic AC / DC converter, i.e., an "inverter") coupled to the power storage system 27.In this application, the control device 29 is bidirectional and includes a DC side connected to the storage system 27 and a three-phase AC side coupled to the electric machine 28.

[0020] Preferably, the two control devices 26 and 29 are arranged side by side and are part of one and the same electrical system in a single common housing (shown in the Fig. 2-5), which is suitably electrically insulated and also contains the storage system 27, and is arranged longitudinally in front of the internal combustion engine 2 (i.e., it is substantially arranged under the cockpit so that it is protected by the safety cockpit).

[0021] The intake system 12 comprises a single air inlet 31 (shown more clearly in the Fig. 2, Fig. 3 and Fig. 5), which draws in the air from the environment and directs it to the main intake line 21. As previously stated, the main intake line 21 passes through the compressor 20 of the turbocharger 17 and then through the charge air cooler 22. As shown in the Fig. 11, Fig. 12 and Fig. 13, the main intake line 21 divides directly behind the charge air cooler 22 into six end intake lines 32, each of which originates from the main intake line 21 and ends in a corresponding cylinder 4. In detail, two intake manifolds 33 are provided, each of which is assigned to a corresponding cylinder bank of the cylinders 4 and is arranged along the three end intake lines 32 of a cylinder bank of the cylinders 4; ie the three end intake lines 32 of a cylinder bank of the cylinders 4 end at the inlet of the corresponding intake manifold 33 and continue at the outlet of the corresponding intake manifold 33.

[0022] According to a preferred embodiment, the three final intake lines 32 of a cylinder bank of cylinders 4 are housed in a common pipe 34 upstream of the respective intake manifold 33, while they are divided into separate runs downstream of the corresponding intake manifold 33. Specifically, each common pipe 34 has sections inside that keep the corresponding three final intake lines 32 pneumatically separated from one another.

[0023] According to the presentation in the Fig. 12 and Fig. 13, inside each intake manifold 33, there are three variable-length intake trumpets 35 that can change their length by means of a telescopic mechanism controlled by a hydraulic actuator. Each intake trumpet 35 has an outlet whose position is fixed and from which a corresponding final intake duct 32 extends, and an inlet that can change its position axially, approaching the outlet as the intake trumpet 35 shortens and moving away from the outlet as the intake trumpet 35 lengthens.

[0024] The inlet trumpets 35 can vary their length between one (in Fig. 12) minimum length at which the internal volume of the intake manifold 33, in which the air of the final intake lines 32 mixes, is the largest, and a (in Fig. 13) maximum length at which the internal volume of the intake manifold 33, in which the air of the final intake ducts 32 mixes, becomes zero; ie when an intake trumpet 35 (in Fig. 13), it seamlessly connects the corresponding final intake line 32 from the inlet of the intake manifold 33 to the outlet of the intake manifold 33, bypassing the intake manifold 33.

[0025] According to the presentation in Fig. 1, the exhaust system 13 comprises two exhaust manifolds 36 which converge in the exhaust pipe 19 and receive the exhaust gases from the corresponding cylinders 4 to which they are individually connected; more specifically, each exhaust manifold 36 is connected to three cylinders 4 via corresponding ducts which originate from the three cylinders 4 and terminate at an inlet of the exhaust manifold 36 (viewed differently, each exhaust manifold 36 is initially divided into three to connect to the corresponding three cylinders 4).

[0026] According to a preferred embodiment, the exhaust manifolds 36 and the exhaust pipe 19 upstream of the turbine 18 are externally insulated by means of a heat-insulating material secured around the exhaust manifolds 36 and the exhaust pipe 19; as a result, the exhaust gases emerging from the cylinders 4 at temperatures above 700°C cool down less as they flow towards the turbine 18 and thus reach the turbine 18 hotter (i.e. with a higher enthalpy which, other factors being equal, makes it possible to generate more electrical energy via the electric machine 28).

[0027] Thanks to the intake trumpet 35, the final intake ducts 32 have a variable length, becoming longer or shorter depending on the speed of the crankshaft 6. When the intake valves 8 are open and air is sucked in, the air flows quickly through the corresponding final intake duct 32, while the air remaining in the final intake duct 32 upon sudden closure of the intake valves 8 stagnates and accumulates, forming a high-pressure area and consequently generating a high-pressure wave that travels back along the corresponding final intake duct 32, moving away from cylinder 4. When the pressure wave reaches the end of the corresponding final intake duct 32, it reverses and travels back along the corresponding final intake duct 32 as a vacuum wave (this phenomenon can occur several times per combustion cycle).It must be taken into account that the pressure wave moves at a constant speed, while the time interval between one and the next opening of the intake valves 8 varies depending on the speed of the crankshaft 6; consequently, when the speed of the crankshaft 6 changes, the synchronism between the pressure wave and the opening of the intake valves 8 changes. By appropriately dimensioning the system and adopting a suitable movement strategy for the intake trumpets 35, these dynamic phenomena of the intake air can be utilized to optimize the operation of the internal combustion engine 2 over a wide speed range.

[0028] In particular, thanks to the fact that the final intake ducts 32 start immediately downstream of the charge air cooler 22 as a result of the internal division of the common pipes 34 into three pneumatically separated chambers (corresponding to the three respective final intake ducts 32), the length of the final intake ducts 32 can be varied within a wide range (within a length range of more than 600 mm) and in this way an optimal filling of the cylinders 4 can be achieved in all speed ranges in order to achieve the greatest possible power under all conditions.

[0029] In detail, the inlet trumpets 35 in the position of (in Fig. 13) completely cover the three end intake lines 32 of an intake manifold 3 and thereby prevent the pressure waves in one end intake line 32 from negatively influencing the pressure waves in the other two end intake lines 32.

[0030] According to the presentation in Fig. 14, in the turbocharger 17, the wheel 37 of the turbine 18 and the wheel 38 of the compressor 20 are mounted on a common shaft 39. In addition, the electric machine 28 is connected to the shaft 39 (consequently, the rotor of the electric machine 28 is fixedly connected to the shaft 39) and is arranged next to the compressor 20 on the side opposite the turbine 18, i.e. the compressor 20 is located between the electric machine 28 and the turbine 18. As a result, the electric machine 28 is arranged close to the compressor 20 (which represents the "cold side" of the turbocharger 17) and thus further away from the turbine 18 (which represents the "hot side" of the turbocharger 17).

[0031] A bypass line 40 is provided along the exhaust pipe 19, which is connected in parallel to the turbine 18 such that its ends are connected upstream and downstream of the turbine 18. An electronically controlled wastegate valve 40 is arranged along this bypass line, which can regulate the exhaust gas flow through the bypass line and is controlled by an actuator (specifically, a hydraulic proportional actuator). A bypass line 21 is provided along the main intake line 21, which is connected in parallel to the compressor 20 such that its ends are connected upstream and downstream of the compressor 20. An electronically controlled pop-off valve 41 is arranged along this bypass line, which can regulate the flow of exhaust gases flowing through the bypass line and is controlled by an actuator (specifically, a hydraulic proportional actuator).According to one possible embodiment, the bypass line of the pop-off valve 41 is connected in parallel not only to the compressor 20 but also to the charge air cooler 22, i.e. it starts upstream of the compressor 20 and ends downstream of the charge air cooler 22.

[0032] According to a study published in Fig. 15 and Fig. 16, an air inlet pipe 42 is provided which has an inlet opening (to which the main intake line 21 coming from the air inlet 31 is connected) which is aligned radially with the axis of rotation of the compressor 20 and has an outlet opening which is aligned axially with the axis of rotation of the compressor 20 and is arranged at an axial air inlet into the compressor 20 (i.e. it opens into the inlet of the compressor 20). In detail, an end piece of the inlet pipe 42 has the shape of a ring which encloses and surrounds part of the electric machine 28 (and as a result, the air flowing in the end piece of the inlet pipe 42 flows around the electric machine 28, since the end piece of the inlet pipe 42 encloses the electric machine 28). That is to say.that, taking into account a further aspect, the electric machine 28 is located partially in the middle of the air inlet pipe 42 (but not within it), the end of which is annular, and that the air thus flows at least partially around the electric machine 28 (being, of course, separated from the electric machine 28 by the walls of the inlet pipe 42). That is, the electric machine 28 remains pneumatically separated from the interior of the inlet pipe 42. This arrangement of the inlet pipe 42 relative to the electric machine 28 is particularly advantageous since it allows for an optimization of the arrangement and thus enables a significant saving of space in the axial direction (i.e., overall, the complex of turbocharger 17 and electric machine 28 is axially shorter); moreover, this arrangement of the inlet pipe 42 relative to the electric machine 28 also allows for an improvement (or at least no disadvantage) in the cooling of the electric machine 28.

[0033] According to a preferred embodiment, the shaft 39 of the turbocharger is oriented longitudinally (hence parallel to the crankshaft 6), the compressor 20 is arranged in the middle of the cylinder banks (ie in the area delimited laterally by the two cylinder banks arranged in a "V" shape), the turbine 18 is arranged externally on the cylinder banks (ie outside the area delimited as in the Fig. 2-5 is laterally delimited by the two "V"-shaped cylinder banks), and the electric machine 28 is arranged in the middle of the cylinder banks (i.e. in the area that is laterally delimited by the two "V"-shaped cylinder banks). In detail, the turbine 18 is arranged longitudinally behind the crankcase 3, i.e. offset longitudinally with respect to the crankcase 3. Preferably, the two intake manifolds 33 are arranged above the compressor 20 and above the electric machine 28; i.e. the compressor 20 and the electric machine 28 are arranged in an area that is delimited below by the crankcase 3, laterally by the cylinder banks, and above by the two intake manifolds 33. The charge air cooler 22 is arranged longitudinally in front of the crankcase 3, i.e. offset longitudinally with respect to the crankcase 3 and on the side opposite the crankcase 3 with respect to the turbine 18 (i.e.the crankcase 3 is located between the charge air cooler 22, which is located in front of the crankcase 3, and the turbine 18, which is located behind the crankcase 3).

[0034] It is important to note that the final intake lines 32 are located on the sides of the electric machine 28, i.e., the corresponding three final intake lines 32 are located between the electric machine 28 and the cylinders 4 of a cylinder bank. Consequently, the electric machine 28 is located in an area that is delimited at the top by the intake manifolds 33 and laterally by the final intake lines 32; i.e., the electric machine 28 is "surrounded" by components (lines) of the intake system 12. This arrangement enables optimization (reduction) of the space requirement and does not impair the cooling of the electric machine 28.

[0035] The above-described arrangement of the turbocharger 17 and the intake manifold 33 offers various advantages and was designed to optimize the overall layout of the power unit 1 and its installation in the vehicle. Among other things, the above-described arrangement of the turbocharger 17 and the intake manifold 33 enables a lower center of gravity (the electrically controlled turbocharger 17 is much heavier than the intake manifold 33) and also optimizes the intake air flow by minimizing load losses in the intake system 12.

[0036] According to the more detailed description in the Fig. 7-10, the corresponding cylinder head 7 comprises, for each cylinder 4, a prechamber 43 arranged centrally relative to the combustion chamber, located in the area laterally delimited by the intake valves 8 and the exhaust valves 10, and having a longitudinal axis parallel to a longitudinal axis of the cylinder 4. Each prechamber 43 is passive and contains only the corresponding spark plug 16; consequently, the single fuel injection valve 15 of each cylinder 4 is arranged outside the prechamber 43 between the two exhaust valves 10.

[0037] Each pre-chamber 43 has a series of small calibrated holes 44 (see in more detail in Fig. 10), which are realized at the level of a nose of the pre-chamber 43 and connect the pre-chamber 43 to the combustion chamber of the respective cylinder 4. During operation of the internal combustion engine 2, each pre-chamber 43 fills with a portion of the mixture of the respective cylinder 4, which enters the pre-chamber 43 via the bores 44; the spark that forms between the electrodes of the spark plug 16 generates a flame in a smaller space, which quickly propagates into the combustion chamber via the bores 44 in order to quickly ignite the air-fuel charge present in the combustion chamber.

[0038] According to a Fig. 10, each pre-chamber 43 comprises at least six holes 44 and generally fewer than fifteen holes 44: increasing the number of holes 44 increases the flame bursts that spread in the combustion chamber, but too high a number of holes 44 excessively reduces the power of the individual flame bursts, which then do not reach all areas of the combustion chamber and accelerate combustion as a whole.

[0039] According to a Fig. 10, the ratio between a length L and a diameter D of each bore 44 is greater than 0.5 and preferably greater than 1 (ie, preferably each bore 44 is longer than wide).

[0040] According to a Fig. In the preferred embodiment shown in Figure 10, the internal volume of each pre-chamber 43 is greater than 0.05% and preferably greater than 0.1% of the displacement of the corresponding cylinder 4. Specifically, the internal volume of each pre-chamber 43 is between 0.05% (preferably 0.1%) and 1% of the displacement of the corresponding cylinder 4.

[0041] According to a preferred embodiment, a combination of materials is used in the manufacture of the pre-chamber 43, for example two different metal alloys, in order to guarantee both an adequate heat exchange between the walls of the cylinder head 7 and sufficient resistance to the high temperatures occurring.

[0042] In the four-stroke internal combustion engine 2, combustion occurs in the first part of the third stroke of each piston 5: after the air is sucked in during the initial downward movement to bottom dead center, the piston 5 compresses it by moving to top dead center; after the fuel is injected, a flammable mixture forms, which is ignited and generates a flame capable of releasing the energy necessary to push the piston 5 downwards again. The final and fourth stroke, with the exhaust valves 10 open, serves to expel the exhaust gases from the combustion chamber to prepare the volume for a new cycle.

[0043] The combustion process of the atomized fuel-air mixture is ignited by an electrical discharge generated by each spark plug 16. On the other hand, when combustion is initiated spontaneously in an engine with command-controlled ignition, a phenomenon commonly referred to as detonation or cylinder head knock occurs: certain points of the charge ignite after reaching appropriate pressure and temperature levels before being reached by the flame front generated by the spark plug 16 (the mega-knock typical of turbocharged engines) or, alternatively, even before the spark plug 16 has generated the electrical arc (pre-ignition); both phenomena are extremely damaging to the mechanical components.

[0044] To increase energy efficiency (i.e., to ensure that all of the injected fuel is always combusted), a very lean mixture is introduced into the combustion chambers of the internal combustion engine 2 (i.e., with much more excess air than the condition that would completely oxidize the fuel). To avoid detonation problems, particularly at high loads, each cylinder 4 is provided with a dedicated passive pre-chamber 43, which defines a smaller area located above the combustion chamber and communicates with it via a limited number of small calibrated holes 44, and in which the electrodes of the spark plug 16 are located. The flame generated in the reduced area of ​​the pre-chamber 43 and introduced into the combustion chamber via the small holes 44 can quickly ignite the fuel-air charge present in the combustion chamber.Thanks to the prechambers 43, even extremely lean mixtures can be completely combusted (i.e., with a lambda value well above one), where otherwise a hot front would tend to lose energy before the actual work is completed. Furthermore, thanks to the prechambers 43, compression ratios can be brought to values ​​that would otherwise be unthinkable in an engine with command-controlled ignition. Finally, thanks to the prechambers 43, very high engine speeds can be achieved (the maximum speed is 15,000 rpm). -1 ), since the combustion of the mixture takes place in a very short time and is therefore compatible with the times available at very high engine speeds.

[0045] According to a preferred embodiment, the crankshaft 6 has main and connecting rod journals dimensioned to withstand the very high pressures in the combustion chambers generated by the rapid combustion (achieved thanks to the pre-chambers 43) and to minimize rotational friction (for example, by using coatings with low friction values).

[0046] In Fig. Figure 17 schematically shows the storage system 27 integrated into the housing 30. In detail, the storage system 27 comprises a plurality of cylindrical batteries 45 (typically between fifty and three hundred batteries 45 are provided) arranged vertically (i.e., with the longitudinal axis of symmetry oriented vertically) to form a grid in which space remains between each battery 45 and the surrounding batteries. A cooling system 46 is provided which cools the batteries 45 and comprises a hydraulic circuit in which a cooling liquid circulates; the hydraulic circuit is configured to direct the cooling liquid inside the housing 30 into an inlet opening and to receive the cooling liquid from the housing 30 into a return opening opposite the inlet opening. A circulation pump 47 and a cooler 48 are arranged along the hydraulic circuit.Arranged inside the housing 30 are a plurality of deflection elements 49 (possibly integrated into the battery holders 45), which are designed and positioned (together with the geometry inside the housing 30) to direct the coolant flow in such a way that the cooling power is evenly distributed among all batteries 45, i.e., so that all batteries 45 are cooled equally. In other words, the deflection elements 49 (together with the geometry inside the housing 30) create paths for the coolant in the housing 30 that guarantee a uniform temperature throughout the entire volume inside the housing 30, thus ensuring an appropriate coolant flow in all areas of the housing 30, even in those areas that are most difficult for the coolant to access.

[0047] The two controllers 26 and 29, which are part of one and the same electronic system in the common housing 30, are, however, connected to another cooling system (not shown) which is separate and independent from the cooling system 46 of the storage system 27 and preferably uses a different cooling liquid than the cooling system 46 of the storage system 27.

[0048] According to the presentation in Fig. 1, the drive unit 1 comprises a fuel tank 50 and a fuel pump 51 which sucks the fuel from the fuel tank 50 and delivers it under pressure to the fuel injection valves 15.

[0049] According to a Fig. 18, three power modules 52 are provided in each controller 26 or 29; that is, each phase of the electrical machine 25 or 28 is controlled by a corresponding power module 52. Each power module 52 is connected to the storage system 27 and can supply a single phase of the corresponding electrical machine 25 or 28 with alternating current; that is, each power module 52 represents a single "leg" of a three-phase inverter. Each power module 52 is equipped with corresponding transistors 53, each representing a gate; of course, the electrical circuit diagram of a Fig. 18 is only one possible and non-limiting example and the power modules 52 could therefore have any other electrical circuit diagram.

[0050] Power modules 52 with innovative materials (in particular a silicon alloy) can be used, which minimize the electrical power losses and thus improve the energy efficiency of the drive unit 1.

[0051] Finally, the drive unit 1 comprises a (in Fig. 1 schematically shown) control unit 54, which monitors the functioning of the drive unit 1.

[0052] Among other things, the control unit 54 determines the degree of opening of the wastegate valve 40 in order to balance the possibility of generating more electricity by the electric machine 28 (the further the wastegate valve 40 is closed, the more electrical energy can be generated by the electric machine 28) and the possibility of increasing the power generated by the internal combustion engine 2 (when the compressor 20 has reached its operating speed, the further the wastegate valve 40 is opened, the lower the exhaust gas back pressure is, and the power generated by the internal combustion engine 2 is consequently greater).In detail, the control unit 54 determines how much electrical energy should be expediently generated by the electrical machine 28 depending on the amount of electrical energy stored in the storage system 27 (it is not useful to generate electrical energy when the storage system 27 is almost fully charged) and depending on the expected use of the electrical machines 28 as motors (it is not useful to generate electrical energy when it is not used), and thus determines the degree of opening of the wastegate valve 40.

[0053] According to a possible embodiment, the control unit 54 is configured to open the wastegate valve 40 at the beginning of a straight, when the speed of the vehicle is still far from the maximum value and consequently increases rapidly, in order to maximize the power of the internal combustion engine 2 and thus deliver a higher torque to the rear drive wheels 24, and to close the wastegate valve 40 in the final section of the straight, when the speed of the vehicle is close to the maximum value and consequently, from an energy point of view, it is more appropriate to slightly reduce the power of the internal combustion engine 2 and forego a few km / h of the maximum speed in order to generate more electrical energy that can be used after braking at the end of the straight to accelerate the vehicle more quickly.In other words, it is generally more appropriate to sacrifice a few km / h of top speed at the end of the straight in exchange for more electrical energy, which can be used to accelerate the vehicle more quickly after braking at the end of the straight, in order to reduce the track time.

[0054] According to a preferred embodiment, the control unit 54 is configured to supplement the main command of the electric machine 28, which is determined as a function of the operating point of the drive unit 1, with a secondary command which provides a cycle in which phases of higher electrical charge (i.e. phases in which the generation of electrical energy is increased by absorbing a higher mechanical power) and phases of lower electrical charge (i.e. phases in which the generation of electrical energy is reduced by absorbing less mechanical power) alternate. The secondary command provides a frequency in the Hertz range, i.e. a frequency between 4 and 9 Hertz. The use of the secondary command (i.e.the relatively slow and cyclical alternation between phases of higher electrical charge and phases of lower electrical charge) enables an increase in the total electrical energy available for use in the acceleration phases for supplying the electrical machine 25.

[0055] Preferably, the secondary command is a square wave that alternately increases and decreases the electrical energy production of the electric machine 28 at a frequency of a few hertz (e.g., 4-6 hertz), resulting in an effect of a few percent compared to the main control. For example, if the main control generates 100, the secondary command cyclically adds 1-4 points with a square wave and reduces by this value, so that the electric machine 28 generates, for example, 98 for a period of a few seconds, and the electric machine 28 generates, for example, 102 for the following period of the same duration.

[0056] It should be noted that when the combustion engine 2 operates at a significantly higher frequency (each cylinder 4 performs combustion at a frequency of 100 Hertz at 12,000 min -1 off) the frequency of the secondary command in the order of a few Hertz prevents any kind of negative interference.

[0057] According to a preferred embodiment, the control unit 54 is configured to detect torsional vibrations in the crankshaft 6 by analyzing the rotational speed of the rotating shaft 6 and, more specifically, the harmonics of the rotating shaft 6. Furthermore, the control unit 54 is configured to compensate (neutralize, cancel) the torsional vibrations in the crankshaft 6 by subjecting the crankshaft 6 to equal and opposite torsional compensation vibrations generated by the electric machine 25 (which is directly connected to the crankshaft 6 via a gear cascade). In other words, the control unit 54 determines the harmonics of the rotational speed of the rotating shaft 6 from moment to moment, and when the intensity of certain frequencies exceeds threshold values, the control unit 54 intervenes and controls the electric machine 25 to generate analog counter-oscillations.In this way, the torsional vibrations of the crankshaft 6 (induced by resonances of the entire drive train consisting of the crankshaft 6, the transmission 23, and the drive shafts) can be eliminated without the use of mechanical dampers, thus significantly reducing torsional inertia, weight, and space requirements. This means that the control unit 54 (if necessary) actively compensates for the high-frequency torsional vibrations of the drive train (consisting of the crankshaft 6, the transmission 23, and the drive shafts) by using the electric motor 25.

[0058] The embodiments described here can be combined with each other.

[0059] The drive unit 1 described above has numerous advantages.

[0060] First and foremost, the drive unit 1 described above enables extremely high maximum power to be achieved while maintaining a particularly moderate weight and space requirement; for example, in the case of an internal combustion engine 2 with a displacement of 1,600 cc, the drive unit 1 can deliver a total peak power of over 1,000 hp.

[0061] In addition, the drive unit 1 described above can operate with very high peak energy efficiency values, which may exceed 50% under certain operating conditions. LIST OF REFERENCE NUMBERS OF THE FIGURES 1 drive unit 2 combustion engine 3 crankcase 4 cylinders 5 pistons 6 Crankshaft 7 cylinder head 8 intake valves 9 Camshaft 10 exhaust valves 11 Camshaft 12 Intake system 13 Exhaust system 14 connecting rods 15 Fuel injection valve 16 Spark plug 17 turbochargers 18 turbines 19 Exhaust pipe 20 Compressor 21 Main intake line 22 intercooler 23 gearboxes 24 rear wheels 25 Electric Machine 26 Control 27 Storage system 28 Electric machine 29 Control 30 housings 31 Air intake 32 final intake lines 33 intake manifold 34 Common pipe 35 inlet trumpets 36 exhaust manifold 37 wheels 38 wheels 39 Wave 40 Wastegate valve 41 Pop-off valve 42 Inlet pipe 43 Antechamber 44 holes 45 Cylindrical batteries 46 Cooling system 47 Circulation pump 48 coolers 49 deflection elements 50 tanks 51 Fuel pump 52 power modules 53 transistors 54 Control unit L length D Diameter

Claims

[1] Drive unit (1) with: a turbocharged internal combustion engine (2) with: a longitudinally oriented crankshaft (6), a crankcase (3), a plurality of cylinders (4) arranged in a "V" shape with an angle of 90° between the two cylinder banks of the cylinders (4), two cylinder heads (7) coupled to the crankcase (3) and forming the roof of the cylinders (4), a plurality of pistons (5), an intake system (12) comprising a main intake line (21) and two intake manifolds (33), each coupled to a cylinder bank of the cylinders (4), an exhaust system (13) with an exhaust pipe (19), and a turbocharger (17) having a turbine (18) arranged along the exhaust pipe (19) and a compressor (20) arranged along the main intake line (21); a system (27) for storing electrical energy; a first reversible electric machine (25) which is mechanically connected to the crankshaft (6) via a gear transmission; a first controller (26) configured to control the first electric machine (25) and coupled to the storage system (27); a second reversible electric machine (28) mechanically coupled to the turbocharger (17); a second controller (29) configured to control the second electric machine (28) and coupled to the storage system (27), and a control unit (54); wherein each cylinder (4) comprises a fuel injection system (15) which cyclically injects the fuel directly into the cylinder (4) and a spark plug (16); wherein the turbocharger (17) comprises a single shaft (39) which is oriented longitudinally like the crankshaft (6) and connects the turbine (18), the compressor (20) and the second electric machine (28) to one another; Drive unit (1) characterized by , that: the second electric machine (28) is arranged next to the compressor (20) on the side opposite the turbine (18); an air inlet pipe (42) is provided which has an inlet opening which receives the air from an air inlet (31) and is arranged radially to the axis of rotation of the compressor (20) and has an outlet opening which is aligned axially to the axis of rotation of the compressor (20) and is coupled to an inlet of the compressor (20); an end piece of the inlet pipe (42) has the shape of a ring which comprises and surrounds a part of the second electrical machine (28) such that the electrical machine (28) is located centrally in the inlet pipe (42) and is pneumatically isolated from the interior of the inlet pipe (42); the compressor (20) and the second electric machine (28) are arranged between the cylinder banks; the turbine (18) is arranged on the outside of the cylinder banks, offset longitudinally relative to the crankcase (3); and the two intake manifolds (33) are arranged above the compressor (20) and above the second electric machine (28). [2] Drive unit (1) according to claim 1, wherein the internal combustion engine (2) comprises a charge air cooler (22) connected along the main intake line (21). [3] Drive unit (1) according to claim 1 or 2, wherein: the internal combustion engine (2) comprises a charge air cooler (22) coupled to the main intake line (21); the main intake line (21) is divided behind the charge air cooler (22) into several end intake lines (32), each of which starts from the main intake line (21), passes through a corresponding intake manifold (33) and opens into a corresponding cylinder (4). [4] Drive unit (1) according to claim 3, wherein each intake manifold (33) is associated with a corresponding cylinder bank of the cylinders (4) and is arranged along all the end intake lines (32) of a cylinder bank of the cylinders (4), so that all the end intake lines (32) of one and the same cylinder bank of the cylinders (4) end at the inlet of the corresponding intake manifold (33) and continue at the outlet of the corresponding intake manifold (33). [5] Drive unit (1) according to claim 4, wherein: all final intake lines (32) of a cylinder bank of cylinders (4) are arranged in a common pipe (34) in front of the corresponding intake manifold (33), while they are divided with different courses behind the corresponding intake manifold (33); and each common pipe (34) has sections inside which keep the corresponding end suction lines (32) pneumatically separated from each other. [6] Drive unit (1) according to claim 5, wherein: arranged inside each intake manifold (33) are inlet trumpets (35) of variable length, which can change their length by means of a telescopic mechanism controlled by an actuator; each inlet trumpet (35) has an outlet arranged in a fixed position from which a corresponding final intake duct (32) extends, and an inlet which can change its position axially, approaching the outlet when the inlet trumpet (35) shortens and moving away from the outlet when the inlet trumpet (35) lengthens. [7] Power unit (1) according to claim 6, wherein the intake trumpets (35) can vary their length between a minimum length which maximizes the internal volume of the intake manifold (33) in which the air of the final intake lines (32) mixes, and a maximum length which reduces the internal volume of the intake manifold (33) in which the air of the final intake lines (32) mixes to zero, since the corresponding final intake line (32) is seamlessly connected from the inlet of the intake manifold (33) to the outlet of the intake manifold (33), bypassing the intake manifold (33), when an intake trumpet (35) has the maximum length. [8] Drive unit (1) according to one of claims 3 to 7, in which the second electric machine (28) and the cylinders (4) of a cylinder bank are arranged between the corresponding end intake lines (32). [9] Drive unit (1) according to one of claims 1 to 8, in which: the exhaust system (13) has two exhaust manifolds (36) which converge in the exhaust pipe (19) and receive the exhaust gases from the corresponding cylinders (4) to which they are individually connected; the exhaust manifold (36) and the exhaust pipe (19) in front of the turbine (18) are thermally insulated on the outside with heat-insulating material. [10] Power unit (1) according to one of claims 1 to 9, in which the corresponding cylinder head (7) has for each cylinder (4) a pre-chamber (43) arranged centrally with respect to the combustion chamber, has its own longitudinal axis parallel to a longitudinal axis of the cylinder (4), contains the corresponding spark plug (16) and has a series of calibrated bores (44) made at the level of a nose of the pre-chamber (43) and connecting the pre-chamber (43) to the combustion chamber of the corresponding cylinder (4). [11] Drive unit (1) according to claim 10, wherein: each pre-chamber (43) has at least six bores (44) and fewer than fifteen bores (44); the ratio between a length (L) and a diameter (D) of each bore (44) is greater than 0.5 and preferably greater than 1; and the internal volume of each pre-chamber (43) is greater than 0.05% and preferably greater than 0.1% of the displacement of the corresponding cylinder (4). [12] Drive unit (1) according to one of claims 1 to 11, in which: the storage system (27) comprises a plurality of cylindrical batteries arranged vertically to form a grid in a housing (30); a cooling system (46) is provided which comprises a hydraulic circuit configured to convey a cooling liquid in the housing (30) into an inlet opening and to receive the cooling liquid from the housing (30) in a return opening opposite the inlet opening; and a plurality of deflection elements (49) are arranged in the housing (30), which are designed and positioned to guide the flow of cooling liquid. [13] Drive unit (1) according to one of claims 1 to 12, wherein the control unit (54) is configured to: to determine how much electrical energy should usefully be generated depending on the amount of electrical energy stored in the storage system (27) and depending on the expected use of the electrical machines (24, 28) as motors; and to determine the degree of opening of the wastegate valve (40) in order to balance the possibility of generating more electrical energy by the second electric machine (28) and the possibility of increasing the power generated by the internal combustion engine (2). [14] Drive unit (1) according to claim 13, wherein the control unit (54) is configured to: to open the wastegate valve (40) at the beginning of a straight when the vehicle speed is still far from its maximum and is increasing rapidly; and to close the wastegate valve (40) at the end of the straight when the vehicle speed is close to the maximum value. [15] Drive unit (1) according to one of claims 1 to 14, wherein the control unit (54) is configured to: to generate a main command of the second electric machine (28) as a function of an operating point of the drive unit (1); to supplement the main command of the second electrical machine (28) by a secondary command, preferably in the form of a square wave, providing a cyclic alternation of phases with higher electrical charge and phases with lower electrical charge and a frequency between 4 and 9 Hertz. [16] Drive unit (1) according to one of claims 1 to 15, wherein the control unit (54) is configured to: to determine the occurrence of torsional vibrations in the crankshaft (6) by analyzing the rotational speed of the rotating shaft (6); and to control the first electric machine (25) to generate equal and opposite compensating torsional vibrations that compensate for the torsional vibrations in the crankshaft (6). [17] Drive unit (1) according to one of claims 1 to 16, wherein the control unit (54) is configured to: to determine the harmonics of the rotational speed of the rotating shaft (6); and to control the first electrical machine (25) to generate analog oscillations in the opposite phase direction when the intensity of certain frequencies exceeds limit values.

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