Power unit

Abstract

The invention relates to a power unit, in particular for a hybrid vehicle, comprising - a reciprocating piston engine (1) which has two pistons (11, 21) guided in cylinders (10, 20) which are arranged in parallel and two crankshafts (12, 22) rotating in opposite directions, which are each connected to the pistons (11, 21) by a separate connecting rod (13, 23), wherein each crankshaft (12, 22) carries a toothed spur gear (14, 24) and said spur gears (14, 24) mesh with one another in order to synchronise a rotation of the crankshafts (12, 22), - a generator (30) which is drivingly connected to the first crankshaft (12) and positioned in extension of a rotational axis of the first crankshaft (12), and - a flywheel mass (40) which is drivingly connected to the second crankshaft (22) and positioned in extension of a rotational axis of the second crankshaft (22). The invention is characterised in that the reciprocating piston engine (1) has two balancing shafts (31, 41), wherein a first balancing shaft (31) is rotationally coupled to the first crankshaft (12) and a second balancing shaft is rotationally coupled to the second crankshaft (22), or in that the reciprocating piston engine (1) has a balancing camshaft (50), in particular a single balancing camshaft, which comprises at least one balancing cam element (51) which is operatively connected to a linearly guided balancing mass (52).

Description

[0001] generator

[0002] The invention relates to a power generator and a vehicle, in particular a hybrid vehicle with such a power generator. A power generator according to the preamble of claim 1 is known from US 2009 / 0107426 A1.

[0003] US 2009 / 0107426 A1 describes a power generator comprising a six-cylinder engine constructed from two inline three-cylinder engines arranged side by side in tandem. Each inline three-cylinder engine comprises a crankshaft, so that the six-cylinder engine has two crankshafts that are synchronized with each other via spur gears and rotate in opposite directions. A generator for generating electricity is arranged at one longitudinal end of the first crankshaft. A flywheel is attached to an opposite longitudinal end of the second crankshaft.

[0004] The disadvantage of the known generator is the large installation space in the longitudinal direction, which is required due to the use of the six-cylinder engine and the opposing positioning of the generator and flywheel.

[0005] Similar generators are known from the prior art, but they use a two-cylinder reciprocating piston engine instead of a six-cylinder engine. In particular, DE 10 2014 115 042 A1, DE 10 2014 115 041 A1, DE 10 2014 115 044 A1, and EP 2 633 166 B1, which originate from the applicant, show such generators. These generators are more compact in the direction parallel to the crankshaft than the generator according to US 2009 / 0107426 A1. To achieve a high level of smoothness in the two-cylinder reciprocating piston engine, the generator in some of these generators serves as a balancing mass and is arranged laterally next to the two-cylinder reciprocating piston engine, i.e., in a plane intersecting both crankshafts. This increases the installation space in the transverse direction of the power unit, which in some cases can be disadvantageous for the so-called packaging in a hybrid vehicle.In addition, transmission elements such as belts are required to connect the generator, which are subject to high loads due to the electromechanical resistance generated in the generator.

[0006] Against this background, the object of the invention is to provide an advanced generator set that is compact in both the transverse and longitudinal directions and offers exceptionally smooth running. Furthermore, the object of the invention is to provide a use of a balancing mechanism in a reciprocating piston engine of a generator set.

[0007] According to the invention, this object is achieved by the power generator according to one of claims 1 and 5 and by the use according to claim 16. The power generators according to claims 1 and 5 constitute alternative solutions for the initially stated object of achieving high compactness in the transverse and longitudinal directions as well as high running smoothness.

[0008] The invention is based on the idea of ​​specifying a power generator, in particular for a hybrid vehicle, wherein the power generator has a reciprocating piston engine with two pistons guided in parallel cylinders and two counter-rotating crankshafts. The crankshafts are each connected to the piston by a separate connecting rod, with each crankshaft carrying a toothed spur gear, and these spur gears mesh with each other to synchronize rotation of the crankshafts. The power generator further comprises a generator that is drive-connected to the first crankshaft and positioned in extension of a rotational axis of the first crankshaft. In addition, a flywheel is provided, which is drive-connected to the second crankshaft and positioned in extension of a rotational axis of the second crankshaft.According to the invention, the reciprocating piston engine has two balance shafts, wherein a first balance shaft is rotationally coupled to the first crankshaft and a second balance shaft is rotationally coupled to the second crankshaft.

[0009] The generator according to the invention is particularly compact, especially in the transverse direction. This is achieved by positioning the generator and the flywheel in line with the rotational axis of the respective crankshaft. In other words, the generator sits directly on a longitudinal end of the first crankshaft. By arranging the generator directly on the crankshaft or in line with the rotational axis of the first crankshaft, additional deflection elements, such as belts, are avoided. This reduces component complexity and thus the manufacturing costs of the generator.

[0010] Likewise, the flywheel is preferably located directly on a longitudinal end of the crankshaft. Two balance shafts are provided to ensure smooth running of the generator, particularly of the reciprocating piston engine. The balance shafts are each rotationally coupled to one of the crankshafts and balance out inertial forces and mass moments of second and higher order. This minimizes vibrations during operation, and in particular, eliminates any vibrations noticeable to vehicle occupants. A hybrid vehicle equipped with the generator thus exhibits driving characteristics otherwise known from purely battery-electric vehicles. The compact generator according to the invention can also be integrated into small hybrid vehicles, and its smooth running significantly increases the driving comfort of such compact vehicles.

[0011] Advantageously, the balance shafts are each connected to the crankshafts by gears. Helical gears can be used, in particular, to create a low-backlash and quiet gear connection. The connection via gears has the additional advantage of positioning the balance shafts close to the center of the reciprocating piston engine, thus improving the compactness of the power unit, particularly in the transverse direction. Specifically, the first balance shaft and the second balance shaft can each carry a gear that meshes with the spur gear of the respective associated crankshaft. In particular, the spur gears of the crankshafts can mesh with each other and each form a toothed connection with one of the gears of the balance shafts.Preferably, the balance shafts are arranged symmetrically with respect to a center plane of the reciprocating piston engine, with the center plane running parallel to the cylinder axes of the reciprocating piston engine and being located between the two cylinders of the reciprocating piston engine. The balance shafts can each carry balancing masses.

[0012] To balance inertia moments and second and higher order inertia forces, it is expedient if the rotational speed of the balance shafts is adjusted accordingly during operation. In a preferred embodiment of the power generator according to the invention, a gear ratio is therefore provided between the balance shafts and the respectively associated crankshafts, which is set up such that the balance shafts rotate during operation at a speed that is twice the rotational speed of the respectively associated crankshaft. In other words, the gear connection between a balance shaft and a crankshaft forms a gear ratio of 2:1. The kinematic chain between the balance shafts and the crankshafts ensures that the two balance shafts rotate at the same speed.Since each of the balance shafts is connected to a crankshaft and the crankshafts are synchronized via intermeshing spur gears, the speed of the balance shafts is also coordinated, achieving a particularly good balance of inertial forces and second- and higher-order inertial moments. This virtually eliminates vibrations during operation of the reciprocating engine.

[0013] The aforementioned object can also be achieved by a power generator, in particular for a hybrid vehicle, comprising a reciprocating piston engine with two pistons guided in parallel cylinders and two counter-rotating crankshafts. The crankshafts are each connected to the pistons by a separate connecting rod, with each crankshaft carrying a toothed spur gear, and these spur gears meshing with one another to synchronize rotation of the crankshafts. The power generator further comprises a generator that is drive-connected to the first crankshaft and positioned in extension of a rotational axis of the first crankshaft. Furthermore, a flywheel is provided that is drive-connected to the second crankshaft and positioned in extension of a rotational axis of the second crankshaft.According to the invention, the reciprocating piston engine has one, in particular a single, compensating camshaft, which comprises at least one compensating cam element which is operatively connected to a linearly guided compensating mass.

[0014] In this variant of the invention, the compactness of the power generator, particularly in the transverse direction, is again achieved by positioning the generator in extension of a rotational axis of the first crankshaft. Likewise, the positioning of the flywheel allows the power generator to be designed to be compact in its width, specifically in the transverse direction. In order to compensate for the second-order inertia moments and inertia forces, this variant features a compensating camshaft that actuates a linearly guided compensating mass. This compensating camshaft can be integrated into the reciprocating piston engine in a very space-saving manner. In this respect, a high level of compactness is achieved, while at the same time an advantageous compensation of inertia forces and second-order inertia moments is achieved. The power generator, in particular its reciprocating piston engine, is therefore characterized by very smooth running.

[0015] A particularly compact design of the generator is achieved when the compensating camshaft is arranged in a plane of symmetry between the two cylinders.

[0016] It is also advantageous if the balancer shaft is gear-connected to at least one of the crankshafts. Generally, the balancer camshaft can also be gear-connected to both crankshafts, particularly their spur gears. Since the crankshafts are synchronized with each other, a single gear connection between the balancer camshaft and one of the crankshafts is sufficient to ensure synchronized operation of the balancer camshaft and crankshafts.

[0017] The balancing mass can be guided linearly parallel to the piston's axis of motion. The inertial moments and inertial forces that occur in reciprocating piston engines are primarily caused by the linear movement of the pistons in the cylinders. To compensate for this, the balancing mass can be guided parallel to this direction of motion.

[0018] The balancing mass can, in particular, be formed by a spring-loaded tappet. The spring-loaded tappet can, for example, be guided in a sleeve that extends essentially above the compensating camshaft, parallel to the cylinders. In particular, the sleeve can be arranged in a plane of symmetry between the two cylinders.

[0019] To further compact the power unit, it can be provided, in particular, that the compensating camshaft is formed by a control camshaft. The control camshaft can, in particular, control cylinder valves. The control camshaft can thus form a combined control and compensating camshaft if the control camshaft also establishes the operative connection to the linearly guided balancing mass.

[0020] The following preferred embodiments and advantages apply both to the power unit with two balance shafts and to the power unit with one balance camshaft.

[0021] In particular, the power generators described here can each have a reciprocating piston engine with a maximum of two cylinders and two pistons. Such a reciprocating piston engine with a maximum of two cylinders and two pistons can, in particular, have exactly two cylinders and two pistons, i.e., be designed as a two-cylinder reciprocating piston engine. Such an engine is particularly compact and runs particularly smoothly thanks to the respective balancing mechanisms, which can comprise two balance shafts or a balance camshaft.

[0022] It is also preferred if the generator is arranged coaxially with the rotational axis of the first crankshaft. Such a connection is particularly simple and eliminates the need for reversing gears, which redirect the torque and often result in losses. Furthermore, this avoids imbalances that could impair the smooth running of the reciprocating engine.

[0023] An increase in efficiency can be achieved if the generator is connected to the first crankshaft via a transmission gear, in particular a planetary gear. The transmission gear can be configured such that the rotational speed of the generator differs from the rotational speed of the crankshafts. This has the advantage that the generator can be designed to be comparatively compact, while at the same time the electrical power generated by the generator is high. Generally, within the scope of the present application, the generator is preferably an electric generator, i.e., one that generates electrical current.

[0024] In a particularly specific embodiment, for example, the planetary gear can have a gear ratio configured such that the generator rotates during operation at a speed greater than the rotational speed of the first crankshaft. In particular, the rotational speed of the generator can be 100% greater than the rotational speed of the first crankshaft. In other words, the generator can rotate during operation at twice the speed of the crankshaft. Greater speed differences are possible.

[0025] The planetary gear, in particular a sun gear and / or a ring gear of the planetary gear, the generator, and the first crankshaft, can share a common axis of rotation. In this respect, the planetary gear can be aligned with the generator and the first crankshaft. This ensures a compact and mechanically simple design, which is particularly easy to implement in series production. At the same time, imbalances are avoided, which benefits the smooth running of the reciprocating engine.

[0026] In a further preferred embodiment of the power generators described here, the generator and the flywheel are arranged on the same side of the reciprocating piston engine. In particular, the crankshafts can each have a first longitudinal end and a second longitudinal end, wherein the first longitudinal ends are arranged in a first common plane and the second longitudinal ends are arranged in a second common plane. The first common plane and the second common plane are each aligned perpendicular to the longitudinal axis of the crankshafts and parallel to one another. Preferably, the generator is arranged on the first longitudinal end of the first crankshaft and the flywheel is arranged on the first longitudinal end of the second crankshaft. The generator and the flywheel can be positioned in a common plane. However, it is preferred if there is an offset between the generator and the flywheel in the longitudinal axial direction of the crankshafts.In particular, the generator can be connected to the first crankshaft via a crankshaft extension.

[0027] The crankshaft extension provides a gap between the crankshaft and the generator, allowing the flywheel to engage within this gap. This allows the flywheel and generator to be arranged offset from each other, making the generator particularly compact, especially in the transverse direction.

[0028] A compact design of the generator in the longitudinal direction, i.e., parallel to the longitudinal axes of the crankshafts, can be achieved by using an axial flux machine. An axial flux machine is characterized by a particularly compact design in the longitudinal direction, thus saving installation space.

[0029] According to a secondary aspect, the invention is based on the idea of ​​specifying the use of a balancing mechanism designed to balance second-order and / or higher-order inertial forces in a reciprocating piston engine of a power generator. The power generator has an electric generator coaxially connected to a crankshaft of the reciprocating piston engine, wherein the balancing mechanism comprises two balancing shafts, each of which is directly gear-coupled to one of two parallel crankshafts. Alternatively, the balancing mechanism has a balancing camshaft that interacts with a linearly movable balancing mass. The power generator can, in particular, be designed as one of the power generators described here.

[0030] The invention will be explained in more detail below using exemplary embodiments with reference to the attached schematic drawings.

[0031] Fig. 1 is a cross-sectional view of a generator set according to the invention with a two-cylinder reciprocating piston engine having a balancing mechanism with two balance shafts,

[0032] Fig. 2 is an exploded view of the generator set according to Fig. 1; and

[0033] Fig. 3 is an exploded view of a generator according to the invention, wherein a compensating camshaft is provided as the compensating mechanism.

[0034] The cross-sectional view according to Fig. 1 shows the reciprocating piston engine 1 of the power generator according to the invention according to a preferred embodiment. Generally speaking, all embodiments include a reciprocating piston engine 1 having a crankcase 2 and a cylinder head 3. The crankcase 1 comprises a first cylinder 10 and a second cylinder 20. The cylinders 10, 20 can, in particular, be formed integrally with the crankcase 2, in particular with an upper crankcase part 2a. The upper crankcase part 2a is preferably fixedly connected to a lower crankcase part 2b. The connection can be made, for example, via a screw connection. Likewise, all embodiments include two pistons, namely a first piston 11 and a second piston 21. The first piston 11 is guided in the first cylinder 10. The second piston 21 is guided in the second cylinder 20.The arrangement of the cylinders 10, 20 and the pistons 11, 21 is designed as a tandem arrangement. This means that the pistons 11, 21 are guided along parallel axes of movement in the cylinders 10, 20. Each of the pistons 11, 21 is connected to a respective crankshaft 12, 22 by means of a connecting rod 13, 23. Specifically, the first piston 11 is coupled to a first crankshaft 12 via a first connecting rod 13. The second piston 21 is coupled to a second crankshaft 22 via a second connecting rod 23. The coupling of the pistons 11, 21 to the crankshafts 12, 22 is preferably carried out in such a way that when the pistons 11, 21 move in the cylinders 10, 20, both pistons 11, 21 each reach top dead center and bottom dead center at the same time.

[0035] The longitudinal axes of the two crankshafts 11, 22 are spaced apart by a distance slightly greater than the distance between the axes of rotation, which is determined by the articulated connection between the respective pistons 11, 21 and the connecting rods 13, 23. In other words, the two cylinders 10, 20 or pistons 11, 21 are arranged indented or offset relative to a plane of symmetry that extends longitudinally centrally through the reciprocating piston engine 1. This has the advantage that the connecting rods 13, 23 are deflected from a vertical at top dead center and bottom dead center of the piston movement, i.e. are arranged at an angle to the axis of rotation of the cylinders 10, 20. This ensures a smooth engine start if the pistons 11, 21 are arranged at one of the dead centers at the time of starting.

[0036] Likewise, for all embodiments of the invention, the reciprocating piston engine 1 comprises the cylinder head 3. The cylinder head 3 closes off the cylinders 10, 20 at the top. In particular, valves 57 are arranged in the cylinder head 3, which open into the combustion chamber of the cylinders 10, 20. Furthermore, spark plugs 58 are provided in the cylinder head 3, which can ignite the fuel mixture in the cylinders 10, 20.

[0037] It is preferred if the valves 57 are controlled by an under-mounted camshaft 55. A camshaft 55 is referred to as under-mounted if it is arranged below the top dead center of the pistons 11, 21. In particular, the camshaft 55 is preferably arranged in the crankcase 2, especially in the upper crankcase part 2a.

[0038] The camshaft 55 is located, in particular, between the two cylinders 10, 20 and preferably in the central plane of symmetry of the reciprocating piston engine 1. The camshaft 55 has a plurality of cams acting on a crankshaft linkage 56. The crankshaft linkage connects the camshaft 55, in particular its cams, to the valves 57. In this way, the camshaft 55 controls the movement of the valves 57.

[0039] In the embodiment according to Fig. 1, the crankcase 52 also comprises two receiving spaces for balance shafts 31, 41. The balance shafts 31, 41 are preferably each equipped with a balancing mass 52. The balancing mass 52 rotates about the axis of rotation of the respective balance shaft 31, 41. For this purpose, the balancing mass 52 is firmly connected to the first balance shaft 31 or the second balance shaft 41, in particular formed in one piece. In other words, the first balance shaft 31 has a balancing mass 52, which can in particular be formed monolithically with the first balance shaft 31. The second balance shaft 41 likewise has a balancing mass 52, which is preferably formed monolithically with the second balance shaft 41. The two balance shafts 31, 41 can be formed identically.

[0040] As can also be seen in Fig. 1, the balance shafts 31, 41 are preferably arranged at the same height as the camshaft 55. Furthermore, the balance shafts 31, 41 are each arranged at the same distance from the central plane of symmetry S.

[0041] Essentially, all embodiments of the power generator according to the invention can have a reciprocating piston engine 1 that is constructed largely as shown in Fig. 1. Deviations from this can consist in the crankshaft housing 2 not comprising any receiving spaces for balance shafts 31, 41. In particular, in some embodiments of the invention, the reciprocating piston engine 1 can be equipped without such balance shafts 31, 41. In particular, in the variant according to Fig. 3, in which a balance camshaft 50 is provided instead of the balance shafts 31, 41, the crankshaft housing 2, in particular the upper crankshaft housing part 2a, can be constructed differently, in particular without receiving spaces for balance shafts 31, 41. The embodiment with balance shafts 31, 41 is shown in detail in an exploded view in Fig. 2.For better clarity, the crankshaft housing and cylinder head 3 have been omitted. Fig. 2 therefore essentially shows an exploded view of the moving parts of the generator set.

[0042] The power generator shown in Fig. 2 includes a reciprocating piston engine 1 having two pistons 11, 21 arranged in tandem. Pistons 11, 21 are each connected to crankshafts 12, 22 via connecting rods 13, 23. A camshaft 55 is provided between the connecting rods and is coupled to valves 57 via a valve linkage 56. Each of the crankshafts 12, 22 carries a spur gear 14, 24.

[0043] The spur gears 14, 24 are each designed as externally toothed gears. The external toothing can be spur or helical. The spur gears 14, 24 are arranged and dimensioned such that their teeth mesh with each other. In this way, the movements of the first crankshaft 12 and the second crankshaft 22 are synchronized.

[0044] Specifically, the first crankshaft 12 carries a first toothed spur gear 14. The second crankshaft 22 carries a second toothed spur gear 24. The spur gears 14, 24 are each connected to longitudinal ends of the crankshafts 11, 22 located in a common plane. The first spur gear 14 meshes with the teeth of the second spur gear 24, and vice versa. Thus, the two spur gears 14, 24 form a spur gear transmission. The gear ratio of the spur gear transmission is 1:1.

[0045] The first crankshaft 12 further carries an electric generator 30. Specifically, the electric generator 30 can be connected to the first spur gear 14 via a planetary gear 33. A crankshaft extension can also be arranged between the first spur gear 14 and the planetary gear 33, so that a distance exists between the first spur gear 14 and the planetary gear 33 and / or the electric generator 30 in the longitudinal axial direction of the crankshaft rotation axis. In general, the generator 30 with the planetary gear 33 can be arranged coaxially to a rotation axis of the first crankshaft 12 and the first spur gear 14. The electric generator 30 is preferably designed as an axial flux machine. Such an axial flux machine is characterized by its small installation depth in the direction of the rotation axis. With high efficiency, the axial flux machine therefore has a short axial length, which is advantageous for the compactness of the power generator.In addition, the axial flux machine is characterized by a high level of efficiency, so that the efficiency of the power generator is increased.

[0046] The second crankshaft 22 carries the second spur gear 24. A flywheel 40 is also connected to the second spur gear 24. The flywheel 40 can be designed as a flywheel disk that is rotationally coupled to the spur gear 24 and / or the crankshaft 22. The flywheel disk 40 is preferably positioned coaxially to the rotational axis of the second crankshaft 22. The flywheel or flywheel disk 40 has an outer diameter that is larger than the outer diameter of the second spur gear 24. In this respect, it is advantageous if a crankshaft extension is arranged between the electric generator or the planetary gear 33 and the first spur gear 14. The crankshaft extension can ensure that there is a longitudinal axial distance between the first spur gear 14 and the planetary gear 33 or the generator 30, in which distance the flywheel 40 can radially engage.In this way, the flywheel 40 can be integrated into the generator set in a space-optimized manner.

[0047] The two balance shafts 31, 41 of the power generator according to Fig. 2 each carry gears 32, 42. In particular, the first balance shaft 31 has a first gear 32 which is arranged at a longitudinal end of the first balance shaft 31. Likewise, the second balance shaft 41 has a second gear 42 which is preferably fixed to a longitudinal end of the second balance shaft 41. The first gear 32 of the first balance shaft 31 meshes with the first spur gear 14. The second gear 42 of the second balance shaft 41 meshes with the second spur gear 24. In this way, each of the balance shafts 31, 41 is gear-connected to one of the crankshafts 12, 22. The gears 32, 42 can have spur gears or helical gears, analogous to the spur gears 14, 24.

[0048] Fig. 3 shows an alternative embodiment in which the balance shafts 31, 41 are omitted. This reduces the installation space required for the power generator, in particular in the transverse direction. The transverse direction is a direction that extends along a plane in which both pistons 11, 21 are arranged. In order to nevertheless balance the second and higher order inertial forces and mass moments that occur during operation of the reciprocating piston engine 1, the camshaft 55 is modified in the embodiment according to Fig. 3. Specifically, the camshaft 55 is extended in order to further form a balance camshaft 50. The extension consists in particular in that the camshaft 55 is supplemented by a balance cam element 51. The camshaft 55 with the balance cam element 51 is therefore referred to as the balance camshaft 50.

[0049] The compensating camshaft 50 fulfills the function of the conventional camshaft 55 and, with its cams, acts on the valve linkage 56 to actuate the valves 57. However, a further function of the compensating camshaft 50 is to set a spring-loaded balancing mass 52 in motion via the compensating cam element 51, with this movement being synchronized in such a way that mass moments of inertia and second- or higher-order mass forces are balanced.

[0050] Specifically, the compensating cam element 51 has four cams that extend essentially in a star shape from the rotational axis of the compensating camshaft 50. The compensating mass 52, which is spring-loaded by a compression spring 53, slides over the cams of the compensating cam element 51. The compression spring 53 thus ensures that the compensating mass 52 is constantly pressed against the compensating cam element 51. For low-friction contact between the compensating mass 52 and the compensating cam element 51, a wheel or roller can be provided that is rotatably connected to the compensating mass 52 and rolls on an outer circumferential surface of the compensating cam element 51.

[0051] The power generators shown in the figures have essentially a similar structure. Figs. 1 and 2 show a first embodiment of a power generator in which two balance shafts 31, 41 are provided to balance the inertial forces and inertial moments of the second or higher order. In the embodiment according to Fig. 3, this balance is achieved by the balance camshaft 50 and the linearly movable balance mass 52. The two embodiments shown differ essentially in the balancing mechanism used in each case. While the balancing mechanism in the embodiment according to Figs. 1 and 2 has two balance shafts 31, 41 connected to the crankshafts 12, 22 by gears, the embodiment according to Fig. 3 features the balance camshaft 50, which acts on a linearly movable balance mass 52.Specifically, two linearly movable balancing masses 52 can be provided, each spring-loaded by a compression spring 53. Fig. 3 shows this variant, in which a spring-loaded balancing mass 52 is also provided at an opposite longitudinal end of the balancing camshaft 50. Accordingly, the balancing camshaft 50 preferably has a balancing cam element 51 at both longitudinal ends.

[0052] List of reference symbols

[0053] 1 reciprocating piston engine

[0054] 2 crankcases

[0055] 2a upper crankcase part

[0056] 2b lower crankcase part

[0057] 3 cylinder head

[0058] 10 first cylinder

[0059] 11 first piston

[0060] 12 first crankshaft

[0061] 13 first connecting rod

[0062] 14 first spur gear

[0063] 20 second cylinder

[0064] 21 second piston

[0065] 22 second crankshaft

[0066] 23 second connecting rod

[0067] 24 second spur gear

[0068] 30 generators

[0069] 31 first balance shaft

[0070] 32 first gear

[0071] 33 planetary gears

[0072] 40 flywheel

[0073] 41 second balance shaft

[0074] 42 second gear

[0075] 50 balance camshaft

[0076] 51 Compensating cam element

[0077] 52 leveling compound

[0078] 53 compression spring

[0079] 55 valve camshaft

[0080] 56 Valve rod 57 Valve

[0081] 58 Spark plug

Claims

Patent claims 1 . Power generator, in particular for a hybrid vehicle, with a reciprocating piston engine (1 ) which drives two cylinders (10, 20) guided pistons (11, 21) and two counter-rotating crankshafts (12, 22), which are each connected to the pistons (11, 21) by a separate connecting rod (13, 23), wherein each crankshaft (12, 22) carries a toothed spur gear (14, 24) and these spur gears (14, 24) mesh with each other in order to synchronize a rotation of the crankshafts (12, 22), a generator (30) which is drivingly connected to the first crankshaft (12) and positioned in extension of a rotational axis of the first crankshaft (12), a flywheel (40) which is drivingly connected to the second crankshaft (22) and positioned in extension of a rotational axis of the second crankshaft (22), characterized in that the reciprocating piston engine (1) has two balance shafts (31, 41), wherein a first balance shaft (31) is rotationally coupled to the first crankshaft (12) and a second balance shaft is rotationally coupled to the second crankshaft (22).

2. Power generator according to claim 1, characterized in that the balance shafts (31, 41) are each connected to the crankshafts (12, 22) by gears.

3. Power generator according to claim 2, characterized in that the first balance shaft (31) and the second balance shaft (41) each carry a gear (32, 42) which meshes with the spur gear (14, 24) of the respectively associated crankshaft (12, 22).

4. Power generator according to one of the preceding claims, characterized in that a transmission is provided between the balance shafts (31, 41) and the respectively associated crankshafts (12, 22), the transmission being arranged such that the balance shafts (31, 41) rotate during operation at a speed which is twice as high as the rotational speed of the respectively associated crankshaft (12, 22).

5. A power generator, in particular for a hybrid vehicle, comprising a reciprocating piston engine (1) having two pistons (11, 21) guided in parallel cylinders (10, 20) and two counter-rotating crankshafts (12, 22) which are each connected to the pistons (11, 21) by a separate connecting rod (13, 23), each crankshaft (12, 22) carrying a toothed spur gear (14, 24) and these spur gears (14, 24) meshing with each other to synchronize rotation of the crankshafts (12, 22), a generator (30) drivingly connected to the first crankshaft (12) and positioned in extension of a rotational axis of the first crankshaft (12), a flywheel (40) drivingly connected to the second crankshaft (22) and positioned in extension of a rotational axis of the second crankshaft (22), characterized characterized in that the reciprocating piston engine (1) has one, in particular a single, compensating camshaft (50),which comprises at least one compensating cam element (51) which is operatively connected to a linearly guided compensating mass (52).

6. Generator according to claim 5, characterized in that the compensating camshaft (50) is arranged in a plane of symmetry between the two cylinders (10, 20).

7. Generator according to claim 5 or 6, characterized in that the compensating camshaft (50) is gear-connected to at least one of the crankshafts (12, 22).

8. Power generator according to one of claims 5 to 7, characterized in that the balancing mass (53) is guided linearly parallel to a movement axis of the pistons (11, 21).

9. Power generator according to one of the preceding claims, characterized in that the reciprocating piston engine (1) has a maximum of two cylinders (10, 20) and two pistons (11, 21).

10. Power generator according to one of the preceding claims, characterized in that the generator (30) is arranged coaxially to the axis of rotation of the first crankshaft (12, 22). 11 . Power generator according to one of the preceding claims, characterized in that the generator (30) is connected to the first crankshaft via a transmission gear, in particular a planetary gear (33).

12. Power generator according to claim 11, characterized in that the planetary gear (33) has a transmission ratio which is configured such that the generator (30) rotates during operation at a speed which is greater, in particular 100% greater, than the rotational speed of the first crankshaft (12).

13. Power generator according to claim 11 or 12, characterized in that the planetary gear, in particular a sun gear and / or a ring gear of the Planetary gear, the generator and the first crankshaft have a common axis of rotation.

14. Power generator according to one of the preceding claims, characterized in that the generator (30) and the flywheel (40) are arranged on the same side of the reciprocating piston engine (1).

15. Power unit according to one of the preceding claims, characterized in that the generator (30) is formed by an axial flux machine.

16. Use of a second and / or higher mass force generator for balancing order arranged balancing mechanism' in a reciprocating piston engine (1) of a power generator, wherein the power generator has an electric generator (30) coaxially connected to a crankshaft (12, 22) of the reciprocating piston engine (1), and wherein the balancing mechanism has two balancing shafts (31, 41), each of which is directly gear-coupled to one of two parallel crankshafts (12, 22), or a balancing camshaft (50) which interacts with a linearly movable balancing mass (52).

17. Use according to claim 16, wherein the power generator is designed according to one of claims 1 to 15.

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