Reciprocating piston engine

Abstract

A reciprocating piston engine is disclosed having a first inner magnetic field unit comprising a first inner magnetic field unit arranged on a first crank arm of a crankshaft including a magnetizable material, and a stationary first outer magnetic field unit. The first inner magnetic field unit and the first outer magnetic field unit together form a first electromechanical converter. The first crank arm has a first securing surface on a face which points radially outwards with respect to a crankshaft axis and which is opposite a first connecting rod bearing. A first counterweight is fixed to the first securing surface in a formfitting manner in the radial direction, said first counterweight including a non-magnetizable material. The first magnetic field unit is arranged on a counterweight face pointing radially outwards with respect to the crankshaft axis.

Claims

1. A reciprocating-piston engine, having a cylinder block, a crank chamber which is formed at least partially in the cylinder block, a crankshaft comprises a magnetizable material and is arranged within the crank chamber so as to be rotatable about a geometric crankshaft axis, at least one first connecting rod which is mounted rotatably in a first connecting-rod bearing of the crankshaft and which, during rotation of the crankshaft, performs a connecting-rod movement in a geometric connecting-rod movement space, a first inner magnetic field unit, said first inner magnetic field unit being arranged on a first crank web, which is axially adjacent to the first connecting-rod bearing in relation to the crankshaft axis, of the crankshaft in such a way that the first inner magnetic field unit points radially outward in relation to the crankshaft axis and, during rotation of the crankshaft, circulates around the crankshaft axis on a geometric first circular path which is axially adjacent to the connecting-rod movement space, and a first outer magnetic field unit which is arranged in static fashion in the crank chamber so as to be radially spaced apart from the first circular path, wherein the first inner magnetic field unit and the first outer magnetic field unit are arranged and designed such that, together, they form a first electromechanical converter, an electric motor or an electrical generator, wherein, the first crank web has a first fastening surface on a side which points radially outward in relation to the crankshaft axis and which is situated opposite the first connecting-rod bearing, a first balancing weight is fixed in positively locking fashion in a radial direction to the first fastening surface, the first balancing weight comprises a non-magnetizable material, and the first inner magnetic field unit is arranged on a side, which points radially outward in relation to the crankshaft axis, of the first balancing weight.

2. The reciprocating-piston engine as claimed in claim 1, wherein, the first inner magnetic field unit is pushed into a first linear guide, which extends in an axial direction and which fixes the first inner magnetic field unit in positively locking fashion in a radial direction and circumferential direction in relation to the crankshaft axis, on the first balancing weight and is fixed axially there.

3. The reciprocating-piston engine as claimed in claim 1, wherein, the first balancing weight comprises at least one, or combinations, of the following non-magnetizable materials: cast-iron, austenitic cast iron, gray cast iron; high-grade steel; carbon fiber, sintered carbon fiber; ceramic material; aluminum.

4. The reciprocating-piston engine as claimed in any one of claims 1, wherein, the first inner magnetic field unit has the shape of a circular-arc-shaped inner ring section which surrounds the first crank web and which has a geometric first axis which lies on the crankshaft axis, and, the circular-arc-shaped inner ring section extends with a first center angle () of greater than 135.

5. The reciprocating-piston engine as claimed in claim 4, wherein, the circular-arc-shaped inner ring section extends with a first center angle () of 360, and the first inner magnetic field unit has the shape of a closed circular inner ring surrounding the first crank web.

6. The reciprocating-piston engine as claimed in any one of claims 1, wherein, the first outer magnetic field unit has the shape of a circular-arc-shaped outer ring section which surrounds the first circular path of the first inner magnetic field unit with a radial spacing and which has a geometric second axis which lies on the crankshaft axis, and, the circular-arc-shaped outer ring section extends with a second center angle () of greater than 135.

7. The reciprocating-piston engine as claimed in claim 6, wherein, the circular-arc-shaped outer ring section extends with a second center angle () of 360, and the first outer magnetic field unit has the shape of a closed circular outer ring which surrounds the first circular path of the first inner magnetic field unit with a radial spacing.

8. The reciprocating-piston engine as claimed in any one of claims 1, wherein, the first inner magnetic field unit is permanently magnetic and is in the form of a first inner permanent magnet unit.

9. The reciprocating-piston engine as claimed in claim 8, wherein, the first inner permanent magnet unit has first permanent magnets arranged in a line with one another in a circle-circumferential direction in relation to the crankshaft axis, in such a way that the magnetic polarity of the first permanent magnets alternates in the circle-circumferential direction such that a magnetic alternating field is generated during rotation of the crankshaft, wherein, the first permanent magnets are arranged adjacent to one another, along the circular-arc-shaped inner ring section, and have north poles (N) pointing in a common circumferential direction, or the first permanent magnets are arranged adjacent to one another, along the circular-arc-shaped inner ring section, and have poles (N, S) of alternating polarity orientation pointing in a radial direction.

10. The reciprocating-piston engine as claimed in any one of claims 1, wherein, the first inner magnetic field unit is electromagnetic and is in the form of a first inner coil unit.

11. The reciprocating-piston engine as claimed in claim 10, wherein, the first inner coil unit has first coils which are arranged in a line with one another in a circle-circumferential direction in relation to the crankshaft axis, the first coil axes of which first coils run radially in relation to the crankshaft axis, wherein, the first coils are arranged and/or interconnected such that the magnetic polarity of the first coils alternates in the circle-circumferential direction, such that a magnetic alternating field is generated during rotation of the crankshaft, or at least one first coil which extends in a circle-circumferential direction and the first coil axis of which runs in the circle-circumferential direction, or at least one first coil, the first coil axis of which runs parallel to the crankshaft axis.

12. The reciprocating-piston engine as claimed in claim 11, wherein, the first inner coil unit has at least one additional coil which is electrically connected to the at least one first coil, a permanently magnetic or electromagnetic lateral magnetic field unit is arranged in static fashion in the crank chamber (2) axially adjacent to the first circular path of the first inner coil unit, and the at least one additional coil and the lateral magnetic field unit are arranged relative to one another, in axially opposed positions with respect to one another in relation to the crankshaft axis, and designed, such that, during rotation of the crankshaft about the crankshaft axis, said at least one additional coil and lateral magnetic field unit together form an electrical generator for the supply of electrical voltage to the at least one first coil.

13. The reciprocating-piston engine as claimed in claim 12, wherein, the at least one additional coil has an additional-coil axis running parallel to the crankshaft axis, or the at least one additional coil is formed by multiple additional coils arranged in a line with one another in a circle-circumferential direction, with additional coil axes running parallel to the crankshaft axis, wherein, the lateral magnetic field unit is electromagnetic and is formed by multiple lateral coils arranged in a line with one another in a circle-circumferential direction, with lateral-coil axes running parallel to the crankshaft axis.

14. The reciprocating-piston engine as claimed in any one of claims 1, wherein, the first outer magnetic field unit is electromagnetic and is in the form of a first outer coil unit.

15. The reciprocating-piston engine as claimed in claim 14, wherein, the first outer coil unit has second coils which are arranged in a line with one another in a circle-circumferential direction and the second coil axes of which run radially in relation to the crankshaft axis, or at least one second coil which extends in a circle-circumferential direction and the second coil axis of which runs in the circle-circumferential direction, or at least one second coil, the second coil axis of which runs parallel to the crankshaft axis.

16. The reciprocating-piston engine as claimed in claim 10, wherein, the first outer magnetic field unit is permanently magnetic and is in the form of a first outer permanent magnet unit.

17. The reciprocating-piston engine as claimed in claim 16, wherein, the first outer permanent magnet unit has second permanent magnets arranged in a line with one another in a circle-circumferential direction in relation to the crankshaft axis, in such a way that the magnetic polarity of the second permanent magnets alternates in the circle-circumferential direction such that a magnetic alternating field is generated during rotation of the crankshaft, wherein, the second permanent magnets are arranged adjacent to one another along the circular-arc-shaped inner ring section, and have north poles (N) pointing in a common circumferential direction, or the second permanent magnets are arranged adjacent to one another along the circular-arc-shaped inner ring section, and have poles (N, S) of alternating polarity orientation pointing in a radial direction.

18. The reciprocating-piston engine as claimed in any one of claims 1, further comprising: a second inner magnetic field unit, said second inner magnetic field unit being arranged on a second crank web, which is axially adjacent to the first connecting-rod bearing and which is situated axially opposite the first crank web, of the crankshaft in such a way that the second inner magnetic field unit points radially outward in relation to the crankshaft axis and, during rotation of the crankshaft, circulates around the crankshaft axis on a geometric second circular path which is axially adjacent to the connecting-rod movement space, and a second outer magnetic field unit which is arranged in static fashion in the crank chamber so as to be radially spaced apart from the second circular path, in such a way that the second outer magnetic field unit and the second inner magnetic field unit together form a second electromechanical converter, wherein the connecting-rod movement space of the at least one first connecting rod extends in an axial intermediate space between the first circular path and the second circular path, the second crank web has a second fastening surface on a side which points radially outward in relation to the crankshaft axis and which is situated opposite the first connecting-rod bearing, a second balancing weight is fixed in positively locking fashion in a radial direction to the second fastening surface, the second balancing weight comprises a non-magnetizable material, and the second inner magnetic field unit is arranged on a radially outwardly pointing side of the second balancing weight, wherein, the second inner magnetic field unit corresponds to the first inner magnetic field unit, and/or the second outer magnetic field unit corresponds to the first outer magnetic field unit, and/or the second balancing weight corresponds to the first balancing weight.

19. A system comprising: the reciprocating-piston engine as claimed in claim 1, a chargeable and dischargeable electrical energy store, an electrical control unit, and a crankshaft sensor for detecting a position of the crankshaft, wherein the control unit is electrically interconnected with the electrical energy store, with the first electromechanical converter and with the second electromechanical converter, and designed, such that the reciprocating-piston engine can be switched between an electric-motor operating mode, in which the crankshaft can be driven with electric motor action by virtue of the electrical energy store being discharged, and a generator operating mode, in which the electrical energy store can be charged by virtue of the crankshaft being mechanically driven, by virtue of the crankshaft being driven with combustion engine action by way of the reciprocating-piston engine, and the reciprocating-piston engine has an electrically actuable variable outlet valve drive for at least one first outlet valve which is assigned to a first combustion chamber of a first piston which is coupled to the at least one first connecting rod, said electrically actuable variable outlet valve drive being designed such that the at least one first outlet valve can be opened regardless of the position of the crankshaft, wherein, the control unit is interconnected with the crankshaft sensor and with the variable outlet valve drive, and designed, such that, in the electric-motor operating mode, the at least one first outlet valve is opened in a position range of the crankshaft in which the first piston is situated in a compression stroke.

20. The system, as claimed in claim 19, comprising: the reciprocating-piston engine, a chargeable or dischargeable electrical energy store, an electric power control element and a crankshaft sensor for detecting a position of the crankshaft, wherein the reciprocating-piston engine has a first piston, which is assigned to the first electromechanical converter and to the second electromechanical converter and which is coupled to the at least one first connecting rod, and a second piston, which is assigned to a third electromechanical converter, the latter corresponding to the first electromechanical converter, and which is coupled to at least one second connecting rod which is mounted rotatably in a second connecting-rod bearing of the crankshaft, and the power control element is electrically interconnected with the electrical energy store, with the first electromechanical converter and with the third electromechanical converter, and designed, such that, in an electric-motor operating mode, the crankshaft can be driven with electric motor action with adjustable power by virtue of the electrical energy store being discharged, or, in a generator operating mode, the electrical energy store can be charged with adjustable power by virtue of the crankshaft being mechanically driven, by virtue of the crankshaft being driven with combustion engine action by way of the reciprocating-piston engine, wherein, the power control element is electrically interconnected with the electrical energy store, with the first electromechanical converter, with the third electromechanical converter and with the crankshaft sensor, and designed, such that the power is distributed to the first electromechanical converter with a first power fraction and to the third electromechanical converter with a second power fraction, the distribution of the power to the first electromechanical converter and to the third electromechanical converter is performed in a manner dependent on the position of the crankshaft, and, the distribution of the power is performed in a manner dependent on the position of the crankshaft in such a way that inertia forces and torques of relatively high order, of second order, arising as a result of the movement of the crankshaft, of the at least one first connecting rod, of the at least one second connecting rod, of the first piston and/or of the second piston are reduced or compensated.

Description

(1) In detail, in the drawings:

(2) FIG. 1a shows, in an oblique view, a first exemplary embodiment of the reciprocating-piston engine according to the invention with closed ring-shaped inner permanent magnet units and circular-arc-shaped outer coil units;

(3) FIG. 1b shows, in a cross-sectional view from a front elevation, the first exemplary embodiment incorporated into a system;

(4) FIG. 1c shows, in a cross-sectional view from a side elevation, the first exemplary embodiment with the piston at bottom dead center;

(5) FIG. 1d shows, in a cross-sectional view from a side elevation, the first exemplary embodiment with the piston at top dead center;

(6) FIG. 1e shows, in an oblique view, the crankshaft of the first exemplary embodiment without balancing weights;

(7) FIG. 1f shows, in an oblique view, a balancing weight of the first exemplary embodiment;

(8) FIG. 1g shows, in an oblique view, the crankshaft of the first exemplary embodiment with balancing weights;

(9) FIG. 1h shows, in an oblique view, the crankshaft of the first exemplary embodiment with balancing weights and the ring-shaped inner permanent magnet units;

(10) FIG. 1i shows, in an oblique view, the ring-shaped inner permanent magnet unit of the first exemplary embodiment with first permanent magnets arranged adjacent to one another with north poles pointing in a common circumferential direction;

(11) FIG. 1j shows, in an oblique view, the circular-arc-shaped outer coil unit of the first exemplary embodiment, having a second center angle of 180, with a second coil with a second coil axis running parallel to the crankshaft axis;

(12) FIG. 2a shows, in an oblique view, a first alternative embodiment of the crankshaft with circular-arc-shaped inner permanent magnet units with a first center angle of 180;

(13) FIG. 2b shows, in an oblique view, the circular-arc-shaped inner permanent magnet unit of the first alternative embodiment of the crankshaft with a first center angle of 180;

(14) FIG. 3a shows, in an oblique view, a second exemplary embodiment of the reciprocating-piston engine according to the invention with closed ring-shaped inner permanent magnet units and circular-arc-shaped outer coil units;

(15) FIG. 3b shows, in an oblique view, the crankshaft of the second exemplary embodiment with balancing weights and with the ring-shaped inner permanent magnet units;

(16) FIG. 3c shows, in an oblique view, the ring-shaped inner permanent magnet unit of the second exemplary embodiment with adjacently arranged first permanent magnets with poles of alternating polarity orientation pointing in a radial direction;

(17) FIG. 3d shows, in an oblique view, the circular-arc-shaped outer coil unit of the second exemplary embodiment, having a second center angle of 180, with a second coil with a second coil axis running in a circle-circumferential direction;

(18) FIG. 4a shows, in an oblique view, a third exemplary embodiment of the reciprocating-piston engine according to the invention with closed ring-shaped inner permanent magnet units and closed ring-shaped outer coil units;

(19) FIG. 4b shows, in an oblique view, the crankshaft of the third exemplary embodiment with balancing weights and with the ring-shaped inner permanent magnet units;

(20) FIG. 4c shows, in an oblique view, the ring-shaped inner permanent magnet unit of the third exemplary embodiment with adjacently arranged first permanent magnets with poles of alternating polarity orientation pointing in a radial direction;

(21) FIG. 4d shows, in a cross-sectional view from a side elevation, the ring-shaped outer coil unit of the third exemplary embodiment, having second coils which are arranged in a line with one another in a circle-circumferential direction and which have second coil axes running radially in relation to the crankshaft axis;

(22) FIG. 5a shows, in an oblique view, a fourth exemplary embodiment of the reciprocating-piston engine according to the invention with closed ring-shaped inner permanent magnet units and closed ring-shaped outer coil units;

(23) FIG. 5b shows, in an oblique view, the ring-shaped outer coil unit of the fourth exemplary embodiment with a second coil with a second coil axis running parallel to the crankshaft axis;

(24) FIG. 6 shows, in a cross-sectional view from a side elevation, a second alternative embodiment having a ring-shaped inner coil unit with first coils which are arranged in a line with one another in a circle-circumferential direction and which have first coil axes running radially in relation to the crankshaft axis, and having a ring-shaped outer permanent magnet unit with adjacently arranged second permanent magnets which have poles of alternating polarity orientation pointing in a radial direction;

(25) FIG. 7a shows, in a cross-sectional view from a side elevation, a third alternative embodiment having a ring-shaped inner coil unit with first coils which are arranged in a line with one another in a circle-circumferential direction and which have first coil axes running radially in relation to the crankshaft axis, and having a ring-shaped outer coil unit with second coils which are arranged in a line with one another in a circle-circumferential direction and which have second coil axes running radially in relation to the crankshaft axis; and

(26) FIG. 7b shows, in a cross-sectional illustration A-A from FIG. 7a, an additional coil, which is connected to a first coil, of the inner coil unit, and a lateral coil.

(27) Since the figures show, in part, the same exemplary embodiment from different views and in different degrees of detail, and the exemplary embodiments, in part, differ only by certain features, the following description of the figures will, in part, not provide a repeated explanation of reference designations and features that have already been mentioned previously, and, in part, only the differences between the individual exemplary embodiments will be discussed.

(28) FIGS. 1a to 1j illustrate a first exemplary embodiment of the reciprocating-piston engine according to the invention from different views and in different degrees of detail. Said figures will be discussed jointly below.

(29) The reciprocating-piston engine of the first exemplary embodiment is a four-cylinder in-line engine which operates on the basis of the Otto-cycle engine principle, as shown in figures la and lb. The reciprocating-piston engine is assembled substantially from a cylinder block 1, a crank chamber 2 which is formed partially in the cylinder block 1 and which is delimited at the bottom by an oil pan 52, a crankshaft 3, and four pistons 27 and 31, which are connected to the crankshaft 3 by way of four connecting rods 5 and 32. Below, for simplicity, a partial description will be given of only the first piston 27 and the second piston 31 and the peripherals thereof.

(30) The crankshaft 3 is arranged within the crank chamber 2, so as to be rotatable about a geometric crankshaft axis 4, in a total of five main bearings 44a and 44b, and is held there by way of five bearing covers 49, which are fixed to the cylinder block 1 by way of bearing cover screws 50, as illustrated in FIG. 1a.

(31) The crankshaft 3 is formed in one piece from a magnetizable material.

(32) The first connecting rod 5 is mounted rotatably in a first connecting-rod bearing 6 of the crankshaft 3 and, during rotation of the crankshaft 3, performs a connecting-rod movement in a geometric connecting-rod movement space 7. The first piston 27 is mounted in a connecting-rod eye of the first connecting rod 5, as shown in FIGS. 1a and 1b.

(33) The second connecting rod 32 is mounted rotatably in a second connecting-rod bearing 33 of the crankshaft 3 and, during rotation of the crankshaft 3, likewise performs a connecting-rod movement in a geometric connecting-rod space.

(34) The same applies to the further connecting rods, connecting-rod bearings and pistons. Below, the arrangement thereof will be described, in part, merely on the basis of the first connecting rod 5, the first connecting-rod bearing 6 and the first piston 27.

(35) The first connecting-rod bearing 6 of the crankshaft 3 is connected via a first crank web 9a to the adjacent first main bearing 44a and via a second crank web 9b, which is situated opposite the first crank web 9a, to the second main bearing 44b, wherein the crank webs 9a and 9b give rise to the radial offset of the first connecting-rod bearing 6 in relation to the crankshaft axis 4, as shown in FIG. 1e.

(36) The first crank web 9a has a first fastening surface 13a on a side which points radially outward in relation to the crankshaft axis 4 and which is situated opposite the first connecting-rod bearing 6. Also, the second crank web 9b has a second fastening surface 13b on a side which points radially outward in relation to the crankshaft axis 4 and which is situated opposite the first connecting-rod bearing 6, as illustrated in FIG. 1e. The fastening surfaces 13a and 13b, which are situated opposite the first connecting-rod bearing 6, are planar and lie in a common plane. Correspondingly, in each case two fastening surfaces are also situated opposite the other connecting-rod bearings of the crankshaft 3, such as for example the third fastening surface 13c situated opposite the second connecting-rod bearing 33 on the third crank web 9c, and the fourth fastening surface 13c situated opposite the second connecting-rod bearing 33 on the fourth crank web 9d, corresponding to FIG. 1e.

(37) A first balancing weight 14a is fixed in positively locking fashion in a radial direction to the first fastening surface 13a, a second balancing weight 14b is fixed in positively locking fashion in a radial direction to the second fastening surface 13b, a third balancing weight 14c is fixed in positively locking fashion in a radial direction to the third fastening surface 13c, and a fourth balancing weight 14d is fixed in positively locking fashion in a radial direction to the fourth fastening surface 13d. The same applies to the other fastening surfaces. The positively locking fixing of the balancing weights 14a, 14b, 14c and 14d to the fastening surfaces 13a, 13b, 13c and 13d is realized in each case by way of two balancing-weight screws 45, wherein the respective balancing weight 14a, 14b, 14c and 14d is centered on the respective fastening surface 13a, 13b, 13c and 13d by way of a centering bolt 46, as shown in FIGS. 1f and 1g. The balancing weights 14a, 14b, 14c and 14d are, like the other balancing weights, composed of a non-magnetizable material, for example cast iron, high-grade steel, carbon fiber, a ceramic material or aluminum. All of the balancing weights correspond to one another.

(38) A first inner magnetic field unit 8a is arranged on a side, which points radially outward in relation to the crankshaft axis 4, of the first balancing weight 14a. Thus, the first inner magnetic field unit 8a is arranged, indirectly via the first balancing weight 14a, on the first crank web 9a, which is axially adjacent to the first connecting-rod bearing 6, of the crankshaft 3, as shown in FIGS. 1b and 1h.

(39) Corresponding to this arrangement, a second inner magnetic field unit 8b is arranged on the second crank web 9b, which is axially adjacent to the first connecting-rod bearing 6 and situated axially opposite the first crank web 9a, of the crankshaft 3 by virtue of the second inner magnetic field unit 8b being fixed to that side of the second balancing weight 14b which points radially outward.

(40) Accordingly, inner magnetic field units, for example a third magnetic field unit 8c, are also arranged on the other balancing weights, as is likewise shown in FIGS. 1b and 1h.

(41) The inner magnetic field units 8a, 8b and 8c are in each case pushed into a first linear guide 17a or second linear guide 17b or third linear guide 17c, respectively, which extends in an axial direction, that is to say parallel to the crankshaft axis 4, on the respective balancing weight 14a or 14b or 14c, and are fixed axially there such that said inner magnetic field units cannot be displaced, as is shown in FIGS. lb and 1h. The linear guides 17a, 17b and 17c fix the respective inner magnetic field unit 8a, 8b or 8c in a radial direction in relation to the crankshaft axis 4, that is to say outward in a centrifugal direction, and in a circumferential direction, that is to say rotationally, in positively locking fashion by way of an undercut. A detailed view of the first linear guide 17a, which is formed in the first inner magnetic field unit 8a and the first balancing weight 14a, is shown in FIGS. 1f, 1g and 1i. The second linear guide 17b of the second balancing weight 14b is shown in FIG. 1g.

(42) The first inner magnetic field units 8a, 8b and 8c have the shape of a closed circular inner ring which surrounds the respective crank web 9a, 9b or 9c and which has a geometric first axis 15 which lies on the crankshaft axis 4. In other words, said first inner magnetic field units have the shape of a circular-arc-shaped inner ring section which surrounds the respective crank web 9a, 9b or 9c and which has a common geometric first axis 15 which lies on the crankshaft axis 4, wherein the circular-arc-shaped inner ring section extends with a first center angle of 360, such that the respective circular arc is closed to form a ring, as shown in FIG. 1i.

(43) For better stabilization of all of the ring-shaped inner magnetic field units 8a, 8b and 8c, these are each connected to the respective connecting-rod bearing 6 by way of stabilizing bolts 47, FIG. 1g.

(44) All of the inner magnetic field units, eight inner magnetic field units in the present exemplary embodiment, correspond to one another, FIG. 1h.

(45) The inner magnetic field units 8a, 8b and 8c are permanently magnetic and are each in the form of an inner permanent magnet unit 8a, 8b and 8c respectively. Accordingly, the first inner permanent magnet unit 8a has, in relation to the crankshaft axis 4, a multiplicity of first permanent magnets 16 arranged in a line with one another in a circle-circumferential direction, wherein said first permanent magnets 16 are arranged adjacent to one another along the circular inner ring and have north poles N pointing in a common circumferential direction, such that the magnetic polarity of the first permanent magnets 16 alternates in the circle-circumferential direction, such that a magnetic alternating field is generated during rotation of the crankshaft 3, as shown in FIG. 1i. In other words, the permanent magnet units 8a, 8b and 8c are formed by magnet rings which, along the ring circumference, have a multiplicity of alternating magnetic north poles N and south poles S, such that north poles N and south poles S alternate with one another in the circle-circumferential direction.

(46) Thus, the first inner magnetic field unit 8a, the second inner magnetic field unit 8b and the third inner magnetic field unit 8c point radially outward in relation to the crankshaft axis 4. Furthermore, during rotation of the crankshaft 3, said inner magnetic field units circulate around the crankshaft axis 4, in each case on a geometric circular path which is axially adjacent to the connecting-rod movement space 7; specifically, the first inner magnetic field unit 8a circulates on the first circular path 10a, and the second inner magnetic field unit 8b circulates on the second circular path 10b, as shown in FIGS. 1b and 1h.

(47) The connecting-rod movement space 7 of the first connecting rod 5 is situated in the axial intermediate space between the first circular path 10a and the second circular path 10b, as indicated in FIG. 1b. This applies correspondingly to the other connecting rods.

(48) A first outer magnetic field unit 11a is arranged in static fashion in the crank chamber 2 so as to be radially spaced apart from the first circular path 10a of the ring-shaped first inner permanent magnet unit 8a. A second outer magnetic field unit 11b is provided, likewise in static fashion, in the crank chamber 2 so as to be parallel to and spaced apart from the first outer magnetic field unit 11a, which second outer magnetic field unit surrounds the second circular path 10b of the ring-shaped second inner permanent magnet unit 8b with a radial spacing, as indicated in figures 1a, 1b, 1c and 1d. Accordingly, each inner permanent magnet unit is assigned an outer magnetic field unit.

(49) All of the outer magnetic field units 11a, 11b, 11c and 11d have the shape of a circular-arc-shaped outer ring section which surrounds the respective circular path of the respective inner magnetic field unit 8a, 8b, 8c and 8d and which has a geometric second axis 18 which lies on the crankshaft axis 4, FIGS. 1a, 1c, 1d and 1j. Said respective circular-arc-shaped outer ring section has a second center angle of 180, as illustrated in FIG. 1j.

(50) All of the outer magnetic field units 11a, 11b, 11c and lid are electromagnetic and are in the form of outer coil units 11a, 11b, 11c and lid respectively. These have in each case one second coil 19c, the second coil axis 20c of which runs parallel to the crankshaft axis 4, FIG. 1j.

(51) The first inner permanent magnet unit 8a and the first outer coil unit 11a are thus arranged and designed such that, together, they form a first electromechanical converter 12a. During rotation of the crankshaft 3 and thus also of the first inner permanent magnet unit 8a, a magnetic alternating field is generated in the first outer coil unit 11a, whereby an alternating voltage is induced in the second coil 19c. Said voltage may for example be utilized for charging an electrical energy store. The first electromechanical converter 12a is, in this case, an electrical generator.

(52) Conversely, by application of an alternating voltage to the second coil 19c of the first outer coil unit 11a, a magnetic force can be exerted on the first inner permanent magnet unit 8a, such that the first inner permanent magnet unit 8a and thus also the crankshaft 3 can be set in rotation. In this case, the first electromechanical converter 12a forms an electric motor.

(53) A corresponding situation applies to the second inner permanent magnet unit 8a and the second outer coil unit 11a, to the third inner permanent magnet unit 8a and the third outer coil unit 11a, and to the fourth inner permanent magnet unit 8a and the fourth outer coil unit 11a, which form a second electromechanical converter 12b, a third electromechanical converter 12c and a fourth electromechanical converter 12d respectively.

(54) The reciprocating-piston engine has an electrically actuable variable outlet valve drive 24 for a first outlet valve 25 which is assigned to a first combustion chamber 26 of the first piston 27, and for each further outlet valve of the other pistons. The variable outlet valve drive 24 is designed such that the first outlet valve 25 and each further outlet valve can be opened independently of the position of the crankshaft 3.

(55) The reciprocating-piston engine is incorporated into a system which is schematically indicated in FIG. 1b and which comprises a chargeable and dischargeable electrical energy store 21, an electrical control unit 22, an electrical power control element 30, and a crankshaft sensor 23 for detecting an angular position of the crankshaft 3.

(56) The control unit 22 is electrically interconnected with the electrical energy store 21, with the first electromechanical converter 12a, with the second electromechanical converter 12b and with all further electromechanical converters. Furthermore, the control unit 22 is designed such that the reciprocating-piston engine can be switched between an electric-motor operating mode and a generator operating mode. In the electric-motor operating mode, the crankshaft 3 is driven with electric motor action by virtue of the electrical energy store 21 being discharged. In the generator operating mode, the electrical energy store is charged by virtue of the crankshaft 3 being mechanically driven, for example by virtue of the crankshaft 3 being driven with combustion engine action by way of the reciprocating-piston engine, or by virtue of the crankshaft 3 being driven by external action.

(57) The control unit 22 is interconnected with the crankshaft sensor 23 and with the variable outlet valve drive 24, and is designed, such that, in the electric-motor operating mode, the first outlet valve 25 is open in a position range 28 of the crankshaft 3 in which the first piston 27 is situated in a compression stroke 29, illustrated by the arrows 28 and 29 in FIG. 1c. The compression stroke in that position range 28 of the crankshaft 3 in which the first piston 27 performs a movement 29 from bottom dead center of the first piston 27, illustrated in FIG. 1c, in the direction of top dead center of the first piston 27, illustrated in FIG. 1d. A corresponding situation applies to the other pistons and to the outlet valves assigned thereto.

(58) By way of said measure, it is achieved that, in the electric-motor operating mode, no compression has to take place in the respective combustion chamber 26, and the drag torque of the reciprocating-piston engine can be reduced.

(59) The power control element 30 is electrically interconnected with the electrical energy store 21, with the first electromechanical converter 12a, with the second electromechanical converter 12b, with the third electromechanical converter 12c, with the fourth electromechanical converter 12d, and with each further electromechanical converter. The power control element 30 is furthermore designed such that, in the electric-motor operating mode, the crankshaft 3 can be driven with electric motor action with adjustable power by virtue of the electrical energy store 21 being discharged, and in the generator operating mode, the electrical energy store 21 can be charged with adjustable power by virtue of the crankshaft 3 being mechanically driven.

(60) The power control element 30 may be a functional constituent part of the control unit 22 and vice versa.

(61) The power control element 30 is electrically interconnected with the electrical energy store 21, with all of the electromechanical converters and with the crankshaft sensor 23, and designed, such that the power can be distributed to the electromechanical converter pairs 12a and 12b, 12c and 12d etc., which are assigned to in each case one piston, with different power fractions, such that the pistons can be assigned different levels of electrical power. The distribution of the power to the converter pairs 12a and 12b, 12c and 12d, etc., is performed in a manner dependent on the position of the crankshaft 3. In particular, the distribution of the power is performed in a manner dependent on the position of the crankshaft 3, in such a way that inertia forces and inertia torques of relatively high order, in particular of second order, arising as a result of the movement of the crankshaft 3, of all of the connecting rods and of all of the pistons, are reduced or compensated, as described in the introduction.

(62) FIGS. 2a and 2b illustrate a first alternative embodiment of the crankshaft 3. In this alternative embodiment, instead of the shape of a closed circular inner ring which surrounds the respective crank web 9a, 9b, 9c and 9d, as in the first embodiment of FIGS. 1a to 1j, all inner permanent magnet units 8a, 8b, 8c and 8d have the shape of a circular-arc-shaped inner ring section which surrounds the respective crank web. Said open ring section has a semicircular shape with a geometric first axis 15 which lies on the crankshaft axis 4. Thus, the circular-arc-shaped inner ring section has a first center angle of 180, as shown in FIGS. 2a and 2b. During rotation of the crankshaft 3, the inner permanent magnet units 8a and 8b circulate around the crankshaft axis 4 on geometric first circular paths 10a and 10b respectively, which are illustrated by way of dashed lines in FIG. 2a.

(63) FIGS. 3a to 3d show a second exemplary embodiment of the reciprocating-piston engine according to the invention with closed ring-shaped inner permanent magnet units 8a, 8b, 8c and 8d, and circular-arc-shaped outer coil units 11a, 11b, 11c and 11d.

(64) As is also the case in the preceding, first exemplary embodiment of FIGS. la to 1j, the inner magnetic field units are permanently magnetic and are in the form of first inner permanent magnet units 8a, 8b, 8c and 8d. The latter are each in the shape of a closed circular inner ring which surrounds the respective crank web.

(65) In this exemplary embodiment, too, the inner permanent magnet units 8a, 8b, 8c and 8d have first permanent magnets 16 which are arranged in a line with one another in a circle-circumferential direction in relation to the crankshaft axis 4, in such a way that the magnetic polarity of the first permanent magnets 16 alternates in the circle-circumferential direction, such that a magnetic alternating field is generated during rotation of the crankshaft 3. However, the orientation of the permanent magnets 16 differs in relation to the preceding exemplary embodiments. In this exemplary embodiment, the first permanent magnets are arranged adjacent to one another along the circular inner ring section and have alternating magnetic north poles N and south poles S pointing in a radial direction, as shown in FIG. 3c.

(66) The outer magnetic field units are electromagnetic and are in the form of outer coil units 11a, 11b, 11c and 11d. They have the shape of a circular-arc-shaped outer ring section which surrounds the respective circular path 10a and 10b of the inner permanent magnet units 8a and 8b with a radial spacing and which has a geometric second axis 18 which lies on the crankshaft axis 4, wherein the circular-arc-shaped outer ring section extends with a second center angle of 180, as shown in FIG. 3d.

(67) The outer coil units have a second coil 19b which extends in the circle-circumferential direction and the second ring-shaped coil axis 20b of which runs in the circle-circumferential direction, as shown in FIG. 3d. As is likewise shown in FIG. 3d, in each case two outer coil units 11a and 11b are assembled in one housing, wherein the respective second coils 19b of the two outer coil units 11a and 11b are formed by a common, assembled second coil 19b.

(68) The third exemplary embodiment of the reciprocating-piston engine according to the invention as illustrated in FIGS. 4a to 4d likewise has closed ring-shaped inner permanent magnet units 8a, 8b, 8c and 8d with the geometric first axis 15, but has closed ring-shaped outer coil units 11a, 11b, 11c and 11d.

(69) As in the second exemplary embodiment from FIGS. 3a to 3d, the inner permanent magnet units 8a, 8b, 8c and 8d have first permanent magnets 16 which are arranged in a line with one another in a circle-circumferential direction in relation to the crankshaft axis 4, in such a way that the magnetic polarity of the first permanent magnets 16 alternates in the circle-circumferential direction, such that a magnetic alternating field is generated during rotation of the crankshaft 3. The first permanent magnets 16 are arranged adjacent to one another along the circular inner ring section and have alternating magnetic north poles N and south poles S pointing in a radial direction, as shown in FIG. 4c.

(70) The outer coil units 11a, lib, 11c and 11d have the shape of a circular-arc-shaped outer ring section which surrounds the respective circular path 10a and 10b of the respective inner permanent magnet unit 8a, 8b, 8c and 8d with a radial spacing and which has a geometric second axis 18 which lies on the crankshaft axis 4, wherein the circular-arc-shaped outer ring section extends with a second center angle of 360, such that the outer coil units 11a, 11b, 11c and 11d have the shape of a closed circular outer ring which surrounds the respective circular path 10a and 10b of the respective inner magnetic field unit 8a, 8b, 8c and 8d with a radial spacing, as shown in FIGS. 4a and 4d.

(71) FIG. 4d illustrates the first outer coil units 11a in more detail. It has second coils 19a arranged in a line with one another in a circle-circumferential direction and the second coil axes 20a of which run radially in relation to the crankshaft axis 4, such that said second coil axes intersect at a common point which lies on the second axis 18, which coincides with the crankshaft axis 4.

(72) FIGS. 5a and 5b show a fourth exemplary embodiment of the reciprocating-piston engine according to the invention with closed ring-shaped inner permanent magnet units 8a, 8b, 8c and 8d and with closed ring-shaped outer coil units 11a, lib, 11c and 11d.

(73) As shown in FIG. 5b, the ring-shaped first outer coil unit 11a of the fourth exemplary embodiment has a second coil 19d with a second coil axis 20d which runs parallel to the crankshaft axis 4 and which lies on the second axis 18. Said second coil 19d fully surrounds the inner permanent magnet unit 8a. The other inner permanent magnet units and outer coil units are constructed in the same way as the first inner permanent magnet unit 8a and the first outer coil unit 11a respectively.

(74) The ring-shaped first outer coil unit 11a with the second coil 19d has a bracket 51 by way of which the first outer coil unit 11a is held directly on the bearing cover 49, which is fixed by way of bearing cover screws 50 to the cylinder block 1, as shown in FIGS. 5a and 5b.

(75) In the exemplary embodiments presented above, the inner magnetic field unit is formed in each case by an inner permanent magnet unit, and the outer magnetic field unit is formed in each case by an outer coil unit. It is however also possible for the inner magnetic field unit to be an inner coil unit and for the outer magnetic field unit to be an outer permanent magnet unit, as illustrated in FIG. 6, or an outer coil unit, corresponding to FIG. 7.

(76) FIG. 6 illustrates a second alternative embodiment in which the first inner magnetic field unit, which has the shape of a closed circular inner ring with a first axis 15 which lies on the crankshaft axis 4, is electromagnetic and is in the form of a first inner coil unit 34. The first inner coil unit 34 has first coils 35 which are arranged in a line with one another in a circle-circumferential direction in relation to the crankshaft axis 4 and the first coil axes 36 of which run radially in relation to the crankshaft axis 4.

(77) The first outer magnetic field unit has the shape of a closed circular outer ring with a second axis 18 which lies on the crankshaft axis 4, and said first outer magnetic field unit is permanently magnetic and is in the form of a first outer permanent magnet unit 37. The first outer permanent magnet unit 37 has second permanent magnets 43 which are arranged in a line with one another in a circle-circumferential direction in relation to the crankshaft axis 4, in such a way that the magnetic polarity of the second permanent magnets alternates in the circle-circumferential direction such that a magnetic alternating field is generated during rotation of the crankshaft 3. For this purpose, the second permanent magnets 43 are arranged adjacent to one another along the circular-arc-shaped inner ring section and have north poles N and south poles S of alternating polarity orientation pointing in a radial direction.

(78) FIGS. 7a and 7b show a third alternative embodiment of the inner and outer magnetic field units. Whereas it has previously been the case that either the inner or the outer magnetic field unit is formed by a permanent magnet unit, the third alternative embodiment provides that both units are coil units. In this way, the use of permanent magnets can be dispensed with entirely.

(79) As is also the case in the embodiment of FIG. 6, the first inner magnetic field unit has the shape of a closed circular inner ring with a first axis 15 which lies on the crankshaft axis 4. Furthermore, the first inner magnetic field unit is electromagnetic and is in the form of a first inner coil unit 34. The first inner coil unit 34 has first coils 35 which are arranged in a line with one another in a circle-circumferential direction in relation to the crankshaft axis 4 and the first coil axes 36 of which run radially in relation to the crankshaft axis 4 and intersect at the first axis 15.

(80) The first coils 35 are arranged and interconnected such that the magnetic polarity, that is to say the north poles N and south poles S, of the first coils 35 alternates in the circle-circumferential direction, such that a magnetic alternating field is generated during rotation of the crankshaft 3.

(81) The first outer coil unit 11a has the shape of a circular outer ring which surrounds the first inner coil unit 34 with a radial spacing and which has a geometric second axis 18 which lies on the crankshaft axis 4.

(82) The first outer coil unit 11a has second coils 19a which are arranged in a line with one another in a circle-circumferential direction and the second coil axes 20a of which run radially in relation to the crankshaft axis 4, such that said coil axes intersect at a common point which lies on the second axis 18, which coincides with the crankshaft axis 4.

(83) To supply a voltage to the first inner coil unit 34 such that the first coils 35 generate a magnetic alternating field in a circle-circumferential direction during rotation of the crankshaft 3, the first inner coil unit 34 has additional coils 38 which are electrically connected to the first coils 35. Here, each of the first coils 35 is assigned an additional coil 38. The additional coils 38, which are arranged in a line with one another in a circle-circumferential direction, have additional-coil axes 40 which run parallel to the crankshaft axis 4, as shown in FIGS. 7a and 7b.

(84) Electromagnetic lateral magnetic field units 39 are arranged in static fashion in the crank chamber 2 axially adjacent to the first circular path 10a of the first inner coil unit 34, wherein each additional coil is assigned an electromagnetic lateral magnetic field units 39. The arrangement in the crank chamber 2 is indicated schematically in FIG. 5a by way of the reference designation 39. The lateral coils 41, which are arranged in a line with one another in a circle-circumferential direction, have lateral-coil axes 42 which run parallel to the crankshaft axis 4. The additional coils 38 and the lateral magnetic field units 39 are arranged in axially opposed positions with respect to one another in relation to the crankshaft axis 4, and designed, such that, during rotation of the crankshaft 3 about the crankshaft axis 4, said additional coils and lateral magnetic field units together form an electrical generator for the supply of electrical voltage to the first coils 35. Thus, the first inner coil unit 34, when it rotates, forms a magnetic field for generating an induced voltage in the first outer coil unit 11a.

(85) According to the invention, the individual features of the illustrated exemplary embodiments and embodiments may be freely combined.