Internal combustion engine with an AC generator

Abstract

Internal combustion engine in a portable, hand-held power tool such as a chainsaw, cut-off saw, brush cutter, or blower, wherein the internal combustion engine (1) comprises a piston (6), a combustion chamber (5) with a spark plug (15), and a crankshaft (4) driven by the piston (6) and mounted in a crankcase (3), with an inlet (8) for combustion air and an outlet (9) for exhaust gases, a wheel body (50) rotating with the crankshaft (4), and an alternating current generator (16) driven by the crankshaft (4) which supplies an electrical load, wherein the alternating current generator (16) is arranged within the radial boundary of the wheel body (50) and outside the crankcase (3), wherein the stator (40) of the alternating current generator (16) is penetrated by the crankshaft (4), and the rotor (52) is non-rotatably connected to the wheel body (50).and wherein the rotor (52) is designed as a magnetic ring (30) covering the stator (40), characterized in that the magnetic ring (30) is surrounded by a magnetic return ring (32).

Description

[0001] The invention relates to an internal combustion engine in a portable, hand-held power tool, such as a chainsaw, an angle grinder, a brush cutter, a blower or the like, according to the preamble of claim 1.

[0002] A drive unit with a generator is known from US Patent 5,163,400 A. The top-shaped rotor of the drive unit sits on a drive shaft and is attached to a coupling via a bolted connection. Several magnets are arranged on the inside of the rotor. The stator is attached to the housing, with the rotor at least partially overlapping the stator.

[0003] German patent application DE 199 53 914 A1 shows a motor chainsaw with an internal combustion engine and a generator. The generator's flywheel can be designed as a fan wheel.

[0004] A drilling machine driven by an electric motor is known from publication WO 02 / 068235 A2. The stator of the electric motor comprises a housing, a magnetic ring, and magnets held in magnetic pockets.

[0005] In such internal combustion engines, it is known to use the alternating current generator as an energy source for operating the ignition as well as an energy source for electrical consumers, e.g. a carburetor heater, a handle heater for a chainsaw or the like.

[0006] The housings of portable, handheld power tools offer limited space for installing an AC generator. To provide sufficient power, the generator must be appropriately sized and powerful; it must also be considered that an AC generator in portable, handheld power tools is subject to considerable mechanical stresses, such as vibrations. Furthermore, the generator's thermal management must be appropriately designed to prevent damage to the generator itself and / or its surroundings.

[0007] The invention is based on the objective of providing an internal combustion engine with an alternating current generator that requires little installation space, provides sufficient electrical power and withstands mechanical and thermal stresses over a long operating period.

[0008] The problem is solved according to the invention according to the characterizing features of claim 1.

[0009] The AC generator is located within the radial boundaries of the wheel body and outside the crankcase. This allows the generator to partially project into or be integrated into the crankcase and / or the wheel body. The stator, which typically contains a vertical induction coil, is penetrated by the crankshaft, while the rotor is fixed to the wheel body. Due to the generator's position between the crankcase and the wheel body, it is mechanically protected against damage and contamination. By appropriately designing the crankcase and modifying the wheel body that rotates with the crankshaft, the AC generator can be accommodated in the resulting space without significantly increasing the overall length in the crankshaft direction.

[0010] The wheel body rotating with the crankshaft can, for example, be the part of a coupling that is fixedly connected to the crankshaft and drives a tool from the internal combustion engine. Advantageously, the wheel body is formed by a fan wheel that supplies cooling air to the internal combustion engine. This fan wheel carries the rotor on its side facing the crankcase, with the rotor being expediently integrated into the fan wheel body. The integration can be so extensive that the stator lies essentially within the outer contour of the wheel body, meaning the fan wheel body completely encompasses the rotor.

[0011] The magnets of the magnetic ring are conveniently located in recesses within the wheel body itself and are advantageously secured against falling out of these recesses by gluing or clamping. To improve the magnetic flux, the rotor's magnetic ring features an external return ring. Alternatively, a single magnet could be used instead of the magnetic ring.

[0012] The stator is essentially formed by a coil former enclosed by a stator yoke with poles located on the outer circumference of the coil former. The stator yoke consists of at least two thin laminations, one on one end face of the coil former and the other on the opposite end face. The poles of the stator laminations interlock in a comb-like fashion with spacing between them and are located on the outer circumference of the coil former, while the laminations on the inner circumference of the coil former interlock in a flux-conducting manner. Preferably, the stator laminations on the inner circumference of the coil former are positively or frictionally connected to each other and / or to the coil former, e.g., by clipping. To prevent unwanted leakage flux between the interlocking laminations, the distance between adjacent laminations is greater than 2 mm, preferably greater than 3 mm.To achieve sufficiently high power output at low speeds of approximately 300 rpm while simultaneously minimizing heat generation at high speeds of approximately 15,000 rpm, the stator lamination is chosen to be approximately ≤ 1 mm thick. Advantageously, the stator lamination is made of electrical steel. Electrical steel has the beneficial property of reducing harmful eddy currents due to its high electrical resistance, while still conducting magnetic flux effectively. This results in a compact claw-pole generator with a stationary coil, capable of a high speed range from 300 rpm to 15,000 rpm without overheating. The claw-pole generator provides power outputs of 2 to 20 watts at low speeds and between 40 and approximately 200 watts at high speeds.

[0013] To provide sufficient electrical power, the distance between two adjacent poles is designed to correspond to the nth part of a crankshaft revolution, where n is an integer between 6 and 24. An advantageous design is achieved when the stator has twelve poles evenly distributed around the circumference of the coil former, with six poles assigned to the stator lamination of one end face and six poles to the stator lamination of the other end face. Such generators exhibit power outputs between 2 and 200 watts.

[0014] The AC generator serves not only as a power source but also as an ignition timing sensor. For this purpose, the signals from the AC generator are electronically evaluated, as the AC voltage signal contains characteristic features that indicate the crankshaft's rotational position. When a characteristic feature is detected, the current rotational position of the crankshaft can be correlated with the corresponding crankshaft angle of that feature, allowing ignition to occur according to the crankshaft angle without the need for separate rotational angle sensors.

[0015] In an advantageous embodiment of the invention, the AC generator, preferably designed as a claw-pole generator, star generator, or the like, is configured as a starter motor to start the internal combustion engine or at least to assist the starting process. Advantageously, the AC generator is configured in a first operating state as an energy source and / or signal transmitter, such as an ignition timing sensor, and in a second operating state as a starter motor. In the second operating state, the system can be powered by an energy source—for example, an internal or external starter battery. A starter battery can then be charged by the AC generator in its first operating state.

[0016] In the application, the term "alternating current generator" is to be understood generally, such that the alternating current generator – through appropriately modified wiring – can also be used as a starter motor. An alternating current generator that can also be used as a starter motor can also be generally referred to as an alternating current machine.

[0017] Further features of the invention will become apparent from the further claims, the description, and the drawing, in which exemplary embodiments of the invention are described in detail below. The drawing shows: Fig. 1 in schematic representation an internal combustion engine with an alternating current generator, Fig. 2 in schematic representation the structure of an internal combustion engine according to Fig. 1 arranged alternating current generator, Fig. 3 an exploded view of the stator of the AC generator according to Fig. 2, Fig. 4 a front view of the stator Fig. 2, Fig. 5 a cut along line VV in Fig. 4, Fig. 6 a cross-section through the internal combustion engine Fig. 1 with stator attached to the crankcase, Fig. 7 in enlarged view the section through the alternating current generator arranged on the internal combustion engine, Fig. 8 An enlarged view of the mounting of the stator to the crankcase of the internal combustion engine, Fig. 9 an idealized representation of the voltage curve of the AC generator, Fig. 10 a schematic representation of the structure of the rotor as an integrated component in the blower wheel of the cooling air blower, Fig. 11 a view of the blower wheel after Fig. 9 with integrated rotor of the AC generator, Fig. 12 a view of a blower wheel with integrated rotor and magnets held in mounting pockets of the blower wheel, Fig. 13 a view of the rear of a blower wheel with integrated rotor and arranged magnetic backing ring, Fig. 14 a view of the back of a blower wheel with individual magnets clamped in mounting pockets, Fig. 15 an exploded view of a further embodiment of a stator of the AC generator provided with mounting lugs, Fig. 16 a view of the stator after Fig. 15 in assembled state, Fig. 17 a front view of the stator after Fig. 16, Fig. 18 a cut along the line XVIII-XVIII in Fig. 17, Fig. 19 an exploded view of another embodiment of a stator with a laminated yoke, Fig. 20 a view of the stator after Fig. 19 in assembled state, Fig. 21 a front view of the stator after Fig. 20, Fig. 22 a cut along the line XXII-XXII in Fig. 21, Fig. 23 an exploded view of another embodiment of a stator with a laminated yoke, Fig. 24 a view of the stator after Fig. 23 in assembled state, Fig. 25 a front view of the stator after Fig. 24, Fig. 26 a cut along the line XXVI-XXVI in Fig. 25, Fig. 27 a circumferential section of a stator with a top view of specially designed claw poles, Fig. 28 a voltage curve of the induced voltage of an alternating current generator with a claw design according to Fig. 27, Fig. 29 an embodiment of a design of a magnet ring of the rotor, Fig. 30 a view of a base plate for mounting a stator with mounting tabs according to Fig. 16 or Fig. 20, Fig. 31 a section through a base plate for mounting a stator with a clamping part, Fig. 32 in enlarged view a clamping part for clipping into the holder according to Fig. 31, Fig. 33 in schematic representation a wedge connection between a base plate and a stator, Fig. 34 in schematic representation an alternating current generator with a two-pole stator, Fig. 35 a view of the stator after Fig. 34, Fig. 36 a section along the line XXIX-XXIX in Fig. 35, Fig. 37 a perspective view of a coil carrier with a wound coil, Fig. 38 a perspective view of a stator according to Fig. 37 with connection for a signal line, Fig. 39 a stator according to Fig. 38 with connected signal line, Fig. 40 in perspective view a coil body with electrical connecting part held on the coil body, Fig. 41 in perspective view the coil body after Fig. 40 with signal line connected to the coil, Fig. 42 in perspective view a coil former with wound coil and a coil end wound onto a mandrel using wire-wrap technique, as well as a signal line with a socket, Fig. 43 the coil body Fig. 42 with socket mounted on the mandrel, Fig. 44 the coil body after Fig. 43 with stator laminations securing the socket, Fig. 45 a schematic representation of an alternating current generator designed as a star generator.

[0018] In the schematic representation in Fig. Figure 1 shows an internal combustion engine, which in this exemplary embodiment is designed as a two-stroke engine. However, the invention is not limited to use with single- or multi-cylinder two-stroke engines; it can also be used with single- or multi-cylinder four-stroke engines or other engines such as rotary engines. Such engines, in particular reciprocating piston engines, are used as drive motors in modern power tools such as chainsaws, cut-off saws, brush cutters, blowers, and the like.

[0019] The internal combustion engine 1 comprises a cylinder 2 with a crankcase 3 in which a crankshaft 4 is rotatably mounted. A combustion chamber 5 is formed in the cylinder 2, which is bounded by a reciprocating piston 6. The piston 6 is connected to the crankshaft 4 in the crankcase 3 via a connecting rod 7 and drives the crankshaft by rotating it. In the illustrated embodiment, an intake port 8 for combustion air and / or mixture opens into the combustion chamber 5, the intake port 8 being located at the end of a transfer port 14 in the cylinder wall. The other end of the transfer port 14 is open towards the crankcase 3. Furthermore, an exhaust port 9 is provided through which combustion gases are discharged from the combustion chamber 5.

[0020] A fuel / air mixture is supplied to the internal combustion engine 1 via a carburetor 10, with the mixture inlet 11 opening into the crankcase 3. Combustion air is drawn in through an air filter 12 and supplied to the mixture inlet 11 via the intake manifold 13 and the carburetor 10. As the piston 6 moves upwards, the mixture is drawn into the crankcase 3 through the mixture inlet 11 due to the vacuum created in the crankcase 3. As the piston 6 moves downwards, the mixture drawn into the crankcase 3 is guided through the transfer port 14 to the intake port 8 and flows into the combustion chamber 5. As the piston continues its upward movement, the intake port 8 and the exhaust port 9 close, thus compressing the mixture present in the combustion chamber 5. The compressed mixture is ignited by a spark plug 15. The expanding combustion gases drive the piston 6 downwards, whereby the outlet 9 is opened and the combustion gases can flow out.The amount of combustion air flowing in is controlled by a pivotable throttle valve 10a in the carburetor 10.

[0021] In the illustrated embodiment, a fan wheel 51 for the cooling air supply and an AC generator 16 are driven by the crankshaft 4, the induced voltage signals of the generator 16 being supplied to an ignition unit 18 via a line 17. The ignition unit 18 is connected to the spark plug 15 via a high-voltage cable 25. The high-voltage cable 25 and the electrical line 17 are sufficient as a connection between the engine 1 and the ignition unit 18 for its operation.

[0022] The alternating current generator 16 provided on the internal combustion engine 1 is advantageously designed in a first embodiment as a so-called claw pole generator, as it is in Fig. Figure 2 is schematically depicted in exploded view. Generally, this can be described as an AC machine that operates in one mode as a generator and, in a preferred design, has, for example, the structure of a claw-pole generator. The generator 16 can be used to supply electrical loads, such as a carburetor heater 96, which is connected to the ignition unit 18 via a cable 95. The energy of the AC voltage signal can also be used for other internal and external loads, including charging a battery that, for example, powers the ignition or an electric or electromagnetic starter. The AC voltage signal can be processed in the ignition unit 18 if required.

[0023] In an advantageous embodiment, the AC generator 16 is designed and wired such that it can also operate as a starter motor in another operating mode. The AC generator 16 operating as a starter motor can serve solely to start the internal combustion engine 1 or assist the starting process, e.g., together with a recoil starter. Preferably, the AC generator 16 is designed such that, in one operating state, it can start the internal combustion engine 1 without any external assistance. In the other operating state, switched by a switching unit 77, the generator 16 is then used as a power source and / or signal source, e.g., to supply the ignition unit 18 via line 17 and to output an ignition timing signal. The AC generator 16 is thus simultaneously a power source, ignition timing sensor, signal generator, sensor, and starter motor, depending on the operating state it is switched to by the switching unit 77.When used as a starter motor, the generator 16 is powered by an energy source 78, which can be a rechargeable starter battery and also provides the necessary energy for ignition during starting. The energy source 78 can be connected to the generator via the switching unit 78 and the line 76.

[0024] It can be advantageous to arrange the ignition unit 18 separately from the generator 16 at a thermally advantageous location. For example, due to its design, the ignition unit 18 can be positioned on the underside of the crankcase 3, so that it is located away from the cylinder 2. An arrangement within the installation space of the claw-pole generator 16 between the crankcase 3 and the wheel body 50 is also suitable. To keep the length of the high-voltage cable to the spark plug 15 short, a high-voltage unit can be arranged separately from the ignition unit 18 near the spark plug or even integrated into it.

[0025] The generator 16 essentially consists of a housing-mounted coil former 20, which can be fixed to the crankcase 3 of the internal combustion engine by means of mounting screws. The mounting screws protrude through mounting openings 23 in the stator 40, with the coil former 20 having a sheet metal plate 41 on each of its end faces, the poles 42 of which overlap the outer circumference 21 of the coil former 20. The design is advantageously similar to that of a claw-pole generator. Thus, in the exemplary embodiment according to Fig. Two of the twelve claws 42 engage the coil 22, with the claws 42 alternately engaging the coil 22 from one and then the other end face. The claws form poles 42 of a magnetic circuit for alternating magnetic flux. An O-ring 29 is advantageously located between the claws 42 and the coil 22, sealing the circumferential groove.

[0026] The division of the circumference into an integer number of poles / claws 42 is carried out with the intention of inducing a meaningful alternating voltage signal. Subsequently, an alternating voltage signal with several periods is to be generated over one crankshaft revolution. Advantageously, one crankshaft revolution is divided into n periods T, where n is greater than two and has a maximum value of twelve. Advantageously, n is an integer between 4 and 8, particularly between 5 and 7. In the exemplary embodiment, n is chosen to be six, so that a continuous alternating voltage signal with six full waves or 12 half waves is generated, as shown. Fig. Figure 9 shows the design relationship between stator 40 and rotor 52. The arrangement of these elements can be advantageously chosen such that the top dead center (TDC) of the piston is close to, and preferably at, the maximum of a half-shaft. The rotational position is expediently such that a zero crossing O ipreferably at approximately 15° crankshaft angle before top dead center (TDC). Accordingly, bottom dead center of the piston is at approximately 195° crankshaft angle.

[0027] The exact structure of the stator results from the Fig. 3, Fig. 4 to Fig. 5. The coil former 20 is a molded body, preferably made of plastic, which has an outer circumferential groove for receiving the coil 22 or several coils. In the exemplary embodiment, the coil 22 wound in the circumferential groove is gripped by several claws 42 forming magnetic poles, the claws 42 being mechanically separated from one another in the circumferential direction. Preferably, the distance between adjacent claws 42 is more than 2 mm, particularly more than 3 mm. A stator lamination 41 is provided on each end face of the coil former 20, each stator lamination 41 gripping the coil 22 with six claws in the illustrated exemplary embodiment. The circumferential distance U between two adjacent claws is – as shown Fig. Figure 4 shows -30° KW, so that twelve claws 42 are provided as magnetic poles around the circumference of the stator 40. Six poles project from each stator lamination over the coil, so that in the circumferential direction the poles alternately correspond to one stator lamination on one end face or the other stator lamination on the other end face. The stator laminations 41 consist of a magnetically suitable thin sheet, in particular a sheet of approximately ≤ 1 mm thickness. Electrical steel is particularly suitable for this purpose.

[0028] To attach the assembled stator after Fig. 4. Through holes 23 are provided in the coil former 20 and the respective stator laminations 41, which in one embodiment ( Fig. 2, Fig. 4, Fig. 5) are located on the radial inner circumference 43 of the coil former 20. The mounting holes 23 penetrate the coil former radially within the coil 22, so that a rotor 52 encompassing the stator 40 is not obstructed by mounting means. It may also be advantageous to arrange the mounting holes 23 on the radial outer circumference, so that the coil 22 lies within the mounting holes 23.

[0029] The two laminations 41 forming the stator yoke interlock at the inner circumference of the coil former 20 in a flux-conducting manner. Preferably, the stator laminations 41 are positively or frictionally connected to each other and / or to the coil former 20 at the inner circumference 43 of the coil former 20, in particular by clips. Radially inner tabs 44 of one lamination 41 engage in corresponding recesses 45 of the other lamination 41. The fastening screws 25, which pass through the mounting holes 23 for housing-fixed mounting of the stator 40, additionally secure the stator 40, so that axial separation is prevented even under mechanical or electrical load.

[0030] To reduce stray flux, the area of ​​the stator lamination 41 between two claws 42 can be suitably shaped, for example rounded, as shown in Fig. 4 shown with dashed lines.

[0031] How Fig. Figure 2 shows that a magnet ring 30 made of individual permanent magnets 31 is associated with the housing-mounted stator 40, the permanent magnets 31 being distributed around the circumference with alternating polarities. In the illustrated embodiment, twelve permanent magnets 31 are provided, corresponding to the number of claws or poles 42 on the stator 40. The permanent magnets 31 are arranged circumferentially at an angular distance of 30° KW from each other.

[0032] In one embodiment, the permanent magnets 31 are arranged in a wheel body 50 designed as a blower wheel 51, which is mounted non-rotatably on the crankshaft 4. The wheel body 50 is in Fig. 1 is schematically represented as a dotted circle.

[0033] The wheel body 50 of the blower wheel 51 is preferably located in receiving pockets 53 ( Fig. 12) The held magnets 31 are surrounded by a magnetic return ring 32 to enhance their magnetic effect.

[0034] As the Fig. 6, Fig. 7 to Fig. As shown in Figure 8, the AC generator 16, advantageously designed as a claw-pole generator in the exemplary embodiment, is arranged in the region of an end face 24 of the crankshaft 4 between the crankcase 3 and the wheel body 50. The rotor 52 is part of a coupling via which a tool of a work device is driven by the crankshaft. Such a work device is, for example, an angle grinder. The stator 40 of the AC generator 16 is penetrated by the end 24 of the crankshaft 4, with the rotor 52 of the coupling being attached to the end 24. In the illustrated exemplary embodiment according to the Fig. 6, Fig. 7 to Fig. 8 The stator 40 is fixed to the crankcase 4 by means of fastening screws 25, for which purpose a mounting boss 26 is expediently formed on the crankcase 4, on the end face 27 of which a sheet 41 of the stator yoke rests. This not only achieves good mechanical support, but also establishes an electrical ground connection. The coil 22 is advantageously connected at one end to the stator sheet 41, so that an electrical ground connection to the coil is established.

[0035] In the exemplary embodiment according to the Fig. 6, Fig. 7 to Fig. Figure 8 shows that the stator 40 and the rotor 52 are arranged such that the stator 40 lies completely within the outer contour of the wheel body 50. The axial position of the wheel body 50 can be adjusted by means of appropriately thick washers 28 on the end 24 of the crankshaft.

[0036] The position of the stator 40 between the wheel body 50 and the crankcase 3 protects the AC generator 16 against contamination and mechanical damage. The flat contact surface on the end faces 27 of the mounting bosses 26 not only ensures a good ground connection but also guarantees good heat transfer to the crankcase 3, thus preventing overheating of the induction coil 22 or the induction coils.

[0037] When the crankshaft rotates, the magnet ring 30 of the rotor 52 rotates around the claws or poles 42 of the stator 40, whereby the AC generator 16 produces a sinusoidal alternating signal according to the idealized normalized representation in Fig. 9 outputs. The assignment of rotor 52 and stator 40 of the AC generator 16 is such that a zero crossing O occurs shortly before the top dead center TDC of the piston. i located in Fig. 9. The top dead center (TDC) of the piston is located at approximately 15° crankshaft angle after a zero crossing. i ; accordingly, the bottom dead center (BDC) of the piston is at approximately 195° crankshaft angle.

[0038] The number of poles 42 or claws of a stator 40 is selected such that the distance between two adjacent poles corresponds to the nth part of a crankshaft revolution. n is advantageously an integer between 6 and 24. In the exemplary embodiment, n is chosen to be 12, so that the stator 40 has twelve poles 42 evenly distributed around the circumference of the coil former 20.

[0039] Due to the twelve poles 42 and the corresponding number of twelve permanent magnets 31 of the magnet ring 30, which lie next to each other around the circumference with alternating polarity, the signal pattern results when the rotor 52 is rotated according to Fig. 9. The distance between two zero crossings O i and O i+1This corresponds exactly to the 30° crank angle of the design of the stator 40 and the rotor 52. Over one crankshaft revolution of 360° crankshaft, twelve zero crossings O1 to O12 of the signal S are obtained. The time t between two zero crossings Oi depends on the rotational speed of the crankshaft 4, so that time t is a measure of the rotational speed of the crankshaft 4. In each zero interval N i By determining the time t and the known design of the stator (30° crank angle spacing of poles 42), the current rotational speed can be determined for each zero interval N1 to N12. The AC voltage signal S thus consists of six periods I to VI of period T.

[0040] If the AC generator 16 according to the invention is not only used as an energy source but also as an ignition angle sensor, it may be advantageous to provide the housing-fixed rotational position of the stator 40 on the crankcase 3 such that the top dead center TDC of the piston 6 lies, for example, at a maximum of the half-shaft or about 15° KW after a zero crossing O i of the voltage signal S. A constructive orientation of the stator 40 such that the top dead center of the piston 6 is in the middle between two zero crossings O i If the signal lies, for example, in the region of the maximum of the half-wave, the evaluation of the AC voltage signal S as an ignition angle signal can be simplified. To find a zero crossing O i To detect the induced alternating voltage signal S with minimal error, it is planned to measure the current flow through any electrical load approximately 5° KW before an expected zero crossing O. i to approximately 1° KW after this zero crossing O ito prevent, for example, switching off, i.e., performing zero point detection with generator 16 unloaded.

[0041] In Fig. Figure 10 shows a schematic diagram of the integration of the magnet ring 30 of the rotor 52 into the wheel body 50 of the fan wheel 51. Advantageously, the permanent magnets 31, which are arranged next to each other with alternating polarity, are inserted into a common retaining ring 33, which is preferably made of plastic. The retaining ring 33 has individual receiving pockets 34 that are open towards the base 54 of the wheel body 50. The retaining ring 33, fitted with the permanent magnets 31, is inserted axially into the receiving cup 55 of the wheel body 50. Advantageously, the retaining ring 33 is fixed in the receiving cup 55 by retaining tabs, by gluing, or the like.

[0042] In Fig. 11 is an order according to Fig. Figure 10 shows the assembled state. The receiving cup 55 is designed as a central recess in the wheel body 50 of the blower wheel 51, with the retaining ring 33 being received in the contour of the wheel body 50 over part of its axial height. In the embodiment according to Fig. 11 A magnetic return ring 32 is arranged to increase the magnetic flux and is held in the receiving pot 55 in a suitable manner to prevent rotation. The return ring 32 has clamping tabs 35 that are bent over the retaining ring 33 and secure it in its position in the receiving pot 55.

[0043] In the Fig. 12, Fig. 13 to Fig. Figure 14 shows further embodiments of the integration of the rotor 52 into a wheel body 50 of a blower wheel 51.

[0044] In the exemplary embodiment according to Fig. 12 The rim of the receiving pot 55 is so thickly formed that individual receiving pockets 53 for inserting the permanent magnets 31 are formed in this wall 56. The spacing A of the permanent magnets 31 corresponds to 30° KW; the twelve arranged permanent magnets 31 are evenly distributed in corresponding receiving pockets 53 around the circumference of the receiving pot 55. The inner diameter D i The receiving pot 55 is designed such that an associated stator 40 is engaged without collision. The arrangement is such that the gap between the outer circumference 21 of the stator 40 and the inner circumference of the receiving pot 55 is minimized to ensure good magnetic interaction between the permanent magnets 31 and the claws 42 of the stator yoke.

[0045] The permanent magnets 31 inserted into the receiving pockets 53 are mechanically held in place by means of slightly undersized receiving pockets 53. This clamps the permanent magnets 31 into their receiving pockets 53; for added security, adhesive can be applied to designated cavities 57 in each receiving pocket 53.

[0046] In the exemplary embodiment according to Fig. The receiving pockets 53 are open both radially inwards and radially outwards. The receiving pockets 53 are closed by a magnetic return ring 32, which allows for improved magnetic flux. The return ring 32 also secures the individual magnets due to magnetic forces; advantageously, the individual magnets are also potted, glued, or otherwise held in their receiving pockets 53.

[0047] In the exemplary embodiment according to Fig. 14 The receiving pockets 53 are designed with an oversize dimension; plastic strips 58 are inserted laterally to clamp the permanent magnets 31 in the receiving pockets 53. The strips 58 can also be made of a suitable material other than plastic. Otherwise, the structure corresponds to Fig. 14 according to Fig. 12.

[0048] The in the Fig. 15, Fig. 16, Fig. 17 to Fig. The embodiment of a stator 40 for a claw pole generator shown in Figure 18 is fundamentally the same in construction as the stator according to the Fig. 3, Fig. 4 to Fig. 5. However, for the attachment of the stator 40, the following differ from the stator 40 according to the Fig. 3, Fig. 4 to Fig. Five mounting tabs 46 are integrally formed on the coil former 22. The mounting tabs 46 extend radially and, in particular, also axially outwards from the coil former 22 beyond the outer circumference 47 of the stator 40. The stator laminations 41 are designed such that the mounting tabs 46 project through a recess 48 in the associated stator lamination 41.

[0049] A preferably one-piece connection of the tabs 46 to the spool body 20 is shown in section according to Fig. 18 clearly visible.

[0050] The exemplary embodiment according to the Fig. 19, Fig. 20, Fig. 21 to Fig. 22 corresponds in its basic structure to the stator 40 according to the embodiment shown in the Fig. 15, Fig. 16, Fig. 17 to Fig. 18. In a deviation from the above, the stator yoke is not formed from just two interlocking stator laminations 41, but from a total of six stator laminations 41a, 41b, and 41c. Each pole 42 consists of three claws 42a, 42b, and 42c, which lie side by side and one above the other. This laminated construction reduces the eddy currents in the stator yoke and thus leads to lower heat loss.

[0051] Due to the laminated design, the coil former is made 20 narrower so that the axial installation space corresponds approximately to that of a two-laminated stator according to the Fig. 16, Fig. 17 to Fig. 18 is given.

[0052] The embodiment according to the Fig. 23, Fig. 24, Fig. 25 to Fig. 26 corresponds in its basic structure to the stator 40 according to the embodiment shown in the Fig. 15, Fig. 16, Fig. 17 to Fig. 18. In contrast, the stator yoke is constructed of laminates and consists of four interlocking stator laminations 41a and 41b. Each pole 42 is composed of two claws 42a and 42b, which lie one on top of the other. This laminated construction reduces the eddy currents in the stator yoke and thus leads to lower heat loss.

[0053] For fastening the stator 40, external, radially projecting mounting tabs 46 are provided, each having a mounting opening for receiving a fastening screw. The mounting tabs 46 lie in a common plane that is approximately parallel to the crankcase wall. This allows the stator 40 to be easily screwed in axially.

[0054] In order to be able to determine the direction of rotation of the generator 16 from the alternating voltage signal without great effort, the claws 42 are designed asymmetrically to the direction of rotation. Fig. Figure 27 shows the asymmetrical shape of the claw 42 in a top view, which imposes a specific shape on the induced alternating voltage signal S. This shape of the signal is in Fig. Figure 28 illustrates this. The gently rising flank 42.10 is caused by the slope 42.1 of the claw 42, while the steeper falling flank 42.20 is caused by the steep edge 42.2 of the claw 42. In one direction of rotation, the half-wave thus always begins with a gently rising flank 42.10; if the direction of rotation is reversed, a half-wave would begin with the steep flank 42.20. The slope of the half-wave thus allows the direction of rotation to be determined.

[0055] In Fig. Figure 29 shows an alternative magnetic ring. Permanent magnets 31 are clamped into adjacent slots 31.1 of a magnetically conductive, in particular stamped, sheet metal ring 30.1 such that like poles N, S are opposite each other in the circumferential direction. This creates a corresponding magnetic pole N or S between two slots 31.1 on the inner circumference of the sheet metal ring 30.1. The inner diameter of the magnetic ring 30 can thus be easily determined by a manufacturing tool, resulting in a high moment of inertia for the magnetic ring 30.

[0056] In order to securely fix a stator 40 with mounting tabs 46 to the crankcase 3, a mounting plate 60 is required according to Fig. 30. The mounting plate 60 can be integrated into the wall of the crankcase 3, or corresponding mounting bosses 61 can be formed in the wall of the crankcase 3. The contact surface 67 of the mounting bosses 61 is adapted to the angular position of the mounting tabs 46. The design of the mounting tabs 46 ensures that the stator 40 is deeply inserted into the rotor 52 without the mounting tabs 46 colliding with the edge 59 of the rotor 52. A cylindrical projection 62 is provided for centering the stator, onto which the stator is slid.

[0057] The Fig. 31 and Fig. Figure 32 shows an alternative embodiment of a stator mounting. Fig. Figure 31 shows a section of a cylinder extension 62, which can be attached to a mounting plate 63 or integrally formed directly on the wall of a crankcase 3. The outer diameter D aThe cylinder extension 62 corresponds to the inner diameter d i ( Fig. 21) of the stator 40 adapted so that the stator 40 is essentially radially free of play on the cylindrical extension 62.

[0058] A clip nut 64 is used as a locking element according to Fig. 32 is provided, which engages with its clip tongues 65 in the cylinder extension 62 and locks there. The clip nut 64 thus axially secures a stator mounted on the cylinder extension 62. Advantageously, a stop in the circumferential direction is provided for rotationally fixed mounting. In general, it is advantageous to fix the stator to a component such as the crankcase with a snap-fit ​​connection such as an advantageous clip fastening.

[0059] In the exemplary embodiment according to Fig. 33 The stator 40 is potted with a potting compound, in particular with plastic. During potting, circumferential wedges 49a are formed on the inner circumference, which correspond to a wedge geometry on a cylindrical extension 62a. The stator 40 is axially pushed onto the cylindrical extension 62a and then rotated until the circumferential wedges 49a engage with the circumferential wedges 49b of the cylindrical extension in a clamping manner. The stator 40 is held on the cylindrical extension 62a, in particular by a self-locking frictional connection. For rotationally fixed fastening, a locking pin 66 is advantageously screwed in, the tip of which penetrates radially into the cylindrical extension 62a. In this way, easy mounting, e.g., on the wall of the crankcase 3, is possible. The cylindrical extension 62a is advantageously cast in place.

[0060] In the exemplary embodiment according to the Fig. 34, Fig. 35 to Fig. In section 36, the stator 40 is reduced to a stator yoke 70, which extends circumferentially over an nth part of a crankshaft revolution. The stator yoke 70 extends over such a circumferential angle that two magnets 31 of the magnet ring 30 can induce a magnetic flux in the stator yoke 70. Since the magnet ring 30 has twelve permanent magnets 31 arranged at equal intervals circumferentially, the distance between adjacent permanent magnets 31 is 30° crankshaft angle; it is therefore sufficient if the stator yoke extends circumferentially over at least 30° crankshaft angle. The coil former is penetrated by the stator yoke 70, as shown by the Fig. 35 and Fig. Show 36. From Fig. Figure 36 further clarifies that the stator yoke 70 is constructed of laminated material, i.e., it consists of individual stator laminations 71. The coil former 72 surrounds the stator laminations and houses an induction coil in which, when the magnetic ring 30 rotates, a voltage is induced due to the changing magnetic flux, corresponding to the idealized alternating voltage signal S in Fig. 9 corresponds.

[0061] In addition to the structural design of the stator and rotor, a mechanically robust and reliable electrical connection for the signal line is necessary to carry the AC voltage signal S from the induction coil. In the exemplary embodiment according to the Fig. 37, Fig. 38 to Fig. 39 A receptacle 80 for a metallic hollow rivet 81 is provided in the coil former 20. The wire of the coil end 82 is stripped and placed under the hollow rivet 81, which is then riveted firmly into the coil former. This creates an electrical connection between the wire of the coil and the electrically conductive hollow rivet 81, which in turn is held in the electrically insulating coil former 20. The coil former 20 is expediently made of plastic.

[0062] After the stator laminations 41 are arranged, one of which has a corresponding recess 83 around the area of ​​the hollow rivet 81, an electrical signal line 17 is threaded through the hollow rivet 81. The signal line 17 has an electrically conductive plug 84 at its far end, which is connected to the line 17 and comes to rest in the hollow rivet 81 ( Fig. 39). The plug 84 in the hollow rivet 81 establishes the electrically conductive connection of the coil end 82 with the signal line 17 according to the principle of a plug.

[0063] In the exemplary embodiment according to the Fig. 40 and Fig. 41 An electrical connecting element 85 is held in the material of the coil former 20 at the edge of the coil former 20, advantageously in the circumferential direction between two claws of a stator lamination. The connecting element 85 is advantageously designed as a crimp connector 86, into which, on the one hand, the end 82 of the coil and, on the other hand, the end 17a of the signal line 17 are inserted. Once the two bare wire ends are inserted, - as Fig. 41 shows - the crimp connector 86 is crimped, so that a mechanically firm, electrically conductive connection is made between the end 82 of the coil and the signal line 17.

[0064] In the exemplary embodiment according to the Fig. 42, Fig. 43 to Fig. 44 A type of wire-wrap technique is used to connect the coil 22 to the signal line 17. The end 82 of the coil 22 is wound onto a mandrel 87, which is held in the coil former 20 and extends axially from its end face. The mandrel 87 can be formed integrally with the coil former 20. A socket 88 is associated with the mandrel 87 and is electrically connected to one end 17a of the signal line 17. The socket 88 is placed onto the mandrel 87 ( Fig. 43), wherein the plug contacts 89 electrically contact the end 82 of the coil wire.

[0065] The socket 88, mounted on the mandrel 87, rests with lateral locking tabs 90 in corresponding receptacles 20a and 20b of the coil former 20, which extend circumferentially to the right and left of the mandrel 87. When the stator laminations 41 are fitted, the claw sections engage the tabs 90 in the receptacles 20a and 20b, so that the socket 88 is positively secured to the stator 40.

[0066] In the exemplary embodiment according to Fig. In the embodiment 45, the AC generator 16 is configured as a star generator, i.e., as a generator 16 with radially star-shaped poles 42. The coil former 20 of the stator 40 consists of a stack of individual laminations 41a, the individual laminations 41a being axially stacked on top of each other. The lamination stack has individual, post-like coil supports that extend radially inwards to an outer circumference 21. The posts form poles 42a and serve as supports for induction coils 22, at least one of which is arranged on each post-like pole 42a. In the illustrated embodiment, a total of 12 posts are provided, spaced apart from each other in the circumferential direction at an equal distance U, preferably 30°.

[0067] To secure the stator 40, through axial mounting openings 23 are provided in two approximately opposing posts. These openings penetrate the laminations 41a and serve to accommodate mounting screws with which the stator 40 is fixed against rotation – e.g., to the crankcase. The posts with the mounting openings 23 are designed without a coil.

[0068] The rotor 40 is advantageously cast in place, for which purpose a cylindrical base plate 36 is placed at the base of the post-like poles 42a, projecting axially beyond the end faces of the lamination stack. Correspondingly, the posts carry end plates 37 at their free ends, the axial length of which corresponds to the axial height of the base plate 36. The space between the base plate 36 and the end plates 37 is filled with casting resin or the like. This fixes the coils to the individual post-like poles 42a and secures them against mechanical damage.

[0069] The posts with the mounting openings 23 are selected such that, in the circumferential direction, four poles 42a are located between them on one side and six poles 42a on the other side. The sum signal of the interconnected coils 22 corresponds to the alternating signal S as described in Fig. 9 is shown.

[0070] The rotor 52 is formed – as in the previous embodiments – by a wheel body 50, which in this embodiment forms the fan wheel 51 of an internal combustion engine. A receiving cup 55 is formed on the side facing the stator 40, as described in the Fig. 11, Fig. 12, Fig. 13 to Fig. Figure 14 shows that a magnetic ring 30 is inserted into the receiving pot, which is magnetized alternately as the north pole N and as the south pole S at equal intervals W in the circumferential direction.

[0071] In this way, twelve permanent magnets 31a are formed around the circumference. For the correct rotational position of the magnet ring 30 in the receiving cup of the rotor 52, detent grooves 39 are provided on the end faces. The position of the magnet ring 30 relative to the position of the crankshaft is determined by these detent grooves 39.

[0072] In its assembled state, the one-piece magnet ring 30 lies with its inner circumference at a slight distance above the outer circumference 21 of the stator 40; the stator 40 is completely enclosed within the magnet ring 30. When the rotor 52 rotates, the changing magnetization of the magnet ring 30 leads to an alternating flux in the poles 42a, thereby inducing an alternating voltage signal S, as described in Fig. 9 is shown.

Claims

[1] Internal combustion engine in a portable, hand-held power tool such as a chainsaw, cut-off saw, brush cutter, or blower, wherein the internal combustion engine (1) comprises a piston (6), a combustion chamber (5) with a spark plug (15), and a crankshaft (4) driven by the piston (6) and mounted in a crankcase (3) with an inlet (8) for combustion air and an outlet (9) for exhaust gases, a wheel body (50) rotating with the crankshaft (4), and an alternating current generator (16) driven by the crankshaft (4) which supplies an electrical load, wherein the alternating current generator (16) is arranged within the radial boundary of the wheel body (50) and outside the crankcase (3), wherein the stator (40) of the alternating current generator (16) is penetrated by the crankshaft (4), and the rotor (52) is non-rotatably connected to the wheel body (50).and wherein the rotor (52) is designed as a magnetic ring (30) covering the stator (40), characterized by , that the magnetic ring (30) is surrounded by a magnetic return ring (32). [2] Internal combustion engine according to claim 1, characterized by , that the wheel body (50) is formed by a part of a coupling connected to the crankshaft (4), through which a tool is driven. [3] Internal combustion engine according to claim 1, characterized by , that the wheel body (50) is formed by a blower wheel (51) which carries the rotor (52) on its end face facing the crankcase (3). [4] Internal combustion engine according to claim 1, characterized by , that the rotor (52) is integrated into the wheel body (50). [5] Internal combustion engine according to claim 1, characterized by , that the stator (40) lies within the outer contour of the wheel body (50), wherein the magnets (31) of the magnet ring (30) are held in receiving pockets (34, 53). [6] Internal combustion engine according to claim 5, characterized by that the receiving pockets (53) are formed in the wheel body (50). [7] Internal combustion engine according to claim 5, characterized by , that the receiving pockets (34) are formed in a retaining ring (33) which is inserted in a rotationally fixed manner into a receiving pot (55) of the wheel body (50). [8] Internal combustion engine in a portable, hand-held power tool such as a chainsaw, cut-off saw, brush cutter, blower, wherein the internal combustion engine (1) comprises a piston (6), a combustion chamber (5) with a spark plug (15) and a crankshaft (4) driven by the piston (6) and mounted in a crankcase (3), with an inlet (8) for combustion air and an outlet (9) for exhaust gases, with a wheel body (50) rotating with the crankshaft (4) and an alternating current generator (16) driven by the crankshaft (4) which supplies an electrical load, wherein the alternating current generator (16) is arranged within the radial boundary of the wheel body (50) and outside the crankcase (3), wherein the stator (40) of the alternating current generator (16) is penetrated by the crankshaft (4) and the rotor (52) is non-rotatably connected to the wheel body (50), characterized by, that the stator (40) is formed by a coil body (20) which is enclosed by a stator yoke with poles (42) located on the outer circumference (47). [9] Internal combustion engine according to claim 8, characterized by , that the stator yoke is composed of at least two sheets (41), in particular electrical steel sheets, wherein one sheet (41) is arranged on one end face of the coil support (20) and the other sheet (41) is arranged on the other end face of the coil support (20), that the poles (42) are located on the outer circumference (47) of the coil body (20) and that the sheets (41) interlock in a flux-conducting manner on the inner circumference (43), wherein the stator sheets (41) are preferably positively connected to each other or frictionally interlock on the inner circumference (43) of the coil body (20). [10] Internal combustion engine in a portable, hand-held power tool such as a chainsaw, cut-off saw, brush cutter, or blower, wherein the internal combustion engine (1) comprises a piston (6), a combustion chamber (5) with a spark plug (15), and a crankshaft (4) driven by the piston (6) and mounted in a crankcase (3) with an inlet (8) for combustion air and an outlet (9) for exhaust gases, a wheel body (50) rotating with the crankshaft (4), and an alternating current generator (16) driven by the crankshaft (4) which supplies an electrical load, wherein the alternating current generator (16) is arranged within the radial boundary of the wheel body (50) and outside the crankcase (3), wherein the stator (40) of the alternating current generator (16) is penetrated by the crankshaft (4), and the rotor (52) is non-rotatably connected to the wheel body (50). characterized by, that the distance between two adjacent poles (42) of the generator corresponds to the nth part of a crankshaft revolution, where n is an integer between 6 and 24. [11] Internal combustion engine according to claim 10, characterized by , that the stator (40) has twelve poles (42) distributed evenly around the circumference of a coil body (20). [12] Internal combustion engine according to claim 10, characterized by , that the rotational position of the stator (40) of the alternating current generator (16) on the crankcase (3) and the top dead center of the piston (6) are aligned with each other in such a way that a zero crossing (O i ) of the voltage signal (S) of the alternating current generator (16) is located at the top dead center of the piston (6). [13] Internal combustion engine in a portable, hand-held power tool such as a chainsaw, cut-off saw, brush cutter, blower, wherein the internal combustion engine (1) comprises a piston (6), a combustion chamber (5) with a spark plug (15) and a crankshaft (4) driven by the piston (6) and mounted in a crankcase (3), with an inlet (8) for combustion air and an outlet (9) for exhaust gases, with a wheel body (50) rotating with the crankshaft (4) and an alternating current generator (16) driven by the crankshaft (4) which supplies an electrical load, wherein the alternating current generator (16) is arranged within the radial boundary of the wheel body (50) and outside the crankcase (3), wherein the stator (40) of the alternating current generator (16) is penetrated by the crankshaft (4) and the rotor (52) is non-rotatably connected to the wheel body (50), characterized by, that the alternating current generator (16) is intended to serve as an ignition angle sensor and as an energy source. [14] Internal combustion engine according to claim 8, characterized by , that the coil body (20) has fastening means for fixing the stator (40) to the housing. [15] Internal combustion engine according to claim 14, characterized by , that the fastening means are designed as fastening tabs (46) formed on the coil body (20), which extend radially outwards from the coil body (20) beyond the outer circumference, wherein the fastening tab (46) preferably projects radially outwards through a recess (83) of a stator lamination (41). [16] Internal combustion engine according to claim 15, characterized by , that the fastening tab is formed in one piece with the coil body (20). [17] Internal combustion engine according to claim 14, characterized by, that the fastening means is designed as a circular wedge connection, wherein a circular wedge geometry is formed on the inner circumference (49) of the stator (40). [18] Internal combustion engine in a portable, hand-held power tool such as a chainsaw, cut-off saw, brush cutter, blower, wherein the internal combustion engine (1) comprises a piston (6), a combustion chamber (5) with a spark plug (15) and a crankshaft (4) driven by the piston (6) and mounted in a crankcase (3), with an inlet (8) for combustion air and an outlet (9) for exhaust gases, with a wheel body (50) rotating with the crankshaft (4) and an alternating current generator (16) driven by the crankshaft (4) which supplies an electrical load, wherein the alternating current generator (16) is arranged within the radial boundary of the wheel body (50) and outside the crankcase (3), wherein the stator (40) of the alternating current generator (16) is penetrated by the crankshaft (4) and the rotor (52) is non-rotatably connected to the wheel body (50), characterized by, that one end of a coil (22) of the stator (40) is connected to a stator lamination (41) and the other end of the coil (22) is connected to a signal line (17). [19] Internal combustion engine according to claim 18, characterized by , that an electrically conductive hollow rivet (81) is inserted in the coil body (20) of the coil (22), which is electrically connected to the other end (82) of the coil (22), and a connector (84) of the signal line (17) is inserted into the hollow rivet (81). [20] Internal combustion engine according to claim 18, characterized by , that an electrical connecting part (85) is held on the coil body (20) of the coil (20), which electrically connects one end (82) of the coil (22) and one end (17a) of the signal line (17), wherein the connecting part (85) is preferably a crimp connector (86). [21] Internal combustion engine according to claim 18, characterized by, that an electrical connecting part (85) is designed as a mandrel (87) held on the coil body (20), on which the end (82) of the coil (22) is wound, and the signal line (17) is provided with a socket (88) that can be plugged onto the mandrel (87), the inner contacts (89) of which make electrically conductive contact with the wound end (82) of the coil (22), wherein the socket (88) plugged onto the mandrel (87) is positively secured (41). [22] Internal combustion engine in a portable, hand-held power tool such as a chainsaw, cut-off saw, brush cutter, or blower, wherein the internal combustion engine (1) comprises a piston (6), a combustion chamber (5) with a spark plug (15), and a crankshaft (4) driven by the piston (6) and mounted in a crankcase (3) with an inlet (8) for combustion air and an outlet (9) for exhaust gases, a wheel body (50) rotating with the crankshaft (4), and an alternating current generator (16) driven by the crankshaft (4) which supplies an electrical load, wherein the alternating current generator (16) is arranged within the radial boundary of the wheel body (50) and outside the crankcase (3), wherein the stator (40) of the alternating current generator (16) is penetrated by the crankshaft (4), and the rotor (52) is non-rotatably connected to the wheel body (50). characterized by, that a stator lamination (41) of the stator (40) is composed of at least two partial laminations (41a, 41b, 41c), wherein the claws (42a, 42b, 42c) of the partial laminations (41a, 41b, 41c) are arranged one above the other or next to the other. [23] Internal combustion engine in a portable, hand-held power tool such as a chainsaw, cut-off saw, brush cutter, blower, wherein the internal combustion engine (1) comprises a piston (6), a combustion chamber (5) with a spark plug (15) and a crankshaft (4) driven by the piston (6) and mounted in a crankcase (3), with an inlet (8) for combustion air and an outlet (9) for exhaust gases, with a wheel body (50) rotating with the crankshaft (4) and an alternating current generator (16) driven by the crankshaft (4) which supplies an electrical load, wherein the alternating current generator (16) is arranged within the radial boundary of the wheel body (50) and outside the crankcase (3), wherein the stator (40) of the alternating current generator (16) is penetrated by the crankshaft (4) and the rotor (52) is non-rotatably connected to the wheel body (50), characterized by, that the claws (42) of the stator (40) have an asymmetrical geometry in top view, such that the direction of rotation can be detected on the basis of the alternating signal. [24] Internal combustion engine according to claim 1, characterized by , that the alternating current generator (16) is a claw pole generator. [25] Internal combustion engine according to claim 1, characterized by , that the alternating current generator (16) is a star generator. [26] Internal combustion engine in a portable, hand-held power tool such as a chainsaw, cut-off saw, brush cutter, blower, wherein the internal combustion engine (1) comprises a piston (6), a combustion chamber (5) with a spark plug (15) and a crankshaft (4) driven by the piston (6) and mounted in a crankcase (3), with an inlet (8) for combustion air and an outlet (9) for exhaust gases, with a wheel body (50) rotating with the crankshaft (4) and an alternating current generator (16) driven by the crankshaft (4) which supplies an electrical load, wherein the alternating current generator (16) is arranged within the radial boundary of the wheel body (50) and outside the crankcase (3), wherein the stator (40) of the alternating current generator (16) is penetrated by the crankshaft (4) and the rotor (52) is non-rotatably connected to the wheel body (50), characterized by, that the alternating current generator (16) is designed as a starter motor. [27] Internal combustion engine according to claim 25, characterized by , that the alternating current generator (16) is switched in a first operating mode as an energy source and / or as an ignition angle sensor and in a second operating mode as a starter motor for starting the internal combustion engine (1).

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