WO2006015393A2

WO2006015393A2 - Internal combustion engine

Info

Publication number: WO2006015393A2
Application number: PCT/AT2005/000272
Authority: WO
Inventors: Franz LAIMBÖCK
Original assignee: Avl List Gmbh
Priority date: 2004-08-09
Filing date: 2005-07-14
Publication date: 2006-02-16
Also published as: DE112005001774A5; WO2006015393A3

Abstract

The invention relates to the exhaust gas system (14) for an internal combustion engine (2), in particular to a manual handle device comprising an exhaust gas train (16) provided with at least one exhaust gas post-treating system (18) and comprising a first part (20) of the exhaust gas train upstream of the exhaust gas post-treating system (18) and a second part of the exhaust gas train downstream of the exhaust gas post-treating system (18). In order to obtain an as compact as possible mode by maximally using dynamic activities and minimising as much as possible the response behaviour of the exhaust gas post-treating system (18), the exhaust gas train (16) encircles at least partially said gas post-treating system (18).

Description

Internal combustion engine

The invention relates to an exhaust system for an internal combustion engine, in particular for a hand-held working device, with an exhaust gas treatment device having at least one exhaust gas upstream of the exhaust aftertreatment device and a zwe¬ th exhaust train part downstream of the exhaust aftertreatment auf¬ has. Furthermore, the invention relates to an internal combustion engine having a variable intake device, with a switching member for switching between at least two different intake lengths, with at least one first intake pipe per cylinder. Furthermore, the invention relates to an internal combustion engine for a Zweirad¬ vehicle, in particular for a moped or motorbike, with a kombinier¬ th engine and transmission housing for receiving at least one cylinder with a reciprocating piston, a crankshaft, at least one Aus¬ equal-wave and at least two, preferably three transmission shafts.

In order to enable a rapid start-up of an exhaust gas aftertreatment device formed, for example, by a catalytic converter, it is desirable to arrange it as close as possible to an internal combustion engine in the exhaust gas line. On the other hand, a sufficiently dimensioned resonance volume in the exhaust gas line between the internal combustion engine and the after-treatment device is advantageous for the use of the gas-dynamic activity in the exhaust gas line.

DE 42 03 507 A1 describes an exhaust system for two-stroke combustion engines with a catalyst arranged between the cylinder and the silencer. In order to increase the cylinder charge, an oscillating tube opens into the tube section between the cylinder and the catalytic converter, the length of which is dimensioned so that the reflection pressure wave returns to the cylinder at the time after the closing of the overflow channels and before the closing of the outlet window.

From DE 88 08 796 Ul an exhaust system with catalyst for two-stroke engines has become known, wherein the sufficient proximity of the catalyst to the exhaust flange on the cylinder, connected to a sufficiently large Reso¬ nanzraum, is solved in such a way that the catalyst is arranged within this space on a tubular extension, which is executed in this space to the Austrittsöff¬ tion of the cylinder and is thus swept by the still relatively warm exhaust gases of the cylinder. Similar conditions are described in EP O 401 196 A2, where the favorable distance of the catalyst to the cylinder with a small diameter Durchströmrohr is to be achieved.

The known exhaust systems have the disadvantage that they require a lot of space and thus are not suitable for installation in a hand-held implement.

Variable intake devices are used, for example, to switch between different resonance-effective intake pipe lengths in order to achieve a maximum gas-dynamic charging effect for each engine speed.

Each engine speed is associated with a certain intake length with a maximum gasdy¬ namischen charging effect. In order to achieve a high torque in the lower speed range without simultaneous loss of maximum power, the intake manifold must be changeable and adaptable to the respective speed. Known shift intake pipes realize this requirement by opening and closing additional channels by means of flat slide, rotary valve or Dros¬ selklappen.

From EP 0 201 180 Bl, for example, a shift intake manifold for a Brenn¬ engine is known, being switched over a switchover between a long and a short flow path. The disadvantage is that Schalt¬ suction of this type take a relatively large amount of space and are moderately expensive manufacture.

From the AT 3.397 Ul an internal combustion engine for a motorcycle is known in which assemblies of the internal combustion engine are designed in a modular manner and universally for at least two different cylinder arrangements. As a result, different performance classes and cylinder arrangements can be covered in a simple manner with low production and logistical effort. The Brenn¬ engine is suitable from conception only for motorcycles, not for other types of vehicles.

AT 6.292 U1 describes an internal combustion engine which has a main module including the engine housing, crank drive, change gear and transmission output line and at least one auxiliary module which can be attached to the main module, the change gear and transmission output line being mechanically separated within the main module and by mounting a first auxiliary Module on the main module are drehverbindbar. The combination of a main module for one cylinder and a main module for two cylinders with different sub-modules allows the largest possible number of sub-modules to be different vehicle requirements are covered. The modular construction of the concept makes it possible to realize diesel, gasoline, one-cylinder and two-cylinder engines with as many identical parts as possible and only two different engine housings. The engine is primarily suitable for so-called ATV (All Terrain Vehicles) vehicles, compact tractors, auto-rickshaws, micro-cars or the like. For two-wheeled vehicles, this concept is not suitable.

The object of the invention is to avoid these disadvantages and to provide an exhaust system with which on the one hand the gas-dynamic activity in the exhaust tract is utilized and on the other hand a rapid heating of the aftertreatment device is made possible. A further object of the invention is to develop a variable inlet device with which it is possible to switch over between a long and a short flow path in the smallest possible space and with minimal production outlay. It is also an object of the invention for two-wheeled vehicles, especially for mopeds or motorcycles to produce a gerin¬ gem production costs producible and suitable for many designs internal combustion engine.

According to the invention, this is achieved in that the exhaust gas line, preferably the first exhaust gas line section of the exhaust gas line, at least partially wraps around the exhaust gas aftertreatment system.

By looping around the exhaust aftertreatment system, the exhaust aftertreatment device is heated even before the exhaust gas enters the exhaust aftertreatment device. Thus, a quick response is possible. Despite the arrangement of the catalyst close to the engine, the first exhaust gas part between the cylinder outlet and the inlet into the exhaust after-treatment device forms a relatively large resonance volume due to the loop or loop-like arrangement and the comparatively large pipe length of the first exhaust line part, so that the exhaust system Swing tube exhaust can be designed.

In a particularly advantageous embodiment variant of the invention, it is provided that the part of the exhaust line that surrounds the exhaust aftertreatment system has at least four, preferably at least five, more preferably at least six deflection bends, wherein it is preferably provided that the deflection bends have deflection angles of about 90 ° / - 30 ° training.

At least two successive deflecting bends each span two differently oriented planes which enclose an angle of approximately 90 ° +/- 30 ° with each other. In a particularly simple design, it is provided that at least three successive deflections span three differently oriented planes which enclose angles of approximately 90 ° +/- 30 ° with each other.

A simple production is possible if the first exhaust line part consists at least partially of assembled half-shells.

Since the IMach treatment device is arranged in the center of the entangling part of the exhaust line, heat losses into the environment can be kept as low as possible.

In the context of the invention, it can further be provided that the exhaust gas after-treatment device and the part that surrounds it are arranged at least partially in a housing for the exhaust gas line. The housing has the function of a heat shield, it also being possible to reduce the surface temperature so that at least the part of the exhaust line enclosing the exhaust aftertreatment system is surrounded by cooling air and / or exhaust gas, preferably the cooling air and / or the exhaust gas flowing around the exhaust line through openings on one side of the housing.

Switching between a long and a short flow path in the smallest installation space and with minimal manufacturing effort can be achieved if the first intake pipe, which is preferably designed essentially as an intake funnel, is partially surrounded at its start region by a cup-like second intake pipe, wherein a first flow path defi The first intake opening can be closed by the switching element, and wherein a second flow path is preferably formed by an annular gap between the first and second intake pipes, wherein preferably the first intake opening is arranged in alignment with the first intake pipe in the second intake pipe.

It is provided that the second intake pipe is substantially pot-shaped, wherein the first intake opening is arranged in an end face of the pot.

A compact design can be achieved when the second intake pipe is slipped over the first intake pipe.

In a further embodiment it can be provided that a second intake opening defining the start of the second flow path is formed by the edge of the second intake pipe and the outer wall of the first intake pipe, preferably the inner wall of the second intake pipe and / or the outer wall of the first intake pipe preferably in the same Senses are conically inclined. The flow of the second flow path is directed counter to the intake flow. This can be achieved in a very small space a significant extension of Ansaugströmungsweges.

In a further embodiment of the invention it is provided that the switching elements of different first intake pipes, in particular of different cylinders are connected to each other.

The cross section of the first and / or second intake pipe may be oval, elliptical or rectangular with rounded corners. In this case, it is preferably provided that the cross section of the first and / or second flow path is designed to be tapered in the direction of flow, preferably continuously.

In a particularly advantageous embodiment of the invention, it is provided that the switching element has on its inside at least one preferably rotationally symmetrical flow guide surface. The flow guide surface is preferably designed to extend with the end face of the second intake pipe, in order to divert the flow of the second flow path as loss-free as possible into the first intake pipe.

In order to reduce the flow resistance of the intake flow, it can be provided that the surface of the first and / or second flow path has, at least in sections, a defined structure and / or a defined roughness depth. As a result, the boundary layer structure in the region of the surface of the flow paths can be effectively prevented.

In this case, provision may in particular be made for the surface to have a preferably golf ball-like structure with defined, preferably dent-shaped, recesses and / or preferably knob-like elevations, the structure having a depth or height of 0.1 mm to 0.4 mm , preferably 0.2 mm. It is very advantageous for the inhibition of the boundary layer structure, if the depressions or elevations are substantially circular and each have a diameter between 2 mm to 7 mm, preferably 3 mm to 6 mm, particularly preferably about 4 mm to 5 mm. In a particularly advantageous embodiment variant of the invention, it is provided that the recesses or elevations are arranged in two staggered rows, wherein the distance between two adjacent depressions or elevations is greater than their diameter and preferably between about 9 mm to 13 mm, particularly preferably 10 mm to 12 mm. Alternatively or additionally, it may be provided that the roughness depth is preferably between 10 μm and 20 μm. To enable simple production, it is provided that the internal combustion engine has a modular construction, and that at least one housing part of the engine transmission housing is designed for engine variants with different cylinders, boreholes, strokes and / or working methods vor¬ preferably at least three waves, preferably at least the crankshaft, a balancer shaft, a first gear shaft, a second gear shaft and a third gear shaft, in a parallel to the axis of the rear wheel arranged parting plane between an upper part and a lower part of the motor Getriebe¬ housing.

A modular design of the internal combustion engine is achieved when the upper part of the engine-transmission housing includes the cylinder block and the transmission superstructure, wherein the lower part of the engine-transmission housing includes the transmission substructure.

It is particularly advantageous if the lower part of the engine transmission housing can be used for at least two engine variants with different cylinders, cylinder bores, strokes or working methods.

It is preferably provided that the dividing plane has an angle between -45 ° and + 45 ° to a reference plane parallel to the contact surface and containing the axis of the rear wheel. The internal combustion engine can be used particularly advantageous in motorcycles when the cylinder is arranged away from the transmission superstructure, wherein the cylinder axis with the parting plane preferably includes an angle greater than 120 °, preferably between 120 ° and 150 °. Depending on the inclination of the parting plane relative to the reference plane, the cylinder head may be arranged in or below the passage of the motor bicycle.

A particularly simple production is possible if the bearings of at least one shaft are formed as half-shells, wherein a first half-shell is arranged in each case in the lower part and the second half-shell in the upper part of the motor-gear housing. By combining two bores and two strokes, four motor sizes can be realized with the modular system according to the invention. The lower part of the motor-gear housing is in each case the same, wherein the power between the minimum and the maximum variant can be doubled.

In the two-stroke variant, one or two cylinder heads for one to two cylinders can optionally be used with a lower part of the engine transmission housing. The gearbox is identical for both versions.

In the four-stroke version, a cylinder for short as well as for long stroke ein¬ settable. The upper part of the engine-transmission housing, which cylinder block and Transmission superstructure is, like the lower part of the motor-gear housing for both variants used.

The internal combustion engine may be formed by air-cooled, fan-cooled or wasserge¬ cooled.

The invention will be explained in more detail below with reference to FIGS. Show it:

1 shows an internal combustion engine with an exhaust system according to the invention in a longitudinal section through a cylinder;

2 shows the exhaust system in a view according to the arrow II in Fig. 3 and Fig. 5;

3 is a view of the exhaust system according to the arrow III in Fig. 2 and Fig. 4;

4 is a view of the exhaust system according to the arrow IV in Fig. 3 and Fig. 5;

5 is a view of the exhaust system according to the arrow V in Fig. 4 and Fig. 2.

Fig. 6 is an oblique view of the exhaust system;

7 shows a further oblique view of the exhaust system;

8 shows a variable intake device according to the invention in a first embodiment in a longitudinal section in a first operating position;

9 shows this variable intake device in longitudinal section in a second operating position;

10 shows a variable inlet device in a second embodiment in longitudinal section in a first operating position;

11 shows this variable intake device in longitudinal section in a second operating position;

Fig. 12 is a detail of the surface of the flow paths;

FIG. 13 shows the surface in a section according to line XIII-XIII in FIG. 12; FIG.

14 shows a two-wheeled vehicle with built-in internal combustion engine according to the invention; 15 shows the internal combustion engine according to the invention in an embodiment variant; and

16 shows the internal combustion engine according to the invention in a second embodiment variant.

1 shows a slot-controlled two-stroke internal combustion engine 2 with a piston 6 which reciprocates in a cylinder 4 and which opens an inlet opening 8 and an outlet opening 10.

To the outlet channel 12, an exhaust system 14 is connected, which has an exhaust line 16 with an exhaust gas aftertreatment device 18. The exhaust aftertreatment device 18 may for example consist of a catalyst. The exhaust gas line has a first exhaust gas line part 20 between outlet channel 12 and exhaust gas aftertreatment device 18 and a second exhaust gas line part downstream of the exhaust gas aftertreatment device 18, which can be connected to a flange 22 of the exhaust gas aftertreatment device 18. The first exhaust-gas tract part 20 is designed such that the exhaust-gas aftertreatment device 18 is at least partially surrounded by it, so that the exhaust-gas aftertreatment device 18 is arranged approximately in the center of the wrap-around part of the exhaust line 14. On the one hand, the exhaust-gas aftertreatment device 18 is heated very quickly to operating temperature by the entraining first exhaust-gas tract part 20 after the starting process of the internal combustion engine 2. On the other hand, due to the relatively long tube length, the first exhaust-gas system part 20 forms a resonant resonating chamber which is available for utilizing the gas-dynamic activity of the internal combustion engine 2.

In this case, the first exhaust-gas tract part 20 has successive deflecting curves 24, 26, 28, 30, 32, 34, 36 and 38, the starting-pipe section 24 being flanged to the outlet channel 12. The tail pipe section 38 opens into the exhaust after-treatment device 18. The entry into the exhaust system 14 is indicated by the arrow I, the exit of the exhaust aftertreatment system 18 by the arrow O. The outlet opening from the exhaust gas aftertreatment device 18 is further provided with reference numeral 40. The inlet opening in the first exhaust-gas system part 20 bears the reference numeral 42.

The Umlenkbögen 28 to 36 each have deflection angle δ of about 90 ° +/- 30 °. At least two successive deflecting bends 28, 30; 30, 32; 32, 34; in each case clamp two differently oriented planes εi, ε ₂ , ε ₃ , ε ₄ , which mit¬ angle angle α _lr α ₂ , 013 of about 90 ° +/- 30 °. At least three successive deflecting curves 28, 30, 32; 30, 32, 34 each have three differently oriented planes ε _lr ε ₂ , ε ₃ , ε ₄ , which enclose the angle of about 90 ° +/- 30 ° with each other.

Two Umlenkbögen 34 stretch at least approximately the same level ε ₄ .

As can be seen in particular from Fig. 1, the Umlenkbögen 26 to 36 each consist of assembled, for example, soldered, welded or glued shells. This allows for easy production.

The exhaust aftertreatment device 18 and the part of the exhaust line 16 that surrounds it are at least partially arranged in a housing 40, which has the function of a heat shield. To reduce the surface temperature of the housing 40, the exhaust gas line 16 is surrounded by cooling air and / or exhaust gas. The cooling air exits through openings 41 on a front side of the housing 40 again.

The exhaust system described requires only little space, making it particularly suitable for internal combustion engines of hand-held implements, such as chainsaws.

The variable intake device 102 includes a first intake pipe 104 and a second intake pipe 106. The second intake pipe 106 is concentrically slipped over the first intake pipe 104 and has a substantially cup-shaped shape.

The first intake pipe 104 is essentially formed by an intake funnel which tapers in the direction of flow S and is fastened via a flange 105 to the cylinder head 108 of an internal combustion engine (not shown). 110 is an inlet channel leading to a combustion chamber of a cylinder. Air intake funnels of this type are frequently used in racing engines.

The second intake pipe 106 has an end face 112 with an inlet 116 which can be closed by a switching element 114, which defines a first flow path Si.

The second intake pipe 106 is spaced from the first intake pipe 104, so that between the first and the second intake pipe 104, 106 an annular channel 118 defining the second flow path S ₂ is formed. The edge 120 of the second intake pipe and an outer wall 122 of the double-walled first intake pipe 104 define an annular inlet opening 124 in the annular channel 118. For fastening the second intake pipe 106 and for keeping a predefined distance between the two intake pipes 104, 106 are webs 119, for example, on the first intake pipe 104, is provided. First and / or second intake pipes 104, 106 may have a circular, oval, elliptical or rectangular cross-section with rounded corners.

Depending on the engine operating state-for example, as a function of the rotational speed-the air can either flow over a short intake path, namely the first flow path Si or via a long intake path, namely the second flow path S, through the switching element 114 of the variable intake device 102 _{2 are} sucked. The short first flow path S ₁ is used at higher speeds, the long second flow path S ₂ at low speeds of rotation of the motor.

FIGS. 8 and 10 show the position of the switching element 114 at high speeds. Through the open switching element 114, which is designed as a flap, for example, air can flow through the first inlet opening 116 and be supplied directly to the inlet channel 110 of the internal combustion engine within the first inlet tube 104.

9 and 11 show the inlet device 102 with the switching element 114 closed. In this case, the intake air flows through the second inlet opening 124 into the annular channel 118 and is deflected in the area of the end face 112 into the interior of the first intake tube 104. Since the intake air is supplied to the inlet channel 110 via the second longer flow path S ₂ , maximum gas-dynamic charging effects can be achieved even in the lower rpm range.

In the embodiment variant shown in FIG. 11, the switching element 114 has on its inner side 115 a rotationally symmetrical toroidal flow guide surface 126, which diverts the flow from the annular channel 118 into the first intake pipe 104. In this case, the flow guide surface 126 is designed to extend with the end face 112 of the second intake pipe 106 in order to minimize the flow losses. At least approximately a profile of the flow paths Si, S ₂ tapering continuously in the direction of flow can be realized by the flow guide surface 126.

The first and second intake pipe 104, 106 can be made particularly simple as a plastic injection molded part.

The surface of the flow paths S _x , S ₂ may have, at least in sections, a precisely defined structure 130, for example a golf ball-like structure with recesses 131 or elevations, as shown in FIGS. 12 and 13. The dome-like recesses 131, for example, have a depth t of approximately 0.1 mm to 0.4 mm in the exemplary embodiment and a circular shape. diameter d between 3 mm to 6 mm. The distance a between two recesses 131 is greater than the diameter d and is for example about 10 mm to 12 mm. The recesses 131 are arranged in staggered rows.

Alternatively or additionally, the surface of the flow paths Si, S _{2 may have} a defined roughness depth r _t of, for example, 10 μm to 20 μm.

Thus, a boundary layer structure of the flow can be prevented and flow losses can be reduced.

FIG. 15 shows an internal combustion engine designed as a four-stroke engine.

The internal combustion engine 202 for a two-wheeled vehicle 201, for example a moped or a motorbike, has at least one cylinder 204 with a reciprocating piston 206, which acts on a crankshaft 210 via a connecting rod 208. The cylinder 204 is disposed in an engine transmission housing 212 which performs the function of a cylinder block, crankcase and transmission housing. The engine transmission housing 212 consists of a top 214 with the cylinder block 216 and transmission superstructure 218 of the transmission 234, and a bottom 220 forming the transmission base 219. The top 214 and bottom 220 of the engine transmission housing 212 include the balancer shaft 222, the crankshaft 210 and the transmission shafts 224, 226, 228, which are arranged in the division plane 230 of the upper part 214 and the lower part 20.

With the cylinder block 216 of the upper part 214, a cylinder head 232 is firmly ver¬ connected.

The cylinder block 216 of the upper part 214 of the engine gear housing 202 is arranged so that the cylinder 204 faces away from the gear 234. The Zylin¬ derachse 235 has the dividing plane 230 - measured in the direction of the gear 234 - an angle α greater than 120 °. The angle between the division plane 230 and a reference plane 238 parallel to the contact surface 236 of the two-wheeled vehicle 201 through the axis 240 of the rear wheel 242 is approximately 20 ° in the embodiment shown in FIGS. 14 and 15. This permits free passage in the two-wheeler vehicle 201. In a so-called "step-over" application, however, the angle β can also be 0 or less than 0.

According to the described modular system, in the four-stroke engine, at least one long-stroke and at least one short-stroke variant can be produced by a single cylinder 204 and a single upper part 214 of the engine transmission housing 212 be realized, wherein the cylinder 204 is shortened ge according to the requirements.

In the two-stroke engine, by using two cylinder heads 232 and two cylinders 204 and a single lower part 220 of the engine transmission housing 212, different engine variants can be realized.

The internal combustion engine 202 shown in FIG. 16 differs from FIG. 15 primarily in that it is designed as a two-stroke engine. Cylinder block 216, crankcase and upper gear housing are also formed here by an upper part 214 of a common motor-gear housing 212. The division plane 230 between the upper part 214 and the lower part 220 of the motor gear housing 212 also includes the balancer shaft 222, the crankshaft 210 and the gear shafts 224, 226 and 228. For the angles α, β, the same applies as for the four-stroke engine ,

The modular engine 202 has a common lower part 220 for several embodiments of the internal combustion engine 202. By combining with different upper parts 214 of the motor-gear housing 212, for example with two different bores and two strokes, a plurality of motor sizes, in the concrete example four motor sizes, can be used. By using different upper parts 214, the power between a minimum variant and a maximum variant can be considerably increased, for example doubled. The graduation plane 230 is aligned at least approximately hori zontal. The shafts 222, 210, 224, 226, 228 are mounted in half shells which are not shown further, wherein in each case a first half shell in the upper part 214 and a second half shell in the lower part 220 are arranged per bearing. This design makes a very simple installation possible.

The internal combustion engine 202 may be configured wind-cooled, fan-cooled or water-cooled.

Claims

PATENT APPLICATIONS

1. Exhaust system (14) for an internal combustion engine (2), in particular for a hand-held implement, with an at least one exhaust aftertreatment device (18) having exhaust line (16) having a first Ab¬ gas string part (20) upstream of the exhaust aftertreatment device (18) and a second exhaust tract part downstream of the Abgasnachbe¬ treatment device (18), characterized in that the exhaust line (16) at least partially wraps around the exhaust aftertreatment system (18).

2. Exhaust system (14) according to claim 1, characterized in that the first exhaust gas system part (20) at least partially wraps around the exhaust aftertreatment system (18).

3. Exhaust system (14) according to claim 1 or 2, characterized in that the exhaust aftertreatment system (18) looping around Ab¬ gasstranges (16) at least four, preferably at least five, more preferably at least six Umlenkbögen (26, 28, 30, 32, 34, 36) auf¬.

4. Exhaust system (14) according to claim 3, characterized in that zu¬ at least one deflecting bend (26, 28, 30, 32, 34, 36) forms a deflection angle (δ) of about 90 ° +/- 30 °.

5. Exhaust system (14) according to claim 3 or 4, characterized in that at least two successive Umlenkbögen (28, 30, 30, 32, 32, 34) in each case two differently oriented planes (εi, ε ₂ , ε ₃ , ε ₄ ), which enclose angles (αi, α ₂ , α ₃ ) of approximately 90 ° +/- 30 ° with each other.

6. Exhaust system (14) according to one of claims 3 to 5, characterized gekenn¬ characterized in that at least three successive Umlenkbögen (28, 30, 32, 30, 32, 34) three differently oriented planes (εi, ε ₂ , ε ₃ ; ε ₂ , ε ₃ , ε ₄ ), which angles {a _lf α ₂ ; α ₂ , α ₃ ) of about 90 ° +/- 30 °.

7. Exhaust system (14) according to any one of claims 3 to 6, characterized gekenn¬ characterized in that at least two successive Umlenkbögen (34, 36) in the same plane (ε ₄ ) are arranged.

8. Exhaust system (14) according to any one of claims 1 to 7, characterized gekenn¬ characterized in that the aftertreatment device (18) in the center of the um¬ looping part of the exhaust line (16) is arranged.

9. Exhaust system (14) according to any one of claims 1 to 8, characterized gekenn¬ characterized in that the exhaust system (14) is designed as a vibration tube exhaust.

10. Exhaust system (14) according to any one of claims 1 to 9, characterized gekenn¬ characterized in that the first exhaust line part (20) consists at least partially zu¬ sammengefügten half shells.

11. Exhaust system (14) according to claim 10, characterized in that the exhaust gas aftertreatment device (18) and the part wrapped around the exhaust line (16) at least partially in a housing (40) is arranged ange¬.

12. Exhaust system (14) according to claim 10 or 11, characterized in that at least the exhaust aftertreatment device (18) umschlin¬ ing part of the exhaust line (16) is surrounded by cooling air and / or exhaust gas, wherein preferably the cooling air and / or the Exhaust line (16) flowing exhaust gas through openings (41) on one side of the housing (40) emerges.

13. Internal combustion engine having a variable intake device (102), with a switching member (114) for switching between at least two different intake lengths, with at least one first intake pipe (104) per cylinder, characterized in that the first substantially as Ans¬ suction funnel formed first Intake pipe (104) at its beginning region of a pot-like second intake pipe (106) is partially surrounded um¬ partially, wherein a first flow path (Si) defining first intake port (116) by the switching member (114) is closable, and wherein a second Flow path (S ₂ ) preferably by an annular gap (118) between the first and the second intake pipe (104, 106) gebil¬ det is.

14. Internal combustion engine according to claim 13, characterized in that the first intake opening (116) is arranged in alignment with the first intake pipe (104) in the second intake pipe (106).

15. Internal combustion engine according to claim 13 or 14, characterized in that the second intake pipe (106) is substantially pot-shaped, wherein the first suction port (116) is disposed in an end face (112) of the pot.

16. Internal combustion engine according to any one of claims 13 to 15, characterized ge indicates that the second intake pipe (106) via the first intake pipe (104) is slipped over.

17. Internal combustion engine according to one of claims 13 to 16, characterized ge indicates that the beginning of the second flow path (S ₂ ) defining the second suction port (124) through the edge (120) of the second intake pipe (106) and the outer wall (122 ) of the first intake pipe (104) is formed.

18. Internal combustion engine according to any one of claims 13 to 17, characterized ge indicates that the inner wall of the second intake pipe (106) and / or the outer wall (122) of the first intake pipe (104), preferably in the same direction, are conically inclined.

19. Internal combustion engine according to any one of claims 13 to 18, characterized ge indicates that the second flow path (S ₂ ) in the annular gap (118) is directed substantially opposite to the intake flow (S) in the first An¬ suction tube (104).

20. Internal combustion engine according to any one of claims 13 to 19, characterized ge indicates that the switching elements (114) of different first An¬ suction tubes (104), in particular of different cylinders are interconnected.

21. Internal combustion engine according to any one of claims 13 to 20, characterized ge indicates that the second intake pipe (106) is arranged concentrically to the first intake pipe (104).

22. Internal combustion engine according to any one of claims 13 to 21, characterized ge indicates that the cross section of the first intake pipe (104) and / or the second intake pipe (104, 106) is substantially oval, elliptical or rectangular, preferably with rounded corners ,

23. Internal combustion engine according to any one of claims 13 to 22, characterized ge indicates that the cross section of the first and / or second Strö¬ mungsweges (Si, S ₂ ) is formed in the flow direction, preferably continuously, ver¬ younger.

24. Internal combustion engine according to one of claims 13 to 23, characterized ge indicates that switching member (114) on its inside (115) at least at least one preferably rotationally symmetrical flow guide surface (126).

25. Internal combustion engine according to any one of claims 13 to 24, characterized ge indicates that the and / or second intake pipe (104, 106) is formed as Kunst¬ injection molded part.

26. Internal combustion engine according to one of claims 13 to 25, characterized ge indicates that the surface of the first and / or second Strö¬ mungsweges, at least in sections, a defined structure (130) and / or a defined roughness depth.

27. Internal combustion engine according to claim 26, characterized in that the surface has a preferably golf ball-like structure (130) with definier¬ th, preferably dellenförmigen, recesses (131) and / or preferably wise knob-like elevations.

28. Internal combustion engine according to claim 26 or 27, characterized in that the structure has a depth (t) or height of 0.1 mm to 0.4 mm, preferably about 0.2 mm.

29. Internal combustion engine according to claim 27 or 28, characterized in that the recesses (131) or elevations are substantially circular and each have a diameter (d) between 2 mm to 7 mm, preferably 3 mm to 6 mm, particularly preferably about 4 mm to 5 mm.

30. Internal combustion engine according to any one of claims 27 to 29, characterized ge indicates that the recesses (131) or elevations are arranged in two ver¬ translated rows, wherein the distance (a) between two be¬ adjacent recesses (131) or Raisings is greater than the Durch¬ diameter (d) and preferably between about 9 mm to 13 mm, particularly preferably 10 mm to 12 mm.

31. Internal combustion engine according to any one of claims 26 to 30, characterized ge indicates that the roughness (r _t ) is preferably between 10 .mu.m to 20 .mu.m.

32. Internal combustion engine (202) for a two-wheeled vehicle (201), in particular for a moped or motor cycle, with a combined motor and Getriebe¬ housing (212) for receiving at least one cylinder (204) with a reciprocating piston (206) , a crankshaft (210), at least ei¬ ner balancing shaft (222) and at least two, preferably three gearbox Shafts (224, 226, 228), characterized in that the Brennkraft¬ machine (202) has a modular construction, and that at least one housing part of the motor-gear housing (212) for engine variants with different cylinders, bores, strokes and / or working methods is trained.

33. Internal combustion engine (202) according to claim 32, characterized in that at least three shafts, preferably at least the crankshaft (210), a balance shaft (222), a first transmission shaft (224), a second Ge transmission shaft (226) and a third Transmission shaft (228), in a parallel to the axis (240) of the rear wheel (242) arranged dividing plane (230) between an upper part (218) and a lower part (220) of the Motor-Getriebe¬ housing (212) lie.

34. Internal combustion engine (202) according to claim 33, characterized in that the upper part (218) of the engine transmission housing (212) cylinder block (216) and transmission superstructure (218) is formed.

35. Internal combustion engine (202) according to claim 33 or 34, characterized gekenn¬ characterized in that the lower part (220) of the motor-gear housing (212) forms the transmission base (219).

36. Internal combustion engine (202) according to any one of claims 32 to 35, characterized in that the dividing plane (230) to a surface Aufstandsflä¬ (236) of the two-wheeled vehicle (201) parallel, the axis (240) of the rear wheel (242) containing Reference plane (238) has an angle (ß) between -45 ° and + 45 °.

37. Internal combustion engine (202) according to any one of claims 32 to 36, characterized in that the cylinder (204) from the transmission superstructure (218) ab¬ turned, wherein the cylinder axis (235) with the Teilungs¬ plane (230) preferably a Angle (α) greater than 120 °, preferably between 120 ° and 150 °, includes.

38. Internal combustion engine (202) according to any one of claims 32 to 37, characterized in that the lower part (220) of the motor-gear housing (212) for at least two engine variants with different cylinders, cylinder bores, strokes or working methods can be used.

39. Internal combustion engine (202) according to any one of claims 32 to 38, characterized in that the bearings of at least one shaft (222, 210, 224, 226, 228) are formed as half shells, wherein a first half shell each because in the lower part (220) and a second half-shell in the upper part (218) is arranged ange¬.

40. Internal combustion engine (202) according to any one of claims 32 to 39, characterized in that the internal combustion engine (202) is formed wind-cooled, ge blown or water-cooled.