EP3387234A1

EP3387234A1 - Internal combustion engine

Info

Publication number: EP3387234A1
Application number: EP16809371.4A
Authority: EP
Inventors: Volker Cornelius; Michael Reinhardt
Original assignee: Volkswagen AG
Current assignee: Volkswagen AG
Priority date: 2015-12-10
Filing date: 2016-12-08
Publication date: 2018-10-17
Anticipated expiration: 2036-12-08
Also published as: DE102015224909A1; CN108368775B; EP3387234B1; CN108368775A; WO2017097934A1

Abstract

The invention relates to an internal combustion engine comprising a cylinder (12), a piston (18) that is movably located within the cylinder (12), a crankshaft (14) and a connecting rod (22) that connects the piston (18) to a crank pin (30) of the crankshaft (14). Rotatably mounted within the connecting rod top end (26) of the connecting rod (22) is an eccentric sleeve (40), which rotatably holds the crank pin (30) and which can be locked in relation to the connecting rod (22) in at least two rotational orientations by means of a locking device (52). The internal combustion engine is provided with at least one coupling device (100), by means of which the eccentric sleeve (40) can be temporarily coupled to the crankshaft (14), in order to rotate the eccentric sleeve (40) in relation to the connecting rod (22). This allows a rotation of the crankshaft (14) and the crank pin (30) relative to the connecting rod (22) to be utilized during operation of the internal combustion engine, in order to temporarily entrain the eccentric sleeve (40), thereby rotating said sleeve rapidly and securely from one rotational direction into the other.

Description

description

Internal combustion engine

The invention relates to an internal combustion engine with a cylinder, one within the

Cylinder movably guided piston, a crankshaft and connecting the piston to a crank pin of the crankshaft connecting rod, wherein within a connecting rod of the connecting rod a crank pin rotatably receiving eccentric sleeve is rotatably mounted, which is lockable in at least two Drehausrichtungen with respect to the connecting rod by means of a locking device.

Such an internal combustion engine allows operation with a variable

Compression ratio, which sets as a result of a function of the Dre92 alignment of the eccentric sleeve resulting variable distance between the crank pin and the piston. By adapting the compression ratio to different operating states of the internal combustion engine, its thermodynamic function can be improved and thus, in particular, the efficiency of the energy utilization and / or the power output in different load ranges can be improved.

A generic internal combustion engine is known for example from DE 197 03 948 C1. It also discloses that a rotation of the eccentric sleeve between the two provided Drehausrichtungen normally takes place completely automatically by acting on the eccentric sleeve as a result of the rotation of the crankshaft and the associated Pleuelbewegung forces. In addition, it could be provided to integrate into the connecting rod a hydraulic motor, by which a rotation of the eccentric sleeve could be effected in a non-locked by the locking device state.

In practice, it has been shown that a rotation of the eccentric sleeve in a

generic internal combustion engine, which is based solely on the from the operation of the

Internal combustion engine should be based on the eccentric sleeve acting forces, not reliable or at least not fast enough works. The further proposed in DE 197 03 948 C1 integration of a hydraulic motor for active rotation of the eccentric sleeve is on the one hand structurally very expensive and on the other hand increases the mass of the connecting rod to a considerable extent, which in particular due to the translational reciprocating motion of the connecting rod the occurring large accelerations is problematic. A generic internal combustion engine is furthermore known from EP 0 438 121 B1. However, this does not address how it should come to a rotation of the local eccentric sleeve between the two intended Drehausrichtungen.

Based on this prior art, the present invention seeks to provide a way to ensure a safe and / or fast rotation of the eccentric sleeve between the at least two Drehausrichtungen in a generic internal combustion engine.

This object is achieved by means of an internal combustion engine according to the patent claim 1. Advantageous embodiments of the internal combustion engine according to the invention are objects of the other claims and will become apparent from the following description of the invention.

To solve the problem is in an internal combustion engine comprising at least one cylinder, a piston movably guided within the cylinder, a crankshaft and connecting the piston with a crank pin of the crankshaft connecting rod, within a connecting rod of the connecting rod a crank pin rotatably receiving eccentric sleeve in turn rotatably mounted, which is in some cases lockable in at least two Drehausrichtungen with respect to the connecting rod by means of a locking device, according to the invention provided a coupling device by means of the eccentric sleeve is temporarily coupled to the crankshaft and in particular to one or both cheeks of the crank pin to the eccentric sleeve relative to the Twist connecting rod.

According to the invention, therefore, a rotation of the crankshaft or the

Used crankpin relative to the connecting rod in the operation of the internal combustion engine to take the eccentric sleeve temporarily and thereby rotate quickly and safely from one to the other Drehausrichtung. This is preferably always done when the eccentric sleeve is not locked in one of the Drehausrichtungen by means of the locking device. Since a crankshaft of an internal combustion engine normally always rotates in one direction of rotation, rotation of the eccentric sleeve thus always takes place in a (same) direction of rotation relative to the connecting rod.

In a preferred embodiment of the internal combustion engine according to the invention can be provided that the coupling device (particularly preferably exclusively) positively acting. This can in particular simplify the structural design of the coupling device and a sudden entrainment of the eccentric sleeve by the crankshaft, as in a likewise conceivable positively acting

Coupling device could be the case can be avoided. This aspect may be particularly relevant because in an operation of a generic

Internal combustion engines large difference angular velocities between the rotationally fixed in one of the Drehausrichtungen relative to the connecting rod arranged eccentric sleeve and the crankshaft or the or the cheeks of the associated crankshaft journal of the crankshaft can be present.

Such a non-positively acting coupling device can in a preferred

Embodiment of the internal combustion engine according to the invention preferably be designed such that the crankshaft and the eccentric sleeve each having a coupling surface which form a coupling gap with in a radial direction (ie radially inwardly or radially outwardly with respect to the axis of rotation of the eccentric sleeve within the connecting rod eye) decreasing gap width, wherein a coupling element can be brought into a first position and a second position, which in terms of the radial position within the coupling gap and thus with respect to the contact pressure between the coupling element and the

Different coupling surfaces of the eccentric sleeve and the crankshaft. Such

Coupling device is thus operated radially, but acts primarily in the axial direction, i. the normally directed pressure forces, which cause a frictional connection in the contacting coupling surfaces, are aligned at least more in the axial direction with respect to the axis of rotation of the eccentric sleeve within the connecting rod than radially thereto.

Preferably, it can be provided that the first position of the coupling element by a relatively large contact pressure and the second position by a relatively small

Contact pressure is marked. Further preferably, it can be provided that the contact pressure in one (in particular the first) of the positions of the coupling element is so great that sets a substantially slip-free entrainment of the eccentric sleeve by the crankshaft. Also preferably, it can be provided that the contact pressure in the other (in particular the second) of the positions of the coupling element is as low as possible and in particular essentially zero, so that in an advantageous manner friction losses due to a contacting relative movement between the coupling surfaces on the one hand and the coupling element on the other hand so far be avoided as possible when the

Locking device in one of the Drehausrichtungen with respect to the connecting rod by means of Locking device is locked and consequently the internal combustion engine is operated with temporarily unchanged compression ratio.

In a further preferred embodiment it can be provided that the non-positively acting coupling device is self-reinforcing, so that frictional forces acting between the coupling surfaces of the crankshaft and the eccentric sleeve on the one hand and the coupling element on the other hand due to an initial load, from further geometric reasons, a further retraction of the coupling element effect in the narrowing coupling gap, which is accompanied by a corresponding increase in contact pressure. By means of such a coupling device relatively high and in particular up to a slip-free coupling self-reinforcing frictional forces can be generated with a relatively low output load. The output load for the coupling element of such a coupling device may result in particular from an elastic loading of the coupling element. Alternatively or additionally, this may also arise as a result of inertial forces (in particular gravitational and / or centrifugal forces). It can also be provided to actively apply this output load by means of an actuator.

Preferably, it may be provided that the coupling surface (s) of the crankshaft and / or the eccentric sleeve (and preferably also one or more coupling surfaces of the

Coupling element) at an angle with respect to that plane which is aligned radially to the axis of rotation of the eccentric sleeve within the connecting rod, are aligned, which is <5 °, and preferably about 3 °. Smaller angles can in certain embodiments of the coupling device such a large self-locking effect for due to the

Frictional forces further in the coupling gap drawn coupling element cause thereby a reliable release of the coupling device is considerably more difficult. On the other hand, if the angle is too large, relatively large radially directed forces may be required in order to achieve the required contact pressure between the coupling surfaces of the eccentric sleeve and the crankshaft and of the coupling element.

In a preferred embodiment of the internal combustion engine according to the invention can also be provided that the coupling element is resiliently acted upon. This is to be understood that the coupling element by means of a prestressable spring element, which may also be the coupling element itself, is acted upon in the direction of movement of the coupling element in one of the positions. Such elastic

Actuation can ensure that the coupling element automatically into a Starting position moves, as long as this is not affected by a measure otherwise.

In a further preferred embodiment of such inventive

Internal combustion engine can then be provided that the coupling element occupies the first position in the elastic non-applied state or as a result of a constructive elastic loading, while the second position by means of an activatable

Adjustment device is adjustable. In this case, the first position may be in particular that in which the contact pressure between the coupling surfaces of the eccentric sleeve and the crankshaft on the one hand and the coupling element on the other hand is higher than that in the second position. As a "constructive elastic loading" is a bias of the

Coupling element acted upon spring element (or the self-elastically deflected coupling element) understood that without active influence of the

Spring element due to a constructive integration in the coupling device by a support of two sections, in particular end portions of the spring element adjusts to elements of the coupling device.

Preferably, it can be provided that the adjusting device is an adjustable

Having stop element for the coupling element. This may further preferably be designed such that the stop element can be activated and deactivated, wherein it forms a stop for the coupling element in the activated state and in the deactivated state does not form a stop for the coupling element. For this purpose, it can be particularly preferably provided that when the stop element is deactivated, the coupling element is moved so far into the coupling gap as a result of an elastically non-applied state or a constructive elastic loading that (possibly in conjunction with a self-reinforcing effect of the coupling device) the eccentric sleeve of the Crankshaft entrained and thus rotated relative to the connecting rod, while an activated stop element on this as a result of the rotation of the eccentric sleeve incident portion of the coupling element causes this is so far out of the narrowing coupling gap that no entrainment of the

Eccentric sleeve by the crankshaft more and in particular substantially no relevant friction between the coupling surfaces of the eccentric sleeve and the

Crankshaft on the one hand and the coupling element on the other hand is given more.

In a preferred embodiment of the internal combustion engine according to the invention can be provided that the coupling element forms coupling surfaces, which to the Coupling surfaces of the crankshaft and the eccentric sleeve (respectively) are aligned in parallel. As a result, an advantageous frictional effect between each

co-operating clutch surfaces can be achieved.

Further preferably, it may be provided that a (preferably positively acting) locking element of the locking device also serves as a stop element of the coupling device. This can be useful in particular if the stop element is to be used to release the coupling device (i.e., to reduce or eliminate the non-positive effect), since in the case of the internal combustion engine according to the invention this is simultaneously blocked by blocking of the eccentric sleeve in one of the locking devices

Drehausrichtungen should be made with respect to the connecting rod. Accordingly, a structurally advantageous dual function can be realized for the blocking element.

Furthermore, it can be provided for the internal combustion engine according to the invention that a / the (preferably slidably mounted on the connecting rod) blocking element of the locking device in a locking recess of the connecting rod or (preferably) of the eccentric sleeve is movable, wherein the locking recess with respect to an orbit of the locking element, on this relative to the blocking recess forming component in a relative rotation between the

Eccentric sleeve and the connecting rod revolves, a (preferably at least 50%, more preferably at least 100%) larger dimension than that for intervention in the

Has blocking recess provided part of the blocking element. The term "blocking depression" is intended to also encompass passage openings into which the blocking element or at least a part thereof can engage to form a form-locking barrier ensure the blocking element and the blocking recess forming component.

To a mobility between the blocking element or the component carrying the locking element (in particular the connecting rod) and the component forming the locking recess (in particular the eccentric sleeve) in engaging in the locking recess

Preferably, to avoid or limit the blocking element despite such a relatively large locking recess, preferably a return blocking element may further be provided, which can engage with the blocking element in the locking recess and thereby a portion of the locking recess, in which the locking element after the intervention in the

Barrier recess is not arranged, can fill out. It can also be provided that the blocking element and the backstop element, if both these in the locking recess engage, do not fill the locking recess completely because a distance is formed between them. The blocking element then prevents a relative rotation of the eccentric sleeve to the connecting rod in one of the directions of rotation by abutment at one end (with respect to the extension along the orbit) of the locking recess and the backstop a relative rotation in the other direction of rotation by a stop on the

corresponding other end of the Sperrvertiefung.

In order to achieve an automatic function of the Rücklaufsperrelements can be provided that it is formed on the side facing the locking element so bevelled that this as a result of contact with the edge of the locking recess of the

Locking recess is moved out, said moving out further preferably leads to an (increasing) bias of a spring element. This bias of the spring element can then ensure a re-engagement of the return locking element in the / a locking recess when this is again or another locking recess positioned as a result of rotation of the eccentric sleeve corresponding to the backstop element.

In a preferred embodiment of an internal combustion engine according to the invention with active adjusting device, at least two coupling devices may be provided, wherein the second (in particular dissolved) position of the coupling element of a first of the

Coupling devices by means of the adjusting device in a first Drehausrichtung the eccentric sleeve with respect to the connecting rod is adjustable and the second (in particular dissolved) position of the coupling element of a second of the coupling devices by means of

Adjustment device is adjustable in a second Drehausrichtung the eccentric sleeve with respect to the connecting rod. Such an embodiment may cause or inhibit a

Take along the eccentric sleeve by the crankshaft in the at least two

Drehausrichtungen or simplify these Drehausrichtungen out and allow in particular by a comparatively simple configured locking and / or adjusting device.

In particular, this can also make it possible for a (possibly as

Serving stop element) first locking element of the locking device, by means of which the eccentric sleeve is lockable in a first Drehrerichtung with respect to the connecting rod, and a (optionally serving as a stop element) second locking element of the locking device, by means of which the eccentric sleeve is lockable in a second Drehrerichtung with respect to the connecting rod by means a common actuating element are actuated alternately. The actuating element may preferably be designed such that it is pivotable about a pivot pin, which is part of a screw, with the two connecting rod eye forming parts of the connecting rod are connected. The actuator would then be part of the connecting rod and would be moved during operation of the internal combustion engine with this. By using a screw, with a two-part in a known manner

Connecting rod is held together, as a rotary bearing element for the actuating element, an additional mass, resulting from the integration of the actuating element in the connecting rod, are kept low.

In a further preferred embodiment of the internal combustion engine according to the invention may also be provided that the actuating element also serves as a stop element of the coupling devices, by means of which the coupling elements can be moved preferably in the respective one dissolved state of the associated coupling device corresponding position. This dual function for the actuator can be a relatively simple structural embodiment of the invention

Internal combustion engine lead.

In particular, to achieve the most secure blocking of the eccentric sleeve in one of the Drehausrichtungen with respect to the connecting rod can be provided that the actuating element can be secured in position in two actuating end positions by means of a latching fuse. These

Ratchet device is preferably designed such that these by an active

Exposure to the goal of switching the actuator by only a force is releasable, but this requires forces are required, which do not act in a corresponding direction on the actuator in a normal operation of the internal combustion engine.

An actuation of the actuating element can preferably be effected by means of an actuating rail. An "actuating rail" is understood to mean a guide element which is positioned or positionable such that the actuating element is moved along the crankshaft at least in sections along this rotation, the actuating element being movable from a first position to a second position for actuation of the actuating element. After such movement of the operating rail, a subsequent movement of the operating element leads to contact with a guide surface of the actuating rail, whereby the actuating element is displaced or pivoted and thereby switched over Housing of the internal combustion engine to be fixed or not moved at least as a result of a different type of attachment with the crankshaft or the connecting rod, so that there is no increase of moving masses for the operation of the internal combustion engine by the operating rail. Particularly preferably it can be provided that the operating rail is pivotally attached to a particular housing of the internal combustion engine, because characterized compared to a likewise possible embodiment with a slidably attached to particular the housing operating rail a simplified operation by means of one of the operating rail associated (for example, hydraulic,

pneumatic, electromotive or electromagnetic) actuator can be enabled.

For a possible shock-free operation of the actuating element by the actuating rail may preferably be provided that the actuating rail forms a both sides arcuately tapered (i.e., narrowing) guide groove for the actuating element. In this case, the arcuate shape may preferably be designed such that the direction of movement of the actuating element, as long as it is moved along the actuating rail, is aligned at all times as tangentially as possible.

Further preferably, it may be provided that the safety catch, which is preferably provided in the case of the internal combustion engine according to the invention, is designed for the actuating element such that the actuating element does not contact the actuating rail in the actuating end positions. Friction losses due to cyclical grinding of the actuator along the guide rail when the actuator in one of its

Operating end positions is (whatever may be the case when just no switching of the compression ratio of the internal combustion engine takes place, and thus during most of the operating time of the internal combustion engine), can be avoided, which is not only positive for the wear of the actuator and the Actuating rail but can also affect the acoustic behavior of the internal combustion engine.

In a particularly preferred embodiment, one with at least two

Clutch devices provided internal combustion engine according to the invention can

be provided that

- In the first Drehausrichtung the eccentric sleeve with respect to the connecting rod, in which the second position of the coupling element of the first coupling device by means of the associated Adjusting device is set, the second position of the coupling element of the second coupling device is adjusted by means of a passive adjusting element and

- In the second Drehausrichtung the eccentric sleeve with respect to the connecting rod, in which the second position of the coupling element of the second coupling device by means of

associated adjusting device is set, the second position of the coupling element of the first coupling device is adjusted by means of a passive adjusting element.

This makes it possible in particular that in each of the Drehausrichtungen only one of the coupling devices must be actively influenced to keep them open or close, while the other coupling device is automatically kept open by the passive adjustment exclusively due to the respective Drehausrichtung the eccentric sleeve. Will then be actively influenced in the respective Drehausrichtung

Coupling device closed, can be caused by this coupling device entrainment of the eccentric sleeve (in a relatively small angular range of rotation of the

Eccentric sleeve with respect to the connecting rod) to overcome the other

Coupling device open holding passive adjustment effect, so that

then both coupling devices ensure the entrainment of the eccentric sleeve by the crankshaft until the corresponding other Drehausrichtung is reached. Then, the previously held by means of the passive adjusting element open coupling device can be actively influenced, while the previously actively influenced coupling device is held open by the associated passive adjustment.

In a further preferred embodiment of an internal combustion engine according to the invention with (at least) two blocking elements, which can be actuated alternately by a common actuating element, it can also be provided that

- In one of the Drehausrichtungen the eccentric sleeve relative to the connecting rod the second

Locking element is held by means of the actuating element in a release position, while the first locking element by means of a supported between the locking elements

Spring element is acted upon in a (the eccentric sleeve in one of the Drehausrichtungen blocking) locking position and

- In one / the other Drehausrichtung the eccentric sleeve relative to the connecting rod, the first locking element is held by means of the actuating element in a release position, while the second locking element is acted upon by means of the spring element in a locking position.

This can be a structurally advantageous embodiment for the operation of both

Locking elements provided actuator can be achieved. The indefinite articles ("a", "an", "an" and "an"), in particular in the patent claims and in the description generally describing the claims, are to be understood as such and not as numerical words. Correspondingly thus concretized

Components are thus to be understood that they are present at least once and may be present more than once.

The present invention will be explained in more detail with reference to embodiments shown in the drawings. In the drawings shows:

1 shows a partial perspective cross section through the relevant components of an internal combustion engine according to the invention in a first embodiment;

Fig. 2: in isolation, the for a change in the compression of

Internal combustion engine relevant components in a perspective view;

FIG. 3 shows the components according to FIG. 2 in a further perspective view; FIG.

Fig. 4: the components according to FIGS. 2 and 3 (but without operating rail of

Internal combustion engine) in a further perspective view;

FIG. 5 shows the components according to FIG. 4 in a further perspective view; FIG.

6 shows the components according to FIGS. 4 and 5 in a further perspective view;

7 shows in a detail a view from below of the components according to FIGS. 4 to 6 with an actuating element of the internal combustion engine in a first embodiment

Actuating position;

Fig. 8: a radial section through a portion of a crankshaft, a connecting rod, a

Eccentric sleeve, an adjustment and a locking device and two

Clutch devices of the internal combustion engine, wherein a first locking element of the locking device in a locking position and a second locking element of

Locking device is in a release position;

9 shows a view according to FIG. 7 with the actuating element in a second

Actuating position; a view according to Figure 8, but now with the first locking element is in a release position and the second locking element in an intermediate position. a view according to FIG. 10, but now the second locking element is in a blocking position; a cross-section through the components according to FIGS. 7 to 1 1;

Fig. 13: in isolated representation, the actuating element of the internal combustion engine in one

perspective view;

14 shows a partial perspective cross section through the relevant components of an internal combustion engine according to the invention in a second embodiment;

FIG. 15 shows the crank mechanism of the internal combustion engine according to FIG. 14 in a side view; FIG.

FIG. 16 shows the detail marked XVI in FIG. 15 in enlarged and partially cutaway view; FIG.

Fig. 17: in isolation, the for a change in the compression of the

Internal combustion engine relevant components (with the exception of the crankshaft) of the internal combustion engine according to FIG 14 in a perspective view. and

FIG. 18 shows the components according to FIG. 17 in a further perspective view. FIG.

FIGS. 1 to 13 show an internal combustion engine according to the invention, for example a gasoline or diesel engine, in a first embodiment. This comprises, according to FIG. 1, a cylinder crankcase 10, within which one or more cylinders 12 are formed. At the upper end of the cylinder crankcase 10 in FIG. 1, an unillustrated cylinder head connects to this, while the lower end of the cylinder crankcase 10 is provided for connection to an oil pan, also not shown. An

Crankshaft 14 of the internal combustion engine receiving crankshaft space 16 would then be formed substantially fully closed. Within the (or each) cylinder 12, a piston 18 is movably mounted axially (with respect to a longitudinal axis 20 of the cylinder 12 and the piston 18). An upper side of the piston 18, the so-called piston crown, defines with the cylinder head a combustion chamber in which a fuel / fresh gas mixture is burned during a working cycle during operation of the internal combustion engine in order to perform work. A pressure increase within the combustion chamber as a result of the combustion leads in a known manner to a downward movement of the piston 18, which is translated by means of a connecting rod 22 into a rotational movement of the crankshaft 14 rotatably mounted within the cylinder crankcase 10. For this purpose, the upper end of the connecting rod 22 is pivotally mounted on the piston 18, for which purpose the connecting rod 22 forms a first, so-called small connecting rod eye 38 (see Fig. 15) which rotatably receives a piston pin 24 of the piston 18. Furthermore, the lower end of the connecting rod 22 with a there also formed, so-called large connecting rod eye 26 (see.

2) are rotatably mounted on a crank pin 30 arranged decentrally with respect to an axis of rotation 28 of the crankshaft 14 (cf., in particular, Fig. 15), so that the pressure forces acting on the piston crown, which are transmitted to the crank pin 30 via the connecting rod 22, generate a torque about the axis of rotation 28 of the crankshaft 14.

As is apparent in particular from FIG. 15, such a crankshaft 14 comprises cylindrical bearing sections 32 which are arranged coaxially with respect to the axis of rotation 28 of the crankshaft 14 and, on the one hand, the connection of adjacent crankpins 30 (in a multi-cylinder internal combustion engine) with one another and, on the other hand, at least partially serve the rotatable mounting of the crankshaft 14 within the cylinder crankcase 10. The rotatably mounted within the large connecting rods 26 of the connecting rod 22 crank pin 30 are bounded on both sides by disk-shaped portions of the crankshaft, which form the so-called crank webs 34 which connect the crank pin 30 with the bearing portions 32, and the other the crank webs 34 with respect to the Form rotational axis 28 radially opposite balancing masses 36, whereby free mass forces and

Mass moments during the rotation of the crankshaft 14 should be avoided as possible.

In order to increase the compression ratio during operation of the internal combustion engine, i. the ratio of the volume of the combustion chamber in the bottom dead center of the piston 18 to the volume at the top dead center of the piston 18 to be able to change in two stages, is provided, the /

Crank pin 30 with the interposition (in each case) of an eccentric sleeve 40 within the / the large Pleuelauges / connecting rod 26 to store. The (each) eccentric sleeve 40 comprises a tubular support portion 42, the cylindrical inner surface of which serves as a sliding surface for the rotational support of the crankpin 30 received therein and the cylindrical surface thereof Outer surface serves as a sliding surface for the rotary bearing of the eccentric sleeve 40 within the large connecting rod 26 of the associated connecting rod 22. The inner and the outer surface of the bearing portion 42 are not coaxial but radially offset by a defined distance from each other, whereby the distance between the pivot or rotation axis 44 of the small connecting rod to the axis of rotation 46 of the cylindrical inner surface of the eccentric sleeve and thus the distance between the piston 18 and the associated crank pin 30 in response to the Drehausrichtung the eccentric sleeve 40 within the large connecting rod 26 changes.

At the two longitudinal axial ends of the tubular bearing portion 42 of the

Eccentric sleeve 40 in each case a limiting section 48 via, each of a

Ring disc is formed, which extends from the storage portion 42 radially outward and thereby limits a mobility of the eccentric sleeve 40 within the large connecting rod 26 in the axial direction with respect to the longitudinal axis 50 of the large connecting rod 26.

By means of a locking device 52, the rotatability of the eccentric sleeve 40 can be blocked within the large connecting rod eye 26 of the connecting rod 22 in two defined Drehausrichtungen, wherein provided in the present embodiment, the two Drehausrichtungen the smallest and the largest distance between the piston 18 and the associated crank pin 30 correspond.

As can be seen in particular from FIGS. 8 to 11, the blocking device 52 comprises two mutually coaxially aligned blocking elements 56 which are displaceably arranged within a cylindrical receiving opening 54 of the connecting rod 22. The receiving opening 54 is at the outermost end (forming the large connecting-rod eye 26). End of the connecting rod 22 and thus positioned in extension of a connecting rod shaft 58 of the connecting rod 22. In particular, it may be provided that the longitudinal axis 60 of the connecting rod 22 passes through the receiving opening 54 and in particular also crosses the longitudinal axis of the receiving opening 54. Between the two locking elements 56, a biased spring element 62 is arranged in the form of a cylindrical helical spring, the 56 and the two locking elements away from each other in the direction of the associated end of the receiving opening 54 and in the direction of the adjoining boundary portion 48 of the eccentric sleeve 40th

applied. The axial mobility of the locking elements 56 within the receiving opening 54 is variably limited in dependence on the position of an actuating element 64. For this purpose, in each case a driving projection 66 of the actuating element 64 shown in isolation in FIG. 13 engages in a (with respect to the longitudinal axis of the receiving opening 54 or the

Movement axis of the locking elements 56) circumferential driving groove 68 of the locking elements 56, whereby on the one hand a mobility of the locking elements 56 within the

Receiving opening 54 limited and this on the other for a change of the

Compression ratio in which the internal combustion engine can be operated, can be moved by switching the operating member 64 between two actuation end positions within the receiving opening 54.

FIGS. 7 and 8 show the actuating element 64 in a first embodiment

Actual end position, in addition, a first of the locking elements 56, which is shown in Figs. 8, 10 and 1 1 right, in a through hole (corresponding to the embodiment of FIGS. 7 to 1 1) or edge-side recess (corresponding to the embodiment 1 to 6) can engage in the associated limiting section 48 of the eccentric sleeve 40 formed locking recess 70, provided that the eccentric sleeve 40 is in the corresponding Drehausrichtung with respect to the connecting rod 22 and the large connecting rod 26. On the other hand, FIGS. 9 and 11 show the actuating element 64 in the second actuation end position, in which the second of the locking elements 56, which is shown on the left in FIGS. 8, 10 and 11, fits into a corresponding limiting section 48 of the eccentric sleeve 40 formed locking recess 70 can engage when the eccentric sleeve 40 is in the associated Drehausrichtung, which is offset with respect to the first Drehausrichtung the eccentric sleeve 40 (as shown in FIGS. 8 and 10) by approximately 180 °. In these two Drehausrichtungen the eccentric sleeve 40, which are lockable by means of the locking device 52, the distances between the piston 18 and the associated differ

Crankpin 30 due to the eccentric design of the eccentric sleeve 40th This

different distances are also apparent from a comparison of Figs. 8 and 1 1, from which the different wall thicknesses of the tubular bearing portion 42 of the eccentric sleeve 40 in the portion between the crank pin 30 and the

Locking device 52 receiving portion of the connecting rod 22 can be seen. In the

Drehhausrichtung according to FIG. 8, the wall thickness of the corresponding portion of the bearing portion 42 of the eccentric sleeve 40 is greater than in the Drehausrichtung according to FIG. 1 1, whereby the distance between the crank pin 30 and the piston 22 in the

Drehausrichtung according to FIG. 8 is smaller than that in the Drehausrichtung according to FIG. 1 1. Fig. 10 shows the positions of the locking elements 56 after switching of the actuating element 64 of the inter alia in Fig. 7 shown first Betätigungsendstellung in the example shown in FIG. 9 second Betätigungsendstellung, but even before the eccentric sleeve 40 of the Drehausrichtung according to Fig. 8 has been rotated in the Drehausrichtung according to FIG. 1 1. In Fig. 10 it is shown that the first blocking element 56 shown on the right is in a release position in which this out of engagement with the

associated locking recess 70 of the eccentric sleeve 40 and also in a defined distance with respect to the associated boundary portion 48 of the eccentric sleeve 40 is arranged. Moving the first blocking element 56, shown on the right, starting from the blocking position according to FIG. 8 into the release position according to FIG. 10, is achieved by switching over the actuating element 64 from a first actuating end position according to FIG. 7 to the second actuating end position according to FIG 9 reaches, wherein this is pivoted about a pivot axis 72. It takes the appropriate

Mitnahmevorsprung 66 of the actuating element 64 as a result of contact with the inner boundary wall of the driving groove 68 with the first blocking element 56 and shifts this within the receiving opening 64 in the direction of its longitudinal axial center.

At the same time, the second locking element 56 shown on the left is given the opportunity to move further in the direction of the corresponding end of the receiving opening 64, this movement being supported by the bias of the locking elements 56 supported by the movement of the first locking element 56 in the direction of the longitudinal axial Center of the receiving opening 64 further biased spring element 62 is effected. As long as the eccentric sleeve 40 is not yet in the illustrated in Fig. 1 1 second

Dredrehrichtung has been rotated, this mobility of the second locking member 56 is limited due to contact with the inside of the associated limiting portion 48 of the eccentric sleeve 40. Only shortly before reaching the second Drehrerichtung the second locking element 56 can engage in the then correspondingly associated associated locking recess 70 and thus moved into its blocking position shown in FIG. 1 1.

When switching the actuating element 64 again, then the u.a. in Fig. 9 illustrated second Betätigungsendstellung in the u.a. in Fig. 7 illustrated first

Betätigungsendstellung, is in accordance with reverse order, the second

Locking element 56 moves into the associated release position and the first locking element 56 is released, which in turn can engage in the associated locking recess 70 as soon as the eccentric sleeve has been rotated again by about 180 ° within the large connecting rod eye 26. The connecting rod 22 comprises two parts screwed together, one the small connecting rod 38, the connecting rod shaft 58 and a half of the large connecting rod eye 26 forming

Pleuelgrundkörper 74 and a second half of the large connecting rod 26 forming and the locking device 52 integrating connecting rod 76. This bipartite of the connecting rod 22 in the region of the large connecting rod 26 allows the connection of the connecting rod 22 with the corresponding bearing pin 30 of the one-piece crankshaft 14 during assembly the internal combustion engine. The parting plane between the Pleuelgrundkörper 74 and the

Connecting rod cover 76 is perpendicular to the longitudinal axis 60 of the connecting rod 22nd

(or the connecting rod shaft 58). Furthermore, the axis of rotation 50 of the eccentric sleeve 40 extends within the large connecting rod 26 within this parting plane, resulting in a radial orientation of this parting plane with respect to the large connecting rod 26. As can be seen in particular in FIG. 12, the screw of one of the screw connections 78 between the connecting rod main body 74 and the connecting rod cover 76 is used as a pivot pin for the actuating element 64. The pivot axis 72, about which the actuator 64 is pivotable to be moved back and forth between the two Betätigungsendstellungen, thus corresponds to the longitudinal axis of the screw of this screw 78th

A backup of the actuating element 64 in its two Betätigungsendstellungen by means of a latching fuse 80, which, according to FIGS. 12 and 13 of one of a

Spring element 82 loaded in a guide opening of the connecting rod 22 and the connecting rod cover 76 movably guided detent ball 84 in conjunction with one of two juxtaposed, cup-shaped detent recesses 86 which are integrated into the adjacent portion of the actuating element 64 is formed. When switching the actuating element 64 between its Betätigungsendstellungen each locking ball 84 must be raised under further bias of the associated spring element 82 to overcome the arranged between the two locking recesses 86 web 88. For this purpose, a switching torque (about the pivot axis 72 of the actuating element 64) is required, which is not caused by forces usually occurring during operation of the internal combustion engine. An unwanted, automatic switching of the actuating element 64 can thus be avoided by the safety catch 80. On the other hand, only the application of a corresponding switching torque to the actuating element 64 is required for switching, without a positively acting lock would have to be solved.

An actuation of the actuating element 64 by means of a pivotable on the

Cylinder crankcase 10 fastened actuating rail 90, as shown in FIGS. 1 to 3 is shown. In this case, the actuating rail 90 is shown in Fig. 1 in the manner of an exploded view spaced from the junction on the cylinder crankcase 10 and thus of its actual functional position within the crankshaft space 16. In its actual functional position (see Figures 2 and 3), the actuating rail 90 is located so close to the axis of rotation 28 of the crankshaft 14, that the actuating element 64 connected to the connecting rod 22 with one of them

Guide member 92 is disposed in the position corresponding to the bottom dead center of the piston 18 and at least over a defined angular range before reaching this position within a formed of two side walls of the operating rail guide groove 94. The width of the guide groove 94 assumes thereby starting from an inlet, i. the end at which the guide member 92 of the actuating element 64 enters the guide groove 94 in the context of each revolution of the crankshaft 14, continuously from. In addition, the longitudinal extension of the actuating rail 90 to the orbit of the

Guide element 92 of the actuating element 64, which describes this due to a rotation of the crankshaft 14, adapted by means of a curved course, so that

In particular, it may be provided that a distance that the underside of the

Guide element 92 to the groove bottom 96 of the guide groove 94 of the actuating rail 90 complies, remains substantially the same over the course of the movement of the guide member 92 within the guide groove 94. It is preferably provided that the

Guide member 92 of the actuator 64, the groove bottom 96 of the guide 94 contacted at any time.

If the actuating element 64 is in one of its actuating end positions and the actuating rail 90 is in the associated functional position, the guide element 92 of the actuating element 64 will be in contact with one of the inside walls formed by the side walls of the actuating rail 90 during each revolution of the crankshaft 14

Guiding surfaces 98 of the guide groove 94 of the actuating rail 90 guided by the guide groove 94 therethrough. In particular, it can be provided that the guide element 92 is guided at least at the end of the guide groove 94 substantially exactly in the middle between the two side walls. If, however, starting from such a starting position, the actuating rail 90 is pivoted by means of a not shown, driven by a likewise not shown engine control of the engine actuator in the corresponding other functional position, the guide member 92 of the contacted

Actuator 64 the next entering the guide groove 94 through the

Actuate the actuating rail 90 in the orbit of the guide member 92 gerrückte guide surface 98 so that the guide member 92 along this guide surface 98 out while the actuating element 64 is moved or pivoted due to the narrowing guide groove 94 in the direction of its other end of the actuator. In this case, caused by the contact with the corresponding guide surface 98

Pivoting movement of the actuating element 64 is only so great that the detent ball 84 of the safety catch 80 is moved over the web 88 formed between the two detent recesses 86. The last, relatively small section of the pivoting movement of the

Actuator 64 in its then intended Betätigungsendstellung is achieved by the engagement of the detent ball 84 in the corresponding detent recess 88. As a result, it can be effected that the guide element 92 of the actuating element 64 is still far away from the guide surface 98 of the actuating rail 90 effecting the switchover and thus there is no contact with this or both sidewalls of the actuating rail 90 in the subsequent operation of the internal combustion engine.

The guide surfaces 98 of the operating rail 920 are formed curved such that the guide member 92 of the actuating element 64 after switching the

Actuating rail 90 runs in the tangential direction on the corresponding guide surface 98, whereby a switching of the actuating element 64 can be achieved with a uniformly increasing as possible force curve. This can have an advantageous effect on the life of the components involved and on the acoustic behavior of the internal combustion engine.

To allow a safe and fast rotation of the eccentric sleeve 40 between the two lockable by the locking device 52 Drehausrichtungen after the

Actuator 64 by means of the actuating rail 90 of one of

Operating end positions has been pivoted into the other of the actuating end positions, the internal combustion engine according to the invention comprises two non-positively acting

Coupling devices 100, by means of which the eccentric sleeve 40 is temporarily coupled to the crankshaft 14 in order to rotate the eccentric sleeve 40 relative to the connecting rod 22 and the large connecting rod eye 26. Each of the coupling devices 100 comprises a sickle-shaped or partially annular coupling element 102, which on the

Outside each one of the boundary portions 48 of the eccentric sleeve 40 and thus arranged in a formed between the eccentric sleeve 40 and the adjacent crank arm 34 of the crankshaft 14 coupling gap 104. It is an end of the

Coupling member 102 rotatably in the associated limiting portion 48 of

Eccentric sleeve 40 is fixed and the coupling element extends, starting from this pivot bearing in the direction of rotation 106 of the eccentric sleeve, these in the operation of the Internal combustion engine (and in a blocking in one of the Drehausrichtungen) relative to the associated crank webs has (see Fig. 2 and 3).

As can be seen for example from FIGS. 8, 10 and 11, the gap width of the

Coupling gap 104 in the radial direction to the outside, which by a corresponding inclination of serving as a clutch surfaces (the eccentric sleeve 40 facing) inner sides of the crank webs 34 by an angle of approximately 3 ° relative to an orientation perpendicular to the axis of rotation 50 of the eccentric sleeve 40th is achieved within the large Pleuelauges 26 or the rotation axis 46 of the crank pin 30 within the eccentric sleeve 40. The cross section of each of the coupling elements 102 is correspondingly tapered or wedge-shaped, so that a parallel alignment of the

Coupling surfaces of the coupling elements 102 to the coupling surfaces formed by the crank cheeks 34 results. The coupling elements 102 of both coupling devices 100 are each acted upon by a prestressed spring element 108 in the direction radially outward and thus in the narrowing coupling gap 104 inside. These

Spring loading results in output loads for the coupling devices 100, through which the coupling surfaces of the coupling elements 102 to the coupling surfaces of the crank webs 34 and the eccentric sleeve 40 (from the outside of the

Limiting portions 48 of the eccentric sleeve 40 are formed) are pressed. The output loads thus generated lead to frictional forces, which are opposite to a relative movement between the eccentric sleeve 40 and the crank webs 34 and their direction of action is such that they additionally a moment about the respective pivot bearing of the coupling elements 102 in the direction of further pivoting outwards and thus an additional Pulling into the respective narrowing coupling gap 104 effect. Thereby, a self-reinforcement of the non-positive effects of

Clutch devices 100 achieved in the respective closed state.

During operation of the internal combustion engine and at a blocking of the eccentric sleeve 40 in one of the Drehausrichtungen the coupling devices 100 are usually open by the coupling elements 102 are pivoted by a respective contact with a stop element 1 10 so far under further bias of the respective spring element 108 inward, that the smallest possible adhesion between at least the coupling surfaces of the crank webs 34 and the adjacent coupling surfaces of the coupling elements 102 is given. In each case, that coupling element 102, which is on the one

Limiting portion 48 of the eccentric sleeve 40 is rotatably mounted in the result of the corresponding selected Betätigungsendstellung of the actuating element 64 the associated locking element 56 engages in the locking recess 70, is deflected by means of an associated stop element 1 10 of the actuating element 64 inwardly, while a deflection of the respective other coupling element 102 by means of a passive, immovable stop element 1 10 takes place.

Now, if the actuator 64 is switched, the previously held by this held held coupling element 102 is released so that this pivots due to the spring load to the outside and thus in the associated narrowing coupling gap 104, whereby at least the corresponding coupling device 100 is closed. This closed coupling device 100 causes then initially alone co-rotation of the eccentric sleeve 40 with the relative to the large connecting rod 26 rotating crank arms 34. This co-rotation causes a release of the other coupling element 102 of the

deflecting contact with the passive stop element 1 10, so then also this coupling element 102 due to the spring load in the narrowing

Clutch gap 104 is pressed and thus this coupling device 100 is closed. For the rest of the rotation of the eccentric sleeve by 180 ° to the other Drehausrichtung then cause both coupling devices 100, the positive coupling of

Eccentric sleeve 40 to the associated crank webs 34 of the crankshaft 14. Shortly before reaching the new Drehausrichtung the eccentric sleeve 40 then engages the other

Locking element 56, as already described with reference to Figures 10 and 1 1, in the locking recess 70 of the associated boundary portion 48 of the eccentric sleeve 40 and the

Coupling elements 102 of both coupling devices 100 then run on the

corresponding stop elements 1 10, on the one hand due to the switching of the

Actuator 64 disengaged second stop element 1 10 of the actuator 64 and on the other hand on the eccentric sleeve 40 on both sides superior passive stop element 1 10, which in turn under renewed bias of

Spring elements 108 pivoted inward and thus the coupling devices 100 are released. The internal combustion engine can then continue to be operated with a modified compression ratio, wherein the eccentric sleeve 40 is locked in the new Drehausrichtung relative to the connecting rod 22 and due to the dissolved coupling devices 100 again largely frictionless relative to the crank webs 34 is rotatable.

Due to the high speeds with which internal combustion engines, which are provided for example for driving motor vehicles, operated, resulting in high

Differential angular velocities between the temporarily coupled by means of the coupling devices 100 with the crank cheeks 34 eccentric sleeve 40 and the locking device 52nd In order to ensure a secure engagement of each spring-loaded during the change in the Drehausrichtung against the inside of the associated Begrenzungsabschnitts 48 of the eccentric sleeve 40 depressed locking element 56 despite these high differential angular velocities, each of the locking recesses 70 with respect to an orbit of the associated locking element 56 (at relative to the connecting rod 22 rotating eccentric sleeve 40) has a larger dimension than that provided for engagement in the locking recess 70 part of the blocking element 56. The locking recesses 70 are as

arcuate, elongated through holes or recesses formed. The blocking elements 56 can thus engage not only in a concrete Drehrerichtung but in a larger angular range in the associated locking recesses 70, so that this despite relatively high differential angular velocities and despite the inertia with which the locking elements 56 due to the spring load in the direction of

associated Sperrvertiefungen 70 are accelerated, with sufficient certainty.

The larger dimensions of the locking recesses 70 compared to those in this

engaging parts of the locking elements 56 leads despite a blocking by one of

Locking elements 56 in principle to a (limited) rotational mobility between the eccentric sleeve 40 and the large connecting rod eye 26. To eliminate this rotational mobility or at least reduce as much as possible each blocking element 56 is still attached to the connecting rod 22 and concretely the connecting rod cover 76, passive backlash element. 1 12, which, when the associated blocking element 56 at the respect to the

Direction of rotation 106 of the eccentric sleeve 40 engages relative to the crank webs 34 front end of the associated locking recess 70, in the region of the other end also engages in this locking recess 70 and thus together with the locking element 56, the eccentric sleeve 40 largely free of play with the connecting rod 22 connects. Moving out of engaging in a locking recess 70 backstop element 1 12, although the associated locking element 56 due to a switching of the actuating element 64 from the

associated Sperrvertiefung 70 has been moved out, is automatically achieved in that the backstop elements 1 12 are each formed with an oblique surface that they then effected entrainment of the eccentric sleeve 40 by the crankshaft 14 in contact with the edge of the respective locking recess 70 Another

Preload a spring element 1 14 are deflected. For a structurally advantageous integration of the two return blocking elements 1 12 in the connecting rod 22 is provided that these are each attached to a free end of a leg of the formed in the form of a U-shaped leaf spring spring element 1 14 and the spring element 1 14 in the region arcuate portion in which it is not deflected, is attached to the actuator 64.

As the connecting rod 22 in the region of the large connecting rod eye 26 and the eccentric sleeve 40 is formed of two parts or half shells, wherein the dividing plane 1 16 between these parts is preferably arranged such that the axis of rotation 46 of the

Crankpin 30 within the eccentric sleeve 40 or the axis of rotation 50 of

Eccentric sleeve 40 within the large Pleuelauges 26 within this parting plane 1 16 extends. For a possible advantageous installation of the eccentric sleeve 40 is further provided that bearing openings (and in particular the longitudinal axes thereof), which serve the pivotal mounting of the coupling elements 102 in the associated Begrenzungsabschnitten 48 of the eccentric sleeve 40, 16 are also arranged in this parting plane. The same applies to radially with respect to one of the axes of rotation 46, 50 of the eccentric sleeve aligned

Guide openings 1 18 for the deflectable ends of the arcuately guided on the inner sides of the associated coupling elements 102 and rotationally secured in the region of the rotary bearings of the coupling element integrated spring elements 108. A separate connection of the two parts of the eccentric sleeve 40 is not required, because these due to the arrangement within the large Pleuelauges 26 are held together.

The illustrated in FIGS. 14 to 17 second embodiment of an internal combustion engine according to the invention differs from the first embodiment shown in FIGS. 1 to 13 essentially only in terms of the design of the coupling devices 100 and actively releasable for releasing the coupling devices 100 Einsteilvorrichtung.

In this internal combustion engine, two positively acting coupling devices 100 are provided, each having a coupling element 102 which is resiliently acted upon in a closing the respective coupling device 100 and thus the eccentric sleeve 40 to a rotational movement of the crankshaft 14 coupling position. While in the embodiment according to FIGS. 1 to 13 coupling elements 102 are provided, which are acted upon by means of separate biased spring elements 108, the coupling elements 102 are formed in the embodiment according to FIGS. 14 to 17 itself elastically deflectable. Specifically, these are each formed in the form of a spiral spring, one end of which engages in an opening in the associated limiting portion 48 of the eccentric sleeve 40 and is secured in position, and extending from this end by more than 360 ° and concretely by about 450 ° formed by the eccentric sleeve 40 storage opening for the associated crank pin 30 of the crankshaft 14 is guided around. The second end of each the helical spring-shaped coupling elements 102 is angled and supported with this angled section edge on the associated boundary portion 48 of the eccentric sleeve 40 from. The geometry of the spiral spring-shaped coupling elements 102 is selected such that they are elastically widened at a concern with the angled ends at the edges of the limiting sections 48 and thus biased, which leads to an endeavor of the coupling elements 102 to curl narrower or to a smaller diameter , This leads to a constructive elastic loading of the coupling elements 102, because they thereby automatically pull into the coupling gaps 104 (see FIG 34 cause, unless they are radially expanded by a stop against stop elements 1 10 and thus the frictional connection between the coupling elements 102 and the coupling surfaces of the crank webs 34 and the eccentric sleeve 40 is repealed.

Another difference of the internal combustion engine according to FIGS. 14 to 18 to that according to FIGS. 1 to 13 is that the activatable and deactivatable

Stop elements 1 10, of which in each case one of the two Drehausrichtungen the

Eccentric sleeve 40, which are lockable by means of the locking device 52, one acts on one of the coupling elements 102, while at the same time the other coupling element 102 is radially expanded by contact with a passive stop element 1 10 (see Fig. 18), not by the actuating element 64th but are formed by the respective blocking element 56. For this purpose, it is provided that the corresponding blocking element 56, which also engages in the associated locking recess 70 of the eccentric sleeve 40, as far as the

Through hole in the corresponding limiting portion 48 of the eccentric sleeve 40 formed locking recess 70 protrudes into the associated coupling gap 104 that with closed coupling devices 100 and thus at a carry the eccentric sleeve 40 by the crankshaft 14 at the edge of the corresponding

Limiting portion 48 supported end of the corresponding coupling element 102 upon reaching the corresponding Drehausrichtung the eccentric sleeve 40 on the in the

Coupling gap 104 protruding part of the corresponding locking element 56 runs and thereby this coupling element 102 is radially expanded (see Fig. 17). At the same time the corresponding end of the other coupling element 102 runs on the outside on the associated passive stop element 1 10 and is also widened. Both are

Coupling devices 100 open and a frictional connection between the eccentric sleeve 40 positively connected coupling elements 102 and the crank webs 34 of the crankshaft 14 is substantially interrupted.

If, starting from such a starting position in which the internal combustion engine is operated at a constant compression ratio, the actuating element 64 is switched over by means of the actuating rail 90 in accordance with the procedure in the internal combustion engine according to FIGS. 1 to 13, again the locking element 56 is in a locking position moved to a release position. The then by this blocking element 56 then no longer widened coupling element 102 then causes first alone a driving the eccentric sleeve 40 through the crankshaft 14, whereby in a first, relatively small portion of the rotation of the eccentric sleeve 40 relative to the large connecting rod eye 26 and the second coupling element 102 except Engagement with the passive stop element 1 10 is brought. This second coupling element 102 then also couples the eccentric sleeve 40 frictionally to the associated crank cheek 34 of the crankshaft 14. The second locking elements 56 engaging in the associated locking recess 70 upon reaching the other rotational orientation of the eccentric sleeve 40 then expands the associated coupling element 102 radially, while the other coupling element 102 is radially expanded by the associated passive stop element 1 10, so that in turn both

Clutch devices 100 are opened.

Cylinder crankcase

cylinder

crankshaft

crankshaft space

piston

Longitudinal axis of the cylinder / piston

pleuel

piston pin

big connecting rod eye

Rotation axis of the crankshaft

crank pin

Bearing section of the crankshaft

crank web

Compensation mass of the crankshaft

small connecting rod eye

eccentric

Storage section of the eccentric sleeve

Rotation axis of the small connecting rod eye

Rotation axis of the cylindrical inner surface of the eccentric sleeve

Limiting section of the eccentric sleeve

Longitudinal axis of the large connecting rod eye / axis of rotation of the cylindrical outer surface of the eccentric sleeve

locking device

Receiving opening of the connecting rod

blocking element

connecting rod shaft

Longitudinal axis of the connecting rod

Spring element of the locking device

actuator

Carrying projection of the actuating element

Takeover of the barrier element

blocking recess

Pivot axis of the actuating element 74 Pleuelgrundkörper

76 connecting rod cover

78 screw connection between the Pleuelgrundkörper and the connecting rod cover

80 snap lock

82 Spring element of the safety catch

84 detent ball of the safety catch

86 latching recess of the safety catch

88 Bar of the safety catch

90 operating rail

92 guide element of the actuating element

94 guide groove of the operating rail

96 groove base of the guide groove

98 guide surface of the guide groove

100 coupling device

102 coupling element

104 coupling gap

106 Direction of rotation of the eccentric sleeve relative to the crank webs

108 spring element of the coupling device

1 10 stop element

1 12 return blocking element

1 14 Spring element for the backstop element

1 16 Parting plane between the parts of the eccentric sleeve

1 18 guide opening for the spring element of the coupling device

Claims

claims

1. Internal combustion engine with a cylinder (12), one within the cylinder (12)

movably guided piston (18), a crankshaft (14) and a piston (18) with a crank pin (30) of the crankshaft (14) connecting the connecting rod (22), wherein within a connecting rod (26) of the connecting rod (22) has a Rotatable crank pin (30)

receiving eccentric sleeve (40) is rotatably mounted in at least two

Drehausrichtungen with respect to the connecting rod (22) by means of a locking device (52) is lockable, characterized by a coupling device (100), by means of which the

Eccentric sleeve (40) is temporarily coupled to the crankshaft (14) to rotate the eccentric sleeve (40) relative to the connecting rod (22).

2. Internal combustion engine according to claim 1, characterized in that the

Coupling device (100) acts positively.

3. Internal combustion engine according to claim 2, characterized in that the crankshaft (14) and the eccentric sleeve (40) each having a coupling surface, which form a coupling gap (104) decreasing in a radial direction gap width, wherein a coupling element (102) in a first position and a second position can be brought, which differ with regard to the radial position within the coupling gap (104) and thus with respect to the contact pressure between the coupling element (102) and the coupling surfaces.

4. Internal combustion engine according to claim 3, characterized in that the

Coupling device (100) is self-reinforcing.

5. Internal combustion engine according to claim 3 or 4, characterized in that the coupling element (102) is acted upon elastically.

6. Internal combustion engine according to one of claims 3 to 5, characterized in that the coupling element (102) assumes the first position in the elastic non-applied state or as a result of a constructive elastic loading, while the second position is adjustable by means of an active adjusting device.

7. Internal combustion engine according to claim 6, characterized in that the adjusting device has an adjustable stop element (1 10) for the coupling element (102) which can be activated and deactivated, wherein it forms a stop for the coupling element (102) in the activated state and in deactivated state forms no stop for the coupling element (102).

8. Internal combustion engine according to one of the preceding claims, characterized

in that a blocking element (56) of the blocking device (52) is also known as

Stop element (1 10) of the coupling device (100) is used.

9. Internal combustion engine according to one of the preceding claims, characterized

characterized in that a blocking element (56) of the locking device (52) in a

Locking recess (70) of the connecting rod (22) or the eccentric sleeve (40) is movable, wherein the locking recess (70) with respect to the orbit of the locking element (56) on which this relative to the blocking recess (70) forming component in a relative rotation between the eccentric sleeve (40) and the connecting rod (22) rotates, has a larger dimension than the intended for engagement in the locking recess (70) part of the locking element (56).

10. Internal combustion engine according to claim 9, characterized by a

Return blocking element (1 12), which together with the blocking element (56) in the

Locking recess (70) can intervene.

1 1. Internal combustion engine according to claim 10, characterized in that the

Return blocking element (1 12) is formed tapered so that this is due to a contact with the edge of the locking recess (70) from the locking recess (70) out movable.

12. Internal combustion engine according to claim 6 or one of the dependent claim 6 claims, characterized by at least two coupling devices (100), wherein the second position of the coupling element (102) of a first of the

Coupling devices (100) by means of the adjusting device in a first

Drehausrichtung the eccentric sleeve (40) relative to the connecting rod (22) is adjustable and the second position of the coupling element (102) of a second of the coupling devices (100) by means of Einsteilvorrichtung in a second Drehausrichtung the eccentric sleeve (40) relative to the connecting rod (22) is adjustable.

13. Internal combustion engine according to claim 12, characterized in that a first blocking element (56) of the locking device (52), by means of which the eccentric sleeve (40) in a first Drehrerichtung relative to the connecting rod (22) can be blocked, and a second blocking element (56 ) of the locking device (52), by means of which the eccentric sleeve (40) in a second Drehrerichtung relative to the connecting rod (22) can be blocked, by means of a common actuating element (64) are actuated alternately.

14. Internal combustion engine according to claim 13, characterized in that the

Actuator (64) is pivotable about a pivot pin, which is part of a screw (78), with the two connecting rod eye (26) forming parts of the connecting rod (22) are connected.

15. Internal combustion engine according to claim 13 or 14, characterized in that the actuating element (64) also serves as a stop element (1 10) of the coupling devices (100).

16. Internal combustion engine according to any one of claims 13 to 15, characterized in that the actuating element (64) in at least two actuating end positions by means of a latching fuse (80) is positionally secure.

17. Internal combustion engine according to any one of claims 13 to 16, characterized in that the actuating element (64) by means of an actuating rail (90) is actuated, which is pivotally mounted thereto to a housing of the internal combustion engine.

18. Internal combustion engine according to claim 17, characterized in that the

Actuating rail (90) forms an arcuate guide groove (94) for the actuating element (64) which tapers on both sides.

19. Internal combustion engine according to claim 16 and claim 17 or 18, characterized

in that the safety catch (80) is designed such that the

Actuator (64) does not contact the operating rail (90) in the operating end positions.

20. Internal combustion engine according to one of claims 12 to 19, characterized in that in the first rotational orientation of the eccentric sleeve (40) relative to the connecting rod (22), in which the second position of the coupling element (102) of the first coupling device (100) is adjusted by means of the adjusting device, the second position of

Coupling element (102) of the second coupling device (100) by means of a passive adjusting element (1 10) is set and

- In the second Drehausrichtung the eccentric sleeve (40) relative to the connecting rod (22), in which the second position of the coupling element (102) of the second

Coupling device (100) is adjusted by means of the adjusting device, the second position of the coupling element (102) of the first coupling device (100) by means of a passive adjusting element (1 10) is set.

21. Internal combustion engine according to claim 13 or one of the dependent of claim 13 claims, characterized in that

in one of the rotational orientations of the eccentric sleeve (40) relative to the connecting rod (22), the second blocking element (56) is held in a release position by means of the actuating element (64), while the first blocking element (56) is connected by means of one between the

Locking elements (56) supported spring element (62) is acted upon in a locking position, and

- In another Drehausrichtung the eccentric sleeve (40) relative to the connecting rod (22) the first locking element (56) by means of the actuating element (64) is held in a release position, while the second locking element (56) by means of the spring element (62) in a Locked position is applied.