DE102013021635A1 - Reciprocating internal combustion engine - Google Patents

Abstract

The invention relates to a reciprocating internal combustion engine for a motor vehicle, comprising a crankcase, having a crank shaft (14) rotatably mounted on the crankcase about an axis of rotation relative to the crankcase and having at least one crankpin (18) and at least one cylinder of the reciprocating piston. Internal combustion engine associated connecting rod (10) which is mounted on the crank pin (18) via an eccentric (22), wherein for varying the compression ratio of the cylinder, a rotation of the eccentric (22) relative to the crank pin (18) and the connecting rod (10) effected is provided with a fixed to the crankcase guide member (26) and on the crankshaft (14) arranged sliding piece (32) are provided which by rotating the crankshaft (14) in cooperation with the guide element (26) movable and due to the interaction in the axial Direction relative to the crankshaft (14) from a first position in at least one second position ve can be pushed, in which by means of the sliding piece (32) an operative connection between the eccentric (22) and the crankshaft (14) and the resulting rotation of the eccentric (22) is effected.

Description

The invention relates to a reciprocating internal combustion engine according to the preamble of patent claim 1.

Such a reciprocating internal combustion engine for a motor vehicle is the DE 103 09 651 A1 to be known as known. The reciprocating internal combustion engine comprises a crankcase and a crankshaft rotatably mounted on the crankcase about an axis of rotation relative to the crankcase and having at least one crankpin. Furthermore, the reciprocating internal combustion engine has at least one connecting rod, which is associated with a cylinder of the reciprocating internal combustion engine. The connecting rod is mounted on the crank pin via an eccentric, wherein for varying the compression ratio of the cylinder, a rotation of the eccentric relative to the crank pin and relative to the connecting rod is effected.

The DE 199 44 668 A1 discloses a device for changing the compression of a reciprocating internal combustion engine, with at least one connecting rod, in whose crankshaft assignable connecting rod a sleeve with a crankshaft passage opening is rotatably arranged. The crankshaft passage opening is arranged eccentrically to the connecting rod. Further, it is provided that the sleeve or the connecting rod for rotating the sleeve has at least one acted upon by a pressure medium working chamber.

By rotating the eccentric so-called gauge of the connecting rod is changeable, so that thereby the compression ratio of the cylinder is adjustable. As a result, for example, the compression ratio can be adapted to different operating points of the reciprocating internal combustion engine. Also the US 2011/0155106 A1 discloses a reciprocating internal combustion engine with at least one variably adjustable compression ratio.

Object of the present invention is to develop a reciprocating internal combustion engine of the type mentioned in such a way that a particularly space-saving and robust adjustment of the compression ratio can be realized.

This object is achieved by a reciprocating internal combustion engine having the features of patent claim 1. Advantageous embodiments with expedient and non-trivial developments of the invention are specified in the remaining claims.

In order to develop a reciprocating internal combustion engine specified in the preamble of claim 1 type such that a particularly space-saving and robust adjustment of the compression ratio can be realized according to the invention a fixed to the crankcase guide element and provided on the crankshaft and provided with this movable sliding piece. The sliding piece is movable by rotating the crankshaft in cooperation with the guide element. As a result of the interaction, the sliding piece is displaceable in the axial direction relative to the crankshaft from a first position to at least a second position. In other words, the sliding piece comes as a result of the rotation of the crankshaft in cooperation with the fixed relative to the crankcase, that is immovable guide member, the sliding piece is displaced in the axial direction relative to the crankshaft from the first position to the second position.

In the second position, an operative connection between the eccentric and the crankshaft and the resulting rotation of the eccentric can be effected by means of the sliding piece. This means that the eccentric as a result of the operative connection between the eccentric and the crankshaft entrained by the crankshaft, that is abruptly entrained, so that the eccentric is rotated relative to the oscillating during the rotation of the crankshaft connecting rod. This rotation of the eccentric relative to the connecting rod and also relative to the crank pin causes a change in the stroke of a piston arranged in the cylinder, which is articulated via the connecting rod with the crankshaft. This change in the stroke in turn causes the change in the compression ratio.

The sliding piece and the guide element allow an active adjustment, that is, control of the compression ratio, which can be realized on existing engine concepts. In particular, it is possible to provide both series and V engines with this compression ratio setting. Other internal combustion engines such as boxer engines can be provided with such adjustability of the compression ratio. This adjustability of the compression ratio can be displayed in a particularly space-saving manner, wherein the basic function of the engine parts, in particular with regard to the kinematics and load capacity remain unchanged. Thus, the adjustability of the compression ratio is particularly robust, so that the function of the reciprocating internal combustion engine is ensured over a long service life.

In addition, it is possible to differentiate the compression ratio Adjust operating points of the reciprocating internal combustion engine, so as to optimize the efficiency of this. As a result, a particularly fuel-efficient operation can be realized with only low CO ₂ emissions.

Further advantages, features and details of the invention will become apparent from the following description of a preferred embodiment and from the drawing. The features and feature combinations mentioned above in the description as well as the features and feature combinations mentioned below in the description of the figures and / or in the figures alone can be used not only in the respectively specified combination but also in other combinations or in isolation, without the scope of To leave invention.

The drawing shows in:

1 a schematic front view of a connecting rod for a reciprocating internal combustion engine, with a large connecting rod in which an eccentric is arranged, via which the connecting rod is to be stored on a corresponding crank pin and a crankshaft, wherein by turning the eccentric relative to the crank pin and relative to Connecting rod a compression ratio of the connecting rod associated cylinder is adjustable;

2 a schematic perspective view of the crankshaft, on the crank pin of the eccentric is arranged in sections, wherein the adjustment of the compression ratio by a housing-fixed guide member and a sliding piece, which is displaceable by means of the housing-fixed guide member relative to the crankshaft in the axial direction, is effected;

3 a schematic and perspective side view of the sliding piece;

4 a schematic perspective view of the guide member;

5 partially a schematic and perspective side view of the eccentric and the sliding piece;

6 partial perspective view of the connecting rod;

7 a detail of another schematic perspective view of the eccentric and the sliding piece;

8th a detail of another schematic perspective view of the connecting rod; and

9 a detail of another schematic perspective view of the eccentric and the sliding piece.

1 shows in a schematic front view with a whole 10 designated connecting rod for a reciprocating internal combustion engine of a motor vehicle. The connecting rod 10 has at its first end a large connecting rod eye 12 and at its second end opposite the first end, an in 1 unrecognizable small eye on. About the small connecting rod eye and a piston pin is the connecting rod 10 with an in 1 unrecognizable piston of the reciprocating internal combustion engine coupled articulated. The piston is received translationally displaceable in a combustion chamber in the form of a cylinder of the reciprocating internal combustion engine.

The reciprocating internal combustion engine also has a detail of 2 recognizable crankshaft 14 on. The crankshaft 14 is at an in 1 and 2 not shown crankcase of the reciprocating internal combustion engine rotatably mounted about an axis of rotation relative to the crankcase. For this purpose, the crankshaft 14 a plurality of shaft journals, of which in 2 two with 16 designated shaft journals are recognizable. In other words, the crankshaft 14 over the shaft journal 16 mounted on the crankcase.

The crankshaft 14 also has a plurality of crankpins, of which in 2 one with 18 designated crankpin is recognizable. In synopsis with 1 it can be seen that the connecting rod 10 about a whole with 20 designated eccentric rotatably on the crank pin 18 is stored. The eccentric bearing 20 includes an eccentric 22 , which related to the crankpin 18 is arranged eccentrically. Furthermore, the eccentric bearing comprises 20 a bearing element 24 , which in the radial direction between the eccentric 22 and the connecting rod 10 arranged and with respect to the crankpin 18 is concentric. The eccentric 22 is a bearing cup over which the connecting rod 10 on the crankpin 18 is stored or stored.

The piston is thus over the piston pin and the connecting rod 10 articulated with the crankshaft 14 connected, so that the translational movements of the piston in the cylinder in a rotational movement of the crankshaft 14 be converted around its axis of rotation relative to the crankcase.

The compression ratio of the cylinder is by causing a rotation of the eccentric 22 relative to the crankpin 18 and relative to the connecting rod 10 variable. In other words, the compression ratio of the cylinder can be changed or be varied by the eccentric 22 relative to the crankpin 18 and relative to the connecting rod 10 is twisted. This rotation results in a change in the stroke that the piston travels in its translatory movement in the cylinder. The compression ratio is also referred to as "epsilon" and abbreviated to ε.

In other words, by turning the eccentric 22 relative to the crankpin 18 and relative to the connecting rod 10 the so-called gauge of the connecting rod 10 be changed, so that thereby the reciprocating internal combustion engine with a first, low compression ratio and at least a second, high compression ratio can be operated. For example, the low compression ratio is 8.6, with the high compression ratio being 10.5, for example. Thus, the compression ratio can be adapted to at least two mutually different operating points of the reciprocating internal combustion engine, so that in particular in the partial load range an efficient and thus fuel consumption and CO ₂ emission-poor operation can be displayed. In particular, it is possible to increase the compression ratio after a switching operation in order to enable efficient operation, in particular in the partial load range with the second compression ratio. In contrast, in a higher load range, for example, at full load, then again the compression ratio can be reduced, for example, the low compression ratio is set.

To realize the change in the compression ratio is off 2 and 4 recognizable guide element 26 provided, which is fixed to the crankcase. In other words, the guide element 26 at least indirectly attached to the crankcase and immovable relative to the crankcase. The guide element 26 has a guideway 28 on, whereby at least a partial area 30 the guideway 28 in the direction of rotation of the crankshaft 14 rejuvenated.

Furthermore, one is on the crankshaft 14 arranged and thus with the crankshaft 14 co-rotating sliding piece in the form of a particularly good 3 recognizable bolt 32 intended. The bolt 32 is at a warehouse block 34 stored and relative to the bearing block 34 and relative to the crankshaft 14 in the axial direction of the crankshaft 14 displaceable. Out 2 it can be seen that the bearing block 34 by means of two screws 36 on the crankshaft 14 is attached.

The bolt 32 is a particularly good one 3 recognizable sliding block 38 on which - as in 3 represented by a double arrow - in the axial direction relative to the crankshaft 14 is displaceable. This shift is - like out 4 is shown by the double arrow visible there - by means of the guide element 26 effected.

The bolt 32 is namely by turning the crankshaft 14 in cooperation with the guide element 26 movable and due to the interaction in the axial direction relative to the crankshaft 14 from a first, in 5 recognizable position, in at least one of 7 recognizable, second position movable. In the second position is by means of the bolt 32 an operative connection between the eccentric 22 and the crankshaft 14 and a resulting rotation of the eccentric 22 relative to the crankpin 18 and relative to the connecting rod 10 effected or effected.

With a rotation of the crankshaft 14 the bolt comes 32 over the Kulissenstein 38 in cooperation with the guide element 26 , In other words, the backdrop stone 38 in the guideway 28 introduced, wherein the tapered portion 30 serves as an insertion aid. As a result, the bolt acts 32 over the Kulissenstein 38 positively with the guide element 26 together, leaving the bolt 32 by means of the guide element 26 in the axial direction relative to the crankshaft 14 is moved. As long as the bolt 32 with the guide element 26 interacts, there is an active clamping of the eccentric 22 between the bolt 32 and the crankshaft 14 ,

The eccentric 22 , which is an eccentric bearing shell or comprises at least two circumferentially adjacent bearing shells, is of the rotating crankshaft 14 entrained or entrained as a result of the active clamping, so that the eccentric 22 that is, for example, the bearing shells of the eccentric 22 , with respect to the oscillating connecting rod 10 to be twisted. This rotation or adjustment of the eccentric 22 relative to the connecting rod 10 and relative to the crankpin 18 takes place in the direction of rotation of the crankshaft, which in 6 and 8th is represented by a respective directional arrow.

Out 5 is a clamping of the eccentric 22 between a bunch 40 the crankshaft 14 and the bolt 32 recognizable. In this first position of the bolt 32 takes the eccentric 22 one out 8th recognizable position.

In the radial direction between the eccentric 22 and the connecting rod 10 is a designated as a whole with 42 freewheel, which is the rotation of the eccentric 22 relative to the crankpin 18 and relative to the connecting rod 10 in a first direction of rotation, namely in the direction of rotation of the crankshaft 14 , allows and blocks in a first direction of rotation opposite, second direction of rotation. These are on eccentric 22 hook 44 of the freewheel 42 arranged. On the bearing element 24 are Raststufen 47 provided with which the hooks 44 can cooperate positively. As a result of positive interaction of hooks 44 with the rest stops 47 becomes the rotation of the eccentric 22 prevented in the second direction of rotation. The bearing element 24 is for example at the connecting rod 10 fixed, that is relative to the connecting rod 10 immobile.

Out 8th is also an attack 46 recognizable, which on the bearing element 24 or at the connecting rod 10 is provided. Preferably, it is provided that the stop 46 and thus the bearing element 24 at the connecting rod 10 fixed and thus relative to the connecting rod 10 immovable. For example, it can be provided that the connecting rod 10 and the bearing element 24 are integrally formed with each other.

At the eccentric 22 is one with the stop 46 corresponding, further stop 48 intended.

In the first position of the bolt 32 takes the eccentric 22 one out 6 recognizable position. Out 7 is the second position of the bolt 32 recognizable. In the second position is a clamping between a collar 50 of the eccentric 22 and the warehouse block 34 formed, so that the eccentric 22 from the crankshaft 14 is taken. The Bund 50 engages in a corresponding recess of the bolt 32 one, leaving the eccentric 22 and the bolt 32 interact positively. This will cause the eccentric 22 at an axial displacement of the bolt 32 taken from this, so that the axial movement of the bolt 32 on the eccentric 22 can be transferred.

Because of the eccentric 22 from the crankshaft 14 is taken, is the eccentric 22 180 degrees relative to the crankpin 18 and relative to the connecting rod 10 twisted. The eccentric 22 will - like out 8th is recognizable - twisted until the stops 46 . 48 come in mutual support system. By means of the stops 46 . 48 Thus, the rotation of the eccentric 22 limited or stopped.

Overall, it can be seen that the necessary to adjust the compression ratio rotation of the eccentric 22 180 degrees due to an explosive axial displacement of the eccentric 22 on the crankpin 18 This is done via the bolt 32 is effected during the rotation of the crankshaft 14 in the acting as a cam guide element 26 retracts. By means of the guideway 28 becomes the bolt 32 over the Kulissenstein 38 and related to the image plane of 7 moved from the first position to the right to the second position. This locks the bolt 32 the eccentric 22 between its covenant 50 and the warehouse block 34 so that the eccentric 20 and thus the eccentric 22 with the speed of the crankshaft 14 entrained and relative to the connecting rod 10 twisted until the stop 48 with the at the connecting rod 10 provided stop 46 comes in support system.

After that, the bolt will 32 again something back, that is based on the image plane of 7 pushed to the left, so that the bolt 32 at speed of the crankshaft 14 around the covenant 50 of the eccentric camp 20 or of the bearing element 24 can turn or vice versa. Thus, for example, a defined adjustment of the eccentric bearing 20 respectively.

A further rotation of acting as a bearing shell eccentric 22 done by moving the bolt 32 for example, based on the image plane of 7 to the left. This will cause the eccentric 22 - as in 5 is shown - between the federal government 40 the crankshaft 14 and the bolt 32 clamped, causing the eccentric 22 entrained to a second stop. Then the bolt 32 moved back a bit, and the other compression ratio is set.

Out 9 is a lock of the bolt 32 recognizable in his two positions. These positions are thus respective stages of the bolt 32 , In other words, a two-stage adjustment is provided in the present case. Alternatively, however, it is also possible to provide a pulp or multistage adjustment.

To lock the bolt 32 is a spring 56 provided, which on the one hand to a ball 54 and on the other hand on the crankshaft 14 is supported. By means of the spring 56 becomes the ball 54 acted upon by a spring force and so in a respective recess 52 of the bolt 32 held. When moving the bolt 32 in the axial direction relative to the crankshaft 14 and thus relative to the ball 54 becomes the ball 54 from one of the recesses 52 moved out, resulting in a compression of the spring 56 accompanied. Is the bolt 32 moved from one position to the other position, so is the other of the recesses 52 in overlap with the ball 54 so that the spring 56 relax again and the ball 54 into the other of the recesses 52 can move in. This is the bolt 32 locked again.

LIST OF REFERENCE NUMBERS

10

pleuel

12

big connecting rod eye

14

crankshaft

16

shaft journal

18

crank pins

20

eccentric

22

eccentric

24

bearing element

26

guide element

28

guideway

30

subregion

32

bolt

34

bearing block

36

screw

38

sliding block

40

Federation

42

freewheel

44

hook

46

attack

47

click stops

48

attack

50

Federation

52

recess

54

Bullet

56

feather

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 10309651 A1 [0002]
• DE 19944668 A1 [0003]
• US 2011/0155106 A1 [0004]

Claims (4)

Reciprocating internal combustion engine for a motor vehicle, comprising a crankcase, with a crank housing rotatably mounted on the crankcase about an axis of rotation relative to the crankcase and at least one crank pin ( 18 ) having crankshaft ( 14 ) and at least one connecting rod assigned to a cylinder of the reciprocating internal combustion engine (US Pat. 10 ), which via an eccentric ( 22 ) on the crankpin ( 18 ) is mounted, wherein for changing the compression ratio of the cylinder, a rotation of the eccentric ( 22 ) relative to the crankpin ( 18 ) and to the connecting rod ( 10 ) is effected, characterized in that a fixed to the crankcase guide element ( 26 ) and one on the crankshaft ( 14 ) arranged sliding piece ( 32 ) are provided, which by turning the crankshaft ( 14 ) in cooperation with the guiding element ( 26 ) and due to the interaction in the axial direction relative to the crankshaft ( 14 ) is displaceable from a first position into at least one second position, in which by means of the sliding piece ( 32 ) an operative connection between the eccentric ( 22 ) and the crankshaft ( 14 ) and the resulting rotation of the eccentric ( 22 ) is feasible. Reciprocating internal combustion engine according to claim 1, characterized in that between the eccentric ( 22 ) and the connecting rod ( 10 ) a freewheel ( 42 ) is arranged, which the rotation of the eccentric ( 22 ) relative to the crankpin ( 18 ) and to the connecting rod ( 10 ) in a first direction of rotation and in one of the first direction of rotation opposite, second direction of rotation locks. Reciprocating internal combustion engine according to one of claims 1 or 2, characterized in that the guide element ( 26 ) a guideway ( 28 ) into which the sliding piece ( 32 ) engages positively in cooperation and by means of which the sliding piece ( 32 ) is displaceable due to the intervention. Reciprocating internal combustion engine according to claim 3, characterized in that at least a portion ( 30 ) of the guideway ( 28 ) in the direction of rotation of the crankshaft ( 14 ) rejuvenated.

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