DE102014005979A1 - Reciprocating internal combustion engine with at least one variably adjustable compression ratio - Google Patents

Abstract

The invention relates to a reciprocating piston internal combustion engine with at least one variably adjustable compression ratio, with a crankshaft (10) and with at least one lever element (18), which has a lateral surface (22) of the lever element (18) extending from an inner peripheral side and parallel to the axial direction. limited bearing receptacle (20) via which the lever element (18) on a bearing receiving (20) penetrating crankpin (12) of the crankshaft (10) is rotatably mounted, wherein the lever element (18) at least two in the axial direction of the crankshaft (10 ) has mutually opposite and spaced-apart tabs (26, 28) which respective, arranged in mutual overlap further bearing receptacles (34, 36) for supporting a bolt, via which a connecting rod of the reciprocating internal combustion engine articulated with the lever element (18) connectable is, characterized in that the axial extent (a1) of the inn Enumfangsseitigen lateral surface (22) is less than an axial distance (a2) between respective, in the axial direction facing away from each other outer sides (36, 38) of the tabs (26, 28).

Description

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

Such a reciprocating internal combustion engine with at least one variably adjustable compression ratio is for example the EP 1 835 146 B1 as well as the DE 10 2012 020 027 A1 to be known as known. The reciprocating internal combustion engine comprises a crankshaft and at least one lever element, via which the compression ratio can be set variably. The lever element has a bearing receptacle, via which the lever element is mounted on a crank pin of the crankshaft. The bearing receptacle is designed as a passage opening, wherein the crank pin penetrates the bearing receptacle. The bearing receptacle is delimited by an inner circumferential side surface of the lever element, wherein the inner peripheral side surface extends parallel to the axial direction of the crankshaft. The inner peripheral side surface of the lever member is arranged, for example, concentric with an outer peripheral side surface of the crank pin, so that the lever element is mounted particularly advantageous on the crank pin. The inner peripheral side surface and the outer peripheral side surface have, for example, the shape of a right circular cylinder.

The lever element further comprises at least two in the axial direction of the crankshaft opposite and spaced apart tabs. The tabs in turn have respective, arranged in at least partially mutual overlap bearing mounts for supporting a bolt. About the bolt a connecting rod of the reciprocating internal combustion engine is pivotally connected to the lever member or connected in the finished state of the reciprocating piston internal combustion engine.

This means that the lever element is rotatably mounted on the crank pin at a first bearing point. At a second bearing point of the connecting rod via the bolt is pivotally connected to the lever element or connected. The second bearing point is spaced apart in the radial direction of the crankshaft from the first bearing point. In addition, it can be provided that the lever element at a third bearing point is at least indirectly connectable to an actuating shaft of the reciprocating internal combustion engine. The third bearing point is spaced in the radial direction of the crankshaft from the first bearing, it being possible to provide that the first bearing point is arranged between the second bearing point and the third bearing point.

If, for example, the actuating shaft is rotated, this causes a rotation of the lever element about the crank pin relative thereto. This results in a translational displacement of a piston, which is articulated connected or connected via the connecting rod with the lever element. The piston is arranged in a combustion chamber in the form of a cylinder of the reciprocating internal combustion engine. By caused by the rotation of the actuating shaft rotating the lever member to the crank pin, the piston is displaced in the cylinder, whereby the compression ratio of the cylinder can be adjusted as needed and variable.

Object of the present invention is to develop a reciprocating internal combustion engine of the type mentioned in such a way that an improved storage of the lever element can be realized on the crank pin of the crankshaft.

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 comparison with the prior art improved storage of the lever element can be realized on the crank pin, it is inventively provided that the axial extent of the inner peripheral side surface is less than an axial distance between respective, in the axial direction facing away from each other outer sides of the tabs. As a result, the lever element in the region of its bearing on the crankpin is clearly opposite the tabs on which the bolt of the connecting rod is to be stored, graduated, whereby a particularly advantageous flow of force can be represented.

The invention is based on the finding that, in the case of a conventional lever element, which is not graded, an unfavorable force flow occurs, which causes an undesired and, for example, at least substantially concave deformation of the bearing receptacle. Conventional lever elements are not stepped and therefore formed continuously from the tabs to the inner peripheral side surface, so that usually the axial extent of the inner peripheral side surface and the axial distance between the respective outer sides of the tabs are the same. As a result of the gradation according to the invention, however, the lever element in the reciprocating internal combustion engine according to the invention is essential in the field of bearing support narrower or shorter than in the area of the tabs. In this way, in comparison to a continuous lever element and a reduction in friction and weight reduction of the reciprocating internal combustion engine can be realized because, for example, the crank pin with respect to its diameter as small as possible and can be formed as large as necessary. In addition, a sufficient lubrication between the lever member and the crank pin can be realized even with a small amount of lubricant. The lubricant is, for example, oil.

Due to the stepped configuration of the lever element, in particular the mass of the lever element can be kept low while realizing a particularly high strength of the crankshaft. As a result, the diameter of the crank pin can be made particularly small. In addition, a particularly cost-effective material for the crankshaft can be used, so that the cost of the reciprocating internal combustion engine can be kept very low overall.

In addition, the previously described, unfavorable power flow and the resulting unfavorable deformation of the bearing receptacle can be avoided or at least kept particularly low, since a particularly advantageous introduction of force into the connecting rod can be realized. This can form an advantageous and sustainable lubricant film for lubrication. In addition, a particularly advantageous supply of lubricant can be realized by respective bearings, on which the bolt is mounted on the tabs, between the lever element and the connecting rod.

In particular, it is possible to design the bearing of the lever element to the crankpin, that is, to the crankshaft, particularly narrow and thus narrow compared to the prior art. In addition, it is possible to realize a particularly large radius between the crank pin and at least one subsequent to the crank pin in the axial direction of the crankshaft, wherein the crank pin passes over this radius in the crank arm. By such, compared to the prior art significantly enlarged radius between the crank pin and the crank arm, a particularly high strength of the crankshaft can be represented.

The mentioned gradation of the lever element can for example be designed so that it has at least one simple chamfer. In other words, for example, a transition region is provided between the inner peripheral side lateral surface and at least one of the straps. The transition region may extend at least partially obliquely to the axial direction. In this case, it is provided, for example, that the extent of the transitional region extending obliquely to the axial direction is formed by a chamfer arranged in the transition region. Alternatively or additionally, it may be provided that the gradation is designed such that it optimizes the strength by virtue of which it is pulled around the inner radius of the straps at least substantially at a constant distance.

A further embodiment is characterized in that in the transition region at least one passage opening for lubricant, in particular oil, the reciprocating internal combustion engine is provided. The passage opening may be formed for example by a bore. The passage opening can be traversed by lubricant, so that the lubricant can be selectively guided by means of the passage opening. For example, it is possible to lubricants, which emerges on the bearing of the lever member on the crank pin, to guide the tabs and thus to the connecting rod. In this case, it is provided, for example, that the passage opening opens in a region between the tabs. As a result, the lubricant can be guided into this area between the tabs.

A further embodiment is characterized in that at least one collecting bag is provided for collecting the lubricant in the transition region. The catch bag is formed for example by an undercut of gradation. By means of the catching bag, for example, lubricant that leaks from the bearing of the lever element on the crankpin can be collected. The opening, for example, at one end into the area between the tabs, on the other hand, opens into the catching pocket, so that the collected lubricant can be guided by the passage opening from the catching pocket between the tabs and thus to the connecting rod. As a result, a sufficient supply of the connecting rod with lubricant can be ensured in a simple as well as weight and cost effective manner.

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

1 and 2 serve to explain the background of the invention.

The drawing shows in:

1 a schematic longitudinal sectional view of a crank pin and a crank pin mounted on the lever element of a reciprocating internal combustion engine with at least one variably adjustable compression ratio, wherein an undeformierter state of the lever member is shown;

2 a fragmentary sectional view of another of the crank pin and the lever member, which is shown in a deformed state;

3 a sectional view of a schematic sectional view of a crank pin and a bearing on the crank pin lever element of a reciprocating internal combustion engine with at least one variably adjustable compression ratio, wherein an axial extent of an inner circumferential side surface of the lever member is less than an axial distance between respective, in the axial direction opposite outer sides of tabs the lever element; and

4 a further schematic sectional view of the crank pin and the lever member according to 3 in an alternative embodiment.

In the figures, identical or functionally identical elements are provided with the same reference numerals.

1 and 2 show in a schematic longitudinal sectional view of a detail with a whole 10 designated crankshaft of a reciprocating internal combustion engine. The reciprocating internal combustion engine is used for example for driving a motor vehicle, in particular a passenger car. The crankshaft points in 1 unrecognizable shaft journal on which the crankshaft 10 is rotatably mounted on a crankcase of the reciprocating internal combustion engine about an axis of rotation relative to the crankcase. In addition, the crankshaft points 10 at least one crankpin 12 on. In the axial direction close on both sides respective crank webs 14 at the crankpin 12 at. The crankpin 12 has an outer peripheral side surface 16 on which is parallel to the axial direction of the crankshaft 10 extends and is formed at least substantially in the form of a right circular cylinder.

In addition, the reciprocating internal combustion engine has at least one combustion chamber in the form of a cylinder. In the cylinder, a piston is received translationally movable. The piston is connected via a bolt articulated to a connecting rod. As will be explained in more detail below, the in 1 connecting rod, not shown, which is also referred to as "Hauptpleuel", via a lever element in the form of a transverse lever 18 the reciprocating internal combustion engine hinged to the crank pin 12 coupled.

The cross lever 18 is on the crankpin 12 rotatably mounted. This means that the cross lever 18 relative to the crankpin 12 is rotatable. The cross lever 18 has an extension, which at least substantially transversely, that is perpendicular to the axis of rotation of the crankshaft 10 runs.

The cross lever 18 has a trained as a passage opening first bearing receptacle 20 on which in the radial direction of the crankshaft 10 to the outside through an inner peripheral side surface 22 of the cross lever 18 is limited. This inner peripheral side surface 22 extends parallel to the axis of rotation and thus parallel to the axial direction of the crankshaft 10 and is also formed at least substantially in the form of a right circular cylinder.

Out 1 is recognizable that the cross lever 18 over the first bearing receiver 20 on the crankpin 12 is rotatably mounted, wherein the crank pin 12 the camp admission 20 penetrates. Overall, it can be seen that the cross lever 18 at a first depository 24 on the crankpin 12 is stored.

The cross lever 18 is about at least one bearing element 25 on the crankpin 12 stored. The bearing element 25 is in the radial direction between the lateral surfaces 16 . 22 arranged, with the cross lever 18 in the radial direction through the intermediary of the bearing element 25 on the crankpin 12 is supported. At the bearing element 25 it is, for example, a sliding bearing element, in particular a bearing shell or a plain bearing shell.

Here are the lateral surfaces 16 . 22 arranged concentrically with each other. Furthermore, the inner peripheral side circumferential surface surrounds 22 the outer peripheral side surface 16 in the axial direction at least partially and in the circumferential direction of the crank pin 12 Completely.

The cross lever 18 has two tabs 26 . 28 on. The tabs 26 . 28 are in the axial direction of the crankshaft 10 arranged opposite each other and spaced from each other. This is in the axial direction between the tabs 26 . 28 an area 30 provided, which in the axial direction of the tabs 26 . 28 is limited. The tabs 26 . 28 are over a jetty 33 of the cross lever 18 connected together, with the tabs 26 . 28 integral with the bridge 33 are formed.

The tabs 26 . 28 each have a second bearing receptacle 32 . 34 on. The respective second bearing mounts 32 . 34 are also formed as through holes. This means that the trained as a passage opening, second bearing receptacle 32 the tab 26 completely penetrates, wherein the passage formed as a second bearing receptacle 34 the tab 28 completely penetrates. The bearing shots 32 . 34 are arranged in mutual overlap, so that is the bearing support 34 in the axial direction with the bearing receiver 32 is aligned or vice versa.

The bearing shots 32 . 34 serve to store an in 1 not shown further bolt, via which the aforementioned connecting rod is pivotally connected to the transverse lever. The other bolt for coupling the connecting rod with the cross lever 18 becomes, for example, in the axial direction of the crankshaft 10 through one of the second bearing receptacles 32 . 34 inserted through and at least partially into the other of the bearing receptacles 32 . 34 plugged in. As a result, the other bolt on the cross lever 18 stored twice.

The tab 26 has one of the tabs 28 in the axial direction facing away from outside 36 on. The tab 28 has a in the axial direction of the tab 26 opposite outside 38 on. Out 1 is recognizable that the respective outer sides 36 . 38 are remote from each other in the axial direction.

According to 1 is the cross lever 18 designed as a continuous or continuous transverse lever in the radial direction. This means that the cross lever 18 is not stepped, so that an axial extent a1 of the inner circumferential side surface 22 and an axial distance a2 between the outsides 36 . 38 are the same.

The cross lever 18 is, for example, indirectly with an in 1 not shown adjusting shaft articulated coupled. If the actuating shaft is rotated about an axis of rotation, this will result in a rotation of the transverse lever 18 relative to the crankpin 12 causes. Due to the described articulated coupling of the cross lever 18 with the connecting rod results from this rotation of the cross lever 18 relative to the crankpin 12 a translational displacement of the piston in the cylinder, so that thereby a compression ratio of the cylinder and thus the reciprocating internal combustion engine can be variably adjusted.

The distance a2 is provided, for example, to ensure a sufficiently stable and robust mounting of the further bolt on the transverse lever 18 to realize. However, the axial extent a1 corresponding to the distance a2 is relative to the bearing point 24 Acting loads actually oversized. In other words, the axial extent a1 could also be less than the distance a2 under strength aspects.

1 shows the cross lever 18 in an undeformed state. 2 shows the cross lever 18 in a deformed state. To this deformation of the cross lever 18 it comes, for example, during operation of the reciprocating internal combustion engine. In the 2 illustrated deformation results from an only unfavorable power flow, which leads to a disadvantageous concave deformation of acting as a crankshaft bearing bearing receptacle 20 leads.

Based on 3 and 4 are embodiments of the cross lever 18 illustrates where the in 2 illustrated deformation of the cross lever 18 avoided or at least kept low.

The basis of 3 and 4 illustrated embodiments of the cross lever 18 is common that the axial extent a1 of the inner peripheral side surface 22 is substantially less than the axial distance a2. In other words, the cross lever 18 from the tabs acting as bolt bearings 26 . 28 to crankshaft bearing (bearing support 20 ) formed clearly graduated. As a result, an advantageous power flow can be realized, so that undesirable deformations of the transverse lever 18 can be kept low at least.

Out 1 and 2 it can be seen that the crankpin 12 and in particular, the outer peripheral side surface 16 on both sides via a respective radius R in the respective crank arm 14 passes. The radius R is therefore a so-called transition radius. According to 1 and 2 the respective radius R is relatively small. In synopsis with 3 and 4 it can be seen that the stepped design of the transverse lever 18 one opposite 1 and 2 allows much larger design of the radius R.

This can cause tension in the crankshaft 10 be kept particularly low, so that the crankpin 12 can be configured with only a very small diameter. In addition, the crankshaft 10 be made of a particularly inexpensive material. This can be the weight, the cost and the space requirement of the reciprocating internal combustion engine can be kept low overall.

Out 3 and 4 it can be seen that between the inner peripheral side surface 22 and for example the tab 26 and / or the tab 28 , in particular of the respective, at least substantially perpendicular to the axis of rotation extending outside 36 and or 38 , a transition area 40 is provided. In 3 is based on the image plane of 3 left tab 26 a possible first embodiment of the transition region 40 and thus the cross lever 18 illustrated. On the right tab 28 is a second embodiment of the transition region 40 and thus the cross lever 18 illustrated. The left transition area 40 extends obliquely to the axial direction of the crankshaft 10 , This is in the transition area 40 on the left side a chamfer 42 intended. In other words, in the first embodiment, said gradation is a chamfer 42 educated. In the case of the right tab 28 illustrated second embodiment, the gradation is designed with a constant wall thickness around the inner radius, with different shapes are conceivable.

In addition, in each transitional area 40 a passage opening 44 arranged, which of lubricant, in particular oil, the reciprocating internal combustion engine can be flowed through. The respective passage opening 44 on the one hand leads into the area 30 between the tabs 26 . 28 , On the other hand, the respective passage opening opens 44 in the area of the radius R. This allows out of the bearing 24 escaping lubricant through the passage opening 44 from the depository 24 between the tabs 26 . 28 and thus led to the pin bearings.

In 4 is a third embodiment of the transition region 40 and thus the cross lever 18 illustrated. In the respective transition area 40 is a catch bag 46 provided for collecting the lubricant. The catch bag 46 is designed as an undercut. The catch bag 46 runs for example in the circumferential direction of the crank pin 12 around this completely and can be designed for example as a gutter. The passage opening opens 44 in the catch bag 46 , This may cause lubricant that gets in the catch bag 46 collects or is collected by means of this, over the respective passage opening 44 in the area 30 be guided.

LIST OF REFERENCE NUMBERS

10

crankshaft

12

crank pins

14

crank web

16

outer peripheral side surface

18

transverse lever

20

bearing seat

22

Inner peripheral side surface

24

depository

25

bearing element

26

flap

28

flap

30

Area

32

second bearing receiver

33

web

34

second bearing receiver

36

outside

38

outside

40

Transition area

42

chamfer

44

Through opening

46

collecting pocket

a1

axial extent

a2

axial distance

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

• EP 1835146 B1 [0002]
• DE 102012020027 A1 [0002]

Claims (7)

Reciprocating internal combustion engine with at least one variably adjustable compression ratio, with a crankshaft ( 10 ) and with at least one lever element ( 18 ), which has a circumferential surface extending from an inner peripheral side and parallel to the axial direction ( 22 ) of the lever element ( 18 ) limited stock intake ( 20 ), via which the lever element ( 18 ) at one the bearing admission ( 20 ) penetrating crankpin ( 12 ) of the crankshaft ( 10 ) is rotatably mounted, wherein the lever element ( 18 ) At least two in the axial direction of the crankshaft ( 10 ) opposing and spaced apart tabs ( 26 . 28 ), which respective, arranged in mutual overlap further bearing receptacles ( 34 . 36 ) for supporting a bolt, via which a connecting rod of the reciprocating internal combustion engine articulated to the lever element ( 18 ) is connectable, characterized in that the axial extent (a1) of the inner peripheral side surface ( 22 ) is smaller than an axial distance (a2) between respective outer sides facing away from one another in the axial direction ( 36 . 38 ) of the tabs ( 26 . 28 ). Reciprocating internal combustion engine according to claim 1, characterized in that between the inner peripheral side surface ( 22 ) and at least one of the tabs ( 26 . 28 ) a transition area ( 40 ) is provided. Reciprocating internal combustion engine according to claim 2, characterized in that the transition region ( 40 ) extends at least partially obliquely to the axial direction. Reciprocating internal combustion engine according to claim 3, characterized in that in the transition region ( 40 ) a chamfer ( 42 ) is provided. Reciprocating internal combustion engine according to one of claims 2 to 4, characterized in that in the transition region ( 40 ) at least one passage opening ( 44 ) is provided for lubricant of the reciprocating internal combustion engine. Reciprocating internal combustion engine according to claim 5, characterized in that the passage opening ( 44 ) into an area ( 30 ) between the tabs ( 26 . 28 ) opens. Reciprocating internal combustion engine according to one of claims 2 to 6, characterized in that in the transition region ( 40 ) at least one catch bag ( 46 ) is provided for collecting lubricant.

Images