EP3260692B1 - Combustion engine, in particular reciprocating piston combustion engine - Google Patents

Description

The invention relates to an internal combustion engine, in particular a reciprocating piston internal combustion engine, according to the preamble of claim 1, a cylinder liner set according to the preamble of claim 14 and a vehicle, in particular a utility vehicle, with the internal combustion engine according to claim 15.

Internal combustion engines, in particular reciprocating piston internal combustion engines, regularly have at least one cylinder which has a cylinder track as a guide for a piston assigned to the cylinder. In order to reduce the friction between a cylinder wall forming the cylinder race and the associated piston or the piston rings of the piston, it is known to provide the piston rings with a friction-reducing coating. The coating can be formed, for example, by a PVD layer (PVD: Physical Vapor Deposition) or PA-CVD layer (Plasma-Assisted Chemical Vapor Deposition), in particular by DLC layers (DLC: Diamond like Carbon Coating). By reducing the friction between the cylinder wall and the associated piston or the piston rings, the fuel consumption and the emissions of the internal combustion engine as well as the wear of the components rubbing against each other are significantly reduced.

Furthermore, it is also known to provide the cylinder wall forming the cylinder race, in particular on mixed friction areas of the cylinder race, with a friction-reducing coating in order to reduce the friction between the cylinder wall and the associated piston. Such a coating can be formed, for example, by a thermal spray layer or likewise by a DLC layer, in particular in connection with laser textures.

The coating of the cylinder liner or the cylinder wall forming the cylinder liner is often difficult, however, since the cylinder wall is regularly difficult to access, in particular due to the diameter / height ratio of the cylinder. The coating can therefore often not be applied with the desired coating quality.

From the GB 600 156 A A method for producing a wear-resistant cylinder for an internal combustion engine is known, in which a wear-resistant annular element is provided in an area of the cylinder close to the cylinder head.

The further one JP H11 311 501 A discloses a cylinder of an internal combustion engine in which a part of the cylinder liner is formed by an annular element.

From the JP S61 241 564 A an internal combustion engine is known in which a part of the cylinder track is formed by an annular element.

The further one DE 31 23 080 A1 discloses a reciprocating piston machine in which a liner inserted in a cylindrical recess is provided in the upper cylinder area, in which only the upper piston part is guided when the piston is provided with a compression and oil control ring at the top dead center.

The object of the invention is to provide an internal combustion engine, in particular a reciprocating piston internal combustion engine, in which the friction between the cylinder track and the associated piston or the piston rings of the piston is reduced in a simple manner in terms of production technology.

This object is achieved with the features of the independent claims. Preferred developments are disclosed in the subclaims.

According to claim 1, an internal combustion engine, in particular a reciprocating piston internal combustion engine, is proposed with at least one cylinder having a cylinder raceway, the cylinder raceway forming a guide for a piston assigned to the cylinder, the cylinder raceway only partially through a cylinder wall of a crankcase or at The cylinder liner is fixed to the crankcase, the cylinder liner being formed in a central region, viewed in the cylinder axial direction, by the cylinder wall on the crankcase side or cylinder liner side, the crankcase side or cylinder liner side cylinder wall on an upper region adjoining the central region and / or has a circumferential recess, in particular in the circumferential direction of the cylinder, on a lower region of the cylinder race that adjoins the central region and into which a one-piece s or multi-part annular sliding element is used, the radially inner sliding element wall of which forms part of the cylinder raceway.

In this way, the friction between the cylinder and the piston / piston rings can easily be reduced in terms of production technology, since the cylinder wall on the crankcase side or on the cylinder liner side no longer has to be provided with a friction-reducing coating on the upper and / or lower region of the cylinder track Reduce friction between the cylinder and the piston / piston rings. Instead, the sliding element with optimized sliding properties is now simply inserted into the recess of the cylinder wall on the crankcase side or on the cylinder liner side at the upper and / or the lower region, in particular at the upper and lower dead center, of the cylinder liner. The sliding properties of the respective sliding element can be optimized as desired in a technically particularly simple and efficient manner before it is inserted into the respective recess. For example, the sliding element can easily be provided with a friction-reducing surface coating before it is inserted into the recess. As a result, the process complexity and the costs are significantly reduced in comparison to a coating of the cylinder wall on the crankcase side or on the cylinder liner side.

In a preferred embodiment of the internal combustion engine according to the invention, the central region of the cylinder liner is arranged in such a way that a hydrodynamic sliding bearing is formed on it during operation of the internal combustion engine between the cylinder wall and the associated piston. Thus, low-loss fluid friction prevails in the central area of the cylinder liner.

The upper and / or the lower region of the cylinder track is further preferably arranged in such a way that mixed friction, in particular mixed friction and static friction, prevails between the respective sliding element and the associated piston during operation of the internal combustion engine. The friction between the cylinder race and the associated piston can be reduced particularly effectively by means of the respective sliding element. It is preferably provided that during the operation of the internal combustion engine, a coefficient of friction between the respective sliding element and the associated piston lies in a range from 0.01 to 0.06 at the upper and / or lower region of the cylinder barrel, in order to make the internal combustion engine particularly efficient to be able to operate.

The upper region of the cylinder race is preferably formed by an upper end region of the cylinder race. The lower region of the cylinder race is likewise preferably formed by a lower end region of the cylinder race.

The upper region of the cylinder track is further preferably arranged such that an outer sliding wall of the associated piston is in contact with the sliding element at least at the top dead center (TDC) of the piston. This can cause friction and wear on the cylinder barrel can be reduced in a particularly effective manner. It is preferably provided that the outer sliding wall of the piston is in contact with the sliding element at least in a crank angle range of the internal combustion engine from 10 ° crank angle before TDC to 15 ° crank angle after TDC. The term “piston” is to be understood here in a broad sense above and below and is intended to include not only the piston but also piston rings associated with the piston.

As an alternative and / or in addition, the lower region of the cylinder raceway can also be arranged such that an outer slide path of the associated piston is in contact with the sliding element at least at the bottom dead center (UT) of the piston. It is preferably provided that the outer sliding wall of the piston is in contact with the sliding element at least in a crank angle range of the internal combustion engine from 10 ° crank angle before UT to 15 ° crank angle after UT.

In a preferred specific embodiment, the length or height of the cylinder track is many times greater than the height of the annular sliding element. With such a height difference, the provision of the sliding elements according to the invention is particularly effective. The length or the height of the cylinder race is particularly preferably at least four times as large as the height of the annular sliding element.

The material of the respective sliding element and the material of the cylinder wall further preferably have an essentially identical coefficient of thermal expansion. This reliably prevents temperature-related edges or jumps from forming between the cylinder wall on the crankcase side or the cylinder liner side and the respective sliding element, so that there is always an essentially smooth transition between the cylinder wall and the respective sliding element. It is preferably provided that the material of the sliding element and the material of the cylinder wall are essentially identical. In a preferred specific embodiment, the material of the sliding element and the material of the cylinder wall are made of steel, cast iron or aluminum.

According to the invention, the annular sliding element is coated on the inside with a sliding layer in order to further reduce the friction and wear of the internal combustion engine. It is preferably provided that the sliding layer DLC layer and / or by APS layer (APS: atmospheric plasma spraying) is formed. The APS layer can, for example, be metallic, metal-ceramic or all-ceramic.

A support layer or stabilization layer is preferably provided between the sliding layer and a base material of the annular sliding element, in particular formed by aluminum. Such a support layer reliably counteracts the so-called eggshell effect, that is to say breaking of the layer by plastic deformation of the aluminum base material, for example. It is preferably provided that the support layer is formed by a chemical nickel layer.

More preferably, the radially inner sliding element wall of the respective sliding element has a lower surface roughness than a wall area of the cylinder wall on the crankcase side or on the cylinder liner side forming the cylinder track. This effectively reduces the friction and wear of the internal combustion engine and at the same time simplifies the manufacture of the internal combustion engine, since the cylinder wall of the crankcase or the cylinder liner, which is usually difficult to access, is provided with a lower surface roughness than the easy-to-process sliding elements.

The respective sliding element is preferably in a flat contact connection with the crankcase or the cylinder liner in order to be able to fasten the sliding element simply and reliably. The sliding element is further preferably connected to the crankcase or the cylinder liner in a positive and / or material connection, in particular by means of an adhesive connection or a welded connection, in order to reliably fasten the sliding element to the crankcase or the cylinder liner. The respective sliding element is preferably fixed on the crankcase or the cylinder liner by thermal joining or mechanical pressing.

In a preferred specific embodiment, the recess of the cylinder wall, seen in cross section, has an essentially U-shaped contour in order to make the recess simple and functionally optimized. Further preferably, the annular sliding element is essentially rectangular in cross section in order to make the annular sliding element simple in terms of production technology. More preferably, the sliding element is contour-matched in the associated recess.

To achieve the above-mentioned object, a cylinder liner set is furthermore claimed, with a cylinder liner forming a cylinder liner, the cylinder liner being only partially formed by a cylinder wall of the cylinder liner, the cylinder liner passing through a central region, viewed in the cylinder axial direction the cylinder wall of the cylinder liner is formed, the cylinder wall of the cylinder liner on an upper region adjoining the central region upwards and / or on a lower region of the cylinder liner adjoining the central region downwards, has a circumferential depression, in particular running in the circumferential direction of the cylinder, into each of which a one-part or multi-part annular sliding element as Part of the set can be used, wherein a radially inner sliding element wall of the sliding element used forms part of the cylinder track. According to the invention, the annular sliding element is coated on the inside with a sliding layer.

The advantages resulting from the cylinder liner set according to the invention are identical to the advantages of the internal combustion engine according to the invention that have already been recognized, so that they are not repeated here.

Furthermore, a vehicle, in particular a commercial vehicle, is also claimed with the internal combustion engine according to the invention. The advantages resulting from the vehicle according to the invention are also identical to the advantages of the internal combustion engine according to the invention that have already been recognized, so that they are not repeated here either.

The advantageous embodiments and / or further developments of the invention explained above and / or reproduced in the subclaims can be used individually and / or in any combination, apart from, for example, in the case of clear dependencies or incompatible alternatives.

The invention and its advantageous training and / or further developments as well as their advantages are explained in more detail below only with reference to drawings.

Figur 1

in einer Schnittdarstellung einen Teil einer ersten Ausführungsform einer erfindungsgemäßen Brennkraftmaschine;

Figur 2

das Detail A aus Figur 1 in vergrößerter Darstellung;

Figur 3

eine Schnittdarstellung entlang der Schnittebene B-B aus Figur 1;

Figur 4

in einer Darstellung gemäß Figur 3 eine zweite Ausführungsform der erfindungsgemäßen Brennkraftmaschine,

Figur 5

in einer Darstellung gemäß Figur 1 eine dritte Ausführungsform der erfindungsgemäßen Brennkraftmaschine; und

Figur 6

das Detail C aus Figur 5 in vergrößerter Darstellung.

Show it:

Figure 1

in a sectional view part of a first embodiment of an internal combustion engine according to the invention;

Figure 2

the detail A. Figure 1 in an enlarged view;

Figure 3

a sectional view taken along the section plane BB Figure 1 ;

Figure 4

in a representation according to Figure 3 a second embodiment of the internal combustion engine according to the invention,

Figure 5

in a representation according to Figure 1 a third embodiment of the internal combustion engine according to the invention; and

Figure 6

the detail C. Figure 5 in an enlarged view.

In Figure 1 part of an internal combustion engine 1 according to the invention is shown in a sectional view. The internal combustion engine 1 designed as a reciprocating piston internal combustion engine has a crankcase 3 and a cylinder liner 5 fixed to the crankcase 3. The cylinder liner 5 is fixed here by way of example on the crankcase 3 by means of a press connection.

The cylinder liner 5 has a cylinder wall 7 radially on the inside, which forms a cylinder of the internal combustion engine 1, in the cylinder space 9 of which a piston 11 of the internal combustion engine 1, indicated by dashed lines, is arranged. The cylinder wall 7 here forms a central region 13 of a cylinder raceway, viewed in the cylinder axial direction x, by means of which the piston 11 is guided.

The cylinder wall 7 here has a circumferential recess 17 in an upper region 15 of the cylinder race, as seen in the cylinder axial direction x and adjoining the central region 13 of the cylinder race, into which a ring-shaped sliding element 19, for example one-piece, is inserted. A radially inner sliding element wall 21 of the annular sliding element 19 likewise forms part of the cylinder race here.

According to Fig. 1 Here, the cylinder wall 7 also has a circumferential recess 23 in a lower region 22, as seen in the cylinder axial direction x and adjoining the central region 13, into which a ring-shaped sliding element 25 is also inserted, by way of example. A radially inner sliding element wall 27 of the sliding element 25 also forms part of the cylinder race here. The sliding elements 19, 25 can be fixed on the cylinder liner 5, for example, by thermal joining or mechanical pressing. In addition, the sliding elements 19, 25 are, for example, essentially identical or structurally identical.

Furthermore, the crankcase 3, the cylinder liner 5 are made of cast iron (GJL) and the sliding elements 19, 25 are made of steel here. In addition, the cylinder liner 5 and the sliding elements 19, 25 form a cylinder liner set here.

Furthermore, the upper region 15 of the cylinder raceway or the upper sliding element 19 here, for example, forms an upper end region of the cylinder raceway. In addition, the lower region 22 or the lower sliding element 25 of the cylinder race also forms a lower end region of the cylinder race here, for example. Thus, the cylinder track extends essentially from an upper side 29 of the upper slide element 19 over a cylinder track length I _ZLB to an underside 31 of the lower slide element 25. A height h _{G of} the respective slide element 19, 25 is, for example, many times greater than the length or the height of the cylinder _liner I _ZLB .

Furthermore, the upper region 15 of the cylinder liner or the sliding element 19 is also arranged here in such a way that an outer sliding wall of the piston 11 is in contact or in contact with the sliding element 19 at least at the top dead center (TDC) of the piston 11. In addition, the lower region 22 of the cylinder raceway or the sliding element 25 is also arranged here in such a way that the outer sliding wall of the piston 11 is in contact or in contact with the sliding element 25 at the bottom dead center (UT) of the piston 11.

How from Figure 1 further emerges, the cylinder wall 7 of the cylinder liner 5 continues here above the recess 17 with a wall region 33 upwards. In addition, the cylinder wall 7 continues here below the recess 23 with a wall region 35 downwards. The wall regions 33, 35 and a wall region 37 of the cylinder wall 7 located between the depressions 17, 23 have an identical diameter here by way of example. In the recesses 17, 23 of the cylinder wall 7 or in the wall regions 39, 41 of the cylinder wall 7 forming the recesses 17, 23, the diameter of the cylinder wall 7 is enlarged in comparison to the wall regions 33, 35, 37.

Furthermore, the central region 13 of the cylinder liner or the wall region 37 of the cylinder wall 7 is arranged here in such a way that a hydrodynamic plain bearing is essentially formed between the wall region 37 of the cylinder wall 7 and the piston 11 during operation of the internal combustion engine 1. In addition, the upper region 15 and the lower region 22 of the cylinder raceway or the depressions 17, 23 of the cylinder wall 7 are arranged such that mixed friction prevails between the sliding elements 19, 25 and the piston 11 during operation of the internal combustion engine 1. Thus, the sliding elements 29, 25 are arranged here on those areas of the cylinder raceway at which friction occurs during operation of the internal combustion engine 1 and therefore a relatively high energy loss.

How further out Fig. 2 shows, the respective recess 17, 23 or the respective wall area 39, 41 of the cylinder wall 7 here, viewed in cross section, has an essentially U-shaped contour. In addition, the respective sliding element 19, 25 is here according to Fig. 2 rectangular in cross section. Furthermore, the respective sliding element 19, 25 is here, for example, adapted to the contour in the respectively assigned recess 17, 23, so that the respective sliding element 19, 25, with the exception of the respective radially inner sliding element wall 21, 27, is in contact with the respective wall area 39, 41 of the cylinder wall 7 is. Thus, the sliding elements 19, 25 are here also connected to the cylinder liner 5 in a flat contact connection and positively connected to the cylinder liner.

How from Fig. 2 Furthermore, the respective sliding element 19, 25 is also coated on the inside or radially inside with a sliding layer 43, by means of which the friction between the sliding elements 19, 25 and the piston 11 is reduced. This sliding layer 43 is preferably formed by a DLC layer or by an APS layer. The sliding layer 43 is applied here directly to the base body 45 of the respective sliding element 19, 25 formed here by way of example by steel. Furthermore, the radially inner sliding element wall 21, 27 of the respective sliding element 19, 25 also has, for example, a lower surface roughness than the wall region 37 of the cylinder wall 7.

As further in Fig. 3 is shown, the respective sliding element 19, 25 is here also formed in one piece or by a ring closed in the circumferential direction.

In Fig. 4 A second embodiment of the internal combustion engine 1 according to the invention is shown. Compared to that in Figure 3 shown first embodiment of the internal combustion engine 1, the respective sliding element 19, 25 is not formed here in one part, but in several parts. The respective sliding element 19, 25 is composed here of several, here three examples of ring segments 49. The ring segments 49 are essentially identical or identical in construction.

In Fig. 5 A third embodiment of the internal combustion engine 1 is shown. Compared to that in Figure 1 The first embodiment shown does not have the cylinder liner 5 here. Instead, the cylinder wall 7 forming the cylinder is formed here by the crankcase 3 itself. Furthermore, the crankcase 3 and the sliding elements 19, 25 are not made of steel, but of aluminum.

How further out Fig. 6 a supporting layer 51 is provided between the sliding layer 43 and the base body 45 of the respective sliding element 19, 25 formed here by aluminum, by means of which the stability of the sliding layer 43 is increased or the eggshell effect of the sliding layer 43 is counteracted.

LIST OF REFERENCE NUMBERS

1

Internal combustion engine

3

crankcase

5

Cylinder liner

7

cylinder wall

9

cylinder space

11

piston

13

central area

15

upper area

17

deepening

19

Slide

21

Slide wall

22

lower area

23

deepening

25

Slide

27

Slide wall

29

top

31

bottom

33

Area

35

Area

37

Area

39

wall area

41

wall area

43

Overlay

45

body

49

ring segment

51

backing

I _ZLB

Cylinder path length

Claims (15)

1. An internal combustion engine, especially a reciprocating internal combustion engine, with at least one cylinder having a cylinder barrel, wherein the cylinder barrel forms a guide for a piston (11) which is associated with the cylinder,
   wherein the cylinder barrel is only partially formed by a cylinder wall (7) of a crankcase (3) or of a cylinder liner (5) which is fastened to the crankcase (3), wherein the cylinder barrel, in a central region (13) as seen in the cylinder axial direction (x), is formed by the cylinder wall (7),
   wherein the cylinder wall (7), in an upper region (15) of the cylinder barrel adjoining the central region (13) towards the top and/or in a lower region (22) of the cylinder barrel adjoining the central region (13) towards the bottom, has an encompassing recess (17, 23), especially extending in a circumferential direction of the cylinder, into which is inserted in each case a one-piece or multi-piece annular sliding element (19, 25), the radially inner wall (21, 37) of which forms a part of the cylinder barrel,
   characterized in that
   the annular sliding element (19, 25) is coated on the inner side with a slide coating (43).
2. The internal combustion engine according to Claim 1, characterized in that the central region (13) of the cylinder barrel is arranged in such a way that in essence a hydrodynamic sliding bearing is formed in this region between the cylinder wall (7) and the associated piston (11) during operation of the internal combustion engine (1).
3. The internal combustion engine according to Claim 1 or 2, characterized in that the upper and/or lower region (15, 22) of the cylinder barrel are/is arranged in such a way that mixed friction between the respective sliding element (19, 25) and the associated piston (11) prevails in these/this region(s) during operation of the internal combustion engine (1), wherein it is preferably provided that a friction coefficient between the respective sliding element (19, 25) and the associated piston (11) lies within a range of between 0.01 and 0.06 in the upper and/or lower region (15, 22) of the cylinder barrel during operation of the internal combustion engine (1).
4. The internal combustion engine according to one of the preceding claims, characterized in that the upper region (15) of the cylinder barrel forms an upper end region of the cylinder barrel, and/or in that the lower region (22) of the cylinder barrel forms a lower end region of the cylinder barrel.
5. The internal combustion engine according to one of the preceding claims, characterized in that the upper region (15) of the cylinder barrel is arranged in such a way that an outer slide wall of the associated piston (11) is in contact with the sliding element (19) at least at the top dead centre point (TDC) of the piston (11), wherein it is preferably provided that the outer slide wall of the piston (11) is in contact with the sliding element (19) at least within a crank angle range of the internal combustion engine of between 10° crank angle before TDC and 15° crank angle after TDC.
6. The internal combustion engine according to one of the preceding claims, characterized in that the lower region (22) of the cylinder barrel is arranged in such a way that an outer slide wall of the associated piston (11) is in contact with the sliding element (25) at least at the bottom dead centre point (BDC) of the piston (11), wherein it is preferably provided that the outer slide wall of the piston (11) is in contact with the sliding element (25) at least within a crank angle range of the internal combustion engine (1) of between 10° crank angle before BDC and 15° crank angle after BDC.
7. The internal combustion engine according to one of the preceding claims, characterized in that the length (I_ZLB) of the cylinder barrel is larger by a multiple, preferably at least four times larger, than the height of the annular sliding element (19, 25).
8. The internal combustion engine according to one of the preceding claims, characterized in that the material of the sliding element (19, 25) and the material of the cylinder wall (7) have a basically equal coefficient of thermal expansion, wherein it is preferably provided that the material of the sliding element (19, 25) and the material of the cylinder wall (7) are of basically identical design and/or are produced from steel, from cast iron or from aluminium.
9. The internal combustion engine according to one of the preceding claims, characterized in that the slide coating (43) is formed by a DLC coating and/or by an APS coating.
10. The internal combustion engine according to Claim 9, characterized in that a support layer (51) is provided between the slide coating (43) and a base material - especially formed by aluminium - of the annular sliding element (19, 25), wherein it is preferably provided that the support layer (51) is formed by a chemical nickel coating.
11. The internal combustion engine according to one of the preceding claims, characterized in that the radially inner wall (21, 27) of the respective sliding element (19, 25) has a lower surface roughness than a wall region (37) of the crankcase-side or cylinder liner-side cylinder wall (7) which forms the cylinder barrel.
12. The internal combustion engine according to one of the preceding claims, characterized in that the sliding element (19, 25) is in flat abutment contact with the crankcase (3) or the cylinder liner (5), and/or in that the sliding element (19, 25) is connected in a materially bonding manner to the crankcase (3) or to the cylinder liner (5).
13. The internal combustion engine according to one of the preceding claims, characterized in that the recess (17, 23) of the cylinder wall (7) has a basically U-shaped contour, as seen in cross section, and/or in that the annular sliding element (19, 25) is of rectangular design in cross section, and/or in that the sliding element (19, 25) lies in the associated recess (17, 23) in a contour-matched manner.
14. A cylinder liner set for an internal combustion engine according to one of the preceding claims, with a cylinder liner (3) forming a cylinder barrel,
    wherein the cylinder barrel is only partially formed by a cylinder wall (7) of the cylinder liner (5), wherein the cylinder barrel, in a central region (19) as seen in the cylinder axial direction, is formed by the cylinder wall (7) of the cylinder liner (5),
    wherein the cylinder wall (7) of the cylinder liner (5), in an upper region (15) of the cylinder barrel adjoining the central region (13) towards the top and/or in a lower region (22) of the cylinder barrel adjoining the central region (13) towards the bottom, has an encompassing recess (17, 23), especially extending in the cylinder circumferential direction, into which can be inserted in each case a one-piece or multi-piece annular sliding element (19, 25) of the set,
    wherein a radially inner wall (21, 27) of the inserted sliding element (19, 25) forms a part of the cylinder barrel,
    characterized in that
    the annular sliding element (19, 25) is coated on the inner side with a slide coating (43).
15. A vehicle, especially a commercial vehicle, having an internal combustion engine according to one of Claims 1 to 13.

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