DE102016208329B4 - Control system and check valve for placement in such a control system - Google Patents

Abstract

Control system for actuating two interacting with an adjusting actuator piston (14 and 15) for a device for changing the compression ratio of a cylinder unit of a reciprocating internal combustion engine, wherein the adjusting element (7) in a connecting rod eye (6) of a connecting rod (1) and arranged by the engine forces of the reciprocating internal combustion engine is adjustable in two different positions, in which in the support cylinders (19 and 20) guided single-acting actuator piston (14 and 15), which together with the support cylinders (19 and 20) each form a pressure chamber (21, 22), in a retracted or extended position, wherein the pressure chambers (21 and 22) on the one hand via an oil line (24, 25), in which a check valve (31, 32) is arranged, and a connecting rod bearing (23) with an oil gallery and on the other one between the check valve (31, 32) and the pressure chamber (21, 22) of the oil line (24, 25) abz oil return line (51, 52) are connected to a switching device, so that via the switching either one of the two oil lines (24, 25) is pressure relieved, each of the two oil return line (51, 52) is associated with a first aperture (47) and wherein the first orifice (47) is integrated into the respective non-return valve (31, 32), characterized in that the first orifice (47) has an orifice bore (49) radially penetrating a cylindrically shaped check valve housing (42) and into the oil return line (52) opens.

Description

Field of the invention

The invention relates to a control system for actuating two interacting with an adjusting actuator piston for a device for changing the compression ratio of a cylinder unit of a reciprocating internal combustion engine, wherein the adjusting element is arranged in a connecting rod of a connecting rod and adjustable by the engine forces of the reciprocating internal combustion engine in two different positions, in which guided in support cylinders single-acting actuator piston, which together with the support cylinders each form a pressure chamber, are in a retracted or extended position, the pressure chambers on the one hand via an oil line in which a check valve is arranged, and a connecting rod bearing with an oil gallery and Others are connected via a switch between the check valve and the pressure chamber from the oil line oil return line with a switching device, so that the Umschaltei direction either one of the two oil lines is pressure relieved.

Furthermore, the invention also relates to a control system for actuating two interacting with an adjusting actuator piston for a device for changing the compression ratio of a cylinder unit of a reciprocating internal combustion engine, wherein the adjusting element is arranged in a connecting rod eye of a connecting rod and adjustable by the engine forces of the reciprocating internal combustion engine in two different positions, in which the guided in support cylinders single-acting actuator pistons, which together with the support cylinders each form a pressure chamber, are in a retracted or extended position, the pressure chambers on the one hand via an oil line, in which a check valve is arranged, and a connecting rod bearing with a Oil gallery and on the other hand connected via a between the check valve and the pressure chamber of the oil line branching oil return line with a switching device, so that ü On the switching device selectively one of the two oil lines is pressure relieved, wherein each of the two oil return line is associated with a first panel.

Finally, the invention relates to a check valve for a control system of a device for changing the compression ratio of a cylinder unit, which can be arranged in a connecting rod connecting rod of a connecting rod and a pressure chamber of a support cylinder oil hole.

State of the art

The compression ratio ε of a reciprocating internal combustion engine denotes a ratio of a volume of the entire cylinder space to a volume of the compression space. An increase in the efficiency of the reciprocating internal combustion engine can be achieved by increasing the compression ratio, resulting in a total reduction in fuel consumption at the same power of the reciprocating internal combustion engine results. When increasing the compression ratio, however, it must be taken into account that in spark-ignited reciprocating internal combustion engines with the increase in full-load operation, the tendency to knock of the relevant cylinder units increases. The knocking is caused by an uncontrolled self-ignition of the fuel-air mixture.

In part-load operation, in which the charge is lower, however, the compression ratio could be increased to improve the corresponding partial load efficiency, without thereby the aforementioned knocking would occur. As a result, however, that it is altogether expedient to operate the reciprocating internal combustion engine in part-load operation with a relatively high compression ratio and in full-load operation with a reduced compression ratio compared to this. Depending on the operation of the reciprocating internal combustion engine, therefore, the compression ratio would have to be adjusted accordingly, so be changed.

Incidentally, a change in the compression ratio is particularly advantageous for supercharged reciprocating internal combustion engines with spark ignition, since in this case a low compression ratio is predetermined with regard to the charge pressure achieved with the charge, the compression increasing to improve the thermodynamic efficiency in unfavorable regions of a corresponding engine characteristic is.

In addition, it is possible to change the compression ratio generally depending on other operating parameters of the reciprocating internal combustion engine, such as. of driving conditions of the motor vehicle, operating points of the internal combustion engine, signals of a knock sensor, exhaust gas values, etc.

Among other things, devices are known from the state of the art in which the compression ratio is adjusted via an eccentric, which is arranged within a connecting rod eye of the connecting rod. This eccentric is received on its outer circumferential surface of the connecting rod eye, while an eccentric to the longitudinal center axis of the Pleuelauges extending bore of the eccentric serves as a piston pin bearing for receiving a piston pin.

An adjustment of the eccentric by the rotation thereof is effected by the engine forces occurring in the cylinder unit between the connecting rod on the one hand and the piston pin or the crank pin on the other hand, ie load forces resulting from the mass and gas forces. In the working cycle of the cylinder unit, the acting forces change continuously. It is expedient to connect the eccentric with two actuating pistons, which attack on this to its rotation and support via tabs. Thus, the rotational movement supported by the two adjusting pistons and a provision of the eccentric, which can occur due to the forces acting on the eccentric with different directions of force, are avoided. The adjustment of the eccentric in the respective rotary positions is controlled by a switching valve designed as a directional control valve, so that each cylinder unit of the reciprocating internal combustion engine is assigned in each case a switching valve, via which the compression ratio of the cylinder unit is set.

A control system and a check valve provided for such a control system are according to some aspects of claims 1, 6 of the DE 10 2012 112 434 A1 known. By means of the control system, a device for changing the compression ratio of a reciprocating internal combustion engine is adjusted in one of its two positions. The device is provided for changing the effective length of the connecting rod with a arranged in a connecting rod eye of a connecting rod eccentric. Within the eccentric provided with two diametrically extending tabs extends a piston pin bore, in which a piston connecting a working piston with the connecting rod is arranged. At the tabs in each case engages a piston rod of the device, wherein the piston rods are connected to support piston. Support cylinders which receive the support pistons are supplied with hydraulic fluid from a connecting rod bearing via oil lines, in each of which a non-return valve which prevents backflow. From sections of the oil lines, which extend between the check valve and the pressure chamber, branches off in each case an oil return line. Within a connecting rod of the connecting rod two 2/2-way valves are arranged, each of these is associated with the oil return lines of the directional control valves. In a first embodiment, both valves are connected to a hydraulic fluid ventilation, via which the pressure medium of the respective oil return line is discharged into the crankcase. According to a further embodiment, the pressure medium is to be passed from a gas-side supporting cylinder in the connecting rod bearing, while the mass-force side support cylinder for the control of the pressure medium, which is located in this, via the associated directional control valve with the crankcase is connectable.

Furthermore, from the DE 10 2010 016 037 A1 a control system for actuating two interacting with an adjusting actuator piston for a device for changing a compression ratio of a reciprocating internal combustion engine known whose switching valve designed as a directional control valve has a spool, which is provided with two axially spaced apart control piston same outer diameter. The two control pistons connect in their two positions optionally one of the oil return lines with a vent hole through which the engine oil can be discharged without pressure into an oil pan of the reciprocating internal combustion engine. At one end of the spool there is an actuating device designed as a ballpoint pen mechanism, which is acted upon at an end face with the engine oil pressure of the connecting rod bearing.

The DE 10 2013 107 127 A1 discloses a control system for actuating two cooperating with an adjusting actuator piston provided for a device for varying the compression ratio of a cylinder unit of a reciprocating internal combustion engine, wherein the adjusting element is arranged in a connecting rod eye of a connecting rod and adjustable by the engine power of the reciprocating internal combustion engine in two different positions. Other such control systems show the DE 10 2014 220 175 A1 . DE 10 2012 112 481 A1 and DE 10 2013 111 617 A1 ,

Disclosure of the invention

The object of the invention is to provide an advantageous embodiment and arrangement of the control system, wherein the control system has advantages both in terms of its function and its manufacture and arrangement within the connecting rod.

This object is solved by the independent claims 1 and 6. Advantageous embodiments of the invention are set forth in the dependent claims, each of which taken alone or in various combinations with each other may constitute an aspect of the invention.

The control system is provided for actuating two cooperating with an adjusting actuator piston for a device for changing the compression ratio of a cylinder unit of a reciprocating internal combustion engine, wherein the adjusting element in a connecting rod of a Pleuels arranged and is adjustable by the engine forces of the reciprocating internal combustion engine in two different positions. In these two positions are guided in support cylinders single-acting actuator piston, which together with the support cylinders each form a pressure chamber, in a retracted or extended position. The pressure chambers are on the one hand via an oil line in which a check valve is arranged, connected via a connecting rod bearing with an oil gallery. On the other hand, the pressure chambers are in each case via an oil return line, which branches off between the check valve and the pressure chamber from the oil line, with a switching device in connection, so that either one of the two oil lines is pressure relieved via the switching device. Pressure medium can thus flow into the pressure chamber via the oil line and the opening check valve. With appropriate switching of the switching device, the pressure medium can flow out of the pressure chamber via a portion of the oil line and the branching from this oil return line.

According to the patent claim 1 is in a control system, which, as explained above, each of the two oil return lines to be assigned a first aperture. It is inventively provided that this first aperture is integrated into the respective check valve. Therefore, an aperture bore made with a small diameter may already be provided in the check valve and need not be provided within the corresponding oil return lines formed as a bore within the connecting rod. It is possible to provide the two check valves together with the aforementioned sections of the oil lines and the oil return lines, the portion of the fluid line and the directional control valve in a control module, which is insertable into a receiving bore of the connecting rod.

The first diaphragm has an orifice bore, which radially penetrates a cylindrically designed check valve housing and opens into the corresponding oil return line. After the manufacture of the check valve housing, which is provided with a valve seat, consequently, the corresponding orifice bore is produced by a radial drilling operation. Through this aperture, a constant Absinkverhalten the corresponding actuating piston is achieved at different lubricating oil temperatures.

Furthermore, the above object is achieved in a check valve for a control system of a device for changing the compression ratio of a cylinder unit, which is arranged in a connecting rod bearing a connecting rod and a pressure chamber of a support cylinder oil hole, according to the patent claim 6, characterized in that in a hollow cylindrical check valve housing , upstream of a blocking body in the reverse direction, at least one radially extending diaphragm bore is provided, to which an oil return bore leading to a directional control valve can be connected. As already explained, the fine aperture bore can be produced in the hollow cylindrical check valve housing with little manufacturing effort before a blocking body, a valve spring and a check valve cover are used in this and the entire check valve is inserted into the connecting rod.

In contrast to the aforementioned solutions, the connecting rod assembly according to DE 10 2012 112 434 A1 two separate directional control valves and also no fluid bore, via which a hydraulic actuation and determination of this way valves can be done in their switching positions. Furthermore, the shutters shown in a first embodiment are not integrated in the check valves, but arranged within the oil return lines. After DE 10 2010 016 037 A1 Although a spool of the directional control valve is hydraulically actuated, but this is mechanically locked by a ballpoint pen mechanism in its switching positions. In addition, in the context of this known control system, both the oil lines and the oil return lines are guided to the support cylinder and connected thereto. In addition, no screens are provided in this control system.

In a further embodiment of the solution specified in claim 1, the directional control valve in each of the two switching positions in each case connect one of the oil return lines to the connecting rod bearing or the oil supply line. The subsidized by a variable displacement lubricating oil, which has initially flowed through the corresponding oil lines and the opening check valves in the respective associated pressure chambers of the adjusting cylinder of the adjustment is returned to the connecting rod bearing in a corresponding switching of the directional control valve in its first or second switching position. With regard to the possible by the inventive design of the switching valve oil return to the control line, which alternately takes place from each of the two pressure chambers, it should be noted that the forces exerted on the adjusting piston engine power exert pressure forces of up to 90 kN, from which in the respective Pressure chamber pressures of up to 380 bar result. Therefore, the pressure medium can flow from the respective pressure chamber into the fluid line or into the connecting rod bearing.

This is a system in which the lubricating oil in the oil supply network is recuperated. As a result, the pressure losses in the lubricating oil system, which would otherwise occur in the two switching positions, significantly reduced. The respective connection of the oil return lines via the switching valve with the connecting rod bearing also has the advantage that the adjustment speeds of the adjusting piston are reduced, since a provision is made against the system pressure. As a result, the Aufsetzgeschwindigkeiten the support piston are reduced in an advantageous manner.

Furthermore, it is provided in an advantageous embodiment that spatially between the diaphragm and a locking body of the check valve, a second diaphragm is arranged, which opens into a provided in the outer circumferential surface of the check valve housing second annular groove. Thus, two diaphragm bores are provided in each check valve housing, said diaphragm bores of the first diaphragm and the second diaphragm having different bore diameters. In the check valve, which is arranged in the leading to the guest-side support cylinder oil passage, which is formed with a larger aperture diameter second aperture is connected to the corresponding oil return line. In contrast, in the check valve disposed in the mass-flow-side oil passage, the orifice bore of the second orifice having a smaller orifice diameter is connected to the corresponding oil return passage.

It follows that in the current series of reciprocating internal combustion engine for all connecting rods, whether on the gas-power side or on the mass force side identical check valves can be used. Since both orifices each open into a provided in an outer circumferential surface of the check valve housing circumferential annular groove, the check valve can be installed in any rotational position in the connecting rod, the corresponding diaphragm is always, as provided, connected to the oil return line. In this case, a web extending between the diaphragm bores is formed by the two annular grooves, so that it is prevented that the pressure medium from the unused diaphragm bore also passes into the oil return line. The two orifices can be made with very little effort and consequently also low costs on the clamped check valve body. In contrast, the cost of using two different check valves would be significantly higher, and when installing the check valves in the connecting rod would always make sure that the appropriate oil hole or the corresponding oil return line the right check valve is sorted.

In a further embodiment of the invention, it is provided that the switching device has a control valve which controls both adjusting pistons and has two switching positions and that a control spool of the directional control valve has a fluid line extending from the connecting rod bearing exclusively by a normal engine oil pressure. p _M ), compared to this increased control pressure ( p _max ) and one compared to the engine oil pressure ( p _M ) reduced reset pressure ( p _Res Is moved in conjunction with the return spring in its two switching positions and held in these, and that the directional control valve in each of the two switching positions each one of the oil return lines connects to the connecting rod bearing or the corresponding oil line. Alternatively, the directional control valve can also be actuated mechanically or electromagnetically. In the case of a mechanical actuation, this can be done, for example, by a cam element which is displaced in such a way that it actuates the spool axially projecting above the connecting rod on its end face.

Finally, it is provided in a further development of the solution according to claim 6, that in the check valve housing a first diaphragm and a second diaphragm are arranged, which are spaced apart in the axial direction of the check valve housing, and that diaphragm bores of the two diaphragms have different bore diameter.

list of figures

• 1 einen Längsschnitt durch ein Pleuel, wobei über einen mit Stützzylindern zusammenwirkenden Exzenterhebel die Lage eines Kolbenbolzenlagers in Bezug auf das Pleuel veränderbar und in eine Aufnahmebohrung des Pleuels ein Steuerungsmodul eingesetzt ist,
• 2 als Teilansicht einen Längsschnitt durch das Steuerungsmodul, in welchem ein erfindungsgemäß ausgebildetes Rückschlagventil angeordnet ist,
• 3 als Schaltplan eine erste Variante eines Steuersystems, bei dem ein Wegeventil derart im Pleuel angeordnet ist, dass dessen Längsmittelachse parallel zu einer Längsmittelachse eines Pleuellagers verläuft,
• 4 als Schaltplan eine zweite Variante eines Steuersystems, bei dem das Wegeventil gemäß der 1 über das Steuermodul im Pleuel angeordnet ist,
• 5 eine Seitenansicht des Rückschlagventils der 2,
• 6 einen Längsschnitt durch das Rückschlagventil gemäß Linie VI - VI in 5,
• 7 eine erste Ansicht auf eine untere Stirnseite des Rückschlagventils der 5 und
• 8 eine zweite Ansicht auf eine obere Stirnseite des Rückschlagventils der 5. 9 Eine Ausführungsform des Wegeventils 29.

To further explain the invention, reference is made to the figures, in which different embodiments of the invention are shown in simplified form. Show it:

• 1 a longitudinal section through a connecting rod, wherein the position of a piston pin bearing with respect to the connecting rod changeable and in a receiving bore of the connecting rod a control module is inserted via an eccentric lever cooperating with support cylinders,
• 2 as a partial view of a longitudinal section through the control module in which an inventively designed check valve is arranged,
• 3 as a circuit diagram, a first variant of a control system in which a directional control valve is arranged in the connecting rod, that its longitudinal central axis is parallel to a longitudinal central axis of a connecting rod bearing,
• 4 as a circuit diagram, a second variant of a control system in which the directional control valve according to the 1 is arranged in the connecting rod via the control module,
• 5 a side view of the check valve of 2 .
• 6 a longitudinal section through the check valve according to line VI - VI in 5 .
• 7 a first view of a lower end face of the check valve of 5 and
• 8th a second view on an upper end face of the check valve of 5 , 9 An embodiment of the directional control valve 29 ,

Detailed description of the drawing

In the 1 1 is a connecting rod for a cylinder unit of a reciprocating internal combustion engine, which partly consists of a connecting rod shaft 2 trained connecting rod upper part 3 and a connecting rod base 4 consists. The connecting rod upper part 3 and the connecting rod base 4 together form a connecting rod eye 5 over which the connecting rod 1 can be stored on a crank pin, not shown, a crankshaft. At its other end is the connecting rod top 3 with a connecting rod eye 6 provided in which a designed as an eccentric adjusting element 7 a non-illustrated piston pin turn in a within the eccentric body 7 eccentric piston pin bearing 8th can be arranged.

About the rotatable in the piston pin bearing 8th guided piston pin is also not shown working piston of a cylinder unit of the reciprocating internal combustion engine on the eccentric body 7 guided, wherein a rotation of the eccentric body 7 in a direction to set a relatively low compression ratio and its rotation in the opposite direction to set a higher compression ratio.

The eccentric body 7 is characterized by in the cylinder unit between the connecting rod 1 on the one hand and the piston pin bearing 8th and the crank pin on the other hand occurring engine forces, ie mass and gas forces adjusted. During the working process of the cylinder unit, the acting forces change continuously. With the eccentric body 7 is designed as a two-armed lever eccentric lever 9 rotatably connected, the diametrically extending tabs 10 and 11 each having piston rods 12 and 13 with single-acting actuator piston 14 and 15 are connected. Here are the piston rods 12 and 13 each pivotable via a bolt 16 with the tabs 10 and 11 connected. The adjusting pistons 14 and 15 grip on the aforementioned components on the eccentric body 7 in order to allow this twisting or to support it in the respective position. Thus, by the adjusting piston 14 and 15 the rotational movement of the eccentric body 7 supports or its provision, due to different force directions on the eccentric body 7 transmitted forces would be avoided avoided.

The adjusting pistons 14 and 15 form together with cylinder bores 17 and 18 in which they are guided, support cylinders 19 and 20 where each support cylinder 19 respectively. 20 a pressure room 21 respectively. 22 having. The support cylinder 19 is, as its diameter reveals, provided mass-force side, while the support cylinder 20 the gas-power-side support of the eccentric lever 9 serves. In the pressure chambers 21 respectively. 22 can serve as a hydraulic medium lubricating oil of the reciprocating internal combustion engine from a in the connecting rod eye 5 arranged connecting rod bearings 23 over in the 1 partially visible oil pipes 24 and 25 flow.

Furthermore, goes from the connecting rod bearing 23 a fluid bore 26 out, just like the oil pipes 24 and 25 in a receiving hole 27 opens. Throughout the disclosure, "bores" are understood to mean bores or channels which receive and direct the pressure medium. This mounting hole 27 runs inside the connecting rod shaft 2 in the transverse direction to this, ie, parallel to the connecting rod eye 6 and the connecting rod eye 5 , In this receiving hole 27 is a cylindrically designed control module 28 used.

The fluid bore closes within the control module 28 a transverse bore 30 on that in the control module 28 promoted pressure medium in the 1 non-illustrated check valves, which in the following 2 . 6 . 7 and 8th as well as schematically in the 3 and 4 represented and with the reference numerals 31 and 32 are designated. A housing 33 of the control module 28 is made of a shaft portion and has a transverse to the longitudinal axis extending valve receiving bore 34 for receiving a directional control valve 29 on. This directional valve 29 can be as 3/2 or, as in the 3 and 4 shown to be designed as a 4/2-way valve. The directional valve 29 has a longitudinally displaceable spool 35 on, the one inside the control module 28 extending section 36 the fluid hole 26 is acted upon at one end face with a control pressure and a return spring 37 on a lid 38 supported.

Here is the connecting rod bearing 23 with in the circumferential direction over a portion of the inner circumferential surface extending groove-shaped recesses 39 provided, to which the fluid bore 26 connected. An unspecified crank pin of a crankshaft, in the connecting rod 1 by means of the connecting rod bearing 23 is mounted, has an oil outlet bore, which is connected to an oil gallery of the reciprocating internal combustion engine. While a rotation of the crankshaft and thus the crank pin passes this oil outlet hole only in phases in registration with the groove-shaped recess 39 , whereby pressure pulsations in the fluid bore 26 leading to malfunction of the directional control valve 29 can be reduced to a minimum.

The 2 shows one of the two within the control module 28 provided check valves, namely the check valve 32 that in the case 33 of the control module 28 is arranged and made of a spherical closure element 40 , a compression spring 41 , a check valve body 42 and a check valve cover 43 consists. The whole unit is in an extension 44 a section 45 the oil line 24 arranged. The other check valve 31 that in the 6 is shown in section, as from the 4 from an identical section 46 the oil line 25 added. In addition, there is the possibility of the directional control valve 29 directly in the locating hole 27 to arrange and the check valves 31 and 32 inside the connecting rod 1 provided. From the 2 goes on to show that inside the check valve body 42 a first aperture 47 and a second aperture 48 are provided, which is a first aperture bore 49 larger diameter and a second aperture bore 50 have smaller diameter. The blind holes 49 and 50 are in the axial direction of the check valve body 42 spaced apart and have, as indicated above, different bore diameter. The one with respect to the second aperture bore 50 larger bore diameter executed first aperture bore 49 intended in the present arrangement via an oil return hole 51 as well as the oil well 24 with the support cylinder 19 be connected to the mass power side.

A first embodiment of the inside of the connecting rod 1 provided hydraulic control system is the 3 refer to. In this case, the directional control valve 29 designed as 4/2-way valve. The pressure medium is via the groove-shaped recess 39 extending over only a portion of the circumference of the connecting rod bearing 23 extends, phased the fluid bore 26 fed. Furthermore, according to the 3 the oil pipes 24 and 25 entering the pressure chambers 21 and 22 the support cylinder 19 and 20 open, so with the fluid bore 26 and the directional valve 29 connected, that they over the check operations alternately opening check valves 31 and 32 an oil feed into the pressure chambers 21 respectively. 22 allow, as well as over the over the aperture 47 and 48 and the oil return holes 51 and 52 at appropriately switched directional control valve 29 an oil return into the fluid hole 26 enable.

Furthermore, this solution has the advantage that the pressure chambers 21 and 22 only the oil lines 24 and 25 are connected while, as already explained, the two oil return holes 51 and 52 only between the inside of the oil lines 24 and 25 arranged check valves 31 and 32 as well as the directional valve 29 run. The illustration can be seen that the directional control valve 29 over the fluid hole 26 is hydraulically actuated and that in the two switching positions of the directional control valve 29 from the oil return holes 51 and 52 discharged pressure fluid again the fluid hole 26 and thus the connecting rod bearing 23 is fed so that oil pressure losses in the connecting rod bearing 23 and therefore also be avoided in the oil gallery.

Another embodiment of the hydraulic control system is derived from the 4 out. This hydraulic circuit diagram of 4 assumes that the fluid hole from the connecting rod bearing 23 continuously pressure medium from an oil gallery of reciprocating internal combustion engine is supplied. Also in this case, the in the fluid hole 26 occurring pressure pulsations are reduced to a minimum. In this case, as related to the 1 yields, provided for the hydraulic actuation end face 53 of the directional valve 29 to the connecting rod eye 5 aligned.

Further details of the training of the corresponding uniform check valve, which under the tax system as check valves 31 and 32 is built 5 to 8th refer to. From the 5 and 6 shows that the two blind holes 49 and 50 each in a on the outer circumferential surface of the check valve housing 42 trained annular groove 54 and 55 open, thus by a circumferential web 56 are separated from each other. In the check valve cover 43 are like that 8th reveals through holes 57 provided. The check valve body 42 has an entrance hole 58 on.

An embodiment of the directional control valve 29 can he 9 be removed. After 9 is the valve receiving bore 34 executed as a blind hole.
The spool 35 has an end face 53 on, which has a circular contact surface 60 for the return spring 37 forms. The spool 35 , on the inside surface 61 slidably guided, also has the front side 53 on that with a control pressure from control connections 62 and 63 can be acted upon, the control pressure is a normal engine oil pressure p _M , a reduced control pressure p _LOW or an increased control pressure p _HIGH may be and these different control pressures over a variable in their delivery volume oil pump, which is not shown, created.

The control connections 62 and 63 are doing with the already mentioned, in the connecting rod 2 provided fluid bore 26 connected, which emanates from an oil gallery of reciprocating internal combustion engine. Furthermore, the spool 35 control edges 64 and 65 on. In the case 33 or directly in the connecting rod 1 are in the case of the arrangement of the directional valve 29 in the control module 28 working drilling 66 and 67 provided with the inside of the housing 33 running oil return holes 51 and 52 are connected and with which the control edges 64 and 65 of the spool 35 interact. The spool 35 points next to the circular end face 53 a circular face 68 on, wherein this at a corresponding admission with a control pressure initially only at the end face 53 and then after a longitudinal displacement of the spool both on the end face 53 as well as on the face 68 is charged. The longitudinal displacement described is caused by an increased control pressure p _max , With the subsequently modulated control pressure p _M the spool remains in its second switching position, while switching to the first, in the 9 shown switching position by means of a reduced control pressure p _Res is achieved.

LIST OF REFERENCE NUMBERS

1

pleuel

2

connecting rod shaft

3

Pleueloberteil

4

Pleuelunterteil

5

Pleuellagerauge

6

connecting rod

7

designed as an eccentric adjusting element

8th

Piston pin bearing

9

Cam

10

flap

11

flap

12

piston rod

13

piston rod

14

actuating piston

15

actuating piston

16

bolt

17

bore

18

bore

19

supporting cylinders

20

supporting cylinders

21

pressure chamber

22

pressure chamber

23

connecting rod bearing

24

oil line

25

oil line

26

fluid bore

27

location hole

28

control module

29

way valve

30

cross hole

31

check valve

32

check valve

33

Housing of 28

34

Valve receiving bore for 35

35

Spool of 29

36

Section of 26

37

Return spring

38

cover

39

groove-shaped recess

40

spherical closing element

41

compression spring

42

Check valve housing

43

Check valve cover

44

extension

45

Section of 24

46

Section of 25

47

first aperture

48

second aperture

49

first aperture bore of larger diameter

50

second aperture bore of smaller diameter

51

Oil return bore

52

Oil return bore

53

Front side of 35

54

ring groove

55

ring groove

56

web

57

Through bore

58

inlet bore

59

Front side of 35

60

contact surface

61

Inner surface area

62

control connection

63

control connection

64

control edge

65

control edge

66

work well

67

work well

68

circular face

Claims (7)

Control system for actuating two interacting with an adjusting actuator piston (14 and 15) for a device for changing the compression ratio of a cylinder unit of a reciprocating internal combustion engine, wherein the adjusting element (7) in a connecting rod eye (6) of a connecting rod (1) and arranged by the engine forces of the reciprocating internal combustion engine is adjustable in two different positions, in which in the support cylinders (19 and 20) guided single-acting actuator piston (14 and 15), which together with the support cylinders (19 and 20) each form a pressure chamber (21, 22), in a retracted or extended position, wherein the pressure chambers (21 and 22) on the one hand via an oil line (24, 25), in which a check valve (31, 32) is arranged, and a connecting rod bearing (23) with an oil gallery and on the other one between the check valve (31, 32) and the pressure chamber (21, 22) of the oil line (24, 25) abz oil return line (51, 52) are connected to a switching device, so that via the switching either one of the two oil lines (24, 25) is pressure relieved, each of the two oil return line (51, 52) is associated with a first aperture (47) and wherein the first orifice (47) is integrated into the respective non-return valve (31, 32), characterized in that the first orifice (47) has an orifice bore (49) radially penetrating a cylindrically shaped check valve housing (42) and into the oil return line (52) opens. Control system after Claim 1 , characterized in that spatially between the diaphragm (47) and a blocking body (40) of the check valve (31, 32), a second diaphragm (48) is arranged, in a in the outer circumferential surface of the check valve housing (42) provided second annular groove (55 ). Control system after Claim 1 , characterized in that the first orifice bore (49) via a in an outer circumferential surface of the check valve housing (42) provided circumferential annular groove (54) is connected to the oil return line (52). Control system after Claim 2 , characterized in that the aperture bores (49 and 50) of the first aperture (47) and the second aperture (48) have different bore diameters. Control system after Claim 1 , characterized in that the switching device has a two adjusting pistons (14 and 15) controlling, two switching positions exhibiting directional control valve (29) and that a spool (35) of the directional control valve (29) via a conrod from the (23) outgoing fluid line (26) exclusively by a normal engine oil pressure (p _M ), with respect to this increased control pressure (p _max ) and with respect to the engine oil pressure (p _M ) reduced reset pressure (p _Res ) in cooperation with a return spring (37) moved into its two switching positions and held in this is, and that the directional control valve (29) in each of the two switching positions each one of the oil return lines (51, 52) with the connecting rod bearing (23) and the oil line (24, 25) connects. Check valve (31, 32) for a control system of a device for changing the compression ratio of a cylinder unit, which is connected to an oil line (24) connecting a connecting rod bearing (23) of a connecting rod (1) and a pressure chamber (21, 22) of a support cylinder (19, 20) , 25) can be arranged, characterized in that in a hollow cylindrical check valve housing (42), a locking body (40) upstream in the reverse direction, at least one radially extending orifice bore (49, 50) is provided to the one to a directional control valve (29) leading oil return bore (51, 52) can be connected. Check valve (31, 32) after Claim 6 characterized in that in the check valve housing (42) a first aperture (47) and a second aperture (48) are arranged, which are spaced apart in the axial direction of the check valve housing (42) to each other, and that aperture holes (49 and 50) of the two Apertures (47 and 48) have different bore diameters.

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