DE202017007701U1 - Hydraulic valve for adjusting a hydraulic fluid flow of a connecting rod for an internal combustion engine with variable compression - Google Patents

Abstract

Hydraulic valve (1) for adjusting a hydraulic fluid flow of a connecting rod (100) for an internal combustion engine with variable compression, with a valve housing (2) which has a first working connection (3) and a second working connection (4) as well as a supply connection (5) which can be acted upon by a hydraulic pressure of a hydraulic fluid, whereby a movable piston (6) arranged in the valve housing (2) can be displaced against the force of a prestressed spring (7), wherein at least one first check valve (8) is provided in the hydraulic valve, which feeds the hydraulic fluid supplied to a working connection (3, 4) to the supply connection (5) and the other working connection (4, 3) within the valve housing (2).

Description

Technical area

The invention relates to a hydraulic valve for adjusting a hydraulic fluid flow of a connecting rod for an internal combustion engine with variable compression with an eccentric adjusting device for adjusting an effective connecting rod length.

State of the art

In internal combustion engines, a high compression ratio has a positive effect on the efficiency of the internal combustion engine. The compression ratio is generally understood to be the ratio of the entire cylinder space before compression to the remaining cylinder space after compression. In internal combustion engines with spark ignition, in particular gasoline engines, which have a fixed compression ratio, the compression ratio may only be selected so high that so-called "knocking" of the internal combustion engine is avoided when operating at full load. However, for the far more common partial load range of the internal combustion engine, i.e. when the cylinder is low, the compression ratio could be selected with higher values without "knocking" occurring. The important partial load range of an internal combustion engine can be improved if the compression ratio can be variably adjusted. Systems with variable connecting rod lengths, for example, are known for adjusting the compression ratio.

A hydraulic valve for a connecting rod for an internal combustion engine with variable compression with an eccentric adjustment device for adjusting an effective connecting rod length is known, for example, from EN 10 2013 107 127 A1 known.

Disclosure of the invention

An object of the invention is to provide an improved hydraulic valve which enables improved control and/or regulation of the hydraulic fluid flow at low cost.

Another task is to create a connecting rod with such a hydraulic valve.

The above objects are achieved according to one aspect of the invention with the features of the independent claims.

Favorable embodiments and advantages of the invention emerge from the further claims, the description and the drawing.

A hydraulic valve is proposed for influencing, in particular for controlling and/or regulating, a hydraulic fluid flow of a connecting rod for an internal combustion engine with variable compression, with a valve housing that has a first working connection and a second working connection as well as a supply connection that can be subjected to a hydraulic pressure of a hydraulic fluid, whereby a movable piston arranged in the valve housing can be displaced against the force of a pre-tensioned spring. At least one first check valve is provided in the hydraulic valve, which feeds the hydraulic fluid supplied to a working connection to the supply connection and the other working connection within the valve housing.

The hydraulic valve according to the invention is intended for use in a connecting rod for an internal combustion engine with variable compression by means of an eccentric adjustment device. The connecting rod can, for example, have two support rods connected to corresponding pistons of two hydraulic support chambers for adjusting an eccentric. The hydraulic valve advantageously enables a shortening of the path of the hydraulic fluid, for example engine oil, flowing from one support chamber of a connecting rod into the other support chamber of the connecting rod. This prevents the hydraulic fluid from flowing back into the bearing shell and then having to be replenished by the other support chamber. It also prevents long hydraulic fluid columns from forming and the high acceleration forces acting on them from having a negative effect, which in the worst case could cause the hydraulic pressure to drop so far that a higher pressure is created in front of a check valve of the replenishing support chamber than behind the check valve. The replenishing chamber would thus only lose hydraulic fluid through leakage, but would not receive any hydraulic fluid back in return, which would cause the piston of the corresponding support chamber to sink.

The hydraulic valve according to the invention also makes it possible to produce a connecting rod with a variably adjustable length that is not only adjustable in two stages. This makes it possible to provide a cost-effective hydraulic solution for a connecting rod for an internal combustion engine with variable compression using an eccentric adjustment device.

The hydraulic valve can be arranged in the connecting rod body of a connecting rod and have a piston that can be moved in a housing as a control piston with at least one check valve that is arranged in the housing or on the piston. net. A hydraulic fluid path can thus be formed from one working port of the hydraulic valve to the other working port and the supply port.

To achieve a position for high compression (ε _high ), one end face of the piston can be subjected to hydraulic pressure. The valve spring, on which the piston rests, counteracts this and holds the piston in the end position as long as the spring force is greater than the resulting force from the hydraulic pressure acting on the end face. Hydraulic fluid can only flow from one working connection, or the so-called gas force (GKS (gas force side)) - support chamber of the connecting rod via the check valve into the second, so-called mass force (MKS (mass force side)) - support chamber. In addition, the GKS chamber can supply hydraulic fluid from the supply connection via the check valve. The flow from the MKS chamber takes place via an orifice in front of the check valve in order to limit the adjustment speed of the eccentric adjustment device of the connecting rod. This allows hydraulic fluid to flow from the MKS chamber towards the GKS chamber, while no hydraulic fluid can flow back or out of the GKS chamber. The GKS chamber fills and the MKS chamber empties so that the position for high compression can be achieved.

To achieve a position for low compression (ε _ıow ), a force on the piston face caused by the hydraulic pressure can be greater than the counterforce of the valve spring. The piston then moves to the other end position. Hydraulic fluid from the GKS chamber can either flow preferentially into the MKS chamber via an orifice or via a smaller orifice in the direction of a tank drain. The orifice in the direction of the tank drain is advantageous if the GKS chamber is larger than the MKS chamber, as this has a larger hydraulic fluid volume and not the entire hydraulic fluid volume is used up by the MKS chamber. In addition, the MKS chamber can feed hydraulic fluid from the supply connection via the check valve.

This allows hydraulic fluid to flow from the GKS chamber towards the MKS chamber and tank drain, while no hydraulic fluid can flow back or out of the MKS chamber. The MKS chamber fills and the GKS chamber empties so that the low compression position can be reached.

In an intermediate control position of the hydraulic valve, the hydraulic fluid pressure can be regulated in such a way that the spring force is equal to the resulting force from the hydraulic pressure acting on the front face. In this way, both chamber drain holes can be closed or at least almost closed with the piston, which means that the eccentric lever can no longer be adjusted and remains in its current position.

By specifically regulating the hydraulic fluid pressure, the piston can be moved in a controlled manner and a support chamber can be emptied or the complementary support chamber can be filled. In this way, a targeted adjustment can be achieved and, when the desired adjustment angle is reached, the piston can be reset so that both support chambers are closed or at least almost closed and the eccentric lever remains in its position. In this way, a desired adjustment angle and thus a desired connecting rod length can be achieved by regulating the hydraulic fluid pressure.

If both support chambers of the connecting rod have the same volume, no drain towards the tank drain is required.

The orifices in front of the check valve can be optional. Through design measures or targeted controls, the piston can limit the opening cross-section of the drain holes in the housing and thus create a throttling point that can fulfill the same function.

Alternatively, a second hydraulic fluid supply inlet can be implemented on the connecting rod, whereby the piston face can be pressurized independently of the hydraulic pressure of the engine oil. This means that it is sufficient to regulate only this control pressure and not the entire hydraulic pressure of the engine oil supply connection.

External check valves could be omitted. The edges on the piston can be advantageously arranged in such a way that the drain holes are slightly open in the middle position of the piston, i.e. there is an under-coverage, and both support chambers can supply hydraulic fluid via the check valve.

The outside diameter of the hydraulic valve can be advantageously increased, which means that external check valves can also be integrated into the hydraulic valve, creating a single hydraulic module. Band spring check valves, plate check valves and ball check valves can be used as check valves.

The hydraulic valve according to the invention can be provided as a press-fit variant or with a clearance fit with sealing elements.

The hydraulic valve can alternatively be implemented as a mechanical variant, in which the piston positioning is not carried out via hydraulic fluid pressure but via a switching gate as in the known switch design.

The check valve to the supply connection can alternatively be provided by another check valve in the housing or an external check valve in the connecting rod.

According to an advantageous embodiment, the piston can be selectively locked in a first switching position and in a second switching position. Instead of a continuously adjustable hydraulic valve, a two-stage hydraulic valve with two end positions can also be used. The piston can be locked in the end positions as the first and second switching positions in order to achieve a stable position of the connecting rod for a desired compression.

According to an advantageous embodiment, the piston can be continuously adjustable. Alternatively, the piston can be continuously adjustable in the form of a control valve, whereby intermediate positions of the piston and thus the hydraulic fluid supply to the support chambers of the connecting rod can also be set. A desired compression can also be set as an intermediate value between high and low. This makes it possible to make the engine control of an internal combustion engine more cost-effective.

According to an advantageous embodiment, a control position can be provided in which the first working connection and the second working connection are closed. In this way, both chamber drain holes of the connecting rod can be closed or at least almost closed with the piston, whereby the eccentric lever can no longer be adjusted and remains in its current position.

According to an advantageous embodiment, the supply connection can have a second check valve which blocks the hydraulic fluid from flowing back towards the supply connection. In this way, the entire hydraulic fluid volume of one support chamber can be used to fill the other support chamber. In addition, hydraulic fluid can be fed via the second check valve if the volume of the second support chamber is larger than the volume of the first support chamber and more hydraulic fluid is therefore required to fill the second support chamber.

According to an advantageous embodiment, the second check valve can be provided as a band check valve. A band check valve, for example as a thin spring steel band, represents a simple and cost-effective way of implementing a check valve. In addition, a very space-saving variant can be implemented in this way, since the metal band can be attached to an inner wall of a housing bore in a space-saving manner.

According to an advantageous embodiment, the band check valve can be designed as a ring band that is pre-tensioned radially outwards. The ring band, for example made of spring steel, can be pre-tensioned against the inner wall of the housing so that it can be opened radially from the outside to the inside with the appropriate hydraulic pressure. The opening pressure can be adjusted accordingly by choosing the material and the thickness of the ring band.

According to an advantageous embodiment, the ends of the ring band can be designed to overlap. If the ends of the ring band overlap, the ends slide over one another when the ring band is pressed radially inwards and cannot get caught on one another. This is a simple way of ensuring reliable operation of the check valve.

According to an advantageous embodiment, the first check valve can be arranged on the valve housing or on the piston. The first check valve can be arranged in a simple and space-saving manner inside the valve housing and thus cover both working connections. A very favorable arrangement directly on the piston is also possible, whereby the installation space can be used effectively and reliable operation of the check valve can be ensured.

According to an advantageous embodiment, the first check valve can comprise two plate elements and a spring element acting on the plate elements, wherein the plate elements each cover an opening of the piston associated with the first working connection and an opening associated with the second working connection. In this way, a very space-saving check valve can be implemented which can open and close in two spatial directions, whereby both working connections can advantageously be supplied.

According to an advantageous embodiment, a fluid path between the second working connection and the first working connection can have an orifice. The hydraulic fluid flow can be conveniently regulated by means of the orifice, since a throttling function can be implemented in this way. Such an orifice is particularly advantageous when one support chamber has a larger hydraulic volume than the other support chamber.

According to an advantageous embodiment, a fluid path between the second working connection and a tank drain can have an orifice. The orifice can be used to suitably influence and in particular control the proportion of the hydraulic fluid flow that flows to the first working connection and the proportion that flows to the tank drain. The orifice to the tank drain can preferably have a smaller opening than the opening to the first working connection.

According to a further aspect of the invention, the use of the hydraulic valve as a control valve, switching valve or proportional valve is proposed. In particular, continuous adjustability of the piston makes use in the control range appear advantageous. The hydraulic valve according to the invention can thus be used advantageously for adjustable connecting rods, gear applications or swivel motors, for example.

According to a further aspect of the invention, a connecting rod for an internal combustion engine with variable compression is proposed, with an eccentric adjustment device for adjusting an effective connecting rod length by means of a hydraulic valve. The eccentric adjustment device has two cylinders and/or two support chambers. Both an inlet for supplying hydraulic fluid to the cylinders or support chambers via a supply line and an outlet for discharging hydraulic fluid from the cylinders or support chambers are provided. The two cylinders each have a piston that is slidably guided in a cylinder bore and is connected to a support rod.

An eccentric can be operated via the support rods to adjust the effective length of the connecting rod. The hydraulic valve allows the connecting rod to be made with a variably adjustable length, which can be adjusted in more than just two stages. This means that a cost-effective hydraulic solution for a connecting rod for an internal combustion engine with variable compression can be presented using an eccentric adjustment device.

The hydraulic valve can be arranged in the connecting rod body of the connecting rod and have a piston that can be moved in a housing as a control piston with at least one check valve, which can be arranged in the housing or on the piston. A hydraulic fluid path can thus be formed from one working connection of the hydraulic valve to the other working connection and the supply connection.

To achieve a position for high compression (ε _high ), one end face of the piston can be subjected to hydraulic pressure. The valve spring, on which the piston is supported, counteracts this and holds the piston in the end position as long as the spring force is greater than the resulting force from the hydraulic pressure acting on the end face. Hydraulic fluid can only flow from one working connection, or the so-called gas force (GKS (gas force side)) - support chamber of the connecting rod via the check valve into the second, so-called inertia force (MKS (inertia force side)) - support chamber. In addition, the GKS chamber can supply hydraulic fluid from the supply connection via the check valve. The flow from the MKS chamber takes place via an orifice in front of the check valve in order to limit the adjustment speed of the eccentric adjustment device of the connecting rod. This allows hydraulic fluid to flow from the MKS chamber towards the GKS chamber, while no hydraulic fluid can flow back or flow out of the GKS chamber. The GKS chamber fills and the MKS chamber empties so that the high compression position can be reached.

To reach a position for low compression (ε _low ), a force on the piston face caused by the hydraulic pressure can be greater than the counterforce of the valve spring. The piston then moves to the other end position. Hydraulic fluid from the GKS chamber can either flow preferentially into the MKS chamber via an orifice or via a smaller orifice in the direction of a tank drain. The orifice in the direction of the tank drain is advantageous if the GKS chamber is larger than the MKS chamber, as this has a larger hydraulic fluid volume and not the entire hydraulic fluid volume is used up by the MKS chamber. In addition, the MKS chamber can feed hydraulic fluid from the supply connection via the check valve.

This allows hydraulic fluid to flow from the GKS chamber towards the MKS chamber and tank drain, while no hydraulic fluid can flow back or out of the MKS chamber. The MKS chamber fills and the GKS chamber empties so that the low compression position can be reached.

In an intermediate control position of the hydraulic valve, the hydraulic fluid pressure can be regulated in such a way that the spring force is equal to the resulting force from the hydraulic pressure acting on the front surface. In this way, both chamber drain holes can be closed or at least almost closed with the piston, whereby the eccentric lever can no longer be adjusted and remains in its current position. By specifically regulating the hydraulic fluid pressure, the piston can be moved in a controlled manner and a support chamber can be emptied or the entire mental support chamber can be filled. In this way, a targeted adjustment can be effected and, at the desired adjustment angle, the piston can be reset so that both support chambers are closed or almost closed and the eccentric lever remains in its position. In this way, a desired adjustment angle and thus a desired connecting rod length can be achieved by regulating the hydraulic fluid pressure. According to an advantageous embodiment, at least one first check valve can be provided in the hydraulic valve, which feeds hydraulic fluid draining from one cylinder or support chamber to the supply line and to the other cylinder or support chamber within the valve housing. The hydraulic valve advantageously enables the path of the hydraulic fluid, for example engine oil, draining from one support chamber of a connecting rod into the other support chamber of the connecting rod to be shortened. This prevents the hydraulic fluid from flowing back into the bearing shell and then having to be replenished from the other support chamber.

According to a further aspect of the invention, a connecting rod with a hydraulic valve is proposed, wherein the eccentric adjustment device comprises a swivel motor which has a rotor mounted in a stator. At least one first support chamber and at least one second support chamber are formed between at least one rotor blade of the rotor and at least one stator blade of the stator, wherein a volume of the first support chamber and a volume of the second support chamber can be changed complementarily to one another by adjusting the rotor relative to the stator.

In contrast to the connecting rod described above, a swivel motor can be used as an alternative drive for the eccentric adjustment device. In this way, a rotation of the swivel motor can be transferred in a mechanically simple manner to a rotation of an eccentric of the eccentric adjustment device. This means that the length of the connecting rod can be reliably adjusted. This allows the connecting rod to be adjusted quickly and a very space-saving design of the connecting rod can be implemented.

According to an advantageous embodiment, at least one first check valve can be provided in the hydraulic valve, which directs a hydraulic fluid flowing out of one support chamber to a supply line and the other support chamber within the valve housing. The hydraulic valve advantageously enables a shortening of the path of the hydraulic fluid, for example engine oil, flowing out of one support chamber of a connecting rod into the other support chamber of the connecting rod. This prevents the hydraulic fluid from flowing back into the bearing shell and then having to be replenished from the other support chamber.

Short description of the drawings

Further advantages emerge from the following description of the drawings. An embodiment of the invention is shown schematically in the drawings. The drawings, the description and the claims contain numerous features in combination. The person skilled in the art will expediently also consider the features individually and combine them into further useful combinations.

• 1 ein Hydraulikventil nach einem Ausführungsbeispiel der Erfindung in einer Seitenansicht;
• 2 das Hydraulikventil gemäß 1 in einem Längsschnitt;
• 3 das Hydraulikventil gemäß 1 in einer anderen Seitenansicht mit eingezeichneten Schnittebenen A-A, B-B und C-C;
• 4 das Hydraulikventil gemäß 1 in isometrischer Darstellung;
• 5 das Hydraulikventil gemäß 1 in einem Querschnitt B-B in 3;
• 6 das Hydraulikventil gemäß 1 in einem Querschnitt C-C in 3;
• 7 eine schematische Hydraulikanordnung eines Pleuels nach einem Ausführungsbeispiel der Erfindung in einer Regelstellung;
• 8 die schematische Hydraulikanordnung eines Pleuels gemäß 7 in einer Stellung für hohe Verdichtung;
• 9 das Hydraulikventil gemäß 1 in einem Längsschnitt A-A in 3 in der Stellung für hohe Verdichtung;
• 10 die schematische Hydraulikanordnung eines Pleuels gemäß 7 in einer Stellung für niedrige Verdichtung;
• 11 das Hydraulikventil gemäß 1 in einem Längsschnitt A-A in 3 in der Stellung für niedrige Verdichtung;
• 12 ein Pleuel nach einem Ausführungsbeispiel der Erfindung in einer Vorderansicht; und
• 13 ein Pleuel nach einem weiteren Ausführungsbeispiel der Erfindung mit einem Schwenkmotor in einem Längsschnitt.

Examples include:

• 1 a hydraulic valve according to an embodiment of the invention in a side view;
• 2 the hydraulic valve according to 1 in a longitudinal section;
• 3 the hydraulic valve according to 1 in another side view with section planes AA, BB and CC marked;
• 4 the hydraulic valve according to 1 in isometric representation;
• 5 the hydraulic valve according to 1 in a cross section BB in 3 ;
• 6 the hydraulic valve according to 1 in a cross section CC in 3 ;
• 7 a schematic hydraulic arrangement of a connecting rod according to an embodiment of the invention in a control position;
• 8 the schematic hydraulic arrangement of a connecting rod according to 7 in a high compression position;
• 9 the hydraulic valve according to 1 in a longitudinal section AA in 3 in the high compression position;
• 10 the schematic hydraulic arrangement of a connecting rod according to 7 in a low compression position;
• 11 the hydraulic valve according to 1 in a longitudinal section AA in 3 in the low compression position;
• 12 a connecting rod according to an embodiment of the invention in a front view; and
• 13 a connecting rod according to a further embodiment of the invention with a swivel motor in a longitudinal section.

Embodiments of the invention

In the figures, identical or similar components are numbered with identical reference symbols. The figures merely show examples and are not to be understood as limiting.

The 1 to 6 a hydraulic valve 1 according to the invention for adjusting, in particular for controlling and/or regulating, a hydraulic fluid flow of a connecting rod for an internal combustion engine with variable compression can be seen in various views and sections. 1 shows the hydraulic valve 1 in a side view, while in 2 a longitudinal section and in 3 another side view with the section planes AA, BB and CC marked is shown. 4 shows the hydraulic valve 1 in isometric view. The 5 and 6 show cross sections BB and CC.

As in particular in 2 As can be seen, the hydraulic valve 1 has a valve housing 2 which has a first working connection 3 and a second working connection 4 as well as a supply connection 5 which can be subjected to a hydraulic pressure of the hydraulic fluid, whereby a movable piston 6 arranged in the valve housing 2 can be displaced against the force of a pre-tensioned spring 7. As can be seen from the 2 , 3 and 4 As can be seen, the working connections 3 and 4 are formed from several radial bores in the valve body 2 and open into annular grooves 32, 33 which at least partially encircle the valve housing 2.

As particularly in the 1 , 2 and 4 As can be seen, the supply connection 5 comprises radial bores, which also open into an at least partially circumferential annular groove 34, which merges into an axial groove 35 and a bore 36, via which the piston 6 can be subjected to hydraulic pressure as described below. The radial bores of the supply connection 5 are in the cross section BB in 5 while the radial bores of the second working connection 4 in the cross section CC in 6 can be recognized.

According to the invention, at least one first check valve 8 is provided in the hydraulic valve 1, which, within the valve housing 2, directs a hydraulic fluid flowing from one cylinder or a support chamber to the supply connection 5 and the other cylinder or the other support chamber. For this purpose, the hydraulic fluid supplied to the working connection 3, 4 can be directed to the supply connection 5 and the other working connection 4, 3.

The first check valve 8 can be arranged on the valve housing 2 or, as shown, on the piston 6. It comprises two annular plate elements 21, 22 guided on the piston 6 and a spring element 23 acting on the plate elements 21, 22, wherein the plate elements 22, 23 each cover an opening 24, 25 or bore of the piston 6 assigned to the first working connection 3 and a second working connection 4.

The piston 6 is preferably designed to be continuously adjustable so that the piston or the eccentric of the eccentric adjustment device can be adjusted to a desired position. The hydraulic valve 1 can thus be used in principle as a control valve, switching valve or proportional valve.

For example 2 As can be seen, the supply connection 5 has a second check valve 9, which blocks a return flow of the hydraulic fluid from the hydraulic valve 1 in the direction of the supply line P. As can be seen, the second check valve 9 is provided as a band check valve. The band check valve is designed as a radially outwardly prestressed ring band, the ends of which are designed to overlap, as shown in particular in 5 can be recognized.

The 7 , 8 and 10 Complete circuits of a connecting rod can be seen in a schematic hydraulic arrangement. Cylinders 11, 12, pistons 13, 14 and support rods 15, 16 of an eccentric adjustment device are shown schematically as examples. 7 shows a control position of the hydraulic valve 1, in which an outlet 17, 18 of both cylinders 11, 12 is closed. The 8 and 10 The end positions for high compression (ε-high) in a first switching position S1, or low compression (ε-low) in a second switching position S2 can be seen.

9 shows the hydraulic valve 1 in detail in a longitudinal section AA in 3 in the high compression position, while 11 the hydraulic valve 1 in a longitudinal section AA in the position for low compression.

The connecting rod, which is only shown in outline, has a connecting rod body and an eccentric adjustment device, which is only shown in the form of two support rods 15, 16, with two cylinders 11, 12, or two support chambers, wherein both an inlet 19, 20 for supplying hydraulic fluid to the cylinders 11, 12, or the support chambers via a supply line 27, which supplies a supply pressure P, and an outlet 17, 18 for discharging hydraulic fluid from the cylinders 11, 12, or the support chambers are provided.

According to one embodiment, the eccentric adjustment device can have two cylinders 11, 12, each with a piston 13, 14 which is displaceably guided in a cylinder bore and connected to a support rod 15, 16.

From the 2 and 7 the control position can be seen in which the outlets 17, 18 of both cylinders 11, 12 are closed. The hydraulic pressure P is regulated in such a way that the spring force of the spring 7 is equal to the resulting force from the supply pressure P, which acts on the front face 26. By specifically regulating the hydraulic pressure P, the piston 6 can be moved in a controlled manner and cylinder 11 or 12 can be emptied or the complementary cylinder 12 or 11 can be filled. In this way, a targeted adjustment can be achieved. When the desired adjustment angle is reached, the piston 6 can be moved back again so that both cylinders 11, 12 are closed or at least almost closed and the eccentric adjustment device remains in its position. In this way, a desired adjustment angle and thus a desired connecting rod length can be achieved by regulating the hydraulic pressure.

The 8 and 9 the end position ε-high of the connecting rod can be seen in the switching position S1.

An end face 26 of the piston 6 is subjected to the supply pressure P via a supply line 27 in the connecting rod body 10 and the described supply connection 5 in the hydraulic valve 1. The spring 7 counteracts this and holds the piston 6 in the end position as long as the spring force is greater than the resulting force from the supply line 27 acting on the end face 26.

Hydraulic fluid can only flow from the cylinder 11 into the cylinder 12 via the first check valve 8, as indicated by the arrows in 8 and 9 , which symbolize the fluid path 40. In addition, the cylinder 12 can feed via the band check valve 9 from the supply line 27 and the supply connection 5 formed in the valve housing 2.

The discharge from the cylinder 11 takes place via an orifice 37 in front of the check valve 8 in order to limit the adjustment speed.

In this position, hydraulic fluid can drain from the cylinder 11, while no hydraulic fluid can drain from the cylinder 12, so that the cylinder 11 empties and the cylinder 12 fills and the end position ε-high is set.

The 10 and 11 the end position ε-low of the connecting rod can be seen in the switching position S2.

The force on the front face 26 due to the supply pressure P is greater than the counterforce of the spring 7, so that the piston 6 moves to its left-hand end position.

Like the one in 10 and 11 As can be seen from the arrows shown, which symbolize the fluid path 40, hydraulic fluid can flow from the cylinder 12 either via an orifice 28 preferably in the direction of the cylinder 11 or via a smaller orifice 29 in the direction of a tank drain T. The orifice against the tank drain T is only necessary if the cylinder 12 is larger than the cylinder 11, since it has a larger volume and not all of the hydraulic fluid is consumed by the cylinder 11. In addition, the cylinder 11 can feed hydraulic fluid from the supply line 27 via the band check valve 9.

Hydraulic fluid can flow out of the cylinder 12 towards the cylinder 11 and towards the tank drain T, while no hydraulic fluid can flow out of the cylinder 11, so that the cylinder 11 fills and the end position ε-low is set.

The piston 6 could also be lockable optionally in the first switching position S1 and in the second switching position S2.

In the following, alternative embodiments of the invention are described which are not explicitly shown in the drawing.

If both cylinders 11, 12 or support chambers have the same volume, no drain towards tank T is required.

The orifices 28 in front of the check valve 8 are optional. Through design measures or targeted controls, the plate elements 21, 22 can limit the opening cross-section of the drain holes 3, 4 in the valve housing 2 and thus create a throttle point that would fulfill the same function. The piston face 26 could be controlled independently of the engine oil pressure using a second supply line with a hydraulic pressure that is independent of the engine oil pressure.

The 7 , 8 and 10 The external check valves 30, 31 shown could be omitted if the edges of the piston 6 are arranged in such a way that the drain holes 3, 4 are slightly open in the middle position of the piston 6 (under-coverage) and both cylinders 11, 12 can supply hydraulic fluid via the band check valve 9.

Alternatively, the external check valves 30, 31 can also be integrated into the hydraulic valve 1 to form a single hydraulic module.

Instead of a continuously adjustable hydraulic valve 1, a two-stage valve with two end positions can also be provided.

The hydraulic valve 1 shown is intended as a press-fit variant. A clearance fit with sealing elements can also be provided.

The hydraulic valve 1 can also be designed as a mechanical variant, in which the piston positioning is not carried out via hydraulic fluid pressure, but via a switching gate.

The band check valve 9 can also be replaced by another check valve in the valve housing 2 or an external check valve in the connecting rod.

12 shows a connecting rod 100 according to an embodiment of the invention in a front view. The connecting rod 100 for an internal combustion engine with variable compression comprises an eccentric adjustment device 102 for adjusting an effective connecting rod length by means of a hydraulic valve 1.

The eccentric adjustment device 102 has two cylinders 11, 12, or support chambers. There are both an inlet 19, 20 (not visible, see 7 ) for supplying hydraulic fluid to the cylinders 11, 12, or support chambers via a supply line 27 as well as a drain 17, 18 (not visible, see 7 ) for draining hydraulic fluid from the cylinders 11, 12 or the support chambers. The two cylinders 11, 12 each have a piston 13, 14 which is guided displaceably in a cylinder bore and is connected to a support rod 15, 16. The support rods 15, 16 are provided for actuating an eccentric lever 103 which is connected to the eccentric 104.

In hydraulic valve 1, as shown in the 1 to 6 shown, at least one first check valve 8 is provided, which feeds a hydraulic fluid flowing out of a cylinder 11, 12 or a support chamber to the supply line 27 and the other cylinder 12, 11 or the other support chamber within the valve housing 2. The supply line 27 (not shown) opens into the bearing shell 114 of the pin bearing eye 115, via which the supply pressure P is available.

The two external check valves 30, 31 are arranged in transverse bores in the connecting rod body 10.

13 shows a connecting rod 100 according to a further embodiment of the invention with a swivel motor 126 in a longitudinal section. The connecting rod 100 also has an eccentric adjustment device 102, which comprises an eccentric 104.

The eccentric 104 has a receptacle 130 for a piston pin. In this alternative, however, the eccentric 104 is driven by a swivel motor 126 arranged in the connecting rod eye 118, which has a rotor 127 mounted in a stator 128, wherein at least one first support chamber 152 and at least one second support chamber 154 are formed between at least one rotor blade 131 of the rotor 127 and at least one stator blade 132 of the stator 128, wherein a volume of the first support chamber 152 and a volume of the second support chamber 154 can be changed complementarily to one another by adjusting the rotor 127 relative to the stator 128.

The connecting rod body 10 has receptacles 122 for connecting rod screws on both sides of the crank bearing eye 115, via which the crank bearing eye 115 can be closed. In the hydraulic valve 1, at least one first check valve 8 is provided, which, within the valve housing 2, feeds a hydraulic fluid draining from a support chamber 152, 154 to the supply line 27 and the other support chamber 154, 152.

QUOTES INCLUDED IN THE DESCRIPTION

This list of documents listed by the applicant was 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 accepts no liability for any errors or omissions.

Cited patent literature

• DE 102013107127 A1 [0003]

Claims (17)

Hydraulic valve (1) for adjusting a hydraulic fluid flow of a connecting rod (100) for an internal combustion engine with variable compression, with a valve housing (2) which has a first working connection (3) and a second working connection (4) as well as a supply connection (5) which can be acted upon by a hydraulic pressure of a hydraulic fluid, whereby a movable piston (6) arranged in the valve housing (2) can be displaced against the force of a prestressed spring (7), wherein at least one first check valve (8) is provided in the hydraulic valve, which feeds the hydraulic fluid supplied to a working connection (3, 4) to the supply connection (5) and the other working connection (4, 3) within the valve housing (2). Hydraulic valve according to Claim 1 , wherein the piston (6) can be selectively locked in a first switching position (S1) and in a second switching position (S2). Hydraulic valve according to Claim 1 , wherein the piston (6) is continuously adjustable. Hydraulic valve according to Claim 3 , wherein a control position is provided in which the first working connection (3) and the second working connection (4) are closed. Hydraulic valve according to one of the preceding claims, wherein the supply connection (5) has a second check valve (9) which blocks a return flow of the hydraulic fluid in the direction of the supply connection (5). Hydraulic valve according to Claim 5 , wherein the second check valve (9) is provided as a band check valve. Hydraulic valve according to Claim 6 , wherein the band check valve is designed as a ring band prestressed radially outward. Hydraulic valve according to Claim 7 , with the ends of the ring band overlapping. Hydraulic valve according to one of the preceding claims, wherein the first check valve (8) is arranged on the valve housing (2) or on the piston (6). Hydraulic valve according to Claim 9 , wherein the first check valve (8) comprises two plate elements (21, 22) and a spring element (23) acting on the plate elements (21, 22), wherein the plate elements (21, 22) each cover an opening (24, 25) of the piston (6) assigned to the first working connection (3) and an opening (24, 25) assigned to the second working connection (4). Hydraulic valve according to one of the preceding claims, wherein a fluid path between the second working port (4) and the first working port (3) has an orifice (28). Hydraulic valve according to one of the preceding claims, wherein a fluid path between the second working port (4) and a tank drain (T) has an orifice (29). Use of the hydraulic valve according to one of the preceding claims as a control valve, switching valve or proportional valve. Connecting rod (100) for an internal combustion engine with variable compression, with an eccentric adjusting device (102) for adjusting an effective connecting rod length by means of a hydraulic valve (1) according to one of the Claims 1 until 12 , wherein the eccentric adjustment device (102) has two cylinders (11, 12) and/or two support chambers, and wherein both an inlet (19, 20) for supplying hydraulic fluid to the cylinders (11, 12) or support chambers via a supply line (27) and an outlet (17, 18) for discharging hydraulic fluid from the cylinders (11, 12) or the support chambers are provided, wherein the two cylinders (11, 12) each have a piston (13, 14) which is slidably guided in a cylinder bore and is connected to a support rod (15, 16). Connecting rod after Claim 14 , wherein at least one first check valve (8) is provided in the hydraulic valve (1), which, within the valve housing (2), feeds a hydraulic fluid flowing out of a cylinder (11, 12) or a support chamber to the supply line (27) and to the other cylinder (12, 11) or the other support chamber. Connecting rod (100) with a hydraulic valve (1) according to one of the preceding Claims 1 until 12 , wherein the eccentric adjustment device (102) comprises a swivel motor (126) which has a rotor (127) mounted in a stator (128), wherein at least one first support chamber (152) and at least one second support chamber (154) are formed between at least one rotor blade (131) of the rotor (127) and at least one stator blade (132) of the stator (128), wherein a volume of the first support chamber (152) and a volume of the second support chamber (154) can be changed complementarily to one another by adjusting the rotor (127) relative to the stator (128). Connecting rod after Claim 16 , wherein at least one first check valve (8) is provided in the hydraulic valve (1), which, within the valve housing (2), feeds a hydraulic fluid flowing out of a support chamber (152, 154) to a supply line (27) and to the other support chamber (154, 152).

Images