CN111664001A

CN111664001A - Switching valve for controlling hydraulic fluid flow and variable compression ratio internal combustion engine connecting rod with same

Info

Publication number: CN111664001A
Application number: CN202010004615.7A
Authority: CN
Inventors: 亚历山大·穆德拉
Original assignee: Eco Holding 1 GmbH
Current assignee: Eco Holding 1 GmbH
Priority date: 2019-03-08
Filing date: 2020-01-03
Publication date: 2020-09-15
Anticipated expiration: 2040-01-03
Also published as: CN111664001B; DE102019133520A1

Abstract

The present invention relates to a switching valve for controlling a hydraulic fluid flow, in particular a hydraulic fluid flow of a control rod, having a valve body in which an axially movable tap element is arranged, which can be selectively moved into a first switching position or a second switching position. At least two through-holes are provided in the tapping element, which through-holes extend through the tapping element. In the first switching position, a fluid connection between the first hydraulic connection and the supply connection is produced via one of the passage openings, and in the second switching position, a fluid connection between the second hydraulic connection and the supply connection is produced via the other of the passage openings. At least one throttle device is provided, by means of which a hydraulic preloading of the hydraulic fluid can be generated in a defined use in one of the switching positions. A throttle device is associated with the tap element and is deactivated in a further switching position of the switching positions.

Description

Switching valve for controlling hydraulic fluid flow and variable compression ratio internal combustion engine connecting rod with same

Technical Field

The invention relates to a switching valve for controlling the hydraulic fluid flow, in particular for a connecting rod of an internal combustion engine with a variable compression ratio, having an eccentric adjustment device for adjusting the effective connecting rod length. The invention also relates to a connecting rod with such a switching valve.

Background

In internal combustion engines, a high compression ratio plays a positive role in the efficiency of the internal combustion engine. Compression ratio is generally understood as the ratio of the total cylinder volume before compression to the remaining cylinder volume after compression. However, in the case of externally ignited internal combustion engines, in particular gasoline motors with a fixed compression ratio, the compression ratio can only be selected so high that so-called "knocking" of the internal combustion engine is avoided during full-load operation. However, for the more frequently occurring partial load regions of the internal combustion engine, i.e. with fewer cylinder charges, a compression ratio with a higher value is selected without "knocking" occurring. When the compression ratio is variably adjustable, the important part load region of the internal combustion engine can be improved. For adjusting the compression ratio, systems are known, for example, with variable connecting rod lengths, which operate the eccentric adjustment of the connecting rod by means of a switching valve which can be actuated hydraulically or mechanically.

Known switching valves are known, for example, from DE102012112461a 1. The switching element described in said document can be locked in two switching positions by means of a detent ball and a spring, wherein the detent ball interacts with two detent recesses formed in the tap element.

The rotational speed-dependent acceleration of the relatively long hydraulic fluid column located in the connecting rod of the oil used as hydraulic fluid can generate a pressure difference. The pressure difference can act both positively and negatively, i.e. it can accelerate the hydraulic fluid column, so that the cylinder of the connecting rod is assisted in emptying and filling, but also in the way of the emptying and filling of the connecting rodA cylinder body. Firstly, for the cylinder on the inertial force side (MKS) of the connecting rod, the effect can work negatively. The acceleration of the hydraulic fluid column can cause that no more positive pressure differences are formed in front of and behind the check valve on the MKS side, which pressure differences cause that a replenishment of hydraulic fluid can be fed into the MKS chamber. Due to leakage and other effects, the cylinder is always deprived of hydraulic fluid, which leads to a stepwise, slow adjustment of the eccentric by multiple revolutions. This also has the effect of changing the effective length of the connecting rod from a low compression ratio of (a)_low) To a high compression ratio of (_high) As a result of the positions of the low compression ratio, the position of the high compression ratio corresponds to one switching position of the switching valve, and the position of the low compression ratio corresponds to the other switching position of the switching valve. What is called drift is said to occur here. This occurs primarily in the case of motor loads with high inertial forces (tensile and compressive forces on the connecting rod) and low gas pressures (compressive forces on the connecting rod). Connecting rod to_highThe possible adjustment of the direction of (a) by the inertial force in the direction of tension cannot be completely reset again by the inertial force in the direction of compression and the gas pressure.

When the hydraulic cylinder of the connecting rod is able to achieve a hydraulic preload, an improved operation is advantageously shown, as described in DE102017113984a 1. There, the GKS (gas pressure side) chamber can be brought to a low compression ratio_low) The supplementally supplied hydraulic fluid is directed directly into the MKS chamber in the position of (1), since the hydraulic fluid which is pressed into the MKS chamber by the GKS chamber by the gas pressure acting on the connecting rod has a much higher pressure than the hydraulic fluid pressure of the hydraulic supply in the bearing shell of the connecting rod. Hydraulic fluid can thereby be forced from the GKS chambers into the MKS chambers.

With eccentric adjustment means other than connecting rods in position_lowIn addition to the positional stability in (1), i.e. the connecting rod is reset to its final position after a revolution_lowThe positional stability in the rotation and the rigidity of the link can be improved. During the pivoting, there is always a movement of the eccentric lever, since the hydraulic fluid column also has a certain flexibility and thus always results in supporting the piston in the filled hydraulic chamberSinking to some extent. If the connecting rod is completely reset again until the end of the pivoting, the person says "stable in position". However, when the angle changes on the eccentric or on the set of lever elements, the respective support piston strikes the chamber bottom of the cylinder upon return, which can negatively affect the service life. For this reason, the setting speed of the eccentric adjustment device can be limited by the throttle position in the hydraulic line. Advantageously, the preloaded MKS hydraulic fluid column acting in pressure sinks less than the hydraulic fluid column that is not preloaded. Less sinking of the hydraulic fluid column means less lever movement, whereby the position can be improved_lowPosition stability in (1).

Disclosure of Invention

The object of the invention is to provide an improved switching valve with a preload of hydraulic fluid.

A further object is to provide a connecting rod with an improved switching valve.

The aforementioned object is achieved by a switching valve or a connecting rod having the features of the invention.

Advantageous embodiments and advantages of the invention are given by the examples, the description and the figures.

According to one aspect of the invention, a switching valve for controlling a hydraulic fluid flow, in particular a control rod, is proposed, which has a valve body in which an axially movable tap element is arranged, which can be selectively moved into a first switching position or a second switching position. At least two through-holes are provided in the tapping element, which through-holes extend through the tapping element.

In the first switching position, a fluid connection between the first hydraulic connection and the supply connection is produced via one of the passage openings, and in the second switching position, a fluid connection between the second hydraulic connection and the supply connection is produced via the other of the passage openings. At least one throttle device is provided, by means of which a hydraulic preloading of the hydraulic fluid can be generated in one of the switching positions in a predetermined use. The at least one throttle device is assigned to the tapping element. The throttle device can be deactivated in a further switching position of the switching positions.

The throttle device can advantageously be a preloaded throttle device which is deactivated in a switching state, preferably in the connecting rod, corresponding to a state with a high compression ratio. This makes it possible to implement the switching valve in a compact manner, with a small number of bores in the connecting rod when the switching valve is used as intended. Advantageously, all throttling devices which should make the hydraulic fluid flow controllable can be integrated in the switching valve.

Advantageously, the preload is produced in such a switching state of the connecting rod in which it is desired to suck hydraulic liquid in the preloaded hydraulic liquid column by means of a preload throttle which can be deactivated, and the preload is switched off in a further switching state. This is the case, for example, when the hydraulic cylinder is moved slightly, as is the case with high compression ratios. If an unthrottled intake of hydraulic fluid into the cylinder bore on the inertial force side can be achieved, a counter-impact of the piston in the cylinder bore can be avoided.

According to an advantageous embodiment of the switching valve, the throttle device can be moved with the tap element. In particular, the throttle device can be brought into a position in which the hydraulic fluid flow can be passed in one of the switching positions and into a deactivated position in the other of the switching positions. The embodiment is compact and the throttle device can be realized relatively simply in the tapping element. The typical diameter of switching valves for connecting rods is below 15mm, so that the diameter of the tapping element is still smaller.

According to an advantageous embodiment of the switching valve, the throttle device can be arranged in one of the passage openings of the tap element. This allows a simple production of the throttle device, in particular as a throttle bore. In this way, the through-hole can be machined from one side, and the throttle device can be placed at the end of the through-hole. Alternatively, the machining can be effected from both sides, so that the throttle device is arranged in the through-bore, for example centrally or eccentrically. The positioning of the restriction may be set as desired.

According to an advantageous embodiment of the switching valve, the through-opening can be arranged axially offset in the tap element and extends diametrically through the tap element. In this way, a through-opening can be provided in a simple manner through the diameter of the tap element, which through-opening can be connected or blocked to the hydraulic line on both sides of the tap element. Depending on the passage opening, the fluid connection can be produced or closed separately. Such a tapping element can be produced cost-effectively.

According to an advantageous embodiment of the switching valve, the valve body can have at least one throttle device. The compact design of the switching valve allows the linkage to be simplified.

According to an advantageous embodiment of the switching valve, the valve body can have at least one throttle device, which is arranged in a connecting section between one of the hydraulic connections and the tap element. Such a throttle device in the hydraulic line in the valve body upstream of the tap element can be advantageously provided in order to achieve a lower leakage of hydraulic liquid in the switching valve, since the circumferential length of the opening of the hydraulic line at the tap element can be reduced. This results in a smaller gap width in the event of a smaller leakage of hydraulic fluid at the transition between the hydraulic line and the through-opening.

According to an advantageous embodiment of the switching valve, the tap element can have at least one bypass path running parallel to the through-opening. Through this, a fluid connection between the hydraulic interfaces is possible in the deactivated preloaded throttle device. The tap element can in particular have at least one bypass path running parallel to the through-opening, wherein the at least one bypass path branches off from the through-opening. The bypass branch can advantageously be branched off in the through-opening by means of the throttle device on the side of the throttle device directed toward the hydraulic connection. Through which hydraulic fluid can bypass the restriction. In the switching position, through which the throttle device (preloaded throttle device) flows, hydraulic fluid can flow out of the tap element through the bypass path without throttling. The hydraulic fluid can be throttled in the valve body if necessary.

In accordance with an advantageous embodiment of the switching valve, the valve body can have at least one connecting line which, in one of the switching positions, connects the respective through-opening at both ends of the through-opening. The two through-openings can advantageously have a connecting line. At least one check valve and/or at least one throttle device can be arranged in the connecting line. The suction of hydraulic fluid can be replenished if necessary by means of connecting lines in the valve body.

According to an advantageous embodiment of the switching valve, in each of the switching positions, one of the connecting lines can be connected to the respective through line and the associated bypass line can be connected to the other of the connecting lines. In this way, in the switching position, in which the throttle device (preload throttle device) can be flowed through in the passage opening and a connection between the hydraulic connection and the supply connection can be produced, hydraulic fluid can bypass the throttle device and can flow into the connecting line. The associated hydraulic connection is preferably the hydraulic connection on the inertial force side (MKS).

According to an advantageous embodiment of the switching valve, at least one throttle device can be arranged in one of the connecting lines. The switching valve provides a compact design with a simplified hydraulic fluid guide in the connecting rod when the switching valve is applied as intended.

According to an advantageous embodiment of the switching valve, at least one check valve can be arranged in one of the connecting lines. In particular, at least one check valve may be arranged in one of the connecting lines, which check valve is able to flow in the direction of the hydraulic connection. The switching valve provides a compact design with a simplified hydraulic fluid guide in the connecting rod when the switching valve is applied as intended. Different sized check valves may be provided for the inertia force side and the gas pressure side check valves. Thus, for example, the check valve in the connecting line arranged on the through-opening on the inertial force side can be larger than the check valve in the connecting line arranged on the through-opening on the gas pressure side. The check valve can advantageously be designed as a ball check valve, in which the ball is used as a closure body. Different ball diameters can be selected for the MKS side and the GKS side accordingly.

Alternatively, according to a further aspect, a switching valve with one or more check valves integrated into the switching valve in such a connecting line can be provided without a preloaded throttle device being arranged in one of the connecting lines.

According to an advantageous embodiment of the switching valve, the connection section can be arranged between the hydraulic connection and a tap element in which the throttle device is arranged. This allows throttling when emptying the respective cylinder bore.

According to an advantageous embodiment of the switching valve, at least one throttle device can be arranged upstream of the non-return valve in the one connecting line. This allows throttling when emptying the respective cylinder bore.

According to an advantageous embodiment of the switching valve, the valve body can have a supply connection common to both switching positions. The supply connection can be advantageously configured such that it can fix the filter element in the supply line of the connecting rod. The supply connection can advantageously be the only transfer point for the hydraulic fluid in the connecting rod.

In accordance with an advantageous embodiment of the switching valve, the two connecting lines can be fluidically connected in the two switching positions. This can advantageously be ensured by a side branch path. A check valve arranged in the connecting line ensures the desired flow direction.

According to an advantageous embodiment of the switching valve, the tap element can have a stop element, with which an axial movement of the tap element in the valve body can be limited. The tap-off element may in particular have a stop element, with which an axial movement of the tap-off element in the valve body can be limited, wherein the stop element can be brought into a latching position in the valve body by a spring in the tap-off element. Such a stop element offers a reliable possibility for defining the switching path of the tap element. Therefore, the switching function having two switching positions can be reliably ensured.

According to an advantageous embodiment of the switching valve, the valve body can have a recess which is provided for interacting with a latching element for axially fixing the valve body in the connecting rod. In this way, not only axial loss prevention of the changeover valve but also rotation prevention of the changeover valve can be advantageously achieved. A low insertion force can be used when fitting the switching valve into the connecting rod, which simplifies the assembly.

According to a further aspect of the invention, a connecting rod for an internal combustion engine having a variable compression ratio is proposed, which connecting rod has an eccentric adjustment device for adjusting the effective connecting rod length, wherein the adjustment path of the eccentric adjustment device is adjustable by means of a switching valve according to the invention.

According to an advantageous embodiment of the connecting rod, the eccentric adjusting device can have at least one and preferably two cylinders each having a piston, which is guided displaceably in a cylinder bore and is connected to the support rod, and wherein an inlet is provided for the supply of hydraulic fluid into the cylinders and an outlet is provided for the discharge of hydraulic fluid from the cylinders.

According to an advantageous embodiment of the connecting rod, in a first switching position the outlet of the first cylinder can be connected to the hydraulic fluid circuit via the tap element, and in a second switching position the outlet of the second cylinder can be connected to the hydraulic fluid circuit via the tap element.

According to an advantageous embodiment of the connecting rod, a first recess can be provided at least on a part of the circumference of the stroke bearing bore for hydraulically connecting the switching valve to a hydraulic fluid circuit for supplying hydraulic fluid from the hydraulic fluid circuit to the inlet opening into the cylinder. The recess can be embodied in the section of the stroke bearing bore on the connecting rod cover and/or in the section of the stroke bearing bore on the connecting rod body.

According to an advantageous embodiment of the connecting rod, a first recess can be provided at least on a part of the circumference of the stroke bearing bore for hydraulically connecting the switching valve to a hydraulic fluid circuit for supplying hydraulic fluid from the hydraulic fluid circuit via a common line to an inlet opening into the cylinder. The switching valve according to the invention advantageously results in a simplified line routing, wherein only the supply line from the hydraulic fluid circuit to the switching valve has to be implemented.

According to an advantageous embodiment of the connecting rod, a filter element can be arranged in the connecting bore between the recess and the switching valve. In particular, a filter element can be arranged in the connecting bore between the recess and the switching valve, said filter element being held captive by the switching valve. The filter element may be, for example, a perforated small tube that is pressed in. Alternatively, other configurations of the filter element are possible. When the filter element is inserted into the corresponding bore or fixed by means of a changeover valve, the filter element advantageously does not require further fixing means.

In accordance with an advantageous embodiment of the connecting rod, a latching element can be arranged in the connecting rod cover, said latching element engaging in a recess of the valve body and axially fixing said valve body in the connecting rod cover. In addition to the axial fixing of the switching valve in the connecting rod, a rotation prevention can also be brought about by this. Furthermore, it is advantageous that a low insertion force is necessary when installing the switching valve in the connecting rod.

Drawings

Further advantages are given by the following description of the figures. Embodiments of the invention are schematically illustrated in the drawings. The figures, description and claims contain a number of features in combination. The skilled person will also appropriately observe these features individually and combine them into other meaningful combinations.

It is shown exemplarily that:

FIG. 1 is a high compression ratio in a partially cut-away illustration with a switching valve according to the present invention, according to an embodiment of the present invention_highThe connecting rod according to the present invention in the state of (1);

fig. 2 is a detailed illustration of a connecting rod cover of the connecting rod with the switching valve inserted into the bore according to fig. 1 in a semi-transparent illustration;

fig. 3 is a detailed illustration of a connecting rod cover of the connecting rod without the switching valve inserted according to fig. 1 in a semi-transparent illustration;

FIG. 4 is at a high compression ratio_highA hydraulic schematic diagram of the switching valve in the switching position of (1);

FIG. 5 is at a high compression ratio_highIn an isometric view of a switching valve according to an embodiment of the invention in a switching position;

FIG. 6 is a longitudinal cross-sectional view of the switching valve according to FIG. 5 taken along A-A in FIG. 7 with section line B-B, C-C, E-E;

FIG. 7 is a longitudinal cross-sectional view of the switching valve according to FIG. 5 taken along B-B in FIG. 6 with section line A-A, D-D, F-F;

FIG. 8 is a cross-sectional view of the switching valve according to FIG. 5 taken along C-C of FIG. 6;

FIG. 9 is a cross-sectional view of the switching valve according to FIG. 5 taken along line D-D of FIG. 7;

FIG. 10 is a cross-sectional view of the changeover valve according to FIG. 5 taken along line E-E of FIG. 6;

FIG. 11 is a cross-sectional view of the changeover valve according to FIG. 5 taken along section F-F of FIG. 7;

FIG. 12 is at a low compression ratio_lowA hydraulic schematic diagram of the switching valve in the switching position of (1);

FIG. 13 is at a low compression ratio_lowIn an isometric view, the switching valve from fig. 5 in the switching position of (a);

FIG. 14 is a longitudinal cross-sectional view of the switching valve according to FIG. 5 taken along A-A in FIG. 15 with section line B-B, C-C, E-E;

FIG. 15 is a longitudinal cross-sectional view of the switching valve according to FIG. 5 taken along B-B in FIG. 14 with section line A-A, D-D, F-F;

FIG. 16 is a cross-sectional view of the changeover valve according to FIG. 5, taken along C-C of FIG. 14;

FIG. 17 is a cross-sectional view of the switching valve according to FIG. 5 taken along line D-D of FIG. 15;

FIG. 18 is a cross-sectional view of the changeover valve according to FIG. 5 taken along line E-E of FIG. 14;

fig. 19 is a cross-sectional view of the switching valve according to fig. 5 taken along F-F of fig. 15.

Detailed Description

In the drawings, like reference numerals are used to designate like or similar components. The drawings are shown by way of example only and are not to be construed in a limiting sense.

Fig. 5 to 11 and 13 to 19 show different views and sectional views of an exemplary embodiment of a switching valve 5 according to the invention in different switching positions, which is provided in particular for the otherwise substantially known connecting rod 1 shown in fig. 1 for a variable compression ratio of an internal combustion engine.

The connecting rod 1 illustrated in fig. 1 has a connecting rod comprising a connecting rod body 21 and a connecting rod cover 24 and comprises an eccentric adjusting device 2, which is adjustable at least in sections and has an eccentric 4, and which is arranged in a connecting rod bearing bore, which is not further labeled.

The eccentric adjustment device 2 serves to adjust the effective connecting rod length. The link length is defined as the distance from the center axis of the stroke bearing hole 20 to the center axis of the link bearing hole. High compression ratio_highState of (2) is lower than the compression ratio_lowHas a higher link length.

The rotation of the adjustable eccentric adjustment device 2 is caused by the inertial and load forces of the internal combustion engine, which act on the eccentric adjustment device 2 during the working stroke of the internal combustion engine. During the working stroke, the direction of the force acting on the eccentric adjustment device 2 changes continuously. The rotary or adjusting movement is assisted by pistons 6, 7 integrated in the connecting rod 1, which are loaded with hydraulic fluid, in particular with oil. The pistons 6, 7 counteract a resetting of the eccentric adjustment device 2 as a result of the variable force action direction of the force acting on the eccentric adjustment device 2.

The pistons 6, 7 are operatively connected to the lever 3 of the eccentric adjusting device 2 on both sides by means of

support rods

8, 9. The pistons 6, 7 are arranged displaceably in the cylinder bores 10, 11 and are not visible for the passage of hydraulic fluid via hydraulic lines not shownFor example, the check valve. The shut-off valve prevents a return flow of hydraulic fluid from the cylinder bores 10, 11 or the cylinders 12, 13 into the hydraulic line and enables a supplementary suction of hydraulic fluid into the cylinders 12, 13. All or at least some of the hydraulic lines connected to the cylinder bores 10, 11 interact with the switching valve 5 according to the invention via an inlet, not shown in the sectional view, for the supply of hydraulic fluid from the switching valve 5 into the cylinders 12, 13 formed by the cylinder bores 10, 11, and via an outlet, not shown in the sectional view, for the discharge of hydraulic fluid from the cylinders 12, 13 to the switching valve 5. The switch position S1 of the switch valve 5 corresponds to the low compression ratio of the connecting rod 1_lowWherein the other switching position S2 of the switching valve 5 corresponds to the high compression ratio of the connecting rod 1_highIn the position of (shown in fig. 1). The supply line is here a connection for supplying the connecting rod 1 with hydraulic liquid, for example via a recess 25 in the stroke bearing bore 20 of the connecting rod 1.

The machining of the connecting rod 1 and in particular of the connecting rod body 21 is costly and therefore cost-intensive. It can thus be provided advantageously that the connection of the inlet and the outlet is effected primarily by means of a switching valve 5, which switching valve 5 is provided for controlling the hydraulic fluid flow. A non-illustrated shut-off valve can optionally be integrated into the switching valve 5 and accordingly open or close the throughflow of hydraulic fluid in the direction of the inlet.

The outlet can bypass a shut-off valve in the changeover valve 5 and can be provided with a throttled bore. When the inlet and outlet and supply lines are based on the switching valve 5, the production of the connecting rod body 21 can be significantly simplified.

The supply line can connect the changeover valve 5 with the oil circuit of the internal combustion engine. However, if the inlet and outlet are implemented by the switching valve 5, then the hydraulic fluid is distributed in principle in the switching valve 5 via a corresponding connection between the two cylinders 12, 13, i.e. the supply lines are essentially only used to draw excess or missing hydraulic fluid out of the switching valve 5 or to supplement the switching valve 5 due to leakage or due to different volumes of the cylinders 12, 13.

Further simplification can be produced by providing the inlet and outlet as a single duct.

The shut-off valve can be configured as a check valve, in particular as a ball check valve or as a conical seat valve.

Fig. 2 and 3 show a detailed illustration of the link cover 24 of the link 1 according to fig. 1 in a semi-transparent illustration. Fig. 2 shows a switching valve 5 according to the invention installed in a bore 43 in the connecting rod cover 24. Fig. 3 shows an illustration of the switching valve 5 without its opening in the bore 43.

A supply line 34 for the supply connection of the changeover valve 5 extends from the recess 25 in the connecting rod cover 24. The outlet lines 29, 30 extend from the non-illustrated cylinders 12, 13 to the hydraulic connections of the switching valve 5. The supply line 34 is guided through a section 36 in which the filter element 26 is mounted, which may be designed, for example, as a perforated small tube. The section 36 intersects the supply line 34, so that the filter element 26 can be inserted into the section 36 and held in a loss-proof manner by the switching valve 5 which is installed.

In fig. 2, a latching element 37, for example in the form of a rod, is arranged below the switching valve, said latching element being able to be inserted into the connecting rod cover 24 and fixed, for example from the side. The latching element 37 engages in a recess on the valve body of the switching valve 5 and serves to axially fix the switching valve 5 and as an anti-rotation means for the switching valve 5.

As can be seen, with the switching valve 5 according to the invention, only three lines are necessary in the connecting rod 1.

However, the switching valve 5 described in detail below can also be provided for all other connecting rods of an internal combustion engine with a variable compression ratio, which have an eccentric adjusting device for adjusting the effective connecting rod length and at least two cylinder bores or hydraulic chambers. For example, the eccentric adjustment of the connecting rod can be designed with a so-called wobble motor system.

FIG. 4 shows the compression ratio at high_highThe hydraulic pressure principle diagram of the switching valve 5 in the switching position of (1). FIG. 12 shows the compression ratio at low_lowThe hydraulic pressure principle diagram of the switching valve 5 in the switching position of (1).

The switching valve 5 comprises a tap element 27 which is axially movable in a valve body 28 and which in this example has two through

openings

31, 32. The through-

openings

31, 32 connect the supply port 56 to the

hydraulic port

52 or 54 depending on the switching position of the tap element 27. The through-line 31 has a throttle device 61 and connects the hydraulic connection 52 on the gas pressure side (GKS) to the supply connection 56. The through-line 32 can flow freely and connects the hydraulic port 54 on the inertia force side (MKS) to the supply port 56.

A throttle device 61 arranged in the through bore 31 is movable with the tap element 27.

In the tap element 27, a

respective bypass path

41, 42 emerges from each through-

opening

31, 32. Two connecting

lines

44, 45 are provided in the valve body 28, which connect the two ends of the respective throughflow through

openings

31, 32 depending on the switching position of the tap element 27. In each case one shut-off valve in the form of a

check valve

22, 23 is arranged in each of the two connecting

lines

44, 45, which check valve permits a throughflow of the respective through

opening

31, 32 from the supply connection-side end to the hydraulic connection-side end.

In the connecting line 44, which is connected to both ends of the through-opening 32 in the illustrated switching position, the throttle device 60 is arranged in front of the check valve 22, as seen in the flow direction. A further throttle 58 is arranged in the connecting section 46 leading from the MKS hydraulic connection 54 to the through-opening 32 in the tap element 27. The return line 44 opens into the connecting portion 46 between the hydraulic connection 54 and the throttle device 58.

In the shown switching position_highHydraulic fluid flows out of the MKS-side cylinder via the drain line 30 to the hydraulic port 54, flows into the through bore 32 via the throttle device 58 in the connecting section 46, and flows via the bypass path 42 to the supply port 56. The hydraulic fluid passes via the bypass path 42 into the connecting line 45 and, as long as the pressure, viewed in the flow direction of the non-return valve 23, is greater than the pressure downstream of the non-return valve 23, it can pass to the hydraulic connection 52 on the GKS side and via the outlet line 29 to the cylinder on the GKS side.

The throttle device 61 arranged in the through bore 31 is deactivated in this case by the switching position of the tap element 27, which serves as a preload throttle.

FIG. 5 illustrates, in an isometric display as a top view, at high compression ratio_highIn the switching position of the switching valve 5 according to the embodiment of the invention. What can be identified are the tap element 27 in the valve body 28 as well as the

hydraulic connections

52, 54 and the supply connection 56.

The double arrows on the

hydraulic interfaces

52, 54 and the supply interface 56 indicate that hydraulic fluid can flow in both directions.

A throttle 58 in the connecting section 46 can be identified in the hydraulic connection 54.

Fig. 6 to 11 show different sectional views of the switching valve 5 in a switching position with a high compression ratio. Fig. 6 shows a longitudinal section through the switching valve 5 according to fig. 5 with section line B-B, C-C, E-E through a-a in fig. 7, fig. 7 shows a longitudinal section through the switching valve according to fig. 5 with section line a-A, D-D, F-F through B-B in fig. 6, fig. 8 shows a cross section through the switching valve 5 according to fig. 5 through C-C in fig. 6, fig. 9 shows a cross section through the switching valve 5 according to fig. 5 through D-D in fig. 7, fig. 10 shows a cross section through the switching valve 5 according to fig. 5 through E-E in fig. 6, and fig. 11 shows a cross section through the switching valve 5 according to fig. 5 through F-F in fig. 7.

As can be seen in fig. 6 and 7, the tap element 27 has a stop element 50, with which the axial movement of the tap element 27 in the valve body 28 can be limited. The stop element 50 is arranged, for example, transversely to the through-

openings

31, 32. The stop element 50 can be installed in the valve body 28 in a latched position by means of a spring 39 in the tap element 27. The spring 39 extends away from the tap member 27. The spring 39 is preferably designed as a compression spring.

The valve body 28 has a recess 40 on its outer circumference, in which a latching element 37 for axially fixing the valve body 28 in the connecting rod 1 is arranged. The catch element 37 is indicated by a broken line. The latching elements 37 are designed in the form of rods, so that they extend in a tangential direction relative to the outer circumference of the valve body 28.

The stop element 50 projects into a recess 38 in the outer circumference of the valve body 28, which recess is separated from the middle by a latching element 37. The position of the stop element 50 on one side or the other side of the latching element 37 corresponds to one or the other switching position of the switching valve 5, respectively. When changing the switching position, the stop element 50 is pressed against the force of the spring 39 into the interior of the tap element 27 and thus over the latching element 37. In this case, the tip of the stop element 50 is designed as an inclined surface, so that the stop element 50 can be lifted when the switching element, not shown, actuates and axially displaces the tap element 27. In this switching position, the stop element 50 is positioned to the left of the detent element 37 in fig. 6.

The two through

bores

31, 32 preferably extend diametrically through the tap element 27 and are spaced apart from one another in the axial direction.

The

check valves

22, 23 are fixed in the connecting

lines

44, 45. This fastening can be achieved by means of fastening pins, which are pressed into the valve body 28. The fixing pin additionally serves as a stroke limiting means. Advantageously, a single fixing pin 62 can be provided for both

check valves

22, 23, which extends through both connecting

lines

44, 45. The check valve 23, which extends in the connecting line 45 between the supply connection 56 and the GKS-side hydraulic connection 52 in the valve body 28, is designed with a larger ball than the check valve 22 in the other connecting line 44.

As can be taken from fig. 7 to 9, the hydraulic fluid is in the switching position_highFrom the MKS-side hydraulic connection 54 into the connecting section 46, via the throttle 58 into the through bore 32 and from there via the bypass path 42 to the supply connection 56. Conversely, hydraulic fluid can flow from the supply port 56 through the return line 45 via the check valve 23 into the GKS-side hydraulic port 52 (fig. 10, 11).

FIG. 12 shows the compression ratio at low_lowThe hydraulic pressure principle diagram of the switching valve 5 in the switching position of (1).

FIG. 13 shows the compression ratio at low_lowIn an isometric view as a top view, switching valve 5 from fig. 5 in the switching position of (a). Fig. 14 shows a longitudinal section through the switching valve 5 according to fig. 5 along a-a in fig. 15 with a section line B-B, C-C, E-E. Fig. 15 shows a longitudinal section through the switching valve 5 according to fig. 5 along B-B in fig. 14 with a section line a-A, D-D, F-F. Fig. 16 shows a cross-sectional view of the switching valve 5 according to fig. 5, taken along C-C in fig. 14. Fig. 17 shows a cross-sectional view of the switching valve 5 according to fig. 5, taken along D-D in fig. 15. Fig. 18 shows a cross-sectional view of the switching valve 5 according to fig. 5, taken along E-E in fig. 14, and fig. 19 shows a cross-sectional view of the switching valve 5 according to fig. 5, taken along F-F in fig. 15.

In this switching position, the stop element 50 is positioned to the right of the detent element 37 in fig. 14 (fig. 14).

In the switching position of the switching valve 5_lowThe GKS chamber can direct the additionally fed hydraulic fluid directly into the MKS chamber, since the hydraulic fluid which is pressed into the MKS chamber by the GKS chamber by the gas pressure acting on the connecting rod 1 has a much higher pressure than the hydraulic fluid pressure of the hydraulic supply in the bearing shell of the connecting rod 1 (fig. 1). This can be seen in fig. 14 to 19.

Hydraulic fluid can flow from the GKS-side hydraulic connection 52 through the connecting section 47 into the through bore 31 with the preload throttle 61 and from there to the supply connection 56.

Hydraulic fluid can flow from the supply connection 56 via the connecting line 45 with the non-return valve 23 to the hydraulic connection 52 on the GKS side.

In the transfer of hydraulic fluid from the GKS-side hydraulic port 52 to the MKS-side hydraulic port 54, a portion of the hydraulic line (connecting line 44) extends in a direction through the longitudinal axis of the valve body 28.

The throttle device 60 is integrated as a valve path in the check valve 22, as can be seen in particular from fig. 18 and 19.

Claims

1. A switching valve (5) for controlling a hydraulic fluid flow, in particular for controlling a hydraulic fluid flow of a connecting rod (1), having a valve body (28) in which an axially movable tap element (27) is arranged, which can be selectively moved into a first switching position (S1) or a second switching position (S2),

wherein at least two through-holes (31, 32) are provided in the tapping element (27), which through-holes extend through the tapping element (27),

wherein in the first switching position (S1) a fluid connection between the first hydraulic connection (52) and the supply connection (56) is produced by one of the through-openings (31, 32) and in the second switching position (S2) a fluid connection between the second hydraulic connection (54) and the supply connection (56) is produced by the other of the through-openings (31, 32), and

wherein at least one throttle device (61) is provided, by means of which a hydraulic preload of the hydraulic fluid can be generated in a defined use in one of the switching positions (S1, S2),

it is characterized in that the preparation method is characterized in that,

the throttle device (61) is associated with the tap element (27), and the throttle device (61) is deactivated in a further one of the switching positions (S1, S2).

2. Switching valve as in claim 1, characterized in that the throttle device (61) is movable with the tap element (27), in particular in the one of the switching positions (S1, S2) can be brought into a position in which it can be flown through by the hydraulic fluid flow and in the other of the switching positions (S1, S2) can be brought into a deactivated position.

3. Switching valve as in claim 1 or 2, characterized in that the throttle device (61) is arranged in one of the through openings (31, 32) of the tap element (27).

4. Switching valve as in any claim hereinbefore, characterized in that the through-bore (31, 32) is arranged axially offset in the tap element (27) and extends diametrically through the tap element (27).

5. Switching valve as in any claim hereinbefore, characterized in that the valve body (28) has at least one throttling device (58, 60).

6. Switching valve as in any claim hereinbefore, characterized in that the valve body (28) has at least one throttle device (58) which is arranged in a connecting section (46) between one of the hydraulic connections (52, 54) and the tap element (27).

7. Switching valve as in any one of the preceding claims, characterized in that the tap element (27) has at least one bypass path (41, 42) running parallel to the through opening (31, 32), in particular in that the tap element (27) has at least one bypass path (41, 42) running parallel to the through opening (31, 32), wherein the at least one bypass path (41, 42) branches off from the through opening (31, 32).

8. Switching valve as in any one of the preceding claims, characterized in that the valve body (28) has at least one connecting line (44, 45) which, in one of the switching positions (S1, S2), connects the respective through opening (31, 32) at both ends thereof.

9. Switching valve as in claims 7 and 8, characterized in that in each of the switching positions (S1, S2) one of the connecting lines (44, 45) is connected to the respective through line (31, 32) and the appurtenant bypass path (41, 42) is connected to the other of the connecting lines (45, 44).

10. Switching valve as in claim 8 or 9, characterized in that at least one throttling device (60) is arranged in one of the connecting lines (44, 45).

11. Switching valve as in any one of claims 8 to 10, characterized in that at least one check valve (22, 23) is arranged in one of the connecting lines (44, 45), in particular at least one check valve (22, 23) is arranged in one of the connecting lines (44, 45), which check valve is flow-through in the direction of a hydraulic connection (52, 54).

12. Switching valve as in claim 11, characterized in that a stroke limiting means (62) for the non-return valve (22, 23) is arranged in the valve body (28).

13. Switching valve as in any of claims 5 to 12, characterized in that the connecting section (46) is arranged between the hydraulic connection (54) and a tap element (27) in which a throttle device (58) is arranged.

14. Switching valve as in any claim from 5 to 13, characterized in that at least one throttling device (60) is arranged upstream of the non-return valve (22) in the one connecting line (44).

15. Switching valve as in any one of the preceding claims, characterized in that the valve body (28) has a supply connection (56) which is common for both switching positions (S1, S2).

16. Switching valve as in any one of the preceding claims, characterized in that in both switching positions (S1, S2) both connecting lines (44, 45) are fluidly connected.

17. Switching valve according to one of the preceding claims, characterized in that the tap-off element (27) has a stop element (50) with which an axial movement of the tap-off element (27) in the valve body (28) can be limited, in particular in that the tap-off element (27) has a stop element (50) with which an axial movement of the tap-off element (27) in the valve body (28) can be limited and in that the stop element (50) can be brought into a latching position in the valve body (28) by means of a spring (39) in the tap-off element (27).

18. Switching valve as in any claim hereinbefore, characterized in that the valve body (28) has a recess (40) provided for interacting with a latching element (37) for axially fixing the valve body (28) in the connecting rod (1).

19. A connecting rod (1) for an internal combustion engine having a variable compression ratio, having an eccentric adjustment device (2) for adjusting the effective connecting rod length, characterized in that the adjustment path of the eccentric adjustment device (2) is adjustable by means of a switching valve (5) according to one of the preceding claims.

20. A connecting rod according to claim 19, characterized in that the eccentric adjustment device (2) has at least one and preferably two cylinders (12, 13) each having a piston (6, 7) which is guided movably in a cylinder bore (10, 11) and is connected to a support rod (8, 9), and in that an inlet is provided for the input of hydraulic liquid into the cylinders (12, 13) and an outlet is provided for the output of hydraulic liquid from the cylinders (12, 13).

21. A connecting rod according to any one of claims 19-20, characterized in that the outlet of the first cylinder (11) is connected to a hydraulic liquid circuit via the tap element (27) in the first switching position (S1), and the outlet of the second cylinder (12) is connected to the hydraulic liquid circuit via the tap element in the second switching position (S2).

22. A connecting rod according to any one of claims 19 to 21, characterized in that a first groove (25) is provided at least on a part of the circumference of the stroke bearing bore (20) for hydraulically connecting the switching valve (5) with the hydraulic liquid circuit for supplying hydraulic liquid from the hydraulic liquid circuit to the inlet opening into the cylinder (12, 13).

23. A connecting rod according to any one of claims 19 to 22, characterized in that a first groove (25) is provided at least on a part of the circumference of the stroke bearing bore (20) for hydraulically connecting the switching valve (5) with the hydraulic liquid circuit for supplying hydraulic liquid from the hydraulic liquid circuit via a common supply line (34) to the inlets into the cylinders (12, 13).

24. The connecting rod according to one of claims 19 to 23, characterized in that a filter element (26) is arranged in the connection bore (36) between the recess (24) and the switching valve (5), in particular a filter element (26) is arranged in the connection bore (36) between the recess (24) and the switching valve (5), which filter element is held captive by the switching valve (5).

25. A connecting rod according to any one of claims 19 to 24, characterized in that a latching element (37) is arranged in the connecting rod cap (24), which latching element engages into a recess (40) of the valve body (28) and axially fixes the valve body in the connecting rod cap (24).