CN113383153A

CN113383153A - System and method for adjusting the effective length of a connecting rod with lubricant supply

Info

Publication number: CN113383153A
Application number: CN201980089640.5A
Authority: CN
Inventors: 马丁·拉斯
Original assignee: AVL List GmbH
Current assignee: AVL List GmbH
Priority date: 2018-12-04
Filing date: 2019-12-04
Publication date: 2021-09-10
Also published as: WO2020113252A1; AT521887A1; AT521887B1; DE112019006024A5

Abstract

The invention discloses a system (100) and a method (110) for adjusting the effective length of a length-adjustable connecting rod (1) of an internal combustion engine, and an internal combustion engine with a length-adjustable connecting rod (1) and the system (100). The connecting rod (1) has at least one first connecting rod part (4) and a second connecting rod part (5), which are moved relative to one another and/or into one another by means of a length adjustment device (16) in the direction of a longitudinal axis (1a) of the connecting rod parts (4, 5). A lubricant supply device (101) is provided, by means of which a crankshaft bearing (K) and/or a crank pin bearing (3c) of the internal combustion engine can be acted upon with lubricant, and a hydraulic supply line (13) is provided, by means of which a length adjustment device (16) can be acted upon with lubricant serving as a hydraulic medium. Furthermore, a supply device (37) is provided, which can be in flow communication on the output side both with the lubricant supply device (101) and with the hydraulic supply line (13) and is provided for extracting lubricant from the lubricant reservoir (38) and for selectively introducing a first part of the extracted lubricant for lubricating the at least one crankshaft bearing (K) and/or crank pin bearing (3c) into the lubricant supply device (101) and a second part of the extracted lubricant for moving the two rod parts (4, 5) relative to one another and/or into one another into the hydraulic supply line (13).

Description

System and method for adjusting the effective length of a connecting rod with lubricant supply

Technical Field

The invention relates to a system and a method for adjusting the effective length of a length-adjustable connecting rod of an internal combustion engine, in particular of a reciprocating piston engine, and an internal combustion engine having a length-adjustable connecting rod and such a system.

Background

In order to optimize internal combustion engines with regard to emissions and consumption, variants with variable compression ratios are increasingly being investigated. Full load operation with a smaller compression ratio, part load operation with a higher compression ratio and start-up are possible by varying the compression of the engine. Here, consumption is improved in the partial load range, compression pressure is increased as the compression ratio is increased at start-up and peak pressure is reduced as the compression ratio is decreased at high power, and knocking is prevented.

In this connection, a length-adjustable connecting rod for an internal combustion engine is known, for example, from AT 511803B 1, which has two connecting rod parts that can be moved telescopically into one another, wherein a high-pressure chamber, into which a first oil duct opens, is spanned between the first and the second connecting rod part.

Disclosure of Invention

It is an object of the present invention to provide an improved system and method for adjusting the effective length of an adjustable length connecting rod and a corresponding internal combustion engine. The object of the invention is, in particular, to simplify the hydraulic actuation of the length adjustment device.

This object is achieved by a system and a method for adjusting the effective length of a length-adjustable connecting rod of an internal combustion engine, in particular of a reciprocating piston engine, as well as an internal combustion engine with a length-adjustable connecting rod and such a system.

A first aspect of the invention relates to a system for adjusting the effective length of a length-adjustable connecting rod of an internal combustion engine, in particular of a reciprocating piston engine, wherein the connecting rod has at least a first rod part and a second rod part. The two rod parts are preferably moved, in particular telescopically, relative to one another and/or into one another in the direction of the longitudinal axis of the rod parts by means of a length adjustment device which can be actuated, in particular hydraulically. In this case, a lubricant supply device, by means of which at least one crankshaft bearing and/or crank pin bearing of the internal combustion engine can be acted upon with lubricant, and a hydraulic supply line, by means of which the length adjustment device can be acted upon with lubricant serving as a hydraulic medium, are preferably provided. Furthermore, a supply device can be provided which can be connected on the output side both in flow communication with the lubricant supply device and in flow communication with the hydraulic supply line. The supply device is preferably provided for extracting lubricant from the lubricant reservoir on the input side and for selectively introducing a first part of the extracted lubricant for lubricating the at least one crankshaft bearing and/or crankpin bearing into the lubricant supply device and a second part of the extracted lubricant for moving the two connecting rod parts relative to one another and/or into one another into the hydraulic supply line. The lubricant may be, for example, engine oil.

In particular, the second connecting rod part with a large connecting rod opening for connection to the crankshaft and the first connecting rod part with a small connecting rod opening for connection to the piston preferably form a first hydraulic chamber which is filled to the greatest extent (i.e. completely) with hydraulic medium in a first, in particular long, switching position of the connecting rod and a second hydraulic chamber which is filled to the greatest extent (i.e. completely) with hydraulic medium in a second, in particular short, position. The first and second hydraulic chambers can preferably be selectively loaded with hydraulic medium via the hydraulic supply lines. The supply device is provided in particular for introducing a hydraulic medium into the hydraulic supply line in order to shift the connecting rod from the first switching position into the second switching position and/or to maintain the second switching position.

The effective length of the length-adjustable connecting rod is, according to the invention, in particular the distance between the axis of rotational symmetry of the small connecting rod bore for connection to the piston and the axis of rotational symmetry of the large connecting rod bore for connection to the crankshaft.

The longitudinal axis of the rod part according to the invention relates in particular to the longitudinal axis of the length-adjustable connecting rod.

The invention is based in particular on the realization that lubricant is taken from a conventional lubricant reservoir, for example by means of a pump, and then, in particular, selectively introduced into a lubricant supply for lubricating at least one crankshaft bearing and/or crankpin bearing and/or into a hydraulic supply line for moving two rod parts of a length-adjustable connecting rod relative to one another and/or into one another. For this purpose, a supply device is provided, which is preferably provided for distributing the extracted lubricant between the lubricant supply device, for example the main oil gallery, and the hydraulic supply line. The supply device can be designed, for example, as a flow divider (mengneiler) or have such a flow divider and/or be provided for adjusting the amount of lubricant introduced into the lubricant supply device and the hydraulic supply line, preferably individually or independently of one another. The supply device can be provided in particular to adjust, in particular increase or decrease, the flow of lubricant in or to the hydraulic supply line in such a way that a pressure increase or a pressure decrease is achieved which is required for switching between the first switching position and the second switching position.

The invention therefore allows the integration of a length adjustment device that can be actuated hydraulically by means of lubricating oil into the lubricant supply of an internal combustion engine. By distributing the extracted large amount of lubricant, for example pumped from a lubricant reservoir, between the lubricant supply and the hydraulic supply line, the number of components required for supplying the length adjustment device with lubricant used as hydraulic medium may advantageously be reduced. The supply device in particular allows only a single pump, for example a conventional engine oil pump, to be provided for pumping lubricant from the lubricant reservoir both into the lubricant supply device and into the hydraulic supply line. It is thus possible to dispense with an (electrical) auxiliary pump, which is provided in conventional systems for regulating the pressure in the hydraulic supply line for actuating the length adjustment device. This not only reduces the space requirement of the system, but also increases the efficiency of the internal combustion engine equipped with said system, since the friction generated by the auxiliary pump is eliminated. And thus the cost of such a system. Last but not least, this also reduces the cost of the system

The present invention generally allows for providing an improved system and method for adjusting the effective length of an adjustable length connecting rod and a corresponding internal combustion engine. In particular, the integration of the length adjustment device, which can be actuated in particular hydraulically, into the lubricant supply of the internal combustion engine can be improved, in particular simplified, by the invention.

Preferred embodiments of the invention and their extended designs are described next, which can each be combined arbitrarily with one another and with further described aspects of the invention, if this is not explicitly excluded.

In a preferred embodiment, the supply device has a pump which is provided for extracting lubricant from the lubricant reservoir and in particular for applying the second portion of lubricant at the output pressure in order in particular to move the two connecting rod parts relative to one another and/or into one another. The pump can in particular be provided for increasing or decreasing the delivery of lubricant from the lubricant reservoir for moving the two connecting rod parts relative to one another and/or into one another. In other words, the pump is preferably provided for adjusting the delivery volume for actuating the length adjustment device. The (output) pressure required for actuating the length adjustment device, in particular the pressure level in the hydraulic supply line, can thus be adjusted in a simple manner.

Here, a pump, for example a conventional engine oil pump, which is usually provided in a vehicle with an internal combustion engine, can preferably be controlled, for example by means of an Engine Controller (ECU), in order to adjust the pressure level required for actuating the length adjustment device.

In another preferred embodiment, the pump has: a first pumping device, which can be in flow communication with the lubricant supply, in particular on the output side; a second pumping device, which is in particular flow-connectable on the output side to the hydraulic supply line; and a common driver for driving the first pumping means and the second pumping means. In this case, each of the two pumping devices can preferably be controlled individually, for example by means of an engine control unit. In this way, two outputs of the supply device can be separately adjusted with respect to the lubricant portion introduced into the lubricant supply device or into the hydraulic supply line, for example, without requiring additional installation space for the other drive. The lubricant, in particular the pressure of the lubricant in the lubricant supply or hydraulic supply line, which is drawn off from the lubricant reservoir, can thus be metered particularly precisely and independently of the distribution into the lubricant supply or hydraulic supply line.

The first and second pumping devices may have, for example, a rotor arranged eccentrically to the stator of a rotary slide valve pump or a vane pump. The rotary slide valve pump or vane pump is preferably designed such that the eccentricity of the rotor of the first pumping device and the rotor of the second pumping device can be adjusted separately, so that two different volume flows can be achieved on the output side of the two pumping devices.

In a further preferred embodiment, the supply device has a distributor device, which is arranged in particular downstream of the pump and which is provided for, in particular actively, for example as a function of the output pressure, adjusting the flow rate of the lubricant, which is applied at the output pressure, into the lubricant supply device and/or the flow rate of the hydraulic medium, which is used to move the two connecting rod parts relative to one another and/or into one another, into the hydraulic supply line. The distributor device can in particular adjust the ratio between the flow into the lubricant supply and the flow into the hydraulic supply line. In other words, the distributor device can divide the lubricant, which is extracted from the lubricant reservoir, for example pumped by means of a pump, and is loaded at the output pressure, into a first portion and a second portion, for example in order to set the pressure level in the lubricant supply device or the hydraulic supply line. The distribution of lubricant between the lubricant supply and the hydraulic supply line can thereby be carried out particularly effectively.

The flow rate of the lubricant is, according to the invention, in particular the quantity of lubricant flowing through a section of the lubricant supply or hydraulic supply line per unit time. The increase in the flow into the hydraulic supply line preferably corresponds here to an increase in the output pressure.

The distributor device can preferably be controlled, for example by an engine controller, in order to regulate the flow of lubricant, in particular into the lubricant supply and/or the hydraulic supply line.

The distributor device may, for example, be provided for controlling the flow of lubricant into the lubricant supply in such a way that a sufficient amount of lubricant is provided in the crankshaft bearing and/or the crank pin bearing. The distributor device can be responsible, in particular, for keeping the flow rate to the lubricant supply constant, independently of the delivery pressure.

Alternatively or additionally, a distributor device may be provided for controlling the flow of lubricant into the hydraulic supply line in such a way that a greater portion of lubricant is introduced into the hydraulic supply line when the output pressure increases and a smaller portion of lubricant is introduced into the hydraulic supply line when the output pressure decreases. The length adjustment device can thereby be actuated reliably.

In a further preferred embodiment, the distributor device has a first flow valve associated with the lubricant supply device and a second flow valve associated with the hydraulic supply line. The flow valve can be designed in particular as a throttle valve, an orifice throttle valve and/or the like. The delivery of lubricant into the lubricant supply or into the hydraulic supply line can thereby be reliably controlled. For example, the pressure of the lubricant in the lubricant supply can be reduced to a desired or predetermined pressure level by suppressing the output pressure by means of the first flow valve, while in the hydraulic supply line the pressure increase is achieved, in particular, by a corresponding configuration of the second flow valve.

In a further preferred embodiment, the hydraulic supply line has at least one supply line channel, wherein the at least one crankshaft bearing and the at least one crankpin bearing are preferably in flow communication via the supply line channel. The hydraulic supply line preferably has at least one supply line channel which extends in the crankshaft from at least one crankshaft bearing to the crankpin bearing, where the length adjustment device can be actuated by means of a lubricant which serves as a hydraulic medium and is optionally pressurized.

In another preferred embodiment, the hydraulic supply line is in flow communication with at least one crankshaft bearing for feeding the length adjustment device. The lubrication of the at least one crankshaft bearing and/or the crankpin bearing can be achieved in a particularly simple manner by the supply of the at least one crankshaft bearing.

In another preferred embodiment, both the hydraulic supply line and the lubricant supply are preferably in flow communication with at least one crankshaft bearing through an inlet opening of the crankshaft bearing. At least one crankshaft bearing preferably has an inlet opening through which lubricant supplied by the lubricant supply and the hydraulic supply line can enter the crankshaft bearing. At least one crankshaft bearing is thus supplied with lubricant via the two feed structures, i.e. via the lubricant supply and the hydraulic supply line. An advantage of this embodiment is that by introducing lubricant to the lubrication point, i.e. the crankshaft bearing, by means of the lubricant supply and the hydraulic supply line, a change in the pressure level of the lubricant can be facilitated in a particularly simple manner in order to actuate the length adjustment device.

The lubricant supply preferably has at least one non-return valve which is provided, in particular so arranged, to prevent lubricant which is introduced into the at least one crankshaft bearing via the hydraulic supply line from flowing out into the lubricant supply. In this case, a pressure drop in the hydraulic supply line or in the crankpin bearing, which would make it impossible or at least difficult to reliably actuate the length adjustment device, can be avoided by means of the at least one check valve.

In another preferred embodiment, the lubricant supply is in flow communication with the first set of crankshaft bearings. The hydraulic supply line for feeding the length adjustment device is preferably in flow communication with the second group of crankshaft bearings, wherein the first group does not contain the crankshaft bearings of the second group and the supply device is provided for lubricating the second group of crankshaft bearings with lubricant via the hydraulic supply line in addition to lubricating the first group of crankshaft bearings with lubricant via the lubricant supply device. The structure of the lubricant supply device is thus simplified, since the oil supply line to the second set of crankshaft bearings can be dispensed with.

The supply device is preferably provided here for introducing a portion of the lubricant, which is extracted from the lubricant reservoir, into the hydraulic supply line independently of the switching state of the connecting rod, in order to be able to ensure the lubrication of the second group of crankshaft bearings.

A second aspect of the invention relates to a method for adjusting the effective length of a length-adjustable connecting rod of an internal combustion engine, in particular of a reciprocating piston engine, wherein the connecting rod has at least a first rod part and a second rod part. The two rod parts are preferably moved relative to one another and/or into one another, in particular telescopically, in the direction of the longitudinal axis of the rod part by means of a length adjustment device, which can be actuated in particular hydraulically. Within the scope of the method, the lubricant is preferably taken from the lubricant reservoir by means of a supply device, wherein the supply device can be brought into flow communication on the output side both with the lubricant supply device and with a hydraulic supply line, wherein at least one crankshaft bearing and/or crank pin bearing of the internal combustion engine can be acted upon with lubricant by means of the lubricant supply device, and the length adjustment device can be acted upon with lubricant serving as a hydraulic medium by means of the hydraulic supply line. A first portion of the extracted lubricant for lubricating at least one crankshaft bearing and/or crank pin bearing can be conducted into the lubricant supply, and a second portion of the extracted lubricant for moving the two connecting rod parts relative to each other and/or into each other can be conducted into the hydraulic supply line.

A third aspect of the invention relates to an internal combustion engine, in particular a reciprocating piston engine, with: a length-adjustable connecting rod having at least one first and one second connecting rod part, wherein the two connecting rod parts can be moved, in particular telescopically, relative to one another and/or into one another in the direction of the longitudinal axis of the connecting rod parts by means of a length-adjusting device, which can be actuated, in particular hydraulically; and a system according to the first aspect of the invention.

The features and advantages described with reference to the first aspect of the invention and its advantageous embodiments also apply, at least where technically reasonable, to the second and third aspects of the invention and its advantageous embodiments and vice versa.

Drawings

The invention will be explained in more detail below with the aid of non-limiting embodiments shown in the drawings. In the figure:

FIG. 1 shows, at least partially schematically, a longitudinal section through a preferred embodiment of a length-adjustable connecting rod;

fig. 2a shows at least partially schematically a preferred embodiment of a length adjustment device for a length-adjustable connecting rod in a first switching position;

fig. 2b shows at least partly schematically the length adjustment device of fig. 2a in a second switching position;

fig. 3 shows a schematic representation of a system according to the invention according to a first preferred embodiment;

fig. 4 shows a schematic representation of a system according to the invention according to a second preferred embodiment; and is

Fig. 5 shows a preferred embodiment of the method according to the invention at least partially schematically.

Detailed Description

Fig. 1 shows a length-adjustable connecting rod 1 for a reciprocating piston engine, for example an internal combustion engine, with a small connecting rod bore 2 for a piston pin bearing, not shown in detail, and a large connecting rod bore 3 for a crank pin bearing, not shown in detail, of the internal combustion engine. The axis of rotational symmetry of the small or large connecting rod bores 2, 3 is marked with the reference numeral 2a or 3 a. The longitudinal axis of the connecting rod 1 is designated by the reference numeral 1a, and the longitudinal center plane, i.e. the pivot plane, which is perpendicular to the rotational symmetry axes 2a and 3a of the connecting rod 1 with the small and large connecting rod bores 2, 3 and contains the longitudinal axis 1a of the connecting rod 1, is designated by the reference numeral epsilon.

The connecting rod 1 has an upper first rod part 4 with a small connecting rod bore 2 and a lower second rod part 5 with a large connecting rod bore 3. The first lever part 4 can be adjusted relative to the second lever part 5 by an adjustment range Δ L in the direction of the longitudinal axis 1a of the connecting rod 1 between a first switching position corresponding to the extended position and a second switching position corresponding to the insertion position shown in fig. 1. In the upper shaft part 4, a substantially cylindrical piston element 6 is fixed, for example, with a fastening screw 7 formed by a socket head cap screw.

The piston element 6 is guided in an axially displaceable manner in a guide cylinder 8 of the lower second rod part 5 of the connecting rod 1, wherein a first hydraulic chamber 9 is opened between a first end face 6a of the piston element 6 facing the large connecting rod bore 3 and the second rod part 5 in at least one position of the two

rod parts

4, 5. The piston element 6, which is designed as a multistage piston, has a second end face 6b facing the small connecting rod bore 2, which second end face adjoins a second hydraulic chamber 10, the cylindrical lateral surface of which is formed by the guide cylinder 8 of the second connecting rod section 5. A multistage piston generally refers to a piston having differently large active surfaces, in the present case a "piston acting on both sides", wherein one of the active surfaces (here: the active surface oriented toward the second hydraulic chamber 10) is configured as an annular surface and the other active surface is configured as a circular surface. Different pressure ratios can be achieved by different active surfaces.

The first and second end faces 6a, 6b form pressure running faces for a pressurized hydraulic medium, such as engine oil or other lubricant, which is introduced into the

hydraulic chambers

9, 10.

The first oil channel 11 opens into the first hydraulic chamber 9 and the second oil channel 12 opens into the second hydraulic chamber 10, through which lubricant can be supplied/discharged.

The oil supply of the first and

second oil channels

11, 12 is effected via a hydraulic supply line 13, which originates from the connecting rod bearing 3b of the large connecting rod bore 3 and is therefore in flow communication with a crank pin bearing, not shown in detail, and via connecting

channels

14, 15 connected to the hydraulic supply line 13.

In order to control the pressure in the first and second

hydraulic chambers

9, 10, a length adjustment device 16 is provided in the connecting rod 1, more precisely in the lower second connecting rod section 5, which length adjustment device has, in the flow path between the first connecting duct 14 and the first oil duct 11, a first valve 17 with a first valve chamber 18 in which a first valve body 20, which is prestressed by a first valve spring 19, is pressed against a first valve seat 21. The first oil passage 11 opens into the first valve chamber 18. The length adjustment device 16 also has a second valve 22 with a second valve chamber 23, in which a second valve body 25, which is prestressed by a second valve spring 24, is pressed against a second valve seat 26, wherein the second oil channel 12 opens into the second valve chamber 23. Furthermore, the length adjustment device 16 has a connecting device 27 between the first valve 17 and the second valve 22 with at least one connecting element 28, which in the exemplary embodiment is formed by a connecting rod 29 perpendicular to the longitudinal axis 1a, in particular arranged in the longitudinal center plane epsilon of the connecting rod 1. The connecting element 28 is firmly connected with a control piston 31 which is movable in a control cylinder 30. A spring-loaded control piston 31 adjoins a control chamber 33 into which a control line 34 connected to the hydraulic supply line 13 or to the connecting channel 15 opens, via a return spring 32. The

valve body

20 or 25 and the connecting means 27 are separate components. The connecting device 27 is therefore spaced apart from the second valve body 25 in at least one first displacement position of the connecting element 28, which is shown in fig. 2a, and from the first valve body 20 in a second displacement position, which is shown in fig. 2 b.

The first and

second valve bodies

20, 25 of the first and second valves 17, 22 are preferably formed by spheres.

The flow communication between the first inlet channel 14 and the first oil channel 11 or between the second inlet channel 15 and the second oil channel 12 is opened or closed by the

valve bodies

20, 25 of the first and second valves 17, 22. The control piston 31, for example made of plastic, is actuated by the output pressure in the hydraulic supply line 13, for example the oil pressure of the internal combustion engine.

When the oil pressure is kept at a defined response pressure (e.g. 1.8bar), for example at light loads, the control piston 31 remains in its second position shown in fig. 2b, since the spring force of the return spring 32 is a force which is greater than the oil pressure in the control line 34, which acts on the end face of the control piston 31. In this case, the connecting rod 29, which is firmly connected to the control piston 31, for example by press fitting, keeps the valve body 25 open for connection to the second hydraulic chamber 10 via the second oil passage 12, while the valve body 20 of the first valve 17 is kept closed for connection to the first hydraulic chamber 9 by the first valve spring 19.

During the stroke movement, in the region of the upper dead center of the piston, not shown in detail, an inertial force acts on the connecting rod 1, which pulls the first connecting rod part together with the piston 6 (as viewed in fig. 1, 2a and 2b) and thus the small bore upward. In this case, oil is sucked in through the initially closed first valve 21 in such a way that the first valve body 20 is lifted by the suction effect occurring in the first hydraulic chamber 9 counter to the restoring force of the first valve spring 19; the lower first hydraulic chamber 9 is filled with oil via a first oil channel 11, and the oil is pressed from the upper second hydraulic chamber 10 into a second oil channel 12. The connecting rod 1 is thus lengthened. The oil flow in the

oil channels

11, 12 is shown by arrows in fig. 2 b.

When the oil pressure rises to a higher level at higher engine loads, the return spring 32 of the control piston 31 is compressed, wherein the control piston 31 moves to the left stop of the control cylinder 30.

In this position, the connecting rod 29 presses the first valve body 20 of the first valve 17, which connects the first hydraulic chamber 9 with the oil supply passage 13. The oil can therefore flow from the first hydraulic chamber 9 back into the hydraulic supply line 13 and thus further back into the oil supply system. Since the connecting rod 29 is lifted from the second valve body 25 and the second valve body is thus pressed against the second valve seat 26 by the restoring force of the second valve spring 24, the second valve 22 is closed; at each ignition, the piston 6 is pressed downward and oil is sucked into the second hydraulic chamber 10 by the second valve body 25, which is lifted up against the force of the second valve spring 24, via the second valve 22, which is closed as a result of the suction effect in the second hydraulic chamber 10, until the second hydraulic chamber 10 is filled with oil. The flow of oil is shown by the arrows in figure 2 a. In this position, the link 1 is shortened.

When the oil pressure in the oil system or lubricant system drops again, the return spring 32 (fig. 2b) of the control piston 31 expands and the control piston 31 moves to the right as viewed in fig. 2b, wherein the second valve 22 for the second hydraulic chamber 10 is opened and the first valve 17 for the first hydraulic chamber 9 is closed. The first hydraulic chamber 9 is again inflated by the inertial forces acting on the second rod part and the piston element 6 in the upper dead centre of the piston in the manner described and the connecting rod 1 lengthens again.

Fig. 3 shows a system 100 according to the invention according to a first preferred embodiment. The lubricant supply 101 is provided for supplying a crankshaft bearing K of the crankshaft 50 with a lubricant, for example oil, such as engine oil. For this purpose, the lubricant supply 101 has a main oil line 102, from which an oil supply line 102a to the crankshaft bearing K branches off. The crankshaft bearings K each have an inlet opening through which the lubricant for lubrication, which is supplied by the lubricant supply 101 and/or the hydraulic supply line 13, enters the crankshaft bearings K. The crank pin bearing 3c of the crankshaft 50 is in flow communication with the crankshaft bearing K via a supply line channel 104 extending in the crankshaft 50 and shown in dashed lines, whereby the crank pin bearing 3c may also be supplied with lubricant. In such an oil-lubricated crankpin bearing 3c of the crankshaft 50, a correspondingly length-adjustable connecting rod (see fig. 1) is pivotably supported by means of a large connecting rod bore.

As explained in detail in connection with fig. 1, the length, in particular the effective length, of the length-adjustable connecting rod can be adjusted by means of the oil pressure in the crank pin bearing 3c, by means of which the length adjustment device in the connecting rod (see fig. 1, 2a and 2b) can be actuated and thus the first and second hydraulic chambers in the connecting rod can be selectively charged with oil. For this purpose, a hydraulic supply line 13 is provided which supplies lubricant at a pressure or pressure level which is lower than the pressure or pressure level required for actuating the length adjustment device as a hydraulic medium, with which the crankshaft bearing K and the crank pin bearing 3c can be lubricated.

In order to prevent the lubricant introduced into the two crankshaft bearings K through the hydraulic supply line 13 from flowing out into the oil supply line 10a at the pressure required for actuating the length adjustment device and the pressure in the crank pin bearing 3c thus dropping, a check valve 103 is provided in the oil supply line 102a which leads into the two crankshaft bearings K and is also in flow communication with the hydraulic supply line 13.

It is also conceivable to dispense with two oil supply lines 102a in which a check valve 103 is arranged and which open into two crankshaft bearings K, with which the hydraulic supply line 13 is in flow communication. In this case, the remaining oil supply line 102a opens into a first group of crankshaft bearings K and the hydraulic supply line 13 is in flow communication with a second group of crankshaft bearings K, wherein the two groups do not have a common crankshaft bearing K. It should be ensured here that a lubricant serving as a hydraulic medium is provided via the hydraulic supply line 13 not only for actuating the length adjustment device, but also for lubricating the crankshaft bearing K and the crank pin bearing 3 c.

The lubricant or hydraulic medium can be taken from a lubricant reservoir 38 by means of a supply device 37, to which the supply device 37 can be brought into flow communication on its input side. The lubricant reservoir 38 is preferably a conventional engine oil sump. The supply 37 is furthermore preferably provided for distributing the lubricant extracted from the lubricant reservoir 38 between the lubricant supply 101 and the hydraulic supply line 13 in such a way that a first part of the extracted lubricant is conducted into the lubricant supply 101, in particular the main oil line 102, and a second part of the extracted lubricant is conducted into the hydraulic supply line 13.

For this purpose, the supply device 37 preferably has a pump 35 which sucks lubricant on the input side in a lubricant reservoir 38 and/or applies lubricant at an output pressure on the output side. The lubricant pressure, in particular the oil pressure, in the lubricant reservoir 38 is essentially dependent on the rotational speed of the internal combustion engine or of the crankshaft 50. The pump 35 can therefore be provided in particular to generate an output pressure independently of the lubricant pressure or engine oil pressure prevailing in the lubricant reservoir 38. The pump 35 is preferably provided for loading the lubricant at an output pressure which is higher than the lubricant pressure or the engine oil pressure in the lubricant reservoir 38.

Furthermore, the supply device 37 has a distributor device 39, which is provided to regulate the flow of lubricant, in particular pressurized with the delivery pressure, into the lubricant supply 101 and/or into the hydraulic supply line 13. As shown in fig. 3, the distributor device 39 can have a respective

adjustable flow valve

39a, 39b for this purpose, with which the delivery quantity of the lubricant introduced into the lubricant supply 101 or into the hydraulic supply line 13 and thus the pressure in the lubricant supply 101 or in the hydraulic supply line 13 can be adjusted. The

flow valves

39a, 39b can be configured, for example, as throttle valves. However, it is also conceivable to provide orifice throttles instead of the

flow valves

39a, 39 b. Alternatively, distributor device 36 may be configured as a geared flow divider.

The supply device 37 may preferably be controlled by a control device 36, such as an Engine Controller (ECU), in particular in order to regulate a first portion of lubricant drawn from the lubricant reservoir 38 into the lubricant supply device 101 and/or a second portion of lubricant drawn from the lubricant reservoir 38 into the hydraulic supply line 13. If the rotational speed of the internal combustion engine or the crankshaft 50 is increased, for example, and the lubricant pressure in the lubricant reservoir 38 is increased as a result, the pumping power of the pump 35 may be reduced, for example, in order to ensure a constant output pressure in the lubricant supply 101 and/or in the hydraulic supply line 13. Conversely, if the pressure in the hydraulic supply line 13 for actuating the length adjustment device should be increased, for example to a predetermined pressure level or to a pressure level exceeding a predetermined pressure level, the pump 35 can be caused to generate a higher output pressure, the first flow valve 39a reduces the lubricant flow in the lubricant supply 101 and the first flow valve 39b increases the lubricant flow in the hydraulic supply line 13, for example. In this way, the pressure in the lubricant supply 101 can be kept constant, although a higher output pressure is generated by the pump 35 to actuate the length adjustment device.

The lubricant introduced into the hydraulic pressure supply line 13 may be stored in the accumulator 40. In particular the electronically controllable 2/2 directional control valve 41 can establish or interrupt the flow communication between the accumulator 40 and the hydraulic supply line 13 when required. The hydraulic check valve 42 is provided to prevent a pressure drop in the hydraulic supply line 13 even if the supply device 37 is not introducing lubricant into the hydraulic supply line 13, in particular the pump 35 is not operating.

Fig. 4 shows a system 100 according to the invention according to a second preferred embodiment, which differs from the embodiment shown in fig. 3 by the design of the supply device 37. The supply device 37 has a pump 35 with two

pumping devices

35a, 35b, wherein the first pumping device 35a is associated with the lubricant supply 101, in particular can be in flow communication with this lubricant supply on the output side, and the second pumping device 35b is associated with the hydraulic supply line 13, in particular can be in flow communication with this hydraulic supply line on the output side.

The pump 35 has a single, in particular electrical or mechanical, drive 35c, which drives the two

pumping devices

35a, 35b synchronously. The drive 35c is preferably arranged here, in particular together with the two

pumping devices

35a, 35b, in a common housing 35 d.

The pump 35 can be configured, for example, as a rotary slide valve pump with two rotors or as a vane pump. The two rotors are here part of one each of the two

pumping devices

35a, 35 b. Furthermore, the

pumping devices

35a, 35b preferably also have means in order to adjust the eccentricity of the respective rotor about the common drive axis and thus the flow rate or delivery of lubricant delivered by the

respective pumping device

35a, 35 b.

In order to increase or decrease the first portion of lubricant extracted from the lubricant reservoir 38 and introduced into the lubricant supply 101, the eccentricity of the rotor of the first pumping device 35a can be adjusted accordingly, for example by means of the control device 36. If, on the other hand, the second portion of lubricant drawn from the lubricant reservoir 38 and introduced into the hydraulic supply line 13 should be increased or decreased, the eccentricity of the rotor of the second pumping device 35b can be adjusted accordingly by means of the control device 36. The supply device 37 thus provides two volume flows of lubricant on the output side, in particular independently of one another, and in particular regulates the pressure in the lubricant supply 101 and/or the pressure in the hydraulic supply line 13.

Fig. 5 shows a preferred embodiment of a method 110 according to the invention for adjusting the effective length of a length-adjustable connecting rod of an internal combustion engine, wherein the connecting rod has at least one first connecting rod section, a second connecting rod section and a length adjustment device for displacing the first connecting rod section relative to the second connecting rod section in such a way that, in a first switching position of the length adjustment device, a first hydraulic chamber formed by the first and second connecting rod sections can be filled with a hydraulic medium and, in a second switching position of the length adjustment device, a second hydraulic chamber formed by the first and second connecting rod sections can be filled with a hydraulic medium. The connecting rod is in this case in the long first switching position when the first hydraulic chamber is filled to the maximum with hydraulic medium, for example, by means of an inertial force acting on the connecting rod during a stroke. In contrast, the connecting rod is in this case in the second, short switching position when the second hydraulic chamber is filled to the maximum with hydraulic medium, for example by means of an inertial force acting on the connecting rod during a stroke.

In a method step S1, lubricant, for example oil, in particular engine oil, is extracted from a lubricant reservoir, in particular from an engine oil sump of a vehicle equipped with an internal combustion engine, by means of a supply device. For this purpose, the supply device can be in flow communication with the lubricant reservoir on the input side and preferably has a pump for delivering the lubricant. The supply device is connected on the output side to a lubricant supply device, by means of which lubricant can be supplied to at least one crankshaft bearing and/or crank pin bearing of the internal combustion engine. Furthermore, the supply device is also connected on the output side to a hydraulic supply line, via which the length adjustment device can be supplied with lubricant serving as a hydraulic medium. The supply device preferably has a separate outlet for connection to a lubricant supply device or a hydraulic supply line.

In a further method step S2, the first portion of the extracted lubricant for lubricating the first crankshaft bearing and/or the crank pin bearing is introduced into a lubricant supply. For this purpose, the supply device has, for example, a distributor device, by means of which the first portion of lubricant can be adjusted.

The extracted second portion of lubricant is introduced into the hydraulic supply line in a further method step S3 in order to move the two connecting rod parts relative to one another and/or into one another, that is to say in order to actuate the length adjustment device. The second portion of lubricant can preferably also be adjusted by means of the dispenser device.

Even though the method steps S1, S2, S3 are shown in the form of a flow chart in the present fig. 5, it is clear to the person skilled in the art that the method steps S1, S2, S3 are preferably carried out substantially synchronously. In other words, the supply device conveys lubricant from the lubricant reservoir directly into the lubricant supply device and/or into the hydraulic supply line, in particular when at least one crankshaft bearing and/or crankpin bearing should be lubricated and/or the length adjustment device should be actuated.

List of reference numerals

1 connecting rod with adjustable length

1a longitudinal axis of the connecting rod

2 small connecting rod hole

2a small connecting rod hole rotational symmetry axis

3 big connecting rod hole

Axis of rotational symmetry of 3a large link hole

3b connecting rod bearing

3c crank pin bearing

4 first link portion

5 second connecting rod part

6 piston element

6a, 6b first and second end sides

7 fastening screw

8 guide cylinder

9 first hydraulic chamber

10 second hydraulic chamber

11 first oil passage

12 second oil passage

13 hydraulic supply line

14. 15 connecting channel

16 length adjusting device

17 first valve

18 first valve chamber

19 first valve spring

20 first valve body

21 first valve seat

22 second valve

23 second valve chamber

24 second valve spring

25 second valve body

26 second valve seat

27 connecting device

28 connecting element

29 connecting rod

30 control cylinder

31 control piston

32 return spring

33 control room

34 control line

35 Pump

35a, 35b first and second pumping means

35c driver

35d casing

36 control device

37 supply device

38 engine oil sump

39 dispenser device

39a, 39b first and second flow valves

40 pressure accumulator

412/2 change valve

42 hydraulic check valve

50 crankshaft

100 system

101 lubricant supply device

102 main oil pipeline

102a oil supply line

103 check valve

104 supply line channel

110 method

Method steps S1-S3

K crankshaft bearing

Epsilon longitudinal central plane

Delta L adjustment region

Claims

1. A system (100) for adjusting the effective length of a length-adjustable connecting rod (1) of an internal combustion engine, in particular of a reciprocating piston engine, wherein the connecting rod (1) has at least one first rod part (4) and a second rod part (5) and the two rod parts (4, 5) are moved, in particular telescopically, relative to one another and/or into one another by means of a length adjustment device (16) in the direction of a longitudinal axis (1a) of the rod parts (4, 5), having:

-a lubricant supply device (101) by means of which a crankshaft bearing (K) and/or a crank pin bearing (3c) of the internal combustion engine can be loaded with lubricant;

-a hydraulic supply line (13) through which the length adjustment device (16) can be loaded with lubricant serving as a hydraulic medium;

-a supply device (37) which can be in flow communication on the output side both with the lubricant supply device (101) and with the hydraulic supply line (13) and which is provided for extracting lubricant from the lubricant reservoir (38) and for selectively introducing a first portion of the extracted lubricant for lubricating the at least one crankshaft bearing (K) and/or crank pin bearing (3c) into the lubricant supply device (101) and a second portion of the extracted lubricant for moving the two rod parts (4, 5) relative to one another and/or into one another into the hydraulic supply line (13).

2. The system (100) as claimed in claim 1, characterized in that the supply device (37) has a pump (35) which is provided for loading the lubricant extracted from the lubricant reservoir (38), in particular the second portion of lubricant, with an output pressure.

3. The system (100) according to claim 2, wherein the pump (35) has a first pumping device (35a) which is flow-communicable with the lubricant supply (101) and a second pumping device (35b) which is flow-communicable with the hydraulic supply line (13), and a common drive (35c) for driving the first and second pumping devices (35a, 35 b).

4. A system (100) according to claim 2 or 3, characterised in that the supply device (37) has a distributor device (39) which is provided for adjusting the flow of lubricant loaded at the output pressure into the lubricant supply device (101) and/or the flow of hydraulic medium into the hydraulic supply line (13) in order to move the two connecting rod parts relative to each other and/or into each other.

5. System (100) according to claim 4, characterized in that the distributor device (39) has a first flow valve (39a) assigned to the lubricant supply device (101) and a second flow valve (39b) assigned to the hydraulic supply line (13).

6. The system (100) according to any one of the preceding claims, wherein the hydraulic supply line (13) has at least one supply line channel (104), wherein the supply line channel (104) preferably extends from the at least one crankshaft bearing (K) to the at least one crankpin bearing (3 c).

7. The system (100) according to any one of the preceding claims, wherein the hydraulic supply line (13) for supplying the length adjustment device (16) is in flow communication with the at least one crankpin bearing (K).

8. System (100) according to claim 6 or 7, characterized in that at least one crankshaft bearing (K) has an inlet opening for delivering lubricant into the inlet channel (104), wherein the inlet opening is in flow communication with both the hydraulic line (13) and the lubricant supply (101).

9. The system (100) according to any one of the preceding claims, wherein the lubricant supply (101) has at least one check valve (103) which is provided for preventing lubricant which is introduced into the at least one crankshaft bearing (K) via the hydraulic supply line (13) from flowing out into the lubricant supply (101).

10. The system (100) according to any one of claims 1 to 6, wherein the lubricant supply device (101) is in flow communication with a first set of crankshaft bearings (K) and the hydraulic supply line (13) for supplying the length adjustment device (16) is in flow communication with a second set of crankshaft bearings (K), wherein the first set of crankshaft bearings does not contain the second set of crankshaft bearings (K) and the supply device (37) is provided for lubricating the second set of crankshaft bearings (K) with lubricant also via the hydraulic supply line (13) in addition to lubricating the first set of crankshaft bearings (K) with lubricant via the lubricant supply device (101).

11. A method (110) for adjusting the effective length of a length-adjustable connecting rod (1) of an internal combustion engine, in particular of a reciprocating piston engine, wherein the connecting rod (1) has at least one first rod part (4) and a second rod part (5) and the two rod parts (4, 5) are moved, in particular telescopically, relative to one another and/or into one another by means of a length adjustment device (16) in the direction of a longitudinal axis (1a) of the rod parts (4, 5), wherein,

-lubricant is extracted from the lubricant reservoir (38) by means of a supply device (37), wherein the supply device (37) can be in flow communication on the output side both with the lubricant supply device (101) and with the hydraulic supply line (13), by means of which lubricant supply device at least one crankshaft bearing (K) and/or crank pin bearing (3c) of the internal combustion engine can be loaded with lubricant and by means of the hydraulic supply line the length adjustment device (16) can be loaded with lubricant used as hydraulic medium,

-the extracted first part of the lubricant for lubricating the at least one crankshaft bearing (K) and/or the crankpin bearing (3c) is conducted into a lubricant supply (101), and

-a second portion of the extracted lubricant for moving the two rod parts (4, 5) relative to and/or into each other is led into the hydraulic supply line (13).

12. An internal combustion engine, in particular a reciprocating piston engine, comprising: a length-adjustable connecting rod (1) having at least one first connecting rod part (4) and a second connecting rod part (5), wherein the two connecting rod parts (4, 5) are moved, in particular telescopically, relative to one another and/or into one another by means of a length adjustment device (16) in the direction of a longitudinal axis (1a) of the connecting rod parts (4, 5); and a system (100) according to any of claims 1 to 10.