Valve actuator with switching device

Abstract

The present invention relates to a valve actuation device (100) for a valve of a reciprocating piston engine, which has a coupling device (10) with a locking element (13B) that can be brought into a first position and a second position by a mechanical switching device (110). The switching device (110) comprises a guide rod (83) and a parallel actuating rod (81) which are capable of relative movement, slotted guide elements (84, 85) movably mounted on the guide rod (83) for moving the locking element (85), and a trigger element (111) connected to the slotted guide elements (84, 85), the slotted guide elements (84, 85) and the trigger element (111) being clamped between two stops (89, 89') on the actuating rod (81) and each having an associated spring element (93, 94), the slotted guide elements (84, 85) and the trigger element (111) being displaceable along and / or parallel to the guide rod (83) together with the actuating rod (81). The blocking element (112) interacts with the trigger element (111) to, in a first state, block displacement of the trigger element (111) and the slotted guide elements (84, 85) when the actuating rod (81) is axially displaced such that the spring elements (93, 94) are preloaded, and, in a second state, allow displacement of the trigger element (111) and the slotted guide elements (84, 85) resulting in actuation of the coupling device (111).

Description

[Technical Field]

[0001] The present invention relates to a valve-actuating device for actuating at least one valve of a reciprocating piston engine, in particular an internal combustion engine, the valve-actuating device comprising a mechanical coupling with a locking element that can be moved to at least a first and a second position by a switching device for actuating the coupling, the valve-actuating device transmitting an actuating movement for the at least one valve in at least the first position of the locking element. [Background technology]

[0002] Valve actuation devices in general, and combustion engines having such valve actuation devices, are generally known from the prior art.

[0003] Due to ever increasing demands regarding performance, efficiency and emissions, variable valve trains, i.e. valve trains with variable valve lift, are becoming increasingly important in reciprocating internal combustion engines, especially in four-stroke and six-stroke operation.

[0004] A variable valve train can meet the needs faced by combustion engine designers and, in particular, the thermodynamic desires of alternatively assigning different valve lift curves to one or more valves depending on the operating conditions of the combustion engine, thereby adjusting both the valve lift and the opening and closing points.

[0005] This is typically achieved by switching the transmission path of the valve train. In various applications, lift switching and lift cut-off systems with switchable cam followers such as bucket tappets, roller tappets, rocker arms, etc. are used in series. Applicable here is that for each additional alternative valve lift, a corresponding cam must also be provided as the lift providing element, unless the alternative lift is zero lift.

[0006] There are many different applications for the use of variable or variable valve lift valve trains, some examples of which are:

[0007] Lift switching: Lift switching allows the operating point-dependent use of at least two different valve lifts. Here, a smaller valve lift is used that is specifically tailored to the part-load range, improving the torque curve and reducing consumption and emissions. The larger valve lift can be optimized for further performance improvements. The smaller valve lift and shorter duration of the lower maximum lift make it possible to reduce the gas exchange work (Miller cycle) through a significantly earlier intake closure point and dethrottling of the intake system. Similar results can be achieved with the Atkinson cycle, i.e., a very late intake closure. Optimal filling of the combustion chamber thereby still results in increased torque in the part-load range.

[0008] Cylinder cut-off: Cylinder cut-off is primarily used in large-capacity four-cylinder engines (e.g., 4-, 8-, 10-, or 12-cylinder engines). It deactivates selected engine cylinders by switching off the lift at the intake and exhaust valves, thereby completely isolating them from the cam lift. By using an evenly spaced firing sequence, common V8 and V12 motors can be converted into A4 or R6 engines. The purpose of engine cylinder isolation is to minimize gas exchange losses and shift the operating point to a higher mean pressure, and therefore a higher thermodynamic efficiency, thereby allowing significant fuel savings to be achieved.

[0009] Engine braking mode: Engine braking systems that enable an engine braking mode are becoming increasingly important for vehicle combustion engines, especially commercial vehicles, because they constitute a cost-effective and space-saving additional braking system that can reduce the load on the wheel brakes, especially on long downhill slopes. Furthermore, increasing the specific power of modern commercial vehicle engines also requires an increase in the achievable braking force.

[0010] A known method for achieving an engine braking effect is to provide an additional macrovalve in the cylinder of a combustion engine, which, in particular in four-stroke or six-stroke engines, can depressurize the cylinder via the additional engine valve at the end of the compression stroke, thereby implementing so-called decompression braking. The work performed on the compressed gases is then discharged via the exhaust system of the combustion engine. Furthermore, the combustion engine must expend work to refill the cylinders with gas. It is known to generate an engine braking effect, in particular via a variable valve train of the actual exhaust valve.

[0011] Various systems and concepts for varying valve lift are known, in particular providing a mechanical or hydraulic linkage between one or more cam lift transmitting valve actuation elements of a valve actuation system, through which a switch in the valve train transmission path can be achieved.

[0012] For example, Patent Document 1 discloses a system for variable valve timing, particularly for generating an engine braking effect, which system includes a "lost motion" device with a hydraulically actuable locking element for selectively locking or unlocking a valve actuation mechanism, thereby selectively transmitting or not transmitting valve actuation motion to one or more valves to vary valve lift and thereby, particularly, generate engine braking.

[0013] Patent Document 2 discloses a valve actuation device for actuating at least a first valve of a reciprocating piston engine, particularly an internal combustion engine, which can be used particularly for engine braking, and which has a first rocker arm portion, a second rocker arm portion, and a first switching element for changing the valve lift of at least one first valve, wherein the first rocker arm portion and the second rocker arm portion are rotatably attached and arranged such that at least one first valve timing movement of a first camshaft can be transmitted to the at least one first valve via the first rocker arm portion and the second rocker arm.

[0014] Patent Document 3 relates to a valve actuation device for actuating at least one valve of a reciprocating piston engine with variable valve lift, particularly a valve actuation device for a reciprocating internal combustion engine, and a coupling device for the valve actuation device and the reciprocating piston engine. The coupling device includes a first coupling element, a second coupling element, and a locking device. The first and second coupling elements are displaceable relative to each other along a first axis at least within a predetermined limit, whereby the locking device can prevent relative displacement of the two coupling elements relative to each other along the first axis in at least the first direction. The locking device has a locking element that is circumferentially rotatable around the first axis at least within a defined range, and when the locking element is in a blocking position, relative displacement of the two coupling elements along the first axis is blocked in at least the first direction. [Prior art documents] [Patent documents]

[0015] [Patent Document 1] US Patent Application Publication No. 2014 / 0326212 [Patent Document 2] International Publication No. 2015 / 022071 [Patent Document 3] International Publication No. 2019 / 025511 Summary of the Invention [Problem to be solved by the invention]

[0016] It is an object of the present invention to provide an improved valve actuation system for variable valve timing. A particular object of the present invention is to provide a valve actuation system with a switching device that allows precise switching between different types of valve timing. [Means for solving the problem]

[0017] This problem is solved by a valve actuation device and a combustion engine according to the independent claims. Advantageous developments are claimed in the dependent claims.

[0018] A first aspect of the present invention provides a variable valve actuation device for actuating at least one valve of a reciprocating piston engine, in particular an internal combustion engine, comprising: the valve actuation device comprises a mechanical coupling having a locking element that can be placed into at least first and second positions by a switching device for actuating the coupling; the valve actuator transmitting actuation motion of the at least one valve to the locking element at least in the first position; The switching device is - a guide rod fixedly mounted in the housing, an actuation rod extending generally parallel to the guide rod and axially movable relative to the guide rod; a slotted guide element movably mounted on said guide rod and designed to move said locking element from at least said first position to said second position and vice versa; - a trigger element connected to the slotted guide element in the axial direction of the actuation rod; It is equipped with the slotted guide element and the trigger element are clamped by two spring elements between two stops arranged on the actuation rod, each stop being assigned a respective spring element; the actuation rod is configured to displace at least the slotted guide element and the trigger element in a direction along and / or parallel to the guide rod; The blocking element is configured to interact with the trigger element such that, in a first state, when the actuating rod is axially displaced such that a preload is applied to at least one of the spring elements, the blocking element blocks displacement of the trigger element and the slotted guide element, and in a second state, allows displacement of the trigger element and the slotted guide element to effect actuation of the coupling device.

[0019] The locking element is moved from the first position to the second position or vice versa, in particular by rotation.

[0020] A second aspect of the present invention relates to an internal combustion engine having such a valve actuation device.

[0021] A slotted guide element in the sense of the present invention is preferably a mechanical element capable of transmitting a force and / or a movement to another mechanical element, the design of the slotted guide element allowing the other mechanical element to move independently in a direction different from the direction of the transmitted force or movement.

[0022] Fixed mounting to the housing in the sense of the present invention means fixed relative to a reference frame, in particular relative to the valve actuation device and / or the reciprocating piston engine.

[0023] The invention is based on the realization that the control of the variation of the valve lift curve or valve timing in a combustion engine, especially if it is time-dependent or crankshaft angle-dependent, should be as precise as possible in order for the combustion engine to be operated with optimized consumption and / or emissions and / or at the same time low wear.

[0024] The present invention achieves this by, on the one hand, using a slotted guide element that activates a coupling device to switch between at least two different valve lift curves, with the trigger element being clamped between two stops located on the actuating rod by two spring elements. As a result, the movement induced by the actuating rod does not have to be immediately carried out by the slotted guide element, but can instead be stored as potential energy in the spring elements. Therefore, the exact moment of switching can be independent of the moment of actuation.

[0025] In the first state, the blocking element blocks the displacement of the trigger element and the slotted guide element, so that at least one of the spring elements is preloaded by the movement of the actuating rod, and in the second state, the blocking element allows the displacement of the trigger element and the slotted guide element. By utilizing the blocking element, it is possible to accurately indicate the time when the coupling device is activated, and therefore the switching point. It is only necessary to release the blocking element. Furthermore, the actuating rod only needs to move in one direction along its longitudinal axis or substantially parallel to the respective guide rod.

[0026] Furthermore, switching of multiple valve actuators can be initiated with a single actuating rod, and thus a single actuator, whereby the individual switching events of the valve actuators are offset in terms of timing or crankshaft angle. This is particularly advantageous when different valve actuators are part of different cylinders that are actuated at different times. Thus, actuation of the actuating rod can initiate switching for all cylinders, but switching is triggered in each case only by the blocking element unblocking the trigger element. Switching of individual cylinders in the low load range has proven particularly advantageous.

[0027] In one advantageous embodiment of the valve actuation device, the trigger element and / or the slotted guide element are movably mounted on the actuation rod, which allows the slotted guide element and / or the trigger element to be mounted without the need for additional mounting means, which also allows for improved force transmission from the actuation rod to the trigger element and the slotted guide element.

[0028] In a further advantageous embodiment of the valve actuation device, the actuation rod passes through the spring element, which allows the spring element to be attached without any other means, in other words, the spring element is attached to the actuation rod in one advantageous embodiment, whereby the spring element is advantageously designed as a spiral spring element or an element respectively running around the actuation rod.

[0029] In a further advantageous embodiment of the valve actuation device, the coupling device further comprises a tappet, which is fixed to the locking element and interacts with a link of the slotted guide element for displacing, in particular rotating, the locking element. The provision of the tappet makes it particularly easy for the slotted guide element to actuate the coupling device.

[0030] In a further advantageous embodiment of the valve actuation device, the link movably guides the tappet in the direction of actuation movement, whereby the link is preferably of U-profile design, which is particularly suitable for selectively fixing the element in one direction.

[0031] In a further advantageous embodiment of the valve actuation device, the coupling device further comprises a first coupling element interacting with the locking element, wherein the first coupling element and the locking element are blocked relative to one another in a first position of the locking element so that the coupling device remains substantially within its defined axial length, and in a second position of the locking element, the first coupling element and the locking element are displaceable relative to one another, in particular relative to one another, so that the coupling device is axially shortened compared to its defined length. By providing the locking element, particularly simple switching of the coupling device can be achieved. Preferably, the locking element is pivotable about the longitudinal axis of the coupling device and / or the first coupling element from the first position to the second position. Preferably, the tappet fixed to the locking element extends approximately perpendicular to the longitudinal axis of the coupling device.

[0032] In a further advantageous embodiment of the valve actuation device, the coupling device further comprises a second coupling element that is movable in the axial direction of the coupling device relative to the first coupling element or the locking element and that abuts against the first coupling element or the locking element at least when an actuating movement is transmitted. Since the force transmission connection is realized only by the stop, the second coupling element can lift off from the first coupling element and / or the locking element. Therefore, the coupling device does not have a limiting effect on externally induced movement.

[0033] In another advantageous embodiment of the valve actuation device, the blocking element is designed as a locking disk connected in a rotationally fixed manner to a shaft, in particular a camshaft, with a switching window whose radius decreases over a predetermined angular sector of the locking disk, and the trigger element, in particular the release pin of the trigger element, abuts against a side of the locking disk in a first state, and the switching window is located in the area of ​​the trigger element in a second state. The locking disk has proven to be a particularly simple and fault-resistant mechanical solution for a blocking element that can also be directly controlled via the camshaft. In particular, electronic controls and electrical signals for actuating the blocking element are not required in this case.

[0034] In a further advantageous embodiment of the valve actuation device, the trigger element is rotatable about an axis of rotation that runs parallel to the guide rod or about the guide rod, in particular about an axis of rotation at least in the direction of rotation of the locking disc, which prevents the blocking element from damaging the trigger element.

[0035] The features and advantages discussed above in relation to the first aspect of the invention equally apply to the second aspect of the invention, and vice versa.

[0036] In one advantageous embodiment, the internal combustion engine has at least two cylinders, each with one valve actuator per cylinder, whereby an actuating rod extends from cylinder to cylinder and is configured to displace in each case at least the slotted guide element and the trigger element towards the guide rod, in other words, the actuating rod extends along all cylinders, preferably approximately parallel to the longitudinal plane of the internal combustion engine formed by the longitudinal axes of the cylinders. [Brief explanation of the drawings]

[0037] [Figure 1]FIG. 1 is a perspective view of an exemplary embodiment of a valve actuation device. [Figure 2] FIG. 2 is a plan view of an exemplary embodiment of the valve actuation device according to FIG. 1. [Figure 3] 1 and 2 in a cross-sectional view along line II of FIG. 2; FIG. [Figure 4] 1 and 2 in a cross-sectional view along line II-II of FIG. 3; FIG. [Figure 5] 2 is a detailed view of the enlarged perspective view according to FIG. 1 of an exemplary embodiment of a valve actuation device. [Figure 6] FIG. 10 is a perspective detail view of a slotted guide element. [Figure 7] FIG. 7 is a plan view of the slotted guide element according to FIG. 6; [Figure 8] 3 is a further plan view of the exemplary embodiment of the valve actuation device according to FIGS. 1 and 2 in a first state; FIG. [Figure 9] 8 is a plan view of the exemplary embodiment of the valve actuation device according to FIGS. 1 and 2 at the start of the switching window in a second state. [Figure 10] 8 and 9 are plan views of the exemplary embodiment of the valve actuation device according to FIGS. 1 and 2 at the end of the switching window in a second state. [Figure 11] 3 is an enlarged plan view of an exemplary embodiment of the valve actuation device according to FIGS. 1 and 2 at the end of the switching window in a second state. [Figure 12] 3 is an enlarged plan view of an exemplary embodiment of the valve actuation device according to FIGS. 1 and 2 after the switching window. FIG. [Figure 13] 3 is an exemplary embodiment of two different valve lift curves that can be realized with the valve actuation device according to FIGS. 1 and 2; DETAILED DESCRIPTION OF THE INVENTION

[0038] Further advantages and features of the present invention will become apparent from the following description and drawings, which are at least partly schematic.

[0039] FIG. 1 illustrates in perspective view an exemplary embodiment of a valve actuation system 100 designed to actuate a combustion engine valve (not shown here).

[0040] In the illustrated exemplary embodiment, the valve actuation device 100 comprises a first rocker arm 210 and a second rocker arm 211, whereby the two rocker arms 210, 211 are preferably rotatably mounted about a common axis of rotation 213. A push rod 220 is connected, in particular operatively connected, to the first rocker arm 210 in order to transmit an actuation movement from the first rocker arm 210 and / or the second rocker arm 211 to the valve. Instead of rocker arms, the invention can also be implemented using other transmission elements, for example rocker beams.

[0041] The first rocker arm 210 is designed to mark the contour of the first cam 214, and the second rocker arm 211 is designed to mark the contour of the second cam 215. The two cams 214, 215 are in particular rotatably mounted on a common shaft 216. Preferably, the first cam 214 has a different contour than the second cam 215 in the circumferential direction of the shaft 216 and / or the cam lobes are circumferentially offset from each other.

[0042] The first rocker arm 210 and the second rocker arm 211 are connected via a connecting device 10. The connecting device 10 is configured in particular to transmit an actuation movement from the second rocker arm 211 to the first rocker arm 210 when the connecting device 10 is in a blocked state, or to convert a movement of the second rocker arm 211 into a so-called lost motion movement when the connecting device 10 is in an unblocked state.

[0043] In the exemplary embodiment as shown, the coupling device 10 is arranged on the second rocker arm 211 or on a component of the second rocker arm 211, respectively. Preferably, the longitudinal axis A (see FIG. 3) of the coupling device 10, along which the length of the coupling device 10 is adjustable, lies tangential to the orbit of the second rocker arm 211 about the axis of rotation 213. The longitudinal axis A extends substantially radially along or, respectively, parallel to the shaft 216.

[0044] In particular, the first rocker arm 210 preferably extends within the track of the second rocker arm 211 and has a connecting portion 217 that is operatively connected to the second rocker arm 211 or the connecting device 10, respectively, via an adjustable second connecting element 12 (see FIG. 3) that can be mounted in the connecting portion 217 via, for example, a lock nut 221, for transmitting the actuating movement.

[0045] For longitudinal adjustment, the coupling device 10 preferably comprises a first coupling element 11 (not shown in FIG. 1 - see e.g. FIG. 3) and a preferably sleeve-like locking element 13B. In a first position, which corresponds to the above-mentioned unblocked state of the coupling device 10, the coupling element 11 and the locking element 13B are axially, preferably telescopically, displaceable relative to one another along the longitudinal axis A of the coupling device 10.

[0046] To switch the coupling device 10 between the unblocked and blocked states, the locking element 13B is preferably rotatable circumferentially about the longitudinal axis A of the coupling device 10, and thus between at least a first position corresponding to the unblocked state of the coupling device 10 and a second position corresponding to the blocked state of the coupling device 10. Relative displacement between the first coupling element 11 (FIG. 3) and the locking element 13B is blocked along the longitudinal axis A, and thus the coupling device 10 is in the blocked state when the locking element 13B is in the first position (hereinafter referred to as the blocked position). Thus, when the locking element 13B is in the second position (hereinafter referred to as the non-blocking position), relative displacement between the first coupling element 11 and the locking element 13B along the longitudinal axis A is permitted, and the coupling device 10 is in the unblocked state.

[0047] The locking element 13B preferably has a radially outwardly extending tappet 13A which serves to activate the locking element 13B by means of the switching device 110. In particular, the tappet 13A extends radially relative to the longitudinal axis A of the coupling device 10 or extends substantially perpendicularly to the longitudinal axis A. Preferably, the locking element 13B forms a locking device together with the tappet 13A. The tappet 13A is preferably arranged to interact with a link 85 of a slotted guide element 84 of the switching device 110 which is preferably designed to correspond to the tappet 13A.

[0048] Thereby, the switching device 110 is fixedly mounted to the combustion engine housing, preferably together with a control valve (neither shown), independent of the rocker arms 210, 211. The switching device 110 is preferably hydraulically or electromechanically actuated by an actuator (not shown) and more preferably controlled by a controller (ECU) of the combustion engine.

[0049] The locking disc 112 is non-rotatably connected to the shaft 216. As will be explained below, this serves to prevent or allow actuation of the coupling device 10 by the switching device 110.

[0050] FIG. 2 shows a plan view of the side opposite the axis of rotation 213 of the valve actuation device 100 of the exemplary embodiment according to FIG.

[0051] The first rocker arm 210 is shown on the left side of Figure 2. A first path F1 of force transmission, shown as a solid arrow, from the first cam 214 to the first rocker arm 210, through the first pickup 218 to the push rod 220 preferably extends substantially parallel to the direction of movement of the first rocker arm 210.

[0052] The second rocker arm 211 is shown on the right side of Fig. 2. Force transmission from the second rocker arm 211 to the first rocker arm 210 occurs only when the coupling device 10 is in a blocked state. When the coupling device 10 is in a blocked state, a second path F2 of force transmitted from the second cam 215 and the second rocker arm 210 to the coupling device 10 via the second pickup 219 extends approximately parallel to the direction of movement of the second rocker arm 211. The second path F2 of force transmission from the coupling device 10 preferably extends to the first rocker arm 210 and the push rod 220 via the coupling part 217, in particular approximately perpendicular to the axis of movement of the second rocker arm 211.

[0053] Therefore, in the illustrated embodiment, path F1 is always enabled, while path F2 is selectively activated depending on the state of the coupling device 10.

[0054] Figure 3 shows a cross-sectional view of an embodiment of the second rocker arm 211 of the valve actuation device 100 in plane II from Figure 2, in which lies the central axis A of the coupling device 10. As already explained to some extent with reference to Figure 1 and as is fully clear from Figure 3, the coupling device 10 comprises a first coupling element 11, a locking element 13B with a tappet 13A, and further a second coupling element 12.

[0055] The first connecting element 11 is fixed to transmit forces to the second rocker arm 211, and the second connecting element 12 is fixed to transmit forces to the first rocker arm 210, preferably to its connecting portion 217, and more preferably is screwed in and / or is fixed or adjustable in terms of its position relative to the first connecting element 11 or locking element 13B, respectively, by a lock nut 221.

[0056] In this exemplary embodiment, the locking element 13B is fully engaged around the periphery of the first connecting element 11. That is, in this exemplary embodiment of the connecting device 10 according to the present invention, the locking element 13B is in a circumferentially closed configuration.

[0057] 4 shows a detail of the cross section of the actuating device 100 in the II-II plane of FIG. 3 in the region of the coupling device 10. To enable blocking and then unblocking again, the first coupling element 11 of the coupling device 10 has a first portion 16 with outer longitudinal toothing extending in the longitudinal direction of the first coupling element 11, and a second portion 18 also extending in the longitudinal direction of the first coupling element 11 and not having any toothing directly adjacent to the first portion 16. Furthermore, a third portion 19 is provided adjacent to the second portion 18, which also extends in the longitudinal direction of the first coupling element 11 and also has outer longitudinal toothing. By longitudinal toothing, we mean structures, such as grooves, prismatic projections, etc., extending substantially parallel to the longitudinal direction A of the coupling device 10.

[0058] The sleeve-shaped locking element 13B has, over part of its axial length (in particular parallel to the longitudinal axis A of the coupling device 10), inner longitudinal toothing 17 whose design corresponds to the shape of the toothing of the first and third parts 16, 19. The inner longitudinal toothing 17 only extends axially over a region whose length corresponds at most to the width of the toothless second part 18, and the locking element 13B is rotatable about a first axis (which substantially corresponds to the longitudinal axis A of the coupling device 10) when the first coupling element 11 with its outer longitudinal toothing is axially displaced relative to the locking element 13B, so that the inner longitudinal toothing 17 of the locking element 13B does not engage with the outer longitudinal toothing of the first coupling element 11, but rather is at the height of the toothless second part 18, i.e., between parts 16 and 19.

[0059] Thus, in this connecting device 10, the outer diameter of the toothless second part 18 of the first connecting element 11 is smaller than the tip diameter of the outer longitudinal toothing of the first part 16 of the first connecting element 11, whereby, in particular, the outer diameter of the second part 18 is smaller than or equal to the root diameter of the outer longitudinal toothing of the first part 16.

[0060] The outer longitudinal toothing of the third part 19 serves to improve the guiding of the first connecting element 11 in the locking element 13B, and the tooth shape of the outer longitudinal toothing of the third part 19 is preferably of the same design as the tooth shape of the outer longitudinal toothing of the first part 16.

[0061] Thus, in this exemplary embodiment, the third portion 19 is located at the free end of the first connecting element 11, directly adjacent to the toothless second portion, and the individual teeth of the third portion 19 are aligned with the outer longitudinal teeth of the first portion 16.

[0062] Thereby, the locking element 13B is in a blocking position when the connecting element 11 with its outer longitudinal toothing is displaced axially relative to the locking element 13B such that its inner longitudinal toothing 17 is not engaged with the outer longitudinal toothing of the first part 16 of the first connecting element 11 and the inner longitudinal toothing 17 of the locking element 13B is instead axially at the level of the toothless second part 18, and when the locking element 13B is rotated circumferentially, i.e. around the first axis (corresponding to the longitudinal axis A), at least one tooth, in particular all teeth, of the outer longitudinal toothing of the first part 16 of the first connecting element 11 is at least partially axially aligned with at least one tooth, in particular all teeth, of the inner longitudinal toothing 17 of the locking element 13B, in particular so that their end faces abut each other.

[0063] The transmission of the actuation movement of the second rocker arm 211 to the first rocker arm 210 occurs when the locking element 13B is in the blocking position and the relative axial displacement of the connecting element 11 and the locking element 13B with respect to each other is blocked. In this blocking position, the locking element 13B follows the movement of the first connecting element 11, which is fixedly connected to the second rocker arm, and transmits the actuation movement of the second rocker arm 211 to the second connecting element 12.

[0064] Thus, when the locking element 13B is rotated circumferentially, the locking element 13B is in the non-blocking position such that all teeth of the outer longitudinal toothing of the first portion 16 of the first connecting element 11 are arranged offset with respect to all teeth of the inner longitudinal toothing 17 of the locking element 13B and the teeth of the outer longitudinal toothing of the first connecting element 11 engage with the teeth of the inner longitudinal toothing 17 over at least a portion of their axial length. When the locking element 13B is in the non-blocking position, the movement of the second rocker arm 211 is, conversely, dissipated or, respectively, nullified, so that the first connecting element 11 can dip unhindered into the cylindrical portion of the locking element 13B without any movement of the first connecting element 11 being transmitted to the second connecting element 12.

[0065] The locking element 13B is preferably axially supported against the second connecting element 12 by a spring element 49 when the locking element 13B is in the non-blocking position. To improve guiding of the second connecting element 12, the cylinder base of the locking element 13B is preferably inwardly curved and the free end of the second connecting element 12 is correspondingly convexly curved.

[0066] In this manner, predetermined valve lifts can be selectively enabled or disabled by a mechanical switching device.

[0067] FIG. 5 shows an enlarged perspective view of FIG. 1, particularly illustrating an embodiment of the switching device 110 of the valve actuation device 100.

[0068] The switching device 110 comprises a slotted guide element 84 and a trigger element 111, the slotted guide element 84 being configured to actuate the coupling device 10. The slotted guide element 84 allows the tappet 13A to be displaced in order to rotate the locking element 13B to its end about the longitudinal axis A of the coupling device 10. This allows the slotted guide element 84 to be displaced substantially parallel to the shaft 216 (not shown in FIG. 5 ) and / or the axis of rotation 213. To improve the interaction between the slotted guide element 84 and the locking element 13B, the slotted guide element 84 preferably has, at its end facing the tappet 13A, a jaw 85 designed to interact with the tappet 13A of the locking element 13B and preferably designed with a U-shaped profile. The slotted guide element 84 is preferably movably mounted on the guide rod 83 and the actuating rod 81, and the trigger element 111 is mounted on at least the actuating rod 81. The longitudinal axes of the guide rod 83 and the actuation rod 81 extend parallel to each other and preferably also parallel to the axis of rotation 213 and the shaft 216, but perpendicular to the longitudinal axis A of the actuation movement and coupling device 10. The actuation rod 81 is configured to move the slotted guide element 84 on the guide rod 83.

[0069] To that end, the slotted guide element 84 and the trigger element 111 are clamped by two spring elements 93, 94 between two stops 89, 89' arranged on the actuating rod 81 (the stops 89' are hidden in FIG. 5 ). The stops 89, 89' are thereby preferably designed as annular discs fixed to the actuating rod 81 in order to prevent axial displacement of the spring elements 93, 94 along the longitudinal axis of the actuating rod 81 and to allow preloading of the spring elements 93, 94 against the slotted guide element 84.

[0070] 6 and 7 show detailed views of the slotted guide element 84. What can be particularly seen therefrom is that the U-shaped profile of the jaw 85 is formed substantially in a plane oriented perpendicular to the longitudinal axis A of the coupling device 10. This ensures the best possible encirclement of the tappet 13A by the jaw 85. As used herein, U-shaped profile refers to the provision of a first jaw arm 85a and a second jaw arm 85b, which extend from the base and interact with the tappet 13A depending on the direction of movement of the slotted guide element 84 along the guide rod 83.

[0071] 6 and 7, the portion of the slotted guide element 84 that interacts with the actuating rod 81 and the guide rod 83 is also substantially U-shaped. A first actuating arm 95a and a second actuating arm 95b extend from a guide part 95 that surrounds the guide rod 83 and is movable along the guide rod 83, and their distal ends from the guide rod 83 loosely surround the actuating rod 81, so that the actuating rod 81 is movable relative to the actuating arms 95a, 95b or the slotted guide element 84, respectively. The actuating arms 95a, 95b thereby act, on the one hand, as stops for the spring elements 93, 94, respectively, allowing a preload relative to the stops 89, 89′. On the other hand, a trigger element 111, also movable along the actuating rod 81, is arranged with an associated return spring 114 between the actuating arms 95a, 95b, so that the trigger element 111 also moves when the slotted guide element 84 moves.

[0072] The guide portion 95, together with the actuating arms 95a, 95b, are connected to the jaw portion 85 via a connection portion 96, and preferably the guide portion 95, the actuating arms 95a, 95b, the jaw portion 85, and the connection portion 96 are of one unitary construction. In the exemplary embodiment shown, the connection portion 96 originates from the second actuating arm 95b, although other embodiments are possible.

[0073] The switching device 110 comprises a blocking element 112 designed to interact with the trigger element 111 to prevent or allow axial displacement of the slotted guide element 84. The blocking element 112 in the illustrated embodiment is configured in the form of a locking disk, as already mentioned above. Therefore, in the following, the reference number 112 is used generally for the locking element and the locking disk, respectively. The locking disk 112 is mounted on a shaft 216 that is axially offset with respect to the first and second cams 214, 215 and can therefore rotate synchronously with the two cams 214, 215.

[0074] The trigger element 111 in the illustrated embodiment has a release pin 115 which is arranged projecting radially from the actuation rod 81 and which can interact with the locking disc 112. The release pin 115, or the entire trigger element, is preferably pivotally mounted around the actuation rod 81 and is further preferably held in a predetermined arrangement relative to the slotted guide element 84 by a return spring 114. Here, the defined configuration is to be understood in particular as the direction in which the release pin 115 projects radially from the actuation rod 81.

[0075] In the first position, the release pin 115 is located on a first side of the locking disc 112 opposite the coupling device 10. Preferably, the release pin 115 is configured so that it can roll along the locking disc 112, which rotates with the shaft 216, when required.

[0076] When the actuating rod 81 is displaced axially towards the coupling element 10 to switch the switching device 10, the release pin 115 is locked on the locking disc 112. This therefore also prevents displacement of the trigger element 111 and the slotted guide element 84 along the actuating rod 81 or the guide rod 83, respectively. This preloads the first spring element 93, which is arranged on the side of the slotted guide element 84 opposite the coupling element 10.

[0077] The locking disc 112 has a switching window 113 in the form of a void on its outer periphery, which is designed so that the trigger element 111, in particular the release pin 115, can pass through the switching window 113 when the switching window 113 is located in the area of ​​the release pin 115 on the locking disc 112 rotating about the axis 216. The longitudinal extension of the switching window 113 along the circumference of the locking disc 112 defines a window of time during which actuation of the coupling device 10 by the switching device 110 is possible.

[0078] The trigger element 111, and in particular the release pin 115, passing through the switching window 113 as a result of the preload of the spring element 93, allows a displacement of the trigger element 111 and the slotted guide element 84. The trigger element 111 and the slotted guide element 84 are then displaced axially along the operating rod 83, here in the direction of the coupling device 10. The axial displacement of the slotted guide element 84 causes a rotational movement of the locking element 13B, in particular via the tappet 13A, which moves the locking element 13B from a blocking position to a non-blocking position or vice versa.

[0079] In the second position, the release pin 115 is arranged on a second side of the locking disc 112 facing the coupling device 10. When the actuating rod 81 is displaced axially away from the coupling element 10, the release pin 115 contacts the locking disc 112 outside the switching window 113 and is thus locked on the locking disc 112. Axial displacement of the trigger element 111 and the slotted guide element 84 along the actuating rod 81 or guide rod 83, respectively, is therefore prevented. This preloads the second spring element 94, which is arranged on the side of the slotted guide element 84 facing the coupling element 84.

[0080] The trigger element 111, particularly the release pin 115, passing through the switching window 113 as a result of the preload of the spring element 93 allows displacement of the trigger element 111 and the slotted guide element 84. The trigger element 111 and the slotted guide element 84 are then displaced axially on the actuating rod 83, here away from the coupling device 10. The axial displacement of the slotted guide element 84 causes a rotational movement of the locking element 13B, particularly via the tappet 13A, switching the locking element 13B from the blocking position to the non-blocking position or vice versa. FIGS. 8 to 10 show further plan views of the exemplary embodiment of the valve actuation device along the rotation axis 213 or shaft 216, respectively, which in this case extend perpendicular to the plane of the paper, this time from the side opposite the slotted guide element 84. The release pin 115 is thus either in a first position (FIG. 8, hidden by the locking disc 112) or in a second position (FIGS. 9 and 10). These figures will be referenced in explaining the switching process by the switching device 110.

[0081] 8, the release pin 115 is in a first position. As the actuating rod 81 determines the switching of the switching device 110, a force is exerted via a spring element (not shown) on the trigger element 111 and therefore on the release pin 115 to reach the second position. As the locking disc 112 prevents the displacement of the trigger tappet and thus of the release element 111 and the slotted guide element 84, the release pin 115 abuts against the locking disc 112, whereby a roller attached to the release pin 115 rolls along the invisible side of the locking disc 112, which rotates together with the first cam 214.

[0082] When the release pin reaches the void or switching window 113 in the locking disc 112, the release pin 115 passes through the void 113 and reaches the second position. The trigger element 111 and the slotted guide element 84 connected to the trigger element 111 are displaced on the guide rod 83 and the actuation rod 81 by the release pin 115. This state is shown in Figure 9.

[0083] 10, the cam 214 and the locking disc 112 have rotated further so that the release pin reaches the end of the void in the switching window 113. The release pin 115 should now be in the second position and then starts to roll along the visible side of the locking disc 112. The trigger element 111 and the slotted guide element 84 are then blocked and both can be pretensioned again by the actuating rod 81, this time in the opposite direction.

[0084] However, at the end of the void in the switching window 113, when the lock disc 112 is in an intermediate position between the first and second positions, the flanks of the lock disc 112 apply a load to the release pin in the rotational direction of the lock disc, which may result in the lock pin breaking.

[0085] This is prevented by pivotally mounting the release pin 115 or the entire trigger element 111, in particular against the force of the protective spring 114. Preferably, the trigger element 111 is pivotally mounted on the actuation rod 81 up to its end, as shown in the figures. The protective spring 114 always returns the release pin 115 to its original position.

[0086] 11 and 12, the release pin 115 can pivot away if, due to misalignment, it contacts the side of the void or the respective switching window 113. When the trigger element 111 finally reaches the second position, it is again pivoted rearward by the force provided by the return or protection spring 114 (not shown in FIGS. 11 and 12).

[0087] Figure 13 shows exemplary embodiments of two different valve lift curves that can be realized with the valve actuation system 100 according to Figures 1 and 2, thereby providing the valve opening as a function of crankshaft angle.

[0088] The IVC-480 valve lift curve is from a Miller cycle and is generated by the first cam 214, and therefore, in the exemplary embodiment of the valve actuation system 100 shown in the previous figure, a so-called Miller cam.

[0089] The operation of a combustion engine in Miller operation is particularly optimized with regard to consumption, but in Miller operation it is not possible to start because the cylinder fill is too low.

[0090] The IVC-580 valve lift curve belongs to a different combustion cycle, in which the valves have a larger valve lift (8.7 mm greater) and are open longer than in the illustrated Miller cycle. This IVC-580 valve lift curve is generated by the second cam 215. Therefore, the IVC-580 valve lift curve overlaps with the IVC-480 valve lift curve.

[0091] As shown in Figure 13, the rise in the IVC-580 valve lift curve follows the rise in the IVC-480 valve lift curve over time. This ensures that the majority of the forces generated within the valve actuation device 100 when the valve opens are transmitted through the more stable and stiff first rocker arm 210 (force flow F1). In that case, only about one-third of the force is acting on the variable or adjustable rocker arm 211. This allows for a less rigid design and allows for smaller dimensions, particularly narrower dimensions.

[0092] Therefore, the flank of the second cam 215 rises later than the flank of the first cam 214 relative to the direction of rotational movement of the shaft 216. As a result, the actuation movement of the first rocker arm 210 occurs at a different, preferably earlier, point in time than the actuation movement of the second rocker arm 211. Combustion engines, especially so-called large engines, are preferably operated in the Miller cycle for more than 90% of their operating time. The IVC-580 valve lift curve is preferably used only during start-up and transient sailing modes (also called coasting modes).

[0093] It should be noted that the exemplary embodiments described above are merely examples that are not intended to limit the scope of protection, applications, and configurations in any way. Rather, the foregoing description provides a guideline for those skilled in the art for implementing at least one exemplary embodiment, whereby various modifications can be made, particularly with regard to the function and arrangement of the described components, without departing from the scope of protection arising from the claims and equivalent combinations of features. In particular, the valve actuation device may be a cam follower or rocker or similar device. Furthermore, the switching device may be of different configurations, particularly according to the variants shown in Patent Document 3. [Explanation of symbols]

[0094] 10 Coupling device 11 First connecting element 12 Second connecting element 13A tappet 13B Locking Elements 16 First portion of first connecting element 11 17 inner longitudinal tooth of sleeve-like locking element 13B 18 second part of first connecting element 11 19 third portion of first connecting element 11 81 Actuating rod 83 Guide rod 84 Slotted Guide Element 85 Link, jaw, U-profile 85a First Jaw Arm 85b Second Jaw Arm 89 Stopper 93,94 Spring elements 95 Guide part 95a first actuation arm 95b second actuation arm 100 Valve Actuator 110 Switching Device 111 Trigger Elements 112 Blocking Elements 113 Switching Window 114 Protection spring 115 Release pin 210 First rocker arm 211 Second Rocker Arm 213 Rotation axis 214 First Cam 215 Second Cam 216 Shaft 217 Connecting part 218 First Pickup 219 Second Pickup 220 push rod 221 Lock nut A longitudinal axis of the coupling device 10 F1 first power path F2 Second force path

Claims

1. A valve actuation device (100) for actuating at least one valve of a reciprocating piston engine, comprising: The valve actuation device (100) comprises a mechanical coupling (10) having a locking element (13B) that can be brought to at least a first position and a second position by a switching device (110) for actuating the coupling device (10); the valve actuation device (100) transmits actuation movement of the at least one valve to the locking element (13B) at least in the first position; The switching device (110) - guide rod (83), an actuating rod (81) extending substantially parallel to said guide rod (83) and axially movable relative to said guide rod; - slotted guide elements (84, 85) movably mounted on said guide rod (83) and designed to move said locking element (13B) at least from said first position to said second position and vice versa; a trigger element (111) connected to said slotted guide elements (84, 85) in the axial direction of said actuation rod (81); It is equipped with the slotted guide element (84, 85) and the trigger element (111) are clamped by two spring elements (93, 94) between two stops (89, 89') arranged on the actuation rod (81), each stop being assigned a respective spring element (93, 94); the actuation rod (81) is configured to displace at least the slotted guide elements (84, 85) and the trigger element (111) in a direction along and / or parallel to the guide rod (83); a blocking element (112) configured to interact with the trigger element (111) such that, in a first state, the blocking element (112) blocks displacement of the trigger element (111) and the slotted guide elements (84, 85) when the actuating rod (81) is axially displaced such that a preload is applied to at least one of the spring elements (93, 94), and, in a second state, the blocking element (112) allows displacement of the trigger element (111) and the slotted guide elements (84, 85) to effect actuation of the coupling device (10).

2. 2. The valve actuation device of claim 1, wherein the trigger element (111) and / or the slotted guide element (84, 85) are movably mounted on the actuation rod (81).

3. 3. The valve actuation device of claim 2, wherein the actuation rod (81) passes through the spring elements (93, 94).

4. 4. The valve actuation device according to claim 1, wherein the coupling device (10) further comprises a tappet (13A) fixed to the locking element (13B) for interacting with a link (85) of the slotted guide element (84) to displace the locking element (13B).

5. 5. A valve actuation device according to claim 4, wherein the link (85) movably guides the tappet (13A) in the direction of actuation movement.

6. 6. The valve actuation device according to claim 1, wherein the coupling device further comprises a first coupling element interacting with the locking element, the first coupling element and the locking element being blocked relative to one another in the first position of the locking element such that the coupling device remains sufficiently within its defined axial length, and in the second position of the locking element the first coupling element and the locking element are displaceable relative to one another such that the coupling device is axially shortened compared to its defined length.

7. 7. The valve actuation device according to claim 6, wherein the coupling device (10) further comprises a second coupling element (12) that is movable in the axial direction of the coupling device (10) relative to the first coupling element (11) or the locking element (13B) and that abuts against the first coupling element (11) or the locking element (13B) at least when the actuating motion is transmitted.

8. 8. The valve actuation device according to claim 1, wherein the blocking element (112) is designed as a locking disc (112) connected in a rotationally fixed manner to the shaft (216) and has a switching window (113) whose radius decreases over an angular sector of the locking disc (112), and wherein the trigger element (111) abuts a lateral surface of the locking disc (112) in the first state and the switching window (113) is arranged in the area of ​​the trigger element (111) in the second state.

9. 2. The valve actuation device of claim 1, wherein the trigger element (111) is rotatable about an axis of rotation extending parallel to the guide rod (83) or directly about the guide rod (83).

10. A valve actuation device as described in Claim 9, wherein the blocking element (112) is designed as a locking disk connected to the shaft (216) in a rotationally fixed manner, and the trigger element (111) is rotatable around the rotation axis at least in the rotational direction of the locking disk (112).

11. An internal combustion engine equipped with the valve actuation device according to any one of claims 1 to 10.

12. 11. An internal combustion engine having at least two cylinders, each cylinder being provided with one valve actuation device according to any one of claims 1 to 10, wherein the actuation rod (81) extends from cylinder to cylinder and is configured in each case to displace at least the slotted guide elements (84, 85) and the trigger element (111) towards the guide rod (83).

Images