Valve Actuator

Abstract

The present invention relates to a valve actuation device (100) for actuating at least one valve of a reciprocating engine, the valve actuation device comprising: a first actuation lever (210) and a second actuation lever (211) mounted for rotation about a common axis of rotation (213), the first actuation lever (210) being connectable to at least one valve so as to transmit an actuation motion to the valve; two cams (214, 215) arranged on a shaft (216), the actuation levers (210, 211) gripping the contours of the cams (214, 215); The invention further relates to an internal combustion engine (101) comprising a valve actuation device (100) comprising: a cam (214, 215); a mechanical coupling (10) for connecting actuating levers (210, 211), the mechanical coupling (10) comprising a shutoff element (13B) movable in two positions and configured to transmit an actuating movement of the second actuating lever (211) to the first actuating lever (210) at least in a first position of the shutoff element (13B); and a switching device (110) for switching the shutoff element (13B) of the coupling device (10) between positions, the switching device (110 being configured such that a movement of the second actuating lever (211) mechanically causes a change in the position of the shutoff element (13B).

Description

[Technical field]

[0001] The present invention relates to a valve actuation device for actuating at least one valve of a reciprocating engine, in particular an internal combustion engine, the valve actuation device having a first actuating lever and a second actuating lever, the two actuating levers being mounted so as to be rotatable about a common axis of rotation, the first actuating lever being connectable to at least one valve so as to transmit an actuating motion to the at least one valve, the valve actuation device having a first cam and a second cam, the two cams being arranged on a shaft, the first actuating lever gripping the contour of the first cam and the second actuating lever gripping the contour of the second cam. [Background technology]

[0002] Valve actuation devices of this kind and internal combustion engines equipped with such valve actuation devices are basically known from the prior art.

[0003] 2. Description of the Related Art Variable valve trains, i.e., valve trains with variable valve lift, are becoming increasingly important in reciprocating internal combustion engines, particularly four-stroke and six-stroke reciprocating internal combustion engines, due to ever increasing demands regarding performance, efficiency and emissions.

[0004] A variable valve mechanism can be used to meet the needs of engine designers and thermodynamic requirements to selectively deliver different valve lift curves to one or more valves depending on the operating conditions of the engine, and can adjust both valve lift and opening and closing times.

[0005] This is generally achieved by switching the transmission path of the valve train. Stroke switching and stroke deactivation systems with switchable cam followers, such as bucket tappets, roller tappets or rocker levers, are mass-produced for various applications. It is important here that for a further alternative valve lift, a corresponding cam must also be present as lift element, unless the alternative lift is zero lift.

[0006] There are many different applications for the use of valve trains with unsteady or variable valve lift. Some examples are given below:

[0007] Stroke switching: Stroke switching allows at least two different valve lifts to be used depending on the operating point. A smaller valve lift is used, which is specifically adapted to the part load range, improving the torque curve and reducing consumption and emissions. A larger valve lift can be optimized for a further increase in power. A smaller valve lift with a smaller maximum lift and a shorter event length can reduce the gas exchange work (Miller cycle) by a significantly earlier end of intake and the elimination of the throttling in the intake stroke. Similar results are obtained with the Atkinson cycle, i.e. with an extremely late end of intake. An optimal filling of the combustion chamber still results in an increase in torque in the part load range.

[0008] Cylinder deactivation: Cylinder deactivation is mainly used in large-capacity 4-cylinder engines (e.g. 4-, 8-, 10- or 12-cylinder engines). Selected engine cylinders are deactivated by stroke deactivation of the intake and exhaust valves, resulting in a complete decoupling from the cam lift. Due to the equidistant firing order, typical V8 and V12 drives can then be transformed into A4 or R6 engines. The aim of engine cylinder deactivation is to minimize gas exchange losses and to effect a shift of the operating point towards higher mean effective pressures and higher thermodynamic efficiency, thereby achieving significant fuel savings.

[0009] Engine braking operation: Engine braking systems that allow engine braking operation are becoming increasingly important in internal combustion engines of vehicles, especially in commercial vehicles, because they are cost-effective, space-saving auxiliary braking systems that can relieve the load on the wheel brakes, especially when driving relatively long on steep gradients. Furthermore, the increase in the specific power of modern commercial vehicle engines also requires an increase in the available brake power.

[0010] In order to obtain an engine braking effect, it is known to provide the engine cylinders of an internal combustion engine with additional macro valves, by means of which a so-called decompression brake is performed, in particular at the end of the compression stroke of a four-stroke or six-stroke engine, by decompressing the cylinder via the additional engine valve. This causes the work done by the compressed gases to leak out through the exhaust system of the internal combustion engine. Moreover, the internal combustion engine has to do work again to refill the cylinders with gas. It is known, in particular, to generate an engine braking effect by a variable valve mechanism of the actual exhaust valves.

[0011] Various systems and concepts for varying the valve lift are known, in particular the provision of a mechanical or hydraulic coupling between one or more valve actuation elements of a valve actuation device that transmits cam lift, which coupling can be used to realize a change in the transmission path of the valve train.

[0012] For example, US Pat. No. 5,399,633 shows a system for variable valve control, in particular for producing engine braking action, which includes a "lost motion" device with a hydraulically actuable blocking element for selectively blocking or disengaging the valve actuation mechanism so that valve actuation motion is selectively transmitted or not transmitted to one or more valves, varying the valve lift and thereby producing, in particular, engine braking action.

[0013] Patent document 2 discloses a valve actuation device for actuating at least one first valve of a reciprocating engine, in particular an internal combustion engine, which can be used in particular for engine braking, and which has a first rocker lever part, a second rocker lever part and a first switching element for changing the valve lift of the at least one first valve, and the first rocker arm part and the second rocker arm part are pivotally mounted and arranged such that at least one first valve control movement can be transmitted from a first camshaft via the first rocker lever part and the second rocker lever part to the at least one first valve.

[0014] Patent Document 3 relates to a valve actuation device for actuating at least one valve of a reciprocating engine with variable valve lift, in particular a coupling device for a valve actuation device of a reciprocating internal combustion engine, a valve actuation device and a reciprocating engine, the coupling device having a first coupling element, a second coupling element and a blocking device. The first coupling element and the second coupling element are displaceable relative to each other within a boundary determined at least along a first axis, and the blocking device can be used to block the relative displacement of the two coupling elements along the first axis in at least a first direction. The blocking device has a blocking element that is rotatable around the first axis at least within a determined range in the circumferential direction, and when the blocking element is in a blocking position, the relative displacement of the two coupling elements along the first axis in at least a first direction is blocked. The disclosure of Patent Document 3 is incorporated herein by reference.

[0015] The applicant's patent document 4 relates to a valve actuation device for actuating a valve of a reciprocating engine, the valve actuation device having a coupling device with a shutoff element movable to a first position and a second position by a mechanical switching device for actuating a coupling device, the valve actuation device transmitting an actuating motion for the valve in the first position, the switching device having a guide rod, an operating rod movable in parallel and relatively to the guide rod, a link guide element movably attached to the guide rod for moving the shutoff element between each position, a release element connected to the link guide element, the link guide element and the release element being clamped by means of a spring element between two stoppers of the operating rod on which the spring element is disposed, the link guide element and the release element being displaceable together with the operating rod in a direction along and / or parallel to the guide rod, and a blocking element cooperating with the release element such that in a first state the blocking element blocks the displacement of the release element and the link guide element such that a pretension is applied to the spring element when the operating rod is displaced axially, and in a second state the displacement of the release element and the link guide element causes the actuation of the coupling device. The disclosure of US Pat. No. 5,999,633 is also incorporated herein by reference. [Prior art documents] [Patent documents]

[0016] [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 [Patent Document 4] Austrian Patent Invention No. 50710 / 2020 Summary of the Invention [Problem to be solved by the invention]

[0017] It is an object of the present invention to provide an improved valve actuation device for variable valve control, in particular a valve actuation device for variable valve control, which allows particularly accurate synchronization of the valve lift switching. [Means for solving the problem]

[0018] This problem is solved by a valve actuation device and an internal combustion engine according to the independent claims. Advantageous embodiments are defined in the dependent claims.

[0019] A first aspect of the invention relates to a valve actuation device for actuating at least one valve of a reciprocating engine, in particular an internal combustion engine, comprising: a first actuating lever and a second actuating lever, the two actuating levers being mounted so as to be rotatable about a common axis of rotation, the first actuating lever being connectable to at least one valve so as to transmit an actuating motion to the at least one valve; a first cam and a second cam, these two cams being arranged on one, in particular a common, shaft, the first actuating lever gripping the contour of the first cam and the second actuating lever gripping the contour of the second cam; a mechanical coupling device capable of connecting a first actuating lever and a second actuating lever to each other, the coupling device having a blocking element movable to at least a first position and a second position, the coupling device being configured to transmit an actuating movement of the second actuating lever to the first actuating lever, at least in the first position of the blocking element; and a switching device for moving a shut-off element of a coupling device at least from a first position to a second position and vice versa, wherein a movement of a second actuating lever, in particular a movement leading to the closing of at least one valve and / or a movement in the direction of a second cam, is configured to mechanically cause a change in the position of the shut-off element; It has.

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

[0021] The invention is based on the approach of realizing variable valve control by means of two actuating levers, where the first actuating lever generates the valve actuation movement continuously, while the second actuating lever can be actuated on demand by means of a switching device, the valve actuation movement generated by the second actuating lever being superimposed on the valve actuation movement of the first actuating lever. In this case, the valve actuation movement of the second actuating lever is transmitted to the first actuating lever via a coupling device, and only the first actuating lever is always actuated through the valve. In the case of a rocker arm, this is preferably done via a pushrod.

[0022] Preferably, the first force transmission path via the first actuating lever is not affected by the presence of the second actuating lever. The coupling device directs the second force transmission path from the second actuating lever to the first actuating lever, from which the second force transmission path extends to the valve in the same way as the first force transmission path.

[0023] The invention thus combines the advantages of a stiff actuating lever with the advantages of adjustable valve control: on the one hand, large forces for actuating the valve can be transmitted only through the first actuating lever, while on the other hand fine adjustment of the valve and / or auxiliary actuation of the valve can be obtained by adding a second actuating lever.

[0024] Furthermore, the invention makes it possible to obtain the initiation or termination of the actuating movement through the second actuating lever by the movement of the actuating lever itself, which makes it possible to control the optimum switching instants particularly precisely.

[0025] Furthermore, the synchronized switching through the movement of the second actuating lever can provide the maximum time frame available for operation through the first or second actuating lever, respectively, and the mechanical initiation of the switching process also ensures a particularly reliable initiation.

[0026] In an advantageous embodiment of the valve actuator, the valve actuator comprises a release element and the switching device comprises a blocking element configured to cooperate with the release element to block or allow axial displacement of the release element.

[0027] Mechanical release can be achieved by providing a blocking element which cooperates with the release element.

[0028] In a further advantageous embodiment of the valve actuation device, the guide rod is fixed to the housing and is mounted so as to be axially displaceable for actuating the release element.

[0029] In this advantageous embodiment, the guide rod can be directly actuated by the actuator: no further device for actuating the release element is required.

[0030] In a further advantageous embodiment, the release element and the blocking element mechanically cooperate in such a way that a change in position of the blocking element is initiated when the second actuating lever is moved in the direction of the shaft.

[0031] In this advantageous embodiment, the releasing element and the blocking element cooperate not only to determine the time point of the axial displacement of the releasing element, but also to initiate a change in position of the blocking element.

[0032] In a further advantageous embodiment, the blocking element allows axial displacement of the release element along the guide rod when the second actuation lever moves away from the shaft.

[0033] In conjunction with the above-mentioned advantageous embodiment, a movement of the second actuating lever allows the movement of the release element away from the camshaft and allows the displacement of the release element along the guide rod, and a subsequent movement of the second actuating lever in the direction of the shaft initiates a change in the position of the shutoff element, whereby a particularly reliable switching process can be achieved.

[0034] In a further advantageous embodiment of the valve actuation device, the blocking element is attached to the second actuation lever, is pivotally mounted relative to the second actuation lever and actuates the shut-off element via a switching element, in particular a switching linkage or link guide element.

[0035] The pivotable mounting of the blocking element on the second actuating lever allows a particularly advantageous cooperation with a release element of the switching device: when the second actuating lever is pivoted in the direction of the camshaft, the blocking element can come into contact with the release element, which then pivots.

[0036] In a further advantageous embodiment of the valve actuation device, the release element has two actuation elements which are configured to change the position of the blocking element while the second actuation lever is moving in the shaft direction, such that the blocking element causes a change in position of the shutoff element.

[0037] In particular, the block element is thereby pivoted.

[0038] As already explained, it is preferably provided that movement of the second actuating lever away from the shaft causes movement of the release element and movement of the second actuating element towards the shaft causes pivoting of the blocking element.

[0039] In a further advantageous embodiment of the valve actuation device, the guide rod is oriented at least approximately parallel to the axis of rotation and / or the shaft.

[0040] This arrangement of the guide rods allows a particularly space-saving arrangement of the individual elements.

[0041] In a further advantageous embodiment of the valve actuation device, the release element can be pretensioned by means of at least one spring element against the blocking element along the guide rod when a change in position of the blocking element is to be made, and the release element can then be displaced along the guide rod when the blocking element releases the path by movement of the second actuation lever.

[0042] By pretensioning the guide rod, the actuation of the release element can be made independent of the actual moment of displacement, which makes it possible to create an operational relationship between the movement of the blocking element or the second actuating lever and the movement of the release element.

[0043] In a further advantageous embodiment of the valve actuator, the blocking element is configured as a rocker switch with a first connecting element, in particular a connecting head, the position of which changes when the blocking element is pivoted and which cooperates with a second connecting element, in particular a receiver, of the switching element.

[0044] In the present invention, the rocker switch is preferably formed as a kind of triangle or three-pronged star. The two points of the triangle are used to actuate the rocker switch, and the coupling head is located at the third corner / protrusion. The rocker switch with the coupling head offers a particularly simple mechanical release with respect to the blocking element.

[0045] In a further advantageous embodiment of the valve actuation device, the blocking element is rotatably attached to the second actuating lever and, in its first position, can cooperate with a second connecting element of the first actuating lever, in particular be brought into contact with the connecting element.

[0046] A rotatably mounted blocking element is a particularly simple and robust mechanical construction of a blocking element.

[0047] In a further advantageous embodiment of the valve actuation device, the axis of rotation of the shut-off element extends at least approximately parallel to the shaft.

[0048] The high degree of symmetry results in a particularly simple construction of the valve actuator.

[0049] In an advantageous embodiment of the valve actuation device, the first actuation lever and / or the second actuation lever are configured as a rocker lever or rocker arm.

[0050] In a further advantageous embodiment of the valve actuation device, the first actuating lever has a coupling part which surrounds the second actuating lever so as to form a stop for the second actuating lever and / or the coupling device and which limits the rotation of the second actuating lever around a common axis of rotation relative to the first actuating lever.

[0051] This allows a particularly advantageous type of force transmission from the first actuating lever to the second actuating lever to be achieved, and allows the valve actuating device to be designed in a particularly space-saving manner, in particular since all additional components on the second actuating lever can be provided at the location where the push rod of the first actuating lever is attached.

[0052] In a further advantageous embodiment of the valve actuation device, the flank of the second cam rises later than the flank of the first cam in relation to the direction of rotation under normal operating conditions of the shaft, and the contours of the first and second cams are formed such that the actuation movement of the second actuation lever produces a valve lift curve that is greater and longer in time than the valve lift curve produced by the actuation movement of the first actuation lever.

[0053] Because the first cam flank rises quickly, the relatively large force generated when the valve opens is applied to the first actuating lever, which is preferably constructed to have a high stiffness and therefore has greater strength than the second actuating lever, and in addition, the second actuating lever can be constructed with deliberately reduced stiffness, thereby saving weight and space.

[0054] The features and advantages discussed above in relation to the first aspect of the invention apply to the second aspect of the invention, and vice versa.

[0055] Further advantages and characteristics of the invention will become apparent from the following description and with reference to the non-limiting examples shown in the drawings, in which: FIG. [Brief description of the drawings]

[0056] [Figure 1] FIG. 2 is a top perspective view of a valve mechanism of an internal combustion engine. [Diagram 2] FIG. 2 is a top perspective view of an embodiment of a valve actuation system. [Diagram 3] FIG. 3 is a top view of two valve actuation levers of the valve actuation device according to FIG. 2; [Figure 4] FIG. 4 is a cross-sectional view of the valve actuator in plane II of FIG. 3; [Diagram 5] FIG. 2 is a top view of a mechanism for switching a valve actuator in a first position of a shutoff element. [Figure 6] FIG. 13 is a further top view of the mechanism for switching the valve actuator in a second position of the shutoff element. [Figure 7] FIG. 4 is a perspective view of a second actuating lever of the valve actuation device. [Figure 8a] 11A-11C are side views of a second valve operating lever and a second cam, each at different rotational positions of the cam. [Figure 8b] 11A-11C are top views of a switching element of a valve actuator in different positions. [Figure 8c] 13A-13D are top views showing enlarged details of the switching element in different positions. [Figure 9a] 11A-11C are side views of a second valve operating lever and a second cam, each at different rotational positions of the cam. [Figure 9b] 11A-11C are top views of a switching element of a valve actuator in different positions. [Figure 9c] 13A-13D are top views showing enlarged details of the switching element in different positions. [Figure 10a] 11A-11C are side views of a second valve operating lever and a second cam, each at different rotational positions of the cam. [Figure 10b]11A-11C are top views of a switching element of a valve actuator in different positions. [Figure 10c] 13A-13D are top views showing enlarged details of the switching element in different positions. [Figure 11a] 11A-11C are side views of a second valve operating lever and a second cam, each at different rotational positions of the cam. [Figure 11b] 11A-11C are top views of a switching element of a valve actuator in different positions. [Figure 11c] 13A-13D are top views showing enlarged details of the switching element in different positions. [Figure 12] 4A-4D are cross-sectional views of a release element in various loaded positions. [Figure 13] 4A-4D are cross-sectional views of a release element in various loaded positions. [Figure 14] FIG. 4 shows an example of two different valve lift curves that can be achieved with the valve actuation system according to FIG. 3. [Figure 15] 1 is a schematic diagram of an internal combustion engine according to the present invention; DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0057] Figure 1 shows a perspective view of the valve train of an internal combustion engine 101 with an embodiment of a valve actuation device 100. Figure 15 shows a schematic diagram of an internal combustion engine 101, which in the illustrated embodiment has four cylinders 102, each of which is provided with a valve actuation device 100. It will be appreciated that the solution according to the invention can also be applied to internal combustion engines 101 of different configurations, in particular with regard to the number of cylinders 102.

[0058] 1, a total of four valves are actuated, with the front two valves being actuated by the valve actuator 100 via a push rod 220. A first actuating lever 210 and a second actuating lever 211 of the valve actuator 100 pick up the valve actuation motion on cams 214, 215 respectively, which can then be transmitted to the valves.

[0059] Preferably, a reset device 96 is provided to ensure contact between the second actuating lever 211 and the second cam 215 when no load is applied to the second actuating lever 211 .

[0060] The embodiment of the valve actuation device 100 shown in Figure 1 is a so-called rocker arm and correspondingly has a receiver 97 for a pushrod 220 which transmits the valve actuation movement to at least one valve. However, the teachings described in connection with this embodiment are also transferable to other types of valve actuation devices, in particular rocker arms with rollers at the end or in the center of the rocker arm, and centrally mounted valve actuation levers, so-called rocker levers, with roll bar, slide rod or pushrod actuation.

[0061] FIG. 2 illustrates in perspective view an embodiment of a valve actuation system 100 configured to actuate a valve of an internal combustion engine, not shown in this figure.

[0062] The valve actuation device 100 comprises a first actuation lever 210 and a second actuation lever 211, which are preferably mounted for rotation about a common axis of rotation 213. A push rod 220 is connected to the first actuation lever 210, by which actuation motion is transmitted from the first actuation lever 210 or the second actuation lever 211 to the valve.

[0063] The first actuation lever 210 is configured to grip a contour of a first cam 214, and the second actuation lever 211 is configured to grip a contour of a second cam 215. The two cams 214, 215 are mounted non-rotatably on a shaft 216, in particular on a common shaft. Preferably, the first cam 214 has a different contour in the circumferential direction of the shaft 216 than the second cam 215.

[0064] The first actuating lever 210 and the second actuating lever 211 are connected to each other via a coupling device 10. In particular, the coupling device 10 is set up to transmit an actuating movement from the second actuating lever 211 to the first actuating lever 210 when the coupling device 10 is in a blocked state, or to convert the movement of the second actuating lever 211 into a so-called lost motion movement when the coupling device 10 is in a released state.

[0065] In the embodiment shown, the coupling device 10 is arranged on or is a component of the second actuating lever 211. Preferably, the longitudinal axis of the coupling device 10, along which the coupling device 10 is longitudinally displaceable, abuts tangentially to the path of the second actuating lever 211 around the axis of rotation.

[0066] In particular, the first actuating lever 210 has a coupling part 217 which preferably extends in the track of the second actuating lever 210. The coupling part 217 is connected, preferably by means of a screw, to a second coupling element 12 which can cooperate with the first coupling element 11 to transmit an actuating movement, as shown in FIG.

[0067] For switching, the coupling device 10 preferably has a blocking element 13b, which is preferably pivotable about an axis such that the coupling element 11, which is preferably part of the blocking element 13b and forms a stop 89 (not shown, see e.g. FIG. 4 or FIG. 7), is pivotable between at least two positions, said axis being distinct from the axis of rotation 213 of the actuating levers 210, 211 and which is preferably oriented parallel to the axis of rotation 213 and / or the camshaft and / or the guide rod 83.

[0068] In the coupled state, the first coupling element 11, which is attached to the first actuating lever 211 via the blocking element 13b, cooperates with the second connecting element 12 of the first actuating lever 210 in such a way that the valve actuation movement is transmitted from the first actuating lever 210 to the second actuating lever 211. In this case, the stop 89 of the first connecting element 11 comes into contact with the second connecting element. This position of the blocking element 13b is also referred to below as the first position or blocking position.

[0069] In contrast, in the released state of the coupling device 10, the blocking element 13b is in a second position (hereinafter also referred to as the released position) in which a stop 89 (not shown, see e.g. Fig. 4 or Fig. 7) of the first coupling element 11 does not cooperate with the second coupling element 12. Preferably, the blocking element 13b in Fig. 1 is pivoted by approximately 90° clockwise as will be explained in more detail below.

[0070] The shut-off element 13b is preferably actuated by a switching device 110 (not shown) whose members are preferably fixedly attached to the housing of the internal combustion engine whose valve is to be controlled (both not shown). The switching device 110 (not shown in FIG. 2) is preferably hydraulically or electromechanically operated by means of an actuator (not shown) and is further preferably controlled by the control unit (ECU) of the internal combustion engine.

[0071] FIG. 3 is a top view of the side facing away from the rotation axis 213 of the valve actuation device 100 of the embodiment shown in FIG.

[0072] 3, a first actuating lever 210 is shown. A solid arrow F indicates a direction from a first cam 214 to a push rod 220 on the first actuating lever 210 via a first pickup 218. 1 The force transmission, indicated by x, preferably extends substantially parallel to the direction of movement of the first actuation lever 210.

[0073] On the right side of Fig. 3, a second actuating lever 211 is shown. The force transmission from the second actuating lever 211 to the first actuating lever 210 only occurs when the coupling device 10 is in the blocked state. When the coupling device 10 is in the blocked state, a second force transmission path F from the second cam 215 through the second pickup 219 and the second actuating lever 210 to the coupling device 10 is not possible. 2 extends approximately parallel to the direction of movement of the second actuating lever 211. A second path F of force transmission extends from the coupling device 10. 2 extends, preferably via a connection 217 , in particular approximately perpendicular to the axis of movement of the second actuating lever 211 , to the first actuating lever 210 and to the push rod 220 .

[0074] From the above, route F 1 It is clear that in the illustrated embodiment, path F always works. 2 are selectively added depending on the state of the coupling device 10.

[0075] FIG. 4 is a cross-sectional view of an embodiment of a portion of the second actuating lever 211 and the first valve actuating lever 210 of the valve actuation device 100 in plane II of FIG.

[0076] As already partially described with reference to FIG. 2 and fully apparent in FIG. 4, the connecting device 10 has a first connecting element 11, a blocking element 13B with a pin 13A and additionally a second connecting element 12.

[0077] As already partially explained in connection with figure 2 and fully apparent in figure 4, the blocking element 13b and the first connecting element 11 are part of or attached to the second actuating lever 211. Furthermore, the coupling device 10 comprises a second connecting element 12, which is part of or attached to the first actuating lever 210.

[0078] In this case, the first connecting element 11 is force-transmittably fixed to the second actuating lever 211, and the second connecting element 12 is correspondingly force-transmittably fixed to the first actuating lever 210, preferably at its connecting part 217, and further preferably screwed in by means of a screw and fixed with a locking nut 221. In this case, the second connecting element 12 is preferably actuated via a stop 89 of the first connecting element 11. The cylinder bottom of the shut-off element 13b forming the stop 89 is preferably curved inwards, and the free end of the second connecting element 12 is preferably correspondingly curved convexly.

[0079] The shut-off element 13b is rotatably mounted on a second actuation lever 211 and can be actuated by a switching element 84, a switching linkage in the embodiment shown in Fig. 4. The switching linkage 84 can be actuated by a switching device 110. In this way, by means of the mechanical switching device 110 it is possible to selectively activate or deactivate a defined valve lift.

[0080] The switching device 110 preferably comprises a blocking element 112, which in the illustrated embodiment is configured as a rocker switch, and which comprises a first connecting element 118, in particular a dome head 118, which cooperates with a second connecting element 119, in particular a receiver, of the switching linkage 84.

[0081] In the embodiment shown, the blocking element 112 is mounted on a second actuating lever 211 so that it can pivot in the plane shown.

[0082] The switching device 110 further comprises a release element 111. The release element 111 is hydraulically or electromechanically operated by means of an actuator (not shown).

[0083] The release element 111 preferably has a first actuating element 116 and a second actuating element 117 (not visible in FIG. 4), which cooperate with the blocking element 112 to actuate the blocking element 13b, as described below with reference to FIGS. 5 and 6.

[0084] The valve actuating movement of the second actuating lever 211 is picked up by a second pickup 219 on the second cam 215. Correspondingly, the valve actuating movement of the first actuating lever 210 is picked up by a first pickup 218 on the second cam 215 (not shown in Figures 5 and 6). When the shut-off element 13b is in the first or blocking position, the actuating movement of the first actuating element 116 is transmitted to the first actuating lever 210.

[0085] 5, the shut-off element 13b is in a first position, also called the blocking position. Correspondingly, the coupling device 10 is in a blocking state, in which the valve actuation movement is transmitted from the second actuation lever 211 to the first actuation lever 210.

[0086] This first position is reached by the release element 111, which is displaceably mounted on a guide rod 83 fixed to the housing, being in such a position that the second actuating element 117 cooperates with the tip of the blocking element 112 configured as a rocker switch. This causes the coupling head 118 in FIG. 4 to pivot towards the left. The coupling head 118 cooperates with a receiving part 119 of the switching linkage 84, so that the switching linkage 84 also moves towards the left. The pin 13a of the blocking element 13b is received in a further receiving part of the switching linkage 84, so that the switching linkage 84 and the blocking element 13b cooperate in such a way that the first connecting element 11 is pivoted towards the right.

[0087] 6 shows the release state of the coupling device 10, with the blocking element 13b in the second or release position. In this case, the first coupling element does not cooperate with the second coupling element 12 of the coupling device 10, whereby the valve actuating movement of the second actuating lever 211 is not transmitted to the first actuating lever 210 and is therefore lost as a so-called lost motion.

[0088] In this case, the release element 111 of the switching device 110 has a position on the guide rod 83 such that the other end of the rocker switch 112 cooperates with the first actuating element 116 of the release element 111 in such a way that the rocker switch is pivoted towards the right. Via the coupling head 118 and the receiving part 119, this movement is transmitted to the switching linkage 84, which in turn transmits this movement via the pin 13a to the blocking element 13b, whereby the first coupling element 11 is pivoted towards the left.

[0089] In FIG. 7, the valve actuation device 100 is shown in a top perspective view and without the first actuation lever 210.

[0090] From said figure the position of the release element 111 with respect to the second actuating lever 211 and its first actuating element 116 and second actuating element 117 becomes clear.

[0091] As already explained with reference to Figures 5 and 6, the release element 111 is displaceably mounted on the guide rod 83. In the illustrated embodiment, the guide rod 83, which is fixedly mounted on the housing, is oriented parallel to a rotation axis 213, and the first actuating lever 210 and the second actuating lever 211 are mounted rotatably around the rotation axis 213. In this regard, the release element 111 can move between two guides (without reference numbers) of the guide rod 83.

[0092] 8-11 are diagrams clarifying the operational mode of the embodiment of the valve actuation system 100 shown in the figures.

[0093] The drawings marked with "a" (Figures 8a, 9a, 10a, 11a) each show a top view of the first valve lever 211 from the side where the first actuating lever 210 would be located in the complete valve actuation apparatus 100. The drawings marked with "b" (Figures 8b, 9b, 10b, 11b) each show the positions of the release element 111 corresponding to the switching states, and the drawings marked with "c" (Figures 8c, 9c, 10c, 11c) show details of the release element 111.

[0094] As already known from figures 4 to 7, the second actuating lever 211 comprises a switching device 110, which in particular comprises the members of the guide rod 83 and the release element 111. The release element 111 comprises a first actuating element 116 and a second actuating element 117, which cooperate with a rocker switch 112 acting as a blocking element (rocker switch 112 is not referenced in figures 7 to 11 as it is difficult to see).

[0095] Furthermore, the second actuating lever 211 has a blocking element 13b with the first connecting element 11, which are part of the coupling device 10. This allows the second actuating lever 211 to be connected to the first actuating lever 210.

[0096] A second pickup 219 (a wheel in the illustrated case) picks up the valve actuation motion on a second cam 215 .

[0097] In Fig. 8a the position of the second cam is such that, due to the direction of rotation of the camshaft, the cam lift is about to reach the second pickup 219. Due to the position of the shut-off element 13b or its first connecting element 11, the valve actuation movement is transmitted to the first actuation lever 210.

[0098] 8b is also a top view of the switching device 110 in a position in which it provides the first or blocking position of the blocking element 13b, where the release element 111 is arranged on the guide rod 83 such that its first actuating element 116 cooperates with one end of the rocker switch 112 to block the blocking element 13b in the first or blocking position.

[0099] 8c shows an enlarged view of the whole consisting of the guide rod 83 and the release element 111, where the area where the release element 111 surrounds the guide rod 83 or where the release element 111 is guided by the guide rod 83 is shown in cross section.

[0100] This allows one to see that the spring element 93 is located within the release element 111 and is held to the guide rod 83 by the first spring stop 98 and the second spring stop 99. In this regard, the spring stops 98, 99 are configured such that they can be displaced towards the spring as the guide rod moves, but are prevented from moving away from the spring.

[0101] In FIG. 9a, the lift of the second cam 215 is still before the second pickup, but is already somewhat closer due to the rotation of the camshaft.

[0102] This is followed by switching of the blocking element 13b from the first or blocking position to the second or releasing position.

[0103] For this, the guide rod 83 is moved towards the left, as shown by the hatched arrow in Figures 9b and 9c. This causes the rocker switch 112 to be pressed down by the second actuating element 117 of the release element 111. However, the rocker switch 112 does not change its position, so that one tip of the rocker switch 112 comes into contact with the first actuating element 116. Now, further displacement of the release element 111 on the guide rod 83 is prevented, as shown by the hatched arrow with a bar in Figure 9c. Nevertheless, if the guide rod 83 is displaced further, the spring element 93 of the release element 111 is compressed by the displacement of the second spring stop 99 towards the first spring stop 98.

[0104] In Fig. 10a, the lift of the cam 215 has reached the second pickup 219, so that the second actuating lever 211 pivots upwards. Since the blocking element 13b is in the blocking position, the first actuating lever 210 (not shown) now also pivots upwards.

[0105] By pivoting, the other extremity of the rocker switch 112 releases the first actuation element 116, as is evident in Fig. 10a by the dashed circle. This allows the release element 111 on the guide rod 83 to be displaced further to the left in Fig. 10b, which is brought about by the pretension of the spring element 93, which is itself relaxed. Correspondingly, the spring element 93 is shown in a relaxed state in Fig. 10c.

[0106] In Fig. 11a, the lift of the second cam 215 has already pivoted to a position such that the second actuating lever 211 pivots towards the base circle of the camshaft or cam 215. This pivoting movement brings the other tip of the rocker switch 112 into contact with the first actuating element 116 of the release element 111, causing the rocker switch 112 to pivot towards the right, as indicated by the arrow in Fig. 11a. This causes the blocking element 13b to pivot towards the left through the switching linkage 84 (not visible), also as indicated by the arrow in Fig. 11a. This causes the blocking element 13b to reach the second or release position.

[0107] Correspondingly, the blocking element 13b can be switched from the second or release position to the first or blocking position by manipulating the guide rod 83 towards the right. As shown in Fig. 11b, the release element 111 remains in its position and as shown in Fig. 11c, the spring element 93 remains relaxed.

[0108] 12 and 13 are cross-sectional views of the release element 111. It is clear that the first actuating element 116 and the second actuating element 117 of the release element 111 are also flexibly pretensioned by the spring elements 94 and 95. This allows the respective actuating elements 116, 117 to avoid contact with the rocker switch 112 if the rocker switch 112 or the blocking element cannot pivot (e.g. because it is blocked).

[0109] This is useful, for example, if the blocking element 13b is actually to be moved to the second or release position but is blocked on the first actuating lever 210, in particular on the second connecting element of the first actuating lever 210. The movement of the first actuating lever 210 can transmit forces to the first actuating element 116 that can cause damage.

[0110] In FIG. 13, actuating elements 116, 117 are each shown in a depressed position which they may assume in the event of an overload as described.

[0111] Figure 14 shows examples of two different valve lift curves that can be achieved using the valve actuation system, where the valve opening is shown as a function of crankshaft angle.

[0112] The valve lift curve IVC-480 belongs to the Miller cycle and, in the embodiment of the valve actuation device 100 shown in the previous figures, is caused by the first cam 214, thus the so-called Miller cam.

[0113] Miller operation of an internal combustion engine is particularly optimized in terms of consumption, but the cylinders are too lightly filled to start in Miller operation.

[0114] The valve lift curve IVC-580 belongs to another combustion cycle, in which the valves are open longer and the valve lift is 8.7 mm greater than in the illustrated Miller cycle. This valve lift curve IVC-580 is caused by the second cam 215. Thus, the valve lift curve IVC-580 covers the valve lift curve IVC-480.

[0115] As shown in Figure 14, the rise of the valve lift curve IVC-580 occurs later in time than the rise of the valve lift curve IVC-480. This ensures that the valve actuator 100 transmits most of the force generated when the valve opens through the sturdy and rigid first actuation lever 210 (force flow F 1 ). Only about one third of the force acts on the variable or adjustable actuation lever 211. It is therefore possible to design the actuation lever 211 with less stiffness and with smaller dimensions, especially in the width dimension.

[0116] Correspondingly, in the valve actuation device 100, the flank of the second cam 215 rises later than the flank of the first cam 214 with respect to the direction of rotation of the shaft 216 in normal operating conditions. This brings about the actuation movement of the first actuation lever 210 at a different time, preferably earlier, than the actuation movement of the second actuation lever 211. Internal combustion engines, in particular so-called large engines, are preferably operated in the Miller cycle for more than 90% of the operating time. The valve lift curve IVC-580 is preferably used only during start-up and temporary gliding (also called coasting).

[0117] It should be noted that the described embodiments are merely examples that are not intended to limit the scope of protection, application and configuration. Rather, the above description provides a guide for the skilled person to implement at least one embodiment, and various modifications can be made, in particular with respect to the function and arrangement of the described components, without departing from the scope of protection that is evident from the combination of the claims and their equivalent features. In particular, the valve actuation device may be a plunger or a rocker lever or a similar device. Furthermore, the switching device may have a different configuration, in particular according to the variants shown in US Pat. No. 5,399,633. Conversely, the switching device described with reference to the above figures may also be used in combination with an alternative coupling device, for example as shown in US Pat. No. 5,399,633. In this case, the switching device would actuate the link guide element, in particular via a switching link mechanism. [Explanation of symbols]

[0118] 10 Coupling device 11 First connecting element 12 Second connecting element 13A Pin 13B Blocking elements 83 Guide Rod 84 Switching element, switching link mechanism 85 Link, claw, U-shaped section 89 Stopper 93, 94, 95 Spring elements 96 Reset Device 97 Receptor 98 First spring stopper 99 Second spring stopper 100 Valve actuator 110 Switching Device 111 Release element 112 Block Elements 113 Switching window 114 Protective Spring 115 Release pin 116 First operating element 117 Secondary Operating Element 118 First connecting element 119 Second connecting element 210 First operating lever 211 Second operating lever 213 Rotational Axis 214 First Cam 215 Second Cam 216 Shaft 217 Connecting part 218 First Pickup 219 Second Pickup 220 Push rod 221 Lock nut F 1 First path of force transmission F 2 Secondary path of force transmission

Claims

1. A valve actuation system (100) for actuating at least one valve of a reciprocating engine, comprising: a first actuating lever (210) and a second actuating lever (211), said first actuating lever (210) and said second actuating lever (211) being mounted so as to be rotatable about a common axis of rotation (213), said first actuating lever (210) being connectable to at least one said valve so as to transmit an actuating motion to said at least one valve; a first cam (214) and a second cam (215), the first cam (214) and the second cam (215) being arranged on one shaft (216), the first actuating lever (210) gripping the contour of the first cam (214) and the second actuating lever (211) gripping the contour of the second cam (215); a mechanical coupling (10) capable of connecting the first actuating lever (210) and the second actuating lever (211) to each other, the mechanical coupling (10) having a blocking element (13B) movable to at least a first position and a second position, the mechanical coupling (10) being configured to transmit an actuating movement of the second actuating lever (211) to the first actuating lever (210) at least in the first position of the blocking element (13B); and a switching device (110) for moving the blocking element (13B) of the mechanical coupling device (10) at least from the first position to the second position and from the second position to the first position, the switching device (110) being configured such that a movement of the second actuation lever (211) mechanically causes a change in position of the blocking element (13B); A valve actuation system (100) having a

2. 2. The valve actuation device (100) of claim 1, wherein the switching device (110) comprises a release element (111) and a blocking element (112), the release element and the blocking element being configured to cooperate to block or allow axial displacement of the release element (111) along a guide rod (83) to which the release element (111) is axially displaceably mounted.

3. 3. The valve actuation device (100) of claim 2, wherein the guide rod (83) is fixed to a housing and is mounted to be axially displaceable to actuate the release element.

4. 4. The valve actuation device (100) of claim 2 or 3, wherein the release element (111) and the blocking element (112) mechanically cooperate to cause a change in position of the blocking element (13B) when the second actuating lever (211) moves in the direction of the shaft (216).

5. 5. The valve actuation device (100) of claim 2, wherein the blocking element (112) allows axial displacement of the release element (111) along the guide rod (83) when the second actuation lever (211) moves in a direction away from the shaft (216).

6. 6. The valve actuation device (100) according to claim 2, wherein the blocking element (112) is pivotally attached to the second actuation lever (211) relative to the second actuation lever and actuates the shutoff element (13B) through a switching element (84).

7. A valve actuation device (100) as described in claim 6, wherein the block element (112) is configured as a rocker switch having a first connecting element (118), the position of which changes when the block element (112) rotates and which cooperates with a second connecting element (119) of the switching element (84).

8. 8. A valve actuation device (100) according to any one of claims 2 to 7, wherein the release element (111) has two actuating elements (116, 117) configured to change the position of the blocking element (112) during movement of the second actuating lever (211) in the direction of the shaft (216), such that the blocking element (112) brings about a change in position of the shutoff element (13B).

9. 9. A valve actuation device (100) according to any one of claims 2 to 8, wherein the shut-off element (13B) cooperates with a second connecting element (12) of the first actuation lever (210) in a first position of the shut-off element.

10. 10. The valve actuation device (100) of claim 2, wherein the axis of rotation of the shutoff element (13B) extends parallel to the shaft (216), the guide rod (83) and / or the common axis of rotation (213).

11. The valve actuation device (100) of any one of claims 2 to 10, wherein the guide rod (83) is oriented parallel to the common axis of rotation (213) and / or the shaft (216).

12. 12. The valve actuation device (100) according to claim 2, wherein the release element (111) is capable of applying pretension to the blocking element (112) along the guide rod (83) by means of at least one spring element (93, 94) when the position of the blocking element (13B) is to be changed, and the release element (111) is then displaceable along the guide rod (83) when the blocking element (112) releases the path by movement of the second actuation lever (211).

13. The valve actuation device (100) of any one of claims 1 to 12, wherein the first actuation lever (210) and / or the second actuation lever (211) are configured as rocker levers or rocker arms.

14. 14. The valve actuation device (100) of any one of claims 1 to 13, wherein the first actuating lever (210) has a connection portion (217) that surrounds the second actuating lever (211) to form a stopper (89) for the second actuating lever (211) and / or the mechanical coupling device (10), the stopper limiting the rotation of the second actuating lever (211) around a common axis of rotation (213) relative to the first actuating lever (210).

15. 15. A valve actuation device (100) according to any one of claims 1 to 14, wherein the side of the second cam (215) rises later than the side of the first cam (214) with respect to the direction of rotation of the shaft (216) under normal operating conditions, and the contours of the first cam (214) and the second cam (215) are formed such that the actuation movement of the second actuation lever (211) produces a valve lift curve (IVC-580) that is greater and longer in time than the valve lift curve (IVC-480) produced by the actuation movement of the first actuation lever (210).

16. An internal combustion engine (101) comprising at least one valve actuation device (100) according to any one of the preceding claims.

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