Variable valve gear with independent control of multiple inlet valves

Abstract

The invention relates to a variable valve gear (200) for an internal combustion engine, having a plurality of valve groups (7-1, 7-2) with inlet and outlet valves (70-1, 70-2; 78-1; 78-2). The valve gear (200) comprises an outlet valve actuation system (5), having a common outlet valve actuation shaft (520) for actuating the outlet valves (78-1, 78-2), and separate inlet valve actuation systems (2-1, 2-2) for actuating the inlet valves (70-1, 70-2) of each valve group (7-1, 7-2). Each inlet valve actuation system (2-1, 2-2) has its own pivoting frame (80-1, 80-2), the pivoting frames being pivotal independently of one another, and the outlet valve actuation shaft (520) is rotationally coupled to the inlet valve actuation systems (2-1, 2-2).

Description

Variable valve train with independent control of multiple intake valves The present invention relates to the field of internal combustion engines. In particular, the invention relates to a variable valve train for actuating a valve of an internal combustion engine. Variable valve trains are known in the art. Such variable valve trains allow the adjustment (change) of a valve lift, i.e., a parameter characterizing the valve lift profile, such as the lift height (maximum height of the valve opening within an engine cycle), duration, and / or phase of the valve opening relative to the engine cycle. A variable valve train allows the lift height to be adjusted, for example, depending on a number of driving parameters (e.g., engine speed) and a throttle input (e.g., position of a throttle lever or pedal). A particularly advantageous variable valve train is known from DE 10 2005 057 127 Al (hereinafter: DE' 127). In particular, DE' 127 shows the valve train depicted in Figs. 1-3. In this train, the position of the valve crank axis 14 can be changed by pivoting a pivoting frame 80 in order to adjust the valve lift. Another advantageous valve train is described in DE 10 2016 101 657 Al (hereinafter: DE' 657). The object of the present invention is to provide a valve train and an internal combustion engine with at least some of the advantages of the solutions described in DE 127 and DE 657, which additionally allows for advantageous yet simple valve control for multiple cylinders. The control system is intended to enable simple, reliable, and at the same time versatile control of the internal combustion engine. Summary of the invention The problem is solved by the variable valve train according to claim 1. The variable valve train according to one aspect of the invention is provided for an internal combustion engine, wherein the internal combustion engine has a first valve group with at least one first intake valve and at least one first exhaust valve and a second valve group with at least one second intake valve and at least one The valve train comprises a first exhaust valve actuation system with an exhaust valve actuation shaft driven (directly or indirectly) by a crankshaft of the internal combustion engine, at least one first exhaust valve actuation element driven by the exhaust valve actuation shaft for actuating the at least one first exhaust valve, and at least one second exhaust valve actuation element driven by the exhaust valve actuation shaft for actuating the at least one second exhaust valve. The valve train further comprises a first intake valve actuation system with a first valve actuation mechanism for actuating the at least one first intake valve and with a (e.g.,A first intake valve actuation system with a first pivoting frame mounted (e.g., in the cylinder head) pivotable about a pivot axis, wherein pivoting the first pivoting frame adjusts the valve lift for the at least one first valve; and a second intake valve actuation system with a second valve actuation gear for actuating the at least one second intake valve and with a second pivoting frame mounted (e.g., in the cylinder head) pivotable about a pivot axis, wherein pivoting the second pivoting frame adjusts the valve lift for the at least one second valve. The first and second pivoting frames are independently pivotable. The exhaust valve actuation shaft is rotaryally coupled to the first intake valve actuation system (in particular to its first valve actuation gear) and to the second intake valve actuation system (in particular to its second valve actuation gear).Further actuation systems, for example for additional valves, are not excluded. This valve train offers several advantages, including a simple, cost-effective, and space-saving design, while still allowing for highly variable actuation of the intake valves across multiple valve groups. This advantage is largely due to the fact that the exhaust valves are actuated by a common exhaust valve actuation system, while the intake valves are actuated by separate intake valve actuation systems with independently pivoting swashplates. This independent pivoting enables flexible valve control adapted to specific requirements. For example, under low load, one (or more) cylinders can be effectively deactivated by moving the corresponding swashplate to a position for reduced valve lift, while the combustion engine continues to operate independently with one (or more) other cylinder(s).Since the valve control is designed to adjust the valve lift of at least the intake valves, energy losses due to the actuation of unused valves are also minimal in this case. This and other options for fuel-efficient control of the combustion engine are thus made available. Furthermore, it is possible to manufacture various engine variants with different numbers of cylinders using a large number of identical modular components, thereby reducing complexity in development, manufacturing, spare parts storage, and maintenance. Furthermore, the additional advantages mentioned in DE 127 and DE 657 can be at least partially achieved. The present invention is a further development (improvement) of the subject matter disclosed in those documents. The valve train according to the invention can be used particularly advantageously in internal combustion engines with at least two cylinders in devices or vehicles with high engine speeds, for example in motorcycles. It can also be used, for example, in passenger cars, trucks, aircraft or watercraft. Further advantages, features, aspects and details of the invention, as well as preferred embodiments and special aspects of the invention, will become apparent from the dependent claims, the description and the figures. Brief description of the characters Exemplary embodiments of the invention are shown in the figures and are described in more detail below. The figures show: Figs. 1-3 show views of a valve train known from DE' 127; Fig. 4 shows a view of a valve train known from DE'657; Fig. 5 shows diagrammatically the valve lift as a function of the actuator deflection of the pivot actuator of the valve train known from DE'657; Figs. 6a-6c show perspective views of a valve train according to the invention; Fig. 7 shows a frontal cross-sectional view of the valve train from Figs. 6a-6c; and Fig. 8 shows an enlarged detail of the valve train from Fig. 7. Detailed description of and embodiments General information on the valve train (Figs. 1-3) A valve train 2 is described below with reference to Figures 1-3. Figures 1-3 are identical to those in DE 127, and the parts shown are also described therein. The valve train 2, or parts thereof, can be used as part of the present invention (not fully shown in Figures 1-3), as described below. The valve train 2 shown in Figs. 1-3 comprises a drive system 10 and a transmission (or gearbox) 4. The drive system 10 provides a rotary motion. This rotary motion preferably occurs synchronously with the engine cycle of the internal combustion engine, so that one full rotation corresponds to one complete engine cycle, and is particularly preferably driven by the crankshaft of the internal combustion engine 1. The gearbox 4 converts the rotary motion of the drive system into a stroke motion for actuating the valve 70. Actuating the valve here refers to a stroke motion of the valve 70 that opens or closes the valve 70, preferably synchronously with the engine cycle. The drive system 10 comprises a drive gear 22, a valve crank gear 12, and a valve crank 16 (also referred to as the first drive element). The drive gear 22 is mounted stationary in the cylinder head and rotatably about a drive axis 24. As shown in Fig. 3, the drive gear 22 can be driven by a sprocket 26 driven by the engine crankshaft. Alternatively (not shown in Fig. 3), the drive gear can also be driven in another way, for example by a camshaft gear of the exhaust camshaft of the exhaust actuation system 5. In this case, the exhaust camshaft can be driven by a sprocket 26 driven by the engine crankshaft, analogous to the arrangement shown later in Figs. 6a-6c with an exhaust valve actuation shaft 520 driven by a sprocket 526. The valve crank gear 12 is rigidly connected to the valve crank 16. The valve crank 16 and the valve crank gear 12 are rotatably mounted about a valve crank axis 14 (also referred to as the first axis of rotation). More precisely, the valve crank 16 is rotatably mounted about the valve crank axis 14 by a valve crank bearing 15, which connects the valve crank 16 to a rigid pivot frame 80 described below. Here and in the following, the term "axis" refers to a geometric axis or an axis of rotation. The mounting of the valve crank 16 is not shown in Fig. 1. The drive gear 22 is driven by a crankshaft of the internal combustion engine 1. The drive is synchronous with the engine cycle, i.e., one full revolution of the drive gear 22 corresponds to one engine cycle. In a four-stroke engine, this is the case when the gear ratio between the crankshaft and the drive gear 2 is 1:1. The drive gear 22 meshes with the valve crank gear 12. The gear ratio between the drive gear 22 and the valve crank gear 12 is 1:1. Thus, the valve crank gear is also driven synchronously with the engine cycle. In the valve train shown in Fig. 1, the position of the valve crankshaft 14 can be changed. The mechanism for this is shown in more detail in Figs. 2-3. In addition to the elements shown in Fig. 1, a pivoting frame 80 (also referred to as a bearing body) is visible. The pivoting frame 80 is rigid and, in this example, consists of several rigidly connected parts. It is pivotally mounted on the cylinder head 3 (on a pivot shaft) about the pivot axis, which is identical to the drive axis 24 shown in Fig. 1. Furthermore, the valve crank 16 is mounted in the pivoting frame 80, so that pivoting the pivoting frame 80 causes the valve crankshaft 14 to pivot, i.e., a change in the position of the valve crankshaft 14 along a circular path about the pivot axis 24. This change in the position of the valve crankshaft 14 serves, as described below, to adjust the valve lift. Because the pivot axis 24 and the drive axis are identical, it is ensured that the position of the valve crank axis 14 remains on a circular segment around the drive axis 24 in every pivot position of the pivot frame 80. This ensures that the valve crank gear 12, which is rotatably mounted around the valve crank axis 14, and the drive gear 22 remain engaged in every pivot position of the pivot frame 80. The pivoting frame 80 can be held in a fixed position or pivoted by means of a pivoting drive. An exemplary pivoting drive 84 is shown in Figs. 2-3 and described in DE 127. The pivoting drive 84 comprises a toothed segment 84a rigidly connected to the pivoting frame 80, into which a gear 84b engages. A further detail of the pivoting drive 84 is shown in Fig. 3: A worm gear 84c engages with the gear 84b and serves to rotate it. This provides a transmission manufactured from the worm gear 84c to the swivel frame with constant transmission ratio. The pivoting mechanism, including its drive, and the pivoting frame 80 are also referred to herein as the actuation system. More generally, the actuation system is understood to encompass all parts that serve to set and maintain the position of the first valve crankshaft 14. Further parts of the valve train that serve to periodically open and close the valve are also referred to as the actuation system. More precisely, Figures 1 to 3 show an intake actuation system for actuating the intake valve 70; and Figure 3 additionally shows a further exhaust actuation system 5, designed as a conventional camshaft, for actuating the exhaust valve 78. The valve train according to the invention (as illustrated in Figs. 6a-6c, 7, 8 and described below) comprises (at least) two intake actuation systems with independently pivotable pivot frames. These intake actuation systems can each be designed like the intake actuation systems shown in Figs. 1-4. With this proviso, the description of the valve train in Figs. 1-4 applies accordingly to the valve train according to the invention and, in particular, to its intake actuation systems. The following describes some general (but not mandatory) aspects of the invention, which are illustrated in Fig. 1-3 and explained with reference numerals given therein, but which can also be realized independently of the embodiment of Fig. 1-3 in connection with any other aspects of the invention. According to one aspect, the valve train is located in the area of ​​the cylinder head of the internal combustion engine. According to another aspect, the valve train (in particular the intake actuation system, more precisely the intake gearbox) further comprises a connecting rod 30 with a first connecting rod joint 34 and a second connecting rod joint 36, and a guide element 60 for guiding the connecting rod, wherein the guide element is pivotable about a guide axis 66 (by being pivotably mounted on a guide element shaft). According to yet another aspect, the connecting rod 30 is articulated at its first connecting rod joint 34 to the first drive element (and the valve crank) 16. According to yet another aspect, the connecting rod 30 is articulated at its second connecting rod joint 36 to the guide element 60. According to another aspect, a second drive element 22 of the valve train is provided to drive the first drive element 16. The second drive element 22 is rotatable about a second axis of rotation 24. According to another aspect, the second drive element 22 is a second drive gear. The valve train includes a first drive gear 12 for driving the first drive element 16, wherein the first drive gear 12 is rotatable about the first axis of rotation 14. According to another aspect, a push element (rocker arm) 40 is attached to the guide element 60. According to another aspect, the push element 40 is a roller. According to another aspect, the valve train 1 includes a transmission element 50 in releasable mechanical contact with the push element 40. According to another aspect, the transmission element 50 is in mechanical contact with the push element 40 along a contact surface (rocker arm contour) 54 in order to transmit a force exerted by the push element 40 to the valve 70. According to another aspect, the transmission element 50 is biased towards the valve 70 by a force element 58. According to another aspect, the internal combustion engine 1 includes a fixed stop 57 to define a maximum deflection of the transmission element 50. According to another aspect, the transmission element 50 is a lever that is pivotable about a lever axis 52. According to another aspect, the lever 50 is single-armed. According to yet another aspect, a movement of the pressure element 40 in the direction of the lever axis 52 causes the valve to open. According to another aspect, valve 70 is an intake valve. According to yet another aspect, the internal combustion engine further comprises a second intake valve 70', which is preferably also operated by the valve train. According to another aspect, changing the position of the first axis of rotation 14 alters the valve lift (a quantity characterizing the valve lift profile). According to another aspect, the quantity characterizing the valve lift profile is the lift height and / or the valve opening duration. According to yet another aspect, changing the position of the first axis of rotation 14 alters the phase relationship between the rotation angle of the first drive element 16 and the engine cycle. According to another aspect, the push element 40 is guided on a guide track 68, and the guide track 68 of the push element 40 can be changed by changing the position of the first rotation axis 14. According to another aspect, changing the position of the first rotation axis 14 is a pivoting of the first rotation axis 14 about a pivot axis 24. According to another aspect, the connecting rod is 30 links and the guide element is 60 links of a planar rotary joint chain. According to another aspect, valve 70 is an inlet valve, and the second actuator also operates an outlet valve 78. According to another aspect, the maximum stroke height of the valve 70 is at least 5mm. A general aspect of the invention is that the valve train 2 comprises a planar linkage with four links or a four-link rotary joint chain. The joints preferably comprise the drive shaft 24, the guide shaft 66, the first connecting rod joint 34, and the second connecting rod joint 36. All elements of the rotary joint chain described above are positively connected to one another. A general aspect of the invention is that the valve train 2 is arranged in the region of the cylinder head of the internal combustion engine. An arrangement in the region of the cylinder head means that the valve crank 16 is fundamentally (i.e., in at least one possible position of the axis of rotation 14 or in at least one pivot position of a pivot frame 80, as shown, for example, in Fig. 3) mounted on the cylinder head side with respect to the interface between the engine block and the cylinder head. Even if a cylinder head and an engine block are not clearly distinguishable in the internal combustion engine, such an interface can, for example, be defined by an area defined by the piston crown of the reciprocating piston, with the reciprocating piston at top dead center.According to this characterization, the valve train 2 corresponds to an overhead camshaft valve train, wherein the valve crank 16 corresponds to the camshaft. Therefore, according to one aspect, the use of the valve train according to the invention as an overhead camshaft valve train for an internal combustion engine, as well as an internal combustion engine with the valve train according to the invention with an overhead camshaft, is proposed. This arrangement also enables an encapsulated design of the valve train, in which the parts of the valve train are arranged within an encapsulation. The valve train 2 can be divided into an active subsystem and a passive subsystem according to one aspect. The active subsystem can be characterized by the fact that the state of motion of the active subsystem is essentially determined by the state of motion of the valve crank 16, i.e., by a rotation angle of the valve crank 16 and by the position of the valve crank axis 14, or by positive engagement with the The passive subsystem is connected to the valve crank 16. The passive subsystem is connected to the active subsystem by force transmission, in particular by means of the valve spring 72. For further details on Figures 1-3, reference is made to DE 127, the complete content of which is hereby incorporated into the present description by reference. In particular, reference is made to paragraphs

[0144] -

[0159] as well as the other passages of DE 127 cited therein, which are hereby incorporated by reference. In particular, all aspects of a valve train or internal combustion engine described in DE 127, insofar as they are additionally equipped with the pivoting drive described herein, are considered to belong to the present invention. Swivel gearbox with variable transmission ratio (Fig, 4) In the following, with reference to Fig. 4, a further valve train is described, the design of which is also applicable to the valve train according to the invention and, in particular, to its intake actuation systems. Corresponding parts are designated with the same reference numerals as in Figs. 1-3, even though some geometric details have been changed. The description of Figs. 1-3, as well as the description in DE 127, applies accordingly (especially to the actuation system) to this embodiment, unless otherwise shown in the figures or in the following. In particular, the valve train shown in Fig. 4 has a pivoting frame 80 in which the valve crank (first drive element) 16 is rotatably mounted about the axis of rotation 14. By pivoting the pivoting frame 80, as also shown in Figs. 1-3, the position of the first axis of rotation 14 can be changed, thereby adjusting the valve lift, more precisely the lift height, of the valve 70. Instead of the pivoting drive 84 or 84a-84d shown in Figs. 1-3 for pivoting the pivoting frame 80, the valve train shown in Fig. 4 comprises the pivoting drive 90 described below. The pivoting drive 90 is equipped to pivot the pivoting frame 80 about the pivot axis 24 or to hold it in its position as required, and thus to control the valve lift of the valve 70. The pivoting drive 90 comprises an electric actuator (pivot actuator) 92 and a pivoting gearbox 94. The pivoting gearbox 94 transmits a rotary movement of the actuator shaft into a pivoting movement of the pivoting frame 80. The swivel gear 94 comprises the following elements from the input to the output side: a worm gear 98a, a rotatable drive body 94a, and a coupling rod 94b. The axis of rotation 86 of the drive body 94a coincides with the lever axis of the rocker arm 50 (see Fig. 2), which simplifies the design, reduces costs, and increases stability. The worm gear 98a comprises an adjustable worm 98 and a toothed segment on the outer contour of the drive body 94a. The adjustable worm 98 is rotatable about its axis and is driven by the actuator 92. The coupling rod 94b is articulated between the drive body 94a and the swivel frame 80 in order to transmit a rotation of the drive body 94a into a swiveling movement of the swivel frame 80. The drive body 94a, the coupling rod 94b, and the pivot frame 80 thus form a linkage mechanism (together with a stationary, i.e., non-rotating, frame, formed, for example, by the cylinder head), more precisely a four-bar linkage. Even more precisely, the four-bar linkage thus formed is a double rocker arm, wherein the drive body 94a forms a crank, the coupling rod 94b a link, and the pivot frame 80 a rocker arm of the double rocker arm. The stroke height of the inlet valve 70 is set by the pivot position of the pivot frame 80: The drive body 94a and the coupling rod 94b are coupled to each other in such a way that the lever arm 96 formed by the drive body 94a relative to the coupling rod 94b is larger in a pivot frame deflection with a small stroke height than in a pivot frame deflection with a larger stroke height, i.e. the lever arm 96 is larger at a small stroke height. This change in the lever arm 96 contributes significantly to the non-constant transmission ratio of the swivel gear 94 described herein (ratio of differential swivel frame deflection of the 80 swivel frame to differential actuator deflection of the swivel actuator 92), as described in more detail in DE'657 to Fig. 4a-5. Therefore, a general aspect of the invention is that the lever arm formed by the drive body relative to the coupling rod is larger at low stroke heights than at high stroke heights, i.e., it decreases with increasing stroke height – preferably monotonically. According to a further aspect, the lever arm is larger at the first pivot frame deflection than at the second pivot frame deflection. Another aspect is that the lever arm during the first pivot frame deflection is at least 2 times, preferably at least 4 times, larger than during the second pivot frame deflection. It is also a general aspect of the invention that the transmission ratio of the swivel mechanism decreases with increasing stroke height – preferably monotonically. According to a further aspect, the transmission ratio is greater at the first swivel frame deflection (low stroke height, preferably less than 20% of the maximum stroke height) than at the second swivel frame deflection (greater stroke height, preferably more than 50% or even 80% of the maximum stroke height). According to a further aspect, the transmission ratio at the first swivel frame deflection is greater by a factor of at least 2, preferably by a factor of at least 4, than at the second swivel frame deflection. According to another aspect, the pivoting drive 94 comprises a drive body 94a rotatable about a third axis of rotation, which includes a toothed segment curved about the third axis of rotation and engaged with the adjusting worm 98. According to yet another aspect, the third axis of rotation 86 simultaneously forms the lever axis 52 of the rocker arm 50. According to another aspect, the swivel drive 94 allows the first rotation axis 14 to be adjusted (swiveled) by swiveling or holding the swivel frame 80. Fig. 5 diagrammatically shows the stroke height of the valve 70 as a function of the actuator deflection of the rotary actuator 92 (number of revolutions of the actuator shaft). The solid line represents the stroke height for the valve train according to the invention with a variable transmission ratio shown in Fig. 4. For comparison, the dashed line shows the stroke height for an otherwise analogous valve train with a rotary drive and a constant transmission ratio, as exemplified in Fig. 3. The dashed line also shows a non-linearly increasing stroke height with an initially shallow and then increasing slope. This characteristic is primarily due to the design of the rocker arm contour 54, and not to the (constant) transmission ratio of the rotary drive. A comparison of the two curves shown in Fig. 5 clearly shows that in the valve train according to the invention (solid line), the initial slope is increased at low valve lift, but is more limited at higher valve lift. This is due to the effect of the rocker arm contour design. The strong conditional nonlinearity (dashed curve) is at least partially compensated, resulting in reduced fluctuations in the slope of this curve. Consequently, the rotary actuator described herein leads to more stable and balanced valve train behavior. Finally, further general aspects relating to the variable-ratio rotary valve train are described: According to one aspect, the valve train has an actuation system for the periodic opening and closing of one (i.e., at least one) valve. The actuation system comprises a (particularly rigid) rotary frame pivotally mounted about a pivot axis (e.g., in the cylinder head); a first drive element rotatably mounted about a first axis of rotation in the rotary frame; and a valve actuation gear for transmitting the rotational motion of the first drive element into a stroke motion for actuating the valve such that when the position of the first axis of rotation changes due to the pivoting of the rotary frame, a stroke height (optionally also one or more other aspects of the valve stroke, i.e., further quantities characterizing the valve stroke, such as a phase of the valve stroke profile) for the valve is adjusted.The valve train further includes a pivoting drive for pivoting the pivoting frame around the pivoting axis with a pivoting actuator and a pivoting gearbox (between the pivoting actuator and the pivoting frame). In general terms, the rotary drive comprises a worm gear, a rotatable drive body driven by the rotary actuator via the worm gear, and a connecting rod arranged between the drive body and the rotary frame. The rotary drive has a non-constant transmission ratio. The transmission ratio is defined as the ratio of the differential deflection of the rotary frame to the differential deflection of the rotary actuator; non-constant means that the transmission ratio varies, in particular, depending on the actuator deflection of the rotary actuator. Preferably, the transmission ratio depends on the actuator deflection (e.g., total rotation angle from the minimum position) of the rotary actuator in such a way that the transmission ratio is lower for a first rotary frame deflection associated with a smaller stroke height (e.g.,The swivel angle of the swivel frame (from minimum position) is greater than the translation ratio for a second swivel frame deflection assigned to a larger stroke height. For further details on Fig. 4-5, reference is made to DE'657, the complete content of which is hereby incorporated into the present description by reference. embodiment of the invention In the following, a valve train 200 according to an embodiment of the invention is described with reference to Figures 6a-6c, 7, and 8. Figures 6a-6c show the valve train 200 in perspective views from different angles; Figure 7 shows the valve train 200 of Figures 6a-6c in a sectional view through a section plane corresponding to the section plane AA shown in Figure 4; and Figure 8 shows an enlarged view of the sectional view of Figure 7. The reference numerals in Fig. 6a-8 correspond to those of the illustrative examples shown in Fig. 1-4, and the description of the corresponding elements from Fig. 1-4 is also applicable to Fig. 6a-8, unless otherwise shown herein. The valve train 200 is designed for a two-cylinder engine, wherein a first valve group 7-1 is assigned to a first cylinder and a second valve group 7-2 to a second cylinder of the internal combustion engine. The invention is not limited to two cylinders and can be extended to any number of additional cylinders. The first valve group 7-1 comprises two intake valves 70-1 and two exhaust valves 78-1, and the second valve group 7-2 comprises two intake valves 70-2 and two exhaust valves 78-2, the invention being generalizable to any number of intake and exhaust valves per valve group. The exhaust valves 78-1 and 78-2 of the different valve groups 7-1, 7-2 are actuated by a common exhaust valve actuation system 5 of the valve train 200. The exhaust valve actuation system 5 comprises a camshaft (exhaust valve actuation shaft) 520, and for each of the exhaust valves 78-1, 78-2, a respective cam (first and second exhaust valve actuation element, respectively, driven by the exhaust valve actuation shaft) 5-1, 5-2 arranged on the camshaft for actuating the respective exhaust valve 78-1, 78-2. The camshaft 520 is driven by a crankshaft of the internal combustion engine. This drive is achieved by means of a chain sprocket 526 attached to the camshaft 520, which is driven by a timing chain 530 through the crankshaft (not (shown) is driven. Other parts of the valve train 2 are also indirectly driven by this rotation of the chain sprocket 526, as described below. Alternatively, the camshaft 520 can also be driven indirectly by attaching the chain sprocket to another element that drives the camshaft 520. For example, the chain sprocket can alternatively be attached to one of the drive gears 22-1 or 22-2 described below, so that the corresponding drive gear 22-1 or 22-2 drives the camshaft 520, analogous to the drive of the camshaft by means of the drive gear 22 driven by the chain sprocket 26 in Fig. 3. The exhaust valve actuation system 5 can also be designed analogously to the corresponding exhaust valve actuation system shown in Fig. 3 or 4 in other respects. In a further variation, in addition to or instead of the cams 5-1 and 5-2, other known first or second exhaust valve actuation elements, such as a desmodromic valve or snap-action levers, can be used to actuate the exhaust valves 78-1 and 78-2. According to a general aspect, a single (rigid) exhaust valve actuating shaft 520 (more precisely the respective exhaust valve actuating elements 5-1, 5-2 driven by the exhaust valve actuating shaft 520) drives the exhaust valves 78-1, 78-2 of the different valve groups 7-1, 7-2. Furthermore, in one aspect, the exhaust valve actuation system 5 with the exhaust valve actuation shaft 520 has co-rotating (attached) first and second exhaust actuation shaft gears 512-1, 512-2, which are rotaryally coupled to the first and second intake valve actuation systems 2-1, 2-2 (details see below). The intake valves 70-1 and 70-2 of the different valve groups 7-1 and 7-2 are actuated by their own intake valve actuation systems 2-1 and 2-2 of the valve train 200. Intake valve actuation systems 2-1 and 2-2 each have their own valve actuation gearboxes 4-1 and 4-2. These gearboxes are independently adjustable to allow for independent adjustment of the valve lift of intake valve actuation systems 2-1 and 2-2, respectively. The inlet valve actuation systems 2-1 and 2-2 are each analogous to the inlet valve actuation systems shown in Fig. 1-4 (with drive system 10, Transmission system or gearbox 4 and swivel frame 80 or their components) constructed, unless otherwise specified below, and unless otherwise specified, the above description (and reference numerals) of this inlet valve- Actuating systems are also applicable to the present invention, wherein in Figs. 6a-8 the reference numerals of the parts of the inlet valve actuating systems 2-1 and 2-2 are each provided with the suffix -1 and -2, respectively. The parts and functions of the first inlet valve actuating system 2-1 are also described in more detail below, and the analogous description applies accordingly to the second inlet valve actuating system 2-2 (whereby the corresponding reference numerals then bear the suffix -2 instead of -1, and the elements are designated as "second" instead of "first") and, if applicable, to further inlet valve actuating systems. The inlet valve actuation systems 2-1 and 2-2 are driven by their respective first and second drive systems 10-1 and 10-2, which provide rotational movements. These rotational movements are converted into periodic valve actuations by the respective valve actuation gears 4-1 and 4-2. The drive systems 10-1 and 10-2 (and thus also the valve actuation gears 4-1, 4-2) are rotaryally coupled to the exhaust actuation shaft 520. This ensures that the two intake valve actuation systems 2-1 and 2-2 always execute coordinated rotational movements. Preferably, both drive systems 10-1 and 10-2 are driven by the exhaust actuation shaft 520. The first drive system 10-1 is described in more detail below with reference to Figures 6a-6c. The first drive system 10-1 comprises a first drive gear 22-1, which is rotatable about a drive axis 24. The first drive gear 22-1 is rotaryally coupled to the exhaust valve actuating shaft 520. More precisely, the exhaust valve actuating system 5 has a first exhaust actuating shaft gear 512-1 that rotates with (and is attached to) the exhaust valve actuating shaft 520, and the first exhaust actuating shaft gear 512-1 is rotaryally coupled to the first drive gear 22-1. This coupling is achieved in Figs. 6a-6c by the first drive gear 22-1 engaging with the first exhaust actuating shaft gear 512-1 of the exhaust valve actuating system 5. Similarly, a second exhaust actuating shaft gear 512-2 of the exhaust valve actuating system 5 is rotaryally coupled to the second drive gear 22-2. This arrangement illustrates a general possible aspect of the valve train having a chain sprocket 526 (particularly rotating with the exhaust valve actuating shaft) for driving the exhaust valve actuating shaft 520 by a chain, wherein the The first exhaust actuating shaft gear 512-1 is arranged to drive the first valve actuating gear 4-1; and the second exhaust actuating shaft gear 512-2 is arranged to drive the second valve actuating gear 4-2. In the embodiment shown in Figs. 6a-6c, the first and second drive systems 10-1 and 10-2 are driven by the exhaust valve actuation system 5 (which is in turn driven by the chain gear 526). More precisely, the drive gears 22-1 and 22-2 are driven by the first and second exhaust actuation shaft gears 512-1 and 512-2, respectively. Furthermore, the first intake valve actuation system 2-1 is constructed analogously to the intake valve actuation system 2 shown in Fig. 1-4. For example, the first drive system 10-1 also includes a first valve crank 16-1. The first valve crank 16-1 is rotatably mounted about a first valve crank axis 14-1. The first valve crank 16-1 has a first valve crank gear 12-1 that is rotaryally coupled to (approximately meshed with) the first drive gear 22-1. The first valve crank 16-1 is driven by the first drive gear 22-1 via this coupling. The first inlet valve actuation system 2-1 further comprises a first valve actuation gear 4-1 for actuating the at least one first inlet valve 70-1 (by converting the rotational movement of the first drive system, more precisely the valve crank 16-1, into a preferably reciprocal actuating movement for actuating the first valve 70-1) and a pivotably mounted first pivot frame 80-1. By pivoting the first pivot frame 80-1, a valve lift for the at least one first valve 70-1 can be adjusted. This adjustment is effected by mounting the first valve crank 16-1 in the first pivoting frame 80-1, so that pivoting the first pivoting frame 80-1 causes the position of the first valve crank axis 14-1 to pivot (along a circular path around the drive axis 24). To pivot the first pivoting frame 80-1 (and thus to adjust the valve lift for the first valve 70-1), the first inlet valve actuation system 2-1 comprises a first pivoting drive 90-1. The first pivoting drive 90-1 includes a first actuator 92-1 and a first pivoting gear 94-1 for transmitting a movement of the first actuator 92-1 into a pivoting movement of the first pivoting frame 80-1. The second inlet valve actuation system 2-2 is constructed analogously to the first inlet valve actuation system 2-1 and has a second valve actuation gear 4-2 for actuating at least one second inlet valve 70-2 and a pivotable The second pivoting frame 80-2 is mounted on bearings. By pivoting the second pivoting frame 80-2, the valve stroke for the at least one second valve 70-2 can be adjusted. The statements made regarding the first inlet valve actuation system 2-1 (or the inlet valve actuation system 2 of Fig. 1-4) also apply analogously to the second inlet valve actuation system 2-2. The first and second rotary actuators 90-1 and 90-2 can be controlled independently of each other, thus enabling independent adjustment of valve strokes for the first and second valves 70-1 and 70-2. The first and second pivot frames 80-1, 80-2 are pivotably mounted about a common pivot axis (which, in the illustrated embodiment, coincides with the drive axis 24). The first and second inlet valve actuation systems 2-1 and 2-2 (and in particular their drive systems 10-1, 10-2, valve actuation gears 4-1, 4-2, and / or pivot frames 80-1, 80-2) are arranged adjacent to one another in the axial direction of the exhaust valve actuation shaft 520, as can be seen in particular in Fig. 7 and its enlargement Fig. 8. In this arrangement, the first inlet valve actuation system 2-1, or its aforementioned part(s), is opposite a first partial longitudinal section of the exhaust valve actuation shaft 520 (whereby the exhaust valve actuation shaft 520, not visible in Fig. 7, extends over the width of Fig. 7 and the first longitudinal section is the left half of Fig. 7), and the second inlet valve actuation system 2-2, or its aforementioned part(s), is opposite a first partial longitudinal section of the exhaust valve actuation shaft 520 (where the exhaust valve actuation shaft 520, not visible in Fig. 7, extends over the width of Fig. 7 and the first longitudinal section is the left half of Fig. 7), and the second inlet valve actuation system 2-2 is opposite a first partial longitudinal section of the exhaust valve actuation shaft 520 (where the exhaust valve actuation shaft 520, not visible in Fig. 7, extends over the width of Fig. 7 and the first longitudinal section is the left half of Fig. 7).the above-mentioned part(s) is opposite a second part longitudinal section (right half of Fig. 7) of the exhaust valve actuating shaft 520, which is adjacent to the first part longitudinal section. As can be seen in particular in Figs. 7 and 8, the first and second inlet valve actuation systems 2-1 and 2-2 (and in particular their drive systems 10-1, 10-2, valve actuation gears 4-1, 4-2, and / or pivot frames 80-1, 80-2) are each arranged on opposite sides of a central plane (perpendicular and transverse to the plane of Figs. 7 and 8). The first and second exhaust actuation shaft gears 512-1, 512-2 are arranged on opposite sides of the first and second partial longitudinal sections (i.e., in Figs. 6a-6c, at the lateral edges of the valve train 200), and the axial distance between the first and second exhaust actuation shaft gears 512-1, 512-2 corresponds to the full width of the valve train 200, i.e., the entire summed axial extent of the first and second inlet valve actuation systems 2-1 and 2-2 (or of their valve actuation gears 4-1, 4-2). Here, “one” is to be understood as “at least one”. For example, the term “one first inlet valve 70-1” (to be understood as “at least one first inlet valve 70-1”) also includes two first inlet valves 70-1, as is also shown in the embodiment of Figs. 6a-6c and 7 (with two first and second inlet valves 70-1, 70-2 each and two first and second exhaust valves 78-1 and 78-2 each per valve group). Similarly, the invention is not limited to two valve groups, but can also include a third, fourth, etc., valve group with associated further exhaust valve actuating elements and an associated third intake valve actuating system. The actuating system applicable to the first and second intake valves is then analogous to the third and any further intake valve actuating systems. In particular, the internal combustion engine can further comprise a third valve group with at least one third intake valve and at least one third exhaust valve. The exhaust valve actuation system 5 can then further comprise at least one third exhaust valve actuating element driven by the exhaust valve actuating shaft 520 for actuating the at least one third exhaust valve. The valve train can then further comprise a third intake valve actuation system with a third valve actuating gear for actuating the at least one third intake valve and with a pivotably mounted third pivoting frame, wherein pivoting the third pivoting frame adjusts the valve lift for the at least one third valve. In this case, the first, second, and third pivoting frames are independently pivotable; and the exhaust valve actuating shaft 520 is rotaryally coupled to the first, second, and third valve actuating gears. In summary, according to one aspect of the invention, a variable valve train 200 for an internal combustion engine with multiple valve groups 7-1, 7-2 with intake and exhaust valves 70-1, 70-2; 78-1; 78-2 is provided. The valve train 200 comprises an exhaust valve actuation system 5 with a common exhaust valve actuation shaft 520 for actuating the exhaust valves 78-1, 78-2, and separate intake valve actuation systems 2-1, 2-2 for actuating the intake valves 70-1, 70-2 of the respective valve group 7-1, 7-2. The intake valve actuation systems 2-1, 2-2 each have their own independently pivotable pivot frames 80-1, 80-2. The exhaust valve actuation shaft 520 is rotaryally connected to the first and second intake valves. Actuating systems 2-1, 2-2 (especially to their first and second drive systems 10-1, 10-2 and / or to their valve actuating gears 4-1, 4-2) coupled. Oil lubrication Furthermore, the valve train of Figures 6a-6c, 7 and 8 can be equipped with the lubrication supply system described in WO 2020 / 058200 Al. In particular, as shown in greater detail in WO 2020 / 058200 Al, the lubrication supply system can have a pivot frame lubrication supply channel for each of the first and second pivot frames 80-1 and 80-2, which leads from the pivot shaft through the respective pivot frame 80-1 or 80-2 to the valve crankshaft bearing. The lubricant supply system may also have a lubricant outlet from the Swivel frames 80-2 or 80-2. This lubricant outlet can, in particular, be an intermittent lubricant outlet for the intermittent release of lubricant and / or release the lubricant from the interior of the swivel frame 80-1 or 80-2 into a pressureless volume. The valve train and internal combustion engine described here can be configured particularly advantageously for use in a motorcycle engine. From one perspective, the internal combustion engine described herein is therefore a motorcycle engine. From another perspective, a motorcycle equipped with such an internal combustion engine is provided.

Claims

Claims:

1. Variable valve train (200) for an internal combustion engine, the internal combustion engine comprising a first valve group (7-1) with at least one first inlet valve (70-1) and at least one first exhaust valve (78-1) and a second valve group (7-2) with at least one second inlet valve (70-2) and at least one second exhaust valve (78-2), the valve train comprising: an exhaust valve actuation system (5) with an exhaust valve actuation shaft (520) driven by a crankshaft of the internal combustion engine, at least one first exhaust valve actuation element (5-1) driven by the exhaust valve actuation shaft (520) for actuating the at least one first exhaust valve (78-1), and at least one second exhaust valve actuation element (5-2) driven by the exhaust valve actuation shaft (520) for actuating the at least one second exhaust valve (78-2);a first inlet valve actuation system (2-1) with a first valve actuation gear (4-1) for actuating the at least one first inlet valve (70-1) and with a pivotably mounted first pivoting frame (80-1), wherein pivoting the first pivoting frame (80-1) adjusts the valve lift for the at least one first valve (70-1); and a second inlet valve actuation system (2-2) with a second valve actuation gear (4-2) for actuating the at least one second inlet valve (70-2) and with a pivotably mounted second pivoting frame (80-2), wherein pivoting the second pivoting frame (80-2) adjusts the valve lift for the at least one second valve (70-2), wherein the first and second pivoting frames (80-1, 80-2) are pivotable independently of each other, and wherein; the exhaust valve actuation shaft (520) is rotaryally coupled to the first inlet valve actuation system (2-1) and to the second inlet valve actuation system (2-2).

2. Variable valve train (200) according to claim 1, further comprising a first pivoting drive (90-1) for pivoting the first pivoting frame (80-1) and a second pivoting drive (90-2) that can be controlled independently of the first pivoting drive (90-1) for pivoting the second pivoting frame (80-2).

3. Variable valve train (200) according to the preceding claim, wherein the first pivoting drive (90-1) comprises a first actuator (92-1) and a first pivoting gear (94-1) for transmitting a movement of the first actuator (92- 1) in a pivoting movement of the first pivoting frame (80-1), and wherein the second pivoting drive (90-2) has a second actuator (92-2) and a second pivoting gearbox (94-2) for transmitting a movement of the second actuator (92- 2) exhibits a pivoting movement of the second pivoting frame (80-2).

4. Variable valve train (200) according to one of the preceding claims, wherein the exhaust valve actuating shaft (520) is a camshaft and the first and second exhaust valve actuating elements (5-1, 5-2) are cams arranged on the camshaft.

5. Variable valve train (200) according to one of the preceding claims, wherein the exhaust valve actuation system (5) further comprises: a first exhaust actuation shaft gear (512-1) rotating with the exhaust valve actuation shaft (520), wherein the first exhaust actuation shaft gear (512-1) is rotationally coupled to the first intake valve actuation system (2-1), in particular to the first valve actuation gear (4-1); and a second exhaust valve actuating shaft gear (512-2) rotating with the exhaust valve actuating shaft (520), wherein the second exhaust valve actuating shaft gear (512-2) is rotaryally coupled to the second inlet valve actuating system (2-2), in particular to the second valve actuating gear (4-2).

6. Variable valve train (200) according to the preceding claim, wherein the first inlet valve actuation system (2-1) comprises a first drive system (10-1) with a first drive gear (22-1), wherein the first drive gear (22-1) is rotatable about a drive axis (24) and engages in the first exhaust actuation shaft gear (512-1) of the exhaust valve actuation system (5), and wherein the second inlet valve actuation system (2-2) comprises a second drive system (10-2) with a second drive gear (22-2), wherein the second drive gear (22-2) is rotatable about the drive axis (24) and engages in the second exhaust actuation shaft gear (512-2) of the exhaust valve actuation system (5).

7. Variable valve train (200) according to the preceding claim, wherein the first and second pivot frames (80-1, 80-2) are pivotably mounted about the drive axis (24).

8. Variable valve train (200) according to one of the preceding two claims, wherein the first drive system (10-1) comprises a first valve crank (16-1), wherein a) the first valve crank (16-1) is rotatably mounted about a first valve crank axis (14-1); b) the first valve crank (16-1) is driven by a first valve crank gear (12-1) engaging with the first drive gear (22-1); and / or c) the first valve crank (16-1) is mounted in the first pivot frame (80-1) such that pivoting the first pivot frame (80-1) causes the position of the first valve crank axis (14-1) to pivot; and wherein the second drive system (10-2) has a second valve crank (16-2), wherein d) the second valve crank (16-2) is rotatably mounted about a second valve crank axis (14-2); e) the second valve crank (16-2) is driven by a second valve crank gear (12-2) engaging with the second drive gear (22-2); and / or f) the second valve crank (16-2) is mounted in the second pivot frame (80-2) such that pivoting the second pivot frame (80-2) causes the position of the second valve crank axis (14-2) to pivot.

9. Variable valve train (200) according to one of the preceding four claims, wherein the first and second exhaust actuating shaft gears (512-1, 512-2) are arranged on opposite sides of the first and second partial longitudinal sections, and the axial distance between the first and second exhaust actuating shaft gears (512-1, 512-2) is greater than the axial extent of the first and / or second intake valve actuating system (2-1, 2-2).

10. Variable valve train (200) according to one of the preceding claims, wherein the first and second inlet valve actuation systems (2-1, 2-2) are arranged adjacent to each other in the axial direction of the exhaust valve actuation shaft (520), such that the first inlet valve actuation system (2-1) is opposite a first partial longitudinal section of the exhaust valve actuation shaft (520), and the second inlet valve actuation system (2-2) is opposite a second partial longitudinal section of the exhaust valve actuation shaft (520) adjacent to the first partial longitudinal section.

11. Variable valve train (200) according to one of the preceding claims, wherein the first and second inlet valve actuation systems (2-1, 2-2) are arranged on opposite sides of a central plane perpendicular to the axis of the exhaust valve actuation shaft (520).

12. Variable valve train (200) according to one of the preceding claims, wherein the first and second valve groups (7-1, 7-2) are assigned to two different cylinders of the internal combustion engine.

13. Variable valve train (200) according to one of the preceding claims, wherein the internal combustion engine further comprises a third valve group with at least one third inlet valve and at least one third exhaust valve, and wherein the exhaust valve actuation system (5) further comprises at least one third exhaust valve actuation element driven by the exhaust valve actuation shaft (520) for actuating the at least one third exhaust valve, and wherein the valve train further comprises a third inlet valve actuation system with a third valve actuation gear for actuating the at least one third inlet valve and with a pivotably mounted third pivoting frame, wherein pivoting the third pivoting frame adjusts the valve lift for the at least one third valve, wherein the first, second, and third pivoting frames are pivotable independently of one another, and wherein the exhaust valve actuation shaft (520) is rotationally connected to the first,The second and third valve actuation gears are coupled.

14. Internal combustion engine with a first cylinder and a second cylinder and the variable valve train (200) according to one of the preceding claims, wherein the first valve group is assigned to the first cylinder and the second valve group is assigned to the second cylinder.

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