Valve actuation system for providing valve actuation motion for intake valve delayed / early closing and internal EGR

Abstract

The valve actuation system comprises a first motion transmission mechanism operably connected to a first valve actuation motion source that provides at least main valve actuation to at least one intake engine valve. A second motion transmission mechanism is operably connected to a second valve actuation motion source that provides at least LIVC and IEGR valve actuation. When a selectable coupling mechanism is operated in a first state, main valve actuation is transmitted to at least one intake engine valve via the first motion transmission mechanism. When the selectable coupling mechanism is operated in a second state, at least a portion of the main valve actuation is transmitted again to at least one intake engine valve, and LIVC and IEGR valve actuation is transmitted to at least one intake engine valve via the second motion transmission mechanism, the coupling mechanism, and the first motion transmission mechanism.

Description

Technical Field

[0001] The present disclosure generally relates to a valve actuation system for use in an internal combustion engine, and more particularly to a valve actuation system for providing valve actuation for intake valve late / early closing and internal exhaust gas recirculation.

Background Art

[0002] Valve actuation in an internal combustion engine is required for the engine to operate. Typically, the valve actuation force for opening an engine valve (i.e., an intake, exhaust, or auxiliary engine valve) is transmitted by a valve train, and such valve actuation force can be provided by a primary motion source and / or an auxiliary motion source. As used herein, the description "primary" refers to the so-called principal engine valve motion, i.e., the valve motion used during the generation of the positive output in which fuel is burned in the engine cylinder to provide the net output of the engine output, while the description "auxiliary" refers to other engine valve motions (e.g., compression release brake, bleeder brake, cylinder decompression, cylinder cut-off, brake gas recirculation (BGR), etc.) intended to replace the generation of the positive output, or engine valve motions (e.g., internal exhaust gas recirculation (IEGR), variable valve actuation (VVA), early exhaust valve opening (EEVO), early intake valve opening (EIVC), late intake valve closing (LIVC), swirl control, etc.) intended to be added to the generation of the positive output.

[0003] In many internal combustion engines, the primary and / or auxiliary sources of motion may be provided by a fixed-profile cam, more specifically by one or more fixed lobes or bumps, each of which may be an integral part of the cam. The ability to vary the timing and lift of the intake and / or exhaust valves can yield benefits such as improved performance, better fuel economy, reduced emissions, and enhanced vehicle drivability. However, the use of a fixed-profile cam can make it difficult to adjust the timing and / or amount of engine valve lift to optimize them for various engine operating conditions.

[0004] Assuming a fixed cam profile, one method of adjusting valve timing and lift was to provide a “lost motion” or variable-length device in the valve train linkage between a given engine valve and its corresponding cam. Lost motion is a term applied to the field of technical solutions to modify the valve motion defined by the cam profile by a variable-length mechanical, hydraulic, or other linkage assembly. In a lost motion system, the cam lobe can provide the “maximum” motion (longest dwell and maximum lift) required over the entire range of engine operating conditions, including positive power-generating and / or auxiliary motions, as may be required (even if assisting primary or auxiliary motion). A variable-length system may then be incorporated into the valve train linkage between the valve to be opened and the cam providing maximum motion, in order to reduce or eliminate some or all of the motion given to the valve by the cam. Typically, such a lost motion device is controllable between an “extended,” “locked” state, i.e., a motion-transmitting state, and a “retracted,” “unlocked” state, i.e., a motion-absorbing state. During motion transmission, the lost motion device is maintained in a substantially rigid configuration (with play for lash adjustment) so that the valve actuation motion applied to it is transmitted to the corresponding engine valve. On the other hand, during motion absorption, the lost motion device can absorb or avoid, i.e., "eliminate," at least a portion (including up to all) of the valve actuation motion applied to it, thereby preventing such valve actuation motion from being transmitted to the corresponding engine valve.

[0005] Valve actuation systems incorporating lost-motion functionality continue to be developed to provide better valve actuation performance and flexibility. However, increased cost, packaging, and size are often determinants of the desirability of such engine valve actuation systems. Valve actuation systems with lost-motion components that overcome these limitations while still providing a variety of valve actuation performance and flexibility would represent a welcome advance in the field.

[0006] A valve actuation system that can provide a combination of auxiliary valve actuation movements, such as IEGR combined with LIVC or EIVC, in addition to the main valve actuation movement, in a reliable and cost-effective manner would be a welcome addition to the field. [Overview of the project]

[0007] This disclosure describes various embodiments of a valve actuation system for acting on at least one engine valve in an internal combustion engine.

[0008] In a first embodiment, such a system comprises a first valve actuation motion source and a first motion transmission mechanism operably connected to at least one intake engine valve, wherein the first valve actuation motion source is configured to provide at least main valve actuation motion. A second motion transmission mechanism is operably connected to a second valve actuation motion source, which is configured to provide at least intake valve closing (LIVC) valve actuation motion, which is slower than the main valve actuation motion, and internal exhaust gas recirculation (IEGR) valve actuation motion. A selectable coupling mechanism is disposed between the first and second motion transmission mechanisms. When the selectable coupling mechanism is operated in a first state, the main valve actuation motion is transmitted to at least one intake engine valve via the first motion transmission mechanism. When the selectable coupling mechanism is operated in the second state, at least a portion of the main valve actuation motion is transmitted to at least one intake engine valve via the first motion transmission mechanism, and the LIVC valve actuation motion and the IEGR valve actuation motion are transmitted to at least one intake engine valve via the second motion transmission mechanism, the coupling mechanism, and the first motion transmission mechanism.

[0009] In a second embodiment, such a system comprises a first valve actuation motion source and a first motion transmission mechanism operably connected to at least one intake engine valve, the first valve actuation motion source providing at least intake valve early closing (EIVC) valve actuation motion. A second motion transmission mechanism is operably connected to a second valve actuation motion source, the second valve actuation motion source configured to provide at least main valve actuation motion and internal exhaust gas recirculation (IEGR) valve actuation motion. A selectable coupling mechanism is disposed between the first and second motion transmission mechanisms. When the selectable coupling mechanism is operated in a first state, the EIVC valve actuation motion provided by the first valve actuation motion source is transmitted to at least one intake engine valve via the first motion transmission mechanism. When the selectable coupling mechanism is operated in the second state, at least a portion of the EIVC valve actuation motion is transmitted to at least one intake engine valve via the first motion transmission mechanism, and the main valve actuation motion and IEGR are transmitted to at least one intake engine valve via the second motion transmission mechanism, the coupling mechanism, and the first motion transmission mechanism.

[0010] In both the first and second embodiments, the selectable coupling mechanism may comprise a selectable hydraulic actuator, which is retracted during a first state and extended during a second state. Alternatively, the selectable coupling mechanism may comprise a selectable mechanical locking mechanism, which is unlocked during a first state and locked during a second state.

[0011] In the first embodiment, when the selectable coupling mechanism is operated in the second state, a handoff from the main valve actuation motion to the LIVC valve actuation motion may occur. Similarly, in the second embodiment, when the selectable coupling mechanism is operated in the second state, a handoff from the EIVC valve actuation motion to the main intake valve actuation motion may occur.

[0012] In both the first and second embodiments, the IEGR valve actuation motion does not cause a handoff with the main valve actuation motion or the EIVC valve actuation motion, respectively.

[0013] Methods corresponding to the first and second embodiments will also be described. [Brief explanation of the drawing]

[0014] The aforementioned and other features and advantages will be discussed in detail in the following non-limiting description of specific embodiments, along with the accompanying drawings. [Figure 1] This is a schematic diagram of an internal combustion engine equipped with a valve actuation system according to the present disclosure. [Figure 2] This is a perspective view of a first valve actuation system that may be used to implement the technology described herein. [Figure 3] This is a perspective view of a second valve actuation system that may be used to implement the technology described herein. [Figure 4] This graph shows a typical valve lift profile, particularly an intake valve lift profile, according to the first embodiment of this disclosure. [Figure 5] This is a flowchart illustrating the operation of the system according to the first embodiment of this disclosure. [Figure 6] This graph shows a typical valve lift profile, particularly an intake valve lift profile, according to a second embodiment of the present disclosure. [Figure 7] This is a flowchart illustrating the operation of the system according to the second embodiment of this disclosure. [Modes for carrying out the invention]

[0015] As used herein, the term “operably connected” is understood to mean a functional relationship between at least two components, i.e., the claimed components must be connected to perform the indicated function (potentially including the presence of intervening elements or components).

[0016] A schematic diagram of an internal combustion engine 100 comprising the valve actuation system 101 according to this disclosure is shown with reference to Figure 1. The valve actuation system 101 comprises a first motion transmission mechanism 104 operably connected to a first valve actuation motion source 102 and configured to receive first valve actuation motion from the first valve actuation motion source 102. The first motion transmission mechanism 104 is also operably connected to one or more engine valves 106 (associated with cylinders 108 of the internal combustion engine 100) and configured to transmit the first valve actuation motion to at least one engine valve 106. As further shown, the valve actuation system 101 also comprises a second motion transmission mechanism 110 operably connected to a second valve actuation motion source 112 and configured to receive second valve actuation motion from the second valve actuation motion source 112. A selectable coupling mechanism 114 is provided, which allows for a selectable coupling of the second motion transmission mechanism 110 to the first motion transmission mechanism 104 under the control of a control system 116, so that a second valve acting motion can be applied to at least one engine valve 106 via the second motion transmission mechanism 110, the selectable coupling mechanism 114, and the first motion transmission mechanism 104.

[0017] As is known in the art, the engine valve 108 may comprise either an intake valve or an exhaust valve, and in one embodiment, a separate valve actuation system 101 may provide separately for different engine valve types associated with a single cylinder, for example, one instance of the valve actuation system 101 for the intake valve of cylinder 108, and another instance of the valve actuation system 101 for the exhaust valve of cylinder 108. For simplicity of explanation, Figure 1 shows a single cylinder 108, but it will be understood that the internal combustion engine 100 may comprise, and typically would comprise, two or more such cylinders. Furthermore, the implementation of the valve actuation motion sources 102, 112 and the motion transmission mechanisms 104, 110 may vary as is known in the art. For example, the first and second motion transmission mechanisms 104, 110 may comprise a type III (center pivot) rocker arm equipped with a cam roller or tappet and operably connected to the corresponding cam. Alternatively, if the motion sources 102, 112 are provided by one or more overhead cams, the first and second motion transmission mechanisms 104, 110 may comprise type II (end pivot) finger followers equipped with cam rollers that contact the corresponding overhead cams. In various embodiments, the selectable coupling mechanism 114 may comprise a hydraulically operated unidirectional coupling mechanism that allows valve actuation motion applied to the second motion transmission mechanism 110 to be selectively transmitted to the first motion transmission mechanism 104, but does not allow valve actuation motion applied to the first motion transmission mechanism 104 to be transmitted to the second motion transmission mechanism 110. Furthermore, if the coupling mechanism 114 is hydraulically controlled, the control system 114 that controls the operating state of the coupling mechanism 114 may comprise a suitable engine control unit (ECU) also known in the art that communicates with one or more solenoid valves known in the art. In this case, the ECU can control the solenoid valve to supply working fluid to the coupling mechanism or to restrict the flow of working fluid to the coupling mechanism, thereby controlling the operating state of the coupling mechanism.

[0018] Implementations of the valve actuation system 100 may be found in U.S. Patent No. 7,392,772 ("'772 Patent"), and Figure 2 illustrates the system described in the '772 Patent. As shown in Figure 2, the first / main rocker arm 200 is provided to transmit main valve events, e.g., main exhaust or intake valve events received from a first valve actuation motion source (in this case, a cam) 202. In this embodiment, the coupling mechanism 114 is integrated within the first / main rocker arm 200, i.e., the first rocker arm 200 also includes a laterally extending boss 204 that houses a coupling mechanism in the form of a hydraulically actuated actuator 206 controlled via a control valve, as is known in the art. Alternatively, the coupling mechanism may include a hydraulically actuated mechanical locking mechanism as known in the art (e.g., as taught in U.S. Patent No. 9,790,824), which can be controlled to be locked or motion-transmitting, or unlocked or motion-absorbing. The system in Figure 2 further comprises a second / auxiliary rocker arm 210 aligned to receive valve actuation motion from a second valve actuation motion source (again, a cam) 212. The second rocker arm 210 is also aligned with a boss 204 extending from the first rocker arm 200. A spring 214 is provided to bring the second rocker arm 210 into contact with the second valve actuation motion source 212 and bias it away from the boss 204, which is located at the motion-applying end of the second rocker arm 200, and a lash adjustment screw 216, such that lash or clearance space is provided between the boss 204 and the lash adjustment screw 216. During operation in the main event mode of the engine, the actuator 206 retracts into the boss 204, thereby maintaining lash between the first and second rocker arms 200, 210. In this way, the second valve actuation motion provided by the second valve actuation motion source 212 is not transmitted from the second rocker arm 210 to the first rocker arm 200, that is, the second valve actuation motion is "lost".On the other hand, if it is desired to add an auxiliary / second valve actuation motion to the first valve actuation motion, the actuator 206 is hydraulically controlled to eliminate the lash space so that the second rocker arm 210 extends from the boss 204 and contacts the actuator 206, thereby transmitting the second valve actuation motion to the first rocker arm 200.

[0019] Figure 3 illustrates another example of a valve actuation system suitable for implementing the system illustrated in Figure 1. In particular, the illustrated valve actuation system substantially follows the teachings of Patent No. 772, wherein the system comprises a first / main rocker arm 300 and a second / auxiliary rocker arm 302. In this embodiment, as shown in Figure 3, the first rocker arm 300 contacts the valve bridge 320 at its motion-giving end. Furthermore, the first and second rocker arms 300, 302 each include their respective roller followers (not shown) disposed at their motion-receiving ends, which receive valve actuation motion from their respective first and second valve actuation motion sources, which in this case again are implemented as cams on a camshaft (not shown). Similar to the embodiments described above from the '772 patent, the first and second rocker arms 300, 302 have a hydraulically operated actuator (or a hydraulically operated mechanical locking mechanism as described above) 306 which can be controlled to either a retracted position in which valve actuation motion is not transmitted from the second rocker arm 302 to the first rocker arm 300, or an extended position in which valve actuation motion is transmitted from the second rocker arm 302 to the first rocker arm 300. However, unlike the embodiment illustrated in Figure 2, the actuator 306 is not housed in the first rocker arm 300, but is housed in a boss 304 formed at the motion-giving end of the second rocker arm 302. To receive valve actuation motion from the actuator 306, the first rocker arm 300 includes a lateral extension 312 aligned with the boss 304 and the actuator 306.

[0020] As described above, systems of the type illustrated in FIGS. 2 and 3 can be used to implement a valve actuation system according to the present disclosure, specifically to implement a combination of IEGR, LIVC, and EIVC valve actuation operations. As taught in U.S. Patent No. 11,131,222, LIVC valve actuation can be provided in a manner in which the first and second valve actuation motions cooperate with each other, i.e., the valve actuation motions provided by separate motion sources overlap to provide a single desired valve event, in contrast to separate substantially non-overlapping valve events provided by separate motion sources. Stated another way, separate valve actuation motion sources cooperate with each other, or provide a handoff as used herein, such that the valve actuation motion provided by the second valve actuation motion source can take over control of the actuation of the engine valve at a time when the first valve actuation motion source has already provided non-zero lift to the engine valve, or vice versa. In this way, the second valve actuation motion source can add valve actuation motion to the main valve event without requiring a separate event discrete from the main event, and can change the timing, lift, or duration of the main valve event.

[0021] In a first embodiment, the valve actuation system illustrated in FIGS. 1 - 3 is configured to provide both IEGR valve actuation motion and LIVC valve actuation motion to engine valve 106 in addition to main intake valve actuation motion. This is achieved by having a first valve actuation motion source 102 configured to provide at least the main intake valve actuation motion (see FIG. 1, which is also applicable to the systems of FIGS. 2 and 3), and a second valve actuation motion source 112 configured to provide at least LIVC valve actuation motion relative to the first valve actuation motion and to provide a so-called IEGR pre-bump valve actuation motion. Still further, in some embodiments, the LIVC valve actuation motion is configured to establish a handoff with the main valve actuation motion, as will be described in more detail below.

[0022] Figure 4 illustrates embodiments of valve actuation motion provided by the first and second valve actuation motion sources according to this disclosure. In particular, Figure 4 illustrates valve lift (actuation) for both exhaust valves (curves shown in thin lines) and intake valves (curves shown in thick lines). Furthermore, the various intake-related lift curves are further distinguished in that the valve actuation motion provided by the first valve actuation motion source 102 is illustrated by a solid line, and the valve actuation motion provided by the second valve actuation motion source 112 is illustrated by a dashed line. Under this understanding, Figure 4 illustrates valve actuation motion including the main exhaust valve actuation motion 402 and the main intake valve actuation motion 404. Using the type of valve actuation system illustrated in Figures 1 to 3, the main intake valve action motion 404 is provided by the first valve actuation motion source, while the second valve actuation motion source provides the IEGR valve actuation motion 406 and the LIVC valve actuation motion 408. As shown in the figure, the IEGR valve actuation motion 406 of one or more intake valves is provided simultaneously with the main exhaust valve actuation motion 402, thereby facilitating exhaust gas recirculation, as is known in the art. Furthermore, as described above, the LIVC valve actuation motion 408 is configured such that a handoff 410 occurs between the main intake valve actuation motion 404 and the LIVC valve actuation motion 408, in this example near the peak lift point during the opening phase of the main intake valve actuation motion 404. As will be understood by those skilled in the art, a specific handoff point 410 is illustrated, but various other handoff points, for example during the closing phase of the main intake valve actuation motion 404, may be adopted as a design choice. Nevertheless, as shown in the figure, the LIVC valve actuation motion 408 provides a slower intake valve closing compared to the first or main intake valve actuation motion 404.

[0023] Based on the valve operation example illustrated in FIG. 4, a method of operating an engine valve will be described with reference to FIG. 5. In practice, the method illustrated in FIG. 5 may be implemented using, for example, the controller 116 as illustrated in FIG. 1. Starting from block 502, a determination is made as to whether the requirement to operate the engine is in a first state or a second state. Such a determination may be made based on an input provided by a user, such as a vehicle driver, according to known techniques (e.g., a user-selectable switch operably communicating with the controller 116). Alternatively, such a determination may be based on the detection of specific operating conditions (e.g., engine speed, engine torque, torque demand, aftertreatment temperature status, etc.) using sensors communicating with the controller 116, as is known in the art. As used herein, the first and second states referred to refer to the operating states of the selectable coupling mechanism 114, the first state corresponding to the operation of the selectable coupling mechanism 114 in the retracted / unlocked / energy-absorbing state, and the second state corresponding to the operation of the selectable coupling mechanism 114 in the extended / locked / energy-transmitting state.

[0024] In block 502, if it is determined that operation should continue according to the first state, the process proceeds to block 504, where, as described above, the selectable coupling mechanism 114 is maintained in or switched to its retracted / unlocked / energy-absorbing state. In the first state, according to this embodiment, at least one engine valve is operated according to the main intake valve operation 404 as transmitted by the first motion transmission mechanism 104, while the valve operating motion is not transmitted to at least one engine valve via the second motion transmission mechanism 110. The processes of steps 502 and 504 are continuously repeated as long as engine operation according to the first state is desired or until a switch to the second operating state is detected.

[0025] If it is determined in block 502 that a second operating state is desired, the process proceeds to block 506, where the selectable coupling mechanism 114 is maintained in its extended / locked / motion transmission state or switched to that state. In the second state, according to this embodiment, at least one engine valve is again actuated according to at least a portion of the main intake valve actuation 404 (i.e., that portion of the main intake valve actuation 404 that occurs before the handoff 410) as transmitted by the first motion transmission mechanism 104. In addition, the LIVC valve actuation motion 408 and the IEGR valve actuation motion 406 are transmitted to at least one engine valve via the second motion transmission mechanism 110, the selectable coupling mechanism 114, and the first motion transmission mechanism 104. In this case, the process of steps 502 and 506 is continuously repeated as long as engine operation in the second state is desired or until a switch to the first operating state is detected.

[0026] In a second embodiment, the valve actuation system illustrated in Figures 1 to 3 is configured to provide the engine valve 106 with both IEGR valve actuation and main intake valve actuation in addition to EIVC valve actuation. This is achieved by having a first valve actuation motion source 102 configured to provide EIVC valve actuation (referring to Figure 1, but also applicable to the systems in Figures 2 and 3), and a second valve actuation motion source 112 configured to provide main intake valve actuation and IEGR valve actuation.

[0027] Using the same light / heavy and solid / dashed curve representation as in Figure 4, Figure 6 illustrates a valve action including the main exhaust valve action 602. As described above, the EIVC valve action 604 is provided by a first valve action source, while a second valve action source provides the IEGR valve action 606 and the main intake action 608. In this example, the main intake valve action 608 is configured such that a handoff 610 occurs between the EIVC valve action 604 and the normal main intake valve action 608 at approximately two-thirds of the peak lift point during the opening phase of the EIVC valve action 604. Again, a specific handoff point 610 may be selected elsewhere as a design choice. As will be understood by those skilled in the art, the main intake valve action 608 in Figure 6 is configured to be substantially similar, if not identical, to the main intake valve action 404 shown in Figure 4, but nevertheless provides a slower intake valve closing compared to the EIVC valve action 604 shown in Figure 6.

[0028] A method for operating the engine valves, based on the valve operation example illustrated in Figure 6, will be described with reference to Figure 7. In this case as well, the method illustrated in Figure 7 may actually be carried out using a controller 116, for example, as illustrated in Figure 1. Starting in block 702, a determination is made as described above as to whether the request to operate the engine is in the first state or the second state.

[0029] If it is determined in block 702 that operation should continue according to the first state, the process proceeds to block 704, where, as described above, the selectable coupling mechanism 114 is maintained in its retracted / unlocked / motion-absorbing state or switched to that state. In the first state, according to this embodiment, at least one engine valve is operated according to the EIVC intake valve actuation 504, which is transmitted by the first motion transmission mechanism 104, while the valve actuation motion is not transmitted to at least one engine valve via the second motion transmission mechanism 110. The processes in steps 702 and 704 are repeated continuously as long as engine operation according to the first state is desired or until a switch to the second operating state is detected.

[0030] If it is determined in block 702 that a second operating state is desired, the process proceeds to block 706, where the selectable coupling mechanism 114 is maintained in its extended / locked / motion transmission state or switched to that state. In the second state, according to this embodiment, at least one engine valve is again actuated according to at least a portion of the EIVC intake valve actuation 604 (i.e., that portion of the EIVC intake valve actuation 604 that occurs before the handoff 610) as transmitted by the first motion transmission mechanism 104. In addition, the main valve actuation motion 608 and the IEGR valve actuation motion 606 are transmitted to at least one engine valve via the second motion transmission mechanism 110, the selectable coupling mechanism 114, and the first motion transmission mechanism 104. In this case, the process of steps 702 and 706 is continuously repeated as long as engine operation in the second state is desired or until a switch to the first operating state is detected.

[0031] While various embodiments of this disclosure have been described in conjunction with their specific implementations, it will be apparent to those skilled in the art that many alternative, modified, and variant forms are also evident. For example, the implementation examples in Figures 1, 2, and 3 illustrate a valve actuation system in which all valve actuation motion is transmitted to at least one engine valve 106 either solely through a first motion transmission mechanism 104 or in combination with a second motion transmission mechanism 110 and an optional coupling mechanism 114, but the technology described herein is not limited to such systems.

[0032] For example, U.S. Patent Application No. 18 / 540,611 ("'611 Application"), assigned to the same assignee as this application, describes a valve actuation system in which first and second rocker assemblies are provided, each having its own lost-motion component, to provide individual control of the valve actuation motion for each engine valve. More specifically, as illustrated and described in the '611 Application with reference to Figures 1 and 2 of that Application, each of the first and second rocker assemblies comprises an input rocker and an output rocker, with each lost-motion component arranged in series between the input and output rockers. In addition, a one-way coupling mechanism is provided between the output rockers, thereby transmitting valve actuation provided to the second output rocker by a primary valve actuation motion source to the first output rocker, while valve actuation motion provided to the first output rocker by an auxiliary valve actuation motion source is not transmitted to the second output rocker.

[0033] If we consider the first output rocker, input rocker, and first lost-motion component of the first rocker assembly in Application 611 to be the first motion transmission mechanism 102, the second motion transmission mechanism 110, and the selectable coupling mechanism 114 of this Application, respectively, then the same combination of main valve, LIVC valve, and IEGR valve operation as described can be achieved. That is, when the first lost-motion component of Application 611 is operated in its motion absorption state, the first output rocker of Application 611 is provided with main valve acting motion (via the second output rocker and unidirectional coupling), but no auxiliary valve acting motion (i.e., LIVC and IEGR valve acting motion). On the other hand, when the first lost-motion component of Application 611 is operated in its motion transmission state, the first output rocker of Application 611 is provided with main valve acting motion (again, via the second output rocker and unidirectional coupling), and any auxiliary valve acting motion is provided via the first input rocker of Application 611.

[0034] Therefore, preferred embodiments of the present invention described herein are for illustrative purposes only and are not limiting insofar as any modifications thereof fall within the scope of the appended claims and their equivalents.

Claims

1. A valve actuation system for acting on at least one intake engine valve in an internal combustion engine, wherein the valve actuation system is A first valve actuation motion source and a first motion transmission mechanism operably connected to at least one intake engine valve, wherein the first valve actuation motion source is configured to provide at least main valve actuation motion, A second motion transmission mechanism operably connected to a second valve actuation motion source, wherein the second valve actuation motion source is configured to provide intake valve closing (LIVC) valve actuation motion and internal exhaust gas recirculation (IEGR) valve actuation motion that are at least slower than the main valve actuation motion; The system comprises a selectable coupling mechanism disposed between the first motion transmission mechanism and the second motion transmission mechanism, When the selectable coupling mechanism is operated in the first state, the main valve operating motion is transmitted to the at least one intake engine valve via the first motion transmission mechanism. A valve actuation system in which, when the selectable coupling mechanism is operated in a second state, at least a portion of the main valve actuation motion is transmitted to the at least one intake engine valve via the first motion transmission mechanism, and the LIVC valve actuation motion and the IEGR valve actuation motion are transmitted to the at least one intake engine valve via the second motion transmission mechanism, the coupling mechanism, and the first motion transmission mechanism.

2. The valve operating system according to claim 1, wherein the selectable coupling mechanism comprises a selectable hydraulic actuator, the hydraulic actuator being retracted during a first state and extended during a second state.

3. The valve operating system according to claim 1, wherein the selectable coupling mechanism comprises a selectable mechanical locking mechanism, the mechanical locking mechanism being unlocked during the first state and locked during the second state.

4. The valve operating system according to claim 1, wherein when the selectable coupling mechanism is operated in the second state, a handoff occurs from the main valve operating motion to the LIVC valve operating motion.

5. The valve operating system according to claim 1, wherein the IEGR valve operating motion does not cause a handoff with the main valve operating motion.

6. An internal combustion engine comprising the valve operating system described in claim 1.

7. A method for operating the at least one intake engine valve in an internal combustion engine, comprising: a first valve actuation motion source; a first motion transmission mechanism operably connected to at least one intake engine valve; a second motion transmission mechanism operably connected to a second valve actuation motion source; and a selectable coupling mechanism disposed between the first motion transmission mechanism and the second motion transmission mechanism, The selectable coupling mechanism is operated in a first state in which at least the main valve actuation motion provided by the first valve actuation motion source is transmitted to the at least one intake engine valve via the first motion transmission mechanism. The selectable coupling mechanism is operated in a second state in which, in addition to at least a portion of the main valve acting motion transmitted via the first motion transmission mechanism, a second valve acting motion provided by the second valve acting motion source is transmitted to the at least one intake engine valve via the second motion transmission mechanism, the coupling mechanism, and the first motion transmission mechanism. A method wherein the second valve actuation motion is configured to provide an intake valve closing (LIVC) valve actuation motion that is at least slower than the main valve actuation motion, and to provide an internal exhaust gas recirculation (IEGR) valve actuation motion.

8. A valve actuation system for acting on at least one intake engine valve, wherein the valve actuation system is A first valve actuation motion source that provides at least intake valve delayed closing (EIVC) valve actuation motion, and a first motion transmission mechanism operably connected to the at least one intake engine valve, A second valve actuation motion source, configured to provide at least main valve actuation motion and internal exhaust gas recirculation (IEGR) valve actuation motion, is operably connected to the second valve actuation motion source, The system comprises a selectable coupling mechanism disposed between the first motion transmission mechanism and the second motion transmission mechanism, When the selectable coupling mechanism is operated in the first state, the EIVC valve actuation motion provided by the first valve actuation motion source is transmitted to the at least one intake engine valve via the first motion transmission mechanism. A valve actuation system in which, when the selectable coupling mechanism is operated in a second state, at least a portion of the EIVC valve actuation motion is transmitted to the at least one intake engine valve via the first motion transmission mechanism, and the main valve actuation motion and the IEGR valve actuation motion are transmitted to the at least one intake engine valve via the second motion transmission mechanism, the coupling mechanism, and the first motion transmission mechanism.

9. The valve operating system according to claim 8, wherein the selectable coupling mechanism comprises a selectable hydraulic actuator, the hydraulic actuator being retracted during a first state and extended during a second state.

10. The valve operating system according to claim 8, wherein the selectable coupling mechanism comprises a selectable mechanical locking mechanism, the mechanical locking mechanism being unlocked during the first state and locked during the second state.

11. The valve operating system according to claim 1, wherein when the selectable coupling mechanism is operated in the second state, a handoff occurs from the EIVC valve operating motion to the main intake valve operating motion.

12. The valve operating system according to claim 8, wherein the IEGR valve operating motion does not cause a handoff with the EIVC valve operating motion.

13. An internal combustion engine comprising the valve operating system described in claim 8.

14. A method for operating the at least one intake engine valve in an internal combustion engine, comprising: a first valve actuation motion source; a first motion transmission mechanism operably connected to at least one intake engine valve; a second motion transmission mechanism operably connected to a second valve actuation motion source; and a selectable coupling mechanism disposed between the first motion transmission mechanism and the second motion transmission mechanism, The selectable coupling mechanism is operated in a first state in which at least EIVC valve operating motion provided by the first valve operating motion source is transmitted to the at least one intake engine valve via the first motion transmission mechanism. The selectable coupling mechanism is operated in a second state in which, in addition to the EIVC valve acting motion transmitted via the first motion transmission mechanism, a second valve acting motion provided by the second valve acting motion source is transmitted to the at least one intake engine valve via the second motion transmission mechanism, the coupling mechanism, and the first motion transmission mechanism. A method wherein the second valve acting motion provided by the second valve acting motion source includes at least a main valve acting motion and an internal exhaust gas recirculation (IEGR) valve acting motion.

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