Valve actuation system including hydraulic lash adjuster operated via one-way coupling mechanism

Abstract

A valve actuation system includes a first rocker arm assembly operatively connected to a first valve actuation motion source and connected to a first engine valve with a first lost motion component disposed in series between a first input rocker arm and a first output rocker arm. A second rocker arm assembly is operatively connected to a second valve actuation motion source and to a second engine valve, wherein a second lost motion component is disposed in series between the second input rocker arm and the second output rocker arm. The one-way coupling mechanism is arranged such that the second valve actuation motion is transmitted to the first output rocker arm but the first valve actuation motion is not transmitted to the second output rocker arm. Further, a primary hydraulic lash adjuster is configured in the second rocker arm assembly such that the primary hydraulic lash adjuster operates the first output rocker arm via a one-way coupling mechanism.

Description

Technical Field

[0001] This disclosure generally relates to a system for actuating engine valves in an internal combustion engine, and more particularly to a valve actuation system including a hydraulic clearance adjuster operated via a one-way coupling mechanism. Background Technology

[0002] Co-pending U.S. Patent Application No. 18 / 540,611 (“611 Application”), filed December 14, 2023 (the teachings of which are incorporated herein by reference), discloses as follows Figure 1 An embodiment of a valve actuation system is schematically depicted. Specifically, the valve actuation system 100 includes a first rocker arm assembly 110 and a second rocker arm assembly 140. As shown, the first rocker arm assembly 110 is operatively connected to a first valve actuation motion source 120, and the second rocker arm assembly 140 is operatively connected to a second valve actuation motion source 150. A first engine valve 162 and a second engine valve 164 (both of which may be, for example, intake or exhaust valves) are associated with cylinders 160 of an internal combustion engine, and these valves 162, 164 are operatively connected to corresponding rocker arm assemblies in the first rocker arm assembly 110 and the second rocker arm assembly 140. Thus, the first rocker arm assembly 110 and the second rocker arm assembly 140 operate to actuate (i.e., open and close) the engine valves 162, 164 according to the instructions of the first valve actuation motion source 120 and the second valve actuation motion source 150 (and subject to the operation of any incorporated aerodynamic components), as described in more detail below. Although Figure 1 Only a single cylinder 160 is illustrated, but it should be understood that an internal combustion engine may include more than one cylinder, and the valve actuation system described herein can be applied to any number of cylinders in a given internal combustion engine.

[0003] Valve actuation sources 120, 150 may include any combination of elements (such as cams) capable of providing valve actuation motion. Each of the valve actuation sources 120, 150 may be dedicated to providing primary exhaust motion, primary intake motion, auxiliary motion, or a combination of primary exhaust motion or primary intake motion and auxiliary motion. For example, in one embodiment, the first motion source 120 is configured to provide auxiliary valve actuation motion, and the second motion source 150 is configured to provide primary valve actuation motion (either exhaust or intake).

[0004] In this embodiment, the first rocker arm assembly 110 includes a first input rocker arm 112, a first aerodynamic component 114, and a first output rocker arm 116 arranged in series. Specifically, the first input rocker arm 112 is operatively connected to a first valve actuation motion source 120 and the first output rocker arm 116 is operatively connected to a first engine valve 162, wherein the first aerodynamic component 114 is operatively connected to and disposed between the first input rocker arm 112 and the first output rocker arm 116. The first input rocker arm 112 and the first output rocker arm 116 may include center-pivoted (possibly shaft-mounted) rocker arms, but it should be understood that the teachings of this disclosure are also equivalently applicable to end-pivoted rocker arms. Optionally, as disclosed in '611 application, a first hydraulic clearance adjuster (HLA) 118 may be included in the first rocker arm assembly 110. In the illustrated example, as taught in '611 application, a first HLA 118 is deployed in a first output rocker arm 116, which may include a hydraulic passage (not shown) adapted to supply hydraulic fluid to the first HLA 118. '611 application further teaches that the first HLA 118 may alternatively be deployed as part of other components 112, 114 constituting the first rocker arm assembly 110. Additionally, '611 application teaches that when the first HLA 118 is provided, it may be desirable to control the operation of the first HLA (e.g., to make the first HLA stroke-limited) to ensure that placing the first pneumatic member 114 in its unlocked / motion-absorbing state does not allow the HLA 118 to absorb all clearance in the first rocker arm assembly 110, which could result in over-extension of the first engine valve 162 when the first pneumatic member 114 is operated again in its locked / motion-transmitting state. Alternatively, '944 application teaches that, in this case, engine valve overextension can be prevented by the operation of HLA 118, by combining a stroke limit in the first aerodynamic component 114 with a bias force supplied by the first aerodynamic component 114 sufficient to prevent overextension of HLA 118.

[0005] like Figure 1Further description suggests that an engine controller 180 may be provided and operatively connected thereto to the first aerodynamic component 114. The engine controller 180 may include any electronic, mechanical, hydraulic, electro-hydraulic, or other type of control device for controlling the operation of the aerodynamic mechanism 114, i.e., switching between its corresponding locked and unlocked states as described above. For example, the engine controller 180 may be implemented by a microprocessor and a corresponding memory storing executable instructions for implementing the desired control functions, including those known in the art and described below. It should be understood that other functionally equivalent implementations of the engine controller 180 (e.g., appropriately programmed application-specific integrated circuits (ASICs), etc.) may be employed. Furthermore, the engine controller 180 may include a peripheral device located between the engine controller 180 and the first aerodynamic component 114, which allows the engine controller 180 to control the operating state of the aerodynamic device 114. For example, if the pneumatic device 114 is a hydraulically controlled mechanism (i.e., responding to the absence of hydraulic fluid at the input or the application of hydraulic fluid to the input), such peripheral devices may include suitable solenoids.

[0006] like Figure 1 As shown, the control of the first aerodynamic component 114 by the engine controller 180 is provided directly to the first aerodynamic component 114. However, in practice, such control may be achieved via a path through at least one of the adjacent input rocker arms 112 or output rocker arms 116. For example, in the various embodiments described herein, such control is achieved under the control of the engine controller 180 by using hydraulic fluid supplied via one or more fluid passages formed in the first input rocker arm 112 or the first output rocker arm 116. However, as those skilled in the art will understand, equivalent control schemes may be employed to achieve this objective.

[0007] like Figure 1As further shown, the second rocker arm assembly 140 includes a second input rocker arm 142, a second actuating component 144, and a second output rocker arm 146 arranged in series. Specifically, the second input rocker arm 142 is operatively connected to a second valve actuation motion source 150, and the second output rocker arm 146 is operatively connected to a second engine valve 162, wherein the actuating component 144 is operatively connected to and disposed between the second input rocker arm 142 and the second output rocker arm 146. The second input rocker arm 142 and the second output rocker arm 146 may again include a centrally pivoted (possibly shaft-mounted) rocker arm, but again it should be understood that the teachings of this disclosure are equivalently applicable to end-pivot rocker arms. Optionally, as disclosed in '611 application, a second hydraulic clearance adjuster (HLA) 148 may be included in the second rocker arm assembly 140. In the illustrated example, as taught in '611 application, a second HLA 148 is deployed in a second output rocker arm 146, which may include a hydraulic passage (not shown) adapted to supply hydraulic fluid to the second HLA 148. '611 application further teaches that the second HLA 148 may alternatively be deployed as part of other components 142, 144 constituting the second rocker arm assembly 110. Additionally, '611 application teaches that, as with HLA 118, in the presence of a second aerodynamic component 144 in the second rocker arm assembly 140, it may be desirable to control the operation of the second HLA 148 to prevent overextension of the second engine valve 164. Alternatively, '611 application teaches that, again, in this case, engine valve overextension may be prevented alternatively by the operation of the HLA 148, by combining a stroke limit in the second aerodynamic component 144 with a biasing force supplied by the first aerodynamic component 114 sufficient to prevent overextension of the HLA 148.

[0008] The controller 180 is configured to be operatively coupled to the second pneumatic component 144, thereby controlling the operation of the second pneumatic component 144. Again, although the controller 180 is illustrated as directly controlling the second pneumatic component 144, it should be understood that such control can be facilitated by paths provided in adjacent components (e.g., the second input rocker arm 142 and / or the second output rocker arm 146).

[0009] The illustrated embodiment is characterized by a one-way coupling (OWC) 170 provided between the second output rocker arm 146 of the second rocker arm assembly 140 and the first output rocker arm 116 of the first rocker arm assembly 110. The second output rocker arm 146 can drive the first output rocker arm 116, but not vice versa, as shown below. Figure 1The unidirectional arrow shown indicates the connection between the second rocker arm 146, the one-way connector 170, and the first output rocker arm 116. That is, the one-way connector 170 exists such that valve actuation provided by the second valve actuation motion source 150 can be applied to the first output rocker arm 116, while valve actuation provided by the first valve actuation motion source 120 cannot be applied to the second output rocker arm 146. In one embodiment, the one-way connector 170 is implemented using a fixed element, such that the one-way connector 170 is "always there," meaning it is not selectable.

[0010] Application submitted on '611' Figure 1 In alternative embodiments, as taught but not illustrated herein, the first rocker arm assembly 110 is as described above, but the second rocker arm assembly 140 may include a single second rocker arm configured to receive valve actuation motion directly from the second motion source 150. That is, in this embodiment, the second rocker arm assembly 140 includes only the second output rocker arm 146, and does not include the second input rocker arm 142 or the second actuation component 144.

[0011] In any case, such as Figure 1 As shown, the valve actuation system 100 provides various options for actuating engine valves 162 and 164. For example, when the second valve actuation motion source 150 provides the primary valve actuation motion and the first valve actuation motion source 120 provides the auxiliary valve actuation motion, the first actuation component 114 can be controlled to be in its unlocked or motion-absorbing state, such that the auxiliary valve actuation motion applied to the first input rocker arm 112 is not transmitted by the first actuation component 114 to the first output rocker arm 116 or therefore not transmitted to the first engine valve 162. Additionally, the second actuation component 144 can also be controlled to be in its unlocked or motion-absorbing state, such that the primary valve actuation motion applied to the second input rocker arm 142 is not transmitted by the second actuation component 144 to the second output rocker arm 146, or therefore not transmitted to the second engine valve 164 (or, by means of the one-way connector 170, not transmitted to the first engine valve). This control over engine valves 162 and 164 can be used to achieve, for example, cylinder 160 or cylinder deactivation (CDA) of the engine.

[0012] Alternatively, based on the same example where the first aerodynamic component 114 operates again in its unlocked / motion-absorbing state and the second aerodynamic component 144 operates in its locked / motion-transmitting state, auxiliary valve actuation motion is not transmitted to the first engine valve 162, while primary valve actuation motion is transmitted to both the first valve 162 and the second valve 164. This control of the engine valves 162 and 164 can be used, for example, to achieve forward power generation operation of the engine.

[0013] In another alternative embodiment, based on the same example where the first aerodynamic component 114 operates in its locked / motion-transmitting state and the second aerodynamic component 144 operates in its locked / motion-transmitting state, auxiliary valve actuation motion is transmitted to the first engine valve 162 and primary valve actuation motion is transmitted to both the first valve 162 and the second valve 164. This control of the engine valves 162, 164 can be used to achieve, for example, conventional four-stroke compression-release engine braking operation, or to provide other additional auxiliary valve actuation motions (e.g., internal exhaust gas recirculation (IEGR), variable valve actuation (VVA), exhaust valve advance opening (EEVO), intake valve delay closing (LIVC), swirl control, etc.).

[0014] In yet another alternative embodiment, based on the same example where the first aerodynamic component 114 operates in its locked / motion-transmitting state and the second aerodynamic component 144 operates in its unlocked / motion-absorbing state, auxiliary valve actuation motion is transmitted to the first engine valve 162, while primary valve actuation motion is not transmitted to either the first valve 162 or the second valve 164. This control of the engine valves 162, 164 can be used to achieve operating modes where auxiliary valve actuation is desired but primary valve actuation is not. For example, such operating modes may include so-called 2-stroke or 1.5-stroke compression-release engine braking operations.

[0015] Application 611 further teaches specific embodiments of the first aerodynamic component 114 and the second aerodynamic component 144. Figure 2 An example of this embodiment of the pneumatic component 200 taught in application '611' is illustrated. A cross-section of the pneumatic component 200 is shown, thereby better illustrating the hydraulically controlled locking mechanism 210, which constitutes a sub-assembly of the pneumatic component 200 and is deployed between the housing 220 and the plunger 222. Although the housing 220 may be formed as a single element, Figure 2 In the illustrated example, the closed end of housing 220 is provided by an end cap 221 attached to housing 220. A plunger spring 224 is disposed on the exterior of housing 220 and plunger 222. In the illustrated embodiment, plunger spring 224 is disposed between a flange 226 formed on or attached to the outer surface of plunger 222 and a shoulder 228 formed in housing 220. Thus, plunger spring 224 biases housing 220 and plunger 222 away from each other. It should be understood that plunger spring 224 may be disposed elsewhere between housing 220 and plunger 222, for example, within housing 220.

[0016] like Figure 2As shown, the locking mechanism 210 includes a plunger 222 slidably disposed within a housing bore 230 formed in and extending from the first end of the housing 220 along the longitudinal axis of the aerodynamic component 200, and preferably concentric with the first end of the housing. An inner plunger 232 is slidably disposed in a longitudinal bore 234 formed in the plunger 222. An inner plunger spring 242 is disposed between the inner plunger 242 and a plunger cap 245, thereby tending to bias the inner plunger out of the bore 234. A locking element in the form of a wedge 236 is provided, configured to engage an annular recess 238 formed in the surface defining the housing bore 230.

[0017] The illustrated implementation is the normally unlocked locking mechanism 210, i.e., without hydraulic control applied to the inner plunger 232 via the (in this case) pneumatic hydraulic passage 240, the inner piston spring 242 biases the inner plunger 232 into the appropriate position, causing the wedge 236 to retract radially through the opening formed in the plunger 220. Therefore, the wedge 236 disengages from the outer recess 238, thereby effectively unlocking the plunger 222 relative to the housing 220, i.e., allowing the plunger 222 to slide freely within the housing 220, under the bias provided by the plunger spring 224. In this unlocked state, any valve actuation applied to the pneumatic component 200 will cause the plunger 222 to reciprocate within its bore 230. Thus, and assuming that the stroke of plunger 222 within its bore 230 exceeds the maximum range of any applied valve actuation movement (i.e., plunger 222 cannot descend to its lowest point within its bore 230), such valve actuation movement is not transmitted by the actuation component 200 and is effectively discarded. Alternatively, the stroke of plunger 222 within its bore 230 may be configured such that plunger 222 "descends to its lowest point," i.e., contacts the closed end of bore 230, so as to always provide "fail-safe" valve lift in the event of a failure of locking mechanism 210.

[0018] On the other hand, the input receiving end of the inner plunger 232 via the pneumatic hydraulic channel 240 (such as...) Figure 3 The bottom surface (shown as A) provides hydraulic fluid that is sufficiently pressurized to overcome the bias of the inner piston spring 242, causing the inner plunger 232 to translate upward within the bore 234 (as depicted), forcing the wedge 236 to extend radially through the opening formed in the plunger 222 and engage with the outer recess 238, thereby effectively locking the plunger 222 relative to the housing 220. In this locked state, valve actuation movements (whether primary or auxiliary) applied to the aerodynamic component 200 will cause the plunger 222 to engage the housing 220, thereby transmitting such valve actuation movements.

[0019] It should be noted that when the locking mechanism 210 is in the locked state, the longitudinal extent of the outer recess 238 is greater than the thickness of the wedge-shaped portion 236, allowing for a small amount of movement between the plunger 222 and the housing 220. This additional space provided by the outer recess 238 facilitates locking / unlocking the locking mechanism 210 when the pneumatic component 200 is unloaded.

[0020] The bias applied by the plunger spring 224 can be selected to further ensure that adjacent valve mechanism components 252, 254 (e.g., rocker arms as described below, or such additional upstream or downstream valve mechanism components in the system, not shown) are biased to continuous contact with the corresponding endpoints of the valve mechanism (i.e., the valve actuation motion source and the engine valve).

[0021] although Figure 2 Specific embodiments and constructions of the pneumatic component 200 are illustrated, but it should be understood that other equivalent constructions may be used, and this disclosure is not limited in this respect. For example, as previously described, the illustrated pneumatic component 200 is a normally unlocked pneumatic component. However, as those skilled in the art will understand, a pneumatic component of a generally unlocked type may be used.

[0022] Refer again Figure 1 If the first aerodynamic component 114 (such as Figure 2 With the illustrated aerodynamic component 200 in the unlocked state, and valve actuation motion (e.g., a major valve event) from the second valve actuation motion source 150 transmitted to the first output rocker arm 116 by the one-way coupling 170, the operation of the plunger spring 224 will cause the housing 220 and the plunger 222 to slide away from each other. That is, when the first output rocker arm 116 is pushed toward the first engine valve 162 as commanded by the one-way coupling 170, the plunger spring 224 will bias the plunger 222 and the first input rocker arm 112 toward the first motion source 120, and bias the housing 220 toward the first output rocker arm 116. (Reference) Figure 2 Separation of housing 220 and plunger 222 will result in an increase in the so-called "ball-to-ball" distance D (referring to the hemispherical ball joints 244, 243, which are used to hold the pneumatic component 200 in the proper position between adjacent valve mechanism components 252, 254, while still allowing the pneumatic component 200 to rotate relative to the adjacent valve mechanism components 252, 254). However, if the ball-to-ball distance D is not limited below its maximum value, there is a possibility that the wedge 238 may extend beyond the hole 230 of housing 220 and thereby detach, or even that the plunger 222 may detach from housing 220.

[0023] To prevent this from happening, a "carrying" feature has been proposed (e.g., in U.S. Patent Application No. 18 / 484,053, filed October 10, 2023) to be implemented between the first output rocker arm 116 and the first input rocker arm 112, such as... Figure 1 Reference numeral 190 is schematically illustrated in the accompanying drawings. The carrying feature 190 is designed such that rotation of the first output rocker arm 116 caused by the one-way coupling mechanism 170 will cause the carrying feature 190 to engage the first input rocker arm 112, and cause the input rocker arm 112 to also rotate as commanded by the first output rocker arm 116 (which is again commanded by the one-way coupling mechanism 170). The carrying features 190 (such as the corresponding contact surfaces on the first input rocker arm 112 and the first output rocker arm 116 aligned with each other) are also designed such that rotation of the input rocker arm 112 will be caused before the ball-to-ball distance D of the idler components 114, 200 exceeds its maximum value, thereby preventing the aforementioned problems.

[0024] While carrying feature 190 can successfully ensure that the ball-to-ball distance D of the first aerodynamic components 114 and 200 does not exceed the desired maximum value, it may cause other difficulties under certain conditions. For example, Figure 1 The valve actuation system can be used to actuate the exhaust valve during so-called high power density (HPD) compression-release engine braking. Specifically, and as... Figure 3 As shown, the first valve actuation source 120 can provide an auxiliary exhaust valve actuation movement 302 (illustrated in thin lines) for achieving braking of a 1.5-stroke or 2.0-stroke HPD engine (including a first compression release event 306, a first brake gas recirculation (BGR) event 308, a second compression release exhaust port 310, and a second BGR event 312), while the second valve actuation source 150 can provide an exhaust main event 304. As is known in the art, during braking of a 1.5-stroke HPD engine, an intake main event 305 is provided, while the exhaust main event 304 is simultaneously discarded and replaced by the auxiliary exhaust valve actuation movement 302, while during braking of a 2.0-stroke HPD engine, both the exhaust main event 304 and the intake main event 305 are discarded and replaced by the auxiliary exhaust valve actuation movement 302 and the auxiliary intake valve actuation movement, respectively. Figure 3 (Not shown in the text) is replaced.

[0025] In this configuration, and assuming that the carrying feature 190 is implemented, when the first aerodynamic component 114 is in its unlocked state but the second aerodynamic component 144 is in its locked state, the rotation of the first output rocker arm 116 via the one-way coupling mechanism 170 will similarly cause the carrying feature 190 to rotate the first input rocker arm 112 according to the main exhaust event 304 provided by the second motion source 150. Therefore, the first input rocker arm 112 will be approximately at point 314 (i.e., at such point 314). Figure 3At approximately 180° crank angle (as shown), contact with the first motion source 120 is lost, at which point the lift provided to the first output rocker arm 116 by the main exhaust event 304 exceeds the lift provided by the first BGR event 308 provided to the first input rocker arm 112. However, during the closing of the main exhaust event 304, during the period T in which the main exhaust event 304 and the second compression release event 310 overlap, the first input rocker arm 112 will move toward the first motion source 120 (i.e., the cam) at a relatively high speed, while the cam lob providing the second compression release event 310 will move toward the first input rocker arm 112. Therefore, the first input rocker arm 112 (more specifically, the cam follower deployed thereon) will be approximately at point 316 (i.e., at a point where...) Figure 3 At approximately a 350° crank angle (as shown), the first input rocker arm 112 experiences a significant collision with the first motion source 120, at which point the lift provided by the first BGR event 308 to the first input rocker arm 116 exceeds the lift provided by the main exhaust event 304. Such a high-speed collision can potentially damage the valve mechanism.

[0026] Valve actuation systems that overcome the limitations described above while still providing a variety of valve actuation functions and flexibility, particularly for aerodynamic components in HPD engine braking operations, would be a welcome and representative advancement in the field. Summary of the Invention

[0027] This disclosure describes various embodiments of a valve actuation system for actuating at least two engine valves in an internal combustion engine. In one embodiment, such a system includes a first rocker arm assembly operatively connected to a first valve actuation motion source and connected to a first engine valve of at least two engine valves. The first rocker arm assembly includes a first actuation member arranged in series with a first input rocker arm and a first output rocker arm, the first input rocker arm being configured to receive a first valve actuation motion from the first valve actuation motion source, and the first output rocker arm being configured to deliver the first valve actuation motion to the first engine valve. The first actuation member is operable in a motion absorption state to prevent the first valve actuation motion from being transmitted from the first input rocker arm to the first output rocker arm, and is operable in a motion transmission state to transmit the first valve actuation motion from the first input rocker arm to the first output rocker arm. A second rocker arm assembly is operatively connected to a second valve actuation motion source and connected to a second engine valve of at least two engine valves. The second rocker arm assembly includes a second actuating component arranged in series with a second input rocker arm and a second output rocker arm. The second input rocker arm is configured to receive a second valve actuation motion from a second valve actuation motion source, and the second output rocker arm is configured to deliver the second valve actuation motion to a second engine valve. The second actuating component is operable in a motion absorption state to prevent the second valve actuation motion from being transmitted from the second input rocker arm to the second output rocker arm, and is operable in a motion transmission state to transmit the second valve actuation motion from the second input rocker arm to the second output rocker arm. A one-way coupling mechanism is disposed between the first output rocker arm and at least one second rocker arm, such that the second valve actuation motion is transmitted from at least one second rocker arm to the first output rocker arm, and the first valve actuation motion is not transmitted from the first output rocker arm to at least one second rocker arm. Furthermore, a main hydraulic clearance adjuster is disposed in the second rocker arm assembly, such that the main hydraulic clearance adjuster operates the first output rocker arm via the one-way coupling mechanism. In one embodiment, the main hydraulic clearance adjuster may be disposed in the second output rocker arm.

[0028] In another embodiment, each of the first input rocker arm, the first output rocker arm, the second input rocker arm, and the second output rocker arm includes a shaft-mounted half rocker arm.

[0029] In another embodiment, the unidirectional coupling mechanism includes a second extension forming part of at least one second output rocker arm and a first extension forming part of a first output rocker arm, wherein the first extension and the second extension are configured to contact each other.

[0030] In another embodiment, the first aerodynamic component includes a hydraulically controlled locking mechanism. Furthermore, the first aerodynamic component may include a first spring that biases the first input rocker arm toward the first valve actuation motion source and the first output rocker arm toward the first engine valve. Further, the first aerodynamic component may have a longitudinal range sufficient to accommodate movement applied to the first output rocker arm via a one-way coupling mechanism. The first aerodynamic component may also be configured to have a stroke-limited capability.

[0031] In another embodiment, the system may include an auxiliary hydraulic clearance adjuster disposed between the second output rocker arm and the second engine valve. In this case, the auxiliary clearance adjustment force provided by the auxiliary hydraulic clearance adjuster is preferably less than the primary clearance adjustment force provided by the primary hydraulic clearance adjuster.

[0032] In one embodiment, the second aerodynamic component includes a hydraulically controlled locking mechanism. Furthermore, the second aerodynamic component may include a second spring that biases the first input rocker arm toward the second valve actuation motion source and the second output rocker arm toward the second engine valve. Further, the second aerodynamic component may be configured to have a stroke-limited capability.

[0033] In another embodiment, a system includes a first rocker arm assembly operatively connected to a first valve actuation motion source and connected to a first engine valve of at least two engine valves. The first rocker arm assembly includes a first actuation member arranged in series with a first input rocker arm and a first output rocker arm, the first input rocker arm being configured to receive a first valve actuation motion from the first valve actuation motion source, and the first output rocker arm being configured to deliver the first valve actuation motion to the first engine valve. The first actuation member is operable in a motion absorption state to prevent the first valve actuation motion from being transmitted from the first input rocker arm to the first output rocker arm, and is operable in a motion transmission state to transmit the first valve actuation motion from the first input rocker arm to the first output rocker arm. A second rocker arm assembly is operatively connected to a second valve actuation motion source and connected to a second engine valve of at least two engine valves. The second rocker arm assembly includes at least one second rocker arm configured to receive a second valve actuation motion from the second valve actuation motion source and configured to deliver the second valve actuation motion to a second engine valve. A one-way coupling mechanism is disposed between the first output rocker arm and at least one second rocker arm, such that the second valve actuation motion is transmitted from at least one second rocker arm to the first output rocker arm, and the first valve actuation motion is not transmitted from the first output rocker arm to at least one second rocker arm. In this embodiment, the first rocker arm assembly includes a hydraulic clearance adjuster, and the first valve actuation motion source includes a refill cycle, which includes a sub-base circle lift configured to eliminate the load placed on the hydraulic clearance adjuster by the expansion of the first aerodynamic component. Attached Figure Description

[0034] The foregoing and other features and advantages will be discussed in detail in the following non-limiting description of a particular embodiment, in conjunction with the accompanying drawings, wherein: Figure 1 This is a schematic diagram of an embodiment of a valve actuation system including aerodynamic components that can benefit from the teachings of this disclosure; Figure 2 It can be used to implement Figure 1 A cross-sectional view of an example of the aerodynamic components of the system; Figure 3 It is a graph illustrating the main valve events and auxiliary valve events used in conjunction with HPD engine braking; Figure 4 It can be used to implement Figure 1 A cross-sectional view of an alternative example of a system that does not require aerodynamic components with distinctive features; Figure 5 This is a schematic diagram of an embodiment of a valve actuation system including aerodynamic components, based on the teachings of this disclosure; Figures 6 to 8 Examples are given based on Figure 5 Valve actuation system; Figure 9 This is a schematic diagram of an alternative embodiment of a valve actuation system including aerodynamic components, based on the teachings of this disclosure; and Figure 10 This is a graph illustrating the refill cycle of a hydraulic gap adjuster provided by a first motion source according to the currently preferred embodiment. Detailed Implementation

[0035] As used herein, the term “operationally connected” is understood to mean at least a functional relationship between two components, that is, the components to be protected must be connected in a manner that performs the indicated function (potentially including the presence of an intermediary element or component).

[0036] Application 611 further describes an alternative to the hollow component used in carrying feature 190, thereby avoiding the collision problem of carrying feature 190 with the first input rocker arm 112. Figure 4 An example of this aerodynamic component 200' is shown. In Figure 2 and Figure 4 In the accompanying drawings, elements with similar reference numerals are essentially similar in structure and function, while Figure 4 The reference numerals including the apostrophe (') indicate that they are characterized by having different features from those in the figure. Figure 2 The structural and / or functional elements of the exemplified corresponding elements are described below. Figure 4In the illustrated embodiment, the aerodynamic component 200' again includes a housing 220 having a longitudinal bore 230 formed therein and a plunger 222 slidably disposed in the bore 230. Similarly, an inner plunger 232 is disposed in a bore 234 formed in the plunger 222 and an inner plunger spring 242 disposed between the inner plunger 232 and the plunger cap 245 biased out of the bore 234.

[0037] Furthermore, the inner plunger 232 is configured to provide a normally unlocked operation, i.e., without the application of hydraulic control to the inner plunger 232, the inner plunger spring 242 biases the inner plunger 232 into the appropriate position such that the wedge 236 does not extend radially out of the opening formed in the plunger 232 and therefore does not engage the outer annular recess 238', thereby effectively unlocking the plunger 222 relative to the housing 220 and allowing the plunger 222 to slide freely within its bore 230 under the bias provided by the plunger spring 224.

[0038] On the other hand, the input receiving end of the inner plunger 232 (such as...) Figure 4 The bottommost surface shown provides hydraulic fluid that is sufficiently pressurized to overcome the bias of the inner piston spring 242, causing the inner plunger 232 to translate within the bore 234, thus forcing the wedge portion 236 to extend and engage with the outer recess 238' (as shown). Figure 4 As shown), this effectively locks the plunger 222 relative to the housing 220.

[0039] Another feature of housing 220 is that the annular outer recess 238' has a larger diameter than... Figure 2 The annular recess 238' depicted has a larger longitudinal range. Therefore, when the plunger 222 unlocks from the housing 220 and the first output rocker arm 116 is commanded by the one-way coupling mechanism 170 as described above, the larger range of the annular recess 238' allows for a larger maximum ball-to-ball distance D' without the risk of the wedge 236 or the plunger 222 dislodging. Furthermore, given this larger maximum ball-to-ball distance D', the housing 220 and the plunger 222 can be biased further by the plunger spring 224, causing the first input rocker arm 112 to be biased into continuous contact with the first motion source 120. Therefore, since the first input rocker arm 112 can remain in contact with the first motion source 120, the aforementioned collision between the first input rocker arm 112 and the first motion source 120 is avoided.

[0040] Figure 4An additional feature of the illustrated pneumatic component 200' is the provision of a stroke limiting feature to prevent the plunger 222 from excessively extending out of the housing 220. In the illustrated example, this stroke limiting feature includes a shoulder 402 formed in the wall defining the housing bore 230 and a corresponding flange or lip 404 formed at the end of the plunger 222 that overlaps with the shoulder 402. In one embodiment, the flange 404 is configured to engage the shoulder 402 when the plunger 222 moves out of (away from) the housing 220, thereby preventing the plunger 222 from extending out of the housing 220 beyond a maximum distance in all cases.

[0041] As mentioned above, in contrast to Figure 1 As described, HLA 118, 148 may optionally be included in the first rocker arm assembly 110 and the second rocker arm assembly 140. However, as described above, Figure 4 The illustrated aerodynamic component 200' allows the plunger spring 224 to constantly bias both the housing 220 and the plunger 222, and thus also bias the first input rocker arm 112 and the first output rocker arm 116. If HLA 118 as... Figure 1 As illustrated, the constant bias applied to the first output rocker arm 116 by the plunger spring 224 between the first output rocker arm 116 and the first valve 162 will cause the HLA 118 to collapse and / or prevent the HLA from expanding as required for normal operation.

[0042] To accommodate the presence of an HLA (such as HLA 118) in the first rocker arm assembly 110, the first valve actuation motion source 120 can provide a negative valve lift cycle, such that the HLA will be unloaded for at least a certain period of time during each engine cycle (regardless of whether the valve actuation motion provided by the first valve actuation motion source 120 is transmitted to the first engine valve 162), allowing the HLA to expand and provide clearance absorption force to eliminate any clearance within the valve mechanism (i.e., the first rocker arm assembly 110 and the first engine valve 162). Figure 10 An example of this situation is illustrated in the figure. Figure 3 A similar approach is used to illustrate exhaust main event 1004 and intake main event 1005, and in this example, auxiliary exhaust valve actuation movement 1002, which can be provided by the first motion source 120. (Note that in this example, with...) Figure 3 Compared to the illustrated engine valve events, all illustrated engine valve events are phased at 65°. However, in this case, the auxiliary exhaust valve actuation motion 1002 includes an HLA refill cycle 1007 from a crank angle of approximately 500° to approximately 560°, wherein in the sub-base circle (i.e., in...) Figure 10A constant lift of approximately -7 mm is provided (below the 0 mm lift axis shown). The amount of negative lift provided during the HLA refill cycle 1007 is determined by the maximum expansion of the first pneumatic assembly 114. That is, the HLA refill cycle 1007 allows the plunger spring 224 to bias the housing 220 and the plunger 222 (as used to realize the first pneumatic assembly 114) apart to the maximum possible extent, i.e., biased apart to the extent allowed by the stroke limiting features 402, 404 in the first pneumatic assembly 114. In this state, the first pneumatic assembly 114 cannot expand further and therefore does not apply a load to any HLA in the first rocker arm assembly 110, which then expands freely to absorb any gaps within the first rocker arm assembly 110 that might otherwise have been absorbed by the plunger spring 224 if further expansion were permitted.

[0043] In another embodiment, to provide the benefits of HLA while avoiding the aforementioned problems caused by the presence of HLA in the first rocker arm assembly 110, the following can be used: Figure 5 The system 500 is depicted. As shown in the figure, system 500 and Figure 1 The system is basically the same as 100, the difference being that... Figure 1 The HLA 148, which was originally positioned between the second output rocker arm 146 and the second valve 164, has been removed and replaced by a first or main HLA 502 positioned between the second aerodynamic component 144 and the second output rocker arm 146. With this configuration, the first HLA 502 is operable to... Figure 1 The HLA 148 absorbs clearance in the valve mechanism established by the second motion source 150, the second rocker arm assembly 140, and the second valve 164 in a similar manner. Furthermore, the first clearance adjuster 502 is operable on the first output rocker arm 116 via a one-way connector 170, thereby minimizing any clearance between the first output rocker arm 116 and the first engine valve 162. However, due to the presence of the one-way connector 170, the constant bias applied by the plunger spring 224 (as part of the first aerodynamic component 114) cannot be applied to the first HLA 502, thereby preventing any interference with the operation of the first HLA 502. In other words, the construction of the first HLA 502 within the second rocker arm assembly 140 allows the first HLA 502 to be operatively connected to the first output rocker arm 116 via the one-way connector 170, thereby enabling operation of both the first output rocker arm 116 and the second rocker arm assembly 140. It should be noted that although the first HLA 502 is illustrated as being disposed within the second output rocker arm 146, it should be understood that the first HLA 502 may be disposed elsewhere within the second rocker arm assembly 140, as long as the first output rocker arm 116 can still be operated via the one-way coupling 170 (i.e., a gap-absorbing force is applied to the higher first output rocker arm).

[0044] about Figures 6 to 8 Examples are given based on Figure 5 A specific embodiment of system 600 is described. System 600 includes a first rocker arm assembly 610 and a second rocker arm assembly 640 configured to actuate a first engine valve 662 and a second engine valve 664, respectively. The first rocker arm assembly 610 includes a first input rocker arm 612 operatively connected to a first actuation member 614, which is in turn operatively connected to a first output rocker arm 616. Similarly, the second rocker arm assembly 640 includes a second input rocker arm 642 operatively connected to a second actuation member 644, which is in turn operatively connected to a second output rocker arm 646. As depicted, all rockers 612, 616, 642, and 646 are half-shaft-mounted rocker arms, but this is not necessary. As further shown in the figures, a one-way coupling 670 is provided between the second output rocker arm 646 and the first output rocker arm 616. In this embodiment, the one-way connector 670 is configured to be non-selectable, i.e., it is "always there," and includes overlapping extensions 672, 674 that are integrally formed in the corresponding output rockers of the second output rocker arm 646 and the first output rocker arm 616 and extend away from these output rockers. As shown in the configuration, valve actuation applied to the second output rocker arm 646 causes the first extension 672 to contact the second extension 674, thereby also actuating the first output rocker arm 616. However, valve actuation applied to the first output rocker arm 616 does not cause the second extension 674 to contact the first extension 672. Figure 6 As further shown, the first output rocker arm 616 and the second output rocker arm 646 each include a rotating element or an e-shaped support 666, 668, which is deployed at its motion application end and configured to contact the corresponding first engine valve 662 and second engine valve 664.

[0045] Figure 7A cross-sectional view of a first rocker arm assembly 610 is illustrated. This first rocker arm assembly typically includes a first input rocker arm 612 operatively connected to first pneumatic members 614, 200', which in turn are operatively connected to a first output rocker arm 616. The first input rocker arm 612 includes a first roller follower 702 configured to contact a first valve actuation motion source, i.e., a cam (not shown). In this configuration, valve actuation motion applied to the first roller follower 702 is transmitted by the first input rocker arm 612 to the first pneumatic members 614, 200'. Depending on the locked / unlocked state of the first pneumatic members 614, 200', the valve actuation motion applied to the first input rocker arm 612 can be transmitted / absorbed (discarded) by the first pneumatic members 614, 200'. When transmitted by the first pneumatic members 614, 200', the valve actuation motion is also applied to the first output rocker arm 616 and applied to a first engine valve (not shown).

[0046] In this embodiment, the connection between the first input rocker arm 612 and the first aerodynamic components 614, 200' is provided by a clearance adjusting screw 704, which terminates near the end of the first aerodynamic components 614, 200' via a hemispherical ball joint 244. Using known techniques, a clearance adjusting screw 407 can be used to set a clearance within the valve mechanism including the first rocker arm assembly 601, which can be held by a lock nut 706. Furthermore, as indicated by the reference numerals, the first aerodynamic components 614, 200' include a reference... Figure 4 The described aerodynamic component 200' is characterized such that the first input rocker arm 612 and the first output rocker arm 616 are biased away from each other, while keeping the first input rocker arm 612 in contact with the first valve actuation motion source (not shown) and the first output rocker arm 616 in contact with the first engine valve (not shown) via the rotating member 666.

[0047] It should be noted that Figure 7 The illustrated implementation includes stroke-limiting features of overlapping shoulder 402 and flange 404, thereby ensuring that plunger 222 does not overextend relative to housing 220.

[0048] Figure 8 A cross-sectional view of a second rocker arm assembly 640 is illustrated. This second rocker arm assembly typically includes a second input rocker arm 642 operatively connected to second pneumatic components 644, 200, which in turn are operatively connected to a second output rocker arm 646. The second input rocker arm 642 includes a second roller follower 802 configured to contact a second valve actuation motion source, i.e., a cam (not shown). In this case, as indicated by the reference numerals, the second pneumatic components 644, 200 include a reference... Figure 2The described aerodynamic component 200 is characterized such that the second input rocker arm 642 and the second output rocker arm 646 are biased away from each other. This configuration allows the valve actuation motion applied to the second roller follower 802 to be transmitted by the second input rocker arm 642 to the second aerodynamic components 644, 200. Depending on the locked / unlocked state of the second aerodynamic components 644, 200, the valve actuation motion applied to the second input rocker arm 642 can be transmitted / absorbed (discarded) by the first aerodynamic components 644, 200. When transmitted by the second aerodynamic components 644, 200, the valve actuation motion is also applied to the second output rocker arm 646 and to the first engine valve (not shown).

[0049] and Figure 5 The implementation scheme is consistent, but the control of the gap adjustment in the second rocker arm assembly 640 is handled in a different manner than that in the first rocker arm assembly 610. For example, in Figure 7 The position of the gap adjusting screw 704 is depicted. The connection between the second input rocker arm 642 and the second pneumatic components 644, 200 is provided by a plug 804, which in this case provides a concave surface 806 configured to complementaryly receive a hemispherical ball joint disposed on the end cap of the second pneumatic components 644, 200. Conversely, gap adjustment within the second rocker arm assembly 640 is provided by a first HLA 502 operatively connected to both the second pneumatic component 644 and the second output rocker arm 646, as shown (and according to...). Figure 5 (Implementation scheme of the embodiment). According to known art, the first HLA 502 includes an HLA housing 808 configured to be threadedly received within an HLA bore 810 formed in the nose of a second output rocker arm 646. An HLA insert 812 is slidably received in an HLA chamber 814 formed by the bore in the HLA housing 808 and the end surface of the HLA bore 810. The HLA insert 812 forms an orifice 816 closed by a check disc 818 and a check spring 820 disposed in a high-pressure chamber 822 formed by the space between the HLA housing 808 and the HLA insert 812. As is known in the art, the check disc 818 can be equivalently implemented as a check ball.

[0050] As is known in the art, when no valve actuation load is applied to the second rocker arm assembly 640, the pressurized hydraulic fluid supplied to the HLA chamber 814 (from a pressurized hydraulic fluid supply source via a suitable hydraulic passage formed in the second output rocker arm 646; both not shown) overcomes the bias applied to the check disc 818 by the check spring 820, causing hydraulic fluid to flow from the HLA chamber 814 into the high-pressure chamber 822. As is further known in the art, the biasing force generated by this hydraulic fluid flow causes the HLA housing 808 and the HLA insert 812 to travel away from each other, such that any clearance present in the valve mechanism including the second rocker arm assembly 640 is absorbed (i.e., substantially reduced or eliminated). Furthermore, as referenced... Figure 5 The biasing force applied by the first HLA 502 is also transmitted to the first output rocker arm 616 by the one-way connector 670, thereby absorbing any additional clearance space between the first output rocker arm 616 and the first engine valve 662.

[0051] although Figure 8 Not illustrated (due to the housing 220 and plunger 222 relative to each other) Figure 8 (rotation of the cross-sectional plane), but the stroke limiting features of the overlapping shoulder 402 and flange 404 are preferably incorporated into the first aerodynamic component 644 to again prevent the plunger 222 from over-extending relative to the housing 220.

[0052] Although with Figures 5 to 8 A consistent system advantageously allows the use of HLA to absorb clearances in valve actuation systems, but may introduce further disadvantages. More specifically, and again refer to... Figure 5 During certain valve actuations (e.g., primary valve actuation provided by the second motion source 150), the rates at which the first engine valve 162 and the second engine valve 164 reposition themselves (so-called valve recess rates) may differ. For example, if the first engine valve 162 is fully repositioned before the second engine valve 164 is fully repositioned after the primary valve actuation, any clearance adjustment provided by the first HLA 502 will be set by the first engine valve 162 (via one-way coupling 170), resulting in a gap between the second output rocker arm 146 and the second engine valve 164.

[0053] To address this possibility, one could, for example... Figure 9 Modifications shown Figure 5 System 500. Figure 9 The valve actuation system 900 described is... Figure 5The system shown is the same as 500, except that, in addition to the first HLA 502, a second or auxiliary HLA 902 is provided between the second output rocker arm 146 and the second engine valve 164. With this configuration, the second HLA 902 can accommodate any gap space between the second output rocker arm 146 and the second engine valve 164, which is caused by different valve retraction rates and operations of the first HLA 502 as described above.

[0054] Those skilled in the art will understand that connecting the first HLA 502 and the second HLA 902 in series will tend to result in the first HLA 502 and the second HLA 902 antagonizing each other. To prevent any undesirable operating conditions that might arise due to contention between the first HLA 502 and the second HLA 902, the second HLA 902 can be configured to generate a lower anti-gap bias force than that provided by the first HLA 502. This can be achieved by configuring the HLA housing and HLA insert of the second HLA 902 to have a smaller diameter than the corresponding component in the first HLA 502, although operating with the same pressurized hydraulic fluid supply. This configuration allows the first HLA 502 to expand to a point determined by the first output rocker arm 116 / first engine valve 162, which also allows the second HLA 902 to expand according to any gap formed between the second output rocker arm 146 and the second engine valve 164.

[0055] like Figure 9 As shown in the configuration, the first HLA 502 and the second HLA 902 remain under compressive load under all operating conditions, thereby preventing any undesirable "lifting" (over-stretching) of the first HLA 502 and the second HLA 902. For example, and continuing to refer to Figure 9 When the engine is expected to generate positive power, the first aerodynamic component 114 operates in its unlocked / motion absorption state and the second aerodynamic component 144 operates in its locked / motion transmission state, such that auxiliary valve actuation motion is not transmitted to the first engine valve 162, while the main valve actuation motion is transmitted to both the first valve 162 and the second valve 164. In this case, both the first HLA 502 and the second HLA 902 are continuously in the main motion load path (i.e., from the second motion source 150 to the second engine valve 164), thus preventing overextension.

[0056] As another example, in the case where a combined valve actuation motion from the first motion source 120 and the second motion source 150 is desired (e.g., compression release engine braking, IEGR, VVA, EEVO, LIVC, etc.), the first aerodynamic component 114 operates in its locked / motion transmission state and the second aerodynamic component 144 also operates in its locked / motion transmission state, such that auxiliary valve actuation motion is transmitted to the first engine valve 162, and primary valve actuation motion is transmitted to both the first valve 162 and the second valve 164. In this case, when the second motion source 150 does not provide any valve actuation motion via the second rocker arm assembly 140 (e.g., where the cam providing the second motion source 150 is at the base circle) and the first motion source 120 provides valve actuation motion via the first rocker arm assembly 110, a component of the one-way coupling 170 will be formed ( Figure 6 The chance of a gap appearing between the overlapping extensions 672 and 674 in the example. Figure 3 An example illustrating this state is provided where, at a crank angle of 0°, no primary exhaust valve actuation movement 304 is provided; instead, a first compression release valve actuation movement 306 is provided. In this case, although there is separation between the components forming the one-way coupling 170, the first HLA 502 and the second HLA 902 remain in a compressed state by means of, for example, the plunger spring 224 present in the first aerodynamic component 114.

[0057] As yet another example, where only auxiliary valve actuation of the engine is desired (e.g., 1.5-stroke or 2-stroke compression release engine braking), the first aerodynamic component 114 operates in its locked / motion transmission state and the second aerodynamic component 144 operates in its unlocked / motion absorption state, such that auxiliary valve actuation motion is transmitted to the first engine valve 162, while primary valve actuation motion is not transmitted to either the first valve 162 or the second valve 164. In this case, valve actuation motion from the second motion source 150 is not transmitted via the second rocker arm assembly 140, i.e., no compression is applied to the first HLA 502 or the second HLA 902 by means of any primary valve actuation motion. However, again, by means of the plunger spring 224 present in the first aerodynamic component 114, the first HLA 502 and the second HLA 902 will remain in a compressed state.

Claims

1. A system for actuating at least two engine valves associated with a cylinder of an internal combustion engine, the system comprising: A first rocker arm assembly, operatively connected to a first valve actuation motion source and to a first engine valve of the at least two engine valves, includes a first actuation component arranged in series with a first input rocker arm and a first output rocker arm. The first input rocker arm is configured to receive a first valve actuation motion from the first valve actuation motion source, and the first output rocker arm is configured to deliver the first valve actuation motion to the first engine valve. The first actuation component is operable in a motion absorption state to prevent the first valve actuation motion from being transmitted from the first input rocker arm to the first output rocker arm, and operable in a motion transmission state to transmit the first valve actuation motion from the first input rocker arm to the first output rocker arm. A second rocker arm assembly, operatively connected to a second valve actuation source and to a second engine valve of the at least two engine valves, includes a second actuating component arranged in series with a second input rocker arm and a second output rocker arm. The second input rocker arm is configured to receive a second valve actuation motion from the second valve actuation source, and the second output rocker arm is configured to deliver the second valve actuation motion to the second engine valve. The second actuating component is operable in a motion absorption state to prevent the second valve actuation motion from being transmitted from the second input rocker arm to the second output rocker arm, and operable in a motion transmission state to transmit the second valve actuation motion from the second input rocker arm to the second output rocker arm. as well as A one-way connection mechanism is disposed between the first output rocker arm and the second output rocker arm, such that the second valve actuation motion is transmitted from the second output rocker arm to the first output rocker arm, and the first valve actuation motion is not transmitted from the first output rocker arm to the second output rocker arm. The main hydraulic gap adjuster is incorporated in the second rocker arm assembly, such that the main hydraulic gap adjuster operates the first output rocker arm via the one-way coupling mechanism.

2. The system according to claim 1, wherein the main hydraulic gap adjuster is disposed in the second output rocker arm.

3. The system of claim 1, wherein each of the first input rocker arm, the first output rocker arm, the second input rocker arm, and the second output rocker arm comprises a shaft-mounted half-rocker arm.

4. The system of claim 1, wherein the unidirectional coupling mechanism includes a second extension forming part of the at least one second output rocker arm and a first extension forming part of the first output rocker arm, and wherein the first extension and the second extension are configured to contact each other.

5. The system according to claim 1, wherein the first aerodynamic component includes a hydraulically controlled locking mechanism.

6. The system of claim 1, wherein the first aerodynamic component includes a first spring that biases the first input rocker arm toward the first valve actuation motion source and biases the first output rocker arm toward the first engine valve.

7. The system of claim 1, wherein the first aerodynamic component has a longitudinal range sufficient to accommodate the motion applied to the first output rocker arm via the one-way coupling mechanism.

8. The system of claim 1, wherein the first aerodynamic component is configured to have a limited stroke.

9. The system according to claim 1, further comprising: An auxiliary hydraulic clearance adjuster is disposed between the second output rocker arm and the second engine valve.

10. The system according to claim 9, wherein the auxiliary anti-gap force provided by the auxiliary hydraulic gap adjuster is less than the main anti-gap force provided by the main hydraulic gap adjuster.

11. The system of claim 1, wherein the second aerodynamic component comprises a hydraulically controlled locking mechanism.

12. The system of claim 1, wherein the second aerodynamic component includes a second spring that biases the first input rocker arm toward the second valve actuation motion source and biases the second output rocker arm toward the second engine valve.

13. The system of claim 1, wherein the second aerodynamic component is configured to have a limited stroke.

14. A system for actuating at least two engine valves associated with a cylinder of an internal combustion engine, the system comprising: A first rocker arm assembly, operatively connected to a first valve actuation motion source and to a first engine valve of the at least two engine valves, includes a first actuation component arranged in series with a first input rocker arm and a first output rocker arm. The first input rocker arm is configured to receive a first valve actuation motion from the first valve actuation motion source, and the first output rocker arm is configured to deliver the first valve actuation motion to the first engine valve. The first actuation component is operable in a motion absorption state to prevent the first valve actuation motion from being transmitted from the first input rocker arm to the first output rocker arm, and operable in a motion transmission state to transmit the first valve actuation motion from the first input rocker arm to the first output rocker arm. A second rocker arm assembly is operatively connected to a second valve actuation motion source and to a second engine valve of the at least two engine valves. The second rocker arm assembly includes at least one second rocker arm configured to receive a second valve actuation motion from the second valve actuation motion source and configured to impart the second valve actuation motion to the second engine valve. as well as A one-way connection mechanism is disposed between the first output rocker arm and the at least one second rocker arm, such that the second valve actuation motion is transmitted from the at least one second rocker arm to the first output rocker arm, and the first valve actuation motion is not transmitted from the first output rocker arm to the at least one second rocker arm. The first rocker arm assembly includes a hydraulic gap adjuster, and The first valve actuation motion source includes a refill cycle, which includes a subbase circle lift configured to eliminate the load placed on the hydraulic clearance adjuster by expanding the first aerodynamic component.

15. The system of claim 14, wherein the at least one second rocker arm comprises: A second aerodynamic component is arranged in series with a second input rocker arm and a second output rocker arm. The second input rocker arm is configured to receive the second valve actuation motion from the second valve actuation motion source, and the second output rocker arm is configured to deliver the second valve actuation motion to the second engine valve. The second aerodynamic component is operable in a motion absorption state to prevent the second valve actuation motion from being transmitted from the second input rocker arm to the second output rocker arm, and is operable in a motion transmission state to transmit the second valve actuation motion from the second input rocker arm to the second output rocker arm.

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