Valve actuation system including a rocker assembly having a one-way coupling therebetween

Abstract

A system for actuating at least two engine valves includes a first rocker assembly operatively connected to a first source of valve actuation motion and to a first engine valve. The first rocker assembly includes a first lost motion component disposed in series with a first input rocker and a first output rocker. A second rocker assembly operatively connected to a second source of valve actuation motion and to a second engine valve. The second rocker assembly includes at least one second rocker. The system further includes a one-way coupling mechanism disposed between the first output rocker and the at least one second rocker such that the second valve actuation motion is transmitted from the at least one second rocker to the first output rocker and the first valve actuation motion is not transmitted from the first output rocker to the at least one second rocker.

Description

[Technical Field]

[0001] The present disclosure relates generally to internal combustion engines, and more particularly to a valve actuation system including a rocker assembly having a one-way coupling therebetween. [Background technology]

[0002] Valve actuation in an internal combustion engine is required for the engine to operate. Typically, valve actuation forces to open engine valves (i.e., intake, exhaust, or auxiliary engine valves) are transmitted by a valve train, and such valve actuation forces may be provided by a primary motion source and / or an auxiliary motion source. As used herein, the description "primary" refers to so-called primary event engine valve movements, i.e., valve movements used during the production of positive power when fuel is combusted in the engine cylinder to provide net engine output, while the description "auxiliary" refers to other engine valve movements intended to replace or in addition to the production of positive power (e.g., compression release braking, bleeder braking, cylinder decompression, cylinder deactivation, brake gas recirculation (BGR), etc.) or in addition to the production of positive power (e.g., internal exhaust gas recirculation (IEGR), variable valve actuations (VVA), early exhaust valve opening (EEVO), late intake valve closing (LIVC), swirl control, etc.).

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

[0004] Given a fixed cam profile, one method of adjusting valve timing and lift has been to provide a “lost motion” or variable-length device in the valvetrain linkage between a given engine valve and its corresponding cam. Lost motion is a term applied to the field of engineering solutions for modifying valve motion prescribed by a cam profile with 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-producing and / or auxiliary motion, as needed. A variable-length system can then be included in the valvetrain linkage intermediate the valve to be opened and the cam providing the maximum motion to reduce or eliminate some or all of the motion imparted to the valve by the cam. Typically, such lost motion devices are controllable between a “locked” or motion-transmitting state and an “unlocked” or motion-absorbing state. During the locked state, the lost motion device is maintained in a substantially rigid configuration (with allowance for lash adjustment) so that valve actuation motion applied to it is transmitted to the corresponding engine valve. On the other hand, while in the unlocked state, the lost motion device is able to absorb or avoid, i.e., "lose," 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 features continue to be developed to provide greater valve actuation functionality and flexibility. However, increased cost, packaging, and size are factors that can often determine the desirability of such engine valve actuation systems. A valve actuation system with lost motion components that overcomes these limitations while still providing various valve actuation functionality and flexibility would represent a welcome advancement in the art. Summary of the Invention

[0006] This disclosure describes various embodiments of a valve actuation system for actuating at least one engine valve in an internal combustion engine. In one embodiment, a system for actuating at least two engine valves associated with a cylinder of an internal combustion engine includes a first rocker assembly operably connected to a first valve actuation motion source and a first engine valve of the at least two engine valves. The first rocker assembly includes a first lost motion component disposed in series with a first input rocker and a first output rocker, the first input rocker configured to receive the first valve actuation motion from the first valve actuation motion source and the first output rocker configured to impart the first valve actuation motion to the first engine valve. The first lost motion component is operable in a motion-absorbing state to prevent transmission of the first valve actuation motion from the first input rocker to the first output rocker and in a motion-transmitting state to transmit the first valve actuation motion from the first input rocker to the first output rocker. A second rocker assembly is operably connected to a second valve actuation motion source and a second engine valve of the at least two engine valves. The second rocker assembly includes at least one second rocker configured to receive second valve actuation motion from a second valve actuation motion source and to impart the second valve actuation motion to a second engine valve. The system further includes a one-way coupling mechanism disposed between the first output rocker and the at least one second rocker such that the second valve actuation motion is transmitted from the at least one second rocker to the first output rocker and the first valve actuation motion is not transmitted from the first output rocker to the at least one second rocker.

[0007] In one embodiment, the first output rocker and / or the at least one second rocker includes a hydraulic lash adjuster.

[0008] In one embodiment, the first rocker assembly is configured to operate as a Type II rocker or as a Type III rocker.

[0009] In one embodiment, the first input rocker and the first output rocker each include a half rocker attached to the shaft. Further to this embodiment, the first output rocker may include lateral arms defining a central opening, the central opening configured to receive the first input rocker between the lateral arms. In an alternative embodiment, the first output rocker and the first input rocker are configured to be positioned adjacent to one another.

[0010] In one embodiment, the at least one second rocker includes a half rocker attached to the shaft.

[0011] In one embodiment, the one-way coupling mechanism comprises a coupling arm forming part of the at least one second rocker and a coupling contact surface forming part of the first output rocker, the coupling arm and the coupling contact surface being configured to contact each other.

[0012] In one embodiment, the first lost motion component includes a hydraulically controlled locking mechanism.

[0013] In another embodiment, the at least one second rocker includes a second lost motion component disposed in series with the second input rocker and the second output rocker. The second input rocker is configured to receive the second valve-actuating motion from a second valve-actuating motion source, and the second output rocker is configured to impart the second valve-actuating motion to a second engine valve. The second lost motion component is operable in a motion-absorbing state to prevent transmission of the second valve-actuating motion from the second input rocker to the second output rocker, and in a motion-transmitting state to transmit the second valve-actuating motion from the second input rocker to the second output rocker.

[0014] In one embodiment, the second output rocker includes a hydraulic lash adjuster.

[0015] In one embodiment, the second rocker assembly is configured to operate as a Type II rocker. In addition to this embodiment, the first rocker assembly is also configured to operate as a Type II rocker.

[0016] In one embodiment, the second rocker assembly is configured to operate as a Type III rocker. In addition to this embodiment, the first rocker assembly is also configured to operate as a Type III rocker.

[0017] In one embodiment, the second input rocker and the second output rocker each include a half rocker attached to the shaft. Further to this embodiment, the second output rocker includes lateral arms defining a central opening, the central opening configured to receive the second input rocker between the lateral arms. In an alternative embodiment, the second output rocker and the second input rocker are configured to be positioned adjacent to one another.

[0018] In one embodiment, the one-way coupling comprises a coupling arm forming part of the second output rocker and a coupling contact surface forming part of the first output rocker, the coupling arm and the coupling contact surface being configured to contact each other.

[0019] In one embodiment, the second lost motion component includes a hydraulically controlled locking mechanism. [Brief explanation of the drawings]

[0020] The foregoing and other features and advantages are discussed in detail in the following non-limiting description of specific embodiments, taken in conjunction with the accompanying drawings. [Figure 1]FIG. 1 is a schematic diagram illustrating an embodiment of a valve actuation system including a lost motion component according to the present disclosure. [Figure 2] FIG. 1 is a schematic diagram illustrating an embodiment of a valve actuation system including a lost motion component according to the present disclosure. [Figure 3] FIG. 1 is a cross-sectional view of an example of a lost motion component that may be used to implement various embodiments described herein. [Figure 3A] 10A-10C are cross-sectional views of alternative examples of lost motion components that may be used to implement various embodiments described herein. [Figure 4] FIG. 2 illustrates a first implementation of the valve actuation system according to the first embodiment of FIG. 1. [Figure 5] FIG. 2 illustrates a first implementation of the valve actuation system according to the first embodiment of FIG. 1. [Figure 6] FIG. 2 illustrates a first implementation of the valve actuation system according to the first embodiment of FIG. 1. [Figure 7] FIG. 3 illustrates a second implementation of the valve actuation system according to the second embodiment of FIG. 2. [Figure 8] FIG. 3 illustrates a second implementation of the valve actuation system according to the second embodiment of FIG. 2. [Figure 9] FIG. 3 shows a third implementation of the valve actuation system also according to the second embodiment of FIG. 2. [Figure 10] FIG. 3 shows a third implementation of the valve actuation system also according to the second embodiment of FIG. 2. [Figure 11] FIG. 3 shows a third implementation of the valve actuation system also according to the second embodiment of FIG. 2. [Figure 12] 9 is a cross-sectional view of the implementation of FIGS. 4-6 or the implementation of FIGS. 7 and 8, in which the alternative lost motion component of FIG. 3A is used. [Figure 13] 9 is a cross-sectional view of the implementation of FIGS. 4-6 or the implementation of FIGS. 7 and 8, in which the alternative lost motion component of FIG. 3A is used. [Figure 14] 9 is a cross-sectional view of the implementation of FIGS. 4-6 or the implementation of FIGS. 7 and 8, in which the alternative lost motion component of FIG. 3A is used. [Figure 15] 9 is a cross-sectional view of the implementation of FIGS. 4-6 or the implementation of FIGS. 7 and 8, in which the alternative lost motion component of FIG. 3A is used. [Figure 16] 9 is a cross-sectional view of the implementation of FIGS. 4-6 or the implementation of FIGS. 7 and 8, in which the alternative lost motion component of FIG. 3A is used. [Figure 17] 9 is a cross-sectional view of the implementation of FIGS. 4-6 or the implementation of FIGS. 7 and 8, in which the alternative lost motion component of FIG. 3A is used. [Figure 18] 9 is a cross-sectional view of the implementation of FIGS. 4-6 or the implementation of FIGS. 7 and 8, in which the alternative lost motion component of FIG. 3A is used. [Figure 19] 9 is a cross-sectional view of the implementation of FIGS. 4-6 or the implementation of FIGS. 7 and 8, in which the alternative lost motion component of FIG. 3A is used. [Figure 20] 9 is a cross-sectional view of the implementation of FIGS. 4-6 or the implementation of FIGS. 7 and 8, in which the alternative lost motion component of FIG. 3A is used. [Figure 21] 9 is a cross-sectional view of the implementation of FIGS. 4-6 or the implementation of FIGS. 7 and 8, in which the alternative lost motion component of FIG. 3A is used. DETAILED DESCRIPTION OF THE INVENTION

[0021] As used herein, phrases substantially similar to "at least one of A, B, or C" are intended to be construed disjunctively, i.e., requiring A or B or C, or any combination thereof, unless otherwise stated or implied by context. Further, phrases substantially similar to "at least one of A, B, and C" are intended to be conjunctively, i.e., requiring at least one of A, at least one of B, and at least one of C, unless otherwise stated or implied by context. Further, the term "substantially" or similar words requiring subjective comparison are intended to mean "within manufacturing tolerances," unless otherwise stated or implied by context.

[0022] As used herein, the term "operably connected" is understood to refer to a functional relationship between at least two components, i.e., that the claimed components must be connected (potentially including the presence of intervening elements or components) such that the components perform the indicated function.

[0023] 1 schematically illustrates a first embodiment of a valve actuation system 100 comprising a first rocker assembly 110 and a second rocker assembly 140. As shown, the first rocker assembly 110 is operably connected to a first source of valve actuation motion 120, and the second rocker assembly 140 is operably connected to a second source of valve actuation motion 150. A first engine valve 162 and a second engine valve 164 (both of which may be intake or exhaust valves, for example) are associated with a cylinder 160 of an internal combustion engine, with the valves 162, 164 operably connected to respective ones of the first rocker assembly 110 and the second rocker assembly 140. In this manner, first rocker assembly 110 and second rocker assembly 140 operate to actuate (i.e., open and close) engine valves 162, 164 as commanded by first valve actuation motion source 120 and second valve actuation motion source 150 (and subject to the action of incorporated lost motion components), as described in further detail below. Although only a single cylinder 160 is illustrated in Figure 1, it will be understood that an internal combustion engine may include more than one cylinder, and the valve actuation systems described herein are applicable to any number of cylinders for a given internal combustion engine.

[0024] Valve actuation motion sources 120, 150 may comprise any combination of known elements capable of providing valve actuation motion, such as cams. Each of valve actuation motion sources 120, 150 may be dedicated to providing a main exhaust motion, a main intake motion, an auxiliary motion, or a combination of main exhaust or main intake motion along with auxiliary motion. For example, in one embodiment, first motion source 120 is configured to provide the auxiliary valve actuation motion, and second motion source 150 is configured to provide the main valve actuation motion (either exhaust or intake).

[0025] In this first embodiment, the first rocker assembly 110 comprises a first input rocker 112, a first lost motion component 114, and a first output rocker 116 arranged in series. As used herein, the term "series" refers to the transmission of valve-actuating motion; i.e., the components are in series to the extent that they transmit valve-actuating motion from one to the other along a path from a source of valve-actuating motion to one or more engine valves, at least for exhaust. In particular, the first input rocker 112 is operably connected to a first source of valve-actuating motion 120, the first output rocker 116 is operably connected to a first engine valve 162, and the first lost motion component 114 is operably connected and disposed between the first input rocker 112 and the first output rocker 116. The first input rocker 112 and the first output rocker 116 may comprise center-pivot rocker arms or Type III rocker arms; various implementations based on center-pivot rocker arms are described in further detail below. However, it is understood that the first input rocker 112 and the first output rocker 116 may also be implemented using end-pivot rocker arms or Type II rocker arms. Optionally (as shown by dashed lines), a first hydraulic lash adjuster (HLA) 118 may be included in the first rocker assembly 110. In the illustrated example, the first HLA 118 is disposed within the first output rocker 116, which may include hydraulic passages (known in the art and not shown) suitable for providing hydraulic fluid to the first HLA 118. It is understood that the first HLA 118 may instead be disposed as part of the other components 112, 114 that make up the first rocker assembly 110.

[0026] 1, an engine controller 180 may be provided and operatively connected to the first lost motion component 114. The engine controller 180 may: 1stThe engine controller 180 may comprise any electronic, mechanical, hydraulic, electro-hydraulic, or other type of control device for controlling the operation of the lost motion mechanism 114, i.e., for switching between its respective locked and unlocked states as described above. For example, the engine controller 180 may be implemented by a microprocessor and corresponding memory storing executable instructions used to implement the necessary control functions, including those described below, as known in the art. It will be understood that other functionally equivalent implementations of the engine controller 180, such as a suitably programmed application specific integrated circuit (ASIC), may equally be used. Furthermore, the engine controller 180 may be configured to control the engine 180 so that the engine controller 180 1st It may include peripheral devices intermediate the engine controller 180 and the first lost motion component 114 that allow control over the operating state of the lost motion device 114 to be achieved. For example, 1st If the lost motion device 114 is a hydraulically controlled mechanism (ie, responsive to the absence or application of hydraulic fluid to an input), such peripheral devices may include suitable solenoids.

[0027] 1 , control of the first lost motion component 114 by the engine controller 180 is provided directly to the first lost motion component 114. However, in practice, such control may be provided via a path through at least one of the adjacent input rocker 112 or output rocker 116. For example, in various embodiments described herein, such control is provided through the use of hydraulic fluid supplied, under control of the engine controller 180, via one or more fluid passages formed in the first input rocker 112 or the first output rocker 116. However, as will be understood by those skilled in the art, other types of control schemes may equally be employed for this purpose.

[0028] 1 , the second rocker assembly 140 includes a second rocker 146 operably connected to a second valve actuation motion source 150 and a second engine valve 164. Again, a second optional HLA 148 may be included in the second rocker assembly 140. In the illustrated example, the second HLA 148 is disposed within the second rocker 146, which may include suitable hydraulic passages (not shown) for supplying hydraulic fluid to the second HLA 148. Note that because the second rocker assembly 140 does not include lost motion components, it may not be necessary to ensure controlled operation (i.e., stroke limiting) as described above with respect to the first HLA 118.

[0029] A feature of the illustrated first embodiment is the provision of a one-way coupling (OWC) 170 between the second rocker 146 of the second rocker assembly 140 and the first output rocker 116 of the first rocker assembly 110. The second rocker 146 can drive the first output rocker 116, but not vice versa, as indicated by the one-way arrow shown in FIG. 1 between the second rocker 146, the one-way coupling 170, and the first output rocker 116. That is, the presence of the one-way coupling 170 allows the valve actuation provided by the second valving motion source 150 to be applied to the first output rocker 116, but does not allow the valve actuation provided by the first valving motion source 120 to be applied to the second rocker 146. In one embodiment, the one-way coupling 170 is implemented using a fixed element such that the one-way coupling 170 is “always there,” i.e., the one-way coupling 170 is not selectable. However, it is understood that the one-way coupling 170 may be implemented using alternative elements such as a hydraulically controlled actuator.

[0030] 1 , the valve actuation system 100 provides various options for actuating the engine valves 162, 164. For example, if the second valve actuation motion source 150 provides the main valve actuation motion and the first valve actuation motion source 120 provides the auxiliary valve actuation motion, the first lost motion 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 112 is not transmitted by the first lost motion component 114 to the first output rocker 116, and thereby to the first engine valve 162. In this case, the main valve actuation motion applied to the second rocker 146 is applied to the second engine valve 164. Furthermore, by virtue of the one-way coupling 170, the main valve actuation motion applied to the second rocker 146 is also applied to the first output rocker 116, and thereby to the first engine valve 162. Such control of the engine valves 162, 164 may be used, for example, to implement positive power generating operation of the engine.

[0031] Alternatively, the first lost motion component 114 can be controlled to its locked or motion-transmitting state such that auxiliary valve actuation motion applied to the first input rocker 112 is transferred by the first lost motion component 114 to the first output rocker 116 and thereby to the first engine valve 162. In this case, the second rocker 146 and one-way coupling 170 continue to operate as described above, such that main valve actuation motion is provided to both the first engine valve 162 and the second engine valve 164, but auxiliary valve actuation motion is provided only to the first engine valve 162. Such control of the engine valves 162, 164 can be used, for example, to implement conventional four-stroke compression-release engine braking operation of the engine, or to provide other additional auxiliary valve actuation motion of the type described above.

[0032] Referring now to FIG. 2, a second embodiment of a valve actuation system 200 is shown, comprising a first rocker assembly 110 and a second rocker assembly 240. The valve actuation system 200 of FIG. 2 differs from the valve actuation system 100 of FIG. 1 primarily in the components forming the second rocker assembly 240 of FIG. 2. More specifically, the second rocker assembly 240 comprises a second input rocker 242, a second lost motion component 244, and a second output rocker 246 arranged in series. In particular, the second input rocker 242 is operably connected to the second valve actuation motion source 150, the second output rocker 246 is operably connected to the second engine valve 162, and the lost motion component 244 is operably connected and disposed between the second input rocker 242 and the second output rocker 246. The second input rocker 242 and the second output rocker 246 may include center pivot rocker arms; various implementations based on center pivot rocker arms are described in further detail below. Again, it is understood that the first input rocker 112 and the first output rocker 116 may be implemented using end-pivot rocker arms or Type II rocker arms. Optionally, a second hydraulic lash adjuster (HLA) 248 may be included in the second rocker assembly 240. In the illustrated example, the second HLA 248 is disposed within the second output rocker 246, which may include suitable hydraulic passages (not shown) for supplying hydraulic fluid to the second HLA 248. It is understood that the second HLA 248 may instead be disposed as part of the other components 242, 244 that make up the second rocker assembly 110. Similar to the first HLA 118 in the first embodiment, if a second lost motion component 244 is present within the second rocker assembly 240, it may be desirable to control the operation of the second HLA 248 to prevent overextension of the second engine valve 164.Alternatively, again, prevention of engine valve overextension due to operation of HLA 248 can be provided instead by a stroke limit built into second lost motion component 244 and a biasing force provided by first lost motion component 224 sufficient to prevent overextension of HLA 248.

[0033] With the addition of second lost motion component 244 to second rocker assembly 240, controller 280 of the second embodiment is substantially identical to controller 180 of the first embodiment, except that controller 280 is modified so that controller 280 is also operatively coupled to second lost motion component 244. Again, while controller 280 is shown as directly controlling second lost motion component 244, it will be appreciated that such control may be mediated through paths provided in adjacent components, such as second input rocker 242 and / or second output rocker 246.

[0034] Furthermore, the operation of the one-way coupling 270 of the second embodiment is substantially identical to the operation of the one-way coupling 170 of the first embodiment, except that the one-way coupling 270 is disposed between the second output rocker 246 and the first output rocker 116 as shown in FIG. 2 .

[0035] 2 , the valve actuation system 100 provides various options for actuating the engine valves 162, 164. For example, again, if 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 lost motion 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 112 is not transmitted by the first lost motion component 114 to the first output rocker 116 and, consequently, to the first engine valve 162. In addition, the second lost motion component 244 can likewise be controlled to be in its unlocked or motion-absorbing state such that the primary valve actuation motion applied to the second input rocker 242 is not transmitted by the second lost motion component 244 to the second output rocker 246, and thus to the second engine valve 164 (or to the first engine valve via the one-way coupling 270). Such control of the engine valves 162, 164 may be used, for example, to implement cylinder deactivation (CDA) operation of the engine.

[0036] Alternatively, based on this same example, if the first lost motion component 114 is again operated in its unlocked / motion-absorbing state and the second lost motion component 244 is operated in its locked / motion-transmitting state, the auxiliary valve actuation motion is not transferred to the first engine valve 162, but the main valve actuation motion is transferred to both the first valve 162 and the second valve 164. Such control of the engine valves 162, 164 may be used, for example, to implement positive power generating operation of the engine.

[0037] In another alternative, based on this same example, if the first lost motion component 114 is operated in its locked / motion transmitting state and the second lost motion component 244 is operated in its locked / motion transmitting state, the auxiliary valve actuation motion is transmitted to the first engine valve 162 and the main valve actuation motion is transmitted to both the first valve 162 and the second valve 164. Such control of the engine valves 162, 164 may be used, for example, to implement conventional four-stroke compression-release engine braking operation of the engine or to provide other additional auxiliary valve actuation motion of the type described above.

[0038] In yet another alternative, based on this same example, if the first lost motion component 114 is operated in its locked / motion-transmitting state and the second lost motion component 244 is operated in its unlocked / motion-absorbing state, auxiliary valve actuation motion is transmitted to the first engine valve 162, but main valve actuation motion is not transmitted to either the first valve 162 or the second valve 164. Such control of the engine valves 162, 164 can be used to implement operating modes in which auxiliary valve actuation, rather than main valve actuation, is desired. For example, such operating modes may include so-called two-stroke or one-and-a-half-stroke compression-release engine braking operation of the engine.

[0039] FIG. 3 illustrates an example of a lost motion component 300 that may be used with the valve actuation systems 100, 200 shown in FIGS. 1 and 2, as well as various specific implementations described below in connection with FIGS. 4-11. The lost motion component 300 is shown in cross section to better illustrate the hydraulically controlled locking mechanism 310, which constitutes a subassembly of the lost motion component 300 and is disposed between the housing 320 and the plunger 322. While the housing 320 may be formed as a single element, in the example shown in FIG. 3, the closed end of the housing 320 is provided by an end cap 321 attached to the housing 320. A plunger spring 324 is disposed outside the housing 320 and plunger 322. In the illustrated embodiment, the plunger spring 324 is disposed between a flange 326 formed on or attached to the outer surface of the plunger 322 and a shoulder 328 formed within the housing 320. In this manner, plunger spring 324 biases housing 320 and plunger 322 away from each other. In one embodiment, the biasing force exerted by plunger spring 324 is high enough to prevent extension of any hydraulic lash adjuster located in the same valve train as lost motion component 300. Furthermore, although plunger spring 324 is located outside of housing 320 in the illustrated example, it should be understood that plunger spring 324 could also be located within housing 320 to provide a similar bias as described above.

[0040] As mentioned above, plunger spring 324 is strong enough to prevent extension of any hydraulic lash adjuster located in the same valve train as lost motion component 300. However, this can lead to collapse of the hydraulic lash adjuster if the biasing force of plunger spring 324 is too strong. To prevent this, a stroke limit may be provided within lost motion component 300 to prevent overextension of housing 320 and plunger 322 away from each other, which could otherwise exert sufficient compressive force on the hydraulic lash adjuster to collapse it. For example, although not shown in FIG. 3 , the end of plunger 322 adjacent plunger cap 343 may include a radially extending lip or flange configured to engage shoulder 331 formed on a surface defining housing bore 330. Thus, when plunger 322 is urged outward from housing 320 by plunger spring 324, engagement of the radially extending lip or flange with shoulder 331 prevents plunger 322 from moving further outward from housing 320. By limiting the movement of plunger 322, lost motion component 300 is prevented from applying excessive compressive force to any hydraulic lash adjuster components in the valve train, thereby preventing collapse of the hydraulic lash adjuster.

[0041] 3, the locking mechanism 310 includes a plunger 322 disposed within a housing bore 330 formed and extending from a first end of the housing 320 along a longitudinal axis of the lost motion component 300. An inner plunger 332 is slidably disposed within a longitudinal bore 334 formed within the plunger 322. An inner plunger spring 342 engages the inner plunger 322. 332and plunger cap 343, which tends to bias the inner plunger out of bore 334. A locking element in the form of a wedge 336 is provided, which is configured to engage an annular external recess 338 formed in the surface defining housing bore 330. The illustrated embodiment is of locking mechanism 310 in a normally locked state, i.e., in the absence of hydraulic control applied to inner plunger 332 via lost motion hydraulic passage 340, inner plunger spring 342 biases inner plunger 322 into a predetermined position such that wedge 336 extends radially from an opening formed in plunger 332, thereby engaging external recess 338 and effectively locking plunger 320 in position relative to housing 320.

[0042] In this locked state, any valve-actuating motion (whether primary or secondary) applied to either end of lost motion component 300 is transmitted by lost motion component 300. Note that even in the locked state as shown in FIG. 3 , the longitudinal extent of outer recess 338 is greater than the thickness of wedge 336 so that a small amount of movement is permitted between plunger 322 and housing 320. Such additional space provided by outer recess 338 facilitates locking / unlocking of locking mechanism 310 when lost motion component 300 is removed. As shown in FIG. 3 , this additional space is occupied, for example, when valve-actuating motion is applied to lost motion component 300, thereby overcoming any outward bias applied to plunger 322 by plunger spring 324.

[0043] The bias applied by plunger spring 324 can be selected to further ensure that adjacent valve train components 352, 354 (or such additional upstream or downstream valve train components in the system, not shown) are biased into continuous contact with the respective endpoints of the valve train, i.e., the source of valve actuation motion and the engine valve. For example, as described in more detail below, the input and output rockers are provided in a rocker assembly in series with the lost motion component. In this case, the lost motion component's plunger spring 324 can apply a biasing force to the input and output rockers to ensure that the input rocker is biased into contact with the source of valve actuation motion and / or the output rocker is biased toward the respective engine valve, thereby sufficiently loading any hydraulic lash adjuster components to prevent its overextension.

[0044] Referring again to Figure 3, the inside PlungerSupplying hydraulic fluid sufficiently pressurized to overcome the bias of spring 342 to the input receiving end (lowermost surface as shown in FIG. 3 ) of inner plunger 332 via lost motion hydraulic passage 340 causes inner plunger 332 to translate within bore 334, causing wedge 336 to retract and disengage from outer recess 338, thereby effectively unlocking plunger 322 from housing 320 and allowing plunger 322 to slide freely within its bore 330 under the bias, in this case provided by plunger spring 324. In this unlocked state, any valve actuation motion applied to lost motion component 300 will cause plunger 322 to reciprocate within its bore 330. Thus, assuming the travel of plunger 322 within bore 330 is greater than the maximum range of any applied valve actuation motion (i.e., plunger 322 cannot bottom out within its bore 330), such valve actuation motion is not transmitted by lost motion component 300 and is effectively lost. Alternatively, the movement of plunger 322 within bore 330 may be configured so that plunger 322 "bottoms out" or contacts the closed end of bore 330 to provide a "fail-safe" valve lift whenever locking mechanism 310 fails.

[0045] 3 illustrates a particular embodiment and configuration of lost motion component 300, it should be understood that other configurations may be utilized as well, and the disclosure is not limited in this respect. For example, as previously discussed, the illustrated lost motion component 300 is a normally locked lost motion component. However, those skilled in the art will appreciate that a normally unlocked type of lost motion component may be used as well.

[0046] FIG. 3A shows an example of a normally unlocked lost motion component 300′. Elements having the same reference numbers in FIGS. 3 and 3A are substantially similar in structure and function, while reference numbers including a prime symbol (′) in FIG. 3A refer to elements characterized by different structure and / or function relative to their counterparts shown in FIG. 3, as explained below. In the embodiment shown in FIG. 3A, the lost motion component 300′ again includes a housing 320 having a longitudinal bore 330 formed therein and a plunger 322′ slidably disposed within the bore 330. Similarly, the inner plunger 332′ is disposed within a bore 334′ formed in the plunger 322′ and is biased out of the bore 334′ by an inner plunger spring 342 disposed between the inner plunger 332′ and a plunger cap 343.

[0047] 3 , the inner plunger 332′ is configured essentially the opposite way around, such that, in the absence of hydraulic control applied to the inner plunger 332′, the inner plunger spring 342 biases the inner plunger 332′ into position such that the wedge 336 does not extend radially from the opening formed in the plunger 320 and therefore does not engage the outer annular recess 338′, thereby effectively unlocking the plunger 322′ from the housing 320 and allowing the plunger 322′ to slide freely within its bore 330 under the bias provided by the plunger spring 324. In this unlocked state, any valve actuation motion applied to the lost motion component 300 causes the plunger 322′ to reciprocate within its bore 330. In the illustrated embodiment, the plunger 322′ is configured such that movement of the plunger 322′ within its bore 330 allows the plunger 322′ to “bottom out,” i.e., in this case, contact between the plunger cap 343 and the closed end of the bore 330. In this manner, the lost motion component 300′ can prevent overextension of any hydraulic lash adjuster located in the same valve train as the lost motion component 300′. Additionally, such travel limiting of the plunger 322′ allows for the application of “fail-safe” auxiliary valve actuation motion, such as high-lift braking gas recirculation (BGR) motion, in the event of failure of the locking mechanism 310. Again, a stroke limit may be provided within the lost motion component 300′ to prevent overextension of the housing 320 and plunger 322′ away from each other, which could otherwise result in collapse of the hydraulic lash adjuster. For example, as shown in FIG. 3A, plunger cap 343 may be configured to include a radially extending lip or flange 333 configured to engage a shoulder 331 formed in bore 330, thereby preventing overextension of plunger 322′ from bore 330.

[0048] Meanwhile, supply of hydraulic fluid to the input receiving end (bottom surface shown in FIG. 3A ) of inner plunger 332′ that is sufficiently pressurized to overcome the bias of inner piston spring 342 causes inner plunger 332′ to translate within bore 334, forcing wedge 336 to extend and engage outer recess 338′, thereby effectively locking plunger 322′ relative to housing 320. In this locked state, valving motion applied to lost motion component 300′ causes plunger 322′ to engage housing 320, thereby transmitting such valving motion.

[0049] A further feature of the housing 320 is that the annular outer recess 338' has a longitudinal extent such that the plunger 322' can slide within its bore 330 even when the lost motion component 300' is in its locked / motion transmitting state. As explained in more detail below, this configuration of the outer recess 338' accommodates a separation between the first input rocker 112 and the first output rocker 116 during an operating state in which the first output rocker 116 is controlled by the second rocker 146 / second output rocker 246 and the intervening one-way couplings 170, 270.

[0050] 4-6, a first implementation of the valve actuation system according to the first embodiment of FIG. 1 is shown. In particular, the illustrated embodiment includes a first rocker assembly 402 and a second rocker assembly 404. The first rocker assembly 402 comprises a first input rocker 406, a first output rocker 408, and a lost motion component 410. The first input rocker 406 comprises a roller bearing 407 at a motion-receiving end thereof that is configured to receive valve actuation motion from a first valve actuation motion source, e.g., a cam disposed on an overhead camshaft (not shown). The first input rocker 406 is operably connected at its motion-imparting end to an input end of the first lost motion component 410. The first lost motion component 410, in turn, is operably connected at its output end to a motion-receiving end of the first output rocker 408. In one embodiment, the first input rocker 406 may include one or more hydraulic passages (not shown) configured to receive hydraulic fluid, for example from a rocker shaft (not shown), and route such hydraulic fluid to the first lost motion component 410 (thereby controlling its operation as described above with respect to FIG. 3 ).

[0051] The first output rocker 408, in this embodiment, includes a pair of lateral arms 412, 414 defining a central opening 416 therebetween that is configured to receive the first input rocker 406, thereby surrounding or enclosing the first input rocker 406 between the lateral arms 412, 414. The first output rocker 408 also includes a hydraulic lash adjuster 420, in this embodiment, configured to be operably connected to a first engine valve (not shown). The first output rocker 408 also includes one or more internal hydraulic passages (not shown) configured to receive hydraulic fluid, for example from a rocker shaft (not shown), and route such hydraulic fluid to the hydraulic lash adjuster 420 in accordance with known techniques.

[0052] As best shown in FIG. 4, the first output rocker 408 includes rocker shaft bores 418 formed in both of the lateral arms 412, 414 configured to receive a rocker shaft. Additionally, although not shown in FIGS. 4-6, the first input rocker 406 also includes a rocker shaft bore configured to receive a rocker shaft. As configured in this manner, both the first input rocker 406 and the first output rocker 408 can also reciprocate about the rocker shafts in response to valve-actuated motion applied to the first input rocker 406 (and to the output rocker 408 via the first lost motion component 410) or, as described in more detail below, in response to valve-actuated motion applied to the first output rocker 408 via the second rocker assembly 404.

[0053] It should be noted that from the perspective of the first source of valve actuation motion (applying valve actuation motion to the first input rocker 406) and the first engine valve (receiving valve actuation motion from the first output rocker 408), the first rocker assembly 402 operates like a Type II or end-pivot rocker arm, similar to so-called finger followers known in the art. However, to achieve such operation, the first rocker assembly 402, along with the first lost motion assembly 410, operates like two Type III or center-pivot rocker arms (the first input rocker 406 and the first output rocker 408 That is, first rocker assembly 402 can be considered a quasi-Type II rocker or a composite Type II rocker based on a combination of constituent Type III rockers.

[0054] The second rocker assembly 404, in this embodiment, includes a second rocker 422. As best shown in FIGS. 5 and 6, the second rocker 422, in this embodiment, is a shaft-mounted end pivot rocker or Type II rocker with a rocker shaft bore 424 configured to receive a rocker shaft. As shown, the second rocker assembly 404 resides adjacent to the first rocker assembly 402; more specifically, the second rocker 422 is disposed on the rocker shaft adjacent to the first output rocker 408. The second rocker 422 also includes a roller bearing 423 configured to receive valve actuation motion from a second source of valve actuation motion (e.g., a cam disposed on an overhead camshaft). The second rocker 422 also includes a hydraulic lash adjuster 426, in this embodiment, configured to be operably connected to a second engine valve (not shown). Similar to first output rocker 408, second rocker 422 also includes one or more internal hydraulic passages (not shown) configured to receive hydraulic fluid, for example from a rocker shaft, and route such hydraulic fluid to hydraulic lash adjuster 426 in accordance with known techniques. So configured, second rocker 422 is capable of reciprocating about the rocker shaft in response to valve actuation motion applied by a second source of valve actuation motion and of transmitting such valve actuation motion to a second engine valve.

[0055] 4 and 5, a one-way coupling 430 is provided between the second rocker arm 422 and the first output rocker 408. In this embodiment, the one-way coupling 430 is formed by the combination of a coupling arm 432 and a coupling contact surface 434 located at the motion-imparting ends of the second rocker 422 and the first output rocker 408, respectively. The coupling arm 432 is integrally formed on the second rocker 422 and extends toward the first output rocker 408. The upward-facing coupling contact surface 434 contacts the first output rocker 408. 408and is aligned to establish contact (but not lock or fasten) with the downwardly facing surface of the coupling arm 432. In this manner, valve actuation motion applied to the second rocker 422 is transmitted to the first output rocker 408, but valve actuation motion applied to the first output rocker 408 via the first input rocker 406 and first lost motion component 410 is not transmitted to the second rocker 422. In the illustrated embodiment, the components of the one-way coupling 430 are located at the motion-transmitting ends of the second rocker 422 and first output rocker 408, although it should be understood that the one-way coupling 430 may be located at various positions between the respective rockers. Furthermore, while the contact surfaces provided by the coupling arm 432 and the coupling contact surface 434 are shown as fixed surfaces, it should be understood that such surfaces may be selectable, such as in the case of an adjustable lash screw or the like. It will further be appreciated that the one-way coupling 430 may be configured using two coupling arms extending toward each other with overlapping contact surfaces, as may be necessary if the first rocker assembly 402 and the second rocker assembly 404 are not positioned directly adjacent to each other.

[0056] 7 and 8, a second implementation of the valve actuation system according to the second embodiment of FIG. 2 is shown. Based on FIG. 2, the implementation shown in FIGS. 7 and 8 includes a first rocker assembly 402 and an adjacent second rocker assembly 704. The first rocker assembly 402 shown in FIGS. 7 and 8 is essentially identical in function and structure to the first rocker assembly 402 shown in FIGS. 4-6, as indicated by like reference numerals. However, based on the embodiment of FIG. 2, the second rocker assembly 704 is more complex than the second rocker assembly 404 shown in FIGS. 4-6. In this case, the second rocker assembly 704 includes a second input rocker 706, a second output rocker 708, and a second lost motion component 710. Second input rocker 706 comprises a roller bearing 707 configured at a motion-receiving end of second input rocker 706 to receive valve-actuating motion from a second valve-actuating motion source, for example, a cam disposed on an overhead camshaft (not shown). Second input rocker 706 is operatively connected at its motion-imparting end to an input end of second lost motion component 710. Second lost motion component 710 is, in turn, operatively connected at its output end to a motion-receiving end of second output rocker 708. In one embodiment, second input rocker 706 may include one or more hydraulic passages (not shown) configured to receive hydraulic fluid, for example, from a rocker shaft (not shown), and route such hydraulic fluid to second lost motion component 710 (thereby controlling its operation as described above with respect to FIG. 3 ). The second output rocker 708 is substantially identical to the first output rocker 408, comprising a pair of lateral arms 712, 714 defining a central opening 716 therebetween, the central opening 716 being configured to receive the second input rocker 706, thereby surrounding or enclosing the second input rocker 706 between the lateral arms 712, 714.

[0057] 4-6, rather than hydraulic lash adjusters, the first output rocker 408 and the second output rocker 708 each include a lash screw and swivel (or e-foot) assembly 720, 740 located at the motion-imparting ends of the first output rocker 408 and the second output rocker 708. Nevertheless, it will be understood that a respective hydraulic lash adjuster may be used in place of one or both of the lash screw assembly 720 and the swivel assembly 740, provided that either or both of the first output rocker 408 and the second output rocker 708 are configured to include the hydraulic passages necessary to operate the hydraulic lash adjuster.

[0058] As best shown in FIG. 8 , the second output rocker 708 includes a rocker shaft bore 718 formed in both of the lateral arms 712, 714 configured to receive a rocker shaft. Additionally, although not shown in FIGS. 7 and 8 , the second input rocker 706 also includes a rocker shaft bore configured to receive a rocker shaft. So configured, both the first input rocker 706 and the first output rocker 708 can also reciprocate about the rocker shaft in response to valve-actuated motion applied to the first input rocker 406 (and to the output rocker 408 via the first lost motion component 410) or to the first output rocker 408 via the second rocker assembly 704 and one-way coupling 730.

[0059] Similar to the embodiment shown in Figures 4-6, second rocker assembly 704 resides adjacent to first rocker assembly 402, and more specifically, second output rocker 708 is disposed on the rocker shaft adjacent to first output rocker 408. Second input rocker 706 also includes roller bearing 707 configured to receive valve-acting motion from a second source of valve-acting motion (e.g., a cam disposed on an overhead camshaft). So configured, second input rocker 706 and second output rocker 708 (together with second lost motion component 710) can reciprocate about the rocker shaft in response to valve-acting motion imparted to second input rocker 706 by the second source of valve-acting motion.

[0060] As best shown in FIG. 7 , a one-way coupling 730 is provided between the second output rocker 708 and the first output rocker 408. In this embodiment, the one-way coupling 730 is formed by the combination of a coupling arm 732 located at the motion-imparting end of the second output rocker 708 and the first output rocker 408, respectively, and the coupling contact surface 434 described above. In this case, the coupling arm 732 is integrally formed with the second output rocker 708 and extends toward the first output rocker 408. Again, the upwardly facing coupling contact surface 434 is integral with the first output rocker 434 and is aligned to establish contact (but not lock or clamp) with the downwardly facing surface of the coupling arm 732. In this way, valve actuation motion applied to the second output rocker 708 (via the second input rocker 706 and the second lost motion component 710) is transmitted to the first output rocker 408, but valve actuation motion applied to the first output rocker 408 via the first input rocker 406 and the first lost motion component 410 is not transmitted to the second output rocker 732. Again, the variations on the one-way coupling 430 shown in Figures 4-6 can be similarly applied to the one-way coupling 730 shown in Figures 7 and 8.

[0061] As will be appreciated by those skilled in the art, the implementations of rocker assemblies 402, 404, 704 in Figures 4-8 effectively provide end pivoting or Type II motion for each rocker assembly. As known in the art, a Type II rocker utilizes a rocker arm that pivots about one of its ends and imparts valve-acting motion at its other end, with an application or valve-actuating force being applied to the rocker arm at a point midway between the pivot end and the load-application end. Thus, in the implementations of Figures 4-8, each of rocker assemblies 402, 404, 704 behaves like a Type II in that the assembly rotates or pivots about a rocker shaft and imparts valve-actuating motion at the opposite end of the assembly, and the assembly receives at least some valve-actuating motion from a valve-actuating motion source applied between its pivot end and motion-application end.

[0062] 9-11, a second implementation of the valve actuation system according to the second embodiment of FIG. 2 is shown. With reference to FIG. 2, the implementation shown in FIGS. 9-11 includes a first rocker assembly 902 and an adjacent second rocker assembly 904. Functionally, the implementation shown in FIGS. 9-11 is substantially identical to the implementation shown in FIGS. 7 and 8 in that the first rocker assembly 902 includes a first input rocker 906, a first output rocker 908, and an intervening first lost motion component 910 operably connected to the first input rocker 906 and the first output rocker 908, and the second rocker assembly 904 includes a second input rocker 912, a second output rocker 914, and an intervening second lost motion component 916 operably connected to the second input rocker 912 and the second output rocker 914. 10 and 11, each of the illustrated input rockers 906, 912 and output rockers 908, 914 includes a respective vertically extending boss 940, 942, 944, 946 configured to receive a respective end of the first lost motion component 910 and second lost motion component 916, as shown. In this case, a hydraulic fluid supply for controlling the operation of the respective lost motion components 910, 916 may be provided through suitable hydraulic passages (not shown) formed in either the input rockers 906, 912 and output rockers 908, 914 and their corresponding bosses 940, 942, 944, 946.

[0063] In this embodiment, all of the illustrated input rockers 906, 912 and output rockers 908, 914 are half rocker arms mounted on shafts. As best shown in FIGS. 9 and 10 , respectively, the second output rocker 914 and the first output rocker 908 each include a rocker shaft bore 924 that allows the respective output rocker 908, 914 to reciprocate about the rocker shaft. Although not shown in FIGS. 9 or 10 , each of the input rockers 906, 912 includes a similar rocker shaft bore that allows the respective input rocker 906, 912 to reciprocate about the rocker shaft. As best shown in FIG. 10 , each input rocker 906, 912 includes a roller bearing 907, 913, respectively, for receiving valve actuation motion from respective first and second sources of valve actuation motion (not shown), such as cams on a camshaft. Additionally, as best shown in Figure 9, each output rocker 908, 914 includes a lash adjustment screw and swivel assembly 930, 932, respectively, similar to the implementations shown in Figures 7 and 8. However, again, it is understood that either or both of the lash adjustment screw and swivel assemblies 930, 932 may be replaced with hydraulic lash adjusters, provided that the corresponding first output rocker 908 and / or second output rocker 914 includes one or more hydraulic passages configured to provide hydraulic fluid to such lash adjusters.

[0064] A feature of this implementation, as best shown in Figure 11 (in top view, the first lost motion component 910 and the second lost motion component 916 have been removed to better show the rockers 906, 908, 912, 914), is that the input rockers 906, 912 have a side-by-side mounting relationship with their corresponding output rockers 908, 914, unlike the implementations of Figures 7 and 8 in which the input rockers 406, 706 are nested within their corresponding output rockers 408, 708.

[0065] It should be noted that from the perspective of the source of valve-actuating motion (applying valve-actuating motion to first input rocker 906 and second input rocker 912) and the first and second engine valves (receiving valve-actuating motion from first output rocker 908 and second output rocker 914), first rocker assembly 902 and second rocker assembly 904 operate like Type 3 or center-pivot rocker arms, as known in the art. In this case, to achieve such operation, first rocker assembly 902 and second rocker assembly 904 rely on a combination of two Type 3 / center-pivot rocker arms along with corresponding first lost motion assembly 910 and second lost motion assembly 916, respectively. That is, first rocker assembly 902 and second rocker assembly 904 can be considered quasi-Type 3 rockers or composite Type 3 rockers based on a combination of constituent Type 3 rockers.

[0066] Additionally, a one-way coupling 930 is provided between the first rocker assembly 902 and the second rocker assembly 904. However, in this implementation, the one-way coupling 918 comprises a pair of coupling arms 920, 922. In this case, the first coupling arm 920 is integrally formed with the first output rocker 908 and extends toward the second output rocker 914, and the second coupling arm 922 is integrally formed with the second output rocker 914 and extends toward the first output rocker 908. The extension of the first coupling arm 920 and the second coupling arm 922 is such that the upward-facing contact surface of the first coupling arm 920 faces the downward-facing contact surface of the second coupling arm 922, which has overlapping contact surfaces, as best shown in FIG. 9 . So configured, first rocker assembly 902, second rocker assembly 904 and one-way coupling 918 operate essentially similarly to first rocker assembly 402, second rocker assembly 704 and one-way coupling 730 shown in Figures 7 and 8.

[0067] As will be appreciated by those skilled in the art, in contrast to the implementations shown with respect to Figures 4-8, the implementation of rocker assemblies 902, 904 in Figures 9-11 effectively provides a central pivoting or Type III motion for each rocker assembly. As known in the art, Type III rockers utilize rocker arms that pivot about a midpoint while accepting a force or valve actuation motion at one end and imparting such valve actuation motion at the other end. Thus, in the embodiment of Figures 9-11, each of rocker assemblies 902, 904 exhibits Type III-like behavior in that the assembly rotates or pivots about a rocker shaft while accepting at least some valve actuation motion at one end of the assembly and imparting such valve actuation motion at the opposite end of the assembly.

[0068] Figures 12-21 are cross-sectional views of a valve actuation system utilizing the lost motion component 300' of Figure 3A. In particular, Figures 12-21 illustrate examples of the implementations of Figures 4-6 or 7 and 8, although it is understood that the lost motion component 300' may be equally applied to the implementations shown in Figures 9-11. In the example shown in Figures 12-21, a first cam implementing a first source of valve actuation motion is configured to provide two compression-release engine braking valve actuations 1206, 1208 and a BGR valve actuation 1210, and a second cam implementing a second source of valve actuation motion is configured to provide a main exhaust valve actuation 1212, as known in the art.

[0069] Figure 12 shows a first input rocker 1202 and a first output rocker 1204, where the first input rocker 1202 includes a cam roller 1214 configured to receive valve actuation motion from a first valve actuation motion source. Although not shown in Figures 12-21, a second rocker / second output rocker and one-way coupling (as described above) are provided and configured to receive valve actuation motion from a second valve actuation motion source and to transmit such valve actuation to the first output rocker 1204. As further shown, a lost motion component 300' according to Figure 3A is disposed between and operatively connected to the first input rocker 1202 and the first output rocker 1204.

[0070] 12 shows the lost motion component 300′ in an unlocked state with both the first and second cams at base circle. In this state, the plunger spring 324 is free to bias the housing 320 and plunger 322′ away from each other, and in so doing, also biases the first input rocker 1202 into contact with the first cam and the first output rocker 1204 into contact with an engine valve (not shown).

[0071] 13-15 show the lost motion component 300' remaining in the unlocked state and the first cams respectively applying (i) the peak of the first compression-release valve actuation 1206 to the first input rocker 1202, (ii) the peak of the BGR valve actuation 1210 to the first input rocker 1202, and (iii) the peak of the second compression-release valve actuation 1208 to the first input rocker 1202. FIG. 14 also shows the partial application of the main exhaust valve actuation 1212 applied to the first output rocker 1204 (via a one-way coupling). In each of FIGS. 13-15, the applied valve actuation causes the plunger 322' to slide within its bore, resulting in compression (FIGS. 13 and 15) or expansion (FIG. 14) of the plunger spring 324 relative to its initial state as shown in FIG. 12. In this manner, as described above, the bias applied by the plunger spring 324 ensures continuous contact between the first rocker 1202 and the first cam, as well as continuous contact between the lost motion component 300′ and the first input rocker 1202 and the first output rocker 1204.

[0072] 16 illustrates a situation in which the lost motion component 300′ remains unlocked, the first cam partially applies the BGR valve actuation 1210 to the first input rocker 1202, and the second cam applies the peak of the main exhaust valve actuation 1212 (again via a one-way coupling) to the first output rocker 1204. As a result of this occurrence, the first output rocker 1204 is in a high-lift state and the first input rocker 1202 is in a relatively low-lift state. In this state, the plunger spring 324 is free to urge the housing 320 and plunger 322′ further away from each other, again urging the first input rocker 1202 into contact with the first cam and urging the first output rocker 1204 into contact with the engine valve (not shown). That is, the lost motion component 300' can expand to a sufficient extent under the bias provided by the plunger spring 324 to ensure continuous contact between the lost motion component 300' and the first input rocker 1202 and first output rocker 1204, as well as continuous contact between the first input rocker 1202 and the first cam.

[0073] Figure 17 shows a state substantially equivalent to that shown in Figure 12, except that the first lost motion component 300' remains in its locked / motion transmitting state. Despite this change in state of the lost motion component 300', the plunger spring 324 is again free to urge the housing 320 and plunger 322' away from each other, and in so doing also urge the first input rocker 1202 into contact with the first cam and the first output rocker 1204 into contact with the engine valve.

[0074] 18-21 show the state in which the lost motion component 300′ remains locked and the first cams respectively (i) apply the peak of the first compression-release valve actuation 1206 to the first input rocker 1202, (ii) apply the peak of the BGR valve actuation 1210 to the first input rocker 1202, (iii) apply the peak of the second compression-release valve actuation 1208 to the first input rocker 1202, and (iv) the first cam partially applies the BGR valve actuation 1210 to the first input rocker 1202 and the second cam applies the peak of the main exhaust valve actuation 1212 (again via a one-way coupling) to the first output rocker 1204. FIG. 19 further shows the partial application of the main exhaust valve actuation 1212 being applied to the first output rocker 1204 (via a one-way coupling). 18-21, applied valve actuation causes plunger 322' to engage housing 320 through the interaction of wedge 336 and the upper surface of annular outer recess 338'. As a result, various applied valve actuations are applied to the engine valves.

[0075] 17-21 , depending on the configuration of the first and second cams, the difference in lift applied to the first input rocker 1202 (via the first cam) and the first output rocker 1204 (via the one-way coupling) may cause the plunger 322′ and the housing 330 to tend to separate from each other, even though the lost motion component 300′ is in a locked / motion-transmitting state. In these situations, the longer longitudinal length of the annular outer recess 338′ still allows expansion of the lost motion component 300′ despite the locked state, thereby ensuring maintenance of the lost motion component 300′ between the first input rocker 1202 and the first output rocker 1204.

[0076] While various embodiments according to the present disclosure have been described in conjunction with specific implementations thereof, it is evident that many alternatives, modifications, and variations will be apparent to those skilled in the art. In various embodiments described herein, the input rocker and output rocker are shown as pivoting about rocker shafts. However, it is understood that the present disclosure need not be limited in this respect, and pivoting configurations other than about rocker shafts may equally be employed. For example, the input rocker and output rocker may each pivot about a different shaft. Furthermore, such shafts may be attached to other rocker arms or separate shaft mounts.

[0077] Accordingly, the preferred embodiments of the invention described herein are intended to be illustrative only, and not limiting, provided that variations thereof come within the scope of the appended claims and their equivalents.

Claims

1. 1. A system for actuating at least two engine valves associated with a cylinder of an internal combustion engine, comprising: a first rocker assembly operatively connected to a first source of valve actuation motion and to a first engine valve of the at least two engine valves, the first rocker assembly including a first lost motion component disposed in series with a first input rocker and a first output rocker, the first input rocker configured to receive a first valve actuation motion from the first source of valve actuation motion and the first output rocker configured to impart the first valve actuation motion to the first engine valve, the first lost motion component operable in a motion absorbing state to prevent transmission of the first valve actuation motion from the first input rocker to the first output rocker and in a motion transmitting state to transmit the first valve actuation motion from the first input rocker to the first output rocker; a second rocker assembly 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 assembly comprising at least one second rocker configured to receive second valve actuation motion from the second valve actuation motion source and to impart the second valve actuation motion to the second engine valve; a one-way coupling mechanism disposed between the first output rocker and the at least one second rocker such that the second valve actuation motion is transmitted from the at least one second rocker to the first output rocker and such that the first valve actuation motion is not transmitted from the first output rocker to the at least one second rocker.

2. The system of claim 1 , wherein the first output rocker comprises a hydraulic lash adjuster.

3. The system of claim 1 , wherein the at least one second rocker comprises a hydraulic lash adjuster.

4. The system of claim 1 , wherein the first rocker assembly is configured to operate as a Type II rocker.

5. The system of claim 1 , wherein the first rocker assembly is configured to operate as a Type III rocker.

6. The system of claim 1 , wherein the first input rocker and the first output rocker each comprise a half rocker attached to a shaft.

7. 7. The system of claim 6, wherein the first output rocker includes lateral arms defining a central opening, the central opening configured to receive the first input rocker between the lateral arms.

8. The system of claim 6 , wherein the first output rocker and the first input rocker are configured to be positioned adjacent to one another.

9. The system of claim 1 , wherein the at least one second rocker comprises a shaft-mounted Type II rocker.

10. 2. The system of claim 1, wherein the one-way coupling mechanism comprises a coupling arm forming a portion of the at least one second rocker and a coupling contact surface forming a portion of the first output rocker, the coupling arm and the coupling contact surface being configured to contact one another.

11. The system of claim 1 , wherein the first lost motion component includes a hydraulically controlled locking mechanism.

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

13. The system of claim 1 , wherein the first lost motion component is configured to provide a fail-safe lift event.

14. The at least one second locker comprises:

2. The system of claim 1, comprising: a second lost motion component disposed in series with a second input rocker and a second output rocker, the second input rocker configured to receive the second valve-actuating motion from the second valve-actuating motion source and the second output rocker configured to impart the second valve-actuating motion to the second engine valve, the second lost motion component operable in a motion-absorbing state to prevent transmission of the second valve-actuating motion from the second input rocker to the second output rocker and in a motion-transmitting state to transmit the second valve-actuating motion from the second input rocker to the second output rocker.

15. The system of claim 14 , wherein the second output rocker comprises a hydraulic lash adjuster.

16. 15. The system of claim 14, wherein the second rocker assembly is configured to operate as a Type II rocker.

17. 17. The system of claim 16, wherein the first rocker assembly is configured to operate as a Type II rocker.

18. 15. The system of claim 14, wherein the second rocker assembly is configured to operate as a Type III rocker.

19. 20. The system of claim 18, wherein the first rocker assembly is configured to operate as a Type III rocker.

20. The system of claim 14 , wherein the second input rocker and the second output rocker each comprise a half rocker attached to a shaft.

21. 21. The system of claim 20, wherein the second output rocker includes lateral arms defining a central opening, the central opening configured to receive the second input rocker between the lateral arms.

22. 21. The system of claim 20, wherein the second output rocker and the second input rocker are configured to be positioned adjacent to one another.

23. 15. The system of claim 14, wherein the one-way coupling mechanism comprises a coupling arm forming a portion of the second output rocker and a coupling contact surface forming a portion of the first output rocker, the coupling arm and the coupling contact surface configured to contact one another.

24. The system of claim 14 , wherein the second lost motion component includes a hydraulically controlled locking mechanism.

25. 15. The system of claim 14, wherein the second lost motion component includes a spring that biases the second input rocker toward the second source of valve actuation motion and biases the second output rocker toward the second engine valve.

26. The system of claim 14 , wherein the second lost motion component is configured to provide a fail-safe lift event.

Images