Bridgeless, single output, coupled hydraulic rocker arm

Abstract

A rocker arm for actuating at least two engine valves in an internal combustion engine comprises a unitary body configured to span at least two engine valves and a motion source interface supported by the body and configured to receive main valve actuations and auxiliary valve actuations from a motion source. The rocker arm further comprises a hydraulic control circuit supported by the body and configured to receive hydraulic fluid from a hydraulic fluid source, and a valve interface operatively supported by the body and operatively connected to the hydraulic control circuit, wherein the valve interface is configured and selectively operable via the hydraulic control circuit to convey the main valve actuations to the at least two engine valves and to convey the auxiliary valve actuations to at least a first engine valve of the at least two engine valves.

Description

BRIDGELESS, SINGLE OUTPUT, COUPLED HYDRAULIC ROCKER ARMFIELD

[0001] The present disclosure relates generally to valvetrain components for internal combustion engines, including rocker arms and auxiliary valve actuation components. The present disclosure also relates to coupled rocker arms that combine main valve actuation rocker and auxiliary valve actuation rocker features. The present disclosure also relates to dedicated rocker systems and lost motion rocker systems for implementing auxiliary valve actuation motions.BACKGROUND

[0002] In the context of providing auxiliary valve actuation motions to engine valves in an internal combustion engine, it is known to use, for any given cylinder, either a dedicated rocker arm in which a separate rocker arm dedicated to receiving and conveying auxiliary valve actuation motions is provided, or an integrated rocker arm in which a single rocker arm is used to receive and convey both main and auxiliary valve actuation motions. As used herein, the descriptor “main” refers to so-called main event valve actuation motions, i.e., valve motions used during positive power generation in which fuel is combusted in an engine cylinder to provide a net output of engine power, whereas the descriptor “auxiliary” refers to other valve actuation motions for purposes that are alternative to positive power generation (e.g., compression release braking, bleeder braking, cylinder decompression, cylinder deactivation, brake gas recirculation (BGR), etc.) or in addition to positive power generation (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] For example, valve actuation motions to achieve compression release (CR) engine braking are a well-known form of auxiliary valve actuations. Such engine braking may be implemented using a dedicated CR brake rocker arm, which is separate from a main exhaust rocker arm (i.e., a rocker arm for receiving and conveying main valve actuation motions). On the other hand, integrated rocker brake systems may combine a CR brake rocker arm and main exhaust rocker arm into a single unitary rocker arm, resulting in cost savings and a more compact form factor, which is advantageous in saving space in an engine overhead environment. A typical configuration for an integrated rocker brake is described in U.S. Patent No. 12,286,909.

[0004] In many internal combustion engines, the main and / or auxiliary motion sources may be provided by fixed profile cams, and more specifically by one or more fixed lobes that may be an integral part of each of the cams. Benefits such as increased performance, improved fuel economy, lower emissions, and better vehicle drivability may be obtained if the intake and / or exhaust valve timing and lift can be varied. The use of fixed profile cams, however, can make it difficult to adjust the timings and / or amounts of engine valve lift to optimize them for various engine operating conditions.

[0005] Thus, techniques that overcome the above-noted shortcomings would represent a welcome advancement in the art.SUMMARY

[0006] The instant disclosure describes rocker arm for actuating at least two engine valves in an internal combustion engine. In particular, the rocker arm comprises a unitary body configured to span the at least two engine valves and a motion source interface supported by the body andconfigured to receive main valve actuations and auxiliary valve actuations from a motion source. The rocker arm further comprises a hydraulic control circuit supported by the body and configured to receive hydraulic fluid from a hydraulic fluid source, and a valve interface operatively supported by the body and operatively connected to the hydraulic control circuit, wherein the valve interface is configured and selectively operable via the hydraulic control circuit to convey the main valve actuations to the at least two engine valves and to convey the auxiliary valve actuations to at least a first engine valve of the at least two engine valves.

[0007] In an embodiment, wherein the motion source comprises a first cam, the motion source interface comprises a first roller configured to align with the first cam. Additionally, in an embodiment, wherein the motion source comprises a second cam, the motion source interface comprises a second roller configured to align with the second cam.

[0008] In an embodiment, the valve interface comprises a hydraulically controlled lost motion component aligned with the first engine valve. Further this embodiment, the valve interface may comprise a stroke limited contact member aligned with a second engine valve of the at least two engine valves. A spring configured to bias the stroke limited contact member into contact with the second valve and to bias the motion source interface toward the motion source may be provided. In an embodiment, the stroke limited contact member is configured to cause a reset of the hydraulically controlled lost motion component based on position of the rocker arm. In an embodiment, the rocker arm may comprise a reset component in hydraulic communication with the hydraulically controlled lost motion component and configured to cause a reset of the hydraulically controlled lost motion component based on position of the rocker arm.

[0009] In an embodiment, the hydraulic control circuit may comprise a control valve configured to receive the hydraulic fluid from the hydraulic fluid source and to provide the hydraulic fluid to a hydraulically controlled lost motion component aligned with the first engine valve.

[0010] In an embodiment, a spring may be operatively connected to the body and configured to bias the motion source interface toward the motion source.

[0011] In an embodiment, a valve actuation system comprises the motion source providing the main valve actuations and auxiliary valve actuations and the rocker arm described herein. In this embodiment, the motion source may comprise a first cam and the motion source interface may comprise a first roller configured to align with the first cam. In an embodiment, the first cam may comprise a main lobe configured to provide the main valve actuations and at least one auxiliary lobe configured to provide the auxiliary valve actuations. In another embodiment, the motion source comprises a second cam and the motion source interface comprises a second roller configured to align with the second cam. Further this embodiment, the first cam comprises a main lobe configured to provide the main valve actuations and the second cam comprises at least one auxiliary lobe configured to provide the auxiliary valve actuations.BRIEF DESCRIPTION OF THE DRAWINGS

[0012] The foregoing and other features and advantages will be discussed in detail in the following non-limiting description of specific embodiments in connection with the accompanying drawings, in which:

[0013] FIG. 1 is a schematic block diagram of a valve actuation system comprising a first embodiment of a rocker arm in accordance with the instant disclosure;

[0014] FIGs. 2 and 3 are illustrations of examples of first and second cams that may be used in conjunction with the embodiment illustrated in FIG. 1;

[0015] FIGs. 4-6 are respective perspective and cross-sectional views of a rocker arm in accordance with the embodiment illustrated in FIG. 1 ;

[0016] FIGs. 7 and 8 are cross-sectional illustrations of an alternative stroke limited contact member in accordance with prior art techniques that may be incorporated into the various embodiments described herein;

[0017] FIG. 9 is a cross-sectional illustration of a reset component in accordance with prior art techniques that may be incorporated into the various embodiments described herein;

[0018] FIG. 10 is a schematic block diagram of a valve actuation system comprising a second embodiment of a rocker arm in accordance with the instant disclosure;

[0019] FIG. 11 is an illustration of an example of a cam that may be used in conjunction with the embodiment illustrated in FIG. 10; and

[0020] FIGs. 12-15 are respective perspective and cross-sectional views of a rocker arm in accordance with the embodiment illustrated in FIG. 10.DETAILED DESCRIPTION OF THE PRESENT EMBODIMENTS

[0021] As used herein, phrases substantially similar to “at least one of A, B or C” are intended to be interpreted in the disjunctive, i.e., to require A or B or C or any combination thereof unless stated or implied by context otherwise. Further, phrases substantially similar to “at least one of A, B and C” are intended to be interpreted in the conjunctive, i.e., to require at least one of A, at leastone of B and at least one of C unless stated or implied by context otherwise. Further still, the term “substantially” or similar words requiring subjective comparison are intended to mean “within manufacturing tolerances” unless stated or implied by context otherwise.

[0022] As used herein, the phrase “operatively connected” refers to at least a functional relationship between two elements and may encompass configurations in which the two elements are directed connected to each other, i.e., without any intervening elements, or indirectly connected to each other, i.e., with intervening elements.

[0023] As used herein, the phrase “fluid communication” refers to a configuration between two or more elements in which fluid is able to flow in at least one direction between such elements.

[0024] Referring now to FIG. 1, a schematic illustration of a valve actuation system 102 for use in an internal combustion engine 100 is presented. In particular, the system 102 comprises a first embodiment of a rocker arm 104 in accordance with the instant disclosure. As shown, the rocker arm 104 comprises a unitary body 106 configured to span two or more engine valves so as to be able to actuate such valves according to valve actuation motions received from a motion source, as further described below. The body 106 comprises a motion source interface 108, a valve interface 114 and a hydraulic control circuit 120.

[0025] The motion source interface 108 is configured to receive valve actuation motions from a valve actuation motion source 124, whereas the valve interface 114 is configured to convey valve actuation motions, from the motion source interface 108 via the body 106, to engine valves 132, 134. In the illustrated example, two engine valves 132, 134 are depicted. However, it isappreciated that the teachings of the instant disclosure may be applied to more than two engine valves provided that such engines valves are spanned by the body 106 of the rocker arm 104.

[0026] The system 102 is an example of a dedicated valve actuation system in that the motion source comprises two cams, a first cam 126 for providing main valve actuations and a second cam 128 for providing auxiliary valve actuations, i.e., second cam 128 is dedicated to the provision of at least one or more auxiliary valve actuation. Given this, the motion source interface 108 correspondingly comprises a first follower 110 and a second follower 112 respectively configured to receive valve actuation motions from, i.e., are aligned with, the first cam 126 and the second cam 128. Examples of such first and second cams 126, 128 are respectively illustrated in FIGs. 2 and 3. In FIG. 2, a cam 200 comprises a single main lobe 202, the surface of which is configured to provide main valve actuations to the first follower 110. A base circle 204 is illustrated and corresponds to a surface level at which the cam 200 provides no valve actuation motions to the corresponding first follower 110. On the other hand, FIG. 3 illustrates an example of a cam 300 comprising two auxiliary lobes 302, 304, which may provide by way of non-limiting example, brake gas recirculation (BGR) and compression release (CR) valve actuations to the second follower 112. FIG. 3 also illustrates a base circle 306 having the same diameter as the base circle 204 shown in FIG. 2. From this, it is evident that the auxiliary lobes 302, 304 provide peak lifts that are less than a peak lift of the main lobe 202. Further, as illustrated, the respective angular distributions of the main and auxiliary lobes 202, 302, 304 are such that the respective lobes do not overlap with each other, i.e., there are regions of zero lift in between each of the lobes 202, 302, 304. However, this is not a requirement and it is possible for various ones of the lobes to overlap with each other, e.g., an auxiliary lobe may overlap with a main lobe in the case whereearly exhaust valve opening (EEVO) operation is desired. Regardless, in this manner, the first and second cams 126, 128 are able to provide both main and auxiliary valve actuations to the body 106 of the rocker arm 104, which motions may be selectively conveyed to the engine valves 132, 134 as described in further detail below.

[0027] The valve interface 114 comprises a lost motion component 116 aligned with the first engine valve 132 and a stroke limited contact member 118 aligned with the second engine valve 134. In an embodiment, both the lost motion component 116 and the stroke limited contact member 118 are configured to be capable of losing any auxiliary valve actuation motions received from the second cam 128 by the second follower 112 and conveyed by the body 106 to the valve interface 114. At the same time, both the lost motion component 116 and the stroke limited contact member 118 are stroke limited so as to always convey at least a portion of the main valve actuations applied thereto, i.e., specifically, that portion of such main valve actuations that exceeds the peak lift of the auxiliary valve actuations (and stroke length of the lost motion component 116 and stroke limited contact member 118). On the other hand, the lost motion component 116 may be selectively controlled, as described in further detail below, to assume a rigid / locked / extended state in which the lost motion component 116 does not lose the auxiliary valve actuations applied thereto, but instead conveys such motions, in addition to the main valve actuations, to the first engine valve. During this state of conveying auxiliary valve actuations to the first engine valve 132, the stroke limited contact member 118 continues to operate as before by losing all auxiliary valve actuations while conveying main valve actuations. In this manner, despite the use of the unitary body 106, the rocker arm of FIG. 1 is capable of selectively conveying only the main valve actuations to both the first and second engine valves 132, 134, or conveying the main valveactuations to both the first and second engine valves 132, 134 as well as the auxiliary valve actuations to the first engine valve 132 but not the second engine valve 134.

[0028] In an embodiment, the lost motion component 116 is hydraulically controlled between a compliant / unlocked / retracted state (i.e., capable of losing auxiliary valve actuations) and the above-described rigid / locked / extended state by a hydraulic control circuit 120 supported by the body 106 of the rocker arm 104. The control circuit 120 is configured, via hydraulic passage in the body 106, to receive hydraulic fluid from a hydraulic fluid source 130 and provide such fluid to the lost motion component 116. For example, in accordance with well-known techniques, the hydraulic fluid source 130 may comprise an oil pump and / or pressurized oil reservoir in fluid communication with the rocker arm 104 via hydraulic passages provided in a rocker shaft and selectively applied to the rocker arm 104 under the control of an intervening solenoid (not shown). As further depicted, the control circuit may comprise a control valve 122 as known in the art, i.e., a checked valve configured to establish a locked volume of hydraulic fluid between the control valve 122 and the lost motion component 116 when hydraulic fluid is provided by the hydraulic fluid source 130, or to allow such locked volume of hydraulic fluid to vent (via a vent passage, V) when provision of hydraulic fluid to the control valve 122 is discontinued.

[0029] As described above, the rocker arm 104 is configured to be non-resetting in the sense that once switched to its rigid / locked / extended state, the lost motion component 116 will only “reset” to its compliant / unlocked / retracted state under control of the control valve 122, i.e., no such reset will occur through operation of any other component of the rocker arm 104. However, there are situations where it may be desirable to have resetting operation additionally controlled by othercomponents of the rocker arm 104, particularly, for example, during individual cycles of the respective cams 126, 128 based on position of the rocker arm 104.

[0030] For example, in a first resetting embodiment illustrated by dashed and dotted lines in FIG. 1, the lost motion component 116 may be in fluid communication with a reset component 138 that is configured to vent (via vent passage, V) any locked volume of fluid maintaining the lost motion component 116 is its rigid / locked / extended state based on position of the rocker arm 104. An example of this is illustrated in FIG. 9, which is a reproduction of FIG. 5 taken from U.S. Patent No. 11,149,599 and illustrates a rocker arm 902 having a lost motion component in the form of hydraulic actuator piston 904. In this example, a simple, static check valve 906 is used to establish a locked volume of hydraulic fluid in an actuator piston bore 908 and fluid passage 910, thereby causing the actuator piston 904 to maintain a rigid / locked / extended state. As further shown, a poppet-type valve 912 is provided in the rocker arm in fluid communication with the hydraulic passage 904 and actuator piston bore 908. A spring 914 is provided to bias the poppet valve 912 into a closed position as shown. As the rocker arm 902 rotates as commanded by a cam 916, a portion of the poppet valve 912 extending out of the rocker arm 902 will establish contact with a fixed surface 918 thereby causing the poppet valve 912 to open. A bore 920 in which the poppet valve 912 resides is configured such that, when the poppet valve 912 is forced open by the fixed surface 918, pressurized fluid in the hydraulic passage 904 and actuator piston bore 908 is allowed to rapidly vent. In turn, this effectuates a reset of the actuator piston 904 to its compliant / unlocked / retracted state thereby permitting the rocker arm 902 to lose at least a portion of any valve actuation motions applied thereto. Following the resetting operation and closing of the poppet valve 912, continued application of hydraulic fluid to the actuator piston bore 908permits the actuator piston 904 to once again assume its rigid / locked / extended state before another cycle of valve actuation motions is applied.

[0031] As another example of another resetting embodiment, FIG. 1 also illustrates, using dashed lines, a second, alternative resetting embodiment. In this embodiment, a reset component 136 is incorporated into the stroke limited contact member 118 and an additional hydraulic passage 140 is provided to establish fluid communication between the lost motion component 116 and the reset component 136 provided in the stroke limited contact member 118. In this case, the locked volume of hydraulic fluid maintaining the lost motion component in its rigid / locked / extended state extends to the additional hydraulic passage 140. As described in connection with an example depicted in FIGs. 4-6 and described below, rotation of the rocker arm 104 subsequently controls the stroke limited contact member 118 to eventually permit the locked volume of fluid in the additional hydraulic passage to vent through the resent component 136 (via vent passage, V) thereby resetting the lost motion component 116. Once again, continued application of hydraulic fluid to the lost motion component 116 via the control valve 122 will cause the lost motion component 116 to reassume its rigid / locked / extended state before another cycle of valve actuation motions is applied.

[0032] Referring now to FIGs. 4-6, an example of a rocker arm 400 in accordance with the first embodiment of FIG. 1 (when configured for resetting operation) is illustrated. As shown, the rocker arm 400 comprises a unitary body 402 configured to span, in this case, two engine valves and rotate about a rocker shaft (not shown) received in a rocker shaft bore 403. The rocker arm 400 further comprises a motion source interface 404 comprising two rollers 406, 408 configured to receive valve actuation motions from respective first and second cams, as described above. Both of the rollers 406, 408 reside on a roller shaft 414 disposed in a roller shaft bore 415 formed in thebody 402. To minimize profile of the rocker arm 400, each of the rollers 406, 408 is disposed in respective openings 410, 412 formed in the body 402, though this is not a requirement. Further still, and with additional reference to FIG. 5, the rocker arm 400 comprises a valve interface 416 that includes a lost motion component boss 418 having an actuator piston assembly 422 disposed in an actuator piston bore 504 formed therein, a contact member boss 420 having a contact member assembly 516 disposed in a contact member bore 508 formed therein, and a control valve boss 440 having a control valve 442 disposed in a control valve bore 520 formed therein.

[0033] As shown in the cross-sectional view shown in FIG. 5 (taken along section line 5-5 in FIG. 4), the unitary body 402 comprises a first hydraulic passage 510 that extends from the control valve bore 520 to the actuator piston bore 504, and a second hydraulic passage 512 that extends from the actuator piston bore 504 to the contact member bore 508. As described above, the control valve 442 operates such that, when hydraulic fluid is provided to the control valve 442, the control valve 442 in turn provides hydraulic fluid to the actuator piston bore 504, the second hydraulic passage 512 and the contact member bore 508 via the first hydraulic passage 510. As known in the art, when hydraulic fluid pressure on either side of a check valve disposed in the control valve 442 equalizes, the check valve is permitted to close, thereby locking the hydraulic fluid in the first hydraulic passage 510, the actuator piston bore 504, the second hydraulic passage 512 and a first bore 614 forming a part of the contact member assembly 516, as described below. This, in turn causes an actuator piston 502 of the actuator piston assembly 422 to assume its rigid / locked / extended state. If hydraulic fluid supplied to the control valve 442 is discontinued, and as again known in the art, the control valve 442 indexes so as to uncheck the locked volumeof hydraulic fluid, which is then permitted (in the illustrated example) to vent through the control valve 442 and the control valve bore 520.

[0034] In an embodiment, the actuator piston assembly 422 and contact member assembly 516 are substantially similar to corresponding assemblies disclosed in FIGs. 3-10 of U.S. Patent No. 12,286,909. As best shown in instant FIG. 6, the actuator piston assembly 422 is disposed in the actuator piston bore 504 formed in the downwardly open actuator piston boss 418 (as depicted in FIG. 6). The actuator piston assembly 422 comprises an actuator lash adjustment screw 602 that may be secured in place using a lash adjustment bolt 604, as known in the art. The actuator piston 502 is slidably disposed in the actuator piston bore 504 with sufficiently tight tolerance so as to retain high pressure fluid in the actuator piston bore 504. A swivel or “e-foot” 610 is movably attached to a spherical end of the actuator piston 502 and is configured to contact a first engine valve (not shown). A retainer 606 is attached to the actuator piston 502 through an open end thereof and is configured with a central opening 607 that permits the actuator lash adjustment screw 602 to be slidably received within the central opening 607. An actuator piston spring (not shown) is disposed between shoulders 608, 609 respectively formed on a lower surface of the retainer 606 and a distal end of the actuator lash adjustment screw 602 thereby tending to bias the retainer 606 and actuator piston 502 into the actuator piston bore 504. Travel of the actuator piston into the actuator piston bore 504 is limited when an upper surface of the actuator piston 502 abuts an upper wall of the actuator piston bore 504. On the other hand, travel of the actuator piston 502 out of the bore is limited by the distance between the respective shoulders 608, 609. In an embodiment, travel of the actuator piston 502 into the bore is configured to permit loss of any auxiliary valve actuations applied thereto while still ensuring solid contact between the actuatorpiston 502 and upper wall of the actuator piston bore 504 to ensure conveyance of at least a portion of any main valve actuations applied thereto.

[0035] As further shown in FIG. 6, the contact member assembly boss 516 is disposed in the contact member bore 508. The contact member assembly 516 comprises a contact member lash adjustment screw 506 that may be threadedly disposed in the contact member bore 508, and secured in place using a lash adjustment nut 612. The contact member lash adjustment screw 506 has an internal bore comprising a first or smaller diameter bore 614 and a second or larger diameter bore 616 both longitudinally formed therein, with the respective bores 614, 616 in fluid communication with each other through an intervening reduced- diameter opening or check seat configured to establish a fluidically-sealed relationship with a checking element or check ball 618. The check ball 618 is disposed in the first bore 614 and biased into contact with the check seat by a check spring 620 that reacts against a check spring retainer 621 deployed at an opposite end of the first bore 614.

[0036] The lash adjustment screw 506 comprises at least one radially extending bore (not shown) in fluid communication with the first bore 614 and an annular channel 622 formed on an external surface of the lash adjustment screw 506. The annular channel 622 is of sufficient longitudinal length so as to at least partially register with the second hydraulic passage 512 regardless of adjustments to the lash adjustment screw 506, thereby ensuring fluid communication between the second hydraulic passage 512 and the first bore 614.

[0037] A reset slider 624 is slidably disposed in a downward-facing open end of the second bore 616 and comprises a resetting pin 626 disposed on an upper surface of a second end of the reset slider 624 and aligned with the opening forming the check seat. As shown, the resetting pin 626is integrally formed in the reset slider 624, though this is not a requirement, as it could also, for example, comprise a separate member that is attached to the reset slider 624 (e.g., in threaded fashion). At a first or spherical end thereof, the reset slider 624 is also provided with a movable swivel or e-foot 628 that is configured to engage with a second engine valve (not shown). The reset slider 624 also comprises a diametrically and longitudinally extending notch 630, whereas the lash adjustment screw 506 comprises a transverse pin 632 diametrically spanning the second bore 616 and secured in openings (not shown) formed in sidewalls of the lash adjustment screw 506. The transverse pin 632 passes through the notch 630 thereby securing the reset slider 624 to the lash adjustment screw 506 while still permitting the reset slider 624 to slide within the second bore 616.

[0038] In the illustrated embodiment, the biasing element 634, preferably in the form of a compression spring, is disposed between shoulders respectively formed in the lash adjustment screw 506 and the reset slider 624, thereby biasing the reset slider 624 away from the lash adjustment screw 506 and body 402, i.e., out of the second bore 616. In an embodiment, the biasing element 634 is designed to consistently bias the e-foot 628 into contact with the second engine valve and with sufficient force between the respective shoulders to cause the body 402 and the motion receiving interface 404 to be biased toward, and preferably into contact with, the valve actuation motion source. In an alternative embodiment schematically illustrated in FIG. 1, an external resilient element or spring 150 is provided that reacts against a fixed surface 152 and the body 106 of the rocker arm 104 to thereby bias the motion source interface 108 toward, and preferably into contact with, the valve actuation motion source 124.

[0039] In an embodiment, travel of the reset slider 624 into the second bore 616 is limited when an upper surface of the reset slider abuts an upper wall of the second bore 616 and / or when the shoulder formed on the reset slider 624 to engage the spring 634 abuts a loser surface of the lash adjustment screw 506. On the other hand, travel of the reset slider 624 out of the second bore 616 is limited by the longitudinal length of the notch 630 and longitudinal position of the transverse pin 632 within the second bore 616. In an embodiment, travel of the reset slider 624 into the second bore 616 is configured to permit loss of any auxiliary valve actuations applied thereto while still ensuring solid contact between the reset slider 624 and upper wall of the second bore 616 to ensure conveyance of at least a portion of any main valve actuations applied thereto.

[0040] Thus configured, the hydraulic fluid present in the second hydraulic passage 512 is permitted to flow into the first bore 614 of the lash adjustment screw 506 where it is checked by the check ball 618, thereby retaining the locked volume of fluid in the actuator piston bore 504 and retaining the actuator piston 502 in its rigid / locked / extended state. As the rocker arm 400 rotates as commanded by a valve actuation (e.g., a main valve actuation), contact between the e- foot 628 and reset slider 624 with the second engine valve causes the spring 634 to compress (as the spring force of the engine valve spring is greater than the spring force of the spring 634) and to move the reset slider 624 upward in the second bore 616. At a point of sufficiently high valve actuation lift (i.e., position of the rocker arm 400), the resetting pin 626 makes contact with the check ball 618, thereby permitting the trapped fluid in the actuator piston bore 504, second hydraulic passage 512 and first bore 614 to be vented into the second bore 616 where one or more radially extending openings 621 permit the hydraulic fluid to further vent out the system. Subsequent upward travel of the rocker arm 400 will allow the reset pin 626 to lose contact withthe check ball 618 and once again permit a trapped volume of hydraulic fluid to be established in the actuator piston bore 504.

[0041] While the embodiment of FIGs. 4-6 describe the use of an actuator piston 502 solely controlled through the use of hydraulic fluid, those skilled in the art that will appreciate that hydraulically controlled mechanical locking mechanisms may be equally employed for this purpose. For example, U.S. Patent No. 9,016,249 (“the ‘249 Patent”) discloses various embodiments of a rocker arm comprising an actuator piston for contacting a single valve (as described above) that may be switched between its compliant / unlocked / retracted state and its rigid / locked / extended state using a horizontally sliding locking piston. The ‘249 Patent also discloses a reset piston disposed in a nose of the rocker arm and in hydraulic communication with the horizontally sliding locking piston in order to perform the same position-based resetting functions as the contact member assembly 516 as described above. Another example of a hydraulically controlled, mechanical locking that may be used in this manner is disclosed in U.S. Patent No. 9,790,824, which discloses a wedge-based locking mechanism.

[0042] Furthermore, while FIGs. 4-6 illustrate a resetting embodiment in which the reset function is incorporated into the contact member assembly 516, this is not a requirement. That is, as described above relative to FIGs. 1 and 10, the resetting function could instead be implemented by a rocker-arm-position-dependent reset component in fluid communication with the lost motion assembly 422 (i.e., the actuator piston bore 504) without need for the second hydraulic passage 512 or those elements of the contact member assembly 516 configured to provide the hydraulic resetting function. In this case, instant FIGs. 7 and 8 illustrate a contact member assembly 700 of the type illustrated and described in FIGs. 5 and 7 of U.S. Patent Application Publication No.2023 / 0151743. In this case, a reset slider 704 is slidably disposed within a lash adjustment screw 702 and biased outward by a spring 706, as shown in instant FIG. 7. As with the embodiment described above relative to FIG. 6, the reset slider 704 is travel limited to lose all auxiliary valve actuations but to transmit portions of main valve actuations when solid contact between the reset slider 704 and lash adjustment screw 702 is established as shown in instant FIG. 8. However, as further shown, the embodiment of instant FIGs. 7 and 8 does not require any elements used to perform the above-described hydraulic reset function.

[0043] FIG. 10 illustrates an internal combustion engine 1000 in which a valve actuation system 1002 comprises a second embodiment of a rocker arm 1004 in accordance with the instant disclosure. As depicted, components illustrated in FIG. 10 having like reference numbers to those illustrated in FIG. 1 have the same function. On the other hand, however, the system 1100 incorporates an integrated rocker arm 1004 in which a unitary body 1006 thereof supports a differently-configured motion source interface 1008 in that it requires only a single or first follower 1010 and the motion source 1024 requires only a first cam 1026 in order to implement both main and auxiliary valve actuations.

[0044] A schematic illustration of such a cam is provided in FIG. 11, which depicts a cam 1100 comprising a main valve actuation lobe 1102 and, in the illustrated example, two auxiliary valve actuation lobes 1104, 1106. The cam lobes 1102, 1104, 1106 are defined relative to a so-called base circle 1108 and sub-base circle 1110. In accordance with known techniques, the base circle 1108 and sub-based circle 1110 are separated by a radial distance, L, defining a maximum height for the auxiliary valve actuation lobes 1104, 1106 provided on the cam 1100. Such auxiliary lobes 1104, 1106, though resulting in auxiliary valve actuations in the rocker arm 1004 are onlyselectively conveyed by the lost motion component 116 and are lost, in all instances, by the stroke limited contact member 118 as described above. On the other hand, any portions of cam lobes greater than the height of the base circle 1108, e.g., the main valve actuation lobe 1102, are conveyed by the lost motion component 116 in all instances.

[0045] Referring now to FIGs. 12-15, an example of a rocker arm 1200 in accordance with the second embodiment of FIG. 11 (when configured for resetting operation) is illustrated. As shown, the rocker arm 1200 comprises a unitary body 1202 configured to span, in this case, two engine valves and rotate about a rocker shaft (not shown) received in a rocker shaft bore 1203. The rocker arm 1200 further comprises a motion source interface 1204 comprising one roller 1206 configured to receive valve actuation motions from the first cam 1026, as described above. The roller 1206 reside on a roller shaft 1314 (FIG. 13) disposed in a roller shaft bore 1214 formed in the body 1202. To minimize profile of the rocker arm 1200, the first roller 1206 is disposed in an opening 1210 formed in the body 1202, though this is not a requirement. Further still, and with additional reference to FIG. 15, the rocker arm 1200 comprises a valve interface 1216 that includes a lost motion component boss 1218 having an actuator piston assembly 1222 disposed in an actuator piston bore 1504 formed therein, a contact member boss 1220 having a contact member assembly 1516 disposed in a contact member bore 1508 formed therein, and a control valve boss 1240 having a control valve 1242 disposed in a control valve bore 1320 (FIG. 13) formed therein.

[0046] As shown in the cross-sectional view shown in FIG. 13 (taken along section line 13-13 in FIG. 12), the unitary body 1202 comprises a first hydraulic passage 1310 that extends from the rocker shaft bore 1203 to the control valve bore 1320. Once again, a rocker shaft (not shown) residing in the rocker shaft bore 1203 may comprise hydraulic passages in fluid communicationwith the first hydraulic passage 1310 and configured to provide hydraulic fluid thereto under the control of a suitable control device such as solenoid, as known in the art. As depicted, the first hydraulic passage 1310 passes through the roller shaft 1314 due to the configuration of the unitary body 1202. In this case, the roller shaft 1314 may be formed with an annular notch or recess (not shown) in its outer surface that is configured to align with the first hydraulic passage 1310, thereby allowing hydraulic fluid to flow through the first hydraulic passage 1310 and past the roller shaft 1314. As will be appreciated by those skilled in the art, a different configuration of the unitary body 1202 may permit formation of the first hydraulic passage 1310 without having to intersect with the roller shaft 1314. As further shown in FIG. 14 (taken along section line 14-141 in FIG. 12), the unitary body 1202 comprises a second hydraulic passage 1411 that extends from the control valve bore 1320 to the actuator piston bore 1504. In this manner, and as described above in connection with the embodiment of FIGs. 4-6, the control valve 1242 is able to regulate the establishment of a locked volume of hydraulic fluid in the actuator piston bore 1504.

[0047] With reference to FIG. 15, a cross-sectional view (taken along section line 15-15 in FIG. 12) is shown, particularly illustrating further details of the valve interface 1216. As illustrated, the actuator piston assembly 1222 and the contact member assembly 1516 are substantially identical in structure and operation to the actuator piston assembly 422 and the contact member assembly 516 illustrated and described with reference to FIG. 6 above. In the case of FIG. 15, the actuator piston bore 1504 and the contact member bore 1508 are in fluid communication with each other via a third hydraulic passage 1512. In this manner, and as previously described, the reset slider 1524 and lash adjustment screw 1506 operate to both lose auxiliary valve actuations and effectuate reset of the actuator piston 1502 based on position of the rocker arm 1200.

[0048] While the various embodiments in accordance with the instant 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. Accordingly, the preferred embodiments of the invention as set forth herein are intended to be illustrative only and not limiting so long as the variations thereof come within the scope of the appended claims and their equivalents.

Claims

AMENDED CLAIMS received by the International Bureau on March 3, 2026 (03.03.2026)Claims

1. 1. A rocker arm for actuating at least two engine valves in an internal combustion engine, comprising: a unitary body configured to span the at least two engine valves; a motion source interface supported by the body and configured to receive main valve actuations and auxiliary valve actuations from a motion source; a hydraulic control circuit supported by the body and configured to receive hydraulic fluid from a hydraulic fluid source; and a valve interface operatively supported by the body and operatively connected to the hydraulic control circuit, the valve interface being configured and selectively operable via the hydraulic control circuit to convey the main valve actuations to the at least two engine valves and to convey the auxiliary valve actuations to at least a first engine valve of the at least two engine valves, wherein the valve interface comprises a hydraulically controlled lost motion component that includes a swivel aligned with and configured to contact the first engine valve, and wherein the valve interface comprises a stroke limited contact member that includes another swivel aligned with and configured to contact a second engine valve of the at least two engine valves.

2. 2. The rocker arm of claim 1, wherein the motion source comprises a first cam and the motion source interface comprises a first roller configured to align with the first cam.- canceled -

3. 3. The rocker arm of claim 2, wherein the motion source comprises a second cam and the motion source interface comprises a second roller configured to align with the second cam.

4. - canceled -

5. - canceled -

6. 6. The rocker arm of claim 5, further comprising a spring configured to bias the stroke limited contact member into contact with the second valve and to bias the motion source interface toward the motion source.

9. The valve actuation system of claim 8, wherein the selectable coupling mechanism comprises a selectable hydraulic actuator and wherein the hydraulic actuator is retracted during the first state and is extended during the second state.

7. 7. The rocker arm of claim 5, wherein the stroke limited contact member is configured to cause a reset of the hydraulically controlled lost motion component based on position of the rocker arm.

8. 8. The rocker arm of claim 4, further comprising a reset component in hydraulic communication with the hydraulically controlled lost motion component and configured to cause a reset of the hydraulically controlled lost motion component based on position of the rocker arm.

9. 9. The rocker arm of claim 1, wherein the hydraulic control circuit comprises a control valve configured to receive the hydraulic fluid from the hydraulic fluid source and to provide the hydraulic fluid to a hydraulically controlled lost motion component aligned with the first engine valve.

10. 10. The rocker arm of claim 1, further comprising a spring operatively connected to the body and configured to bias the motion source interface toward the motion source.

11. 11. A valve actuation system comprising: the motion source providing the main valve actuations and auxiliary valve actuations; and the rocker arm in accordance with claim 1.

12. 12. The valve actuation system of claim 11, wherein the motion source comprises a first cam and the motion source interface comprises a first roller configured to align with the first cam.

13. 13. The valve actuation system of claim 12, wherein the first cam comprises a main lobe configured to provide the main valve actuations and at least one auxiliary lobe configured to provide the auxiliary valve actuations.

14. 14. The valve actuation system of claim 12, wherein the motion source comprises a second cam and the motion source interface comprises a second roller configured to align with the second cam.

15. 15. The valve actuation system of claim 14, wherein the first cam comprises a main lobe configured to provide the main valve actuations and the second cam comprises at least one auxiliary lobe configured to provide the auxiliary valve actuations.

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