PRIORITY

[1] This application claims the benefit under 35 U.S.C. § 119(e) of U.S. Provisional Patent Application No 63/287,582, filed 09 December 2021, the entire contents of which are hereby incorporated by reference for all purposes as if fully set forth herein.

TECHNICAL FIELD

[2] This disclosure generally relates to a rocker arm assembly for internal combustion engines, and more specifically to a switchable rocker arm (RA) assembly and a compression latch system assembly for deactivating the rocker arms.

BACKGROUND

[3] Global environmental and economic concerns regarding increasing fuel consumption and greenhouse gas emission, the rising cost of energy worldwide, and demands for lower operating costs are driving changes to legislative regulations and consumer demand. As these regulations and requirements become more stringent, advanced engine technologies are required to be developed and implemented to realize desired benefits.

[4] For internal combustion engines, many engineers utilize rocker arms to transfer the rotational motions of cams to linear motion that is appropriate for opening and closing engine valves. Deactivating rocker arms incorporate mechanisms that allow for selective activation and deactivation of the rocker arms. In a deactivated state, the rocker arm may exhibit lost motion movement. In order to return to an activated state from deactivated a state, the mechanism may require the rocker arm to be in a particular position or within a range of positions that may not be readily achieved while undergoing certain unconstrained movements while in the deactivated state, such as during excessive lash adjuster pump-up.

[5] Existing systems use cylindrical latches that face issues of shear, high contact pressures, material selection, and heat treatment processes that are balanced to enable the cylindrical latches. Additionally, clearances between mating components in the existing systems are required to be maintained very tight which causes extremely high contact pressure between the components of the rocker arms, and such systems cause lateral tolerance sacks-ups. There is a requirement for multiple components for retaining, hydraulic sealing and biasing. Thus, the existing systems use numerous components, and currently, the cylindrical latches are complex to use and install.

[6] Additionally, existing rocker arm brake systems use the lost motion principle. One problem with the conventional rocker arm brake system is related to the extension of valve overlap at the exhaust/intake which results in decreasing the braking performance. Moreover, a problem with opening a single valve is related to the extension of the exhaust/intake overlap and the opening up of an exhaust bridge is unbalanced during the initial normal exhaust lift which might result in engine overhead damage. The extended overlap allows exhaust gas to flow backward into the engine from the exhaust manifold and through the inlet valve into the inlet manifold. In other words, the extended valve overlap causes an undesired exhaust manifold air mass flow into the engine intake system, thus reducing exhaust stroke work and decreasing braking performance.

[7] Therefore, there is a need for reducing the number of components to achieve the lost motion principle and provide a compression latch system associated with a mechanism for deactivating rocker arms enabling switching between different lift heights during variable valve actuation modes.

[8] The background description provided herein is for the purpose of generally presenting the context of the disclosure. Work of the present named inventors, to the extent it is described in this background section, as well as aspects of the description that may not otherwise qualify as prior art at the time of filing, are neither expressly nor impliedly admitted as prior art against the present disclosure.

[9] The embodiments disclosed herein are only examples, and the scope of this disclosure is not limited to them. Particular embodiments may include all, some, or none of the components, elements, features, functions, operations, or steps of the embodiments disclosed herein. Embodiments according to the invention are in particular disclosed in the attached claims directed to a method, a storage medium, a system, and a computer program product, wherein any feature mentioned in one claim category, e.g., method, can be claimed in another claim category, e.g. system, as well. The dependencies or references back in the attached claims are chosen for formal reasons only. However, any subject matter resulting from a deliberate reference back to any previous claims (in particular multiple dependencies) can be claimed as well so that any combination of claims and the features thereof are disclosed and can be claimed regardless of the dependencies chosen in the attached claims. The subject matter which can be claimed comprises not only the combinations of features as set out in the attached claims but also any other combination of features in the claims, wherein each feature mentioned in the claims can be combined with any other feature or combination of other features in the claims. Furthermore, any of the embodiments and features described or depicted herein can be claimed in a separate claim and/or in any combination with any embodiment or feature described or depicted herein or with any of the features of the attached claims.

SUMMARY OF PARTICULAR EMBODIMENTS

[10] Embodiments of the present disclosure provide a rocker arm assembly that is related to a controlling mechanism by which relative motion between a cam side and a valve side engine rocker arm is managed. In particular, the rocker arm assembly utilizes a compression latch assembly replacing the use of sliding pins in pin bores. Integrating the latch system in the rocker arm assembly enables the latch system to act as a load transfer component between cam stems and valve stems. By using the latch system, the rocker arms including the cam side and the valve side may rotate independently of one another capable of different lost motions including, but not limited to, full lift, partial lift, and no-lift (zero lift).

[11] According to a particular embodiment, the rocker arm (RA) assembly includes a valve side rocker arm, a cam side rocker arm, and a latch system assembly. The valve side rocker arm may be configured to selectively rotate about a rocker shaft. The valve side rocker arm includes a radiused socket with a pivot interface and a seating surface that transitions from the pivot interface. The radiused socket in the valve side rocker arm may be, for example, a semi- spherical shaped socket, or of any shape that is configured to provide a pivotal fit to a side or edge of the latch system assembly. In an embodiment, the radiused socket may include an extended surface connecting the side length of the valve side rocker arm, forming angular portion together with radiused socket and pivot interface, keeping the latch system assembly in place while allowing the pivot and rocker arms for deactivation. In particular, the extended surface acts as a stop or limit to the amount of pivot allowed for the latch system assembly as per travel limit aspect. The seating surface of the valve side rocker arm ensures seating of the latch system assembly against it and against rocker arm halves, for example, enabling rotating about the rocker shaft in unison with the cam side and/or during displacing the latch system assembly away from the seating surface to rotate either or both of the valve side or the cam side independent of one another. The cam side rocker arm may be configured to selectively rotate about the rocker shaft independently of the valve side rocker arm. In a latched condition, the rocker arm assembly including the valve side rocker arm and the cam side rocker arm are configured to rotate about the rocker shaft in unison, for example, during a drive mode. In particular embodiments, the cam side rocker arm includes a latch interface that enables the cam side rocker arm to integrate into the latched condition to distribute force to the valve side rocker arm when the rocker arm assembly may be in the latched condition. While the cam side rocker arm may be selectively rotating about the rocker shaft, for example, the latch system assembly may be displaced away from the seating surface, the rocker arm assembly attains different lost motion modes based on Cylindrical Deactivation (CD A) modes of the rocker arm assembly in the internal combustion engine. For example, different lost motion modes may be associated with deactivating lift modes or profiles that may include, but are not limited to, switching between different lift profiles, for example, full lift height, partial lift height, intermediate lift height, zero lift height, or any other lift height or lift profile or lost motion.

[12] In a particular embodiment, the latch system assembly may be referred to as a biasing system that is a compression latch system for deactivating the exhaust rocker arm assembly. The latch system assembly may include a plate and an actuator. The plate may be referred to as a biased plate or a flap. The plate or the biased plate or the flap may be placed between the valve side rocker arm and the cam side rocker arm to receive and distribute compression forces from the latch interface when the cam side rocker arm rotates toward the valve side rocker arm while the rocker arm assembly is in the latched condition. In an embodiment, the plate may be light weighting plate that may be self-retained and may not require additional fasteners or clips at installation. Additionally, the plate may be shaped to balance light weighting and desired contact points corresponding to linking with the valve side rocker arm and the cam side rocker arm. With the usage of the plate that functions in compression, the latch system assembly provides a mechanism by which relative motion between the valve side rocker arm and the cam side rocker arm may be prevented. The plate includes a first plate side end and a second plate side end. The first plate side end is configured to rotate against the pivot interface of the valve side rocker arm. In an embodiment, the first plate side end of the plate may be of any shape or structure, or figure, to align against the pivot interface in the valve side rocker arm. For example, fully radiused to fit in the radiused socket in the valve side rocker arm, a chamfer shape, a bevel shape, a fillet shape, a round over, bullnose, and the like to align as a pivotal fit in the mating radiused socket to reduce the contact stresses. The radiused socket with the pivot interface may be included in the valve side and a seating surface that transitions from the pivot interface. The radiused socket in the valve side rocker arm may be, for example, a semi- spherical shaped socket, or of any shape that is configured to provide a pivotal fit to a side or edge of the latch system assembly. In an embodiment, the radiused socket may include an extended surface connecting the side length of the valve side rocker arm, forming angular portion together with radiused socket and pivot interface, keeping the latch system assembly in place while allowing the pivot and rocker arms for deactivation. In particular, the extended surface acts as a stop or limit to the amount of pivot allowed for the latch system assembly as per travel limit aspect. The second plate side end is configured to interface with the latch interface of the cam side rocker arm when the rocker arm assembly is in the latched condition, for example, during the drive mode for deactivating the rocker arm assembly via switching between the different lost motions that place the rocker arm assembly in different or a particular non-latched condition and/or placing the rocker arm assembly in a particular latched condition. In an embodiment, the second plate side end may be flat shaped which may be referred to as the nose of the plate which may be drafted between the latched condition and the different lost motions i.e., non-latched conditions. In an embodiment, the second plate side end may be drafted or moved according to a travel limit aspect, defined by the radiused socket with the pivot interface and the seating surface, that displaces the second side end away from the seating surface in a non-latched condition while pivoting the first side end in the pivot interface. For example, the travel limit aspect defines a wide angle of the plate closest to intersecting the rocker shaft and enables different lift profiles of the cam side rocker arm rotating about the rocker shaft independently of the valve side rocker arm during Cylinder Deactivation (CD A) mode. The actuator of the latch system assembly may be configured to selectively (a) seat the second side end of the plate against the seating surface to allow the plate to interface with the first latch interface so that the cam side rocker arm and the valve side rocker arm rotate about the rocker shaft in unison, and (b) displace the second side end away from the seating surface to allow the first latch interface to pass beneath the plate so that the cam side rocker arm rotates independently from the valve side rocker arm. In an example, the actuator may be spring and piston assembly. The latch system assembly or the rocker arm assembly may include a biasing component, for example, a spring to bias the plate against the seating surface. In an embodiment, the spring that may be the biasing component may be referred to as a biasing spring which may be a wire spring in a “U” shape. A predefined portion of the actuator including the spring and piston assembly or the spring alone may be coupled to the plate through a plate slot of the plate. For example, the biasing spring may include a plurality of staggered ends offset ends which may be coupled to the valve side rocker arm through one or more slots along the side lengths of the valve side rocker arm as shown in the figures. Further, in an exemplary embodiment, the biasing spring may be a bent wire spring that is configured to bias the plate in a drive mode position in the latched condition and move the plate in the different lost motion modes or lift profiles pushing the plate away from the seating surface which places the rocker arm assembly and the latch system assembly in a particular nonlatched condition or lost motion or lift profile. The latch system assembly or the rocker arm assembly may include one or more movable pistons configured to switch between (a) an extended state in which the one or more movable pistons push the plate away from the seating surface, thereby placing the rocker arm assembly in a non-latched condition, and (b) a retracted state in which the plate may be allowed to seat against the seating surface, thereby placing the rocker arm assembly in the latched condition.

[13] Particular embodiments, disclose a latch system assembly that may utilize a lost motion spring system for deactivating rocker arm (RA) assembly enabling a cam side rocker arm to rotate about the rocker shaft independently of a valve side rocker arm. The latch system assembly may be a compression latch system that may be a biasing system that may include a plate, actuator, a biasing component, for example, a spring, and one or more movable pistons. The plate may be referred to as a biased plate or a flap that may be placed between the valve side rocker arm and the cam side rocker arm to receive and distribute compression forces from the latch interface when the cam side rocker arm rotates toward the valve side rocker arm while the rocker arm assembly is in the latched condition. In an embodiment, the plate may be light weighting plate that may be self-retained and may not require additional fasteners or clips at installation. With the usage of the plate that functions in compression, the latch system assembly provides a mechanism by which relative motion between the valve side rocker arm and the cam side rocker arm may be prevented. The plate includes a first plate side end and a second plate side end. The first plate side end is configured to rotate against the pivot interface of the valve side rocker arm. In an embodiment, the first plate side end of the plate may be of any shape or structure, or figure, to align against the pivot interface in the valve side rocker arm. For example, fully radiused to fit in the radiused socket in the valve side rocker arm, a chamfer shape, a bevel shape, a fillet shape, a round over, bullnose, and the like to align as a pivotal fit in the mating radiused socket to reduce the contact stresses. The second plate side end is configured to interface with the latch interface of the cam side rocker arm when the rocker arm assembly is in the latched condition, for example, during the drive mode for deactivating the rocker arm assembly via switching between the different lost motions that place the rocker arm assembly in different or a particular non-latched condition and/or placing the rocker arm assembly in a particular latched condition. In an embodiment, the second plate side end may be flat shaped which may be referred to as the nose of the plate which may be drafted between the latched condition and the different lost motions i.e., non-latched conditions. In an embodiment, the second plate side end may be drafted or moved according to a travel limit aspect, defined by the radiused socket with the pivot interface and the seating surface, that displaces the second side end away from the seating surface in a non-latched condition while pivoting the first side end in the pivot interface. For example, the travel limit aspect defines a wide angle of the plate closest to intersecting the rocker shaft and enables different lift profiles of the cam side rocker arm rotating about the rocker shaft independently of the valve side rocker arm during Cylinder Deactivation (CD A) mode. The actuator of the latch system assembly may be configured to selectively (a) seat the second side end of the plate against the seating surface to allow the plate to interface with the first latch interface so that the cam side rocker arm and the valve side rocker arm rotate about the rocker shaft in unison, and (b) displace the second side end away from the seating surface to allow the first latch interface to pass beneath the plate so that the cam side rocker arm rotates independently from the valve side rocker arm. In an example, the actuator may be spring and piston assembly. The latch system assembly or the rocker arm assembly may include a biasing component, for example, a spring to bias the plate against the seating surface. In an embodiment, the spring that may be the biasing component may be referred to as a biasing spring which may be a wire spring in a “U” shape. A predefined portion of the actuator including the spring and piston assembly, or the spring alone may be coupled to the plate through a plate slot of the plate. For example, the biasing spring may include a plurality of staggered ends offset ends which may be coupled to the valve side rocker arm through one or more slots along the side lengths of the valve side rocker arm as shown in the figures. Further, in an exemplary embodiment, the biasing spring may be a bent wire spring that is configured to bias the plate in a drive mode position in the latched condition and move the plate in the different lost motion modes or lift profiles pushing the plate away from the seating surface which places the rocker arm assembly and the latch system assembly in a particular non-latched condition or lost motion or lift profile. The latch system assembly or the rocker arm assembly may include one or more movable pistons configured to switch between (a) an extended state in which the one or more movable pistons push the plate away from the seating surface, thereby placing the rocker arm assembly in a non-latched condition, and (b) a retracted state in which the plate may be allowed to seat against the seating surface, thereby placing the rocker arm assembly in the latched condition.

[14] Embodiments disclose lower component counts and low-cost latch assembly and rocker arm assembly. The latch system assembly provides a self-retained biasing system and wider tolerances between the components of the rocker arm assembly overcoming the drawbacks of the existing systems. The plate and the actuator together balance light weighting and desired wide tolerances of the contact points of the cam side and the valve side. The latch system assembly prevents overloading the engine system both mechanically and thermally along with achieving quiet operation. In particular embodiments, the rocker arm assembly, and/or the latch system assembly may be configured to switch between different latched conditions that define a number of latch positions, which are based upon a number of drive modes.

[15] The embodiments disclosed herein are only examples, and the scope of this disclosure is not limited to them. Particular embodiments may include all, some, or none of the components, elements, features, functions, operations, or steps of the embodiments disclosed herein. The dependencies or references back in the attached claims are chosen for formal reasons only. However, any subject matter resulting from a deliberate reference back to any previous claims (in particular multiple dependencies) can be claimed as well, so that any combination of claims and the features thereof are disclosed and can be claimed regardless of the dependencies chosen in the attached claims. The subject matter which can be claimed comprises not only the combinations of features as set out in the attached claims but also any other combination of features in the claims, wherein each feature mentioned in the claims can be combined with any other feature or combination of other features in the claims. Furthermore, any of the embodiments and features described or depicted herein can be claimed in a separate claim and/or in any combination with any embodiment or feature described or depicted herein or with any of the features of the attached claims. Additional objects and advantages will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the disclosure. The objects and advantages will also be realized and attained by means of the elements and combinations particularly pointed out in the appended claims. It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the claimed invention.

BRIEF DESCRIPTION OF THE DRAWINGS

[16] FIG .1 illustrates a perspective view of a rocker arm assembly having a latch system assembly linking to a valve side rocker arm and a cam side rocker arm, according to an example of the present disclosure;

[17] FIG. 2a, and FIG. 2b illustrates a straight perspective view and cut sectional view respectively of the rocker arm assembly of FIG. 1, according to particular embodiments of the present disclosure;

[18] FIG. 3a illustrates a perspective view of the latch system assembly of FIG. 1, according to particular embodiments of the present disclosure;

[19] FIG. 3b illustrates a sectional view of the latch system assembly of FIG. 3a, according to particular embodiments of the present disclosure;

[20] FIG. 3 c illustrates a top perspective view of the latch system assembly of FIG. 3 a, according to particular embodiments of the present disclosure;

[21] FIG. 4 illustrates a cross-section view of FIG. 3c that shows the latch system assembly in a latched condition, according to particular embodiments of the present disclosure;

[22] FIG. 5 illustrates a cross-section of FIG. 3c, which shows an example of a lift profile of the latch system assembly at a base circle, according to particular embodiments of the present disclosure;

[23] FIG. 6 illustrates a cross-section of FIG. 3c, which shows an example of a lost motion of the latch system assembly, according to particular embodiments of the present disclosure; [24] FIG. 7 illustrates a cross-section of FIG. 3 c, which shows an example of a movable piston pressing up on the plate of the latch system assembly for performing lift profiles, according to particular embodiments of the present disclosure;

[25] FIG. 8a illustrates movable pistons and the latched condition of the rocker arm assembly, according to particular embodiments;

[26] FIG. 8b illustrates an intermediate mode of the lift profile of the plate at the base circle, according to particular embodiments;

[27] FIG. 8c illustrates an intermediate mode of the lift profile of the plate at the partially lost motion, for example, a second lift profile, according to particular embodiments;

[28] FIG. 9 illustrates various lost motion angles and latch angles during deactivating rocker arm assembly, according to particular embodiments of the present disclosure; and

[29] FIG. 10 illustrates an example related to the movement of the cam side rocker arm independently of the valve side rocker arm, according to particular embodiments of the present disclosure.

DETAILED DESCRIPTION

[30] In the following description, for the purposes of explanation, numerous specific details are set forth in order to provide a thorough understanding of the present invention. It will be apparent, however, that the present invention may be practiced without these specific details. In other instances, well-known structures and devices are shown in block diagram form in order to avoid unnecessarily obscuring the present invention.

[31] Reference will now be made in detail to the examples which are illustrated in the accompanying drawings. Directional references such as “left” and “right” are for case of reference to the figures. This description of exemplary embodiments is intended to be read in connection with the accompanying drawings, which are to be considered part of the entire written description. In the description, relative terms such as “horizontal,” “vertical,” “front,” “rear,” “upper,” “lower,” “top,” and “bottom”, as well as derivatives thereof (e.g., “horizontally,” “downwardly,” “upwardly,” etc.), should be construed to refer to the orientation as then described or as shown in the drawing figure under discussion and to the orientation relative to a vehicle body. These relative terms are for convenience of description and normally are not intended to require a particular orientation. Terms concerning attachments, coupling, and the like, such as “connected” and “interconnected,” refer to a relationship wherein structures are secured or attached to one another either directly or indirectly through intervening structures, as well as both movable or rigid attachments or relationships unless expressly described otherwise. The term “operatively connected” is such an attachment, coupling, or connection that allows the pertinent structures to operate as intended by virtue of that relationship. Additionally, the words “a” and/or “an” as used in the claims mean “at least one”.

[32] With reference to FIG. 1, a rocker arm (RA) assembly 100 for an internal combustion engine is shown. The rocker arm assembly 100 may be a deactivating rocker arm assembly in an exhaust engine rocker and as a type III center pivot. In an embodiment, the rocker arm assembly 100 may be a lost motion type provided with automatic hydraulic adjusting and resetting functions. The rocker arm assembly 100 includes an outer arm, for example, a valve side rocker arm 102, and an inner arm, for example, a cam side rocker arm 106. The rocker arm assembly 100 also includes a rocker shaft 104 about which the valve side rocker arm 102 and the cam side rocker arm 106 may rotate in a latched condition. During the latched condition, the valve side rocker arm 102 and the cam side rocker arm 106 may rotate about a rocker shaft in unison with no relative motion between them, for example, during the drive mode of the engine.

[33] Referring to FIG. 1 , FIG. 2a, and FIG. 2b, in particular embodiments, the valve side rocker arm 102 (from FIG. 1) and 202 (from FIG. 2) include a radiused socket 210 (in FIG. 2a and 2b), which acts as a mating radiused socket for fitting a side 210a of the latch system assembly 108 pivotally in the radiused socket. As an example, the radiused socket 210 in the valve side rocker arm 202 may be, for example, a semi-spherical shaped socket, rounded shaped, or of any shape that is configured to provide a pivotal fit to a side 210a or edge of the latch system assembly 214. In an embodiment, the radiused socket 210 may include an extended surface connecting the side length (first side length 102a and second side length 102b) of each side of the valve side rocker arm 202, forming an angular portion together with radiused socket 210 and pivot interface 210a. In this manner, the latch system assembly 214 in place while allowing the pivot and rocker arms for deactivation. In particular, the extended surface acts as a stop or limit to the amount of pivot allowed for the latch system assembly 214 as per travel limit aspect. In particular, the radiused socket 210 includes the pivot interface 210a interfacing with the side 212 or edge 212 of the latch system assembly 214. For example, FIG. 2a shows one of the side lengths 102b of the valve side 202.

[34] The valve side rocker arm 202 further includes a seating surface 216 to ensure seating of the latch system assembly against it and against the rocker arm halves, for example, enabling rotating about the rocker shaft in unison with the cam side and/or during displacing the latch system assembly away from the seating surface to rotate either or both of the valve side or the cam side independent of one another. In an embodiment, the radiused socket 210 with the pivot interface 210a and the seating surface 216 along with the extended surface joining the radiused socket 210 on one side and other side forming connection with side length 102a, 102b of each side of the valve side rocker arm 202, defines a travel limit aspect for the latch system assembly 214. In particular, the latch system 214 may be drafted or moved according to angular movement defined with respect to the travel limit aspect. For example, in a non-latched condition, the latch system assembly 214 may be displaced away from the seating surface 216 enabled by linking the side of the latch system assembly 214 pivotally in the pivot interface 210a. For example, the travel limit aspect defines a wide angle, for moving the latch system assembly, closest to intersecting the rocker shaft and enables different lift profiles of the cam side 206 rotating about the rocker shaft 204 independently of the valve side rocker arm 202 during Cylinder Deactivation (CDA) mode. In particular examples, the travel limit aspect defines the way a plate of the latch system assembly 214 may be moved like a flap up to a certain degree of angle which is described in detail referring to FIG. 9, with one end linked to the pivot interface 210a and other end moving up and down movement for switching between different latch steps and different lift profiles. Using the time limit aspect associated with the radiused socket 210 and the pivot interface 210a, the functions and operations of deactivating rocker arm assembly 200 may be achieved that enables the valve side rocker arm 202 and the cam side rocker arm 206 to rotate and move independently from one another during the CDA mode. In an embodiment, the radiused socket 210 with the pivot interface 210a along with the travel limit aspect performs switching between different latched conditions or latch steps and different lost motions or lift profiles relative to the rocker shaft 204. The different latched conditions or latch steps include, but are not limited to, full latch, partial latch, intermediate latch, and the different lost motion modes include, but not limited to, full lift, partial lift, intermediate lift, and no-lift (zero lift). [35] The valve side rocker arm 102 includes one or more slots denoted as 110 in FIG. 1 and as 208 in FIG. 2a and FIG. 2b. FIG. 2b shows cut sectional perspective view, for example, internal perspective of the rocker arm assembly 200 illustrating the side length 102a and hiding the side length 102b (not shown). The one or more slots 208 may be configured to engage the latch system assembly 214 during installation for enabling different lost motion modes and different latch steps. The one or more slots 208 may be of any shape, for example, round holes, square grooves, or any other shaped cavity according to which an actuator and/or a biasing component, for example, a biased spring of the latch system assembly 214 may be engaged or mated into as a perfect fit preventing inadvertent disassembling of the whole latch system assembly 214. In an embodiment, the valve side rocker arm 202 may include a variety of additional components, units, and aspects, for example, a lash adjuster, deactivating capsule, engine brake capsule, and other units. The valve side rocker arm 202 may be associated with or connected to or linked with an engine valve stem that may connect directly or indirectly at an elephant foot (e-foot) or the like, and also valve bridges and other valve connections may be used for deactivating the rocker arm assembly 200.

[36] In particular embodiments, the cam side rocker arm 206 of the rocker arm assembly 200 may be configured to engage with the rocker shaft 104/204 during the latched conditions and selectively rotate about the rocker shaft 104/204 independently of the valve side rocker arm 102/202. More specifically, the cam side rocker arm 206 may be configured to selectively rotate about the rocker shaft 204 independently of the valve side rocker arm 202. From FIG. 2a and 2b, the cam side rocker arm 206 includes a first latch interface 212. In an embodiment, the latch interface 212 may be configured to integrate into the latched condition that enables to distribute force to the valve side rocker arm 202 when the rocker arm assembly 200 may be in the latched condition on the common rocker shaft 204 with no relative motion between them, for example, during the drive mode of the engine. In an example, the latch interface 212 may be flat shaped or the cam side rocker arm 206 may be configured with a socket for engaging with the latch system assembly 214. While the cam side rocker arm 206 may be selectively rotating about the rocker shaft 204, for example, the latch system assembly may be displaced away from the seating surface 216, the rocker arm assembly 200 attains different lost motion modes based on the CDA modes of the rocker arm assembly 200 in the internal combustion engine. For example, different lost motion modes may be associated with deactivating lift modes or profiles that may include, but are not limited to, switching between different lift profiles, for example, full lift height, partial lift height, intermediate lift height, zero lift height, or any other lift height or lift profile or lost motion.

[37] In particular embodiments, the rocker shaft 204 may be a common rocker shaft that may be associated with a pivot axle (not shown) enabling the valve side rocker arm 202, and the cam side rocker arm 206 may pivot by rotating around the pivot axle. In an embodiment, the valve side rocker arm 202 and the cam side rocker arm 206 may be connected or linked with a pivot location that may be shared about the rocker shaft 204, by extending a portion of the cam side rocker arm 206 around a rocker shaft bore (not shown) coupled to the rocker shaft 204 and eliminating the pivot axle. The rocker shaft bore that may be coupled to the rocker shaft 204 enables to supply of pressurized control fluid to the rocker arm assembly 200. Then, internal oil channels may supply control fluid, for example, to enable hydraulic lash adjustment and plate/flap movement of the latch system assembly 214, or to enable engine braking or cylinder deactivation functionality. In an embodiment, an oil channel in a valve side latch body of the valve side rocker arm 202 may supply control fluid to the latch system assembly 214 and an oil channel in a cam side latch body of the cam side rocker arm 206 may supply a separate control fluid. The oil channels connect to receive fluid from the rocker shaft bore and the oil channels may be formed for additional functionality, for example, an EEVO (early exhaust valve opening) control fluid. The oil channels may be drilled or cast or otherwise formed into the rocker arm assembly 200, and in some alternatives, plugs may be used to fluidly seal the ends of the oil channel. The oil channels may be coupled to the hydraulic pistons of the latch system assembly for control fluid supply, described in later sections herein with respect to FIG. 8c, FIG. 9, and FIG. 10.

[38] In particular embodiments, the latch system assembly 214 may be seated on the seating surface 216, with one end of the latched system assembly 214 pivotally linked to the pivot interface 210a, ensuring seating of the latch system assembly 214 against rocker arm halves. In particular, the seating surface 216 enables a plate portion of the latch system assembly 214 to act as a flap with one end pivotally fixed to the pivot interface 210a in the radiused socket 210 and the other end being movable freely between different lost motion interfaces of the cam side rocker arm 206 during CDA mode or different lost motion modes. Referring to FIG. 2b, the one or more slots 314 may be shown as cut portions to explain a better view of the biasing component, for example, spring.

[39] Referring to FIG. 3a, FIG. 3b, and FIG. 3c, an exemplary latch system assembly 300 may be illustrated that may operate as a mechanical latch system for deactivating the rocker arm assembly. In particular, the latch system assembly 300 may be a biasing system and a compression latch system that replaces the use of sliding pins in pin bores for the rocker arm assembly. For example, the compression latch system assembly 300 being the biasing system may bias the compression latch to ensure seating against the rocker arm halves. In an embodiment, the latch system assembly 300 may include a plate 302, and an actuator (for example, spring 310 and movable pistons 316 assembly). The plate 302 may be referred to as a biased plate or a flap when combined with the biasing component, for example, with the spring 310. The plate 302 or the biased plate may be in the form of a flap that may be placed between the valve side rocker arm 202 and the cam side rocker arm 206. In an embodiment, the seating surface 216 may act as a seat for the plate 302. The plate 302 may be a light weighted plate that may be self-retained (with the use of the spring 310) and thus may not require additional fasteners or clips at installation. In an embodiment, the plate 302 may be shaped to balance light weighting and desired contact points corresponding to link with the valve side rocker arm 202 and the cam side rocker arm 206. For example, the plate 302 may be shaped in various forms, such as a trapezoidal shape with a thickness that aligns and pivots at the pivot interface 210a of the valve side rocker arm 202 and fits at the first latch interface 212 of the cam side rocker arm 206. In this manner, the plate 302 may be configured to receive and distribute compression forces to and from the valve side rocker arm 202 and the cam side rocker arm 206 respectively to rotate both valve side rocker arm 202 and the cam side rocker arm 206 in unison about the rocker shaft 204. The plate 302 may be made of any material, for example, a metal component. The plate 302 includes a first plate side 304 end and a second plate side end 306. The first plate side end 304 may be configured to rotate against the pivot interface of the valve side rocker arm 202. In an embodiment, the first plate side end 304 of the plate 302 may be of any shape or structure, or figure, to align against the pivot interface in the valve side rocker arm. For example, first plate side end 304 may be fully radiused to fit in the radius socket 210 in the valve side rocker arm 202, to align as a pivotal fit in the mating radiused socket to reduce the contact stresses. In an embodiment, the first plate side end 304 of the plate 302 may be of any shape or structure, or figure, to align with the pivot interface 210a in the valve side rocker arm 202. In particular, the first plate side end 304 may be configured to be received in the radius socket 210 of the valve side rocker arm 202. For example, the first plate side end 304 may be rounded to pivot in the radius socket 210 at the pivot interface 210a, and/or fully radiused to fit in the mating radius socket 210 in the valve side rocker arm 304. In this way, during the drive mode or in the latched condition, the plate 302 (compression latch plate) may be reacted by the radiused socket 210 in the valve side rocker arm 202, forcing rotation of all components of the rocker arm assembly 200 in unison and the engine valve(s), actuated in the drive mode. As another example, the first plate side end 304 may be a chamfer shape, a bevel shape, a fillet shape, a round over, a bullnose, and the like to pivotally fit in the mating radius socket 210 to reduce the contact stresses. In an embodiment, the second plate side end 306 may be configured to couple with the latch interface 212 in the latched condition during the drive mode and the one or more lost motion interfaces for deactivating the rocker arm assembly via switching between the different lost motions and the latched condition. In particular embodiments, the second plate side end 306 may be configured to interface with the first latch interface 212 of the cam side rocker arm 206 when the rocker arm assembly 200 may be in the latched condition, for example, during the drive mode for deactivating the rocker arm assembly 200 via switching between the different lost motions that place the rocker arm assembly 200 in different or a particular non-latched condition and/or placing the rocker arm assembly in a particular latched condition. In an embodiment, the second plate side end 306 may be of a shape that aligns and fits at the first latch interface 212. For example, the second plate side end 306 may be flat-shaped to match the flat latch interface or a shape or may be referred to as the nose of the plate 302 which may be drafted between the latched condition and the different lost motions i.e., non-latched conditions, etc., based on matching the shape of the second plate side end 306 with the socket shape of the first latch interface 212 of the cam side rocker arm 206. In this manner, the cam side rocker arm 206 may be rotating due to the cam force during the latched condition, where the rotation is being reacted at the flat end of the compression-biased plate 302 (latch plate), actuating it to rotate in unison with the valve side rocker arm 202, that may be actuated in the drive mode. In an embodiment, the second plate side end 306 may be drafted or moved according to the travel limit aspect, defined by the radiused socket 210 with the pivot interface 210a and the seating surface 216, which displaces the second plate side end 306 away from the seating surface 216 in a non-latched condition while pivoting the first side end 304 in the pivot interface 210a. This displacement of the second plate side end 306 enables different lift profiles of the cam side rocker arm 206 rotating about the rocker shaft 204 independently of the valve side rocker arm during Cylinder Deactivation (CD A) mode. Further, in this way, the plate 302 may be pivoted clear to allow the relative motion for CDA or lost motion or different latch steps. Additionally, the plate 302 may be configured to be free of shear issues and may be able to distribute contact pressures in a durable and reliable manner. In particular, with the usage of the plate 302 that functions in compression, the latch system assembly provides a mechanism by which relative motion between the valve side rocker arm 202 and the cam side rocker arm 206 may be prevented. For example, component stress is low on the valve side rocker arm 202 and the plate 302 (latch plate). In an embodiment, the plate 302 may be pivoted from one latched condition or latch step to another latched condition or latch step, for example, from a first latch step to a second latch step and/or from the first latch step to the lost motion position. In an embodiment, the plate 302 includes a plate slot 308 which may be any of, not limited to, groove, hole, cavity, crevice, through-hole, and the like, to which a predefined portion of the actuator (310 and 316) or a biasing component 310 for example, may be coupled.

[40] In particular embodiments, the actuator (combination of spring 310 and pistons 316 as an example) of the latch system assembly 300 may be configured to selectively (a) seat the second plate side end 306 of the plate 302 against the seating surface 216 to allow the plate 302 to interface with the first latch interface 212 so that the cam side rocker arm 206 and the valve side rocker arm 202 rotate about the rocker shaft 204 in unison, and (b) displace the second plate side end 306 away from the seating surface 216 to allow the first latch interface 212 to pass beneath the plate 302 so that the cam side rocker arm 206 rotates independently from the valve side rocker arm 204. In an example, the actuator may be a spring 310 and piston 316 assembly. The actuator may include a predefined portion that may be coupled to the plate slot 308.

[41] In particular embodiments, the spring 310 of the compression latch system assembly 300 includes a predefined portion and a plurality of staggered offset ends 312 and 314. In an embodiment, the spring 310 may be a biasing component and a biasing spring to bias the plate 302 against the seating surface 216. The biasing spring 310 may be a wire spring roughly formed in a “U” shape. The predefined portion of the spring 310 may be defined by bent portions coupled into the plate slot 308 of the plate 302. The plurality of staggered ends offset ends 312 and 314 may be coupled to the valve side rocker arm through the one or more slots 110 (FIG. l)/208 (FIG.2a, and b). Referring to FIG. 3a, FIG. 3b, and FIG. 3c, the one or more slots may be shown as cross-section and cut portions without side length 102b (for example side length 102b of the valve side may be hidden for this particular embodiment to explain a better internal perspective view of the valve side and latch system assembly connection with the valve side) of the valve side into which the slots 208 may be included connecting the spring ends 312 and 314. For example, each side length of the staggered offset ends 312 and 314 bends to couple or engage into mating holes or slots 208 within the interior of the valve side rocker arm 202. The offset in the side lengths of the wire spring 310 provides the spring feature in the bias direction and enables the biasing component like the plate 302 and the latch system assembly (biasing system) with self-retainment and self-retractable features that may not need additional fasteners or clips at installation. As an example, the U-shaped spring 310 including the staggered ends 312 and 314 affects the spring force K. In an embodiment, the installation may be achieved by squeezing the sides 312 and 314 of the spring 310 together to fit inside the cam side rocker arm 206 and the mating holes 208 of the valve side rocker arm 202 and any subsequent release of the spring sides 312 and 314 retains the wire spring 310 in the valve side rocker arm 202, thereby preventing inadvertent disassembly. In an example, the spring 310 mounts may be cross drilled through the rocker arm half. In an embodiment, the spring 310 and the plate 302 together along with hydraulic pistons 306 enable to move the plate 302 for the lost motion valve lift profiles, including zero lift profiles, intermediate lift profiles, full lift profiles, and also different latch steps when the latch system assembly may be configured for lost motion modes and/or for different latch steps in the different drive modes. In this way, the deactivating rocker arm assembly 100 and/or the latch system assembly 300 may be regarded as a lost motion spring system.

[42] Referring to FIG. 3b, the one or more movable pistons 316 of the compression latch system assembly 300 may be coupled between the plate 302 and the rocker shaft (204 in FIG. 2) for enabling hydraulic control to the biased plate 302 switching between different latched conditions and the different lost motion modes. In an embodiment, the movable pistons 316 may be coupled to the plate 302 through a cut-through hole from the rocker shaft 204. The movable pistons 316 may be hydraulic pistons and/or actuating solenoids for hydraulic feed and hydraulic control that may be supplied through the rocker shaft (204). In one example, for CD A mode, the one or more movable pistons 316 being hydraulic pistons may be pushed on and subsequently pivot the compression latch plate 302 about different full radius interface. Once fully pivoted, the cam side rocker arm 206 may be free to rotate on the rocker shaft 204 independent of the valve side rocker arm 202. In particular, one or more movable pistons 316 configured to switch between (a) an extended state in which the one or more movable pistons 316 push the plate 302 away from the seating surface 216, thereby placing the rocker arm 202 assembly in a non-latched condition, and (b) a retracted state in which the plate 302 may be allowed to seat against the seating surface 216, thereby placing the rocker arm assembly 200 in the latched condition. FIG. 3 c shows a top perspective view and cut perspective of the latch system assembly 300 of FIG. 3a (hiding side lengths 102a, 102b and radiused socket and pivot interface and surface extending from the radiused socket and connecting the side lengths of the valve side). The dashed lines denoted by A, B, and C as cut or cross sections for the view that are shown in FIG. 4 showing cross section view for A, FIG. 7 showing cross section view for B and FIG. 5, and FIG. 6 showing cross section view for C, in detail perspective.

[43] Referring to FIG. 4 which illustrates a cross-section view for portion A in FIG. 3 c, showing side length 102a and another side length hidden showing internal perspective view of the valve side coupled with spring ends. FIG. 4 shows the latch system assembly 400 in a latched condition 402. In the latched condition 402, the valve side rocker arm 202 and the cam side rocker arm 206 are rotated in unison on the common rocker shaft 204 with no relative motion between them, for example, during the drive mode of the engine along with forcing all the components like the engine valves in unison, actuated in the drive mode. Here, in FIG. 4 the biasing component, for example, the spring may be shown as coupled to one of the slots as an example, and such a figure is a non-limited embodiment. There may be different ways to couple ends of the spring to any of the slots.

[44] Referring to FIG. 5 may be a cross-section for portion C of FIG. 3c, showing side length 102a and another side length hidden showing internal perspective view of the valve side coupled with spring ends. FIG. 5 shows an example of a lift profile of the latch system assembly 500 at a base circle. In an embodiment, For CDA mode, for example, at the base circle, the one or more movable pistons 506 being hydraulic pistons may be lifted up that lifts up and subsequently pivots the compression latch plate 502 about different full radius interface denoted by 508 in FIG. 5. The spring 504 and the movable piston 506 enables the nose of the plate 502 to be drafted up to an angle controlled within the travel limit aspect defined with respect to the radius socket and pivot interface of the valve side rocker arm. The travel limit aspect establishes a wide angle of the plate 502 closest to intersecting the rocker shaft enabling a full lift profile and freeing the cam side rocker arm to rotate on the rocker shaft independent of the valve side rocker arm once fully pivoted.

[45] Referring to FIG. 6 may be a cross-section for portion C of FIG. 3c, showing side length 102a and another side length hidden showing internal perspective view of the valve side coupled with spring ends. FIG. 6 shows an example of a lost motion of the latch system assembly 600, achieved via pressing of the piston moving the plate 602 upward through angular movement denoted by 608. Here in FIG. 6, the one or more slots may be shown as cross-sections and cut portions with no covering for the slots to which the spring ends 312 and 314 are connected, to explain a better view of the biasing component as an exemplary embodiment. In an embodiment, FIG. 6 shows an example of a partial life profile where one piston 606 may be shown pressing up on the plate 602 during CDA mode or lost motion mode. In an embodiment, any number of pistons may be installed. The hydraulic feed may be ported through the rocker arm and hydraulic control may be supplied through the rocker shaft. In an embodiment, the angles of plate 602 may facilitate mating and stress distribution or angles may limit adhesion or stiction-type issues with respect to achieving an appropriate set travel limit aspect of the radius socket of the valve side rocker arm.

[46] Referring to FIG. 7 may be a cross-section for portion B of FIG. 3c, showing side length 102b covering another side length showing a straight perspective view of the valve side coupled with slots 208. FIG. 7 shows an example of a movable piston 704 pressing up on the plate 702 of the latch system assembly 700 for performing lift profiles. In this scenario of the latched condition, the plate 702 receives and distributes compression forces. In particular, the plate 702 may be enabled with reaction loads that may be compressive and may be distributed across surfaces towards and from the valve side rocker arm and the cam side rocker arm. In this manner, the reaction surface of the valve and cam side may be drafted that prevents pop out of the assembly. Further, the rocker arm assembly 700 achieves wider tolerance, that depends upon application of the latch system assembly, types of rocker arms, type of engines and different types of combustion engines. In particular, the tolerance may be double the tolerance allowance of the existing systems.

[47] Referring to FIG. 8a, FIG. 8b, and FIG. 8c illustrates movable pistons 802 and 804. In an embodiment, any number of pistons may be installed. The hydraulic feed may be ported through the rocker arm and hydraulic control may be supplied through the rocker shaft. In an embodiment, rocker arm assembly may utilize internal oil channels that may supply control fluid, for example, to enable hydraulic lash adjustment and plate/flap movement of the latch system assembly, or to enable engine braking or cylinder deactivation functionality. In an embodiment, an oil channel in a valve side latch body of the valve side rocker arm may supply control fluid to the latch system assembly and an oil channel in a cam side latch body of the cam side rocker arm may supply a separate control fluid. The oil channels connect to receive fluid from the rocker shaft bore and the oil channels may be formed for additional functionality, for example, an EEVO (early exhaust valve opening) control fluid. The oil channels may be drilled or cast or otherwise formed into the rocker arm assembly, and in some alternatives, plugs may be used to fluidly seal the ends of the oil channel. The oil channels may be coupled to the hydraulic pistons of the latch system assembly for control fluid supply.

[48] FIG. 8a illustrates an intermediate latched condition or latch step 800 during or in drive mode. In an example, FIG. 8a shows two latch steps for mating the plate in the cam side rocker arm that yields two drive modes. In an embodiment, switching between the latching step and lost motions may occur at the base circle of the cam. The rocker assembly and the latch system assembly may be added with independent oil pots with a predetermined diameter of pistons, for example, two diameter pistons and ferrule (shown around 804). The ferrule may be pressed in that may limit the travel of the intermediate piston 804.

[49] Referring to FIG. 8b which illustrates an intermediate mode of the lift profile 812 of the plate at the base circle, according to particular embodiments. The pistons 802 and 804 move the plate at the base circle, for example, at the base circle the plate may be lifted fully via hydraulic control achieving a full lift profile. FIG. 8c illustrates an intermediate mode of the lift profile 814 of the plate at the partially lost motion, for example, a second lift profile 814. The numerals 806 and 810 shows different latch interfaces of the cam side to achieve different lift profile, for example, partial or full lift profile. [50] FIG. 9 illustrates various lost motion angles and latch angles during deactivating rocker arm assembly, according to particular embodiments. In an embodiment, the compression latch system assembly may include the plate tangential to the rocker shaft during lift and lowering.

[51] LM° > DM1 °, DM2°

[52] In an embodiment, the lost motion (LM) may achieve the widest angle of the plate relative to the rocker shaft closest to the intersecting the rocker shaft while the latches positions, for example, in two drive modes DM1 , and DM 2, which may be associated with the angle of the tangent lines less likely to intersect the rocker shaft. The tangential angle may be any nonperpendicular angle sufficing the tangential angle between 91 degrees to 135 degrees. The reaction forces may lock the components and pieces together while transferring load between the two arms.

[53] FIG. 10 illustrates an example related to the movement of the cam side rocker arm 1004 independently of the valve side rocker arm 1002, according to particular embodiments. FIG. 10 shows the lift profile or lost motion in the CDA mode, rotating the cam side rocker arm 1004 independently of the valve side rocker arm 1002. The rocker arm assembly 1000 may achieve different lost motions including, but not limited to, full lift, partial lift, intermediate lift mode, and no-lift (zero lift) or any other lift height or lift profile or lost motion and different latched conditions or latch steps. In an embodiment, integrating the latch system in the rocker arm assembly 1000 enables the latch system to act as a load transfer component between cam stems and valve stems.

[54] Embodiments disclose rocker arm assemblies to switch between variable valve actuation modes, The activation and deactivation modes for the valve lift and cylinder deactivation respectively may be attained, lower component counts and low-cost latch assembly and rocker arm assembly. The latch system assembly provides a self-retained biasing system and wider tolerances between the components of the rocker arm assembly overcoming the drawbacks of the existing systems. The plate, the spring, and the movable pistons together balance light weighting and desired wide tolerances of the contact points of the cam side and the valve side. The latch system assembly prevents overloading the engine system both mechanically and thermally along with achieving quiet operation.

[55] Herein, “or” is inclusive and not exclusive, unless expressly indicated otherwise or indicated otherwise by context. Therefore, herein, “A or B” means “A, B, or both,” unless expressly indicated otherwise or indicated otherwise by context. Moreover, “and” is both joint and several, unless expressly indicated otherwise or indicated otherwise by context. Therefore, herein, “A and B” means “A and B, jointly or severally,” unless expressly indicated otherwise or indicated otherwise by context.

[56] The scope of this disclosure encompasses all changes, substitutions, variations, alterations, and modifications to the example embodiments described or illustrated herein that a person having ordinary skill in the art would comprehend. The scope of this disclosure is not limited to the example embodiments described or illustrated herein. Moreover, although this disclosure describes and illustrates respective embodiments herein as including particular components, elements, feature, functions, operations, or steps, any of these embodiments may include any combination or permutation of any of the components, elements, features, functions, operations, or steps described or illustrated anywhere herein that a person having ordinary skill in the art would comprehend. Furthermore, reference in the appended claims to an apparatus or system or a component of an apparatus or system being adapted to, arranged to, capable of, configured to, enabled to, operable to, or operative to perform a particular function encompasses that apparatus, system, component, whether or not it or that particular function is activated, turned on, or unlocked, as long as that apparatus, system, or component is so adapted, arranged, capable, configured, enabled, operable, or operative. Additionally, although this disclosure describes or illustrates particular embodiments as providing particular advantages, particular embodiments may provide none, some, or all of these advantages.