System for synchronous switching

Abstract

In one embodiment, a system for synchronized switching includes a first body coupled to a pressurized fluid supply and a control fluid supply, and a second body including a spool valve configured to be housed within a spool valve housing and movable between an open position and a closed position, a biasing element configured to bias the spool valve, and at least three fluid passages configured to be fluidly connected to the spool valve housing. The first body and the second body are configured for movement relative to one another. The spool valve is further configured to selectively control fluid communication between the fluid passages based on relative movement between the first body and the second body.

Description

[0001] CITATION OF RELATED APPLICATION

[0002] The present disclosure is based on and claims the benefit of U.S. Provisional Application No. 63 / 327,849, filed April 6, 2023, which is incorporated by reference herein in its entirety. TECHNICAL FIELD

[0003] The present disclosure relates generally to valve actuation systems, and more particularly to a system for synchronized switching of a switching mechanism used in a valve train assembly. BACKGROUND

[0004] To switch the mode of a valve train of an internal combustion engine, various switching mechanism designs have been created in the past. Because such switching mechanisms are typically located in the middle of the kinematic chain from a rotating camshaft to one or more engine valves, and thus are subjected to considerable system loads, it is crucial to control the timing of the switch so that the switch can only occur when the cam is in a precise angular position. Generally, a control system is typically employed to synchronize the switch. However, such control systems tend to involve complex control logic and computer software, as such control systems must deal with a large number of engine parameters to determine the precise timing.

[0005] Therefore, there is a need to implement a system for synchronized switching that eliminates or at least reduces such complexity while ensuring proper synchronization of the switching mechanism. SUMMARY

[0006] The present disclosure proposes a system for synchronized switching that helps to simplify the control of the switching mechanism by employing a spool that can selectively open and / or close fluid communication between different flow passages to the switching mechanism depending on the position of the rocker arm. So configured, the precise timing of the control system is no longer required. At the same time, the longest time available to the switching mechanism is realized so that the switching mechanism can be fully deployed into place.

[0007] In one embodiment, a system for synchronous switching is provided, the system for synchronous switching comprising: a first body coupled to a pressurized fluid supply and a control fluid supply; and a second body comprising: a spool configured to be housed within a spool housing and movable between an open position and a closed position, a biasing element configured to bias the spool, and a plurality of fluid passages configured to be fluidly connected to the spool housing. The plurality of fluid passages comprises at least a first fluid passage, a second fluid passage, and a third fluid passage. In particular, the first body and the second body are configured for relative movement with respect to each other between a first relative position and a second relative position. When the first body and the second body are in the first relative position, the first fluid passage is in fluid communication with the pressurized fluid supply. When the first body and the second body are in the second relative position, the second fluid passage is in fluid communication with the control fluid supply. Further, the spool is further configured to selectively control fluid communication between the third fluid passage and other fluid passages based on the relative movement between the first body and the second body.

[0008] In particular embodiments, the pressurized fluid supply is an engine pump. In particular embodiments, the control fluid supply is an oil control valve configured to selectively supply control fluid as needed. In particular embodiments, the third fluid passage is configured to be fluidly coupled with a switching mechanism.

[0009] In particular embodiments, fluid flowing from the control fluid supply into the spool housing via the second fluid passage is capable of driving the spool to the open position. In particular embodiments, when the spool is in the open position, fluid flowing from the pressurized fluid supply via the first fluid passage is allowed to flow through the spool housing into the third fluid passage. In particular embodiments, when the spool is in the open position, fluid flowing from the control fluid supply via the second fluid passage is allowed to flow through the spool housing into the third fluid passage. In particular embodiments, fluid flowing from the pressurized fluid supply via the first fluid passage is capable of maintaining the spool in the open position.

[0010] In particular embodiments, the biasing element is configured to bias the spool towards the closed position. In particular embodiments, when the spool is in the closed position, fluid communication through the spool housing to the third fluid passage is disabled.

[0011] In particular embodiments, the plurality of fluid passages further comprises a fourth fluid passage configured to vent fluid housed within the spool housing when the spool is in the closed position. In particular embodiments, when the spool is in the open position, the spool blocks fluid communication to the fourth fluid passage. In particular embodiments, when the spool is in the open position, fluid flowing from the second fluid passage is blocked from entering the third fluid passage.

[0012] In particular embodiments, the biasing element is a spring. In particular embodiments, the relative movement between the first body and the second body is caused by rotation of the rocker arm. In particular embodiments, fluid communication between the first fluid passage and the pressurized fluid supply is available when the rocker arm is in the base circle position, and fluid communication between the second fluid passage and the control fluid supply is available when the rocker arm is near the maximum lift position. In particular embodiments, fluid communication from the pressurized fluid supply through the first fluid passage and the spool valve housing to the third fluid passage is available when the rocker arm is in the base circle position. BRIEF DESCRIPTION OF DRAWINGS

[0013] Embodiments in accordance with the present disclosure will now be described with reference to the accompanying drawings, in which:

[0014] Figure 1 is a schematic depiction of an exemplary rocker assembly incorporating an embodiment of a system for synchronized switching in accordance with the present disclosure, wherein the system is shown in two different cross-sectional views;

[0015] Figure 2 a series of schematic depictions of the system for synchronized switching of Figure 1 is shown during operation as the oil control valve transitions from closed to open;

[0016] Figure 3 a series of schematic depictions of the system for synchronized switching of Figure 1 is shown during operation as the oil control valve transitions from open to closed;

[0017] Figure 4 is a schematic depiction of another embodiment of a system for synchronized switching in accordance with the present disclosure, wherein the system is shown in two different cross-sectional views; and

[0018] Figure 5 is a schematic depiction of another embodiment of a system for synchronized switching in accordance with the present disclosure for use in conjunction with a lost motion shaft. DETAILED DESCRIPTION

[0019] Reference will now be made in detail to instances of the subject matter which are illustrated in the accompanying drawings. Wherever possible, the same reference numbers will be used throughout the drawings to refer to the same or like parts. Directional references such as "upper," "lower," "right," and "left" are made for ease of reference to the drawings and are not intended to limit the scope of the disclosure.

[0020] Figure 1An embodiment of a system for synchronized switching according to the present disclosure is shown, wherein the system can be provided in an exemplary rocker assembly comprising a rocker arm 6 and a rocker shaft 7 that pivotally supports the rocker arm 6. In certain applications, the rocker assembly can be used to actuate engine valves in a multi-cylinder engine configured with a cylinder deactivation function, i.e., one or more valves associated with a selected cylinder combination can be deactivated for the purpose of adjusting engine and / or fuel efficiency as needed. In this case, to provide selective deactivation on demand, a switching mechanism (not shown) is typically employed that can be coupled to the rocker arm 6 or otherwise incorporated with the rocker assembly, for example.

[0021] By way of example and not limitation, the switching mechanism can generally be configured for selectively displacing its associated movable component between a locked position for enabling a primary lift event of the valve and an unlocked position for deactivating valve actuation under the control of a force source. In practice, during periods of rocker arm rotation, i.e., during a lift event, the switching mechanism can be subjected to considerable system loads as it transmits actuation motion from the camshaft to the associated engine valve. In this case, such loads on the switching mechanism can create very high frictional forces such that no matter how much control force (if any) is applied to the switching mechanism, it cannot be moved. During periods of non-rotation of the rocker arm, such as when the rocker arm is in contact with the base circle of the camshaft and receives zero lift, the loads applied to the switching mechanism are correspondingly removed, thereby releasing the switching mechanism to allow it to switch between the locked and unlocked positions. Ideally, it can be desirable to control the movement of the switching mechanism such that the switching process can advantageously begin immediately after completion of the valve lift to maximize the time available for switching.

[0022] To enable conventional systems to achieve this maximization, the electronic signals to the control system must be precisely synchronized to control switching only at the beginning of the base circle. However, determining the exact timing of when to switch is particularly challenging as it requires a complex matrix of various operating parameters such as engine speed, oil pressure, oil temperature, etc. In contrast to prior art solutions, the system for synchronized switching according to the present disclosure can achieve the maximization of switching time in a much simpler manner. Moreover, even if the control system for enabling the switching mechanism is not precisely synchronized, the system of the present disclosure can guarantee correct switching, thereby significantly reducing the complexity of the control scheme required to implement the switching process. This can also help to reduce the likelihood of partial locking or partial engagement of the switching mechanism that can cause severe displacement, as the switching mechanism will have sufficient time at its disposal to fully complete its travel to be positioned in full engagement.

[0023] Exemplary configurations of switching mechanisms that can be used in conjunction with the system for synchronized switching of the present disclosure can include, but are not limited to, deactivation rollers, split-body rocker levers, switchable lifters, switchable castellations, and the like, to name a few. Although described in the context of such switching mechanisms, those skilled in the art will recognize that the system for synchronized switching according to the present disclosure can be equally applicable and beneficial to other suitable configurations for valve actuation systems, including those using mechanical locking as well as hydraulic locking, and the like.

[0024] In particular embodiments, the system for synchronization can include a first body and a second body configured for movement relative to one another such that the first body and the second body can move from a first relative position to a second relative position, and vice versa. As a non-limiting example, as shown in Figure 1 the first body can be formed inside a rocker shaft 7, while the second body can be disposed within a rocker arm body 6 such that the second body can move relative to the first body when the rocker arm body 6 is pivoted about the rocker shaft 7. While depicted in this manner, the positions of the first body and the second body are not limited thereto. As will be recognized by those skilled in the art upon reading the detailed description, drawings, and claims disclosed herein, other suitable movable components in a valve train assembly can also be adapted to the system of the present disclosure as needed.

[0025] In Figure 1 the embodiment shown, the first body can include a first fluid passage 4 connected to a main fluid circuit, which can be configured for receiving pressurized fluid (e.g., oil) from an engine pump or from other suitable pressurized fluid source well known to those skilled in the art. The first body can also include a second fluid passage 5, which can be used as, for example, a control gallery fluidly connected to an oil control valve (OCV). The oil control valve can be used as a separate oil supply that is independent of the example engine pump and can be opened and / or closed as needed. In the embodiment as shown, the first fluid passage 4 and the second fluid passage 5 can be routed from their respective fluid supply sources (i.e., the example engine pump and the example oil control valve) to an interface between the rocker shaft 7 and the rocker arm body 6. In this manner, the extent to which the rocker arm body 6 is rotated about the rocker shaft 7 into position can allow fluid to communicate from either of the first fluid passage 4 and the second fluid passage 5 to the rocker arm body 6 via the interface, and specifically to the second body of the system for synchronization disposed inside the rocker arm body 6.

[0026] As Figure 1As shown, the second body can include a spool valve 2 housed by a spool valve housing, a spring 8 coupled to a bottom of the spool valve 2 and configured to bias the spool valve 2, and a plurality of fluid passages, such as a third fluid passage 9, a fourth fluid passage 3, and a fifth fluid passage 1, can be respectively ported to the spool valve housing, thereby providing flow access to the spool valve 2. The spool valve 2 can be configured to be selectively translatable within the spool valve housing along an axial direction between an open position and a closed position. For example, the spool valve 2 can be driven to the open position by a hydraulic control force provided by the example oil control valve, or to the closed position under a biasing force of the spring 8. Of course, other suitable biasing elements can similarly be employed in place of the spring 8 to urge the spool valve 2 back to its default position, as would be known to those skilled in the art.

[0027] As further shown, one end of the third fluid passage 9 can be positioned at an interface between the rocker arm body 6 and the rocker shaft 7, while the other end of the third fluid passage can be positioned on a circumferential side wall of the spool valve housing and adjacent to a head of the spool valve 2. Further, one end of the fourth fluid passage 3 can also be positioned at the interface between the rocker arm body 6 and the rocker shaft 7, while the other end of the fourth fluid passage can be connected to the spool valve housing proximate to an axial end of the third fluid passage 9. In particular, the third fluid passage 9 and the fourth fluid passage 3 can be ported at such a position at the interface that when the rocker arm body 6 is on the base circle, the first fluid passage 4 can be in fluid connection with the third fluid passage 9, and when the rocker arm body 6 is rotated to a certain predetermined angular position (e.g., a maximum lift position) relative to the rocker shaft 7, the second fluid passage 5 can be in fluid connection with the fourth fluid passage 3. Further, at the circumferential side wall of the spool valve housing, the fifth fluid passage 1 can be opened at a position generally opposite the third fluid passage 9 in a radial direction. The fifth fluid passage 1 can be configured to fluidically connect the spool valve housing to a downstream switching mechanism (not shown) associated with the rocker arm body 6 to charge the switching mechanism with fluid as needed.

[0028] Referring now to Figures 2-3 , the operation of the system for synchronized switching is described, wherein Figure 2 Particularly shown are the relative positions of the first body and the second body of the system for synchronized switching when the example oil control valve is transitioning from closed to open, and Figure 3 Particularly shown are the relative positions of the first body and the second body of the system for synchronized switching when the example oil control valve is transitioning from open to closed.

[0029] In Figure 2In the middle, in step 201, the rocker arm body 6 is shown in the base circle position, where the rocker arm body 6 does not receive lift from the camshaft and the associated valve is thus closed. In this operating position, in the specific embodiment, the first body and the second body of the system for synchronous switching are in their first relative position, where the first fluid passage 4 is allowed to be in fluid connection with the third fluid passage 9, so that the system is in communication with the exemplary engine pump supplying pressurized fluid. At the same time, in this first relative position between the first body and the second body, the fourth fluid passage 3 is rotated to its angle of dislocation from the second fluid passage 5. Thus, when the exemplary oil control valve is opened as required, although control fluid from the exemplary oil control valve can fill the second fluid passage 5, due to this misalignment of the fourth fluid passage 3 from the second fluid passage 5, the control fluid cannot reach the spool valve 2. Without any hydraulic pressure driving the spool valve 2, the spool valve 2 remains in the default closed position under the biasing spring force (more clearly observed in the right cross-sectional view at 201). Accordingly, the cross-communication between the third fluid passage 9, the fourth fluid passage 3, and the fifth fluid passage 1 is sealed by the spool valve 2, thereby preventing pressurized fluid and control fluid from reaching the switching mechanism located downstream. In this case, the switching mechanism remains unlocked.

[0030] Then, in step 202, after the rocker arm body 6 receives lift from the camshaft and rotates to an angle of a predetermined angular position as shown, for example, advantageously near the maximum lift, in this case, the first body and the second body of the system for synchronous switching are in the second relative position, in the specific embodiment, the first fluid passage 4 can be disconnected from the third fluid passage 9, while the second fluid passage 5 can be fluidly connected with the fourth fluid passage 3 instead. Thereby, the fluid that has filled the second fluid passage 5 is allowed to enter the fourth fluid passage 3 and reach the spool valve housing. As a result, the resulting hydraulic pressure can act axially on the spool valve 2, pushing the spool valve 2 to the open position against the spring 8, so that the inlet of the fifth fluid passage 1 is exposed. In this way, fluid communication with the switching mechanism is available, and the switching mechanism can be preloaded with fluid supplied from the exemplary oil control valve. It should be noted that although the switching mechanism is now preloaded, it still remains unlocked, at least because the fluid pressure provided by the exemplary oil control valve is not sufficient to overcome the significant mechanical load acting on the switching mechanism during valve lift.

[0031] In step 203, the rocker arm body 6 rotates back onto the base circle. Correspondingly, the first and second bodies return to their first relative position at which the first fluid passage 4 is re-coupled with the third fluid passage 9, while the fluid connection between the second fluid passage 5 and the fourth fluid passage 3 is again interrupted due to their misalignment. In this position, the control fluid from the example oil control valve no longer reaches the spool valve 2, however the spool valve 2 is held in the open position by the pressurized fluid supplied from the example engine pump, in such a way that the flow communication to the switching mechanism via the fifth fluid passage 1 is maintained. Because the fifth fluid passage 1 is already preloaded with control fluid from the example oil control valve at this time, an increase in fluid pressure provided by the example engine pump can be quickly transmitted to the switching mechanism. In this way, it can be ensured that the switching mechanism can be immediately pressurized by the fluid supplied from the example engine pump as soon as the rocker arm body 6 is fully back onto the base circle.

[0032] Configured in this way, the system for synchronized switching according to the present disclosure can advantageously maximize the time available for switching by ensuring that the actuation of the switching mechanism can be initiated immediately as soon as the valve lift is completed. Moreover, by controlling the synchronization to occur in this essentially mechanical and automatic way, the system for synchronized switching of the present disclosure can eliminate the need for precise timing of the example oil control (which would otherwise be required for conventional control systems for performing switching operations via electronic means), thereby reducing the complexity of the overall system to a significant extent. Furthermore, it can also help to prevent critical shifts, as the switching mechanism will have the longest time available for fully engaging to its locked position.

[0033] The technical advantages explained above are by way of example only and not limitation. Certain embodiments disclosed herein can not provide all of the technical advantages discussed above, or can provide some, all, or none of such technical advantages. One or more other technical advantages can be readily apparent to one skilled in the art in view of the figures, descriptions and claims included herein.

[0034] Turning now to Figure 3 , a system for synchronized switching is described during operation when the example oil control valve is transitioning from open to closed. In step 301, the rocker arm body 6 is in contact with the base circle of the camshaft and the first and second bodies of the system for synchronized switching are in their first relative position at which fluid communication with the example engine pump is available and the flow path from the example oil control valve is disconnected. Despite the oil control valve being closed and stopping oil injection to the second fluid passage 5, the spool valve 2 is held in its open position under the fluid pressure provided by the example engine pump. Therefore, fluid communication to the switching mechanism via the fifth fluid passage 1 is still available, keeping the switching mechanism firmly locked.

[0035] When the rocker arm body 6 is rotated to the angular position shown in step 302, the fluid connection from the exemplary engine pump is interrupted as the third fluid passage 9 moves out of alignment with the first fluid circuit 4. In this case, the hydraulic pressure pushing the spool valve 2 against the spring 8 is removed, so the spool valve 2 is pushed back to its default closed position by the biasing spring force, at which point the passage through the fifth fluid passage 1 to the switching mechanism is disabled. However, in this case, even though no fluid can reach the switching mechanism, the switching mechanism remains in its locked configuration due to the mechanical load of the engine valve and other moving transfer components of the valve train assembly that are applied to the switching mechanism during the lift event.

[0036] Finally, in step 303, once the rocker arm body 6 is rotated back onto the base circle to close the valve, removing the system load on the switching mechanism, the switching mechanism will immediately shift back to its original unlocked position.

[0037] It should be noted that, in the exemplary embodiment as depicted in Figure 2 and Figure 3 , the pressurized fluid supply from the exemplary engine pump can be continuously kept open throughout the entire operating cycle of the rocker assembly, for example, both during the rotation of the rocker arm body 6 and when the rocker arm body 6 is in the base circle position, while on the other hand, the exemplary oil control valve can be selectively opened and / or closed at any time as needed during the base circle. It should be appreciated that by implementing in this way, the precision requirements for the timing of the activation of the oil control valve are lower, thus simplifying the synchronization of the system.

[0038] Figure 4 Another possible embodiment of a system for synchronized switching according to the present disclosure is shown. As a non-limiting example, similar to the reference Figures 1-3The described system for synchronized switching can likewise include a first body and a second body configured for movement relative to one another such that the first body and the second body can be moved between a first relative position and a second relative position. In some embodiments, the first body can be formed inside a rocker shaft while the second body can be disposed within a rocker arm body such that the second body can move relative to the first body when the rocker arm body is pivoted about the rocker shaft. Similarly, the first body can be designed to have a main fluid circuit connected to an exemplary engine pump serving as a pressurized fluid supply and a control circuit coupled with an exemplary oil control valve. During operation of the rocker arm, the main fluid circuit or the control circuit is allowed to establish fluid communication with the second body disposed inside the rocker arm. Again, while described in this particular manner, the system for synchronized switching is not limited thereto. Those skilled in the art will appreciate that the system for synchronized switching of the present disclosure can also be used in conjunction with other suitable moving components in a valve train.

[0039] In this embodiment as shown, the system for synchronized switching is provided with a spool valve 402 that can be housed within a spool valve housing 404 and configured to be movable, for example, axially along the spool valve housing 404, between an open position and a closed position. As depicted, the spool valve 402 is designed to have a valve head 408 adapted to receive hydraulic pressure to push the spool valve 402 open, a valve stem 410 connecting the valve head 408 to a main body portion of the spool valve 402, and a valve spring 406 disposed at the bottom of the spool valve 402 that can bias the spool valve 402 to the closed position. Additionally, as shown in this embodiment, an annular space 412 can be formed between the valve stem 410 and the inner wall of the spool valve housing 404 that can be adapted to provide a flow passage for fluid to flow through.

[0040] As further illustrated in this example embodiment, the spool housing 404 can be connected to four respective fluid passages, namely a first fluid passage 414, a second fluid passage 416, a third fluid passage 418, and a fourth fluid passage 420. As depicted, the first fluid passage 414 can be fluidically connected to an axial end of the spool housing 404 proximate to the valve head 408 of the spool valve 402, while the second fluid passage 416, the third fluid passage 418, and the fourth fluid passage 420 can be ported to a circumferential sidewall of the spool housing 404 at a distance relative to one another in the axial direction. In a particular embodiment, the first fluid passage 414 can be used to receive fluid (e.g., oil) from a control circuit connected with the example oil control valve, and release the fluid axially into the spool housing 404 to urge the spool valve 402 to an open position. The second fluid passage 416, shown as being closest to the first fluid passage 414, can be used as a drain passage that provides an exit for fluid contained within an annular space 412 surrounding the valve stem 410 to be drained. The third fluid passage 418 can be in fluid communication with a switching mechanism (not shown) associated with the rocker arm, and configured to supply control fluid to the switching mechanism when a proper flow path through the spool housing 404 has been established (details of which will be explained below). Finally, the fourth fluid passage 420, shown as being farthest from the first fluid passage 414, can be configured to receive pressurized fluid (e.g., oil) from a main fluid circuit in communication with the example engine pump, and to inject the pressurized fluid radially into the spool housing 404. In particular, this pressurized fluid can be used as a fluid that communicates through the third fluid passage 418 to enable locking of the switching mechanism when the spool valve 402 is open.

[0041] The operation of this embodiment of the system for synchronized switching will be described in more detail below. In Figure 4 In the example embodiment of the example oil control valve, during operation, when the example oil control valve is closed, i.e., no fluid is flowing through the first fluid passage 414 to drive the spool valve 402, the spool valve 402 can remain in its closed state under a spring force provided by the valve spring 406. In this position of the spool valve 402, the body portion of the spool valve 402 can be in an axial position that closes the opening to the fourth fluid passage 420, such that pressurized fluid is not allowed to enter the spool housing 404. As a result, pressure communication to the downstream switching mechanism is cut off, causing the switching mechanism to remain unlocked.

[0042] When the example oil control valve is opened and supplies fluid to the spool housing 404 via the first fluid passage 414, which can preferably occur when the rocker arm is rotating near its maximum lift, the supplied fluid can act on the valve head 408 of the spool 402 and push the spool 402 (e.g., to the right as shown) against the biasing spring force to an open position. In this configuration, the opening of the fourth fluid passage 420 on the spool housing 404 can be exposed by the movement of the spool 402, allowing pressurized fluid from the example engine pump to enter the annular space 412 between the valve stem 410 and the inner wall of the spool housing 404. The pressurized fluid can then flow through the annular space 412 into the third flow passage 418 and ultimately to the switching mechanism to pressurize it for movement. It should be noted that in this open position of the spool 402, the flow connection between the annular space around the valve stem and the second fluid passage 416 (i.e., the unloading path) can be substantially closed by the valve head 408, such that the fluid pressure from the fourth fluid passage 420 through the third fluid passage 418 to the switching mechanism is effectively maintained at a desired level to keep the switching mechanism firmly locked in place.

[0043] Thereafter, when it is desired to unlock the switching mechanism, the oil control valve can be closed, and the spool 402 again returns to its default closed state (as Figure 4 depicted) under the biasing force of the valve spring 406. As a result, the pressurized fluid supply from the engine pump via the fourth fluid passage 420 is interrupted or blocked by the return of the spool 402. At the same time, the travel of the spool 402 can be further designed such that the annular space 412 around the valve stem 410 can communicate with the second fluid passage 416, such that the fluid pressure previously charging the switching mechanism can be released as fluid exits the spool housing 404 from the second fluid passage 416. As a result of this reduction in fluid pressure, the switching mechanism is allowed to shift back to its unlocked state due to the fluid pressure.

[0044] Configured in the manner described above with reference to Figure 4 the example oil control valve, an embodiment of the system for synchronized switching can only use the example oil control valve to control the movement of the spool 402 to open or close the access from the fourth fluid passage 420 to the third fluid passage 418 (and accordingly to the switching mechanism). In other words, in this embodiment, the control fluid from the example oil control valve cannot enter the switching mechanism. Additionally, it can be desirable for the opening of the spool 402 to occur when the rocker arm is rotating near its maximum lift position.

[0045] Figure 5Another possible implementation of the system for synchronous switching according to this disclosure is illustrated schematically, which is used in conjunction with a pneumatic shaft, wherein the left depiction shows the rocker arm associated with the pneumatic shaft in the base circle position, while the right depiction shows the rocker arm in the lift position.

[0046] exist Figure 5 In this embodiment, the system for synchronous switching is configured in a manner substantially similar to those described above. This synchronous switching system includes: a spool valve; a first fluid passage configured to receive fluid from an exemplary oil control valve; a second fluid passage configured to receive pressurized fluid from an exemplary engine pump; and a third fluid passage fluidly connected to a switching mechanism (not shown). However, in this embodiment, the system's selective fluid communication with the exemplary oil control valve or exemplary engine pump is controlled via the stroke of the pneumatic shaft. To achieve this configuration, for example, a groove formed on the sidewall surface of the pneumatic shaft can be used to receive fluid from the exemplary oil control valve or exemplary engine pump. For example, when the pneumatic shaft extends—that is, when the rocker arm is on the base circle—the groove moves to engage with the second fluid passage, allowing pressurized fluid supplied by the exemplary engine pump to flow through the annular gap into the second fluid passage, and functioning similarly to the above-mentioned reference. Figure 2 Similar effects are described (e.g., specifically in steps 201 or 203). Alternatively, when the idler shaft retracts to complete its full stroke, the groove can, for example, be vertically upward as depicted, to connect with a first fluid passage receiving control fluid from an exemplary oil control valve. When this occurs, the control fluid can push the spool valve to the open position and optionally further fill a third fluid passage to preload a downstream switching mechanism. Other suitable modifications and variations may be employed for the purpose of performing the intended functions of this disclosure and will not be described exhaustively to avoid obscuring the scope of this disclosure.

[0047] In this document, unless otherwise expressly indicated or the context otherwise indicates, “or” is inclusive rather than exclusive. Therefore, in this document, unless otherwise expressly indicated or the context otherwise indicates, “A or B” means “A, B, or both.” Furthermore, unless otherwise expressly indicated or the context otherwise indicates, “and” is both common and separate. Therefore, in this document, unless otherwise expressly indicated or the context otherwise indicates, “A and B” means “A and B, commonly or separately.”

[0048] The scope of the 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 the disclosure is not limited to the example embodiments described or illustrated herein. Moreover, although the disclosure describes and illustrates respective embodiments herein as comprising specific components, elements, features, functions, operations or steps, any of the embodiments can 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. Moreover, references to devices or systems or components thereof, in the appended claims are meant to encompass devices, systems, or components that are adapted in, arranged in, capable of, configured for, operable to, or operative to perform the particular functions where the same are framed in the language of adaptations, arrangements, capabilities, configurations, operability, or operatives. Further, although the disclosure describes or illustrates particular embodiments as providing particular advantages, such embodiments can not offer any particular advantage or offer some or all of the advantages described.

Claims

1. A system for synchronous switching, comprising: a first body coupled to a pressurized fluid supply and a control fluid supply; and a second body comprising: a spool configured to slide within a spool housing to switch between an open position and a closed position, a biasing element configured to bias the spool, and a plurality of fluid passages configured to be fluidly connected to the spool housing, the plurality of fluid passages comprising a first fluid passage, a second fluid passage, and a third fluid passage; wherein the first body and the second body are configured to move relative to each other between a first relative position and a second relative position, the first fluid passage is in fluid communication with the pressurized fluid supply when the first body and the second body are in the first relative position, and the second fluid passage is in fluid communication with the control fluid supply when the first body and the second body are in the second relative position; wherein the spool is further configured to selectively control fluid communication between the third fluid passage and the first fluid passage or the second fluid passage based on relative movement between the first body and the second body; and wherein, when the spool is in the open position, fluid flowing from the control fluid supply via the second fluid passage flows through the spool housing into the third fluid passage. The pressurized fluid supply is an engine pump.

2. The system of claim 1, wherein, The control fluid supply is an oil control valve configured to selectively supply control fluid.

3. The system of claim 1, wherein, The third fluid passage is configured to be fluidly coupled with a switching mechanism.

4. The system of claim 1, wherein, Fluid flowing from the control fluid supply into the spool housing via the second fluid passage drives the spool to the open position.

5. The system of claim 1, wherein, When the spool is in the open position, fluid flowing from the pressurized fluid supply via the first fluid passage flows through the spool housing into the third fluid passage.

6. The system of claim 1, wherein, When the spool is in the open position, fluid flowing from the pressurized fluid supply via the first fluid passage flows into the spool housing to maintain the spool in the open position.

7. The system of claim 1, wherein, The biasing element is configured to bias the spool toward the closed position.

8. The system of claim 1, wherein, When the spool is in the closed position, fluid communication through the spool housing to the third fluid passage is disabled.

9. The system of claim 1, wherein, The biasing element is a spring.

10. The system of claim 1, wherein, Relative movement between the first body and the second body is caused by rotation of a rocker arm.

11. The system of claim 1, wherein, When the rocker arm is in a base circle position, fluid communication between the first fluid passage and the pressurized fluid supply is available, and when the rocker arm is in a maximum lift position, fluid communication between the second fluid passage and the control fluid supply is available.

12. The system of claim 11, wherein, When the spool is in the open position, fluid flowing from the pressurized fluid supply via the first fluid passage is able to pass through the spool housing into the third fluid passage when the rocker arm is in the base circle position.

13. The system of claim 12, wherein, 14. A system for synchronous switching, comprising: ​ a spool valve configured to slide within a spool valve housing to switch between an open position and a closed position, a biasing element that biases the spool valve toward the closed position, and a plurality of fluid passages fluidically connected to the spool valve housing, the plurality of fluid passages including a first fluid passage, a second fluid passage, a third fluid passage, and a fourth fluid passage; wherein the first fluid passage is configured to receive fluid from a control fluid supply, the second fluid passage is configured to receive fluid from a pressurized fluid supply, the third fluid passage is connected with a switching mechanism of a rocker arm, and the fourth fluid passage is positioned between the first fluid passage and the second fluid passage to vent fluid contained within the spool valve housing when the spool valve is in the closed position; wherein the spool valve is switched to the open position via fluid from the first fluid passage; and wherein, when in the open position, the spool valve opens fluid communication from the second fluid passage to the third fluid passage to actuate the switching mechanism.

15. A system for synchronized switching, comprising: a lost motion shaft fluidically coupled to a pressurized fluid supply and a control fluid supply; a spool valve configured to slide within a spool valve housing to switch between an open position and a closed position, a biasing element that biases the spool valve toward the closed position, and a plurality of fluid passages fluidically connected to the spool valve housing, the plurality of fluid passages including a first fluid passage, a second fluid passage, and a third fluid passage; wherein the lost motion shaft is configured to move between (i) a retracted position that opens fluid communication from the control fluid supply to the first fluid passage and (ii) an extended position that opens fluid communication from the pressurized fluid supply to the second fluid passage; and wherein the spool valve selectively switches between the open position and the closed position to control fluid communication between the third fluid passage and the first fluid passage or the second fluid passage.

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