Ventilbrücke

Abstract

A valve bridge for a rocker arm assembly is provided, including a first end, a second end, and a top surface of a bridge body portion connecting the first and second ends. The top surface is configured to engage a first rocker arm. A recess is located at an upper surface of the first end. The recess has a shape that is at least partially an ogive and is configured to engage a second rocker arm. A first valve seat is disposed at a lower surface of the first end and has a curved bottom surface for engaging a first valve. A second valve seat is disposed at a lower surface of the second end for engaging a second valve.

Description

CROSS-REFERENCE TO RELATED APPLICATION

[0001] This disclosure is based upon and claims the benefit of U.S. Provisional Patent Application No. 63 / 382,470, entitled “Valve Bridge for Engine Braking,” filed November 4, 2022, which is incorporated herein by reference in its entirety. TECHNICAL FIELD

[0002] This disclosure relates generally to a valve train system and, more particularly, to a valve bridge for use with a rocker arm assembly configured with an engine braking function. BACKGROUND

[0003] Internal combustion engines typically use either a mechanical, electrical, or hydromechanical valve actuation system to operate the engine valves. These systems may include a combination of camshafts, rocker arms, and various motion-transmitting mechanisms driven by the engine's crankshaft rotation. The timing of valve actuation can be determined by the size and location of the cam lobes on the camshaft, the configuration of the rocker arms, etc. SUMMARY OF SPECIAL EMBODIMENTS

[0004] This disclosure provides a valve bridge for use in a rocker arm system capable of individually actuating a selected valve, i.e., the selected valve is actuated while another valve remains unaffected. By using uniquely shaped components for engagement with the rocker arms and the engine valves, the valve bridge according to this disclosure provides better motion and force transmission, ensures more reliable contact and engagement, and optimizes the overall kinematic behavior of the system. For example, the contact surfaces of the valve bridge with the rocker arm and the engine valve, respectively, are designed to be more ergonomic and streamlined, resulting in lower contact stress and friction. In addition, the structure of the valve bridge has been simplified, making operation and the production process simpler and more cost-effective.

[0005] In one embodiment, a valve bridge for a rocker arm assembly is provided. The valve bridge includes a first end, a second end opposite the first end, and an upper surface of a bridge body portion connecting the first and second ends. The upper surface of the bridge body portion is configured to engage a first rocker arm. A first recess is located at the top of the first end. The first recess has a shape that is at least partially an ogive and is configured to engage a second rocker arm. A first valve seat is disposed at a bottom of the first end and has a curved bottom surface for engaging a first valve. A second valve seat is disposed at the bottom of the second end to actuate a second valve.In particular, the valve bridge is configured to translate vertically upon actuation by the first rocker arm to actuate both the first and second valves, or to tilt angularly upon actuation by the second rocker arm to actuate the first valve without actuating the second valve.

[0006] In particular embodiments, the engagement between the first recess and the second rocker arm forms a circular contact line. In particular embodiments, the first valve seat is a channel. In particular embodiments, the curved bottom surface of the first valve seat is S-shaped. In particular embodiments, the curved bottom surface of the first valve seat enables lateral displacement of the first valve relative to the valve bridge. In particular embodiments, the second valve seat comprises a second recess. In particular embodiments, an inner diameter of the second valve seat is larger than an outer diameter of a port of the second valve. In particular, the second end comprises a horizontal through-hole and a kinematic cylinder rotatably inserted into the horizontal through-hole.In particular embodiments, the kinematic cylinder engages the second valve and maintains surface contact with the second valve as the valve bridge tilts. In certain embodiments, the upper surface includes a guide for controlling the movement of the valve bridge relative to the first rocker arm.

[0007] In one embodiment, a valve bridge for a rocker arm assembly is provided. The valve bridge includes a first end, a second end opposite the first end, and an upper surface of a bridge body portion connecting the first and second ends. The upper surface of the bridge body portion is configured to engage a first rocker arm. A projection is disposed on an upper surface of the first end and has an ogive shape at the upper end of the projection for engaging a second rocker arm. A first valve seat is disposed on the underside of the first end and has a curved bottom surface for engaging a first valve. A second valve seat is disposed on the underside of the second end for actuating a second valve.In particular, the valve bridge is configured to translate vertically upon actuation by the first rocker arm to actuate both the first and second valves, or to tilt angularly upon actuation by the second rocker arm to actuate the first valve without actuating the second valve.

[0008] In particular embodiments, the engagement between the projection and the second rocker arm forms a circular contact line. In certain embodiments, the projection is removably received in a recess located at the top of the first end. In particular embodiments, the curved bottom surface of the first valve seat is S-shaped. In certain embodiments, the curved bottom surface of the first valve seat allows for lateral displacement of the first valve relative to the valve bridge.

[0009] In one embodiment, a rocker arm assembly is provided that includes a first rocker arm and a second rocker arm, a first valve and a second valve, and a valve bridge configured to be selectively actuated by one of the first rocker arm and the second rocker arm. The valve bridge includes a first end, a second end opposite the first end, and an upper surface of a bridge body portion connecting the first and second ends. The upper surface of the bridge body portion is configured to engage the first rocker arm. A recess is located at a top surface of the first end. The recess has a shape that is at least partially an ogive and is configured to engage a spherical end of the second rocker arm.The first valve seat is disposed on a bottom surface of the first end and has a curved bottom surface for engaging the first valve. A second valve seat is disposed on the bottom surface of the second end to actuate the second valve. Specifically, the valve bridge is configured to translate vertically upon actuation by the first rocker arm to actuate both the first and second valves, or to tilt angularly upon actuation by the second rocker arm to actuate the first valve without actuating the second valve.

[0010] In particular embodiments, the first rocker arm is an exhaust rocker arm and the second rocker arm is an engine brake rocker arm. In particular embodiments, the engagement between the recess and the spherical end of the second rocker arm forms a circular contact line. In particular embodiments, the second end comprises a horizontal through-hole and a kinematic cylinder rotatably inserted into the horizontal through-hole. In particular embodiments, the upper surface comprises a guide for guiding the movement of the valve bridge relative to the first rocker arm. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Embodiments according to this disclosure will now be described with reference to the accompanying drawings, in which: The Fig. 1A-1B show various examples of a valve train assembly according to this disclosure; Fig. 2 shows a first embodiment of a valve bridge for use in a rocker arm assembly according to this disclosure; The Fig. 3A-3B show perspective views of the valve bridge of Fig. 2 from top; The Fig. 4A-4B show perspective views of the valve bridge of Fig. 2 from the bottom; The Fig. 5A-5B show the valve bridge in operation when the rocker arm assembly is in drive mode; The Fig. 6A-6B illustrate the valve bridge in operation when the rocker arm assembly is in engine braking mode; The Fig. 7-8 illustrate a second embodiment of a valve bridge for use in a rocker arm assembly according to this disclosure; The Fig. 9-10 illustrate a third embodiment of a valve bridge for use in a rocker arm assembly according to this disclosure; and The Fig. 11-12 illustrate a fourth embodiment of a valve bridge for use in a rocker arm assembly according to this disclosure. DESCRIPTION OF EMBODIMENTS

[0012] Reference will now be made in detail to the examples illustrated in the accompanying drawings. Wherever possible, the same reference numerals will be used throughout the drawings to refer to the same or similar parts. Directional references such as "top," "bottom," "right," and "left" are provided for convenience in referring to the figures and are not intended to limit the scope of the present disclosure.

[0013] Valve bridges can connect the rocker arms and the engine valves in such a way that the rotation of the rocker arms is converted into movement of the valves to open the valves in a controlled manner. There is a need to optimize the design of valve bridges to better control valve actuation with reliable yet simplified structures. In the past, various valve systems for internal combustion engines have been developed to control the actuation of valves, e.g., for the main exhaust. Generally, in a typical valve train, a rocker arm system is coupled to a camshaft on one side and to a bank of engine valves via a valve bridge on the other side to synchronously transmit the actuating movement from the camshaft to the downstream valves. In some scenarios, it may be desirable to have an auxiliary function, such as a cam follower, in addition to the main lift process.The purpose of the valve bridge is to provide a motion control mechanism for the compression engine, i.e., braking the compression engine, so that a selected valve can be controlled separately. To achieve this, a switchable system is often used that can be selectively moved between a retracted and an extended position, with the retracted position disabling actuation of the associated valve by a corresponding rocker arm, and the extended position enabling actuation of the valve. Accordingly, the valve bridge can also be equipped with a motion transmission mechanism that serves to actuate the selected valve independently without affecting the others. However, current designs typically use complex moving components (e.g., a sliding component that moves up and down within the valve bridge), which leads to force balancing problems, requires relatively large installation space, and increases production and material costs.Consequently, there is a need for a solution that is cost-effective, easy to manufacture and use, and also offers the desired system dynamics.

[0014] The embodiments disclosed herein present a valve bridge that solves the above-mentioned problems by being able to rotate on demand, thus actuating the selected valve while leaving the other valve unaffected. By utilizing uniquely shaped components for engagement with the rocker arms and engine valves, the valve bridge according to this disclosure provides better motion and force transmission, ensures more reliable contact and engagement, and optimizes the overall kinematic behavior of the system. Furthermore, the structure of the valve bridge is simplified, resulting in lower manufacturing costs and enabling ease of operation.

[0015] With initial reference to the Fig. 1A-1B, a valvetrain assembly constructed in accordance with an example of the present disclosure is partially illustrated and generally designated by the reference numeral 10. In certain embodiments, the valvetrain assembly 10 may be configured with additional functionality, such as engine braking, and is illustrated for use in an inline three-cylinder section of a six-cylinder engine. Although described as such, the present disclosure is not so limited. In this regard, the present disclosure may be used in any valvetrain assembly having additional functionality.

[0016] In particular embodiments, the valvetrain assembly 10 may be supported by a valvetrain carrier 12 and may include two rocker arms per cylinder. Specifically, in certain embodiments, each cylinder may include an intake rocker arm assembly 14, an exhaust rocker arm assembly 16, and an engine brake rocker arm assembly 18. As shown in Fig. For example, as shown in Figure 1A, the exhaust rocker arm assembly 16 and the engine braking rocker arm assembly 18 may be combined into a single rocker arm body and are collectively referred to as a combined exhaust and engine braking rocker arm assembly 20, which cooperates to control the opening or closing of the exhaust valves. In this case, two switchable systems (e.g., capsules or the like) may be used to separately control exhaust and engine braking operation. As a further example and without limitation, as shown in Fig. 1B, the exhaust rocker arm assembly 16 and the engine brake rocker arm assembly 18 may be separate assemblies and act independently on a valve bridge. In certain embodiments, the intake rocker arm assembly 14 may be configured to control the movement of the intake valves in a drive mode. The exhaust rocker arm assembly 16 may be configured to control the movement of the exhaust valves in a drive mode. The engine brake rocker arm assembly 18 may be configured to act on one of the two exhaust valves in an engine brake mode (e.g., at a 4 mm engine brake stroke), as described herein. In certain embodiments, the intake rocker arm assembly 14, the exhaust rocker arm assembly 16, and the engine brake rocker arm assembly 18 may be a mechanical, electrical, hydromechanical, or other suitable valve actuation system.

[0017] With continued reference to Fig. 1A, in certain embodiments, a rocker shaft 22 is received by the valve train carrier 12 and assists in rotating the combined exhaust and engine brake rocker arm assembly 20. As described in more detail herein, the rocker shaft 22 may communicate control fluid (e.g., oil) to the rocker arm assemblies 16, 18 during operation. A camshaft (not shown) may have lift profiles or lobes configured to rotate the rocker arm assemblies 16, 18 to activate the first exhaust valve 26 and the second exhaust valve 28.

[0018] In particular embodiments, the combined rocker arm assembly 20 may generally include a rocker arm body 40, an axle 42, and a roller 44. The rocker arm body 40 may include an exhaust rocker arm portion 46 and an engine brake arm portion 48. The rocker arm body 40 may be rotatably mounted to the rocker arm shaft 22 and have a pair of flanges 50 for receiving the axle 42 such that the roller 44 is disposed on the axle 42 at least partially between the flanges 50. The roller 44 may be configured to engage an exhaust lift lobe or an engine brake lobe of the camshaft. This engagement of the roller 44 causes the combined rocker arm assembly 20 to rotate according to the cam profile of the camshaft, thereby actuating the associated valve(s) as needed. In other embodiments, the combined rocker arm assembly 20 may also include other suitable motion transmitting components, such asa push rod operatively coupled between the rocker arm body 40 and the camshaft for transmitting the valve actuating movement.

[0019] In certain embodiments, the exhaust rocker arm assembly 16 may include an exhaust rocker arm portion 46, which may, for example, define a bore configured to at least partially receive a hydraulic lash adjuster assembly (HLA) or an exhaust capsule (in Fig. 1A not visible) that has an elephant's foot (E-foot) or tappet for contact with the valve bridge. When the roller 44 engages an exhaust lift profile, for example, the exhaust rocker arm portion 46, and hence the exhaust capsule, may be rotated downward, causing downward movement of the valve bridge, which in turn pushes the first exhaust valve 26 and the second exhaust valve 28 associated with a cylinder of an engine (not shown) downward. Although described in this specific manner as an example, this disclosure contemplates rocker arm assemblies with or without an HLA or exhaust capsule. In this regard, for example, in embodiments where the exhaust rocker arm portion is not equipped with a capsule, a valve end or other suitable means of the rocker arm may be used to directly or indirectly act on the valve bridge.

[0020] While certain embodiments of this disclosure may be presented in the context of rocker arms for actuating exhaust valves in an engine braking system, e.g., for use in 1.5- or 2-stroke compression braking, one skilled in the art will nevertheless recognize that the disclosure is not limited to such an application. Various embodiments consistent with this disclosure may be applicable to other types of systems in the valvetrain assembly. For example, embodiments of this disclosure may be used in connection with an intake rocker arm system, an extended valve closing system, an early valve opening system, or other suitable valvetrain systems known to those skilled in the art.

[0021] Fig. 2 shows a perspective view of the exhaust rocker arm assembly 16 and the engine brake rocker arm assembly 18 with a valve bridge 100 and a first exhaust valve 26 and a second exhaust valve 28 installed. As illustrated, the exhaust rocker arm assembly 16 and the engine brake rocker arm assembly 18 may each include a capsule assembly 102. For example, a capsule assembly 102 may be integrated with or coupled to the exhaust rocker arm assembly 16 and the engine brake rocker arm assembly 18 and configured to transmit force or motion to downstream components such as the valve bridge 100. In certain embodiments, each capsule assembly 102 may include a capsule (as shown in FIGS. Fig. 5A and Fig. 6A) that may contact the valve bridge 100. For example, when the exhaust rocker arm assembly 16 and / or the engine brake rocker arm assembly 18 is actuated, the respective capsule may be controlled to expand and press against the valve bridge 100 to move the valve bridge 100. As illustrated, the valve bridge 100 may be disposed between the exhaust rocker arm assembly 16 and the engine brake rocker arm assembly 18, and the first and second exhaust valves 26, 28. In certain embodiments, the valve bridge 100 may be configured to receive the first and second exhaust valves 26, 28. For example, the upper ends 104A, 104B of the first and second exhaust valves 26, 28 may be connected to the valve bridge 100 (e.g., to a bottom of the valve bridge 100).In this way, the actuation force applied to the valve bridge 100 may be transmitted to the first exhaust valve 26 and / or the second exhaust valve 28, causing the first exhaust valve 26 and / or the second exhaust valve 28 to move downward in a vertical direction. By way of example and without limitation, during a first operation (e.g., in exhaust mode), both the first and second exhaust valves 26, 28 may experience the applied force and move downward. By way of further example and without limitation, during a second operation (e.g., in engine braking mode), only the first exhaust valve 26 may experience the applied force and move downward, while the second exhaust valve 28 remains stationary due to the tilting movement of the valve bridge 100.Certain embodiments described herein provide an improved valve bridge 100 capable of exerting a force that causes only the first exhaust valve 26 to move, leaving the second exhaust valve 28 unactuated regardless of the movement of the valve bridge 100. Furthermore, the valve bridge 100 can be configured with a simple structure that facilitates manufacturing while still providing the desired motion transfer.

[0022] The Fig. 3A-3B show perspective views of the valve bridge 100 from above, with parts of the valve bridge 100 in Fig. 3B are cut away for better viewing. In certain embodiments, the valve bridge 100 may be configured to connect the two exhaust valves (such as the first exhaust valve 26 and the second exhaust valve 28 in Fig. 2) spans and rests upon them to transmit power to the exhaust valves. As illustrated, in certain embodiments, a body 300 of the valve bridge 100 may include a first end 302, a second end 306 spaced from the first end 302, and a top surface 308, the top surface 308 connecting the first end 302 and the second end 306. By way of example and without limitation, the first end 302 may be operatively connected to the terminal end of the first exhaust valve 26, and the second end 306 may be generally opposite the first end 302 and operatively connected to the terminal end of the second exhaust valve 28. In certain embodiments, the top surface 308 of the valve bridge 100 may be configured to couple to or engage the exhaust rocker arm assembly 16. For example, an E-foot or a capsule of the capsule assembly 102 (see Fig. 2) the exhaust rocker arm assembly 16 abuts the upper surface 308. In operation, the capsule can be actuated (e.g., based on the exhaust cam profile) to press downward against the upper surface 308 along a center of the valve bridge 100, thereby actuating the valve bridge 100. In this mode, the valve bridge 100 moves downward while maintaining its horizontal orientation to depress the two valves to the same lift. In the illustrated embodiment, the upper surface 308 can generally comprise a flat, horizontal plane. Although the upper surface 308 is described in a particular manner, it is not limited to this configuration. In this regard, the upper surface 308 can have any suitable size and shape to interface with the exhaust rocker arm assembly 16.

[0023] As shown, the body 300 may include a recess 310 that may be disposed on a top surface 316 of the first end 302. In certain embodiments, the recess 310 may be configured to couple to or engage the engine brake rocker arm assembly 18. In certain embodiments, the capsule assembly 102 (see Fig. 2) The engine brake rocker arm assembly 18 may, for example, include an E-butt or tappet shaped like a sphere and configured to be at least partially received by the recess 310. In operation, the E-butt may be actuated (e.g., based on the engine brake cam profile) to press downward against the recess 310, thereby tilting the valve bridge 100. In the illustrated embodiment, the recess 310 may have a shape that is at least partially an ogive. For example, the ogive may be curved to mirror or accommodate the spherical shape of the E-butt. With this structure, contact between the valve bridge 100 and the E-butt may generally occur along a circular contact line 330. This has the advantage of reducing point or edge contact, resulting in lower contact stress and friction, and improving the dynamic behavior of the overall system.Because the recess 310 generally conforms to the contour of the E-foot, the E-foot can be used as a guide to ensure the correct position and movement of the valve bridge 100. For example, when the E-foot presses on the valve bridge 100 via the recess 310 during engine braking, the valve bridge 100 can be actuated to move in all three x, y, and z directions relative to the valves, i.e., displacement in the x and y directions due to a downward component of the E-foot movement tilting the valve bridge 100 (e.g., as shown in FIG. Fig. 6B) and a small displacement in the z-direction due to the angular rotation of the E-foot (e.g., when the E-foot rotates downward, the valve bridge 100 may shift slightly outward away from the axis of rotation). In this case, the recess 310 may comprise two sections, i.e., a lower section (e.g., below the circular contact line 330) formed as an ogive surface for contact with the spherical surface of the E-foot, and an upper section (e.g., above the circular contact line 330) shaped as a truncated cone for guiding the E-foot at least in the x- and y-directions. For example, the configuration of the recess 310 may direct the movement of the valve bridge 100 in all three directions to ensure proper alignment, e.g., B. when the valve bridge 100 rotates downwards and moves back up to its original horizontal position.Although this disclosure describes a valve bridge having a particular first end in a particular manner, this disclosure applies to valve bridges having any suitable first end in any suitable manner. In this regard, in certain embodiments, the first end of the valve bridge may have other suitable structures to kinematically coordinate with the rocker arm. For example, in certain embodiments, the first end may be configured with a convex surface structure to correspond to a concave E-foot, an example of which is described below.

[0024] The Fig. 4A-4B show perspective views of the valve bridge 100 from below, with parts of the valve bridge 100 in Fig. 4B are cut away for clarity of view. In certain embodiments, the body 300 may also include a first valve seat 312 and a second valve seat 314. In particular embodiments, the first valve seat 312 may be disposed on a bottom surface 318 of the first end 302 and positioned generally opposite the recess 310 in the x-direction. The first valve seat 312 may be a channel for receiving the first exhaust valve 26. For example, an upper end 104A (see Fig. 2) of the first exhaust valve 26 seat in the first valve seat 312 and abut a contact surface 320 on the underside of the first valve seat 312. In certain embodiments, the contact surface 320 may be shaped with an S-shaped curvature. By way of example, and not limitation, the contact surface 320 may include a generally flat portion 328 extending between a first curved portion 322 and a second curved portion 324. As illustrated, the first curved portion 322 may point in an opposite direction to the second curved portion 324. For example, the unit normal vector of the first curved portion 322 may point generally upward, while the unit normal vector of the second curved portion 324 may point generally downward.As another example, the curvature of the first curved portion 322 may be the same as or different from the curvature of the second curved portion 324. In this way, the curvature of the contact surface 320 may maintain constant line or surface contact with the associated valve as the valve bridge 100 tilts or translates. In an alternative embodiment, the contact surface 320 may include a first curved surface with a first radius and a second curved surface with a second radius. Additionally, a flat surface may be disposed between the first curved surface and the second curved surface. For example, the center of curvature of the first curved surface may be above the first curved surface, while the center of curvature of the second curved surface may be below the second curved surface.Another example is that the first radius can be identical to or different from the second radius. In certain embodiments, point contact or edge-to-edge contact can be eliminated or at least reduced to improve system kinematics. This also facilitates machining of the valve bridge and provides better structural ergonomics.

[0025] In particular embodiments, the second valve seat 314 may be disposed on a bottom surface 326 of the second end 306 and positioned generally opposite the first valve seat 312 in the y-direction. The second valve seat 314 may be a recess for receiving the second exhaust valve 28. For example, an upper end 104B (see Fig. 2) of the second exhaust valve 28 fit into the second valve seat 314 and abut against a contact surface on the underside of the second valve seat 314. The contact surface may be flat or otherwise curved. As illustrated, the second valve seat 314 may be generally circular in the xy plane. In certain embodiments, the circular shape of the second valve seat 314 may be adapted to accommodate the shape of the upper end 104B of the second exhaust valve 28. As a non-limiting example, the inner diameter of the second valve seat 314 may be slightly larger than the outer diameter of the upper end 104B of the second exhaust valve 28 such that a radial clearance is formed between the second valve seat 314 and the second exhaust valve 28. This configuration may allow movement (e.g.,Tilting of the valve bridge 100 relative to the second exhaust valve 28 while ensuring proper movement and / or force transmission when needed. Although described in this manner, the second valve seat 314 is not limited to this configuration. The second valve seat 314 may have any suitable size and shape known to those skilled in the art for receiving the upper end 104B of the second exhaust valve 28.

[0026] The operation of the valve bridge 100 according to this disclosure will now be described with reference to the Fig. 5A-6B, in which the Fig. 5A-5B show a side view of both the exhaust rocker arm assembly 16 and the engine brake rocker arm assembly 18 in a first position (e.g., in driving mode), and the Fig. 6A-6B show a side view of the exhaust rocker arm assembly 16 and the engine brake rocker arm assembly 18 in a second position (e.g., in engine brake mode).

[0027] With reference to the Fig. 5A-5B, for example, in drive mode, the exhaust rocker arm assembly 16 may oscillate (e.g., in response to a cam main lift profile) and act on the valve bridge 100 by pressing against the top surface 308 of the valve bridge 100 to urge the valve bridge 100 vertically downward. In this case, both the first and second exhaust valves 26 and 28 may be forced open simultaneously. In other words, in drive mode, a horizontal or longitudinal axis of the valve bridge 100 may remain substantially perpendicular to the vertical axes of both the first exhaust valve 26 and the second exhaust valve 28 as the valve bridge 100 is driven downward and the first exhaust valve 26 and the second exhaust valve 28 open to the same valve position.

[0028] Furthermore, the engine brake rocker arm assembly 18 may be on the base circle or deactivated in drive mode. Alternatively or additionally, the first capsule 500 associated with the engine brake rocker arm assembly 18 may be deactivated so as not to transmit any actuating force or movement to the valve bridge 100, even if the engine brake rocker arm assembly 18 rotates such that the valve bridge 100, in particular the recess 310, does not receive any actuating movement from the engine brake rocker arm assembly 18. Although the first capsule 500 is illustrated as sitting in the recess 310 during drive mode, other configurations of the first capsule 500 are also conceivable. For example, the first capsule 500 may be retracted upward (e.g., by controlling a switchable system of the first capsule 500) to avoid contact with the valve bridge 100.

[0029] With reference to the Fig. 6A-6B, for example, in engine braking mode, the exhaust rocker arm assembly 16 may be on the base circle or deactivated. Alternatively or additionally, the second capsule 502 associated with the exhaust rocker arm assembly 16 may be deactivated so as not to transmit any actuating force or movement to the valve bridge 100, even if the exhaust rocker arm assembly 16 rotates such that the valve bridge 100, particularly the upper surface 308, does not receive any actuating movement from the exhaust rocker arm assembly 16. For example, as shown, the second capsule 502 may be spaced from contacting the upper surface 308. Alternatively, the second capsule 502 may be switched to be retractable, e.g., by lost motion mechanisms or other suitable components known to those skilled in the art.

[0030] Furthermore, in engine braking mode, the engine braking rocker arm assembly 18 can rotate according to the lift profile of an engine braking cam. Furthermore, the first capsule 500 is controlled to expand such that the E-foot can press on the first end 302 to impart movement to the first exhaust valve 26 independently of the second exhaust valve 28. That is, the second exhaust valve 28 remains unactuated regardless of the movement of the engine braking rocker arm assembly 18. During engine braking, the valve bridge 100 can be tilted or pivoted by a certain angular degree, with the first end 302 moving downward, e.g., B. generally around the upper end 104B of the second exhaust valve 28. In other words, the first end 302 can move downward and cause the first exhaust valve 26 to open, while the second end 306 generally remains in the same position without actuating the second exhaust valve 28.

[0031] In certain embodiments, a slight drift may occur upon tilting of the valve bridge 100, causing a displacement of the upper end 104A of the first exhaust valve 26 within the first valve seat 312. For example, the upper end 104A may initially be positioned against the flat portion 328 of the first valve seat 312. The drift may displace the upper end 104A so that it moves to the left of the flat portion 328 toward the first curved portion 322. In these embodiments, thanks to the shape of the first valve seat 312, the desired force transmission may be maintained, whereby the force exerted on the first exhaust valve 26 may still be approximately the same force as the force exerted by the first capsule 500, despite the drift in the position of the first exhaust valve 26 relative to the first valve seat 312.

[0032] In certain embodiments, the second valve seat 314 may also be configured to accommodate drift. By way of example and without limitation, the second valve seat 314, as described above, may have an inner diameter that is larger than the outer diameter of the upper end 104B of the second exhaust valve 28, so that the second exhaust valve 28 can translate within the second valve seat 314 (e.g., to the left, as shown). Furthermore, the depth of the second valve seat 314 may be designed deep enough that at least a portion of the upper end 104B of the second exhaust valve 28 is always contained within the second valve seat 314 when the valve bridge 100 is tilted. In this way, the second exhaust valve 28 is prevented from detaching from the valve bridge 100.

[0033] In certain embodiments, the stroke of the engine brake may be approximately 4 mm. When the first capsule 500 is actuated to apply a downward force, the valve bridge 100 may tilt downward and overcome a biasing force of a valve spring (not shown) coupled to the first exhaust valve 26 to lift the first exhaust valve 26 approximately 4 mm from the valve seat (not shown). Meanwhile, by tilting the valve bridge 100, the force transmitted to the second exhaust valve 28 may be minimal, or at least small enough that the second exhaust valve 28 does not shift vertically, compared to the force of the biasing spring. For example, the first exhaust valve 26 may be loaded with 10 kN and the second exhaust valve 28 with 0.5 kN, without limitation.It should be noted that the embodiments presented herein are for illustrative purposes only and are not intended to limit the scope of this disclosure. In certain embodiments, the stroke of the engine brake may be, for example, approximately 2 mm. In other embodiments, the stroke of the engine brake may be less than 4 mm, more than 4 mm, or other suitable values. In further embodiments, the force acting on the first or second exhaust valve may be less than or greater than the values ​​described above.

[0034] The Fig. 7-8 illustrate a second embodiment of a valve bridge according to this disclosure, wherein Fig. 7 shows a perspective view of the valve bridge 700 and Fig. 8 is a side cross-sectional view of the valve bridge 700 during operation. In certain embodiments, the valve bridge 700 may function similarly to the valve bridge 100 in that the valve bridge 700 may be tilted upon actuation by the engine brake rocker arm assembly 18 to force open the first exhaust valve 26 separately from the second exhaust valve 28. Further, the valve bridge 700 may be configured with similar structures to the valve bridge 100, including the body 706 having the first end 708, the second end 710, the top surface 712, the recess 714, the first valve seat 716, and the second valve seat 718. In the embodiment shown, the valve bridge 700 may also include a kinematic cylinder 702 that is rotatably disposed along the Z-direction through a hole 720 at the second end 710.Furthermore, the second valve seat 718 may open into the hole 720 and provide access to the kinematic cylinder 702 inserted through the hole 720. By way of example and without limitation, the kinematic cylinder 702 may be substantially cylindrical in shape and have a flat surface 704 on the underside. The flat surface 704 may be exposed by the second valve seat 718 so that the upper end 104B of the second exhaust valve 28 may pass through the second valve seat 718 and contact the flat surface 704. In certain embodiments, the kinematic cylinder 702 may be used to improve the overall kinematics of the system and increase the contact between the second exhaust valve 28 and the valve bridge 700.For example, when the valve bridge 700 rotates during engine braking mode, the kinematic cylinder 702 can rotate relative to the body 706 so that the flat surface 704 maintains a large contact area with the top end 104B of the second exhaust valve 28 and helps prevent point contact that might otherwise result from tilting of the valve bridge 700. This can be particularly useful in systems with lost-motion components associated with the exhaust rocker arm assembly 16 that may compromise the main exhaust contact area between the second capsule 502 and the top surface 712 of the valve bridge 700, e.g., due to two-stroke engine braking.

[0035] The Fig. 9-10 illustrate a third embodiment of a valve bridge according to this disclosure, wherein Fig. 9 shows a cross-sectional view of the valve bridge 900 used in a rocker arm assembly 902 during engine braking, and Fig. 10 is a perspective, cross-sectional view of valve bridge 900. In certain embodiments, valve bridge 900 may function similarly to valve bridge 700 in that, upon actuation by engine brake rocker arm assembly 904, valve bridge 900 may be tilted to force open first exhaust valve 26 separately from second exhaust valve 28. Further, valve bridge 900 may be configured with similar structures to valve bridge 700, including body 906 having first end 908, second end 910, top surface 912, first valve seat 914, second valve seat 916, and kinematic cylinder 918. In the illustrated embodiment, valve bridge 900 may further include a knob 920 that may be attached to the top of first end 908. As shown, the knob 920 may include a protrusion at the top of the knob 920, which may be spherical, ogive-shaped, or otherwise rounded.For example, the bottom of the knob 920 may be received within a recess 922 on the top side of the first end 908 and extend upward to a certain height above the top side of the first end 908. To engage the knob 920, the capsule assembly 924 of the engine brake rocker arm assembly 904 may be configured with a recess or concave surface 926 shaped to mate with the protrusion on the top end of the knob 920. For further explanation, the configurations of the valve bridge 900 and the engine brake rocker arm assembly 904 are reversed, for example, with respect to the positions of the recess and the corresponding mating structure (e.g., the E-foot or the knob 920), compared to those described above with reference to FIG. Fig. 1-8. In particular embodiments, in addition to the previously mentioned advantage of optimizing system kinematics, the height of the knob 920 can advantageously be adjusted depending on packaging requirements. This can be particularly useful when a different location is needed for the capsule assembly 924. By way of example, and not limitation, the knob 920 can be removably received in the recess 922. Thus, if a different height is needed, the knob 920 can be easily removed and replaced without having to replace the entire valve bridge 900.

[0036] The Fig. 11-12 show a fourth embodiment of a valve bridge according to this disclosure, wherein Fig. 11 shows a cross-sectional view of the valve bridge 1100 used in a rocker arm assembly 1102 during engine braking, and Fig.12 is a perspective view of the valve bridge 1100. In certain embodiments, the valve bridge 1100 may function similarly to the valve bridge 100 in that the valve bridge 1100 may be tilted upon actuation by the engine brake rocker arm assembly 1104 to force open the first exhaust valve 26 separately from the second exhaust valve 28. Further, the valve bridge 1100 may be configured with similar structures to the valve bridge 100, including the body 1106 having a first end 1108, a second end 1110, a top surface 1112, a recess 1114, a first valve seat 1116, and a second valve seat 1118. In the illustrated embodiment, the top surface 1112 may also be provided with surface structures that guide the position or movement of the valve bridge 1100 upon actuation by the exhaust rocker arm assembly 1120.By way of example and without limitation, a guide 1122 may be provided on the top surface 1112, which may be formed as a slot, channel, projection, or other suitable component for engaging the exhaust rocker arm assembly 1120. In the illustrated embodiment, the guide 1122 includes a pair of walls 1124A and 1124B that extend across the entire width of the valve bridge 1100 and define a channel 1126 therebetween for receiving the E-foot 1128 of the exhaust rocker arm assembly 1120. During operation, undesirable drift of the valve bridge may occur, causing the valve bridge to become misaligned with respect to the exhaust rocker arm assembly. In this case, the guide 1122 may prevent the valve bridge 1100 from shifting laterally and maintain the correct alignment and position with respect to the exhaust rocker arm assembly 1120.

[0037] Various embodiments of this disclosure may advantageously provide an optimized solution for the connection between the rocker arms and the valves to enable improved movement and power transmission. By utilizing the novel designs according to this disclosure, the valve bridge may achieve better kinematic behavior with simplified structures and reduced package space. One or more other advantages may be readily apparent to one skilled in the art in light of the figures, descriptions, and claims of this disclosure.

[0038] Herein, "or" is inclusive and not exclusive, unless expressly stated otherwise or the context indicates otherwise. Therefore, "A or B" herein means "A, B, or both" unless expressly stated otherwise or the context indicates otherwise. Also, "and" means both jointly and individually, unless expressly stated otherwise or the context indicates otherwise. Therefore, throughout this text, "A and B" means "A and B jointly or individually" unless expressly stated otherwise or the context indicates otherwise.

[0039] The scope of this disclosure includes all changes, substitutions, variations, modifications, and alterations to the embodiments described or illustrated herein that a person of ordinary skill in the art would understand. The scope of this disclosure is not limited to the example embodiments described or illustrated herein. Moreover, although particular components, elements, parts, functions, operations, or steps are described and illustrated in this disclosure, each of these embodiments may include any combination or permutation of the components, elements, parts, functions, operations, or steps described or illustrated herein that a person of ordinary skill in the art would understand.Furthermore, reference in the appended claims to a device or system, or a component of a device or system, that is adapted, arranged, capable, configured, enabled, operable, or ready to perform a particular function of that device, system, or component, regardless of whether it or the function in question is activated, switched on, or enabled, as long as the device, system, or component is so adapted, arranged, capable, configured, enabled, operable, or ready to function. Although certain embodiments are described or illustrated in this disclosure as being particularly advantageous, certain embodiments may provide none, some, or all of these advantages. QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited patent literature

[0000] US 63 / 382,470

[0001]

Claims

[1] Valve bridge for a rocker arm assembly, the valve bridge comprising: a first end, a second end opposite the first end, and an upper surface of a bridge body portion connecting the first and second ends, the upper surface of the bridge body portion being configured to engage a first rocker arm; a first recess disposed at a top of the first end, the first recess having a shape that is at least partially an ogive and configured to engage a second rocker arm; a first valve seat disposed on a bottom surface of the first end and having a curved bottom surface for engaging a first valve; and a second valve seat disposed on a bottom surface of the second end for engaging a second valve; wherein the valve bridge is configured to moves vertically when actuated by the first rocker arm to actuate both the first and second valves, or when actuated by the second rocker arm, tilts at an angle to actuate the first valve without actuating the second valve. [2] The valve bridge of claim 1, wherein the engagement between the first recess and the second rocker arm forms a circular line of contact. [3] Valve bridge according to claim 1, wherein the first valve seat is a channel. [4] The valve bridge according to claim 1, wherein the curved bottom surface of the first valve seat is S-shaped. [5] Valve bridge according to claim 1, wherein the curved bottom surface of the first valve seat allows lateral displacement of the first valve relative to the valve bridge. [6] Valve bridge according to claim 1, wherein the second valve seat has a second recess. [7] The valve bridge according to claim 1, wherein an inner diameter of the second valve seat is larger than an outer diameter of a port of the second valve. [8] The valve bridge according to claim 1, wherein the second end has a horizontal through-hole and a kinematic cylinder rotatably inserted into the horizontal through-hole. [9] The valve bridge of claim 8, wherein the kinematic cylinder engages the second valve and maintains surface contact with the second valve when the valve bridge tilts. [10] The valve bridge of claim 1, wherein the upper surface includes a guide for guiding movement of the valve bridge relative to the first rocker arm. [11] Valve bridge for a rocker arm assembly, the valve bridge comprising: a first end, a second end opposite the first end, and an upper surface of a bridge body portion connecting the first and second ends, the upper surface of the bridge body portion being configured to engage a first rocker arm; a projection disposed on a top surface of the first end and having an ogive shape at an upper end of the projection for engaging with a second rocker arm; a first valve seat disposed on a bottom surface of the first end and having a curved bottom surface for engaging a first valve; and a second valve seat disposed on a bottom surface of the second end for engaging a second valve; wherein the valve bridge is configured to moves vertically when actuated by the first rocker arm to actuate both the first and second valves, or when actuated by the second rocker arm, tilts at an angle to actuate the first valve without actuating the second valve. [12] A valve bridge according to claim 11, wherein the engagement between the projection and the second rocker arm forms a circular line of contact. [13] A valve bridge according to claim 11, wherein the projection is removably received in a recess arranged on the top side of the first end. [14] A valve bridge according to claim 11, wherein the curved bottom surface of the first valve seat is S-shaped. [15] Valve bridge according to claim 11, wherein the curved bottom surface of the first valve seat allows lateral displacement of the first valve relative to the valve bridge. [16] Rocker arm assembly, which includes: a first rocker arm and a second rocker arm; a first valve and a second valve; and a valve bridge configured to be selectively actuated by the first rocker arm or the second rocker arm, the valve bridge comprising a first end, a second end opposite the first end, and an upper surface of a bridge body portion connecting the first end and the second end, the upper surface of the bridge body portion being configured to engage the first rocker arm, a recess disposed on a top side of the first end, the recess having a shape that is at least partially an ogive and configured to engage a spherical end of the second rocker arm, a first valve seat disposed on a bottom surface of the first end and having a curved bottom surface for engaging the first valve, and a second valve seat disposed on a bottom surface of the second end for engaging the second valve; wherein the valve bridge is configured to moves vertically when actuated by the first rocker arm to actuate both the first and second valves, or when actuated by the second rocker arm, tilts at an angle to actuate the first valve without actuating the second valve. [17] The rocker arm assembly of claim 16, wherein the first rocker arm is an exhaust rocker arm and the second rocker arm is an engine brake rocker arm. [18] Rocker arm assembly according to claim 16, wherein the engagement between the recess and the spherical end of the second rocker arm forms a circular line of contact. [19] The rocker arm assembly of claim 16, wherein the second end includes a horizontal through-hole and a kinematic cylinder rotatably inserted into the horizontal through-hole. [20] The rocker arm assembly of claim 16, wherein the upper surface includes a guide for guiding movement of the valve bridge relative to the first rocker arm.

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