Valve bridge restraint and guide and related methods

Abstract

Valve bridge systems include restraints and guides for managing bridge jump and other uncontrolled valve bridge motion during engine operation. The restraints can include a dog collar, an extension on the bridge, and a bridge stop pin. The guides can include a valve stem tip introduction ramp around a valve bridge valve pocket, and a deflection surface on the bridge extension. Methods of constructing a valve bridge can include constructing a valve stem tip introduction ramp based on a worst case position of the valve bridge defined by one or more of the restraints provided by the dog collar, the extension, and the stop pin, or combinations thereof.

Description

Technical Field

[0001] This disclosure generally relates to valve actuation systems in internal combustion engines, and more particularly to valve bridge systems including restraints and guides for managing bridge scrambling and other uncontrolled valve bridge movements during engine operation. The restraints may include an e-foot collar, an extension on the bridge having a lower guide surface, and a bridge brake pin. The guides may include a valve stem head guide ramp surrounding the valve recess on the valve bridge, and a deflection surface on the bridge extension. This disclosure also generally relates to a method of constructing a valve bridge having restraints and guides. Background Technology

[0002] Valve actuation systems for internal combustion engines are known in the art. Such valve actuation systems typically include a valve mechanism, which in turn includes one or more components that transmit valve actuation motion from a valve actuation motion source (e.g., one or more cams) to the engine valves. Figure 1 A typical exhaust valve actuation subsystem in a prior art valve actuation system with an idler valve bridge 600 / 700 is shown. It should be understood that similar components can be used to actuate the intake valve. The main exhaust rocker arm 100 / 400 can be pivotally mounted and adapted to rotate about a rocker arm shaft 110. A follower 120 can be disposed at one end of the main exhaust rocker arm 100 / 400 and can contact and follow a motion source (i.e., a rotating cam 260) to transmit motion to the rocker arm. The cam 260 can be controlled by a controller 265 and can include a single main exhaust cam 262 (or, in the case of an intake valve actuation system, a main intake cam). As is known in the art, hydraulic fluid can be supplied from a hydraulic fluid source (not shown) to the rocker arm 100 / 400 under the control of a solenoid hydraulically controlled valve (not shown). The hydraulic fluid can flow through a passage 510 formed in the rocker arm shaft 110 to a hydraulic passage 215 formed within the rocker arm 100 / 400. The return or auxiliary path 520 can also be formed in the rocker arm shaft.

[0003] Still refer to Figure 1The rotating foot, often referred to as the elephant foot or e-foot 240, can be part of a screw assembly 230 located at one end of the rocker arm 100 / 400 to transmit motion from the rocker arm 100 / 400 to the valve bridge 710, which spans two or more engine valves 810 / 890 and 820 / 920 associated with a given cylinder. In many cases, such a valve bridge allows another component of the valve mechanism (e.g., the rocker arm) to simultaneously actuate these engine valves engaged with the valve bridge via a brake pin 650 / 700 located in a bore 714. The position of the rotating foot 240 relative to the rocker arm 100 / 400 can be adjusted using an adjusting screw 232 secured by a threaded fastener 234, thereby providing adjustment of the clearance (i.e., the gap between the rotating foot 240 and the valve bridge 710). A hydraulic passage 235 communicating with the rocker arm passage 215 can be formed in the screw 232 to deliver fluid from the rocker arm passage 215 to the valve bridge. The swivel foot 240 can contact the idle valve bridge 600 / 700. The exhaust valve bridge 600 / 700 may include a valve bridge body 710 having a central opening 712 extending through the valve bridge and a side opening 714 extending through a first end of the valve bridge. The side opening 714 may receive a sliding pin 650 that contacts the valve stem of the first exhaust valve 810. The valve stem of the second exhaust valve 820 may contact the other end of the exhaust valve bridge.

[0004] Ideally, during operation, the opposing forces exerted by the motion transmission components (e.g., rocker arms) and the engine valve springs ensure that the valve bridge remains in contact with both the motion transmission components and the engine valves simultaneously (allowing for normal clearance setting). In this way, the valve bridge always remains aligned with and positioned to transmit valve actuation motion to the engine valves. As used herein, this state of the valve bridge is referred to as the "controlled state" of the valve bridge relative to the engine valves.

[0005] Some valve actuation systems are configured to provide so-called auxiliary valve actuation motion, i.e., valve actuation motion other than that used to operate the engine in a positive power generation mode through fuel combustion. In such valve actuation systems, valve mechanism components (e.g., tappets, pushrods, rocker arms, valve bridges, etc.) may be configured to include devices or idling assemblies that allow valve actuation motion to be transmitted to the engine valves via the valve mechanism components, or selectively "idle," in which case such motion is not transmitted to the engine valves via the valve mechanism components. A signal for activating or deactivating the idling assembly and thereby causing the idling assembly to absorb or transmit motion can be provided by hydraulic (oil) pressure controlled by the upstream solenoid valve. Figure 1An example of such a system is shown in U.S. Patent Application Publication No. 2012 / 0024260, the teachings of which are incorporated herein by reference. In this case, the valve bridge assembly 600 / 700 is provided with a idling assembly in the form of a locking mechanism. The central opening 712 of the exhaust valve bridge 600 can receive an idling or locking assembly comprising an outer plunger 720 disposed in an outer plunger bore 722, a cap 730 disposed in the outer plunger 720, an inner plunger 760, an inner plunger spring 744, an outer plunger spring 746, and one or more wedge rollers or balls 740. A rotating foot 240 engages with the cap 730 and thus transmits motion to the outer plunger 720, and ultimately to the bridge 600 and valves if the outer plunger 720 is locked relative to the bridge 600. In the illustrated embodiment, the locking mechanism ball 740 may be located in the inner plunger recess 762 and, when the inner plunger 760 moves upward, is forced through the opening in the outer plunger 720 and engages with the recess 770 formed in the body of the valve bridge. In this state, due to the outer diameter of the inner plunger 760, the ball 740 is prevented from disengaging from the recess 770, thereby locking the outer plunger 720 in a fixed relationship relative to the valve bridge 710. Therefore, any valve actuation motion applied to the outer plunger 720 by the rocker arms 100 / 400 is transmitted to the valve bridge 710 and the engine valves 810 / 910, 820 / 920. However, when the recess formed in the inner plunger 760 aligns with the ball 740, the ball can freely disengage from the recess 770 in the valve bridge 710, thereby unlocking the outer plunger 720 and allowing it to reciprocate relative to the valve bridge 710. In this state, any valve actuation motion applied to the outer plunger 720 causes the outer plunger to move within the valve bridge 710 and is not transmitted to the engine valves. Another valve bridge-based locking / unlocking system is disclosed in U.S. Patent Application Publication No. 2014 / 0326212, the teachings of which are incorporated herein by reference.

[0006] However, in Figure 1In systems of the type described, there is a possibility of partial engagement of the locking mechanism, particularly in operating environments where the valve bridge reciprocates rapidly and is under high load. For example, partial engagement may occur in existing systems (such as those described above) where the inner plunger or latch piston moves and disengages from full engagement with the ball or wedge element. In this case, slippage of the locking mechanism is possible during engine operation, during rapid load changes, and during high-speed vibrations of the bridge and other valve mechanism components. Partial engagement and slippage of the locking mechanism may occur after the normal valve actuation movement (i.e., the valve opening movement) is initially applied to the engine valve by the bridge. This slippage following the initial movement can cause a rapid release of valve spring energy when one or both engine valves violently strike their respective valve seats to close. When this occurs, the force provided by the valve actuation components for opening the engine valve is abruptly eliminated, allowing the engine valve to accelerate rapidly to the closed position without restriction under considerable force from the valve spring. When the engine valve reaches its fully closed position (i.e., resting on the valve seat formed in the cylinder head), the momentum of the valve bridge can cause it to "jump" from the valve stem head. That is, the valve bridge will continue to move in an uncontrolled manner, typically away from and / or out of alignment with one or both of the engine valve stems. This movement can create the possibility of the valve bridge colliding with the valve mechanism or rocker arms or other components in the engine cylinder head environment. In extreme cases, the valve bridge may completely jump out of one or both valve stem heads and remain detached from the engine valve, leading to engine failure and / or damage. Uncontrolled states of the valve bridge are also known to occur due to overspeeding of the internal combustion engine. This type of movement of the valve bridge (moving to a position where system stability or operation is compromised) will be referred to herein as "uncontrolled movement," and as used herein, this state in which the valve bridge is in a position where system stability or operation is compromised is referred to as an "uncontrolled state" of the valve bridge relative to the engine valve.

[0007] Given the potential for valve bridge scrambling, misalignment, and associated harmful effects on engine and valve actuation system operation and wear in existing systems, solutions to prevent, minimize, adapt to, or guide uncontrolled valve bridge states or positions (regardless of cause) would represent a welcome addition to the field. Summary of the Invention

[0008] According to one aspect of this disclosure, the valve bridge may include constraint and guide elements for controlling and managing changes in valve bridge movement during engine operation. The constraint elements contemplated in this disclosure include an elephant foot collar adapted to surround the elephant foot and an extension on the valve bridge adapted to be fitted between valve springs. The guide elements contemplated in this disclosure include: an introduction ramp surrounding a valve recess on the valve bridge for guiding the valve stem head into the valve recess when the valve bridge is misaligned; and a deflection surface on the extension for preventing the extension from getting stuck on sharp corners or other features in the valve bridge environment. The disclosed constraint and guide features prevent uncontrolled bridge jumps or other bridge movements that would otherwise be uncontrollable, and thus keep the valve bridge in a controlled state throughout engine operation.

[0009] According to one aspect, this disclosure provides a valve bridge for use with an engine valve assembly of an internal combustion engine, the engine valve assembly including a plurality of engine valves, the internal combustion engine having a valve mechanism for transmitting motion from a motion source to the valve bridge, the valve mechanism including an elephant foot adapted to engage with the valve bridge, the valve bridge including: a central bridge housing; a locking assembly disposed in the central bridge housing and having an elephant foot engagement surface, the locking assembly being adapted to selectively lock or allow movement of the elephant foot engagement surface relative to the central bridge housing, thereby transmitting or absorbing motion; and a bridge, the bridge further including a control surface arranged to contact the elephant foot when the bridge is about to move into an uncontrolled state, the control surface thereby holding the bridge in a controlled state throughout engine operation. According to another aspect, the control surface may be defined by a collar, the collar being circular and may completely or partially surround the elephant foot engagement surface on the bridge. According to another aspect, the elephant foot engagement surface may be located on a plunger or piston assembly disposed in the central bridge housing. According to another aspect, the control surface may extend from the central bridge housing a sufficient distance to constrain movement of the valve bridge relative to the elephant foot, thereby holding the bridge in a controlled state. According to another aspect, the control surface may extend sufficiently from the central axle housing to limit the movement of the valve bridge by a maximum controlled displacement. According to another aspect, the valve bridge may include: a valve recess defining a valve stem seat for receiving a valve stem head; and an introduction surface adapted to guide the valve stem seat to align with the valve stem head when the bridge moves to an uncontrolled position. According to another aspect, the introduction surface may be a ramp. According to another aspect, the introduction surface may extend sufficiently from the valve seat to guide the valve stem seat alignment when a maximum bridge jump displacement will occur. According to another aspect, an extension having at least one lower guide surface may be disposed near the central axle housing and may have at least one lower guide control surface configured to limit bridge movement by engaging with a valve spring assembly to hold the bridge in a controlled state, the valve spring assembly including a valve spring and a valve spring retainer, the valve spring retainer being oversized. According to another aspect, the valve bridge may include a brake pin disposed in a brake pin hole to further constrain the movement of the valve bridge. Furthermore, according to one aspect, the disclosed constraint elephant foot collar and extension provide constraints on the worst-case deviation of the valve bridge position, and thus limit the worst-case deviation of the valve bridge position. This worst-case position can be used to construct guiding surfaces, such as introduced ramps, to ensure that for all possible erroneous movements that may occur, the introduced ramps capture and guide the valve bridge back to an aligned and controlled position. Therefore, the valve bridge remains in a controlled position, and valve bridge jumps and erroneous uncontrolled movements are prevented.

[0010] According to one aspect, a valve bridge may include an elephant foot collar having a control surface surrounding the elephant foot, thereby constraining the movement (translation, pitch, roll, or yaw) of the valve bridge relative to the elephant foot. According to another aspect, a valve bridge for use with an engine valve assembly of an internal combustion engine, the engine valve assembly including a plurality of engine valves, the internal combustion engine having a valve mechanism for transmitting motion from a motion source to the valve bridge, the valve mechanism including an elephant foot adapted to engage with the valve bridge, the valve bridge including: a central bridge housing; a locking assembly disposed in the central bridge housing and having an elephant foot engagement surface, the locking assembly being adapted to selectively lock or allow movement of the elephant foot engagement surface relative to the central bridge housing, thereby transmitting or absorbing motion; and a bridge, the bridge further including a control surface arranged to contact the elephant foot when the bridge is about to move into an uncontrolled state, the control surface thereby holding the bridge in a controlled state throughout engine operation.

[0011] According to another aspect, a valve bridge may include an extension on the bridge defining one or more control surfaces arranged and adapted to engage with a valve spring and / or a valve spring retainer when the valve bridge position deviates from a controlled state, thereby restraining the movement of the valve bridge.

[0012] According to another aspect, the valve bridge may include a valve stem head introduction ramp surrounding the valve recess. The introduction ramp is configured to capture the valve stem head at all possible locations of the valve bridge relative to the valve stem head, such as those defined by constraints such as an elephant foot collar control surface and / or an extension control surface.

[0013] According to another aspect, the axle brake pin can be combined with an elephant foot collar restraint to provide further restraint on axle movement. This configuration can be further combined with extension restraints, valve inlet surfaces surrounding the valve recesses of the valve bridge, and / or deflection surfaces on the axle extensions, each feature used alone or in combination with one or more other features.

[0014] According to another aspect, the bridge extension may be provided with deflection features to prevent the bridge extension from getting stuck on sharp corners or surfaces in the overhead engine environment during engine operation.

[0015] According to another aspect, a method for constructing a valve bridge control surface includes: evaluating the extreme positions of the valve bridge in both a locked and unlocked state; constructing an elephant foot collar to constrain bridge movement; optionally constructing an extension control surface to constrain bridge movement; and optionally constructing a valve stem head introduction ramp based on the constraint defined by the elephant foot collar and / or the extension. Attached Figure Description

[0016] The foregoing and other features and advantages will be discussed in detail in the following non-limiting description of a particular embodiment, in conjunction with the accompanying drawings, wherein:

[0017] Figure 1 It is a cross-sectional view of a valve actuation system including a valve bridge with a locking mechanism according to the prior art;

[0018] Figure 2 This is a diagram of the lower front perspective view of the valve bridge according to this disclosure;

[0019] Figure 3 This is a diagram of the upper front perspective view of the valve bridge according to the present disclosure;

[0020] Figure 4 yes Figure 2 and Figure 3 Bottom view of the valve bridge;

[0021] Figure 5 This is a cross-sectional view of the valve bridge (along...) Figure 3 Section line 5-5 in the figure shows the valve bridge in a partially skipped state;

[0022] Figure 6 yes Figures 2 to 5 A perspective view of the valve bridges deployed in an internal combustion engine and in a controlled state;

[0023] Figure 7 yes Figures 2 to 6 An illustration of a perspective view of a valve bridge deployed in an internal combustion engine in an uncontrolled state, in which the valve bridge is separated from the valve stem head;

[0024] Figures 8A to 8C yes Figures 2 to 7 A cross-sectional view of the valve bridge, showing the sequence of valve bridge skipping conditions or events;

[0025] Figure 9 This is a partial sectional view of the valve bridge (along...) Figure 3 Line 9-9 in the middle, where the valve bridge is at the peak jump height;

[0026] Figures 10A to 10D A partial cross-section shows the sequence by which the valve stem head introduction ramp, according to this disclosure, holds the valve bridge in a controlled state;

[0027] Figure 11 This is a schematic diagram of the introduced inclined plane construction and exemplary bridge constraint geometry according to this disclosure;

[0028] Figure 12 A cross-sectional view is shown of a brake pin and elephant foot collar constraint construction according to one aspect of the present disclosure;

[0029] Figure 13 An exemplary method or process for constructing a valve bridge control surface according to this disclosure is shown. Detailed Implementation

[0030] Reference Figures 2 to 6 According to this disclosure, the valve bridge 200 includes a guide feature in the form of a collar or a vertically extending wall 202, which is adapted to engage the valve bridge 200 and control the movement of the valve bridge relative to the rocker arm. See details... Figure 6 The rocker arm 206's elephant foot (also called the rotating foot) 204 is adapted to engage with the valve bridge 200 when the valve bridge 200 is deployed into the engine environment (i.e., installed). A collar 202 can extend upward from a body portion 220, which may have a central bridge housing to accommodate components of the bridge locking or collapse mechanism 250. The collar 202 may define a control surface 203 internally therein for restraining movement of the valve bridge 200 relative to the elephant foot 204, thereby preventing uncontrolled movement of the valve bridge relative to the elephant foot. The collar 202 may include one or more flat areas on its outer surface. Figure 6 This provides clearance and / or constraint for the movement of the valve bridge relative to other engine components in the overhead environment. The collar 202 and control surface 203 may completely surround the elephant foot engagement surface 252, which may be positioned similarly to... Figure 1 The cover 730 described in the context is disposed on the cover 254 of the locking assembly or mechanism 250. As will be appreciated, this disclosure contemplates variations of the continuous surface shown in this example, such as discontinuous or discontinuous surfaces extending upward and surrounding the elephant foot engagement surface. For example, the collar need not be a complete, continuous circular feature. Discontinuous walls may be present, with grooves or spaces between the discontinuous walls, thereby forming multiple control surfaces surrounding the elephant foot. The dimensions of these grooves or spaces may be set such that the elephant foot is prevented from passing laterally through the grooves or spaces.

[0031] Figure 3 An isometric top front view of an exemplary bridge 200 is shown. Figure 3Also shown is a three-dimensional reference space defined by three axes and useful for understanding bridge motion in the context of this disclosure: a longitudinal axis 10 extending through the locking mechanism (center of the central bridge housing) and the valve stem recess; a transverse axis 20 extending perpendicular to the longitudinal axis 10 and through the locking mechanism; and a vertical axis 30 extending perpendicular to the longitudinal axis 10 and the transverse axis 20. This reference space provides a frame of reference for describing the various bridge motions that the constraint features of this disclosure can limit or accommodate. As will be understood from this disclosure, the corresponding tendency of bridge jump and bridge to move toward an uncontrolled state can involve one or more of the following: translation, rotation, pitch, roll, or yaw relative to one or more of these three axes. For example, bridge jump can involve upward translation of the valve bridge 200 along the vertical axis, pitch of the valve bridge 200 relative to the longitudinal axis (i.e., pitch causing one valve stem recess to rise above another valve stem recess), and roll about the longitudinal axis (i.e., roll causing the valve bridge to rotate about the longitudinal axis). According to this disclosure, the movement of the valve bridge can be constrained to prevent or accommodate any one or a combination of these movements, such that the valve bridge is kept in a controlled state (or in other words, to prevent the valve bridge from moving into a state that would be uncontrolled).

[0032] like Figure 6 As shown, the vertical range or height of the collar 202 can be configured such that, as... Figure 6 During controlled operation of the valve bridge 200 shown, when the locking mechanism is locked in place and at its maximum height or travel relative to the valve bridge body 220, the bottom surface elephant foot 204 is positioned above the end edge 209 of the control surface 203. This configuration, for example, facilitates easy installation and removal of the bridge 200. Furthermore, the vertical range or height of the collar 202 allows the elephant foot 204 to translate into the space defined by the collar 202 and the control surface 203 during the collapsed or unlocked state of the locking assembly or mechanism 250 included in the valve bridge 200. The dimensions of the control surface 203 are also configured (i.e., having a sufficiently large diameter) not to engage with the elephant foot during normal controlled movement of the valve bridge 200. However, the dimensions of the control surface 203 are also configured (i.e., having a sufficiently small diameter) to provide engagement between the control surface 203 and the elephant foot 204 when the valve bridge moves relative to the elephant foot toward an uncontrolled position. That is, during the movement of the valve bridge relative to the valve stem toward an uncontrolled state or position (such as horizontal or vertical translation, pitch, roll, or yaw), the collar 202 can surround the valve stem 204 and operate to contact the valve stem (regardless of the collapsed / uncollapsed or locked / unlocked state of the collapse mechanism), thereby limiting any translational or other movement of the valve bridge 200 and holding the valve bridge 200 in a controlled state. This is in Figure 7As shown, the movement of the valve bridge toward an uncontrolled position or state has disengaged the valve bridge from, for example, the engine valve stem 602. However, as Figure 6 and Figure 7 As shown in both, the collar 202 is configured to have sufficient vertical range to contact the valve foot 204 when the valve bridge moves relative to the valve foot into an uncontrolled state or position, thereby reducing any tilting or misalignment of the valve bridge.

[0033] According to other aspects of this disclosure, such as Figure 6 and Figure 7 As shown, the valve bridge 200 may include an extension 208. Figure 2 An additional guide feature in the form of an extension having a control surface 283 and configured to extend between (but immediately adjacent to) the engine valve spring 302 and / or the engine valve spring retainer 304. Examples of various embodiments of such an extension are described in U.S. Patents 10,883,392, 11,053,819, and 11,319,842, the disclosures and subject matter of which are incorporated herein by reference in their entirety. As described in these documents, the extension 208 is configured to remain non-contacting with the valve spring 302 and / or retainer 304 during controlled operation of the valve bridge 200, but is configured to contact the valve spring 302 and / or retainer 304 when the valve bridge moves toward an uncontrolled position, thereby limiting tilting / rotation or other undesired movement of the valve bridge 200 toward an uncontrolled state. The extension 208 may have a tapered and / or conical deflection surface 281 at its end. Figure 2 and Figure 3 When bridge 200 experiences a jump or movement toward an uncontrolled position, this feature prevents bridge extension 208 from getting stuck on corners or other sharp features in an overhead environment (i.e., near the space between valve springs where extension 208 is normally located). Deflection surface 281 thus prevents bridge 200 from becoming uncontrolled and guides bridge 200 back to a controlled position in the event of a deviation from a controlled state or position.

[0034] Figures 8A to 8C The sequence of valve bridge jumps in a valve bridge with the described guide features is shown. Figure 8A In this configuration, the bridge 200 is in a controlled position relative to the valve stem heads 602, wherein each valve stem head 602 is aligned with and seated within a valve stem head recess 212. Here, the bridge locking mechanism is locked in the extended position relative to the bridge 200. Figure 8BThe diagram illustrates the beginning of a valve bridge jump, where the valve bridge 200 has displaced from the valve stem head 602. This can occur when slippage exists in the locking mechanism due to partial engagement of the locking element. Therefore, and due to the valve spring force, the valve stem head 602 can suddenly snap upwards when the valves close violently by striking their respective valve seats. This action ejects the valve bridge upwards and displaces it from the valve stem head. Figure 8C The full range of possible bridge jumps is shown, with the upper limit reached when the locking mechanism collapses to its internal boundary within the central housing of the valve bridge. Figure 9 This is another cross-sectional view showing the position of the elephant's foot inside the loop at the peak jump height.

[0035] As will be understood, although the bridge jump shown is a purely upward translation and involves valve stem head recesses 212 being equidistant from their corresponding valve stem heads 602, it should be understood according to this disclosure that the constraint and guiding features described herein can mitigate or accommodate (guide counteract) other undesirable bridge movements, such as pitch of the valve bridge 200 relative to its longitudinal axis, in which case one valve stem head recess 212 will be further away from its corresponding valve stem head 602 than the other valve stem head 212. The collar 202 and control surface 203 will thus limit the pitch of the valve bridge relative to its longitudinal axis, as the control surface 203 will collide with the elephant's foot before the bridge pitches to an uncontrolled position. The collar 202 and control surface 203 are also configured to prevent roll of the valve bridge 200 relative to its longitudinal axis. As will be appreciated, such movement can also be considered as pitch of the valve bridge 200 relative to its lateral axis.

[0036] According to various aspects of this disclosure, the valve bridge may also be provided with guide features that accommodate movement toward an uncontrolled state or position (relative to the valve stem head) and guide the valve bridge back to a controlled state or position (relative to the valve stem head). See again Figures 2 to 9 and Figures 10A to 10D The valve bridge 200 may include control surfaces in the form of guide ramps 210, which substantially surround the valve stem head recess 212. Each guide ramp 210 is configured and adapted to receive a corresponding engine valve stem 602 and guide the valve stem 602 back into the valve recess when the valve bridge is misaligned or moves toward an uncontrolled position relative to one or both of the valve stems 602. Figures 10A to 10DThe sequence of the skipped valve bridge 200 being guided back to a controlled state is shown in cross-section. The lead-in ramp 210 at each valve stem head recess 212 is large enough to mate with the outer diameter of the valve stem head 602 when the valve bridge 200 moves to a worst-case deviation from the controlled position (i.e., one or more of translation, pitch, roll, and yaw, or a combination thereof). The lead-in ramp 210 is configured to guide the valve bridge 200 back to one or both valve stem heads after a bridge skip, misalignment, or other event in which the valve bridge would tend to move toward an uncontrolled position. From Figure 10A Initially, as the valve stem head recess 212 disengages from the valve stem head 602, the valve bridge 200 is moving towards an uncontrolled state. Furthermore, as... Figure 10A As shown, due to bridge translation or yaw (about the vertical axis), valve stem head recess 212 may also misalign with valve stem head 602. As will be appreciated, valve bridge 200 may also experience roll or pitch. According to various aspects of this disclosure, also as Figure 10A As shown, by contacting the elephant foot 204 via the collar 202, the bridge 200 is constrained to prevent excessive translation (i.e., along the lateral and longitudinal axes) and excessive roll (around the longitudinal axis), thereby limiting erroneous uncontrolled movement of the valve bridge 200. This constraint, in turn, limits misalignment of the valve stem head recess 212 relative to the valve stem head 602. Figure 10B In this configuration, the valve bridge 200 can be moved to a position where it contacts the valve stem head 602 (where, for example, rotation of the rocker arm 206 and / or the stroke or locking of the locking mechanism forces the valve bridge 200 toward the engine valve). In this example, a ramp 210 is introduced to contact the outer edge of the valve stem head 602. Figure 10C and Figure 10D As shown, the inclined construction of the introduced ramp 210, combined with the continuous contact between the outer diameter of the valve stem head 602, causes the valve bridge 200 to rotate / translate or otherwise return to the position where the valve stem head recess 212 is aligned with the valve stem head 602.

[0037] Figure 11This is a geometric representation of a bottom view of an exemplary introduction ramp 210 configuration superimposed on a representation of the outer circumference 620 of the valve spring, and a schematic cross-section of an exemplary valve bridge extension 208 having a control surface 283. According to various aspects of this disclosure, the dimensions of the valve bridge introduction ramp (such as the diameter of the introduction ramp edge circle 211) can be configured to accommodate a defined maximum movement of the valve bridge relative to the valve stem head. According to various aspects of this disclosure, this defined maximum movement can be defined by constraints provided by control surfaces 203 on the collar 202 and / or control surfaces on the extension 208. In this example, when the valve spring retainer is made to have an outer circumference larger than the outer circumference of the spring, the engagement point of the extension 208 with the outer circumference of the valve spring 620, or in an alternative constraint configuration with the valve spring retainer (…),… Figure 6 The maximum yaw of extension 208 (around the vertical axis extending into the page) is determined by the engagement point of 304 in the valve bridge. The extent of the introduction ramp 210 (in this case, the diameter) can be selected to accommodate this maximum movement and may also include tolerances for additional clearance 213. Thus, according to various aspects of this disclosure, the maximum (worst-case) movement of valve bridge 200 relative to valve stem head 602 (translation, pitch, roll, and yaw relative to the longitudinal, lateral, and vertical axes) can be defined based on the aforementioned constraints (i.e., the collar control surface and the extension control surface). The introduction ramp can then be configured to accommodate the determined maximum movement, with some variation tolerances. In other words, the introduction ramp is configured to be large enough to capture and guide the valve stem head at all possible positions of the bridge relative to the valve stem head, as defined by the constraint features on the valve bridge (i.e., the extension control surface 283 and / or the collar control surface 203). In this way, the valve bridge can be readily configured to prevent bridge jump and uncontrolled operation.

[0038] Although Figures 2 to 6 The embodiment of valve bridge 200 shown and described herein illustrates a combination of collar 202, extension 208, and inlet ramp 210; however, it should be understood that not all three of these features need to be included in all embodiments of the valve bridge according to this disclosure. That is, instead of combining all three of these features, collar 202 may be implemented as a single feature or in combination with extension 208 or inlet ramp 210. Furthermore, although these three features have been shown in the context of valve bridges including collapse mechanisms, it should be noted that this is not necessary. That is, it should be understood that these features (again, individually, jointly, or in combination thereof) can also be used in valve bridges that do not include collapse mechanisms.

[0039] Figure 12Another constraint configuration according to various aspects of this disclosure is shown. In this example, the axle brake pin 280 may be used in conjunction with the collar 203 to provide additional constraint on axle movement. The axle brake pin 280 may have a first diameter portion 282 extending through the bore 270 and arranged to engage with the brake piston assembly 400. The brake pin base 284 may have a larger diameter than the first diameter portion 282 and may be disposed within a countersunk hole 290 in the axle. The dimensions of the brake pin base 284 and the first diameter portion 282, as well as the dimensions of the bore 270 and the countersunk hole 290, may be configured to provide defined constraints on the movement of the valve bridge 200 during braking operation or other events. As will be appreciated, the brake pin features can provide constraints on translation and yaw (about the vertical axis), which enhances the constraint on the movement provided by the collar 203, thereby providing improved control over valve bridge movement and preventing axle scrambling and uncontrolled movement during engine operation.

[0040] Figure 13 The process 1300 for constructing the bridge constraint and guide according to this disclosure is shown. At 1302, the locked bridge position (relative to the valve stem head) at the cam base circle is evaluated. At 1304, the locked bridge position at peak cam lift is evaluated. At 1306, the position of the fully collapsed bridge is evaluated. At 1308, the elephant foot collar control surface is configured to constrain the bridge movement to a controlled state. At 1310, the extension control surface is constructed. At 1312, the valve stem head introduction control surface (guide) is constructed based on the worst-case bridge movement determined based on the evaluations at steps 1302 to 1310. At 1314, it can be verified that the bridge control surface does not interfere with other components in the overhead environment during normal engine operation.

[0041] Although specific embodiments of the invention have been described with reference to particular exemplary embodiments, it will be apparent that various modifications and changes can be made to these embodiments without departing from the broader spirit and scope of the invention as set forth in the claims. Therefore, the specification and drawings should be considered illustrative rather than restrictive.

Claims

1. A valve bridge for use with an engine valve assembly of an internal combustion engine, the engine valve assembly including a plurality of engine valves, the internal combustion engine having a valve mechanism for transmitting motion from a motion source to the valve bridge, the valve mechanism including an elephant foot adapted to engage with the valve bridge to transmit motion from a rocker arm to the valve bridge, the valve bridge comprising: Central bridge housing; A locking assembly disposed in the central axle housing and having an elephant foot engagement surface, the locking assembly being adapted to selectively lock or allow movement of the elephant foot engagement surface relative to the central axle housing, thereby transmitting or absorbing movement; and The bridge also includes a control surface sized to disengage from the elephant foot during a controlled state in which the valve bridge remains aligned with and positioned to transmit valve actuation motion to the plurality of engine valves, and sized to contact the elephant foot when the bridge moves to an uncontrolled state in which the valve bridge moves away from and / or out of engagement with one or more of the plurality of engine valves.

2. The valve bridge of claim 1, wherein the control surface surrounds the elephant foot engagement surface.

3. The valve bridge of claim 1, wherein the control surface is defined by a collar extending around the elephant foot engagement surface.

4. The valve bridge according to claim 3, wherein the collar is circular.

5. The valve bridge of claim 1, wherein the elephant foot engagement surface is located on a plunger or piston assembly disposed in the central bridge housing.

6. The valve bridge of claim 1, wherein the control surface extends a distance from the central bridge housing such that when the locking assembly is locked, the bottom surface of the elephant foot is positioned above the end edge of the control surface.

7. The valve bridge of claim 1, wherein the elephant foot engagement surface is located on the plunger, the plunger being adapted to move a stroke length within the valve bridge in the unlocked state, wherein the control surface extends a distance such that the elephant foot can translate within the space defined by the control surface over the entire plunger stroke length.

8. The valve bridge of claim 1, further comprising a valve head recess for receiving a valve stem head, the valve head recess defining a valve stem seat, the valve head recess further comprising an introduction surface adapted to guide the valve stem seat and the valve stem head to be aligned when the bridge is in a controlled state.

9. The valve bridge according to claim 8, wherein the inlet surface is an inclined surface.

10. The valve bridge of claim 8, wherein the diameter of the introduction surface is configured to accommodate the maximum bridge jump displacement between the valve stem seat and the valve stem.

11. The valve bridge of claim 1, further comprising an extension disposed near the central bridge housing and having at least one extension control surface configured to restrict bridge movement by engaging with a valve spring assembly, thereby holding the bridge in a controlled state.

12. The valve bridge of claim 11, wherein the extension control surface is configured to engage with the valve spring.

13. The valve bridge of claim 11, wherein the extension control surface is configured to engage with the valve spring retainer.

14. The valve bridge of claim 11, wherein the extension control surface is configured not to contact the valve spring assembly when the valve bridge is in a controlled state, and wherein the extension control surface is configured to contact the valve spring assembly to retain the valve bridge.

15. The valve bridge according to claim 1, wherein the valve bridge further comprises a brake pin disposed in a brake pin hole in the valve bridge.

16. The valve bridge of claim 15, wherein the brake pin is configured to constrain the relative movement of the brake pin and the bridge to hold the valve bridge in a controlled state.

17. The valve bridge of claim 15, wherein the valve bridge further comprises a brake pin base receiver for receiving the base of the brake pin, wherein the brake pin base receiver and the brake pin base are configured to constrain relative movement of the brake pin base and the brake pin base receiver to hold the valve bridge in a controlled state.

18. The valve bridge of claim 1, further comprising a valve recess inlet ramp configured to capture the valve stem head at all valve bridge positions within the range of motion of the valve bridge defined by the control surface.

19. The valve bridge of claim 1, wherein the valve bridge has an extension adapted to engage with a valve spring and an extension control surface defining a range of motion of the valve bridge relative to at least two valve springs, and further includes a valve recess introduction ramp configured to capture the valve stem head at all valve bridge positions within the range of motion of the valve bridge defined by the extension control surface.

20. The valve bridge of claim 1, further comprising a brake pin adapted to constrain the movement of the valve bridge, and further comprising an introduction surface for guiding the valve bridge relative to the valve stem.

21. The valve bridge of claim 20, wherein the control surface includes a collar adapted to at least partially surround the elephant foot and constrain the movement of the valve bridge relative to the elephant foot.

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