CN115485463A

CN115485463A - Valve bridge system for resisting uncontrolled movement of valve bridge

Info

Publication number: CN115485463A
Application number: CN202180032404.7A
Authority: CN
Inventors: S·本; D·杨; G·S·罗伯茨; B·斯旺邦; J·D·巴尔特鲁基; J·曼德尔
Original assignee: Jacobs Vehicle Systems Inc
Current assignee: Jacobs Vehicle Systems Inc
Priority date: 2020-05-06
Filing date: 2021-05-06
Publication date: 2022-12-16
Also published as: EP4146919A1; BR112022022236A2; WO2021226636A1; KR20220164060A; JP2023523753A

Abstract

A valve bridge system includes a valve bridge body configured to extend between at least two engine valves of an internal combustion engine. The valve bridge body includes a through hole configured to align with a first engine valve and receive a bridge pin. The bridge pin boss has a through hole formed therein, has a longitudinal length, and terminates at an upper surface. The longitudinal length is configured such that the upper surface of the bridge pin boss contacts a surface of an auxiliary rocker arm to resist uncontrolled movement of the valve bridge when the valve bridge is in an uncontrolled state relative to the at least two engine valves.

Description

Valve bridge system for resisting uncontrolled movement of valve bridge

Technical Field

The present disclosure relates generally to valve actuation systems in internal combustion engines, and more particularly to valve bridge systems incorporating valve bridge guides for use in conjunction with such valve actuation systems.

Background

Valve actuation systems for internal combustion engines are known in the art. Such valve actuation systems typically include a valvetrain that, in turn, includes one or more components that transfer valve actuation motion from a valve actuation motion source (e.g., one or more cams) to the engine valves. An assembly commonly found in valvetrains is the so-called valve bridge, which incorporates a device that spans two or more engine valves associated with a given cylinder. In many cases, such a valve bridge allows another component of the valve train (e.g., a rocker arm) to simultaneously actuate two other engine valves that engage the valve bridge. Ideally, in operation, the opposing action of the force exerted by the motion transfer assembly (e.g., rocker arm) and by the engine valve spring ensures that the valve bridge remains in contact with both the motion transfer assembly and the engine valve (allowing for normal lash setting). In this manner, the valve bridge remains aligned with and positioned to transfer valve actuation motion to the engine valve at all times. 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.

Some valve actuation systems are configured to provide so-called auxiliary valve actuation motions, i.e., valve actuation motions other than those used to operate the engine in a positive power generation mode through combustion of fuel. In such valve actuation systems, the valve bridge may be configured to include a device or lost motion assembly that allows valve actuation motion to be transferred through the valve bridge to the engine valves, or to selectively "lost motion" in the event that such motion is not transferred through the valve bridge to the engine valves. Fig. 1 shows such a system described in U.S. patent application publication No. 2012/0024260, the teachings of which are incorporated herein by reference. In this case, the valve bridge 710 is provided with a lost motion assembly in the form of a locking mechanism. In the embodiment shown, the locking mechanism comprises a ball 740 that can be forced through an opening in the outer plunger 720 and into engagement with a recess 770 formed in the body of the valve bridge. In this state, ball 740 is prevented from disengaging notches 770 due to the outer diameter of inner plunger 760, thereby locking outer plunger 720 in a fixed relationship with respect to valve bridge 710. Thus, any valve actuation motion imparted to the outer plunger 720 by the rocker arm 200/400 is transferred 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 disengage 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 not be transferred to the engine valve. 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.

However, in systems of the type shown in fig. 1, there is the possibility of partial engagement of the locking mechanism. In this case, valve actuation motions may be initially applied to the engine valves to lift the engine valves off their seats. However, due to partial engagement of the locking mechanism, increased loads or vibrations in the valve actuation system cause the locking mechanism to quickly switch from a partially locked state to an unlocked state. When this occurs, the force provided by the valve actuation motion to open the engine valve is suddenly removed, allowing the engine valve to quickly accelerate to a closed position under the substantial force of the valve spring in an unrestricted manner. When the engine valve reaches a fully closed position (i.e., stops on a valve seat formed in the cylinder head), the momentum imparted on the valve bridge may cause the valve bridge to continue an uncontrolled trajectory in a direction generally away from the engine valve until striking a rocker arm or some other object. In fact, it is possible for the valve bridge to fall off either end of the engine valve, allowing the valve bridge to move away from the engine valve, resulting in engine damage. This type of movement is referred to as "uncontrolled movement" of the valve bridge, and as used herein, this condition of the valve bridge is referred to as the "uncontrolled condition" of the valve bridge relative to the engine valves. It is also known that uncontrolled states of the valve bridge occur as a result of overspeed operation of the internal combustion engine.

In view of this possibility of failure, a solution that prevents, minimizes or accommodates uncontrolled conditions of the valve bridge (regardless of the cause) would represent a welcome addition to the prior art.

Disclosure of Invention

The present disclosure describes a valve bridge system that overcomes the above-mentioned problems of prior art valve bridge systems. In a first principal embodiment, a valve bridge system includes a valve bridge configured to extend between at least two engine valves of an internal combustion engine. A valve bridge guide is operably connected to the valve bridge and includes a valve bridge control surface for selectively contacting at least one of the valve bridge or an engine valve assembly including at least two engine valves, at least two valve springs corresponding to the at least two engine valves, and at least two spring retainers corresponding to the at least two engine valves. In this embodiment, the valve bridge guide may be made of a moldable polymer. The valve bridge control surface is configured to avoid contact with the valve bridge or the engine valve assembly when the valve bridge is in a controlled state relative to the at least two engine valves, and is further configured to contact the valve bridge or the engine valve assembly to resist uncontrolled movement of the valve bridge when the valve bridge is in an uncontrolled state relative to the at least two engine valves. In an embodiment, the valve bridge guide is configured to extend between at least two valve springs, wherein the valve bridge control surface is at least one concave surface corresponding to at least one convex surface defined by at least two valve springs or at least two spring retainers, or a convex surface defined by a portion of said valve bridge. More specifically, each of the at least one recessed surfaces may be defined by opposing edges such that a line intersecting the opposing edges forms a cut line with respect to an outer diameter of a corresponding one of the at least two valve springs or the at least two spring retainers.

The valve bridge guide and the valve bridge may form a unitary structure, or the valve bridge guide may comprise one or more separate components operatively connected to the valve bridge. In an embodiment, the valve bridge guide comprises two guide members configured to engage opposite sides of the valve bridge, and may further comprise at least one fastener for operably coupling the two guide members together. The valve bridge guide may comprise an opening for receiving at least a portion of a valve bridge, and may further comprise at least two protruding members, each of which protrudes from the valve bridge guide towards the valve bridge and extends at least past a lower surface of the valve bridge facing the at least two engine valves. Further, the at least two protruding members may define a valve bridge control surface. Alternatively, each of the at least two protruding members may comprise an attachment surface for engaging a corresponding surface of the valve bridge.

In a second principal embodiment, a valve bridge system may include a valve bridge configured to extend between at least two engine valves of an internal combustion engine, the valve bridge including a lower surface facing the at least two engine valves and an upper surface opposite the lower surface. The system of this primary embodiment further includes a valve bridge guide having a first member retained in a first fixed position relative to the valve bridge, the first member including a first surface facing and a predetermined distance from the upper surface of the valve bridge when the at least two engine valves are in a closed condition. The predetermined distance is configured to prevent contact between the first surface and an upper surface of the valve bridge when the upper bridge body is in a controlled state relative to the at least two engine valves, and to allow contact between the first surface and the upper surface of the valve bridge to resist uncontrolled movement of the valve bridge when the valve bridge is in an uncontrolled state relative to the at least two engine valves. Where the valve bridge includes a receptacle that receives an engine valve end of one of the at least two engine valves, the predetermined distance may be less than a depth of the receptacle.

The first fixed position of the first member may be aligned with a first engine valve of the at least two engine valves that is furthest from a rocker shaft of the internal combustion engine. The valve bridge system may further comprise a second member retained in a second fixed position relative to the valve bridge, the second member comprising a second surface facing the upper surface of the valve bridge and spaced from the upper surface of the valve bridge by the predetermined distance. In this case, the second fixed position of the second member is aligned with a second engine valve of the at least two engine valves that is closest to a rocker shaft of the internal combustion engine. The first member may be configured to attach to a cylinder head of an internal combustion engine, while the second member may form a unitary structure with a rocker shaft base of the internal combustion engine.

In a further alternative of this second main embodiment, the valve bridge guide may further comprise a bridge pin arranged in one end of the valve bridge and aligned with an engine valve of the at least two engine valves. Alternatively, the first member of the valve bridge guide in this embodiment may comprise an arch configured for attachment to the cylinder head, extending between the at least two engine valves and over the upper surface of the valve bridge, the arch further comprising an opening formed therein, the opening being aligned with a portion of the valve bridge contacting the valvetrain assembly.

Drawings

The features described in this disclosure are set forth with particularity in the appended claims. These features and attendant advantages will become apparent from a consideration of the following detailed description when taken in conjunction with the accompanying drawings. One or more embodiments are now described, by way of example only, with reference to the accompanying drawings, in which like reference numerals represent like elements, and in which:

FIG. 1 is a cross-sectional view of a valve actuation system including a valve bridge having a locking mechanism according to the prior art;

FIGS. 2 and 3 are respective top and bottom isometric cross-sectional views of a first primary embodiment of a valve actuation system incorporating a valve bridge and a valve bridge guide according to the present disclosure;

FIG. 4 is a schematic diagram showing the relationship between a valve spring and a surface of a valve bridge guide according to the first main embodiment;

FIGS. 5 and 6 are respective isometric and cross-sectional views (along section line VI-VI) of a valve bridge and valve bridge guide according to a first variation of the first primary embodiment;

FIGS. 7 and 8 are respective isometric and cross-sectional views (along section line VIII-VIII) of a valve bridge and valve bridge guide according to a second variation of the first primary embodiment;

FIGS. 9 and 10 are respective isometric and cross-sectional views (along section line X-X) of a valve bridge and valve bridge guide according to a third variation of the first primary embodiment;

FIG. 11 is an isometric view of a valve bridge guide according to a fourth variation of the first primary embodiment;

FIG. 12 is an isometric view of a valve bridge and valve bridge guide according to a fifth variation of the first primary embodiment;

FIG. 13 is an isometric view of a valve bridge guide according to a sixth variation of the first primary embodiment;

figures 14 and 15 are respective isometric and sectional views of a valve bridge guide according to a seventh variant of the first main embodiment;

FIG. 16 is an isometric view of a valve bridge guide according to an eighth variation of the first primary embodiment;

FIG. 17 is an isometric view of a valve bridge guide according to a ninth variation of the first primary embodiment;

FIGS. 18 to 21 are respective isometric, side and front views of a valve bridge and valve bridge guide according to a second main embodiment;

FIG. 22 is a top isometric view of a valve bridge and valve bridge guide according to a first variation of the second main embodiment;

FIG. 23 is a cross-sectional view of a valve bridge according to the prior art;

FIG. 24 is a cross-sectional view of a valve bridge according to a third main embodiment;

FIG. 25 is a cross-sectional view of a valve bridge according to the fourth through sixth main embodiments;

FIGS. 26 to 28 are respective top isometric and sectional views of a valve bridge according to the seventh main embodiment;

FIG. 29 is a side view of a valve bridge according to the eighth main embodiment;

FIGS. 30 and 31 are respective isometric and sectional views of a valve bridge and bridge pin according to a ninth main embodiment;

FIG. 32 is a side partial cross-sectional view of a valve actuation system according to the prior art;

FIG. 33 is a top isometric view of the valve actuation system according to the tenth embodiment;

FIGS. 34 and 35 are respective top and bottom isometric views of a valve bridge and valve bridge guide according to an eleventh embodiment; and is

FIG. 36 is a top isometric view of the valve bridge and valve bridge guide of FIGS. 34 and 35 deployed in a valve actuation system.

Detailed Description

Fig. 2-36 illustrate various embodiments of valve bridge systems incorporating valve bridge guides according to the present disclosure. In all of the embodiments and variations shown in fig. 2 to 36, it is assumed that the valve bridge is of the type shown in fig. 1, i.e. the valve bridge has a locking mechanism of the general type shown in fig. 1 and described above.

Fig. 2 shows a first embodiment according to the present disclosure, in which an internal combustion engine 202 contains a pair of valve bridges 204, 212 for a single cylinder. In the illustrated embodiment, each

valve bridge

204, 212 actuates two corresponding engine valves, but it is possible that each valve bridge actuates more than two engine valves. As is known in the art, each valve bridge 204, 212 (or any other valve bridge shown and described herein) may actuate two engine valves of the same type, i.e., two intake valves or two exhaust valves. For ease of illustration, only the features and operation of the first valve actuation system according to the first embodiment are described, it being understood that the described features and operation apply equally to all valve bridges included in an internal combustion engine.

Thus, as shown, the first valve bridge 204 spans across a pair of engine valves (not visible in FIG. 2) in a conventional manner as is known in the art. Each engine valve has a

valve spring

208, 210 that biases its corresponding engine valve to a closed state (i.e., the engine valve head engages a valve seat formed in the cylinder head 230) and a

valve spring retainer

209, 211 that is attached to the stem of the engine valve. As further shown, the valve bridge system 202 further includes a valve bridge guide 206 that extends downward from the valve bridge 204 (i.e., in the direction of the cylinder head and away from the rocker arm 220) and between the valve springs 208, 210. In an embodiment, the distance that the valve bridge guide 206 extends between the valve springs 208, 219 is dictated, to a minimum, by the portion of the valve bridge 204 that surrounds the locking mechanism (e.g., see FIG. 1, the depth of the portion of the valve bridge that houses the plunger outer 720 and plunger outer spring 746). In the embodiment shown in FIG. 2, the valve bridge and valve bridge guide are formed as a unitary structure, i.e., not separate unitary parts, such that the locking mechanism is received within openings (best shown in FIG. 3) formed in valve bridge 204 and valve bridge guide 206. As described in more detail below, the valve bridge guide 206 includes at least one valve bridge control surface configured to interact with one or both of the valve springs 208, 210 or

valve spring retainers

209, 211 to prevent, minimize or at least accommodate uncontrolled movement of the valve bridge 204.

Fig. 3 illustrates a cross-sectional view of the valve spring guide 206 and the first valve spring 208 taken along section line III-III (shown in fig. 2). An opening 310 for receiving the locking mechanism is formed in the valve spring guide 206, and FIG. 3 further shows a valve stem 320 disposed within the corresponding valve spring 208. More specifically, fig. 3 shows two valve bridge control surfaces 402 defined by the valve bridge guide 206 such that the valve bridge control surfaces 402 conform to corresponding valve springs 306 (only one shown in fig. 3), i.e., the valve bridge control surfaces 402 are concave relative to the convex outer surfaces of the valve springs 208, 210. Although conforming, the valve bridge control surface 402 is configured such that during a controlled state of the valve bridge, the valve bridge control surface 402 (and thus the valve bridge guide 206) is able to avoid contact with its

corresponding valve spring

208, 210. The valve bridge control surface 402 may be configured as close as possible to the valve springs 208, 210 (within manufacturing tolerances) such that normal movement and vibration of the valve bridge 204, valve bridge guide 206 and valve springs 208, 210 is insufficient to cause contact between the valve bridge control surface 402 and the valve springs 208, 210. For example, as is known in the art, when a compression spring, such as the valve springs 208, 210, is deformed (i.e., compressed), the outer diameter of the spring will increase slightly. Thus, the valve bridge control surface 402 may be configured to account for the largest expected variation in spring diameter while remaining as close as possible to the valve springs 208, 210.

In some cases, it may not be desirable for the valve bridge guide 206 to contact the valve springs 208, 210, which would otherwise result in early degradation of the valve springs 208, 210. Accordingly, it may be desirable to alternatively configure the valve bridge control surface 402 to contact the

spring retainers

209, 211. To achieve this configuration, the

spring retainers

209, 211 may need to be sized to have an outer diameter that is greater than the outer diameter of the valve springs 28, 210. In this case, the valve bridge control surface 402 is instead defined by the valve bridge guide 206 such that the valve bridge control surface 402 conforms to the

corresponding spring retainer

209, 211, i.e. the valve bridge control surface 402 is concave relative to the convex outer surface of the

spring retainer

209, 211. Again, such a concavity is configured such that the valve bridge control surface 402 can avoid contact with its corresponding

spring retainer

209, 211 during a controlled state of the valve bridge, and is further configured as close as possible to the valve springs 208, 210 (within manufacturing tolerances) such that normal movement and vibration of the valve bridge 204, valve bridge guide 206 and valve springs 208, 210 is insufficient to cause contact between the valve bridge control surface 402 and the

spring retainers

209, 211.

While the various figures shown and described in this disclosure show at least two concave valve bridge control surfaces 402, this is not a necessary requirement. For example, a single such valve bridge control surface 402 may be employed if used in combination with another feature that provides additional control over the uncontrolled movement of the valve bridge 204. For example, where the valve bridge 204 is equipped with a bridge pin (see, e.g., element 2102 of FIG. 21), a single valve bridge control surface 402 and bridge pin combination may be sufficient.

The configuration of the valve bridge control surface 402 according to a preferred embodiment is further described with respect to fig. 4, which schematically illustrates the valve bridge guide 206 and the valve spring 208 in an enlarged form in fig. 4. (alternatively, as noted above, the valve spring 208 shown in FIG. 4 may be considered a spring retainer, but for ease of description only the valve spring 208 is described herein.) As shown, the valve bridge guide 206 includes a concave valve bridge control surface 402 that approximates an outer diameter 408 of the valve spring 208. In practice, the clearance between the valve bridge control surface 402 and the outer diameter 408 is based in part on manufacturing tolerances of the valve springs 208, 210 (or spring retainers 209, 211) and the valve bridge 204. In addition, the clearance is based on the clearance of the engine valve end in a receptacle formed in the valve bridge 204 for receiving the engine valve tip. For example, if valve bridge 204 is allowed to move ± 0.25mm, the clearance between valve spring 208 and valve bridge control surface 402 should be greater than the tolerance of the parts plus the allowed 0.25mm of play. Furthermore, the chamfer at the bottom of valve bridge 204 should be large enough so that if valve bridge 204 experiences uncontrolled movement over the entire clearance with the valve spring or spring retainer, valve bridge 204 can still reposition itself on the engine valve tip.

As further shown in FIG. 4, the circumferential length of the concave valve bridge control surface 402 (relative to the outer diameter 408 of the spring 208) is defined by opposing

edges

404, 406. In the preferred embodiment, the opposing

edges

404, 406 are spaced apart to such an extent that when the valve bridge guide 206 is positioned during the controlled state of the valve bridge 204, a line 410 intersecting the opposing

edges

404, 406 as shown forms a cut line at least with respect to the outer diameter 408 of the valve spring 208. Configured in this manner, it will be appreciated that if large enough, movement of the valve bridge guide 206 in either direction indicated by line 410 (such as may occur during an uncontrolled condition of the valve bridge 204) will result in contact between the concave valve bridge control surface 402 and the spring outer diameter 408 such that the valve bridge guide 206 will deflect generally in a direction away from the valve spring 208 and toward the other valve spring 210. More generally, any rotational movement of valve bridge 204 about the axis of the locking mechanism centerline is also limited to lateral movement in two horizontal planes. Accordingly, and referring back to FIGS. 2 and 3, during an uncontrolled condition of valve bridge 204, such operation of concave valve bridge control surface 402 will tend to realign valve bridge guide 206 itself with valve springs 208, 210, effectively inhibiting or even eliminating any uncontrolled movement of valve bridge 204 and valve bridge guide 206.

Referring now to fig. 5 and 6, a first variation of valve bridge guide 502 comprises a separate piece from valve bridge 204 having valve bridge control surface 402 formed on a lateral side thereof as shown. The valve bridge 204 is also shown having a receiving portion 614 for receiving a valve stem end of an engine valve, as is known in the art and described above. In this embodiment (and the further embodiments shown in fig. 7-13), the valve bridge guide 502 may be made of the same material as the valve bridge 204 (e.g., steel), but in a preferred embodiment the valve bridge guide 502 is formed of a lighter, sturdy material that is still softer than the valve bridge springs 208, 201 (or spring retainers 209, 211) to avoid damage or breakage. For example, suitable moldable polymers known in the art may be used for this purpose. Other types of materials for manufacturing the valve bridge guide will be apparent to those skilled in the art.

Regardless, as further shown, valve bridge guide 502 has an opening or bore 602 formed therein that is configured to snugly receive a portion 604 of valve bridge 204. As shown, a portion 604 of valve bridge 204 received by valve bridge guide 502 preferably houses at least some locking mechanism 606. As further shown, in this embodiment, both the valve bridge guide 502 and the portion 604 of the valve bridge 204 include fastener receiving features 504, 608. In this embodiment, the fastener receiving feature 504 of the valve bridge guide comprises a bore that intersects an opening 602 formed in the valve bridge guide 502. Thus, where the hole intersects the opening 602, the fastener receiving feature 504 substantially comprises a channel having a semi-circular cross-section formed in a sidewall of the opening 602. In a complementary manner, fastener receiving feature 608 of portion 604 of valve bridge 204 is also formed as a semi-circular channel in the outer sidewall surface of portion 604. When aligned, these respective fastener receiving features 504, 608 may receive

fasteners

610, 612 such that valve bridge guide 502 is operably connected to portion 604 of valve bridge 204. For example, in the illustrated embodiment, the fastener 612 may comprise a split dowel as shown, but those skilled in the art will recognize that other types of fasteners, such as screws, may be equivalently employed. In this manner, valve bridge guide 502 is relatively rigidly attached to valve bridge 204 such that they move in unison. As an alternative to the fastener embodiments described above, valve bridge guide 502 (or other embodiments of valve bridge guides shown in fig. 7-13) may alternatively be securely attached to valve bridge 204 using a suitably strong and durable epoxy or similar adhesive. Furthermore, a combination of these techniques may also be used as a matter of design choice.

Referring now to fig. 7 and 8, a second variation of a valve bridge guide 702 is substantially similar to the valve bridge 502 of fig. 5 and 6 in that it comprises a separate body from the valve bridge 204 having a valve bridge control surface 402 formed on a lateral side thereof as shown. However, in this embodiment, the valve bridge guide 702 includes one or more teeth 802 extending inwardly from a sidewall surface of the opening 602 and configured to engage a notch 804 formed in an outer sidewall surface of the portion 604 of the valve bridge 204. For example, recess 804 may comprise an annular groove or channel formed in the sidewall of portion 604 of valve bridge 204. When the teeth 802 engage the notches 804, the valve bridge guide 702 is again operatively connected to the valve bridge in a relatively rigid manner such that the valve bridge guide 702 and the valve bridge 204 move in unison. It should be noted that in this embodiment, the arrangement of one or more teeth 802 and notches 804 may be equivalently reversed, i.e., teeth 802 may be formed on the outer sidewall surface of portion 604 of valve bridge 204 and notches 804 may be formed on the inner sidewall surface of opening 602.

As further shown in FIG. 7, the valve bridge guide 702 may include at least two protruding

members

704, 706 that protrude from the valve bridge guide 702 toward the valve bridge 204. As shown in FIG. 8, valve bridge 204 has a lower surface 806, and in embodiments, protruding

members

704, 706 extend at least beyond lower surface 806 of valve bridge 204. In this embodiment, at least two protruding

members

704, 706 facilitate the orientation of valve bridge guide 702 on valve bridge 204, thereby preventing valve bridge 204 from rotating relative to valve bridge guide 702. In this manner, the at least two protruding

members

704, 706 further facilitate alignment of the valve bridge control surface 402 with the valve springs 208, 210 or

spring retainers

209, 211.

Referring now to fig. 9 and 10, a third variation of valve bridge guide 902 is shown, in which valve bridge guide 902 is again formed as a separate entity from valve bridge 204, having valve bridge control surface 402 formed on a lateral side thereof, as shown. However, in this embodiment, the valve bridge guide 902 has a side opening 904 with a cantilever latch or clip 906 disposed therein. As shown, clips 906 are configured to engage corresponding notches 1002 formed in the outer sidewall surface of portion 604 of valve bridge 204. For example, recess 1002 may again comprise an annular groove or channel formed in the sidewall of portion 604 of valve bridge 204. When the clips 906 engage the notches 804, the valve bridge guide 702 is again operatively connected to the valve bridge in a relatively rigid manner such that the valve bridge guide 902 and the valve bridge 204 move in unison. As shown, the valve bridge guide 902 may further include an auxiliary latching surface 908 configured to engage a corresponding auxiliary notch 1004 formed in the portion 604 of the valve bridge 204. By providing multiple latch pairs 906, 1002/908, 1004, the stability of the valve bridge guide 902 relative to the valve bridge 204 may be improved.

Referring now to FIG. 11, a fourth variation of the valve bridge guide 1102 is shown. In this variation, the valve bridge guide 1102 is integral disposed between the

spring retainers

209, 211 and the valve bridge 204.

Notches

1104, 1106 are provided to allow the valve bridge guide 1102 to be positioned relative to the end of the engine valve. Additionally, a central opening 1107 may be provided that allows a portion of valve bridge 204 (e.g., the portion that houses the locking mechanism shown in FIG. 1) to extend through valve guide 1102. Similar to the embodiment of fig. 7 and 8, the valve bridge guide 1102 includes at least two projecting members in the form of

side walls

1108, 1110 that define a channel 1116, which in turn is configured to receive the valve bridge 204. In this embodiment, the

inner surfaces

1112, 1114 of the

side walls

1108, 1110 that rise above the valve bridge 204 serve as valve bridge control surfaces that prevent lateral movement or rotation of the valve bridge 204 that may result during an uncontrolled condition of the valve bridge 204. Further, although not shown in FIG. 11, an additional valve bridge control surface 402 may optionally be provided on the lower portion 1118 of valve bridge guide 1102 to prevent tilting of valve bridge 204, as described above. To the extent that valve bridge guide 1102 is securely attached to valve bridge 204 (using any of the techniques described above), any excessive lift of valve bridge 204 (e.g., away from the engine valve end) will cause a similar lift in valve bridge guide 1102, which again resists uncontrolled movement and allows valve bridge 204 to again stabilize back onto the engine valve end.

Referring now to fig. 12, a fifth variation of the valve bridge guide 1202 is substantially similar to the valve bridge 502 of fig. 5 and 6 in that it comprises a separate entity from the valve bridge 204 having the valve bridge control surface 402 formed on a lateral side thereof as shown. As further shown, and similar to the second variation shown in fig. 7 and 8, this embodiment of the valve bridge guide 1202 further includes a plurality of protruding members 1204-1212 extending upwardly from the body of the valve bridge guide 1202 for similar purposes as described above. Additionally, as shown, each of the protruding members 1204-1212 includes an attachment surface 1214, 1216 (only two shown in fig. 12) in the form of inwardly extending

fingers

1214, 1216 disposed at the terminal ends of the protruding members 1204-1212. The attachment surface so defined is configured to engage a corresponding surface 1220 of valve bridge 204, in this case, the upper surface of valve bridge 204. In this manner, valve bridge guide 1202 is retained on valve bridge 204. Alternatively, and similar to the embodiment of fig. 9 and 10,

fingers

1214, 1216 may instead engage notches or similar features formed in the lateral sides of valve bridge 204.

FIG. 13 shows a sixth variation of the first embodiment, in which a valve bridge guide 1302 is formed from two

guide members

1304, 1306 that are configured to engage opposite sides of a valve bridge. As in other embodiments, each of the

guide members

1304, 1306 defines a valve bridge control surface 402 as described above. Further, each of

guide members

1304, 1306 defines a first opening 1308 (only one shown) configured to receive portion 604 (not shown) of valve bridge 204. As further shown, each of the

guide members

1304, 1306 also includes a channel or second opening 1310 configured to receive one of the arms of the valve bridge 204 (i.e., the portion of the valve bridge that extends from the center of the valve bridge to one of the engine valves). Further, one of the

guide members

1304, 1306 includes a fastener in the form of complementary first latch 1312 and first latch notch 1314 and second latch 1316 and second latch notch 1318 so that the

guide members

1304, 1306 may be securely connected to each other. Alternatively, any of the attachment mechanisms described above (dowel pins, epoxy, etc.) may be used as a "fastener" for this purpose. When connected,

guide members

1304, 1306 collectively define a valve bridge guide 1302 that is held in place relative to valve bridge 204 by virtue of second opening 1310 surrounding the arms of valve bridge 204.

FIGS. 14 and 15 show a seventh variation of the first primary embodiment in which the valve bridge guide 1402 is formed as a stamped metal plate structure having a horizontal surface 1404 and a continuous sidewall 1406 extending downwardly therefrom. In this variation, similar to the embodiment shown in FIG. 11, the valve bridge guide 1402 is designed to rest on top of the spring retainers 209, 211 (FIG. 15) and below the valve bridge 204 (not shown). In fig. 15, the side wall 1406 is shown extending past the

spring retainers

209, 211 and the initial portions of the valve springs 208, 210. In an embodiment, the extent of the side wall 1406 is such that the valve bridge guide 1402 cannot lift completely off the

spring retainers

209, 211 despite any vertical displacement being applied to the valve bridge 204. In addition to the central opening 1406 which allows a portion of the valve bridge 204 to pass through, the valve bridge guide 1402 also contains a plurality of protruding members 1408-1416 (four shown in the example shown) similar to those shown in FIGS. 7, 8, 11 and 12. As shown, the protruding members 1408-1416 are formed as upwardly curved portions of the horizontal surface 1404, which results in

openings

1426, 1428 that allow the end of the engine valve 1502 to pass therethrough. In this case, projecting members 1408 to 1416 again define valve

bridge control surfaces

1422, 1424 for resisting uncontrolled movement of valve bridge 204.

Fig. 16 shows an isometric view of an eighth variation of the first primary embodiment, in which the valve bridge guide 1602 includes two guide members 1603 (only one shown) configured to engage opposite sides of the valve bridge 204 (not shown). Each guide member 1603 is formed as a stamped sheet metal structure having a horizontal surface 1604 and continuous side walls 1606 extending downward therefrom, similar to the embodiment of fig. 14 and 15, but configured to rest atop only a single spring retainer 209. Likewise, each guide member 1603 includes a plurality of upwardly extending

protruding members

1608, 1610 and a central opening 1612 for passage of an engine valve end, wherein each of the protruding

members

1608, 1610 defines a valve bridge control surface 1614 for resisting uncontrolled movement of the valve bridge 204.

Similar to the embodiment of FIG. 16, the embodiment shown in FIG. 17 includes a valve bridge guide 1702 comprising a pair of guide members 1703 configured to rest atop the

separate spring retainers

209, 211. In this case, formed from a moldable polymer, each guide member 1703 includes a horizontal surface 1704 and a continuous sidewall 1706 extending downward therefrom, similar to the embodiment of fig. 14 and 15, but configured to rest atop only a single spring retainer 209, as in the embodiment of fig. 16. Likewise, each guide member 1603 includes a plurality of upwardly extending projecting

members

1708, 1710 and a central opening 1712 for passage of an engine valve end, wherein each of the projecting

members

1708, 1710 defines a valve bridge control surface 1614 for resisting uncontrolled movement of the valve bridge 204. In this case, however, each guide member 1703 is also provided with a lateral concave valve bridge control surface 402 as described above. In this case, however, the transverse concave valve bridge control surface 402 is not configured to conform to the outer surface of the valve springs 208, 210, but rather to conform to the portion of the valve bridge 204 extending downwardly between the valve springs 208, 210 and housing the locking mechanism, as described and illustrated above with respect to FIG. 1.

Referring now to fig. 18-21, a second main embodiment according to the present disclosure is shown, in which an internal combustion engine 202 incorporates a pair of valve bridges 204, 212 for a single cylinder. In the illustrated embodiment, each

valve bridge

204, 212 actuates two corresponding engine valves, although each valve bridge may again actuate more than two engine valves. In the illustrated embodiment, the first valve bridge 204 spans a pair of engine valves in a conventional manner as is known in the art. Each engine valve has a

valve spring

208, 210 biasing its corresponding engine valve to a closed state and a

valve spring retainer

209, 211 attached to the stem of the engine valve. As best shown in fig. 19, the valve bridge 204 includes a lower surface 1902 that faces the engine valve and an upper surface 1904 opposite the lower surface 1902.

As further shown in this second principal embodiment, the valve bridge system further includes a valve bridge guide in the form of a first member 1802 having a first surface 1906 facing the upper surface of valve bridge 204. First member 1802 is held in a first fixed position relative to valve bridge 204 using suitable fasteners 1806 (e.g., bolts or similar fixed structures threaded into the cylinder head). In particular, the first fixed position maintains the first member at a predetermined distance 1908 from the upper surface of the valve bridge 204 when at least two valve bridges are maintained in the closed state. Additionally, as shown, the first fixed position of the first member 1802 is aligned with a first engine valve of the at least two engine valves, wherein the first engine valve is furthest from a rocker shaft 1808 of the internal combustion engine 202. As shown, the first member 1802 may be configured such that it is aligned with a first engine valve as described for more than one

valve bridge

204, 212. Furthermore, the first member 1802 may also extend across a valve bridge for multiple cylinders of an internal combustion engine in this regard, or may comprise multiple such first members 1802, wherein the configuration of the cylinders prevents the use of a single first member 1802.

In this embodiment, the predetermined distance 1908 between the first member 1802 and the upper surface 1904 of the valve bridge 204 is preferably sufficient to prevent contact between the first surface 1906 of the first member 1802 and the upper surface 1904 of the valve bridge 204 when the valve bridge 204 is in a controlled state relative to the at least two engine valves, and to allow contact between the first surface 1906 and the upper surface 1904 when the valve bridge 204 is in an uncontrolled state relative to the at least two engine valves, so as to resist uncontrolled movement of the valve bridge 204. As used herein, uncontrolled movement of the valve bridge 204 is resisted to the extent that, when operating in a controlled state, any of the disclosed valve bridge guides resist movement of the valve bridge outside of its normal range of movement. Thus, while the variations of the first embodiment shown in fig. 2-12 oppose movement that would result in tilting or rotation of the valve bridge 204 relative to the engine valve, the first member 1802 opposes excessive vertical displacement of the valve bridge 204 relative to the engine valve, and in particular prevents complete disengagement of the valve bridge 204 from the engine valve. By defining a predetermined distance 1908 relative to the closed position of the engine valve, contact between valve bridge 204 and first member 1802 is avoided during controlled operation of valve bridge 204. However, by further defining predetermined distance 1908 to be sufficiently small, a desired resistance to uncontrolled movement of valve bridge 204 may be provided. In one embodiment, the predetermined distance 1908 may be based on a depth 2002 of a receptacle 2004 provided by the

valve bridge

204, 212 to engage a valve tip 2006 of an engine valve (fig. 20). In particular, the predetermined distance 1908 may be selected to be less than the depth 2002 of the receptacle 2004. In this way,

valve bridge

204, 212, if operated in an uncontrolled state, will contact first member 1802 before

valve bridge

204, 212 can travel a distance beyond depth 2002 of receiver 2004, which may otherwise result in

valve bridge

204, 212 disengaging from valve end 2006. Furthermore, it is known in some forms of engine brakes to actuate only a single inboard engine valve (i.e., closest to the rocker shaft), which may raise the portion of the valve bridge that engages the outboard engine valve (i.e., the portion furthest from the rocker shaft) slightly upward, for example, by about 1mm to 2mm. Therefore, the predetermined distance 1908 should be selected to accommodate the possibility of avoiding undesired contact with the valve bridge 204. In addition, normal wear of the engine valve seat may cause the engine valve tip to lift upward over time, and the predetermined distance 1908 should also account for this possibility.

In this second embodiment, the valve bridge guide may further comprise a second member 1804 retained in a second fixed position relative to the valve bridge 204 and having a second surface 1910 facing the upper surface 1904 of the valve bridge 204. As with the first member 1802, the second surface 1910 remains at a predetermined distance 1908 from the upper surface 1904 for the same reasons described above. In an embodiment, the second fixed position of the second member 1804 is aligned with a second of the at least two engine valves, wherein the second engine valve is closest to the rocker shaft 1808. Further, as best shown in fig. 18 and 19, the second member 1804 may be formed as a unitary structure with the rocker arm base 1810. In this manner, the first member 1802 and the second member 1808 may be separately aligned with different engine valves and at the same predetermined distance 1908 from the upper surface 1904, thereby acting as a valve bridge guide to provide uniform resistance to uncontrolled movement.

As is known in the art, some valve actuation systems include an auxiliary motion source and a valvetrain that provide auxiliary motion to individual engine valves despite the presence of the valve bridge 212. This is accomplished by using a bridge pin 2102, as is known in the art, to allow for auxiliary valve actuation motions to be applied to a single engine valve, and primary valve actuation motions to also be applied to a single engine valve via the valve bridge 212. In this case, the presence of the bridge pin 712 through the valve bridge 212 effectively acts as a second member defining a valve bridge guide. That is, if the valve bridge 212 is operating in an uncontrolled state, the presence of the bridge pin 712 (operatively connected to both the auxiliary rocker arm 2104 and the single engine valve) will operate to restrict the valve bridge 212 to only sliding movement relative to the bridge pin 712. In such a case, the presence of the auxiliary rocker arm 2104 (or other auxiliary valve train component) will operate to prevent the valve bridge 212 from exiting the bridge pin 2102. Also, where the first member 1802 is provided (as shown), the combined operation of the first and second members will resist uncontrolled movement, particularly upward movement, of the valve bridge 212.

Fig. 22 shows a first variant of the second embodiment, in which the valve bridge guide comprises a first member 2202 formed as a three-sided "strip". Similar to the embodiment of fig. 18-21, the variation shown in fig. 22 resists uncontrolled movement by placing the first member 2202 in contact with the upper surface 1904 of the valve bridge. In this embodiment, the first member 2202 may comprise a metal plate or similar material having two substantially perpendicular elongated sides 2204 (one shown in fig. 22) extending from above the valve bridge 214 to the base of the engine valve springs 208, 210, with each of the elongated sides 2204 mounted to the cylinder head 230. A substantially horizontal third side 2206 of the first member 2202 connects the first and second elongated sides 2204 at a top normal resting point of the valve bridge 214 (i.e., when the engine valve is fully closed) and above an upper surface 1904 of the valve 214. As with the embodiment of fig. 18-21, third side 2206 is preferably held in a fixed position at a predetermined distance 1908 (not shown in fig. 22) from upper surface 1904. As further shown, the third side 2206 includes an opening 2210 that allows a portion of the valve bridge 214 (e.g., see fig. 1, outer plunger 720/cap 730) to contact the rocker arm 2212, as shown. In this variation, displacement of valve bridge 204 is limited by third side 2206 of first member 2202 and opening 2206 formed therein.

FIG. 23 is a cross-sectional view of a valve bridge illustrating the disadvantages of the prior art system. In particular, fig. 23 shows a valve bridge having a valve bridge body 2302 that spans two engine valve stems 2304, 2306. As shown, the first engine valve 2306 is actuated by the auxiliary rocker arm 2312 via a bridge pin 2308 that receives a stem of the first engine valve 2306. In turn, the bridge pin 2308 is received in a through hole 2310 formed in the valve bridge body 2302 and aligned with the first engine valve 2306, allowing the bridge pin 2308 to contact the auxiliary rocker arm 2312. Additionally, the valve bridge body 2302 includes a receptacle 2314 that is aligned with the second engine valve 2304 and configured to receive a stem of the second engine valve 2304. In fig. 23, the valve bridge 2302 is in an uncontrolled state as depicted because the receiver 2314 loses contact with the second engine valve 2304. This stems from the fact that: no surface is provided to inhibit the valve bridge 2302 from traveling upward during an uncontrolled condition.

FIG. 24 shows a valve bridge according to a third main embodiment, showing a valve bridge substantially similar to the one depicted in FIG. 23. In this case, however, the valve bridge also includes a bridge pin boss 2402 having a through hole 2404 formed therein and having a greater longitudinal length (or height) than the embodiment shown in fig. 23. Thus, an upper surface 2406 of the bridge pin boss 2402 is closer to a lower surface 2408 of the auxiliary rocker arm 2312 (e.g., a lower surface of an actuator in the depicted embodiment). Thus, when the valve bridge is in an uncontrolled state, causing upward movement of the valve bridge body 2302, the upper surface 2406 of the bridge pin boss 2402 will contact the lower surface 2408 of the auxiliary rocker arm 2312 before the valve bridge body 2302 has had a chance to completely disengage the valve stem. This is illustrated in fig. 24, where contact between the upper surface 2406 and the lower surface 2408 prevents the receiver 2410 from completely disengaging from the stem of the second engine valve 2304.

It should also be appreciated that a similar upper surface of the portion of the valve bridge body 2302 that is aligned with the primary rocker arm 2412 may also be configured in a manner similar to the upper surface 2406 of the bridge pin boss 2402. In such a case, the height of the valve bridge body 2302, which is aligned with the primary rocker arm 2412, may be similarly increased such that an upper surface 2411 of the valve bridge body 2302 may contact the primary rocker arm 2412 (e.g., a lower surface of a swivel foot in the depicted embodiment) during uncontrolled movement of the valve bridge body 2302. In this case, however, the height of the upper surface 2411 must be selected so as not to interfere with the ability of the collapsing mechanism 2412 to fully absorb any valve actuation motion provided by the primary rocker arm 2412. In other words, the upper surface 2411 should not increase to a point of contact with the primary rocker arm 2412 during a controlled state (or controlled movement) of the valve bridge body 2302 and when the collapsing mechanism 2414 absorbs a primary valve event.

Referring now to fig. 25, there is shown a valve bridge according to the fourth through sixth main embodiments. In particular, FIG. 25 also shows a valve bridge similar in construction to the valve bridge shown in FIG. 23. The fourth primary embodiment relates to the feature of clearance between the inner diameter of the through bore 2502 and the outer diameter of the bridge pin 2504. In particular, because the clearance between the through-hole and the bridge pin is tightly controlled and minimized, the occurrence of uncontrolled movement will cause the valve bridge body 2302 to "pinch" (or seize) with the bridge pin 2504. This is illustrated in fig. 25 by the contact point 2505 between the through hole 2502 and the bridge pin 2504. In turn, this clamping dampens any further travel of the valve bridge body 2302, thereby tending to keep the valve bridge body 2302 aligned with the engine valve.

Fig. 25 further illustrates a fifth primary embodiment, depicting an increased radius spring retainer 2506 (relative to the radius of a typical spring retainer 2510, i.e., comparable to the radius of a valve spring (not shown)). In this embodiment, the increased radius spring retainer 2506 allows the portion 2508 of the valve bridge body 2302 that extends between the engine valve stem to more quickly contact the increased radius spring retainer 2506 at 2511 during uncontrolled movement (particularly rotation of the valve bridge body 2302), thereby resisting further rotation of the valve bridge body 2302.

Additionally, FIG. 25 further illustrates a sixth primary embodiment showing an extended valve stem feature. In the illustrated embodiment, the extend valve stem feature takes the form of a bridge pin 2512 that resides in the second through hole 2518. As shown, the bridge pin 2512 runs freely up and down on the engine valve stem 2514. In this case, when the valve bridge body 2302 is in an uncontrolled state, the bridge pin 2512 is free to travel upward with the valve bridge body 2302. As long as the bridge pin 2512 remains seated on the engine valve stem 2514, the bridge pin 2512 keeps the valve bridge body 2302 aligned with the engine valve stems 2514, 2516 despite uncontrolled movement of the bridge pin 2512 and the valve bridge body 2302. As shown, the same principles of controlled movement on the engine valve stem 2516 may be equally applied to the bridge pin 2504 aligned with the auxiliary rocker arm. In this embodiment, it may be desirable for either or both of the engine valve stems 2514, 2516 to have a higher extension than the

spring retainers

2506, 2512, for example, up to 10mm compared to a more typical length of 2mm to 3 mm.

Fig. 26 to 28 show a valve bridge according to a seventh main embodiment. According to a typical valve bridge, the illustrated valve bridge includes a valve bridge body 2602 spanning at least two

engine valves

2604, 2606. In this embodiment, slots 2608 are formed in those portions of the valve bridge body 2602 that are configured to contact stems of the

engine valves

2604, 2606. In particular, as best shown in fig. 28, the slot 2608 may comprise a laterally extending slot that transversely intersects a longitudinal axis 2806 of the receiver 2802 and the engine valve stem 2604 (only one shown in fig. 28). When the engine valve stem 2604 is aligned with and inserted into a corresponding receiver 2802, the annular channel 2804 formed in the engine valve stem 2604 is aligned with the slot 2608. The C-clip 2702 is inserted into the slot 2608 and engages the annular channel 2804 such that the C-clip 2702 is retained on the engine valve stem 2604. Once retained on the engine valve stem 2604, further engagement of the C-clip 2702 with the slot 2608 allows the C-clip 2702 to resist disengagement of the engine valve stem 2604 from the receiver 2802, for example, during uncontrolled movement of the valve bridge body 2602. Although the slot 2608 is shown in fig. 26-28 as extending laterally away from the valve bridge body 2602, this is not a requirement. For example, the slot 2608 may alternatively extend perpendicularly from the plane of fig. 28, i.e., perpendicular to the longitudinal axis of the valve bridge body and perpendicular to the longitudinal axis 2806 of the engine valve stems 2604, 2606.

FIG. 29 is a side view of a valve bridge according to the eighth main embodiment. In this embodiment, the valve bridge body 2902 includes a protrusion 2904 that extends downward from a lower surface 2908 of the valve body 2902 and is positioned between at least two engine valve stems (not shown). As further shown, the protrusion 2904 further includes at least one hook feature 2906 (only one shown) extending below and toward the at least one spring retainer 2910 away from the protrusion 2904 such that the hook or latch feature 2906 extends past an outer circumference of the at least one spring retainer 2910. When the valve bridge body 2902 is in an uncontrolled state, the hook-like feature 2906 will contact the underside 2912 of the valve spring retainer 2910 and prevent the valve bridge body 2902 from separating from the engine valve stem to the point where the valve bridge body is completely disengaged from the engine valve stem. Like the fifth embodiment described above with respect to fig. 25, the increased radius spring retainer 2910 may provide a protruding edge of material that extends beyond the outer circumference of the corresponding valve spring 2914. In this manner, the hook feature 2906 is better able to engage the spring retainer 2910 and thereby better ensure resistance to valve bridge disengagement.

As further shown in fig. 29, the peripheral shape 2914 of the projection 2904 is configured to allow the valve bridge body 2902 to move downward on one of the engine valves (rightmost, as depicted in fig. 29, as in the case of an auxiliary valve actuation motion) and to tilt without contacting the

springs

2914, 2918. Based on the configuration shown, installation of the valve bridge is facilitated by first installing the left side, and then rotating the valve bridge down onto the rightmost engine valve stem (and corresponding bridge pin 2920). Although the bridge pin 2920 is secured by a separate auxiliary rocker arm or its integrated actuator piston (not shown), the bridge cannot be removed due to the latching effect of the hook feature 2906.

FIGS. 30 and 31 show a valve bridge and bridge pin according to a ninth main embodiment. In this embodiment, the valve bridge body 3002 includes open laterally extending

slots

3004, 3006 configured to receive corresponding

bridge pins

3008, 3010 between

respective arms

3022, 3024 defined by the

slots

3004, 3006 extending into the valve bridge body 3002. As best shown in fig. 31, each

bridge pin

3008, 3010 has a receiving portion 3102 formed therein and configured to receive a corresponding engine valve stem 3012. As shown, each of the bridge pins 3008, 3010 has a spool-like shape that contains a barrel 3016 and an increased diameter (relative to the barrel 3016)

end cap

3018, 3020.

Slots

3004, 3006 are configured such that

arms

3022, 3024 maintain a relatively close clearance from barrel 3016 of their

respective bridge pins

3008, 3010. On the other hand,

slots

3004, 3006 are configured such that

arms

3022, 3024 will be in contact with

end caps

3018, 3020. In this manner, vertical movement of

bridge pins

3008, 3010 is limited by spacing 3104 between the upper (and/or lower) surfaces of

arms

3022, 3024 and the complementary surfaces defined by

end caps

3018, 3020. In this way, if the valve bridge body 3002 experiences uncontrolled movement, the restriction placed on the valve bridge body 3002 by the bridge pins 3008, 3010 prevents disengagement from the engine valve stems 3012, 3014. It should be noted that, like the third primary embodiment shown in FIG. 24, the upper surface 3026 of the valve bridge body 3002 may be configured such that the spacing between the upper surface 3026 and the end cap 3010 is configured to even further limit the upward travel of the valve bridge body 3002.

Fig. 32 shows a valve actuation system according to the prior art. In particular, valve actuation systems are known in which a collapsing mechanism similar to that shown in fig. 1 is deployed in a rocker arm 3202 or push rod 3204, rather than in a valve bridge 3206 as depicted in many of the previously described embodiments. As is known in the art, the rocker arm 3202 engages well on the rocker shaft 3208, however, such valve actuation systems provide the valve bridge 3206 with an opportunity to enter an uncontrolled state if excessive lash is formed in the valve train. For example, a sudden collapse in pushrod 3204 may allow the rocker arm to rotate backward (i.e., toward pushrod 3204) equal to the suddenly eliminated valve lift. If the valve lift thus lost is relatively high (e.g., 14mm in some systems), the sudden backward rotation of the rocker arm 3202 may cause the rocker arm 3202 to strike the valve cover 3210 or other object. Because the rocker arm 3202 typically relies on retaining the valve bridge 3206 in engagement with the engine valve stem, the combination of the sudden rearward rotation of the rocker arm 3202 and the rapid acceleration of the valve bridge 3206 under the influence of the valve spring will cause the valve bridge to move in an uncontrolled manner, resulting in disengagement.

To prevent the valve bridge 3206 from disengaging in such a situation, a stop may be provided to prevent over-rotation of the rocker arm 3202 that would otherwise allow the valve bridge 3206 to come out. An example of this is shown in fig. 33, where a rigid or fixed stop 3302 is deployed to prevent the rocker arm 3202 from rotating rearward. In the illustrated embodiment, the fixed stop 3302 is rigidly attached to the rocker arm shaft 3208 and, in this example, includes vertical 3304 and horizontal 3306 surfaces that are configured to engage surfaces of the rocker arm 3202 to prevent over-rotation thereof. The fixed stop 3302 is configured such that the vertical surface 3304 and the horizontal surface 3306 do not interfere with the normal reciprocation (i.e., are in a controlled state) of the rocker arm 3202. However, the fixed stop 3302 is also configured such that the vertical surface 3304 and the horizontal surface 3306 are positioned to prevent over-rotation of the rocker arm 3202.

For example, the illustrated rocker arm 3202 may include a rearward facing surface 3308, which in this case is defined by a control valve boss formed in the rocker arm 3202. In the event of an abrupt rearward rotation, the rearward facing surface 3308 will contact the vertical surface 3304 and prevent over-rotation of the rocker arm 3202. Similarly, the rocker arm further includes an upwardly facing surface 3310. In the event of an abrupt rearward rotation, the rearward facing surface 3310 will contact the horizontal surface 3306 and prevent over-rotation of the rocker arm 3202. Although the illustrated embodiment includes both a vertical surface 3304 and a horizontal surface 3306, this is not a requirement as it is contemplated that either such surface may be sufficient to prevent over-rotation depending on the configuration of the rocker arm 3202.

Fig. 34 and 35 show a valve bridge and a valve bridge guide according to an eleventh embodiment. In this embodiment, a valve bridge guide 3404 is provided that is attached to (or integrally formed with) a valve bridge body 3402. As shown, the valve bridge guide 3404 is disposed on one side of a valve bridge body 3402 that is not intended to engage an engine valve (not shown) that may also be actuated by an auxiliary motion source. In the illustrated embodiment, the valve bridge guide 3404 is shaped as a semi-cylindrical wall configured to be attached to the lower surface 3502 of the valve bridge body 3402 such that the semi-cylindrical wall extends downward from the lower surface 3502. However, it should be understood that the valve bridge guide 3404 may be attached at some other surface (e.g., an upper surface) of the valve bridge body 3402, so long as the semi-cylindrical wall extends downwardly below the lower surface 3502 as shown.

FIG. 36 shows the valve bridge and valve bridge guide of FIGS. 34 and 35 deployed in a valve actuation system. As shown, the valve bridge body 3402 spans two engine valve stems, and the valve bridge guide 3404 surrounds the outboard lateral portion of the valve spring retainer 3602. The radius of the semi-cylindrical wall (preferably centered at or near the longitudinal axis of the corresponding engine valve stem) is configured such that there is no contact between the semi-cylindrical wall and the valve spring retainer 3602 or the corresponding valve spring 3604 during normal (i.e., controlled) operation of the valve bridge. On the other hand, the radius of the semi-cylindrical wall is further configured such that during the uncontrolled state of the valve bridge body 3402, the semi-cylindrical wall will contact the valve spring retainer 3602, but avoid contact with the valve spring 3604. Similar to the embodiment described above with respect to fig. 25 and 29, an increased radius spring retainer may be employed to better ensure contact between the valve spring retainer 3602 and the spring retainer (and preferably not the valve spring 3604).

As mentioned above, the present disclosure describes various embodiments and variations of a valve bridge guide that may be used to resist (i.e., prevent, minimize, or accommodate) uncontrolled movement of a valve bridge. While various features have been described in connection with particular embodiments, those skilled in the art will appreciate that various ones of such features may be incorporated into other embodiments described herein.

The claims (modification according to treaty clause 19)

1. A valve bridge for use with an engine valve assembly of an internal combustion engine, the engine valve assembly including at least two engine valves, wherein the at least two engine valves are actuated by a primary rocker arm and a first engine valve of the at least two engine valves is actuated by an auxiliary rocker arm via a bridge pin, the valve bridge comprising:

a valve bridge body configured to extend between the at least two engine valves, the valve bridge body including a through-hole configured to align with the first engine valve and receive the bridge pin, the valve bridge body further including a receptacle configured to align with a second engine valve of the at least two engine valves and receive a stem of the second engine valve; and

an upper surface formed on the valve bridge body and having a height such that when the valve bridge is in an uncontrolled state relative to the at least two engine valves, the upper surface contacts a surface of the primary or auxiliary rocker arm to resist uncontrolled movement of the valve bridge.

2. The valve bridge of claim 1, wherein the valve bridge further comprises:

a bridge pin boss having the through-hole formed therein, the bridge pin boss terminating at the upper surface.

3. The valve bridge of claim 1, wherein the valve bridge further comprises:

a portion of the valve bridge body aligned with the primary rocker arm, the portion terminating at the upper surface.

4. A valve bridge for use with an engine valve assembly of an internal combustion engine, the engine valve assembly including at least two engine valves, wherein a first engine valve of the at least two engine valves is actuated by an auxiliary rocker arm via a bridge pin, the valve bridge comprising:

a valve bridge body configured to extend between the at least two engine valves, the valve bridge body including a through-hole configured to align with the first engine valve and receive the bridge pin, the valve bridge body further including a receptacle configured to align with a second engine valve of the at least two engine valves and receive a stem of the second engine valve,

wherein the through-hole is configured to provide clearance between the through-hole and the bridge pin such that when the valve bridge is in an uncontrolled state relative to the at least two engine valves, jamming between the bridge pin and the through-hole resists uncontrolled movement of the valve bridge.

5. A valve actuation assembly for actuating at least two engine valves in an internal combustion engine, the valve actuation assembly comprising:

a valve bridge having a valve bridge body configured to extend between the at least two engine valves, the valve bridge body including a portion extending downwardly from between the at least two engine valves; and

a spring retainer operatively connected to an engine valve of the at least two engine valves, wherein the spring retainer is configured to have an increased radius relative to a radius of a valve spring operatively connected to the spring retainer such that the downwardly extending portion of the valve bridge body contacts the spring retainer to resist uncontrolled movement of the valve bridge when the valve bridge is in an uncontrolled state relative to the at least two engine valves.

6. The valve actuation assembly of claim 5, wherein the downwardly extending portion further includes a hook feature extending away from the downwardly extending portion and toward the spring retainer, wherein the hook feature extends past an outer circumference of the spring retainer.

7. A valve actuation assembly for actuating at least two engine valves in an internal combustion engine, the valve actuation assembly comprising:

a valve bridge having a valve bridge body configured to extend between the at least two engine valves, the valve bridge body including a through-hole configured to align with a first engine valve of the at least two engine valves; and

a first bridge pin located on a first stem of the first of the at least two engine valves and configured to be received in the through bore, the first bridge pin further configured to slide on the first stem such that the valve bridge body remains aligned with the at least two engine valves during uncontrolled movement of the valve bridge when the valve bridge is in an uncontrolled state relative to the at least two engine valves.

8. The valve actuation assembly of claim 7, further comprising:

a second bridge pin located on a second stem of a second engine valve of the at least two engine valves and configured to be received in a second through hole formed in the valve bridge body and aligned with the second engine valve, the second bridge pin further configured to slide over the second stem such that the valve bridge body remains aligned with the at least two engine valves during the uncontrolled movement of the valve bridge.

9. A valve actuation assembly for actuating at least two engine valves in an internal combustion engine, the valve actuation assembly comprising:

a valve bridge having a valve bridge body configured to extend between the at least two engine valves and including receptacles configured to align with and respectively receive stems of the at least two engine valves, the valve bridge body further including a laterally extending slot that laterally intersects a respective one of the receptacles, wherein when the stems are received in the receptacles, the laterally extending receptacles align with annular channels formed in respective ones of the stems; and

a clip inserted into and engaging a respective one of the laterally extending slots and engaging a respective one of the annular channels such that the clip resists uncontrolled movement of the valve bridge when the valve bridge is in an uncontrolled state relative to the at least two engine valves.

10. A valve actuation assembly for actuating at least two engine valves in an internal combustion engine, the valve actuation assembly comprising:

a valve bridge having a valve bridge body configured to extend between the at least two engine valves, the valve bridge body including open laterally extending slots extending into the valve body, each of the slots defining an arm; and

bridge pins each including a body having end caps oppositely formed thereon, each of the end caps having an increased diameter relative to the body, each body having a receptacle formed therein configured to receive a respective stem of an engine valve of the at least two engine valves, the body of each of the bridge pins further configured to be received in a corresponding one of the slots while allowing vertical movement of the bridge pin therein, wherein the vertical movement of the bridge pin is limited by contact of the end cap with the arm of the corresponding slot.

11. The valve actuation assembly of claim 10, wherein a first engine valve of the at least two engine valves is actuated by an auxiliary rocker arm via a corresponding one of the bridge pins, the valve actuation assembly further including an upper surface formed on the valve bridge body and having a height such that when the valve bridge is in an uncontrolled state relative to the at least two engine valves, the upper surface contacts a surface of the auxiliary rocker arm to resist uncontrolled movement of the valve bridge.

12. A valve actuation assembly for actuating at least two engine valves in an internal combustion engine, the valve actuation assembly comprising:

a rocker arm operatively connected to the at least two engine valves, the rocker arm including an upwardly facing surface or a rearwardly facing surface or both;

a stop including a stop fixed relative to the rocker arm, the stop including a horizontal surface or a vertical surface, or both, the stop further configured such that the horizontal surface or the vertical surface, or both, are configured to avoid interference with the rocker arm during a controlled state of the rocker arm, but to allow contact between the upward facing surface and the horizontal surface or contact between the rearward facing surface and the vertical surface, or both, to resist over-rotation of the rocker arm when the rocker arm is in an uncontrolled state relative to the at least two engine valves.

13. The valve actuation assembly of claim 12, further including a rocker shaft on which the rocker arm is mounted for reciprocal movement, wherein the stop is fixed to the rocker shaft.

14. A valve bridge system for use with an engine valve assembly of an internal combustion engine, the engine valve assembly including at least two engine valves, at least two valve springs corresponding to the at least two engine valves, and at least two spring retainers corresponding to the at least two engine valves, the valve bridge system comprising:

a valve bridge configured to extend between the at least two engine valves, the valve bridge including a lower surface; and

a valve bridge guide operably connected to the valve bridge and including a semi-cylindrical wall configured to extend downwardly below the lower surface of the valve bridge and further configured to enclose an outboard lateral portion of a spring retainer of the at least two spring retainers,

wherein the semi-cylindrical wall is configured to not contact the spring retainer when the valve bridge is in a controlled state relative to the at least two engine valves,

and wherein the semi-cylindrical wall is configured to contact the spring retainer to resist uncontrolled movement of the valve bridge when the valve bridge is in an uncontrolled state relative to the at least two engine valves.

15. The valve bridge system of claim 14, wherein the valve bridge guide is operably connected to the lower surface of the valve bridge.

Claims

1. A valve bridge for use with an engine valve assembly of an internal combustion engine, the engine valve assembly including at least two engine valves, wherein a first engine valve of the at least two engine valves is actuated by an auxiliary rocker arm via a bridge pin, the valve bridge comprising:

a valve bridge body configured to extend between at least two engine valves, the valve bridge body including a through-hole configured to align with the first engine valve and receive the bridge pin, the valve bridge body further including a receptacle configured to align with a second engine valve of the at least two engine valves and receive a stem of the second engine valve; and

a bridge pin boss having the through-hole formed therein, the bridge pin boss having a longitudinal length and terminating in an upper surface, wherein the longitudinal length is configured such that the upper surface of the bridge pin boss contacts a surface of the auxiliary rocker arm to resist uncontrolled movement of the valve bridge when the valve bridge is in an uncontrolled condition relative to the at least two engine valves.