JP2023523753A - Valve bridge system to resist uncontrolled movement of the valve bridge - Google Patents

Abstract

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

Description

FIELD OF THE DISCLOSURE The present disclosure relates generally to valve actuation systems for internal combustion engines, and more particularly to valve bridge systems with valve bridge guides used in conjunction with such valve actuation systems.

Valve actuation systems for use with internal combustion engines are well known in the art. Such valve actuation systems typically include a valve train with one or more components that transmit valve actuation motion from a source of valve actuation motion (eg, one or more cams) to the engine valves. A common component in valve trains is the so-called valve bridge, which comprises a device that spans two or more engine valves associated with a given cylinder. In many cases, such valve bridges allow another component of the valve train (eg, a rocker arm) to simultaneously actuate two additional engine valves that engage the valve bridge. Ideally, during operation, the opposing forces exerted by the motion transmission components (such as the rocker arms) and the engine valve springs should be such that the motion transmission components and the engine valves at the same time as the valve bridges (allow normal lash setting). contact). In this manner, the valve bridge is positioned to consistently maintain alignment with the engine valve and transmit valve actuation motion to the engine valve. 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 provide so-called auxiliary valve actuation motion, i.e., valve actuation motion other than or in addition to the valve actuation motion used to operate the engine in a positive power production mode through combustion of fuel. configured to provide In such valve actuation systems, the valve bridge may include a device or lost motion assembly that allows valve actuation motion to be transmitted to the engine valves through the valve bridge, or such motion may be transmitted through the valve bridge. can be configured to be selectively "lost" if not transmitted to the engine valves via . FIG. 1 illustrates such a system as described in US Patent Application Publication No. 2012/0024260, the teachings of which are incorporated herein by this reference. In this case, valve bridge 710 includes a lost motion assembly in the form of a locking mechanism. In the illustrated embodiment, the locking mechanism comprises a ball 740 that can be pushed through an opening in the outer plunger 720 to engage a recess 770 formed in the body of the valve bridge. In this state, ball 740 is prevented from disengaging from recess 770 due to the outer diameter of inner plunger 760 , thereby locking outer plunger 720 in a fixed relationship to valve bridge 710 . As a result, any valve actuation motion imparted to outer plunger 720 by rocker arm 200/400 is transmitted to valve bridge 710 and 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 from the recess 770 in the valve bridge 710, thereby unlocking the outer plunger 720 and closing the valve bridge. 710 to allow reciprocating motion. In this condition, any valve actuation motion applied to the outer plunger 720 moves the outer plunger within the valve bridge 710 and is not transmitted to the engine valves. Another valve bridge-based locking/unlocking system is disclosed in US Patent Application Publication No. 2014/0326212, the teachings of which are incorporated herein by this reference.

However, in systems of the type illustrated in FIG. 1, the possibility of partial engagement of the locking mechanism exists. In this case, a valve actuation motion is first applied to the engine valve, thereby allowing the engine valve to lift off the valve seat. However, due to the partial engagement of the locking mechanism, an increase in load or vibration in the valve actuation system causes the locking mechanism to quickly switch from a partially locked state to an unlocked state. When this happens, the force provided by the valve actuation motion to open the engine valve is suddenly removed, and under the appreciable force of the valve spring, the engine valve can rapidly accelerate into its unrestrained closed position. It becomes possible. When the engine valve reaches its fully closed position (i.e. rests against the valve seat formed in the cylinder head), the momentum applied to the valve bridge causes it to hit a rocker arm or some other object. Until then, it can continue on an uncontrolled trajectory generally away from the engine valves. In fact, it is possible for the valve bridge to detach from either tip of the engine valve, resulting in the valve bridge falling off the engine valve, thereby causing 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. is called It is also known that an uncontrolled valve bridge condition occurs as a result of overspeed operation of an internal combustion engine.

Given this potential for malfunction, a solution to prevent, minimize or accommodate uncontrolled valve bridge conditions (regardless of cause) would represent a welcome addition to the art.

The present disclosure describes a valve bridge system that overcomes the above problems with prior art valve bridge systems. In a first primary embodiment, a valve bridge system comprises a valve bridge configured to extend between at least two engine valves of an internal combustion engine. The valve bridge guide is operatively connected to the valve bridge and comprises a valve bridge or engine valve assembly (at least two engine valves, at least two valve springs corresponding to the at least two engine valves, and at least two valve springs corresponding to the at least two engine valves). a valve bridge control surface for selectively contacting at least one of the at least two spring retainers. In this embodiment, the valve bridge guide may be out 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 with respect to the at least two engine valves; It is configured to contact the valve bridge or engine valve assembly to resist uncontrolled movement of the valve bridge when in an uncontrolled condition relative to the engine valve. In one embodiment, the valve bridge guide is configured to extend between at least two valve springs and the valve bridge control surface is at least one valve defined by the at least two valve springs or the at least two spring retainers. At least one concave surface corresponding to the convex surface or convex surface defined by a portion of the valve bridge. More specifically, each of the at least one concave surface is configured such that a line intersecting both edges forms a secant line to the outer diameter of the corresponding one of the at least two valve springs or the at least two spring retainers. , may be defined by both edges.

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

In a second primary embodiment, the valve bridge system may comprise a valve bridge configured to extend between at least two engine valves of an internal combustion engine, the valve bridge facing the at least two engine valves. and a top surface opposite the bottom surface. The system of this main embodiment further comprises a valve bridge guide having a first member maintained in a first fixed position relative to the valve bridge, the first member being positioned to hold the at least two engine valves closed. It comprises a first surface facing the top surface of the valve bridge and at a predetermined distance from the top surface of the valve bridge when in the state. The predetermined distance prevents contact between the first surface and the upper surface of the valve bridge when the upper bridge body is in a controlled condition with respect to the at least two engine valves, the valve bridge being positioned between the at least two engine valves. It is configured to allow contact between the first surface and an upper surface of the valve bridge to resist uncontrolled movement of the valve bridge when in an uncontrolled condition relative to the engine valve. If the valve bridge comprises a receptacle for receiving an engine valve tip of one of the at least two engine valves, the predetermined distance may be less than the 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, the first engine valve furthest from a rocker shaft of the internal combustion engine. The valve bridge system may further comprise a second member maintained in a second fixed position relative to the valve bridge, the second member facing the upper surface of the valve bridge and extending from the upper surface of the valve bridge to a predetermined position. A second surface is provided at a 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, the second engine valve being closest to the rocker shaft of the internal combustion engine. The first member may be configured to be attached to the cylinder head of the internal combustion engine, while the second member may form an integral structure with the rocker shaft pedestal of the internal combustion engine.

In a further alternative to this second main embodiment, the valve bridge guide may further comprise a bridge pin disposed at one end of the valve bridge and in alignment with the 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 to be attached to the cylinder head and extending between at least two engine valves and over the upper surface of the valve bridge; The arch also includes an opening formed therein that aligns with the portion of the valve bridge that contacts the valve train component.

The features set forth in the 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 in conjunction with the accompanying drawings. By way of example only, one or more embodiments will now be described with reference to the accompanying drawings, where like reference numerals represent like elements.
1 is a cross-sectional illustrative view of a valve actuation system including a valve bridge having a locking mechanism according to the prior art; FIG. 1A and 1B are top and bottom isometric cross-sectional views, respectively, of a first main embodiment of a valve actuation system comprising a valve bridge and a valve bridge guide according to the present disclosure; 1A and 1B are top and bottom isometric cross-sectional views, respectively, of a first main embodiment of a valve actuation system comprising a valve bridge and a valve bridge guide according to the present disclosure; FIG. 4 is a schematic diagram illustrating the relationship between the valve spring and the surface of the valve bridge guide according to the first main embodiment; 1A-1D are respectively an isometric view and a cross-sectional view (along section line VI-VI) of a valve bridge and a valve bridge guide according to a first variant of the first main embodiment; 1A-1D are respectively an isometric view and a cross-sectional view (along section line VI-VI) of a valve bridge and a valve bridge guide according to a first variant of the first main embodiment; Figures 8A and 8B are respectively an isometric view and a sectional view (along section line VIII-VIII) of a valve bridge and a valve bridge guide according to a second variant of the first main embodiment; Figures 8A and 8B are respectively an isometric view and a sectional view (along section line VIII-VIII) of a valve bridge and a valve bridge guide according to a second variant of the first main embodiment; Figures 7A and 7B are isometric and cross-sectional views (along section line XX), respectively, of a valve bridge and a valve bridge guide according to a third variant of the first main embodiment; Figures 7A and 7B are isometric and cross-sectional views (along section line XX), respectively, of a valve bridge and a valve bridge guide according to a third variant of the first main embodiment; FIG. 11 is an isometric view of a valve bridge guide according to a fourth variant of the first main embodiment; FIG. 11 is an isometric view of a valve bridge and a valve bridge guide according to a fifth variant of the first main embodiment; FIG. 11 is an isometric view of a valve bridge guide according to a sixth variant of the first main embodiment; Figures 7A and 7B are isometric and cross-sectional views, respectively, of a valve bridge guide according to a seventh variant of the first main embodiment; Figures 7A and 7B are isometric and cross-sectional views, respectively, of a valve bridge guide according to a seventh variant of the first main embodiment; FIG. 11 is an isometric view of a valve bridge guide according to an eighth variant of the first main embodiment; FIG. 11 is an isometric view of a valve bridge guide according to a ninth variant of the first main embodiment; Figures 4A and 4B are isometric, side and front views, respectively, of a valve bridge and a valve bridge guide according to the second main embodiment; Figures 4A and 4B are isometric, side and front views, respectively, of a valve bridge and a valve bridge guide according to the second main embodiment; Figures 4A and 4B are isometric, side and front views, respectively, of a valve bridge and a valve bridge guide according to the second main embodiment; Figures 4A and 4B are isometric, side and front views, respectively, of a valve bridge and a valve bridge guide according to the second main embodiment; Fig. 10 is a top isometric view of a valve bridge and valve bridge guide according to a first variant of the second main embodiment; 1 is a cross-sectional view of a valve bridge according to prior art techniques; FIG. FIG. 11 is a cross-sectional view of a valve bridge according to the third main embodiment; FIG. 10 is a cross-sectional view of a valve bridge according to fourth to sixth main embodiments; Figures 7A and 7B are top, isometric and cross-sectional views, respectively, of a valve bridge according to the seventh main embodiment; Figures 7A and 7B are top, isometric and cross-sectional views, respectively, of a valve bridge according to the seventh main embodiment; Figures 7A and 7B are top, isometric and cross-sectional views, respectively, of a valve bridge according to the seventh main embodiment; FIG. 12 is a side view of the valve bridge according to the eighth main embodiment; Figures 13A and 13B are isometric and cross-sectional views, respectively, of a valve bridge and a bridge pin according to the ninth main embodiment; Figures 13A and 13B are isometric and cross-sectional views, respectively, of a valve bridge and a bridge pin according to the ninth main embodiment; 1 is a side, partially cross-sectional view of a valve actuation system according to prior art techniques; FIG. FIG. 11 is a top isometric view of a valve actuation system according to a tenth embodiment; Figures 13A and 13B are top and bottom isometric views, respectively, of a valve bridge and a valve bridge guide according to an eleventh embodiment; Figures 13A and 13B are top and bottom isometric views, respectively, of a valve bridge and a valve bridge guide according to an eleventh embodiment; Figure 36 is a top isometric view of the valve bridge and valve bridge guide of Figures 34 and 35 deployed in a valve actuation system;

2-36 illustrate various embodiments of valve bridge systems with valve bridge guides according to the present disclosure. In all of the embodiments and variations illustrated in FIGS. 2-36, the valve bridge is of the type illustrated in FIG. 1, i.e. the general valve bridge illustrated in FIG. Assume a valve bridge with a locking mechanism of the type

FIG. 2 illustrates a first embodiment according to the present disclosure in which an internal combustion engine 202 includes a pair of valve bridges 204, 212 for a single cylinder. In the illustrated embodiment, each valve bridge 204, 212 operates two corresponding engine valves, although it is possible for each valve bridge to operate more than two engine valves. As is known in the art, each valve bridge 204, 212 (or any of the other valve bridges illustrated and described herein) includes two engine valves of the same type, namely two One intake valve or two exhaust valves can be operated. For ease of illustration, the features and operations of only the first valve actuation system according to the first embodiment are described, but the features and operations described apply equally to all valve bridges included in an internal combustion engine. It is understood that it is possible.

Thus, as shown, a first valve bridge 204 spans a pair of engine valves (not visible in FIG. 2) in a conventional manner known in the art. Each engine valve has a valve spring 208, 210 that biases its corresponding engine valve to a closed condition (i.e., a condition in which the engine valve head engages a valve seat formed in the cylinder head 230), and the engine valve and valve spring retainers 209, 211 attached to the valve stems. As further shown, valve bridge system 202 includes valve bridges that extend downward (i.e., toward the cylinder head and away from rocker arm 220) from valve bridge 204 and between valve springs 208, 210. A guide 206 is further provided. In one embodiment, the distance that valve bridge guide 206 extends between valve springs 208, 219 is the portion of valve bridge 204 that surrounds the locking mechanism (eg, referring to FIG. 1, outer plunger 720 and outer plunger spring). 746). In the embodiment illustrated in FIG. 2, the valve bridge and valve bridge guide form a unitary structure, i.e., an undivided integral part, whereby the locking mechanism comprises valve bridge 204 and valve bridge guide 206. is received within an opening (best shown in FIG. 3) formed in the . As will be described in more detail below, the valve bridge guide 206 may be used to prevent, minimize, or at least accommodate uncontrolled movement of the valve bridge 204 by adjusting the position of the valve springs 208 , 210 or valve spring retainers 209 , 211 . at least one valve bridge control surface configured to interact with one or both of them.

FIG. 3 illustrates a cross-sectional view of valve spring guide 206 and first valve spring 208 taken along section line III-III (as shown in FIG. 2). An opening 310 is formed in the valve spring guide 206 to accommodate the locking mechanism and FIG. 3 further illustrates a valve stem 320 disposed within the corresponding valve spring 208 . More specifically, FIG. 3 illustrates that the valve bridge control surfaces 402 are matched to corresponding valve springs 306 (only one is shown in FIG. 3), i.e., the valve bridge control surfaces 402 The two valve bridge control surfaces 402 defined by the valve bridge guide 206 are illustrated to be concave with respect to the convex outer surfaces of 208,210. Although compatible, the valve bridge control surfaces 402 prevent the valve bridge control surfaces 402 (and thus the valve bridge guides 206) from contacting their corresponding valve springs 208, 210 during the valve bridge controlled state. designed to be avoidable. The valve bridge control surface 402 is closed until normal movement and vibration of the valve bridge 204, valve bridge guides 206, and valve springs 208, 210 cause contact between the valve bridge control surface 402 and the valve springs 208, 210. It may be configured to be as close as possible (within manufacturing tolerances) to the valve springs 208, 210 so as to be insufficient. For example, as is known in the art, when compression springs, such as valve springs 208, 210, are deformed (ie compressed), the outer diameter of the spring increases slightly. Accordingly, the valve bridge control surface 402 may be configured to allow for the maximum expected change 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, otherwise it may lead to premature deterioration of the valve springs 208,210. Therefore, it may be desirable to configure the valve bridge control surface 402 to contact the spring retainers 209, 211 instead. In order to achieve this configuration, it may be necessary to dimension the spring retainers 209,211 to have an outer diameter that is larger than the outer diameter of the valve springs 28,210. In this case, the valve bridge control surface 402 is instead configured such that the valve bridge control surface 402 conforms to the corresponding spring retainer 209,211, i.e., the valve bridge control surface 402 conforms to the convex outer surface of the spring retainer 209,211. defined by valve bridge guide 206 so as to be concave with respect to . Again, such concave surfaces are configured to allow the valve bridge control surfaces 402 to avoid contact with their corresponding spring retainers 209, 211 during valve bridge controlled conditions. Furthermore, normal movement and vibration of valve bridge 204, valve bridge guides 206 and valve springs 208, 210 are insufficient to cause contact between valve bridge control surface 402 and spring retainers 209, 211. As such, it is configured to be as close as possible (within manufacturing tolerances) to the valve springs 208,210.

Although the various figures illustrated and described in this disclosure show at least two concave valve bridge control surfaces 402, this is not a requirement. For example, a single such valve bridge control surface 402 may be employed when used in conjunction with another feature that provides additional control of otherwise uncontrolled movement of valve bridge 204 . For example, if the valve bridge 204 comprises bridge pins (see, eg, element 2102 in 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 the preferred embodiment is further described in connection with FIG. 4, which schematically illustrates the valve bridge guides 206 and valve springs 208 in enlarged form. (Alternatively, as discussed above, the valve spring 208 illustrated in FIG. 4 may be a spring retainer, although only the valve spring 208 is described herein for ease of explanation.) .) As shown, the valve bridge guide 206 includes a concave valve bridge control surface 402 proximate the outer diameter 408 of the valve spring 208 . In practice, the clearance between valve bridge control surface 402 and outer diameter 408 is based in part on manufacturing tolerances of valve springs 208 , 210 (or spring retainers 209 , 211 ) and valve bridge 204 . Further, this clearance is based on the clearance of the engine valve tips within the receptacles formed in the valve bridge 204 to receive the engine valve tips. For example, if the valve bridge 204 is allowed to move ±0.25 mm, the clearance between the valve springs 208 and the valve bridge control surface 402 will add the 0.25 mm play allowed for part tolerances. must be larger than the Further, the chamfer on the bottom of the valve bridge 204 allows the valve bridge 204 to position itself over the tip of the engine valve even if the valve bridge 204 experiences uncontrolled movement over the full clearance to the valve spring or spring retainer. Must be large enough to allow rearrangement.

As further shown in FIG. 4, the circumferential length of concave valve bridge control surface 402 (relative to outer diameter 408 of spring 208) is defined by opposite edges 404,406. In this preferred embodiment, the edges 404, 406 are such that when the valve bridge guide 206 is positioned during the controlled state of the valve bridge 204, a line 410 intersecting the edges 404, 406 as shown is at least the valve position. They are spaced apart to form a secant line to the outer diameter 408 of the spring 208 . So configured, movement of the valve bridge guide 206 in either direction indicated by line 410 (such as may occur during an uncontrolled state of the valve bridge 204) should be sufficiently large. , contact the concave valve bridge control surface 402 with the spring outer diameter 408 , thereby generally biasing the valve bridge guide 206 away from the valve spring 208 toward the other valve spring 210 . . More generally, any rotational movement of valve bridge 204 about the centerline axis of the locking mechanism is constrained as well as lateral movement in both horizontal planes. With this in mind, and returning to FIGS. 2 and 3, this movement of the concave valve bridge control surface 402 during the uncontrolled state of the valve bridge 204 causes the valve bridge guide 206 itself to act as a valve spring. 208 , 210 , thereby effectively damping or even eliminating uncontrolled movement of valve bridge 204 and valve bridge guide 206 .

5 and 6, a first variation of the valve bridge guide 502 is a separate unit from the valve bridge 204, as shown, having a valve bridge control surface 402 formed on a side thereof. Prepare oneness. Valve bridge 204 is also illustrated as having a receptacle 614 for receiving the tip of a valve stem of an engine valve, as known in the art and described above. In this embodiment (as well as further embodiments illustrated in FIGS. 7-13), valve bridge guide 502 may be manufactured from the same material as valve bridge 204 (eg, steel), but in a preferred embodiment: The valve bridge guide 502 is made of a softer, yet lighter and stronger material than the valve bridge springs 208, 201 (or spring retainers 209, 211) to avoid scratching or damage. For example, suitable moldable polymers as known in the art can be used for this purpose. Still further types of materials for manufacturing valve bridge guides 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 configured to closely receive portion 604 of valve bridge 204 . As shown, the portion 604 of valve bridge 204 received by valve bridge guide 502 preferably houses at least a portion of locking mechanism 606 . As further shown, in this embodiment both valve bridge guide 502 and portion 604 of valve bridge 204 include fastener receiving features 504 , 608 . In this embodiment, the valve bridge guide fastener receiving feature 504 comprises a bore that intersects with an opening 602 formed in the valve bridge guide 502 . Thus, where the bore intersects opening 602 , fastener receiving feature 504 essentially comprises a channel having a semi-circular cross-section formed in the sidewall of opening 602 . In a complementary manner, fastener receiving features 608 of portion 604 of valve bridge 204 are also formed as semi-circular channels in the outer wall 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 fasteners 612 may comprise split dowel pins, as shown, although those skilled in the art will recognize that other types of fasteners, such as screws, may equally be employed. would do. In this manner, valve bridge guides 502 are relatively rigidly attached to valve bridge 204 so 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 illustrated in FIGS. 7-13) may instead be suitably strong and durable. It may be fixedly attached to the valve bridge 204 using some epoxy or similar adhesive. Additionally, combinations of such techniques may also be employed as design options.

7 and 8, a second variation of valve bridge guide 702 is a separate unitary guide from valve bridge 204, as shown, having valve bridge control surfaces 402 formed on its sides. It is substantially similar to valve bridge guide 502 of FIGS. 5 and 6 in that it is integral. However, in this embodiment, valve bridge guide 702 extends inwardly from the sidewall of opening 602 and is configured to engage notch 804 formed in the outer sidewall of portion 604 of valve bridge 204 . and one or more teeth 802 . For example, notch 804 may comprise an annular groove or channel formed in sidewalls of portion 604 of valve bridge 204 . When tooth 802 engages notch 804, valve bridge guide 702 is operatively connected to valve bridge, again in a relatively rigid manner, such that valve bridge guide 702 and valve bridge 204 move in unison. . It should be noted that in this embodiment, the arrangement of the one or more teeth 802 and the notch 804 can equally be reversed, i.e. the teeth 802 can be formed on the outer side wall surface of the portion 604 of the valve bridge 204, Note that notch 804 may be formed in the inner side wall of opening 602 .

As further shown in FIG. 7, valve bridge guide 702 may comprise at least two projecting members 704 , 706 projecting from valve bridge guide 702 towards valve bridge 204 . As shown in FIG. 8, valve bridge 204 has a lower surface 806 and, in one embodiment, projecting members 704 , 706 extend beyond at least lower surface 806 of valve bridge 204 . In this embodiment, at least two projecting members 704 , 706 help orient valve bridge guide 702 over valve bridge 204 , thereby preventing rotation of valve bridge 204 relative to valve bridge guide 702 . In this manner, the at least two projecting members 704,706 further assist in aligning the valve bridge control surface 402 with the valve springs 208,210 or spring retainers 209,211.

9 and 10, a third variation of the valve bridge guide 902 is illustrated, as shown, the valve bridge guide 902 again having valves formed on its sides. It is formed as a single piece separate from the valve bridge 204 with the bridge control surface 402 . However, in this embodiment the valve bridge guide 902 has a side opening 904 with a cantilevered latch or catch 906 disposed therein. As shown, catches 906 are configured to engage corresponding notches 1002 formed in the outer sidewall surface of portion 604 of valve bridge 204 . For example, notch 1002 may again comprise an annular groove or channel formed in the sidewall of portion 604 of valve bridge 204 . When catch 906 engages notch 804, valve bridge guide 702 is operably connected to valve bridge, again in a relatively rigid manner, such that valve bridge guide 902 and valve bridge 204 move in unison. . As shown, valve bridge guide 902 may further include secondary latch surfaces 908 configured to engage corresponding secondary notches 1004 formed in portion 604 of valve bridge 204 . By providing multiple latch pairs 906, 1002/908, 1004, the stability of valve bridge guide 902 relative to valve bridge 204 may be improved.

Referring now to FIG. 11, a fourth variation of valve bridge guide 1102 is shown. In this variation, valve bridge guide 1102 is a single piece disposed between spring retainers 209 , 211 and valve bridge 204 . Notches 1104, 1106 are provided to allow the valve bridge guide 1102 to position against the tip of the engine valve. Additionally, a central opening 1107 may be provided that allows a portion of valve bridge 204 (eg, the portion housing the locking mechanism as shown in FIG. 1) to extend through valve guide 1102 . 7 and 8, the valve bridge guide 1102 comprises at least two protruding members in the form of sidewalls 1108, 1110 that define a channel 1116 to receive the valve bridge 204. It is configured. In this embodiment, the inner surfaces 1112, 1114 of the sidewalls 1108, 1110 that rise above the valve bridge 204 prevent lateral movement or rotation of the valve bridge 204 that may occur during uncontrolled conditions of the valve bridge 204. Acts as a valve bridge control surface. Additionally, although not shown in FIG. 11, an additional valve bridge control surface 402 is optionally located on the lower portion 1118 of the valve bridge guide 1102 to prevent tilting of the valve bridge 204, as described above. can be provided in a timely manner. As long as the valve bridge guide 1102 is fixedly attached to the valve bridge 204 (using any of the techniques described above), excessive lift of the valve bridge 204 (e.g., off the tip of the engine valve) ) will cause a similar lift within the valve bridge guide 1102, which again resists uncontrolled movement and allows the valve bridge 204 to rest back on the engine valve tips.

Referring now to FIG. 12, a fifth variation of valve bridge guide 1202 comprises a unitary body separate from valve bridge 204 having valve bridge control surfaces 402 formed on its sides as shown. 5 and 6 is substantially similar to the valve bridge guide 502 of FIGS. As further shown, and similar to the second variation illustrated in FIGS. There are further protruding members 1204-1212, which serve similar purposes as described above. Further, as shown, each of the projecting members 1204-1212 has mounting surfaces 1214, 1216 (see FIG. 12) in the form of inwardly extending fingers 1214, 1216 disposed at distal ends of the projecting members 1204-1212. are shown). The mounting 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, similar to the embodiment of FIGS. 9 and 10, fingers 1214, 1216 may instead engage notches or similar features formed in the sides of valve bridge 204. FIG.

Figure 13 illustrates a sixth variation of the first embodiment in which the valve bridge guide 1302 is formed from two guide members 1304, 1306 configured to engage opposite sides of the valve bridge. ing. As with other embodiments, each of the guide members 1304, 1306 defines a valve bridge control surface 402 as described above. Additionally, each of the guide members 1304, 1306 defines a first opening 1308 (only one shown) configured to receive a portion 604 of the valve bridge 204 (not shown). As further shown, each of the guide members 1304, 1306 also supports one of the arms of the valve bridge 204 (i.e., that portion of the valve bridge that extends from the center of the valve bridge to one of the engine valves). ) is also included in the channel or second opening 1310 configured to receive the . Further, each of the guide members 1304, 1306 has complementary first latch 1312 and first latch notch 1314 and second latch 1316 and second latch such that the guide members 1304, 1306 can be fixedly connected to each other. fasteners in the form of latch notches 1318. Alternatively, any of the attachment mechanisms described above (dowel pins, epoxy, etc.) can be used as "fasteners" for this purpose. When connected, the guide members 1304, 1306 bring together the valve bridge guide 1302 which is maintained in position relative to the valve bridge 204 by the fact that the second opening 1310 encompasses the arms of the valve bridge 204. define.

Figures 14 and 15 show a seventh variation of the first main embodiment in which the valve bridge guide 1402 is formed as a stamped sheet metal structure having a horizontal surface 1404 and continuous sidewalls 1406 extending downwardly therefrom. Illustrate. In this variation, similar to the embodiment illustrated in FIG. 11, valve bridge guides 1402 are mounted above spring retainers 209, 211 (FIG. 15) and below valve bridge 204 (not shown). is designed to In FIG. 15, sidewall 1406 is shown extending beyond the initial portion of spring retainers 209, 211 and valve springs 208, 210. FIG. In one embodiment, the extent of sidewall 1406 is such that even if vertical displacement is applied to valve bridge 204, valve bridge guide 1402 is completely disengaged from spring retainers 209, 211 and cannot be lifted. In addition to a central opening 1406 that allows passage of a portion of valve bridge 204, valve bridge guide 1402 also includes a plurality of protruding members similar to those illustrated in FIGS. 1408-1416 (four are shown in the illustrated example). As shown, the protruding members 1408-1416 are formed as upwardly curved portions of the horizontal surface 1404, resulting in openings 1426, 1428 that allow the tips of the engine valves 1502 to pass therethrough. In this case, projecting members 1408 - 1416 again define valve bridge control surfaces 1422 , 1424 to resist uncontrolled movement of valve bridge 204 .

FIG. 16 illustrates a first valve bridge guide 1602 comprising two guide members 1603 (only one shown) configured to engage opposite sides of valve bridge 204 (not shown). FIG. 12 illustrates an isometric view of an eighth variant of the main embodiment; FIG. Each guide member 1603 is formed as a stamped sheet metal structure having a horizontal surface 1604 and continuous sidewalls 1606 extending downwardly therefrom similar to the embodiment of FIGS. 14 and 15, but with only a single spring retainer 209. is configured to rest on the Again, each guide member 1603 comprises a plurality of upwardly extending projecting members 1608, 1610 and a central opening 1612 for the passage of engine valve tips, each projecting member 1608, 1610 A valve bridge control surface 1614 is defined for resisting uncontrolled movement of the bridge 204 .

Similar to the embodiment of FIG. 16, the embodiment illustrated in FIG. 17 is a valve bridge guide with a pair of guide members 1703 configured to rest on separate spring retainers 209,211. 1702. In this case, formed from a moldable polymer, each guide member 1703 comprises a horizontal surface 1704 and a continuous sidewall 1706 extending downwardly therefrom similar to the embodiment of FIGS. The configuration is configured to rest on only a single spring retainer 209 . Again, each guide member 1603 comprises a plurality of upwardly extending projecting members 1708, 1710 and a central opening 1712 for the passage of engine valve tips, each projecting member 1708, 1710 A valve bridge control surface 1614 is defined for resisting uncontrolled movement of the bridge 204 . However, in this case each guide member 1703 is also provided with a lateral concave valve bridge control surface 402, as explained above. However, in this case, the laterally concave valve bridge control surface 402 is not configured to conform to the outer surfaces of the valve springs 208, 210, but as described and illustrated above in connection with FIG. Additionally, it is configured to fit that portion of the valve bridge 204 that extends downward between the valve springs 208, 210 and houses the locking mechanism.

18-21, a second primary embodiment according to the present disclosure is illustrated, an internal combustion engine 202 comprising a pair of valve bridges 204, 212 for a single cylinder. In the illustrated embodiment, each valve bridge 204, 212 operates two corresponding engine valves, although again it is possible for each valve bridge to operate more than two engine valves. In the illustrated embodiment, the first valve bridge 204 spans a pair of engine valves in a conventional manner known in the art. Each engine valve has a valve spring 208, 210 that biases the corresponding engine valve closed and a valve spring retainer 209, 211 attached to the valve stem of the engine valve. As best shown in FIG. 19, the valve bridge 204 has a lower surface 1902 facing the engine valves and an upper surface 1904 opposite the lower surface 1902 .

As further shown in this second primary embodiment, the valve bridge system further comprises 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 maintained in a first fixed position relative to valve bridge 204 using suitable fasteners 1806 (such as bolts threaded into a cylinder head or similar fixed structure). In particular, the first fixed position maintains the first member a predetermined distance 1908 away from the top surface of valve bridge 204 when the at least two valve bridges are maintained in a closed state. Further, 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, the first engine valve being aligned with the rocker shaft of the internal combustion engine 202 . Farthest from 1808. As shown, the first member 1802 may be configured to align with the first engine valve for two or more valve bridges 204, 212 as described. Additionally, the first member 1802 may also extend across the valve bridges of multiple cylinders of an internal combustion engine in this matter, or the configuration of the cylinders may preclude the use of a single first member 1802. Cases may include a plurality of such first members 1802 .

In this embodiment, the predetermined distance 1908 between the first member 1802 and the top 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 top surface 1904 of the valve bridge 204, leaving the valve bridge 204 uncontrolled for at least two engine valves. At some point, it is sufficient to allow contact between first surface 1906 and upper surface 1904 to resist uncontrolled movement of valve bridge 204 . As used herein, uncontrolled movement of the valve bridge 204 means that any of the disclosed valve bridge guides, when operating in a controlled manner, moves the valve outside its normal range of motion. It is resisted to the extent that it opposes the movement of the bridge. Thus, the variations of the first embodiment illustrated in FIGS. 2-12 counter movement that could result in tilting or rotation of the valve bridge 204 with respect to the engine valve, but the first member 1802 counteracts excessive vertical displacement of the valve bridge 204 with respect to the engine valves, and in particular prevents the valve bridge 204 from completely disengaging from the engine valves. 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 nonetheless, the desired resistance to uncontrolled movement of valve bridge 204 may be provided. In one embodiment, the predetermined distance 1908 may be based on the depth 2002 of the receptacles 2004 provided by the valve bridges 204, 212 to engage the valve tips 2006 of the engine valves (Fig. 20). In particular, predetermined distance 1908 may be selected to be less than depth 2002 of receptacle 2004 . In this manner, the valve bridges 204, 212, if operated in an uncontrolled manner, may not move the first member before the valve bridges 204, 212 can travel a distance beyond the depth 2002 of the receptacle 2004. 1802 and otherwise disengage the valve bridges 204 , 212 from the valve tip 2006 . Additionally, some forms of engine braking are known to actuate only a single on-board engine valve (i.e., closest to the rocker shaft), thereby allowing that portion of the valve bridge to be external to the engine valves. (ie furthest from the rocker shaft) and raised slightly upward, eg, about 1-2 mm. Predetermined distance 1908 should therefore be selected to accommodate this possibility in order to avoid unwanted contact with valve bridge 204 . In addition, normal wear of engine valve seats can cause engine valve tips to lift over time, and predetermined distance 1908 should also take into account this possibility.

In this second embodiment, the valve bridge guide comprises a second member 1804 maintained in a second fixed position relative to valve bridge 204 and having a second surface 1910 facing upper surface 1904 of valve bridge 204 . be more prepared. As with first member 1802, second surface 1910 is maintained a predetermined distance 1908 from top surface 1904 for the same reasons explained above. In one embodiment, the second fixed position of the second member 1804 is aligned with a second engine valve of the at least two engine valves, the second engine valve being closest to the rocker shaft 1808. . Further, as best shown in FIGS. 18 and 19, second member 1804 may be formed as a unitary construction with rocker pedestal 1810 . In this manner, the first and second members 1802, 1808 may be aligned separately with different engine valves and at the same predetermined distance 1908 from the upper surface 1904, thereby providing uniform resistance to uncontrolled movement. Acts as a valve bridge guide providing good resistance.

As is known in the art, some valve actuation systems include auxiliary motion sources and valve trains that provide auxiliary motion to a single engine valve despite the presence of valve bridge 212 . This applies the auxiliary valve actuation motion to a single engine valve and the main valve actuation motion to a single engine valve through the valve bridge 212 as is known in the art. This is achieved through the use of bridge pins 2102 to enable. In this case, the presence of the bridge pin 712 passing through the valve bridge 212 effectively acts as a second member defining the valve bridge guide. That is, the presence of the bridge pin 712 (operably connected to both the auxiliary rocker arm 2104 and the single engine valve) causes the valve bridge 212 to operate in an uncontrolled manner. It operates to constrain only sliding movement relative to pin 712 . In this case, the presence of the secondary rocker arm 2104 (or other secondary valve train component) acts to prevent movement of the valve bridge 212 off the bridge pin 2102 . Again, when first member 1802 is provided (as shown), the joint action of the first and second members resists uncontrolled movement, particularly upward movement, of valve bridge 212. do.

Figure 22 illustrates a first variant of the second embodiment in which the valve bridge guide comprises a first member 2202 formed as a three-sided "strap". Similar to the embodiment of FIGS. 18-21, the variation illustrated in FIG. 22 resists uncontrolled movement by positioning the first member 2202 in a position that contacts the upper surface 1904 of the valve bridge. act to resist. In this embodiment, the first member 2202 comprises two substantially springs 208 , 210 extending from the top of the valve bridge 214 to the base of the engine valve springs 208 , 210 with each of the elongated sides 2204 attached to the cylinder head 230 . It may comprise sheet metal or similar material having vertical elongated sides 2204 (one shown in FIG. 22). A third substantially horizontal side 2206 of first member 2202 above the highest normal rest point of valve bridge 214 (i.e., when the engine valves are fully closed) and top surface 1904 of valve bridge 214 . connect with the first and second elongated sides 2204 . As with the embodiment of FIGS. 18-21, third side 2206 is preferably maintained in a fixed position a predetermined distance 1908 (not shown in FIG. 22) from top surface 1904 . As further shown, third side 2206 allows a portion of valve bridge 214 (eg, outer plunger 720/cap 730, referring to FIG. 1) to contact rocker arm 2212, as shown. It includes an opening 2210 for opening. Thus, in this variation, displacement of valve bridge 204 is constrained 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 shortcomings of prior art systems. In particular, FIG. 23 illustrates a valve bridge having a valve bridge body 2302 spanning two engine valve stems 2304,2306. As shown, first engine valve 2306 is actuated by auxiliary rocker arm 2312 via bridge pin 2308 which receives the stem of first engine valve 2306 . Bridge pin 2308 is then received within a through bore 2310 formed in valve bridge body 2302 and aligned with first engine valve 2306 , whereby bridge pin 2308 contacts auxiliary rocker arm 2312 . becomes possible. Additionally, valve bridge body 2302 includes a receptacle 2314 configured to align with and receive the stem of second engine valve 2304 . In FIG. 23, valve bridge 2302 is in an uncontrolled state as depicted by receptacle 2314 losing contact with second engine valve 2304 . This results from the fact that there is no surface provided to restrain upward movement of the valve bridge 2302 during uncontrolled conditions.

FIG. 24 illustrates a valve bridge according to the third main embodiment, showing a valve bridge substantially similar to that depicted in FIG. However, in this case the valve bridge also has a through bore 2404 formed therein and has a greater longitudinal length (or height) compared to the embodiment illustrated in FIG. Includes bridge pin bosses 2402 . As a result, the top surface 2406 of the bridge pin boss 2402 is closer to the bottom surface 2408 of the secondary rocker arm 2312 (eg, the bottom surface of the actuator in the depicted embodiment). Thus, when the valve bridge is in an uncontrolled state resulting in upward movement of the valve bridge body 2302, before the valve bridge body 2302 has the potential to fully disengage from the valve stem, the bridge pin boss 2402 is pushed into position. Upper surface 2406 contacts lower surface 2408 of secondary rocker arm 2312 . This is illustrated in FIG. 24, where contact between upper surface 2406 and lower surface 2408 prevents complete disengagement of receptacle 2410 from the stem of second engine valve 2304 .

It is also understood that a similar upper surface of that portion of valve bridge body 2302 aligned with primary rocker arm 2412 may also be configured in a similar manner as upper surface 2406 of bridge pin boss 2402 . In this case, the height of the valve bridge body 2302 aligned with the primary rocker arm 2412 is such that the top surface 2411 of the valve bridge body 2302 is aligned with the primary rocker arm 2412 (e.g., depicted) during uncontrolled movement of the valve bridge body 2302 . In some embodiments, it can be similarly increased to increase the likelihood of contact with the lower surface of the pivot foot. In this case, however, the height of top surface 2411 must be chosen so as not to interfere with the ability of folding mechanism 2412 to fully absorb any valve actuation motion provided by primary rocker arm 2412 . In other words, the top surface 2411 is up to the point of contact with the primary rocker arm 2412 during the controlled state (or controlled movement) of the valve bridge body 2302 and when the folding mechanism 2414 is absorbing the primary valve event. should not be increased.

Referring now to FIG. 25, valve bridges according to the fourth through sixth main embodiments are illustrated. In particular, FIG. 25 again illustrates a valve bridge similar in construction to the valve bridge illustrated in FIG. A fourth primary embodiment relates to the clearance feature between the inner diameter of throughbore 2502 and the outer diameter of bridge pin 2504 . In particular, by tightly controlling and minimizing the clearance between the throughbore and the bridge pin, the occurrence of uncontrolled motion can result in a "pinch" (or obstruction) of the valve bridge body 2302 and bridge pin 2504. be. This is illustrated in FIG. 25 by contact points 2505 between through bores 2502 and bridge pins 2504 . This pinch in turn tends to dampen any further movement of the valve bridge body 2302, thereby keeping the valve bridge body 2302 aligned with the engine valves.

FIG. 25 illustrates a fifth major embodiment of a spring retainer 2506 of increased radius (relative to the radius of a typical spring retainer 2510, i.e., comparable to the radius of a valve spring (not shown)). It is further illustrated to the extent depicted. In this embodiment, the increased radius spring retainer 2506 ensures that during uncontrolled movement (especially rotation of the valve bridge body 2302) that portion 2508 of the valve bridge body 2302 that extends between the engine valve stems is The increased radius spring retainer 2506 allows it to come into contact 2511 more quickly, thereby resisting further rotation of the valve bridge body 2302 .

Additionally, FIG. 25 further illustrates the sixth main embodiment in that it shows the feature of an extended valve stem. In the illustrated embodiment, the extended valve stem feature takes the form of a bridge pin 2512 that resides in the second throughbore 2518 . As shown, bridge pin 2512 is free to move up and down on engine valve stem 2514 . In this case, the bridge pin 2512 is free to move upward with the valve bridge body 2302 when the valve bridge body 2302 is in an uncontrolled state. As long as the bridge pin 2512 remains seated in the engine valve stem 2514 despite uncontrolled movement of the bridge pin 2512 and the valve bridge body 2302, the bridge pin 2512 will remain in contact with the engine valve stems 2514, 2516. 2302 alignment is maintained. As shown, the same principles of controlled motion on the engine valve stem 2516 can equally be applied to the bridge pin 2504 aligned with the auxiliary rocker arm. In this embodiment, either or both of the engine valve stems 2514, 2516 have an extended length beyond the spring retainers 2506, 2512, e.g., up to 10 mm extended compared to more typical lengths of 2-3 mm. It may be desirable to have a consistent length.

Figures 26-28 illustrate a valve bridge according to the 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 valve bridge body 2602 that are configured to contact the stems of engine valves 2604,2606. In particular, as best shown in FIG. 28, slots 2608 extend laterally transversely to receptacle 2802 and longitudinal axis 2806 of engine valve stem 2604 (only one shown in FIG. 28). It can have slots. An annular channel 2804 formed in engine valve stem 2604 aligns with slot 2608 when engine valve stem 2604 is aligned and inserted into a corresponding receptacle 2802 . C-clip 2702 is inserted into slot 2608 and engages annular channel 2804 such that C-clip 2702 is retained on engine valve stem 2604 . Once retained on the engine valve stem 2604, the further engagement of the C-clip 2702 with the slot 2608 allows the C-clip 2702 to move the engine out of the receptacle 2802 during uncontrolled movement of the valve bridge body 2602, for example. Disengagement of the valve stem 2604 can be resisted. Although slot 2608 is illustrated in FIGS. 26-28 as extending laterally away from valve bridge body 2602, this is not a requirement. For example, slot 2608 may instead extend perpendicularly out of the plane of FIG. can.

Figure 29 is a side view of a valve bridge according to the eighth main embodiment; In this embodiment, valve bridge body 2902 includes a protrusion 2904 extending downwardly from a lower surface 2908 of valve body 2902 and positioned between at least two engine valve stems (not shown). As further shown, projections 2904 project towards and below at least one spring retainer 2910 such that hook or latch feature 2906 extends beyond the perimeter of at least one spring retainer 2910 . It further comprises at least one hook feature 2906 (only one shown) extending away from portion 2904 . When the valve bridge body 2902 is in an uncontrolled state, the hook feature 2906 contacts the lower surface 2912 of the valve spring retainer 2910 until the valve bridge body is completely disengaged from the engine valve stem. Prevents the valve bridge body 2902 from separating from the engine valve stem. Similar to the fifth embodiment described above in connection with FIG. 25, the increased radius spring retainer 2910 provides a protruding rim of material that extends beyond the circumference of the corresponding valve spring 2914. can be done. In this way, the hook feature 2906 can better engage the spring retainer 2910, thereby better ensuring resistance to disengagement of the valve bridge.

As further shown in FIG. 29, the peripheral shape 2914 of the protrusion 2904 is such that the valve bridge body 2902 may be positioned in one of the engine valves (as in the case of auxiliary valve actuation motion, as depicted in FIG. 29). , right end) to allow tilting without contacting the springs 2914 , 2918 . Based on the illustrated configuration, valve bridge installation is facilitated by installing the left side first and then rotating the valve bridge down onto the rightmost engine valve stem (and corresponding bridge pin 2920). Bridge pin 2920 is held down by a separate auxiliary rocker or its integral actuator piston (not shown), but the latching effect of hook feature 2906 does not allow the bridge to be removed.

Figures 30 and 31 illustrate valve bridges and bridge pins according to the ninth main embodiment. In this embodiment, the valve bridge body 3002 is configured to receive corresponding bridge pins 3008, 3010 between respective arms 3022, 3024 defined by slots 3004, 3006 extending within the valve body 3002. open laterally extending slots 3004 , 3006 . As best shown in FIG. 31, each bridge pin 3008 , 3010 has a receptacle 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 includes a barrel body 3016 and an end cap 3018, 3020 of increased diameter (relative to the barrel body 3016). The slots 3004, 3006 are configured so that the arms 3022, 3024 maintain relatively close clearance to the barrel body 3016 of their respective bridge pins 3008, 3010. The slots 3004,3006, on the other hand, are configured so that the arms 3022,3024 contact the end caps 3018,3020. In this manner, vertical movement of the bridge pins 3008, 3010 is constrained by the spacing 3104 between the upper (and/or lower) surfaces of the arms 3022, 3024 and the complementary surfaces defined by the end caps 3018, 3020. be done. In this manner, the restraint placed on the valve bridge body 3002 by the bridge pins 3008, 3010 prevents disengagement from the engine valve stems 3012, 3014 should the valve bridge body 3002 undergo uncontrolled movement. do. Similar to the third primary embodiment illustrated in FIG. 24, the top surface 3026 of the valve bridge body 3002 is such that the spacing between the top surface 3026 and the end cap 3010 allows more upward movement of the valve bridge body 3002. Note that it can be configured to be more restrictive.

FIG. 32 illustrates a valve actuation system according to prior art techniques. In particular, a folding mechanism similar to that shown in FIG. 1 is deployed on the rocker arm 3202 or pushrod 3204 rather than the valve bridge 3206 as depicted in many of the previously described embodiments. Actuation systems are known. Although the rocker arm 3202 fully engages the rocker shaft 3208, as is known in the art, such a valve actuation system will not allow the valve to sag if excessive lash builds up in the valve train. Bridge 3206 presents an opportunity to enter an uncontrolled state. For example, a sudden collapse in pushrod 3204 may allow the rocker to rotate backward (i.e., toward pushrod 3204), which is equivalent to abrupt elimination of valve lift. If the valve lift lost in this manner was relatively high (eg, 14 mm in some systems), a sudden backward rotation of the rocker arm 3202 would cause the rocker arm 3202 to hit the valve cover 3210 or other object. can let The sudden acceleration of the rocker arm 3202 combined with the rapid acceleration of the valve bridge 3206 under the influence of the valve spring, normally relies on the rocker arm 3202 to maintain engagement of the valve bridge 3206 with the engine valve stem. Backward rotation moves the valve bridge in an uncontrolled manner, possibly resulting in dropout.

To prevent valve bridge 3206 from disengaging in such circumstances, prevent over-rotation of rocker arm 3202 that would otherwise allow valve bridge 3206 to disengage. A stop can be provided for An example of this is illustrated in FIG. 33 where rigid or fixed block 3302 is deployed to prevent rocker arm 3202 from rotating backwards. In the illustrated embodiment, the fixation block 3302 is rigidly attached to the rocker shaft 3208 and, in this example, is a vertical shaft configured to engage a surface of the rocker arm 3202 to prevent over-rotation thereof. Both a surface 3304 and a horizontal surface 3306 are provided. Fixed block 3302 is configured such that vertical surface 3304 and horizontal surface 3306 do not interfere with the normal reciprocating motion (ie, controlled state) of rocker arm 3202 . However, fixed block 3302 is also configured such that vertical surface 3304 and horizontal surface 3306 are positioned to prevent over-rotation of rocker arm 3202 .

For example, the illustrated rocker arm 3202 may include a rear facing surface 3308 defined by a control valve boss formed in the rocker arm 3202 in this case. In the event of a sudden rearward rotation, rear facing surface 3308 contacts vertical surface 3304 and prevents over-rotation of rocker arm 3202 . Similarly, the rocker arm further comprises an upwardly facing surface 3310 . In the event of sudden rearward rotation, rear facing surface 3310 contacts horizontal surface 3306 and prevents over-rotation of rocker arm 3202 . The illustrated embodiment includes both vertical surface 3304 and horizontal surface 3306, although either such surface may be sufficient to prevent over-rotation depending on the configuration of rocker arm 3202. Not a requirement as it is expected to be possible.

Figures 34 and 35 illustrate valve bridges and valve bridge guides according to an eleventh embodiment. In this embodiment, a valve bridge guide 3404 attached to (or integrally formed with) the valve bridge body 3402 is provided. As shown, valve bridge guides 3404 are deployed on sides of valve bridge body 3402 that are not intended to engage engine valves (not shown) that may also be actuated by an auxiliary source of motion. In the illustrated embodiment, valve bridge guide 3404 is shaped as a half-cylinder wall configured to attach to lower surface 3502 of valve bridge body 3402 such that the half-cylinder wall extends downwardly from lower surface 3502 . be. However, it is understood that the valve bridge guide 3404 can be attached to some other surface (eg, the top surface) of the valve bridge body 3402 so long as the half-cylinder wall extends downwardly below the bottom surface 3502 as shown. be.

Figure 36 illustrates the valve bridge and valve bridge guide of Figures 34 and 35 deployed in a valve actuation system. As shown, valve bridge body 3402 spans two engine valve stems and valve bridge guide 3404 encompasses the outer lateral portions of valve spring retainer 3602 . The radius of the half-cylinder wall (preferably centered on or near the longitudinal axis of the corresponding engine valve stem) is such that during normal (i.e. controlled) operation of the valve bridge, the half-cylinder wall It is configured such that no contact occurs between the wall and the valve spring retainer 3602 or the corresponding valve spring 3604 . On the other hand, the radius of the half-cylinder wall is further configured such that during the uncontrolled state of the valve bridge body 3402, the half-cylinder wall contacts the valve spring retainer 3602 but avoids contact with the valve spring 3604. It is 25 and 29, to better ensure contact between the valve spring retainer 3602 and the spring retainer (preferably not the valve spring 3604): An increased radius spring retainer can be used.

As noted above, the present disclosure describes various embodiments and variations of valve bridge guides that may be used to resist, i.e., prevent, minimize, or accommodate uncontrolled movement of the valve bridge. . While various features have been described in conjunction with specific embodiments, those skilled in the art will appreciate that a variety of such features can be incorporated into other embodiments described herein. would do.

Claims (1)

A valve bridge for use with an engine valve assembly of an internal combustion engine, said engine valve assembly comprising at least two engine valves, a first of said at least two engine valves having a bridge pin. actuated by an auxiliary rocker arm through the valve bridge,
A valve bridge body configured to extend between at least two engine valves, said valve bridge body aligned with said first engine valve and receiving said bridge pin. a configured throughbore, wherein the valve bridge body is configured to align with and receive a stem of the second engine valve of the at least two engine valves; a valve bridge body further comprising a receptacle;
A bridge pin boss having said through bore formed therein, said bridge pin boss having a longitudinal length and terminating at a top surface, said longitudinal length being such that said valve bridge extends said at least two 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 in an uncontrolled condition for one engine valve. a bridge pin boss; and a valve bridge.

Images