CN113803127B

CN113803127B - Rocker arm assembly

Info

Publication number: CN113803127B
Application number: CN202110914130.6A
Authority: CN
Inventors: 道格拉斯·J·尼尔森; 小詹姆斯·E·麦卡锡; 克沙塔·比什诺伊; 基兰·贝里; 马约·塞卡尔
Original assignee: Eaton Intelligent Power Ltd
Current assignee: Eaton Intelligent Power Ltd
Priority date: 2016-04-07
Filing date: 2017-04-07
Publication date: 2024-02-13
Anticipated expiration: 2037-04-07
Also published as: CN109154216A; CN113803127A; CN114622963B; WO2017177102A1; CN114622963A; DE112017001251T5; CN109154216B

Abstract

The valve train assembly includes a first exhaust valve, a second exhaust valve, and a valve bridge including a body and a lever rotatably connected to the body, the body configured to engage the first exhaust valve, and the lever configured to engage the second exhaust valve. An exhaust valve rocker arm assembly is configured to selectively open the first and second exhaust valves, the exhaust valve rocker arm assembly including an exhaust valve rocker arm having a Hydraulic Lash Adjuster (HLA) assembly connected thereto, the HLA assembly in contact with the valve bridge body. The engine brake rocker arm assembly is configured to selectively open the second exhaust valve and includes an engine brake rocker arm having a combined HLA and additional motion pod connected thereto. The combined HLA and additional locomotion pod is configured to selectively engage and rotate the lever.

Description

Rocker arm assembly

The present application is a divisional application of chinese invention patent application with application date 2017, 4 and 7, application number 201780030890.2, and inventive name "rocker arm assembly".

Cross Reference to Related Applications

The present application claims the benefits of indian patent application 201611012287 filed on 7 of 2016, indian patent application 201611014772 filed on 28 of 2016 and U.S. provisional patent application 62/430,102 filed on 5 of 2016 of 12. The disclosures of the above applications are incorporated herein by reference.

Technical Field

The present disclosure relates generally to a rocker arm assembly for a valve train assembly, and more particularly to a rocker arm assembly having an engine brake bridge.

Background

In addition to wheel braking, compression engine braking may be used as auxiliary braking on relatively large vehicles powered by, for example, heavy or medium duty diesel engines. When the piston in an engine cylinder is close to the top dead center position of its compression stroke, the compression engine brake system is arranged to effect additional opening of the exhaust valve of said cylinder upon start-up, such that compressed air can be released through said exhaust valve. This allows the engine to act as a power consuming air compressor, slowing the vehicle.

In a typical valve train assembly used with compression engine braking, the exhaust valve is actuated by a rocker arm that engages the exhaust valve by means of a valve bridge. The rocker arm rocks in response to a cam on a rotating camshaft and presses down on a valve bridge that itself presses down on an exhaust valve to open the exhaust valve. A hydraulic lash adjuster may also be provided in the valve train assembly to remove any lash or clearance created between components in the valve train assembly.

The background description provided herein is for the purpose of generally presenting the context of the disclosure. Work of the presently named inventors, to the extent it is described in this background section, as well as aspects of the description that may not otherwise qualify as prior art at the time of filing, are neither expressly nor impliedly admitted as prior art against the present disclosure.

Disclosure of Invention

In one aspect of the present disclosure, a valve train assembly is provided. The valve train assembly includes a first exhaust valve, a second exhaust valve, and a valve bridge including a body and a lever rotatably connected to the body, the body configured to engage the first exhaust valve, and the lever configured to engage the second exhaust valve. An exhaust valve rocker arm assembly is configured to selectively open the first and second exhaust valves, the exhaust valve rocker arm assembly including an exhaust valve rocker arm having a Hydraulic Lash Adjuster (HLA) assembly connected thereto, the HLA assembly in contact with the valve bridge body. The engine brake rocker arm assembly is configured to selectively open the second exhaust valve and includes an engine brake rocker arm having a combined HLA and an additional motion pod connected thereto. The combined HLA and additional motor pod is configured to selectively engage and rotate the lever to open the second exhaust valve.

In addition to the foregoing, the valve train assembly may include one or more of the following features: wherein the HLA assembly is in continuous contact with the valve bridge body; wherein the combined HLA and additional motion pod comprises a second HLA assembly and an additional motion assembly configured to move between a retracted position wherein the combined HLA and additional motion pod does not contact the lever and an extended position wherein the combined HLA and additional motion pod contacts the lever and configured to rotate the lever to open the second exhaust valve; wherein the combined HLA and additional locomotion pod is connected to the lever; wherein opening the second exhaust valve performs a braking event actuation; wherein the lever is connected to the body such that rotation of the lever and engagement of the second exhaust valve occurs without rotation of the body; and wherein the body includes a bore within which the lever is at least partially disposed, and wherein the lever is rotatably connected to the body by a bridge pin extending through the body.

In another aspect of the present disclosure, a valve train assembly is provided. The valve train assembly includes a first exhaust valve, a second exhaust valve, and a valve bridge including a body and a lever rotatably connected to the body, the body configured to engage the first exhaust valve, and the lever configured to engage the second exhaust valve. An exhaust valve rocker arm assembly is configured to selectively open the first and second exhaust valves, the exhaust valve rocker arm assembly including an exhaust valve rocker arm having a rigid motion transfer assembly coupled thereto, the rigid motion transfer assembly in contact with the valve bridge body. The engine brake rocker arm assembly is configured to selectively open the second exhaust valve and includes an engine brake rocker arm having a combined HLA and an additional motion pod coupled thereto, the combined HLA and additional motion pod configured to selectively engage and rotate the lever to open the second exhaust valve.

In addition to the foregoing, the valve train assembly may include one or more of the following features: wherein the rigid motion transfer assembly is in continuous contact with the valve bridge body; wherein the rigid motion transfer assembly comprises a rigid body connected to a plug disposed within a socket, the socket contacting the valve bridge body; wherein the rigid motion transfer assembly does not include a hydraulic lash adjustment feature; wherein the combined HLA and additional motion pod comprises a second HLA assembly and an additional motion assembly configured to move between a retracted position wherein the combined HLA and additional motion pod does not contact the lever and an extended position wherein the combined HLA and additional motion pod contacts the lever and configured to rotate the lever to open the second exhaust valve; wherein the combined HLA and additional locomotion pod is directly connected to the lever; and wherein the body includes a bore within which the lever is at least partially disposed, and wherein the lever is rotatably connected to the body by a bridge pin extending through the body.

In another aspect of the present disclosure, a valve train assembly is provided. The valve train assembly includes a first exhaust valve, a second exhaust valve, and a valve bridge including a body and a lever rotatably connected to the body, the body configured to engage the first exhaust valve, and the lever configured to engage the second exhaust valve. An exhaust valve rocker arm assembly is configured to selectively open the first and second exhaust valves, the exhaust valve rocker arm assembly including an exhaust valve rocker arm having a Hydraulic Lash Adjuster (HLA) assembly connected thereto, the HLA assembly in contact with the valve bridge body. The engine brake rocker arm assembly is configured to selectively open the second exhaust valve and includes an engine brake rocker arm having a lost motion capsule (lost motion capsule) coupled thereto, the lost motion capsule configured to selectively engage and rotate the lever to open the second exhaust valve.

In addition to the foregoing, the valve train assembly may include one or more of the following features: wherein the HLA assembly is in continuous contact with the valve bridge body; wherein the lost motion capsule does not include a hydraulic lash adjustment feature; wherein the lost motion capsule is configured to move between an activated position and a deactivated position, wherein in the activated position the lost motion capsule acts as a rigid body configured to transfer motion from the engine brake rocker arm to the lever, thereby rotating the lever and opening the second exhaust valve, and wherein in the deactivated position the lost motion capsule is configured to collapse when the lost motion capsule contacts the lever, so as to absorb motion of the engine brake rocker arm; wherein the lost motion capsule comprises an outer body, a plunger, a latch mechanism, and a spherical pivot; wherein the lost motion capsule is directly connected to the lever; wherein the HLA assembly comprises a housing, a first piston body and a second piston body disposed at least partially within the housing and defining a central chamber therebetween configured to receive a fluid, and wherein the hydraulic actuator assembly further comprises a biasing mechanism disposed between the first piston body and the second piston body; and wherein the lever includes an engagement surface, an opposite side opposite the engagement surface, and a stop flange extending therefrom, wherein the engagement surface is configured to be selectively engaged by the lost motion capsule, the opposite side configured to move upwardly against the body when the engagement surface moves downwardly, and wherein the stop flange is configured to selectively engage an edge of the body that at least partially defines an aperture to limit downward movement of the lever.

Drawings

The present disclosure will become more fully understood from the detailed description and the accompanying drawings, wherein:

FIG. 1 is a plan view of a valve train assembly incorporating a rocker arm assembly including an intake rocker arm assembly, an exhaust rocker arm assembly, and an engine brake rocker arm assembly constructed in accordance with one example of the present disclosure;

FIG. 2 is a perspective view of the valve train assembly shown in FIG. 1, without the intake rocker arm assembly;

FIG. 3 is an exploded view of the exhaust valve rocker arm assembly and engine brake rocker arm assembly of FIG. 1;

FIG. 4 is a cross-sectional view of the engine brake rocker arm assembly shown in FIG. 3.

FIG. 5 is a perspective view of a portion of the rocker arm assembly shown in FIG. 1;

FIG. 6 is a perspective view of a valve bridge assembly of the exhaust valve rocker arm assembly shown in FIG. 1 constructed in accordance with one example of the present disclosure;

fig. 7 is a plan view of a portion of the valve bridge assembly shown in fig. 6.

FIG. 8 is a cross-sectional view of the rocker arm assembly shown in FIG. 5 during actuation of a normal exhaust event;

FIG. 9 is a cross-sectional view of the rocker arm assembly shown in FIG. 5 during actuation of a braking event;

FIG. 10 is a perspective view of another configuration of the rocker arm assembly shown in FIG. 2;

FIG. 11 is a perspective view of yet another configuration of the rocker arm assembly shown in FIG. 2; and

fig. 12 is a cross-sectional view of yet another configuration of the rocker arm assembly shown in fig. 2.

Detailed Description

Referring initially to fig. 1 and 2, a partial valve train assembly constructed in accordance with one example of the present disclosure is shown and generally identified by reference numeral 10. The partial valve train assembly 10 utilizes engine braking and is shown configured for a three cylinder bank portion of a six cylinder engine. However, it should be appreciated that the present teachings are not so limited. In this regard, the present disclosure may be used with any valve train assembly that utilizes engine braking. The partial valve train assembly 10 is supported in a valve train support frame 12 and may include three rocker arms per cylinder.

Specifically, each cylinder includes an intake valve rocker arm assembly 14, an exhaust valve rocker arm assembly 16, and an engine brake rocker arm assembly 18. The exhaust valve rocker arm assembly 16 and the engine brake rocker arm assembly 18 cooperate to control the opening of the exhaust valves and are collectively referred to as a dual rocker arm assembly 20 (fig. 2). The intake valve rocker arm assembly 14 is configured to control movement of the intake valve, the exhaust valve rocker arm assembly 16 is configured to control movement of the exhaust valve in the drive mode, and the engine brake rocker arm assembly 18 is configured to act on one of the two exhaust valves in the engine brake mode, as will be described herein. In alternative constructions, the exhaust valve rocker arm assembly 16 and the engine brake rocker arm assembly 18 may be combined into a single rocker arm, referred to as a combined exhaust and engine brake rocker arm assembly.

The rocker shaft 22 is received by the valve train support frame 12 and supports rotation of the exhaust valve rocker arm assembly 16 and the engine brake rocker arm assembly 18. As described in more detail herein, the rocker shaft 22 may deliver oil to the assemblies 16, 18 during operation. The camshaft 24 includes lift profiles or cam lobes configured to rotate the assemblies 16, 18 to actuate the first and second exhaust valves 26, 28, as described in more detail herein.

As shown in fig. 2, the exhaust valve rocker arm assembly 16 includes a component C1 operatively associated with the valve bridge assembly 32, and the engine brake rocker arm assembly 18 includes a component C2 operatively associated with the movable lever assembly 130 into the valve bridge assembly 32. The components C1 and C2 are configured to (sometimes selectively) transfer motion between their associated rocker arm assemblies 16, 18 and the respective valve bridge assembly 32 and movable lever assembly 130.

As described in greater detail herein, various configurations and/or combinations of components C1 and C2 may provide various engine control techniques. For example, the first configuration shown in fig. 3-5 shows C1 as a Hydraulic Lash Adjuster (HLA) assembly 36 and C2 as an actuator or piston assembly 76 without HLA features. The second configuration shown in fig. 10 shows C1 as HLA assembly 208 and C2 as combined HLA and additional exercise bay 210. The third configuration shown in fig. 11 shows C1 as a rigid motion transfer assembly 310 without HLA features, and C2 as a combined HLA and additional motion pod 312. The fourth configuration shown in fig. 12 shows C1 as the HLA assembly 410 and C2 as the lost motion capsule 412 without HLA features.

Such engine control techniques that may be implemented with the various configurations described above include, but are not limited to: variable Valve Lift (VVL), early Intake Valve Opening (EIVO), early Intake Valve Closing (EIVC), late Intake Valve Opening (LIVO), late Intake Valve Closing (LIVC), early Exhaust Valve Opening (EEVO), early Exhaust Valve Closing (EEVC), late Exhaust Valve Opening (LEVO), late Exhaust Valve Closing (LEVC), a combination of EEVC and LIVO, negative Valve Overlap (NVO), or other engine control techniques.

Referring now further to fig. 2 and 3, the exhaust valve rocker arm assembly 16 will be further described. The exhaust valve rocker arm assembly 16 may generally include an exhaust rocker arm 30, a valve bridge assembly 32, and a Hydraulic Lash Adjuster (HLA) assembly 36.

The exhaust rocker arm 30 includes a body 40, a shaft 42, and a roller 44. The body 40 may receive the rocker shaft 22 and define a bore 48, the bore 48 being configured to at least partially receive the HLA assembly 36. The shaft 42 may be coupled to the body 40 and may receive a roller 44, the roller 44 being configured to be engaged by an exhaust lift profile or cam lobe 50 (fig. 2) of the camshaft 24. Thus, when the roller 44 is engaged by the exhaust lift profile 50, the exhaust rocker arm 30 rotates downward, causing the valve bridge assembly 32 to move downward to engage the first and second exhaust valves 26, 28 (FIG. 2) associated with a cylinder of an engine (not shown).

HLA assembly 36 is configured to occupy any gap between HLA assembly 36 and valve bridge assembly 32. Referring additionally to fig. 8 and 9, in one exemplary embodiment, the HLA assembly 36 may include a plunger assembly 52, the plunger assembly 52 including a down leak plunger or first plunger body 54 and a ball plunger or second plunger body 56. The plunger assembly 52 is received by the bore 48 defined in the rocker arm 30 and may have a first closed end defining a plug 58, the plug 58 being received in a socket 60 that acts against the valve bridge assembly 32. The second plunger body 56 has an opening defining a valve seat 62, and a check ball assembly 64 may be positioned between the first plunger body 54 and the second plunger body 56.

The check ball assembly 64 may be configured to retain oil within a chamber 66 between the first plunger body 54 and the second plunger body 56. A biasing mechanism 68 (e.g., a spring) biases the second plunger body 56 upward (as shown in fig. 8 and 9) to expand the first plunger body 54 to occupy any gap. As the second plunger body 56 is biased upward, oil is drawn through the check ball assembly 64 and into the chamber 66 between the plunger bodies 54, 56. Accordingly, oil may be supplied from the rocker shaft 22 to the chamber within the second plunger 56 through a passage (not shown), and downward pressure may cause the first plunger body 54 to move downward due to the oil in the chamber 66. However, the HLA assembly 36 may have any other suitable configuration that enables the assembly 36 to occupy the gap between the assembly and the valve bridge assembly 32.

Referring now further to fig. 2-4, the engine brake rocker arm assembly 18 will be further described. The engine brake rocker arm assembly 18 may generally include an engine brake rocker arm 70, a shaft 72, a roller 74, an actuator or piston assembly 76, and a check valve assembly 78.

The engine braking rocker arm 70 may receive the rocker shaft 22 and may define a first bore 80 and a second bore 82. The first bore 80 may be configured to at least partially receive the piston assembly 76 and the second bore 82 may be configured to at least partially receive the check valve assembly 78. The shaft 72 may be coupled to the rocker arm 70 and may receive a roller 74, the roller 74 being configured to be engaged by a brake lift profile or cam lobe 84 (fig. 2) of the camshaft 24. Thus, when roller 74 is engaged by cam lobe 84, brake rocker arm 70 rotates downward, causing piston assembly 76 to move downward.

As shown in fig. 3 and 4, the actuator or piston assembly 76 may include a first actuator or piston body 86, a second actuator or piston body 88, a socket 90, a biasing mechanism 92, a stop 94, and a nut 96. The piston assembly 76 may be received by a first bore 80 of the rocker arm 70. The first piston body 86 may include a first closed end defining a plug 98, the plug 98 being received in the socket 90, the socket 90 acting on the valve bridge assembly 32. The second piston body 88 may be secured to the rocker arm 70 by a nut 96, and a stop 94 may be secured to the second piston body 88. The second piston body 88 and the nut 96 may be used as a trim screw to set the initial position of the piston assembly 76.

The biasing mechanism 92 (e.g., a spring) is configured to pull or retract the first piston body 86 upward into the bore 80 to a retracted position. The stop 94 may be configured to limit upward movement of the first piston body 86. Pressurized oil is selectively supplied to a chamber 102 of first piston body 86 through passage 100 (fig. 4) to move piston body 86 downwardly and outwardly from bore 80 to the extended position. When the supply of oil to the gallery 100 is suspended, the first piston body 86 is returned to the retracted position by the biasing mechanism 92.

The check valve assembly 78 is at least partially disposed in the second bore 82 and may include a valve spool or check valve 110, a biasing mechanism 112, a cap 114, and a clip 116. The check valve assembly 78 is configured to selectively supply oil from a passage 118 (FIG. 4) in the rocker shaft 22 to the passage 100. The check valve 110 may be biased to a closed position by a biasing mechanism 112 such that oil is not supplied to the passage 100. When the oil pressure in passage 118 is sufficient to open check valve 110, oil is supplied through passage 100 to actuate piston assembly 76 to the extended position. The clip 116 may nest in a radial groove provided in the second bore 82 to retain the check valve assembly 78 therein.

Many known engines with hydraulic valve lash adjustment have a single rocker arm that actuates those valves through a valve bridge that spans both valves. Engine braking bypasses the bridge and pushes one of the valves, tilting or tilting the valve bridge to open a single valve and blow to the cylinder. However, due to the cocked valve bridge, the HLA may react by extending to occupy the gap formed. This may be undesirable because after a braking event, the extended HLA assembly may then hold the exhaust valve open with some loss of compression and possibly piston contact with the valve.

To overcome this potentially undesirable event, the assembly 10 includes a valve bridge assembly 32, the valve bridge assembly 32 having a movable lever assembly 130 integrated therein. The lever assembly 130 may transmit some of the valve actuation force back to the HLA assembly 36 (via the bridge 32), thereby preventing inadvertent extension of the HLA assembly during the braking event. Thus, the lever assembly 130 allows the valve 26 to open during engine braking operations without allowing the valve bridge assembly 32 to move downward. Furthermore, the lever assembly 130 significantly reduces the actuation force required for a braking event as compared to known systems.

Referring additionally to fig. 6 and 7, in one exemplary implementation, the valve bridge assembly 32 includes a lever assembly 130 disposed within a main bridge body 132. The bridge body 132 includes a first end 134 and a second end 136. The first end 134 may be configured to engage the valve 28 and the second end 136 may include a first aperture 138, a second aperture 140, and a third aperture 142.

As shown in fig. 5, the lever assembly 130 may generally include a lever 150, a bridge pin 152, a valve shoe 154, and a valve shoe pin 156. The lever 150 may be disposed within the first bore 138 and rotatably connected to the bridge body 132 by a bridge pin 152, the bridge pin 152 extending through the second and third bores 140, 142 of the bridge body 132.

The lever 150 includes an engagement surface 158, a first opposing opening 160, a second opposing opening 162, and a stop flange 164. The engagement surface 158 is configured to be selectively engaged by the receptacle 90 of the piston assembly 76. The first opposing opening 160 may receive the bridge pin 152 and the second opposing opening 162 may receive the valve shoe pin 156. The stop flange 164 may be configured to engage a bar 166 (fig. 6 and 7) of the bridge body 132 to limit downward movement of the lever 150 (as shown in fig. 6).

The valve shoe 154 includes a body portion 168 and a connecting portion 170, the connecting portion 170 having an aperture 172 formed therein. The body portion 168 is configured to receive a portion of the valve 26 and the connecting portion 170 is at least partially disposed within the lever 150 such that the connecting portion aperture 172 receives the valve shoe pin 156 to rotatably connect the valve shoe 154 to the lever 150.

Thus, the lever 150 may be selectively engaged at the engagement surface 158, which may cause the opposite side 174 of the lever opposite the surface 158 to rotate and move upwardly about the pin 156 (see fig. 9). This upward movement of the lever end 174 moves the bridge body 132 upward toward the HLA assembly 36 to prevent extension thereof.

Thus, during operation of the rocker arm assembly 20, the exhaust rocker arm assembly 16 may selectively engage the valve bridge body 132 to actuate the valves 26, 28 and perform a standard exhaust event (combustion mode); however, the engine brake rocker arm assembly 18 may selectively engage the lever assembly 130 to actuate only the valve 26 and to perform a braking event actuation (engine braking mode).

The piston assembly 76 is configured to move the first piston body 86 between the retracted position and the extended position. In the retracted position, the first piston body 86 is withdrawn into the bore 80 such that the socket 90 is spaced from and out of contact with the lever engagement surface 158 even when the cam lobe 84 of the camshaft 24 engages the engine brake rocker arm 70.

However, in the extended position, the first piston body 86 extends from the bore 80 such that the socket 90 is positioned to engage the rod engaging surface 158. When the cam lobe 84 of the camshaft 24 engages the engine brake rocker arm 70, the socket 90 rotates the lever about the pin 156 to engage the valve 26 and perform a braking event actuation. Fig. 4 shows the engine brake rocker arm assembly 18 with the piston assembly 76 in an extended position due to the supply of oil from the rocker shaft 22 through the passage 100. In this position, the engine braking event actuation is active, and the piston assembly 76 is configured to engage the lever assembly 130 (fig. 9) of the valve bridge assembly 32. The engine braking event actuation capability may be deactivated by stopping the supply of oil through passages 100 and/or 118, thereby moving piston assembly 76 to the retracted position.

Referring now to fig. 4, 8 and 9, an exemplary sequence of operation of the exhaust valve rocker arm assembly 16 and the engine brake rocker arm assembly 18 will be described.

Fig. 8 shows portions of the assemblies 16, 18 during actuation of a normal exhaust event, wherein the exhaust rocker arm 30 is engaged by the cam lobe 50 of the camshaft 24. Specifically, as the camshaft 24 rotates, the cam lobes 50 engage the rollers 44, which causes the exhaust rocker arm 30 to rotate about the rocker shaft 22. In this motion, the exhaust rocker arm 30 pushes the HLA assembly 36 and moves the valve bridge main body 132 downward to open the first and second exhaust valves 26, 28.

FIG. 9 shows portions of the assemblies 16, 18 during actuation of the braking event, wherein the engine brake rocker arm 70 is engaged by the cam lobe 84 of the camshaft 24. Specifically, as camshaft 24 rotates, cam lobe 84 engages roller 74, which causes brake rocker arm 70 to rotate about rocker shaft 22. When the first piston body 86 is in the extended position, the brake rocker arm 70 pushes the socket 90 downward to engage and cause downward movement of the lever engagement surface 158. This in turn may cause downward movement of the valve seat 154, which opens the valve 26 to brake the engine. Further, as lever 150 pivots about pin 156, lever end 174 moves upward against bridge body 132, which pushes HLA assembly 36 to prevent extension thereof during a braking event.

Fig. 10 illustrates a valve train assembly 200 constructed in accordance with one example of the present disclosure. Valve train assembly 200 may be similar to valve train assembly 10 shown in fig. 2, except that component C1 is HLA assembly 208 and component C2 is a combined HLA and additional motion pod 210. HLA assembly 208 may be similar to HLA assembly 36 described above in that it includes hydraulic fluid to adjust the gap height and is configured to automatically occupy any gap between HLA assembly 208 and valve bridge assembly 32. Further, although not shown, HLA assembly 208 may include similar components to HLA assembly 36. However, HLA assembly 208 is not so limited and may include any suitable structure that enables component 208 to function as described herein.

The combined pod 210 may include an HLA assembly 212 and an additional motion assembly 214.HLA assembly 212 may be similar to HLA assembly 36 described above in that it includes hydraulic fluid for adjusting the gap height and is configured to automatically occupy any gap between pod 210 and valve bridge assembly 32. Further, although not shown, HLA assembly 212 may include similar components to HLA assembly 36. However, HLA assembly 212 is not so limited and may include any suitable structure that enables assembly 212 to function as described herein.

In the exemplary embodiment, additional motion assembly 214 is similar to piston assembly 76 described above, in that additional motion assembly 214 is configured to move between a retracted position and an extended position. In this manner, the additional motion assembly 214 defaults to a retracted position in which it may be withdrawn such that the socket 290 is spaced from and out of contact with the lever engagement surface 158 even when the cam lobe 84 of the camshaft 24 engages the engine brake rocker arm 70. However, when selectively activated to the extended position, the receptacle 290 is positioned to engage the lever engagement surface 158. When the cam lobe 84 of the camshaft 24 engages the engine brake rocker arm 70, the socket 290 rotates the lever 150 about the pin 156 to engage the valve 26 and perform a braking event actuation. As such, this configuration of the valve train assembly 200 provides HLA control on the bridge body 132 through the HLA assembly 208 of the exhaust valve rocker assembly 16, and HLA and additional motion control on the lever 150 through the combined HLA and additional motion pod 210. In other configurations, the receptacle 290 or other portion of the additional motion assembly 214 may be connected to the lever 150 to prevent relative motion therebetween, such as by a clip, press fit into the lever 150, or other suitable means to maintain contact between the additional motion assembly 214 and the lever 150. In this way, retraction of the assembly 214 may lift the stem 150 off of the valve 26 to prevent contact therebetween.

FIG. 11 illustrates a valve train assembly 300 constructed in accordance with one example of the present disclosure. Valve train assembly 300 may be similar to valve train assembly 10 shown in fig. 2, except that component C1 is a rigid motion transfer pod or assembly 310 and component C2 is a combined HLA and additional motion pod 312.

The rigid motion transfer assembly 310 is at least partially disposed within the exhaust rocker arm 30 and includes a body 314 connected to a plug 316 disposed within a socket 318. In the exemplary embodiment, rigid motion transfer assembly 310 does not include a hydraulic lash adjustment feature and transfers motion from the exhaust rocker arm to bridge body 132 to actuate valves 26, 28.

In an exemplary embodiment, the combined HLA and additional motion pod 312 may include an HLA assembly 318 and an additional motion assembly 320.HLA assembly 318 may be similar to HLA assembly 36 described above in that it includes hydraulic fluid for adjusting the gap height and is configured to automatically occupy any gap between chamber 312 and valve bridge assembly 32. Further, although not shown, HLA assembly 318 may include similar components to HLA assembly 36. However, HLA assembly 318 is not so limited and may include any suitable structure that enables assembly 318 to function as described herein.

In the exemplary embodiment, additional motion assembly 320 is similar to piston assembly 76 described above in that additional motion assembly 320 is configured to move between a retracted position and an extended position. In this manner, the additional motion assembly 320 defaults to a retracted position in which it may be withdrawn such that the socket 390 is spaced from and out of contact with the lever engagement surface 158 even when the cam lobe 84 of the camshaft 24 engages the engine brake rocker arm 70. However, when selectively activated to the extended position, the receptacle 390 is positioned to engage the lever engagement surface 158. When the cam lobe 84 of the camshaft 24 engages the engine brake rocker arm 70, the socket 390 rotates the lever 150 about the pin 156 to engage the valve 26 and perform a braking event actuation. Thus, this configuration of the valve train assembly 300 provides non-HLA control on the bridge body 132 through the motion transfer assembly 310 of the exhaust valve rocker arm assembly 16 and HLA and additional motion control on the lever 150 through the combined HLA and additional motion pod 312. In other configurations, the receptacle 390 or other portion of the compartment 312 may be connected to the lever 150 to prevent relative movement therebetween, such as by a clip, press fit into the lever 150, or other suitable means to maintain contact between the compartment 312 and the lever 150. In this way, retraction of the combined pod 312 may lift the rod 150 off of the valve 26 to prevent contact therebetween.

Fig. 12 illustrates a valve train assembly 400 constructed in accordance with one example of the present disclosure. Valve train assembly 400 may be similar to valve train assembly 10 shown in fig. 2, except that component C1 is HLA assembly 410 and component C2 is lost motion capsule 412. HLA assembly 410 may be similar to HLA assembly 36 described above in that it includes hydraulic fluid to adjust the gap height and is configured to automatically occupy any gap between HLA assembly 410 and valve bridge assembly 32. Further, although not shown, HLA assembly 410 may include similar components to HLA assembly 36. However, HLA assembly 410 is not so limited and may include any suitable structure that enables assembly 410 to function as described herein.

In one exemplary embodiment, the lost motion capsule 412 may generally include an outer body 420, a plunger 422, a latch mechanism 424, and a ball pivot 426. The outer body 420 includes an oil communication groove 428 in fluid communication with a plurality of oil ports 430 through a plurality of oil passages 432. The plunger 422 is at least partially disposed within the outer body 420 and is configured to selectively slide within the outer body 420 when the pneumatic chamber 412 is in an unlocked position (not shown). A ball pivot 426 is housed within the plunger 422, and the ball pivot 426 is configured to engage the lever 150. One or more biasing mechanisms 434 (e.g., springs) may be provided between the plunger 422 and the cap 436 to absorb movement of the rocker engine brake rocker arm 70 when the lost motion capsule 412 is in the unlatched position, and the cap 436 may provide a sliding interface with the rocker arm 70. The biasing mechanism 434 may be configured to bias the plunger 422 outward from the outer body 420 and absorb movement of the rocker arm 70 when the lost motion capsule 412 is in the deactivated mode, thereby providing a lost motion feature. However, it should be appreciated that the lost motion 412 is not limited to the described structure and may include any suitable structure that enables the lost motion capsule 412 to function as described herein.

Thus, when in the activated or locked position (shown), the lost motion capsule 412 acts as a rigid or unitary body and transfers motion from the rocker arm 70 to the valve 26 via the lever 150. Conversely, when the air chamber 412 is in the deactivated or unlocked position, the downward movement of the rocker arm 70 and the upward resistance of the lever 150 cause the plunger 422 to slide upward within the outer body 420. The biasing mechanism 434 then absorbs downward movement of the rocker arm 70 without transmitting movement to the lever 150 or the valve 26. Thus, this configuration of the valve train assembly 400 provides HLA control on the bridge body 132 via the HLA assembly 410 and selective lost motion control on the lever 150 via the lost motion capsule 412. In other configurations, other portions of the compartment 412 may be connected to the lever 150 to prevent relative movement therebetween, such as by clips, press-fit into the lever 150, or other suitable means to maintain contact between the compartment 412 and the lever 150.

Described herein are systems and methods for braking an engine. The system includes an exhaust valve rocker arm that cooperates with a valve bridge to actuate two valves to perform an exhaust event. In one aspect, a valve bridge includes a body and a lever integrated therein, the lever rotatable relative to the valve bridge body. The rotatable lever is selectively engageable and rotatable by an engine brake rocker arm to actuate one of the two valves to perform an engine braking event. The exhaust valve rocker arm and the engine brake rocker arm include various combinations of components to provide hydraulic lash adjustment, additional movement to actuate a braking event, and/or lost motion to actuate a braking event.

The foregoing description of the examples has been provided for the purposes of illustration and description. The description is not intended to be exhaustive or to limit the disclosure. Individual elements or features of a particular example are generally not limited to that particular example, but are interchangeable and can be used for a selected example where applicable, even if not specifically shown or described. The individual elements or features of a particular embodiment may also be varied in a number of ways. Such variations are not to be regarded as a departure from the disclosure, and all such modifications are intended to be included within the scope of the disclosure.

Claims

1. A valve train assembly, comprising:

a first exhaust valve;

a second exhaust valve;

a valve bridge comprising a body and a lever rotatably connected to the body, the body configured to engage the first exhaust valve and the lever configured to engage the second exhaust valve;

an exhaust valve rocker arm assembly configured to selectively open first and second exhaust valves, the exhaust valve rocker arm assembly comprising an exhaust valve rocker arm having a hydraulic lash adjuster assembly connected thereto, the hydraulic lash adjuster assembly in contact with a body of the valve bridge; and

an engine brake rocker arm assembly configured to selectively open the second exhaust valve and including an engine brake rocker arm having a lost motion capsule connected thereto, the lost motion capsule configured to selectively engage and rotate the lever to open the second exhaust valve;

wherein the lost motion capsule is configured to move between an activated position and a deactivated position;

wherein in the activated position, the lost motion capsule acts as a rigid body configured to transfer motion from the engine brake rocker arm to the lever, thereby rotating the lever and opening a second exhaust valve;

wherein in the deactivated position, the lost motion capsule is configured to collapse upon the lost motion capsule contacting the lever so as to absorb movement of the engine brake rocker arm; and

wherein the lost motion capsule comprises an outer body, a plunger, a latch mechanism, and a ball pivot.

2. The valve train assembly of claim 1, wherein the hydraulic lash adjuster assembly is in continuous contact with a body of the valve bridge.

3. The valve train assembly of claim 1, wherein the lost motion capsule does not include a hydraulic lash adjustment feature.

4. The valve train assembly of claim 1, wherein the lost motion capsule is directly coupled to the lever.

5. The valve train assembly of claim 1, wherein the lever includes an engagement surface, an opposite side opposite the engagement surface, and a stop flange extending therefrom, wherein the engagement surface is configured to be selectively engaged by the lost motion capsule, the opposite side configured to move upward upon downward movement of the engagement surface, and wherein the stop flange is configured to selectively engage an edge of the body to limit downward movement of the lever.

6. The valve train assembly of claim 1, the outer body comprising an oil communication groove in fluid communication with one or more oil ports extending through the outer body.

7. The valve train assembly of claim 1, wherein the plunger is at least partially disposed within the outer body and configured to selectively slide within the outer body when the lost motion capsule is in the deactivated position.

8. The valve train assembly of claim 1, wherein the ball pivot is housed within the plunger and is configured to engage the lever.

9. The valve train assembly of claim 1, further comprising a biasing mechanism disposed between the plunger and a cap, the biasing mechanism configured to bias the plunger outwardly from the outer body to absorb movement of the engine brake rocker arm when the lost motion capsule is in the deactivated position.

10. A valve train assembly, comprising:

a first exhaust valve;

a second exhaust valve;

an engine brake rocker arm assembly configured to selectively open the second exhaust valve and including an engine brake rocker arm having a lost motion capsule coupled thereto, the lost motion capsule configured to selectively engage and rotate the lever to open the second exhaust valve,

wherein opening the second exhaust valve is actuated for a braking event,

wherein the lever is connected to the body such that rotation of the lever and engagement of the second exhaust valve occurs without rotation of the body, an

Wherein the body includes a bore within which the lever is at least partially disposed.

11. The valve train assembly of claim 10, wherein the hydraulic lash adjuster assembly is in continuous contact with a body of the valve bridge.

12. The valve train assembly of claim 10, wherein the lever is rotatably connected to the body by a bridge pin extending through the body.

13. A valve train assembly, comprising:

a first exhaust valve;

a second exhaust valve;

wherein the lever has no portion overlapping the hydraulic lash adjuster assembly when viewed in the actuation direction of the first and second exhaust valves.