Patent Publication Number: US-2023160324-A1

Title: Valve train assembly

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation under 35 U.S.C. § 120 of U.S. patent application Ser. No. 17/328,138, filed May 24, 2021, which is continuation and claims the benefit under 35 U.S.C. § 365(c) of International Patent Application No. PCT/EP2019/083085, filed Nov. 29, 2019, which claims the benefit of U.S. Provisional Patent Application No. 62/773,804 filed Nov. 30, 2018, U.S. Provisional Patent Application No. 62/780,983 filed Dec. 18, 2018, and U.S. Provisional Patent Application No. 62/811,251 filed Feb. 27, 2019. The disclosures of each of these applications are incorporated herein by reference. 
    
    
     FIELD 
     The present disclosure relates generally to a valve train assembly and, more particularly, to a Type II valve train assembly that can be configurable to employ various operational features such as cylinder deactivation and/or engine braking. 
     BACKGROUND 
     Some internal combustion engines can utilize rocker arms to transfer rotational motion of cams to linear motion appropriate for opening and closing engine valves. Deactivating rocker arms incorporate mechanisms that allow for selective activation and deactivation of the rocker arm. In a deactivated state, the rocker arm may exhibit lost motion movement. However, conventional valve train carrier assemblies must be often modified to provide a deactivating rocker arm function, which can increase cost and complexity. Similarly, valve trains can be configured to incorporate engine brake function. Engine braking can be provided to provide an additional opening of an engine cylinder&#39;s exhaust valve when the piston in that cylinder is near a top-dead-center position of its compression stroke so that compressed air can be released through the exhaust valve. Accordingly, while conventional valve train offerings work for their intended purpose, there remains a need for an improved valve train assembly. For example, it would be desirable to provide a valve train assembly solution for a Type II valve train that is able to selectively provide multiple functionalities including cylinder deactivation and engine brake while also being acceptable for a wide range of engine blocks and valve train carriers. 
     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. 
     SUMMARY 
     A type II valve train assembly that selectively opens first and second intake valves and first and second exhaust valves is provided. The valve train assembly includes an intake rocker arm assembly and an exhaust rocker arm assembly. The valve train assembly is configurable for operation in any combination of activated and deactivated states of engine braking and cylinder deactivation. 
     The intake rocker arm assembly includes a first intake rocker arm, a second intake rocker arm and an engine brake intake rocker arm. A first intake hydraulic lash adjuster HLA is associated with the first intake valve. A second intake HLA is associated with the second intake valve. An intake actuation assembly selectively actuates to alter travel of the first and second intake HLA&#39;s to change a state of cylinder deactivation between activated and deactivated. 
     The exhaust rocker arm assembly includes a first exhaust rocker arm, a second exhaust rocker arm and an engine brake exhaust rocker arm. A first exhaust HLA is associated with the first exhaust rocker arm. A second exhaust HLA is associated with the second exhaust valve. An exhaust actuation assembly selectively actuates to alter travel of the first and second exhaust HLA&#39;s to change a state of cylinder deactivation between activated and deactivated. 
     According to other features, a third intake HLA selectively cooperates with the engine brake intake rocker arm. The intake actuation assembly selectively actuates to alter travel of the third intake HLA to change a state of Miller cycle between activated and deactivated. An engine brake capsule assembly can cooperate with the engine brake exhaust rocker arm. The engine brake capsule moves between expanded and collapsed positions dependent upon an activated and deactivated state of engine braking. The engine brake capsule influences the engine brake exhaust rocker arm to open the first and second exhaust valves in the expanded position. 
     According to other features, the exhaust actuation assembly further comprises a first latch pin, a first cam, a second latch pin and a second cam. The first latch pin selectively engages the first exhaust HLA. The first cam rotates to influence movement of the first latch pin between extended and retracted positions. The second latch pin selectively engages the second exhaust HLA. A second cam rotates to influence movement of the second latch pin between extended and retracted positions. 
     In other features, a lever and a lost motion spring assembly is associated with the first exhaust HLA. The lost motion spring assembly is configured to compress upon rotation of the lever subsequent to movement of the first latch pin to the retracted position. A lost motion device can be associated with the exhaust engine brake rocker arm. The lost motion device can include a piston and a biasing member that biases a roller associated with the exhaust brake rocker arm toward an engine brake cam. A mechanical lash adjustment feature can be configured for cooperation with the engine brake exhaust rocker arm. The mechanical lash adjustment feature can comprise a threaded bolt and nut that allows for mechanical lash adjustment that acts on both of the first and second exhaust rocker arms to adjust lash. 
     In other features, the intake actuation assembly is electromechanically actuated. The exhaust actuation assembly can be electromechanically actuated. The first and second exhaust rocker arms can be formed of stamped metal. The engine brake exhaust rocker arm can define a pair of apertures that receive a pin. The pin can engage both of the first and second exhaust rocker arms and impart motion on the first and second rocker arms based on actuation of the engine brake exhaust rocker arm to open the first and second exhaust valves. At least one of the intake and exhaust actuation assemblies can comprise an electronic latch. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The present disclosure will become more fully understood from the detailed description and the accompanying drawings, wherein: 
         FIG.  1 A  is a first perspective view of a valve train assembly constructed in accordance to one example of the present disclosure; 
         FIG.  1 B  is a second perspective view of the valve train assembly of  FIG.  1 A ; 
         FIG.  2    is a plan view of the valve train assembly of  FIG.  1   ; 
         FIG.  3    is a sectional view of the valve train assembly of  FIG.  2    taken along lines  3 - 3  and shown in normal operating mode without cylinder deactivation activated and on base circle; 
         FIG.  4    is a sectional view of the valve train assembly of  FIG.  3    and shown in normal operating mode without cylinder deactivation activated and on base circle; 
         FIG.  5    is a sectional view of the valve train assembly of  FIG.  3    and shown in normal operating mode without cylinder deactivation activated and at max lift; 
         FIG.  6    is a sectional view of the valve train assembly of  FIG.  3    and shown during cylinder deactivation and at maximum lift; 
         FIG.  7    is a sectional view of the valve train assembly of  FIG.  2    taken along lines  7 - 7  and shown during decompression engine brake and during maximum engine brake lift; 
         FIG.  8    is a sectional view of the valve train assembly of  FIG.  7    and shown with the engine brake rocker arm at maximum lost motion and during drive mode; 
         FIG.  9    is a sectional view of the valve train assembly of  FIG.  2    taken along lines  9 - 9  through the engine brake rocker arm assembly; 
         FIG.  10    is a front view of the engine brake rocker arm assembly of  FIG.  9   ; 
         FIG.  11    is a plan view of the engine brake rocker arm assembly of  FIG.  9   ; 
         FIG.  12    is a sectional view taken through a spherical (tilting) sliding roller of the engine brake rocker arm assembly of  FIG.  11   ; 
         FIG.  13    is a front view of the exhaust valve assembly of  FIG.  1 A  and shown with an exemplary cam assembly; 
         FIG.  14    is a top view of the exhaust valve assembly of  FIG.  1 A ; 
         FIG.  15    is a cross-sectional view of the exhaust valve assembly of  FIG.  1 A  and shown taken through a lost motion assembly used on an exhaust rocker arm and through a lost motion assembly used on an intake rocker arm; 
         FIG.  16 A  is a top perspective view of an exhaust valve train assembly constructed in accordance to another example of the present disclosure; 
         FIG.  16 B  is a cross-sectional view of the valve train assembly of  FIG.  16 A  taken along lines  16 B- 16 B; 
         FIG.  16 C  is a cross-sectional view of the valve train assembly of  FIG.  16 A  taken along lines  16 O- 16 O; 
         FIG.  16 D  is a plan view of the valve train assembly of  FIG.  16 A ; 
         FIG.  17    is a first perspective view of a valve train assembly constructed in accordance to another example of the present disclosure; 
         FIG.  18    is a second perspective view of the valve train assembly of  FIG.  17   ; 
         FIG.  19    is a plan view of the valve train assembly of  FIG.  17   ; 
         FIG.  20    is a sectional view taken along lines  20 - 20  of  FIG.  19   ; 
         FIG.  21    is a sectional view taken along lines  21 - 21  of  FIG.  19   ; 
         FIG.  22    is a sectional view taken along lines  22 - 22  of  FIG.  19    and shown in normal operating mode without cylinder deactivation activated; and 
         FIG.  23    is the sectional view of  FIG.  22    and shown with cylinder deactivation activated. 
     
    
    
     DETAILED DESCRIPTION 
     The following discussion provides a Type II valve train solution for diesel engine that provides a variety of operating functionalities including cylinder deactivation and engine brake. As will become appreciated from the following discussion, the valve train provided herein allows a customer to choose various operating functions on the same valve train for a Type II light duty and medium duty valve train. In the partial valve train example shown in  FIG.  1   , a valve train assembly  10  includes an intake valve train assembly  12  and an exhaust valve train assembly  14 . The intake valve assembly  12  includes components suitable for operation with cylinder deactivation and Miller cycle (that could be used for i-EGR) using electromechanical actuation. Similarly, as shown in  FIG.  1   , the exhaust valve train assembly  14  includes components suitable for operation with cylinder deactivation and engine brake using electromechanical actuation. 
     As will become appreciated herein, the intake and exhaust valve train assemblies  12  and  14  can fulfill a wide range of customer operational requirements while using a common valve train offering  10  that is suitable for acceptance on a wide range of engine blocks and valve train carriers. In this regard, maximum flexibility can be provided to various customers to select what valve functions are important for various applications while using the same valve train offering  10  that mates with a given valve train carrier. In this way, a customer can determine which functions are important to employ, such as but not limited to any combinations of, normally open lash adjuster (NOLA), Miller cycle, engine brake, standard lift, etc. as all of these functions are available in the valve train assembly  10 . As such, the same valve train  10  can be similarly suitable for a customer who wants to employ only one function (such as engine brake) or wants to employ more than one of the above operating functions. In the description herein, each of these functions (engine brake, cylinder deactivation, Miller cycle, etc.) are all selectively operational between “activated” and “deactivated” states. 
     With particular reference to  FIGS.  1 A- 2   , a valve train arrangement  10  is shown positioned on a cylinder block  11 . It will be appreciated that the present disclosure for the various features described herein may be used in various other valve train arrangements. In this regard, the features described herein associated with the valve train arrangement  10  can be suitable to a wide variety of other applications. The intake valve train assembly  12  can generally include a first intake rocker arm  32 , a second intake rocker arm  34  and an engine brake rocker arm  36 . The first intake rocker arm  32  includes a first end that pivots over a deactivating HLA capsule  42 , an intermediate portion having a roller  43  and a second end that actuates a first intake valve  44 . The second intake rocker arm  34  includes a first end that pivots over a deactivating HLA capsule  46 , an intermediate portion having a roller  47  and a second end that actuates a second intake valve  48 . The intake side engine brake rocker arm  36  includes a first end that pivots over a deactivating HLA capsule  50  and an intermediate portion having a roller  52 . As will be described in greater detail herein, the roller  52  can include a spherical sliding roller bearing ( FIG.  12   ). A second end of the intake side engine brake rocker arm  36  engages both second ends of the intake rocker arms  32 ,  34  for concurrently actuating both of the intake rocker arms  32  and  34 . 
     The intake valve train assembly  12  further includes an intake actuation assembly  54 . In the example shown, the intake actuation assembly  54  includes a cam assembly  60  having cams  62 ,  64  and  66  fixed to a camshaft  68  that respectively actuate respective latch pins  72 ,  74  and  76 . As will be described herein, the latch pins  72 ,  74  and  76  move from unactuated positions to actuated positions to preclude and permit expansion of the HLA&#39;s  42 ,  46  and  50 . The intake actuation assembly  54  can be an electromechanical actuation assembly that is actuated by an actuation device  78  ( FIG.  1 A ). In other examples, the intake actuation assembly can be configured differently. For example, the intake actuation assembly can alternatively include an electronic latch (e-latch) having a solenoid on a latch pin coupled to a deactivating lash adjuster. In some arrangements, an e-latch can be accommodated successfully in reduced packaging constraints. 
     With continued reference to  FIGS.  1 A- 2    and additional reference to  FIGS.  3 - 8   , additional features of the instant application will be described. A lost motion spring assembly  80  includes a biasing member  82  that biases a lever arm  86  that extends generally between the lost motion spring assembly  80  and the HLA  46 . In the valve train assembly  10  described herein, each of the rocker arms  32  and  34  (on the intake side) as well as rocker arms  132  and  134  (on the exhaust side) are configured with a lost motion spring assembly. Returning now to the description of the lost motion spring assembly  80  in  FIG.  3   , further description will be made with the understanding that the lost motion spring assemblies associated with the rocker arms  32 ,  132  and  134  operate similarly. When the cam  64  rotates to a position to allow the latch pin  74  to retract, the HLA  46  is permitted to move downwardly thereby rotating the lever arm  86  and compressing the spring  82  of the lost motion spring assembly  80 . While not specifically described herein, it will be appreciated that the rocker arm  32  also communicates with a lost motion spring assembly  90  ( FIG.  1 B ) that provides the same functionality as the lost motion spring assembly  80  but for the rocker arm  32 . 
     Returning to  FIGS.  1 A- 2   , the exhaust valve train assembly  14  can generally include a first exhaust rocker arm  132 , a second exhaust rocker arm  134  and an engine brake rocker arm  136 . The first exhaust rocker arm  132  includes a first end that pivots over a deactivating HLA capsule  142 , an intermediate portion having a roller  143  and a second end that actuates a first exhaust valve  144 . The second exhaust rocker arm  134  includes a first end that pivots over a deactivating HLA capsule  146 , an intermediate portion having a roller  147  and a second end that actuates a second exhaust valve  148 . The exhaust side engine brake rocker arm  136  includes a first end that pivots over an engine brake castellation type capsule assembly  150  ( FIG.  1 A ) and an intermediate portion having a roller  152 . 
     As best shown in  FIGS.  7  and  9   , the exhaust side engine brake rocker arm  136  further includes a foot  154  that engages a lost motion device  156 . The lost motion device  156  includes a piston  158  and biasing member  159  that biases the roller  152  against the engine brake cam. The roller  152  can also be a spherical sliding roller bearing. The roller  152  can be used to compensate for inevitable differences and to guarantee low contact stress with the cam and the cylinder roller tire. A second end of the exhaust side engine brake rocker arm  136  engages both second ends of the exhaust rocker arms  132 ,  134  for concurrently actuating both of the exhaust rocker arms  132 ,  134 . The exhaust side engine brake rocker arm  136  also includes a mechanical lash adjustment feature  170 . The mechanical lash adjustment feature  170  can be a treaded bolt  172  and nut  173  ( FIG.  9   ) that allows for mechanical lash adjustment that acts on both of the exhaust rocker arms  132  and  134 . In one example, rotation of the nut  173  can translate the threaded bolt  172  upward and downward thereby changing a rotational position of the rocker arm  136  and a resulting positional engagement with both of the exhaust rocker arms  132  and  134  to adjust lash. 
     The engine brake capsule assembly  150  moves between a first activated position and a second deactivated position. The engine brake capsule  150  is added motion based decompression engine brake. In the activated position, engine braking is active. In the deactivation position, engine braking is not active. In the activated position ( FIG.  7   ), the engine brake capsule assembly  150  is expanded causing rotation of the engine brake arm  136  and opening of the exhaust valves  144  and  148 . In the deactivated position ( FIG.  8   ), the engine brake capsule assembly  150  is collapsed and the engine brake arm  136  is not rotated and the engine valves  144  and  148  are not influenced by the engine brake rocker arm  136 . The engine brake capsule assembly  150  can move between the expanded and collapsed position by way of an actuator assembly. Further description of the operation of the engine brake capsule assembly  150  may be found in commonly owned PCT Application WO/2019/133658 which is expressly incorporated herein by reference. It will be appreciated that while the instant application has been described as using the engine brake capsule assembly  150 , other means may be incorporated for moving the engine brake rocker arm  136  between activated and deactivated positions. 
     The exhaust valve train assembly  14  further includes an exhaust actuation assembly  174 . In the example shown, the exhaust actuation assembly  174  includes a cam assembly  180  having cams  182  and  184  fixed to a camshaft  188  that respectively actuate latch pins  192  and  194 . The latch pins  192 ,  194  move from unactuated positions to actuated positions to preclude and permit expansion of the HLA&#39;s  142  and  146 . The exhaust actuation assembly  174  can be an electromechanical actuation assembly that is actuated by an actuation device  198 . The exhaust actuation assembly  174  can alternatively include an electronic latch (e-latch) having a solenoid on a latch pin coupled to a deactivating lash adjuster as described above. 
     With particular reference now to  FIGS.  3 - 5   , a lost motion spring assembly  210  will be described. The lost motion spring assembly  210  includes a biasing member  212  that biases a lever arm  216  that extends generally between the lost motion spring assembly  210  and the HLA  146 . When the cam  184  rotates to a position to allow the latch pin  194  to retract, the HLA  146  is permitted to move downwardly thereby rotating the lever arm  216  and compressing the spring  212  of the lost motion spring assembly  210 . When a cam  230  rotates it will push the roller  147  associated with the rocker arm  134 . Because the latch pin  194  is engaged to the HLA  146 , the HLA  146  operates normally to take up lash on the rocker arm  134  while the rocker arm  134  pivots about the HLA  146  and opens the valve  148  (from a closed position shown in  FIG.  4    on the base circle, to an open position shown in  FIG.  5    at maximum lift). Notably, the lost motion spring assembly  210  remains essentially static between valve closed ( FIG.  4   ) to valve open ( FIG.  5   ). The latch pin  194  takes up the axial load of the HLA  146 . 
     With reference now to  FIG.  6   , the valve train assembly  14  is shown with cylinder deactivation active. When cylinder deactivation is active, the latch pin  194  is translated to a retracted position (rightward in  FIG.  6   ) based on rotation of the cam  184 . A latch pin spring  240  urges the latch pin  194  to the retracted position shown in  FIG.  6    when the cam  184  is rotated to the position shown in  FIG.  6   . When the latch pin  194  is in the retracted position, the HLA  194  translates downwardly causing the lever  216  to rotate (clockwise in the example shown) which causes the spring  212  to compress. Explained further, when the cam  230  is at maximum lift with cylinder deactivation active in  FIG.  6   , the rocker arm  134  no longer rotates about the HLA  146  (like described above with respect to  FIG.  5   ), and instead, the rocker arm  134  collapses the HLA  146  without opening the valve  148 . As the cam  230  continues to rotate, the lost motion spring  212  expands causing the lever  216  to rotate back to a position shown in  FIG.  3    while returning the HLA  146  back to the position shown in  FIG.  3   . 
     While not specifically described herein, it will be appreciated that the rocker arm  132  also communicates with a lost motion spring assembly  220  ( FIG.  1 B ) that provides the same functionality as the lost motion spring assembly  210  but for the rocker arm  132 . Moreover, the operation of the latch pin  94  and its interaction with the HLA  146  is also carried out with the latch pins  72 ,  74  and  76  associated with the cam assembly  60  on the intake actuation assembly  54 . In this regard, rotation of the cams  62 ,  64  and  66  influence translation of the latch pins  72 ,  74  and  76  into engagement with respective HLA&#39;s  42 ,  46  and  50 . The latch pins  72 ,  74  and  76  move from unactuated positions to actuated positions to preclude and permit expansion of the HLA&#39;s  42 ,  46  and  50 . When cylinder deactivation is active, the latch pins  72  and  74  are translated to a retracted position based on rotation of the respective cams  62  and  64 . Latch pin springs  250 ,  252  urge the latch pins  72  and  74 , respectively to the retracted position. When the latch pins  72  and  74  are in retracted positions, the HLA&#39;s  42  and  46  translate downwardly as described above with respect to the HLA  194 . The rocker arms  32  and  34  ultimately collapse the HLA&#39;s  42  and  46  without opening the valves  44  and  48  when cylinder deactivation is active. 
     In one configuration, the latch pin  76  can actuate between activated and deactivated states based on a desire to operate the intake valve train  12  in a Miller cycle. In this regard, the latch pin  76  can move between engaged and disengaged position with the HLA  50  to influence the rocker arm  36  to change a state of the valves  44  and  48  suitable to satisfy Miller cycle. As is known, Miller cycle can be achieved by either closing the intake valves earlier than a normal or Otto Cycle with a shorter than normal intake valve lift duration, or by closing the intake valve later by a longer than normal intake valve lift profile. 
     With particular reference to  FIGS.  16 A- 160   , a type II valve train arrangement  300  is shown positioned on a cylinder block. It will be appreciated that the present disclosure for the various features described herein may be used in various other arrangements. In this regard, the features described herein associated with the valve train arrangement  300  can be suitable to a wide variety of applications. The valve train arrangement  300  can generally include rocker arms  312  each having a deactivating hydraulic lash adjuster (HLA) capsule  314 . The rocker arms  312  may be roller finger followers (RFF). One overhead cam lobe  350  drives each rocker arm  312 . A first end of the rocker arm  312  pivots over the deactivating HLA capsule  314 , and a second end of the rocker arm  312  actuates a valve  316 . The deactivating HLA capsule  314  can be selectively deactivated to prevent actuation of the valve  316 . 
     The valve train arrangement  300  is configured to selectively perform an engine braking operation and includes an engine braking rocker arm assembly  324  including an engine brake rocker arm  326  disposed between the rocker arms  312 . In one example, one or more of the rocker arms  312 ,  326  can be fabricated from a stamped material rather than cast. As illustrated, the engine braking rocker arm assembly  324  can generally include the engine brake rocker arm  326 , a capsule assembly  354 , and a pin  356 . The engine brake rocker arm  326  includes a first end  358 , a second end  360 , and a roller  362  operatively associated with an overhead cam lobe  364  to drive the engine brake rocker arm  326 . The first end  358  can include a lash adjustment pin  359  operatively associated with the capsule assembly  354 . In some examples the capsule assembly  354  can be a castellation type deactivating capsule similar to described above. 
     In the example embodiment, the second end  360  includes a pair of apertures  366  configured to receive the pin  356  therethrough. The pin  356  is able to at least partially rotate within the apertures  366 . The pin  356  includes ends  368  each with a flat or substantially flat surface  370  configured to engage an upper surface of one of the rocker arms  312 . When the engine brake rocker arm  326  is driven by the overhead cam lobe  364 , the second end  360  is rotated downward. As such, the pin  356  engages both rocker arms  312  and imparts the downward movement to the rocker arm  312  to simultaneously actuate the valves  316  to perform the engine braking operation. 
     Turning now to  FIGS.  17 - 23   , a valve train arrangement described in accordance to another example of the present disclosure is shown and generally identified at reference  410 . As will become appreciated, the valve train arrangement  410 , as with the valve train arrangement  10  above, can offer Type II cylinder deactivation, engine brake and hydraulic lash adjustment. The partial valve train arrangement  410  includes an intake valve train assembly  412  and an exhaust valve train assembly  414 . The intake valve train assembly  412  includes an intake rocker arm  432  that acts on a guided bridge  434 . The guided bridge  434  extends to open first and second intake valves  444  and  448 . A deactivating HLA  436  can be actuated for cylinder deactivation by an intake actuation assembly  454 . The intake actuation assembly  454  includes an electronic latch (e-latch) having a latch pin  472 . The latch pin  472  moves between an unactuated position to an actuated position to preclude and permit expansion of the HLA  436 . 
     The exhaust valve train assembly  414  includes an exhaust rocker arm  532  and an engine brake rocker arm  536 . The exhaust rocker arm  532  acts on a guided bridge  534 . The guided bridge  534  extends to open first and second exhaust valves  544  and  548 . The engine brake rocker arm  536  includes a foot  554  that engages a lost motion device  556 . An engine brake hydraulic capsule  550  can engage an end of the engine brake rocker arm  536  and move between extended and retracted positions depending upon engine brake being activated or deactivated. 
     With particular reference now to  FIG.  22   , a lost motion spring assembly  610  will be described. The lost motion spring assembly  610  includes a biasing member  612  that biases a lever arm  616  that extends generally between the lost motion spring assembly  610  and the HLA  436 . When the latch pin  472  is retracted ( FIG.  23   ), the HLA  436  is permitted to move downwardly thereby rotating the lever arm  616  and compressing the spring  612  of the lost motion spring assembly  610 . When a cam  630  rotates it will push the roller  547  associated with the rocker arm  432 . Because the latch pin  472  is engaged to the HLA  436 , the HLA  436  operates normally to take up lash on the rocker arm  432  while the rocker arm  432  pivots about the HLA  436  and opens the valves  444 ,  448 . 
     With reference now to  FIG.  23   , the valve train assembly  412  is shown with cylinder deactivation active. When cylinder deactivation is active, the latch pin  472  is translated to a retracted position (leftward in  FIG.  23   ) based on a signal sent to the e-latch. When the latch pin  472  is in the retracted position, the HLA  436  translates downwardly causing the lever  216  to rotate (clockwise in the example shown) which causes the spring  612  to compress. Explained further, when the cam  630  is at maximum lift with cylinder deactivation active in  FIG.  23   , the rocker arm  432  no longer rotates about the HLA  436  (like described above with respect to  FIG.  22   ), and instead, the rocker arm  432  collapses the HLA  436  without opening the valves  444 ,  448 . As the cam  630  continues to rotate, the lost motion spring  612  expands causing the lever  616  to rotate back to a position shown in  FIG.  22    while returning the HLA  436  back to the position shown in  FIG.  22   . As can be appreciated, while the intake actuation assembly  454  has been described, an exhaust actuation assembly  574  is constructed similarly for performing similar function relative to an HLA  575 . 
     The configuration of the valve train assembly  410  shown in  FIGS.  17 - 23    provides reduced hardware content over the valve train assembly  10  above. In particular, one deactivating HLA is needed for each pair of valves by incorporating the respective guided brides. Further, the intake and exhaust actuation assemblies  454  and  574  are implemented having an e-latch (or can be electromechanically actuated) for cylinder deactivation and hydraulic for engine braking. 
     The foregoing description of the examples has been provided for purposes of illustration and description. It 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, where applicable, are interchangeable and can be used in a selected example, even if not specifically shown or described. The same may also be varied in many 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.