Integrated rocker for engine braking with hydraulic lash adjuster

A method of operating a valvetrain system comprising an exhaust valve rocker arm assembly, the method comprising, in an engine braking enabled mode:

• extending a first plunger body of a brake capsule to a first position, the exhaust valve rocker arm assembly comprising the brake capsule and a lost motion mechanism, the first plunger body in the first position acting on a valve bridge during rotation of a rocker arm to a first angle to open a first exhaust valve by a predetermined distance, a second exhaust valve remaining closed, wherein the brake capsule comprises a capsule locking mechanism comprising a selectively actuated locking pin configured to engage a groove in the first plunger body of the brake capsule, thereby constraining the first plunger body in a collapsed state when engine braking is disabled, to reduce redundant hydraulic fluid cycling through the brake capsule during non-braking operation;
• and
• causing a lost motion shaft of the lost motion mechanism to act on the valve bridge, subsequent to opening of the first exhaust valve by the predetermined distance and based on further rotation of the rocker arm, to open the second exhaust valve while further opening the first exhaust valve, wherein a hydraulic lash adjuster comprises a second plunger body integrated with a spigot coupled to a socket of the valve bridge, wherein a portion of the second plunger body is positioned between a bias member and the spigot, wherein the bias member extends beyond the second plunger body, and wherein the portion of the second plunger body abuts the lost motion shaft,
• while continually compensating for lash between the lost motion shaft and the valve bridge based on operation of the hydraulic lash adjuster integrated into the lost motion mechanism.

A valvetrain system of an engine, the valvetrain system capable of selectively engaging an engine braking enabled mode or an engine braking disabled mode, the valvetrain system comprising:

• an exhaust camshaft provided with an engine braking profile;
• an exhaust valve rocker arm assembly operatively coupled with the exhaust camshaft and selectively operable in at least the engine braking enabled mode and the engine braking disabled mode;
• a valve bridge;
• and
• a plurality of exhaust valves comprising a first exhaust valve and a second exhaust valve, the plurality of exhaust valves configured to be selectively acted upon by the valve bridge,
• wherein the exhaust valve rocker arm assembly further comprises:
• a rocker arm configured to rotate about a rocker shaft;
• a brake capsule disposed on the rocker arm and comprising:
• a first plunger body selectively movable between a first position and a second position, the first plunger body extending in the first position to act on the first exhaust valve through the valve bridge, and
• a capsule locking mechanism comprising a selectively actuated locking pin configured to engage a groove in the first plunger body of the brake capsule, thereby constraining the first plunger body in a collapsed state when engine braking is disabled, to reduce redundant hydraulic fluid cycling through the brake capsule during non-braking operation;
• and
• a lost motion mechanism disposed on the rocker arm comprising a lost motion shaft and a hydraulic lash adjuster integrated into the lost motion mechanism, the lost motion shaft configured to translate along a lost motion receiving passage for selectively transmitting motion of the rocker arm to the valve bridge, wherein the hydraulic lash adjuster comprises a second plunger body integrated with a spigot coupled to a socket of the valve bridge, wherein a portion of the second plunger body is positioned between a bias member and the spigot, wherein the bias member extends beyond the second plunger body, and wherein the portion of the second plunger body abuts the lost motion shaft.