Hydraulic capsule for variable valve actuation

A valvetrain assembly, comprising:

• a first engine valve;
• a second engine valve;
• a valve bridge operatively associated with the first engine valve and the second engine valve;
• and
• a combined exhaust and engine brake rocker arm assembly configured to selectively open the first engine valve and the second engine valve, the combined exhaust and engine brake rocker arm assembly comprising:
• a rocker arm comprising a valve end which includes a first actuator bore;
• and
• an engine brake capsule assembly disposed in the first actuator bore, the engine brake capsule assembly configured to transition between (i) a retracted position in which the engine brake capsule assembly does not engage the valve bridge, and (ii) an extended position in which the engine brake capsule assembly selectively engages the valve bridge so as to open the first engine valve, the engine brake capsule assembly comprising:
• an outer housing comprising:
• a lower chamber, and
• a first bore disposed along a horizontal plane above the lower chamber;
• a plunger defining a bottom end of the lower chamber, the plunger extending out below the outer housing;
• a check ball valve assembly disposed within the lower chamber, the check ball valve assembly including a check ball valve configured to selectively enable hydraulic fluid to flow from the first bore into the lower chamber so as to extend the plunger during a transition of the engine brake capsule assembly from the retracted position to the extended position;
• an oil channel extending through the outer housing, the oil channel configured to direct a flow of the hydraulic fluid out of the lower chamber so as to retract the plunger during a transition of the engine brake capsule assembly from the extended position to the retracted position;
• and
• a spool valve disposed within the first bore, the spool valve configured to translate along a length of the first bore between a first position and a second position such that:
• in the first position, the spool valve blocks access to the check ball valve and opens the oil channel, and
• in the second position, the spool valve blocks the oil channel and exposes the check ball valve to the hydraulic fluid flowing from the first bore.