Hydraulic capsule for variable valve actuation
A rocker arm assembly includes an engine brake capsule assembly. The engine brake capsule assembly is movable between a retracted position and an extended position to selectively engage a valve bridge to open a first exhaust valve. The engine brake capsule assembly includes an outer housing including a lower chamber and a plunger. The plunger extends out below the outer housing. The engine brake capsule assembly further includes a check ball valve assembly disposed within the lower chamber configured to selectively enable a hydraulic fluid into the lower chamber and an oil channel fluidly coupled to the lower chamber and configured to direct a flow of the hydraulic fluid out of the lower chamber. The engine brake capsule assembly further includes a spool valve configured to selectively block the oil channel.
1 . A rocker assembly, comprising:
a rocker arm comprising a valve end which includes an actuator bore; and
an engine brake capsule assembly disposed in the 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 a valve bridge, and (ii) an extended position in which the engine brake capsule assembly selectively engages the valve bridge so as to open a first exhaust 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 a-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.
2 . The rocker assembly of claim 1 , wherein the first bore is configured to receive the hydraulic fluid from a rocker shaft, and
wherein the rocker shaft is disposed through a center pivot bore of the rocker arm.
3 . The rocker assembly of claim 1 , wherein the first bore intersects the oil channel.
4 . The rocker assembly of claim 1 , wherein the spool valve is coupled to a spring disposed at an end of the first bore.
5 . The rocker assembly of claim 4 , wherein the engine brake capsule assembly further comprises a plug configured to seal the end of the first bore.
6 . The rocker assembly of claim 4 , wherein the spool valve is further configured to compress the spring as the hydraulic fluid is introduced into the first bore.
7 . The rocker assembly of claim 6 , wherein, in the second position, the spool valve is further configured to rest against the end of the first bore in response to an increase in pressure based on the introduction of the hydraulic fluid.
8 . The rocker assembly of claim 7 , wherein the spring is configured to expand and translate the spool valve back to the first position in response to a decrease in pressure based on a reduction of the hydraulic fluid.
9 . The rocker assembly of claim 1 , wherein the engine brake capsule assembly further comprises a shoulder disposed in the first bore, and
wherein, in the first position, the spool valve is further configured to abut the shoulder.
10 . 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.
11 . The valvetrain assembly of claim 10 , wherein the first bore is configured to receive the hydraulic fluid from a rocker shaft, and
wherein the rocker shaft is disposed through a center pivot bore of the rocker arm.
12 . The valvetrain assembly of claim 10 , wherein the first bore intersects the oil channel.
13 . The valvetrain assembly of claim 12 , wherein the spool valve is coupled to a spring disposed at an end of the first bore.
14 . The valvetrain assembly of claim 13 , wherein the spool valve is further configured to compress the spring as the hydraulic fluid is introduced into the first bore.
15 . The valvetrain assembly of claim 14 , wherein, in the second position, the spool valve is further configured to rest against the end of the first bore in response to an increase in pressure based on the introduction of the hydraulic fluid.
16 . The valvetrain assembly of claim 15 , wherein the spring is configured to expand and translate the spool valve back to the first position in response to a decrease in pressure based on a reduction of the hydraulic fluid.
17 . The valvetrain assembly of claim 13 , wherein the engine brake capsule assembly further comprises a plug configured to seal the end of the first bore.
18 . The valvetrain assembly of claim 10 , wherein the engine brake capsule assembly further comprises a shoulder disposed in the first bore, and
wherein, in the first position, the spool valve is further configured to abut the shoulder.