A compression-release engine brake system operating an exhaust valve of an engine during a compression-release engine braking operation. The compression-release brake system comprises an exhaust rocker arm and a brake reset device disposed in a reset bore formed in the exhaust rocker arm. The brake reset device comprises a reset check valve, a slider-piston slidably disposed in the reset bore and an external slider bias spring biasing the piston foot away from the brake reset device. The external slider bias spring is disposed outside the reset bore and around the piston-slider. The brake reset device permits pressurized hydraulic fluid to flow from a supply conduit to a reset conduit to supply a brake actuation piston when the reset check valve is open. The actuation piston extends and engages the exhaust valve toward the end of a compression stroke of the internal combustion engine, and the brake reset device resets.

A variable valve timing assembly is provided for extending a duration of an intake valve opening. The variable valve timing assembly includes an intake rocker mounted on a pedestal and operable by a cam lobe to open and close the intake valve. The intake rocker includes a lever extension, and a holding member in the pedestal is lockable in position by a hydraulic circuit in the pedestal to contact the lever extension of the intake rocker and hold the intake valve in the open position. A reset pin in the pedestal is actuatable by the cam lobe to release the holding member to allow the intake valve to close.

A valvetrain includes a rocker arm assembly having a rocker arm and an electromagnetic latch assembly. An electromagnet of the latch assembly is housed within a chamber formed by the rocker arm. Passageways suitable for oil cooling of the electromagnet are formed through and inside the rocker arm. In some embodiments, oil for cooling is supplied through a pivot. In some embodiments, oil for cooling is obtained from oil splash. Oil cooling may allow modes of operation such as of dynamic cylinder deactivation and dynamic variable valve actuation to be used without overheating the electromagnet.

In a lash adjuster used for a valve operating mechanism of an internal combustion engine, there is known a lash adjuster constituted by inserting a cylindrical sleeve into a plunger cap for preventing air from entering a high-pressure chamber located at a lower portion of the lash adjuster. However, in the conventional lash adjuster, since the plunger cap is formed with two side holes which are different in height in the axial direction of the plunger cap, it becomes complicated to regulate the side surface the plunger cap which corresponds to a sliding surface. Therefore, it is problems to be solved by the present invention to provide a lash adjuster in which the side surface of the plunger cap can be easily regulated without disturbing the inflow and outflow of oil and whose machining cost can be kept low. The above problems can be solved by a hydraulic lash adjuster in which two or more cap side holes 27c are provided and all of them are disposed in a plane perpendicular to a shaft center of the body 21.

A rocker assembly including a rocker shaft having an outer surface, main oil passage, a first radial passage and a second radial and a rocker arm having a first end and an inner cylindrical surface defining a bore, wherein the rocker shaft is received in the bore to pivotably mount the rocker arm onto the rocker shaft. The rocker arm includes a hydraulic lash adjuster mounted within the first end and a first oil passage having an inlet at the inner cylindrical surface and an outlet in fluid communication with the hydraulic lash adjuster. The inner cylindrical surface is spaced apart from the outer surface of the rocker shaft by a radial clearance, and wherein an inlet to the first oil passage and a first outlet of the first radial passage are in a loaded region of the radial clearance.

A hydraulic lash adjuster assembly constructed in accordance to one example of the present disclosure includes a bucket and a hydraulic lash adjuster. The hydraulic lash adjuster is received in the bucket and has a body, a leakdown plunger and a socket. The leakdown plunger is received in the body. The socket is received by the leakdown plunger. The socket and leakdown plunger define a reservoir therebetween. The socket includes a gravity feed arrangement to feed fluid to the reservoir of the leakdown plunger.

A compression-release brake system for operating an exhaust valve of an engine during an engine braking operation. The compression-release brake system comprises a self-contained compression brake control module (CBCM) operatively coupled to the exhaust valve for controlling a lift and a phase angle thereof. The CBCM includes a casing defining an actuator cavity, a actuation piston disposed outside the casing so as to define an actuation piston cavity between the casing and the actuation piston, and a check valve provided between the actuation piston cavity and a compression brake actuator disposed in the actuator cavity. The actuation piston reciprocates relative to the casing. The compression brake actuator includes an actuator element and a biasing spring. The actuator element selectively engages the check valve when deactivated so as to unlock the actuation piston cavity and disengages from the check valve when activated so as to lock the actuation piston cavity.

A compression-release engine brake system operating an exhaust valve of an engine during a compression-release engine braking operation. The compression-release brake system comprises an exhaust rocker arm and a brake reset device disposed in a reset bore formed in the exhaust rocker arm. The brake reset device comprises a reset check valve, a slider-piston slidably disposed in the reset bore and an external slider bias spring biasing the piston foot away from the brake reset device. The external slider bias spring is disposed outside the reset bore and around the piston-slider. The brake reset device permits pressurized hydraulic fluid to flow from a supply conduit to a reset conduit to supply a brake actuation piston when the reset check valve is open. The actuation piston extends and engages the exhaust valve toward the end of a compression stroke of the internal combustion engine, and the brake reset device resets.

A rocker arm comprising a supply path that communicates with a first lash bore and a first spool bore. A spool is in the spool bore. A hydraulic lash device is in the first lash bore, wherein an outer body is configured to collapse during a first valve lift profile when receiving a low pressure fluid, and wherein the outer body and the inner body are configured to cooperate rigidly when receiving a high pressure fluid during a second valve lift profile. The spool is movable to a first spool position to align the spool notch with a first spool path and a second spool path, and the spool is movable to a second spool position to align the spool notch with the second spool path and an accumulator path. The supply path in to the rocker arm is the only source of fluid to the spool.

An engine system and valvetrain can comprise a rocker shaft combined with a first block, a first cylinder deactivation oil control valve in the first block, a second cylinder deactivation oil control valve in the first block. Also, a second block can be combined with the rocker shaft with a third cylinder deactivation oil control valve and an early exhaust valve opening oil control valve in the second block. The rocker shaft can comprise oil infeeds and oil outfeeds configured for supplying hydraulic pressure to the first and second blocks, the blocks can distribute the pressure to the control valves, and the blocks can return pressure to the rocker shaft. Intake and exhaust rocker arms can receive the returned pressure to actuate valves, and the rockers arms can be arranged line-to-line with no overlap during motion.