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 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's to change a state of cylinder deactivation between activated and deactivated.

A hydraulic lash adjuster for use in diesel engines including a cylinder head having a first valve, a second valve, and a valve bridge extending between and in contact with both the first valve and the second valve. Where the diesel engine includes a first rocker arm, and where at least one of the first valve and the second valve undergo an oil can valve deflection rate. The hydraulic lash is configured to selectively transmit force between the first rocker arm and the valve bridge, and where the hydraulic lash adjuster is normally in the open configuration, and where the hydraulic lash adjuster changes from the open configuration to a closed configuration at a critical velocity that is greater than the oil can valve deflection rate.

Systems and methods for controlling valves in valve actuation systems in internal combustion engines systems may be particularly suitable for sequencing valve motion in engine environments that combine cylinder deactivation and high-power density (HPD) engine braking. A main event motion system is configured to produce main event motion in one or more valve sets. An engine braking system produces engine braking motion and a cylinder deactivation system selectively deactivates main event motion of the intake and exhaust valves the valve set. A blocking system selectively prevents the cylinder deactivation system from deactivating main event motion of at least one intake valve during the engine braking operation. Thus, main event intake valve motions may be available for braking operations, such as HPD braking where main event intake valve motion may be used to enhance CR braking. One actuator can control deactivation of paired intake and exhaust main event motion.

A rocker assembly for a type III center pivot valvetrain comprises a rocker arm having a cam end, a center pivot bore, and a valve end which includes a first actuator bore and a second actuator bore. The rocker assembly further comprises a a cylinder deactivation actuator arranged in the first actuator bore. The cylinder deactivation actuator comprises a hydraulically actuated latch assembly configured to selectively switch between a latched configuration and an unlatched configuration and a a mechanical lash-setting sleeve distanced from a travel stop defined within the first actuator bore. The cylinder deactivation actuator further comprises a lash step disposed below the mechanical lash-setting sleeve and extending into the first actuator bore. The hydraulically actuated latch assembly is configured to selectively travel between the travel stop and the lash step when the hydraulically actuated latch assembly is in the latched configuration.

An engine brake rocker arm assembly for a valvetrain and operable in an engine drive mode and an engine braking mode. The assembly is configured to selectively open one of first and second exhaust valves in the engine braking mode and includes a brake rocker arm configured to rotate about a rocker shaft, and an engine brake capsule assembly movable between (i) a locked position configured to perform an engine braking operation, and (ii) an unlocked position that does not perform the engine braking operation. A lash setting tool is configured to removably engage the engine brake capsule assembly and move the engine brake capsule to the locked position to enable mechanical lash adjustment while the brake rocker arm is assembled in a valvetrain and the engine brake capsule is assembled in the brake rocker arm.

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 valve actuation system comprises a valve actuation motion source configured to provide main and auxiliary valve actuation motions for actuating at least one engine valve via a valve actuation load path. A lost motion subtracting mechanism is arranged in a valve bridge and configured, in a first default operating state, to convey at least the main valve actuation motion and configured, in a first activated state, to lose the main valve actuation motion and the auxiliary valve actuation motion. Additionally, a lost motion adding mechanism is arranged in a rocker arm and configured, in a second default operating state, to lose the auxiliary valve actuation motion and configured, in a second activated state, to convey the auxiliary valve actuation motion, wherein the lost motion adding mechanism is parallel with the lost motion subtracting mechanism in the valve actuation load path at least during the second activated state.

Valve bridge systems include constraints and guides for managing bridge jump and other uncontrolled valve bridge motion during engine operation. Constraints may include an e-foot collar, an extended portion on the bridge, and a bridge brake pin. Guides may include valve stem tip lead-in chamfers surrounding the valve bridge valve pockets as well as a deflection surface on the bridge extended portion. Methods of configuring valve bridges may include configuring the valve step tip lead-in chamfers based on worst-case positions of the valve bridge defined by one or more or a combination of the constraints provided by the e-foot collar, extended portion and brake pin.

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 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 HLAs to change a state of cylinder deactivation between activated and deactivated.

An exhaust valve opening apparatus such as for an engine compression braking system includes a rocker shaft for supplying control fluid to an controllable valve and for distributing the control fluid to a primary and second piston arrangement that selectively opens an exhaust valve in response to the control fluid being pressurized.