A rocker arm assembly for an engine is configured to fit about a pivot shaft that extends along a central axis. The assembly includes an intermediate shaft configured to be rotatably disposed about the pivot shaft. A cam-side arm is pivotable about the central axis and is configured to be driven by a cam. A valve-side arm is pivotable about the central axis and relative to the cam-side arm, and is configured to convert rotation of the rocker arm assembly about the central axis into operation of an engine valve. An annular compressible fluid chamber is disposed between the intermediate shaft and the valve-side arm. When the cam-side arm and the intermediate shaft are engaged, pivoting of the cam-side arm compresses fluid within the chamber, causing corresponding pivoting of the valve-side arm and operation of the valve. The fluid provides hydraulic lash adjustment.

A method of controlling CDA conversion may include determining whether CDA device is in CDA mode driving area according to obtained vehicle operation status signal; preparing, when CDA device is in CDA mode driving area, for operating in the CDA driving mode; performing conversion to CDA mode on each cylinder of the CDA device; and controlling, when CDA device is not in DA mode driving area, vehicle driving according to normal area operation map of the CDA device, wherein at performing of conversion to CDA mode on each cylinder, when converting mode of the CDA device from on-operation mode to an operation mode, after combustion is performed in selected cylinder, first exhaust valve maintains an operation state, and remaining exhaust valves and intake valves are converted to non-operation state to perform an exhaust anti-trap control.

A valvetrain includes a rocker arm assembly having an electromagnetic latch housed in a chamber formed by a rocker arm. The chamber may be a retrofit hydraulic chamber. A flux shifting bi-stable latch provides a sufficiently compact design. Isolation of the magnetic elements within the rocker arm chamber may provide protection from metal particles carried by oil in an operating environment for the rocker arm assembly. Wiring connections to the rocker arms may be made through spring posts on the rocker arms. Connection to the rocker arms may be made with springs that can endure the rapid motion induced by the rocker arms. A wiring harness for the rocker arms may attach to hydraulic lash adjusters of the rocker arm assemblies. The rocker arm assemblies and their wiring may be formed into a unitary module that facilitates installation.

A rocker assembly for a type III center pivot valvetrain comprises a rocker arm comprising a cam end, a center pivot bore, and a valve end. The valve end comprises a first actuator bore and a second actuator bore. A cylinder deactivation actuator is in the first actuator bore. An engine brake actuator is in the second actuator bore. The rocker assembly can be part of a valve assembly and can impart an engine braking function, a cylinder deactivation function, and a main lift function to first and second valves. It is also possible to impart an early exhaust valve opening, a main lift function, and a late exhaust valve closing to the engine braking valve.

A castellation device comprises a shaft surrounded by three castellation members. A first castellation member is rotatably mounted on the shaft and comprises a first end and a second end opposite to the first end. A second castellation member is slidably mounted along the shaft adjacent the first end of the first castellation member. A third castellation member is mounted to the shaft adjacent the second end of the first castellation member. A bias spring is disposed between the second castellation member and the third castellation member and is configured to bias the second castellation member away from the third castellation member. Optionally, an annular shroud can enclose the three castellation members. The first castellation member is rotatable relative to the second and third castellation members between a first position and a second position.

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 method for setting lash on a rocker arm assembly having a lost motion stroke includes: providing a rocker arm having a lost motion shaft including a collar, the lost motion shaft being biased toward a valve bridge by a lost motion spring, the lost motion shaft being translatable along a bore defined in the rocker arm; inserting a feeler gage in an area between the collar and the rocker arm; and adjusting an adjusting screw until a desired lash is attained.

A variable valve lift apparatus to vary lift of a valve disposed at an engine may include an outer body selectively making a lever motion according to rotation of a cam, being adapted such that the valve is connected with one end thereof and a pivot axis of the lever motion is disposed at another end thereof, and forming an inside space, an inner body disposed in the inside space of the outer body and adapted such that one end thereof is rotatably connected with the one end of the outer body, a connecting shaft disposed so as to penetrate the one end of the outer body and the one end of the inner body and connect the outer body with the inner body, and a lost motion spring provided so as to return the inner body which is relatively rotated with the outer body around the connecting shaft.

A variable valve mechanism of an internal combustion engine includes an outer arm, an inner arm, a switching device that switches between a coupled state and a non-coupled state, and a lost motion spring. The lost motion spring has an extending portion extending from the outside of the space to the inside of the space. The extending portion has a contact portion that is in contact with the inner arm in the space and being configured to swing in conjunction with swinging of the inner arm. A through-hole is formed in a vertically intermediate portion of the outer arm such that connecting portions are provided at vertically opposite sides of the through-hole, and a portion of the extending portion, a swinging amount of which is smaller than that of the contact portion, passes through the through-hole that allows the portion to swing therein.

A variable valve operating system assembled in an engine includes a first rocker arm contacting with a valve, a second rocker arm no contacting with any valve, a lost motion spring bringing the second rocker arm into contact with a cam, and switching device for switching the first/second rocker arms to a coupled or uncoupled state. An operation control apparatus for the engine includes element for determining whether or not an engine speed is higher than a first speed at which supply of fuel is allowed to be temporarily stopped, and element for setting a requested quantity of increase/decrease in internal resistance of the engine. When the engine speed is higher than the first speed and an accelerator opening degree is 0%, the switching device switches the first/second rocker arms to the coupled or uncoupled state based on the requested quantity.