Systems for valve actuation in internal combustion engines provide configurations for hydraulic lash adjusters and valve actuation valvetrain components that are particularly suitable for prevention of HLA jacking in dedicated cam environments including Type II valvetrain architectures. In one implementation, a lash adjuster loading component, which may comprise a stroke-limited spring biased piston associated with the main event valvetrain keeps the lash adjuster under a constant compressive force to prevent jacking.

A socket module for a compression release engine brake is provided between an exhaust rocker arm rotating with respect to a rocker arm shaft and a valve bridge in contact with an exhaust valve of an engine. In particular, the socket module includes: a housing which includes an inlet through which brake oil is introduced, a brake piston mounting portion, and a reset member mounting portion communicated with the brake piston mounting portion; a brake piston that is provided to be movable in the brake piston mounting portion; and a reset member that is provided in the reset member mounting portion and that discharges brake oil by selectively contacting a push pin coupled to an upper portion of a cylinder head of the engine.

An engine braking system includes engine braking actuators for adjusting exhaust valve timings to engine braking timings in a cylinder-number braking mode. The system further includes an engine braking controller coupled to a control switch that produces a request indicating a requested cylinder-number braking mode. The engine braking controller is structured to transition exhaust valves to the engine braking timings, determine a control term to adjust intake air pressure for varying a braking power of the engine, and to adjust geometry of an exhaust turbine based on the control term. An adjusted speed of a compressor rotated by the exhaust turbine provides a change to intake air pressure that adjusts the braking power of the engine. Different levels of braking power are provided within different cylinder-number braking modes.

An exhaust valve rocker arm assembly operable in a combustion engine mode and an engine braking mode can include a rocker shaft and a rocker arm. The rocker shaft can define a pressurized oil supply conduit. The rocker arm can receive the rocker shaft and is configured to rotate around the rocker shaft. The rocker arm can have an oil supply passage defined therein. A valve bridge can engage a first exhaust valve and a second exhaust valve. A hydraulic lash adjuster assembly can include first and second plunger bodies, the first plunger body can engage the valve bridge. A pressure relief valve assembly can be configured to selectively release oil from the hydraulic lash adjuster assembly.

A compression-release brake system is provided that includes a lost motion exhaust rocker assembly, an actuation piston, and a reset device. The actuation piston includes an actuation piston body that is slidably received by the rocker arm to define a piston cavity in the rocker arm and is movable between piston retracted and extended positions. The actuation piston is configured to be operatively associated with the exhaust valve to permit unseating of the exhaust valve from the seated state. An actuation piston check valve is configured to move between closed and open positions to permit hydraulic fluid flow through an actuation piston communication port to the piston cavity. The reset device includes a reset check valve and a reset pressure control spring for applying a biasing force to the reset check valve to urge the reset check valve toward an open position.

A compression-release engine brake system for effectuating a compression-release engine braking operation of an internal combustion engine. The compression-release system includes a lost motion exhaust rocker assembly including an exhaust rocker arm, an actuation device including an actuation piston and an actuation cavity, and a reset device including a reset check valve and a slider-piston. Hydraulic fluid in the exhaust rocker arm is locked in the actuation cavity when the reset check valve is in the closed position, and flows through the reset check valve when the reset check valve is in the open position. The slider-piston is associated with the reset check valve so that in an extended position of the slider-piston the reset check valve is free to move toward the closed position, and in a retracted position of the slider-piston the reset check valve is moved to the open position thereof by the slider-piston.

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 control device and method for controlling a compression release brake arrangement is provided. The compression release brake arrangement comprises an exhaust valve actuator assembly, a first actuator valve and a second actuator valve. The method comprises controlling the first and second actuator valves to a first state in which one of the actuator valves is open and the other one is closed. The disclosure further relates to a computer program, a computer readable medium, as well as to a vehicle comprising the control device.

An engine valve actuation mechanism for producing a variable engine valve event includes a cam, a rocker arm, a rocker arm shaft, an eccentric rocker arm bushing, and a bushing actuation device. The eccentric rocker arm bushing is disposed in an axial hole in the rocker arm, the rocker arm shaft being disposed in the eccentric rocker arm bushing with the rocker arm shaft and the eccentric rocker arm bushing having offset axial centerlines. One end of the rocker arm and the cam is connected to form a kinematic pair and the other end of the rocker arm is located above the engine valve with a gap between the cam and the engine valve. The bushing actuation device is placed in the rocker arm and drives the eccentric rocker arm bushing to rotate, and the rotation of the eccentric rocker arm bushing changes the gap to generate the variable engine valve event.

An apparatus for resetting an engine brake to be able to exhibit a braking force by opening an exhaust valve at the close of a compression stroke of an engine to prevent combustion includes a housing configured to introduced with pressurized oil from the engine brake and to discharge the oil to the outside depending on an operation of a rocker arm of the engine brake, a check plate configured to be elastically supported within an inside of the housing to control oil introduced into the housing, a piston configured to be accommodated in the check plate and slid when the inside of the housing is filled with oil to discharge the oil, and a reset pin configured to be elevatably installed at one side of the housing to form a passage through which the oil is discharged from the housing to the outside.