An internal combustion engine system includes an engine with a plurality of pistons housed in respective ones of a plurality of cylinders, an air intake system to provide air to the plurality of cylinders through respective ones of a plurality of intake valves, an exhaust system to release exhaust gas from the plurality of cylinders through respective one of a plurality of exhaust valves. A valve train is provided for cylinder deactivation of a first part of the plurality of cylinders and compression release braking on a second part of the plurality of cylinders.

A rocker arm assembly operable in a first mode and a second mode, the rocker arm assembly selectively opening first and second engine valves based on rotation of a cam shaft having a first cam lobe and a second cam lobe, includes: a rocker shaft; a first rocker arm assembly having a first rocker arm that receives the rocker shaft and rotates around the rocker shaft in the first mode based on engagement with the first cam lobe; a second rocker arm assembly having a second rocker arm that receives the rocker shaft and rotates around the rocker shaft and selectively act on one of the first and second engine valves in the second mode based on selective engagement with the second cam lobe; and a biasing assembly that cooperates with the second rocker arm to bias the second rocker arm to a neutral position.

A rocker arm assembly operable in a first mode and a second mode, the rocker arm assembly selectively opening first and second engine valves based on rotation of a cam shaft having a first cam lobe and a second cam lobe, includes: a rocker shaft; a first rocker arm assembly having a first rocker arm that receives the rocker shaft and rotates around the rocker shaft in the first mode based on engagement with the first cam lobe; a second rocker arm assembly having a second rocker arm that receives the rocker shaft and rotates around the rocker shaft and selectively act on one of the first and second engine valves in the second mode based on selective engagement with the second cam lobe; and a biasing assembly that cooperates with the second rocker arm to bias the second rocker arm to a neutral position.

A rocker arm assembly can comprise a main rocker arm and a latch assembly. A latching arm can control the latch assembly and thereby control the extent to which a secondary rocker arm acts on the main rocker arm. The main rocker arm can comprise a main body configured to rotate around a rocker shaft, a valve end extending from the main body, a reaction end extending from the main body, and a latch bore. A bias pin can extend from the main body. The latch assembly can be configured to selectively rotate in the latch bore. The latch assembly can comprise a first latch end comprising a switch plate configured to receive actuation force on a first side and to receive bias force from the bias pin on a second side. A second latch end can comprise a first latch seat and a second latch seat.

A castellation assembly comprises a lost motion spring assembly, an upper castellation piece, and a lower castellation piece. A spring hat comprises a crown, a pin hole through the crown, and a brim. A lost motion spring is seated against the spring hat.

Upper castellation piece comprises a tubular body, an upper inner rim adjoining the brim, and upper castellation teeth. Lower castellation piece comprises a spring post extending up from a castellation body, the spring post passing through the lost motion spring, and through the pin hole. Lower castellation teeth extend from the castellation body. The lost motion spring is biased against the castellation body to lift the upper inner rim by the brim. A lash screw can house the spring post so that the spring post terminates inside the lash screw. A rocker arm is an example of a castellation assembly installation.

Disclosured herein are apparatus and methods relating to combustion engines. In an example, a combustion engine includes a head and a rocker assembly. The rocker assembly including: a rocker shaft including therein a pressure reservoir, a pedestal support adapted to be fastened to the head and sized and structured to support the rocker shaft, a rocker lever pivotally supported by the rocker shaft, and a hydraulic engine brake mechanism within the rocker lever including a hydraulic control valve configured to selectively actuate an exhaust valve of the combustion engine.

Disclosured herein are apparatus and methods relating to combustion engines. In an example, a combustion engine includes a head and a rocker assembly. The rocker assembly including: a rocker shaft including therein a pressure reservoir, a pedestal support adapted to be fastened to the head and sized and structured to support the rocker shaft, a rocker lever pivotally supported by the rocker shaft, and a hydraulic engine brake mechanism within the rocker lever including a hydraulic control valve configured to selectively actuate an exhaust valve of the combustion engine.

An engine valve actuation system includes engine braking rocker arms each having a hydraulically actuated switch, and an electrohydraulic control system including an actuation fluid supply, an electrically actuated valve adjustable to vary a pressure of actuation fluid supplied from the actuation fluid supply to the hydraulically actuated switches, and an engine braking control unit. The engine braking control unit is structured to command adjusting the electrically actuated valve to adjust the hydraulically actuated switch in each of the engine braking rocker arms at a switching window timing that is varied from engine braking cycle to engine braking cycle to distribute hard handoffs among the engine braking rocker arms.

An engine valve actuation system includes engine braking rocker arms each having a hydraulically actuated switch, and an electrohydraulic control system including an actuation fluid supply, an electrically actuated valve adjustable to vary a pressure of actuation fluid supplied from the actuation fluid supply to the hydraulically actuated switches, and an engine braking control unit. The engine braking control unit is structured to command adjusting the electrically actuated valve to adjust the hydraulically actuated switch in each of the engine braking rocker arms at a switching window timing that is varied from engine braking cycle to engine braking cycle to distribute hard handoffs among the engine braking rocker arms.

An oil supply carrier assembly configured to be mounted to a valve train carrier having a plurality of rocker arms according to the present disclosure includes an oil supply carrier housing having a first oil inlet port and a second oil inlet port. The oil supply carrier housing supports an oil control valve and further includes first, second and third oil supply passages. The first oil supply passage is configured to deliver oil from the first oil inlet port on the valve train carrier to the oil control valve. The second oil supply passage is configured to deliver oil from the valve train carrier to at least one engine brake rocker arm of the rocker arms. The third oil supply passage is configured therein to deliver oil from the second oil inlet port to the rocker arms.