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 actuator assembly for a variable turbine geometry (VTG) turbocharger is disclosed. The actuator assembly may include an actuator and an actuator linkage having a first end coupled to the actuator and a second end defining a linkage joint. The actuator assembly may further include a VTG lever having a ball stud bore extending through the VTG lever. Additionally, the actuator assembly may include a ball stud including a first end partially disposed within the linkage joint and a second threaded end extending axially through the ball stud bore. Furthermore, a nut may be aligned with the ball stud bore and movably attached to the VTG lever prior to extending the ball stud through the ball stud bore, wherein the ball stud engages with the nut and fastens the ball stud to the VTG lever to operatively couple the VTG lever to the actuator linkage.

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.

A valve actuation system comprises at least one main rocker arm operatively connected to a first engine valve, the at least one main rocker arm configured to receive at least main valve actuation motions. A second rocker arm is operatively connected to a second engine valve, the second rocker arm being configured to receive first auxiliary valve actuation motions. The second rocker arm further comprising a hydraulically-controlled first actuator that can selectively couple or decouple the second rocker arm and the second engine valve thereby permitting or preventing conveyance of the first auxiliary valve actuation motions from the second rocker arm to the second engine valve. A one-way coupling mechanism disposed between the at least one main rocker arm and the second rocker arm permits valve actuation motions to be transferred from the at least one main rocker arm to the second rocker arm, but not vice versa.

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.

A valve assembly for an engine includes a gas exchange valve, a valve guide, and a seal. The gas exchange valve includes a valve stem. The valve guide includes an outer surface having a stem seal retention surface disposed at a seal end thereof. The valve stem extends through the valve guide such that the valve is reciprocally movable over a range of travel along the longitudinal axis with respect thereto. The seal is mounted to the stem seal retention surface of the valve guide such that the seal is in running, sealing engagement with the valve stem. The stem seal retention surface includes a shoulder surface to help retain the seal.

Systems and methods for operating an engine with deactivating and non-deactivating valves are presented. In one example, valves of a cylinder are deactivated in a closed state in response to an indication of degradation of a valve of the cylinder. Further, fuel flow to the cylinder may be stopped via ceasing to inject fuel to the cylinder.

A valve actuation system includes a rocker for conveying motion to an engine valve, a motion source arranged to impart motion to the rocker, rocker stop assembly configured to operate in an activated mode, in which the rocker stop assembly maintains the rocker in a position corresponding to partial valve lift, and a deactivated mode, in which the rocker stop assembly allows the rocker to move to a position corresponding to a fully closed valve position, and a rocker stop reset assembly for resetting the rocker stop assembly to the deactivated mode subsequent to a main event peak lift to thereby achieve late valve closing. A damper assembly may interact with the rocker stop assembly to provide a smooth transition of the rocker and valve motion to a late intake valve closing dwell. A valve catch assembly may control the seating velocity of the at least one valve.

A compression release type engine brake includes a first opening unit and a second opening unit each including an exhaust rocker arm, an adjusting screw provided at an end portion of the exhaust rocker arm, a brake module in which brake oil is selectively and a brake piston mount portion is formed therein, a brake piston which is selectively protruded according to the oil supply inside the brake module, a reset member selectively exhausting the oil in the brake module, and a valve bridge connected to the brake piston and provided with an exhaust valve, and wherein a rocker arm protrusion is formed in the exhaust rocker arm of at least one of the first opening unit and the second opening unit, and the shaft spring presses the rocker arm protrusion and adjusts a distance between the first opening unit and the second opening unit.

A roller hydraulic valve lifter includes a body having a longitudinal central axis and an interior area defined by an inside surface which has a pair of flat surfaces opposite one another and connected by a pair of walls. A first bore, essentially perpendicular to the longitudinal axis, extends through the flat surfaces. A bearing is disposed partially in the interior area. The bearing includes an outer ring having substantially cylindrical exterior and interior bearing surfaces. A shaft extends through the first bore and the outer ring and between the pair of flat surfaces. A plurality of needle rollers is disposed between and rollingly engage the shaft and the cylindrical inner bearing surface. The shaft and the plurality of needle rollers are manufactured from an AISI 52100 alloy steel that is carbo-nitrided. The shaft and the plurality of needle rollers have a surface hardness of a minimum of HRc 65.