A switching roller finger follower comprises an inner arm assembly. A pair of outer arms surround the inner arm assembly. A pivot axle connects the inner arm assembly to pivot with respect to the pair of outer arms from a starting position to a lost motion position. A latch assembly comprises a latch selectively movable from a latched position latching the inner arm assembly to move dependent with the outer arms and an unlatched position unlatching the inner arm assembly to pivot independent of the outer arms. A stop pin spans between the pair of outer arms and through an inner port in an axle of inner arm assembly. The stop pin comprises a clearance fit with the inner port, and the stop pin is configured pivotable independent of the outer arms. At least one return spring biases the stop pin toward the starting position.

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.

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 valvetrain for an internal combustion engine includes a camshaft, an electromagnetic latch assembly, a rocker shaft, and a rocker arm assembly. The rocker arm assembly may include a cam follower configured to engage a cam mounted on the camshaft as the camshaft rotates and a rocker arm configured to rotate on the rocker shaft. The electromagnetic latch assembly may include a pin translatable between a first position and a second position and an electromagnet that causes the pin to actuate. The movement of the pin may provide mode switching for a switching rocker arm, a cylinder deactivating rocker arm, or an engine brake rocker arm. The electromagnet is powered by a circuit that passes through the rocker shaft. The electromagnet may be mounted to the rocker shaft. Running the circuit through the rocker shaft allows the electromagnet to be powered with wiring that remains stationary.

A rocker arm assembly selectively opening first and second engine valves. The assembly includes a rocker arm and a valve bridge operably associated with the rocker arm and including a main body and a lever rotatably coupled to the main body. The main body is configured to engage the first engine valve, and the lever is configured to engage the second engine valve.

A system for monitoring operation of an internal combustion engine having a rocker arm assembly for actuating an engine valve is disclosed. The rocker arm assembly includes a first arm with a first end and a second end, at least one slider pad connected to the first arm near the second end of the first arm, a second arm also having a first end pivotally connected near the first end of the first arm along a pivot axle, a latch that when latched secures the first arm relative to the second arm in a latched mode, and when unlatched allows the first arm to move relative to the second arm in an unlatched mode. The system also employs a sensor attached to one of the arms that can detect when the arms are moving relative to each other, and adapted to provide a signal indicating the detected movement.

A switching roller finger follower (SRFF) assembly for valve actuation comprises an outer arm, an inner arm, an inner roller, a bearing axle and a pair of outer rollers. The outer arm is pivotally coupled to a pivot axle. The inner arm is at least partially disposed within the outer arm and pivotally coupled to the pivot axle. The inner roller assembly comprise a bushing and an outer ring. The bushing defines a curved slot therein. The bushing is fixed to the inner arm. The outer ring is configured to rotate around the bushing. The bearing axle extends through the curved slot. The pair of outer rollers are disposed on each end of the bearing axle.

Several devices are disclosed that can be usable together or used in other valvetrains. Disclosed herein are a rocker arm assembly, compliance capsules for a switchable capsule of the rocker arm, actuators, and support structures for the actuators. The alternative compliance capsules can be electromechanically actuated by the alternative actuators, which are hung over the rocker shaft by the support structure. A cam actuator can be in addition to an overhead cam rail and in addition to the rocker shaft. The cam actuator can be configured with a compliance capsule so that the switching of the switchable capsule is mechanically linked and less reliant on precise electrical signal timing.

A rocker arm assembly can comprise a rocker tube configured to be positioned around a rocker shaft, the rocker tube comprising a retention mechanism. A first rocker arm can be press-fit to the rocker tube. A second rocker arm can be pivotably mounted around the rocker tube and retained on the rocker tube by the retention mechanism. An alternative rocker arm assembly, that can be combined with the first rocker arm assembly, can comprise a first and second rocker am and a plate fixed to the first rocker arm. The plate can comprise an extension extending over the second rocker arm. A lost motion spring can be installed between the second rocker arm and the extension.

A valve actuation system comprising a valve actuation motion source configured to provide a main event valve actuation motion to at least one engine valve via a main motion load path that comprises at least one valve train component. The valve actuation system further includes a lost motion component arranged within a first valve train component in the main motion load path, the lost motion component being controllable to operate in a motion conveying state or a motion absorbing state. The valve actuation system also comprises a high lift transfer component arranged in the main motion load path, with the high lift transfer component being configured to permit the main motion load path to convey at least a high lift portion of the main event valve actuation motion when the lost motion component is in the motion absorbing state.