A camshaft for a multiple-cylinder internal combustion engine may include a sliding element comprising at least two cam elements, as well as a splined shaft that extends in an axial direction and on which the sliding element is received. The sliding element may comprise an internal spline system that interacts with an external spline system of the splined shaft such that the sliding element is seated fixedly on the splined shaft so as to rotate with the splined shaft. The sliding element may be received on the splined shaft such that the sliding element can, at least initially, be displaced axially. For axially-fixing the sliding element to the splined shaft, the sliding element may include a positively locking connection that is configured in the axial direction and is produced by way of at least one calked connection between the sliding element and the splined shaft. It should be understood that many camshafts include more than one sliding element.

A camshaft may include a shaft as well as a sliding element that is disposed on the shaft such that the sliding element is axially displaceable along a shaft axis. The shaft may comprise an external tooth for transmitting torque between the shaft and the sliding element. The external tooth may engage a mating tooth geometry formed in a passage of the sliding element. The sliding element on its axial end faces may comprise bearing collars that with the shaft form radial supporting bearings of the sliding element on the shaft. Further, the shaft may comprise cylindrical bearing portions for forming the radial supporting bearings, wherein the bearing portions can be configured with a diameter that is smaller than a diameter circumscribed by tips of the mating tooth geometry that protrude into the passage of the sliding element.

A valve train assembly includes a rocker arm assembly, and axial shifting cam assembly, and a lost motion device. The axial shifting cam assembly is movable between a first axial position and a second axial position on a camshaft, the cam assembly having a first cam having a first lobe, and a second cam having a second lobe. The first and second lobes are configured to each selectively engage the rocker arm assembly to respectively perform a first and a second discrete valve lift event. The lost motion device is operably associated with the rocker arm assembly and configured to perform a third discrete valve lift event, distinct from the first and second valve lift events.

A cam system for operating a first engine valve and a second engine valve includes translatable first and a second sliding lobe packs. The first sliding lobe pack operates the first engine valve with one of a high lift lobe, a low lift lobe, and a zero lift lobe. The second sliding lobe operates the second engine valve with one of a high lift lobe or one of two low lift lobes. A shift barrel has a first groove configured to translate the first and a second sliding lobe packs in a first direction, and a second groove configured to translate the first and a second sliding lobe packs in a second direction, opposite the first. A shift actuator has a first pin, a second pin, and a third pin, each selectively actuatable to engage the first groove or the second groove.

A valve train system for an internal combustion engine includes an exhaust valve moveable between an exhaust closed position and an exhaust open position. A camshaft includes a main exhaust lobe for moving the exhaust valve between the exhaust closed position and the exhaust open position for expelling exhaust constituents from the combustion chamber and an exhaust rebreath lobe for moving the exhaust valve between the exhaust closed position and the exhaust open position for allowing exhaust constituents into the combustion chamber. A two-step device is provided for transmitting motion from the camshaft to the exhaust valve and is switchable between a motion transmitting position and a motion preventing position such that the motion transmitting position allows motion to be transmitted from the exhaust rebreath lobe to the exhaust valve and the motion preventing position prevents motion from being transmitted from the exhaust rebreath lobe to the exhaust 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, a second arm also having a first end pivotally connected near the first end of the first arm, 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 employing a sensor attached to one of the first and second arms that can detect when the arms are moving relative to each other, and adapted to provide a signal indicating the sensed movement.

A method for diagnosing an electromagnetic actuator of a sliding cam valve drive of an internal combustion engine. An actuator pin is released by electrical energizing of the actuator and is introduced into a groove-like sliding slot which passes through a cylindrical slot section of the associated sliding cam-and ends in a slope onto the cylindrical circumference of the slot section. The method includes: energizing the actuator using current parameters of a variable actuator characteristic map so that the actuator pin is released when the cylindrical circumference overlaps the actuator pin circumferentially; determining whether the released actuator pin generates a rejection signal due to the slope from the sliding slot onto the cylindrical circumference; if no rejection signal is detected, repeating step a) whereas at least one current parameter is changed and step b); updating the actuator characteristic map with the changed current parameter.

A controller for controlling an internal combustion engine includes a valve timing adjuster, a variable valve lift mechanism and a processor. The processor controls a duty cycle of a drive signal in a selected one of control modes, thereby changing a relative rotational phase of a camshaft relative to an engine output shaft. The control modes include a specific control mode in which the duty cycle of the drive signal is adjusted to change a value of the current through a first motor. The processor performs, when changing the relative rotational phase through execution of the specific control mode, an abnormality diagnosis for the variable valve lift mechanism based on a comparison between the current value at the first motor and a reference current value. The processor sets the reference current value in accordance with a rotation angle of the output shaft of a second motor.

Methods and systems are provided for deactivating a valve actuation mechanism. In one example, a system may include a hydraulic gallery that may deliver a restricted flow of hydraulic fluid from a hydraulic flow restrictor to a pressure relief valve within a valve deactivation oil control valve, and during a second condition may deliver an unrestricted flow of hydraulic fluid from the valve deactivation oil control valve to the hydraulic flow restrictor. The hydraulic flow restrictor may comprise two vertical bores within the camshaft carrier that are fluidically coupled via a restrictive groove on the bottom surface of the camshaft carrier.

In a valve drive train device for an internal combustion engine of motor vehicle, wherein at least one axially movably mounted cam element including at least one cam set with at least two cam parts and a shifting gate with at least two gate track for converting a rotary movement of the cam element into an axial shifting motion, at least one of the cam parts and the adjacent gate track are disposed in an at least partially axially overlapping relationship for reducing thereby the axial length and the mass of the cam element or permitting the use of a larger, highly durable, actuating mechanism.