A durable system for controlling variable valve actuation of an engine valve corresponding to a cylinder of an automobile engine. The system includes first and second crowned cams having first and second lift profiles and a rocker arm assembly. The rocker assembly includes a first arm having an end connected to said engine valve, having a high impact roller following the first crowned cam operating the engine valves according to a first lift profile. The rocker arm assembly also includes a second arm having durable slider pads riding on the second crowned cam to operate said engine valve according to a second lift profile. A latch secures the second arm relative to the first arm when in a latched position causing the valve to operate according to a second lift profile. The valve operates according to a first lift profile when the latch is not in the latched position.

A durable system for controlling variable valve actuation of an engine valve corresponding to a cylinder of an automobile engine. The system includes first and second crowned cams having first and second lift profiles and a rocker arm assembly. The rocker assembly includes a first arm having an end connected to said engine valve, having a high impact roller following the first crowned cam operating the engine valves according to a first lift profile. The rocker arm assembly also includes a second arm having durable slider pads riding on the second crowned cam to operate said engine valve according to a second lift profile. A latch secures the second arm relative to the first arm when in a latched position causing the valve to operate according to a second lift profile. The valve operates according to a first lift profile when the latch is not in the latched position.

Methods and systems are described for an engine with a cam torque actuated variable cam timing phaser. Phaser positioning control is improved by reducing inaccuracies resulting from inadvertent spool valve and/or phaser movement when the spool valve is commanded between regions. In addition, improved spool valve mapping is used to render phaser commands more consistent and robust.

Methods and systems are described for an engine with a cam torque actuated variable cam timing phaser. Phaser positioning control is improved by reducing inaccuracies resulting from inadvertent spool valve and/or phaser movement when the spool valve is commanded between regions. In addition, improved spool valve mapping is used to render phaser commands more consistent and robust.

Methods and systems are described for an engine with a cam torque actuated variable cam timing phaser. Phaser positioning control is improved by reducing inaccuracies resulting from inadvertent spool valve and/or phaser movement when the spool valve is commanded between regions. In addition, improved spool valve mapping is used to render phaser commands more consistent and robust.

Methods and systems are described for an engine with a cam torque actuated variable cam timing phaser. Phaser positioning control is improved by reducing inaccuracies resulting from inadvertent spool valve and/or phaser movement when the spool valve is commanded between regions. In addition, improved spool valve mapping is used to render phaser commands more consistent and robust.

A method for ascertaining a valve position of a valve of an internal combustion engine having a multiplicity of valves. The method includes illuminating a combustion chamber of the internal combustion engine, detecting light emerging from the illuminated combustion chamber on a side, averted from the combustion chamber, of the valve for ascertainment, and determining the valve position of the valve for ascertainment by way of the detected light.

The disclosure relates to a camshaft adjustment system comprising a hydraulic camshaft adjuster having a stator and a rotor forming at least one working chamber. The at least one working chamber is divided into a first sub-chamber and a second sub-chamber The sub-chambers interact with a control valve controllable via a first actuator. When the first sub-chamber undergoes a volume increase, the rotor is displaced into a late position relative to the stator, and when the second sub-chamber undergoes a volume increase, the rotor is displaced into an early position relative to the stator. A second actuator actuated independently of the first actuator is provided. In order to release the camshaft adjuster from the late position when in an operating state, a ram of the second actuator displaces a locking pin of a late-locking device of the camshaft adjuster out of its position that locks the late position.