A camshaft phaser arrangement configured for a concentric camshaft assembly having inner and outer camshafts is provided. The camshaft phaser arrangement includes a first camshaft phaser that is configured to be non-rotatably connected to both the inner and outer camshafts, and a second camshaft phaser that is configured to be non-rotatably connected to one of the inner or outer camshafts.

A method for controlling intake and exhaust valves of an engine may include: determining, by a controller, a target opening duration of the intake and exhaust valves based on an engine load and an engine speed; modifying, by an intake continuous variable valve duration (CVVD) device and by an exhaust CVVD device, current opening and closing timings of the intake valve and/or exhaust valve based on the target opening duration of the valves; and advancing or retarding, by the intake and/or exhaust CVVD devices, the current opening timing of the intake and exhaust valves while simultaneously retarding or advancing the current closing timing of the intake and exhaust valve by a predetermined value based on the target opening duration.

A camshaft phaser arrangement configured for a concentric camshaft assembly having inner and outer camshafts is provided. The camshaft phaser arrangement includes a first camshaft phaser, a second camshaft phaser, and a coupling that torsionally connects the first camshaft phaser to the second camshaft phaser. Each of the camshaft phasers is configured to be connected to either the inner or the outer camshaft. The coupling includes at least one flexible connector that provides for radial and axial movement between the first camshaft phaser and the second camshaft phaser.

A camshaft adjusting system (1) for a first camshaft (2) and a second camshaft (3) which are arranged concentrically with respect to one another is provided, with the second camshaft (3) being arranged within the first camshaft (2). A hydraulic camshaft adjuster (4) of the vane cell type is set up to adjust the first camshaft (2), and an electric camshaft adjuster (5) is set up to adjust the second camshaft (3). The second camshaft (3) is supported in the axial direction on a stator (6) of the hydraulic camshaft adjuster (4). Further, a camshaft adjusting unit is provided including the camshaft adjusting system (1) and two camshafts (2, 3).

A camshaft adjusting system (1) is provided for a first camshaft (2) and a second camshaft (3) which are arranged concentrically with respect to one another, the second camshaft (3) being arranged within the first camshaft (2). A vane-cell type hydraulic camshaft adjuster (4) is configured for adjusting the first camshaft (2) and an electric camshaft adjuster (5) is configured for adjusting the second camshaft (3). A front cover (7) which is fastened to a stator (6) of the hydraulic camshaft adjuster (4) and which closes off the camshaft adjuster (4) at a side facing away from the camshaft has an internal toothing (8) for supporting a flex pot (9) which is attached to the second camshaft (3) and which is designed for receiving torque from the electric camshaft adjuster (5). A camshaft adjusting unit having the camshaft adjusting system (1) and two camshafts (2, 3) is also provided.

A camshaft phaser arrangement configured for a concentric camshaft having inner and outer camshafts is provided. The camshaft phaser arrangement includes a first camshaft phaser and a second camshaft phaser. Each of the camshaft phasers is configured to be connected to either the inner or the outer camshaft. One or more couplers are arranged to torsionally couple the first camshaft phaser to the second camshaft phaser. A first end of the coupler is received by a radial slot configured within either the first or second phaser.

A camshaft adjusting system (1) is provided for a first camshaft (2) and a second camshaft (3) which are arranged concentrically with respect to one another, the second camshaft being arranged inside the first camshaft. A hydraulic camshaft adjuster (4) of the vane-cell type is set up for the adjustment of the first camshaft, and an electric camshaft adjuster (5) is set up for the adjustment of the second camshaft. A rotor contact flange (17) of an output ring (6) of the electric camshaft adjuster is arranged radially inside a first cover (23) of the hydraulic adjuster, the output ring which is equipped for the transmission of torque to the second camshaft is arranged at least partially radially and axially inside a rotor (7) of the hydraulic camshaft adjuster. A camshaft adjusting unit is also provided having a camshaft adjusting system of this type and two camshafts.

A camshaft phaser arrangement configured for a concentric camshaft assembly having inner and outer camshafts is provided. The camshaft phaser arrangement includes a first camshaft phaser, a second camshaft phaser, a coupling, and at least one timing wheel connected to at least one of the first or second camshaft phaser. Each of the camshaft phasers is configured to be connected to either the inner or the outer camshaft. The coupling includes a coupling ring and at least one coupling pin that torsionally connects the first camshaft phaser to the second camshaft phaser. The coupling provides for radial and axial movement between the first camshaft phaser and the second camshaft phaser.

Valve trains employing a splined interface between phaser(s) and a concentric camshaft, actuator at rear of camshaft actuated by an actuation rod, adding a clearance hole to the lobe pin for clearance to the actuation rod, supplying oil to camshaft bearings via the concentric camshaft inner tube, and bolt on front camshaft bearing. The valve trains may further employ a third rocker lever that is usable for a selectable valve event (e.g. compression release brake) while also implementing variable valve timing and a concentric camshaft.

A camshaft phaser arrangement configured for a concentric camshaft assembly having inner and outer camshafts is provided. The camshaft phaser arrangement includes a first camshaft phaser, a second camshaft phaser, a coupling, and at least one timing wheel connected to at least one of the first or second camshaft phaser. Each of the camshaft phasers is configured to be connected to either the inner or the outer camshaft. The at least one timing wheel defines at least one cutout that is configured to receive at least a portion of the coupling.