A valve timing adjusting device adjusts an opening/closing timing of a first valve driven by a rotation of a first camshaft and an opening/closing timing of a second valve driven by a rotation of a second camshaft. The valve timing adjusting device includes a first driving circuit controlling a first motor configured to generate a torque to shift a rotation phase of the first camshaft and a second driving circuit controlling a second motor configured to generate a torque to shift a rotation phase of the second camshaft. A first switching element of the first driving circuit operates at a switching frequency that is different from that of a second switching element of the second driving circuit.

A variable camshaft timing system including a first camshaft phaser having an input that is configured to receive rotational force from a crankshaft and an output that is configured to link with a first camshaft of a concentric camshaft assembly to change the angular position of the first camshaft relative to a crankshaft; and a second camshaft phaser having an output that is configured to link with a second camshaft of the concentric camshaft assembly to change the angular position of the second camshaft relative to the crankshaft, wherein the first camshaft is concentrically positioned to the first camshaft and the first camshaft phaser is mechanically linked to the second camshaft phaser to communicate rotational force from the crankshaft to the second camshaft phaser through the first camshaft phaser and the mechanical link.

A camshaft phaser assembly, including: an axis of rotation; a hydraulic camshaft phaser including a stator arranged to receive rotational torque and including a plurality of radially inwardly extending protrusions, a rotor arranged to be non-rotatably connected to a first camshaft and including a plurality of radially outwardly extending protrusions circumferentially interleaved with the plurality of radially inwardly extending protrusions, and a plurality of chambers bounded at least in part by the plurality of radially inwardly extending protrusions and the plurality of radially outwardly extending protrusions; an electric camshaft phaser including an output gear arranged to be non-rotatably connected to a second camshaft located concentrically within the first camshaft and an input non-rotatably connected to the stator; and a connection plate non-rotatably connecting the input and the stator. The rotor and the output gear are rotatable with respect to each other about the axis of rotation.

A valve timing adjusting device adjusts an opening/closing timing of a first valve driven by a rotation of a first camshaft and an opening/closing timing of a second valve driven by a rotation of a second camshaft. The valve timing adjusting device includes a first driving circuit controlling a first motor configured to generate a torque to shift a rotation phase of the first camshaft and a second driving circuit controlling a second motor configured to generate a torque to shift a rotation phase of the second camshaft. A first switching element of the first driving circuit operates at a switching frequency that is different from that of a second switching element of the second driving circuit.

A hybrid dual phaser assembly is disclosed for mounting to an engine camshaft to allow the timing of two sets of cam lobes to be phased independently of one another relative to a crankshaft of the engine. The phaser assembly comprises an electrically operated phaser having intermeshing gears for transmitting torque to the camshaft and a phase control input driven by an electric motor to be mounted coaxially with the camshaft, and a hydraulically operated phaser having vanes movable within arcuate cavities. The cavities of the hydraulically operated phaser are defined in part by an annular member that radially surrounds, and axially overlaps, a gear of the electrically operated phaser, which gear is separate from the annular member and forms radially inner boundary walls of the cavities.

A variable camshaft timing system including a first camshaft phaser having an input that is configured to receive rotational force from a crankshaft and an output that is configured to link with a first camshaft of a concentric camshaft assembly to change the angular position of the first camshaft relative to a crankshaft; and a second camshaft phaser having an output that is configured to link with a second camshaft of the concentric camshaft assembly to change the angular position of the second camshaft relative to the crankshaft, wherein the first camshaft is concentrically positioned to the first camshaft and the first camshaft phaser is mechanically linked to the second camshaft phaser to communicate rotational force from the crankshaft to the second camshaft phaser through the first camshaft phaser and the mechanical link.

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 non-rotatably connects the first camshaft phaser to the concentric camshaft assembly. Each of the camshaft phasers is configured to be connected to either the inner or the outer camshaft. The coupling accommodates for radial and axial offset between the first camshaft phaser and the second camshaft phaser.

A variable camshaft timing (VCT) assembly for changing the angular position of concentric camshafts relative to a crankshaft includes a coupling plate having a first plurality of Oldham features configured to engage a first plurality of Oldham receiving features carried by a first VCT device and a second plurality of Oldham features configured to engage a second plurality of Oldham receiving features carried by a second VCT device; the coupling plate is positioned axially between the first VCT device and the second VCT device permitting the first VCT device and the second VCT device to move radially outwardly and inwardly relative to an axis of camshaft rotation.

A camshaft phaser assembly, including: an axis of rotation; a first hydraulic camshaft phaser including a first stator arranged to receive rotational torque, a first rotor including a plurality of first through-bores, and a first plurality of phaser chambers circumferentially bounded by the first stator and the first rotor; a second hydraulic camshaft phaser including a second stator non-rotatably connected to the first stator, a second rotor, and a second plurality of phaser chambers circumferentially bounded by the second stator and the second rotor; a first trigger wheel including a plurality of second through-bores connected to the plurality of first through-bores, non-rotatably connected to the first rotor, and arranged to identify a rotational position of the first rotor; and a second trigger wheel non-rotatably connected to the second rotor and arranged to identify a rotational position of the second rotor.

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.