An internal combustion engine includes a cylinder and a valve assembly configured to activate and deactivate the at least one cylinder. The valve assembly includes an intake valve configured to control air flow into the at least one cylinder. A controller outputs a first control signal to the valve assembly to deactivate the at least one cylinder in response to detecting a deceleration event. The controller also outputs a second control signal to command the valve assembly to delay opening the intake valve from a closed position after re-activating the cylinder so that the torque output produced in response to re-activating the cylinder is reduced.

An engine system includes a first camshaft, a second camshaft, a first camshaft phaser, and a second camshaft phaser. The first camshaft phaser has a first camshaft sprocket, and the second camshaft phaser has a second camshaft sprocket. The engine system also includes a crankshaft spaced from the first and second camshafts, and a crankshaft sprocket coupled to the crankshaft. The engine system further includes a timing chain coupled to the first and second camshaft sprockets, and the crankshaft sprocket. The timing chain is configured to transmit torque from the crankshaft sprocket to the first and second camshaft sprockets upon rotation of the crankshaft. The engine system further includes a biasing member extending from a first end portion coupled to the first camshaft phaser to a second end portion coupled to the second camshaft phaser to maintain tension on the timing chain between the first and second camshaft phasers.

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 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.

A chain cover is configured to cover a timing chain that transmits rotation of a crankshaft of an internal combustion engine to a camshaft. The chain cover includes a crankshaft-side opening forming portion that defines a crankshaft-side opening into which the crankshaft is inserted, and a general portion that is a section different from the crankshaft-side opening forming portion. The crankshaft-side opening forming portion is made of a first material. The general portion is made of a second material. The first material and the second material are different from each other.

The present disclosure employs a pair of camshafts for intake valves. A first phase controller is installed at a first end of the first intake camshaft connecting to a crankshaft. A second phase controller is installed at a second end of the first intake camshaft connecting to a second intake camshaft. Each phase controller can advance or retard phase angles to modify intake valve timing and intake valve lift. This set up is duplicated for the exhaust valves to modulate exhaust valve timing and exhaust valve lift. First and second camshafts are connected via a series of levers, which merge rotational outputs of both camshafts into one. The phase controllers can be differential gear sets, epicyclical gear sets, or a combination thereof.

The number of advance chambers is larger than the number of retard chambers in an intake variable valve timing (VVT), whereas the number of retard chambers is larger than the number of advance chambers in an exhaust VVT. Accordingly, with limitation of an oil pressure that can be used by the VVTs, a pumping loss in a transition period in which a valve overlap amount is changed by advancing or retarding a valve timing can be reduced.

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.

Various embodiments include a method for identifying an inlet and an outlet valve stroke phase difference comprising: measuring pressure oscillations during operation; generating a corresponding signal; determining a corresponding crankshaft phase angle; applying a discrete Fourier transformation to the pressure signal to determine amplitudes of selected frequencies in relation to the crankshaft phase angle; determining lines of equal amplitudes of the frequencies based on the amplitudes depending on the phase differences using reference lines; determining an intersection of the lines by projection into a common plane; and determining the inlet valve stroke phase difference and the outlet valve stroke phase difference from the determined common intersection point of the lines of equal amplitudes of the selected signal frequencies.

Various embodiments include a method for identifying valve stroke phase differences during operation comprising: measuring dynamic pressure oscillations in the air intake tract; generating a corresponding signal; acquiring a crankshaft phase angle; acquiring the phase position and the amplitude of a signal frequency of the oscillations based on the pressure oscillation using discrete Fourier transformation; acquiring a line of an equal phase position and of equal amplitude of the signal frequency reflecting the inlet and the outlet stroke phase difference using reference lines; acquiring a common intersection point of a line of equal phase position and a line of equal amplitude by projection into a common plane; and determining the stroke phase differences and from the common intersection point.