Various embodiments include a method for detecting deviations occurring in the valve drive of an internal combustion engine comprising: measuring dynamic pressure oscillations of intake air in an air intake tract of respective internal combustion engine during operation; calculating an inlet valve stroke phase difference and/or an outlet valve stroke phase difference based on the measured dynamic pressure oscillation; calculating a valve stroke phase deviation value with respect to a valve stroke phase reference value based on the calculated phase difference; and calculating a first valve drive deviation value based on the valve stroke phase deviation value.

A method for adaptation of a detected camshaft position of a camshaft in an internal combustion engine with: Detection of an ACTUAL gas signal in a gas space that is associated with the camshaft and is associated with a detected camshaft position; Processing of the gas signal to produce an ACTUAL gas criterion; Modeling of multiple simulated gas criteria, each of which is associated with a target camshaft position; Determination of a simulated gas criterion with the least deviation from the ACTUAL gas criterion; Determination of an ACTUAL camshaft position that corresponds to the simulated gas criterion with the least deviation from the ACTUAL gas criterion; Determination of a camshaft position correction value from the difference between the ACTUAL camshaft position determined and the detected camshaft position; Determination of corrected camshaft positions by correcting the detected camshaft positions with the camshaft position correction value.

A method for an alternate control of a continuously variable valve duration (CVVD) malfunction may include a CVVD failsafe control to resolve a calculation error of a cylinder charge amount due to a hardware failure of a CVVD system with the cylinder charge amount determined by any one of flow rate alternate, flow rate deviation correction, and valve duration update if the hardware failure is recognized by a CVVD controller, and to apply the cylinder charge amount to secure an air amount for a combustion chamber.

When an EDU determines that a motor is in a control unstable state where the motor cannot be controlled to a target rotation speed due to a drive voltage output duty value being smaller than a threshold value, the EDU performs a control point shifting operation to shift a control point between a first control point, which is in the control unstable state, and a second control point, which is a control stable state outside the control unstable state. Thus, even when the motor is in a stepping rotation state, it is possible to control the target rotation speed regardless of influence of a cogging torque, and appropriately control the cam phase of the intake camshaft to a target phase when the engine is stopped.

A continuously variable valve duration (CVVD) system includes an electronic control unit (ECU) configured to output a command for adjusting an actuator and a controller configured to determine a operation range of a control shaft of the actuator and adjust the control shaft in the determined operation range based on the command of the ECU. The controller positions the control shaft at a predetermined target phase and determines a control state of each target phase based on a target phase value transmitted from the actuator when the control shaft is positioned at the target phase.

Methods and systems are provided for diagnosing a cylinder valve deactivation mechanism in an engine system having cam-actuated valves. Movement of a latch pin of the deactivation mechanism is inferred from an induction current generated by a solenoid coupled to the latch pin, and the inferred movement is used to diagnose operation of cylinder valve deactivation mechanism. The inferred movement and a profile of the induction current is also used to estimate camshaft and crankshaft timing for improved cylinder fuel delivery in the absence of a camshaft sensor.

A target wheel for a camshaft phaser, including: a radially disposed wall facing in a first axial direction; a first circumferentially disposed wall connected to the radially disposed wall; a second circumferentially disposed wall connected to the radially disposed wall; and a first tab directly connected to the first circumferentially disposed wall and the second circumferentially disposed wall, extending radially outward past the first circumferentially disposed wall and the second circumferentially disposed wall, and including a heat-treated portion.

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.

A method for an alternate control of a continuously variable valve duration (CVVD) malfunction may include a CVVD failsafe control to resolve a calculation error of a cylinder charge amount due to a hardware failure of a CVVD system with the cylinder charge amount determined by any one of flow rate alternate, flow rate deviation correction, and valve duration update if the hardware failure is recognized by a CVVD controller, and to apply the cylinder charge amount to secure an air amount for a combustion chamber.