An internal combustion engine is configured to operate in a homogeneous-charge compression-ignition combustion mode and a spark-ignition combustion mode employing late intake valve closing. A method for operating the internal combustion engine includes determining an amount of residual gas re-inducted into a combustion chamber from a previous engine cycle and determining an amount of fresh air trapped in the combustion chamber for the present engine cycle based upon the amount of residual gas re-inducted into the combustion chamber from the previous engine cycle. Engine fueling to the cylinder for the present engine cycle is controlled based upon the amount of fresh air trapped in the combustion chamber for the present engine cycle.

A slider control module, based on a mode command: selectively extends pins into one or more slider actuators of a camshaft slider. Contact between the pins and the grooves in the slider actuator(s) during rotation of a camshaft slides the camshaft slider axially along the intake camshaft. An actual mode module: determines a last stored indicator of the mode command; commands the slider control module to extend one of the pins to slide the camshaft slider and achieve the last stored indicator of the mode command; and, based on whether the one of the pins extended in response to the command, indicates that an actual mode is either: (i) the last stored indicator of the mode command; or (ii) another mode. The mode command module updates the mode command to the actual mode.

A control method using a continuous variable valve duration apparatus implements a a continuous variable valve duration apparatus which includes a wheel mounted on a camshaft and having a wheel key so as to control duration of an intake valve of an engine, a cam unit having a cam and a cam key, adapted such that the camshaft is inserted thereinto, and being disposed so as to vary relative phase of the cam with respect to the camshaft, an inner bracket connected with the wheel key and the cam key, a slider housing being adapted such that the inner bracket is rotatably inserted thereinto and disposed so as to move vertically with respect to the engine, a controller varying a position of the slider housing so as to adjust rotation center of the inner bracket, and a guide unit guiding motion of the sliding housing. The control method includes calculating a required air amount for maintaining idle rotation speed of the engine by the controller when the engine is an idle state; mapping a supplied air amount in accordance with duration of the intake valve or the exhaust valve by the controller; setting a target valve duration for supplying the required air amount of the engine by the controller; and controlling duration of the intake valve or exhaust valve according to the set target valve duration by the controller.

A method for controlling valve timing of continuous variable valve duration engine may include continuous variable valve duration (CVVD) device and continuous variable valve timing (CVVT) device including determining target intake valve open (IVO) timing, target intake valve close (IVC) timing, target exhaust valve open (EVO) timing and target exhaust valve close (EVC) timing; determining target intake CVVD, target exhaust CVVD, target intake CVVT and target exhaust CVVT to satisfy the target IVO, IVC, EVO, and EVC timings; performing feedback control of the CVVD by learning minimum value of the CVVD and maximum value of the CVVD; performing feedback control of the CVVT based on profile information of the valve; and determining real IVO timing, real IVC timing, real EVO timing, and real EVC timing based on the feedback control of the CVVD and the feedback control of the CVVT.

Methods and systems are provided for reducing late burn induced cylinder pre-ignition events. Forced entry of residuals from a late burning cylinder into a neighboring cylinder may be detected based on engine block vibrations sensed in a window during an open exhaust valve of the late burning cylinder. In response to the entry of residuals, a pre-ignition mitigating action, such as fuel enrichment or deactivation, is performed in the neighboring cylinder.