A continuous variable valve duration apparatus may include: a camshaft; first and second cam portions on which a cam is formed respectively; first and second inner brackets transmitting rotation of the camshaft to the first and second cam portions respectively; a slider housing in which the first and the second inner brackets are rotatably inserted; first and second guiding portions formed on the slider housing; a control shaft parallel to the camshaft; a control rod eccentrically formed on the control shaft; a guide head on which a head guiding portion and a head hole are formed; a cam cap supporting the control shaft; a cam cap guiding portion mounted to the cam cap; and a control portion selectively rotating the control shaft such that the slider housing is moved along the cam cap guiding portion.

An exhaust gas control apparatus includes a first catalyst, a filter, and an electronic control unit. The electronic control unit is configured to alternately execute lean control and rich control multiple times. The lean control is control for, over a period longer than a period from when a target air-fuel ratio is set to a predetermined lean air-fuel ratio until an air-fuel ratio of exhaust gas flowing out from the first catalyst becomes greater than the stoichiometric air-fuel ratio, setting the target air-fuel ratio to the predetermined lean air-fuel ratio. The rich control is control for, over a period longer than a period from when the target air-fuel ratio is set to a predetermined rich air-fuel ratio until the air-fuel ratio of exhaust gas flowing out from the first catalyst becomes smaller than the stoichiometric air-fuel ratio, setting the target air-fuel ratio to the predetermined rich air-fuel ratio.

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.

An internal combustion engine includes a variable mechanism that changes a working angle of an intake valve. A controller diagnoses whether there is an abnormality that an intake air amount reduces during idle operation. The controller changes an abnormality determination threshold for diagnosing an abnormality on the basis of a mode in which the working angle is changed by the variable mechanism.

A valve actuation system is disclosed for an engine. The valve actuation system may have a variable valve actuator that is configured to engage a rocker arm and hold the valve at an open position regardless of motion of a cam lobe. The variable valve actuator may have a housing forming a chamber, a plunger disposed in the chamber, a control valve movable to control a flow of fluid into the chamber, and a relief valve configured to automatically open and release fluid from the housing when a pressure inside the chamber is below a predetermined pressure. The valve actuation system may further have a controller configured to cycle the control valve prior to start-up of the engine and to selectively move the control valve after start-up.

A method of controlling valve timing and valve duration using a CVVT apparatus and a CVVD apparatus, the CVVT apparatus being configured to adjust an opening time of a valve in a vehicle engine, the CVVD apparatus being configured to adjust a duration of a valve lift, the method may include determining a desired valve opening time and a desired valve closing time; determining a desired valve duration by the desired valve opening time and the desired valve closing time; determining a desired valve timing through the desired valve opening time and an actual valve duration measured in real time; and controlling the CVVD apparatus to accomplish the desired valve duration while controlling the CVVT apparatus to accomplish the desired valve timing.

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 switchable rocker arm for valve deactivation is provided for a valve train of an internal combustion engine. The switchable rocker arm includes a valve side lever assembly, a cam side lever assembly, and a hydraulically actuated coupling assembly. The valve side lever assembly includes a first housing with a first rocker shaft bore. The cam side lever assembly includes a second housing with a first arm with a second rocker shaft bore and a second arm with a third rocker shaft bore. The first and second arms extend along opposed longitudinal sides of the cam side lever assembly such that the first, second and third rocker shaft bores are axially aligned. The coupling assembly is arranged at an end furthest away from a pivot axis for minimal loading and provides locking and unlocking of the switchable rocker arm to achieve full valve lift and no valve lift modes, respectively.

A method for controlling intake and exhaust valves of an engine includes: controlling, by an intake continuous variable valve timing (CVVT) device and an exhaust CVVT device, opening and closing timings of the intake valve and exhaust valves; 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 two-stage variable valve duration device, current opening and closing timings of the intake valve and exhaust valve based on the target opening durations. In particular, the exhaust two-stage VVD device switches a current opening duration of the exhaust valve to a first exhaust opening duration or a second exhaust opening duration which is shorter than the first opening duration based on the target opening duration of the exhaust valve.

A method for controlling intake and exhaust valves of an engine includes: controlling, by an intake continuous variable valve timing (CVVT) device, opening and closing timings of the intake valve; controlling, by an exhaust CVVT device, opening and closing timing of the exhaust valve; determining, by a controller, first to fifth control regions based on engine load and speeds, and a target opening duration of the intake valve and target opening or target closing timings of the intake valve; modifying, by an intake continuous variable valve duration (CVVD) device, current opening and closing timings of the intake valve based on the target opening duration; and advancing or retarding, by the intake CVVD device, the current opening timing of the intake valve while simultaneously retarding or advancing the current closing timing of the intake valve by a predetermined value based on the target opening duration of the intake valve.