A method of continuously variable valve duration (CVVD) location learning may include when a controller determines necessity of position learning for short duration and long duration of a CVVD system, performing conditional application re-learning control in which the position learning is performed in a situation in which validity determination of system environment condition for CVVD hardware and validity determination of vehicle environment condition for engine operation information of an engine are satisfied.

A valvetrain service tool for an automobile engine comprises a bracket adapted to be removably mounted onto a structural member of an engine, and a pin slidably supported within the bracket, wherein, the pin is slidable between a first position and a second position, further wherein, when the pin is moved from the first position to the second position, the pin engages a cam sprocket of the engine to support the cam sprocket and allow service to be performed to the valvetrain of the engine without removing the cam sprocket.

A control device for an engine 1 including cylinders, and configured to perform a reduced-cylinder operation by idling some of cylinders. The control device includes a hydraulic valve-stopping mechanism 14b which closes the intake and exhaust valves 41, 51 of the cylinders in response to establishment of the reduced-cylinder operation execution condition, a hydraulic variable valve timing mechanism 19 capable of changing a phase of the exhaust valve 51 of the engine 1, and an ECU 110 which controls the valve-stopping mechanism 14b and the hydraulic variable valve timing mechanism 19. In response to establishment of the reduced-cylinder operation execution condition, the ECU 110 allows the hydraulic variable valve timing mechanism 19 to execute the phase change to the exhaust valve 51, and subsequently allows the valve-stopping mechanism 14b to bring the intake and exhaust valves 41, 51 of the cylinders into closed state.

A rocker arm includes an outer arm having a first side and a second side, an inner arm positioned between the first side and the second side of the outer arm, a pivot axle pivotally coupling the inner arm and the outer arm at a first end of each of the inner arm and the outer arm, and a latch having a first position and a second position. The latch in the first position pivotally fixes the inner arm and the outer arm at a second end of each of the inner arm and the outer arm, and in the second position allows the inner arm and the outer arm to pivot independently. The latch is responsive to hydraulic pressure in a hydraulic fluid passage to selectively move to other of the first position and the second position. A lost motion spring is coupled to the inner arm.

A rocker arm includes an outer arm having a first side and a second side, an inner arm positioned between the first side and the second side of the outer arm, a pivot axle pivotally coupling the inner arm and the outer arm at a first end of each of the inner arm and the outer arm, and a latch having a first position and a second position. The latch in the first position pivotally fixes the inner arm and the outer arm at a second end of each of the inner arm and the outer arm, and in the second position allows the inner arm and the outer arm to pivot independently. The latch is responsive to hydraulic pressure in a hydraulic fluid passage to selectively move to other of the first position and the second position. A lost motion spring is coupled to the inner arm.

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.

Methods and systems are provided for controlling camshaft phasers of a variable displacement engine. In one example, the engine includes first and second cylinder banks, with the engine being configured to operate in a rolling variable displacement mode. The camshaft phasers are torque actuated camshaft phasers, and a controller of the engine may adjust operation of camshaft phasers at the first cylinder bank differently than camshaft phasers at the second cylinder bank.

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.

A method for operating an internal combustion engine having a camshaft phase adjuster, including: providing a nonlinear final control element model, which indicates via a functional relationship an angular velocity of a relative adjustment of the camshaft phase adjuster as a function of an actuator correcting variable for the control of the camshaft phase adjuster; carrying out a control based on a deviation between a predefined camshaft angle adjustment setpoint value, and a camshaft angle adjustment actual value, to obtain as a control output a setpoint positioning rate of the camshaft phase adjuster; calculating the actuator correcting variable as a function of the setpoint positioning rate using an inverted final control element model; applying a predefined correction variable to the actuator correcting variable; controlling the camshaft phase adjuster using the actuator correcting variable to which the correction variable has been applied, to operate the internal combustion engine.

A vehicle includes a variable displacement engine and a controller. The variable displacement engine has a plurality of cylinders and is configured to operate at a commanded air-fuel ratio. The controller is programmed to, in response to a command to perform a diagnostic test, operate the engine such that each of the cylinders is shut down for a portion of the diagnostic test while one or more of the remainder of the cylinders remain operating. The controller is further programmed to, in response to a deviation from the commanded air-fuel ratio exceeding a threshold while a first of the cylinders is shut down during the diagnostic test and a subsequent command to decrease the number of operating cylinders, shut down one or more of the plurality of cylinders other than the first of the cylinders.