A method of providing a rocker arm set for a valvetrain includes providing a first rocker arm configured as a switching rocker arm for a first intake valve, and providing a second rocker arm configured as a fixed rocker arm for a second intake valve, the second rocker arm operating in a normal Otto cycle mode. The first rocker arm operates in a late intake valve closing (LIVC) mode where the first rocker arm is configured to close the first intake valve later than the second intake valve.

A hydraulic supply device for a valve stopping mechanism includes: a specific hydraulic oil supply passage which constantly supplies hydraulic oil, a valve stopping mechanism incorporated in a cylinder head, and configured to stop at least one of an intake valve and an exhaust valve, a valve stopping oil passage which supplies hydraulic oil to the valve stopping mechanism, a control valve which controls the supply of hydraulic oil to the valve stopping oil passage, and a communication oil passage which communicates between the valve stopping oil passage and the specific hydraulic oil supply passage, and provided with a restrictor therebetween. The specific hydraulic oil supply passage is connected to an oil supply portion for a portion to be lubricated or for a portion to be cooled in the engine at a position downstream of a connection position with respect to the communication oil passage in an oil supply direction.

Systems and methods for operating an engine with deactivating and non-deactivating valves are presented. In one example, engine volumetric efficiency actuators are adjusted in response to a request to activate engine cylinders so that engine intake manifold pressure is drawn down quickly toward its normal state at the engine's present speed and torque.

Methods and systems are provided for a cam carrier insert coupled to a cylinder head of an engine. In one example, a system may comprise: a cylinder head with a cam bearing tower; a cam carrier insert positioned in the cylinder head; and a camshaft, the camshaft directly supported by the cam bearing tower and directly supported by the cam carrier insert. By mounting a first portion of the cam shaft to the cam bearing tower and a second portion of the cam shaft on the cam carrier insert, the system may operate deactivatable and non-deactivatable intake or exhaust valves of one or more engine cylinders in the engine. In this way, packaging of engine components within the cylinder head may be improved while promoting better engine performance.

An eight cylinder engine includes cylinders that are fired at intervals corresponding to a crank angle of 90 degrees. The firing is conducted in four cylinders of each of first and second banks at uneven intervals. In a pair of cylinders of each of the banks in which the firing is consecutively conducted at an interval corresponding to a crank angle of 90 degrees, a central angle of an exhaust cam provided for one cylinder in which the firing is conducted later is larger than that of an exhaust cam provided for the other cylinder. In a pair of cylinders of each of the banks in which the firing is consecutively conducted at an interval corresponding to a crank angle of 270 degrees, a central angle of an exhaust cam provided for one cylinder in which the firing is conducted later is larger than that of an exhaust cam provided for the other cylinder.

A sliding camshaft is provided which may include a base shaft, an over-molded trigger wheel, and a distal axially movable structure. The distal axially movable structure may further include a distal journal in addition to at least one standard journal and lobe packs. A control groove is defined in the distal axially movable structure. The over-molded trigger wheel is mounted on the distal axially movable structure. The over-molded trigger wheel is operatively configured to move between at least a first position and a second position together with the distal axially movable structure via engagement between the control groove and an actuator. The over-molded trigger wheel may be press fitted on distal axially movable structure and is adapted to accurately communicate with a sensor regardless of the position of the distal axially movable structure.

A method for controlling engine operations, is provided herein. The engine includes at least a first bank having a first cylinder and a second cylinder associated with at least a turbocharger or an exhaust gas recirculation system. Each of the first and the second cylinder has a respective intake valve. The method determines an exhaust back pressure for each one of the first and the second cylinder. Further, the method determines an intake mass flow rate for each one of the first and the second cylinder based at least on the determined exhaust back pressure for the respective first and the second cylinder. The method adjusts a time duration of an open position of the respective intake valve for each one of the first and the second cylinder based on the determined intake mass flow rate for the corresponding first and the second cylinder.

A variable camshaft includes a base shaft, an axially movable structure, and an actuator. The axially movable structure includes a plurality of lobe packs and at least one barrel cam defining a control groove having an engagement region, a first shift region, a balancing region, a second shift region and a disengagement region. The actuator includes at least one pin operatively configured to move relative to the actuator body between a retracted position and an extended position into the control groove. The axially movable structure moves axially relative to the base shaft the pin is in the extended position and is at least partially disposed in one of the first or second shift regions of the control groove.

To improve fuel efficiency, some gasoline engines are equipped with valve deactivators in some of the cylinders so that at low torque conditions only a subset of the total number of cylinders are active. In prior art engines, particularly when they have four valves per cylinder, space is tight. It is known to provide a cam carrier in the head between the cylinder head and the camshaft. The cylinder head bolts pass through the head under the cam carrier. According to the present disclosure, the cam carrier, and its associated disadvantages, is obviated by widening the bearings for the camshafts, using smaller diameter head bolts, and putting the orifices tor the head bolts directly through the bearings.

Systems and methods are provided for controlling boost pressure in an engine system with a parallel turbocharger. One example method includes, responsive to a first condition, deactivating a first compressor of a first turbocharger, activating each first exhaust valve of each cylinder of an engine, and deactivating each second exhaust valve of each cylinder of the engine to flow exhaust gas from the engine to a second turbocharger. The method further includes, responsive to boost pressure exceeding a threshold, maintaining deactivation of the first compressor, reactivating each second exhaust valve to flow exhaust gas from the engine to both the first turbocharger and second turbocharger, and driving an electric assist device via a first turbine of the first turbocharger.